Cyclooxygenase-2 overexpression inhibits death receptor 5 expression and confers resistance to tumor necrosis factor-related apoptosis-inducing ligand-induced apoptosis in human colon cancer cells.
The inducible cyclooxygenase-2 (COX-2) gene regulates prostaglandin biosynthesis,is up-regulated in colorectal cancers, and can influence apoptotic susceptibility. We determined whether forced COX-2 expression modulates apoptosis induction by tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), a member of tumor necrosis factor ligand family, and examined determinants of the apoptotic pathway, including membrane death receptors (DR-4 and DR-5). HCT-15 colon cancer cells lacking endogenous COX-2 proteins were stably transfected with the COX-2 cDNA and incubated with TRAIL. Forced COX-2 expression significantly attenuated TRAIL-induced apoptosis and was associated with transcriptional repression of DR-5 and up-regulation of Bcl-2. COX-2 transfectants showed reduced DR-5 mRNA and protein expression as well as reduced caspase-8, caspase-3, and caspase-9 activation relative to parental cells. Sulindac sulfide treatment restored DR-5 expression and, when combined with TRAIL, reduced cell viability to a greater extent than did either drug alone. In summary, modulation of DR-5 and Bcl-2 levels by COX-2 attenuates TRAIL-induced apoptosis and represents a novel mechanism of intrinsic drug resistance in human colon cancer cells.
Tang
Ximing
X
Department of Gastrointestinal Medicine, University of Texas M.D. Anderson Cancer Center, Houston, Texas 77030, USA.
Sun
Yun Jie
YJ
Half
Elizabeth
E
Kuo
M Tien
MT
Sinicrope
Frank
F
D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology; D051017:Apoptosis Regulatory Proteins; D020169:Caspases / Q000378:metabolism; D003110:Colonic Neoplasms / Q000188:drug therapy / Q000201:enzymology* / Q000235:genetics / Q000473:pathology*; D051546:Cyclooxygenase 2; D019008:Drug Resistance, Neoplasm; D004789:Enzyme Activation; D006801:Humans; D007527:Isoenzymes / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D008565:Membrane Proteins; D011451:Prostaglandin-Endoperoxide Synthases / Q000096:biosynthesis* / Q000235:genetics; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand; D018124:Receptors, Tumor Necrosis Factor / Q000037:antagonists & inhibitors* / Q000096:biosynthesis / Q000378:metabolism; D053221:TNF-Related Apoptosis-Inducing Ligand; D014162:Transfection; D014407:Tumor Cells, Cultured; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors / Q000494:pharmacology*
D000894:Anti-Inflammatory Agents, Non-Steroidal; D051017:Apoptosis Regulatory Proteins; D007527:Isoenzymes; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand; D018124:Receptors, Tumor Necrosis Factor; D053221:TNF-Related Apoptosis-Inducing Ligand; C105190:TNFRSF10A protein, human; C505639:TNFRSF10B protein, human; C505653:TNFSF10 protein, human; D014409:Tumor Necrosis Factor-alpha; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases; D020169:Caspases