miR-215 promotes malignant progression of gastric cancer by targeting RUNX1

OBJECTIVE: miR-215 was reported to be downregulated and functioned as a tumor suppressor in several cancers. In contrast, miR-215 was preferentially upregulated in gastric cancer (GC) according to our data. Thus, we studied the potential biological function of miR-215 in GC. METHODS: miR-215 expression was measured in 77 paired GC tissues and adjacent non-tumor tissues. Biological functions of miR-215 were analyzed using cell viability, colony formation, migration, invasion, cell cycle, apoptosis and luciferase assays as well as via tumorigenicity and metastasis analysis. RESULTS: miR-215 was significantly upregulated in 7 GC cell lines and 77 GC tissues compared to adjacent non-tumor tissues (P < 0.05), and miR-215 expression was greater in advanced GC (stage III/IV; P < 0.05). Ectopic expression of miR-215 in GES-1 and HGC-27 cells (low miR-215 expression) promoted cell growth, migration, invasion, and metastasis, and these were reversed in NCI-N87 cells (high miR-215 expression) after miR-215 downregulation. Potential target genes of miR-215 were predicted and RUNX1, a transcription factor and a tumor suppressor, was confirmed to be potential target according to luciferase studies. RUNX1 was downregulated in GC tissues compared to adjacent non-tumor tissues (P < 0.05), and RUNX1 reversed partial function of miR-215 in vitro. CONCLUSION: miR-215 promotes malignant progression of GC by targeting RUNX1, and RUNX1 can partially reverse miR-215 effects.