title: Activation of PKC but not of ERK is required for vitamin E-succinate-induced apoptosis of HL-60 cells.
abstract: Vitamin E-succinate (VES) induced HL-60 human leukemia cells to undergo apoptosis. Treatment with VES induced membrane translocation of Fas; cleavages of caspase-3, PARP, and lamin B; hypophosphorylation of retinoblastoma protein; and increase of p21(WAF1) protein level. During the induction of apoptosis, activity of PKC was gradually increased with downregulation of VES-induced ERK activity and accompanied by activation of caspase-3. Inhibition of PKC by GF109203X blocked VES-mediated membrane translocation of PKC-alpha and cleavage of caspase-3 cascade, resulting in prevention of VES-induced apoptosis. On the contrary, PKC activation by cotreatment with LPC or thapsigargin and VES synergistically increased VES-mediated apoptosis. However, inhibition of ERK activity by PD98059 showed no significant effect on VES-induced PKC activity and apoptosis. Taken together, our data suggest that VES induces activation of PKC and PKC-dependent hypophosphorylation of retinoblastoma protein, which results in induction of apoptosis, and that VES-induced early activation of ERK and ERK-dependent induction of p21(WAF1) are not required for apoptosis.
authors.affiliation: Department of Biology, College of Natural Sciences, Kyungpook National University, Taegu, 702-701, Korea.
authors.forename: O S
authors.initials: OS
authors.lastname: Bang
authors.forename: J H
authors.initials: JH
authors.lastname: Park
authors.forename: S S
authors.initials: SS
authors.lastname: Kang
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D002467:Cell Nucleus / Q000187:drug effects; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins / Q000378:metabolism; D004789:Enzyme Activation / Q000187:drug effects; D005419:Flavonoids / Q000494:pharmacology; D018922:HL-60 Cells; D006801:Humans; D007211:Indoles / Q000494:pharmacology; D007527:Isoenzymes / Q000037:antagonists & inhibitors / Q000378:metabolism*; D034921:Lamin Type B; D034882:Lamins; D008301:Maleimides / Q000494:pharmacology; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D009687:Nuclear Proteins / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism*; D051571:Protein Kinase C-alpha; D021381:Protein Transport / Q000187:drug effects; D016160:Retinoblastoma Protein / Q000378:metabolism; D019284:Thapsigargin / Q000494:pharmacology; D024505:Tocopherols; D020298:U937 Cells; D014810:Vitamin E / Q000031:analogs & derivatives* / Q000494:pharmacology*; D019014:fas Receptor / Q000378:metabolism
chemical_list: C493956:CDKN1A protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D005419:Flavonoids; D007211:Indoles; D007527:Isoenzymes; D034921:Lamin Type B; D034882:Lamins; D008301:Maleimides; D009687:Nuclear Proteins; D016160:Retinoblastoma Protein; D019014:fas Receptor; D014810:Vitamin E; D019284:Thapsigargin; D011065:Poly(ADP-ribose) Polymerases; C496628:PRKCA protein, human; D011493:Protein Kinase C; D051571:Protein Kinase C-alpha; D020928:Mitogen-Activated Protein Kinases; C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases; C070515:bisindolylmaleimide I; D024505:Tocopherols; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one