Inhibitory Effects of MicroRNA-34a on Cell Migration and Invasion of Invasive Urothelial Bladder Carcinoma by Targeting Notch1

MicroRNAs (miRNAs or miRs) are a class of short, non-coding RNAs that participate in various oncological processes. This study aims to explore the roles of microRNA-34a (miR-34a) in invasive urothelial bladder carcinoma. miR-34a was transfected into bladder cancer cell lines 253J and J82. The miR-34a expression levels in tissues and cells were detected by using qRT-PCR. The Notch1 expression was detected by qRT-PCR and Western blotting. Cell migratory and invasive abilities were measured by Transwell chamber assay. Bioinformatics and luciferase assay were performed to predict and analyze the binding sites between miRNA-34a and Notch1. It was found that there was aberrant expression of miR-34a in bladder cancer tissues. Moreover, we revealed that ectopic expression of miR-34a suppressed cell migration and invasion, while forced expression of Notch1 increased cell migratory and invasive abilities. Finally, we observed that miR-34a transfection significantly down-regulated luciferase activity and reduced the mRNA and protein levels of Notch1. Our study concluded that microRNA-34a antagonizes Notch1 and inhibits cell migration and invasion of bladder cancer cells, which indicates the tumor-suppressive function of microRNA-34a in bladder cancer.