miR‐490‐5p suppresses tumour growth in renal cell carcinoma through targeting PIK3CA

BACKGROUND INFORMATION: Dysregulated micro-RNAs have been reported in many human cancers, including renal cell carcinoma. Recent studies indicated that miR-490 is involved in tumour development and progression. However, the expression profile and function in renal cell carcinoma remains unknown. RESULTS: Herein, we showed that miR-490-5p was down-regulated in renal cell carcinoma tissues and cells compared with the adjacent normal tissues and normal cells. We also provided evidence that miR-490-5p acts as a tumour suppressor in renal carcinoma in a variety of in vitro and in vivo assays. Mechanistically, miR-490-5p was verified to directly bind to 3' UTR of the PIK3CA mRNA and reduce the expression of PIK3CA at both mRNA and protein levels, which further inhibits phosphatidylinositol 3-kinase/Akt signalling pathway. We further showed that knockdown of PIK3CA can block the growth inhibitory effect of miR-490-5p, and over-expression of PIK3CA can reverse the inhibitory effect of miR-490-5p on renal cancer cell tumourigenicity. CONCLUSIONS: Taken together, our results indicated for the first time that miR-490-5p functions as a tumour suppressor in renal carcinoma by targeting PIK3CA. SIGNIFICANCE: Our findings suggest that miR-490-5p may be a potential gene therapy target for the treatment of renal cell carcinoma.