MiR-22 functions as a biomarker and regulates cell proliferation, cycle, apoptosis, migration and invasion in renal cell carcinoma.

It is well known that microRNAs (miRNAs) are associated with tumor occurrence and development, and the functions of microRNA-22 (miR-22) have been investigated in numerous kinds of cancer. However, the significance of miR-22 in renal cell carcinoma (RCC) has not been fully explored. In this study, we found that miR-22 was down-regulated both in serum and tissues of RCC patients by using real time quantitative PCR (RT-qPCR) analyses. In addition, miR-22 was negatively associated with hepatic metastatic sites and lymphatic metastasis, as well as the clinical stages and prognosis. Moreover, the expression of miR-22 could be increased though surgical treatment in serum of RCC patients. Functional studies were performed to investigate the role of miR-22 in the progression of RCC. Data suggested that overexpression of miR-22 inhibited cell proliferation, migration and invasion in Caki-1 cells, whereas blockage of miR-22 could reverse these oncogenic effects. We also identified erb-b2 receptor tyrosine kinase (ERBB3) was a novel target of miR-22 in RCC cells. Consequently, our work provides evidence that the down-regulation of miR-22 expression contributed to RCC. And miR-22 may be a potential molecule biomarker for diagnose and therapy evaluation in RCC. IJCEP