Figure 5. CircKIF4A promotes papillary thyroid cancer progression through circKIF4A-miR-1231-GPX4 axis. (A) Predicted interacting site of miR-1231 within the 3’-UTR of GPX4. (B) GPX4 expression in papillary thyroid cell lines. (C) Dual luciferase reporter assay of TPC-1 and KAT-5 cells. (D) Expression of GPX4 was reduced after overexpression of miR-1231. (E) Enrichment of circKIF4A, GPX4 and miR-1231 on AGO2 RNA binding protein assessed by RIP assay. (F) Overexpression of miR-1231 resulted in the reduction of GPX4 protein expression. (G) Knockdown of circKIF4A reduced the protein expression of GPX4.