DNMT3B overexpression contributes to aberrant DNA methylation and MYC-driven tumor maintenance in T-ALL and Burkitt’s lymphoma
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE101907 | GEO | 2017/07/27
SECONDARY ACCESSION(S): PRJNA395905
REPOSITORIES: GEO
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Project description:Aberrant DNA methylation is a hallmark of cancer. However, our understanding of how tumor cell-specific DNA methylation patterns are established and maintained is limited. Here, we report that in T-cell acute lymphoblastic leukemia (T-ALL) and Burkitt's lymphoma the MYC oncogene causes overexpression of DNA methyltransferase (DNMT) 1 and 3B, which contributes to tumor maintenance. By utilizing a tetracycline-regulated MYC transgene in a mouse T-ALL (EμSRα-tTA;tet-o-MYC) and human Burkitt's lymphoma (P493-6) model, we demonstrated that DNMT1 and DNMT3B expression depend on high MYC levels, and that their transcription decreased upon MYC-inactivation. Chromatin immunoprecipitation indicated that MYC binds to the DNMT1 and DNMT3B promoters, implicating a direct transcriptional regulation. Hence, shRNA-mediated knock-down of endogenous MYC in human T-ALL and Burkitt's lymphoma cell lines downregulated DNMT3B expression. Knock-down and pharmacologic inhibition of DNMT3B in T-ALL reduced cell proliferation associated with genome-wide changes in DNA methylation, indicating a tumor promoter function during tumor maintenance. We provide novel evidence that MYC directly deregulates the expression of both de novo and maintenance DNMTs, showing that MYC controls DNA methylation in a genome-wide fashion. Our finding that a coordinated interplay between the components of the DNA methylating machinery contributes to MYC-driven tumor maintenance highlights the potential of specific DNMTs for targeted therapies.
| S-EPMC5652751 | biostudies-literature
Project description:We quantified the targets and kinetics of DNA methylation acquisition in mouse embryos, and determined the contribution of the de novo methyltransferases DNMT3A and DNMT3B to this process. We provide single-base maps of cytosine methylation by RRBS from the blastocysts to post-implantation stages and in embryos lacking DNMT3A or DNMT3B activity, and performed RNA-Seq in embryos lacking DNMT3B activity. We sequenced RRBS libraries prepared from genomic DNA isolated from embryos at consecutive stages of development between E3.5 and E11.5,and adult differentiated cells (sperm, liver). We performed RRBS on blastocysts at E3.5/E4.5, dissected epiblasts at E5.5/E6.5/E7/5, whole embryos at E8.5/E10.5 and limbs at E11.5. RRBS experiments in Dnmt3a-/- and Dnmt3b-/- embryos were performed in biological duplicates on individual embryos. We sequenced RNA-Seq libraries prepared from total RNAs of three WT and Dnmt3b-/- littermate embryos collected at E8.5.
2014-11-14 | E-GEOD-60334 | biostudies-arrayexpress
Project description:The methylation status of colon epithelial cells was profiled in wild type mice and mice expressing a Dnmt3b transgene. Genome-scale methylation profiles were generated using reduced representation bisulfite sequencing (RRBS), with CpG methylation scored by promoter and also summarized by gene. Dnmt3b expression is associated with a strong increase in de novo methylation of a discrete subset of "methylation sensitive" genes which show a strong concordance with genes methylated in human colon cancer. These results, together with further analysis, indicate that colon epithelial cell methylation in the Dnmt3b mouse model predicts DNA methylation of human colon cancer with high confidence. Three each of Dnmt3b-induced and control mice, each split into two fractions.
2011-10-25 | E-GEOD-26758 | biostudies-arrayexpress
Project description:In adult cancers, epigenetic changes and aberrant splicing of the DNMT3B is commonly observed, and the pattern of gene methylation and expression has been shown to be modified by DNMT3B7, a truncated protein of DNMT3B. Much less is known about the mechanism of epigenetic changes in the pediatric cancer neuroblastoma. To investigate if aberrant DNMT3B transcripts alter DNA methylation, gene expression and tumor phenotype in neuroblastoma, we measured DNMT3B isoform expression in primary tumors and cell lines. Higher levels of DNMT3B7 were detected in differentiated ganglioneuroblastomas compared to undifferentiated neuroblastomas, suggesting that expression of DNMT3B7 may induce a less clinically aggressive tumor phenotype. To test this hypothesis, we investigated the effects of forced DNMT3B7 in neuroblastoma cells. We found that DNMT3B7 expression significantly inhibited neuroblastoma cell proliferation in vitro, and in neuroblastoma xenografts, DNMT3B7 decreased angiogenesis and tumor growth. DNMT3B7-positive cells had higher levels of total genomic methylation, and RNA-sequencing revealed a dramatic decrease in expression of FOS and JUN family members, AP1 complex components. Consistent with the established antagonistic relationship between AP1 expression and retinoic acid receptor activity, decreased proliferation and increased differentiation was seen in the DNMT3B7-expressing neuroblastoma cells following treatment with all trans retinoic acid (ATRA) compared to controls. Our results demonstrate that high levels of DNMT3B7 modify the epigenome in neuroblastoma cells, induce changes in gene expression, inhibit tumor growth, and increase sensitivity to ATRA. Further knowledge regarding mechanisms by which DNMT3B7 regulates gene methylation may ultimately lead to the development of therapeutic strategies that reverse the epigenetic aberrations that drive neuroblastoma pathogenesis. DNMT3B7, a truncated DNMT3B isoform, was stably transfected into an N-type neuroblastoma cell line (LA1-55n) using a Tet-off inducible system. DNMT3B7 expressing cells were compared to vector control cells after 21 days of induction.
2012-10-05 | E-GEOD-36350 | biostudies-arrayexpress
Project description:The methylation status of colon epithelial cells was profiled in wild type mice and mice expressing a Dnmt3b transgene. Genome-scale methylation profiles were generated using reduced representation bisulfite sequencing (RRBS), with CpG methylation scored by promoter and also summarized by gene. Dnmt3b expression is associated with a strong increase in de novo methylation of a discrete subset of "methylation sensitive" genes which show a strong concordance with genes methylated in human colon cancer. These results, together with further analysis, indicate that colon epithelial cell methylation in the Dnmt3b mouse model predicts DNA methylation of human colon cancer with high confidence.
2011-10-26 | GSE26758 | GEO
Project description:We quantified the targets and kinetics of DNA methylation acquisition in mouse embryos, and determined the contribution of the de novo methyltransferases DNMT3A and DNMT3B to this process. We provide single-base maps of cytosine methylation by RRBS from the blastocysts to post-implantation stages and in embryos lacking DNMT3A or DNMT3B activity, and performed RNA-Seq in embryos lacking DNMT3B activity.
2014-11-14 | GSE60334 | GEO
Project description:Aberrant DNA methylation is a hallmark of cancer but mechanisms contributing to the abnormality remain elusive. Here, we report that most of lung cancer cell lines tested expressed predominantly ∆DNMT3B-del whereas normal bronchial epithelial cells expressed equal quantities of ∆DNMT3B and ∆DNMT3B-del. We demonstrate biological impacts of ∆DNMT3B4-del, a ∆DNMT3B-del isoform, in a transgenic mouse model. Expression of ∆DNMT3B4-del in the mouse lungs resulted in an increased global DNA hypomethylation, focal DNA hypermethylation, epithelial hyperplastia and tumor formation when challenged with a tobacco carcinogen. In patients with non-small cell lung cancer, 83% of the primary tumors expressed predominantly ∆DNMT3B-del. Our results demonstrate ∆DNMT3B4-del as a critical factor in developing aberrant DNA methylation during lung tumorigenesis.
2017-02-09 | GSE68922 | GEO
Project description:DNA methylation has suppressive effects on gene transcription and it is involved in a variety of physiologic processes, including development and cancer. As we and others demonstrated, Dnmt3b is a tumor suppressor in oncogene-driven lymphoid and myeloid malignancies in mice. Due to numerous activities such as methylation-dependent and independent repression and accessory functions, it is difficult to pinpoint physiological processes solely dependent on catalytic activity of Dnmt3b. By utilizing our new mouse model expressing catalytically inactive Dnmt3b at physiological levels we identified genome-wide methylation changes and aberrant gene expression profiles that are specific to catalytic activity of DNMT3b.
2020-12-30 | GSE154451 | GEO
Project description:In adult cancers, epigenetic changes and aberrant splicing of the DNMT3B is commonly observed, and the pattern of gene methylation and expression has been shown to be modified by DNMT3B7, a truncated protein of DNMT3B. Much less is known about the mechanism of epigenetic changes in the pediatric cancer neuroblastoma. To investigate if aberrant DNMT3B transcripts alter DNA methylation, gene expression and tumor phenotype in neuroblastoma, we measured DNMT3B isoform expression in primary tumors and cell lines. Higher levels of DNMT3B7 were detected in differentiated ganglioneuroblastomas compared to undifferentiated neuroblastomas, suggesting that expression of DNMT3B7 may induce a less clinically aggressive tumor phenotype. To test this hypothesis, we investigated the effects of forced DNMT3B7 in neuroblastoma cells. We found that DNMT3B7 expression significantly inhibited neuroblastoma cell proliferation in vitro, and in neuroblastoma xenografts, DNMT3B7 decreased angiogenesis and tumor growth. DNMT3B7-positive cells had higher levels of total genomic methylation, and RNA-sequencing revealed a dramatic decrease in expression of FOS and JUN family members, AP1 complex components. Consistent with the established antagonistic relationship between AP1 expression and retinoic acid receptor activity, decreased proliferation and increased differentiation was seen in the DNMT3B7-expressing neuroblastoma cells following treatment with all trans retinoic acid (ATRA) compared to controls. Our results demonstrate that high levels of DNMT3B7 modify the epigenome in neuroblastoma cells, induce changes in gene expression, inhibit tumor growth, and increase sensitivity to ATRA. Further knowledge regarding mechanisms by which DNMT3B7 regulates gene methylation may ultimately lead to the development of therapeutic strategies that reverse the epigenetic aberrations that drive neuroblastoma pathogenesis.
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Project description:To better characterize the effects of USP7 on DNA methylation, we performed reduced representative bisulfite sequencing (RRBS) analysis for a genome-wide comparison of DNA methylation in wild-type, USP7-KO-1, DNMT3A/3B-DKO and DNMT3A/DNMT3B/USP7-TKO HeLa cell lines. RRBS analysis showed increased DNA methylation in USK7-KO cells and loss of USP7 elevates DNA methylation on pre-existing sites and de novo methylation.
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