Targeting RNF114 for Cancer Therapy and Targeted Protein Degradation

天然产物一直是对抗癌症的治疗剂的丰富来源，包括广泛使用的 紫杉醇是一种乳腺癌药物，由太平洋紫杉树皮制成，通过靶向微管蛋白来损害 乳腺癌致病性。虽然有无数的天然产品来自植物，微生物， 其他已被证明具有抗癌活性的生物体，大多数的作用机制 对这些天然产物的了解仍然很少。一种这样的天然产物是印楝素，一种三萜类化合物 从印楝或印楝中获得，已被许多研究小组证明具有抗癌活性 针对多种不同类型的癌症，包括乳腺癌，肝细胞癌，结肠癌， 和肾细胞癌。虽然这种天然产品具有引人注目的抗癌特性，但直接 对目标仍然知之甚少。我用了一个创新的化学蛋白质组学平台，叫做活性- 基于蛋白质分析（ABPP），它使用基于反应性的化学探针来映射反应性， 复杂蛋白质组中的功能性和可药用热点，以绘制蛋白质组范围内的可配体 乳腺癌细胞中抗癌天然产物nimbolide靶向的热点。我的初步 使用ABPP的数据表明，在231 MFP中，宁必利选择性靶向E3泛素连接酶RNF 114上的C8 三阴性乳腺癌（TNBC）细胞，导致肿瘤抑制因子p21的泛素化受损 通过削弱RNF 114识别其蛋白质底物的能力。这反过来又导致了一个 p21水平升高，导致乳腺癌细胞致病性受损。在这个建议中，我将使用 创新的化学生物学方法，以确定印楝内酯的抗癌机制， 将RNF 114表征为癌症治疗和靶向蛋白质降解应用的靶标。

Natural products have been a prolific source of therapeutics for combatting cancers, including the widely-used breast cancer drug taxol produced by the bark of the Pacific yew that acts through targeting tubulin to impair breast cancer pathogenicity. While there are countless natural products derived from plants, microbes, and other living organisms that have been shown to exert anti-cancer activity, the mechanism of action of most of these natural products remain poorly understood. One such natural product is nimbolide, a triterpenoid obtained from Azadirachta indica or neem, that has been shown by many groups to exert anti-cancer activity against multiple different types of cancers, including breast cancers, hepatocellular carcinomas, colon cancers, and renal cell carcinomas. While this natural product possesses compelling anti-cancer properties, the direct targets remain poorly understood. I have used an innovative chemoproteomic platform termed activity- based protein profiling (ABPP), which uses reactivity-based chemical probes to map reactive, functional, and druggable hotspots in complex proteomes, to map the proteome-wide ligandable hotspots targeted by the anti-cancer natural product nimbolide in breast cancer cells. My preliminary data using ABPP indicate that nimbolide selectively targets C8 on the E3 ubiquitin ligase RNF114 in 231MFP triple-negative breast cancer (TNBC) cells, leading to impaired ubiquitination of the tumor suppressor p21 through an impairment in the ability of RNF114 to recognize its protein substrates. This in-turn leads to an elevation in p21 levels, leading to impaired breast cancer cell pathogenicity. In this proposal, I will use innovative chemical biology approaches to determine the anti-cancer mechanisms of nimbolide and characterize RNF114 as a target for cancer therapy and for targeted protein degradation applications.