Pharmacological Approaches Increasing Thermal Radiosensi

本项目将检验高温诱导细胞和/或核发生特定变化，使细胞对电离辐射敏感的假设。这一假说的一个推论是，引起与热相同变化的化学或物理因子也会导致细胞变得对辐射敏感。建立这一假说及其推论提供了本项目的基础：鉴定和开发诱导辐射增敏的药理学试剂 利用与热休克相同的分子途径，并可用于增强中度高温的放射增敏作用。 目的1：验证核内蛋白质聚集可增加辐射敏感性的假设。为了实现这一目标，我们将使用稳定转染有条件表达GFP融合蛋白的载体的细胞，该融合蛋白被工程化以在细胞核或细胞质中自发聚集。 目的2：确定提高热辐射增敏作用的药理学药物。消炎痛是我们的起始化合物。以前的工作已经确定，吲哚美辛可以作为一个辐射增敏剂和热辐射增敏增强剂。其他独立的工作表明，吲哚美辛降低了热诱导蛋白质聚集所需的温度，并降低了Hsf-1活化所需的温度，使得在本身不足以活化的温度下可以获得完全的热休克反应。 目的3）确定具有热辐射增敏作用的蒽酮类似物的结构特征。将合成吲哚美辛类似物并进行结构-功能分析，以使增强剂活性最大化并使毒性最小化。类似物设计将基于目标1和2中确定的分子决定簇。也就是说，我们将鉴定和设计具有优化结构特征的类似物，以引起蛋白质聚集、DNA传感器功能抑制和NADPH氧化酶活性激活。目的4：确定目的3中鉴定的吲哚美辛类似物是否增强体内热放射增敏作用。 将使用两种人异种移植肿瘤模型（NSY和HT-29）。将由体内程序核心进行试验。类似物选择的标准将基于目标3中进行的体外试验获得的结果。将在体内测试在增强子活性方面最有效、毒性最小并且表现出对环氧合酶-1和-2的最小抑制的类似物。

This project will test the hypothesis that hyperthermia induces specific cellular and/or nuclear changes that sensitize cells to ionizing radiation. A corollary of this hypothesis is that chemical or physical agents that induce the same changes as heat will also cause cells to become radiosensitive. Establishing this hypothesis and its corollary provide the basis of this project: the identification and development of pharmacological agents that induce radiation sensitization utilizing the same molecular pathways as heat shock and can be used to enhance the radiosensitizing effects of moderate hyperthermia. Aim 1: Test the hypothesis that radiation sensitivity can be increased by the aggregation of proteins in the nucleus. To accomplish this aim, we will use cells stably transfected with vectors that conditionally express GFPfusion proteins engineered to spontaneously aggregate in the nucleus or in the cytosol. Aim 2: Identify pharmacological agents that enhance hyperthermic radiosensitization. The NSAID indomethacin is our starting compound. Previous work has established that indomethacin can act a radiosensitizer and enhancer of thermal radiosensitization. Other, independent work, has shown that indomethacin lowers the temperature necessary for the heat induced protein aggregation and lowers the temperature necessary for Hsf-1 activation, such that a complete heat shock response can be attained at temperatures that are by themselves, insufficient for activation. Aim 3) Determine the structural features of inflole analogs that confer thermal radiosensitization. Indomethacin analogs will be synthesized and subjected to a structure-function analysis in order to maximize enhancer activity and minimize toxicity. Analog design will be based on the molecular determinates identified in Aims 1 and 2. That is, we will identify and design analogs with structural features optimized to cause protein aggregation, DNA sensor function inhibition and activation ofNADPH oxidase activity. Aim 4: Determine if the indomethacin analogs identified in Aim 3 enhance thermal radiosensitization in vivo. Two human xenograph tumor models (NSY and HT-29 will be used. Testing will be performed by the in vivo procedures core. The criteria for analog selection will be based on the results obtained from the in vitro performed in Aim 3. Analogs that are the most efficacious in terms of enhancer activity, the least toxic, and exhibit minimal inhibition of cyclooxygenase -1 and -2 will be tested in vivo.