Translational Control of Radiation-Induced Apoptosis

辐射诱导细胞凋亡的转化控制

• 批准号: 7059786
• 负责人: Benjamin Ping-Chi Chen
• 金额: $ 0.47万
• 依托单位: UT SOUTHWESTERN MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-12-01 至 2012-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7059786
• 关键词: DNA repair; bioassay; biotechnology; drug discovery /isolation; drug screening /evaluation; enzyme activity; enzyme inhibitors; high throughput technology; inhibitor /antagonist; method development; neoplasm /cancer radiation therapy; protein kinase; radiosensitizer; tissue /cell culture

DESCRIPTION (provided by applicant): Radiation treatment is one of the most important cancer-therapeutic approaches. Non-toxic radiosensitizers, used in conjunction with radiation therapy, would enhance the effectiveness of the radiotherapy and, at the same time, reduce the total radiation dose to prevent unwanted side effects. DNA double-strand breaks (DSBs) are the major DNA lesion induced by ionizing radiation (IR) and the dominant cause of radiation sensitivity. It is well established that lack of DSB repair can be lethal in mammalian cells. DNA-dependent protein kinase (DNA-PK) is the key component of the DNA nonhomologous end-joining (NHEJ) pathway that is the predominant pathway for DSB repair in mammalian cells. We have shown that inhibition of DNA-PK kinase activity and/or abrogation of radiation-induced autophosphorylation of DNA-PKcs (the catalytic subunit of DNA-PK) results in severe radiation sensitivity. As the autophosphorylation of DNA-PKcs is a requisite step for NHEJ mediated DSBs repair, molecules that inhibit autophosphorylation without affecting the protein levels of DNA-PK or its enzymatic activity could selectively radiosensitize cells without affecting other cellular processes; whereas molecules that inhibit the kinase activity of DNA-PK also commonly inhibit other PI-3K like protein kinases (ATM and ATR) and cause significant cellular toxicity. In this proposal, we plan to develop both lysate-based and cell-based high throughput screening (HTS) assay to identify chemicals or natural compounds that would either block the autophosphorylation of DNA-PKcs or inhibit the kinase activity of DNA-PKcs. With regard to the approaches,

描述（由申请人提供）：辐射治疗是最重要的癌症治疗方法之一。与放射疗法结合使用的无毒放射增敏剂将增强放射疗法的有效性，同时减少总辐射剂量以防止不必要的副作用。 DNA双链断裂（DSB）是电离辐射（IR）诱导的主要DNA病变，也是辐射敏感性的主要原因。众所周知，缺乏DSB修复可能在哺乳动物细胞中是致命的。 DNA依赖性蛋白激酶（DNA-PK）是DNA非同源末端连接（NHEJ）途径的关键成分，该途径是哺乳动物细胞中DSB修复的主要途径。我们已经表明，DNA-PK激酶活性的抑制和/或废除了辐射诱导的DNA-PKC（DNA-PK催化亚基）的自磷酸化导致严重的辐射敏感性。由于DNA-PKC的自磷酸化是NHEJ介导的DSBS修复的必要步骤，因此抑制自磷酸化的分子而不会影响DNA-PK或其酶促活性的蛋白质水平，可以选择性地将放射性放射性启动性化为细胞而不会影响其他细胞过程；而抑制DNA-PK激酶活性的分子也通常抑制其他PI-3K，例如蛋白激酶（ATM和ATR），并引起明显的细胞毒性。在此提案中，我们计划开发基于裂解物和基于细胞的高吞吐量筛选（HTS）测定法，以鉴定可以阻止DNA-PKC的自磷酸化的化学物质或天然化合物，或抑制DNA-PKC的激酶活性。关于方法，