Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Vitamin C induced epigenomic remodeling in IDH1 mutant acute myeloid leukemia

ABSTRACT: The genomes of myeloid malignancies are characterized by epigenomic abnormalities. Heterozygous, inactivating TET2 mutations and neomorphic IDH mutations are recurrent and mutually exclusive in acute myeloid leukemia (AML) genomes. Ascorbic Acid (vitamin C) has been shown to stimulate the catalytic activity of TET2 in vitro and thus we sought to explore its effect in a leukemic model expressing IDH1R132H. Vitamin C treatment induced an IDH1R132H dependent reduction in cell proliferation and an increase in expression of genes involved in leukocyte differentiation. Vitamin C induced differentially methylated regions (DMRs) that displayed a significant overlap with enhancers implicated in myeloid differentiation and were enriched in sequence elements for the hematopoietic transcription factors RUNX1 and PU.1. ChIP-seq of PU.1 and RUNX1 revealed a significant loss of PU.1 and increase of RUNX1 bound DNA elements accompanied by their demethylation following vitamin C treatment. Additionally, vitamin C induced an increase in H3K27ac flanking sites bound by RUNX1. Based on these data we propose a model of vitamin C induced epigenetic remodelling of transcription factor binding sites driving differentiation in a leukemic model.

ORGANISM(S): Mus musculus

PROVIDER: GSE87623 | GEO | 2017/07/01

SECONDARY ACCESSION(S): PRJNA345426

REPOSITORIES: GEO

ACCESS DATA

Json Xml

Similar Datasets

PU.1-dependent enhancer inhibition separates clonal hematopoiesis from malignant transformation (RNA-Seq)

Project description:Hematopoietic stem cells sustain life-long blood production. While they are the known cellular origin of aging-associated myeloid malignancies, such as acute myeloid leukemia (AML), mechanisms driving their malignant transformation have remained elusive. Epigenetic dysregulation following acquired loss-of-function mutations of DNA methyl-cytosine dioxygenase Ten-Eleven Translocation-2 (TET2) occurs frequently in the elderly leading to cytosine hypermethylation in and around DNA binding sites of master transcription factors, including PU.1. Here we show that Tet2 deficient hematopoietic stem and progenitor cells (HSPC) undergo malignant transformation upon compromised PU.1 gene regulation. Leukemic stem and progenitor cells show hypermethylation at PU.1 binding sites and fail to activate PU.1-depenent myeloid enhancers, and are hallmarked by a defined signature of impaired genes shared with human AML. Our study demonstrates that Tet2 and PU.1 cooperate in suppressing leukemogenesis in HSPC and establishes a methylation sensitive PU.1-dependent gene network as a unifying feature in acute myeloid leukemia.

2022-07-31 | GSE186146 | GEO

PU.1-dependent enhancer inhibition separates clonal hematopoiesis from malignant transformation (oxBS-Seq)

2022-07-31 | GSE194170 | GEO

PU.1-dependent enhancer inhibition separates clonal hematopoiesis from malignant transformation (ATAC-Seq)

2022-07-31 | GSE191052 | GEO

Loss of TET2 in hematopoietic cells leads to DNA hypermethylation of active enhancers and induction of leukemogenesis [Agilent]

Project description:DNA methylation is tightly regulated throughout mammalian development and altered DNA methylation patterns are a general hallmark of cancer. The methylcytosine dioxygenase TET2 is frequently mutated in hematological disorders, including acute myeloid leukemia (AML), and has been suggested to protect CpG islands and promoters from aberrant DNA methylation. In this study, we present a novel Tet2-dependent leukemia mouse model that closely recapitulates gene expression profiles and hallmarks of human AML1-ETO induced AML. Using this model, we show that the primary effect of Tet2 loss in pre-leukemic hematopoietic cells is progressive and widespread DNA hypermethylation affecting up to 25% of active enhancer elements. In contrast, CpG island and promoter methylation does not change in a Tet2-dependent manner, but increase relative to population doublings. We confirm this specific enhancer hypermethylation phenotype in human AML patients with TET2 mutations. Analysis of immediate gene expression changes reveals rapid deregulation of a large number of genes implicated in tumorigenesis, including many downregulated tumor suppressor genes. Hence, we propose that TET2 prevents leukemic transformation by protecting enhancers from aberrant DNA methylation, and that it is the combined silencing of several tumor suppressor genes in TET2-mutated hematopoietic cells that contribute to increased stem cell proliferation and leukemogenesis. Gene expression profiles (Agilent SurePrint G3 Mouse GE 8x60K arrays) of FACS-sorted in vivo GMP cells (Lin-cKit+Sca1-CD16/32+CD150-) isolated from bone marrow of recipient mice one month after transplantation of WT bone marrow or splenic cells from two independent moribond Tet2-/-:AE leukemic mice (LeuA/AE1), or LeuB/AE3)

2015-04-30 | E-GEOD-68415 | biostudies-arrayexpress

Genome-wide binding pattern of PU.1 in normal erythroid progenitors and erythroleukemia cells

Project description:We find that the myeloid master regulatory transcription factor, PU.1, binds to >16,000 sites in both normal and leukemic erythroid cells. Of these bound sites, ~7,000 lie within 2kb of TSS of a gene, suggesting PU.1 may regulate a large number of genes in erythroid cells. Coupling this data with gene expression analysis, we show PU.1 directly regulates several critical signaling pathways in erythroid cells. Assaying PU.1 occupancy in normal and leukemic erythroid cells

2011-06-23 | E-GEOD-21950 | biostudies-arrayexpress

Tet2 facilitates the de-repression of myeloid target genes during C/EBPa induced transdifferentiation of pre-B cells

Project description:Tet2 is an enzyme that hydroxylates methylated cytosines and has been implicated in hematopoietic differentiation and the formation of myeloid malignancies when mutated. An ideal system to study the role of Tet2 in myelopoeisis is C/EBPa induced transdifferentiation of pre-B cells into macrophages, where many myeloid genes become rapidly upregulated. Here we found that C/EBPa binds to upstream regions of Tet2 and that the gene becomes activated. Tet2 knockdowns impaired the upregulation of macrophage markers as well as phagocytic capacity, suggesting that the enzyme is required for both early and late stages of myeloid differentiation. A slightly weaker effect was seen in primary cells with a Tet2 ablation. Expression arrays of transdifferentiating cells with Tet2 knockdowns permitted the identification of a small subset of myeloid genes whose upregulation was blunted. Activation of these target genes was accompanied by a rapid increase of promoter hydroxy-methylation. Our observations indicate that Tet2 helps C/EBPa to rapidly de-repress myeloid genes during the conversion of pre-B cells into macrophages. Gene expression was measured in a control and Tet2kd mouse preB cell line (called Haftl) harboring an inducible form of C/EBPa. Expression was measured in starting cells and cells induced to transdifferentiate into macrophage-like cells for 24 hours. Technical duplicates for each treatment and time were assayed.

2012-07-26 | E-GEOD-39666 | biostudies-arrayexpress

Transcription profiling of hematopoietic stem cells in the preleukemic phase from wiltype mice and mice deficient in transcription factor PU.1 to identify transcriptional changes preceding malignant transformation

Project description:Knockdown of the transcription factor PU.1 (Spi1) leads to acute myeloid leukemia (AML) in mice. We examined the transcriptome of PU.1 knockdown hematopoietic stem cells (HSC) in the preleukemic phase by linear amplification and genome-wide array analysis to identify transcriptional changes preceding malignant transformation. Hierarchical cluster analysis and principal component analysis clearly distinguished PU.1 knockdown from wildtype HSC. Jun family transcription factors c-Jun and JunB were among the top downregulated targets. Retroviral restoration of c-Jun expression in bone marrow cells of preleukemic mice partially rescued the PU.1-initiated myelomonocytic differentiation block. Lentiviral restoration of JunB at the leukemic stage led to reduced clonogenic growth, loss of leukemic self-renewal capacity, and prevented leukemia in transplanted NOD-SCID mice. Examination of 305 AML patients confirmed the correlation between PU.1 and JunB downregulation and suggests its relevance in human disease. These results delineate a transcriptional pattern that precedes the leukemic transformation in PU.1 knockdown HSC and demonstrate that decreased levels of c-Jun and JunB contribute to the development of PU.1-induced AML by blocking differentiation (c-Jun) and increasing self-renewal (JunB). Therefore, examination of disturbed gene expression in HSC can identify genes whose dysregulation is essential for leukemic stem cell function and are targets for therapeutic interventions. Experiment Overall Design: Total RNA of HSC of PU.1 knockdown or wildtype animals (3 pools of 3 animals each) was amplified by two rounds of RT and T7 promoter-based in-vitro transcription and the resultant biotinylated cRNA was then hybridized to Affymetrix Mouse Genome 430 2.0 arrays.

2007-11-22 | E-GEOD-5654 | biostudies-arrayexpress

Bacterial translocation is required for pre-leukemic myeloproliferation in Tet2 deficient mice

Project description:Ten-Eleven-translocation (Tet2) encodes an epigenetic modifier enzyme and is mutated somatically during age-associated clonal hematopoiesis of indeterminate potential (CHIP) as well as in myeloid malignancies 1-7. Tet2 deficiency leads to increased hematopoietic stem cell (HSC) renewal in human 7 and mouse 8. However, the development of myeloproliferation and myeloid malignancies occurs at late age, and only occasionally in humans 2,6,7,9 and in 50-75% of Tet2 deficient animals 8,10,11, suggesting that undefined triggers are required for pre-leukemic myeloid expansion. Our studies reveal that Tet2 deficient mice can exhibit high levels of plasma IL-6, systemic dissemination of indigenous gut bacteria and increased intestinal permeability that correlate with the development of a pre-leukemic myeloproliferative phenotype. Increased intestinal permeability was linked to a large number of transcriptional changes in the jejunum, especially among genes involved in defense response to bacterium and intestinal barrier function. Strikingly, antibiotic treatment reduced plasma IL-6 levels and both, prevented early myeloid expansion and reversed the pre-leukemic myeloproliferative phenotype in Tet2-/- mice. In summary, we show that Tet2 deficiency promotes intestinal bacterial translocation and subsequent systemic inflammation, and that gut-derived microbial signals are required for the development of pre-leukemic myeloproliferation in a Tet2-deficient host. Our studies suggest that controlling bacterial translocation and bacteria-associated systemic inflammation could decrease the risk of myeloid malignancies significantly in individuals with somatic Tet2 mutations.

2018-03-15 | GSE99333 | GEO

Loss of TET2 in hematopoietic cells leads to DNA hypermethylation of active enhancers and induction of leukemogenesis (Affymetrix)

2015-04-22 | GSE59586 | GEO

Loss of TET2 in hematopoietic cells leads to DNA hypermethylation of active enhancers and induction of leukemogenesis (eRRBS)

2015-04-22 | GSE59584 | GEO