CircRNA.0007127 triggers apoptosis through the miR-513a-5p/CASP8 axis in K-562 cells.

: Circular RNAs (circRNAs) are covalently closed single-stranded RNAs with multiple biological functions. CircRNA.0007127 is derived from the carbon catabolite repression 4-negative on TATA-less () complex subunit 2 (), which was found to regulate tumor cell apoptosis through caspase pathway. : Potential circRNA.0007127 target microRNAs (miRNAs) were analyzed by miRanda, TargetScan, and RNAhybrid software, and the miRNAs with binding sites for apoptosis-related genes were screened. The roles of circRNA.0007127 and its downstream target, microRNA (miR)‍-513a-5p, were validated by quantitative real-time polymerase chain reaction (qPCR), flow cytometry, mitochondrial membrane potential, immunofluorescence, western blot, and caspase-8 (CASP8) protein activity in vitro in HO-induced K-562 cells. The circRNA.‍0007127‍‒‍miR-513a-5p and ‒‍miR-513a-5p interactions were verified by luciferase reporter assays. : Silencing circRNA.0007127 decreased cell apoptosis by inhibiting pathway activation in K-562 cells. Compared with the control group, the expression of was reduced by 50% and the 43-kD fragment of CASP8 protein was significantly reduced (≤0.05). The luciferase reporting assay showed that circRNA.0007127 combined with miR-513a-5p or , with extremely significant differences (≤0.001). The overexpression of miR-513a-5p inhibited the gene expression level of in a human myeloid leukemia cell model (75% change) and the level of a 43-kD fragment of CASP8 protein (≤0.01). The rescue experiment showed that cotransfection with circRNA.0007127 small-interfering RNA (siRNA) and the miR-513a-5p inhibitor increased gene expression and the apoptosis rate, suggesting that the miR-513a-5p inhibitor is a circRNA.0007127 siRNA antagonist. : CircRNA.0007127 regulates K-562 cell apoptosis through the miR-513a-5p/ axis, which can serve as a novel powerful molecular target for K-562 cells.