The expression of miR-218 in breast cancer tissues and the biological function of miR-218 in breast cancer MCF-7 cells / 肿瘤

ABSTRACT

Objective: To explore the expression of microRNA-21 8 (miR-218) in breast cancer tissues and the effect of miR-218 on the proliferation, apoptosis and cell cycle of breast cancer MCF-7 cells. Methods: The expression levels of miR-218 and B cell-specific MLV integration site 1 (BMN) mRNA in breast cancer tissues and the corresponding adjacent paracancerous tissues were detected by real-time fluorescence quantitative PCR. After miR-218 mimics transfection into MCF-7 cells, the expression levels of miR-218 and BMI1 mRNAs were detected by real-time fluorescence quantitative PCR, the proliferation ability of MCF-7 cells was detected by CCK-8 assay, and the cell cycle distribution and apoptosis were examined by flow cytometry (FCM). Results: The expression level of miR-21 8 in breast cancer tissues was significantly lower than that in corresponding adjacent paracancerous tissues (P < 0.01), and the expression level of BMIl mRNA was opposite (P < 0.05). The expression level of miR-218 in MCF-7 cells after transfection with miR-218 mimics was significantly higher than those in the negative control group [MCF-7 cells transfected with miR-218 negative control (miR-218 NC)] and the blank control group (MCF-7 cells without any transfection) (both P < 0.01), and the expression level of BMIl mRNA was opposite (P < 0.01). The proliferation ability of MCF-7 cells after transfection with miR-21 8 mimics was inhibited (P < 0.05); the proportion of G1-stage cells was decreased while the proportion of S-stage cells was increased, and the apoptosis rate was increased (all P < 0.01). Conclusion: The expression level of miR-218 is down-regulated in breast cancer tissues. miR-218 may inhibit the proliferation of breast cancer MCF-7 cells, promote apoptosis, and affect cell cycle distribution.