microRNA 21 Promotes the Proliferation and Metastasis of Oral Squamous Cell Carcinoma by Targeting RECK

We aimed to explore the effects of microRNA 21 (miR-21) downregulation on the expression of RECK and the proliferation and metastasis of oral squamous cell carcinoma (OSCC) cells. Sixty-five tumor tissue (TT) and corresponding paracancerous tissue (PT) specimens were excised from patients with OSCC. The mRNA levels of miR-21 and RECK in TTs and PTs were determined using qPCR. To assess the effects of miR-21-mediated modulation of RECK expression on tumor behavior, the OSCC cell line CAL-27 was transfected with miR-21 mimic, miR-21 inhibitor, or negative control (miR-NC). Compared with PTs, TTs showed increased levels of miR-21 and decreased mRNA and protein levels of RECK. Compared with CAL-27 cells transfected with miR-NC, those transfected with miR-21 inhibitor had upregulated RECK mRNA and protein expression, whereas those transfected with miR-21 mimic had downregulated RECK expression. After 48-72 h of transfection, the miR-21 mimic group exhibited higher cell proliferation rate than other groups. miR-21 was up-regulated and RECK expression was downregulated in OSCC. The downregulation of miR-21 upregulates RECK expres-sion via disinhibition, thereby suppressing the proliferation and migration and accelerating the apoptosis of OSCC cells. Thus, the downregulation of miR-21 may be an effective strategy against OSCC.