Interplay between Cdh1 and major regulatory pathways in human cancer

Cdh1 与人类癌症主要调控途径之间的相互作用

基本信息

批准号：
8479373
负责人：
Wenyi Wei
金额：
$ 32.91万
依托单位：
BETH ISRAEL DEACONESS MEDICAL CENTER
依托单位国家：
美国
项目类别：
财政年份：
2009
资助国家：
美国
起止时间：
2009-08-06 至 2014-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8479373
关键词：
Acute Affect Affinity Chromatography Antineoplastic Agents Biochemical Bypass Cell Cycle Cell Cycle Checkpoint Cell Cycle Progression Cell Cycle Regulation Complex Cyclin E DNA Damage DNA Repair Data Development E2F1 gene Event Fibroblasts Genetic Genetic Materials Genome Stability Genomic Instability Goals Growth Hela Cells Human Knowledge Malignant Neoplasms Mediating Methods Molecular Oncogene Proteins Oncogenes Oncogenic PTEN gene Pathway interactions Phosphorylation Phosphotransferases Protein p53 Proteins Proteolysis Reagent Recovery Regulation Regulatory Element Regulatory Pathway Reporting Research Role S Phase Signal Transduction Testing Tumor Suppression Tumor Suppressor Genes Tumor Suppressor Proteins Ubiquitin Work base cancer therapy daughter cell inhibitor/antagonist insight neoplastic cell novel overexpression premature prevent public health relevance senescence tumor ubiquitin-protein ligase

项目摘要

DESCRIPTION (provided by applicant): Defective cell cycle regulation leads to genomic instability and ultimately cancer development. The E3 ubiquitin ligase APC/Cdh1 is a major regulator of cell cycle progression and has been implicated in DNA damage repair and tumor suppression, although its exact roles remain unclear. In this proposal, we will explore the interaction of Cdh1 with multiple major tumor suppressor and oncogenic pathways frequently altered in human cancers to define the novel functions as well as regulatory mechanisms for Cdh1. We previously reported that Cdh1 targets the Skp2 oncoprotein for proteolysis; our preliminary data showed that the PI3K/Akt pathway protected Skp2 from Cdh1-mediated destruction. In Aim 1, we will utilize both genetic and biochemical approaches to reveal the underlying molecular mechanisms by which Akt1 controls Skp2 abundance and cellular localization. The proposed studies will provide a novel mechanism for Skp2 overexpression in human cancers. It will also advance our knowledge of how specific kinase signaling cascades influence proteolysis governed by the APC/Cdh1 complex, and provide the rationale for developing Akt1-specific inhibitors as potent anti-cancer drugs. In Aim 2, we will define the molecular mechanisms by which loss of Cdh1 activates the p53 and Rb pathways, and their contribution to Cdh1 loss-induced premature senescence. We found that by controlling Claspin destruction, Cdh1 regulates Chk1 activity and further influences the p53 pathway, implicating a role for Cdh1 in DNA damage repair. We also found that Cdh1 could affect Rb/E2F1 function. As a result, depletion of Cdh1 in primary human fibroblasts led to the onset of premature senescence by activating both the p53 and Rb pathways. Inactivation of other tumor suppressors, including PTEN and VHL, also induced premature senescence, which has been proposed as a built-in fail-safe mechanism against cancer development. Our proposed work in Aim 2 will provide the possible underlying molecular mechanism for the less frequently observed Cdh1 loss in tumor cells, which could further imply Cdh1 loss as a late event in tumor development. Lastly, our proposal explores how Cdh1 itself is regulated. Our preliminary data indicated that the Mdm2 oncoprotein controls the stability of Cdh1 in late G1/S phase. This finding extends our understanding of the interplay between the Cdh1 and p53/Mdm2 pathways, and provides further evidence that the functions of major cell cycle regulators are interwoven to achieve synergized effects. Our proposed work in Aim 3 will provide a novel regulatory mechanism for Cdh1 stability control, thus uncovering another layer of mechanism for the oncogenic function of Mdm2 and supporting the use of Mdm2 inhibitors for cancer treatment. Altogether, these studies will significantly expand our current knowledge of the important functions of Cdh1 outside its classic role in cell cycle control by providing insight into how Cdh1 integrates into the network of major tumor suppressor (p53 and Rb) and oncogene (Akt and Mdm2) pathways to not only govern cell cycle progression, but also maintain genomic stability and participate in tumor suppression.

描述（由申请人提供）：细胞周期调节缺陷导致基因组不稳定并最终导致癌症发展。 E3 泛素连接酶 APC/Cdh1 是细胞周期进程的主要调节因子，与 DNA 损伤修复和肿瘤抑制有关，但其确切作用尚不清楚。在本提案中，我们将探讨 Cdh1 与人类癌症中经常改变的多种主要肿瘤抑制因子和致癌途径的相互作用，以确定 Cdh1 的新功能和调控机制。我们之前报道过 Cdh1 以 Skp2 癌蛋白为目标进行蛋白水解；我们的初步数据表明 PI3K/Akt 通路保护 Skp2 免受 Cdh1 介导的破坏。在目标 1 中，我们将利用遗传和生化方法来揭示 Akt1 控制 Skp2 丰度和细胞定位的潜在分子机制。拟议的研究将为人类癌症中 Skp2 过度表达提供一种新机制。它还将增进我们对特定激酶信号级联如何影响 APC/Cdh1 复合物控制的蛋白水解作用的了解，并为开发 Akt1 特异性抑制剂作为有效的抗癌药物提供依据。在目标 2 中，我们将定义 Cdh1 缺失激活 p53 和 Rb 通路的分子机制，以及它们对 Cdh1 缺失诱导的过早衰老的贡献。我们发现，通过控制 Claspin 破坏，Cdh1 调节 Chk1 活性并进一步影响 p53 通路，暗示 Cdh1 在 DNA 损伤修复中的作用。我们还发现Cdh1可以影响Rb/E2F1功能。结果，原代人成纤维细胞中 Cdh1 的消耗通过激活 p53 和 Rb 途径导致过早衰老的发生。其他肿瘤抑制因子（包括 PTEN 和 VHL）的失活也会引起过早衰老，这已被认为是对抗癌症发展的内置故障安全机制。我们在目标 2 中提出的工作将为肿瘤细胞中较少观察到的 Cdh1 丢失提供可能的潜在分子机制，这可能进一步表明 Cdh1 丢失是肿瘤发展的晚期事件。最后，我们的提案探讨了 Cdh1 本身是如何受到监管的。我们的初步数据表明，Mdm2 癌蛋白控制着 G1/S 期晚期 Cdh1 的稳定性。这一发现扩展了我们对 Cdh1 和 p53/Mdm2 通路之间相互作用的理解，并提供了进一步的证据，证明主要细胞周期调节因子的功能相互交织以实现协同效应。我们在目标 3 中提出的工作将为 Cdh1 稳定性控制提供一种新的调控机制，从而揭示 Mdm2 致癌功能的另一层机制，并支持使用 Mdm2 抑制剂进行癌症治疗。总而言之，这些研究将深入了解 Cdh1 如何整合到主要肿瘤抑制基因（p53 和 Rb）和癌基因（Akt 和 Mdm2）网络中，从而显着扩展我们目前对 Cdh1 在细胞周期控制中的经典作用之外的重要功能的了解。这些途径不仅控制细胞周期进展，而且维持基因组稳定性并参与肿瘤抑制。