title: Substitution at rt269 in Hepatitis B Virus Polymerase Is a Compensatory Mutation Associated with Multi-Drug Resistance.
abstract: The emergence of compensatory mutations in the polymerase gene of drug resistant hepatitis B virus (HBV) is associated with treatment failure. We previously identified a multi-drug resistant HBV mutant, which displayed resistance towards lamivudine (LMV), clevudine (CLV), and entecavir (ETV), along with a strong replication capacity. The aim of this study was to identify the previously unknown compensatory mutations, and to determine the clinical relevance of this mutation during antiviral therapy. In vitro mutagenesis, drug susceptibility assay, and molecular modeling studies were performed. The rtL269I substitution conferred 2- to 7-fold higher replication capacity in the wild-type (WT) or YMDD mutation backbone, regardless of drug treatment. The rtL269I substitution alone did not confer resistance to LMV, ETV, adefovir (ADV), or tenofovir (TDF). However, upon combination with YMDD mutation, the replication capacity under LMV or ETV treatment was enhanced by several folds. Molecular modeling studies suggested that the rtL269I substitution affects template binding, which may eventually lead to the enhanced activity of rtI269-HBV polymerase in both WT virus and YMDD mutant. The clinical relevance of the rtL269I substitution was validated by its emergence in association with YMDD mutation in chronic hepatitis B (CHB) patients with sub-optimal response or treatment failure to LMV or CLV. Our study suggests that substitution at rt269 in HBV polymerase is associated with multi-drug resistance, which may serve as a novel compensatory mutation for replication-defective multi-drug resistant HBV.
authors: Department of Pharmacology, Center for Cancer Research and Diagnostic Medicine, IBST, School of Medicine, Konkuk University, Seoul, Korea.
authors: Sung Hyun
authors: SH
authors: Ahn
authors: Department of Pharmacology, Center for Cancer Research and Diagnostic Medicine, IBST, School of Medicine, Konkuk University, Seoul, Korea.
authors: Doo Hyun
authors: DH
authors: Kim
authors: Department of Pharmacology, Center for Cancer Research and Diagnostic Medicine, IBST, School of Medicine, Konkuk University, Seoul, Korea.
authors: Ah Ram
authors: AR
authors: Lee
authors: Department of Internal Medicine and Institute of Gastroenterology, Yonsei University College of Medicine, Seoul, Korea.
authors: Beom Kyung
authors: BK
authors: Kim
authors: Department of Pharmacology, Center for Cancer Research and Diagnostic Medicine, IBST, School of Medicine, Konkuk University, Seoul, Korea.
authors: Yong Kwang
authors: YK
authors: Park
authors: Department of Pharmacology, Center for Cancer Research and Diagnostic Medicine, IBST, School of Medicine, Konkuk University, Seoul, Korea; KU Open Innovation Center, Konkuk University, Seoul, Korea.
authors: Eun-Sook
authors: ES
authors: Park
authors: Department of Internal Medicine and Institute of Gastroenterology, Yonsei University College of Medicine, Seoul, Korea.
authors: Sang Hoon
authors: SH
authors: Ahn
authors: Department of Pharmacology, Center for Cancer Research and Diagnostic Medicine, IBST, School of Medicine, Konkuk University, Seoul, Korea; KU Open Innovation Center, Konkuk University, Seoul, Korea.
authors: Gu-Choul
authors: GC
authors: Shin
authors: Department of Pharmacology, Center for Cancer Research and Diagnostic Medicine, IBST, School of Medicine, Konkuk University, Seoul, Korea.
authors: Soree
authors: S
authors: Park
authors: Department of Pharmacology, Center for Cancer Research and Diagnostic Medicine, IBST, School of Medicine, Konkuk University, Seoul, Korea.
authors: Hong Seok
authors: HS
authors: Kang
authors: Departments of Food Science and Engineering, Ewha Womans University, Seoul, Korea.
authors: Jin-Kyu
authors: JK
authors: Rhee
authors: Department of Pharmacology, Center for Cancer Research and Diagnostic Medicine, IBST, School of Medicine, Konkuk University, Seoul, Korea.
authors: Sung-Il
authors: SI
authors: Yang
authors: Department of Bioscience and Biotechnology, Bio/Molecular Informatics Center, Konkuk University, Seoul, Korea.
authors: Youhoon
authors: Y
authors: Chong
authors: Department of Pharmacology, Center for Cancer Research and Diagnostic Medicine, IBST, School of Medicine, Konkuk University, Seoul, Korea; KU Open Innovation Center, Konkuk University, Seoul, Korea; Research Institute of Medical Sciences, Konkuk University, Seoul, Korea.
authors: Kyun-Hwan
authors: KH
authors: Kim
mesh_terms: D000225:Adenine / Q000031:analogs & derivatives / Q000627:therapeutic use; D019943:Amino Acid Substitution / Q000235:genetics; D000998:Antiviral Agents / Q000627:therapeutic use*; D001086:Arabinofuranosyluracil / Q000031:analogs & derivatives / Q000627:therapeutic use; D045744:Cell Line, Tumor; D024921:Drug Resistance, Multiple, Viral / Q000235:genetics*; D015684:Gene Products, pol / Q000235:genetics*; D006147:Guanine / Q000031:analogs & derivatives / Q000494:pharmacology; D006514:Hepatitis B Surface Antigens / Q000378:metabolism; D006513:Hepatitis B e Antigens / Q000378:metabolism; D006515:Hepatitis B virus / Q000187:drug effects* / Q000235:genetics*; D019694:Hepatitis B, Chronic / Q000188:drug therapy / Q000821:virology; D006801:Humans; D019259:Lamivudine / Q000627:therapeutic use; D008826:Microbial Sensitivity Tests; D008958:Models, Molecular; D063065:Organophosphonates / Q000627:therapeutic use; D000068698:Tenofovir / Q000627:therapeutic use; D014779:Virus Replication / Q000187:drug effects
chemical_list: D000998:Antiviral Agents; D015684:Gene Products, pol; D006514:Hepatitis B Surface Antigens; D006513:Hepatitis B e Antigens; D063065:Organophosphonates; C066027:P protein, Hepatitis B virus; D019259:Lamivudine; D001086:Arabinofuranosyluracil; C413685:entecavir; D006147:Guanine; C053001:adefovir; D000068698:Tenofovir; C034935:clevudine; D000225:Adenine