Project description:Results When compared with each other, primary tumors and regional metastases showed statistically indistinguishable gene expression patterns. Supervised analyses comparing patients with distant metastases versus primary tumors or regional metastases showed that the distant metastases were distinct and distinguished by the lack of expression of fibroblast/mesenchymal genes, and by the high expression of a 13-gene profile (that is, the ‘vascular endothelial growth factor (VEGF) profile’) that included VEGF, ANGPTL4, ADM and the monocarboxylic acid transporter SLC16A3. At least 8 out of 13 of these genes contained HIF1α binding sites, many are known to be HIF1α-regulated, and expression of the VEGF profile correlated with HIF1α IHC positivity. The VEGF profile also showed prognostic significance on tests of sets of patients with breast and lung cancer and glioblastomas, and was an independent predictor of outcomes in primary breast cancers when tested in models that contained other prognostic gene expression profiles and clinical variables. Conclusions These data identify a compact in vivo hypoxia signature that tends to be present in distant metastasis samples, and which portends a poor outcome in multiple tumor types.
Project description:Results When compared with each other, primary tumors and regional metastases showed statistically indistinguishable gene expression patterns. Supervised analyses comparing patients with distant metastases versus primary tumors or regional metastases showed that the distant metastases were distinct and distinguished by the lack of expression of fibroblast/mesenchymal genes, and by the high expression of a 13-gene profile (that is, the âvascular endothelial growth factor (VEGF) profileâ) that included VEGF, ANGPTL4, ADM and the monocarboxylic acid transporter SLC16A3. At least 8 out of 13 of these genes contained HIF1α binding sites, many are known to be HIF1α-regulated, and expression of the VEGF profile correlated with HIF1α IHC positivity. The VEGF profile also showed prognostic significance on tests of sets of patients with breast and lung cancer and glioblastomas, and was an independent predictor of outcomes in primary breast cancers when tested in models that contained other prognostic gene expression profiles and clinical variables. Conclusions These data identify a compact in vivo hypoxia signature that tends to be present in distant metastasis samples, and which portends a poor outcome in multiple tumor types. Microarrays and immunohistochemistry were used to analyze primary breast tumors, regional (lymph node) metastases, and distant metastases in order to identify biological features associated with distant metastases.
Project description:Histone modifications are now well-established regulators of transcriptional programs that distinguish distinct cell states. However, the kinetics of histone modification and their role in mediating rapid, signal-responsive changes in gene expression have been little studied on a genome-wide scale. Vascular endothelial growth factor A (VEGF), a major regulator of angiogenesis, rapidly triggers changes in transcriptional activity of human umbilical vein endothelial cells (HUVECs). Here we used chromatin immunoprecipitation and high throughput sequencing (ChIP-seq) to measure genome-wide changes in histone H3 acetylation at lysine 27 (H3K27ac), a marker of active enhancers {Kharchenko et al., 2011, Nature, 471, 480-5;Zentner et al., 2011, Genome Res, 21, 1273-83;Rada-Iglesias et al., 2011, Nature, 470, 279-83; Creyghton et al., 2010, Proc Natl Acad Sci U S A, 107, 21931-6 }, after 0, 1, 4, and 12 hours of VEGF stimulation. We show that sites with greatest H3K27ac changes were associated tightly with p300, a histone acetyltransferase. This dynamic H3K27ac signature defined transcriptional elements that are functionally linked to angiogenesis, participate in rapid VEGF-stimulated changes in chromatin conformation, and mediate VEGF-induced transcriptional responses. Dynamic H3K27ac deposition required p300 activity and did not involve altered nucleosome occupancy. Our results demonstrate that capture of dynamic changes in H3K27ac provides a new approach to define the activity of functional genomic elements and implicate epigenetic modifications in rapid signal-responsive transcriptional regulation. ChiP-seq timecourse of H3K27ac, ETS1, p300 chromatin occupancy, mRNA expression and DNA hypersensitivity of HUVEC cells stimulated with VEGF for 0, 1, 4, and 12 hours
Project description:This study aimed to investigate whether the BET inhibitor JQ1 could alter the hypoxia-induced upregulation of gene expression and have an anti-tumour effect associated with this mechanism. We showed JQ1 downregulates 44% of hypoxia upregulated genes, including CA9 and VEGF-A. We demonstrated that JQ1 reduces triple receptor negative breast cancer (TNBC) tumour growth in monolayer and spheroid (3D) cell culture.
Project description:Histone modifications are now well-established regulators of transcriptional programs that distinguish distinct cell states. However, the kinetics of histone modification and their role in mediating rapid, signal-responsive changes in gene expression have been little studied on a genome-wide scale. Vascular endothelial growth factor A (VEGF), a major regulator of angiogenesis, rapidly triggers changes in transcriptional activity of human umbilical vein endothelial cells (HUVECs). Here we used chromatin immunoprecipitation and high throughput sequencing (ChIP-seq) to measure genome-wide changes in histone H3 acetylation at lysine 27 (H3K27ac), a marker of active enhancers {Kharchenko et al., 2011, Nature, 471, 480-5;Zentner et al., 2011, Genome Res, 21, 1273-83;Rada-Iglesias et al., 2011, Nature, 470, 279-83; Creyghton et al., 2010, Proc Natl Acad Sci U S A, 107, 21931-6 }, after 0, 1, 4, and 12 hours of VEGF stimulation. We show that sites with greatest H3K27ac changes were associated tightly with p300, a histone acetyltransferase. This dynamic H3K27ac signature defined transcriptional elements that are functionally linked to angiogenesis, participate in rapid VEGF-stimulated changes in chromatin conformation, and mediate VEGF-induced transcriptional responses. Dynamic H3K27ac deposition required p300 activity and did not involve altered nucleosome occupancy. Our results demonstrate that capture of dynamic changes in H3K27ac provides a new approach to define the activity of functional genomic elements and implicate epigenetic modifications in rapid signal-responsive transcriptional regulation.
Project description:COVID-19 has been associated with high prevalences of retinal diseases in humans. However, cellular and molecular mechanisms that underly the COVID-19-associated retinopathy remains unknown. Here, we deployed a mouse COVID-19 model to investigate the causative link between SARS-CoV-2 infection and retinopathy development. Our data showed that COVID-19-induced pulmonary hypoxia triggered systemic hypoxia and markedly augmented VEGF expression levels in the retina and plasma. High VEGF levels altered vascular structures and functions in the retina, resulting in neovascularization, vascular disorganization and increased leakiness. We deployed a new terminology of coviretinopathy to accurately describe these COVID-19-induced pathological changes in the retina. Consequently, blocking VEGF by a specific neutralizing antibody (VEGF blockade) completely ablated the COVID-19-associated vascular changes in the retina. Together, these findings provide new mechanistic insights into the COVID-19-associated retinopathy and propose a new therapeutic paradigm for effective treatment of coviretinopathy.