Project description:Human leukemia cells treated with vitamin C for 12 and 72hrs and mouse hematopoietic progenitor cells with knockdown and Tet2 restoration
Project description: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.
Project description:We describe the proteomic composition of the secretome of fetal and adult hematopoietic progenitors during MLL-rearranged (MLLr) leukemia initiation as well as the pre-leukemic cells’ secretion response to the treatment with Fibulin (Fbln1) and/or Fibronectin (Fn1) using data-independent acquisition mass spectrometry analysis.
Project description:DNA methylation is tightly regulated throughout mammalian development and altered methylation patterns are a hallmark of cancer. The methylcytosine dioxygenase TET2 is frequently mutated in acute myeloid leukemia (AML) and has been suggested to protect CpG islands and promoters from aberrant methylation. By generating a novel mouse model of Tet2-deficient AML we show that loss of Tet2 in hematopoietic cells leads to progressive hypermethylation of active enhancer elements and altered expression of genes implicated in tumorigenesis. In contrast, CpG island and promoter methylation does not change in a Tet2-dependent manner. Furthermore, we confirm this specific enhancer hypermethylation phenotype in human AML patients. Thus, we propose that TET2 prevents leukemic transformation of hematopoietic cells by protecting enhancers from aberrant DNA methylation. Gene expression profiles from Tet2-/-;AML1-ETO and Tet2fl/fl;AML1-ETO in vitro-grown hematopoietic cells were compared using GeneChip Mouse Gene ST 2.0 Arrays (Affymetrix). Expression changes were investigated at early (passage 2) and late (passage 10) timepoints after Tet2 disruption.
Project description:DNA methylation is tightly regulated throughout mammalian development and altered methylation patterns are a hallmark of cancer. The methylcytosine dioxygenase TET2 is frequently mutated in acute myeloid leukemia (AML) and has been suggested to protect CpG islands and promoters from aberrant methylation. By generating a novel mouse model of Tet2-deficient AML we show that loss of Tet2 in hematopoietic cells leads to progressive hypermethylation of active enhancer elements and altered expression of genes implicated in tumorigenesis. In contrast, CpG island and promoter methylation does not change in a Tet2-dependent manner. Furthermore, we confirm this specific enhancer hypermethylation phenotype in human AML patients. Thus, we propose that TET2 prevents leukemic transformation of hematopoietic cells by protecting enhancers from aberrant DNA methylation. Enhanced Reduced Representation Bisulfite Sequencing (eRRBS) analysis of in vitro-grown hematopoietic cells transduced with AML1-ETO or MLL-AF9
Project description:DNA methylation is tightly regulated throughout mammalian development and altered methylation patterns are a hallmark of cancer. The methylcytosine dioxygenase TET2 is frequently mutated in acute myeloid leukemia (AML) and has been suggested to protect CpG islands and promoters from aberrant methylation. By generating a novel mouse model of Tet2-deficient AML we show that loss of Tet2 in hematopoietic cells leads to progressive hypermethylation of active enhancer elements and altered expression of genes implicated in tumorigenesis. In contrast, CpG island and promoter methylation does not change in a Tet2-dependent manner. Furthermore, we confirm this specific enhancer hypermethylation phenotype in human AML patients. Thus, we propose that TET2 prevents leukemic transformation of hematopoietic cells by protecting enhancers from aberrant DNA methylation. 5hmC-DIP-seq analysis for distribution of 5hmC in in vitro-grown hematopoietic cells transduced with AML1-ETO
Project description:Despite rapid advances in mapping genetic drivers and gene expression changes in hematopoietic stem cells (HSCs), there is a relative paucity of studies at the protein level. Here, we perform a deep, multi-omic characterization (epigenome, transcriptome and proteome) of HSCs carrying a loss-of-function mutation in Tet2, a key driver of increased self-renewal in blood cancers. Using state-of-the-art, multiplexed, low-input mass spectrometry (MS)-based proteomics, we profile wildtype (WT) and TET2-deficient (Tet2-/-) HSCs and show that the proteome captures previously unrecognized molecular processes which define the pre-leukemic HSC molecular landscape. Specifically, we obtain more accurate stratification of WT and Tet2-/- HSCs than transcriptomic approaches and identify extracellular matrix (ECM) molecules as novel points of dysregulation upon TET2 loss. HSC expansion assays using ECM-functionalized hydrogels confirm a selective effect on the expansion of Tet2-mutant HSCs. Taken together, our study represents a comprehensive molecular characterization of Tet2-mutant HSCs and identifies a previously unanticipated role of ECM molecules in regulating self-renewal of disease-driving HSCs.
Project description:DNA methylation is tightly regulated throughout mammalian development and altered methylation patterns are a hallmark of cancer. The methylcytosine dioxygenase TET2 is frequently mutated in acute myeloid leukemia (AML) and has been suggested to protect CpG islands and promoters from aberrant methylation. By generating a novel mouse model of Tet2-deficient AML we show that loss of Tet2 in hematopoietic cells leads to progressive hypermethylation of active enhancer elements and altered expression of genes implicated in tumorigenesis. In contrast, CpG island and promoter methylation does not change in a Tet2-dependent manner. Furthermore, we confirm this specific enhancer hypermethylation phenotype in human AML patients. Thus, we propose that TET2 prevents leukemic transformation of hematopoietic cells by protecting enhancers from aberrant DNA methylation. ChIP-seq analysis for distribution of H3K4me1, H3K27ac, and H3K4me3 histone marks in in vitro-grown hematopoietic cells transduced with AML1-ETO
Project description:Acute myeloid leukemia (AML) remains highly prone to relapse driven by therapy-persistent residual cells. To discover specific vulnerabilities in this population, we performed genome-wide CRISPR interference screens in AML cells treated with multiple agents. KHSRP was the top hit, whose depletion sensitized AML cells to therapy and substantially prolonged survival in treated AML-bearing mice. Profiling in vivo residual disease after therapy identified downregulation of the vitamin C and uric acid transporter SLC23A1 as a resistance mechanism. KHSRP depletion restored SLC23A1 through a previously unrecognized function by preventing ZC3H4-mediated nuclear mRNA degradation. KHSRP depletion therefore enhanced the synergistic cytotoxicity of vitamin C and uric acid, particularly in therapy-persistent leukemia cells. Re-expression of TET2 overrode the chemosensitizing effect of KHSRP depletion in TET2-mutant leukemia, suggesting that KHSRP phenotypes were linked to vitamin C and uric acid-mediated TET activation. These findings nominate targeting KHSRP to enhance treatment efficacy and selectively eradicate residual AML.