Novel FXa Inhibitor Identification through Integration of Ligand- and Structure-Based Approaches.

Factor Xa (FXa), a vitamin K-dependent serine protease plays a pivotal role in the coagulation cascade, one of the most interesting targets for the development of new anticoagulants. In the present work, we performed a virtual screening campaign based on ligand-based shape and electrostatic similarity search and protein-ligand docking to discover novel FXa-targeted scaffolds for further development of inhibitors. From an initial set of 260,000 compounds from the NCI Open database, 30 potential FXa inhibitors were identified and selected for in vitro biological evaluation. Compound 5 (NSC635393, 4-(3-methyl-4 H -1,4-benzothiazin-2-yl)-2,4-dioxo- N -phenylbutanamide) displayed an IC50 value of 2.02 nM against human FXa. The identified compound may serve as starting point for the development of novel FXa inhibitors.