中文摘要：

目的研究miR-548c-5p转染乳腺癌MCF-7细胞株后对细胞增殖、迁移及凋亡的影响。方法CCK-8试剂盒检测不同浓度的miR-548c-5p（50、75、100、125、150nmol／L）分别在24、48、72h不同时间点对细胞增殖的影响；miR-548c-5p转染MCF-7乳腺癌细胞株后，荧光定量PCR法检测其转染效率；划痕实验检测细胞迁移能力的变化；流式细胞术分析干扰后细胞周期的变化；荧光显微镜观察转染后乳腺癌细胞凋亡的变化。结果使用RNA干扰技术成功地将miRNA转染入乳腺癌细胞株，使得miR-548c-5p的表达升高。转染后48hmiR-548c-5p浓度为125nmol／L时，对乳腺癌细胞的抑制作用最明显。miR-548c-5p表达上调后细胞G0／G1明显增多，而s期明显减少（P〈0．01），能-定程度上抑制细胞的迁移。荧光显微镜观察发现早期凋亡细胞升高。结论miR-548c-5p通过干扰细胞周期，增加G0／G1期的乳腺癌细胞数，进而抑制细胞增殖。抑制乳腺癌细胞株MCF-7的迁移能力并显著促进其凋亡。miR-548c-5p影响乳腺癌细胞的增殖、迁移和凋亡，有望成为乳腺癌诊疗的靶点之一。

英文摘要：

Objective To investigate the effects of miR-548c-5p on biological behaviors of MCF-7 breast cancer cell line. Methods The growth inhibition rates of human breast cancer MCF-7 cells were determined by CCK-8 kits after treated with different concentrations of miR-548c-5p （50, 75, 100, 125 and 150 nmol/L） at different time points （24, 48 and 72 h）. MCF-7 breast cancer cells were transfected with miR-548c-5p by Lipofectamine 2000 and the transfection efficiency was measured by QRT-PCR method. Cell invasion ability was assessed by scratch assay, cell cycle changes were analyzed by flow cytometry, cell apoptosis was observed by fluorescence microscopy in breast cancer MCF-7 cells after transfection with miR-548c-5p. Results The expression of miR-548c-5p was significantly enhanced after transfection （P 〈 0. 01 ）. MiR-548c-5p significantly inhibited the proliferation of MCF-7 breast tumor cells at 48 h after transfection with the concentration of 125 nmol/L. Compared with controls, cells in G0/G1 phase increased, while cells in S phase decreased（ P 〈 0.01 ）. The invasion ability of MCF-7 cells was suppressed and the early apoptotic cells were increased after transfection. Conclusion MiR-548c-5p can increase G0/G1 phase, inhibit cell proliferation and invasion and induce apoptosis of human breast cancer MCF-7 cells, indicating that miR-548c-5p may be used as a new target for treatment of breast cancer.