title: Evaluating the role of macrocycles in the susceptibility of hepatitis C virus NS3/4A protease inhibitors to drug resistance.
abstract: The hepatitis C virus (HCV) infects an estimated 150 million people worldwide and is the major cause of viral hepatitis, cirrhosis, and liver cancer. The available antiviral therapies, which include PEGylated interferon, ribavirin, and one of the HCV NS3/4A protease inhibitors telaprevir or boceprevir, are ineffective for some patients and cause severe side effects. More potent NS3/4A protease inhibitors are in clinical development, but the long-term effectiveness of these drugs is challenged by the development of drug resistance. Here, we investigated the role of macrocycles in the susceptibility of NS3/4A protease inhibitors to drug resistance in asunaprevir, danoprevir, vaniprevir, and MK-5172, with similar core structures but varied P2 moieties and macrocyclizations. Linear and macrocyclic analogues of these drugs were designed, synthesized, and tested against wild-type and drug-resistant variants R155K, V36M/R155K, A156T, and D168A in enzymatic and antiviral assays. Macrocyclic inhibitors were generally more potent, but the location of the macrocycle was critical for retaining activity against drug-resistant variants: the P1-P3 macrocyclic inhibitors were less susceptible to drug resistance than the linear and P2-P4 macrocyclic analogues. In addition, the heterocyclic moiety at P2 largely determined the inhibitor resistance profile, susceptibility to drug resistance, and the extent of modulation by the helicase domain. Our findings suggest that to design robust inhibitors that retain potency to drug-resistant NS3/4A protease variants, inhibitors should combine P1-P3 macrocycles with flexible P2 moieties that optimally contact with the invariable catalytic triad of this enzyme.
authors.affiliation: Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School , Worcester, Massachusetts 01605, United States.
authors.forename: Akbar
authors.initials: A
authors.lastname: Ali
authors.forename: Cihan
authors.initials: C
authors.lastname: Aydin
authors.forename: Reinhold
authors.initials: R
authors.lastname: Gildemeister
authors.forename: Keith P
authors.initials: KP
authors.lastname: Romano
authors.forename: Hong
authors.initials: H
authors.lastname: Cao
authors.forename: Ayşegül
authors.initials: A
authors.lastname: Ozen
authors.forename: Djade
authors.initials: D
authors.lastname: Soumana
authors.forename: Alicia
authors.initials: A
authors.lastname: Newton
authors.forename: Christos J
authors.initials: CJ
authors.lastname: Petropoulos
authors.forename: Wei
authors.initials: W
authors.lastname: Huang
authors.forename: Celia A
authors.initials: CA
authors.lastname: Schiffer
mesh_terms: D002352:Carrier Proteins / Q000037:antagonists & inhibitors*; D024882:Drug Resistance, Viral / Q000187:drug effects*; D016174:Hepacivirus / Q000187:drug effects*; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D047028:Macrocyclic Compounds / Q000737:chemistry* / Q000494:pharmacology; D015394:Molecular Structure; D017361:Viral Nonstructural Proteins / Q000037:antagonists & inhibitors*; D012697:Serine Endopeptidases; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases
chemical_list: D002352:Carrier Proteins; D047908:Intracellular Signaling Peptides and Proteins; D047028:Macrocyclic Compounds; D017361:Viral Nonstructural Proteins; C084422:NS3 protein, hepatitis C virus; D012697:Serine Endopeptidases; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases; C455041:NS4A cofactor peptide, Hepatitis C virus