Figure 5. circIQCH promotes breast cancer progression via circIQCH-miR-145-DNMT3A axis. (A) Predicted binding sites of miR-145 within the 3’-UTR of DNMT3A mRNA according to TargetScan. (B) The relative expression level of DNMT3A in breast cancer cell lines. (C) Luciferase reporter assay of SKBR3 and BT474 cells co-transfected with miR-145 mimics and the 3’-UTR of DNMT3A wild type or mutant luciferase reporter. The putative miRNA binding site of 3’-UTR of DNMT3A was mutated. (D) Expression of DNMT3A was decreased after transfection with miR-145 mimics. Expression of DNMT3A was increased after transfection with miR-145 inhibitors. (E) Enrichment of circIQCH, DNMT3A and miR-145 on Ago2 assessed by RIP assay. (F) Enrichment of Ago2 to circIQCH was decreased while DNMT3A was increased after knockdown of circIQCH. (G) Knockdown of circIQCH resulted in the reduction of DNMT3A expression which was reversed by miR-145 inhibitors. PTEN and BRCA1 was upregulated after silencing circIQCH. (H) Cell proliferation rate was detected by CCK-8 assay after exogenously expressing DNMT3A or inhibiting miR-145 in circIQCH silencing SKBR3 and BT474 cells. (I) Cell migration ability was validated by transwell assay after exogenously expressing DNMT3A or inhibiting miR-145 in circIQCH silencing SKBR3 cells. *P<0.05; **P<0.01.