human
The task is to decide the Hallmarks of Cancer (HOC) taxonomy of the article based on its abstract. The input is an abstract text. There are 10 topics you will need to decide whether the article is related to. Topics: sustaining proliferative signaling, evading growth suppressors, resisting cell death, enabling replicative immortality, inducing angiogenesis, activating invasion and metastasis, genomic instability and mutation, tumor promoting inflammation, cellular energetics, avoiding immune destruction. The output should be topics from the above 10 topics, that are related to the input article. Please note one article can be related to multiple topics. Output format: provide a semicolon-separated list of relevant topics.
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    INPUT: PURPOSE Osteosarcoma is an aggressive primary bone cancer characterized by expression of platelet-derived growth factor ( PDGF ) and its cognate receptor . Coexpression of the growth factor and receptor suggests their role in autocrine or paracrine growth mechanisms . It has been reported previously that STI571 has specific activity in inhibiting select tyrosine kinase receptors , including PDGF and c-Kit . Osteosarcomas express low levels of c-Kit but abundant levels of PDGF receptor ( PDGFR ) . EXPERIMENTAL DESIGN To investigate the potential of STI571 as therapy for osteosarcoma , we studied its effects on PDGF-mediated cell growth in vitro and in an in vivo mouse model . RESULTS PDGF acted as a potent mitogen in a dose-dependent manner in two osteosarcoma cell lines . STI571 ( 1.0 micro M ) inhibited both PDGFR-alpha and PDGFR-beta phosphorylation and the downstream phosphorylation targets extracellular signal-regulated kinase and Akt . STI571 also inhibited PDGF-mediated growth and induced apoptosis in vitro as determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and terminal deoxynucleotidyl transferase-mediated nick end labeling staining . To study the effect of STI571 alone or in combination with Taxol in an in vivo model , an osteosarcoma cell line ( KRIB ) was transplanted into the tibia of athymic nude mice . Mice were treated with STI571 ( 50 mg/kg p.o. q M-F ) , Taxol ( 8 mg/kg i.p. weekly ) , or STI571 plus Taxol for 6 weeks . There was no significant difference in tumor size between treatment and control mice . Aberrant signaling pathways downstream of the PDGFR in the v-Ki-ras oncogene-transformed KRIB cell line may in part explain this finding . CONCLUSIONS Our data demonstrate that STI571 inhibits PDGF-mediated growth and leads to apoptosis of osteosarcoma cells in vitro by selective inhibition of the PDGFR tyrosine kinase . The effectiveness of STI571 in our studies suggests targeting of PDGFRs as a novel treatment for osteosarcoma .
    OUTPUT:

agent
sustaining proliferative signaling;resisting cell death
The task is to decide the Hallmarks of Cancer (HOC) taxonomy of the article based on its abstract. The input is an abstract text. There are 10 topics you will need to decide whether the article is related to. Topics: sustaining proliferative signaling, evading growth suppressors, resisting cell death, enabling replicative immortality, inducing angiogenesis, activating invasion and metastasis, genomic instability and mutation, tumor promoting inflammation, cellular energetics, avoiding immune destruction. The output should be topics from the above 10 topics, that are related to the input article. Please note one article can be related to multiple topics. Output format: provide a semicolon-separated list of relevant topics.
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    INPUT: PURPOSE Osteosarcoma is an aggressive primary bone cancer characterized by expression of platelet-derived growth factor ( PDGF ) and its cognate receptor . Coexpression of the growth factor and receptor suggests their role in autocrine or paracrine growth mechanisms . It has been reported previously that STI571 has specific activity in inhibiting select tyrosine kinase receptors , including PDGF and c-Kit . Osteosarcomas express low levels of c-Kit but abundant levels of PDGF receptor ( PDGFR ) . EXPERIMENTAL DESIGN To investigate the potential of STI571 as therapy for osteosarcoma , we studied its effects on PDGF-mediated cell growth in vitro and in an in vivo mouse model . RESULTS PDGF acted as a potent mitogen in a dose-dependent manner in two osteosarcoma cell lines . STI571 ( 1.0 micro M ) inhibited both PDGFR-alpha and PDGFR-beta phosphorylation and the downstream phosphorylation targets extracellular signal-regulated kinase and Akt . STI571 also inhibited PDGF-mediated growth and induced apoptosis in vitro as determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and terminal deoxynucleotidyl transferase-mediated nick end labeling staining . To study the effect of STI571 alone or in combination with Taxol in an in vivo model , an osteosarcoma cell line ( KRIB ) was transplanted into the tibia of athymic nude mice . Mice were treated with STI571 ( 50 mg/kg p.o. q M-F ) , Taxol ( 8 mg/kg i.p. weekly ) , or STI571 plus Taxol for 6 weeks . There was no significant difference in tumor size between treatment and control mice . Aberrant signaling pathways downstream of the PDGFR in the v-Ki-ras oncogene-transformed KRIB cell line may in part explain this finding . CONCLUSIONS Our data demonstrate that STI571 inhibits PDGF-mediated growth and leads to apoptosis of osteosarcoma cells in vitro by selective inhibition of the PDGFR tyrosine kinase . The effectiveness of STI571 in our studies suggests targeting of PDGFRs as a novel treatment for osteosarcoma .
    OUTPUT:
