Development of second-generation small-molecule RhoA inhibitors with enhanced water solubility, tissue potency, and significant in vivo efficacy

Abstract

RhoA, a member of the Rho GTPases, is involved in a variety of cellular functions and could be a suitable therapeutic target for the treatment of cardiovascular diseases. However, few small-molecule RhoA inhibitors have been reported. Based on our previously reported lead compounds, 32 new 2-substituted quinoline (or quinoxaline) derivatives were synthesized and tested in biological assays. Six compounds showed high RhoA inhibitory activities, with IC50 values of 1.17-1.84 μM. Among these, (E)-3-(3-(ethyl(quinolin-2-yl)amino)phenyl)acrylic acid (26 b) and (E)-3-(3-(butyl(quinolin-2-yl)amino)phenyl)acrylic acid (26 d) demonstrated noticeable vasorelaxation effects against phenylephrine-induced contraction in thoracic aorta artery rings, and compound 26 b had good water solubility and showed significant in vivo efficacy, which was similar to that of 5-(1,4-diazepane-1-sulfonyl)isoquinoline (fasudil) in a subarachnoid hemorrhage-cardiovascular model. To the best of our knowledge, compound 26 b is the first example of a small- molecule RhoA inhibitor with potent in vivo efficacy, which could serve as a good lead for designing cardiovascular agents.

Keywords: RhoA inhibitors; cardiovascular agents; subarachnoid hemorrhage; vasorelaxation; water solubility.