GENOMIC INSTABILITY IN TUMORS OF TRANSGENIC MICE

转基因小鼠肿瘤的基因组不稳定性

• 批准号: 2749710
• 负责人: RICHARD A WINEGAR
• 金额: $ 28.63万
• 依托单位: SRI INTERNATIONAL
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-08-05 至 2000-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2749710
• 关键词: 3,4 methylenedioxyamphetamine; acetylaminofluorene; animal genetic material tag; chemical carcinogen; chemical carcinogenesis; diethylnitrosamine; environment related neoplasm /cancer; gene mutation; genetically modified animals; laboratory mouse; liver neoplasms; mutagens; neoplasm /cancer classification /staging; neoplasm /cancer genetics; nucleic acid sequence; phenobarbital; polymerase chain reaction; reporter genes; tumor suppressor genes

Carcinogenesis is a multistage process that progresses via a series of mutations in specific oncogenes and tumor suppressor genes. Evidence suggests that spontaneous mutation rates alone cannot account for the level of mutations observed in most tumors. A hypothesis for the elevated mutation rates in tumors is that tumor progression may be aided by the acquisition of a "mutator" phenotype that produces genomic instability. Gene amplification, microsatellite alterations, and chromosome aberrations have been observed in many tumor types. However, there has been little characterization of instability in the form of gene mutations, especially in vivo. Transgenic mice with a lacI target gene allow rapid quantitation and sequencing of mutations in nearly any tissue or tumor. This system is useful for studying genomic instability because, unlike oncogenes and tumor suppressor genes, mutations in the nontranscribed lacI gene confer no selective growth advantage or disadvantage. Preliminary studies show that mouse liver tumors have an elevated lacI mutation frequency consistent with the hypothesis of cancer-related genomic instability. The objective of this proposed research is to use transgenic lacI and p53 +/- mice to characterize genomic instability in tumors in response to genotoxic and nongenotoxic environmental carcinogens. The specific aims will be to 1) determine the level of genomic instability in lacI transgenic mouse liver tumors that are spontaneous or induced by treatment with genotoxic and nongenotoxic agents, alone or in combination; 2) characterize the nature of genomic instability in tumors by characterizing mutational spectra at the lacI gene; 3) correlate genomic instability at the lacI gene with tumor stage, microsatellite instability, activation of Ha-ras, alterations in p53, and cell proliferation; 4) determine the role of p53 in cancer-related genomic instability using lacI/p53+/- transgenic mice; and 5) determine whether genomic instability and other alterations observed in liver tumors are present in tumors at other sites. A large database of DNA sequence and molecular changes associated with carcinogenesis will be develops The information obtained should improve the understanding of the role of genomic instability in cancer. Such information may lead to novel therapeutic targets and diagnostic tools.

致癌过程是一个多阶段过程，它通过一系列 特定的癌基因和肿瘤抑制基因的突变。 证据 表明仅自发突变率不能说明 在大多数肿瘤中观察到的突变水平。高架的假设 肿瘤中的突变率是肿瘤进展可以通过 获得产生基因组不稳定性的“突变器”表型。 基因扩增，微卫星改变和染色体畸变 在许多肿瘤类型中都观察到。但是，几乎没有 以基因突变的形式表征不稳定性 体内。具有LACI靶基因的转基因小鼠可以快速定量 以及几乎所有组织或肿瘤中突变的测序。这个系统是 对于研究基因组不稳定性有用，因为与癌基因和 肿瘤抑制基因，非转录LACI基因赋予的突变 没有选择性的增长优势或劣势。初步研究表明 小鼠肝肿瘤的LACI突变频率升高 与癌症相关基因组不稳定性的假设一致。这 这项拟议的研究的目的是使用转基因LACI和p53 +/- 小鼠表征肿瘤中基因组不稳定性的反应 遗传毒性和非核环境致癌物。具体目标 将是1）确定LACI中基因组不稳定性水平 由治疗自发或诱导的转基因小鼠肝肿瘤 单独或组合使用遗传毒性和非基因毒剂； 2） 通过表征肿瘤中基因组不稳定性的性质 LACI基因的突变光谱； 3）将基因组不稳定性在 具有肿瘤阶段的LACI基因，微卫星不稳定性，激活 HA-RAS，p53的改变和细胞增殖； 4）确定角色 使用LACI/p53 +/-转基因的癌症相关基因组不稳定性中的p53 小鼠； 5）确定基因组不稳定性和其他改变是否 在肝肿瘤中观察到的其他部位的肿瘤中存在。一个大 与DNA序列和分子变化的数据库 癌变将开发，获得的信息应改善 理解基因组不稳定性在癌症中的作用。这样的 信息可能导致新颖的治疗靶标和诊断工具。