PT  - JOURNAL ARTICLE
AU  - Robert C. Tuckey
AU  - Wei Li
AU  - Haleem Z. Shehabi
AU  - Zorica Janjetovic
AU  - Minh N. Nguyen
AU  - Tae-Kang Kim
AU  - Jianjun Chen
AU  - Danielle E. Howell
AU  - Heather A. E. Benson
AU  - Trevor Sweatman
AU  - Donna M. Baldisseri
AU  - Andrzej Slominski
TI  - Production of 22-Hydroxy Metabolites of Vitamin D<sub>3</sub> by Cytochrome P450scc (CYP11A1) and Analysis of Their Biological Activities on Skin Cells
AID  - 10.1124/dmd.111.040071
DP  - 2011 Sep 01
TA  - Drug Metabolism and Disposition
PG  - 1577--1588
VI  - 39
IP  - 9
4099  - http://dmd.aspetjournals.org/content/39/9/1577.short
4100  - http://dmd.aspetjournals.org/content/39/9/1577.full
SO  - Drug Metab Dispos2011 Sep 01; 39
AB  - Cytochrome P450scc (CYP11A1) can hydroxylate vitamin D3, producing 20S-hydroxyvitamin D3 [20(OH)D3] and 20S,23-dihydroxyvitamin D3 [20,23(OH)2D3] as the major metabolites. These are biologically active, acting as partial vitamin D receptor (VDR) agonists. Minor products include 17-hydroxyvitamin D3, 17,20-dihydroxyvitamin D3, and 17,20,23-trihydroxyvitamin D3. In the current study, we have further analyzed the reaction products from cytochrome P450scc (P450scc) action on vitamin D3 and have identified two 22-hydroxy derivatives as products, 22-hydroxyvitamin D3 [22(OH)D3] and 20S,22-dihydroxyvitamin D3 [20,22(OH)2D3]. The structures of both of these derivatives were determined by NMR. P450scc could convert purified 22(OH)D3 to 20,22(OH)2D3. The 20,22(OH)2D3 could also be produced from 20(OH)D3 and was metabolized to a trihydroxyvitamin D3 product. We compared the biological activities of these new derivatives with those of 20(OH)D3, 20,23(OH)2D3, and 1α,25-dihydroxyvitamin D3 [1,25(OH)2D3]. 1,25(OH)2D3, 20(OH)D3, 22(OH)D3, 20,23(OH)2D3, and 20,22(OH)2D3 significantly inhibited keratinocyte proliferation in a dose-dependent manner. The strongest inducers of involucrin expression (a marker of keratinocyte differentiation) were 20,23(OH)2D3, 20,22(OH)2D3, 20(OH)D3, and 1,25(OH)2D3, with 22(OH)D3 having a heterogeneous effect. Little or no stimulation of CYP24 mRNA expression was observed for all the analogs tested except for 1,25(OH)2D3. All the compounds stimulated VDR translocation from the cytoplasm to the nucleus with 22(OH)D3 and 20,22(OH)2D3 having less effect than 1,25(OH)2D3 and 20(OH)D3. Thus, we have identified 22(OH)D3 and 20,22(OH)2D3 as products of CYP11A1 action on vitamin D3 and shown that, like 20(OH)D3 and 20,23(OH)2D3, they are active on keratinocytes via the VDR, however, showing a degree of phenotypic heterogeneity in comparison with other P450scc-derived hydroxy metabolites of vitamin D3.