Figure 3. circFGFR3 as a ceRNA sponge of miR-29a-3p in OC cells. (A) A schematic drawing presenting the putative binding sequence of circFGFR3 and miR-29a-3p; (B) A schematic drawing showing the putative binding sequence of miR-29a-3p and the E2F1 3’UTR; (C and D) Plasmids encoding wild-type and mutated circFGFR3 or E2F1 3’-UTR were transfected into SKOV3 cells with or without miR-29a-3p mimics. Luciferase activity was detected 48 h after transfection. (E) circFGFR3 and E2F1 expression changes on the basis of enhanced miR-29a-3p were detected in OC cells by using qRT-PCR. (F) circFGFR3 and E2F1 expression changes on the basis of circFGFR3 shRNA expression were detected in OC cells by using qRT-PCR. **P<0.01; ***P<0.05; (G) circFGFR3 overexpression increased E2F1 expression in OC cells; (H and I) circFGFR3 knockdown in OC cells with high levels of circFGFR3 decreased E2F1 expression; (J) Representative immunohistochemistry images showing a positive correlation between circFGFR3 and E2F1 in OC tissues, bar=100 μm; (K) Diagram showing a negative correlation between miR-29a-3p and circFGFR3 in OC tissues. A positive correlation between circFGFR3 and E2F1 was observed in OC tissues.