title: Bifurcated converging pathways for high Ca2+- and TGFbeta-induced inhibition of growth of normal human keratinocytes.
abstract: Growth suppression of normal human keratinocytes by high Ca2+ or TGFbeta was shown to be mediated by p21WAF1/CIP1 and Sp1 [Pardali, K., et al. (2000) J. Biol. Chem. 275, 29244-29256; Santini, M. P., Talora, C., Seki, T., Bolgan, L. & Dotto, G. P. (2001) Proc. Nat. Acad. Sci. USA 98, 9575-9580; Al-Daraji, W. I., Grant, K. R., Ryan, K., Saxton, A., & Reynolds, N. J. (2002) J. Invest. Dermatol. 118, 779-788]. We previously demonstrated that S100C/A11 is a key mediator for growth inhibition of normal human epidermal keratinocytes (NHK) triggered by high Ca2+ or TGFbeta [Sakaguchi, M., et al. (2003) J. Cell Biol. 163, 825-835; Sakaguchi, M., et al. (2004) 164, 979-984]. On exposure of NHK cells to either agent, S100C/A11 is transferred to nuclei, where it induces p21WAF1/CIP1 through activation of Sp1/Sp3. In the present study, we found that high Ca2+ activated NFAT1 through calcineurin-dependent dephosphorylation. In growing NHK cells, Krueppel-like factor (KLF)16, a member of the Sp/KLF family, bound to the p21WAF1/CIP1 promoter and, thereby, inhibited the transcription of p21(WAF1/CIP1). Sp1 complexed with NFAT1 in high Ca2+-treated cells or with Smad3 in TGFbeta1-treated cells, but not Sp1 alone, replaced KLF16 from the p21WAF1/CIP1 promoter and transcriptionally activated the p21WAF1/CIP1 gene. Thus, high Ca2+ and TGFbeta1 have a common S100C/A11-mediated pathway in addition to a unique pathway (NFAT1-mediated pathway for high Ca2+ and Smad-mediated pathway for TGFbeta1) for exhibiting a growth inhibitory effect on NHK cells, and both pathways were shown to be indispensable for growth inhibition.
authors.affiliation: Departments of Cell Biology and Bacteriology, Okayama University Graduate School of Medicine and Dentistry, Shikata-chou, Okayama 700-8558, Japan.
authors.forename: Masakiyo
authors.initials: M
authors.lastname: Sakaguchi
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Sonegawa
authors.forename: Takamasa
authors.initials: T
authors.lastname: Nukui
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Sakaguchi
authors.forename: Masahiro
authors.initials: M
authors.lastname: Miyazaki
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Namba
authors.forename: Nam-Ho
authors.initials: NH
authors.lastname: Huh
mesh_terms: D002118:Calcium / Q000494:pharmacology*; D002478:Cells, Cultured; D006131:Growth Inhibitors / Q000494:pharmacology*; D006801:Humans; D015603:Keratinocytes / Q000187:drug effects / Q000378:metabolism*; D051741:Kruppel-Like Transcription Factors / Q000378:metabolism; D011401:Promoter Regions, Genetic; D015398:Signal Transduction; D016329:Sp1 Transcription Factor / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism*; D016212:Transforming Growth Factor beta / Q000494:pharmacology*
chemical_list: D006131:Growth Inhibitors; C431279:KLF16 protein, human; D051741:Kruppel-Like Transcription Factors; D016329:Sp1 Transcription Factor; D014157:Transcription Factors; D016212:Transforming Growth Factor beta; D002118:Calcium