Objective: The present aimed to observe the effect of phosphatase inhibitor cyclosporine A on the subcellular location and on expression of HBcAg in HepG2.2.15 cells.
Methods: Thirty micrograms/ml of cyclosporine A (CSA) was added into HepG2.2.15 cell culture system and on days 2 and 4 HBcAg and HBsAg were respectively stained with fluorescent immunocytochemistry and observed under confocal microscope. Cell apoptosis was detected by terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling method.
Results: HBcAg was mostly expressed in cytoplasm in the control HepG2.2.15 cells. After 2 days CSA administration of the expression of HBcAg and HBsAg in cytoplasm significantly decreased and the signals of HBcAg in nucleus increased , whereas the HBcAg was still mainly expressed in nucleus in about 1/4 of the cells. Cell apoptosis was observed in about 30% of the cells.
Conclusion: CSA improves the nuclear entry of core protein. The increase of HBcAg in nucleus was likely to be related with it's phosphorylation and cell aging or apoptosis.