Cancer is a disease of both genetic and epigenetic changes. While increasing evidence demonstrates that oncogenic progression entails chromatin-mediated changes such as DNA methylation, the role of histone variants in cancer initiation and progression currently remains unexplored. Here, we report that the histone variant macroH2A (mH2A) suppresses tumour progression of malignant melanoma.
The histone variant macroH2A suppresses melanoma progression through regulation of CDK8.
Specimen part, Disease
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Histone Variant H2A.Z.2 Mediates Proliferation and Drug Sensitivity of Malignant Melanoma.
Cell line
View SamplesHere we report a novel role for H2A.Z.2 (H2AFV) as a mediator of cell proliferation and sensitivity to targeted therapies in malignant melanoma. While both H2A.Z.1 and H2A.Z.2 are highly expressed in metastatic melanoma and correlate with decreased patient survival, only H2A.Z.2 deficiency results in impaired cellular proliferation of melanoma cells, which occurs via a G1/S arrest. Integrated gene expression and ChIP-seq analyses revealed that H2A.Z.2 positively regulates E2F target genes, and that such genes acquire a distinct H2A.Z occupancy signature over the promoter and gene body in metastatic melanoma cells. We further identified the BET family member BRD2 as an H2A.Z-interacting protein in melanoma cells, and demonstrate that H2A.Z.2 silencing cooperates with BET inhibition to induce cell death.
Histone Variant H2A.Z.2 Mediates Proliferation and Drug Sensitivity of Malignant Melanoma.
Cell line
View SamplesHere we report a novel role for H2A.Z.2 (H2AFV) as a mediator of cell proliferation and sensitivity to targeted therapies in malignant melanoma. While both H2A.Z.1 and H2A.Z.2 are highly expressed in metastatic melanoma and correlate with decreased patient survival, only H2A.Z.2 deficiency results in impaired cellular proliferation of melanoma cells, which occurs via a G1/S arrest. Integrated gene expression and ChIP-seq analyses revealed that H2A.Z.2 positively regulates E2F target genes, and that such genes acquire a distinct H2A.Z occupancy signature over the promoter and gene body in metastatic melanoma cells. We further identified the BET family member BRD2 as an H2A.Z-interacting protein in melanoma cells, and demonstrate that H2A.Z.2 silencing cooperates with BET inhibition to induce cell death. Overall design: Expression levels for non tumorigenic (Melanocytes) and human melanoma cell line SKmel147, before and after JQ1 treatement
Histone Variant H2A.Z.2 Mediates Proliferation and Drug Sensitivity of Malignant Melanoma.
No sample metadata fields
View SamplesThe essential histone variant H2A.Z affects various DNA-based biological processes by so far not well understood mechanisms. Using a comprehensive label-free quantitative mass spectrometry-based approach we identified the human H2A.Z nucleosome interactome providing further insights into H2A.Z’s regulatory functions. Besides histone modification writer, eraser and reader complexes we identified PWWP2A as a novel H2A.Z-nucleosome binder. PWWP2A binds unprecedented strong to chromatin through a concerted multivalent binding mode. Two internal protein regions separately allow H2A.Z-specificity and nucleosome interaction, whereas the PWWP domain mediates direct DNA binding. PWWP2A is found at euchromatic regions where it preferable binds to the H2A.Z-nucleosome-containing transcriptional start sites of transcribed genes. Cellular depletion of PWWP2A results in impaired proliferation caused by a mitotic delay likely due to deregulation of involved target genes. According with the strong cellular phenotype, knockdown of frog PWWP2A leads to severe developmental cranial facial defects arising from neural crest cell differentiation and migration problems. Together, this study identifies PWWP2A as an H2A.Z-specific multivalent chromatin binder and provides a novel link between H2A.Z, chromosome segregation and organ development. Overall design: RNASeq of HeLa cells treated with control or PWWP siRNA
Multivalent binding of PWWP2A to H2A.Z regulates mitosis and neural crest differentiation.
No sample metadata fields
View SamplesPrevious studies have revealed that UV-stimulation of a variety of cells leads to activation of the EGF receptor, induction of Egr1, growth inhibition and apoptosis. On the other hand both Egr1 and EGF receptor activation are implicated in promoting the progression of prostate cancer. We treated M12 tumorigenic prostate epithelial cells which express little Egr1 with UV irradiation which rapidly activated the EGF receptor and elevated Egr1. Treatment with specific EGFR and ERKI/II inhibitors (PD153035 and UO126, respectively) confirmed that the upregulation of Egr1 was downstream of EGFR and ERKI/II Map kinase pathway. ChIP on chip experiments using Egr1 antibody identified 288 significantly bound promoters upon UV stimulation. Of these target genes, 40% had consensus Egr1 site in their promoters, considerably greater than that expected by chance (p < 0.005). The array binding results were validated by PCR analysis of 25 genes using DNA from conventional IP experiment. Affymetrix gene expression analysis of UV treated and control cells confirmed that a significant number of these bound promoters showed gene expression changes. Addition of siRNA to Egr1 confirmed that the gene expression changes were dependent upon Egr1 expression. Addition of EGF led to similar expression changes for nine tested genes. Proliferation and apoptosis assays confirmed that M12 cells undergo growth arrest and apoptosis following UV irradiation. Moreover, addition of EGF also promoted significant growth inhibition. These results indicate the M12 cells undergo a EGF receptor dependent apoptosis response upon UV-stimulation and that Egr1 mediates the regulation of numerous genes downstream of the EGF receptor that are associated with this response.
Egr1 regulates the coordinated expression of numerous EGF receptor target genes as identified by ChIP-on-chip.
No sample metadata fields
View SamplesAs rats do not develop neuropathic pain like hypersensitivity as neonates post nerve injury but do as adults we have used these arrays to help define the processes involved in this process.
T-cell infiltration and signaling in the adult dorsal spinal cord is a major contributor to neuropathic pain-like hypersensitivity.
Specimen part, Treatment
View SamplesSialic acids on vertebrate cell surfaces mediate many biological roles. Altered expression of certain sialic acid types or their linkages can have prognostic significance in human cancer. A classic but unexplained example is enhanced 2-6-sialylation on N-glycans, resulting from over-expression of the Golgi enzyme -galactoside:2-6-sialyltransferase (ST6Gal-I). Previous data supporting a role for the resulting Sia2-3Gal1-4GlcNAc (Sia6LacNAc) structure in tumor biology were based on in vitro studies in transfected carcinoma cells, in which increased Sia6LacNAc on 1-integrins enhanced their binding to ligands, and stimulated cell motility. Here we examine for the first time the in vivo role of the ST6Gal-I enzyme in the growth and differentiation of spontaneous mammary cancers in mice transgenic for an MMTV-promoter-driven polyoma-middle-T antigen, a tumor in which beta1-integrin function is important for tumorigenesis, and in maintaining the proliferative state of tumor cells. Tumors induced in St6gal1 null animals were more differentiated in comparison to those in the wild-type background, both by histological analysis and by protein expression profiles. Furthermore, we show the St6gal1 null tumors have selectively altered expression of genes associated with focal adhesion signaling, and have decreased phosphorylation of FAK, a downstream target of 1-integrins. This first in vivo evidence for a role of ST6Gal-I in tumor progression was confirmed using a novel approach, which conditionally restored St6gal1 in cell lines derived from the null tumors. These findings indicate a role for ST6Gal-I as a mediator of tumor progression, with its expression causing a less differentiated phenotype, via enhanced 1-integrin function.
alpha 2-6-Linked sialic acids on N-glycans modulate carcinoma differentiation in vivo.
Sex, Age, Specimen part
View SamplesAnopheles gambiae mosquitoes play an important role in malaria transmission. In sub-Saharan Africa, the dry season can last several months. The mechanisms for mosquito population to survive through the dry season are poorly understood. One possible mechanism is that adults increase their desiccation tolerance over the dry season. Genetic analyses have shown that inversions 2La, 2Rb, 2Rc, 2Rd and 2Ru are associated with aridity resistance, however little is known about the transcriptional response of genes in response to desiccation.
Genome-wide transcriptional analysis of genes associated with acute desiccation stress in Anopheles gambiae.
Specimen part
View SamplesBackground: Central nervous system (CNS) metastases represent a major problem in the treatment of HER2-positive breast cancer due to the disappointing efficacy of HER2-targeted therapies in the brain microenvironment. The antibody-drug conjugate ado-trastuzumab emtansine (T-DM1) has shown efficacy in trastuzumab-resistant systemic breast cancer. Here, we tested the hypothesis that T-DM1 could overcome trastuzumab resistance in preclinical models of brain metastases.
Preclinical Efficacy of Ado-trastuzumab Emtansine in the Brain Microenvironment.
Specimen part, Disease, Time
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