title: Selection of replicon variants resistant to ACH-806, a novel hepatitis C virus inhibitor with no cross-resistance to NS3 protease and NS5B polymerase inhibitors.
abstract: We have discovered a novel class of compounds active against hepatitis C virus (HCV), using a surrogate cellular system, HCV replicon cells. The leading compound in the series, ACH-806 (GS-9132), is a potent and specific inhibitor of HCV. The selection of resistance replicon variants against ACH-806 was performed to map the mutations conferring resistance to ACH-806 and to determine cross-resistance profiles with other classes of HCV inhibitors. Several clones emerged after the addition of ACH-806 to HCV replicon cells at frequencies and durations similar to that observed with NS3 protease inhibitors and NS5B polymerase inhibitors. Phenotypic analyses of these clones revealed that they are resistant to ACH-806 but remain sensitive to other classes of HCV inhibitors. Moreover, no significant change in the susceptibility to ACH-806 was found when the replicon cellular clones resistant to NS3 protease inhibitors and NS5B polymerase inhibitors were examined. Sequencing of the entire coding region of ACH-806-resistant replicon variants yielded several consensus mutations. Reverse genetics identified two single mutations in NS3, a cysteine-to-serine mutation at amino acid 16 and an alanine-to-valine mutation at amino acid 39, that are responsible for the resistance of the replicon variants to ACH-806. Both mutations are located at the N terminus of NS3 where extensive interactions with the central hydrophobic region of NS4A exist. These data provide evidence that ACH-806 inhibits HCV replication by a novel mechanism.
authors.affiliation: Achillion Pharmaceuticals, New Haven, CT 06511, USA.
authors.forename: Wengang
authors.initials: W
authors.lastname: Yang
authors.forename: Yongsen
authors.initials: Y
authors.lastname: Zhao
authors.forename: Joanne
authors.initials: J
authors.lastname: Fabrycki
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Hou
authors.forename: Xingtie
authors.initials: X
authors.lastname: Nie
authors.forename: Amy
authors.initials: A
authors.lastname: Sanchez
authors.forename: Avinash
authors.initials: A
authors.lastname: Phadke
authors.forename: Milind
authors.initials: M
authors.lastname: Deshpande
authors.forename: Atul
authors.initials: A
authors.lastname: Agarwal
authors.forename: Mingjun
authors.initials: M
authors.lastname: Huang
mesh_terms: D000998:Antiviral Agents / Q000494:pharmacology*; D045744:Cell Line, Tumor; D024882:Drug Resistance, Viral / Q000235:genetics*; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D014644:Genetic Variation; D016174:Hepacivirus / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics; D006801:Humans; D008958:Models, Molecular; D011480:Protease Inhibitors / Q000494:pharmacology; D012093:Replicon / Q000187:drug effects*; D012641:Selection, Genetic; D017361:Viral Nonstructural Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics; D012697:Serine Endopeptidases; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases; D012324:RNA-Dependent RNA Polymerase
chemical_list: D000998:Antiviral Agents; D004791:Enzyme Inhibitors; D011480:Protease Inhibitors; D017361:Viral Nonstructural Proteins; C084422:NS3 protein, hepatitis C virus; D012697:Serine Endopeptidases; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases; C087036:NS-5 protein, hepatitis C virus; D012324:RNA-Dependent RNA Polymerase