Dysregulation of the ubiquitin-proteasome systems is a hallmark of various disease states including neurodegenerative diseases and cancer. Ubiquitin C-terminal hydrolase L1 (UCHL1), a deubiquitinating enzyme, is expressed primarily in the central nervous system under normal physiological conditions, however, is considered an oncogene in various cancers, including melanoma, lung, breast, and lymphoma. Thus, UCHL1 inhibitors could serve as a viable treatment strategy against these aggressive cancers. Herein, we describe a covalent fragment screen that identified the chloroacetohydrazide scaffold as a covalent UCHL1 inhibitor. Subsequent optimization provided an improved fragment with single-digit micromolar potency against UCHL1 and selectivity over the closely related UCHL3. The molecule demonstrated efficacy in cellular assays of metastasis. Additionally, we report a ligand-bound crystal structure of the most potent molecule in complex with UCHL1, providing insight into the binding mode and information for future optimization.

中文翻译：

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共价片段筛选和优化鉴定氯乙酰肼支架作为泛素 C 末端水解酶 L1 的抑制剂

泛素-蛋白酶体系统的失调是包括神经退行性疾病和癌症在内的各种疾病状态的标志。泛素 C 末端水解酶 L1 (UCHL1) 是一种去泛素化酶，在正常生理条件下主要在中枢神经系统中表达，但被认为是多种癌症的癌基因，包括黑色素瘤、肺癌、乳腺癌和淋巴瘤。因此，UCHL1 抑制剂可以作为对抗这些侵袭性癌症的可行治疗策略。在此，我们描述了一种共价片段筛选，将氯乙酰肼支架鉴定为共价 UCHL1 抑制剂。随后的优化提供了一个改进的片段，对 UCHL1 具有个位数微摩尔效力，并且对密切相关的 UCHL3 具有选择性。该分子在细胞转移检测中显示出功效。此外，我们报告了与 UCHL1 复合的最有效分子的配体结合晶体结构，为未来优化提供了对结合模式的深入了解和信息。