MicroRNA-190 regulates FOXP2 genes in human gastric cancer

Objective: To investigate how microRNA-190 (miR-190) regulates FOXP2 genes in gastric cancer (GC) cell line SGC7901. Methods: We identified that miR-190 could target FOXP2 genes by using dual luciferase enzyme assay. Precursor fragment transfection of miR-190 was performed with GC cell line SGC7901 and human gastric mucosal cell line GES-1. miR-190 expression was detected by reverse transcription-polymerase chain reaction (RT-PCR) and FOXP2 protein expression was measured by Western blotting. Results: FOXP2-3'-untranslated region (UTR) in miR-190 transfection group was significantly decreased as compared with other groups. There were no significant differences in fluorescence signals of FOXP2mut-3'-UTR in each group. Therefore, it was assumed that miR-190 can target FOXP2 genes. Through RT-PCR verification, it was observed that the expression level of miR-190 was significantly higher in GC cell line SGC7901 than in human gastric mucosa cell line GES-1 after transfection with miR-190 mimics. The expression level of miR-190 was significantly higher in GES-1 cells than in SGC7901 cells after transfection with miR-190 inhibitors. Western blotting results showed the expression level of FOXP2 was significantly lower in GC cell line SGC7901 than in GES-1 cells. Compared with blank, mimics control, and inhibitors control groups, the miR-190 mimics group showed significantly enhanced proliferation, migration, and invasion abilities, while miR-190 inhibitors group showed decreased abilities toward proliferation, migration, and invasion (P < 0.05). The transcription level of miR-190 and the expression level of FOXP2 in tumor tissues and adjacent normal tissues in GC patients were verified to be consistent with those of cell line experiments. Conclusion: Upregulation of miR-190 can lead to downregulation of FOXP2 protein expression. miR-190 may serve as a potential target for GC diagnosis.