RADIOSENSITIVITY PROGNOSIS BASED ON DNA REPAIR ASSAY

基于 DNA 修复测定的放射敏感性预测

• 批准号: 3177731
• 负责人: CHRISTOPHER S. LANGE
• 金额: $ 10.55万
• 依托单位: SUNY DOWNSTATE MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 1984
• 资助国家: 美国
• 起止时间: 1984-12-01 至 1989-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3177731
• 关键词: DNA; DNA repair; biological models; prognosis; radiation genetics; radiation sensitivity; tissue /cell culture

This program will use the recently developed method of viscoelastometry (VE) to measure the size, conformation, and concentration (number) of mammalian chromosomal DNA molecules. By comparing changes in molecular size (Gamma), conformation (relative Tau and Gamma), and size concentration (ri) distribution, as functions of radiation dose and postirradiation treatment and/or repair, the rates of induction and repair of double-stand breaks (DSBs) will be determined. Cellular loss of reproductive integrity will be correlated with unrepaired DSBs per cell in order to determine if the unrepaired DSB is the major lethal lesion. Should such a correlation prove significant, the basis for a DNA based assay for cellular radiosensitivity will have been established. Since VE can detect the effects of clinically (and biologically) relevant doses (0.50 - 20 Gy), the above relationship will then provide a useful clinical assay. This assay will be tested in a competing renewal of this proposal. In addition, several biologically important points will be established by the data we propose to collect. The first of these is a determination as to whether mammalian chromosomal DNA consists of linear or circular molecules. At present nok data exist which directly demonstrate the DNA conformation. The data we propose to collect will demonstrate either the linear or the circular nature of relaxed chromosomal DNA in mammalian cells. This has far reaching consequences for our understanding of chromosome structure. The second point will be the determination of a general method for the determination of the D37, DSB and molecular conformation by the use of VE. The third point will be a test of the hypothesis that the shapes of the cell survival curves can be explained solely in terms of potentially lethal lesions (PLL) and their repair. We will examine the effects of postirradiation repair time followed by hypertonicity treatment to see if cell survival curves consistent with this interpretation are obtained. This has been done in one cell line but it is not clear if this is a general finding. The fourth point will be the determination of the number of unrepaired DSBs after each of the treatment used to assess PLL, and a test as to whether the PLL can be correlated with the DSB.

该程序将使用最近开发的粘弹性测量方法 (VE) 测量尺寸、构象和浓度（数量） 哺乳动物染色体DNA分子。 通过比较分子变化 大小（Gamma）、构象（相对 Tau 和 Gamma）和大小浓度 (ri) 分布，作为辐射剂量和辐射后的函数 治疗和/或修复，双支架的诱导和修复率 中断（DSB）将被确定。 细胞生殖完整性丧失 将与每个细胞未修复的 DSB 相关联，以确定是否 未修复的 DSB 是主要的致命损伤。 应该有这样的相关性 证明具有重要意义，是基于 DNA 的细胞检测的基础 放射敏感性将被确定。 由于 VE 可以检测到 临床（和生物学）相关剂量（0.50 - 20 Gy）的影响， 上述关系将提供有用的临床测定。 本次检测 将在该提案的竞争性更新中进行测试。 此外，还将确定几个生物学上的重要观点： 我们建议收集的数据。 其中第一个是确定 哺乳动物染色体DNA是否由线性或环状组成 分子。 目前存在直接证明DNA的nok数据 构象。 我们建议收集的数据将证明 哺乳动物松弛染色体DNA的线性或环状性质 细胞。 这对我们的理解产生了深远的影响 染色体结构。 第二点是确定 D37、DSB 和分子质量测定通用方法 通过使用VE进行构象。 第三点将是一个测试 假设细胞存活曲线的形状可以解释 仅就潜在致命损伤（PLL）及其修复而言。 我们 将检查辐照后修复时间的影响，然后 高渗治疗，看看细胞存活曲线是否与此一致 获得解释。 这已在一种细胞系中完成，但它是 不清楚这是否是一个普遍的发现。 第四点将是 确定每次处理后未修复的 DSB 数量 用于评估 PLL，并测试 PLL 是否可以与 DSB。