SKA2 is a direct target gene of miR-520a-3p in GC cells. (A) Sequence alignment of miR-520a-3p with 3′UTR of SKA2 predicted by TargetScan and the Mut 3′UTR miR-520a-3p binding sequence. (B) Luciferase activity of SGC-7901 cells was examined via a luciferase reporter assay. **P<0.01 vs. mutant. miR-520a-3p decreased SKA2 expression at both the mRNA (C) and protein (D) levels compared to MOCK in SGC-7901 cells. **P<0.01, ***P<0.001 vs. MOCK group. (E) SKA2 expression was analyzed in three GC cell lines (SGC-7901, BGC-823 and MGC-803) and a normal gastric epithelial cell line (GES-1). ***P<0.001 vs. GES-1. miR, microRNA; GC, gastric cancer; MOCK, mock transfected cells; NC, negative control; WT, wild-type; SKA2, spindle kinetochore-associated protein 2; UTR, untranslated region.