OBJECTIVE: The aim of this study was to investigate the function and potential mechanism of micro ribonucleic acid (miR)-146a-5p in oral squamous cell carcinoma (OSCC). MATERIALS AND METHODS: The expression of miR-146a-5p in OSCC tissues and cell lines was examined by quantitative Reverse Transcription-Polymerase Chain Reaction (qRT-PCR) analysis. Then, the role of miR-146a-5p in proliferation was analyzed by Cell Counting Kit-8 (CCK-8) assay. Besides, the proliferation and apoptosis of OSCC cells were detected by the colony formation assay and flow cytometry, respectively. Finally, the regulatory effect of miR-146a-5p/nuclear factor-kappa B subunit 1 (NF-κB1) was determined by Western blotting assay and Luciferase reporter assay system. RESULTS: The expression of miR-146a-5p was markedly upregulated in OSCC cell lines. In addition, the silence of miR-146a-5p inhibited the proliferation and promoted the apoptosis of OSCC cells. According to the results of the Western blotting analysis and Luciferase reporter gene assay, NF-κB1 was identified as a direct target of miR-146a-5p. Moreover, the downregulation of NF-κB1 restored the inhibitory effect of silenced miR-146a-5p on the proliferation of SCC-9 cells. CONCLUSIONS: MiR-146a-5p can inhibit the proliferation and accelerate the apoptosis of OSCC cells by directly targeting NF-κB1, and it plays a carcinogenic role in OSCC.

MicroRNA-31 (miR-31) has different expression patterns in various human cancers. Especially in urothelial carcinoma of the bladder, it has been demonstrated to be decreased expression in the invasive tumors and homozygously deleted. However, its clinical significance in human bladder cancer has not yet been elucidated. Thus, the purpose of this study was to investigate the diagnostic and prognostic values of miR-31 in this disease.