title: Resistance studies of a dithiazol analogue, DBPR110, as a potential hepatitis C virus NS5A inhibitor in replicon systems.
abstract: Hepatitis C virus (HCV), a member of the Flaviviridae family, affects approximately 3% of the world's population and is becoming the leading cause of liver disease in the world. Therefore, the development of novel or more effective treatment strategies to treat chronic HCV infection is urgently needed. In our previous study, we identified a potential HCV NS5A inhibitor, BP008. After further systemic optimization, we discovered a more potent HCV inhibitor, DBPR110. DBPR110 reduced the reporter expression of the HCV1b replicon with a 50% effective concentration (EC(50)) and a selective index value of 3.9 ± 0.9 pM and >12,800,000, respectively. DBPR110 reduced HCV2a replicon activity with an EC(50) and a selective index value of 228.8 ± 98.4 pM and >173,130, respectively. Sequencing analyses of several individual clones derived from the DBPR110-resistant RNAs purified from cells harboring genotype 1b and 2a HCV replicons revealed that amino acid substitutions mainly within the N-terminal region (domain I) of NS5A were associated with decreased inhibitor susceptibility. P58L/T and Y93H/N in genotype 1b and T24A, P58L, and Y93H in the genotype 2a replicon were the key substitutions for resistance selection. In the 1b replicon, V153M, M202L, and M265V play a compensatory role in replication and drug resistance. Moreover, DBPR110 displayed synergistic effects with alpha interferon (IFN-α), an NS3 protease inhibitor, and an NS5B polymerase inhibitor. In summary, our results present an effective small-molecule inhibitor, DBPR110, that potentially targets HCV NS5A. DBPR110 could be part of a more effective therapeutic strategy for HCV in the future.
authors.affiliation: Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Zhunan Town, Miaoli County, Taiwan.
authors.forename: Hui-Mei
authors.initials: HM
authors.lastname: Lin
authors.forename: Jing-Chyi
authors.initials: JC
authors.lastname: Wang
authors.forename: Han-Shu
authors.initials: HS
authors.lastname: Hu
authors.forename: Pei-Shan
authors.initials: PS
authors.lastname: Wu
authors.forename: Wen-Hung
authors.initials: WH
authors.lastname: Wang
authors.forename: Su-Ying
authors.initials: SY
authors.lastname: Wu
authors.forename: Chi-Chen
authors.initials: CC
authors.lastname: Yang
authors.forename: Teng-Kuang
authors.initials: TK
authors.lastname: Yeh
authors.forename: Tsu-An
authors.initials: TA
authors.lastname: Hsu
authors.forename: Weir-Torn
authors.initials: WT
authors.lastname: Jiaang
authors.forename: Yu-Sheng
authors.initials: YS
authors.lastname: Chao
authors.forename: Jyh-Haur
authors.initials: JH
authors.lastname: Chern
authors.forename: Andrew
authors.initials: A
authors.lastname: Yueh
mesh_terms: D019943:Amino Acid Substitution; D000998:Antiviral Agents / Q000737:chemistry / Q000494:pharmacology*; D045744:Cell Line, Tumor; D024882:Drug Resistance, Viral / Q000235:genetics*; D005838:Genotype; D016174:Hepacivirus / Q000187:drug effects / Q000235:genetics; D019698:Hepatitis C, Chronic / Q000188:drug therapy* / Q000821:virology; D006801:Humans; D016898:Interferon-alpha / Q000494:pharmacology; D009154:Mutation; D011485:Protein Binding; D011759:Pyrrolidines / Q000494:pharmacology*; D012367:RNA, Viral / Q000032:analysis; D012093:Replicon; D017423:Sequence Analysis, RNA; D013844:Thiazoles / Q000494:pharmacology*; D017361:Viral Nonstructural Proteins / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000235:genetics; D012324:RNA-Dependent RNA Polymerase
chemical_list: D000998:Antiviral Agents; D016898:Interferon-alpha; D011759:Pyrrolidines; D012367:RNA, Viral; D013844:Thiazoles; D017361:Viral Nonstructural Proteins; C582392:DBPR110; C087036:NS-5 protein, hepatitis C virus; D012324:RNA-Dependent RNA Polymerase