title: IFN-beta pretreatment sensitizes human melanoma cells to TRAIL/Apo2 ligand-induced apoptosis.
abstract: All human melanoma cell lines (assessed by annexin V and TUNEL assays) were resistant to apoptosis induction by TRAIL/Apo2L protein. TRAIL/Apo2L activated caspase-8 and caspase-3, but subsequent apoptotic events such as poly(ADP-ribose) polymerase cleavage and DNA fragmentation were not observed. To probe the molecular mechanisms of cellular resistance to apoptosis, melanoma cell lines were analyzed for expression of apoptosis regulators (apoptotic protease-associated factor-1, FLIP, caspase-8, caspase-9, caspase-3, cellular inhibitor of apoptosis, Bcl-2, or Bax); no correlation was observed. TRAIL/Apo2L was induced in melanoma cell lines by IFN-beta and had been correlated with apoptosis induction. Because IFN-beta induced other gene products that have been associated with apoptosis, it was postulated that one or more IFN-stimulated genes might sensitize cells to TRAIL/Apo2L. Melanoma cell lines were treated with IFN-beta for 16-24 h before treatment with TRAIL/Apo2L. Regardless of their sensitivity to either cytokine alone, >30% of cells underwent apoptosis in response to the combined treatment. Induction of apoptosis by IFN-beta and TRAIL/Apo2L in combination correlated with synergistic activation of caspase-9, a decrease in mitochondrial potential, and cleavage of poly(ADP-ribose) polymerase. Cleavage of X-linked inhibitor of apoptosis following IFN-beta and TRAIL/Apo2L treatment was observed in sensitive WM9, A375, or WM3211 cells but not in resistant WM35 or WM164 cells. Thus, in vitro IFN-beta and TRAIL/Apo2L combination treatment had more potent apoptotic and anti-growth effects when compared with either cytokine alone in melanoma cells lines.
authors.affiliation: Center for Drug Discovery and Development, Taussig Cancer Center, Cleveland Clinic Foundation, Cleveland, OH 44195, USA.
authors.forename: Mamta
authors.initials: M
authors.lastname: Chawla-Sarkar
authors.forename: Douglas W
authors.initials: DW
authors.lastname: Leaman
authors.forename: Barbara S
authors.initials: BS
authors.lastname: Jacobs
authors.forename: Ernest C
authors.initials: EC
authors.lastname: Borden
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology; D017209:Apoptosis / Q000276:immunology*; D051017:Apoptosis Regulatory Proteins; D004306:Dose-Response Relationship, Immunologic; D004338:Drug Combinations; D004351:Drug Resistance; D004357:Drug Synergism; D006131:Growth Inhibitors / Q000494:pharmacology; D006801:Humans; D006868:Hydrolysis; D007114:Immunization; D016898:Interferon-alpha / Q000494:pharmacology; D016899:Interferon-beta / Q000494:pharmacology*; D008024:Ligands; D008545:Melanoma / Q000276:immunology* / Q000378:metabolism / Q000473:pathology* / Q000628:therapy; D008562:Membrane Glycoproteins / Q000494:pharmacology*; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000378:metabolism; D011506:Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D018124:Receptors, Tumor Necrosis Factor / Q000502:physiology; D015398:Signal Transduction / Q000276:immunology; D053221:TNF-Related Apoptosis-Inducing Ligand; D014407:Tumor Cells, Cultured; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*; D051636:X-Linked Inhibitor of Apoptosis Protein
chemical_list: D000970:Antineoplastic Agents; D051017:Apoptosis Regulatory Proteins; D004338:Drug Combinations; D006131:Growth Inhibitors; D016898:Interferon-alpha; D008024:Ligands; D008562:Membrane Glycoproteins; D016328:NF-kappa B; D011506:Proteins; D018124:Receptors, Tumor Necrosis Factor; D053221:TNF-Related Apoptosis-Inducing Ligand; C505653:TNFSF10 protein, human; D014409:Tumor Necrosis Factor-alpha; D051636:X-Linked Inhibitor of Apoptosis Protein; C496866:XIAP protein, human; D016899:Interferon-beta