(A) Schematic representation of shRNA1 and sh-NC designed to target circFGD4 at the back-splice junctions. (B) Relative expression of circFGD4 was detected by qRT-PCR in AGS and BGC823 cells transfected with shRNA1 targeting circFGD4. (C and D) Cell proliferation abilities were detected by CCK-8 and colony formation assays after the transfection of shRNA1 or sh-NC in AGS and BGC823 cells. (E) DNA synthesis was observed by EdU assays after the transfection of shRNA1 or sh-NC in AGS and BGC823 cells. (F) Cell migration abilities were determined by transwell assays after the transfection of shRNA1 or sh-NC in AGS and BGC823 cells. (G) Cell migration capacities were detected by wound healing assays after the transfection of shRNA1 or sh-NC in AGS and BGC823 cells. (H) Representative images of the expression levels of E-cadherin (red) and vimentin (green) in AGS cells were assessed by IF after transfection. Nuclei were counterstained with DAPI (blue) (values are shown as the mean ± standard error of the mean based on three independent experiments; *P<0.05, **P<0.01).