Acquired resistance to TRAIL-induced apoptosis in human ovarian cancer cells is conferred by increased turnover of mature caspase-3.
Little is known on how cancer cells can acquire resistance to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). In this study, we established TRAIL-resistant cells from the TRAIL-sensitive human ovarian carcinoma cell line OVCAR3 to evaluate the potential mechanisms of acquired resistance to TRAIL. The selected resistant cells were cross-resistant to Fas ligand but remained sensitive to drug-induced apoptosis. Expression of TRAIL receptors was not altered in TRAIL-resistant OVCAR3 cells. Cleavage of caspase-8 and caspase-3 occurred in both TRAIL-resistant and TRAIL-sensitive cells. However, mature caspase-3 fragments were not detected by immunoblot in TRAIL-resistant cells and caspase-3 activity was significantly inhibited in these cells. The addition of proteasome inhibitors significantly increased TRAIL-induced apoptosis in resistant cells and enhanced the accumulation of mature caspase-3 fragments. Pretreatment with cycloheximide showed that active caspase-3 fragments have a high turnover rate in OVCAR3 R350 cells. X-linked inhibitor of apoptosis down-regulation by RNA interference also increased the accumulation of cleaved caspase-3 intermediates and resensitized TRAIL-resistant cells. Our findings show that altered turnover of mature caspase-3 may lead to acquired TRAIL resistance in ovarian cancer cells. Proteasome and X-linked inhibitor of apoptosis inhibitors could have a role in clinical situations to potentiate the cytotoxic effects of TRAIL in resistant tumor cells.
Lane
Denis
D
Département de Microbiologie et Infectiologie, Faculté de Médecine, Université de Sherbrooke, 3001, 12ième Avenue Nord, Sherbrooke, Quebec, Canada J1H 5N4.
Côté
Marceline
M
Grondin
Roxanne
R
Couture
Marie-Christine
MC
Piché
Alain
A
D017209:Apoptosis; D051017:Apoptosis Regulatory Proteins / Q000627:therapeutic use*; D053148:Caspase 3; D053181:Caspase 8; D061945:Caspase Inhibitors; D020169:Caspases / Q000378:metabolism*; D045744:Cell Line, Tumor; D003513:Cycloheximide / Q000494:pharmacology; D015536:Down-Regulation; D019008:Drug Resistance, Neoplasm; D005260:Female; D006801:Humans; D008562:Membrane Glycoproteins / Q000627:therapeutic use*; D010051:Ovarian Neoplasms / Q000188:drug therapy* / Q000201:enzymology; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D061988:Proteasome Inhibitors; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000235:genetics / Q000494:pharmacology; D018124:Receptors, Tumor Necrosis Factor / Q000378:metabolism; D053221:TNF-Related Apoptosis-Inducing Ligand; D014409:Tumor Necrosis Factor-alpha / Q000627:therapeutic use*; D051636:X-Linked Inhibitor of Apoptosis Protein / Q000235:genetics / Q000378:metabolism
D051017:Apoptosis Regulatory Proteins; D061945:Caspase Inhibitors; D008562:Membrane Glycoproteins; D061988:Proteasome Inhibitors; D011500:Protein Synthesis Inhibitors; D034741:RNA, Small Interfering; 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; D003513:Cycloheximide; D011065:Poly(ADP-ribose) Polymerases; C505407:CASP3 protein, human; C505530:CASP8 protein, human; D053148:Caspase 3; D053181:Caspase 8; D020169:Caspases