CELL CYLCE REGULATION OF EPITHELIAL CELL GROWTH

上皮细胞生长的细胞周期调节

• 批准号: 3460374
• 负责人: Philip H Howe
• 金额: $ 8.88万
• 依托单位: CLEVELAND CLINIC FOUNDATION
• 依托单位国家: 美国
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-02-01 至 1997-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3460374
• 关键词: SDS polyacrylamide gel electrophoresis; affinity chromatography; aminoacid analyzer; autoradiography; carcinogenesis; cell growth regulation; enzyme activity; enzyme biosynthesis; epithelium; growth inhibitors; histones; immunoprecipitation; laboratory rabbit; northern blottings; oncogenes; posttranslational modifications; protein kinase; radiotracer; synchronous cell division; transforming growth factors

Controlled celullar proliferation requires the integration of both stimulatory and inhibitory signals. Transforming growth factor beta-1 (TGF-beta 1) is unique in that it is capable of conveying either a growth stimulatory or growth inhibitory signal. It is of interest to consider that the loss of a growth inhibitory response may be just as significant in the development of cancer as the acquisition of a growth stimulatory response. Thus, identification of the regulatory substrates for normal epithelial cell growth inhibition by TGF-beta-1 is of fundamental importance. Our recent data demonstrate that the inhibition of epithelial cell proliferation by TGF-beat-1 occurs late in the G1 phase of the cell cycle, approximately 1-2 hours from the onset of DNA synthesis. Associated with this inhibitory effect on cellular proliferation is a TGF-beta-1- induced decrease in the phosphorylation and histone H1 kinase activity of p34cdc2. The protein kinase p34c6c2, a ubiquitous inducer of mitosis in eukaryotic cells, has also been implicated in the regulation of the G1/S transition. During progression through the cell cycle p34cdc2 undergoes a series of posttranslational modifications, subunit rearrangements, and oscillations in its synthetic rate, which are thought to be associated with its activation. Despite rapid progress in the characterization of p34cdc2 at the induction of mitosis in mammalian cells, little is known about the mechanisms regulating its activation in G1 and S phase. The experiments proposed in this application are designed to test the hypothesis that the inhibitory action of TGF-beta 1 on epithelial cell proliferation is mediated through its effects on p34cdc2 activity at the Gl/S transition. Specifically, the effects of TGF-beta-1 on the epithelial cycle-dependent post-translational regulation (i.e. phosphorylation) and biosynthetic rate of p34cdc2 will be investigated. These objectives will be achieved by the following specific aims: 1) Determine the effect of TGF-beta-1 on the phosphoamino acid profile and kinase activity of p34cdc2 throughout the cell cycle of epithelial cells. 2) Determine the mechanism by which TGF-beta-1 decreases p34cdc2 phosphorylation at the G1/S phase border. 3) Determine the effect of TGF-beta-1 on the cell cycle-dependent rate of synthesis of p34cdc2. 4) Determine the effect of TGF-beta-1 on p34cdc2 regulation in lung epithehal cells transfected with activated oncogenes. These studies should increase our understanding of normal growth control and provide mechanistic information as to potential regulatory targets for carcinoma development.

受控的细胞增殖需要两者的整合 刺激和抑制信号。 转化生长因子β-1 (TGF-beta 1) 的独特之处在于它能够传递生长因子 刺激或生长抑制信号。 值得考虑的是 生长抑制反应的丧失可能同样重要 癌症的发展是由于获得了生长刺激剂 回复。 因此，正常的调节底物的鉴定 TGF-β-1 抑制上皮细胞生长具有重要意义 重要性。 我们最近的数据表明，上皮细胞的抑制 TGF-beat-1 导致的细胞增殖发生在细胞 G1 期晚期 周期，从DNA合成开始大约1-2小时。 联系 具有这种对细胞增殖的抑制作用的是TGF-β-1- 诱导磷酸化和组蛋白 H1 激酶活性降低 p34cdc2。 蛋白激酶 p34c6c2，一种普遍存在的有丝分裂诱导剂 真核细胞，也参与 G1/S 的调节 过渡。 在细胞周期的进展过程中，p34cdc2 经历了 一系列翻译后修饰、亚基重排，以及 其合成速率的振荡被认为与 它的激活。 尽管 p34cdc2 的表征取得了快速进展 关于哺乳动物细胞有丝分裂的诱导，人们知之甚少 调节其 G1 和 S 期激活的机制。 实验 本申请中提出的旨在测试以下假设： TGF-β1对上皮细胞增殖的抑制作用是 通过其对 Gl/S 转换时 p34cdc2 活性的影响来介导。 具体而言，TGF-β-1 对上皮细胞周期依赖性的影响 翻译后调节（即磷酸化）和生物合成速率 p34cdc2的将被调查。 这些目标将通过 以下具体目标： 1) 确定 TGF-β-1 对磷酸氨基酸谱的影响和 p34cdc2在整个上皮细胞周期中的激酶活性 细胞。 2) 确定TGF-beta-1降低p34cdc2的机制 G1/S 相边界的磷酸化。 3) 确定TGF-β-1对细胞周期依赖性速率的影响 p34cdc2 的合成。 4) 确定TGF-β-1对肺中p34cdc2调节的影响 用激活的癌基因转染的上皮细胞。 这些研究应该增加我们对正常生长控制的理解 并提供有关潜在监管目标的机制信息 癌的发展。