title: 20,23-dihydroxyvitamin D3, novel P450scc product, stimulates differentiation and inhibits proliferation and NF-kappaB activity in human keratinocytes.
abstract: We have examined effects of the 20,23-dihydroxyvitamin D3 (20,23(OH)2D3), on differentiation and proliferation of human keratinocytes and the anti-inflammatory potential of 20,23(OH)2D3 from its action on nuclear factor-kappaB (NF-kappaB). 20,23(OH)2D3 inhibited growth of keratinocytes with a potency comparable to that for 1,25-dihydroxyvitamin D3 (1,25(OH)2D3). Cell cycle analysis showed that this inhibition was associated with G1/G0 and G2/M arrests. 20,23(OH)2D3 stimulated production of involucrin mRNA and inhibited production of cytokeratin 14 mRNA in a manner similar to that seen for 1,25(OH)2D3. Flow cytometry showed that these effects were accompanied by increased involucrin protein expression, and an increase in the cell size and granularity. Silencing of the vitamin D receptor (VDR) by corresponding siRNA abolished the stimulatory effect on involucrin gene expression demonstrating an involvement of VDR in 20,23(OH)2D3 action. This mode of action was further substantiated by stimulation of CYP24 gene expression and stimulation of the CYP24 promoter-driven reporter gene activity. 20,23(OH)2D3 displayed several fold lower potency for induction of CYP24 gene expression than 1,25(OH)2D3. Finally, 20,23(OH)2D3 inhibited the transcriptional activity of NF-kappaB in keratinocytes as demonstrated by EMSA, NF-kappaB-driven reporter gene activity assays and measurements of translocation of p65 from the cytoplasm to the nucleus. These inhibitory effects were connected with stimulation of the expression of IkappaBalpha with subsequent sequestration of NF-kappaB in the cytoplasm and consequent attenuation of transcriptional activity. In summary, we have characterized 20,23(OH)2D3 as a novel secosteroidal regulator of keratinocytes proliferation and differentiation and a modifier of their immune activity.
authors.affiliation: Department for Pathology and Laboratory Medicine, Cancer Research Center, University of Tennessee Health Science Center, Memphis, Tennessee 38163, USA.
authors.forename: Zorica
authors.initials: Z
authors.lastname: Janjetovic
authors.forename: Robert C
authors.initials: RC
authors.lastname: Tuckey
authors.forename: Minh N
authors.initials: MN
authors.lastname: Nguyen
authors.forename: Edwin M
authors.initials: EM
authors.lastname: Thorpe
authors.forename: Andrzej T
authors.initials: AT
authors.lastname: Slominski
mesh_terms: D015090:25-Hydroxyvitamin D3 1-alpha-Hydroxylase / Q000378:metabolism; D000893:Anti-Inflammatory Agents / Q000378:metabolism / Q000494:pharmacology*; D001711:Biotransformation; D002117:Calcitriol / Q000378:metabolism / Q000494:pharmacology*; D002453:Cell Cycle / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects*; D049109:Cell Proliferation / Q000187:drug effects*; D002478:Cells, Cultured; D053493:Cholestanetriol 26-Monooxygenase / Q000378:metabolism; D002786:Cholesterol Side-Chain Cleavage Enzyme / Q000378:metabolism*; D004100:Dihydroxycholecalciferols / Q000378:metabolism / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004790:Enzyme Induction; D006801:Humans; D020672:I-kappa B Proteins / Q000378:metabolism; D053547:Keratin-14 / Q000235:genetics; D015603:Keratinocytes / Q000187:drug effects* / Q000201:enzymology; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D011498:Protein Precursors / Q000235:genetics; D034622:RNA Interference; D012333:RNA, Messenger / Q000378:metabolism; D018167:Receptors, Calcitriol / Q000235:genetics / Q000378:metabolism; D013250:Steroid Hydroxylases / Q000096:biosynthesis; D013997:Time Factors; D051996:Transcription Factor RelA / Q000378:metabolism; D014158:Transcription, Genetic; D014162:Transfection; D065668:Vitamin D3 24-Hydroxylase
chemical_list: C547379:20,23-dihydroxyvitamin D3; D000893:Anti-Inflammatory Agents; D004100:Dihydroxycholecalciferols; D020672:I-kappa B Proteins; C507540:KRT14 protein, human; D053547:Keratin-14; D016328:NF-kappa B; C000606204:NFKBIA protein, human; D011498:Protein Precursors; C498143:RELA protein, human; D012333:RNA, Messenger; D018167:Receptors, Calcitriol; D051996:Transcription Factor RelA; D000072000:NF-KappaB Inhibitor alpha; C032253:involucrin; D013250:Steroid Hydroxylases; C506831:CYP27A1 protein, human; D053493:Cholestanetriol 26-Monooxygenase; D065668:Vitamin D3 24-Hydroxylase; D015090:25-Hydroxyvitamin D3 1-alpha-Hydroxylase; D002786:Cholesterol Side-Chain Cleavage Enzyme; D002117:Calcitriol