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.

癌变是一个多阶段的过程，通过一系列的过程进行 特定癌基因和抑癌基因的突变。 证据 表明自发突变率本身并不能解释 在大多数肿瘤中观察到的突变水平。升高的假设 肿瘤的突变率是肿瘤进展可能有助于 获得产生基因组不稳定的“突变”表型。 基因扩增、微卫星改变和染色体畸变 已在多种肿瘤类型中观察到。然而，已经很少有 基因突变形式的不稳定性特征，特别是 体内。带有 lacI 靶基因的转基因小鼠可实现快速定量 以及对几乎任何组织或肿瘤中的突变进行测序。这个系统是 对于研究基因组不稳定性很有用，因为与癌基因不同 肿瘤抑制基因，非转录 lacI 基因的突变赋予 没有选择性增长的优势或劣势。初步研究表明 小鼠肝脏肿瘤的 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 这项研究的目标是使用转基因 lacI 和 p53 +/- 小鼠表征肿瘤中基因组不稳定性的响应 遗传毒性和非遗传毒性环境致癌物。具体目标 将是 1) 确定 lacI 中基因组不稳定性的水平 自发性或治疗诱导的转基因小鼠肝脏肿瘤 与基因毒性剂和非基因毒性剂单独或组合使用； 2） 通过表征来表征肿瘤中基因组不稳定性的本质 lacI 基因的突变谱； 3) 关联基因组不稳定性 lacI 基因与肿瘤分期、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+/- 转基因研究 p53 在癌症相关基因组不稳定性中的作用 老鼠； 5) 确定基因组是否不稳定和其他改变 在肝脏肿瘤中观察到的现象也存在于其他部位的肿瘤中。一个大 DNA 序列和相关分子变化的数据库 致癌作用将会发展 所获得的信息应该有所改善 了解基因组不稳定性在癌症中的作用。这样的 信息可能会带来新的治疗靶点和诊断工具。