ABSTRACT
Primary cultures of human bone and vascular cells respond to vitamin D treatment by modulation of cell proliferation measured by DNA synthesis (DNA) and energy metabolism measured by creatine kinase specific activity (CK) via binding to vitamin D receptors (VDR) which are expressed in these cells. Vitamin D compounds also modulate the response to estradiol-17ß (E2) and the expression mRNAs of estrogen receptors (ERα and ERß), VDR, 25-hydroxy vitamin D3 1-α hydroxylase (1OHase) and lipoxygenases (12LO and 15LO). We now compared our newly synthesized analog: 1α,25-dihydroxy-9-methylene-19-norvitamin D3 JK152 (JK), on bone and vascular cells compared to other analogs. Human bone cell line SaOS2 respond to JK by increased DNA and stimulated CK dose-dependently, similar to the less-calcemic analogs CB 1093 (CB) and EB 1089 (EB). JK also up-regulated the response to E2 in terms of DNA and CK. JK inhibited DNA synthesis and increased CK in primary human vascular smooth muscle cells (VSMC) dose-dependently similar to EB and CB. JK up regulated the response to E2 in terms of CK with no effect on DNA. JK similar to CB and EB stimulated mRNA expression of VDR and ERα, 12LO and 15LO, with no effect on ERß and 1OHase mRNA expression in SaOS2 measured by real time PCR. Similar treatments of VSMC with JK, CB and EB stimulated 12LO and 15LO, VDR and ERα mRNA expression with no effect on ERß and 1OHase mRNA expression. The results presented here demonstrate that the new vitamin D less-calcemic analog JK is similar to other analogs in its effects on human cultured cells and therefore may be used in combined hormone replacement treatment (HRT) both in vitro and in vivo.