Characteristics of selective activation of cyclic AMP-dependent protein kinase isoenzymes by calcitonin and prostaglandin E2 in human breast cancer cells.
Characteristics of selective activation of cyclic AMP-dependent protein kinase isoenzymes by calcitonin and prostaglandin E2 in human breast cancer cells.
复制标题
人乳腺癌细胞中降钙素和前列腺素E2选择性激活环AMP依赖性蛋白激酶同工酶的特征。
作者：
S. Livesey;G. Collier;J. Zajac;B. Kemp;T. Martin
已经在两种人乳腺癌细胞系 T47D 和 MCF 7 中研究了环 AMP 依赖性蛋白激酶同工酶对降钙素刺激的反应特征。这两种细胞系都具有降钙素受体、降钙素反应性腺苷酸环化酶以及环 AMP 依赖性蛋白激酶的两种同工酶（I 型和 II 型）。腺苷酸环化酶也对前列腺素 E2 做出反应。环AMP依赖性蛋白激酶同工酶的急性激活通过使用多个小阴离子交换柱方法的改进来确定[Livesey，Kemp，Re，Partridge＆Martin（1982）J.Biol。化学。 257、14983-14987]。对照实验表明提取后激活不会影响数据。降钙素引起 T 47D 细胞中同工酶 II 的快速、选择性激活，在 10(-10)M 时具有半最大反应，并持续至少 24 小时。在MCF 7 细胞中，降钙素还引起同工酶II 的高度选择性激活，在5 X 10(-11) M 时具有半最大响应，但该响应是短暂的，4-6 小时后恢复到基础同工酶活性。此时，进一步添加降钙素不会重新刺激环AMP依赖性激酶活性。在这两种细胞系中，降钙素处理均未导致同工酶 I 的激活。另一方面，前列腺素 E2（T 47D 细胞中腺苷酸环化酶唯一重要的替代激动剂）在这些细胞中同等程度地激活同工酶 I 和 II，这说明在一种细胞类型中激活腺苷酸环化酶的两种激素可能通过对蛋白激酶同工酶的选择性作用而发挥不同的作用。
The characteristics of the cyclic AMP-dependent protein kinase isoenzyme response to calcitonin stimulation have been studied in two human breast cancer cell lines, T47D and MCF 7. Both cell lines possess calcitonin receptors, a calcitonin-responsive adenylate cyclase and the two isoenzymes of the cyclic AMP-dependent protein kinase, types I and II. The adenylate cyclase also responds to prostaglandin E2. Acute activation of the cyclic AMP-dependent protein kinase isoenzymes was determined by using a modification of a multiple small anion exchange column method [Livesey, Kemp, Re, Partridge & Martin (1982) J. Biol. Chem. 257, 14983-14987]. Control experiments showed that post-extraction activation did not influence the data. Calcitonin caused a rapid, selective activation of isoenzyme II in the T 47D cells with half-maximal response at 10(-10)M, and persisting for at least 24h. In MCF 7 cells calcitonin also caused a highly selective activation of isoenzyme II with half-maximal response at 5 X 10(-11) M, but the response was transient with a return to basal isoenzyme activity by 4-6 h. At this time further addition of calcitonin did not restimulate the cyclic AMP-dependent kinase activity. In neither cell line did calcitonin treatment result in activation of isoenzyme I. Prostaglandin E2, on the other hand, the only significant alternative agonist of adenylate cyclase in T 47D cells, activated isoenzymes I and II to an equal extent in these cells, illustrating that two hormones activating adenylate cyclase in the one cell type might exert different effects by their selective actions upon protein kinase isoenzymes.