title: Staurosporine induces a sequential program of mouse keratinocyte terminal differentiation through activation of PKC isozymes.
abstract: Staurosporine (stsp) induces assembly of cornified envelopes in mouse keratinocyte cultures. To clarify whether this effect is the consequence of a coordinated differentiation program similar to that observed in epidermis, we assessed the expression of multiple differentiation-specific markers in stsp-treated keratinocytes. In medium containing 0.05 mM Ca2+, in which the basal cell phenotype is normally maintained, stsp induced dose-dependent increases in keratin 1, epidermal and keratinocyte transglutaminases, SPR-1, loricrin, and profilaggrin mRNA. Based on nuclear run-on analysis, stsp-mediated marker expression was found to be due at least in part to increased transcription. Since protein kinase C (PKC) activation is required for keratinocyte differentiation, we tested whether stsp influenced this signaling pathway. Stsp induced the translocation of multiple PKC isoforms from the cytosol to membrane and/or cytoskeletal fractions, inducing isozyme downregulation within 24 h. Moreover, AP-1 DNA binding activity was elevated in stsp-treated keratinocytes, consistent with the notion that this agent influences keratinocyte-specific gene expression via the PKC pathway. Stsp-mediated marker expression was inhibited by the PKC inhibitor GF 109203X. In cells pre-treated with bryostatin 1 to selectively down-modulate specific PKC isoforms, stsp-induced loricrin, filaggrin, and SPR-1 expression was suppressed when PKC alpha, epsilon, and/or delta were downregulated, suggesting that these isozymes may be necessary for marker expression in response to this agent. Thus, in addition to its effects on cornified envelope assembly, stsp induces a coordinate program of differentiation-specific keratinocyte gene expression that is mediated at least in part by the PKC signaling pathway.
authors.affiliation: Laboratory of Cellular Carcinogenesis and Tumor Promotion, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, U.S.A.
authors.forename: C
authors.initials: C
authors.lastname: Stanwell
authors.forename: M F
authors.initials: MF
authors.lastname: Denning
authors.forename: S E
authors.initials: SE
authors.lastname: Rutberg
authors.forename: C
authors.initials: C
authors.lastname: Cheng
authors.forename: S H
authors.initials: SH
authors.lastname: Yuspa
authors.forename: A A
authors.initials: AA
authors.lastname: Dlugosz
mesh_terms: D000470:Alkaloids / Q000494:pharmacology*; D000818:Animals; D001483:Base Sequence; D001693:Biological Transport, Active / Q000187:drug effects; D002118:Calcium / Q000494:pharmacology; D002454:Cell Differentiation / Q000187:drug effects; D017931:DNA Primers / Q000235:genetics; D015536:Down-Regulation / Q000187:drug effects; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D015870:Gene Expression / Q000187:drug effects; D007527:Isoenzymes / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D015603:Keratinocytes / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology*; D051379:Mice; D008969:Molecular Sequence Data; D011493:Protein Kinase C / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D019311:Staurosporine; D018808:Transcription Factor AP-1 / Q000378:metabolism; D011503:Transglutaminases / Q000235:genetics
chemical_list: D000470:Alkaloids; D017931:DNA Primers; D004791:Enzyme Inhibitors; D007527:Isoenzymes; D012333:RNA, Messenger; D018808:Transcription Factor AP-1; D011503:Transglutaminases; D011493:Protein Kinase C; D019311:Staurosporine; D002118:Calcium