title: 1,25-Dihydroxyvitamin D3 increases bone alkaline phosphatase isoenzyme levels in human osteogenic sarcoma cells.
abstract: The specific activity of alkaline phosphatase was increased in two human osteogenic sarcoma cell lines, SAOS and TE85, after treatment with 1,25 dihydroxy-vitamin D3 (1,25(OH)2D3). Enzyme activity increased when the cells were incubated with concentrations of 1,25(OH)2D3 between 10(-9) and 10(-7) M and cell growth was not inhibited at these concentrations. The specific activity of alkaline phosphatase was 4- to 7-fold higher than that in the control cells after 5 to 7 days of continuous exposure to 1,25(OH)2D3. Immunochemical studies demonstrated that the enzyme from both control and 1,25(OH)2D3-treated cultures cross-reacted with antisera specific for the phosphatase isoenzyme produced by normal human bone, and did not cross-react with antisera specific for the placental alkaline phosphatase isoenzyme. The increased enzyme activity in cultures induced with 1,25(OH)2D3 correlated with an absolute increase in the number of bone-specific phosphatase molecules, as determined by radioimmunoassay. No effect on alkaline phosphatase activity was observed when the cells were treated with other vitamin D metabolites or with 5-bromo-2'-deoxyuridine. Comparative studies demonstrated that hydrocortisone, another steroid hormone, increased the phosphatase activity with a different time course than did 1,25(OH)2D3. High affinity cytoplasmic receptors for 1,25(OH)2D3 and hydrocortisone were found in the SAOS and TE85 cells.
mesh_terms: D000469:Alkaline Phosphatase / Q000276:immunology / Q000378:metabolism*; D001842:Bone and Bones / Q000201:enzymology*; D002117:Calcitriol / Q000494:pharmacology*; D002460:Cell Line; D000939:Epitopes / Q000276:immunology; D006801:Humans; D006854:Hydrocortisone / Q000494:pharmacology; D007118:Immunoassay; D007527:Isoenzymes / Q000378:metabolism*; D007700:Kinetics; D012516:Osteosarcoma / Q000201:enzymology* / Q000378:metabolism; D018167:Receptors, Calcitriol; D011965:Receptors, Glucocorticoid; D011987:Receptors, Steroid / Q000378:metabolism
chemical_list: D000939:Epitopes; D007527:Isoenzymes; D018167:Receptors, Calcitriol; D011965:Receptors, Glucocorticoid; D011987:Receptors, Steroid; C029360:hydrocortisone receptor; D000469:Alkaline Phosphatase; D002117:Calcitriol; D006854:Hydrocortisone