We have previously described several different chemical series of bicyclic prolyl oligopeptidase (POP) inhibitors as probes for neurodegenerative diseases that demonstrated nanomolar activity in vitro and submicromolar activity in cellulo. The more recent implication of POP in cancer, together with homologous fibroblast activation protein α (FAP), implicated in tumor growth, led us to consider developing POP/FAP dual inhibitors as a promising strategy for the development of cancer therapeutics. At this stage, we thought to evaluate the requirements for selectivity of inhibitors for POP over FAP and to evaluate molecular platforms that would enable the development of selective POP and dual POP/FAP inhibitors. We report herein docking-guided design of a new bicyclic scaffold and synthesis of both covalent and non-covalent bicyclic inhibitors. Biological evaluation of first-of-their-kind [4.3.0] bicyclic compounds confirmed that reactive groups, or covalent warheads, are required for inhibitor activity. This work ultimately led to one scaffold yielding new POP-selective inhibitors and a dual inhibitor equipotent to the only drug targeting FAP and POP that ever reached clinical trials.

我们之前已经描述了几种不同化学系列的双环脯氨酰寡肽酶 (POP) 抑制剂作为神经退行性疾病的探针，在体外表现出纳摩尔活性和在纤维素中表现出亚微摩尔活性. 最近 POP 与肿瘤生长相关的同源成纤维细胞活化蛋白 α (FAP) 在癌症中的意义使我们考虑开发 POP/FAP 双抑制剂作为开发癌症治疗的有前景的策略。在这个阶段，我们考虑评估对 POP 抑制剂选择性优于 FAP 的要求，并评估能够开发选择性 POP 和双重 POP/FAP 抑制剂的分子平台。我们在此报告了一种新的双环支架的对接引导设计以及共价和非共价双环抑制剂的合成。首创 [4.3.0] 双环化合物的生物学评估证实，抑制剂活性需要反应基团或共价弹头。