title: Loss of TET2 in hematopoietic cells leads to DNA hypermethylation of active enhancers and induction of leukemogenesis.
abstract: 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 CG dinucleotide (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 preleukemic 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 increases relative to population doublings. We confirmed 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 down-regulated 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 contributes to increased stem cell proliferation and leukemogenesis.
authors.affiliation: Biotech Research and Innovation Centre (BRIC), University of Copenhagen, 2200 Copenhagen, Denmark; Centre for Epigenetics, University of Copenhagen, 2200 Copenhagen, Denmark;
authors.forename: Kasper D
authors.initials: KD
authors.lastname: Rasmussen
authors.affiliation: Biotech Research and Innovation Centre (BRIC), University of Copenhagen, 2200 Copenhagen, Denmark; Centre for Epigenetics, University of Copenhagen, 2200 Copenhagen, Denmark;
authors.forename: Guangshuai
authors.initials: G
authors.lastname: Jia
authors.affiliation: Biotech Research and Innovation Centre (BRIC), University of Copenhagen, 2200 Copenhagen, Denmark;
authors.forename: Jens V
authors.initials: JV
authors.lastname: Johansen
authors.affiliation: Biotech Research and Innovation Centre (BRIC), University of Copenhagen, 2200 Copenhagen, Denmark; Centre for Epigenetics, University of Copenhagen, 2200 Copenhagen, Denmark;
authors.forename: Marianne T
authors.initials: MT
authors.lastname: Pedersen
authors.affiliation: Biotech Research and Innovation Centre (BRIC), University of Copenhagen, 2200 Copenhagen, Denmark; The Danish Stem Cell Center (Danstem), University of Copenhagen, 2200 Copenhagen, Denmark; Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen, Denmark; The Finsen Laboratory, Rigshospitalet, 2200 Copenhagen, Denmark;
authors.forename: Nicolas
authors.initials: N
authors.lastname: Rapin
authors.affiliation: Biotech Research and Innovation Centre (BRIC), University of Copenhagen, 2200 Copenhagen, Denmark; The Danish Stem Cell Center (Danstem), University of Copenhagen, 2200 Copenhagen, Denmark; Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen, Denmark; The Finsen Laboratory, Rigshospitalet, 2200 Copenhagen, Denmark;
authors.forename: Frederik O
authors.initials: FO
authors.lastname: Bagger
authors.affiliation: Biotech Research and Innovation Centre (BRIC), University of Copenhagen, 2200 Copenhagen, Denmark; The Danish Stem Cell Center (Danstem), University of Copenhagen, 2200 Copenhagen, Denmark; Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen, Denmark; The Finsen Laboratory, Rigshospitalet, 2200 Copenhagen, Denmark;
authors.forename: Bo T
authors.initials: BT
authors.lastname: Porse
authors.affiliation: INSERM U985, Institut Gustave Roussy, 94805 Villejuif, France.
authors.forename: Olivier A
authors.initials: OA
authors.lastname: Bernard
authors.affiliation: Biotech Research and Innovation Centre (BRIC), University of Copenhagen, 2200 Copenhagen, Denmark; Centre for Epigenetics, University of Copenhagen, 2200 Copenhagen, Denmark;
authors.forename: Jesper
authors.initials: J
authors.lastname: Christensen
authors.affiliation: Biotech Research and Innovation Centre (BRIC), University of Copenhagen, 2200 Copenhagen, Denmark; Centre for Epigenetics, University of Copenhagen, 2200 Copenhagen, Denmark; The Danish Stem Cell Center (Danstem), University of Copenhagen, 2200 Copenhagen, Denmark; kristian.helin@bric.ku.dk.
authors.forename: Kristian
authors.initials: K
authors.lastname: Helin
mesh_terms: D000818:Animals; D063646:Carcinogenesis / Q000235:genetics*; D049109:Cell Proliferation / Q000235:genetics; D019175:DNA Methylation / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000235:genetics*; D049308:Dioxygenases; D004742:Enhancer Elements, Genetic / Q000235:genetics*; D015972:Gene Expression Regulation, Neoplastic; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000473:pathology*; D006801:Humans; D051379:Mice; D009154:Mutation / Q000235:genetics; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D014178:Translocation, Genetic / Q000235:genetics
chemical_list: D004268:DNA-Binding Proteins; D011518:Proto-Oncogene Proteins; D049308:Dioxygenases; C551914:Tet2 protein, mouse
keywords: DNA methylation; TET2; enhancer; leukemia