Increased vessel density along with a reduction in fibrosis decreases the efficacy of chemotherapy treatments.

Cancer-Associated Fibroblasts Neutralize the Anti-tumor Effect of CSF1 Receptor Blockade by Inducing PMN-MDSC Infiltration of Tumors.

Tumor-associated macrophages (TAM) contribute to all aspects of tumor progression. Use of CSF1R inhibitors to target TAM is therapeutically appealing, but has had very limited anti-tumor effects. Here, we have identified the mechanism that limited the effect of CSF1R targeted therapy. We demonstrated that carcinoma-associated fibroblasts (CAF) are major sources of chemokines that recruit granulocytes to tumors. CSF1 produced by tumor cells caused HDAC2-mediated downregulation of granulocyte-specific chemokine expression in CAF, which limited migration of these cells to tumors. Treatment with CSF1R inhibitors disrupted this crosstalk and triggered a profound increase in granulocyte recruitment to tumors. Combining CSF1R inhibitor with a CXCR2 antagonist blocked granulocyte infiltration of tumors and showed strong anti-tumor effects.

Anaphase catastrophe is a target for cancer therapy.

Neoplastic cells are genetically unstable. Strategies that target pathways affecting genome instability can be exploited to disrupt tumor cell growth, potentially with limited consequences to normal cells. Chromosomal instability (CIN) is one type of genome instability characterized by mitotic defects that increase the rate of chromosome mis-segregation. CIN is frequently caused by extra centrosomes that transiently disrupt normal bipolar spindle geometry needed for accurate chromosome segregation. Tumor cells survive with extra centrosomes because of biochemical pathways that cluster centrosomes and promote chromosome segregation on bipolar spindles. Recent work shows that targeted inhibition of these pathways prevents centrosome clustering and forces chromosomes to segregate to multiple daughter cells, an event triggering apoptosis that we refer to as anaphase catastrophe. Anaphase catastrophe specifically kills tumor cells with more than 2 centrosomes. This death program can occur after genetic or pharmacologic inhibition of cyclin dependent kinase 2 (Cdk2) and is augmented by combined treatment with a microtubule inhibitor. This proapoptotic effect occurs despite the presence of ras mutations in cancer cells. Anaphase catastrophe is a previously unrecognized mechanism that can be pharmacologically induced for apoptotic death of cancer cells and is, therefore, appealing to engage for cancer therapy and prevention.

An IL-13 inhibitor blocks the development of hepatic fibrosis during a T-helper type 2-dominated inflammatory response.

In schistosomiasis, chronic parasite egg-induced granuloma formation can lead to tissue destruction and fibrosis, which causes much of the morbidity and mortality associated with this disease. Here we show the importance of IL-13 in the pathogenesis of schistosomiasis, and demonstrate, perhaps for the first time, the therapeutic efficacy of an IL-13 inhibitor, sIL-13Ralpha2-Fc, in the control of hepatic fibrosis. T-helper type 2 (Th2) cytokines dominate the immune response in mice infected with Schistosoma mansoni, yet the specific contributions of IL-13 and IL-4 to the development of fibrosis were not previously investigated. Our studies demonstrate that both cytokines play redundant roles in granuloma formation, which explains the ability of IL-4-deficient mice to form granulomas around eggs. More importantly, however, these studies demonstrate that IL-13 is the dominant Th2-type cytokine regulating fibrosis. IL-13 stimulated collagen production in fibroblasts, and procollagen I and procollagen III mRNA expression was decreased in sIL-13Ralpha2-Fc-treated mice. Moreover, the reduction in fibrosis observed in IL-4-deficient mice was much less pronounced than that in sIL-13Ralpha2-Fc-treated animals. Fibrosis is a major pathological manifestation of a number of allergic, autoimmune, and infectious diseases. Thus, our findings provide evidence that IL-13 inhibitors may be of general therapeutic benefit in preventing damaging tissue fibrosis resulting from Th2-dominated inflammatory responses.

Efficacy of Beta1 Integrin and EGFR Targeting in Sphere-Forming Human Head and Neck Cancer Cells

BACKGROUND Resistance to radiotherapy continues to be a limiting factor in the treatment of cancer including head and neck squamous cell carcinoma (HNSCC). Simultaneous targeting of β1 integrin and EGFR was shown to have a higher radiosensitizing potential than mono-targeting in the majority of tested HNSCC cancer models. As tumor-initiating cells (TIC) are thought to play a key role for therapy resistance and recurrence and can be enriched in sphere forming conditions, this study investigated the efficacy of β1 integrin/EGFR targeting without and in combination with X-ray irradiation on the behavior of sphere-forming cells (SFC). METHODS HNSCC cell lines (UTSCC15, UTSCC5, Cal33, SAS) were injected subcutaneously into nude mice for tumor up-take and plated for primary and secondary sphere formation under non-adhesive conditions which is thought to reflect the enrichment of SFC and their self-renewal capacity, respectively. Treatment was accomplished by inhibitory antibodies for β1 integrin (AIIB2) and EGFR (Cetuximab) as well as X-ray irradiation (2 - 6 Gy single doses). Further, flow cytometry for TIC marker expression and cell cycling as well as Western blotting for DNA repair protein expression and phosphorylation were employed. RESULTS We found higher primary and secondary sphere forming capacity of SAS cells relative to other HNSCC cell lines, which was in line with the tumor up-take rates of SAS versus UTSCC15 cells. AIIB2 and Cetuximab administration had minor cytotoxic and no radiosensitizing effects on SFC. Intriguingly, secondary SAS spheres, representing the fraction of surviving SFC upon passaging, showed greatly enhanced radiosensitivity compared to primary spheres. Intriguingly, neither AIIB2 nor Cetuximab significantly altered basal sphere forming capacity and radiosensitivity. While an increased accumulation of G0/G1 phase cells was observable in secondary SAS spheres, DNA double strand break repair indicated no difference on the basis of significantly enhanced ATM and Chk2 dephosphorylation upon irradiation. CONCLUSIONS In the HNSCC model, sphere-forming conditions select for cells, which are unsusceptible to both anti-β1 integrin and anti-EGFR inhibitory antibodies. With regard to primary and secondary sphere formation, our data suggest that both of these SFC fractions express distinct survival strategies independent from β1 integrin and EGFR and that future work is warranted to better understand SFC survival and enrichment before and after treatment to untangle the underlying mechanisms for identifying novel, druggable cancer targets in SFC.

Radiation and Dual Checkpoint Blockade Activates Non-Redundant Immune Mechanisms in Cancer

Immune checkpoint inhibitors result in impressive clinical responses, but optimal results will require combination with each other and other therapies. This raises fundamental questions about mechanisms of non-redundancy and resistance. Here we report major tumour regressions in a subset of patients with metastatic melanoma treated with an anti-CTLA4 antibody (anti-CTLA4) and radiation, and reproduced this effect in mouse models. Although combined treatment improved responses in irradiated and unirradiated tumours, resistance was common. Unbiased analyses of mice revealed that resistance was due to upregulation of PD-L1 on melanoma cells and associated with T-cell exhaustion. Accordingly, optimal response in melanoma and other cancer types requires radiation, anti-CTLA4 and anti-PD-L1/PD-1. Anti-CTLA4 predominantly inhibits T-regulatory cells (Treg cells), thereby increasing the CD8 T-cell to Treg (CD8/Treg) ratio. Radiation enhances the diversity of the T-cell receptor (TCR) repertoire of intratumoral T cells. Together, anti-CTLA4 promotes expansion of T cells, while radiation shapes the TCR repertoire of the expanded peripheral clones. Addition of PD-L1 blockade reverses T-cell exhaustion to mitigate depression in the CD8/Treg ratio and further encourages oligoclonal T-cell expansion. Similarly to results from mice, patients on our clinical trial with melanoma showing high PD-L1 did not respond to radiation plus anti-CTLA4, demonstrated persistent T-cell exhaustion, and rapidly progressed. Thus, PD-L1 on melanoma cells allows tumours to escape anti-CTLA4-based therapy, and the combination of radiation, anti-CTLA4 and anti-PD-L1 promotes response and immunity through distinct mechanisms.

IAP regulation of metastasis.

Inhibitor-of-Apoptosis (IAP) proteins contribute to tumor progression, but the requirements of this pathway are not understood. Here, we show that intermolecular cooperation between XIAP and survivin stimulates tumor cell invasion and promotes metastasis. This pathway is independent of IAP inhibition of cell death. Instead, a survivin-XIAP complex activates NF-kappaB, which in turn leads to increased fibronectin gene expression, signaling by beta1 integrins, and activation of cell motility kinases FAK and Src. Therefore, IAPs are direct metastasis genes, and their antagonists could provide antimetastatic therapies in patients with cancer.

Crowding induces live cell extrusion to maintain homeostatic cell numbers in epithelia

For an epithelium to provide a protective barrier, it must maintain homeostatic cell numbers by matching the number of dividing cells with the number of dying cells. Although compensatory cell division can be triggered by dying cells, it is unknown how cell death might relieve overcrowding due to proliferation. When we trigger apoptosis in epithelia, dying cells are extruded to preserve a functional barrier. Extrusion occurs by cells destined to die signalling to surrounding epithelial cells to contract an actomyosin ring that squeezes the dying cell out. However, it is not clear what drives cell death during normal homeostasis. Here we show in human, canine and zebrafish cells that overcrowding due to proliferation and migration induces extrusion of live cells to control epithelial cell numbers. Extrusion of live cells occurs at sites where the highest crowding occurs in vivo and can be induced by experimentally overcrowding monolayers in vitro. Like apoptotic cell extrusion, live cell extrusion resulting from overcrowding also requires sphingosine 1-phosphate signalling and Rho-kinase-dependent myosin contraction, but is distinguished by signalling through stretch-activated channels. Moreover, disruption of a stretch-activated channel, Piezo1, in zebrafish prevents extrusion and leads to the formation of epithelial cell masses. Our findings reveal that during homeostatic turnover, growth and division of epithelial cells on a confined substratum cause overcrowding that leads to their extrusion and consequent death owing to the loss of survival factors. These results suggest that live cell extrusion could be a tumour-suppressive mechanism that prevents the accumulation of excess epithelial cells.

Margination of white blood cells in microcapillary flow.

Margination of white blood cells (WBCs) towards vessel walls is an essential precondition for their efficient adhesion to the vascular endothelium. We perform numerical simulations with a two-dimensional blood flow model to investigate the dependence of WBC margination on hydrodynamic interactions of blood cells with the vessel walls, as well as on their collective behavior and deformability. We find WBC margination to be optimal in intermediate ranges of red blood cell (RBC) volume fractions and flow rates, while, beyond these ranges, it is substantially attenuated. RBC aggregation enhances WBC margination, while WBC deformability reduces it. These results are combined in state diagrams, which identify WBC margination for a wide range of flow and cell suspension conditions.

Human NK cells in acute myeloid leukaemia patients: analysis of NK cell-activating receptors and their ligands

Natural killer (NK) cell activation is strictly regulated to ensure that healthy cells are preserved, but tumour-transformed or virus-infected cells are recognized and eliminated. To carry out this selective killing, NK cells have an ample repertoire of receptors on their surface. Signalling by inhibitory and activating receptors by interaction with their ligands will determine whether the NK cell becomes activated and kills the target cell. Here, we show reduced expression of NKp46, NKp30, DNAM-1, CD244 and CD94/NKG2C activating receptors on NK cells from acute myeloid leukaemia patients. This reduction may be induced by chronic exposure to their ligands on leukaemic blasts. The analysis of ligands for NK cell-activating receptors showed that leukaemic blasts from the majority of patients express ligands for NK cell-activating receptors. DNAM-1 ligands are frequently expressed on blasts, whereas the expression of the NKG2D ligand MICA/B is found in half of the patients and CD48, a ligand for CD244, in only one-fourth of the patients. The decreased expression of NK cell-activating receptors and/or the heterogeneous expression of ligands for major receptors on leukaemic blasts can lead to an inadequate tumour immunosurveillance by NK cells. A better knowledge of the activating receptor repertoire on NK cells and their putative ligands on blasts together with the possibility to modulate their expression will open new possibilities for the use of NK cells in immunotherapy against leukaemia.

Chronic Hepatitis B Infection: A Review

Importance More than 240 million individuals worldwide are infected with chronic hepatitis B virus (HBV). Among individuals with chronic HBV infection who are untreated, 15% to 40% progress to cirrhosis, which may lead to liver failure and liver cancer. Observations Pegylated interferon and nucleos(t)ide analogues (lamivudine, adefovir, entecavir, tenofovir disoproxil, and tenofovir alafenamide) suppress HBV DNA replication and improve liver inflammation and fibrosis. Long-term viral suppression is associated with regression of liver fibrosis and reduced risk of hepatocellular carcinoma in cohort studies. The cure (defined as hepatitis B surface antigen loss with undetectable HBV DNA) rates after treatment remain low (3%-7% with pegylated interferon and 1%-12% with nucleos[t]ide analogue therapy). Pegylated interferon therapy can be completed in 48 weeks and is not associated with the development of resistance; however, its use is limited by poor tolerability and adverse effects such as bone marrow suppression and exacerbation of existing neuropsychiatric symptoms such as depression. Newer agents (entecavir, tenofovir disoproxil, and tenofovir alafenamide) may be associated with a significantly reduced risk of drug resistance compared with older agents (lamivudine and adefovir) and should be considered as the first-line treatment. Conclusions and Relevance Antiviral treatment with either pegylated interferon or a nucleos(t)ide analogue (lamivudine, adefovir, entecavir, tenofovir disoproxil, or tenofovir alafenamide) should be offered to patients with chronic HBV infection and liver inflammation in an effort to reduce progression of liver disease. Nucleos(t)ide analogues should be considered as first-line therapy. Because cure rates are low, most patients will require therapy indefinitely.

An overview of the effective combination therapies for the treatment of breast cancer.

Breast cancer (BC) is generally classified based on the receptors overexpressed on the cell nucleus, which include hormone receptors such as progesterone (PR) and estrogen (ER), and HER2. Triple-negative breast cancer (TNBC) is a type of cancer that lacks any of these three types of receptor proteins (ER/PR/HER2). Tumor cells exhibit drug resistant phenotypes that decrease the efficacy of chemotherapeutic treatments. Generally, drug resistance has a genetic basis that is caused by an abnormal gene expression, nevertheless, there are several types of drug resistance: efflux pumps reducing the cellular concentration of the drug, alterations in membrane lipids that reduce cellular uptake, increased or altered drug targets, metabolic alteration of the drug, inhibition of apoptosis, repair of the damaged DNA, and alteration of the cell cycle checkpoints. The use of "combination therapy" is recognized as an efficient solution to treat human diseases, in particular, breast cancer. In this review, we give examples of different nanocarriers used to co-deliver multiple therapeutics (chemotherapeutic agent and nucleic acid) to drug-resistant tumor cells, and lastly, we give our recommendations for the future directions for the co-delivery treatments.

Summary

The genetic diseases Hutchinson-Gilford progeria syndrome (HGPS) and restrictive dermopathy (RD) arise from accumulation of farnesylated prelamin A because of defects in the lamin A maturation pathway. Both of these diseases exhibit symptoms that can be viewed as accelerated aging. The mechanism by which accumulation of farnesylated prelamin A leads to these accelerated aging phenotypes is not understood. Here we present evidence that in HGPS and RD fibroblasts, DNA damage checkpoints are persistently activated because of the compromise in genomic integrity. Inactivation of checkpoint kinases Ataxia-telangiectasia-mutated (ATM) and ATR (ATM- and Rad3-related) in these patient cells can partially overcome their early replication arrest. Treatment of patient cells with a protein farnesyltransferase inhibitor (FTI) did not result in reduction of DNA double-strand breaks and damage checkpoint signaling, although the treatment significantly reversed the aberrant shape of their nuclei. This suggests that DNA damage accumulation and aberrant nuclear morphology are independent phenotypes arising from prelamin A accumulation in these progeroid syndromes. Since DNA damage accumulation is an important contributor to the symptoms of HGPS, our results call into question the possibility of treatment of HGPS with FTIs alone.

A role for fibroblasts in mediating the effects of tobacco-induced epithelial cell growth and invasion.

Cigarette smoke and smokeless tobacco extracts contain multiple carcinogenic compounds, but little is known about the mechanisms by which tumors develop and progress upon chronic exposure to carcinogens such as those present in tobacco products. Here, we examine the effects of smokeless tobacco extracts on human oral fibroblasts. We show that smokeless tobacco extracts elevated the levels of intracellular reactive oxygen, oxidative DNA damage, and DNA double-strand breaks in a dose-dependent manner. Extended exposure to extracts induced fibroblasts to undergo a senescence-like growth arrest, with striking accompanying changes in the secretory phenotype. Using cocultures of smokeless tobacco extracts-exposed fibroblasts and immortalized but nontumorigenic keratinocytes, we further show that factors secreted by extracts-modified fibroblasts increase the proliferation and invasiveness of partially transformed epithelial cells, but not their normal counterparts. In addition, smokeless tobacco extracts-exposed fibroblasts caused partially transformed keratinocytes to lose the expression of E-cadherin and ZO-1, as well as involucrin, changes that are indicative of compromised epithelial function and commonly associated with malignant progression. Together, our results suggest that fibroblasts may contribute to tumorigenesis indirectly by increasing epithelial cell aggressiveness. Thus, tobacco may not only initiate mutagenic changes in epithelial cells but also promote the growth and invasion of mutant cells by creating a procarcinogenic stromal environment.

Anti-alphav integrin monoclonal antibody intetumumab enhances the efficacy of radiation therapy and reduces metastasis of human cancer xenografts in nude rats.

We previously reported that intetumumab (CNTO 95), a fully human anti-αv integrin monoclonal antibody, is a radiosensitizer in mice with xenograft tumors. Because intetumumab does not cross-react with mouse integrins, but has cross-reactivity with rat integrins, we next studied the potential combined use of radiation therapy and intetumumab in human cancer xenograft models in nude rats to assess effects on both tumor cells and the tumor microenvironment. Nude rats bearing human head and neck cancer and non-small cell lung cancer (NSCLC) xenografts were treated with intetumumab and fractionated local tumor radiotherapy. Effects on tumor growth and metastasis, blood perfusion, oxygenation, and gastrointestinal toxicity were studied. Intetumumab alone had a moderate effect on tumor growth. When combined with fractionated radiation therapy, intetumumab significantly inhibited tumor growth and produced a tumor response rate that was significantly better than with radiation therapy alone. Treatment with intetumumab also significantly reduced lung metastasis in the A549 NSCLC xenograft model. The oxygenation and blood perfusion in xenograft tumors measured by microbubble-enhanced ultrasound imaging were substantially increased after treatment with intetumumab. The combined use of intetumumab and radiation therapy reduced the microvessel density and increased apoptosis in tumor cells and the tumor microenvironment. Toxicity studies showed that treatment with intetumumab did not cause the histopathologic changes in the lungs and did not sensitize the sensitive gastrointestinal epithelium to the effect of radiation therapy. Intetumumab can potentiate the efficacy of fractionated radiation therapy in human cancer xenograft tumors in nude rats without increased toxicity.

Glioblastomas are deadly cancers that display a functional cellular hierarchy maintained by self-renewing glioblastoma stem cells (GSCs). GSCs are regulated by molecular pathways distinct from the bulk tumor that may be useful therapeutic targets. We determined that A20 (TNFAIP3), a regulator of cell survival and the NF-kappaB pathway, is overexpressed in GSCs relative to non-stem glioblastoma cells at both the mRNA and protein levels. To determine the functional significance of A20 in GSCs, we targeted A20 expression with lentiviral-mediated delivery of short hairpin RNA (shRNA). Inhibiting A20 expression decreased GSC growth and survival through mechanisms associated with decreased cell-cycle progression and decreased phosphorylation of p65/RelA. Elevated levels of A20 in GSCs contributed to apoptotic resistance: GSCs were less susceptible to TNFalpha-induced cell death than matched non-stem glioma cells, but A20 knockdown sensitized GSCs to TNFalpha-mediated apoptosis. The decreased survival of GSCs upon A20 knockdown contributed to the reduced ability of these cells to self-renew in primary and secondary neurosphere formation assays. The tumorigenic potential of GSCs was decreased with A20 targeting, resulting in increased survival of mice bearing human glioma xenografts. In silico analysis of a glioma patient genomic database indicates that A20 overexpression and amplification is inversely correlated with survival. Together these data indicate that A20 contributes to glioma maintenance through effects on the glioma stem cell subpopulation. Although inactivating mutations in A20 in lymphoma suggest A20 can act as a tumor suppressor, similar point mutations have not been identified through glioma genomic sequencing: in fact, our data suggest A20 may function as a tumor enhancer in glioma through promotion of GSC survival. A20 anticancer therapies should therefore be viewed with caution as effects will likely differ depending on the tumor type.

Inhibition of Hedgehog signaling enhances delivery of chemotherapy in a mouse model of pancreatic cancer.

Pancreatic ductal adenocarcinoma (PDA) is among the most lethal human cancers in part because it is insensitive to many chemotherapeutic drugs. Studying a mouse model of PDA that is refractory to the clinically used drug gemcitabine, we found that the tumors in this model were poorly perfused and poorly vascularized, properties that are shared with human PDA. We tested whether the delivery and efficacy of gemcitabine in the mice could be improved by coadministration of IPI-926, a drug that depletes tumor-associated stromal tissue by inhibition of the Hedgehog cellular signaling pathway. The combination therapy produced a transient increase in intratumoral vascular density and intratumoral concentration of gemcitabine, leading to transient stabilization of disease. Thus, inefficient drug delivery may be an important contributor to chemoresistance in pancreatic cancer.

miR-205 hinders the malignant interplay between prostate cancer cells and associated fibroblasts.

AIMS Tumor microenvironment is a strong determinant for the acquisition of metastatic potential of cancer cells. We have recently demonstrated that cancer-associated fibroblasts (CAFs) elicit a redox-dependent epithelial-mesenchymal transition (EMT) in prostate cancer (PCa) cells, driven by cycloxygenase-2/hypoxia-inducible factor-1 (HIF-1)/nuclear factor-κB pathway and enhancing tumor aggressiveness. Here, we investigated the involvement of microRNAs (miRNAs) in tumor-stroma interplay to identify possible tools to counteract oxidative stress and metastasis dissemination. RESULTS We found that miR-205 is the most downmodulated miRNA in PCa cells upon CAF stimulation, due to direct transcriptional repression by HIF-1, a known redox-sensitive transcription factor. Rescue experiments demonstrated that ectopic miR-205 overexpression in PCa cells counteracts CAF-induced EMT, thus impairing enhancement of cell invasion, acquisition of stem cell traits, tumorigenicity, and metastatic dissemination. In addition, miR-205 blocks tumor-driven activation of surrounding fibroblasts by reducing pro-inflammatory cytokine secretion. INNOVATION Overall, such findings suggest miR-205 as a brake against PCa metastasis by blocking both the afferent and efferent arms of the circuit between tumor cells and associated fibroblasts, thus interrupting the pro-oxidant and pro-inflammatory circuitries engaged by reactive stroma. CONCLUSION The evidence that miR-205 replacement in PCa cells is able not only to prevent but also to revert the oxidative/pro-inflammatory axis leading to EMT induced by CAFs sets the rationale for developing miRNA-based approaches to prevent and treat metastatic disease.

Influence of DNA on the activities and inhibition of neutrophil serine proteases in cystic fibrosis sputum.

Uncontrolled proteolysis by neutrophil serine proteases (NSPs) in lung secretions is a hallmark of cystic fibrosis (CF). We have shown that the active neutrophil elastase, protease 3, and cathepsin G in CF sputum resist inhibition in part by exogenous protease inhibitors. This resistance may be due to their binding to neutrophil extracellular traps (NETs) secreted by the activated neutrophils in CF sputum and to genomic DNA released from senescent and dead neutrophils. Treating CF sputum with DNase dramatically increases its elastase activity, which can then be stoichiometrically inhibited by exogenous elastase inhibitors. However, DNase treatment does not increase the activities of protease 3 and cathepsin G, indicating their different distribution and/or binding in CF sputum. Purified blood neutrophils secrete NETs when stimulated by the opportunistic CF bacteria Pseudomonas aeruginosa and Staphylococcus aureus. The activities of the three proteases were unchanged in these conditions, but subsequent DNase treatment produced a dramatic increase in all three proteolytic activities. Neutrophils activated with a calcium ionophore did not secrete NETs but released huge amounts of active proteases whose activities were not modified by DNase. We conclude that NETs are reservoirs of active proteases that protect them from inhibition and maintain them in a rapidly mobilizable status. Combining the effects of protease inhibitors with that of DNA-degrading agents could counter the deleterious proteolytic effects of NSPs in CF lung secretions.

Angiopoietin-like protein 3 supports the activity of hematopoietic stem cells in the bone marrow niche.

The physiologic roles of angiopoietin-like proteins (Angptls) in the hematopoietic system remain unknown. Here we show that hematopoietic stem cells (HSCs) in Angptl3-null mice are decreased in number and quiescence. HSCs transplanted into Angptl3-null recipient mice exhibited impaired repopulation. Bone marrow sinusoidal endothelial cells express high levels of Angptl3 and are adjacent to HSCs. Importantly, bone marrow stromal cells or endothelium deficient in Angptl3 have a significantly decreased ability to support the expansion of repopulating HSCs. Angptl3 represses the expression of the transcription factor Ikaros, whose unregulated overexpression diminishes the repopulation activity of HSCs. Angptl3, as an extrinsic factor, thus supports the stemness of HSCs in the bone marrow niche.

mir-1-mediated paracrine effect of cancer-associated fibroblasts on lung cancer cell proliferation and chemoresistance.

Lung cancer is the leading cause of cancer-related mortality in humans worldwide. Moreover, the overall 5-year survival rate is only 15%. Pathologically almost 80% of all lung cancer cases are non-small cell lung cancer (NSCLC). Cancer-associated fibroblasts (CAFs) have been found to exist in a large number of NSCLCs. CAFs have been proven to promote tumor progression, metastasis and resistance to therapy through paracrine effects in most solid tumors. In the present study, firstly we isolated CAFs from patient tissues and demonstrated that they promoted cell proliferation and chemoresistance to cisplatin in the lung cancer cell lines A549 and 95D in a paracrine manner. Secondly, using ELISA and quantative PCR, we found that a higher amount of stromal cell-derived factor 1 (SDF-1) existed in the CAFs rather than that observed in the normal fibroblasts (NFs). Thirdly, we detected that SDF-1 facilitated lung cancer cell proliferation and drug resistance via the CXCR4-mediated signaling pathway which involved NF-κB and Bcl-xL. Moreover, we also confirmed that the expression level of SDF-1 in the CAFs was negatively regulated by microRNA mir-1 through microRNA overexpression and quantitative PCR. Overall, our data provide one explanation for the effects of CAFs on lung cancer cells. Meanwhile, our results also suggest CAFs as a potential therapeutic target in tumor treatment.

Pharmacological correction of a defect in PPARγ signaling ameliorates disease severity in Cftr-deficient mice

Cystic fibrosis is caused by mutations in the cystic fibrosis transmembrane conductance regulator (encoded by Cftr) that impair its role as an apical chloride channel that supports bicarbonate transport. Individuals with cystic fibrosis show retained, thickened mucus that plugs airways and obstructs luminal organs as well as numerous other abnormalities that include inflammation of affected organs, alterations in lipid metabolism and insulin resistance. Here we show that colonic epithelial cells and whole lung tissue from Cftr-deficient mice show a defect in peroxisome proliferator-activated receptor-gamma (PPAR-gamma, encoded by Pparg) function that contributes to a pathological program of gene expression. Lipidomic analysis of colonic epithelial cells suggests that this defect results in part from reduced amounts of the endogenous PPAR-gamma ligand 15-keto-prostaglandin E(2) (15-keto-PGE(2)). Treatment of Cftr-deficient mice with the synthetic PPAR-gamma ligand rosiglitazone partially normalizes the altered gene expression pattern associated with Cftr deficiency and reduces disease severity. Rosiglitazone has no effect on chloride secretion in the colon, but it increases expression of the genes encoding carbonic anhydrases 4 and 2 (Car4 and Car2), increases bicarbonate secretion and reduces mucus retention. These studies reveal a reversible defect in PPAR-gamma signaling in Cftr-deficient cells that can be pharmacologically corrected to ameliorate the severity of the cystic fibrosis phenotype in mice.

Tamoxifen resistance in MCF7 cells promotes EMT-like behaviour and involves modulation of beta-catenin phosphorylation.

We have previously demonstrated that, following acquisition of endocrine resistance, breast cancer cells display an altered growth rate together with increased aggressive behaviour in vitro. Since dysfunctional cell-cell adhesive interactions can promote an aggressive phenotype, we investigated the integrity of this protein complex in our breast cancer model of tamoxifen resistance. In culture, tamoxifen-resistant MCF7 (TamR) cells grew as loosely packed colonies with loss of cell-cell junctions and demonstrated altered morphology characteristic of cells undergoing epithelial-to-mesenchymal transition (EMT). Neutralising E-cadherin function promoted the invasion and inhibited the aggregation of endocrine-sensitive MCF7 cells, whilst having little effect on the behaviour of TamR cells. Additionally, TamR cells had increased levels of tyrosine-phosphorylated beta-catenin, whilst serine/threonine-phosphorylated beta-catenin was decreased. These cells also displayed loss of association between beta-catenin and E-cadherin, increased cytoplasmic and nuclear beta-catenin and elevated transcription of beta-catenin target genes known to be involved in tumour progression and EMT. Inhibition of EGFR kinase activity in TamR cells reduced beta-catenin tyrosine phosphorylation, increased beta-catenin-E-cadherin association and promoted cell-cell adhesion. In such treated cells, the association of beta-catenin with Lef-1 and the transcription of c-myc, cyclin-D1, CD44 and COX-2 were also reduced. These results suggest that homotypic adhesion in tamoxifen-resistant breast cancer cells is dysfunctional due to EGFR-driven modulation of the phosphorylation status of beta-catenin and may contribute to an enhanced aggressive phenotype and transition towards a mesenchymal phenotype in vitro.

Intrinsic genetic characteristics determine tumor-modifying capacity of fibroblasts: matrix metalloproteinase-3 5A/5A genotype enhances breast cancer cell invasion

Stromal fibroblasts can contribute to tumor invasion through the release of matrix metalloproteinases (MMPs). Population studies have suggested that single nucleotide polymorphisms (SNPs) in MMP genes influence levels of expression and may be associated with breast cancer risk and with disease progression. This study directly examined the impact of MMP SNP genotype on the ability of host fibroblasts to promote tumor cell invasion. Primary breast fibroblasts were isolated from patients with (n = 13) or without (n = 19) breast cancer, and their ability to promote breast cancer cell invasion was measured in in vitro invasion assays. Fibroblast invasion-promoting capacity (IPC) was analyzed in relation to donor type (tumor or non-tumor patient), MMP-1, MMP-3, and MMP-9 SNP genotype and MMP activity using independent samples t test and analysis of variance. All statistical tests were two-sided. Tumor-derived fibroblasts promoted higher levels of invasion than normal fibroblasts (p = 0.041). When IPC was related to genotype, higher levels of IPC were generated by tumor fibroblasts with the high-expressing MMP-3 5A/5A genotype compared with the 5A/6A and 6A/6A genotypes (p = 0.05 and 0.07, respectively), and this was associated with enhanced MMP-3 release. The functional importance of MMP-3 was demonstrated by enhanced invasion in the presence of recombinant MMP-3, whereas reduction occurred in the presence of a specific MMP-3 inhibitor. An inverse relationship was demonstrated between fibroblast IPC and the high-expressing MMP-1 genotype (p = 0.031), but no relationship was seen with MMP-9 SNP status. In contrast, normal fibroblasts showed no variation in IPC in relation to MMP genotype, with MMP-3 5A/5A fibroblasts exhibiting significantly lower levels of IPC than their tumor-derived counterparts (p = 0.04). This study has shown that tumor-derived fibroblasts exhibit higher levels of IPC than normal fibroblasts and that the MMP-3 5A/5A genotype contributes to this through enhanced MMP-3 release. Despite a high-expressing genotype, normal fibroblasts do not exhibit higher IPC or enhanced MMP release. This suggests that more complex changes occur in tumor-derived fibroblasts, enabling full expression of the MMP SNP genotype and these possibly are epigenetic in nature. The results do suggest that, in women with breast cancer, a high-expressing MMP-3 genotype may promote tumor progression more effectively.

Dendritic cells, T cells and lymphatics: dialogues in migration and beyond.

Immune cells continuously recirculate through lymph vessels en route from peripheral tissues to the blood. Leuyte trafficking into and within lymph vessels is mediated by an interply with lymphatic endothelial cells (LECs). However, lymphatic vessels are much more than mere conduits for fluid and immune cell transport. Data accumulating during past several years indicate that LECs support T cell survival, induce tolerance to self-antigens, inhibit exaggerated T cell proliferation during immune response and maintain T cell memory. Reciprocally, leukocytes impact LEC biology: lymphatic vessel permeability depends on DCs while lymphocytes regulate LEC proliferation during inflammation. Altogether, these novel results provide important insights on intimate connections between LECs and leukocytes that contribute to the understanding of immune responses.

Endothelial-to-mesenchymal transition contributes to cardiac fibrosis

Cardiac fibrosis, associated with a decreased extent of microvasculature and with disruption of normal myocardial structures, results from excessive deposition of extracellular matrix, which is mediated by the recruitment of fibroblasts. The source of these fibroblasts is unclear and specific anti-fibrotic therapies are not currently available. Here we show that cardiac fibrosis is associated with the emergence of fibroblasts originating from endothelial cells, suggesting an endothelial-mesenchymal transition (EndMT) similar to events that occur during formation of the atrioventricular cushion in the embryonic heart. Transforming growth factor-β1 (TGF-β1) induced endothelial cells to undergo EndMT, whereas bone morphogenic protein 7 (BMP-7) preserved the endothelial phenotype. The systemic administration of recombinant human BMP-7 (rhBMP-7) significantly inhibited EndMT and the progression of cardiac fibrosis in mouse models of pressure overload and chronic allograft rejection. Our findings show that EndMT contributes to the progression of cardiac fibrosis and that rhBMP-7 can be used to inhibit EndMT and to intervene in the progression of chronic heart disease associated with fibrosis.

Incidence of cancer after immunosuppressive treatment for heart transplantation.

Prolonged or intensive immunosuppressive therapy used after organ transplantation is complicated by an increased incidence of cancer. Striking differences in incidence are observed in heart and heart-lung transplant recipients when compared with renal transplant patients. The most significant increase was in the incidence of lymphomas in cardiac versus renal patients. Moreover, a two-fold greater increase of all neoplasms was found in cardiac recipients, with nearly a six-fold increase in visceral tumors. Several factors may account for these differences. In cardiac allograft recipients, intensive immunosuppression is frequently used to reverse acute rejection and the highest number of cardiac transplants was performed in the era of polypharmacy, usually consisting of triple therapy.

Gr-1+CD11b+ myeloid cells tip the balance of immune protection to tumor promotion in the premetastatic lung.

The mechanisms by which a primary tumor affects a selected distant organ before tumor cell arrival remain to be elucidated. This report shows that Gr-1+CD11b+ cells are significantly increased in lungs of mice bearing mammary adenocarcinomas before tumor cell arrival. In the premetastatic lungs, these immature myeloid cells significantly decrease IFN-gamma production and increase proinflammatory cytokines. In addition, they produce large quantities of matrix metalloproteinase 9 (MMP9) and promote vascular remodeling. Deletion of MMP9 normalizes aberrant vasculature in the premetastatic lung and diminishes lung metastasis. The production and activity of MMP9 is selectively restricted to lungs and organs with a large number of Gr-1+CD11b+ cells. Our work reveals a novel protumor mechanism for Gr-1+CD11b+ cells that changes the premetastatic lung into an inflammatory and proliferative environment, diminishes immune protection, and promotes metastasis through aberrant vasculature formation. Thus, inhibition of Gr-1+CD11b+ cells could normalize the premetastatic lung environment, improve host immunosurveillance, and inhibit tumor metastasis.

Discovery of endothelial to mesenchymal transition as a source for carcinoma-associated fibroblasts.

Activated fibroblasts are associated with many different tumors. Myofibroblasts, activated fibroblasts, and perivascular mesenchymal cells such as pericytes play a role in cancer progression. Many studies suggest that myofibroblasts facilitate tumor growth and cancer progression. The source for myofibroblasts and other activated fibroblasts within the tumors is still debated. Although de novo activation of quiescent fibroblasts into alpha-smooth muscle actin (alpha SMA)-positive myofibroblasts is one likely source, epithelial to mesenchymal transition and bone marrow recruitment are also evolving as possible mechanisms for the emergence of a heterogeneous population of carcinoma-associated fibroblasts. Here, we show that transforming growth factor-beta1 could induce proliferating endothelial cells to undergo a phenotypic conversion into fibroblast-like cells. Such endothelial to mesenchymal transition (EndMT) is associated with the emergence of mesenchymal marker fibroblast-specific protein-1 (FSP1) and down-regulation of CD31/PECAM. Additionally, we show EndMT in tumors using the B16F10 melanoma model and the Rip-Tag2 spontaneous pancreatic carcinoma model. Crossing Tie2-Cre mice with R26Rosa-lox-Stop-lox-LacZ mice allows for irreversible tagging of endothelial cells. We provide unequivocal evidence for EndMT at the invasive front of the tumors in these transgenic mice. Collectively, our results show that EndMT is a unique mechanism for the accumulation of carcinoma-associated fibroblasts and suggest that antiangiogenic treatment of tumors may have a direct effect in decreasing activated fibroblasts that likely facilitate cancer progression.

PDGF-BB secreted by preosteoclasts induces angiogenesis during coupling with osteogenesis

Osteogenesis during bone modeling and remodeling is coupled with angiogenesis. A recent study showed that a specific vessel subtype, strongly positive for CD31 and endomucin (CD31hiEmcnhi), couples angiogenesis and osteogenesis. Here, we found that platelet-derived growth factor-BB (PDGF-BB) secreted by preosteoclasts induces CD31hiEmcnhi vessel formation during bone modeling and remodeling. Mice with depletion of PDGF-BB in the tartrate-resistant acid phosphatase–positive cell lineage show significantly lower trabecular and cortical bone mass, serum and bone marrow PDGF-BB concentrations, and fewer CD31hiEmcnhi vessels compared to wild-type mice. In the ovariectomy (OVX)-induced osteoporotic mouse model, serum and bone marrow levels of PDGF-BB and numbers of CD31hiEmcnhi vessels are significantly lower compared to sham-operated controls. Treatment with exogenous PDGF-BB or inhibition of cathepsin K to increase the number of preosteoclasts, and thus the endogenous levels of PDGF-BB, increases CD31hiEmcnhi vessel number and stimulates bone formation in OVX mice. Thus, pharmacotherapies that increase PDGF-BB secretion from preosteoclasts offer a new therapeutic target for treating osteoporosis by promoting angiogenesis and thus bone formation.

IL-18 induction of osteopontin mediates cardiac fibrosis and diastolic dysfunction in mice.

Osteopontin (OPN), a key component of the extracellular matrix, is associated with the fibrotic process during tissue remodeling. OPN and the cytokine interleukin (IL)-18 have been shown to be overexpressed in an array of human cardiac pathologies. In the present study, we determined the role of IL-18 in the regulation of cardiac OPN expression and the subsequent interstitial fibrosis and diastolic dysfunction. We demonstrated parallel increases in IL-18, OPN expression, and interstitial fibrosis in murine models of left ventricular pressure and volume overload. Exogenous recombinant (r)IL-18 administered for 2 wk increased cardiac OPN expression, interstitial fibrosis, and diastolic dysfunction. Stimulation of the T helper (Th)1 lymphocyte phenotype with a selective toll-like receptor (TLR)9 agonist induced cardiac IL-18 and OPN expression, which was associated with increased cardiac fibrillar collagen concentrations and interstitial fibrosis resulting in diastolic dysfunction. rIL-18 induced OPN expression and protein levels in primary of cardiac fibroblast cultures. Conditioned media from TLR9-stimulated T lymphocyte cultures induced IL-18 and OPN expression in cardiac fibroblasts, while blockade of the IL-18 receptor with a neutralizing antibody abolished the increase in OPN expression. Furthermore, a mutation in the transcriptional factor interferon regulatory factor (IRF)1 or IRF1 small interfering RNA (siRNA) resulted in the decreased expression of IL-18 and OPN in cardiac fibroblasts. With pressure overload, IRF1-mutant mice showed downregulation of IL-18 and OPN expression in cardiac tissue, reduced cardiac fibrotic development, and increased left ventricular function compared with wild type. These results provide direct evidence that the induction of IL-18 regulates OPN-mediated cardiac fibrosis and diastolic dysfunction.

American Society of Clinical Oncology policy statement: the role of the oncologist in cancer prevention and risk assessment.

Oncologists have a critical opportunity to utilize risk assessment and cancer prevention strategies to interrupt the initiation or progression of cancer in cancer survivors and individuals at high risk of developing cancer. Expanding knowledge about the natural history and prognosis of cancers positions oncologists to advise patients regarding the risk of second malignancies and treatment-related cancers. In addition, as recognized experts in the full spectrum of cancer care, oncologists are afforded opportunities for involvement in community-based cancer prevention activities. Although oncologists are currently providing many cancer prevention and risk assessment services to their patients, economic barriers exist, including inadequate or lack of insurance, that may compromise uniform patient access to these services. Additionally, insufficient reimbursement for existing and developing interventions may discourage patient access to these services. The American Society of Clinical Oncology (ASCO), the medical society representing cancer specialists involved in patient care and clinical research, is committed to supporting oncologists in their wide-ranging involvement in cancer prevention. This statement on risk assessment and prevention counseling, although not intended to be a comprehensive overview of cancer prevention describes the current role of oncologists in risk assessment and prevention; provides examples of risk assessment and prevention activities that should be offered by oncologists; identifies potential opportunities for coordination between oncologists and primary care physicians in prevention education and coordination of care for cancer survivors; describes ASCO's involvement in education and training of oncologists regarding prevention; and proposes improvement in the payment environment to encourage patient access to these services.

Role of the vascular endothelial growth factor pathway in tumor growth and angiogenesis.

New blood vessel formation (angiogenesis) is a fundamental event in the process of tumor growth and metastatic dissemination. Hence, the molecular basis of tumor angiogenesis has been of keen interest in the field of cancer research. The vascular endothelial growth factor (VEGF) pathway is well established as one of the key regulators of this process. The VEGF/VEGF-receptor axis is composed of multiple ligands and receptors with overlapping and distinct ligand-receptor binding specificities, cell-type expression, and function. Activation of the VEGF-receptor pathway triggers a network of signaling processes that promote endothelial cell growth, migration, and survival from pre-existing vasculature. In addition, VEGF mediates vessel permeability, and has been associated with malignant effusions. More recently, an important role for VEGF has emerged in mobilization of endothelial progenitor cells from the bone marrow to distant sites of neovascularization. The well-established role of VEGF in promoting tumor angiogenesis and the pathogenesis of human cancers has led to the rational design and development of agents that selectively target this pathway. Studies with various anti-VEGF/VEGF-receptor therapies have shown that these agents can potently inhibit angiogenesis and tumor growth in preclinical models. Recently, an anti-VEGF antibody (bevacizumab), when used in combination with chemotherapy, was shown to significantly improve survival and response rates in patients with metastatic colorectal cancer and thus, validate VEGF pathway inhibitors as an important new treatment modality in cancer therapy.

Specific killing of multiple myeloma cells by (-)-epigallocatechin-3-gallate extracted from green tea: biologic activity and therapeutic implications.

Epigallocatechin-3-gallate (EGCG), a polyphenol extracted from green tea, is an antioxidant with chemopreventive and chemotherapeutic actions. Based on its ability to modulate growth factor-mediated cell proliferation, we evaluated its efficacy in multiple myeloma (MM). EGCG induced both dose- and time-dependent growth arrest and subsequent apoptotic cell death in MM cell lines including IL-6-dependent cells and primary patient cells, without significant effect on the growth of peripheral blood mononuclear cells (PBMCs) and normal fibroblasts. Treatment with EGCG also led to significant apoptosis in human myeloma cells grown as tumors in SCID mice. EGCG interacts with the 67-kDa laminin receptor 1 (LR1), which is significantly elevated in myeloma cell lines and patient samples relative to normal PBMCs. RNAi-mediated inhibition of LR1 resulted in abrogation of EGCG-induced apoptosis in myeloma cells, indicating that LR1 plays an important role in mediating EGCG activity in MM while sparing PBMCs. Evaluation of changes in gene expression profile indicates that EGCG treatment activates distinct pathways of growth arrest and apoptosis in MM cells by inducing the expression of death-associated protein kinase 2, the initiators and mediators of death receptor-dependent apoptosis (Fas ligand, Fas, and caspase 4), p53-like proteins (p73, p63), positive regulators of apoptosis and NF-kappaB activation (CARD10, CARD14), and cyclin-dependent kinase inhibitors (p16 and p18). Expression of related genes at the protein level were also confirmed by Western blot analysis. These data demonstrate potent and specific antimyeloma activity of EGCG and provide the rationale for its clinical evaluation.

Inhibition of fatty acid oxidation modulates immunosuppressive functions of myeloid-derived suppressor cells and enhances cancer therapies

Myeloid-derived suppressor cells (MDSC) promote tumor growth by inhibiting T-cell immunity and promoting malignant cell proliferation and migration. The therapeutic potential of blocking MDSC in tumors has been limited by their heterogeneity, plasticity, and resistance to various chemotherapy agents. Recent studies have highlighted the role of energy metabolic pathways in the differentiation and function of immune cells; however, the metabolic characteristics regulating MDSC remain unclear. We aimed to determine the energy metabolic pathway(s) used by MDSC, establish its impact on their immunosuppressive function, and test whether its inhibition blocks MDSC and enhances antitumor therapies. Using several murine tumor models, we found that tumor-infiltrating MDSC (T-MDSC) increased fatty acid uptake and activated fatty acid oxidation (FAO). This was accompanied by an increased mitochondrial mass, upregulation of key FAO enzymes, and increased oxygen consumption rate. Pharmacologic inhibition of FAO blocked immune inhibitory pathways and functions in T-MDSC and decreased their production of inhibitory cytokines. FAO inhibition alone significantly delayed tumor growth in a T-cell-dependent manner and enhanced the antitumor effect of adoptive T-cell therapy. Furthermore, FAO inhibition combined with low-dose chemotherapy completely inhibited T-MDSC immunosuppressive effects and induced a significant antitumor effect. Interestingly, a similar increase in fatty acid uptake and expression of FAO-related enzymes was found in human MDSC in peripheral blood and tumors. These results support the possibility of testing FAO inhibition as a novel approach to block MDSC and enhance various cancer therapies.

Microenvironment rigidity modulates responses to the HER2 receptor tyrosine kinase inhibitor lapatinib via YAP and TAZ transcription factors.

Stiffness is a biophysical property of the extracellular matrix that modulates cellular functions, including proliferation, invasion, and differentiation, and it also may affect therapeutic responses. Therapeutic durability in cancer treatments remains a problem for both chemotherapies and pathway-targeted drugs, but the reasons for this are not well understood. Tumor progression is accompanied by changes in the biophysical properties of the tissue, and we asked whether matrix rigidity modulated the sensitive versus resistant states in HER2-amplified breast cancer cell responses to the HER2-targeted kinase inhibitor lapatinib. The antiproliferative effect of lapatinib was inversely proportional to the elastic modulus of the adhesive substrata. Down-regulation of the mechanosensitive transcription coactivators YAP and TAZ, either by siRNA or with the small-molecule YAP/TEAD inhibitor verteporfin, eliminated modulus-dependent lapatinib resistance. Reduction of YAP in vivo in mice also slowed the growth of implanted HER2-amplified tumors, showing a trend of increasing sensitivity to lapatinib as YAP decreased. Thus we address the role of stiffness in resistance to and efficacy of a HER2 pathway-targeted therapeutic via the mechanotransduction arm of the Hippo pathway.

Angiogenesis therapy: amidst the hype, the neglected potential for serious side effects.

Although essentially unknown as a therapeutic concept as recently as a decade ago, it is difficult now to open a cardiology journal, attend a cardiology meeting, or scan a newspaper without being caught up in the excitement generated by the thought that angiogenesis therapy may soon have a major impact on the treatment of patients with atherosclerotic lesions obstructing arteries that supply the myocardium or legs. Potent therapeutic interventions, however, are rarely free of at least the potential for causing harmful effects. Angiogenesis therapy is no exception. Despite this and despite the fact that the only reasonably powered, randomized, double-blind clinical studies to date have failed to demonstrate primary end-point efficacy,1 thoughtful consideration of the serious side effects that might accompany any therapeutic benefit has been largely missing from scientific communications. For the lay media, a switch from this unbounded enthusiasm to profound skepticism occurred recently after a report of the tragic death of a young man caused by injection of large amounts of an adenoviral vector into the hepatic artery (unrelated to angiogenesis therapy).2 For the scientific community, however, there has been a general lack of in-depth discussion of the potential dangers inherent in angiogenesis interventions. Such a discussion is appropriate not only because of the event cited above but also because considerable mechanistic data are available that actually permit us to identify specific side effects that we might anticipate as potential complications of angiogenesis therapy. The following therefore is a discussion of potential complications based predominantly on our knowledge of the underlying biological activities of 2 of the most potent angiogenic cytokines, vascular endothelial growth factor (VEGF) and fibroblast growth factor (FGF). Angiogenic agents are thought to have the potential to induce neovascularization in many different tissues. This becomes important in that under clinical circumstances it …

Multicenter phase II study of lapatinib in patients with brain metastases from HER2-positive breast cancer.

PURPOSE Brain metastases develop in one third of patients with advanced HER2+ breast cancer. Effective therapy for patients with central nervous system (CNS) progression after cranial radiation is extremely limited and represents a major clinical challenge. Lapatinib, an epidermal growth factor receptor/HER2 inhibitor, was associated with regressions of CNS lesions in a small phase 2 trial. The current study was done to further evaluate the CNS activity of lapatinib. The study was later amended to allow patients who progressed on lapatinib the option of receiving lapatinib plus capecitabine. EXPERIMENTAL DESIGN Eligible patients had HER2+ breast cancer, progressive brain metastases, prior trastuzumab, and cranial radiotherapy. The primary end point was CNS objective response, defined as >or=50% volumetric reduction of CNS lesion(s) in the absence of increasing steroid use, progressive neurologic signs and symptoms, or progressive extra-CNS disease. RESULTS Two-hundred and forty-two patients entered the study. CNS objective responses to lapatinib were observed in 6% of patients. In an exploratory analysis, 21% of patients experienced a >or=20% volumetric reduction in their CNS lesions. An association was observed between volumetric reduction and improvement in progression-free survival and neurologic signs and symptoms. Of the 50 evaluable patients who entered the lapatinib plus capecitabine extension, 20% experienced a CNS objective response and 40% experienced a >or=20% volumetric reduction in their CNS lesions. CONCLUSIONS This study confirms the modest CNS antitumor activity of lapatinib. Additional responses were observed with the combination of lapatinib and capecitabine. Further studies of lapatinib-based regimens for CNS metastases from HER2+ breast cancer are warranted.

The sialyltransferase ST3GAL6 influences homing and survival in multiple myeloma.

Glycosylation is a stepwise procedure of covalent attachment of oligosaccharide chains to proteins or lipids, and alterations in this process, especially increased sialylation, have been associated with malignant transformation and metastasis. The role of altered sialylation in multiple myeloma (MM) cell trafficking has not been previously investigated. In the present study we identified high expression of β-galactoside α-2,3-sialyltransferase, ST3GAL6, in MM cell lines and patients. This gene plays a key role in selectin ligand synthesis in humans through the generation of functional sialyl Lewis X. In MRC IX patients, high expression of this gene is associated with inferior overall survival. In this study we demonstrate that knockdown of ST3GAL6 results in a significant reduction in levels of α-2,3-linked sialic acid on the surface of MM cells with an associated significant reduction in adhesion to MM bone marrow stromal cells and fibronectin along with reduced transendothelial migration in vitro. In support of our in vitro findings, we demonstrate significantly reduced homing and engraftment of ST3GAL6 knockdown MM cells to the bone marrow niche in vivo, along with decreased tumor burden and prolonged survival. This study points to the importance of altered glycosylation, particularly sialylation, in MM cell adhesion and migration.

Is autoimmunity the Achilles' heel of cancer immunotherapy?

The emergence of immuno-oncology as the first broadly successful strategy for metastatic cancer will require clinicians to integrate this new pillar of medicine with chemotherapy, radiation, and targeted small-molecule compounds. Of equal importance is gaining an understanding of the limitations and toxicities of immunotherapy. Immunotherapy was initially perceived to be a relatively less toxic approach to cancer treatment than other available therapies—and surely it is, when compared to those. However, as the use of immunotherapy becomes more common, especially as first- and second-line treatments, immunotoxicity and autoimmunity are emerging as the Achilles' heel of immunotherapy. In this Perspective, we discuss evidence that the occurrence of immunotoxicity bodes well for the patient, and describe mechanisms that might be related to the induction of autoimmunity. We then explore approaches to limit immunotoxicity, and discuss the future directions of research and reporting that are needed to diminish it.

Hematopoietic stem cells and other hematopoietic cells show broad resistance to chemotherapeutic agents in vivo when overexpressing bcl-2.

Objective. Chemotherapeutic agents function by inducing apoptosis and their effectiveness depends on the balance of pro- and anti-apoptotic proteins in cells. Due to the complicated interactions of the many proteins involved, it has been difficult to determine in tumors whether overexpression of single genes is prognostic for increased resistance. Therefore, we studied the influence of bcl-2 overexpression on resistance to chemotherapeutics in a transgenic mouse system. This allowed us to study a wide variety of cells, including important but rare populations such as hematopoietic stem cells (HSC).Methods. H2K-bcl-2 transgenic and wild-type (WT) mice were treated with several agents(5-fluoruracil, cyclophosphamide, and busulfan) to determine the contribution of increased amounts of bcl-2 to the response to these chemotherapeutics in vivo. Populations were enumerated using flow cytometry. HSC were studied by FACS purification and long-term reconstitution assays in vivo and resistance was confirmed by short-term proliferation assays with different amounts of chemotherapeutics in vitro. Results. bcl-2 overexpression alone protects many cell types, though protection levels differ between populations and agents. However, even sensitive populations return to pretreatment levels faster in transgenic mice. bcl-2 overexpression also prevents the dramatic changes in HSC following 5-FU treatment (downregulation of c-kit, upregulation of Lin, less efficient long-term reconstitution). In vitro studies directly demonstrate increased resistance of bcl-2 overexpressing HSC to chemotherapeutic agents. Conclusions. Increased expression of bcl-2 in HSC and their progeny endows these cells with broad resistance to chemotherapeutic agents. The ability to (differentially) regulate sensitivity to apoptosis of bystander and tumor cells is clinically important.

Metabolic interplay between glycolysis and mitochondrial oxidation: The reverse Warburg effect and its therapeutic implication.

Aerobic glycolysis, i.e., the Warburg effect, may contribute to the aggressive phenotype of hepatocellular carcinoma. However, increasing evidence highlights the limitations of the Warburg effect, such as high mitochondrial respiration and low glycolysis rates in cancer cells. To explain such contradictory phenomena with regard to the Warburg effect, a metabolic interplay between glycolytic and oxidative cells was proposed, i.e., the "reverse Warburg effect". Aerobic glycolysis may also occur in the stromal compartment that surrounds the tumor; thus, the stromal cells feed the cancer cells with lactate and this interaction prevents the creation of an acidic condition in the tumor microenvironment. This concept provides great heterogeneity in tumors, which makes the disease difficult to cure using a single agent. Understanding metabolic flexibility by lactate shuttles offers new perspectives to develop treatments that target the hypoxic tumor microenvironment and overcome the limitations of glycolytic inhibitors.

Epigenetic therapy activates type I interferon signaling in murine ovarian cancer to reduce immunosuppression and tumor burden.

Ovarian cancer is the most lethal of all gynecological cancers, and there is an urgent unmet need to develop new therapies. Epithelial ovarian cancer (EOC) is characterized by an immune suppressive microenvironment, and response of ovarian cancers to immune therapies has thus far been disappointing. We now find, in a mouse model of EOC, that clinically relevant doses of DNA methyltransferase and histone deacetylase inhibitors (DNMTi and HDACi, respectively) reduce the immune suppressive microenvironment through type I IFN signaling and improve response to immune checkpoint therapy. These data indicate that the type I IFN response is required for effective in vivo antitumorigenic actions of the DNMTi 5-azacytidine (AZA). Through type I IFN signaling, AZA increases the numbers of CD45+ immune cells and the percentage of active CD8+ T and natural killer (NK) cells in the tumor microenvironment, while reducing tumor burden and extending survival. AZA also increases viral defense gene expression in both tumor and immune cells, and reduces the percentage of macrophages and myeloid-derived suppressor cells in the tumor microenvironment. The addition of an HDACi to AZA enhances the modulation of the immune microenvironment, specifically increasing T and NK cell activation and reducing macrophages over AZA treatment alone, while further increasing the survival of the mice. Finally, a triple combination of DNMTi/HDACi plus the immune checkpoint inhibitor α-PD-1 provides the best antitumor effect and longest overall survival, and may be an attractive candidate for future clinical trials in ovarian cancer.

Replication Fork Stability Confers Chemoresistance in BRCA-deficient Cells

Cells deficient in the Brca1 and Brca2 genes have reduced capacity to repair DNA double-strand breaks by homologous recombination and consequently are hypersensitive to DNA-damaging agents, including cisplatin and poly(ADP-ribose) polymerase (PARP) inhibitors. Here we show that loss of the MLL3/4 complex protein, PTIP, protects Brca1/2-deficient cells from DNA damage and rescues the lethality of Brca2-deficient embryonic stem cells. However, PTIP deficiency does not restore homologous recombination activity at double-strand breaks. Instead, its absence inhibits the recruitment of the MRE11 nuclease to stalled replication forks, which in turn protects nascent DNA strands from extensive degradation. More generally, acquisition of PARP inhibitors and cisplatin resistance is associated with replication fork protection in Brca2-deficient tumour cells that do not develop Brca2 reversion mutations. Disruption of multiple proteins, including PARP1 and CHD4, leads to the same end point of replication fork protection, highlighting the complexities by which tumour cells evade chemotherapeutic interventions and acquire drug resistance.

A mechanically active heterotypic E-cadherin/N-cadherin adhesion enables fibroblasts to drive cancer cell invasion

Cancer-associated fibroblasts (CAFs) promote tumour invasion and metastasis. We show that CAFs exert a physical force on cancer cells that enables their collective invasion. Force transmission is mediated by a heterophilic adhesion involving N-cadherin at the CAF membrane and E-cadherin at the cancer cell membrane. This adhesion is mechanically active; when subjected to force it triggers β-catenin recruitment and adhesion reinforcement dependent on α-catenin/vinculin interaction. Impairment of E-cadherin/N-cadherin adhesion abrogates the ability of CAFs to guide collective cell migration and blocks cancer cell invasion. N-cadherin also mediates repolarization of the CAFs away from the cancer cells. In parallel, nectins and afadin are recruited to the cancer cell/CAF interface and CAF repolarization is afadin dependent. Heterotypic junctions between CAFs and cancer cells are observed in patient-derived material. Together, our findings show that a mechanically active heterophilic adhesion between CAFs and cancer cells enables cooperative tumour invasion.

Surgical Resection for Patients with Solid Brain Metastases: Current Status

Brain metastases occur in up to 40% of patients with cancer. Their management has been revolutionized in the last decade by three developments: improved imaging and detection of metastases, better treatment of systemic disease with the result that metastases occur more often; and improved surgical techniques including image-guided surgery to treat metastatic lesions. Class 1 data suggest that surgery is a better treatment for metastases than whole brain radiation. Other data suggest that metastases even in eloquent cortex can be removed safely. The complication rate is low and the recurrence rate is less than 10%. In general, indications for surgery include a mass with an unknown primary; a symptomatic mass including one in eloquent areas; a mass with considerable edema requiring high dose steroids; a mass greater than 3 cm; or patient preference when radiosurgery may also be an option. The question of radiosurgery or whole brain radiation as adjunct to surgical removal requires further evaluation.

Epigenetic Therapy Ties MYC Depletion to Reversing Immune Evasion and Treating Lung Cancer

Combining DNA-demethylating agents (DNA methyltransferase inhibitors [DNMTis]) with histone deacetylase inhibitors (HDACis) holds promise for enhancing cancer immune therapy. Herein, pharmacologic and isoform specificity of HDACis are investigated to guide their addition to a DNMTi, thus devising a new, low-dose, sequential regimen that imparts a robust anti-tumor effect for non-small-cell lung cancer (NSCLC). Using in-vitro-treated NSCLC cell lines, we elucidate an interferon α/β-based transcriptional program with accompanying upregulation of antigen presentation machinery, mediated in part through double-stranded RNA (dsRNA) induction. This is accompanied by suppression of MYC signaling and an increase in the T cell chemoattractant CCL5. Use of this combination treatment schema in mouse models of NSCLC reverses tumor immune evasion and modulates T cell exhaustion state towards memory and effector T cell phenotypes. Key correlative science metrics emerge for an upcoming clinical trial, testing enhancement of immune checkpoint therapy for NSCLC.

Extracellular vesicles from human cardiac progenitor cells inhibit cardiomyocyte apoptosis and improve cardiac function after myocardial infarction.

AIMS Recent evidence suggests that cardiac progenitor cells (CPCs) may improve cardiac function after injury. The underlying mechanisms are indirect, but their mediators remain unidentified. Exosomes and other secreted membrane vesicles, hereafter collectively referred to as extracellular vesicles (EVs), act as paracrine signalling mediators. Here, we report that EVs secreted by human CPCs are crucial cardioprotective agents. METHODS AND RESULTS CPCs were derived from atrial appendage explants from patients who underwent heart valve surgery. CPC-conditioned medium (CM) inhibited apoptosis in mouse HL-1 cardiomyocytic cells, while enhancing tube formation in human umbilical vein endothelial cells. These effects were abrogated by depleting CM of EVs. They were reproduced by EVs secreted by CPCs, but not by those secreted by human dermal fibroblasts. Transmission electron microscopy and nanoparticle tracking analysis showed most EVs to be 30-90 nm in diameter, the size of exosomes, although smaller and larger vesicles were also present. MicroRNAs most highly enriched in EVs secreted by CPCs compared with fibroblasts included miR-210, miR-132, and miR-146a-3p. miR-210 down-regulated its known targets, ephrin A3 and PTP1b, inhibiting apoptosis in cardiomyocytic cells. miR-132 down-regulated its target, RasGAP-p120, enhancing tube formation in endothelial cells. Infarcted hearts injected with EVs from CPCs, but not from fibroblasts, exhibited less cardiomyocyte apoptosis, enhanced angiogenesis, and improved LV ejection fraction (0.8 ± 6.8 vs. -21.3 ± 4.5%; P < 0.05) compared with those injected with control medium. CONCLUSION EVs are the active component of the paracrine secretion by human CPCs. As a cell-free approach, EVs could circumvent many of the limitations of cell transplantation.

Alteration of the Antitumor Immune Response by Cancer-Associated Fibroblasts

Among cells present in the tumor microenvironment, activated fibroblasts termed cancer-associated fibroblasts (CAFs), play a critical role in the complex process of tumor-stroma interaction. CAFs, one of the prominent stromal cell populations in most types of human carcinomas, have been involved in tumor growth, angiogenesis, cancer stemness, extracellular matrix remodeling, tissue invasion, metastasis, and even chemoresistance. During the past decade, these activated tumor-associated fibroblasts have also been involved in the modulation of the anti-tumor immune response on various levels. In this review, we describe our current understanding of how CAFs accomplish this task as well as their potential therapeutic implications.

Characteristics of a monoclonal antibody (RM124) against acute myelocytic leukemia cells.

A monoclonal antibody was raised against cells from an experimental rat myelocytic leukemia (BNML). The major characteristics of the rat leukemia model resemble those of human acute myelocytic leukemia. The monoclonal antibody (MCA) RM124 was characterized with respect to its labeling pattern of BNML leukemia cells, normal rat bone marrow cells, and the hemopoietic stem cell (HSC), by flow cytometric methods and complement-dependent cytotoxicity assays. Flow cytometry revealed a much higher labeling of the leukemic cells by the MCA-RM124 compared with normal bone marrow cells, including CFU-S and CFU-C. Only a subpopulation of the normal granulocytes showed cross reactivity, however, at a lower labeling density. On using the cytotoxicity assays, it was evident that there was a selective killing of leukemic cells as compared with the activity towards the normal hemopoietic stem cells (CFU-S).

Flow-Dependent Regulation of Kruppel-Like Factor 2 Is Mediated by MicroRNA-92a.

BACKGROUND Upregulated by atheroprotective flow, the transcription factor Krüppel-like factor 2 (KLF2) is crucial for maintaining endothelial function. MicroRNAs (miRNAs) are noncoding small RNAs that regulate gene expression at the posttranscriptional level. We examined the role of miRNAs, particularly miR-92a, in the atheroprotective flow-regulated KLF2. METHODS AND RESULTS Dicer knockdown increased the level of KLF2 mRNA in human umbilical vein endothelial cells, suggesting that KLF2 is regulated by miRNA. In silico analysis predicted that miR-92a could bind to the 3' untranslated region of KLF2 mRNA. Overexpression of miR-92a decreased the expression of KLF2 and the KLF2-regulated endothelial nitric oxide synthase and thrombomodulin at mRNA and protein levels. A complementary finding is that miR-92a inhibitor increased the mRNA and protein expression of KLF2, endothelial nitric oxide synthase, and thrombomodulin. Subsequent studies revealed that atheroprotective laminar flow downregulated the level of miR-92a precursor to induce KLF2, and the level of this flow-induced KLF2 was reduced by miR-92a precursor. Furthermore, miR-92a level was lower in human umbilical vein endothelial cells exposed to the atheroprotective pulsatile shear flow than under atheroprone oscillatory shear flow. Anti-Ago1/2 immunoprecipitation coupled with real-time polymerase chain reaction revealed that pulsatile shear flow decreased the functional targeting of miR-92a precursor/KLF2 mRNA in human umbilical vein endothelial cells. Consistent with these findings, mouse carotid arteries receiving miR-92a precursor exhibited impaired vasodilatory response to flow. CONCLUSIONS Atheroprotective flow patterns decrease the level of miR-92a, which in turn increases KLF2 expression to maintain endothelial homeostasis.

Natural history of adult T-cell leukemia/lymphoma and approaches to therapy

After cell-to-cell transmission, HTLV-I increases its viral genome by de novo infection and proliferation of infected cells. Proliferation of infected cells is clonal and persistent in vivo. During the carrier state, infected cells are selected in vivo by the host's immune system, the genetic and epigenetic environment of proviral integration sites, and other factors. In leukemic cells, tax gene expression is frequently impaired by genetic and epigenetic mechanisms. Such loss of Tax expression enables ATL cells to escape the host immune system. On the other hand, ATL cells acquire the ability to proliferate without Tax by intracellular genetic and epigenetic changes. Despite advances in support and the development of novel treatment agents, the prognosis for ATLL remains poor. A number of therapies, however, do appear to improve prognosis compared to CHOP (VEPA). These include interferon-α plus zidovudine (probably after 1–2 cycles of CHOP), intensive chemotherapy as in LSG-15 with G-CSF support and Allo-SCT (which includes the potential for cure). Emerging novel approaches include HDAC inhibitors, monoclonal antibodies, and proteasome inhibitors. Comparison between different therapeutic approaches is complicated by the range of natural history of ATLL, different recruitments of naïve-to-therapy, refractory or relapsed patients, and variations in the reporting of outcome that frequently excludes difficult-to-evaluate patients. Moreover, results from relatively small proof-of-principle studies have not been extended with randomized, controlled trials. As a result, currently, there is no clear evidence to support the value of any particular treatment approach over others. To avoid further unnecessary patient suffering and to identify optimal therapy as rapidly as possible, large randomized, controlled trials encompassing multicenter, international collaborations will be necessary.

Tumor-associated macrophages correlate with the clinicopathological features and poor outcomes via inducing epithelial to mesenchymal transition in oral squamous cell carcinoma

BACKGROUND Both tumor-associated macrophages (TAMs) and the epithelial to mesenchymal transition (EMT) of cancer cells play key roles in promoting tumor progression. However, whether TAMs could induce EMT in the progression of oral squamous cell carcinoma (OSCC) remains undefined. RESULTS Here we detected the expression of macrophages markers CD68 and CD163, epithelial marker E-cadherin and mesenchymal marker vimentin in 127 OSCC patients by using semi-quantitative immunohistochemistry. CD68 and CD163 expression was not confined to the infiltrating TAMs, but also detected in cancer cells. The high number of CD68-positive macrophages was correlated with poor overall survival. Meanwhile, the expression of CD163 both in macrophages and in cancer cells was associated with poor overall survival and had a significant prognostic impact in OSCC. Importantly, the expression of CD163 in cancer cells had a significant relationship with E-cadherin and vimentin. Furthermore, the incubation of TAMs conditioned medium resulted in a fibroblast-like appearance of cancer cells (HN4, HN6 and SCC9) together with the decreased/increased expression of E-cadherin/ vimentin, which were correlated with the enhanced ability of migration and invasion. CONCLUSIONS Our results indicate that TAMs could promote the EMT of cancer cells, thereby leading to the progression of oral cancer.

Stromal-epithelial metabolic coupling in cancer: integrating autophagy and metabolism in the tumor microenvironment.

Cancer cells do not exist as pure homogeneous populations in vivo. Instead they are embedded in "cancer cell nests" that are surrounded by stromal cells, especially cancer associated fibroblasts. Thus, it is not unreasonable to suspect that stromal fibroblasts could influence the metabolism of adjacent cancer cells, and visa versa. In accordance with this idea, we have recently proposed that the Warburg effect in cancer cells may be due to culturing cancer cells by themselves, out of their normal stromal context or tumor microenvironment. In fact, when cancer cells are co-cultured with fibroblasts, then cancer cells increase their mitochondrial mass, while fibroblasts lose their mitochondria. An in depth analysis of this phenomenon reveals that aggressive cancer cells are "parasites" that use oxidative stress as a "weapon" to extract nutrients from surrounding stromal cells. Oxidative stress in fibroblasts induces the autophagic destruction of mitochondria, by mitophagy. Then, stromal cells are forced to undergo aerobic glycolysis, and produce energy-rich nutrients (such as lactate and ketones) to "feed" cancer cells. This mechanism would allow cancer cells to seed anywhere, without blood vessels as a food source, as they could simply induce oxidative stress wherever they go, explaining how cancer cells survive during metastasis. We suggest that stromal catabolism, via autophagy and mitophagy, fuels the anabolic growth of tumor cells, promoting tumor progression and metastasis. We have previously termed this new paradigm "The Autophagic Tumor Stroma Model of Cancer Metabolism", or the "Reverse Warburg Effect". We also discuss how glutamine addiction (glutaminolysis) in cancer cells fits well with this new model, by promoting oxidative mitochondrial metabolism in aggressive cancer cells.

Immune cell promotion of metastasis

Metastatic disease is the major cause of death from cancer, and immunotherapy and chemotherapy have had limited success in reversing its progression. Data from mouse models suggest that the recruitment of immunosuppressive cells to tumours protects metastatic cancer cells from surveillance by killer cells, which nullifies the effects of immunotherapy and thus establishes metastasis. Furthermore, in most cases, tumour-infiltrating immune cells differentiate into cells that promote each step of the metastatic cascade and thus are novel targets for therapy. In this Review, we describe how tumour-infiltrating immune cells contribute to the metastatic cascade and we discuss potential therapeutic strategies to target these cells.

Treatment with cyclooxygenase-2 inhibitors enables repeated administration of vaccinia virus for control of ovarian cancer.

Metastatic ovarian cancer is the leading cause of death among women with gynecologic malignancies in the United States. The lack of effective treatment for patients with advanced ovarian cancer warrants development of innovative therapies. Cancer therapy using oncolytic viruses represents a promising new approach for controlling tumors. Vaccinia virus has been shown to preferentially infect tumor cells but not normal tissue. However, oncolytic therapy using recombinant viruses faces the limitation of viral clearance due to generation of neutralizing antibodies. In the current study, we found that cyclooxygenase-2 (Cox-2) inhibitors circumvented this limitation, enabling repeated administration of vaccinia virus without losing infectivity. We quantified the antivaccinia antibody response using enzyme-linked immunosorbent assay (ELISA) and neutralization assays to show that treatment of Cox-2 inhibitors inhibited the generation of neutralizing antibodies. Furthermore, we showed that combination treatment of Cox-2 inhibitors with vaccinia virus was more effective that either treatment alone in treating MOSEC/luc tumor-bearing mice. Thus, the combination of Cox-2 inhibitors and vaccinia virus represents a potential innovative approach to controlling ovarian tumors.

TGF-beta inhibition of endothelial cell proliferation: alteration of EGF binding and EGF-induced growth-regulatory (competence) gene expression.

Transforming growth factor-beta (TGF-beta) inhibits the growth of endothelial cells derived from various sources, including human umbilical vein, bovine aorta, and rat heart. Long-term exposure of rat heart endothelial cells to TGF-beta also induces dramatic changes in morphology that are characteristic of senescent cells. These changes are accompanied by a decrease in the number of high-affinity receptors for epidermal growth factor (EGF), with almost no change in total receptor number. Additionally, the EGF-induced expression of specific competence genes (c-myc, JE, KC) is decreased, whereas the induction of c-fos gene expression by EGF is unaltered by TGF-beta treatment. These data suggest that growth inhibitors such as TGF-beta may act by altering the cell's response to growth-stimulatory factors.

Therapeutic Clearance of Amyloid by Antibodies to Serum Amyloid P Component.

BACKGROUND The amyloid fibril deposits that cause systemic amyloidosis always contain the nonfibrillar normal plasma protein, serum amyloid P component (SAP). The drug (R)-1-[6-[(R)-2-carboxy-pyrrolidin-1-yl]-6-oxo-hexanoyl]pyrrolidine-2-carboxylic acid (CPHPC) efficiently depletes SAP from the plasma but leaves some SAP in amyloid deposits that can be specifically targeted by therapeutic IgG anti-SAP antibodies. In murine amyloid A type amyloidosis, the binding of these antibodies to the residual SAP in amyloid deposits activates complement and triggers the rapid clearance of amyloid by macrophage-derived multinucleated giant cells. METHODS We conducted an open-label, single-dose-escalation, phase 1 trial involving 15 patients with systemic amyloidosis. After first using CPHPC to deplete circulating SAP, we infused a fully humanized monoclonal IgG1 anti-SAP antibody. Patients with clinical evidence of cardiac involvement were not included for safety reasons. Organ function, inflammatory markers, and amyloid load were monitored. RESULTS There were no serious adverse events. Infusion reactions occurred in some of the initial recipients of larger doses of antibody; reactions were reduced by slowing the infusion rate for later patients. At 6 weeks, patients who had received a sufficient dose of antibody in relation to their amyloid load had decreased liver stiffness, as measured with the use of transient elastography. These patients also had improvements in liver function in association with a substantial reduction in hepatic amyloid load, as shown by means of SAP scintigraphy and measurement of extracellular volume by magnetic resonance imaging. A reduction in kidney amyloid load and shrinkage of an amyloid-laden lymph node were also observed. CONCLUSIONS Treatment with CPHPC followed by an anti-SAP antibody safely triggered clearance of amyloid deposits from the liver and some other tissues. (Funded by GlaxoSmithKline; ClinicalTrials.gov number, NCT01777243.).

Heparan sulfate proteoglycans mediate internalization and propagation of specific proteopathic seeds.

Recent experimental evidence suggests that transcellular propagation of fibrillar protein aggregates drives the progression of neurodegenerative diseases in a prion-like manner. This phenomenon is now well described in cell and animal models and involves the release of protein aggregates into the extracellular space. Free aggregates then enter neighboring cells to seed further fibrillization. The mechanism by which aggregated extracellular proteins such as tau and α-synuclein bind and enter cells to trigger intracellular fibril formation is unknown. Prior work indicates that prion protein aggregates bind heparan sulfate proteoglycans (HSPGs) on the cell surface to transmit pathologic processes. Here, we find that tau fibril uptake also occurs via HSPG binding. This is blocked in cultured cells and primary neurons by heparin, chlorate, heparinase, and genetic knockdown of a key HSPG synthetic enzyme, Ext1. Interference with tau binding to HSPGs prevents recombinant tau fibrils from inducing intracellular aggregation and blocks transcellular aggregate propagation. In vivo, a heparin mimetic, F6, blocks neuronal uptake of stereotactically injected tau fibrils. Finally, uptake and seeding by α-synuclein fibrils, but not huntingtin fibrils, occurs by the same mechanism as tau. This work suggests a unifying mechanism of cell uptake and propagation for tauopathy and synucleinopathy.

Acute administration of recombinant Angiopoietin-1 ameliorates multiple-organ dysfunction syndrome and improves survival in murine sepsis.

INTRODUCTION Endothelial activation leading to vascular barrier breakdown plays an essential role in the pathophysiology of multiple-organ dysfunction syndrome (MODS) in sepsis. Increasing evidence suggests that the function of the vessel-protective factor Angiopoietin-1 (Ang-1), a ligand of the endothelial-specific Tie2 receptor, is inhibited by its antagonist Angiopoietin-2 (Ang-2) during sepsis. In order to reverse the effects of the sepsis-induced suppression of Ang-1 and elevation of Ang-2 we aimed to investigate whether an intravenous injection of recombinant human (rh) Ang-1 protects against MODS in murine sepsis. METHODS Polymicrobiological abdominal sepsis was induced by cecal ligation and puncture (CLP). Mice were treated with either 1 μg of intravenous rhAng-1 or control buffer immediately after CLP induction and every 8h thereafter. Sham-operated animals served as time-matched controls. RESULTS Compared to buffer-treated controls, rhAng-1 treated septic mice showed significant improvements in several hematologic and biochemical indicators of MODS. Moreover, rhAng-1 stabilized endothelial barrier function, as evidenced by inhibition of protein leakage from lung capillaries into the alveolar compartment. Histological analysis revealed that rhAng-1 treatment attenuated leukocyte infiltration in lungs and kidneys of septic mice, probably due to reduced endothelial adhesion molecule expression in rhAng-1 treated mice. Finally, the protective effects of rhAng-1 treatment were reflected by an improved survival time in a lethal CLP model. CONCLUSIONS In a clinically relevant murine sepsis model, intravenous rhAng-1 treatment alone is sufficient to significantly improve a variety of sepsis-associated organ dysfunctions and survival time, most likely by preserving endothelial barrier function. Further studies are needed to pave the road for clinical application of this therapy concept.

Isolated liver perfusion for non-resectable liver tumours: a review.

Many treatments have been proposed for non-resectable primary or secondary hepatic cancer but the results have generally been disappointing. Isolated Hepatic Perfusion (IHP) was first attempted four decades ago but it gained acceptance only recently, after spectacular tumour responses were obtained by isolated limb perfusion with melphalan and tumour necrosis factor (TNF) for melanomas and sarcomas. Surgical isolation of the liver is a technically demanding operation that allows the safe administration of high doses of chemotherapeutics and TNF. Percutaneous techniques using balloon occlusion catheters are simpler but result in higher leakage rates from the perfusion circuit into the systemic circulation. Several phase I-II trials indicate that IHP can yield high tumour response rates, even when there is resistance to systemic chemotherapy. However, no significant advantage in overall survival has been demonstrated so far. IHP offers unique pharmacokinetic advantages for locoregional chemotherapy and biotherapy. It might also allow gene therapy with limited systemic exposure and toxicity. At present, IHP nevertheless remains an experimental treatment modality which should therefore be used in controlled trials only.

Thyroid hormone inhibits lung fibrosis in mice by improving epithelial mitochondrial function

Thyroid hormone (TH) is critical for the maintenance of cellular homeostasis during stress responses, but its role in lung fibrosis is unknown. Here we found that the activity and expression of iodothyronine deiodinase 2 (DIO2), an enzyme that activates TH, were higher in lungs from patients with idiopathic pulmonary fibrosis than in control individuals and were correlated with disease severity. We also found that Dio2-knockout mice exhibited enhanced bleomycin-induced lung fibrosis. Aerosolized TH delivery increased survival and resolved fibrosis in two models of pulmonary fibrosis in mice (intratracheal bleomycin and inducible TGF-β1). Sobetirome, a TH mimetic, also blunted bleomycin-induced lung fibrosis. After bleomycin-induced injury, TH promoted mitochondrial biogenesis, improved mitochondrial bioenergetics and attenuated mitochondria-regulated apoptosis in alveolar epithelial cells both in vivo and in vitro. TH did not blunt fibrosis in Ppargc1a- or Pink1-knockout mice, suggesting dependence on these pathways. We conclude that the antifibrotic properties of TH are associated with protection of alveolar epithelial cells and restoration of mitochondrial function and that TH may thus represent a potential therapy for pulmonary fibrosis.

Pathophysiology of obstructive nephropathy in the newborn.

Congenital obstructive nephropathy is a consequence abnormal urinary tract development resulting in renal growth failure and injury manifested by progressive tubular atrophy and interstitial fibrosis. We have studied the renal cellular and physiological response to unilateral ureteral obstruction (UUO) in the neonatal rodent (guinea pig, rat, and mouse). Whereas in the adult, UUO stimulates renal cellular proliferation, UUO in the neonate reduces nephrogenesis, glomerular maturation, and tubular cellular proliferation. This is accompanied by a proportionately greater compensatory growth of the intact opposite kidney in the neonate. Impaired renal growth and tubular atrophy are likely owing at least in part to stimulation of renal tubular apoptosis. This, in turn, may result from a combination of factors, including loss of epithelial cell polarity, a reduction in the oncoprotein bcl-2 and epidermal growth factor (EGF), and increased expression of the fibrogenic cytokine, transforming growth factor-beta1 (TGF-beta1). Infusion of EGF stimulates cellular proliferation, suppresses apoptosis, and reduces tubular atrophy and interstitial fibrosis. TGF-beta1 is regulated by the renin-angiotensin system, which is markedly activated by UUO in the neonate. The functional consequences of obstructive nephropathy in early development are hyperfiltration by remaining nephrons, followed by progressive decrease in glomerular filtration rate that may only develop in later life. Improved management of congenital urinary tract obstruction will depend on a better understanding of the cellular mechanisms, which may lead to specific treatment using gene therapy or modulators of renal growth and development.

Chemosensitization of acute myeloid leukemia (AML) following mobilization by the CXCR4 antagonist AMD3100.

The CXCR4-SDF-1 axis plays a central role in the trafficking and retention of normal and malignant stem cells in the bone marrow (BM) microenvironment. Here, we used a mouse model of acute promyelocytic leukemia (APL) and a small molecule competitive antagonist of CXCR4, AMD3100, to examine the interaction of mouse APL cells with the BM microenvironment. APL cells from a murine cathepsin G-PML-RARalpha knockin mouse were genetically modified with firefly luciferase (APL(luc)) to allow tracking by bioluminescence imaging. Coculture of APL(luc) cells with M2-10B4 stromal cells protected the leukemia cells from chemotherapy-induced apoptosis in vitro. Upon injection into syngeneic recipients, APL(luc) cells rapidly migrated to the BM followed by egress to the spleen then to the peripheral blood with death due to leukostasis by day 15. Administration of AMD3100 to leukemic mice induced a 1.6-fold increase in total leukocytes and a 9-fold increase of circulating APL blast counts, which peak at 3 hours and return to baseline by 12 hours. Treatment of leukemic mice with chemotherapy plus AMD3100 resulted in decreased tumor burden and improved overall survival compared with mice treated with chemotherapy alone. These studies provide a proof-of-principle for directing therapy to the critical tethers that promote AML-niche interactions.

Direct conversion of human fibroblasts to multilineage blood progenitors

As is the case for embryo-derived stem cells, application of reprogrammed human induced pluripotent stem cells is limited by our understanding of lineage specification. Here we demonstrate the ability to generate progenitors and mature cells of the haematopoietic fate directly from human dermal fibroblasts without establishing pluripotency. Ectopic expression of OCT4 (also called POU5F1)-activated haematopoietic transcription factors, together with specific cytokine treatment, allowed generation of cells expressing the pan-leukocyte marker CD45. These unique fibroblast-derived cells gave rise to granulocytic, monocytic, megakaryocytic and erythroid lineages, and demonstrated in vivo engraftment capacity. We note that adult haematopoietic programs are activated, consistent with bypassing the pluripotent state to generate blood fate: this is distinct from haematopoiesis involving pluripotent stem cells, where embryonic programs are activated. These findings demonstrate restoration of multipotency from human fibroblasts, and suggest an alternative approach to cellular reprogramming for autologous cell-replacement therapies that avoids complications associated with the use of human pluripotent stem cells.

Angiopoietin-1 requires p190 RhoGAP to protect against vascular leakage in vivo.

Angiopoietin-1 (Ang-1), a ligand of the endothelium-specific receptor Tie-2, inhibits permeability in the mature vasculature, but the mechanism remains unknown. Here we show that Ang-1 signals Rho family GTPases to organize the cytoskeleton into a junction-fortifying arrangement that enhances the permeability barrier function of the endothelium. Ang-1 phosphorylates Tie-2 and its downstream effector phosphatidylinositol 3-kinase. This induces activation of one endogenous GTPase, Rac1, and inhibition of another, RhoA. Loss of either part of this dual effect abrogates the cytoskeletal and anti-permeability actions of Ang-1, suggesting that coordinated GTPase regulation is necessary for the vessel-sealing effects of Ang-1. p190 RhoGAP, a GTPase regulatory protein, provides this coordinating function as it is phosphorylated by Ang-1 treatment, requires Rac1 activation, and is necessary for RhoA inhibition. Ang-1 prevents the cytoskeletal and pro-permeability effects of endotoxin but requires p190 RhoGAP to do so. Treatment with p190 RhoGAP small interfering RNA completely abolishes the ability of Ang-1 to rescue endotoxemia-induced pulmonary vascular leak and inflammation in mice. We conclude that Ang-1 prevents vascular permeability by regulating the endothelial cytoskeleton through coordinated and opposite effects on the Rho GTPases Rac1 and RhoA. By linking Rac1 activation and RhoA inhibition, p190 RhoGAP is critical to the protective effects of Ang-1 against endotoxin. These results provide mechanistic evidence that targeting the endothelium through Tie-2 may offer specific therapeutic strategies in life-threatening endotoxemic conditions such as sepsis and acute respiratory distress syndrome.

Transient delivery of modified mRNA encoding TERT rapidly extends telomeres in human cells.

Telomere extension has been proposed as a means to improve cell culture and tissue engineering and to treat disease. However, telomere extension by nonviral, nonintegrating methods remains inefficient. Here we report that delivery of modified mRNA encoding TERT to human fibroblasts and myoblasts increases telomerase activity transiently (24-48 h) and rapidly extends telomeres, after which telomeres resume shortening. Three successive transfections over a 4 d period extended telomeres up to 0.9 kb in a cell type-specific manner in fibroblasts and myoblasts and conferred an additional 28 ± 1.5 and 3.4 ± 0.4 population doublings (PDs), respectively. Proliferative capacity increased in a dose-dependent manner. The second and third transfections had less effect on proliferative capacity than the first, revealing a refractory period. However, the refractory period was transient as a later fourth transfection increased fibroblast proliferative capacity by an additional 15.2 ± 1.1 PDs, similar to the first transfection. Overall, these treatments led to an increase in absolute cell number of more than 10(12)-fold. Notably, unlike immortalized cells, all treated cell populations eventually stopped increasing in number and expressed senescence markers to the same extent as untreated cells. This rapid method of extending telomeres and increasing cell proliferative capacity without risk of insertional mutagenesis should have broad utility in disease modeling, drug screening, and regenerative medicine.

Clonal hematopoiesis of indeterminate potential and its distinction from myelodysplastic syndromes.

Recent genetic analyses of large populations have revealed that somatic mutations in hematopoietic cells leading to clonal expansion are commonly acquired during human aging. Clonally restricted hematopoiesis is associated with an increased risk of subsequent diagnosis of myeloid or lymphoid neoplasia and increased all-cause mortality. Although myelodysplastic syndromes (MDS) are defined by cytopenias, dysplastic morphology of blood and marrow cells, and clonal hematopoiesis, most individuals who acquire clonal hematopoiesis during aging will never develop MDS. Therefore, acquisition of somatic mutations that drive clonal expansion in the absence of cytopenias and dysplastic hematopoiesis can be considered clonal hematopoiesis of indeterminate potential (CHIP), analogous to monoclonal gammopathy of undetermined significance and monoclonal B-cell lymphocytosis, which are precursor states for hematologic neoplasms but are usually benign and do not progress. Because mutations are frequently observed in healthy older persons, detection of an MDS-associated somatic mutation in a cytopenic patient without other evidence of MDS may cause diagnostic uncertainty. Here we discuss the nature and prevalence of CHIP, distinction of this state from MDS, and current areas of uncertainty regarding diagnostic criteria for myeloid malignancies.

Tissue-specific alterations in the glucocorticoid sensitivity of immune cells following repeated social defeat in mice

Endogenous glucocorticoids (GC) play an important role in the termination of the inflammatory response following infection and tissue injury. However, recent findings indicate that stress can impair the anti-inflammatory capacities of these hormones. Lipopolysaccharide (LPS)-stimulated splenocytes of mice that were repeatedly subjected to social disruption (SDR) stress were less sensitive to the immunosuppressive effects of corticosterone (CORT) as demonstrated by an increased production of pro-inflammatory cytokines and enhanced cell survival. Myeloid cells expressing the marker CD11b were shown to play a key role in this process. Here we investigated the role of the bone marrow as a potential source of the GC-insensitive cells. The study revealed that LPS-stimulated bone marrow cells, in the absence of experimental stress, were virtually GC-resistant and retained high levels of cell viability after treatment with CORT. Recurrent exposure to the acute stressor over a period of 2, 4 or 6 days led to an increase in the GC sensitivity of the bone marrow cells. This increase in GC sensitivity was associated with enhanced mRNA expression of granulocyte-macrophage colony-stimulating factor (GM-CSF), an increase in the number of myeloid progenitors, and a decrease in the proportion of mature CD11b+ cells. The changes in the cellular composition of the bone marrow were accompanied by an increase in splenic CD11b+ cell numbers. Simultaneous assessment of the GC sensitivity in bone marrow and spleen revealed a significant negative correlation between both tissues suggesting that social stress causes the redistribution of GC-insensitive myeloid cells from the bone marrow to the spleen.

Targeting BRCA1 and BRCA2 Deficiencies with G-Quadruplex-Interacting Compounds

G-quadruplex (G4)-forming genomic sequences, including telomeres, represent natural replication fork barriers. Stalled replication forks can be stabilized and restarted by homologous recombination (HR), which also repairs DNA double-strand breaks (DSBs) arising at collapsed forks. We have previously shown that HR facilitates telomere replication. Here, we demonstrate that the replication efficiency of guanine-rich (G-rich) telomeric repeats is decreased significantly in cells lacking HR. Treatment with the G4-stabilizing compound pyridostatin (PDS) increases telomere fragility in BRCA2-deficient cells, suggesting that G4 formation drives telomere instability. Remarkably, PDS reduces proliferation of HR-defective cells by inducing DSB accumulation, checkpoint activation, and deregulated G2/M progression and by enhancing the replication defect intrinsic to HR deficiency. PDS toxicity extends to HR-defective cells that have acquired olaparib resistance through loss of 53BP1 or REV7. Altogether, these results highlight the therapeutic potential of G4-stabilizing drugs to selectively eliminate HR-compromised cells and tumors, including those resistant to PARP inhibition.

The sphingosine-1-phosphate receptor agonist FTY720 modulates dendritic cell trafficking in vivo.

The pro-drug FTY720 is undergoing phase III clinical trials for prevention of allograft rejection. After phosphorylation, FTY720 targets the G protein-coupled-sphingosine-1-phosphate receptor 1 (S1PR1) on lymphocytes, thereby inhibiting their egress from lymphoid organs and their recirculation to inflammatory sites. Potential effects on dendritic cell (DC) trafficking have not been evaluated. Here, we demonstrate the expression of all five S1PR subtypes (S1PR1-5) by murine DCs. Administration of FTY720 to C57BL/10 mice markedly reduced circulating T and B lymphocytes within 24 h, but not blood-borne DCs, which were enhanced significantly for up to 96 h, while DCs in lymph nodes and spleen were reduced. Numbers of adoptively transferred, fluorochrome-labeled syngeneic or allogeneic DCs in blood were increased significantly in FTY720-treated animals, while donor-derived DCs and allostimulatory activity for host naïve T cells within the spleen were reduced. Administration of the selective S1PR1 agonist SEW2871 significantly enhanced circulating DC numbers. Flow analysis revealed that CD11b, CD31/PECAM-1, CD54/ICAM-1 and CCR7 expression on blood-borne DCs was downregulated following FTY720 administration. Transendothelial migration of FTY720-P-treated immature DCs to the CCR7 ligand CCL19 was reduced. These novel data suggest that modulation of DC trafficking by FTY720 may contribute to its immunosuppressive effects.

Increased Cell Bond Tension Governs Cell Sorting at the Drosophila Anteroposterior Compartment Boundary

Subdividing proliferating tissues into compartments is an evolutionarily conserved strategy of animal development [1-6]. Signals across boundaries between compartments can result in local expression of secreted proteins organizing growth and patterning of tissues [1-6]. Sharp and straight interfaces between compartments are crucial for stabilizing the position of such organizers and therefore for precise implementation of body plans. Maintaining boundaries in proliferating tissues requires mechanisms to counteract cell rearrangements caused by cell division; however, the nature of such mechanisms remains unclear. Here we quantitatively analyzed cell morphology and the response to the laser ablation of cell bonds in the vicinity of the anteroposterior compartment boundary in developing Drosophila wings. We found that mechanical tension is approximately 2.5-fold increased on cell bonds along this compartment boundary as compared to the remaining tissue. Cell bond tension is decreased in the presence of Y-27632 [7], an inhibitor of Rho-kinase whose main effector is Myosin II [8]. Simulations using a vertex model [9] demonstrate that a 2.5-fold increase in local cell bond tension suffices to guide the rearrangement of cells after cell division to maintain compartment boundaries. Our results provide a physical mechanism in which the local increase in Myosin II-dependent cell bond tension directs cell sorting at compartment boundaries.

A switch from white to brown fat increases energy expenditure in cancer-associated cachexia.

Cancer-associated cachexia (CAC) is a wasting syndrome characterized by systemic inflammation, body weight loss, atrophy of white adipose tissue (WAT) and skeletal muscle. Limited therapeutic options are available and the underlying mechanisms are poorly defined. Here we show that a phenotypic switch from WAT to brown fat, a phenomenon termed WAT browning, takes place in the initial stages of CAC, before skeletal muscle atrophy. WAT browning is associated with increased expression of uncoupling protein 1 (UCP1), which uncouples mitochondrial respiration toward thermogenesis instead of ATP synthesis, leading to increased lipid mobilization and energy expenditure in cachectic mice. Chronic inflammation and the cytokine interleukin-6 increase UCP1 expression in WAT, and treatments that reduce inflammation or β-adrenergic blockade reduce WAT browning and ameliorate the severity of cachexia. Importantly, UCP1 staining is observed in WAT from CAC patients. Thus, inhibition of WAT browning represents a promising approach to ameliorate cachexia in cancer patients.

Prevention of radiographic-contrast-agent-induced reductions in renal function by acetylcysteine.

BACKGROUND Radiographic contrast agents can cause a reduction in renal function that may be due to reactive oxygen species. Whether the reduction can be prevented by the administration of antioxidants is unknown. METHODS We prospectively studied 83 patients with chronic renal insufficiency (mean [+/-SD] serum creatinine concentration, 2.4+/-1.3 mg per deciliter [216+/-116 micromol per liter]) who were undergoing computed tomography with a nonionic, low-osmolality contrast agent. Patients were randomly assigned either to receive the antioxidant acetylcysteine (600 mg orally twice daily) and 0.45 percent saline intravenously, before and after administration of the contrast agent, or to receive placebo and saline. RESULTS Ten of the 83 patients (12 percent) had an increase of at least 0.5 mg per deciliter (44 micromol per liter) in the serum creatinine concentration 48 hours after administration of the contrast agent: 1 of the 41 patients in the acetylcysteine group (2 percent) and 9 of the 42 patients in the control group (21 percent; P=0.01; relative risk, 0.1; 95 percent confidence interval, 0.02 to 0.9). In the acetylcysteine group, the mean serum creatinine concentration decreased significantly (P<0.001), from 2.5+/-1.3 to 2.1+/-1.3 mg per deciliter (220+/-118 to 186+/-112 micromol per liter) 48 hours after the administration of the contrast medium, whereas in the control group, the mean serum creatinine concentration increased nonsignificantly (P=0.18), from 2.4+/-1.3 to 2.6+/-1.5 mg per deciliter (212+/-114 to 226+/-133 micromol per liter) (P<0.001 for the comparison between groups). CONCLUSIONS Prophylactic oral administration of the antioxidant acetylcysteine, along with hydration, prevents the reduction in renal function induced by contrast agents in patients with chronic renal insufficiency.

Stereotactic radiosurgery plus whole-brain radiation therapy vs stereotactic radiosurgery alone for treatment of brain metastases: a randomized controlled trial.

CONTEXT In patients with brain metastases, it is unclear whether adding up-front whole-brain radiation therapy (WBRT) to stereotactic radiosurgery (SRS) has beneficial effects on mortality or neurologic function compared with SRS alone. OBJECTIVE To determine if WBRT combined with SRS results in improvements in survival, brain tumor control, functional preservation rate, and frequency of neurologic death. DESIGN, SETTING, AND PATIENTS Randomized controlled trial of 132 patients with 1 to 4 brain metastases, each less than 3 cm in diameter, enrolled at 11 hospitals in Japan between October 1999 and December 2003. INTERVENTIONS Patients were randomly assigned to receive WBRT plus SRS (65 patients) or SRS alone (67 patients). MAIN OUTCOME MEASURES The primary end point was overall survival; secondary end points were brain tumor recurrence, salvage brain treatment, functional preservation, toxic effects of radiation, and cause of death. RESULTS The median survival time and the 1-year actuarial survival rate were 7.5 months and 38.5% (95% confidence interval, 26.7%-50.3%) in the WBRT + SRS group and 8.0 months and 28.4% (95% confidence interval, 17.6%-39.2%) for SRS alone (P = .42). The 12-month brain tumor recurrence rate was 46.8% in the WBRT + SRS group and 76.4% for SRS alone group (P<.001). Salvage brain treatment was less frequently required in the WBRT + SRS group (n = 10) than with SRS alone (n = 29) (P<.001). Death was attributed to neurologic causes in 22.8% of patients in the WBRT + SRS group and in 19.3% of those treated with SRS alone (P = .64). There were no significant differences in systemic and neurologic functional preservation and toxic effects of radiation. CONCLUSIONS Compared with SRS alone, the use of WBRT plus SRS did not improve survival for patients with 1 to 4 brain metastases, but intracranial relapse occurred considerably more frequently in those who did not receive WBRT. Consequently, salvage treatment is frequently required when up-front WBRT is not used. TRIAL REGISTRATION umin.ac.jp/ctr Identifier: C000000412.

Oxymetholone Therapy of Fanconi Anemia Suppresses Osteopontin Transcription and Induces Hematopoietic Stem Cell Cycling

Androgens are widely used for treating Fanconi anemia (FA) and other human bone marrow failure syndromes, but their mode of action remains incompletely understood. Aged Fancd2(-/-) mice were used to assess the therapeutic efficacy of oxymetholone (OXM) and its mechanism of action. Eighteen-month-old Fancd2(-/-) mice recapitulated key human FA phenotypes, including reduced bone marrow cellularity, red cell macrocytosis, and peripheral pancytopenia. As in humans, chronic OXM treatment significantly improved these hematological parameters and stimulated the proliferation of hematopoietic stem and progenitor cells. RNA-Seq analysis implicated downregulation of osteopontin as an important potential mechanism for the drug's action. Consistent with the increased stem cell proliferation, competitive repopulation assays demonstrated that chronic OXM therapy eventually resulted in stem cell exhaustion. These results expand our knowledge of the regulation of hematopoietic stem cell proliferation and have direct clinical implications for the treatment of bone marrow failure.

Emerging role of bisphosphonates in the clinic--antitumor activity and prevention of metastasis to bone.

Bisphosphonates are currently used for the treatment of bone metastases, and emerging data suggest that they may also have antitumor properties. Preclinical studies have demonstrated that zoledronic acid can inhibit angiogenesis, invasion and adhesion of tumor cells, and overall tumor progression, and emerging evidence suggests that the use of these agents may impede the development of skeletal metastases. In a recent clinical study in patients with metastatic bone disease, basal levels of vascular endothelial growth factor, a factor essential for angiogenesis, were significantly reduced in patients receiving zoledronic acid, suggesting that zoledronic acid may have clinically relevant antiangiogenic properties. Early clinical data on prevention of bone metastases by the early-generation bisphosphonate clodronate have yielded promising results in patients with breast cancer, and trials are currently ongoing to assess the efficacy of clodronate in this setting. Similarly, the new-generation bisphosphonate zoledronic acid has demonstrated activity in the prevention of bone metastases in small, 18-month pilot studies in patients with high-risk solid tumors (N=40; P=0.0002). Similarly, in a separate 5-year trial, the overall survival of patients with multiple myeloma was greater in patients whose standard treatment regimens included zoledronic acid compared with standard treatment alone (P<0.01). These encouraging early clinical results supported the initiation of larger randomized trials that are currently ongoing.

Metformin reverses established lung fibrosis in a bleomycin model

Fibrosis is a pathological result of a dysfunctional repair response to tissue injury and occurs in a number of organs, including the lungs1. Cellular metabolism regulates tissue repair and remodelling responses to injury2-4. AMPK is a critical sensor of cellular bioenergetics and controls the switch from anabolic to catabolic metabolism5. However, the role of AMPK in fibrosis is not well understood. Here, we demonstrate that in humans with idiopathic pulmonary fibrosis (IPF) and in an experimental mouse model of lung fibrosis, AMPK activity is lower in fibrotic regions associated with metabolically active and apoptosis-resistant myofibroblasts. Pharmacological activation of AMPK in myofibroblasts from lungs of humans with IPF display lower fibrotic activity, along with enhanced mitochondrial biogenesis and normalization of sensitivity to apoptosis. In a bleomycin model of lung fibrosis in mice, metformin therapeutically accelerates the resolution of well-established fibrosis in an AMPK-dependent manner. These studies implicate deficient AMPK activation in non-resolving, pathologic fibrotic processes, and support a role for metformin (or other AMPK activators) to reverse established fibrosis by facilitating deactivation and apoptosis of myofibroblasts.

Long-Term ERK Inhibition in KRAS-Mutant Pancreatic Cancer Is Associated with MYC Degradation and Senescence-like Growth Suppression.

Induction of compensatory mechanisms and ERK reactivation has limited the effectiveness of Raf and MEK inhibitors in RAS-mutant cancers. We determined that direct pharmacologic inhibition of ERK suppressed the growth of a subset of KRAS-mutant pancreatic cancer cell lines and that concurrent phosphatidylinositol 3-kinase (PI3K) inhibition caused synergistic cell death. Additional combinations that enhanced ERK inhibitor action were also identified. Unexpectedly, long-term treatment of sensitive cell lines caused senescence, mediated in part by MYC degradation and p16 reactivation. Enhanced basal PI3K-AKT-mTOR signaling was associated with de novo resistance to ERK inhibitor, as were other protein kinases identified by kinome-wide siRNA screening and a genetic gain-of-function screen. Our findings reveal distinct consequences of inhibiting this kinase cascade at the level of ERK.

A CXCL1 Paracrine Network Links Cancer Chemoresistance and Metastasis

Metastasis and chemoresistance in cancer are linked phenomena, but the molecular basis for this link is unknown. We uncovered a network of paracrine signals between carcinoma, myeloid, and endothelial cells that drives both processes in breast cancer. Cancer cells that overexpress CXCL1 and 2 by transcriptional hyperactivation or 4q21 amplification are primed for survival in metastatic sites. CXCL1/2 attract CD11b(+)Gr1(+) myeloid cells into the tumor, which produce chemokines including S100A8/9 that enhance cancer cell survival. Although chemotherapeutic agents kill cancer cells, these treatments trigger a parallel stromal reaction leading to TNF-α production by endothelial and other stromal cells. TNF-α via NF-kB heightens the CXCL1/2 expression in cancer cells, thus amplifying the CXCL1/2-S100A8/9 loop and causing chemoresistance. CXCR2 blockers break this cycle, augmenting the efficacy of chemotherapy against breast tumors and particularly against metastasis. This network of endothelial-carcinoma-myeloid signaling interactions provides a mechanism linking chemoresistance and metastasis, with opportunities for intervention.

Microfluidic platform to evaluate migration of cells from patients with DYT1 dystonia.

BACKGROUND Microfluidic platforms for quantitative evaluation of cell biologic processes allow low cost and time efficient research studies of biological and pathological events, such as monitoring cell migration by real-time imaging. In healthy and disease states, cell migration is crucial in development and wound healing, as well as to maintain the body's homeostasis. NEW METHOD The microfluidic chambers allow precise measurements to investigate whether fibroblasts carrying a mutation in the TOR1A gene, underlying the hereditary neurologic disease--DYT1 dystonia, have decreased migration properties when compared to control cells. RESULTS We observed that fibroblasts from DYT1 patients showed abnormalities in basic features of cell migration, such as reduced velocity and persistence of movement. COMPARISON WITH EXISTING METHOD The microfluidic method enabled us to demonstrate reduced polarization of the nucleus and abnormal orientation of nuclei and Golgi inside the moving DYT1 patient cells compared to control cells, as well as vectorial movement of single cells. CONCLUSION We report here different assays useful in determining various parameters of cell migration in DYT1 patient cells as a consequence of the TOR1A gene mutation, including a microfluidic platform, which provides a means to evaluate real-time vectorial movement with single cell resolution in a three-dimensional environment.

Reprogramming of human fibroblasts to pluripotency with lineage specifiers.

Since the initial discovery that OCT4, SOX2, KLF4, and c-MYC overexpression sufficed for the induction of pluripotency in somatic cells, methodologies replacing the original factors have enhanced our understanding of the reprogramming process. However, unlike in mouse, OCT4 has not been replaced successfully during reprogramming of human cells. Here we report on a strategy to accomplish this replacement. Through a combination of transcriptome and bioinformatic analysis we have identified factors previously characterized as being lineage specifiers that are able to replace OCT4 and SOX2 in the reprogramming of human fibroblasts. Our results show that it is possible to replace OCT4 and SOX2 simultaneously with alternative lineage specifiers in the reprogramming of human cells. At a broader level, they also support a model in which counteracting lineage specification networks underlies the induction of pluripotency.

Hepatitis C virus and blood transfusion: past and present risks.

The risk of HCV transmission by blood and blood products has been greatly reduced since the early 1980's. Selection of non-remunerated donors, donor selection to prevent HIV transmission, initial surrogate testing in some regions, and introduction of anti-HCV testing have all contributed to this. ALT surrogate testing has become obsolete since the introduction of anti-HCV testing. The residual risk of HCV transmission due to donations in the anti-HCV window period at present is about 1 in 100 000 transfusions of cellular products, and transmission of HCV by plasma products treated with modern inactivation methods such as solvent-detergent treatment, has not been reported. Hemovigilance programmes, which are presently being installed, will provide more data on the safety of blood transfusion. Introduction of HCV nucleic amplification technology (NAT) as a quality control of manufacturing pools for plasma products or as a form of blood donor screening by minipools is anticipated in many European countries for the coming year. Given industrial developments, NAT testing of individual blood donations may become available within the next 2 years. HCV NAT testing will further annihilate the residual risk, and the cost-effectiveness will become relatively low in comparison with other public health measures.

E-cadherin engagement stimulates proliferation via Rac1

E-cadherin has been linked to the suppression of tumor growth and the inhibition of cell proliferation in culture. We observed that progressively decreasing the seeding density of normal rat kidney-52E (NRK-52E) or MCF-10A epithelial cells from confluence, indeed, released cells from growth arrest. Unexpectedly, a further decrease in seeding density so that cells were isolated from neighboring cells decreased proliferation. Experiments using microengineered substrates showed that E-cadherin engagement stimulated the peak in proliferation at intermediate seeding densities, and that the proliferation arrest at high densities did not involve E-cadherin, but rather resulted from a crowding-dependent decrease in cell spreading against the underlying substrate. Rac1 activity, which was induced by E-cadherin engagement specifically at intermediate seeding densities, was required for the cadherin-stimulated proliferation, and the control of Rac1 activation by E-cadherin was mediated by p120-catenin. Together, these findings demonstrate a stimulatory role for E-cadherin in proliferative regulation, and identify a simple mechanism by which cell–cell contact may trigger or inhibit epithelial cell proliferation in different settings.

Stromal Fibroblasts Present in Invasive Human Breast Carcinomas Promote Tumor Growth and Angiogenesis through Elevated SDF-1/CXCL12 Secretion

Fibroblasts often constitute the majority of the stromal cells within a breast carcinoma, yet the functional contributions of these cells to tumorigenesis are poorly understood. Using a coimplantation tumor xenograft model, we demonstrate that carcinoma-associated fibroblasts (CAFs) extracted from human breast carcinomas promote the growth of admixed breast carcinoma cells significantly more than do normal mammary fibroblasts derived from the same patients. The CAFs, which exhibit the traits of myofibroblasts, play a central role in promoting the growth of tumor cells through their ability to secrete stromal cell-derived factor 1 (SDF-1); CAFs promote angiogenesis by recruiting endothelial progenitor cells (EPCs) into carcinomas, an effect mediated in part by SDF-1. CAF-secreted SDF-1 also stimulates tumor growth directly, acting through the cognate receptor, CXCR4, which is expressed by carcinoma cells. Our findings indicate that fibroblasts within invasive breast carcinomas contribute to tumor promotion in large part through the secretion of SDF-1.

The shunt problem: control of functional shunting in normal and tumour vasculature

Networks of blood vessels in normal and tumour tissues have heterogeneous structures, with widely varying blood flow pathway lengths. To achieve efficient blood flow distribution, mechanisms for the structural adaptation of vessel diameters must be able to inhibit the formation of functional shunts (whereby short pathways become enlarged and flow bypasses long pathways). Such adaptation requires information about tissue metabolic status to be communicated upstream to feeding vessels, through conducted responses. We propose that impaired vascular communication in tumour microvascular networks, leading to functional shunting, is a primary cause of dysfunctional microcirculation and local hypoxia in cancer. We suggest that anti-angiogenic treatment of tumours may restore vascular communication and thereby improve or normalize flow distribution in tumour vasculature.

[Neutrophils and macrophages related to the pathogenesis and disease development of chronic obstructive pulmonary disease by the inflammatory reaction].

Chronic obstructive pulmonary disease (COPD) is a chronic airway disorder characterized by obstructive airflow limitation which is not completely reversible with treatment. Inflammatory changes in the peripheral airways, especially those with the diameter less than 2mm (so-called small airway disease) have been speculated to be initial steps of COPD. And so it must be quite clear that neutrophils and macrophages play an essential role in the pathogenesis of these lesions. Studies with bronchoalveolar lavage demonstrated an increase in neutrophil numbers and the neutrophil chemoattractant interleukin-8. Recent studies demonstrated that neutrophils and macrophages are increased and contain a variety of proteases, which are involved in cell infiltration and activation. Studies with gene-engineered animals and anti-cytokine treatment will facilitate better understanding the role of neutrophils and macrophages, and eventual novel therapy.

Oncogenic mTOR signaling recruits myeloid-derived suppressor cells to promote tumor initiation

Myeloid-derived suppressor cells (MDSCs) play critical roles in primary and metastatic cancer progression. MDSC regulation is widely variable even among patients harbouring the same type of malignancy, and the mechanisms governing such heterogeneity are largely unknown. Here, integrating human tumour genomics and syngeneic mammary tumour models, we demonstrate that mTOR signalling in cancer cells dictates a mammary tumour's ability to stimulate MDSC accumulation through regulating G-CSF. Inhibiting this pathway or its activators (for example, FGFR) impairs tumour progression, which is partially rescued by restoring MDSCs or G-CSF. Tumour-initiating cells (TICs) exhibit elevated G-CSF. MDSCs reciprocally increase TIC frequency through activating Notch in tumour cells, forming a feedforward loop. Analyses of primary breast cancers and patient-derived xenografts corroborate these mechanisms in patients. These findings establish a non-canonical oncogenic role of mTOR signalling in recruiting pro-tumorigenic MDSCs and show how defined cancer subsets may evolve to promote and depend on a distinct immune microenvironment.

Mechanosignaling through YAP and TAZ drives fibroblast activation and fibrosis.

Pathological fibrosis is driven by a feedback loop in which the fibrotic extracellular matrix is both a cause and consequence of fibroblast activation. However, the molecular mechanisms underlying this process remain poorly understood. Here we identify yes-associated protein (YAP) (homolog of drosophila Yki) and transcriptional coactivator with PDZ-binding motif (TAZ) (also known as Wwtr1), transcriptional effectors of the Hippo pathway, as key matrix stiffness-regulated coordinators of fibroblast activation and matrix synthesis. YAP and TAZ are prominently expressed in fibrotic but not healthy lung tissue, with particularly pronounced nuclear expression of TAZ in spindle-shaped fibroblastic cells. In culture, both YAP and TAZ accumulate in the nuclei of fibroblasts grown on pathologically stiff matrices but not physiologically compliant matrices. Knockdown of YAP and TAZ together in vitro attenuates key fibroblast functions, including matrix synthesis, contraction, and proliferation, and does so exclusively on pathologically stiff matrices. Profibrotic effects of YAP and TAZ operate, in part, through their transcriptional target plasminogen activator inhibitor-1, which is regulated by matrix stiffness independent of transforming growth factor-β signaling. Immortalized fibroblasts conditionally expressing active YAP or TAZ mutant proteins overcome soft matrix limitations on growth and promote fibrosis when adoptively transferred to the murine lung, demonstrating the ability of fibroblast YAP/TAZ activation to drive a profibrotic response in vivo. Together, these results identify YAP and TAZ as mechanoactivated coordinators of the matrix-driven feedback loop that amplifies and sustains fibrosis.

Neutrophils Suppress Intraluminal NK Cell-Mediated Tumor Cell Clearance and Enhance Extravasation of Disseminated Carcinoma Cells.

UNLABELLED Immune cells promote the initial metastatic dissemination of carcinoma cells from primary tumors. In contrast to their well-studied functions in the initial stages of metastasis, the specific roles of immunocytes in facilitating progression through the critical later steps of the invasion-metastasis cascade remain poorly understood. Here, we define novel functions of neutrophils in promoting intraluminal survival and extravasation at sites of metastatic dissemination. We show that CD11b(+)/Ly6G(+) neutrophils enhance metastasis formation via two distinct mechanisms. First, neutrophils inhibit natural killer cell function, which leads to a significant increase in the intraluminal survival time of tumor cells. Thereafter, neutrophils operate to facilitate extravasation of tumor cells through the secretion of IL1β and matrix metalloproteinases. These results identify neutrophils as key regulators of intraluminal survival and extravasation through their cross-talk with host cells and disseminating carcinoma cells. SIGNIFICANCE This study provides important insights into the systemic contributions of neutrophils to cancer metastasis by identifying how neutrophils facilitate intermediate steps of the invasion-metastasis cascade. We demonstrate that neutrophils suppress natural killer cell activity and increase extravasation of tumor cells. Cancer Discov; 6(6); 630-49. ©2016 AACR.This article is highlighted in the In This Issue feature, p. 561.

Glucocorticoid with cyclophosphamide for paraquat-induced lung fibrosis.

BACKGROUND Paraquat is an effective and widely used herbicide but is also a lethal poison. In many developing countries paraquat is widely available and inexpensive, making poisoning prevention difficult. However most of the people who become poisoned from paraquat have taken it as a means of suicide. Standard treatment for paraquat poisoning both prevents further absorption and reduces the load of paraquat in the blood through haemoperfusion or haemodialysis. The effectiveness of standard treatments is extremely limited. The immune system plays an important role in exacerbating paraquat-induced lung fibrosis. Immunosuppressive treatment using glucocorticoid and cyclophosphamide in combination is being developed and studied. OBJECTIVES To assess the effects of glucocorticoid with cyclophosphamide on mortality in patients with paraquat-induced lung fibrosis. SEARCH METHODS To identify randomised controlled trials (RCTs) on this topic, we searched the Cochrane Injuries Group's Specialised Register (searched 1 February 2012), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2012, Issue 1), MEDLINE (Ovid SP) (1946 January Week 3 2012), EMBASE (Ovid SP) (1947 to Week 4 2012), ISI Web of Science: Science Citation Index Expanded (SCI-EXPANDED) (1970 to January 2012), ISI Web of Science: Conference Proceedings Citation Index - Science (CPCI-S) (1990 to January 2012), Chinese Biomedical Literature and Retrieval System (CBM) (1978 to April 2012), Chinese Medical Current Contents (CMCC) (1995 to April 2012), and Chinese Medical Academic Conference (CMAC) (1994 to April 2012). Searches were completed on English language databases on 1 February 2012 and on Chinese language databases on 12 April 2012. SELECTION CRITERIA RCTs were included in this review. All patients were to receive standard care, plus the intervention or control. The intervention was glucocorticoid with cyclophosphamide in combination versus a control of a placebo, standard care alone or any other therapy in addition to standard care. DATA COLLECTION AND ANALYSIS The mortality risk ratio (RR) and 95% confidence interval (CI) was calculated for each study on an intention-to-treat basis. Data for all-cause mortality at final follow-up were summarised in a meta-analysis using a fixed-effect model. MAIN RESULTS This systematic review includes three trials with a combined total of 164 participants who had moderate to severe paraquat poisoning. Patients who received glucocorticoid with cyclophosphamide in addition to standard care had a lower risk of death at final follow-up than those receiving standard care only (RR 0.72; 95% CI 0.59 to 0.89). AUTHORS' CONCLUSIONS Based on the findings of three small RCTs of moderate to severely poisoned patients, glucocorticoid with cyclophosphamide in addition to standard care may be a beneficial treatment for patients with paraquat-induced lung fibrosis. To enable further study of the effects of glucocorticoid with cyclophosphamide for patients with moderate to severe paraquat poisoning, hospitals may provide this treatment as part of an RCT with allocation concealment.

Parasite multiplication potential and the severity of Falciparum malaria.

The multiplication rates and invasiveness of Plasmodium falciparum parasites isolated from adult Thai patients hospitalized with uncomplicated malaria (n=34) were compared with those from persons with severe malaria (n=42). To simulate severe malaria and control for host effects, the in vitro cultures were adjusted to 1% parasitemia and used the same red blood cell donor. P. falciparum isolates from persons with severe malaria had initial cycle multiplication rates in vitro that were 3-fold higher than those from uncomplicated malaria (median [95% confidence interval], 8.3 [7. 1-10.5] vs. 2.8 [1.7-3.9]; P=.001). Parasites causing severe malaria exhibited unrestricted red blood cell invasion, whereas those from uncomplicated malaria were restricted to a geometric mean of 40 (31%-53%) of red blood cells. P. falciparum parasites causing severe malaria were less selective and multiplied more at high parasitemias than those causing uncomplicated malaria.

Hallmarks of Cancer: The Next Generation

The hallmarks of cancer comprise six biological capabilities acquired during the multistep development of human tumors. The hallmarks constitute an organizing principle for rationalizing the complexities of neoplastic disease. They include sustaining proliferative signaling, evading growth suppressors, resisting cell death, enabling replicative immortality, inducing angiogenesis, and activating invasion and metastasis. Underlying these hallmarks are genome instability, which generates the genetic diversity that expedites their acquisition, and inflammation, which fosters multiple hallmark functions. Conceptual progress in the last decade has added two emerging hallmarks of potential generality to this list-reprogramming of energy metabolism and evading immune destruction. In addition to cancer cells, tumors exhibit another dimension of complexity: they contain a repertoire of recruited, ostensibly normal cells that contribute to the acquisition of hallmark traits by creating the "tumor microenvironment. " Recognition of the widespread applicability of these concepts will increasingly affect the development of new means to treat human cancer.

Modulation of Replicative Lifespan in Cryptococcus neoformans: Implications for Virulence

The fungal pathogen, Cryptococcus neoformans, has been shown to undergo replicative aging. Old cells are characterized by advanced generational age and phenotypic changes that appear to mediate enhanced resistance to host and antifungal-based killing. As a consequence of this age-associated resilience, old cells accumulate during chronic infection. Based on these findings, we hypothesized that shifting the generational age of a pathogenic yeast population would alter its vulnerability to the host and affect its virulence. SIR2 is a well-conserved histone deacetylase, and a pivotal target for the development of anti-aging drugs. We tested its effect on C. neoformans' replicative lifespan (RLS). First, a mutant C. neoformans strain (sir2Δ) was generated, and confirmed a predicted shortened RLS in sir2Δ cells consistent with its known role in aging. Next, RLS analysis showed that treatment of C. neoformans with Sir2p-agonists resulted in a significantly prolonged RLS, whereas treatment with a Sir2p-antagonist shortened RLS. RLS modulating effects were dependent on SIR2 and not observed in sir2Δ cells. Because SIR2 loss resulted in a slightly impaired fitness, effects of genetic RLS modulation on virulence could not be compared with wild type cells. Instead we chose to chemically modulate RLS, and investigated the effect of Sir2p modulating drugs on C. neoformans cells in a Galleria mellonella infection model. Consistent with our hypothesis that shifts in the generational age of the infecting yeast population alters its vulnerability to host cells, we observed decreased virulence of C. neoformans in the Galleria host when RLS was prolonged by treatment with Sir2p agonists. In contrast, treatment with a Sir2p antagonist, which shortens RLS enhanced virulence in Galleria. In addition, combination of Sir2p agonists with antifungal therapy enhanced the antifungal's effect. Importantly, no difference in virulence was observed with drug treatment when sir2Δ cells were used for infection, which confirmed target specificity and ruled out non-specific effects of the drugs on the Galleria host. Thus, this study suggests that RLS modulating drugs, such as Sir2p agonists, shift lifespan and vulnerability of the fungal population, and should be further investigated as a potential class of novel antifungal drug targets that can enhance antifungal efficacy.

Involving family members in cancer care: focus group considerations of patients and oncological providers.

Family members are an integral part of a patient's cancer care from the moment the diagnosis is delivered to the conclusion of treatment. Family members bring with them a range of emotional reactions, interpersonal dynamics and expectations for the care the patient receives. This study is part of a multi-institutional project to continue to improve the process of cancer care. In this study, 19 focus groups (11 patient and 8 provider) were conducted concerning issues related to doctor-patient communication in eight cancer centers in the United States. The content of the conversations was analyzed and thematic categories emerged that highlight the various strengths and difficulties associated with family involvement. The focus groups' comments support the need for explicit conversations between professional caregivers, patients and their loved ones, in order to negotiate the expectations and needs of each team member. Implications for clinical practice and strategies for working with family members are offered.

Phagocytosis and deposition of vascular beta-amyloid in rat brains injected with Alzheimer beta-amyloid.

The presence of extracellular deposits of beta-amyloid protein in the brain is a hallmark of Alzheimer's disease (AD). In an effort to determine the effect of amyloid in an animal model, the authors injected amyloid cores isolated from AD brains into the cortex and hippocampus of rats. Lipofuscin, a major contaminant of the plaque core preparation, was injected on the contralateral side and used as a control to induce an analogous phagocytic cell response. Rats were sacrificed 2 days, 7 days, and 1 month after injection and amyloid located by four histochemical techniques. Amyloid and lipofuscin move from the site of injection into otherwise undamaged neuropil, persist for at least 1 month and are both associated with increases in glial fibrillary acidic protein and microglia (OX-42) staining. By 1 week, many of the amyloid cores are ingested by phagocytes. Some of the beta-amyloid-containing phagocytes migrate to the vessels and to the ventricles, and by 1 month, a significant amount of the amyloid is directly associated with the vessels. This suggests that phagocytic cells can internalize exogenous amyloid and attempt to clear it from the central nervous system (CNS). Therefore, the observed distribution of amyloid is not necessarily the initial site of deposition.

Tissue exit: a novel control point in the accumulation of antigen-specific CD8 T cells in the influenza a virus-infected lung.

Memory/effector T cells efficiently migrate into extralymphoid tissues and sites of infection, providing immunosurveillance and a first line of defense against invading pathogens. Even though it is a potential means to regulate the size, quality, and duration of a tissue infiltrate, T cell egress from infected tissues is poorly understood. Using a mouse model of influenza A virus infection, we found that CD8 effector T cells egressed from the infected lung in a CCR7-dependent manner. In contrast, following antigen recognition, effector CD8 T cell egress decreased and CCR7 function was reduced in vivo and in vitro, indicating that the exit of CD8 T cells from infected tissues is tightly regulated. Our data suggest that the regulation of T cell egress is a mechanism to retain antigen-specific effectors at the site of infection to promote viral clearance, while decreasing the numbers of bystander T cells and preventing overt inflammation.

Targeted therapy for cancer stem cells: the patched pathway and ABC transporters

Data from certain leukemias as well as brain and breast cancer indicate that there is a small population of tumor cells with ‘stem cell’ characteristics and the capacity for self-renewal. The self-renewing cells have many of the properties of normal stem cells and have been termed ‘cancer stem cells’. These cancer stem cells make up as few as 1% of the cells in a tumor, making them difficult to detect and study. Like normal stem cells, cancer stem cells have a number of properties permitting them to survive traditional cancer chemotherapy and radiation therapy. These cells express high levels of ATP-binding cassette (ABC) drug transporters, providing for a level of resistance; are relatively quiescent; have higher levels of DNA repair and a lowered ability to enter apoptosis. Combined cancer therapy approaches targeting the cancer stem cells and the non-stem cells may be developed with increased efficacy. Efforts to target the Hedgehog/Patched pathway, critical to embryonic growth and differentiation, and the ABCG2 drug efflux transporter will be presented.

CD4+ T cell-mediated cytotoxicity eliminates primary tumor cells in metastatic melanoma through high MHC class II expression and can be enhanced by inhibitory receptor blockade

Metastatic melanoma is a rapidly progressing disease with high mortality rate and limited treatment options. Immunotherapy based on tumor-targeting cytotoxic T cell responses represents a promising strategy. To assist in its development, we examined the possibility and efficacy of using CD4+ cytotoxic T cells. The regulatory mechanisms controlling CD4+ T cell-mediated cytotoxicity were also investigated. We found that naturally occurring granzyme B and perforin-expressing CD4+ cytotoxic T cells can be recovered from metastatic melanoma patients at significantly elevated frequencies compared to those from healthy controls. These CD4+ cytotoxic T cells were also capable of killing autologous tumor cells harvested from metastatic melanoma, independent of CD8+ T cells or any other cell types. However, several restricting factors were observed. First, the cytolytic activity by CD4+ T cells required high MHC class II expression on melanoma cells, which was not satisfied in a subset of melanomas. Second, the granzyme B and perforin release by activated CD4+ cytotoxic T cells was reduced after coculturing with autologous melanoma cells, characterized by low LAMP-1 expression and low granzyme B and perforin secretion in the supernatant. This suggested that inhibitory mechanisms were present to suppress CD4+ cytotoxic T cells. Indeed, blockade of PD-1 and CTLA-4 had increased the cytolytic activity of CD4+ T cells but was only effective in MHC class II high but not MHC class II low melanomas. Together, our study showed that CD4+ T cell-mediated cytotoxicity could eliminate primary melanoma cells but the efficacy depended on MHC class II expression.

Modulation of cancer chemotherapy by green tea.

Biochemical modulation has played an important role in the development of cancer chemotherapy. We have directed our attention to the intake of common beverages and investigated the effects of green tea and tea components on the antitumor activity of doxorubicin. We carried out the combined treatment of toxorubicin and green tea on Ehrlich ascites carcinoma tumor-bearing mice. The oral administration of green tea enhanced 2.5-fold the inhibitory effects of doxorubicin on tumor growth. The Doxorubicin concentration in the tumor was increased by the combination of green tea with doxorubicin. In contrast, the increase in doxorubicin concentration was not observed in normal tissues after green tea combination. Furthermore, the enhancement of antitumor activity of doxorubicin induced by green tea was observed in M5076 ovarian sarcoma, which has low sensitivity to doxorubicin. These results suggest that drinking green tea can encourage cancer chemotherapy and may improve the quality of life of clinical patients.

Subversion of Systemic Glucose Metabolism as a Mechanism to Support the Growth of Leukemia Cells.

From an organismal perspective, cancer cell populations can be considered analogous to parasites that compete with the host for essential systemic resources such as glucose. Here, we employed leukemia models and human leukemia samples to document a form of adaptive homeostasis, where malignant cells alter systemic physiology through impairment of both host insulin sensitivity and insulin secretion to provide tumors with increased glucose. Mechanistically, tumor cells induce high-level production of IGFBP1 from adipose tissue to mediate insulin sensitivity. Further, leukemia-induced gut dysbiosis, serotonin loss, and incretin inactivation combine to suppress insulin secretion. Importantly, attenuated disease progression and prolonged survival are achieved through disruption of the leukemia-induced adaptive homeostasis. Our studies provide a paradigm for systemic management of leukemic disease.