MicroRNA-524-5p Functions as a Tumor Suppressor in a Human Pituitary Tumor-Derived Cell Line

Clinical nonfunctional pituitary adenomas (NFAs) account for about 40 % of pituitary adenomas with almost no clinically relevant hormonal symptoms. Increasing evidence shows that many microRNAs are involved in the development and progression of pituitary adenomas. MicroRNA-524-5p (miR-524-5p) has been reported to cause characteristic alterations in various tumors. However, the functional importance of miR-524-5p in NFAs remains unknown. The aim of this study was to explore the effects of overexpressing miR-524-5p on the proliferation, migration, invasion, and tumorigenicity of pituitary-derived folliculostellate (PDFS) cells using lentiviral transfection. Interestingly, the results showed that overexpressing miR-524-5p downregulated pituitary tumor-transforming gene 1 (PTTG1) binding factor (PBF) expression at both mRNA and protein levels and significantly attenuated cell proliferation, clonogenicity, migration, and invasion in vitro. Moreover, enhancing miR524- 5p blocked tumor growth in a nude mouse xenograft model in vivo. These findings suggest that miR-524-5p appears to play a critical role in the regulation of biological properties of PDFS cells, and may represent a potential therapeutic target for NFAs.