MicroRNA-30a as a prognostic factor in urothelial carcinoma of bladder inhibits cellular malignancy by antagonising Notch1

Objective To explore the relation between microRNA-30a (miR-30a) and Notch1, and to evaluate the potential prognostic role of miR-30a in invasive urothelial carcinoma of the bladder (UCB). Patients and methods In all, 50 invasive UCB tissue specimens, along with the adjacent bladder tissue specimens were obtained, and the clinical parameters of the 50 patients were analysed. Bioinformatics analysis was performed and miR-30a was selected as a potential miRNA targeting Notch1, with a luciferase assay performed to verify the binding site between miR-30a and Notch1. Quantitative real-time reverse transcriptase-polymerase chain reaction was used to assess the RNA expressions of miR-30a and Notch1, while Western Blotting and immunohistochemical staining were used to assess the protein expression of Notch1. Finally, cell proliferation, cell cycle, cell migration and invasion assays were used to evaluate the cellular effects of miR-30a and Notch1 on the UCB cell lines T24 and 5637. Results MiR-30a was downregulated in tumour tissues when compared with adjacent bladder tissues (P < 0.001), negatively correlating with Notch1 messenger RNA (R-2 0.106, P = 0.021) in invasive UCB, and miR-30a expression further decreased in patients with shorter overall survival and disease-free survival (P = 0.039 and P = 0.037, respectively). The luciferase assay showed that miR-30a inhibited the Notch1 30-untranslated region reporter activities in the T24 and 5637 cell lines (both P < 0.001). Both miR-30a and small interfering RNA Notch1 negatively regulated cell proliferation (P = 0.002 and P = 0.035 in T24; P = 0.029 and P = 0.037 in 5637 cell lines), activated cell cycle arrest (both P < 0.001 in T24; both P < 0.001 in 5637 cell lines), and prevented cellular migration (both P < 0.001 in T24; P = 0.003 and P < 0.001 in 5637 cell lines) and invasion (P = 0.009 and P = 0.006 in T24; P = 0.006 and P = 0.002 in 5637 cell lines) abilities. Ectopic Notch1 without the 3'untranslated region partially rescued the above-mentioned cellular effects of over-expressed miR-30a on T24 and 5637 cells. Conclusions MiR-30a lessens cellular malignancy by antagonising oncogene Notch1 and plays an effective prognostic role in invasive UCB.