miR‐212 as potential biomarker suppresses the proliferation of gastric cancer via targeting SOX4

BACKGROUND: Circulating microRNAs that post‐transcriptionally regulate gene expressions have been reported as promising biomarkers in cancer monitoring. This study was to identify the potential role of circulating miR‐212 in gastric cancer and whether it could serve as a novel biomarker for gastric cancer. METHODS: We detected the serum levels of miR‐212 in 100 health people and 110 gastric cancer patients and analyzed the relationships of the serum level of miR‐212 with gastric cancer. We detected the expression of miR‐212 in human gastric mucosal epithelial cell line (GES‐1) and human gastric cancer cell lines (NCI‐N87 and SNU‐16) using qRT‐PCR. Then, we detected the role of 5‐aza‐deoxycytidine on the epigenetic regulation of miR‐212 in human gastric cancer cell lines. Furthermore, luciferase reporter assay was used to detect binding activity of miR‐212 on SOX4 mRNA, and their functions on the cell proliferation and apoptosis. RESULTS: The expression of miR‐212 was higher in health people than that in gastric cancer patients, higher in gastric mucosal epithelial cell line than that in gastric cancer cells. miR‐212 can be a circulating biomarker and an independent prognostic factor of gastric cancer. Moreover, miR‐212 can directly regulate the 3′UTR of SOX4 mRNA to suppress p53 and Bax, resulting gastric cancer cells proliferation inhibition and apoptosis induction. CONCLUSION: Our study demonstrated that miR‐212 was epigenetically downregulated in gastric cancer, and resulting low level of miR‐212 can be a potential circulating biomarker and poor prognosis predicator of gastric cancer.