MECHANISM OF ACTION OF THE VINCA ALKALOIDS

本提案的重点是深入调查 长春花生物碱的作用。 长春花生物碱是一组 化学相关的吲哚-二氢吲哚药物，目前用于 治疗多种癌症。 它们似乎抑制了细胞 生长至少部分是通过破坏微管。 虽然 关于长春花生物碱如何抑制 微管组装在体外，精确的作用机制， 定量动力学术语几乎完全未知， 对长春花能力关系的认识 生物碱抑制微管的聚合， 直接形成微管。 此外， 各个长春花生物碱是不同的，可以想象， 不同的长春花同源物发挥它们的化疗活性， 细胞通过不同机制的组合。 我们的研究战略分为三个具体领域。 一个主要目标是 继续我们实验室先前开始的定量研究 微管组装抑制机制的表征 长春花生物碱 这些研究将涉及动力学表征 微管蛋白的增加和损失在稳态的相对两端 微管在体外，使用微管从几个来源和 不同的分子组成。 第二个目标是描述 长春花生物碱的相互作用， 微管的解聚（原丝股的剥离， 微管末端）。 这种相互作用 长春碱与微管的相互作用导致组装 将确定抑制。 第三个目标是调查 长春花生物碱衍生物的构效关系 单个同源物抑制微管的能力 细胞中的聚合，以及同系物抑制细胞增殖的能力。 生长，使用人细胞系（Hela），其微管特性在 vitro已经被表征。 目的是确定是否 特定的长春花生物碱衍生物在抑制细胞生长中的作用 完全是由于细胞中微管的破坏，或者发生 通过协同抑制微管功能和其他 细胞过程

This proposal focuses on an in-depth investigation into the mechanism of action of the vinca alkaloids. The vinca alkaloids are a group of chemically related indole-dihydroindole drugs that are currently used in the treatment of a number of forms of cancer. They appear to inhibit cell growth at least in part by the disruption of microtubules. Although a considerable amount has been learned about how the vinca alkaloids inhibit microtubule assembly in vitro, the precise mechanism of action in quantitative kinetic terms is almost completely unknown, as is an understanding of the relationship between the ability of the vinca alkaloids to inhibit the polymerization of microtubules, and to destroy preformed microtubules directly. Further, the antitumor specificities of the individual vinca alkaloids are different, and it is conceivable that the different vinca congeners exert their chemotherapeutic activities on cells by a combination of distinct mechanisms. Our research strategies fall into three specific areas. One major aim is to continue studies begun previously in our laboratory on the quantitative characterization of the mechanism of microtubule assembly inhibition by the vinca alkaloids. These studies will involve the kinetic characterization of tubulin addition and loss at the opposite ends of steady-state microtubules in vitro, using microtubules from several sources and of different molecular compositions. The second goal is to characterize the interactions of the vinca alkaloids that result in the direct depolymerization of microtubules (the peeling of protofilament strands at microtubule ends). The relationship between this interaction of vinblastine with microtubules and the interaction that results in assembly inhibition will be determined. The third goal is to investigate the structure-activity-relationship of the vinca alkaloid derivatives in terms of the abilities of individual congeners to inhibit microtubule polymerization in cells, and the abilities of the congeners to inhibit cell growth, using a human cell line (Hela) whose microtubule properties in vitro have been characterized. The purpose is to determine whether the action of a particular vinca alkaloid derivative in inhibiting cell growth is due exclusively to the disruption of microtubules in cells, or occurs through a concerted ability to inhibit microtubule function and other cellular processes.