ccRCC Tumor Samples Research Articles

MicroRNA Expression Profiling in Clear Cell Renal Cell Carcinoma: Identification and Functional Validation of Key miRNAs.

ObjectiveThis study aims to profile dysregulated microRNA (miRNA) expression in clear cell renal cell carcinoma (ccRCC) and to identify key regulatory miRNAs in ccRCC.Methods and ResultsmiRNA expression profiles in nine pairs of ccRCC tumor samples at three different stages and the adjacent, non-tumorous tissues were investigated using miRNA arrays. Eleven miRNAs were identified to be commonly dysregulated, including three up-regulated (miR-487a, miR-491-3p and miR-452) and eight down-regulated (miR-125b, miR-142-3p, miR-199a-5p, miR-22, miR-299-3p, miR-29a, miR-429, and miR-532-5p) in tumor tissues as compared with adjacent normal tissues. The 11 miRNAs and their predicted target genes were analyzed by Gene Ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis, and three key miRNAs (miR-199a-5p, miR-22 and miR-429) were identified by microRNA-gene network analysis. Dysregulation of the three key miRNAs were further validated in another cohort of 15 ccRCC samples, and the human kidney carcinoma cell line 786-O, as compared with five normal kidney samples. Further investigation showed that over-expression of miR-199a-5p significantly inhibited the invasion ability of 786-O cells. Luciferase reporter assays indicated that miR-199a-5p regulated expression of TGFBR1 and JunB by directly interacting with their 3’ untranslated regions. Transfection of miR-199a-5p successfully suppressed expression of TGFBR1 and JunB in the human embryonic kidney 293T cells, further confirming the direct regulation of miR-199a-5p on these two genes.ConclusionsThis study identified 11 commonly dysregulated miRNAs in ccRCC, three of which (miR-199a-5p, miR-22 and miR-429) may represent key miRNAs involved in the pathogenesis of ccRCC. Further studies suggested that miR-199a-5p plays an important role in inhibition of cell invasion of ccRCC cells by suppressing expression of TGFBR1 and JunB.

Metabolomic profile of glycolysis and the pentose phosphate pathway identifies the central role of glucose-6-phosphate dehydrogenase in clear cell-renal cell carcinoma.

The analysis of cancer metabolome has shown that proliferating tumor cells require a large quantities of different nutrients in order to support their high rate of proliferation. In this study we analyzed the metabolic profile of glycolysis and the pentose phosphate pathway (PPP) in human clear cell-renal cell carcinoma (ccRCC) and evaluate the role of these pathways in sustaining cell proliferation, maintenance of NADPH levels, and production of reactive oxygen species (ROS). Metabolomic analysis showed a clear signature of increased glucose uptake and utilization in ccRCC tumor samples. Elevated levels of glucose-6-phosphate dehydrogenase (G6PDH) in association with higher levels of PPP-derived metabolites, suggested a prominent role of this pathway in RCC-associated metabolic alterations. G6PDH inhibition, caused a significant decrease in cancer cell survival, a decrease in NADPH levels, and an increased production of ROS, suggesting that the PPP plays an important role in the regulation of ccRCC redox homeostasis. Patients with high levels of glycolytic enzymes had reduced progression-free and cancer-specific survivals as compared to subjects with low levels. Our data suggest that oncogenic signaling pathways may promote ccRCC through rerouting the sugar metabolism. Blocking the flux through this pathway may serve as a novel therapeutic target.

Prognostic implication of TIM-3 in clear cell renal cell carcinoma

Clear cell renal carcinoma (ccRCC) is the most common tumor of the kidney.in adults. The prognosis of ccRCC remains unsatisfactory. Recently, T cell immunoglobulin mucin-3 (TIM-3), a novel transmembrane protein, has been implicated in tumor biology. Its role in ccRCC remains unknown. The aim of this study was to investigate the roles of TIM-3 as a prognostic marker in patients with ccRCC.TIM-3 protein expression was determined by immunohistochemistry and Western blot from 137 ccRCC tumor samples and adjacent normal renal tissues. We performed also the cell proliferation assay using 3-(4,5-dimethylthiazol -2yl)-2,5-diphenyl-2H tetrazolium bromide (MTT) and cell invasion assay. The effects of small interfering RNA (siRNA)-mediated knockdown of TIM-3 (TIM-3 siRNA) in two human ccRCC cell lines were evaluated. TIM-3 expression was higher in ccRCC tissue than in the adjacent normal renal tissue (P<0.001). High TIM-3 expression was an independent predictor of both cancer-specific survival and progression-free survival. TIM-3 protein was expressed in both ccRCC cell lines. Knockdown of TIM-3 suppressed the proliferation and invasion capacity of ccRCC cell lines.TIM-3 expression was associated with poor prognosis in ccRCC. Taken together, TIM-3 is a potential prognostic marker in ccRCC.

Highlights from Recent Cancer Literature

Highlights from Recent Cancer Literature

Abstract B29: Role of inflammatory-related gene expression in clear cell renal cell carcinoma

Abstract Renal cell carcinoma (RCC) is the 10th most common cancer in United States with clear-cell renal carcinoma (ccRCC) being the most common. Many genes and signaling pathways have been implicated in ccRCC development, including the inflammation pathway. However, less is known about how gene expression variation within this pathway influences ccRCC development and clinical outcomes. Gene expression in tumor and adjacent normal tissues from 93 patients with ccRCC was detected using a genome-wide expression array and a panel of 661 inflammation-related genes was then analyzed. Differential expression patterns between tumor and adjacent normal tissue were observed. Association between expression and recurrence or survival was evaluated with those genes showing significant association further tested in a validation set of 258 ccRCC tumor samples. A total of 151 genes with at least a 2-fold change in gene expression between adjacent normal and tumor were identified, with a majority of the genes being upregulated in the tumors. Eleven inflammation-related genes (BLNK, APP, IL8, CARD9, SOD2, IL10RA, GADD45G, ADORA3, CXCL1, CIITA, and NCF2) were found to be significantly associated with recurrence and/or overall survival in 93 ccRCC tumors and selected for further validation. Expression of CIITA and NCF2 was significantly associated with overall survival in the replication dataset with high expression levels associated with significant 2.65-fold (95% CI=1.28-5.49, P=0.0088) and a 2.26-fold (95% CI=1.12-4.58, P=0.023) increased risk of dying, respectively. Our results suggest expression of CIITA and NCF2 genes may be significant prognostic biomarkers for risk of dying in patients with ccRCC. Citation Information: Cancer Prev Res 2010;3(12 Suppl):B29.

RKTG inhibits angiogenesis by suppressing MAPK-mediated autocrine VEGF signaling and is downregulated in clear-cell renal cell carcinoma

Vascular endothelial growth factors (VEGFs) are crucial regulators of angiogenesis and vasculogenesis. The autocrine VEGF signaling is required for maintaining the homeostasis of vasculature. Dysregulation of angiogenesis is implicated in the development of many human cancers, especially in clear-cell renal cell carcinoma (ccRCC), a highly vascularized tumor. Meanwhile, antiangiogenesis has become a mainstay in the treatment of human cancers. In this study, we analyzed the functional roles of RKTG (Raf Kinase Trapping to Golgi), a negative regulator of mitogen-activated protein kinase (Raf/MEK/ERK) signaling, by sequestration of Raf kinase to the Golgi apparatus, in angiogenesis and ccRCC. Through a series of in vitro and in vivo experiments, we found that RKTG has a negative effect on cell proliferation, migration, sprouting and angiogenesis of endothelial cells. RKTG, by suppressing mitogen-activated protein kinase signaling, negatively regulates the transactivation activity of hypoxia-inducible factor 1α (HIF-1α) by inhibiting formation of HIF-1α/p300 complex and suppressing VEGF transcription, thereby reducing hypoxia-induced VEGF production. The expression level of RKTG is significantly downregulated in clinical ccRCC tumor samples, with an inverse correlation with VEGF expression level. These results highlight the functional roles of RKTG and its regulated Raf/ERK/MEK signaling cascade in angiogenesis and autocrine VEGF signaling. In addition, this study indicates that RKTG is likely implicated in the development of ccRCC through its regulation on angiogenesis.