1. Department of Urology, Renmin Hospital of Wuhan University, Wuhan, Hubei Province, P.R.China.
2. Department of Urology, The Third Affiliated Hospital of Naval Medical University, Shanghai, P.R.China.
3. Department of Urology, The Affiliated Changzhou No. 2 People's Hospital of Nanjing Medical University, Changzhou 213000, Jiangsu Province, P.R.China.
*These authors contributed equally to this work.
Background: Bladder urothelial carcinoma (BC) is a common malignant tumor with a high incidence. This study aims to explore the role of miR-25 in BC tumorigenesis.
Material and Methods: The expression of miR-25 and PTEN were detected in clinical BC tissues. BC cell lines T24 and 5637 were used to transfect miR-25 mimics or inhibitors. Luciferase reporter gene detection confirmed the correlation between miR-25 and PTEN. CCK-8 method and flow cytometry were used to detect cell viability and apoptosis. Cell migration and invasion ability were examined by transwell assays. Western blotting detects the protein levels of PTEN, β-catenin, GSK-3β and p-GSK-3β.
Results: MiR-25 and PTEN expression are found to be negatively correlated in BC tissues. Further research confirmed that PTEN is a direct target of miR-25. In addition, the overexpression of miR-25 down-regulates the expression of PTEN, induces cell survival and inhibits apoptosis, while the knockout of miR-25 leads to the opposite result. miR-25 also inhibits the phosphorylation of GSK-3β and β-catenin without changing the total level of GSK-3β. In vivo experiments confirmed that miR-25 plays an oncogene's role by regulating the PTEN and Wnt/β-catenin signaling pathways.
Conclusion: Our research shows that miR-25 has a negative regulatory effect on the expression of PTEN in clinical specimens and in vitro. miR-25 can promote the proliferation of BC cells and induce cell invasion. Therefore, miR-25 may be used as a biomarker to predict the progression of BC.
Keywords: miR-25, PTEN, bladder cancer, tumorigenesis, prolifertation, metastasis