Novel nucleoside analogue FNC is effective against both wild-type and lamivudine-resistant HBV clinical isolates.
BACKGROUND
HBV infection causes major public health problems worldwide. The clinical limitation of current antiviral drugs for HBV, such as lamivudine, is causing rapid emergence of drug-resistant viral strains during prolonged antiviral therapy. Therefore, new antiviral drugs are urgently needed to prevent or delay the selection of drug-resistant HBV mutants. A novel cytidine analogue, FNC (2'-deoxy-2'-β-fluoro-4'-azidocytidine), was recently shown to strongly inhibit human HBV and duck HBV (DHBV) replication in vitro and in vivo, respectively. The present study was designed to evaluate the in vitro antiviral activity of FNC against clinical wild-type and lamivudine-resistant HBV isolates in transiently transfected cells.


METHODS
HBV DNA was extracted from serum samples collected both before lamivudine therapy and at the time of viral breakthrough and was amplified by PCR. The amplicon was cloned into a novel expression vector, pHY106, which can initiate the intracellular HBV replication cycle after cell transfection. Following transfection of the cloned amplicon into HepG2 cells, a drug susceptibility assay was performed. Quantitative real-time PCR was used for determining the amount of intracellular HBV DNA, and the effective concentration required to reduce HBV replication by 50% (EC(50)) was calculated.


RESULTS
FNC inhibited the replication of both wild-type and lamivudine-resistant HBV clinical isolates in a dose-dependent manner, with mean ±SD EC(50) values of 0.12 ±0.01 μM and 0.27 ±0.01 μM, respectively.


CONCLUSIONS
FNC is a potential antiviral agent against both wild-type and lamivudine-resistant HBV clinical isolates, and therefore deserves further evaluation for the treatment of HBV infection.
Henan Key Laboratory for Pharmacology of Liver Diseases, Academy of Medical and Pharmaceutical Sciences, Zhengzhou University, China.
Yubing
Y
Zhou
Yan
Y
Zhang
Xiaoang
X
Yang
Jing
J
Zhao
Liyun
L
Zheng
Changyu
C
Sun
Jinhua
J
Jiang
Qinghua
Q
Yang
Qingduan
Q
Wang
Junbiao
J
Chang
D000328:Adult; D000998:Antiviral Agents / Q000494:pharmacology* / Q000633:toxicity; D001386:Azides / Q000494:pharmacology* / Q000633:toxicity; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D003841:Deoxycytidine / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000633:toxicity; D024882:Drug Resistance, Viral / Q000235:genetics; D005838:Genotype; D056945:Hep G2 Cells; D006515:Hepatitis B virus / Q000187:drug effects* / Q000235:genetics* / Q000302:isolation & purification; D006801:Humans; D008297:Male; D014779:Virus Replication / Q000187:drug effects
D000998:Antiviral Agents; D001386:Azides; D003841:Deoxycytidine; C540945:azvudine