Pharmacological Inhibitors of Nedd4 ubiquitin ligase as anticancer therapeutics

 描述（由申请人提供）：蛋白质泛素化是调节人类生物学各个方面的基本生物学过程。多聚泛素链对蛋白质的共价修饰使其标记为蛋白酶体降解，而单泛素化调节内吞作用、信号转导、核输入和基因转录。为此，泛素连接酶（已知约600种）代表了可药用基因组的一个巨大且完全未开发的领域。泛蛋白连接酶的复杂性和多样性可与其他三个大家族相媲美 酶：激酶（~500）、蛋白酶（~600）和GPCR（~800）。有25种FDA批准的激酶抑制剂药物，约30种FDA批准的蛋白酶抑制剂药物，约30%的药物靶向GPCR。与此形成鲜明对比的是，只有3种FDA批准的靶向泛素连接酶的药物：致畸化合物沙利度胺及其类似物来那度胺和泊马度胺。值得注意的是，E3连接酶基因的种系和体细胞突变与许多人类疾病如癌症、自身免疫性疾病、神经退行性疾病和高血压疾病有关。因此，E3连接酶最近已成为基础研究和药物发现的重要靶标。在这项提案中，我们将重点放在开发HECT E3连接酶Nedd 4 -1的小分子抑制剂上，Nedd 4 -1是小鼠的一种必需基因，是IGF-1和胰岛素细胞生长途径的正调控因子，这些途径增加了人类癌症的风险并促进了癌症的生长。具体目的如下：（1）发现Nedd 4 -1的共价抑制剂。我们使用了一种不可逆的网络共享技术， Nedd 4 -1酶的共价抑制剂，并使用X射线晶体学可视化其结合模式。我们建议研究已鉴定的Nedd 4 -1抑制剂的生物化学作用机制，（2）对已鉴定的Nedd 4抑制剂进行结构-活性关系（SAR）研究，（3）对Nedd 4 -1抑制剂进行基于细胞的研究，以显示它们抑制细胞中IGF-1/胰岛素细胞生长途径。总之，拟议的研究计划概述了发现HECT E3泛素连接酶Nedd 4 -1的共价小分子抑制剂的新概念。拟议的研究计划将作为启动新的研究方向的基础，以发现和优化靶向其他HECT E3连接酶（28已知）的小分子探针。

 DESCRIPTION (provided by applicant): Protein ubiquitination is a fundamental biological process that regulates all aspects of human biology. Covalent modification of proteins with polyubiquitin chains tags them for proteasomal degradation, while monoubiquitination regulates endocytosis, signal transduction, nuclear import, and gene transcription. To this end, ubiquitin ligase enzymes (~600 known) represent a vast and completely unexplored area of druggable genome. The complexity and diversity of ubiquitin ligases rivals that of three other large families of enzymes: kinases (~500), proteases (~600), and GPCRs (~800). There are 25 FDA approved kinase inhibitor drugs, ~30 FDA approved protease inhibitor drugs, and about 30% of all medications target GPCRs. In stark contrast, there are only 3 FDA approved drugs that target ubiquitin ligases: teratogenic compounds thalidomide, and its analogues lenalidomide and pomalidomide. Significantly, germline and somatic mutations of E3 ligase genes are linked to many human diseases such as cancers, autoimmune diseases, neurodegenerative diseases, and hypertensive disorders. Therefore E3 ligases have recently emerged as prominent targets for basic research and drug discovery. In this proposal, we focus our efforts on developing small molecule inhibitors of HECT E3 ligase Nedd4-1, which is an essential gene in mice and is a positive regulator of IGF-1 and insulin cell growth pathways, pathways that increase the risk and promote the growth of human cancers. Specific aims are as follows (1) To discover covalent inhibitors of Nedd4-1. We used an irreversible tethering technology, to identify two first-in-class covalent inhibitors of Nedd4-1 enzyme, and visualized their binding mode using X-ray crystallography. We propose to investigate biochemical mechanism of action of identified Nedd4-1 inhibitors, (2) conduct structure-activity relationship (SAR) studies of identified Nedd4 inhibitors, (3) to conduct cell based studies of Nedd4-1 inhibitors to show that they inhibit IGF-1/Insulin cell growth pathways in cells. In summary, the proposed research program outlines new concepts to discover covalent small molecule inhibitors of HECT E3 ubiquitin ligase Nedd4-1. The proposed research program will serve as a foundation to initiate novel research directions to discover and optimize small molecule probes targeting other HECT E3 ligases (28 known).