IFN-beta pretreatment sensitizes human melanoma cells to TRAIL/Apo2 ligand-induced apoptosis

• Published in: The Journal of immunology (1950) 2002-07, Vol.169 (2), p.847-855
• Main Authors: Chawla-Sarkar, Mamta, Leaman, Douglas W, Jacobs, Barbara S, Borden, Ernest C
• Format: Article
• Language: English
• Subjects: Antineoplastic Agents - pharmacology; Apoptosis - immunology; Apoptosis Regulatory Proteins; Dose-Response Relationship, Immunologic; Drug Combinations; Drug Resistance; Drug Synergism; Growth Inhibitors - pharmacology; Humans; Hydrolysis; Immunization; Interferon-alpha - pharmacology; Interferon-beta - pharmacology; Ligands; Melanoma - immunology; Melanoma - metabolism; Melanoma - pathology; Melanoma - therapy; Membrane Glycoproteins - pharmacology; NF-kappa B - antagonists & inhibitors; NF-kappa B - metabolism; Proteins - antagonists & inhibitors; Proteins - metabolism; Receptors, Tumor Necrosis Factor - physiology; Signal Transduction - immunology; TNF-Related Apoptosis-Inducing Ligand; Tumor Cells, Cultured; Tumor Necrosis Factor-alpha - pharmacology; X-Linked Inhibitor of Apoptosis Protein
• ISSN: 0022-1767; 1550-6606
• DOI: 10.4049/jimmunol.169.2.847

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.