Mounting evidence showed that microRNAs (miRNA) played an important role in nasopharyngeal carcinoma (NPC), the highest metastatic cancer among head and neck cancers which is widely prevalent in Southern China. Recently, miR-494 has been shown to be involved in the progression and prognosis of nasopharyngeal carcinoma. However, little is known about the function and mechanism of miR-494-3p, a mature miRNA of miR-494 in NPC. In the present study, we aimed to investigate the effects of miR-494-3p on the migration and invasion of NPC and further explore the underlying mechanisms.
The expression levels of miR-494-3p and SOX7 mRNA were examined in NPC specimens using quantitative reverse transcription-PCR (RT-qPCR). SOX7 was confirmed as a direct target of miR-494-3p through luciferase reporter assays, RT-qPCR, and western blotting. Furthermore, the roles of miR-494-3p and SOX7 on the proliferation, migration, invasion of NPC cells were analyzed by CCK-8 assay, wound healing assay and Boyden chamber assay respectively.
Our study demonstrated that miR-494-3p was commonly up-regulated in NPC specimens and NPC cell lines compared with non-tumor nasopharyngeal epithelial tissue or NP cells, and SOX7 mRNA levels were inversely correlated with miR-494-3p in clinical specimens. Moreover, SOX7 was negatively regulated at the post-transcriptional level by miR-494-3p via a binding site of SOX7-3′UTR. In addition, synthetic miR-494-3p mimics significantly promoted the proliferation, migration and invasion of S18 and S26 NPC cells, while synthetic miR-494-3p inhibitor resulted in decreased migration and invasion capabilities of these cells.
MiR-494-3p functions as a growth-promotive miRNA in NPC by directly targeting SOX7. Our results imply that miR-494-3p could serve as a potential diagnostic marker and therapeutic target for NPC.
Clinical trial identification
All authors have declared no conflicts of interest.