miR-19a correlates with poor prognosis of clear cell renal cell carcinoma patients via promoting cell proliferation and suppressing PTEN/SMAD4 expression

MicroRNAs (miRNAs) were reported to be involved in the development of clear cell renal cell carcinoma (ccRCC). However, the study on miRNAs in ccRCC is far from complete. The present study identified miRNAs which could act as potential novel prognostic markers for ccRCC, and analyzed its possible mechanism. We found that miR-19a correlated with poor prognosis of ccRCC patients via promoting cell proliferation and suppressing PTEN/SMAD4 expression. Both the microarray screening result and TCGA KIRC dataset analysis showed that miR-19a was significantly upregulated in ccRCC tissues, and further analysis of TCGA data revealed that the upregulated level of miR-19a was strongly associated with advanced T stage and poor prognosis of ccRCC patients. Consistent with clinical observations, miR-19a overexpression significantly promoted ccRCC cell proliferation in vitro. To further explore the mechanism by which miR-19a correlated with cell proliferation and poor prognosis of ccRCC, we performed gene set enrichment analysis (GSEA) for target genes of miR-19a in ccRCC patients. Result indicated that the key target genes of miR-19a included SMAD4 and PTEN. In ccRCC tissues, expression levels of SMAD4 and PTEN were negatively correlated with expression level of miR-19a, revealing that miR-19a suppressed the expression of SMAD4 and PTEN in ccRCC patients. miR-19a overexpression significantly suppressed the expression of SMAD4 and PTEN in vitro, further verifying that SMAD4 and PTEN were the target genes of miR-19a in ccRCC cells. Our results elucidated the tumor promoting role of miR-19a and established miR-19a as a potential novel prognostic marker for ccRCC.