Development of Proteasome Selective Inhibitors for Cancer Therapy

项目3的总体目标是在设计小分子合成药物的基础上发现新的抗癌药物 抑制蛋白酶体的胰凝乳酶样活性的分子。蛋白酶体是一种多蛋白水解酶 负责降解蛋白质的复合体，如肿瘤抑制因子p53，细胞周期蛋白依赖的 激酶抑制剂p27和p21以及促凋亡蛋白Bax和1KB。许多肿瘤依赖于 蛋白酶体逃避细胞程序性死亡(细胞凋亡)并存活。大多数人类癌症 有低水平的蛋白酶体底物，如p53，p27和bax，这与 具有肿瘤侵袭性、预后差、对化疗耐药、患者生存时间缩短等特点。 项目3所基于的假设是蛋白酶体选择性抑制剂将阻断 蛋白酶体介导促凋亡蛋白的降解，并将通过以下途径抑制肿瘤生长 诱导细胞凋亡。为了验证这一假设，提出了以下具体目标：1)使用High 吞吐量筛选(HTS)和化学文库设计用于鉴定类凝乳凝乳酶选择性蛋白酶体 抑制剂。2)评估在特定目标1中确定的化合物抑制的效力和选择性 蛋白酶体胰凝乳酶样活性，并将抑制剂的效力与其诱导能力相关联 促进细胞凋亡和细胞周期停滞，抑制恶性转化。以确定蛋白酶体是否 与正常细胞相比，抑制剂对癌细胞具有选择性。3)确定蛋白酶体抑制物是否- 诱导癌细胞的凋亡是由促凋亡蛋白的积聚介导的。4)确定是否 BclXL/Bax需要抑制蛋白酶体凝乳酶样活性(项目4)，以及 MDM2/P53和/或MDMX/P53(项目1)干扰物诱导细胞凋亡。5)评估能力 蛋白酶体抑制剂，选择性抑制类糜蛋白酶活性，诱导细胞凋亡和抑制肿瘤 使用人类肿瘤异种移植的动物模型的生长。进行药效学、组方 治疗和毒性研究。拟议的研究将提供化学探针，使我们能够 增强我们对蛋白酶体如何调节异常信号转导途径的理解，如 IKB/NFKB、MDM2/P53和/或MDMX/P53和BclXL/Bax与肿瘤的生存/死亡密切相关。最终， 这些研究将导致发现凝乳酶样蛋白酶体抑制剂，具有促凋亡和 抗肿瘤活性，并将拓宽可成功治疗的人类肿瘤的光谱。

The overall goal of Project 3 is to discover novel anticancer drugs based on designing small synthetic molecules that inhibit the chymotrypsin-like activity of the proteasome. The proteasome is a multi-protease complex that is responsible for degrading proteins such as the tumor suppressor p53, the cyclin-dependent kinase inhibitors p27 and p21 and the proapoptotic proteins Bax and 1KB. Many tumors are dependent on the proteasome to evade programmed cell death (apoptosis) and survive. The majority of human cancers have low levels of substrates of the proteasome such as p53, p27 and Bax and this has been associated with tumor aggressiveness, poor prognosis, resistance to chemotherapy and shortened patient survival time. The hypothesis upon which Project 3 is based is that proteasome selective inhibitors will block proteasome mediated degradation of pro-apoptotic proteins, andwill suppress tumor growth by inducing apoptosis. To test this hypothesis the following specific aims are proposed: 1) To use high throughput screening (HTS) and chemical library design to identify chymotrypsin-like selective proteasome inhibitors. 2) To evaluate the potency and selectivity of the compounds identified in Specific Aim 1 to inhibit the proteasome chymotrypsin-like activity, and to correlate the inhibitors' potency to their ability to induce apoptosis and cell cycle arrest, and to inhibit malignant transformation. To determine if proteasome inhibitors are selective for cancer cells over normal cells. 3) To determine whether proteasome inhibitor- induced cancer cell apoptosis is mediated by accumulation of pro-apoptotic protein. 4) To determine if suppression of the proteasome chymotrypsin-like activity is required for BclXL/Bax (Project 4), and mdm2/p53 arid/or mdmx/p53 (Project 1) disrupters to induce apoptosis. 5) To evaluate the ability of proteasome inhibitors, that selectively inhibit chymotrypsin-like activity, to induce apoptosis and inhibit tumor growth in animal models using human tumor xenografts. To carry out pharmacodynamic, combination therapy and toxicity studies. The studies proposed will provide the chemical probes that will allow us to enhance our understanding of how the proteasome regulates aberrant signal transduction pathways such as IKB/NFKB, mdm2/p53 and/or mdmx/p53 and BclXL/Bax that are critical to tumor survival/death. Ultimately, the studies will lead to the discovery of chymotrypsin-like proteasome inhibitors with proapoptotic and antitumor activities, and will broaden the spectrum of human tumors that can be successfully treated.