The Effect And Mechanism Of MiR-519d On Oral Squamous Cell Carcinoma Invasion And Metastasis

Background & Purpose: miR-519d has been reported to play significant roles in the development and progression of multiple cancers.However,the expression level,biological function,and the potential regulatory mechanism in oral squamous cell carcinoma(OSCC)remain unclear.This study aimed to investigate the roles of miR-519d in OSCC and its underlying molecular mechanism,providing evidences and assistance for the diagnosis and therapy in OSCC.Methods: Quantitative real-time PCR was applied to detect the expression level of miR-519d in OSCC and matched normal tissues;Methylation-specific PCR was implemented to explore the effect of DNA methylation on miR-519d expression in OSCC;MTT proliferation experiment,Transwell migration and invasion assay,and would healing assay were conducted to investigate the influence of miR-519d on the biological phenotypes of OSCC cells;Bioinformatics methods,western blot,and luciferase reporter assay were performed to predict and validate the target gene of miR-519d in OSCC;Western blot and immunofluorescence assay were utilized to analyze the effect of miR-519 on the epithelial-mesenchymal transition in OSCC cells.Results: miR-519d was significantly downregulated in OSCC and the expression level of miR-519d was closely associated with lymph node metastasis,TNM stage,and the poor prognosis in OSCC patients;Further investigation suggested the hypermethylation in the promoter region may account for the repression of miR-519d in OSCC;In vitro experiments demonstrated miR-519d could remarkably inhibit the migration,invasion,and the epithelial-mesenchymal transition of OSCC cells and the regulatory functions of miR-519d were attained through targeting MMP3;Moreover,MMP3 was upregulated in OSCC and negatively correlated with miR-519 d.The expression level of MMP3 was significantly related with lymph node metastasis,TNM stage,and poor prognosis in OSCC patients.Conclusions: miR-519d could regulate the migration and invasion of OSCC cells through targeting MMP3 and this result provided evidences and assistance for the diagnosis and therapy for OSCC.