Inhibition of hepatitis B virus polymerase by entecavir.
نویسندگان
چکیده
Entecavir (ETV; Baraclude) is a novel deoxyguanosine analog with activity against hepatitis B virus (HBV). ETV differs from the other nucleoside/tide reverse transcriptase inhibitors approved for HBV therapy, lamivudine (LVD) and adefovir (ADV), in several ways: ETV is >100-fold more potent against HBV in culture and, at concentrations below 1 microM, displays no significant activity against human immunodeficiency virus (HIV). Additionally, while LVD and ADV are obligate DNA chain terminators, ETV halts HBV DNA elongation after incorporating a few additional bases. Three-dimensional homology models of the catalytic center of the HBV reverse transcriptase (RT)-DNA-deoxynucleoside triphosphate (dNTP) complex, based on the HIV RT-DNA structure, were used with in vitro enzyme kinetic studies to examine the mechanism of action of ETV against HBV RT. A novel hydrophobic pocket in the rear of the RT dNTP binding site that accommodates the exocyclic alkene moiety of ETV was predicted, establishing a basis for the superior potency observed experimentally. HBV DNA chain termination by ETV was accomplished through disfavored energy requirements as well as steric constraints during subsequent nucleotide addition. Validation of the model was accomplished through modeling of LVD resistance substitutions, which caused an eightfold decrease in ETV susceptibility and were predicted to reduce, but not eliminate, the ETV-binding pocket, in agreement with experimental observations. ADV resistance changes did not affect the ETV docking model, also agreeing with experimental results. Overall, these studies explain the potency, mechanism, and cross-resistance profile of ETV against HBV and account for the successful treatment of naive and LVD- or ADV-experienced chronic HBV patients.
منابع مشابه
Association between KIR Genes and Efficacy of Treatment of HBeAg-Positive Chronic Hepatitis B Patients with Entecavir
Background: Entecavir (ETV) is commonly used to treat chronic hepatitis B (CHB) in China. However, certain percentages of e-Antigen (HBeAg) positive CHB patients do not respond to ETV therapy. Objective: To investigate whether the killer immunoglobulin-like receptor (KIR) genes were associated with seroconversion in HBeAg positive CHB responder patients treated with ETV. Methods: Polymerase cha...
متن کاملThe Discovery and Development of a Potent Antiviral Drug, Entecavir, for the Treatment of Chronic Hepatitis B
Since the first approval of interferon for the treatment of chronic hepatitis B virus (HBV) infection in 1992, six additional antivirals have been developed: pegylated interferon-alfa2a, and the oral antivirals lamivudine, adefovir, telbivudine, entecavir and tenofovir. The availability of animal models for HBV infection and hepatocyte cell culture led to the discovery and development of oral a...
متن کاملInhibition of duck hepatitis B virus replication by mimic peptides in vitro
The aim of the present study was to investigate the inhibitory effect of specific mimic peptides targeting duck hepatitis B virus polymerase (DHBVP) on duck hepatitis B virus (DHBV) replication in primary duck hepatocytes. Phage display technology (PDT) was used to screen for mimic peptides specifically targeting DHBVP and the associated coding sequences were determined using DNA sequencing. Th...
متن کاملEffect of entecavir on CD4+ T-cell subpopulations in patients with chronic hepatitis B.
UNLABELLED Background and aims. CD4+ T cells play an important role in response to hepatitis B virus (HBV) infection. We investigated the change in CD4+ T-cell subpopulations and viral load in patients with chronic HBV infection who were treated with entecavir. MATERIAL AND METHODS Thirty patients with chronic HBV infection were enrolled according to the criteria recommended by the Chinese S...
متن کاملThe polymerase L528M mutation cooperates with nucleotide binding-site mutations, increasing hepatitis B virus replication and drug resistance.
After receiving lamivudine for 3 years to treat chronic hepatitis B, 67-75% of patients develop B-domain L528M, C-domain M552I, or M552V mutations in the HBV polymerase that render hepatitis B virus (HBV) drug-resistant. The aim of this study was to evaluate the influence of these mutations on viral replication and resistance to antiviral agents. We investigated the replication fitness and susc...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
- Journal of virology
دوره 81 8 شماره
صفحات -
تاریخ انتشار 2007