Differential induction of apoptosis by tumor necrosis factor-related apoptosis-inducing ligand in human ovarian carcinoma cells.
OBJECTIVE
In this study, we examine the sensitivity of a panel of ovarian carcinoma cells, which includes four primary ovarian cancer cell samples, and four normal ovarian epithelium samples to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). We also examine the intracellular regulation of TRAIL-mediated apoptosis.


METHODS
The sensitivity to TRAIL was determined by short-term survival assays on seven ovarian carcinoma cell lines, four primary samples of ovarian cancer, and four normal ovarian epithelium samples. We assessed the activation of the apoptotic pathway in TRAIL-resistant and -sensitive tumor cells. The expression of TRAIL receptors was determined by flow cytometry. The protein expression of FADD, XIAP, caspase-8, caspase-3, BAX, and c-FLIP were determined by immunoblot analyses.


RESULTS
We show that ovarian cancer cells display variable sensitivity to TRAIL-induced apoptosis although most cell lines have similar sensitivity to cisplatin. Normal ovarian epithelium samples were mostly sensitive to TRAIL. In sensitive cells, TRAIL induced caspase-8-dependent apoptosis, which subsequently led to activation of caspase-3. Both sensitive and resistant cells expressed caspase-8, caspase-3, FADD, XIAP, and c-FLIP at similar levels. A significant enhancement in cell death was observed in TRAIL-resistant cells when c-FLIP(L) levels were downregulated by RNA interference.


CONCLUSIONS
These data suggest that sensitivity to TRAIL and chemotherapy does not necessarily correlate in human ovarian cancer cells. Cancerous cells isolated from patients with ovarian cancer show variable sensitivity to TRAIL but most normal ovarian epithelial cells are sensitive. In human ovarian cancer cells, c-FLIP(L) may participate to the regulation of the TRAIL signaling cascade.
Lane
Denis
D
Département de Microbiologie et Infectiologie, Faculté de Médecine, Université de Sherbrooke, 3001 Sherbrooke, Canada J1H 5N1.
Cartier
Andréanne
A
L'Espérance
Sylvain
S
Côté
Marceline
M
Rancourt
Claudine
C
Piché
Alain
A
D017209:Apoptosis / Q000187:drug effects*; D051017:Apoptosis Regulatory Proteins; D053446:CASP8 and FADD-Like Apoptosis Regulating Protein; D002352:Carrier Proteins / Q000096:biosynthesis; D053148:Caspase 3; D053181:Caspase 8; D020169:Caspases / Q000378:metabolism; D045744:Cell Line, Tumor; D004354:Drug Screening Assays, Antitumor; D004789:Enzyme Activation; D005260:Female; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D008562:Membrane Glycoproteins / Q000494:pharmacology*; D010051:Ovarian Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D014176:Protein Biosynthesis; D011506:Proteins; D018124:Receptors, Tumor Necrosis Factor / Q000096:biosynthesis / Q000378:metabolism; D011994:Recombinant Proteins / Q000494:pharmacology; D053221:TNF-Related Apoptosis-Inducing Ligand; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*; D051636:X-Linked Inhibitor of Apoptosis Protein
D051017:Apoptosis Regulatory Proteins; D053446:CASP8 and FADD-Like Apoptosis Regulating Protein; C506386:CFLAR protein, human; D002352:Carrier Proteins; D047908:Intracellular Signaling Peptides and Proteins; D008562:Membrane Glycoproteins; D011506:Proteins; D018124:Receptors, Tumor Necrosis Factor; D011994:Recombinant Proteins; 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; C505407:CASP3 protein, human; C505530:CASP8 protein, human; D053148:Caspase 3; D053181:Caspase 8; D020169:Caspases