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Inhibitory activity of dioxolane purine analogs on wild‐type and lamivudine‐resistant mutants of hepadnaviruses
Author(s) -
Seignères Béatrice,
Pichoud Christian,
Martin Perrine,
Furman Philip,
Trépo Christian,
Zoulim Fabien
Publication year - 2002
Publication title -
hepatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.488
H-Index - 361
eISSN - 1527-3350
pISSN - 0270-9139
DOI - 10.1053/jhep.2002.35070
Subject(s) - duck hepatitis b virus , hepatitis b virus , biology , lamivudine , dna polymerase , hepadnaviridae , reverse transcriptase , virology , reverse transcriptase inhibitor , mutant , microbiology and biotechnology , nucleoside , dna synthesis , transfection , cell culture , nucleoside analogue , nucleoside reverse transcriptase inhibitor , viral replication , dna , virus , biochemistry , viral load , rna , gene , genetics , antiretroviral therapy
To design combination strategies for chronic hepatitis B therapy, we evaluated in vitro the inhibitory activity of 4 nucleoside analogs, (−)FTC, L‐FMAU, DXG, and DAPD, in comparison with lamivudine (3TC) and PMEA. In a cell‐free assay for the expression of wild‐type duck hepatitis B virus (DHBV) reverse transcriptase, DAPD‐TP was found to be the most active on viral minus strand DNA synthesis, including the priming reaction, followed by 3TC‐TP, (−)FTC‐TP, and DXG‐TP, whereas L‐FMAU‐TP was a weak inhibitor. In cell culture experiments, important differences in drug concentration allowing a 50% inhibition of viral replication or polymerase activity (IC50s) were observed depending on the cell type used, showing that antiviral effect of nucleoside analogs may depend on their intracellular metabolism. IC50s obtained for wild‐type DHBV replication in primary duck hepatocytes were much lower than with DHBV transfected LMH cells. IC50s were also significantly lower in the 2.2.1.5 and HepG2 cells compared with HBV transfected HuH7 cells. Moreover, L‐FMAU inhibited preferentially HBV plus strand DNA synthesis in these cell lines. The antiviral effect of these inhibitors was also evaluated against 3TC‐resistant mutants of the DHBV and HBV polymerases. These mutants were found to be cross resistant to (−)FTC. By contrast, the double DHBV polymerase mutant was sensitive to DXG‐TP and DAPD‐TP. Moreover, both purine analogs remained active against DHBV and HBV 3TC‐resistant mutants in transfected LMH and HepG2 cells, respectively. In conclusion, the unique mechanism of action of these new inhibitors warrants further evaluation in experimental models to determine their capacity to delay or prevent the selection of drug resistant mutants.