Generation of a liver targeting fusion interferon and its bioactivity analysis in vitro

The objective of this study was to generate a liver targeting fusion interferon, galactosyl-human serum albumin-interferon alpha2b (G-HSA-IFN) and to evaluate its bioactivity in vitro on HepG2.2.15 cells which express hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg). The cell proliferation was determined by Sulpho Rhodamine B (SRB) staining method and flow cytometry (FCM) assay. Hochest33342 and Propidium Iodide (PI) double staining and Western blot analysis of Bcl-2/Bax were also performed to evaluate cell lethality and apoptosis. The concentrations of HBsAg and HBeAg secreted in culture supernatant were detected using Enzyme-Linked Immunosorbent Assay (ELISA). The results demonstrated that G-HSA-IFN could inhibit the proliferation of HepG2.2.15 cells and the cell cycle was arrested at G0/G1 phase. Western blotting results showed that the expression of Bcl-2 was inhibited in a dose-dependent manner while the expression of Bax was enhanced. The expression of HBsAg was inhibited by G-HSA-IFN in a dose-dependent manner, while no significant inhibiting effect on the expression of HBeAg was observed. Conclusively, G-HSA-IFN could not only significantly inhibit the HBsAg expression and the proliferation of HepG2.2.15 cells, but also induce the apoptosis of the target cells, rendering it a promising drug candidate for hepatitis B.