Figure 4. SLC7A11 acts as the target of miR-375/409-3P/515-5p and is inhibited via circEPSTI1 knockdown. (A) Schematic diagram of the predicted miR-375, miR-409-3P and miR-515-5p sites in the 3′UTR of SLC7A11 mRNA. (B) Luciferase assay of cancer cells cotransfected with miR-375, miR-409-3P and miR-515-5p mimics and a luciferase vector containing SLC7A11-3'UTR-wt or mutant constructs with mutated miR-375/409-3P/515-5p binding sites (SLC7A11-3'UTR-mut). (C) SLC7A11 expression after transfection with miR-375, miR-409-3p, miR-515-5p mimics and scrambled control detected by QRT-PCR analysis. (D) RIP assay revealed that the enrichment of circEPSTI1, SLC7A11 and miR-375, miR-409-3P and miR-515-5p on Ago2 relative IgG. (E) A RIP on Ago2 was conducted. *, P < 0.05; **, P < 0.01 compared to the negative control group.