Project description:Changes in translational efficiency of mRNAs consequent on alteration of HIF and/or mTOR pathway activity in VHL-defective kidney cancer cell were analysed. High-resolution polysome profiling followed by sequencing of the 5′ ends of mRNAs (HP5) was used to measure translational efficiency of mRNAs resolved by their transcription start sites. HP5 was applied to VHL-defective kidney cancer cell lines with or without VHL reintroduction and/or mTOR inhibition with Torin 1 treatment. In addition, the contribution of HIF2A/EIF4E2 pathway was assessed using 786-O cells in which EIF4E2 was inactivated.
Project description:VHL loss is the most common genetic alteration event in ccRCC. VHL loss stabilizes hypoxia-inducible factor-2 alpha (HIF2a). We compared the changes in transcriptomics profiles after VHL restoration or HIF2a siRNA knockdown in 786-O cells.
Project description:Expression profiling of thymic lymphomas derived from HIF1a+/+, p53R270H/R270H; HIF1a+/-, p53R270H/R270H; and HIF1aKI/+, p53R270H/R270H mice. HIF1a and HIF2a share a high degree of sequence homology, but recent work has shown that the two a subunits can have contrasting and tissue-specific effects on tumor growth. To directly compare the role of each HIFa subunit in spontaneous tumorigenesis, we bred a mouse model of expanded HIF2a expression and Hif1a+/- mice to homozygotes for the R270H mutation in p53. Heterozygosity for Hif1a significantly reduced the incidence of thymic lymphomas observed in this model. Moreover, reduced Hif1a levels correlated with decreased stabilization of activated Notch1 and expression of the Notch target genes, Dtx1 and Nrarp. Keywords: genetic modification, disease state analysis Thymic lymphoma tissue was preserved at the time mice were sacrificed. 4-5 samples from each of 3 genotypes (HIF1a+/-, p53R270H/R270H, HIF1aKI/+; p53R270H/R270H; and HIF1a+/+, p53R270H/R270H) were then used for microarray analysis to identify differences in gene expression that could account for changes in tumor onset and incidence.
Project description:SILAC based protein correlation profiling using size exclusion of protein complexes derived from Mus musculus tissues (Heart, Liver, Lung, Kidney, Skeletal Muscle, Thymus)
Project description:SILAC based protein correlation profiling using size exclusion of protein complexes derived from seven Mus musculus tissues (Heart, Brain, Liver, Lung, Kidney, Skeletal Muscle, Thymus)
Project description:HIF2a function is both necessary and sufficient for the growth of VHL-null clear cell Renal Cell Carcinoma (ccRCC). Targeting HIF2a function can therefore be a promising therapeutic strategy. We used microarray analysis to characterize a novel pharmacological inhibitor of HIF2a named PT2399. By comparing genes that are responsive to PT2399 in parental cells vs cells lacking HIF2a, by virtue of CRISPR-mediated genetic editing, we characterized gene signatures that are regulated by PT2399 in a HIF2a dependent manner. Cells were treated with either DMSO (control) or 2uM PT2399 for indicated time periods, total RNA was extracted and analyzed. Please note that the experiments with 786O Parental and HIF2a null cells were conducted independently.
Project description:HIF2a function is both necessary and sufficient for the growth of VHL-null clear cell Renal Cell Carcinoma (ccRCC). Targeting HIF2a function can therefore be a promising therapeutic strategy. We used microarray analysis to characterize a novel pharmacological inhibitor of HIF2a named PT2399. By comparing genes that are responsive to PT2399 in parental cells vs cells lacking HIF2a, by virtue of CRISPR-mediated genetic editing, we characterized gene signatures that are regulated by PT2399 in a HIF2a dependent manner.
Project description:Introgressed variants from other species can be an important source of genetic variation because they may arise rapidly, can include multiple mutations on a single haplotype, and have often been pretested by selection in the species of origin. Although introgressed alleles are generally deleterious, several studies have reported introgression as the source of adaptive alleles-including the rodenticide-resistant variant of Vkorc1 that introgressed from Mus spretus into European populations of Mus musculus domesticus. Here, we conducted bidirectional genome scans to characterize introgressed regions into one wild population of M. spretus from Spain and three wild populations of M. m. domesticus from France, Germany, and Iran. Despite the fact that these species show considerable intrinsic postzygotic reproductive isolation, introgression was observed in all individuals, including in the M. musculus reference genome (GRCm38). Mus spretus individuals had a greater proportion of introgression compared with M. m. domesticus, and within M. m. domesticus, the proportion of introgression decreased with geographic distance from the area of sympatry. Introgression was observed on all autosomes for both species, but not on the X-chromosome in M. m. domesticus, consistent with known X-linked hybrid sterility and inviability genes that have been mapped to the M. spretus X-chromosome. Tract lengths were generally short with a few outliers of up to 2.7 Mb. Interestingly, the longest introgressed tracts were in olfactory receptor regions, and introgressed tracts were significantly enriched for olfactory receptor genes in both species, suggesting that introgression may be a source of functional novelty even between species with high barriers to gene flow.
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:Hyperactivation of Notch signaling and the cellular hypoxic response are frequently observed in cancers, with increasing reports of connections to tumor initiation and progression. The two signaling mechanisms are known to intersect, but while it is well established that hypoxia regulates Notch signaling, less is known about whether Notch can regulate the cellular hypoxic response. We now report that Notch signaling specifically controls expression of HIF2a, a key mediator of the cellular hypoxic response. Transcriptional upregulation of HIF2a by Notch under normoxic conditions leads to elevated HIF2a protein levels in primary breast cancer cells as well as in human breast cancer, medulloblastoma and renal cell carcinoma cell lines. The elevated level of HIF2a protein was in certain tumor cell types accompanied by down-regulation of HIF1a protein levels, indicating that high Notch signaling may drive a HIF1a-to-HIF2a switch. At the transcriptome level, the presence of HIF2a was required for approximately 21% of all Notch-induced genes: among the 1062 genes that were upregulated by Notch in medulloblastoma cells during normoxia, upregulation was abrogated in 227 genes when HIF2a expression was knocked down by HIF2a siRNA. In conclusion, our data show that Notch signaling affects the hypoxic response via regulation of HIF2a, which may be important for future cancer therapies.