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Haney SL, Upchurch GM, Opavska J, Klinkebiel D, Hlady RA, Roy S, Dutta S, Datta K, Opavsky R. Dnmt3a Is a Haploinsufficient Tumor Suppressor in CD8+ Peripheral T Cell Lymphoma. PLoS Genet 2016; 12:e1006334. [PMID: 27690235 PMCID: PMC5045215 DOI: 10.1371/journal.pgen.1006334] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 08/31/2016] [Indexed: 12/29/2022] Open
Abstract
DNA methyltransferase 3A (DNMT3A) is an enzyme involved in DNA methylation that is frequently mutated in human hematologic malignancies. We have previously shown that inactivation of Dnmt3a in hematopoietic cells results in chronic lymphocytic leukemia in mice. Here we show that 12% of Dnmt3a-deficient mice develop CD8+ mature peripheral T cell lymphomas (PTCL) and 29% of mice are affected by both diseases. 10% of Dnmt3a+/- mice develop lymphomas, suggesting that Dnmt3a is a haploinsufficient tumor suppressor in PTCL. DNA methylation was deregulated genome-wide with 10-fold more hypo- than hypermethylated promoters and enhancers, demonstrating that hypomethylation is a major event in the development of PTCL. Hypomethylated promoters were enriched for binding sites of transcription factors AML1, NF-κB and OCT1, implying the transcription factors potential involvement in Dnmt3a-associated methylation. Whereas 71 hypomethylated genes showed an increased expression in PTCL, only 3 hypermethylated genes were silenced, suggesting that cancer-specific hypomethylation has broader effects on the transcriptome of cancer cells than hypermethylation. Interestingly, transcriptomes of Dnmt3a+/- and Dnmt3aΔ/Δ lymphomas were largely conserved and significantly overlapped with those of human tumors. Importantly, we observed downregulation of tumor suppressor p53 in Dnmt3a+/- and Dnmt3aΔ/Δ lymphomas as well as in pre-tumor thymocytes from 9 months old but not 6 weeks old Dnmt3a+/- tumor-free mice, suggesting that p53 downregulation is chronologically an intermediate event in tumorigenesis. Decrease in p53 is likely an important event in tumorigenesis because its overexpression inhibited proliferation in mouse PTCL cell lines, suggesting that low levels of p53 are important for tumor maintenance. Altogether, our data link the haploinsufficient tumor suppressor function of Dnmt3a in the prevention of mouse mature CD8+ PTCL indirectly to a bona fide tumor suppressor of T cell malignancies p53. Global deregulation of cytosine methylation is an epigenetic hallmark of hematologic malignancies that may promote tumorigenesis by silencing tumor suppressor genes, upregulating oncogenes, and inducing genomic instability. DNA methyltransferase 3a (DNMT3A) is one of the three catalytically active enzymes responsible for cytosine methylation and one of the most frequently mutated genes in myeloid and T cell malignancies. Its role in malignant hematopoiesis, however, remains poorly understood. Here we show that Dnmt3a is a haploinsufficient tumor suppressor in the prevention of peripheral T cell lymphomas in mice. Our molecular studies identified a large number of genes deregulated in the absence of Dnmt3a that may be putative drivers of oncogenesis. We also show that downregulation of the tumor suppressor p53 is an important event in the development of mouse T cell lymphomas. Thus, this study establishes a novel mouse model to elucidate how epigenetic deregulation of transcription contributes to the pathogenesis of T cell lymphomas.
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Affiliation(s)
- Staci L. Haney
- Department of Genetics, Cell Biology, and Anatomy, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - G. Michael Upchurch
- Eppley Institute for Research in Cancer and Allied Diseases, Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Jana Opavska
- Eppley Institute for Research in Cancer and Allied Diseases, Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - David Klinkebiel
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Ryan A. Hlady
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Sohini Roy
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Samikshan Dutta
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Kaustubh Datta
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Rene Opavsky
- Department of Genetics, Cell Biology, and Anatomy, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
- Eppley Institute for Research in Cancer and Allied Diseases, Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
- Center for Leukemia and Lymphoma Research, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
- * E-mail:
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Perugini M, Kok CH, Brown AL, Wilkinson CR, Salerno DG, Young SM, Diakiw SM, Lewis ID, Gonda TJ, D'Andrea RJ. Repression of Gadd45α by activated FLT3 and GM-CSF receptor mutants contributes to growth, survival and blocked differentiation. Leukemia 2009; 23:729-38. [DOI: 10.1038/leu.2008.349] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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