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Medical Science Monitor Basic Research


eISSN: 1643-3750

MiR-185-3p and miR-324-3p Predict Radiosensitivity of Nasopharyngeal Carcinoma and Modulate Cancer Cell Growth and Apoptosis by Targeting SMAD7

Jianhua Xu, Qin Ai, Hanhai Cao, Quan Liu

Department of Ear, Nose and Throat (ENT), People’s Hospital of Chengyang, Qingdao, Shandong, China (mainland)

Med Sci Monit 2015; 21:2828-2836

DOI: 10.12659/MSM.895660

Available online: 2015-09-21

Published: 2015-09-21


BACKGROUND: MiR-185-3p and miR-324-3p are 2 miRNAs that regulate nasopharyngeal carcinoma (NPC) radioresistance. This study tried to assess the clinical values of low miR-185-3p and low miR-324-3p expression in predicting response to radiotherapy (RT) and prognosis of NPC and to explore their new downstream targets.
MATERIAL AND METHODS: We recruited 80 patients with primary NPC. MiR-185-3p and miR-324-3p expression in the tumor tissues before and after RT or chemoradiotherapy (CRT) were determined. Overall survival and recurrence-free survival curves were estimated to assess the prognostic values of these 2 miRNAs. Their target was predicted using an online database and verified using dual luciferase assay, qRT-PCR, and Western blot analysis. In addition, the function of miR-185-3p/miR-324-3p-SMAD7 axis in NPC cells was investigated.
RESULTS: The expression of miR-185-3p and miR-324-3p was significantly reduced after RT in radioresistant but not in radiosensitive cases. Although miR-185-3p and miR-324-3p are not independent prognostic indicators of overall survival of NPC, their low expression is still associated with poor overall survival and recurrence-free survival. In addition, miR-185-3p and miR-324-3p can modulate growth and apoptosis of NPC cells, partly via SMAD7.
CONCLUSIONS: Combined low miR-185-3p and miR-324-3p might be important markers for prediction of low response to RT/CRT and poor overall survival and recurrence-free survival. MiR-185-3p and miR-324-3p can modulate NPC cell growth and apoptosis, at least partly through targeting SMAD7.

Keywords: Apoptosis - radiation effects, Adult, Cell Growth Processes - radiation effects, Gene Expression Regulation, Neoplastic, HEK293 Cells, MicroRNAs - genetics, Nasopharyngeal Neoplasms - radiotherapy, Prognosis, Radiation Tolerance - genetics, Smad7 Protein - genetics, Transfection