title: P53 mediates ceramide-induced apoptosis in SKN-SH cells.
abstract: Ceramide induces apoptotic cell death in a dose- and time-dependent manner in neuroblastoma SKN-SH cells. Pretreatment with caspase inhibitors blocks cell death, suggesting that a set of caspase activities including caspase 1, as well as caspase 3, are involved in ceramide-induced apoptosis in SKN-SH cells. Treatment with a caspase inhibitor 3 h after ceramide addition did not inhibit cell death, although caspase activity was substantially reduced. Ceramide-induced apoptosis is accompanied by accumulation of p53 followed by an increase of Bax and decrease of Bcl-2 levels. Inhibition of p53 expression with p53 antisense oligonucleotides inhibits apoptosis and prevents the increase in Bax and decrease in Bcl-2. Furthermore, pretreatment with p53 antisense oligonucleotides markedly inhibits the induction of caspase activity. These results suggest that p53 regulates the ratio Bcl-2/Bax and the expression/activation of caspases during ceramide-induced apoptosis in SKN-SH cells. Caspase inhibition did not alter the expression of p53, Bcl-2 and Bax. Thus ceramide-induced reduction in the Bcl-2/Bax ratio, increase in caspase activity, and apoptosis is dependent upon increases in cellular p53 levels which play a critical role in the regulation of apoptotic cell death.
authors.affiliation: Department of Anatomy, College of Medicine, BioGrand Inc., MRC, Chung-Ang University, Seoul, Korea 156-756.
authors.forename: Sung Su
authors.initials: SS
authors.lastname: Kim
authors.forename: Hee-Sun
authors.initials: HS
authors.lastname: Chae
authors.forename: Jae-Hyung
authors.initials: JH
authors.lastname: Bach
authors.forename: Myoung Woo
authors.initials: MW
authors.lastname: Lee
authors.forename: Kyung Yong
authors.initials: KY
authors.lastname: Kim
authors.forename: Won Bok
authors.initials: WB
authors.lastname: Lee
authors.forename: Young-Min
authors.initials: YM
authors.lastname: Jung
authors.forename: Joseph V
authors.initials: JV
authors.lastname: Bonventre
authors.forename: Yoo-Hun
authors.initials: YH
authors.lastname: Suh
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D061945:Caspase Inhibitors; D020169:Caspases / Q000378:metabolism; D002518:Ceramides / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D009447:Neuroblastoma / Q000235:genetics / Q000378:metabolism* / Q000473:pathology*; D016376:Oligonucleotides, Antisense; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D013997:Time Factors; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism*; D051028:bcl-2-Associated X Protein
chemical_list: C494826:BAX protein, human; D061945:Caspase Inhibitors; D002518:Ceramides; D004791:Enzyme Inhibitors; D016376:Oligonucleotides, Antisense; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D016159:Tumor Suppressor Protein p53; D051028:bcl-2-Associated X Protein; D020169:Caspases