CD133 confers cancer stem-like cell properties by stabilizing EGFR-AKT signaling in hepatocellular carcinoma

Abstract Hepatocellular carcinoma (HCC) is the seventh most common malignant tumor and the third leading cause of cancer-related death in the world. Cancer stem cells (CSCs) are a small subpopulation of cells within tumors that drive chemoresistance and tumor recurrence in various cancers. We characterized CSCs in primary HCC and identified CD133 as a CSC surface marker. CD133+ HCC cells displayed more stem cell-like properties, tumor spheroid-forming ability, chemoresistance, migration ability, and tumorigenic capacity than CD133- HCC cells. The biological function and molecular mechanism of CD133 remain unclear. HCC cell lines with a high level of CD133 expression overexpressed EGFR, which is overexpressed in approximately 70% of conventional HCCs. CD133 depletion destabilized EGFR by augmenting EGFR internalization and thus inhibited EGFR-AKT signaling. CD133 would therefore serve to sustain aberrant EGFR-mediated oncogenic signaling. Furthermore, EGFR-deficient CD133+ HCC cells manifested greater sensitivity to anticancer drugs and less spheroid-formation capacity than control CD133+ HCC cells. Our results strongly indicate that CD133 facilitates CSC-like properties by stabilizing EGFR-AKT signaling in HCC. It might therefore be feasible to use CD133 as a novel target to sensitize HCC cells that manifest resistance to EGFR-targeted therapy.