The aim of the present study was to explore the functional role of miR-524 in oral squamous cell carcinoma (OSCC) and determine its underlying mechanism.
Tumor tissues and adjacent tissues were obtained from 55 patients with OSCC (20 females and 35 males) with a mean age of 54 years (range from 24 to 72 years). Additionally, OSCC cell lines culture was used and Reverse transcription‑quantitative PCR (RT-qPCR) was applied to measure the expression of miR-524 in OSCC tissues and cells. The protein density of Metadherin (MTDH) in OSCC tissues was detected by Immunohistochemistry (IHC) assay. MiR-524 mimic was employed to investigate the impact of miR-524 on proliferation, migration, and invasion using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay and transwell assays. The dual luciferase reporter assay was utilized to investigate the interaction between MTDH and miR-524 expression. Cells transfected with miR-524 mimic and pcDNA-MTDH were subjected to western blot to investigate the role of NF-κB signaling in miR-524/MTDH axis mediated cell proliferation, migration, and invasion.
MiR-524 expression was decreased significantly in OSCC tissues compared to adjacent tissues, and closely related to clinical stage, tumor size, and lymph node metastasis. Over-expression of miR-524 suppressed the proliferation, migration, and invasion of OSCC cells. Luciferase reporter assay results demonstrated that MTDH was the target gene of miR-524. Over-expression of miR-524 reduced MTDH expression and inhibited NF-κB signaling pathway. Rescue experiments revealed that over-expression of MTDH partially reversed the efficacy of miR-524 mimic on OSCC cells.
These results indicated that miR-524 inhibits the activation of NF-κB signaling pathway via inhibiting MTDH, resulting in the suppression of cell proliferation, migration, and invasion.

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