Existing drugs as broad-spectrum and potent inhibitors for Zika virus by targeting NS2B-NS3 interaction

Abstract

Recent outbreaks of Zika virus (ZIKV) highlight an urgent need for therapeutics.The protease complex NS2B-NS3 plays essential roles during flaviviral polyprotein processing, and thus represents an attractive drug target. Here, we developed a split luciferase complementation-based high-throughput screening assay to identify orthosteric inhibitors that directly target flavivirus NS2B-NS3 interactions. By screening a total of 2 816 approved and investigational drugs, we identified three potent candidates, temoporfin, niclosamide, and nitazoxanide, as flavivirus NS2B-NS3 interaction inhibitors with nanomolar potencies. Significantly, the most potent compound, temoporfin, not only inhibited ZIKV replication in human placental and neural progenitor cells, but also prevented ZIKV-induced viremia and mortality in mouse models. Structural docking suggests that temoporfin potentially binds NS3 pockets that hold critical NS2B residues, thus inhibiting flaviviral polyprotein processing in a non-competitive manner. As these drugs have already been approved for clinical use in other indications either in the USA or other countries, they represent promising and easily developed therapies for the management of infections by ZIKV and other flaviviruses.

Neutralization of Acidic Intracellular Vesicles by Niclosamide Inhibits Multiple Steps of the Dengue Virus Life Cycle In Vitro

“…Indeed, niclosamide treatment www.nature.com/scientificreports www.nature.com/scientificreports/ during the first 6 h of infection reduced DENV replication in BHK-21 cells harbouring dengue replicons to a level comparable to that of ribavirin, suggesting that the drug affects viral RNA replication and/or translation independent of its effect on entry, membrane fusion and genome release. Furthermore, we provide evidence that niclosamide impairs the proteolytic activity of DENV NS2B-NS3, which is essential for the initiation of www.nature.com/scientificreports www.nature.com/scientificreports/ viral replication and may explain its effects on DENV genome replication and/or translation, strengthening the findings of Li et al 44 . However, these findings are somewhat contradictory to the results reported by Kao et al 41 , which, using a replicon-based assay, indicated that niclosamide had no effect on DENV genome replication.…”

The A–Z of Zika drug discovery

“…An HTS assay was developed to test compounds that inhibit the interaction between NS3 and the NS2B N-terminal fragment [62]. Then, a library of FDA-approved drugs and investigational drugs (2816 drugs) was screened using this assay, and 23 compounds produced an IC 50 below 15 mM, of which 12 were considered PAINS.…”

“…(a) Envelope glycoprotein inhibitor: nanchangmycin (IC 50 = 0.1 mM) [48]. (b) NS2B-NS3 protease inhibitors: temoporfin (IC 50 = 1.1 mM) [62] and NSC157058 (IC 50 = 0.82 mM) [66]. (c) NS3 helicase inhibitor: suramin (EC 50 = 0.42 mM), which was tested only in a cell-based assay in ZIKV [75].…”

“…(e) NS5 methyltransferase inhibitor: sinefungin (IC 50 = 1.18 mM) [90,91]. 83% of the mice; the mice that survived did not present any signs of neurological disorder [62]. A similar study was done using structure-based virtual screening (VS) of 8277 compounds from the DrugBank database, and the top 100 candidates were identified [63].…”

Drug Repurposing for Viral Infectious Diseases: How Far Are We?

“…Thus, although further studies are needed to evaluate their antiviral efficacy in vivo, they also represent promising candidates for anti-ZIKV repurposing. Finally, structure-based in silico screenings, followed by in vitro and in vivo experimental studies, led to the identification of another antibiotic, novobiocin, and other FDA-approved drugs (including niclosamide and temoporfin), as novel inhibitors of ZIKV that act by targeting the NS3/NS2B protease [11,12]. In another study, nanchangmycin, a polyether of bacterial origin, blocked ZIKV infection in different cell lines as well as in ex vivo midbrain neuron-glia mixed cultures from embryonic mice [13].…”