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

• Published in: Frontiers in pharmacology Vol. 13; p. 941522
• Main Authors: Deng, Hui, Zhang, Qianwen, Lei, Qian, Yang, Na, Yang, Kai, Jiang, Jianbing, Yu, Zhiyi
• Format: Journal Article
• Language: English
• Published: Switzerland Frontiers Media S.A 29.08.2022
• Subjects: activity-based protein profiling; anticancer activity; fluorogenic substrate assay; inhibitor discovery; monoacylglycerol lipase; Pharmacology; fluorogenic substrate assay; monoacylglycerol lipase; activity-based protein profiling; anticancer activity; inhibitor discovery
• ISSN: 1663-9812; 1663-9812
• DOI: 10.3389/fphar.2022.941522

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 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 ( , cryptotanshinone) and -carbolines ( and , 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, 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.