MicroRNA-338 inhibits proliferation, migration, and invasion of gastric cancer cells by the Wnt/β-catenin signaling pathway

OBJECTIVE: Emerging evidence suggests aberrant microRNAs (miRNAs) expression is involved in cancer development through multiple. Although miR338 has shown to have tumor suppression ability and anti-migration effects in some cancers, its regulatory role and molecular mechanism in the development of gastric cancer cells yet remains little known. This work aims to investigate miR-338 in regulating Wnt/beta-catenin pathway in epithelial-mesenchymal transition (EMT) in gastric cancers. MATERIALS AND METHODS: Human gastric cancer cells were transfected with either miR338 mimic or erythropoietin-producing hepatocellular (Eph)A2-targeting siRNA. The biological function of miR-338 in gastric cancer cells was investigated using a MTT assay and invasion assay. Western blot assay was used to measure the levels of EphA2, GSK-3 beta, phospho-GSK-3 beta(Ser9), c-Myc, E-cadherin, Vimentin, and beta-catenin of at protein level. RESULTS: Our data showed that miR-338 inhibited proliferation, migration and invasion of human gastric cancer cells. miR-338 affected the Wnt/beta-catenin pathway by increasing p-GSK-3 beta(Ser9) and decreasing GSK-3 beta Ser9 and c-Myc at protein levels. EphA2 protein level was downregulated and positively correlated with EMT markers. Both silencing of EphA2 and transfection with miR-338 mimic resulted in the up-regulation of the EMT molecular marker E-cadherin and down-regulation of Vimentin and beta-catenin at protein levels. CONCLUSIONS: This study indicated that miR-338 is a potential tumor suppressor in gastric cancer and miR-338 inhibited EMT of gastric cancer cells through deactivation of Wnt/beta-catenin signaling targeting at EphA2.