Chemical Inhibitors of the Proteasomal ATPases

蛋白酶体抑制剂现在是多发性骨髓瘤的首选治疗选择之一 并正在对各种其他癌症的临床试验中进行评估。然而， 这些化合物以蛋白酶体的三个活性部位之一为靶点，具有 缺点包括副作用和新出现的耐药性。因此，重要的是要 开发和评估新型蛋白酶体抑制剂。 最近，我们报道了第一个药理成分的发现和表征。 26S蛋白酶体的一种ATPase的抑制物。这六个不同的AAA级 ATPase(称为RPTS 1-6)位于封顶的19S调节颗粒(RP)的碱基上 蛋白酶体的桶状20S核心颗粒(CP)的两端。ATPase 构成将底物引入催化剂中的蛋白质解旋活性 20S CP的内部，还在入口处打开了一个襟翼，否则会阻碍 底物访问。然而，人们对每种蛋白质对 依赖于三磷酸腺苷的展开过程。最近对酵母的研究，其中许多来自我们自己 实验室的研究还表明，这些蛋白质在 RNA聚合酶II转录、DNA修复，或许还有DNA复制。这个 六种ATPase中每一种对所有这些活动的单独贡献尚不清楚。 在这项提案中，我们打算识别和优化这六种药物中的每一种的类肽抑制剂。 蛋白酶体ATPase。将合成和筛选大型类肽文库以 使用为上述抑制剂开发的程序和分析来鉴定命中， 它以Rpt4为靶标。将开发快速优化程序以提高命中率 变成NM的引线。然后这些化合物将被用来确定蛋白酶体是否 ATPase在哺乳动物转录中起着关键作用，就像在酵母中一样。 这些蛋白质的有效抑制物的分离将为未来奠定基础 生物化学实验，剖析每种蛋白质在不同步骤中的作用 转录和蛋白分解。未来的实验还将包括测试它们的活动 在各种癌症小鼠模型中。

Proteasome inhibitors are now one of the first treatment options for multiple myeloma and are being evaluated in clinical trials against a variety of other cancers. However, these compounds, which target one of the three active sites of the proteasome, have drawbacks including side effects and emerging resistance. Therefore, it is important to develop and evaluate novel classes of proteasome inhibitors. Recently, we reported the discovery and characterization of the first pharmacological inhibitor of one of the ATPases of the 26S proteasome. These six different AAA class ATPases (called Rpts 1-6) are located at the base 19S regulatory particle (RP) that caps each end of the barrel-like 20S core particle (CP) of the proteasome. The ATPases constitute a protein unwinding activity that acts to introduce substrates into the catalytic interior of the 20S CP and also holds open a flap at the entrance that otherwise impedes substrate access. However, little is known about the contribution of each protein to the ATP-dependent unfolding process. Recent studies in yeast, many from our own laboratory, have also shown that these proteins play important, non-proteolytic roles in RNA polymerase II transcription, DNA repair and perhaps DNA replication. The individual contributions of each of the six ATPases to all of these activities are unclear. In this proposal, we intend to identify and optimize peptoid inhibitors of each of the six proteasomal ATPases. Large peptoid libraries will be synthesized and screened to identify hits using procedures and assays developed for the inhibitor mentioned above, which targets Rpt4. Rapid optimization procedures will be developed to improve the hits into nM leads. These compounds will then be utilized to determine if the proteasomal ATPases play a critical role in mammalian transcription, as is the case in yeast. The isolation of potent inhibitors of these proteins will then set the stage for future biochemical experiments to dissect the role of each protein in various steps in transcription and proteolysis. Future experiments would also include testing their activity in various mouse models of cancer.