EPOTHILONE AFFINITY LABELS

抗MT药物由于其 开发为潜在的临床有用的抗肿瘤剂。几 对微管蛋白具有紫杉醇样活性的新天然产物， 最近发现了微管。 其中，epothiones 是最有前途最令人兴奋的 这组化合物可以是 从菌源分离，进行规模化生产， 可行 埃坡霉素A和B已被证明是等效的 紫杉醇刺激微管蛋白组装和竞争性抑制微管蛋白表达 [3 H]紫杉醇结合微管。 埃坡霉素也类似 紫杉醇的抗细胞增殖活性。 但这些 化合物对耐药细胞的活性更强 由于P-糖蛋白多药耐药基因的过度表达， 转运蛋白或改变的β-微管蛋白的表达。 因此，在本发明中， 这些化合物具有克服两种不同的 细胞对紫杉醇耐药的机制。 关于药物与人的免疫系统的相互作用， 微管 这些信息将有助于设计新的和 更好的衍生品 在绑定网站上获得的信息将 也是非常重要的，为今后的工作现场指示 微管蛋白的诱变。 可以采用多种方法 获取这些信息，包括那些我们 提出，通过以下方式识别结合位点中的肽： 光亲和标记和使用荧光光谱法 研究互动的细节。 微管蛋白结合研究的结果表明， 紫杉醇和埃坡霉素的结合位点是相同的。 但 埃坡霉素是细胞中有效的细胞毒性剂的事实 对紫杉醇有抗药性的细胞， β-微管蛋白，表明这些位点可能是重叠的，而不是 一模一样 计划通过以下步骤制备埃坡霉素亲和标记物： 合成和全合成，并对它们进行评价 组装活性和细胞毒性。 荧光埃博霉素将是 用于研究微管和微管蛋白的相互作用， 埃坡霉素的光亲和性将鉴定配体结合位点， 受体。

Anti-MT drugs continue to receive great interest for their development as potential clinically useful antitumor agents. Several new natural products with taxol-like activity towards tubulin and microtubules have been identified recently. Of these, the epothiones are the most promising and exciting. This group of compounds can be isolated from bacterial source, making large scale production feasible. Epothilone A and B have been shown to be equipotent to taxol in stimulating tubulin assembly and competitively inhibiting [3H]taxol binding to microtubules. The epothilones are also similar to taxol in their anti-cell proliferative activity. However, these compounds have much greater activity toward cells that are resistant to taxol due to the over-expression of the P-glycoprotein multidrug transporter or to the expression of an altered Beta-tubulin. Thus, these compounds have the potential of overcoming two different mechanisms of cell resistance to taxol. Very little is known yet about the interaction of drugs with microtubules. Such information would be useful for designing new and better derivatives. Information obtained on the binding site will also be extremely important for future work on the site directed mutagenesis of the tubulin protein. A variety of approaches can be taken to obtain this information, including those which we are proposing, identification of peptides in the binding site through photo affinity labeling and the use of fluorescence spectroscopy to study detail of the interaction. The results of the tubulin binding studies would suggest that the binding sites for taxol and epothilone are identical. However, the fact that the epothilones are effective cytotoxic agents in cells that are resistant to taxol because of the expression of an altered Beta-tubulin, indicates that the sites may be overlapping rather than identical. It is the plan to prepare epothilone affinity labels through emisynthesis and total synthesis and evaluate them for tubulin assembly activity and cytotoxicity. Fluorescent epothilones will be used to study the interaction with microtubules and tubulin and the epothilone photo affinity will identify the ligand binding sites in the receptor.