In vitro inhibition of HBV replication by a novel compound, GLS4, and its efficacy against adefovir-dipivoxil-resistant HBV mutations.
BACKGROUND
HBV infection continues to be an important worldwide cause of morbidity and mortality. Patients with chronic hepatitis B can be successfully treated using nucleoside/nucleotide analogues. However, drug-resistant HBV mutants frequently arise, leading to treatment failure and progression to liver disease. Here, we report the effects of GLS4, a non-nucleosidic inhibitor that exhibits a novel and highly specific anti-HBV activity.


METHODS
The median inhibitory concentrations (IC(50)s) of GLS4 on HBV were measured by Southern blotting. HBV capsid and core protein levels were detected by immunoblotting. To determine the antiviral activity of GLS4 against adefovir dipivoxil (ADV)-resistant HBV mutants, HepG2 cells transiently transfected with PUC-HBV1.2 plasmids that contained one of three major ADV-resistant mutations (rtA181T, rtA181V and rtN236T) were treated with GLS4. Intracellular HBV replicative intermediates were detected by Southern blotting. The effect on the in vitro assembly of HBV capsid protein was examined using dynamic light scattering and electron microscopy.


RESULTS
The IC(50) of GLS4 was 0.012 μM, which is significantly lower than that of lamivudine (0.325 μM). Immunoblot analysis of HepG2.2.15 cells and transiently transfected HepG2 cells indicated that GLS4 treatment interfered with the formation of core particles (assembly). The ADV-resistant HBV mutant strains were also sensitive to GLS4. Upon examining the in vitro assembly of HBV core protein 149 by electron microscopy, increased aberrant particles were observed after GLS4 treatment.


CONCLUSIONS
GLS4 is a new and unique potential anti-HBV agent that possesses a different mechanism of action than existing therapeutic drugs.
Peking University People's Hospital, Peking University Hepatology Institute, Beijing, China.
Xue-Yan
XY
Wang
Zhen-Man
ZM
Wei
Guo-Yi
GY
Wu
Jiang-Hua
JH
Wang
Ying-Jun
YJ
Zhang
Jing
J
Li
Heng-Hui
HH
Zhang
Xing-Wang
XW
Xie
Xian
X
Wang
Zhao-He
ZH
Wang
Lai
L
Wei
Yu
Y
Wang
Hong-Song
HS
Chen
D000225:Adenine / Q000031:analogs & derivatives* / Q000494:pharmacology; D000998:Antiviral Agents / Q000737:chemistry / Q000494:pharmacology* / Q000633:toxicity; D036022:Capsid Proteins / Q000037:antagonists & inhibitors; D004279:DNA, Viral / Q000187:drug effects; D024882:Drug Resistance, Viral / Q000235:genetics; D056945:Hep G2 Cells; D006515:Hepatitis B virus / Q000187:drug effects* / Q000235:genetics*; D006801:Humans; D020128:Inhibitory Concentration 50; D009154:Mutation; D063065:Organophosphonates / Q000494:pharmacology*; D011743:Pyrimidines / Q000494:pharmacology*; D013844:Thiazoles / Q000494:pharmacology*; D014758:Viral Core Proteins / Q000037:antagonists & inhibitors; D019065:Virus Assembly / Q000187:drug effects; D014779:Virus Replication / Q000187:drug effects*
D000998:Antiviral Agents; D036022:Capsid Proteins; D004279:DNA, Viral; D063065:Organophosphonates; D011743:Pyrimidines; D013844:Thiazoles; D014758:Viral Core Proteins; C588160:ethyl 4-(2-bromo-4-fluorophenyl)-6-(morpholinomethyl)-2-(2-thiazolyl)-1,4-dihydropyrimidine-5-carboxylate; D000225:Adenine; C106812:adefovir dipivoxil