Project description:Human renal cell carcinomas (RCC) have differential expression of HIF-1alpha and HIF-2alpha, depending on VHL genotype and other events. Here, we have divided a series of RCC samples for HIF-alpha expression and VHL genotype, in order to define differentially expressed genes Keywords: Patient Sample Study A total of 57 frozen RCC samples were stained for HIF-1alpha and HIF-2alpha, and genotyped for VHL. 5 VHL WT/HIF-negative, 8 VHL-deficient/HIF-1alpha+/HIF-2alpha+ and 8 VHL-deficient/HIF-2alpha+ tumors were selected for microarray
Project description:Human renal cell carcinomas (RCC) have differential expression of HIF-1alpha and HIF-2alpha, depending on VHL genotype and other events. Here, we have divided a series of RCC samples based on HIF-alpha expression, in order to examine levels of genomic DNA aberration. Keywords: Patient Sample Study A total of 57 frozen RCC samples were stained for HIF-1alpha and HIF-2alpha, and genotyped for VHL. 10 VHL-deficient/HIF-1alpha+/HIF-2alpha+ and 11 VHL-deficient/HIF-2alpha+ tumors were selected for array CGH.
Project description:Human renal cell carcinomas (RCC) have differential expression of HIF-1alpha and HIF-2alpha, depending on VHL genotype and other events. Here, we have divided a series of RCC samples for HIF-alpha expression and VHL genotype, in order to define differentially expressed genes Keywords: Patient Sample Study
Project description:Human renal cell carcinomas (RCC) have differential expression of HIF-1alpha and HIF-2alpha, depending on VHL genotype and other events. Here, we have divided a series of RCC samples based on HIF-alpha expression, in order to examine levels of genomic DNA aberration. Keywords: Patient Sample Study
Project description:HIF-2alpha is essential for (VHL-/-) ccRCC subcutaneous tumor growth in mice, and in tumor cell lines, its inhibition results in increased ROS accumulation, tumor cell death and responsiveness to radiation treatment. We have utilized transcriptional profiling to screen for putative HIF-2alpha targets genes that serve an anti-oxidant and, thus, cell survival function. A498 ccRCC cell line was treated with control siRNA or mixture of two HIF-2alpha specific siRNA for 48 hours, and RNA was harvested. 4 independent experiments were performed, and expression was compared between control and HIF-2alpha knockdown groups.
Project description:HIF-2alpha is essential for (VHL-/-) ccRCC subcutaneous tumor growth in mice, and in tumor cell lines, its inhibition results in increased ROS accumulation, tumor cell death and responsiveness to radiation treatment. We have utilized transcriptional profiling to screen for putative HIF-2alpha targets genes that serve an anti-oxidant and, thus, cell survival function. A498 ccRCC cell line was treated with control siRNA or mixture of two HIF-2alpha specific siRNA for 48 hours, and RNA was harvested. 4 independent experiments were performed, and expression was compared between control and HIF-2alpha knockdown groups. 8 total samples were applied to Affymetrix Human Gene 1.0 ST Arrays. We performed two-class paired analysis using Significance Analysis of Microarrays (SAM) software to compare expression in the CT (control siRNA) and H2 (Hif2-alpha siRNA) groups.
Project description:Mutational inactivation of VHL is the earliest genetic event in the majority of ccRCCs, leading to activation of the HIF-1α and HIF-2α transcription factors. While correlative studies of human ccRCCs and functional studies using human ccRCC cell lines have implicated HIF-1α as an inhibitor and HIF-2α as a promoter of aggressive tumour behaviours, their roles in tumour onset have not been functionally addressed. Using an autochthonous ccRCC model, we show genetically that Hif1a is necessary for tumour formation whereas Hif2a deletion has only minor effects on tumour initiation and growth. Both HIF-1α and HIF-2α are necessary for the clear cell phenotype. Transcriptomic and proteomic analyses revealed that HIF-1α regulates glycolysis while HIF-2α regulates genes associated with lipoprotein metabolism, ribosome biogenesis and E2F and MYC transcriptional activities. Deficiency of HIF-2α increased CD8+ T cell infiltration and activation. These studies reveal different functions of HIF-1α and HIF-2α in ccRCC. SIGNIFICANCE The roles of HIF-1α and HIF-2α in ccRCC pathogenesis remain unclear. Using a mouse genetic approach we show that HIF-1α but not HIF-2α is important for tumour formation, contrary to predictions from studies of human ccRCC. We show that HIF-1α and HIF-2α transcriptionally regulate different aspects of metabolism and identify HIF-2α as a suppressor of immune cell infiltration and activation.
Project description:Mutational inactivation of VHL is the earliest genetic event in the majority of clear cell renal cell carcinomas (ccRCC), leading to accumulation of the HIF-1alpha and HIF-2a transcription factors. While correlative studies of human ccRCC and functional studies using human ccRCC cell lines have implicated HIF-1a as an inhibitor and HIF-2a as a promoter of aggressive tumour behaviours, their roles in tumour onset have not been functionally addressed. Using an autochthonous ccRCC model, we show genetically that Hif1a is essential for tumour formation whereas Hif2a deletion has only minor effects on tumour initiation and growth. Both HIF-1a and HIF-2a are required for the clear cell phenotype. Transcriptomic and proteomic analyses revealed that HIF-1alpha regulates glycolysis while HIF-2a regulates genes associated with lipoprotein metabolism, ribosome biogenesis and E2F and MYC transcriptional activities. HIF-2a-deficient tumours were characterised by increased antigen presentation, interferon signalling and CD8+ T cell infiltration and activation. Single copy loss of HIF1A or high levels of HIF2A mRNA expression correlated with altered immune microenvironment in human ccRCC. These studies reveal an oncogenic role of HIF-1alpha in ccRCC initiation and suggest that alterations in the balance of HIF-1alpha and HIF-2a activities can affect different aspects of ccRCC biology and disease aggressiveness.
Project description:Human clear cell renal cell carcinoma (ccRCC) is a common cancer of the kidney. We applied an integrated approach to identify important factors that influence carcinogenesis in ccRCC. 33 frozen ccRCC samples were subject to copy number analysis. The data was analyzed to identify factors affecting tumorigenesis. The samples were also stained for HIF-1alpha and HIF-2alpha expression. The tumors were subtyped based on HIF expression and investigated for differences in genetic aberrations.
Project description:Inactivation of the von Hippel-Lindau tumor suppressor gene, VHL, is an archetypical tumor-initiating event in clear cell renal carcinoma (ccRCC) that leads to the activation of hypoxia-inducible transcription factors (HIFs). However, VHL mutation status in ccRCC is not correlated with clinical outcome. Here we show that during ccRCC progression, cancer cells exploit diverse epigenetic alterations to empower a branch of the VHL-HIF pathway for metastasis, and the strength of this activation is associated with poor clinical outcome. By analyzing metastatic subpopulations of VHL-deficient ccRCC cells, we discovered an epigenetically altered VHL-HIF response that is specific to metastatic ccRCC. Focusing on the two most prominent pro-metastatic VHL-HIF target genes, we show that loss of polycomb repressive complex 2 (PRC2)-dependent histone H3 Lys27 trimethylation (H3K27me3) activates HIF-driven chemokine (C-X-C motif) receptor 4 (CXCR4) expression in support of chemotactic cell invasion, whereas loss of DNA methylation enables HIF-driven cytohesin 1 interacting protein (CYTIP) expression to protect cancer cells from death cytokine signals. Thus, metastasis in ccRCC is based on an epigenetically expanded output of the tumor-initiating pathway. This SuperSeries is composed of the SubSeries listed below. Refer to individual Series.