MiR-99a inhibits cell proliferation of nasopharyngeal carcinoma by targeting mTOR and serves as a prognostic factor

S.-H. Wu, L. Han, B.-C. Lu, H.-Y. Wang, C.-P. Zheng

Department of Radiation Oncology, the Second Clinical Medical College of Jinan University, Shenzhen People’s Hospital, Shenzhen, China. zhengclimb@tom.com

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• Oncology

OBJECTIVE: Nasopharyngeal carcinoma is the most common head and neck tumor in Southern China and Southeast Asia, presenting high rates of local invasion and early distant metastasis. Abnormally expressed miR-99a has been discovered in many tumors, and it is involved in nasopharyngeal carcinoma as well. This study aims to explore the molecular mechanisms of miR-99a and mTOR in regulating nasopharyngeal carcinoma.

PATIENTS AND METHODS: MiR-99a expression in nasopharyngeal carcinoma cells was detected by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay was performed for accessing cell proliferative capacity. Dual-Luciferase reporter gene assay was employed to verify the combination between miR-99a and mTOR.

RESULTS: We found that miR-99a was downregulated while mTOR was upregulated in nasopharyngeal carcinoma cell lines CNE1 and SUNE1. Low expression of miR-99a or high expression of mTOR predicted poor prognosis of nasopharyngeal carcinoma. MiR-99a overexpression inhibited the proliferation of CNE1 and SUNE1 cells through targeting mTOR.

CONCLUSIONS: We provided evidence that miR-99a inhibits NPC cell proliferative ability by inhibiting mTOR. The newly identified miR-99a/mTOR axis provides novel insight into the pathogenesis of NPC and represents a potential therapeutic target for NPC.

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