DNA Methyltransferase 1 and DNA Methylation Patterning Contribute to Germinal Center B-Cell Differentiation
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
SUBMITTER: Rita Shaknovich
PROVIDER: E-GEOD-31671 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
Similar Datasets
Project description:We performed DNA methylation (HELP) and gene expression profiling in 69 samples of diffuse large B cell lymphoma (DLBCL). First, by gene expression, two molecular subtypes of DLBCL termed as germinal center B cell-like (GCB) and activated B cell-like (ABC) DLBCL were assigned to the 69 DLBCL cases. Then, we performed supervised analysis using HELP data and defined DNA methylation signature differentiating 2 subgroups of DLBCLs. Keywords: DNA methylation profiling The retrospective study included DNA extracted from 69 clinical samples. [This Series represents the DNA methylation profiling component of the study.]
2010-09-03 | E-GEOD-23967 | biostudies-arrayexpress
Project description:The molecular heterogeneity of acute leukemias and other tumors constitutes a major obstacle towards understanding disease pathogenesis and developing new targeted-therapies. Aberrant gene regulation is a hallmark of cancer and plays a central role in determining tumor phenotype. We predicted that integration of different genome-wide epigenetic regulatory marks along with gene expression levels would provide greater power in capturing biological differences between leukemia subtypes. Gene expression, cytosine methylation and histone H3 lysine 9 (H3K9) acetylation were measured using high-density oligonucleotide microarrays in primary human acute myeloid leukemia (AML) and acute lymphocytic leukemia (ALL) specimens. We found that DNA methylation and H3K9 acetylation distinguished these leukemias of distinct cell lineage, as expected, but that an integrative analysis combining the information from each platform revealed hundreds of additional differentially expressed genes that were missed by gene expression arrays alone. This integrated analysis also enhanced the detection and statistical significance of biological pathways dysregulated in AML and ALL. Integrative epigenomic studies are thus feasible using clinical samples and provide superior detection of aberrant transcriptional programming than single-platform microarray studies. Keywords: DNA methylation by HELP 5 acute leukemia samples (2 ALL and 3 AML) in triplicate. Replicate #3 from sample ALL2 was discarded due to bad hybridization quality. No dye swap was performed.
2008-04-01 | E-GEOD-10894 | biostudies-arrayexpress
Project description:MLL-r infant acute lymphoblastic leukemia (ALL) has largely unclear oncogenesis. It has been shown unrelated to copy number change or mutations in the tyrosine kinome. We therefore, explored the possible role of genome wide CpG island hypermethylation in MLL-r infant ALL. We employed the HpaII-tiny fragment Enrichment by Ligation-mediated PCR (HELP) assay to examine MLL-r infant leukemia samples (n=5), other common childhood ALL (n=5) and normals (n=5). We then investigated biological correlation and the therapeutic potential of 5-aza-2’-deoxycytidine (decitabine). Analysis of the HELP assay showed both tight clustering of samples into their biological groups and that MLL-r infant leukemia was globally and comparatively hypermethylated. Further, a majority of genes chosen for analysis from the HELP assay were silenced or under-expressed. MLL-r cell lines showed dose and time-dependent cell kill when treated with decitabine and most down-regulated genes showed increase in expression. This was not seen in the MLL-wt cell line. For the re-expressed genes, methylation specific PCR confirmed preferential promoter methylation in MLL-r samples. Together, this suggests that methylation signatures are unique in pediatric ALL, that promoter hypermethylation may play a significant role in MLL-r infant leukemogenesis, that this can be reversed and demethylating agents may be a potential new therapeutic option in infant leukemia. Keywords: DNA methylation profiling Direct comparison of DNA methylation in leukemic blasts from 5 infants with MLL-r ALL with 5 children with other common types of ALL and 5 normal samples consisting of CD34+ selected cord blood cells (n=3) and CD19+ selected cord blood cells (n=2)
2009-12-29 | E-GEOD-19671 | biostudies-arrayexpress
Project description:We hypothesized that DNA methylation distributes into specific patterns in cancer cells, which reflect critical biological differences. We therefore examined the methylation profiles of 344 patients with acute myeloid leukemia (AML). Clustering of these patients by methylation data segregated patients into 16 groups. Five of these groups defined new AML subtypes that shared no other known feature. In addition, DNA methylation profiles segregated patients with CEBPA aberrations from other subtypes of leukemia, defined four epigenetically distinct forms of AML with NPM1 mutations, and showed that established AML1-ETO, CBFb-MYH11 and PML-RARA leukemia entities are associated with specific methylation profiles. We report a 15-gene methylation classifier predictive of overall survival in an independent patient cohort (p<0.001, adjusted for known covariates). Keywords: DNA methylation profiling DNA methylation profiling of a cohort of 344 AML patients from Erasmus Medical Center and enrolled in clinical trials from the Dutch-German cooperative group HOVON. Additionally, a control group consisting of 8 CD34+ bone marrow samples from healthy donors was also studied.
2010-01-12 | E-GEOD-18700 | biostudies-arrayexpress
Project description:Acute lymphoblastic leukemia (ALL), the commonest childhood malignancy, is characterized by recurring gross and submicroscopic structural genetic alterations that contribute to leukemogenesis. Disordered epigenetic regulation is a hallmark of many tumors, and while analysis of DNA methylation of limited numbers of genes or ALL samples suggests epigenetic alterations may also be important, a large-scale integrative genome-wide analysis evaluating DNA methylation in ALL has not been performed. Here, we report an integrated epigenomic, transcriptional and genetic analysis of 167 childhood ALL cases, comprising B-progenitor ALL with hyperdiploidy (N=26), ETV6-RUNX1 (N=27), TCF3-PBX1 (N=9), BCR-ABL1 (N=19), rearrangement of MLL (MLLr) (N=20), rearrangement of CRLF2 (N=11, CRLF2r), deletion of ERG (N=11), miscellaneous or normal karyotype (N=14), and T-lineage ALL (N=30), including 4 MLLr cases and 7 cases with early T-cell precursor immunophenotype. Genome-wide profiling of structural DNA alterations was performed for all cases using Affymetrix 500K and SNP 6.0 arrays. Affymetrix U133A gene expression profiling data was available for 154 cases [GEO Series GSE26281]. Genome-wide methylation profiling was performed using the HELP microarray assay, which measures methylation at approximately 50,000 CpGs distributed among 22,722 Refseq promoters. Methylation data was compared to that of normal pro-B (CD34+CD19+sIg-), pre-B (CD34-CD19+sIg-) and mature B (CD34-CD19+sIg+) cells FACS-sorted from bone marrow of 6 healthy individuals. Unsupervised hierarchical clustering of the top 4043 most variable methylation probesets identified 9 B-ALL clusters with significant correlation to specific genetic lesions including ETV6-RUNX1, MLLr, BCR-ABL1, CRLF2r, TCF3-PBX1 and ERG deletion. T-ALLs and hyperdiploid B-ALLs also defined specific DNA methylation clusters. Supervised analysis including limma and ANOVA identified distinct DNA methylation signatures for each subtype. Notably, the strength of these signatures was subtype dependent, with more differentially methylated genes observed in ALL cases with genetic alterations targeting transcriptional regulators (e.g. ETV6-RUNX1 and MLLr) and fewer genes in cases with alterations deregulating cytokine receptor signaling (e.g. CRLF2r). Aberrant DNA methylation affected specific and distinct biological processes in the various leukemia subtypes implicating epigenetic regulation of these pathways in the pathogenesis of these different forms of ALL (e.g. TGFB and TNF in ERG deleted leukemias; telomere and centriole regulation in BCR-ABL1 ALL). Aberrantly methylated genes were also enriched for binding sites of known or suspected oncogenic transcription factors that might represent cooperative influences in establishing the phenotype of the various B-ALL subtypes. Most importantly, an integrated analysis of methylation and gene expression of these ALL subtypes demonstrated striking inversely correlated expression of the corresponding gene transcripts. The methylation signatures of each subtype exhibited only partial overlap with those of normal B cells, indicating that the signatures do not simply reflect stage of lymphoid maturation. In a separate approach, we discovered that 81 genes showed consistent aberrant methylation across all ALL subtypes, including the tumor suppressor PDZD2, HOXA5, HOXA6 and MSH2. Inverse correlation with expression was confirmed in 66% of these genes. These data suggest the existence of a common epigenetic pathway underlying the malignant transformation of lymphoid precursor cells. Integrative genetic and epigenetic analysis revealed hypermethylation of genes on trisomic chromosomes that do not show increased expression, suggesting that epigenetic silencing may control genes within amplified regions and explain why only selected genes are overexpressed. Finally, analysis of individual genes targeted by recurring copy number alterations in ALL revealed a subset of genes also targeted by abnormal methylation, with corresponding changes in gene expression (e.g. ERG, GAB1), suggesting that such genes are inactivated far more frequently than suggested by genetic analyses alone. Collectively, the data support a key role of epigenetic gene regulation in the pathogenesis of ALL, and point towards a scenario where genetic and epigenetic lesions cooperatively determine disease phenotype. 186 samples were analyzed by DNA methylation on the HELP array, including 167 Diagnostic ALL samples and 19 Normal Bone Marrow B cells. There are no replicates
2013-06-27 | E-GEOD-38295 | biostudies-arrayexpress
Project description:The normal aging process is a complex phenomenon associated with physiological alterations in the function of cells and organs over time. Although an attractive candidate for mediating transcriptional dysregulation, the contribution of epigenetic dysregulation to these progressive changes in cellular function remains unclear. In this study, we employed the genome-wide HELP assay to define patterns of cytosine methylation throughout the rat genome, and the LUMA assay to measure global levels of DNA methylation in the same samples. We studied both liver and visceral adipose tissue, and demonstrated significant differences in DNA methylation with age at >5% of sites analyzed. Furthermore, we showed that epigenetic dysregulation with age is a highly tissue-dependent phenomenon. The most distinctive loci were located at intergenic sequences and conserved non-coding elements, and not at promoters nor at CG-dinucleotide dense loci. Finally, we demonstrated that changes in methylation occur consistently near genes that are involved in metabolism and metabolic regulation, implicating their potential role in the pathogenesis of age-related diseases. We conclude that different patterns of epigenetic dysregulation occur in each tissue over time and may cause some of the physiological changes associated with normal aging. Direct comparison of DNA methylation in 18 samples belonging to four groups: young liver (n=6), young adipose tissue (n=4), old liver (n=5), old adipose tissue (n=3), isolated from F344*BN rats (young at ~3 months, old at ~18 months). Each microarray consists of a two-color comparison of a methylation-sensitive representation of the genome (HpaII) with an internal methylation-insensitive control/reference (MspI).
2010-05-01 | E-GEOD-17332 | biostudies-arrayexpress
Project description:Acute lymphoblastic leukemia (ALL), the commonest childhood malignancy, is characterized by recurring gross and submicroscopic structural genetic alterations that contribute to leukemogenesis. Disordered epigenetic regulation is a hallmark of many tumors, and while analysis of DNA methylation of limited numbers of genes or ALL samples suggests epigenetic alterations may also be important, a large-scale integrative genome-wide analysis evaluating DNA methylation in ALL has not been performed. Here, we report an integrated epigenomic, transcriptional and genetic analysis of 167 childhood ALL cases, comprising B-progenitor ALL with hyperdiploidy (N=26), ETV6-RUNX1 (N=27), TCF3-PBX1 (N=9), BCR-ABL1 (N=19), rearrangement of MLL (MLLr) (N=20), rearrangement of CRLF2 (N=11, CRLF2r), deletion of ERG (N=11), miscellaneous or normal karyotype (N=14), and T-lineage ALL (N=30), including 4 MLLr cases and 7 cases with early T-cell precursor immunophenotype. Genome-wide profiling of structural DNA alterations was performed for all cases using Affymetrix 500K and SNP 6.0 arrays. Affymetrix U133A gene expression profiling data was available for 154 cases. Genome-wide methylation profiling was performed using the HELP microarray assay, which measures methylation at approximately 50,000 CpGs distributed among 22,722 Refseq promoters. Methylation data was compared to that of normal pro-B (CD34+CD19+sIg-), pre-B (CD34-CD19+sIg-) and mature B (CD34-CD19+sIg+) cells FACS-sorted from bone marrow of 6 healthy individuals. Unsupervised hierarchical clustering of the top 4043 most variable methylation probesets identified 9 B-ALL clusters with significant correlation to specific genetic lesions including ETV6-RUNX1, MLLr, BCR-ABL1, CRLF2r, TCF3-PBX1 and ERG deletion. T-ALLs and hyperdiploid B-ALLs also defined specific DNA methylation clusters. Supervised analysis including limma and ANOVA identified distinct DNA methylation signatures for each subtype. Notably, the strength of these signatures was subtype dependent, with more differentially methylated genes observed in ALL cases with genetic alterations targeting transcriptional regulators (e.g. ETV6-RUNX1 and MLLr) and fewer genes in cases with alterations deregulating cytokine receptor signaling (e.g. CRLF2r). Aberrant DNA methylation affected specific and distinct biological processes in the various leukemia subtypes implicating epigenetic regulation of these pathways in the pathogenesis of these different forms of ALL (e.g. TGFB and TNF in ERG deleted leukemias; telomere and centriole regulation in BCR-ABL1 ALL). Aberrantly methylated genes were also enriched for binding sites of known or suspected oncogenic transcription factors that might represent cooperative influences in establishing the phenotype of the various B-ALL subtypes. Most importantly, an integrated analysis of methylation and gene expression of these ALL subtypes demonstrated striking inversely correlated expression of the corresponding gene transcripts. The methylation signatures of each subtype exhibited only partial overlap with those of normal B cells, indicating that the signatures do not simply reflect stage of lymphoid maturation. In a separate approach, we discovered that 81 genes showed consistent aberrant methylation across all ALL subtypes, including the tumor suppressor PDZD2, HOXA5, HOXA6 and MSH2. Inverse correlation with expression was confirmed in 66% of these genes. These data suggest the existence of a common epigenetic pathway underlying the malignant transformation of lymphoid precursor cells. Integrative genetic and epigenetic analysis revealed hypermethylation of genes on trisomic chromosomes that do not show increased expression, suggesting that epigenetic silencing may control genes within amplified regions and explain why only selected genes are overexpressed. Finally, analysis of individual genes targeted by recurring copy number alterations in ALL revealed a subset of genes also targeted by abnormal methylation, with corresponding changes in gene expression (e.g. ERG, GAB1), suggesting that such genes are inactivated far more frequently than suggested by genetic analyses alone. Collectively, the data support a key role of epigenetic gene regulation in the pathogenesis of ALL, and point towards a scenario where genetic and epigenetic lesions cooperatively determine disease phenotype. 194 samples were analyzed by DNA methylation on the HELP array, including 167 Diagnostic ALL samples, 19 Normal Bone Marrow B cell samples, and 8 Normal T lymphocyte cell samples. There are no replicates.
2013-06-27 | E-GEOD-44860 | biostudies-arrayexpress
Project description:Acute megakaryoblastic leukemia (AMKL) is more frequently seen in Down syndrome patients, where it is often preceded by a transient myeloproliferative disorder (DS-TMD). The development of DS-TMD and DS-AMKL require not only the presence of the trisomy 21 but also that of GATA1 mutations. However, despite extensive studies into the genetics of DS-AMKL, not much is known about the epigenetic deregulation associated with this disease. In order to understand how epigenetic changes at the DNA methylation level contribute to DS leukemogenesis we performed DNA methylation profiling at different stages of development of this disease and analyzed the dynamics of epigenetic reprogramming. Early genome-wide epigenetic changes can be detected in trisomy 21 fetal liver mononuclear cells, even prior to the development of hematological abnormalities. These early changes are characterized by marked loss of DNA methylation at genes associated with regulation of key developmental processes. This first wave of aberrant DNA hypomethylation is followed by a second wave of epigenetic reprogramming detected in blast cells from DS-TMD and DS-AMKL, characterized by gains of methylation. This second wave of hypermethylation targets a distinct set of genes, preferentially affecting genes involved in hematopoiesis and regulation of cell growth and proliferation. DNA methylation profiles obtained at different stages of the development of Down syndrome AMKL and from CD41+ cells from partial trisomic mice
2013-08-19 | E-GEOD-46167 | biostudies-arrayexpress
Project description:Mantle Cell Lymphoma (MCL) is a mostly incurable malignancy arising from naïve B cells (NBC) in the mantle zone of lymph node follicles. We analyzed genome-wide methylation in MCL patients using the HELP (Hpa II tiny fragment Enrichment by Ligation mediated PCR) assay and found significant aberrancy in promoter methylation patterns as compared to normal NBCs. Using biological and stringent statistical criteria, we further identified four hypermethylated genes CDKN2B, MLF-1, PCDH8, HOXD8 and four hypomethylated genes CD37, HDAC1, NOTCH1 and CDK5 where aberrant methylation was associated with inverse changes in mRNA levels. MassArray Epityper analysis confirmed the presence of differential methylation at the promoter region of these genes. Immunohistochemical analysis of an independent cohort of 14 MCL patient samples, confirmed CD37 surface expression in 93% of patients, validating its selection as a target for MCL therapy. Treatment of MCL cell lines with a novel small modular immunopharmaceutical(CD37-SMIP) resulted in significant loss of viability in cell lines with intense surface CD37 expression. Treatment of MCL cell lines with the DNA methyltransferase inhibitor decitabine resulted in reversal of aberrant hypermethylation and synergized with the HDAC inhibitor SAHA in induction of the four hypermethylated genes CDKN2B, MLF-1, PCDH8 and HOXD8. The combination of Decitabine and SAHA also resulted in potent and synergistic anti-MCL cytotoxicity as compared to either drug alone. In conclusion, our analysis shows prominent and aberrant methylation of the MCL genome and identifies novel differentially methylated and expressed genes in MCL cell lines and patient samples. Furthermore, our data suggest that differentially methylated genes can be targeted for therapeutic benefit in MCL. Gene expression profiling by array comprised of 8 mantle cell lymphoma (MCL) cell lines and 8 leukemic blast from blood from patients newly diagnosed with MCL. Unbiased genome-wide analysis of DNA methylation in leukemic blast from peripheral blood or pheresis products from 22 patients newly diagnosed with mantle cell lymphoma (MCL) prior to any treatment. 10 IgD+ Na ve B cells from specimens from healthy donors undergoing routine tonsillectomy were used as appropriate controls. Methylation patterns of 13 MCL cell lines were also compared.
2010-07-30 | E-GEOD-19243 | biostudies-arrayexpress
Project description:Cancer cells have an altered distribution of DNA methylation and express aberrant DNA methyltransferase 3B transcripts, which encode truncated proteins. To test if a truncated DNMT3B isoform disrupts DNA methylation in vivo, we constructed transgenic mice expressing DNMT3B7, a common truncated DNMT3B isoform in cancer cells. DNMT3B7 transgenic mice exhibit altered embryonic development, including lymphopenia, craniofacial abnormalities, and cardiac defects, similar to Dnmt3b-deficient animals, but rarely develop cancer. However, DNMT3B7 expression increases the frequency of mediastinal lymphomas in Eμ−myc animals. Eμ-myc/DNMT3B7 lymphomas have more chromosomal rearrangements, increased global methylation levels, and more locus-specific perturbations in DNA methylation patterns compared to Eμ-myc lymphomas. Our results demonstrate that a truncated DNMT3B protein can alter tumorigenesis, suggesting a similar role in human tumors. Direct comparison of DNA methylation in lymphoma samples from Eu-Myc vs Eu-Myc/Dnmt3b7 mice.
2010-07-30 | E-GEOD-21273 | biostudies-arrayexpress