Mechanisms of DNA damage-induced, p53-dependent repression of the Cdc25C Phosphat

DNA 损伤诱导的、p53 依赖性的 Cdc25C 磷酸盐抑制机制

• 批准号: 7914522
• 负责人: Luis A. Carvajal
• 金额: $ 3.34万
• 依托单位: ICAHN SCHOOL OF MEDICINE AT MOUNT SINAI
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-11-16 至 2012-06-19
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7914522
• 关键词: Address; Binding; Boxing; Cancer Patient; Cell Cycle Checkpoint; Cell Cycle Progression; Cell Death; Cells; DNA; DNA Binding; DNA Damage; DNA Methyltransferase; DNA Modification Methylases; Dependence; Elements; G2/M Transition; Genes; Histones; Human; Indium; Lead; Malignant Neoplasms; Mammalian Cell; Mediating; Methods; Molecular; Molecular Analysis; Molecular Target; Mutate; Phosphoric Monoester Hydrolases; Play; Protein Family; Protein p53; Repression; Response Elements; Role; TP53 gene; base; cancer cell; gene repression; novel therapeutic intervention; overexpression; promoter; public health relevance; response; therapeutic target; tool; tumorigenesis

DESCRIPTION (provided by applicant): The tumor suppressor p53 is the most commonly mutated gene found in human cancers [3]. It plays a vital role in guarding mammalian cells against tumorigenesis [22,23]. The Cdc25C phosphatase plays an important role in cell cycle progression at the G2/M transition [7-10]. Its activity is inhibited in response to DNA damage thereby contributing to the G2 checkpoint response [7-10]. Cdc25C is a target for transcriptional repression by p53. Overexpression of Cdc25C sensitizes cancer cells to DNA damage induced cell death [11, 12]. Interestingly, normal untransformed cells are not sensitized to this treatment [12]. Therefore, Cdc25C repression inhibition could lead to a novel therapeutic approach in combination with DNA damage. In order to address this possibility, a clear molecular basis for p53-dependent repression of Cdc25C must be described. As of yet, three distinct mechanisms of repression have been proposed, one involving direct binding to DNA by p53 and two indirect involving different elements. Each of which may provide molecular targets for inhibition. The present study aims to dissect the molecular basis for p53-dependent repression of Cdc25C and to explore its relevance as a tool that can be exploited in order to enhance chemotherapeutic responses in cancer patients. Hypothesis: It is hypothesized that the p53 response element is required in order for p53 to bind to the Cdc25C promoter and for the recruitment of co-repressors. Additional factors, such as p21, may be required for this repression. Furthermore, inhibition of this mechanism in cancer cells can abrogate DNA damage-induced Cdc25C repression, which results in heightened sensitivity to DNA damage-induced cell death. Specific Aims: Aim 1: Analysis of the molecular basis for DNA damage-induced p53-dependent repression of Cdc25C. A) Characterize the role of Histone Deacetylases (HDACs) and DNA methyltransferases (DNMTs) in Cdc25C repression. B) Study the role of CCAAT box binding factor, NF-Y in p53-dependent repression of Cdc25C. Aim 2: Functional analysis of different elements in the Cdc25C promoter. A) Characterize relevant elements in the Cdc25C promoter in order to identify potential therapeutic targets. B) Explore methods to use Cdc25C repression inhibition as a novel therapeutic approach. Aim 3: Study of the role of p21 in the p53-induced repression of Cdc25C. A) Investigate the p21 dependence of p53 and co-repressor recruitment to the Cdc25C promoter. B) Study the role of Rb family proteins in Cdc25C mediated repression in response to DNA damage. PUBLIC HEALTH RELEVANCE: The present study aims to dissect the molecular basis for p53-dependent repression of Cdc25C and to explore its relevance as a tool that can be exploited in order to enhance chemotherapeutic responses in cancer patients.

描述(申请人提供)：肿瘤抑制基因p53是人类癌症中发现的最常见的突变基因[3]。它在保护哺乳动物细胞不发生肿瘤方面起着至关重要的作用[22，23]。在G2/M转变过程中，CDC25C磷酸酶在细胞周期进程中起着重要作用[7-10]。它的活性在DNA损伤时被抑制，从而导致G2检查点反应[7-10]。CDC25C是P53转录抑制的靶点。CDC25C的过表达使癌细胞对DNA损伤导致的细胞死亡敏感[11，12]。有趣的是，正常的未转化细胞不会对这种治疗敏感[12]。因此，抑制CDC25C的抑制可能会导致一种结合DNA损伤的治疗新途径。为了解决这种可能性，必须描述依赖于P53的CDC25C抑制的明确分子基础。到目前为止，已经提出了三种不同的抑制机制，一种涉及P53直接与DNA结合，另两种间接涉及不同的元素。其中每一个都可能提供抑制的分子靶点。本研究旨在剖析P53依赖的CDC25C抑制的分子基础，并探讨其作为一种可用于增强癌症患者化疗反应的工具的相关性。假设：假设P53反应元件是P53与CDC25C启动子结合和共抑制因子招募所必需的。这种抑制可能需要其他因素，如p21。此外，在癌细胞中抑制这一机制可以取消DNA损伤诱导的CDC25C抑制，从而提高对DNA损伤诱导的细胞死亡的敏感性。具体目的：目的1：分析DNA损伤诱导的P53依赖性抑制CDC25C的分子基础。A)确定组蛋白脱乙酰酶(HDACs)和DNA甲基转移酶(DNMTs)在CDC25C抑制中的作用。B)研究CCAAT盒结合因子、核因子-Y在P53依赖的CDC25C抑制中的作用。目的2：CDC25C启动子中不同元件的功能分析。A)鉴定CDC25C启动子中的相关元件，以确定潜在的治疗靶点。B)探索使用CDC25C抑制作为一种新的治疗方法的方法。目的：研究p21在P53诱导的CDc25C抑制中的作用。A)研究P53对p21的依赖和共抑制物对CDC25C启动子的募集。B)研究Rb家族蛋白在CDC25C介导的抑制DNA损伤反应中的作用。 公共卫生相关性：本研究旨在剖析P53依赖的CDC25C抑制的分子基础，并探索其相关性，作为一种可以利用的工具，以增强癌症患者的化疗反应。