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:We studied how leukemia-associated mutations subvert normal adult hematopoiesis by genetically inducing them in specifically in murine hematopoietic stem cells (HSC) followed by lineage tracing in native hosts. Leukemia-initiating mutations such as Tet2 or Dnmt3a deletions did not increase the net HSC contribution in the steady state, whereasTet2 deletion slightly accelerated HSC contribution to myeloid lineages following microbial stimulation. In contrast, the leukemia-transforming KrasG12D mutation dramatically accelerated the contribution of mutant HSC to all hematopoietic lineages, rapidly creating a pre-leukemic state. The acceleration was mediated by KrasG12D-carrying multipotent progenitors (MPP) that rapidly outcompeted normal MPP and showed increased proliferation but lacked self-renewal capacity. In addition, mutant progenitor cells expressed the secreted stem/progenitor regulator osteopontin and showed enhanced CXCR4-dependent motility, both of which contributed to the accelerated spread of the mutation to mature cells. Thus, transforming mutations may facilitate their spread from HSC to mature cells via hypercompetitive progenitors, creating a two-component stem/progenitor circuit that underlies leukemogenesis.
Project description:This is a mathematical model describing the hematopoietic lineages with leukemia lineages, as controlled by end-product negative feedback inhibition. Variables include hematopoietic stem cells, progenitor cells, terminally differentiated HSCs, leukemia stem cells, and terminally differentiated leukemia stem cells.
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:Genome wide DNA methylation profiling of leukemia stem, blast cells obtained from 15 AML patients and of normal hematopoietic stem/progenitor cells from 5 normal bone marrow. The Illumina Infinium 450k Human DNA methylation Beadchip was used to obtain DNA methylation profiles across approximately 450,000 CpGs in the samples. Samples included 20 leukemia stem cells, 24 blast cells and 30 normal hematopoietic stem and progenitor cells (6 different types from 5 normal bone marrows).
Project description:To interrogate the molecular pathways disrupted by Jak2V617F expression and/or Tet2 loss, Lin-negative, Sca-1-positive, c-kit-positive (LSK) hematopoietic progenitor cells were isolated from bone marrow of wild-type, Jak2V617F, Tet2-null or Jak2V617F/Tet2-null animals (n= 2-4 mice per group) and subjected to gene expression profiling.
Project description:To identify genes that are influenced by the catalytic and non-catalytic functions of Tet2 in hematopoietic stem and progenitor cells (HSPCs), we analyzed the gene expression profiles of Tet2 catalytic mutant (Tet2 Mut), Tet2 knockout (Tet2 KO) and wild-type HSPCs (or LSK, Lin–Sca-1+c-Kit+) and multi-potent progenitor (or MPP, Lin–) cells by RNA-seq.