Zajac J D, Kearns A K, Skurat R M, Kronenberg H M, Bringhurst F R
Endocrine Unit, Massachusetts General Hospital, Boston 02114.
Mol Cell Endocrinol. 1992 Sep;87(1-3):69-77. doi: 10.1016/0303-7207(92)90234-w.
We employed a cyclic AMP-resistant subclone of UMR 106-01 osteoblastic osteosarcoma cells (UMR 4-7) with a regulated, dominant-negative mutation of cyclic AMP-dependent protein kinase (PK-A), to examine the mechanism(s) whereby parathyroid hormone (PTH) regulates growth of these cells. Expression of a transiently transfected CAT reporter gene controlled by the cAMP response element of the rat somatostatin gene ('SST-CAT') was used to monitor PK-A activation in intact cells. Agonist-stimulated SST-CAT expression was specific for agents known to activate adenylate cyclase, required an intact cAMP response element and was specifically blocked following induction of the mutant cAMP-resistant phenotype in UMR 4-7 cells. Inhibition of the proliferation of UMR 106-01 cells by PTH, which is mimicked by forskolin and 8-bromo-cAMP, was blocked completely in mutant cyclic AMP-resistant UMR 4-7 cells. We conclude that control of proliferation in UMR 106-01 cells by PTH involves the cAMP messenger system and requires activation of PK-A.
我们采用了UMR 106-01成骨细胞骨肉瘤细胞的一种抗环磷酸腺苷（cAMP）亚克隆（UMR 4-7），其具有环磷酸腺苷依赖性蛋白激酶（PK-A）的调控性显性负突变，以研究甲状旁腺激素（PTH）调节这些细胞生长的机制。由大鼠生长抑素基因的cAMP反应元件控制的瞬时转染氯霉素乙酰转移酶（CAT）报告基因（“SST-CAT”）的表达，用于监测完整细胞中的PK-A激活。激动剂刺激的SST-CAT表达对已知激活腺苷酸环化酶的试剂具有特异性，需要完整的cAMP反应元件，并且在UMR 4-7细胞中诱导出突变的抗cAMP表型后被特异性阻断。PTH对UMR 106-01细胞增殖的抑制作用（可被福斯可林和8-溴-cAMP模拟）在突变的抗环磷酸腺苷UMR 4-7细胞中被完全阻断。我们得出结论，PTH对UMR 106-01细胞增殖的控制涉及cAMP信使系统，并且需要PK-A的激活。
