Circ_0000514 promotes breast cancer progression by regulating the miR-296-5p/CXCL10 axis.

The biological function of circular RNA 0000514 (circ_0000514) in breast cancer (bc) is still unknown. In this study, we downloaded the microarray dataset GSE101123 from Gene Expression Omnibus database and then analysed the differentially expressed circular RNAs in bc tissues compared with adjacent tissues, and we demonstrated that circ_0000514 was up-regulated in bc tissues. Circ_0000514, miR-296-5p and CXC chemokine ligand10 (CXCL10) expressions in bc tissues and cell lines were probed by quantitativereal-time polymerase chain reaction and Western blot. Cell counting kit-8, 5-bromo-2'-deoxyuridine and transwell assays were adopted to determine the cell viability, proliferation, migration and invasion. The targeting relationship between miR-296-5p and circ_0000514 or CXCL10 3'-UTR was predicted by bioinformatics and validated by dual-luciferase reporter assay. We demonstrated that circ_0000514 and CXCL10 expressions were raised in bc tissues and cell lines while miR-296-5p expression was declined. Circ_0000514 knockdown could inhibit the proliferation, migration and invasion of bc cells and miR-296-5p overexpression also suppressed the malignant phenotypes of bc cells. Mechanistically, miR-296-5p was identified as the downstream target of circ_0000514 and could be inhibited by circ_0000514. Moreover, CXCL10 was the target of miR-296-5p, whose expression could be indirectly and positively regulated by circ_0000514. In conclusion, circ_0000514 is involved in bc progression via regulating miR-296-5p/CXCL10 axis. Graphical Abstract.