Abstract
In recent decades, considerable advances have been achieved in the treatment of chronic hepatitis B. However, the currently available drugs have shortcomings. In this context, several natural compounds have been proposed as potential agents to improve either the outcome of antiviral treatment or the progression of chronic infection, with curcumin being one of the most evaluated compounds due to its pleiotropic antiviral activity. The aim of this study was to characterize the effect and mechanism of curcumin on hepatitis B virus (HBV) replication in two different experimental models. Treatment of HepG22.15 and HBV-transfected Huh7 cells with curcumin revealed that the phytochemical differentially modulated HBV replication in both cell lines. In HepG22.15 cells, the addition of curcumin had no effect on viral DNA, pregenomic RNA (pgRNA), and e antigen (HBeAg) levels, while it decreased Precore RNA and s antigen (HBsAg) levels. Conversely, in Huh-7 cells, curcumin significantly increased viral progeny more than tenfold, as well as HBV RNAs and viral antigens. Furthermore, the analysis of the cellular mechanisms associated with the modulation of viral replication revealed that in Huh-7 cells, curcumin-induced cell cycle arrest in the G2/M phase and the modulation of genes involved in proliferation, cell cycle progression, and apoptosis, whereas no changes in cell cycle progression and gene expression were observed in HepG22.15 cells. In conclusion, curcumin elicits a differential cellular response in two hepatoma cell lines, which, in the case of Huh-7 cells, would provide an optimal cellular setting that enhances HBV replication. Therefore, the antiviral effect of this phytochemical remains controversial.