MicroRNA-92b inhibits epithelial-mesenchymal transition-induced migration and invasion by targeting Smad3 in nasopharyngeal cancer

Increasing studies reports that aberrant miRNAs contribute to nasopharyngeal carcinoma (NPC) development and progression. However, the role of miR-92b in NPC remains unclear. In present research, we found that a reduced miR-92b expression in NPC tissues and cell lines. The clinical data showed that the down-regulated miR92b expression was obviously associated with adverse prognostic characteristic. Furthermore, we confirmed that miR-92b was a novel independent prognostic symbol for predicting 5-year survival of NPC patients. MiR-92b overexpression inhibited cell migration, invasion and EMT progress, while down-regulated miR-92b reversed the effect. Besides, miR-92b could modulate Smad3 by directly binding to its 3 '-UTR. In clinical samples of NPC, miR-92b inversely correlated with Smad3. Alternation of Smad3 expression at least partially abrogated the migration, invasion and EMT progress of miR-92b on NPC cells. In summary, our results indicated that miR-92b functioned as a tumor suppressor gene in regulating the EMT and metastasis of NPC via targeting Smad3, and may represent a novel potential therapeutic target and prognostic marker for NPC.