Circular RNA circ-VANGL1 as a competing endogenous RNA contributes to bladder cancer progression by regulating miR-605-3p/VANGL1 pathway

Increasing reports indicate that circular RNAs (circRNAs) are very important regulators in human diseases, including cancers. In bladder cancer (BC), several circRNAs have been reported to be involved in tumor progressions, such as circ-ITCH and circTCF25. However, the functions of most circRNAs in BC still remains largely unknown. In this study, we identified a novel circRNA termed as circ-VANGL1 by bioinformatics analysis. We found that circ-VANGL1 was highly expressed in BC tissues compared with adjacent normal tissues. Furthermore, we showed that circ-VANGL1 could serve as a prognostic marker for patients with BC. Through functional experiments, we found that circ-VANGL1 knockdown significantly suppressed BC cell proliferation, cell cycle, migration, and invasion in vitro. Besides, circ-VANGL1 silence inhibited BC cell propagation in vivo. Mechanistically, we identified circ-VANGL1 as a sponge of miR-605-3p which targeted VANGL1 in BC cells. Through repressing miR-605-3p availability, circ-VANGL1 contributes to VANGL1 expression, consequently leading to BC cell proliferation, migration, and invasion. Taken together, our study demonstrated circ-VANGL1/miR-605-3p/VANGL1 as a novel essential signaling pathway involved in BC progression.