Abstract: Objective To explore the inhibitory effect of harmine on melanoma A375 cells and its mechanism thereof.Methods (1) Melanoma A375 cells were treated with harmine at 0, 0.5, 1, 2, 5, 10, 20, 50 and 100 mg/L for 48 h in vitro.CCK-8 method was used to detect the cell viability and confirm the experimental concentrations. (2) After the cells were treated with 0, 1, 2 mg/L harmine, the scratch and transwell assays were used to detect the cell migration and invasion ability. Western blot assay was used to detect the expression levels of epithelial mesenchymal transition (EMT) - related protein E-cadherin, N-cadherin, Snail and p53. (3) Three groups of cells were set up. The control group was transfected with empty vector only. The empty vector group was transfected with empty vector after treated with 2 mg/L harmine for 24 h. The Snail transfection group was transfected with Snail cDNA after treated with 2 mg/L harmine for 24 h. The cell migration and invasion ability were detected after the transfection. Results (1) When the concentration of harmine was above 2 mg/L, the survival rate of A375 cells was significantly lower than that of the control group with the increase of harmine concentrations(P < 0.05). Then, the concentrations of 0, 1 and 2 mg/L of harmine were used in the following experiments. (2) With the increase of the harmine concentrations, the number of cells in the scratched area and the number of trans-membrane cells in each group were significantly decreased. The migration and invasion ability of the cells were decreased gradually. The expression levels of E- cadherin and p53 were increased, while the expression levels of N- cadherin and Snail were decreased. (3) Cell transfection experiments showed that the migration and invasion ability of the cells were increased compared with those of empty vector group after transfection with Snail. Conclusion Harmine can inhibit the proliferation of A375 cells and decrease the abilities of metastasis and invasion, which may be achieved by decreasing the expression of Snail after activating the p53, thereby increasing E-cadherin and down-regulating N-cadherin to inhibit the EMT process.

Key words: harmine, melanoma, epithelial mesenchymal transition, Snail