Role of protein kinase C and phosphatases in 12(S)-HETE-induced tumor cell cytoskeletal reorganization.
Adherent B16 amelanotic melanoma (B16a) cells exposed to fatty acid 12(S)-HETE, a lipoxygenase metabolite of arachidonic acid, demonstrated a gradual dissolution of stress fibers and bundling-together of vimentin. The 12(S)-HETE effects on tumor cell cytoskeleton appeared 5 min after treatment, became prominent approximately 15 min following stimulation, and generally disappeared by 30 min. Simultaneous treatment of cells with 12(S)-HETE and okadaic acid (OA) prevented disappearance of the 12(S)-HETE effects by 30 min. Quantitative double immunoblotting of actin and vimentin indicated that actin, but not vimentin, underwent a time-related depolymerization. On the other hand, enhanced phosphorylation of vimentin but not of actin was observed after 12(S)-HETE treatment. 12(S)-HETE-enhanced vimentin phosphorylation was abolished by protein kinase C (PKC) inhibitor calphostin C, thus suggesting the involvement of PKC.
Tang
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DG
Department of Radiation Oncology, Wayne State University, Detroit, MI 48202, USA.
Honn
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KV
D019377:12-Hydroxy-5,8,10,14-eicosatetraenoic Acid / Q000494:pharmacology*; D000199:Actins / Q000187:drug effects / Q000378:metabolism; D000818:Animals; D003599:Cytoskeleton / Q000187:drug effects / Q000502:physiology* / Q000648:ultrastructure; D004791:Enzyme Inhibitors / Q000494:pharmacology; D007700:Kinetics; D008546:Melanoma, Experimental / Q000503:physiopathology* / Q000648:ultrastructure; D051379:Mice; D009281:Naphthalenes / Q000494:pharmacology; D019319:Okadaic Acid / Q000494:pharmacology; D010749:Phosphoprotein Phosphatases / Q000378:metabolism*; D010766:Phosphorylation; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism*; D013997:Time Factors; D014407:Tumor Cells, Cultured; D014746:Vimentin / Q000187:drug effects / Q000378:metabolism
D000199:Actins; D004791:Enzyme Inhibitors; D009281:Naphthalenes; D014746:Vimentin; D019319:Okadaic Acid; D019377:12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; D011493:Protein Kinase C; D010749:Phosphoprotein Phosphatases; C058819:calphostin C