Insufficient radiofrequency ablation promotes hepatocellular carcinoma cell progression via autophagy and the CD133 feedback loop

Insufficient radiofrequency ablation (iRFA) often leads to residual hepatocellular carcinoma (HCC) progression. However, the mechanism is still poorly understood. In the present study, we demonstrated that LC3B protein expression levels were significantly increased in the residual hepatocellular carcinoma cells after radiofrequency ablation (RFA) treatment in vivo. Moreover, iRFA promoted autophagy, autophagosome formation and autophagic flux in Huh-7 and SMMC7721 cell lines in vitro. In addition, iRFA induced HCC cell viability and invasion. However, blockade of autophagy by the autophagosome inhibitor 3-methyladenine (3-MA) suppressed iRFA-induced cell viability and invasion. Furthermore, we revealed that the expression of liver cancer stem cell marker CD133 was also significantly increased in the residual hepatocellular carcinoma cells after RFA treatment in vivo, and was positively correlated with LC3B protein expression. iRFA also promoted CD133 protein expression in Huh-7 and SMMC7721 cell lines in vitro. CD133 was localized to autophagosomes, and was suppressed by 3-MA or chloroquine (CQ) after iRFA treatment. CD133 downregulation also suppressed iRFA-induced cell viability, invasion and autophagy. Collectively, our results indicated that RFA may promote residual HCC cell progression by autophagy and CD133 feedback loop.