Identification and characterisation of novel small-molecule activators of EPAC1

Abstract

EPAC1 is a cyclic AMP sensor protein involved in a multitude of physiological and pathophysiological processes in the human body and has been recognised as an attractive target for pharmacological regulation. Activation of EPAC1 protein was reported to suppress chronic vascular inflammation, making it a potential therapeutic strategy for the prevention and treatment of cardiovascular disease. While literature describes a range of EPAC1 inhibitors, no selective small-molecule activators of this protein have been reported until the 2017 discovery of the N-acylsulphonamide derivative, I942, in the Yarwood laboratory. The presented study follows up on this finding and aims to identify novel EPAC1 ligands with agonist properties. A two-phase screening approach was employed to detect EPAC1-binding compounds with potential agonist component in a carefully designed library of I942 analogues. Hits from the screen were further analysed in terms of activity, EPAC1-selectivity, and cytotoxicity, using in vitro biochemical assays and cell-based tests, alongside another new class of EPAC1 activators identified in the Yarwood laboratory, benzofuran oxoacetic acid derivatives. In addition to that, the mechanism of ligand-mediated cytotoxicity was investigated. Three novel, selective, small-molecule EPAC1-regulators with agonist properties and good safety profiles were identified, which can serve as promising lead compounds for drug development.