Insufficient radiofrequency ablation promotes angiogenesis of residual hepatocellular carcinoma via HIF-1α/VEGFA

The mechanism of rapid growth of the residual tumor after radiofrequency (RF) ablation is poorly understood. In this study, we investigated the effect of hyperthermia on HepG2 cells and generated a subline with enhanced viability and dys-regulated angiogenesis in vivo, which was used as a model to further determine the molecular mechanism of the rapid growth of residual HCC after RF ablation. Heat treatment was used to establish sublines of HepG2 cells. A subline (HepG2 k) with a relatively higher viability and significant heat tolerance was selected. The cellular protein levels of VEGFA, HIF-1α and p-Akt, VEGFA mRNA and secreted VEGFA were measured, and all of these were up-regulated in this subline compared to parental HepG2 cells. HIF-1α inhibitor YC-1 and VEGFA siRNA inhibited the high viability of the subline. The conditioned media from the subline exerted stronger pro-angiogenic effects. Bevacizumab, VEGFA siRNA and YC-1 inhibited proangiogenic effects of the conditioned media...