Coomar Seemon, Gasser Jessica A, Słabicki Mikołaj, Donovan Katherine A, Fischer Eric S, Ebert Benjamin L, Gillingham Dennis, Thomä Nicolas H
Friedrich Miescher Institute for Biomedical Research Fabrikstrasse 24 Basel 4056 Switzerland.
Broad Institute of MIT and Harvard Cambridge MA 02142 USA.
RSC Med Chem. 2025 May 6. doi: 10.1039/d5md00054h.
Targeted protein degradation has emerged as a promising approach in drug discovery, utilizing small molecules like molecular glue degraders to harness the ubiquitin-proteasome pathway for selective degradation of disease-driving proteins. Based on results from proteomics screens we investigated the potential of niclosamide, an FDA-approved anthelmintic drug with a 50 year history in treating tapeworm infections, as a molecular glue degrader targeting the proto-oncogene cyclin D1. Proteomics screens in HCT116 colon carcinoma and KELLY neuroblastoma cells, found that niclosamide induces rapid cyclin D1 degradation through a mechanism involving the ubiquitin-proteasome pathway. A genetic CRISPR screen identified the E3 ligase CRL4 as a key player in this process. Structure-activity relationship studies highlighted critical features of niclosamide necessary for cyclin D1 degradation, demonstrating a correlation between mitochondrial membrane potential (MMP) disruption and cyclin D1 downregulation. Notably, various mitochondrial uncouplers and other compounds with similar drug sensitivity profiles share this correlation suggesting that MMP disruption can trigger cyclin D1 degradation, and that the cellular signal driving the degradation differs from previously described mechanism involving CRL4. Our findings underscore the complexities of proteostatic mechanisms and the multitude of mechanisms that contribute to degrader drug action.
靶向蛋白质降解已成为药物研发中一种很有前景的方法，利用分子胶降解剂等小分子来利用泛素-蛋白酶体途径选择性降解驱动疾病的蛋白质。基于蛋白质组学筛选结果，我们研究了氯硝柳胺（一种已获美国食品药品监督管理局批准、有50年治疗绦虫感染历史的驱虫药）作为靶向原癌基因细胞周期蛋白D1的分子胶降解剂的潜力。在HCT116结肠癌细胞和KELLY神经母细胞瘤细胞中进行的蛋白质组学筛选发现，氯硝柳胺通过一种涉及泛素-蛋白酶体途径的机制诱导细胞周期蛋白D1快速降解。一项基因CRISPR筛选确定E3连接酶CRL4是这一过程中的关键参与者。构效关系研究突出了氯硝柳胺对细胞周期蛋白D1降解所必需的关键特征，证明线粒体膜电位（MMP）破坏与细胞周期蛋白D1下调之间存在相关性。值得注意的是，各种线粒体解偶联剂和其他具有相似药物敏感性特征的化合物都存在这种相关性，这表明MMP破坏可触发细胞周期蛋白D1降解，且驱动降解的细胞信号不同于先前描述的涉及CRL4的机制。我们的研究结果强调了蛋白质稳态机制的复杂性以及导致降解剂药物作用的多种机制。
