title: Sequential operation of ceramide synthesis and ICE cascade in CPT-11-initiated apoptotic death signaling.
abstract: The chemotherapeutic agent CPT-11 induced apoptotic cell death in mouse fibroblast 4B1 cells. To examine the intracellular apoptotic death signal initiated by CPT-11, ceramide synthesis and the ICE cascade were analyzed. CPT-11-initiated cytolytic activity was prevented by both caspase inhibitors YVAD-CHO and DEVD-CHO, or ceramide synthesis inhibitor fumonisin B1, and accelerated by sphingomyelin, suggesting the direct involvement of ceramide synthesis and the interleukin 1-beta converting enzyme (ICE) cascade. In addition, apoptosis was induced by both native and synthesized ceramide and prevented by YVAD-CHO and DEVD-CHO, suggesting the possible involvement of ceramide in ICE cascade operation. To directly demonstrate whether ceramide synthesis operates the ICE cascade, proteolytic activity of ICE- or CPP32-like proteinase was analyzed. ICE-like proteinase activity was prevented by fumonisin B1 and YVAD-CHO, but not by DEVD-CHO. In contrast, fumonisin B1, YVAD-CHO, and DEVD-CHO all prevented CPP32-like proteinase activity. These results suggest that ceramide synthesis acts as a dominant regulator in CPT-11-initiated death signaling and sequentially operates the ICE cascade.
authors.affiliation: Drug Safety Research Laboratory, Daiichi Pharmaceutical Co., Ltd., Tokyo R&D Center, Edogawa-ku, Japan. LEBOO373@niftyserve.or.jp
authors.forename: A
authors.initials: A
authors.lastname: Suzuki
authors.forename: M
authors.initials: M
authors.lastname: Iwasaki
authors.forename: M
authors.initials: M
authors.lastname: Kato
authors.forename: N
authors.initials: N
authors.lastname: Wagai
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D002166:Camptothecin / Q000031:analogs & derivatives* / Q000494:pharmacology; D002264:Carboxylic Acids / Q000494:pharmacology; D020170:Caspase 1; D002478:Cells, Cultured; D002518:Ceramides / Q000096:biosynthesis*; D003546:Cysteine Endopeptidases / Q000378:metabolism*; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005347:Fibroblasts / Q000166:cytology; D037341:Fumonisins; D000077146:Irinotecan; D051379:Mice; D009842:Oligopeptides / Q000494:pharmacology; D015398:Signal Transduction; D059004:Topoisomerase I Inhibitors
chemical_list: D002264:Carboxylic Acids; D002518:Ceramides; D015853:Cysteine Proteinase Inhibitors; D004791:Enzyme Inhibitors; D037341:Fumonisins; D009842:Oligopeptides; D059004:Topoisomerase I Inhibitors; C099158:acetyl-aspartyl-glutamyl-valyl-aspartal; C096429:L 709049; C056933:fumonisin B1; D000077146:Irinotecan; D003546:Cysteine Endopeptidases; D020170:Caspase 1; D002166:Camptothecin