A bifunctional anti-enterovirus compound that inhibits replication and the early stage of enterovirus 71 infection

Enviroxime is an anti-enterovirus compound that targets viral protein 3A and/or 3AB and suppresses a replication step of enterovirus by an unknown mechanism. To date, a number of anti-enterovirus compounds that have little structural similarity to enviroxime but induce common resistance mutations in the 3A-encoding region have been identified. The present study identified a novel type of functionally enviroxime-like compound, AN-12-H5. This compound had no structural similarity to enviroxime or to known enviroxime-like compounds, including TTP-8307, GW5074 and Flt3 Inhibitor II. A resistance phenotype of poliovirus (PV) to these compounds was conferred by a major enviroxime-resistance mutation of PV (G531 8A, 3A-Ala70Thr), but not by resistance mutations to guanidine hydrochloride and brefeldin A. AN-12-H5 had a common structure with the anti-enterovirus 71 (EV71) compound AN-23-F6. AN-12-H5 and AN-23-F6 inhibited an early stage of EV71 infection after virus binding to the cells. Mutations in capsid proteins (G3112A, VP1-Ala224Thr, and G2396A, VP3-Arg227Lys mutations) were determined as resistant mutations to AN-12-H5 and AN-23-F6 in the early stage of EV71 infection. These results suggest that AN-12-H5 is a bifunctional anti-enterovirus compound that belongs to a novel class of enviroxime-like compounds and targets both a replication step and an early stage of EV71 infection.