Discovering monoacylglycerol lipase inhibitors by a combination of fluorogenic substrate assay and activity-based protein profiling

Hui Deng; Qianwen Zhang; Qian Lei; Na Yang; Kai Yang; Jianbing Jiang; Zhiyi Yu

doi:10.3389/fphar.2022.941522

Discovering monoacylglycerol lipase inhibitors by a combination of fluorogenic substrate assay and activity-based protein profiling

Front Pharmacol. 2022 Aug 29:13:941522. doi: 10.3389/fphar.2022.941522. eCollection 2022.

Authors

Hui Deng^{1

2}, Qianwen Zhang¹, Qian Lei^{1

2}, Na Yang^{1

2}, Kai Yang³, Jianbing Jiang⁴, Zhiyi Yu³

Affiliations

¹ Department of Respiratory and Critical Care Medicine, West China Hospital, Sichuan University, Chengdu, Sichuan, China.
² Targeted Tracer Research and Development Laboratory, Precision Medicine Key Laboratory of Sichuan Province & Precision Medicine Center, West China Hospital, Sichuan University, Chengdu, Sichuan, China.
³ Department of Obstetrics and Gynecology, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, China.
⁴ Department of Medicinal Chemistry, School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, China.

Abstract

The endocannabinoid 2-arachidonoylglycerol (2-AG) is predominantly metabolized by monoacylglycerol lipase (MAGL) in the brain. Selective inhibitors of MAGL provide valuable insights into the role of 2-AG in a variety of (patho)physiological processes and are potential therapeutics for the treatment of diseases such as neurodegenerative disease and inflammation, pain, as well as cancer. Despite a number of MAGL inhibitors been reported, inhibitors with new chemotypes are still required. Here, we developed a substrate-based fluorescence assay by using a new fluorogenic probe AA-HNA and successfully screened a focused library containing 320 natural organic compounds. Furthermore, we applied activity-based protein profiling (ABPP) as an orthogonal method to confirm the inhibitory activity against MAGL in the primary substrate-based screening. Our investigations culminated in the identification of two major compound classes, including quinoid diterpene (23, cryptotanshinone) and β-carbolines (82 and 93, cis- and trans-isomers), with significant potency towards MAGL and good selectivity over other 2-AG hydrolases (ABHD6 and ABHD12). Moreover, these compounds also showed antiproliferative activities against multiple cancer cells, including A431, H1975, B16-F10, OVCAR-3, and A549. Remarkably, 23 achieved complete inhibition towards endogenous MAGL in most cancer cells determined by ABPP. Our results demonstrate the potential utility of the substrate-based fluorescence assay in combination with ABPP for rapidly discovering MAGL inhibitors, as well as providing an effective approach to identify potential targets for compounds with significant biological activities.

Keywords: activity-based protein profiling; anticancer activity; fluorogenic substrate assay; inhibitor discovery; monoacylglycerol lipase.