Abstract: 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.