TAXOL--MECHANISMS OF ACTION AND RESISTANCE

描述(申请人提供)：本研究的长期目标 建议是对行动机制有一个透彻的了解 对紫杉醇的耐药性，紫杉醇是一种已知有效的抗肿瘤药物 在治疗人类癌症方面。从所述研究中获得的知识 在这项提案中将提高我们设计紫杉醇类似物的能力 治疗指数，制定逆转或克服耐药性的策略 为了了解紫杉醇和盘状除草剂之间的协同作用 在组织培养细胞中有报道。我们对紫杉醇的理解将应用于 其他天然产品，如Epothilone和Discodermolide，其 作用机制和抵抗机制有很大的相似之处，但不是 与紫杉醇完全相同。研究提案的具体目标 目的：1.确定环磷酰胺B与盘状病毒的结合部位(S)。 并确定这些结合位点和微管之间的关系 紫杉醇的。具有放射性标记的光反应取代基的药物类似物 分子中定义的位置将被用来确定 药物与其靶点微管之间的相互作用。2.调查 药物对紫杉醇、环磷酰胺和盘状核苷耐药的基础 不表达P-糖蛋白的耐药细胞系。微管蛋白包埋 将对突变进行功能改变分析。我们还将确定 如果紫杉醇、伊波硫酮和盘状除草剂优先与单个 β-微管蛋白同型。这些实验将利用新的质量 我们实验室已经开发了一种基于光谱的方法 α-微管蛋白和β-微管蛋白亚型的C-末端多样性分析。3. 确定紫杉醇和盘状除草剂之间的协同作用是否已经 在我们实验室的四种癌细胞系中证明可以归因于 Discodermolide的特殊结构/功能特征。这项研究 将利用独特的盘状钼酸盐类似物在一系列体外和 老鼠实验。

DESCRIPTION (provided by applicant): The long-term objectives of this research proposal are to acquire a thorough understanding of the mechanisms of action and of resistance to Taxol, an antitumor agent that is known to be efficacious in the treatment of human cancer. Knowledge gained from the studies described in this proposal will improve our ability to design Taxol analogs with a better therapeutic index, to develop strategies to reverse or overcome drug resistance and to understand the synergy between Taxol and discodermolide that we have reported in tissue culture cells. Our understanding of Taxol will be applied to other natural products such as the epothilones and discodermolide whose mechanisms of action and resistance have major similarities, but are not identical, to those of Taxol. The specific objectives of the research proposal are to: 1. Define the binding site(s) for epothilone B and discodermolide in the microtubule and determine the relationship between these binding sites and that of Taxol. Drug analogs with radiolabeled photoreactive substituents at defined positions in the molecules will be used to determine the sites of interaction between the drug and its target, the microtubule. 2. Investigate the basis of resistance to Taxol, epothilone and discodermolide in drug resistant cell lines that do not express P-glycoprotein. Tubulin harboring mutations will be analyzed for functional alterations. We will also determine if Taxol, epothilone and discodermolide bind preferentially to a single beta-tubulin isotype. These experiments will take advantage of a new mass spectrometry-based method that has been developed in our laboratory for the analysis of the C-terminal diversity of a- and beta-tubulin isotypes. 3. Determine if the synergism between Taxol and discodermolide that has been demonstrated in four cancer cell lines in our laboratory can be attributed to specific structural/functional characteristics of discodermolide. The study will take advantage of unique discodermolide analogs in a series of in vitroand mouse experiments.