MECHANISMS OF RDIATION RESPONSE AND ADP RIBOSE METABOLISM

辐射响应和 ADP 核糖代谢机制

• 批准号: 6217504
• 负责人: VICENTE NOTARIO
• 金额: $ 19.95万
• 依托单位: GEORGETOWN UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-08-05 至 2000-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6217504
• 关键词: ADP ribosylation; DNA binding protein; DNA damage; DNA footprinting; DNA repair; adenine phosphoribosyltransferase; apoptosis; enzyme activity; flow cytometry; gel mobility shift assay; genetic transcription; ionizing radiation; molecular cloning; molecular pathology; neoplasm /cancer radiation therapy; neoplastic cell culture for noncancer research; polymerase chain reaction; protein metabolism; proteolysis; radiation sensitivity; transfection /expression vector; western blottings

The overall objective of this proposal is to investigate the role of poly(ADP-ribose) polymerase (PARP) in the cellular response to ionizing radiation injury. Evidence accumulated from experiments performed by us and others indicates that, although PARP appears to be an element in the G2 checkpoint in mammalian cells, it is not an essential gene for DNA replication or the nucleotide excision pathway for DNA repair. These findings support that the cellular radiation response rely on effective poly(ADP-ribose) metabolism. We hypothesize that the level and mode of action of activated PARP is critical for recovery from ionizing radiation damage to DNA, and that perturbations in the normal regulatory systems for PARP levels and activity by excessive DNA damage result in the potentiation of the apoptosis pathway in the cellular response. Using Ewing's sarcoma (EWS) cells as the primary experimental model system for radiosensitivity and high PARP levels, we propose an experimental approach designed to: 1) study the transcriptional regulation of PARP and determine if it is altered by radiation exposure, 2) identify proteolytic systems involved in the turnover of the PARP gene product, and 3) establish the participation and role of the PARP-turnover proteases in the response to radiation-induced DNA damage and apoptosis. Data from these experiments will identify molecular events associated with the cellular response to ionizing radiation. An important limiting factor in tumor treatment by radiation therapy is the intrinsic radiosensitivity of tumor cells. Understanding the mechanisms of radiation response, particularly those potentiating tumor cell apoptosis, will allow the development of strategies for improving the clinical therapeutic ratio.

该提议的总体目的是调查 细胞对电离反应中的聚（ADP-核糖）聚合酶（PARP） 辐射损伤。从我们执行的实验中积累的证据 其他人则表明，尽管PARP似乎是 哺乳动物细胞中的G2检查点，它不是DNA的必要基因 复制或用于DNA修复的核苷酸切除途径。这些 发现支持细胞辐射反应依赖有效的发现 聚（ADP-核糖）代谢。我们假设 激活PARP的作用对于从电离辐射中恢复至关重要 DNA的损害，以及正常调节系统中的扰动 PARP水平和通过过度DNA损伤的活动导致 细胞反应中凋亡途径的增强。 使用Ewing的肉瘤（EWS）细胞作为主要实验模型系统 对于放射敏性和高PARP水平，我们提出了一个实验 设计的方法：1）研究PARP的转录调节和 确定是否通过辐射暴露对其进行改变，2）识别蛋白水解 参与PARP基因产物营业额的系统，3） 建立PARP转变蛋白酶的参与和作用 对辐射引起的DNA损伤和凋亡的反应。 这些实验的数据将确定与 细胞对电离辐射的反应。一个重要的限制因素 在肿瘤治疗中，通过放射治疗是固有的放射线敏感性 肿瘤细胞。了解辐射反应的机制， 特别是那些增强肿瘤细胞凋亡的人，将允许 制定改善临床治疗比率的策略。