Affinity of 22-oxa-1,25(OH)2D3 for 1,25-dihydroxyvitamin D receptor and its effects on the synthesis of osteocalcin in human osteosarcoma cells.

A new 1,25-dihydroxyvitamin D3 analog, 22-oxa-1,25(OH)2D3, which may have pharmaceutical use, e.g., in the treatment of psoriasis, was studied using cultured MG-63 human osteosarcoma cells. We found that the new compound binds to 1,25-dihydroxyvitamin D receptors and regulates receptor mRNA levels like the natural ligand. Our results also indicate that 22-oxa-1,25(OH)2D3 induces the synthesis of osteocalcin and the activity of alkaline phosphatase in MG-63 cells through a receptor-mediated process identically with 1,25(OH)2D3.