Combinatorial Development of Blood Stable Camptothecins

描述：（改编自申请人的摘要）喜树碱是 广泛用于实体瘤的治疗。两种喜树碱类似物 已经在市场上，其他一些已经处于不同的阶段， 研发的然而，尽管他们的承诺， 喜树碱类似物含有基本的结构倾向：不稳定的 E-环内酯。直到最近，这一领域的教条是， E-环内酯的存在对于生物活性是必不可少的。然而，在这方面， 最近有迹象表明，E形环的功能可以改变， 没有损害，事实上，有好处。这项资助的假设是 仍然需要显著改进的喜树碱衍生物， 下一代喜树碱衍生物应该含有 显示出显著改善的稳定性的内酯或不含 E环内酯。这项资助的目的是发现这些衍生物 通过化学合成修饰的内酯或 喜树碱的非内酯类似物，然后快速测定这些 用于稳定性/化学性质、抑制酶的能力的文库 拓扑异构酶1和抗肿瘤活性。在这一补助金中，我们建议进行 1）合成了A、B、E环修饰的α-羟基 内酯喜树碱，以及探索性和重点图书馆， 非内酯喜树碱。重点图书馆将基于有前途的 在早期的体外分析中已经鉴定的候选物。（二） 表征以下物质的探索性和聚焦文库的体外效价： 利用快速和高效的方法， 高通量MTS测定。本试验将在不存在且 存在生理学相关水平的人血清白蛋白， 确定这种高度丰富的血液蛋白可能对类似物产生的任何影响。 活动显示出优异的上级IC 50值（在10 nM范围内或 在人血清白蛋白的存在下，将选择用于合成 放大和更彻底的体外表征。3)进行彻底的 分析每个模拟物的物理性质，以确保网络稳定性 在更广泛的体内表征之前。4)对比一下铅， 具有FDA批准的喜树碱的血液稳定的喜树碱衍生物， 在携带人肿瘤异种移植物的小鼠中的活性。药代动力学和药物 将确定每种先导剂的代谢参数。

DESCRIPTION: (Adapted from the applicant's abstract) The camptothecins are being widely used in the treatment of solid tumors. Two camptothecin analogs are already on the market and a number of others are in various stages of research and development. However, for all their promise, all known camptothecin analogs contain a fundamental structural liability: the unstable E-ring lactone. Until recently it has been dogma in this field that the presence of the E-ring lactone was essential to biological activity. However, there are recent signs that the functionality in the E-ring can be changed without detriment and, indeed, with benefit. It is the hypothesis of this grant that significantly improved derivatives of camptothecin are still needed and that the next generation of camptothecin derivatives should either contain a lactone displaying markedly improved stability or agents that do not contain the E-ring lactone. It is the aim of this grant to discover these derivatives through the chemical synthesis of focused libraries of modified-lactone or non-lactone analogs of camptothecin followed by the rapid assaying of these libraries for stability/chemical properties, ability to inhibit the enzyme toposisomerase 1, and anti-tumor activity. In this grant we propose to conduct the following experiments: 1) Synthesize A,B,E-ring modified alpha-hydroxy lactone campothecins, as well as exploratory and focused libraries concerning non-lactone camptothecins. The focused libraries will be based on promising candidates that have been identified during the early in vitro analyses. 2) Characterize the in vitro potency of the exploratory and focused library of analogs against 9 distinct human cancer cell lines utilizing a rapid and high-throughput MTS assay. This assay will be performed in the absence and presence of physiologically relevant levels of human serum albumin in order to determine any effect this highly abundant blood protein may exert on analog activity. Analogs displaying superior IC50 values (within the 10 nM range or below) in the presence of human serum albumin will be selected for synthetic scale-up and a more thorough in vitro characterization. 3) Perform a thorough analysis of the physical properties of each analog to ensure the net stability prior to more extensive in vivo characterization. 4) Compare the lead, blood-stable camptothecin derivatives with FDA-approved camptothecins for activity in mice bearing human tumor xenografts. Pharmacokinetic and drug metabolism parameters for each of the lead agents will be determined.