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

• 批准号: 7906975
• 负责人: Wenyi Wei
• 金额: $ 34.43万
• 依托单位: BETH ISRAEL DEACONESS MEDICAL CENTER
• 依托单位国家: 美国
• 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/7906975
• 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; Figs - dietary; G1 Phase; 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; Phase; Phosphorylation; Phosphotransferases; Protein p53; Proteins; Proteolysis; Reagent; Recovery; Regulation; Regulatory Element; Regulatory Pathway; Reporting; Research; Role; Signal Transduction; TP53 gene; 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

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. PUBLIC HEALTH RELEVANCE: APC/Cdh1, whose function has been implicated in DNA damage repair and tumor suppression, is a critical regulator that governs cell cycle progression. However, the underlying molecular mechanisms are unknown. We plan to study the interplay between Cdh1 and major tumor suppressors (p53 and Rb) and oncogenic (Akt and Mdm2) pathways, thus uncovering the regulatory functions of Cdh1 in cell cycle checkpoint, DNA damage repair and tumor suppression. These studies will provide valuable insight into how Cdh1 integrates into the network of tumor suppressor/oncogene pathways to maintain genomic stability and suppress tumor development, and will also provide the rationale for developing specific Akt1 and Mdm2 inhibitors as potent anti-cancer reagents.

描述（由申请人提供）：有缺陷的细胞周期调节导致基因组不稳定性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剂，尽管其确切的作用仍然不清楚，但仍与DNA损伤修复和抑制肿瘤有关。在此提案中，我们将探索CDH1与人类癌症经常改变的多个主要肿瘤抑制和致癌途径的相互作用，以定义新功能以及CDH1的调节机制。我们先前报道说，CDH1靶向SKP2癌蛋白用于蛋白水解。我们的初步数据表明，PI3K/AKT途径保护了SKP2免受CDH1介导的破坏。在AIM 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过表达提供新的机制。它还将促进我们对特定激酶信号级联反应如何影响由APC/CDH1复合物控制的蛋白水解的知识，并为开发Akt1特异性抑制剂作为有效的抗癌药物提供了理由。在AIM 2中，我们将定义CDH1损失激活p53和RB途径的分子机制，以及它们对CDH1损失诱导的过早衰老的贡献。我们发现，通过控制悬垂破坏，CDH1调节CHK1活性并进一步影响p53途径，这暗示了CDH1在DNA损伤修复中的作用。我们还发现CDH1可能影响RB/E2F1功能。结果，CDH1在原代人成纤维细胞中的耗竭导致了通过激活p53和RB途径的过早衰老的发作。包括PTEN和VHL在内的其他肿瘤抑制剂的失活也诱发了早期衰老，该衰老已被认为是针对癌症发展的内置故障安全机制。我们在AIM 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，这可能进一步暗示CDH1丢失是肿瘤发育中的后期事件。最后，我们的建议探讨了CDH1本身的调节方式。我们的初步数据表明，MDM2癌蛋白控制G1/S晚期CDH1的稳定性。这一发现扩展了我们对CDH1和p53/MDM2途径之间相互作用的理解，并提供了进一步的证据表明，主要细胞周期调节剂的功能已交织以实现协同作用。我们在AIM 3中提出的工作将为CDH1稳定性控制提供一种新型的调节机制，从而揭示了MDM2致癌功能的另一种机制，并支持使用MDM2抑制剂用于癌症治疗。总的来说，这些研究将通过提供有关CDH1如何整合到主要肿瘤抑制剂（p53和RB）和Oncogene（AKT和MDM2）网络中，从而大大扩展我们当前对CDH1重要功能的知识超出其在细胞周期控制中的经典作用。不仅控制细胞周期进展的途径，而且还保持基因组稳定性并参与抑制肿瘤。公共卫生相关性：APC/CDH1的功能已与DNA损伤修复和抑制肿瘤有关，是控制细胞周期进展的关键调节剂。但是，基本的分子机制尚不清楚。我们计划研究CDH1与主要肿瘤抑制剂（P53和RB）以及致癌（AKT和MDM2）途径之间的相互作用，从而发现CDH1在细胞周期检查点，DNA损伤修复和肿瘤抑制中的调节功能。这些研究将为CDH1如何整合到肿瘤抑制剂/致癌基因途径网络中，以保持基因组稳定性和抑制肿瘤的发展，并为开发特定的AKT1和MDM2抑制剂作为有效的抗癌试剂提供基本原理。