title: 12(S)-hydroxyeicosatetraenoic acid and 13(S)-hydroxyoctadecadienoic acid regulation of protein kinase C-alpha in melanoma cells: role of receptor-mediated hydrolysis of inositol phospholipids.
abstract: Protein kinase C (PKC) isoenzymes are essential components of cell signaling. In this study, we investigated the regulation of PKC-alpha in murine B16 amelanotic melanoma (B16a) cells by the monohydroxy fatty acids 12(S)-hydroxyeicosatetraenoic acid [12(S)-HETE] and 13(S)-hydroxyoctadecadienoic acid [13(S)-HODE]. 12(S)-HETE induced a translocation of PKC-alpha to the plasma membrane and focal adhesion plaques, leading to enhanced adhesion of B16a cells to the matrix protein fibronectin. However, 13(S)-HODE inhibited these 12(S)-HETE effects on PKC-alpha. A receptor-mediated mechanism of action for 12(S)-HETE and 13(S)-HODE is supported by the following findings. First, 12(S)-HETE triggered a rapid increase in cellular levels of diacylglycerol and inositol trisphosphate in B16a cells. 13(S)-HODE blocked the 12(S)-HETE-induced bursts of both second messengers. Second, the 12(S)-HETE-increased adhesion of B16a cells to fibronectin was sensitive to inhibition by a phospholipase C inhibitor and pertussis toxin. Finally, a high-affinity binding site (Kd = 1 nM) for 12(S)-HETE was detected in B16a cells, and binding of 12(S)-HETE to B16a cells was effectively inhibited by 13(S)-HODE (IC50 = 4 nM). In summary, our data provide evidence that regulation of PKC-alpha by 12(S)-HETE and 13(S)-HODE may be through a guanine nucleotide-binding protein-linked receptor-mediated hydrolysis of inositol phospholipids.
authors.affiliation: Department of Radiation Oncology, Wayne State University, Detroit, MI 48202, USA.
authors.forename: B
authors.initials: B
authors.lastname: Liu
authors.forename: W A
authors.initials: WA
authors.lastname: Khan
authors.forename: Y A
authors.initials: YA
authors.lastname: Hannun
authors.forename: J
authors.initials: J
authors.lastname: Timar
authors.forename: J D
authors.initials: JD
authors.lastname: Taylor
authors.forename: S
authors.initials: S
authors.lastname: Lundy
authors.forename: I
authors.initials: I
authors.lastname: Butovich
authors.forename: K V
authors.initials: KV
authors.lastname: Honn
mesh_terms: D019377:12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; D000818:Animals; D001665:Binding Sites; D001921:Brain / Q000201:enzymology; D002448:Cell Adhesion / Q000187:drug effects; D002460:Cell Line; D002462:Cell Membrane / Q000201:enzymology; D003600:Cytosol / Q000201:enzymology; D004075:Diglycerides / Q000378:metabolism; D005353:Fibronectins; D006868:Hydrolysis; D006893:Hydroxyeicosatetraenoic Acids / Q000378:metabolism / Q000494:pharmacology*; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism; D007527:Isoenzymes / Q000037:antagonists & inhibitors / Q000378:metabolism*; D007700:Kinetics; D008041:Linoleic Acids / Q000378:metabolism / Q000494:pharmacology*; D008546:Melanoma, Experimental / Q000378:metabolism*; D051379:Mice; D037342:Pertussis Toxin; D010716:Phosphatidylinositols / Q000378:metabolism*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000187:drug effects / Q000502:physiology*; D011994:Recombinant Proteins / Q000378:metabolism; D015398:Signal Transduction; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014407:Tumor Cells, Cultured; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
chemical_list: D004075:Diglycerides; D005353:Fibronectins; D006893:Hydroxyeicosatetraenoic Acids; D007527:Isoenzymes; D008041:Linoleic Acids; D010716:Phosphatidylinositols; D011956:Receptors, Cell Surface; D011994:Recombinant Proteins; D010566:Virulence Factors, Bordetella; C024348:13-hydroxy-9,11-octadecadienoic acid; D019377:12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; D015544:Inositol 1,4,5-Trisphosphate; D037342:Pertussis Toxin; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate