TRAIL-induced apoptosis of human melanoma cells involves activation of caspase-4.
Although it is conventionally regarded as an inflammatory caspase, recent studies have shown that caspase-4 plays a role in induction of apoptosis by endoplasmic reticulum (ER) stress. We report here that activation of caspase-4 is also involved in induction of apoptosis by TNF-related apoptosis-inducing ligand (TRAIL) in human melanoma cells. Treatment with TRAIL resulted in activation of caspase-4. This appeared to be mediated by caspase-3, in that caspase-4 was activated later than caspase-8, -9, and -3, and that inhibition of caspase-3 blocked TRAIL-induced caspase-4 activation. Notably, TRAIL triggered ER stress in melanoma cells as shown by up-regulation of the GRP78 protein and the spliced form of XBP-1 mRNA. This seemed to be necessary for activation of caspase-4, as activation of caspase-3 by agents that did not trigger ER stress did not cause activation of caspase-4. Importantly, inhibition of caspase-4 also partially blocked caspase-3 activation, suggesting that activation of caspase-4 may be positive feed-back mechanism to further enhance caspase-3 activation. Collectively, these results show that activation of caspase-4 contributes to TRAIL-induced apoptosis and is associated with induction of ER stress by TRAIL in melanoma cells, and may have important implications for improving therapeutic efficacies of TRAIL in melanoma.
Mao
Zhi Gang
ZG
Immunology and Oncology Unit, Newcastle Misericordiae Hospital, Room 443, David Maddison Clinical Sciences Building, Cnr. King and Watt Streets, Newcastle, NSW, 2300, Australia.
Jiang
Chen Chen
CC
Yang
Fan
F
Thorne
Rick F
RF
Hersey
Peter
P
Zhang
Xu Dong
XD
D000818:Animals; D017209:Apoptosis; D015153:Blotting, Western; D053148:Caspase 3 / Q000378:metabolism; D061945:Caspase Inhibitors; D053471:Caspases, Initiator / Q000378:metabolism*; D045744:Cell Line, Tumor; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000378:metabolism; D000091342:Endoplasmic Reticulum Chaperone BiP; D004789:Enzyme Activation; D015870:Gene Expression; D006360:Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D008545:Melanoma / Q000378:metabolism* / Q000473:pathology*; D051379:Mice; D012326:RNA Splicing; D034741:RNA, Small Interfering; D011817:Rabbits; D011994:Recombinant Proteins; D000071701:Regulatory Factor X Transcription Factors; D013312:Stress, Physiological; D053221:TNF-Related Apoptosis-Inducing Ligand / Q000378:metabolism* / Q000494:pharmacology; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D015854:Up-Regulation; D000071717:X-Box Binding Protein 1
D061945:Caspase Inhibitors; D004268:DNA-Binding Proteins; D000091342:Endoplasmic Reticulum Chaperone BiP; C000717247:HSPA5 protein, human; D006360:Heat-Shock Proteins; C000717248:Hspa5 protein, mouse; D034741:RNA, Small Interfering; D011994:Recombinant Proteins; D000071701:Regulatory Factor X Transcription Factors; D053221:TNF-Related Apoptosis-Inducing Ligand; C505653:TNFSF10 protein, human; D014157:Transcription Factors; D000071717:X-Box Binding Protein 1; C000605543:XBP1 protein, human; C000605544:Xbp1 protein, mouse; C093516:CASP4 protein, human; D053148:Caspase 3; D053471:Caspases, Initiator