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Dnmt3a Is a Haploinsufficient Tumor Suppressor in CD8+ Peripheral T Cell Lymphoma
- Source :
- PLoS Genetics, Vol 12, Iss 9, p e1006334 (2016), PLoS Genetics
- Publication Year :
- 2016
- Publisher :
- Public Library of Science (PLoS), 2016.
-
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.<br />Author Summary 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.
- Subjects :
- 0301 basic medicine
Cancer Research
Physiology
medicine.disease_cause
Biochemistry
Hematologic Cancers and Related Disorders
0302 clinical medicine
Immune Physiology
Cellular types
Cytotoxic T cell
Genetics (clinical)
DNA methylation
Mammalian Genomics
Immune cells
Hematology
Genomics
Animal Models
Methylation
Chromatin
3. Good health
Nucleic acids
medicine.anatomical_structure
Oncology
030220 oncology & carcinogenesis
embryonic structures
White blood cells
Epigenetics
Lymphomas
DNA modification
Chromatin modification
Research Article
Chromosome biology
Cell biology
Blood cells
lcsh:QH426-470
T cell
Immunology
T cells
Cytotoxic T cells
Mouse Models
Biology
Research and Analysis Methods
03 medical and health sciences
Model Organisms
Genetics
medicine
Molecular Biology
Ecology, Evolution, Behavior and Systematics
Medicine and health sciences
Biology and life sciences
Cancers and Neoplasms
Promoter
DNA
medicine.disease
Molecular biology
Peripheral T-cell lymphoma
lcsh:Genetics
030104 developmental biology
Animal cells
Animal Genomics
Gene expression
Carcinogenesis
Spleen
CD8
Subjects
Details
- Language :
- English
- ISSN :
- 15537404 and 15537390
- Volume :
- 12
- Issue :
- 9
- Database :
- OpenAIRE
- Journal :
- PLoS Genetics
- Accession number :
- edsair.doi.dedup.....9c3a36bade663062f23eacf58a18ad00