Purpose: Although microRNAs (miRNA) have been revealed as crucial modulators of tumorigenesis, our understanding of their roles in renal cell carcinoma (RCC) is limited. Here we sought to identify human miRNAs that act as key regulators of renal carcinogenesis.Experimental Design: We performed microarray-based miRNA profiling of clear cell RCC (ccRCC) and adjacent normal tissues and then explored the roles of miR-141 both in vitro and in vivo, which was the most significantly downregulated in ccRCC tissues.Results: A total of 74 miRNAs were dysregulated in ccRCC compared with normal tissues. miR-141 was remarkably downregulated in 92.6% (63/68) ccRCC tissues and would serve as a promising biomarker for discriminating ccRCC from normal tissues with an area under the receiver operating characteristics curve of 0.93. Overexpression of miR-141 robustly impaired ccRCC cell migratory and invasive properties and suppressed cell proliferation by arresting cells at G 0 -G 1 phase in vitro and in human RCC orthotopic xenografts. Significantly, the antitumor activities of miR-141 were mediated by its reversal regulation of erythropoietin-producing hepatocellular (Eph) A2 (EphA2), which then relayed a signaling transduction cascade to attenuate the functions of focal adhesion kinase (FAK), AKT, and MMP2/9.

miR-129-3p may act as a promising diagnostic biomarker for discriminating ccRCC from benign tumors and normal tissues and an independent prognostic biomarker in ccRCC. miR-129-3p may exert its anti-metastatic function through modulating multiple targets.

No abstract

microRNAs (miRNAs) play essential roles in several physiological and pathological processes, including tumor metastasis. Metastasis is associated with poor prognosis in renal carcinoma patients and almost 20-30% of patients present with distant metastasis at the time of diagnosis. The aim of the present study was to investigate the possible roles of miR-200c in regulating metastasis and to identify its target genes in renal cell carcinoma (RCC). Among the miRNAs downregulated in our tissue specimen microarray, miR-200c was downregulated significantly. Functional assays demonstrated that restoration of miR-200c significantly inhibited the migration and invasion of SN12-PM6 and 786-0 cells in vitro. Genome-wide gene expression analysis and TargetScan database studies showed that ZEB1, which has been shown to promote tumor invasion and migration through E-cadherin gene silencing, is a promising candidate target gene of miR‑200c. Overexpression of miR-200c in SN12-PM6 and 786-0 cells was concurrent with downregulation of ZEB1 and upregulation of E-cadherin mRNA and protein. In addition, miR-200c affected the protein expression of p-Akt and Akt. Thus, our study demonstrated that miR-200c decreases the metastatic ability of renal carcinoma cells by upregulating E-cadherin through ZEB1 and that modulating the expression of miR-200c could influence Akt protein levels. We therefore concluded that there is an Akt-miR-200c-E-cadherin axis in the epithelial-to-mesenchymal transition process in RCC.

Biomarkers to guide the clinical treatment of patients with renal cell carcinoma (RCC) are not yet routinely available. MicroRNAs (miRNAs) have been demonstrated to serve as biomarkers for a number of types of cancer. Based on a previous study by this group, we hypothesize that several highly differentially expressed miRNAs may serve as tissue and plasma biomarkers in patients with RCC. The expression levels of miR-210, miR-224 and miR-141 were analyzed in tissue samples from the same cohort of 78 patients with RCC, in paired pre- and post-operative plasma samples from 66 patients with clear cell RCC (ccRCC) and in 67 healthy controls by reverse transcription-quantitative polymerase chain reaction. Receiver operating characteristic (ROC) was used to evaluate the diagnostic accuracy associated with the expression of miR-210, miR-224 and miR-141. ROC curves revealed that the diagnostic accuracy (area under the curve) of tissue miR-210, miR-224, the ratio of miR-210/miR-141 (miR210/141), miR-224/miR-141 (miR224/141) and miR-210× miR-224/miR-141 (miR210×224/141) in ccRCC was 0.8329, 0.8511, 0.9412, 0.9898 and 0.9771, respectively. Notably, miR224/141 demonstrated the highest accuracy among these miRNAs for discriminating ccRCC tissues from normal tissues, with a sensitivity of 97.06% and a specificity of 98.53%. The expression levels of plasma miR-210 and miR-224 were significantly increased in patients compared with healthy control patients, and were reduced postoperatively (P<0.05). The diagnostic accuracy of plasma miR-210 and miR-224 were 0.6775 (89.55% sensitivity and 48.48% specificity) and 0.6056 (88.06% sensitivity and 40.91% specificity), respectively. The present study indicated that the tissue miR-224/miR-141 ratio is a potentially powerful tool for detecting ccRCC. However, plasma miR-210 and miR-224 may not be associated with diagnosis of ccRCC.

miRNA expression profiles are widely investigated in the major cancers, but their specific roles and functions in cancers have not yet to be fully elucidated. In this study, miRNA expression profiles were determined in clear cell renal cell carcinomas (ccRCC) and in matched normal kidney tissues by using a miRNA microarray platform which covers a total of 851 human miRNAs. Differential expression of 74 miRNAs were identified between ccRCC specimens and their matched adjacent noncancerous tissues, of which 30 were significantly upregulated in ccRCCs, and the other 44 were downregulated (fold change ! 2, P < 0.05). Interestingly, miR-200c was commonly downregulated in ccRCC specimens and ccRCC cell lines with significant functional consequences. Growth curve and FACS assay indicated that overexpression of miR-200c suppressed cell growth and induced cell-cycle arrest at G 0 -G 1 phases in SN12-PM6 and 786-O cells. Furthermore, miR-200c could suppress in vivo tumor growth of SN12-PM6 cells in mice. Bioinformatics exposed cyclin-dependent kinase 2 (CDK2) as a potential target of miR-200c, which was validated using a luciferase reporter assay. Mechanistic investigations revealed that miR-200c was directly responsible for suppressing the expression of CDK2 in ccRCC cell lines and xenografts. Taken together, miR-200c plays an antioncogenic role in ccRCC, through controlling cell growth and cell-cycle progression by downregulating the G 1 -S regulator CDK2.Implications: miR-200c exerts its novel antioncogenic function in renal cell carcinoma by controlling CDK2-dependent cell growth and cell-cycle progression.

TRAIL is a promising anticancer agent because it induces apoptosis in the majority of human cancer cells but spares the normal cells. To determine the mechanistic nature of how normal cells acquire a TRAIL-sensitive phenotype during the process of malignant transformation, an experimental cell system was developed by sequential introduction of human telomerase reverse transcriptase and SV40 T antigens (large and small) into normal human prostatic epithelial cells (PrEC). This model system demonstrated that inhibition of protein phosphatase 2A (PP2A), either by SV40 small T antigen, okadaic acid, Calyculin A, or PP2A catalytic subunit siRNA, sensitized normal human PrEC and immortalized cells to TRAIL-induced apoptosis. Moreover, sensitization occurred during the premalignant period of tumorigenesis and PP2A exerted its antiapoptotic activity by negatively regulating c-Fos/ AP-1. In addition, low-dose okadaic acid treatment sensitized TRAIL-resistant cancer cells to TRAIL, suggesting that PP2A inhibitors could be used as an enhancer of apoptosis induced by TRAIL or TRAIL-like agents. These data indicate that downregulation of PP2A activity is a critical step for normal cells to acquire a TRAIL-sensitive phenotype during tumorigenesis and that the level of PP2A activity may foretell cellular sensitivity to TRAILinduced apoptosis.

<p>PDF file - 58K, EphA2 protein is upregulated in clinical ccRCC tissues.</p>