Circ_0061140 promotes metastasis of bladder cancer through adsorbing microRNA-1236

The purpose of this study was to investigate the expression characteristics of circular RNA circ_0061140 in bladder cancer (BCa), and to further explore its effects on invasiveness and migration capacity of BCa cells, as well as its possible potential mechanism.

Quantitative Real Time-Polymerase Chain Reaction (qRT-PCR) was performed to examine the expression level of circ_0061140 in tumor tissue samples and paracancerous ones collected from 42 patients with BCa, and the interplay between circ_0061140 level and the clinical indicators, as well as the prognosis of BCa patients were analyzed. Meanwhile, qRT-PCR was also used to verify circ_0061140 expression in BCa cell lines. In addition, a circ_0061140 knockdown model was constructed using Lentiviral in BCa cell lines, including T24 and 253j, and the effect of circ_0061140 on BCa cell functions and its underlying mechanisms were explored using Cell Counting Kit-8 (CCK-8), transwell, and cell wound healing assays.

qPCR results showed that the expression level of circ_0061140 in tumor tissues of BCa patients was remarkably higher than that in adjacent tissues, and the difference was statistically significant. Compared with patients with low expression of circ_0061140, patients with high expression of circ_0061140 had worse prognosis and higher incidence of lymph node or distant metastasis. Compared with those in the negative control group, the proliferation and invasion, as well as the metastasis ability of BCa cells in the sh-circ_0061140 group, were remarkably attenuated. In addition, bioinformatics and Luciferase reporter gene assay demonstrated that circ_0061140 can specifically bind to microRNA-1236. At the same time, the results of qPCR revealed that the expression levels of circ_0061140 and microRNA-1236 were negatively correlated in the tumor tissues of BCa patients. Finally, cell recovery experiment indicated that silencing microRNA-1236 reversed the impact of the knockdown of circ_0061140 on the ability of BCa cells to proliferate and invade, suggesting that the two may regulate each other.

Circ_0061140 level was found remarkably elevated in BCa tissues, as well as in cell lines, which was closely relevant to the incidence of lymph node or distant metastasis of BCa patients. In addition, circ_0061140 may enhance the proliferation rate and invasion ability of BCa cells through the modulation of microRNA-1236.