Altered Nuclear Protein Interactions and Radiosensitizat

热疗是已知的最有效的放射增敏剂之一。因此，项目1的目标是描述短时间中等热疗的放射致敏机制，以及通过增加热剂量增加放射致敏的机制，以便确定热诱导放射致敏增强剂的细胞靶点。众所周知，高温增强了蛋白质与核成分的结合，导致整个细胞核中蛋白质相互作用的改变。越来越多的证据表明，其中一些变化会导致放射致敏。然而，导致放射致敏的核蛋白相互作用的确切变化尚不清楚。因此，提出的工作的目的是描述核蛋白关联的变化由短时间，中等高温引起的辐射敏感性增加。第一步将是确定热诱导的dna修复蛋白Mrel 1从细胞核到细胞质的易位和/或其与功能伙伴的分离是否会引起短时间、中等高温的放射致敏（Specific Aim 1）。其次，我们将通过增加热剂量来确定核蛋白关联的哪些变化有助于增加放射致敏。该假设的第二部分是，热诱导的蛋白质与dna -核基质附着区域结合的增加有助于在热剂量高于放射致敏所需的最低剂量时（例如，急性热疗）增加放射敏感性。如果蛋白质构象的改变是导致热诱导放射致敏的蛋白质关联变化的原因，那么从这些影响中恢复可能需要蛋白质与分子伴侣（如hsp70）之间的关联，这将在Specific Aim 3中进行测试。通过确定中度热疗加HIR增强剂是否至少产生一些急性热疗的放射致敏效应，将在Specific Aim 4中验证放射致敏效应谱增加有助于增强放射致敏的假设。

Hyperthermia is one of the most effective radiosensitizers known. Therefore, the goal of Project 1 is to delineate the mechanisms of radiosensitization by short-duration moderate hyperthermia and the mechanism(s) by which radiosensitization is increased via increasing thermal dose, so that the cellular targets for enhancers of heat-induced radiosensitization will be defined. It is known that hyperthermia enhances protein binding to nuclear components, leading to altered protein-protein interactions throughout the nucleus. Accumulating evidence suggests that some of these changes cause radiosensitization. However, the exact changes in nuclear protein interactions that contribute to radiosensitization remain unknown. Thus, the objectives of the proposed work are to delineate the changes in nuclear protein associations induced by short duration, moderate hyperthermia that lead to increased radiosensitivity. The first step will be to determine if the heat-induced translocation of the DNA-repair protein, Mrel 1, from the nucleus to the cytoplasm and/or its dissociation from its functional partners causes radiosensitization by short-duration, moderate hyperthermia (Specific Aim 1). Second, we will determine which changes in nuclear protein association contribute to increasing radiosensitization by increasing thermal dose. The second part of the hypothesis is that the heat-induced increase in the binding of proteins to DNA-nuclear matrix attachment regions contribute to increased radiosensitivity at thermal doses above the minimum required for radiosensitization (e.g., acute hyperthermia). If altered protein conformations are responsible for changes in protein associations that lead to heat-induced radiosensitization, it is likely that recovery from these effects would require an association between the protein and a molecular chaperone(s) e.g., hsp70, which will be tested in Specific Aim 3. The hypothesis that an increasing spectrum of radiosensitizing effects contribute to enhanced radiosensitization will be tested in Specific Aim 4, by determining if moderate hyperthermia, plus an enhancer of HIR produces at least some of the radiosensitizing effects of acute hyperthermia.