SIGNAL TRANSDUCTION EVENTS AND THE REGULATION OF CELL GROWTH

信号转导事件和细胞生长的调节

• 批准号: 3838098
• 负责人: J B TREPEL
• 金额: --
• 依托单位: DIVISION OF CANCER TREATMENT
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/3838098
• 关键词: biological signal transduction; calcium flux; cell growth regulation; clone cells; cyclic AMP; enzyme activity; enzyme induction /repression; gene expression; growth inhibitors; hormone related neoplasm /cancer; human tissue; lovastatin; neoplastic growth; neurotransmitter receptor; northern blottings; nucleotide analog; phospholipase C; prostate neoplasms; receptor coupling; transforming growth factors; tumor suppressor genes

This project is designed to increase our understanding of the biology of prostate cancer and to develop a new approach to the treatment of advanced prostatic cancer through the study of the signal transduction events regulating the growth of human prostate carcinoma cell lines. This work is currently focused on (1) effects of cAMP on growth and differentiation, (2) cytotoxicity through activation of P2-purinergic receptors, and (3) the anticancer activity of the HMG-CoA reductase inhibitor lovastatin. We have found that elevation of intracellular cAMP is highly growth-inhibitory to all prostate carcinoma cell lines tested. To examine the mechanism of cAMP action in prostate carcinoma cells we tested the effect of the cAMP analog dibutyryl cAMP on the regulation of the potent negative growth factor TGF-beta. DbcAMP selectively induced the secretion of TGF-beta2 and not TGF-beta1 by prostate carcinoma cells. This TGF-beta2 was shown to be bioactive using the CCL-64 mink lung cell assay. Northern analysis showed that dbcAMP induced an increase in the five characteristic TGF-beta2 transcripts. Thus dbcAMP induces the expression of bioactive TGF-beta2 by prostate carcinoma cells, suggesting a new approach to the treatment of prostate cancer and a new molecular mechanism of cAMP action. P2-purinergic receptor studies demonstrated that androgen-independent prostate carcinoma cells express P2-purinergic receptors that are coupled to phospholipase C activation, acute Ca2+ mobilization, prolonged cytoplasmic and nuclear Ca2+ oscillations, growth arrest, and an increased rate of cell death. In contrast, androgen-sensitive cells have surface P2 receptors that are uncoupled from phospholipase C, Ca2+ mobilization and growth arrest. In collaboration with the Molecular Pathophysiology Branch we found that the androgen-sensitive cells lack expression of G protein alpha subunits that have been shown to couple to phospholipase C. These data strongly implicate phospholipase C activation and prolonged Ca2+ mobilization in the growth-inhibitory effect of P2 agonists, and provide a molecular mechanism for the uncoupling of the P2 receptor in androgen-sensitive cells. Studies with the HMG-CoA reductase inhibitor lovastatin showed that lovastatin is cytotoxic to human prostate carcinoma cells. We found that lovastatin treatment results in marked deregulation of TGF-beta2 mRNA synthesis and in deregulation of protein expression of the tumor suppressor gene product pRB.

这个项目旨在增加我们对生物学的理解， 前列腺癌，并开发一种新的方法来治疗 晚期前列腺癌的信号转导研究 调节人前列腺癌细胞系生长的事件。 这项工作目前集中在（1）cAMP对生长的影响， 分化，（2）通过激活P2-嘌呤能的细胞毒性 受体，和（3）HMG-CoA还原酶的抗癌活性 抑制剂洛伐他汀。 我们发现细胞内cAMP的升高 对所有测试的前列腺癌细胞系都是高度生长抑制的。 为了研究前列腺癌细胞中cAMP作用的机制，我们 测试了cAMP类似物二丁酰cAMP对调节 强大的负生长因子TGF-β DbcAMP选择性诱导 前列腺癌细胞分泌TGF-β 2而不是TGF-β 1。 使用CCL-64貂肺细胞显示TGF-β 2具有生物活性 比色法 北方分析表明，dbcAMP诱导的增加， 五种特征性TGF-β 2转录物。 因此，dbcAMP诱导 前列腺癌细胞表达生物活性TGF-β 2，提示 一种治疗前列腺癌的新方法， cAMP作用机制。 P2-嘌呤能受体研究表明， 雄激素非依赖性前列腺癌细胞表达P2-嘌呤能 与磷脂酶C激活偶联的受体，急性Ca 2 + 动员，延长细胞质和细胞核Ca 2+振荡，生长 逮捕，并增加细胞死亡率。 与此相反， 雄激素敏感细胞具有未偶联的表面P2受体 从磷脂酶C，Ca 2+动员和生长停滞。 在 与分子病理生理学分支合作，我们发现， 雄激素敏感细胞缺乏G蛋白α亚基的表达， 已经显示与磷脂酶C偶联。这些数据强烈 磷脂酶C激活和延长的Ca 2+动员， P2激动剂的生长抑制作用，并提供了一种分子 雄激素敏感性前列腺癌P2受体解偶联的机制 细胞 HMG-CoA还原酶抑制剂洛伐他汀的研究显示， 洛伐他汀对人前列腺癌细胞具有细胞毒性。 我们发现 洛伐他汀治疗导致TGF-β 2显著失调 mRNA合成与肿瘤蛋白表达失调 抑制基因产物pRB。