Characterization of an osteoblast-like clonal cell line which responds to both parathyroid hormone and calcitonin.
The clonal cell line UMR 106, which was originally derived from a rat transplantable osteogenic sarcoma with an osteoblastic phenotype, was subcloned after the emergence of a calcitonin-responsive adenylate cyclase was noted in late passages. Detailed studies on the stimulation of adenylate cyclase and activation profile of the cyclic AMP-dependent protein kinase isoenzymes in response to parathyroid hormone (PTH) and salmon calcitonin (SCT) were conducted on two subclones (UMR 106-01 and UMR 106-06). Both subclones responded in an identical manner to PTH, which stimulated adenylate cyclase and activated both isoenzyme I and isoenzyme II of cyclic AMP-dependent protein kinase. In contrast, only UMR 106-06 cells responded to calcitonin. At 3 X 10(-8)M SCT, there was a sevenfold stimulation of adenylate cyclase, 84% activation of isoenzyme I, and 44% activation of isoenzyme II. The activation profiles of the isoenzymes to PTH and SCT in UMR 106-06 were similar. Furthermore, their response to SCT correlates with the presence of specific, saturable binding of 125I-labeled SCT. Binding parameters indicate apparent Kd = 0.8 nM and 6,000 receptors/cell. These data point to a significant phenotypic change having taken place in this clonal cell line with prolonged maintenance in culture, with the emergence of a calcitonin receptor linked to adenylate cyclase and protein kinase activation.
D000135:Acid Phosphatase / Q000032:analysis; D000262:Adenylyl Cyclases / Q000032:analysis; D000469:Alkaline Phosphatase / Q000032:analysis; D000818:Animals; D002116:Calcitonin / Q000494:pharmacology; D002460:Cell Line; D002999:Clone Cells / Q000201:enzymology; D004789:Enzyme Activation / Q000187:drug effects; D007527:Isoenzymes / Q000032:analysis; D010006:Osteoblasts / Q000187:drug effects / Q000201:enzymology*; D012516:Osteosarcoma / Q000473:pathology*; D010281:Parathyroid Hormone / Q000494:pharmacology; D010641:Phenotype; D011494:Protein Kinases / Q000032:analysis; D051381:Rats
D007527:Isoenzymes; D010281:Parathyroid Hormone; D002116:Calcitonin; D011494:Protein Kinases; D000469:Alkaline Phosphatase; D000135:Acid Phosphatase; D000262:Adenylyl Cyclases