RWJ-56110 dihydrochloride is a potent, selective, peptide-mimetic inhibitor of PAR-1 activation and internalization (binding IC50=0.44 μM), showing no effect on PAR-2, PAR-3, or PAR-4. It inhibits the aggregation of human platelets induced by SFLLRN-NH2 (IC50=0.16 μM) and thrombin (IC50=0.34 μM), with high selectivity relative to U46619. RWJ-56110 dihydrochloride also blocks angiogenesis and the formation of new vessels in vivo, and induces cell apoptosis[1][2].

Platelet aggregation (human, thrombin-induced):0.34 μM (IC50), PAR1:0.44 uM (IC50), Platelet aggregation (human, SFLLRN-NH2-induced):0.16 μM (IC50)

Proteinase-activated receptors (PARs) are a family of G protein-coupled receptors activated by the proteolytic cleavage of their N-terminal extracellular domain, exposing a new amino-terminal sequence that functions as a tethered ligand to activate the receptors. RWJ56110 inhibits the aggregation of human platelets induced by SFLLRN-NH2 (IC50=0.16 μM) and thrombin (IC50=0.34 μM), while being selective relative to collagen and the thromboxane mimetic U46619 [1]. RWJ-56110 dihydrochloride fully inhibits thrombin-induced RASMC proliferation (IC50=3.5 μM) and blocks thrombin's action on RASMC (IC50=0.12 μM), HMVEC (IC50=0.13 μM), and HASMC calcium mobilization (IC50=0.17 μM) [1]. RWJ56110 (0.1-10 μM; 24-96 hours) inhibits endothelial cell growth dose-dependently, with a half-maximal inhibitory concentration of approximately 10 μM [2]. RWJ56110 (0.1-10 μM; 6 hours) inhibits DNA synthesis of endothelial cells in thymidine incorporation assays, primarily in fast-growing cells (50-60% confluence), while its effect is less pronounced in quiescent cells (100% confluent) [2]. RWJ56110 (0.1-10 μM; pretreatment for 15 min) inhibits thrombin-induced Erk1/2 activation concentration-dependently, and partially reduces Erk1/2 activation levels when endothelial cells are stimulated by FBS (final concentration 4%) [2]. RWJ56110 (30 μM; 24 hours) inhibits endothelial cell cycle progression, reducing the percentage of cells in S phase, with less pronounced alterations in G1 and G2/M phases [2]. Western Blot Analysis [2] Cell Line: Endothelial cells.