Identification of a novel acylthiourea-based potent broad-spectrum inhibitor for enterovirus 3D polymerase in vitro and in vivo

Abstract

Enterovirus infections have become a serious public health threat to young children, leading to hand-foot-and-mouth disease and more severe nervous system diseases. Due to the lack of licensed anti enterovirus drugs, we reported herein that a Tenovin-1 analog, acylthiourea-based 4-(tert-butyl)-N-((4-(4-(tert-butyl)benzamido)phenyl)carbamothioyl) benzamide (AcTU), displayed low nanomolar anti-EV-A71 activity with an EC₅₀ of 1.0 nM in RD cells. Moreover, AcTU exhibited nanomolar to picomolar inhibitory activity against a series of enteroviruses including EV-D68, CV-A21, CV-A16 and CV-B1 (EC₅₀ = 0.75-17.15 nM). Mechanistic studies indicated that AcTU inhibited enterovirus proliferation by targeting 3D polymerase. In addition, AcTU displayed moderate pharmacokinetic properties in rats (F = 7.4%, T_1/2 = 3.26 h), and in vivo protection studies demonstrated that AcTU orally administered at 0.6 mg/kg/d was highly protective against lethal EV-A71 challenge in mice, potentially reducing mortality from 100% to 20% as well as alleviating symptoms. These results suggested that AcTU could be a potent clinical candidate for the treatment of enterovirus infections.

Keywords: 3D polymerase; Acylthiourea analog; Broad-spectrum; EV-A71; Tenovin-1.