Fig. 6

MiR-34a negatively regulates stem cell-like characteristics of gastric cancer cells by downregulating Bmi-1. a Expression of Bmi-1 and c-Myc was suppressed by miR-34a, while overexpression of c-Myc increased the inhibited expression of Bmi-1. The expression of c-Myc, Bmi-1, and β-actin in the cell lysis was analyzed by Western blot. b Overexpression of Bmi-1 reversed the inhibition of proliferation ability(colony formation) induced by miR-34a upregulation in MKN45 cells and then photographed (upper panel) and quantified (lower panel). c Overexpression of Bmi-1 reversed the inhibition of microsphere formation induced by miR-34a upregulation. Microsphere formation was tested by serum-free suspension culture (upper panel) and quantified (lower panel) in control cells (vector), miR-34a overexpressing cells(miR-34a), cells simultaneously overexpressing Bmi-1 and miR-34a (miR34a+Bmi-1), and Bmi-1 overexpressing cells (Bmi-1). d Overexpression of Bmi-1 reversed the inhibition of migration ability induced by miR-34a upregulation in MKN45 cells. Migration ability of cells was detected by Transwell Assay and then photographed (upper panel) and quantified (lower panel). e Overexpression of Bmi-1 reversed the inhibition of drug resistance induced by miR-34a upregulation in MKN45 cells. Cell viability after treatment with increasing doses of drug EPI for 48 h was determined with CCK-8. f and g Bmi-1 overexpression in MKN45 cells was confirmed by Western blot (f) and miR-34a overexpression in MKN45 cells after infecting by lentivirus containing miR-34a was confirmed by QRT-PCR (g) in control cells (con), miR-34a overexpressing cells (miR-34a), cells simultaneously overexpressing Bmi-1 and miR-34a (miR34a+Bmi-1) and Bmi-1 overexpressing cells (Bmi-1) . Error bars in all panels represent the mean ± SD (*P < 0.05, **P < 0.01)