Pharmacological Approaches Increasing Thermal Radiosensi

提高热放射敏感性的药理学方法

• 批准号: 6989562
• 负责人: MICHAEL L. FREEMAN
• 金额: $ 32.5万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-07-01 至 2009-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6989562
• 关键词: NAD(P)H dehydrogenase; athymic mouse; cell nucleus; chemical aggregate; drug design /synthesis /production; green fluorescent proteins; heat shock proteins; heat stimulus; hyperthermia; indomethacin; ionizing radiation; neoplasm /cancer transplantation; protein localization; radiation sensitivity; radiopharmacology; radiosensitizer; tissue /cell culture; transfection

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.

该项目将测试以下假设：高温会引起特定的细胞和/或核变化，使细胞对电离辐射敏感。这一假设的推论是，引起与热相同变化的化学或物理试剂也会导致细胞变得对放射敏感。这一假设及其推论的建立为该项目奠定了基础：诱导辐射致敏的药物的鉴定和开发 利用与热休克相同的分子途径，可用于增强中度热疗的放射增敏作用。 目标 1：检验辐射敏感性可以通过细胞核中蛋白质聚集来增加的假设。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，这些蛋白被设计为在细胞核或细胞质中自发聚集。 目标 2：确定增强热放射增敏作用的药物。 NSAID 吲哚美辛是我们的起始化合物。先前的工作已证实吲哚美辛可以充当放射增敏剂和热放射增敏剂的增强剂。其他独立工作表明，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 激活所需的温度，从而可以在其本身不足以激活的温度下获得完整的热休克反应。 目标 3) 确定赋予热放射增敏作用的 inflole 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，以最大限度地提高增强剂活性并最大限度地降低毒性。类似物设计将基于目标 1 和 2 中确定的分子决定因素。也就是说，我们将确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。目标 4：确定目标 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。 将使用两种人类异种肿瘤模型（NSY和HT-29）。测试将通过体内程序核心进行。类似物选择的标准将基于目标3中体外执行的结果。将在体内测试增强子活性最有效、毒性最小且对环氧合酶-1和-2表现出最小抑制的类似物。