Circ_0008532 promotes bladder cancer progression by regulation of the miR-155-5p/miR-330-5p/MTGR1 axis.

Circular RNAs (circRNAs) have been associated with bladder cancer (BC), but the specific underlying molecular mechanism of their association with BC development has not been fully explored. Levels of Circ_0008532, MTGR1 and miR-155-5p/miR-330-5p in bladder cancer cell lines and tissues were determined with quantitative real-time PCR and western blotting assays. In vitro and in vivo assays were performed to investigate the function of circ_0008532 in tumorigenesis in bladder cancer cells. The relationships of Circ_0008532, MTGR1 and miR-155-5p/miR-330-5p were predicted using bioinformatic tools and verified by RNA-FISH, RIP and luciferase assays. The effects of circ_0008532 on the Notch signaling pathway were determined by GSEA analysis and western blotting assay. We found that circ_0008532 is upregulated in BC cell lines and tissues. Moreover, overexpression of circ_0008532 promotes, and silencing of circ_0008532 inhibits the capacity for invasive in BC cells. In addition, circ_0008532 can directly interact with miR-155-5p and miR-330-5p as an miRNA sponge which mediates the expression of the miR-155-5p/miR-330-5p target gene MTGR1 and downstream Notch signaling. Circ_0008532 may act as an oncogene in BC through a novel circ_0008532/miR-155-5p, miR-330-5p /MTGR1/Notch pathway axis, which in turn may provide potential biomarkers and a therapeutic target for the management of bladder cancer.