Objective: To investigate the role of circular RNA hsa_circ_0091017 in the progression of bladder cancer (BCa) and its possible molecular mechanisms.
Patients and methods: Quantitative Real Time-Polymerase Chain Reaction (qRT-PCR) was used to detect the expression level of circular RNA hsa_circ_0091017 in 40 pairs of BCa tissues and normal adjacent tissues, as well as in BCa cell lines. MiRNAs that could bind to the circular RNA hsa_circ_0091017 were predicted by bioinformatics databases and their expression levels were verified in BCa tissues and cell lines. The circular RNA hsa_circ_0091017 overexpression plasmid and the corresponding negative control were transfected into T24 and UMUC-3 cells, and their effects on cell proliferative ability, migration, and invasiveness were determined by cell counting kit-8 (CCK-8), 5-Ethynyl-2'- deoxyuridine (EdU), and transwell assays. In addition, the Dual-Luciferase reporter gene assay was used to verify the binding relation between the circular RNA hsa_circ_0091017 and microRNA-589-5p. Furthermore, in vitro reversal experiments were used to confirm the biological role of microRNA-589-5p in the progression of BCa mediated by circular RNA hsa_circ_0091017.
Results: QRT-PCR results revealed that the expression level of hsa_circ_0091017 was remarkably down-regulated in BCa tissues and cell lines, while the expression level of microRNA-589-5p was remarkably increased in BCa tissues and cells. Overexpression of the circular RNA hsa_circ_0091017 in BCa cells can inhibit the proliferation, migration, and invasiveness of BCa cells. At the same time, it was found that overexpression of the circular RNA hsa_circ_0091017 in BCa cells can inhibit the expression of microRNA-589-5p and there was a binding relation between the two in BCa cells. In addition, overexpression of microRNA-589-5p reversed the inhibitory effect of the circular RNA hsa_circ_0091017 on the malignant phenotype of BCa cells.
Conclusions: The circular RNA hsa_circ_0091017 can inhibit the proliferation, migration and invasiveness of BCa cells by regulating the expression of microRNA-589-5p.