title: 1,25-Dihydroxyvitamin D3 regulates the biosynthesis of osteopontin, a bone-derived cell attachment protein, in clonal osteoblast-like osteosarcoma cells.
abstract: We investigated the effects of 1,25-dihydroxyvitamin D3 on the synthesis of osteopontin, a phosphorylated cell attachment glycoprotein, in ROS 17/2.8 cells, a clonal osteoblast-like rat osteosarcoma cell line. We observed a dose dependent increase in uptake of [32PO4] into osteopontin secreted into the medium. An increased incorporation of [35S]-methionine into secreted osteopontin suggested the effect was that of increased protein biosynthesis. Using a radioimmunoassay we demonstrated a dose dependent increase in the amount of secreted osteopontin, an increase which could be blocked by Actinomycin D, in response to 1,25-dihydroxyvitamin D3. These results suggest that the hormonal form of vitamin D regulates the biosynthesis of osteopontin, possibly at the level of transcription.
mesh_terms: D000818:Animals; D002117:Calcitriol / Q000494:pharmacology*; D003609:Dactinomycin / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D008970:Molecular Weight; D010006:Osteoblasts / Q000187:drug effects / Q000378:metabolism*; D053495:Osteopontin; D012516:Osteosarcoma / Q000378:metabolism*; D010750:Phosphoproteins / Q000096:biosynthesis; D010766:Phosphorylation; D011863:Radioimmunoassay; D051381:Rats; D012795:Sialoglycoproteins / Q000096:biosynthesis*
chemical_list: D010750:Phosphoproteins; D012795:Sialoglycoproteins; C506897:Spp1 protein, rat; D053495:Osteopontin; D003609:Dactinomycin; D002117:Calcitriol