Reduced miR-125a-5p expression is associated with gastric carcinogenesis through the targeting of E2F3

Abstract

Emerging evidence suggests that altered expression of microRNAs (miRNAs) is involved in cancer progression. However, the role of miR-125a-5p in gastric carcinogenesis remains unknown. Quantitative real-time PCR analysis revealed that the expression of miR-125a-5p was significantly decreased in >80% of gastric cancer tissues compared with their adjacent non-tumor tissues, and was markedly reduced in ∼95% of intestinal-type gastric cancer tissues. The downregulated miR-125a-5p was significantly associated with gastric cancer metastasis. Ectopic expression of miR-125a-5p substantially inhibited the proliferation, migration and invasion activities of gastric cancer cells. Furthermore, forced expression of miR-125a-5p repressed the activity of a luciferase reporter carrying the 3'-untranslated (3'-UTR) region of E2F3, which was eliminated by mutation of the predicted miR-125a-binding site, indicating that E2F3 may be a potential target gene of miR-125a-5p. These data suggest that by targeting E2F3, miR-125a-5p may be important as a potential tumor suppressor gene in gastric carcinogenesis.