Effect of Bmi-1-mediated NF-κB signaling pathway on the stem-like properties of CD133+ human liver cancer cells

OBJECTIVE: To investigate the impact of Bmi-1-mediated NF-kappa B pathway on the biological characteristics of CD133(+) liver cancer stem cells (LCSCs). METHODS: Flow cytometry was used to isolate CD133(+) LCSC cells from Huh7, Hep3B, SK-hep1, and PLC/PRF-5 cells. CD133(+) Huh7 cells were divided into Control, Blank, Bmi-1 siRNA, JSH-23 ( NF-kappa B pathway inhibitor), and Bmi-1 + JSH-23 groups. The properties of CD133(+) Huh7 cells were detected by the colony-formation and sphere-forming assays. Besides, Transwell assay was applied for the measurement of cell invasion and migration, immunofluorescence staining for the detection of NF-kappa B p65 nuclear translocation, and qRT-PCR and Western blotting for the determination of SOX2, NANOG, OCT4, Bmi-1, and NF-kappa B p65 expression. RESULTS: CD133(+) Huh-7 cells were chosen as the experiment subjects after flow cytometry. Compared with CD133(-) Huh-7 cells, the expression of CD133, OCT4, SOX2, NANOG, Bmi-1, and NF-kappa B p65, the nuclear translocation of NF-kappa B p65, the number of cell colonies and Sphere formation, as well as the abilities of invasion and migration were observed to be increased in CD133(+) Huh-7 cells, which was inhibited after treated with Bmi-1 siRNA or JSH-23, meanwhile, the cell cycle was arrested at the G0/G1 and S phases with apparently enhanced cell apoptosis. Importantly, no significant differences in the biological characteristics of CD133 + Huh-7 cells were found between the Blank group and Bmi-1 + JSH-23 group. CONCLUSION: Down-regulating Bmi-1 may inhibit the biological properties of CD133(+) LCSC by blocking NF-kappa B signaling pathway, which lays a scientific foundation for the clinical treatment of liver cancer.