title: Protein kinase C agonist and antagonist effects in normal human epidermal keratinocytes.
abstract: Several lines of evidence implicate protein kinase C (PKC) in the development of basal cell and squamous cell carcinomas, tumors which originate from epidermal keratinocytes. To examine PKC in a model relevant to human skin, we exposed normal human epidermal keratinocytes (NHEK) in serum-free media to a variety of PKC agonists and antagonists. NHEK PKC activity increased up to 10-fold within the 1st hour of exposure to tetradecanoyl phorbol acetate (TPA), and gradually returned to control values within 72 h. TPA-induced PKC activity was enhanced by pretreatment of cultures with protein and RNA synthesis inhibitors. TPA-induced growth arrest and differentiation was antagonized by staurosporine. Down-regulation by bryostatin pretreatment blocked TPA-stimulated differentiation. Our overall conclusion is that activation of PKC in cultured human keratinocytes is required for differentiation. These results are crucial to the analysis of compounds suspected of promoting or inhibiting epidermal tumors.
authors.affiliation: Department of Dermatology, Columbia University, New York, NY 10032.
authors.forename: M S
authors.initials: MS
authors.lastname: Matsui
authors.forename: I
authors.initials: I
authors.lastname: Illarda
authors.forename: N
authors.initials: N
authors.lastname: Wang
authors.forename: V A
authors.initials: VA
authors.lastname: DeLeo
mesh_terms: D000470:Alkaloids / Q000494:pharmacology*; D000595:Amino Acid Sequence; D054713:Bryostatins; D002118:Calcium / Q000494:pharmacology; D002454:Cell Differentiation / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D016895:Culture Media, Serum-Free / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D004790:Enzyme Induction / Q000187:drug effects; D000078404:Epidermal Cells; D005050:Etretinate / Q000494:pharmacology; D006801:Humans; D015603:Keratinocytes / Q000187:drug effects* / Q000201:enzymology; D007783:Lactones / Q000494:pharmacology*; D018942:Macrolides; D008969:Molecular Sequence Data; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D019311:Staurosporine; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*
chemical_list: D000470:Alkaloids; D054713:Bryostatins; D016895:Culture Media, Serum-Free; D007783:Lactones; D018942:Macrolides; D011500:Protein Synthesis Inhibitors; C046785:bryostatin 1; D005050:Etretinate; D011493:Protein Kinase C; D019311:Staurosporine; D013755:Tetradecanoylphorbol Acetate; D002118:Calcium