ABSTRACT
Objective To evaluate the effects of metformin on transforming growth factor-betal (TGF-β 1)-induced epithelial-mesenchymal transition (EMT) in and invasion of the human melanoma cell line 1205Lu.Methods In vitro cultured 1205Lu cells were divided into 3 groups to be treated with serumfree culture medium (blank control group),serum-free culture medium containing 5 ng/ml TGF-β 1 (TGF-β 1 group) and serum-free culture medium containing 5 ng/ml TGF-β 1 and 1 mmol/L metformin (TGF-β1 + metformin group),respectively.After 48-hour treatment,morphological changes of 1205Lu cells in the above groups were observed by using a microscope,and photos were taken at the same time.Transwell invasion assay was performed to estimate cellular invasive activity,Western blot analysis and real-time fluorescence-based quantitative RT-PCR were conducted to determine the mRNA and protein expression of N-cadherin and matrix metalloproteinase-9 (MMP-9),respectively.Statistical analysis was carried out by one-way analysis of variance (ANOVA) and least significant difference (LSD) test.Results Compared with the blank control group,the stimulation of TGF-β 1 could induce the epithelial-mesenchymal transition (EMT)-like morphological changes in 1205Lu cells,while TGF-β 1 combined with metformin could reverse the EMT-like morpho-logical changes.The number of 1205Lu cells crossing the transwell Matrigel per high-power field (× 200) was significantly higher in the TGF-β1 group (412.2 ± 13.427) than in the blank control group (194.1 ± 8.295) and TGF-β1 + metformin group (175.3 ± 8.693).Compared with the blank control group and TGF-β1 + metformin group,the TGF-β1 group also showed significantly increased mRNA and protein expression of N-cadherin (mRNA:6.678 ± 0.043 vs.1.000 ± 0.000,1.035 ± 0.015;protein:1.963 ± 0.016 vs.0.603 ± 0.029,0.207 ± 0.009) and MMP-9 (mRNA:5.351 ± 0.604 vs.1.000 ± 0.000,0.930 ±0.130;protein:1.243 ± 0.027 vs.0.575 ± 0.009,0.629 ± 0.008).Conclusion Metformin can obviously inhibit TGF-β1-induced EMT-like morphological changes in,the capacity to penetrate Matrigel-coated transwell chambers of and the mRNA and protein expression of N-cadherin and MMP-9 in 1205Lu cells.