Hepatitis C virus nonstructural 5A protein inhibits the starvation‑induced apoptosis of hepatoblastoma cells by increasing Beclin 1 expression.

Hepatitis C virus (HCV) nonstructural protein 5A (NS5A) modulates cellular apoptosis, which is involved in the occurrence and development of liver cancer. The mechanisms of apoptosis inhibition by NS5A in liver cancer cells remains unclear. Beclin 1, which functions upstream of autophagosome formation, is upregulated by NS5A. Autophagy, an evolutionarily conserved catabolic process, has a crucial role in tumor initiation and progression. Autophagy was blocked by inhibitors 3‑methyladenine and chloroquine, or via knockdown of Beclin 1. Flow cytometric analysis and western blotting were used to detect apoptosis. It was found that inhibition of autophagy attenuated the NS5A‑mediated apoptosis inhibition of HepG2 cells. Furthermore, it was confirmed that Beclin 1 expression by NS5A was involved in the negative regulation of starvation‑induced liver cancer apoptosis, which was accompanied by reduced p53 and apoptosis regulator Bax expression, as well as decreased caspase‑3/-7 activation. Therefore, inhibition of autophagy may be promising therapeutic strategy in the treatment of HCV‑associated liver cancer.