MiR-194 regulates nasopharyngeal carcinoma progression by modulating MAP3K3 expression

Despite the recent development of treatment strategies for nasopharyngeal carcinoma, the effective management of this disease remains a challenging clinical problem. A better understanding of the regulatory roles of miR-194 and mitogen-activated protein kinase kinase kinase 3 (MAP3K3) in the nasopharyngeal-carcinoma-related gene network is required to address this issue. Here, we measured relative expression of miR-194 in human nasopharyngeal carcinoma tissues and normal epithelial tissues by quantitative real time PCR. We transfected cultured CNE-1 and C666-1 cells with miR-194 mimics, and then examined the effects on cell proliferation, cell migration and invasion. Luciferase reporter assay was used to validate the putative binding between miR-194 and MAP3K3. We then examined the effect of knockdown and overexpression of MAP3K3 on cell tumorigenesis. Expression of miR-194 is significantly down-regulated in nasopharyngeal carcinoma specimens and tumor cell lines when compared with normal controls. In addition, miR-194 suppressed tumor cell proliferation and viability, as well as migration and invasion of carcinoma cells. We found that miR-194 binds the 3' untranslated region of MAP3K3, and knockdown of miR-194 inhibited nasopharyngeal carcinoma cell proliferation, migration and invasion. In accordance, overexpression of MAP3K3 reversed the inhibitory effects of miR-194 in carcinoma cells. This study suggests that expression of miR-194 is down-regulated in nasopharyngeal carcinoma, and that miR-194 can directly target MAP3K3 to regulate tumor progression. Given the pivotal involvement of MAP3K3 in nasopharyngeal carcinoma development, targeting miR-194 may be a novel strategy for the treatment of nasopharyngeal carcinoma.