miR-206对三阴性乳腺癌细胞的增殖抑制作用及初步机制研究

目的 探讨miR-206对三阴性乳腺癌细胞MDA-MB-231增殖的影响及其作用机制。方法 转染miR-206 mimic和miR-NC至乳腺癌细胞株MDA-MB-231中，应用实时荧光定量PCR（qRT-PCR）技术检测miR-206相对表达水平；应用MTT法、克隆形成实验检测miR-206对MDA-MB-231细胞增殖能力的影响；流式细胞术检测miR-206对细胞周期的影响；Western blotting进一步验证miR-206对周期相关蛋白CyclinD2的影响。结果 qRT-PCR检测结果显示，miR-206 mimic转染至MDA-MB-231乳腺癌细胞48h后miR-206的相对表达水平为10.2±1.5。MTT法检测结果显示，miR-206 mimic转染至MDA-MB-231乳腺癌细胞6、24、48、72、96h后的增殖抑制率分别为（0±0.01）％、（0.12±0.03）％、（0.21±0.08）％、（0.28±0.11）％ 和（0.39±0.16）％；克隆形成实验结果显示，miR-206 mimic和miR-NC转染至MDA-MB-231乳腺癌细胞2周后的克隆数目分别为106±35和843±143，差异具有统计学意义（P＜0.01）。流式细胞术检测结果显示，miR-206 mimic转染至MDA-MB-231乳腺癌细胞48h后，明显地阻滞细胞周期于G1期；Western blotting检测显示miR-206表达下调了细胞周期蛋白CyclinD2的表达。结论 miR-206明显抑制了三阴性乳腺癌细胞株MDA-MB-231的增殖，其机制可能与下调细胞周期蛋白CyclinD2的表达有关，这将成为乳腺癌临床治疗一个新的靶点。

The inhibitory effects of miR-206 on triple negative breast cancer cell proliferation and its mechanism

Objective To investigate the effect of miR-206 on the proliferation of triple negative breast cancer cell MDA-MB-231 in vitro and its action mechanism.Methods MiR-206 MiR-206 mimic and miR-NC were transfected into MDA-MB-231 breast cancer cell.The expression level of miR-206 was detected by real time quantitative PCR（qRT-PCR）.MTT and colony formation assays were used to detect the effect of miR-206 on breast cancer cell proliferation.Flow cytometry was used to detect the effect on cell cycle.Western blotting was used to analyze the expression of cyclinD2 in breast cancer cell after transfected with miR-206.Results The results of qRT-PCR showed that the relative expression of miR-206 was 10.2 ± 1.5 when MiR-206 mimic was transfected into MDA-MB-231 breast cancer cell for 48h.The inhibition rate of MDA-MB-231 breast cancer cell which was transfected by miR-206 mimic for 6,24,48,72,96h was（0 ±0.01）%,（0.12 ±0.03）%,（0.21 ±0.08）%,（0.28 ±0.11）%,（0.39 ±0.16）%,respectively.The colony formation assays showed that the number of conolies were 106 ±35,843 ± 143 in miR-206 mimic and miR-NC group when they were transfected for two weeks.miR-206 inhibited breast cancer cell growth by blocking the G1/S transition and down-regulated the expression of cyclinD2.Conclusion MiR-206 can significantly inhibit the proliferation of breast cancer cell MDA-MB-231,which might be exert its functions by regulating the cell cycle protein cyclinD2.miR-206 may be a novel therapeutic target for the treatment of breast cancer.