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: BACKGROUND Death receptors ( DR ) of the TNF family function as anti-tumor immune effector molecules . Tumor cells , however , often exhibit DR-signaling resistance . Previous studies indicate that radiation can modify gene expression within tumor cells and increase tumor cell sensitivity to immune attack . The aim of this study is to investigate the synergistic effect of sub-lethal doses of ionizing radiation in sensitizing colorectal carcinoma cells to death receptor-mediated apoptosis . METHODOLOGY/PRINCIPAL FINDINGS The ability of radiation to modulate the expression of multiple death receptors ( Fas/CD95 , TRAILR1/DR4 , TRAILR2/DR5 , TNF-R1 and LTÎ²R ) was examined in colorectal tumor cells . The functional significance of sub-lethal doses of radiation in enhancing tumor cell susceptibility to DR-induced apoptosis was determined by in vitro functional sensitivity assays . The longevity of these changes and the underlying molecular mechanism of irradiation in sensitizing diverse colorectal carcinoma cells to death receptor-mediated apoptosis were also examined . We found that radiation increased surface expression of Fas , DR4 and DR5 but not LTÎ²R or TNF-R1 in these cells . Increased expression of DRs was observed 2 days post-irradiation and remained elevated 7-days post irradiation . Sub-lethal tumor cell irradiation alone exhibited minimal cell death , but effectively sensitized three of three colorectal carcinoma cells to both TRAIL and Fas-induced apoptosis , but not LTÎ²R-induced death . Furthermore , radiation-enhanced Fas and TRAIL-induced cell death lasted as long as 5-days post-irradiation . Specific analysis of intracellular sensitizers to apoptosis indicated that while radiation did reduce Bcl-X(L) and c-FLIP protein expression , this reduction did not correlate with the radiation-enhanced sensitivity to Fas and/or TRAIL mediated apoptosis among the three cell types . CONCLUSIONS/SIGNIFICANCE Irradiation of tumor cells can overcome Fas and TRAIL resistance that is long lasting . Overall , results of these investigations suggest that non-lethal doses of radiation can be used to make human tumors more amenable to attack by anti-tumor effector molecules and cells .
    OUTPUT:

agent
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.
    ###
    INPUT: BACKGROUND Death receptors ( DR ) of the TNF family function as anti-tumor immune effector molecules . Tumor cells , however , often exhibit DR-signaling resistance . Previous studies indicate that radiation can modify gene expression within tumor cells and increase tumor cell sensitivity to immune attack . The aim of this study is to investigate the synergistic effect of sub-lethal doses of ionizing radiation in sensitizing colorectal carcinoma cells to death receptor-mediated apoptosis . METHODOLOGY/PRINCIPAL FINDINGS The ability of radiation to modulate the expression of multiple death receptors ( Fas/CD95 , TRAILR1/DR4 , TRAILR2/DR5 , TNF-R1 and LTÎ²R ) was examined in colorectal tumor cells . The functional significance of sub-lethal doses of radiation in enhancing tumor cell susceptibility to DR-induced apoptosis was determined by in vitro functional sensitivity assays . The longevity of these changes and the underlying molecular mechanism of irradiation in sensitizing diverse colorectal carcinoma cells to death receptor-mediated apoptosis were also examined . We found that radiation increased surface expression of Fas , DR4 and DR5 but not LTÎ²R or TNF-R1 in these cells . Increased expression of DRs was observed 2 days post-irradiation and remained elevated 7-days post irradiation . Sub-lethal tumor cell irradiation alone exhibited minimal cell death , but effectively sensitized three of three colorectal carcinoma cells to both TRAIL and Fas-induced apoptosis , but not LTÎ²R-induced death . Furthermore , radiation-enhanced Fas and TRAIL-induced cell death lasted as long as 5-days post-irradiation . Specific analysis of intracellular sensitizers to apoptosis indicated that while radiation did reduce Bcl-X(L) and c-FLIP protein expression , this reduction did not correlate with the radiation-enhanced sensitivity to Fas and/or TRAIL mediated apoptosis among the three cell types . CONCLUSIONS/SIGNIFICANCE Irradiation of tumor cells can overcome Fas and TRAIL resistance that is long lasting . Overall , results of these investigations suggest that non-lethal doses of radiation can be used to make human tumors more amenable to attack by anti-tumor effector molecules and cells .
    OUTPUT:
