Abstract: OBJECTIVE: To investigate effects of metformin on proliferation and migration of human breast cancer cell MDA-MB-231 in vitro. METHODS: Cell cultures were divided into four treatment groups:RPMI 1640 medium group and metformin treatment groups (1,2,4 mmol/L). Cell viability was measured at 48 and 72 h after treatment. Morphological changes of cells were observed under inverted microscopes after cells were stained with Giemsa. Effects of metformin on cell migration were detected by wound healing and Transwell assays. RESULTS: The MTT assay showed that metformin at 4 mmol/L significantly inhibited cell viability l for 72 h,and the inhibition rate was (29.83±2.25%). Compared with the control group,the decrease of cell viability was statistically significant (P<0.05). In the 4 mmol/L treatment group,the number of round cells increased,the cell density decreased obviously,and the connection between cells decreased. After treatment with metformin at 4 mmol/L for 48 hours,the cells showed obvious nuclear fragmentation. Wound healing experiment showed that the cell confluence of 2,4 mmol/L treatment groups were obviously lower than that of the control group after 24 h. The wound healing rate of 4 mmol/L treatment group was (52.67±4.48%),which was significantly different from that of the control group (P<0.01). Transwell experiments showed that the number of perforating cells decreased after treated with metformin at the concentration of 2,4 mmol/L for 24 h. The numbers of perforating cells were (61.6±1.6) and (51.3±2.6),which was significantly different from that of the control group (99.3±18.9) (all P<0.05). CONCLUSION: Metformin inhibited proliferation and migration of human breast cancer cell in vitro.

Key words: metformin, in vitro, human breast cancer, MDA-MB-231 cell, cell proliferation, cell migration