Discovery, synthesis and biological evaluation of 2-(4-(N-phenethylsulfamoyl)phenoxy)acetamides (SAPAs) as novel sphingomyelin synthase 1 inhibitors

Sphingomyelin synthase (SMS) has been proved to be a potential drug target for the treatment of atherosclerosis. However, few SMS inhibitors have been reported. In this paper, structure-based virtual screening was performed on hSMS1. SAPA 1a was discovered as a novel SMS1 inhibitor with an IC₅₀ value of 5.2 μM in enzymatic assay. A series of 2-(4-(N-phenethylsulfamoyl)phenoxy)acetamides (SAPAs) were synthesized and their biological activities toward SMS1 were evaluated. Among them, SAPA 1j was found to be the most potent SMS1 inhibitor with an IC₅₀ value of 2.1 μM in in vitro assay. The molecular docking studies suggested the interaction modes of SMS1 inhibitors and PC with the active site of SMS1. Site-directed mutagenesis validated the involvement of residues Arg342 and Tyr338 in enzymatic sphingomyelin production. The discovery of SAPA derivatives as a novel class of SMS1 inhibitors would advance the development of more effective SMS1 inhibitors.