Circular RNA nuclear receptor‐interacting protein 1 (circNRIP1) acts as a competing endogenous RNA and regulates pyruvate kinase M2 (PKM2) expression by binding microRNA (miR)‐541‐5p and miR‐3064‐5p. (A,B) Predicted (A) miR‐541‐5p and (B) miR‐3064‐5p binding sites in circNRIP1 (circNRIP1‐WT) and designed mutant sequences (circNRIP1‐Mut1, circNRIP1‐Mut2). TPC1 and BCPAP cells were transfected with circNRIP1‐WT, circNRIP1‐Mut1, circNRIP1‐Mut2, and indicated miRNAs, after which the luciferase reporter assay was carried out. (C,D) Predicted (C) miR‐541‐5p and (D) miR‐3064‐5p binding sites in PKM2 3′‐UTR (PKM2 3′‐UTR‐WT) and designed mutant sequences (PKM2 3′‐UTR‐Mut1, PKM2 3′‐UTR‐Mut2). TPC1 and BCPAP cells were transfected with PKM2 3′‐UTR‐WT, PKM2 3′‐UTR‐Mut1, PKM2 3′‐UTR‐Mut2, and the indicated miRNAs, after which the luciferase reporter assay was carried out. (E,F) Luciferase reporter assay of (E) TPC1 and (F) BCPAP cells cotransfected with PKM2 3′‐UTR‐WT, pcDNA3.1, circNRIP1‐WT, and circNRIP1‐Mut1 vectors. *p < 0.05