CD133(+)EpCAM(+) Phenotype Possesses More Characteristics of Tumor Initiating Cells in Hepatocellular Carcinoma Huh7 Cells

Background: EpCAM or CD133 has been used as the tumor initiating cells (TICs) marker in hepatocellular carcinoma (HCC). We investigated whether cells expressing with both EpCAM and CD133 surface marker were more representative for TICs in hepatocellular carcinoma Huh7 cells. Methods: Four different phenotypes of CD133(+)EpCAM(+), CD133(+)EpCAM(-), CD133(-)EpCAM(+) and CD133(-)EpCAM(-) in Huh7 cells were sorted by flow cytometry. Then cell differentiation, self-renewal, drug-resistance, spheroid formation and the levels of stem cell-related genes were detected to compare the characteristics of TICs. The ability of tumorigenicity was measured in nonobese diabetic/severe combined immunodeficient (NOD/SCID) mice to verify TICs. Results: CD133(+)EpCAM(+) cells have many characteristics of TICs in Huh7 cells compared with CD133(+)EpCAM(-), CD133(-)EpCAM(+), CD133(-)EpCAM(-) cells, including enrichment in side population cells, higher differentiation capacity, increased colony-formation ability, preferential expression of stem cell-related genes, appearance of drug-resistant to some chemotherapeutics, more spheroid formation of culture cells and stronger tumorigenicity in NOD/SCID mice. Conclusion: CD133(+)EpCAM(+) phenotype is precisely represented TICs in Huh7 cells. It might be useful for studying biology mechanism of TICs in hepatocellular carcinoma and screening new targets for cancer therapy.