Abstract
Intracellular activation of sphingomyelinase, leading to ceramide generation, and ICE-like proteases have been implicated in TNF and Fas-induced apoptosis, but the links between these intracellular apoptotic mediators remain undefined. We show here that a specific peptide inhibitor of the ICE-like protease CPP32/Yama (DEVD-CHO) blocks anti-Fas-induced apoptosis in Jurkat and U937 cells, while having no effect on TNF-induced apoptosis in U937 cells. This peptide also prevents ceramide accumulation induced by Fas engagement. Jurkat and U937 cells, as well as their mtDNA-depleted derived lines (rho degree cells), were sensitive to ceramide toxicity, which was not prevented by ICE-like protease inhibitors. These results, taken together, suggest that ICE-like protease activation is a prerequisite for ceramide generation and subsequent apoptosis, at least in the case of Fas-induced cell death.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Chloromethyl Ketones / chemistry
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Amino Acid Chloromethyl Ketones / pharmacology
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Amino Acid Sequence
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Apoptosis / drug effects*
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Apoptosis / physiology
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Caspase 3
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Caspases*
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Cell Line
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Ceramides / biosynthesis*
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Cysteine Endopeptidases / metabolism*
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Cysteine Proteinase Inhibitors / chemistry
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Cysteine Proteinase Inhibitors / pharmacology*
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DNA, Mitochondrial / metabolism
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Humans
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Molecular Sequence Data
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Oligopeptides / chemistry
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Oligopeptides / pharmacology
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Tumor Necrosis Factor-alpha / metabolism
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fas Receptor / metabolism*
Substances
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Amino Acid Chloromethyl Ketones
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Ceramides
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Cysteine Proteinase Inhibitors
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DNA, Mitochondrial
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N-acetyl-tyrosyl-valyl-alanyl-aspartyl chloromethyl ketone
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Oligopeptides
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Tumor Necrosis Factor-alpha
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acetyl-aspartyl-glutamyl-valyl-aspartal
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fas Receptor
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CASP3 protein, human
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Caspase 3
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Caspases
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Cysteine Endopeptidases