Optimization of a novel class of microtubule stabilizers

微管稳定剂(Msa)是目前使用最广泛和最有效的治疗方法之一。 用于实体肿瘤的治疗。然而，它们的效用受到先天和后天药物的影响。 抵抗。塔卡洛内酯(Tacca)是一类机械上独特的MSA，它可以绕过 多种临床相关的耐药形式。我们的实验室发现了多种有效的塔卡 在药物敏感和耐药的体内模型中具有有效的抗肿瘤活性，但 治疗窗口。这个项目将加深对药物动力学和 这类MSA的药效学研究将产生Taccas，并为将来提供最佳的体内分布 临床发展。与微管蛋白结合的Tacca晶体结构的新一代 杂二聚体为塔卡药效团提供了前所未有的洞察力，这将被用于 实验定义了微管蛋白上的关键残基和Taccas上的部分，这是他们的新发现 微管稳定活性的机制。我们还在塔卡骨骼上发现了可以 半合成修饰以提高化合物的稳定性并优化其药代动力学 和抗肿瘤作用。功能荧光和生物素标记的塔卡已经产生，将 首次允许在体外和体内直接检测Taccas，这将有助于 了解这种独特的MSA的摄取、分布和靶向结合。除了生成 具有更有利药代动力学特征的Taccas及其在分子水平上的疗效评价 患者来源的肿瘤异种移植和同基因模型，我们还将确定相关的生物标志物 对这类新奇的MSA做出回应。一组分子定义的三元组中的表达分析 阴性乳腺癌细胞系发现了与阿司匹林细胞毒效相关的信号通路 塔卡一家。我们将进一步评估这些信号通路的内在变化是否 药物反应的生物标记物，反过来，跟踪数据表明塔卡也可以改变 这些信号通路的功能后果。这些研究具有重要意义，因为它们将 铅，在未来，将产生治疗耐药固体的临床候选药物 并更好地了解它们的作用机制和反应的预测因素。

Microtubule stabilizing agents (MSAs) are some of the most widely used and effective therapies available for the treatment of solid tumors. However, their utility is compromised by innate and acquired drug resistance. The taccalonolides (taccas) are a mechanistically unique class of MSAs that circumvent multiple clinically relevant forms of drug resistance. Multiple potent taccas identified by our laboratories have effective antitumor activity in drug sensitive and resistant in vivo models but suffer from a narrow therapeutic window. This project will develop an in depth understanding of the pharmacokinetics and pharmacodynamics of this class of MSAs that will yield taccas with an optimal in vivo profile for future clinical development. The recent generation of a crystal structure of a tacca bound to tubulin heterodimers has provided unprecedented insight into the tacca pharmacophore, which will be used to experimentally define the critical residues on tubulin and moieties on the taccas that mediate their novel mechanism of microtubule stabilizing activity. We have also identified sites on the tacca skeleton that can be modified semi-synthetically to improve compound stability and optimize their pharmacokinetic profile and antitumor actions. Functional fluorescent and biotin-tagged taccas have been generated that will allow, for the first time, direct detection of the taccas in vitro and in vivo that will be instrumental in understanding the uptake, distribution, and target binding of this unique MSA. In addition to generating taccas with a more favorable pharmacokinetic profile and evaluating their efficacy in molecularly defined patient derived tumor xenograft and syngeneic models, we will also determine biomarkers associated with response to this novel class of MSAs. Expression analysis in a panel of molecularly defined triple negative breast cancer cell lines identified signaling pathways that correlate with the cytotoxic efficacy of the taccas. We will further evaluate whether intrinsic alterations in these signaling pathways are biomarkers of drug response and, reciprocally, follow up on data indicating that the taccas can also alter the functional consequences of these signaling pathways. These studies are significant in that they will lead, in the future, to the generation of a clinical lead candidate for the treatment of drug resistant solid tumors and a greater understanding of their mechanism of action and predictors of response.