title: 12-O-tetradecanoyl phorbol 13-acetate, protein kinase C (PKC) activator, protects human leukemia HL-60 cells from taxol-induced apoptosis: possible role for extracellular signal-regulated kinase.
abstract: The purpose of this study was to evaluate whether the mitogen-activated protein kinase/extracellular signal-regulated kinase (MEK) signaling pathway contributes to 12-O-tertadecanoyl phorbol 13-acetate (TPA)-mediated protection from taxol-induced apoptosis of human leukemia HL-60 cells. Treatment of cells with taxol for 12 h resulted in apoptosis of HL-60 cells. TPA was protective against taxol-induced apoptosis and this anti-apoptotic effect was reversible when TPA was used in conjunction with staurosporine and H-7, PKC inhibitors, suggesting that TPA may protect HL-60 cells against taxol-induced apoptosis via the PKC-dependent pathway. Since TPA stimulates MEK signal transduction pathway in HL-60 cells, we postulated that MEK pathway may be playing a role in the ability of TPA to inhibit taxol-induced apoptosis. PD098059, a specific MEK kinase inhibitor, abolished the ability of TPA to inhibit taxol-induced apoptosis. These results suggest that activation of PKC in HL-60 cells confers protection against taxol-induced apoptosis and that MEK mediates anti-apoptotic signaling of PKC.
authors.affiliation: Department of Microbiology and Immunology and Medicinal Resources Research Center of Wonkwang University, Iksan, Chonbug, Korea.
authors.forename: H O
authors.initials: HO
authors.lastname: Pae
authors.forename: J C
authors.initials: JC
authors.lastname: Yoo
authors.forename: B M
authors.initials: BM
authors.lastname: Choi
authors.forename: E J
authors.initials: EJ
authors.lastname: Lee
authors.forename: Y S
authors.initials: YS
authors.lastname: Song
authors.forename: H T
authors.initials: HT
authors.lastname: Chung
mesh_terms: D000972:Antineoplastic Agents, Phytogenic / Q000037:antagonists & inhibitors* / Q000633:toxicity; D017209:Apoptosis / Q000187:drug effects*; D002470:Cell Survival / Q000187:drug effects; D053938:DNA Fragmentation / Q000187:drug effects; D015536:Down-Regulation / Q000187:drug effects; D020536:Enzyme Activators / Q000494:pharmacology*; D005110:Extracellular Space / Q000502:physiology; D018922:HL-60 Cells; D006801:Humans; D020935:MAP Kinase Signaling System / Q000187:drug effects / Q000502:physiology; D009707:Nucleosomes / Q000187:drug effects; D017239:Paclitaxel / Q000037:antagonists & inhibitors* / Q000633:toxicity; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D020536:Enzyme Activators; D009707:Nucleosomes; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate; D017239:Paclitaxel