title: Differential effects of caspase inhibitors on TNF-induced necroptosis.
abstract: TNF has been reported to induce caspase-independent necroptosis in the presence of Z-VAD-fmk, a pan-caspase inhibitor. We examined whether necroptosis was induced by caspase inhibitors other than Z-VAD-fmk. TNF-induced necroptosis was detected in the presence of Z-DEVD-fmk, which is commonly used as a caspase-3-specific inhibitor, but not in the presence of Z-Asp-CH2-DCB, which was reported to be a pan-caspase inhibitor. TNF-induced caspase-3 activity was completely inhibited by Z-VAD-fmk, Z-DEVD-fmk, or Z-Asp-CH2-DCB. Although TNF-induced proteolytic activation of procaspase-3 was completely prevented by Z-VAD-fmk or Z-DEVD-fmk, the partial proteolysis of procaspase-3 was induced in the presence of Z-Asp-CH2-DCB. Furthermore, although TNF-induced proteolytic activation of procaspase-8 was completely inhibited by Z-VAD-fmk or Z-DEVD-fmk, the partial proteolysis of procaspase-8 to the p43/41 intermediate and p18 active fragment was detected in the presence of Z-Asp-CH2-DCB. The cleavage of RIP1, which plays a crucial role in TNF-induced necroptosis and is cleaved by caspase-8, was completely inhibited by Z-VAD-fmk or Z-DEVD-fmk, whereas the partial degradation of RIP1 was detected in the presence of Z-Asp-CH2-DCB. These results suggest that the partial activation of caspase-8 in the presence of Z-Asp-CH2-DCB may suppress TNF-induced necroptosis via the cleavage of RIP1, and also suggest that Z-Asp-CH2-DCB, but not Z-DEVD-fmk, may be used as a caspase-3-specific inhibitor in cells.
authors: Department of Internal Medicine, Osaka Dental University, 8-1 Kuzuhahanazonocho, Hirakata, Osaka 573-1121, Japan. sawai@cc.osaka-dent.ac.jp
authors: Hirofumi
authors: H
authors: Sawai
mesh_terms: D000590:Amino Acid Chloromethyl Ketones / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D001224:Aspartic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology; D053148:Caspase 3 / Q000378:metabolism*; D053181:Caspase 8 / Q000378:metabolism*; D061945:Caspase Inhibitors / Q000494:pharmacology*; D045744:Cell Line, Tumor; D006801:Humans; D009336:Necrosis / Q000201:enzymology*; D028861:Nuclear Pore Complex Proteins / Q000378:metabolism; D009842:Oligopeptides / Q000494:pharmacology*; D059748:Proteolysis; D016601:RNA-Binding Proteins / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
chemical_list: C119724:AGFG1 protein, human; D000590:Amino Acid Chloromethyl Ketones; D061945:Caspase Inhibitors; D028861:Nuclear Pore Complex Proteins; D009842:Oligopeptides; D016601:RNA-Binding Proteins; D014409:Tumor Necrosis Factor-alpha; C110772:benzoylcarbonyl-aspartyl-glutamyl-valyl-aspartyl-fluoromethyl ketone; C093260:benzyloxycarbonyl-Asp-CH2OC(O)-2,6-dichlorobenzene; C096713:benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone; D001224:Aspartic Acid; D053148:Caspase 3; D053181:Caspase 8