title: Essential role for Dnmt1 in the prevention and maintenance of MYC-induced T-cell lymphomas.
abstract: DNA cytosine methylation is an epigenetic modification involved in the transcriptional repression of genes controlling a variety of physiological processes, including hematopoiesis. DNA methyltransferase 1 (Dnmt1) is a key enzyme involved in the somatic inheritance of DNA methylation and thus plays a critical role in epigenomic stability. Aberrant methylation contributes to the pathogenesis of human cancer and of hematologic malignancies in particular. To gain deeper insight into the function of Dnmt1 in lymphoid malignancies, we genetically inactivated Dnmt1 in a mouse model of MYC-induced T-cell lymphomagenesis. We show that loss of Dnmt1 delays lymphomagenesis by suppressing normal hematopoiesis and impairing tumor cell proliferation. Acute inactivation of Dnmt1 in primary lymphoma cells rapidly induced apoptosis, indicating that Dnmt1 is required to sustain T-cell lymphomas. Using high-resolution genome-wide profiling, we identified differentially methylated regions between control and Dnmt1-deficient lymphomas, demonstrating a locus-specific function for Dnmt1 in both maintenance and de novo promoter methylation. Dnmt1 activity is independent of the presence of Dnmt3a or Dnmt3b in de novo promoter methylation of the H2-Ab1 gene. Collectively, these data show for the first time that Dnmt1 is critical for the prevention and maintenance of T-cell lymphomas and contributes to aberrant methylation by both de novo and maintenance methylation.
authors.affiliation: Department of Genetics, Cell Biology, and Anatomy, University of Nebraska Medical Center, Omaha, Nebraska, USA.
authors.forename: Staci L
authors.initials: SL
authors.lastname: Peters
authors.forename: Ryan A
authors.initials: RA
authors.lastname: Hlady
authors.forename: Jana
authors.initials: J
authors.lastname: Opavska
authors.forename: David
authors.initials: D
authors.lastname: Klinkebiel
authors.forename: Slavomira
authors.initials: S
authors.lastname: Novakova
authors.forename: Lynette M
authors.initials: LM
authors.lastname: Smith
authors.forename: Robert E
authors.initials: RE
authors.lastname: Lewis
authors.forename: Adam R
authors.initials: AR
authors.lastname: Karpf
authors.forename: Melanie A
authors.initials: MA
authors.lastname: Simpson
authors.forename: Lizhao
authors.initials: L
authors.lastname: Wu
authors.forename: Rene
authors.initials: R
authors.lastname: Opavsky
mesh_terms: D000818:Animals; D063646:Carcinogenesis / Q000235:genetics; D049109:Cell Proliferation; D002470:Cell Survival; D002478:Cells, Cultured; D000076123:DNA (Cytosine-5-)-Methyltransferase 1; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000502:physiology*; D019175:DNA Methylation; D044127:Epigenesis, Genetic; D015972:Gene Expression Regulation, Neoplastic; D006410:Hematopoiesis; D000949:Histocompatibility Antigens Class II / Q000235:genetics / Q000378:metabolism; D016399:Lymphoma, T-Cell / Q000235:genetics*; D051379:Mice; D008822:Mice, Transgenic; D011401:Promoter Regions, Genetic; D016271:Proto-Oncogene Proteins c-myc / Q000235:genetics*; D017422:Sequence Analysis, DNA; D013601:T-Lymphocytes / Q000502:physiology; D014158:Transcription, Genetic; D059467:Transcriptome
chemical_list: D000949:Histocompatibility Antigens Class II; C489428:Myc protein, mouse; D016271:Proto-Oncogene Proteins c-myc; D000076123:DNA (Cytosine-5-)-Methyltransferase 1; D004248:DNA (Cytosine-5-)-Methyltransferases; C000619380:DNMT1 protein, human; C000619381:Dnmt1 protein, mouse