[Inhibition of hepatitis B viral gene expression and replication in vitro by targeted antisense oligonucleotides]

We chose the 2.2. 15 cells as an in vitro cell culture assay system, and identified the surface antigen subtype of hepatitis B virus (HBV) DNA in the cells, by using the amplification of polymerase chain reaction and directed sequencing of amplified products. According to the result of the sequencing, a 16-mer phosphorothioate analogue of the antisense oligonucleotide (PS-ASON) directed against the HBV U5-unique region was synthesized and then linked with two liver-targeting ligands. The galactosylated human serum albumin coupled poly-L-lysine and the galactosylated poly-L-lysine. The effect of different modifications of ASONs on the expression of HBV gene was compared by using the 2.2. 15 cells. In the same experimental conditions, the inhibitary effects of surface antigen (HBsAg) and antigen (HBeAg) by PS-ASON were 70% and 58% respectively, and those of HBsAg and HBeAg by ligand-PS-ASONs were 90%-96% and 78%-82%. In the same time, the amount of HBV NDA in culture supernatant and cells was depressed significantly. Thus, the ligands targeted ASON to the hepatocytes were more effective inhibitors of HBV gene expression. ASONs were effective and specific inhibitors of HBV replication and expression, caused the dose-dependent inhibition of viral proteins and had no effect on cellular alpha-fetoprotein synthesis and no cytotoxicity.