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RhoA–ROCK and p38MAPK-MSK1 mediate vitamin D effects on gene expression, phenotype, and Wnt pathway in colon cancer cells
Correspondence to amunoz{at}iib.uam.es
The active vitamin D metabolite 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) inhibits proliferation and promotes differentiation of colon cancer cells through the activation of vitamin D receptor (VDR), a transcription factor of the nuclear receptor superfamily. Additionally, 1,25(OH)2D3 has several nongenomic effects of uncertain relevance. We show that 1,25(OH)2D3 induces a transcription-independent Ca2+ influx and activation of RhoA–Rho-associated coiled kinase (ROCK). This requires VDR and is followed by activation of the p38 mitogen-activated protein kinase (p38MAPK) and mitogen- and stress-activated kinase 1 (MSK1). As shown by the use of chemical inhibitors, dominant-negative mutants and small interfering RNA, RhoA–ROCK, and p38MAPK-MSK1 activation is necessary for the induction of CDH1/E-cadherin, CYP24, and other genes and of an adhesive phenotype by 1,25(OH)2D3. RhoA–ROCK and MSK1 are also required for the inhibition of Wnt–β-catenin pathway and cell proliferation. Thus, the action of 1,25(OH)2D3 on colon carcinoma cells depends on the dual action of VDR as a transcription factor and a nongenomic activator of RhoA–ROCK and p38MAPK-MSK1.
Abbreviations used in this paper: 1,25(OH)2D3, 1,25-dihydroxyvitamin D3; ATF1, activating transcription factor 1; CREB, cAMP response element-binding protein; DKK-1, dickkopf-1; DRB, 5,6-dichlorobenzimidazole riboside; ERK, extracellular signal-regulated kinase; MSK1, mitogen- and stress-activated kinase 1; OCN, osteocalcin; OPN, osteopontin; qRT-PCR, quantitative RT-PCR; PRK2, protein-related kinase 2; ROCK, Rho-associated coiled kinase; shRNA, small hairpin RNA; TCF, T cell factor; VDR, vitamin D receptor; WB, Western blotting.
© 2008 Ordóñez-Morán et al. This article is distributed under the terms of an Attribution–Noncommercial–Share Alike–No Mirror Sites license for the first six months after the publication date (see http://www.jcb.org/misc/terms.shtml). After six months it is available under a Creative Commons License (Attribution–Noncommercial–Share Alike 3.0 Unported license, as described at http://creativecommons.org/licenses/by-nc-sa/3.0/).
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