Purpose: To explore the mechanisms underlying clear-cell renal cell carcinoma (ccRCC) metastasis using transcriptional profiling and bioinformatics analysis of ccRCC samples, and to elucidate the role of FOXO3a in ccRCC metastasis.Experimental Design: Gene expression profiling was performed using four primary metastatic and five primary nonmetastatic ccRCC samples. The mRNA and protein levels of FOXO3a in ccRCC samples were investigated by real-time reverse transcription PCR and immunohistochemistry, respectively. The association between metastasis-free survival of patients with ccRCC and FOXO3a mRNA levels was analyzed. Biologic functions of FOXO3a in renal cancer cell lines were investigated. The influence of FOXO3a on tumor metastasis was also studied in vivo orthotopic xenograft tumor model. Finally, the mechanism by which FOXO3a attenuation could increase invasion and migration of tumor cells was explored.Results: Bioinformatics analysis of the profiling data identified FOXO3a as a key factor in ccRCC metastasis. FOXO3a expression was decreased in primary metastatic ccRCC samples. Patients with low FOXO3a mRNA levels had poor metastasis-free survival (P ¼ 0.003). Knocking down FOXO3a induced tumor cell invasion and migration in the nonmetastatic ccRCC cells. Induced FOXO3a overexpression in SN12-PM6 cells could inhibit tumor metastasis in vivo. Downregulation of FOXO3a increased SNAIL1 expression, thereby activating the epithelial-mesenchymal transition (EMT) of RCC cell lines.Conclusions: The loss of FOXO3a induced EMT of tumor cells by upregulating SNAIL1, which promoted tumor cells metastasis in vitro and in vivo. Thus, FOXO3a could be considered as an independent prognostic factor in ccRCC metastasis and could be a marker of occult metastases. Clin Cancer Res; 20(7); 1779-90. Ó2014 AACR.

Inflammation influences cancer development and progression, and a low lymphocyte to monocyte ratio (LMR) has been reported to be a poor prognostic indicator in several malignancies. Here we quantify the prognostic impact of this biomarker and assess its consistency in various cancers. Eligible studies were retrieved from PubMed, Embase and Web of Science databases. Overall survival (OS) was the primary outcome, cancer-specific survival (CSS), disease-free survival (DFS), recurrence-free survival (RFS), and progression-free survival (PFS) were secondary outcomes. Pooled hazard ratios (HRs), odds ratios (ORs), and 95% confidence intervals (CIs) were calculated. Fifty-six studies comprising 20,248 patients were included in the analysis. Overall, decreased LMR was significantly associated with shorter OS in non-hematological malignancy (HR: 0.59, 95% CI: 0.53–0.66; P < 0.001) and hematological malignancy (HR: 0.44, 95% CI: 0.34–0.56; P < 0.001). Similar results were found in CSS, DFS, RFS and PFS. Moreover, low LMR was significantly associated with some clinicopathological characteristics that are indicative of poor prognosis and disease aggressiveness. By these results, we conclude that a decreased LMR implied poor prognosis in patients with cancer and could serve as a readily available and inexpensive biomarker for clinical decision.

This is a systematic review of studies investigating the prognostic value of different microRNAs (miRs) in renal cell carcinoma (RCC). Twenty-seven relevant studies were identified, with a total of 2578 subjects. We found that elevated expression of miR-21, miR-1260b, miR-210, miR-100, miR-125b, miR-221, miR-630, and miR-497 was associated with a poor prognosis in RCC patients. Conversely, decreased expression of miR-106b, miR-99a, miR-1826, miR-215, miR-217, miR-187, miR-129–3p, miR-23b, miR-27b, and miR-126 was associated with a worse prognosis. We performed meta-analyses on studies to address the prognostic value of miR-21, miR-126, miR-210, and miR-221. This revealed that elevated miR-21 expression was associated with shorter overall survival (OS; hazard ratio [HR], 2.29; 95% confidence interval [CI], 1.28–4.08), cancer specific survival (CSS; HR, 4.16; 95% CI, 2.49–6.95), and disease free survival (DFS; HR, 2.15; 95% CI, 1.16–3.98). The decreased expression of miR-126 was associated with shorter CSS (HR, 0.35; 95% CI, 0.15–0.85), OS (HR, 0.45; 95% CI, 0.30–0.69), and DFS (HR 0.30; 95% CI, 0.18–0.50). Our comprehensive systematic review reveals that miRs, especially miR-21 and miR-126, could be promising prognostic markers and useful therapeutic targets in RCC.

No abstract

BackgroundTranscription factor E2F1 exerts effects on many types of cancers. As an upstream regulator of a host of genes, E2F1 can trigger diverse aberrant transcription processes that may dominate malignancy. Clear cell renal cell carcinoma (ccRCC) is the most common subtype in renal cell carcinoma which displays high malignancy and has a shortage of biomarkers in clinics. Our study aimed to explore the function of E2F1 in ccRCC and its correlation with clinicopathological parameters.Methodology/Principle FindingsTranscription factor E2F1 was mainly distributed in cancer cell nucleus and mRNA expression significantly increased in 72 cases of clear cell renal cell carcinoma (ccRCC) tissues compared with adjacent non-cancerous kidney tissues (p<0.001). The protein expression was consistent with mRNA expression. Further analysis in 92 cases indicated that E2F1 mRNA level expression was associated with the tumor pathologic parameters embracing diameter, Fuhrman tumor grade, pT stage, TNM stage grouping and macrovascular infiltration (MAVI). These surgical specimens had high grade tumors accompanied with an elevated E2F1 expression. Moreover, E2F1 transfection was found to contribute significantly to cancer cell proliferation, migration and invasion in vitro.Conclusions/SignificanceOverexpression of E2F1 may be a key event in the local and vascular infiltration of ccRCC indicated by the activation of matrix metalloproteinase (MMP) 2 and MMP9. These findings highlighted the implication of E2F1’s function in the metastatic process. Furthermore, the clinical relevance of E2F1 in ccRCC pointed to a potential new therapeutic target.

The transcription factor KLF6 has an essential role in the development and metastasis of multiple human cancers. Paradoxically, KLF6 expression was found to be attenuated in primary metastatic clear cell renal cell carcinoma (ccRCC), such that it is unclear how KLF6 affects malignant progression in this setting. In this study, we demonstrate that KLF6 attenuation in renal cells is sufficient to promote E2F1-mediated epithelialmesenchymal transition and metastatic prowess. In a mouse xenograft model of human ccRCC, silencing KLF6 increased tumor cell proliferation and malignant character, whereas E2F1 silencing reversed these properties. These effects were corroborated in a metastatic model system, where we observed a greater number of pulmonary metastatic lesions formed by ccRCC cells where KLF6 was silenced and E2F1 enforced. Analysis of clinical specimens of ccRCC revealed that low levels of KLF6 and high levels of E2F1 correlated closely with ccRCC development. Overall, our results established the significance of activating the KLF6-E2F1 axis in aggressive ccRCC, defining a novel critical signaling mechanism that drives human ccRCC invasion and metastasis. Cancer Res; 77(2); 330-42. Ó2016 AACR.

MicroRNAs (miRNAs) have emerged as critical modulators of carcinogenesis and tumor progression. In the present work, we sought to identify the biological function of miR-155 as well as its underlying mechanism in clear cell renal cell carcinoma (ccRCC). We examined the expression of miR-155 in clear cell RCC (ccRCC) and adjacent normal tissues and then explored the roles of miR-155 both in vitro and in vivo. The results of this analysis indicated that miR-155 activity was significantly upregulated in ccRCC tissues compared with the corresponding normal tissues. miR-155 was associated with ccRCC aggressiveness in both cell lines and clinical specimens, and a specific and inverse correlation between miR-155 and E2F2 expression was found in human ccRCC samples. Overexpression of miR-155 in 786-O cells decreased E2F2 expression while reduction of miR-155 by anti-miR-155 in ACHN cells elevated E2F2 expression. Re-expression of E2F2 in 786-O cells repressed the cell migration/invasion abilities elevated by miR-155, whereas knockdown of E2F2 in ACHN cells restored these cellular functions hampered by the miR-155 inhibitor. Using Western blot and luciferase reporter assays, we determined that E2F2 was a direct target of miR-155. Taken together, the in vitro and in vivo results demonstrate that miR-155 functions as a tumor-promoting miRNA by targeting E2F2 in ccRCC.

Clear cell renal cell carcinoma (ccRCC) is a gender-biased tumor. Here we report that there is also a gender difference between pulmonary metastasis and lymph node metastasis showing that the androgen receptor (AR)-positive ccRCC may prefer to metastasize to lung rather than to lymph nodes. A higher AR expression increases ccRCC hematogenous metastasis yet decreases ccRCC lymphatic metastases. Mechanism dissection indicates that AR enhances miR-185-5p expression via binding to the androgen response elements located on the promoter of miR-185-5p, which suppresses VEGF-C expression via binding to its 3′ UTR. In contrast, AR-enhanced miR-185-5p also promotes HIF2α/VEGF-A expression via binding to the promoter region of HIF2α. Together, these results provide a unique mechanism by which AR can either increase or decrease ccRCC metastasis at different sites and may help us to develop combined therapies using anti-AR and anti-VEGF-C compounds to better suppress ccRCC progression.