Aberrantly expressed HIF-1α enhances HCC stem cell-like traits via Wnt/β-catenin signaling activation after insufficient radiofrequency ablation.

Abstract

Radiofrequency ablation has become a favorable treatment modality for small hepatocellular carcinoma (HCC) recently; however, insufficient radiofrequency ablation (RFA) was shown to lead to enhanced invasiveness and metastasis of HCC in our previous study, while the underlying molecular mechanism has not been understood. In order to explore the influence of the hypoxic microenvironment on residual cancer and cancer stem cell (CSC)-like characteristics of HCC cells in this process, an in vitro hypoxic model and an insufficient RFA mouse model were established with HCC cancer cell lines. Immunochemistry staining and western blot were used to examine the expression of hypoxia-inducible factor (HIF)-1α and liver CSC markers. The 3D colon formation assay, tumor cell invasion assay, and gene transfection assays were applied to test the change in liver CSC stemness and HCC cell invasion. After insufficient RFA treatment, the upregulated HIF-1α expression was associated with an increase in the CSC-like population in residual cancer. In vitro, hypoxic tumor cells showed aggressive CSC-like properties and phenotypes. Wnt/β-catenin signaling activation was shown to be necessary for the acquisition of liver CSC-like characteristics under hypoxic conditions. Overall, the aberrantly enhanced HIF-1α expression enhanced the liver CSC-like traits via abnormal Wnt/β-catenin signaling activation after insufficient RFA, and the overexpressed HIF-1α would be a vital factor and useful biomarker during the HCC recurrence and metastasis.