Background: 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.
Keywords: lung adenocarcinoma; mTOR; microRNA-99a; prognosis; qRT-PCR.
Copyright © 2013 Wiley Periodicals, Inc.