Induction of the c-jun proto-oncogene by a protein kinase C-dependent mechanism during exposure of human epidermal keratinocytes to ethanol.
The present work demonstrates that ethanol induces expression of the c-jun proto-oncogene in human keratinocytes. Increased c-jun mRNA levels were detectable at 1 hr of exposure to 1% ethanol and at 24 hr remained above that in control keratinocytes. An increase in c-jun expression was also detectable at ethanol concentrations of 0.1 and 0.5%. Similar findings were obtained for the related jun-B and c-fos early response genes. The results also demonstrate that ethanol exposure is associated with increases in protein kinase C activity in both the cytosol and membrane fractions. This increase was detectable at 5 min and maximal at 30-60 min. The finding that induction of c-jun expression by ethanol was inhibited by the isoquinolinesulfonamide derivative H7, but not by HA1004, suggested that this effect is mediated by protein kinase C. Furthermore, down-regulation of protein kinase C by prolonged exposure to 12-O-tetradecanoylphorbol-13-acetate was associated with a block in ethanol-induced c-jun expression. We also demonstrated that ethanol exposure is associated with rapid (5-30 min) increases in intracellular levels of diradylglycerol. Taken together, these findings demonstrate that the exposure of keratinocytes to ethanol results in the activation of protein kinase C and c-jun expression.
Kharbanda
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S
Laboratory of Clinical Pharmacology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115.
Nakamura
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T
Kufe
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D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D002478:Cells, Cultured; D004075:Diglycerides / Q000032:analysis; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation / Q000187:drug effects; D000431:Ethanol / Q000494:pharmacology*; D015870:Gene Expression / Q000187:drug effects; D006801:Humans; D007546:Isoquinolines / Q000494:pharmacology; D015603:Keratinocytes / Q000187:drug effects* / Q000378:metabolism; D010879:Piperazines / Q000494:pharmacology; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000090063:Proto-Oncogene Mas; D016755:Proto-Oncogene Proteins c-jun / Q000096:biosynthesis*; D011519:Proto-Oncogenes; D012333:RNA, Messenger / Q000096:biosynthesis / Q000302:isolation & purification; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D004075:Diglycerides; D007546:Isoquinolines; C000715470:MAS1 protein, human; D010879:Piperazines; D000090063:Proto-Oncogene Mas; D016755:Proto-Oncogene Proteins c-jun; D012333:RNA, Messenger; D000431:Ethanol; C035561:diarachidonyl diglyceride; D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate