miR-203a suppresses cell proliferation by targeting E2F transcription factor 3 in human gastric cancer

MicroRNAs (miRs) are a class of short non-coding RNAs that serve an essential role in the tumorigenesis of gastric cancer (GC). MiR-203a has been reported as a tumor repressor in various types of human cancer. In the present study, the function of miR-203a on the proliferation of GC cells was investigated. Bioinformatics analyses revealed that miR-203a targets the 3'-untranslated region of E2F transcription factor 3 (E2F3) messenger RNA. A luciferase reporter assay and western blot analysis were performed to confirm whether E2F3 was a target of miR-203a. The relative luciferase activity was decreased when overexpressing miR-203a with E2F3-wild type pmirGLO-3'-untranslated region vector, compared with the control group in HEK293 cells. Overexpression of miR-203a suppressed cell proliferation and colony formation of SGC-7901 and AGS GC cells. Inhibition of miR-203a promoted the proliferation of GC cells. Collectively, the results indicated that miR-203a may function as a tumor suppressor in GC by targeting E2F3.