REGULATION OF HORMONE RESPONSIVENESS DURING CELLULAR DIFFERENTIATION

细胞分化过程中激素反应的调节

• 批准号: 3940229
• 负责人: M C LIN
• 金额: --
• 依托单位: NATIONAL INSTITUTE OF DIABETES AND DIGESTIVE AND KIDNEY DISEASES
• 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/3940229
• 关键词: 3'5' cyclic nucleotide phosphodiesterase; cell differentiation; cell growth regulation; clone cells; cyclic AMP; disease /disorder model; electrofocusing; epidermal growth factor; glucagon; hormone regulation /control mechanism; hormone related neoplasm /cancer; immunochemistry; kidney cell; monoclonal antibody; phorbols; phosphorylation; prostaglandin E; prostaglandin inhibitors; protein kinase; radiotracer; tissue /cell culture; transforming virus

The goal of our research effort is to understand the regulation of hormone responsiveness during cellular differentiation. Acquisition of hormone sensitivity often accompanies differentiation, therefore, by understanding its regulation, we will better understand the process of differentiation. In order to allow better control of experimental conditions, a model system using cultured cells was established. We found that in a dog kidney cell line, MDCK cells, glucagon responsiveness was selectively lost after transformation by Harvey murine sarcoma virus. This loss of hormone sensitivity can be restored to the transformed cells by culturing the cells in the presence of prostaglandin E2. The induction by PGE2 seems to be mediated by cyclic AMP. We also found that this induction process is inhibited by a serum factor, epidermal growth factor and a phorbol ester (TPA). Using these differentiation inhibitors, we are attempting to define the nature of this cyclic AMP-dependent process. It is apparent that the inhibitory effect of EGF resides downstream beyond the activation of cyclic AMP-dependent protein kinase. In the presence of PGE2 during induction, EGF receptors undergo a biphasic regulation. EGF binding increases initially and reaches a peak in 18 hr, then followed by a decrease to less than 20% of the maximal binding in 48 hr. The induction and the subsequent desensitization of EGF receptors suggest a cyclic AMP-dependent modulation of EGF effect. Using a semi-purified preparation of EGF receptors, we are currently studying their phosphorylation by both EGF- and cyclic AMP-dependent processes. In addition, we also found that the ras viral protein p21, production is decreased when cells are induced to differentiate. SInce a role in signal transduction has been suggested for p21, we are also examining the potential interaction between the viral protein and receptors for growth factors.

我们研究工作的目的是了解 细胞分化过程中的激素反应能力。 激素灵敏度的获取通常伴随 因此，通过理解法规的区分，我们将 更好地了解差异化过程。 为了允许 更好地控制实验条件，使用的模型系统使用 建立了培养的细胞。 我们发现在狗肾细胞中 线，MDCK细胞，胰高血糖素反应有选择性丢失 Harvey Murine肉瘤病毒转变后。 这个损失 激素灵敏度可以通过 在前列腺素E2存在下培养细胞。 这 PGE2诱导似乎是由环状AMP介导的。 我们也是 发现这种诱导过程受到血清因子的抑制 表皮生长因子和凤凰酯（TPA）。 使用这些 分化抑制剂，我们正在尝试定义性质 这一循环AMP依赖性过程。 显然 EGF的抑制作用位于下游 环状AMP依赖性蛋白激酶的激活。 在 诱导过程中PGE2的存在，EGF受体经历A 双相调节。 EGF结合最初增加并达到 18小时的峰值，然后减少到少于20％ 48小时内最大结合。 感应和随后的 EGF受体的脱敏表明环状AMP依赖性 EGF效应的调节。 使用半纯化的准备 EGF受体，我们目前正在研究其磷酸化 EGF和循环AMP依赖性过程。 另外，我们 还发现RAS病毒蛋白p21，生产降低 当诱导细胞分化时。 因为在信号中的作用 已建议使用P21的转导，我们也在检查 病毒蛋白与受体之间的潜在相互作用 对于生长因素。