A study on mechanism underlying the inhibition of berberine on proliferation of human melanoma A375 cells

Objective To evaluate the effect of berberine on the expression of cell cycle-related miRNA and its target gene in human melanoma A375 cells. Methods In vitro cultured A375 cells were classified into several groups to be treated with berberine at different concentrations of 0 (blank control group) , 20, 40, 60, 80, and 100 μmol/L, respectively, for 48 hours. qRT-PCR was performed to determine the mRNA expression of miRNA-582-5p and its target gene cyclin-dependent kinase 1 (CDK1) , miRNA-188-5p and its target gene CDK2, Cyclin D1 and Cyclin A. Western blot analysis was conducted to measure the protein expression of cell cycle-related proteins CDK1, CDK2, Cyclin D1 and Cyclin A. Results qRT-PCR showed that compared with the blank control group, the 20 and 40 μmol/L berberine groups had a similar expression of miRNA-582-5p (both P > 0.05) , but the 60 and 80 μmol/L berberine groups had a significantly up-regulated expression of miRNA-582-5p (both P < 0.05) . Compared with the blank control group, all the 5 berberine groups had a significantly increased expression of miRNA-188-5p (F= 22.600, P= 0.002) . However, the mRNA expression of CDK2, CDK1, Cyclin A and Cyclin D1 gradually decreased along with the increase of berberine concentrations (F= 51.976, 248.510, 626.671 and 312.740, respectively, all P < 0.001) . Western blot analysis revealed that berberine decreased the protein expression of CDK1, CDK2, Cyclin D1 and Cyclin A (F= 138.124, 110.966, 278.772 and 140.167, all P < 0.001) . Conclusion Berberine can decrease the expression of cell cycle-related proteins CDK1, CDK2, Cyclin D1 and Cyclin A, likely by decreasing their mRNA expression and increasing the expression of miRNA-582-5p and miRNA-188-5p, and then block the cell cycle progression of A375 cells and inhibit the growth of tumor. Key words: Berberine; Melanoma; MicroRNAs; Cyclins; Cyclin-dependent kinases; A375 cells