Abstract
BackgroundHepatitis C is a treatment-resistant disease affecting millions of people worldwide. The hepatitis C virus (HCV) genome is a single-stranded RNA molecule. After infection of the host cell, viral RNA is translated into a polyprotein that is cleaved by host and viral proteinases into functional, structural and non-structural, viral proteins. Cleavage of the polyprotein involves the viral NS3/4A proteinase, a proven drug target. HCV mutates as it replicates and, as a result, multiple emerging quasispecies become rapidly resistant to anti-virals, including NS3/4A inhibitors.Methodology/Principal FindingsTo circumvent drug resistance and complement the existing anti-virals, NS3/4A inhibitors, which are additional and distinct from the FDA-approved telaprevir and boceprevir α-ketoamide inhibitors, are required. To test potential new avenues for inhibitor development, we have probed several distinct exosites of NS3/4A which are either outside of or partially overlapping with the active site groove of the proteinase. For this purpose, we employed virtual ligand screening using the 275,000 compound library of the Developmental Therapeutics Program (NCI/NIH) and the X-ray crystal structure of NS3/4A as a ligand source and a target, respectively. As a result, we identified several novel, previously uncharacterized, nanomolar range inhibitory scaffolds, which suppressed of the NS3/4A activity in vitro and replication of a sub-genomic HCV RNA replicon with a luciferase reporter in human hepatocarcinoma cells. The binding sites of these novel inhibitors do not significantly overlap with those of α-ketoamides. As a result, the most common resistant mutations, including V36M, R155K, A156T, D168A and V170A, did not considerably diminish the inhibitory potency of certain novel inhibitor scaffolds we identified.Conclusions/SignificanceOverall, the further optimization of both the in silico strategy and software platform we developed and lead compounds we identified may lead to advances in novel anti-virals.
Highlights
Hepatitis C is a treatment-resistant disease with over 200 million people infected worldwide
We have previously demonstrated that the functional activity of the structurally similar NS2B-NS3 two-component proteinase of West Nile virus (WNV) is efficiently repressed by small molecule allosteric inhibitors [30]
Docking site 3 was selected for targeting because its location in the NS3/4A structure is similar to that in the WNV NS2B-NS3 proteinase structure and because targeting of this site has led us to the discovery of efficient allosteric inhibitors of the WNV proteinase [30] (Fig. 2)
Summary
Hepatitis C is a treatment-resistant disease with over 200 million people infected worldwide. The HCV genome is a single-stranded RNA molecule with positive polarity that is ,9,600 nucleotides in length. After infection of the host cell and liberation of the RNA genome from the protecting virus particle, the viral RNA is translated into a multi-domain polyprotein that is proteolytically cleaved into ten products [1]. The structural proteins are used to assemble new virus particles, while the non-structural (NS) proteins participate in the replication of the viral genome. Hepatitis C is a treatment-resistant disease affecting millions of people worldwide. The hepatitis C virus (HCV) genome is a single-stranded RNA molecule. After infection of the host cell, viral RNA is translated into a polyprotein that is cleaved by host and viral proteinases into functional, structural and non-structural, viral proteins. HCV mutates as it replicates and, as a result, multiple emerging quasispecies become rapidly resistant to anti-virals, including NS3/4A inhibitors
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
