Effects of circ_0000218-siRNA on GC cells. AGS cells transfected with circ_0000218-siRNA, control-siRNA, circ_0000218-siRNA + inhibitor control or circ_0000218-siRNA + miR-139-3p inhibitor for 48 h. A AGS cell proliferation was determined using MTT assays. B and C AGS cell apoptosis was assessed via flow cytometry. D Cleaved-Caspase3 protein expression in AGS cells was detected via western blotting. E Ratio of cleaved-Caspase3/Caspase3. Data are presented as the mean ± SD. **P < 0.01 vs. control-siRNA; ##P < 0.01 vs. circ_0000218-siRNA + inhibitor control. circ, circular RNA; GC, gastric cancer; siRNA, small interfering RNA; miR, microRNA