Background: Cyclocytidine hydrochloride (HCl) has been reported to inhibit DNA synthesis by affecting DNA polymerase. Here, we tested the antiviral effect of cyclocytidine on hepatitis B virus (HBV) DNA synthesis, which is reliant on DNA polymerase activity.
Materials and methods: Cyclocytidine HCl was treated to HBV-producing HepAD38 cells or added to an endogenous polymerase reaction, and HBV DNA was detected by Southern blot.
Results: Treatment of 20 µM cyclocytidine HCl significantly decreased the production of relaxed circular (rc) DNA in HepAD38 cells and block rcDNA synthesis in endogenous polymerase reaction (EPR), a cell free assay, possibly by inhibiting the HBV DNA polymerase activity.
Conclusion: Cyclocytidine HCl could inhibit the synthesis of HBV rcDNA, the precursor of covalently closed circular DNA, and this result provides a case for the usage of "old" drugs for "new" applications.
Keywords: Chronic hepatitis B; Cyclocytidine hydrochloride; Hepatitis B virus; Relaxed circular DNA.
©2022 Wang et al.