Cancer Susceptibility and MSI Analyses of Mlh3 Null Mice

Mlh3 无效小鼠的癌症易感性和 MSI 分析

• 批准号: 7115020
• 负责人: Steven M Lipkin
• 金额: $ 29.23万
• 依托单位: UNIVERSITY OF CALIFORNIA-IRVINE
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-09-01 至 2009-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7115020
• 关键词: DNA damage; DNA repair; SDS polyacrylamide gel electrophoresis; apoptosis; cancer risk; carcinogenesis; cell death; cell growth regulation; colorectal neoplasms; disease /disorder model; frameshift mutation; gastrointestinal epithelium; gene induction /repression; gene rearrangement; genetic susceptibility; genetically modified animals; high throughput technology; intestine neoplasm; laboratory mouse; molecular cloning; neoplasm /cancer genetics; polymerase chain reaction; preneoplastic state; terminal nick end labeling

DESCRIPTION (provided by applicant): Defective DNA mismatch repair (MMR) causes cancer. MMR mutations use multiple distinct mechanisms to cause cancer: (A) Defective repair of insertion/deletion frameshift mutations (commonly called Microsatellite Instability or MSI), (B) Defective repair of single-basepair DNA mismatches, and (C) Failure to initiate apoptosis in response to DNA damage. Previously, I cloned MLH3. Both inherited and sporadic MLH3 mutations cause CRC and perhaps other types of cancer as well. Gerrnline and sporadic MLH3 mutations are associated with both MSI v and MSI- CRCs. In mice, Mlh3 is essential for meiosis. New results from my lab demonstrate Mlh3 -/- and Mlh3-/-/Pms2-/- mice develop multiple types of cancer, including bowel cancer. However, studies to date have not addressed critical questions: What are the mechanisms of carcinogenesis in cells with MLH3 mutations? What are the mechanisms of carcinogenesis in cells with both MLH3 and PMS2 mutations? We therefore propose the following Aims: Specific Aim 1: To Identify the Mechanisms of Apc Inactivation in Mlh3 -/- and Mlh3-/- Pms2-/- Bowel Cancers. These mechanisms are important to determine because MLH3 and PMS2 mutations underlie both inherited and sporadic forms of CRC in patients. Specific Aim 2: To Analyze Mlh3 -/- Cells for Defects in DNA Damage Induced Apoptosis as a Potential Mechanism of Carcinogenesis. This aim tests the hypothesis that Mlh3 -/- cells do not correctly initiate apoptosis in response to DNA damage as a potential mechanism of carcinogenesis. Specific Aim 3: To Determine Insertion/Deletion MSI and Single-Basepair Mismatch Repair Phenotypes of Mlh3 -/-cells in vitro and in rive as potential mechanisms of carcinogenesis. The aim tests two hypotheses: (1) Mlh3 mutations cause MSI and (2) Mlh3 mutations disrupt single-basepair mismatch repair.

描述（由申请人提供）：DNA不匹配修复（MMR）导致癌症。 MMR突变使用多种不同的机制引起癌症：（a）修复插入/缺失移码突变（通常称为微卫星不稳定性或MSI），（b）单BASEPAIR DNA不匹配的修复有缺陷，以及（C）（C）未能因响应DNA损伤而无法启动凋亡。 以前，我克隆了MLH3。遗传和零星的MLH3突变也会引起CRC以及其他类型的癌症。 Gerrnline和零星MLH3突变与MSI V和MSI-CRC都相关。在小鼠中，MLH3对于减数分裂至关重要。我的实验室的新结果表明MLH3 - / - 和MLH3 - / - /PMS2 - / - 小鼠会形成多种类型的癌症，包括肠癌。但是，迄今为止的研究尚未解决关键问题：MLH3突变细胞中癌变的机制是什么？ MLH3和PMS2突变的细胞中癌变的机制是什么？因此，我们提出以下目标： 具体目标1：确定MLH3 - / - 和MLH3 - / - PMS2 - / - 肠癌中APC失活的机制。这些机制对于确定很重要，因为MLH3和PMS2突变是患者的遗传和零星形式的基础。 具体目的2：分析MLH3 - / - 细胞，以使DNA损伤的缺陷诱导凋亡作为癌变的潜在机制。该目标检验了以下假设：MLH3 - / - 细胞无法正确启动凋亡，以响应DNA损伤作为致癌作用的潜在机制。 特定目的3：确定MLH3 - / - 细胞在体外和Rive中的插入/缺失MSI和单键型不匹配修复表型，作为致癌作用的潜在机制。目的检验了两个假设：（1）MLH3突变导致MSI，（2）MLH3突变破坏了单键epair不匹配的修复。