The purpose of this study was to investigate the clinical significance of microRNA-99a expression in lung adenocarcinoma.Methods
qRT-PCR assay was performed to detect miR-99a expression in lung adenocarcinoma cells or tissues. The correlations of miR-99a expression with clinicopathological factors and prognosis of lung adenocarcinoma patients were analyzed. The effects of miR-99a expression on growth and apoptosis of lung adenocarcinoma cell line and its potential target gene were determined by MTT, flow cytometry, luciferase reporter, and Western blot assays.Results
The relative miR-99a expression in lung adenocarcinoma cells was significantly lower than that in normal lung bronchial epithelium cell line. Also, miR-99a expression in lung adenocarcinoma tissues was significantly lower than that in corresponding nontumor tissues. Low miR-99a expression was found to be closely correlated with advanced clinical stage and lymph node metastasis. Kaplan–Meier survival and Cox regression analyses showed that the status of miR-99a expression was an independent prognosis factor for lung adenocarcinoma patients. Functional analyses showed that upregulation of miR-99a could inhibit growth and induce apoptosis in lung adenocarcinoma cells by targeting mTOR.Conclusion
Low MiR-99a expression was a poor prognostic factor for patients with lung adenocarcinoma, and miR-99a functions as a tumor suppressor by targeting mTOR. J. Surg. Oncol. 2013 108:248–255. © 2013 Wiley Periodicals, Inc.