DIVERSE NATURAL PRODUCTS THAT STABILIZE MICROTUBULES

紫杉醇被FDA批准用于卵巢癌、乳腺癌和肺癌的治疗是人类恶性肿瘤治疗的一个重要进展。然而，紫杉醇存在严重的问题；它在许多肿瘤中缺乏治疗活性，它的水溶性，它的毒性，如周围神经病变和中性粒细胞减少症，以及它容易引起耐药性。四种化学结构高度多样化但作用机制与紫杉醇相似的新型天然产物的出现是一个令人兴奋和具有挑战性的前景。这项拨款的三个具体目标是为临床试验的药物选择提供信息。1)确定紫杉醇和其他稳定微管的化合物对信号通路和细胞周期进程的影响。探讨紫杉醇对微管细胞骨架和导致细胞死亡的信号通路的影响之间的关系。鉴别阻断或刺激信号通路的埃泊霉素、迪德莫内酯和刺柳红素化合物。2)在一系列不同耐药机制的紫杉醇耐药细胞系中检测艾替洛酮、迪德莫里酯和刺柳红素的敏感性。培养对这些药物具有耐药性的细胞系，并结合使用定量表达分析，这将允许在分析其耐药性表型时同时对数千个基因的表达水平进行评分。研究小窝蛋白-1的关系，我们已经证明它在一些耐药细胞中被上调，与耐药性的发展有关。3)利用类似物确定埃泊霉素、迪德莫内酯和刺柳皂苷的构效关系（SAR），以确定生物活性的结构要求。利用这些信息来定义药效团，这些药效团是这些药物和紫杉醇共同的，这将有助于设计结构比紫杉醇更简单的新药。

The approval of Taxol by the FDA for ovarian, breast and lung carcinomas has an important advance in the treatment of human malignancies. However, there are serious problems with Taxol; its lack of therapeutic activity in many tumors, its aqueous insolubility, its toxicities such as peripheral neuropathies and neutropenia and its propensity to induce drug resistance. The advent of four new natural products whose chemical structures are highly diverse but whose mechanism of action is similar to that of Taxol, is an exciting and challenging prospect. The three specific objectives of this grant will provide information for the selection of drugs for clinical trials. 1) Determine the effects of Taxol and other compounds that stabilize microtubules, on signaling pathways and cell cycle progression. Investigate the relationship between the effects of Taxol on the microtubule cytoskeleton and on signaling pathways that lead to cell death. Identify among the epothilones, discodermolide and eleutherobin compounds that block or stimulate signaling pathways. 2) Examine the sensitivity of epothilone, discodermolide and eleutherobin in a series of Taxol-resistant cell lines whose mechanisms of resistance vary. Develop cell lines that are resistant to these drugs and incorporate the use of quantitative expression analysis that will allow scoring expression levels of several thousand genes simultaneously in the analysis of their drug resistant phenotypes. Study the relationship of caveolin-1, that we have shown to be upregulated in some drug-resistant cells, to the development of drug resistance. 3) Define the structure activity relationships (SAR) for the epothilones, discodermolide and eleutherobin using analogs to determine the structural requirements for biological activity. Use this information for defining a pharmacophore, that is common to these drugs and Taxol, that will help in the design of new drugs which will be structurally simpler than Taxol.