MiR-218 Targeting Bmi-1 Inhibits Proliferation of Acute Promyelocytic Leukemia Cells

Abstract

To explore the molecular mechanism by which miR-218 targeting Bmi-1 inhibits the proliferation of acute promyelocytic leukemia (APL) cells. APL cell line HL-60 was transfected by miR-218 and RNA-negative control sequences, respectively. The expression of miR-218 in cells was detected by real-time fluorescence quantitative PCR. The effect of transfected miR-218 on the proliferation of APL cells was detected by MTT assay. Cell apoptosis was detected by flow cytometry. The regulation effect of miR-218 on Bmi-1 expression was determined by Western blot. The correlation of miR-218 expressions with Bmi-1 was analyzed by Spearman test. The targeted relationship between miR-218 and Bmi-1 was verified by luciferase assay. MTT assay showed that the proliferation of HL-60 cells in vitro was inhibited by high expression miR-218 significantly. Flow cytometry showed that the G1 and G2 phase cells increased while the S phase cells decreased after transfected by miR-218. Western blot showed that the level of Bmi-1 protein in HL-60 cells decreased significantly after transfection of miR-218 (P＜0.05). Spearman correlation analysis showed that the mRNA level of miR-218 negatively correlated with the protein content of Bmi-1 (r=-0.326, P＜0.01). Luciferase assay indicated that Bmi-1 could targeted on miR-218 directly. miR-218 can inhibit the proliferation, metastasis and invasion of APL cells, which can be related with the down-regulated of Bmi-1.