Peroxiredoxin 3 is resistant to oxidation-induced apoptosis of Hep-3b cells

Abstract

Although peroxiredoxin 3 (PRX3) was reported to be overexpressed in liver cancer, the precise function of PRX3 in the development and/or progression of liver cancer remained to be obscure. The present study was conducted to investigate the response of PRX3 to oxidative stress in hepatocellular carcinoma (HCC) cells. After successful knockdown of PRX3 expression by small interfering RNA, we treated HCC cell lines Hep-3b and Hep-G2 with gradient concentrations of H2O2 and detected cell proliferation, apoptosis, and the level of reactive oxygen species (ROS) in the cells. After low-dose (5-20 μmol/l) H2O2 treatment, the ROS level was significantly higher in PRX3-knockdown Hep-3b cells than in controls. In addition, PRX3 down-regulation resulted in decreased proliferation, increased apoptosis, and increased caspase 3 activity of Hep-3b cells. We did not notice significant difference between PrxIII knockdown and control Hep-G2 cells in ROS level, cell viability or apoptosis. Our results suggest that PRX3 is an indispensable ROS scavenger that protects tumor cells against oxidative damage and subsequent apoptosis, which provides a clue that PRX3 may be involved in the chemotherapeutic resistance of liver cancer. The underlying mechanism for PRX3 function needs further investigation.