Up-regulation of the expressions of MiR-149-5p and MiR-99a-3p in exosome inhibits the progress of pituitary adenomas.

This study explored the function of microRNAs (miRNAs) in invasive pituitary adenomas (IPA), and developed a microRNA-exosome strategy for the disease treatment. Differentially expressed miRNAs and tumor-associated markers in IPA, non-invasive pituitary adenoma (NIPA), and rat pituitary adenoma cells were identified by bioinformatics analysis and qRT-PCR. Then, the cells were treated by miR-149-5p and miR-99a-3p mimics or inhibitors, or incubated with modified exosome with overexpressed or silenced miRNAs. The cell behaviors were analyzed by molecular experiments. Xenograft assays were constructed by injection of pituitary adenoma cells and exosome into NU/NU nude mice. Tumor size, weight, and expressions of markers related to miRNAs and angiogenesis were determined. Target genes for miR-99a-3p and miR-149 were predicted and verified by bioinformatics analysis and molecular experiments. Twenty differentially expressed miRNAs were identified, among which miR-99a-3p and miR-149 were inhibited in both pituitary adenoma cells and tissues significantly. Expressions of E-cadherin and p53 were down-regulated, while those of MMP-2, MMP-9, N-cadherin, Vimentin, and VEGF were up-regulated in pituitary adenoma cells and tissues, especially in IPA. Further experiments revealed that overexpressed miR-149 and miR-99a-3p inhibited the growth and metastasis of pituitary adenoma cells and tube formation of endothelial cells. MiR-149 and miR-99a-3p overexpressed by exosome showed similar suppressive effects on cell viability, metastasis, tube formation ability, in vivo tumor growth, and expressions of angiogenesis-related markers. Further analysis showed that NOVA1, DTL, and RAB27B were targeted by miR-99a-3p. This study found that overexpressed miR-149-5p and miR-99a-3p induced by exosome could suppress the progression of IPA. 1. MiR-149-5p and miR-99a-3p affect the expression of EMT- and ECM-related markers and tumor-related genes in rat pituitary adenoma cells treated with exosomes. 2. Exosome inhibited the tumor growth. 3. Overexpressed miR-149-5p and miR-99a-3p induced by exosome.