Down-regulation of miR-497 is associated with poor prognosis in renal cancer.

INTRODUCTION Clear cell renal cell carcinoma (ccRCC) is the most common type of cancer in the adult kidney, and the prognosis of metastatic ccRCC remains poor with high mortality. Recent study indicated that microRNAs (miRNAs) played critical roles in tumor progression. The aim of this study was to investigate the expression, biological role and clinical significance of miR-497 in ccRCC. METHODS Quantitative real-time PCR (qRT-PCR) was performed to detect the expression of miR-497 in renal cancer cell lines and ccRCC tissues. The association between miR-497 expression and overall survival was estimated by the Kaplan-Meier method. Gain of function assays were performed in the 786-O renal cancer cell line. RESULTS Expression of the miR-497 was significantly decreased in renal cancer cell lines and ccRCC tissues when compared with normal human proximal tubule epithelial cells and adjacent non-tumor tissues. Decreased miR-497 expression was significantly associated with tumor stage, histological grade and lymph node metastases. Significantly shorter overall survival was observed in patients with lower expression of the miR-497. Overexpression of miR-497 significantly inhibited renal cancer cell proliferation, migration and invasion. CONCLUSIONS Our results demonstrated that miR-497 was decreased in ccRCC tissues and may provide a potential prognostic biomarker and a potential target for therapeutic intervention.