title: Acid sphingomyelinase activation requires caspase-8 but not p53 nor reactive oxygen species during Fas-induced apoptosis in human glioma cells.
abstract: During apoptosis of human glioma cells induced by anti-Fas antibody, ceramide formation with activation of acid, but not neutral sphingomyelinase (SMase), was observed. A potent inhibitor of acid SMase, SR33557, effectively inhibited ceramide formation and apoptosis. Fas-induced apoptosis and ceramide formation proceeded regardless of p53 status. The agents, which modify intracellular levels of reactive oxygen species (ROS) and reduced glutathione (GSH), failed to modulate Fas-induced acid SMase activation and apoptosis. Moreover, expression of functional p53 protein using a temperature-sensitive human p53val(138) induced ceramide generation by activation of neutral SMase but not acid SMase through ROS formation. Peptide inhibitors for caspases-8 (z-IETD-fmk) and -3 (z-DEVD-fmk) suppressed Fas-induced apoptosis. However, activation of acid SMase was inhibited only by z-IETD-fmk. Thus, ceramide generated by acid SMase may take a part in Fas-induced apoptosis of human glioma cells and acid SMase activation may be dependent on caspase-8 activation, but not on p53 nor ROS.
authors.affiliation: Department of Neurosurgery, Gifu University School of Medicine, Tsukasamachi-40, Gifu 500-8705, Japan. nohgeka@cc.gifu-u.ac.jp
authors.forename: Motoshi
authors.initials: M
authors.lastname: Sawada
authors.forename: Shigeru
authors.initials: S
authors.lastname: Nakashima
authors.forename: Tohru
authors.initials: T
authors.lastname: Kiyono
authors.forename: Jun
authors.initials: J
authors.lastname: Yamada
authors.forename: Shigeru
authors.initials: S
authors.lastname: Hara
authors.forename: Masanori
authors.initials: M
authors.lastname: Nakagawa
authors.forename: Jun
authors.initials: J
authors.lastname: Shinoda
authors.forename: Noboru
authors.initials: N
authors.lastname: Sakai
mesh_terms: D017209:Apoptosis; D053148:Caspase 3; D053181:Caspase 8; D053453:Caspase 9; D061945:Caspase Inhibitors; D020169:Caspases / Q000378:metabolism*; D002518:Ceramides / Q000378:metabolism; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005910:Glioma; D006801:Humans; D007212:Indolizines / Q000494:pharmacology; D009842:Oligopeptides / Q000494:pharmacology; D010627:Phenethylamines / Q000494:pharmacology; D017382:Reactive Oxygen Species / Q000378:metabolism*; D013108:Sphingomyelin Phosphodiesterase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*; D019014:fas Receptor / Q000378:metabolism*
chemical_list: D061945:Caspase Inhibitors; D002518:Ceramides; D015853:Cysteine Proteinase Inhibitors; D004791:Enzyme Inhibitors; D007212:Indolizines; D009842:Oligopeptides; D010627:Phenethylamines; D017382:Reactive Oxygen Species; D016159:Tumor Suppressor Protein p53; C403753:benzyloxycarbonyl-isoleucyl-glutamyl-threonyl-aspartic acid fluoromethyl ketone; D019014:fas Receptor; D013108:Sphingomyelin Phosphodiesterase; C505407:CASP3 protein, human; C505530:CASP8 protein, human; C506433:CASP9 protein, human; D053148:Caspase 3; D053181:Caspase 8; D053453:Caspase 9; D020169:Caspases; C059901:fantofarone