(A), real-time quantitative RT-PCR assay showing the miR-337-3p levels in normal gastric epithelial GES-1 cells and gastric cancer cell lines (AGS, SGC-7901, MKN-28, and MKN-45). (B and C), real-time quantitative RT-PCR assay indicating the miR-337-3p levels in gastric cancer cells transfected with empty vector (mock), miR-337-3p precursor, negative control inhibitor (anti-NC, 100 nmol/L), or anti-miR-337-3p inhibitor (100 nmol/L). (D and E), western blot and dual-luciferase assays showing the expression of MMP-14 and VEGF and promoter activity of MMP-14 in MKN-45 and SGC-7901 cells stably transfected with mock or miR-337-3p precursor. (F and G), western blot and dual-luciferase assays indicating the expression of MMP-14 and VEGF and promoter activity of MMP-14 in AGS and SGC-7901 cells transfected with anti-NC or anti-miR-337-3p inhibitor (100 nmol/L). (H and I), western blot and dual-luciferase assays showing the expression of AGO2 and MMP-14 and promoter activity of MMP-14 in MKN-45 and SGC-7901 cells stably transfected with mock or miR-337-3p precursor, and those co-transfected with scramble shRNA (sh-Scb) or AGO2 shRNA (sh-AGO2). (J) ChIP and qPCR assay indicating the binding of AGO2 to MMP-14 promoter in gastric cancer cells treated with RNase H or RNase A. (K) ChIP and qPCR assay showing the enrichment of AGO2, H3K9me2, H3K27me3, H3K4me3, and MZF1 on MMP-14 promoter in MKN-45 and SGC-7901 cells stably transfected with mock or miR-337-3p precursor, and those co-transfected with sh-Scb or sh-AGO2. *P < 0.01 vs. GES-1, mock, anti-NC, mock + sh-Scb, or IgG.