DNA STRAND BREAKS AND THE GENETIC BASIS OF LYMPHOMAS

DNA 链断裂和淋巴瘤的遗传基础

• 批准号: 6173034
• 负责人: GILBERT CHU
• 金额: $ 22.11万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-08-12 至 2002-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6173034
• 关键词: DNA damage; DNA topoisomerases; ataxia telangiectasia; biopsy; cancer risk; enzyme activity; enzyme inhibitors; gene mutation; high performance liquid chromatography; human tissue; lymphoma; neoplasm /cancer genetics; neoplastic process; pathologic process; protein kinase; radiation resistance; tumor suppressor genes; western blottings

Mammalian cells respond to DNA double-strand breaks (DSBs) by activating pathways for cell cycle arrest and DNA repair. The signal for cell cycle arrest requires the ATM and p53 genes, which are mutated in at ataxia telangiectasia and Li-Fraumeni syndrome. DSB repair requires four genes: XRCC4, XRCC5 (Ku86), XRCC6 (Ku70), and XRCC7 (DNA-PKcs, the catalytic subunit of DNA-dependent protein kinase), the latter of which is mutated in the scid mouse. Ataxia telangiectasia and Li-Fraumeni patients and the scid mouse are highly susceptible to lymphoma. Thus, a small fraction of lymphomas must arise from germ line mutations in one of the DSB response genes. This proposal will test the hypothesis that a significant fraction arises from somatic mutations in these genes. The specific aims are to: 1.1. Test lymphoma tumors for biochemical abnormalities in pathways responding to DSBs. Lymphomas will be screened for biochemical abnormalities in the known DSB response genes. The assays are rapid and sensitive to mutations in these and other genes in the DSB response pathway. The assays will test DNA end-binding activity for Ku, assembly of DNA-PK on DNA ends and its enzymatic activity. Immunoblots will evaluate the Ku, DNA-PKcs, p53, and ATM proteins, which are often altered in stability of size by mutations. 1.2. Test lymphoma tumors for genetic abnormalities in pathways responding to DSBs. Lymphoma tumors will be tested for mutations in the DSB response genes. The hunt for mutations will be facilitated by new technology, which consists of denaturing high performance liquid chromatography and is capable of detecting mutations with greater than 98 percent sensitivity much more rapidly than conventional methods. 1.3. Correlate abnormalities in pathways responding to DSBs with clinical and other lab findings. Surprisingly, most diffuse lymphomas utilize the VH4.21 immunoglobulin gene. Since ATM mutations lead to aberrant V(D)J recombination, this proposal will test if they also lead to biased VH4.21 usage. Since many lymphomas do not have p53 mutations, this proposal will test whether the remaining lymphomas have mutations in ATM, which acts in the same signaling pathway. Since DSB response genes confer resistance to key anticancer agents, this proposal will test whether mutations in these genes affect clinical outcome. The long term goal is to define the genetic changes that mediate malignant progression of lymphomas. Hopefully, molecular analysis of individual lymphomas will some day lead to the cure of more patients.

哺乳动物细胞对DNA双链断裂（DSB）的反应是激活 细胞周期停滞和DNA修复的途径。 手机信号 周期阻滞需要ATM和p53基因，这两个基因在细胞内发生突变， 共济失调毛细血管扩张症和Li-Fraumeni综合征。 DSB修复需要 四个基因：XRCC 4、XRCC 5（Ku 86）、XRCC 6（Ku 70）和XRCC 7（DNA-PKcs， DNA依赖性蛋白激酶的催化亚基），后者 在SCID小鼠中发生了突变。 毛细血管扩张性共济失调与Li-Fraumeni 患者和SCID小鼠对淋巴瘤高度易感。 因此，在本发明中， 一小部分淋巴瘤一定是由其中一种的种系突变引起的 DSB反应基因。 这一提议将检验以下假设： 很大一部分来自这些基因的体细胞突变。 具体目标是：检测淋巴瘤肿瘤的生化 DSB反应通路的异常 淋巴瘤将是 筛查已知DSB反应基因的生化异常。 该检测方法对这些和其他基因的突变快速且敏感 在DSB反应途径中。 该检测将测试DNA末端结合 Ku活性、DNA-PK在DNA末端的组装及其酶促活性 活动 免疫印迹将评估Ku、DNA-PKcs、p53和ATM 蛋白质，其通常通过突变改变大小的稳定性。 1.2.测试淋巴瘤肿瘤的遗传异常的途径 回应DSB。 将检测淋巴瘤肿瘤中的突变， DSB反应基因。 寻找突变将由新的 技术，其中包括变性高性能液体 该方法可以通过色谱法进行，并且能够检测具有大于 98%的灵敏度比传统方法快得多。 1.3. DSB反应通路的异常与 临床和其他实验室检查结果。 令人惊讶的是，大多数弥漫性淋巴瘤 利用VH4.21免疫球蛋白基因。 由于ATM突变导致 异常的V（D）J重组，这项提议将测试它们是否也导致 有偏见的VH4.21使用 由于许多淋巴瘤没有p53突变， 这项计划将测试剩下的淋巴瘤是否有突变， 在ATM中，其作用于相同的信号通路。 自DSB回应以来 基因赋予对关键抗癌药物的抗性，这项提议将 测试这些基因的突变是否会影响临床结果。 长期目标是确定介导的遗传变化 淋巴瘤的恶性进展。 希望分子分析 个别的淋巴瘤有一天会治愈更多的病人。