Ontology highlight
ABSTRACT:
PROVIDER: PRJNA816342 | ENA |
REPOSITORIES: ENA
Similar Datasets
Project description:Igh/Myc translocations underlie both sporadic Burkitt lymphoma (BL) and the endemic clinical form affecting African children infected with malaria. However, while sporadic translocations decapitate Myc from 5' proximal regulatory elements, most endemic events occur hundreds of kilobases away from Myc. The origin of these rearrangements and how they deregulate oncogenes at such distances remain unclear. Here we recapitulate endemic BL-like translocations in plasmacytomas from uracil N-glycosylase (UNG) deficient mice. We demonstrate that in these animals, rare endemic-like translocations arise from non-targeted DNA breaks at Myc loci. Deep-sequencing analyses revealed that the deregulated 3' Igh enhancer alpha physically interacts with and remodels 0.45Mb of translocated chromatin. The results thus explain the long-range deregulation of oncogenes in human and mouse B cell tumors. ChIP-Seq, 4C, and 1 RNASeq samples used to characterize mouse plasmacytoma cell lines and in vitro activated mouse B cells. Biological replicates are present for many of the samples.
2013-07-04 | E-GEOD-48514 | biostudies-arrayexpress
Project description:Epidemiological data have suggested that African Americans (AA) are twice as likely to be diagnosed with multiple myeloma (MM) as compared to European Americans (EA). Here, we have analyzed a set of cytogenetic and genomic data derived from AA and EA MM patients. We have compared the frequency of IgH translocations in a series of data from 115 AA patients from three studies and EA patients from the Eastern Cooperative Oncology Group (ECOG) studies E4A03 and E9487. We have also interrogated tumors from 45 AA and 196 EA MM patients for somatic copy number abnormalities associated with poor outcome. In addition, 35 AA and 178 EA patients were investigated for a transcriptional profile associated with high-risk disease. Overall, based on this cohort, genetic profiles were similar except for a significantly lower frequency of IgH translocations (40% vs. 52%; p=0.032) in AA patients. Frequency differences of somatic copy number aberrations were not significant after correction for multiple testing. There was also no significant difference in the frequency of high-risk disease based upon gene expression profiling. Our study represents the first comprehensive comparisons of the frequency and distribution of molecular alterations in MM tumors between AA and EA patients. This submission contains 27 of the 45 African American cases analyzed by aCGH. In addition, 196 samples from European American myeloma patients were also analyzed and compared to the 45 African American patients.
2013-02-25 | E-GEOD-44271 | biostudies-arrayexpress
Project description:Epidemiological data have suggested that African Americans (AA) are twice as likely to be diagnosed with multiple myeloma (MM) as compared to European Americans (EA). Here, we have analyzed a set of cytogenetic and genomic data derived from AA and EA MM patients. We have compared the frequency of IgH translocations in a series of data from 115 AA patients from three studies and EA patients from the Eastern Cooperative Oncology Group (ECOG) studies E4A03 and E9487. We have also interrogated tumors from 45 AA and 196 EA MM patients for somatic copy number abnormalities associated with poor outcome. In addition, 35 AA and 178 EA patients were investigated for a transcriptional profile associated with high-risk disease. Overall, based on this cohort, genetic profiles were similar except for a significantly lower frequency of IgH translocations (40% vs. 52%; p=0.032) in AA patients. Frequency differences of somatic copy number aberrations were not significant after correction for multiple testing. There was also no significant difference in the frequency of high-risk disease based upon gene expression profiling. Our study represents the first comprehensive comparisons of the frequency and distribution of molecular alterations in MM tumors between AA and EA patients.
2013-02-25 | GSE44271 | GEO
Project description:The transcription factor FOXP1 is implicated in the pathogenesis of B-cell lymphomas through immunoglobulin heavy chain (IGH) locus-related chromosomal translocations leading to dysregulated expression of FOXP1. Translocations of FOXP1 with non-IG gene sequences have been also reported, but the molecular consequences of such aberrations remain undetermined. Here, using molecular cytogenetics and molecular biology studies, we comprehensively analyzed four lymphoma cases with non-IG rearrangements of FOXP1 and compared these with cases harboring t(3;14)(p13;q32)/IGH-FOXP1 and FOXP1-expressing lymphomas without underlying t(3p13/FOXP1). We found that non-IG rearrangements are usually acquired during evolution of lymphoma and constantly target the coding region of FOXP1, promiscuously fusing with coding and non-coding gene sequences at various reciprocal breakpoints (2q36, 10q24 and 3q11). Intriguingly, these rearrangements do not generate functional chimeric genes but commonly disrupt the full-length FOXP1 transcript leading to an aberrant expression of N-truncated FOXP1 isoforms, as shown by QRT-PCR and Western blot analysis. In contrast, cases with t(3;14)(p13;q32)/IGH-FOXP1 overexpress the full-length FOXP1. Collectively, our findings point to a dual mechanism through which FOXP1 is implicated in B-cell lymphomagenesis. The primary t(3;14)(p13;q32)/IGH-FOXP1 produces the full-length protein with potent oncogenic activity, whereas the secondary non-IG 17 rearrangements of FOXP1 generate N-truncated FOXP1 isoforms, likely driving progression of disease. Using molecular cytogenetics and molecular biology studies (including RNA-seq), we comprehensively analyzed four lymphoma cases with non-IG rearrangements of FOXP1 and compared these with cases harboring t(3;14)(p13;q32)/IGH-FOXP1 and FOXP1-expressing lymphomas without underlying t(3p13/FOXP1).
2013-09-04 | E-GEOD-50514 | biostudies-arrayexpress
Project description:PURPOSE. The deregulation of CCND1, CCND2 and CCND3 genes represents a common event in multiple myeloma (MM). The recently proposed TC classification grouped MM patients into five classes on the basis of their cyclins D expression profiles and the presence of the main translocations involving the immunoglobulin heavy-chain locus (IGH) at 14q32. In this study, we provide a molecular characterization of the identified TC groups. MATERIALS AND METHODS. The gene expression profiles of purified plasma cells from 50 MM cases were used to stratify the samples into the five TC classes and identify their transcriptional fingerprints. The cyclin D expression data were validated by means of real-time quantitative PCR analysis; fluorescence in-situ hybridization was used to investigate the cyclin D loci arrangements, and to detect the main IGH translocations and the chromosome 13q deletion. RESULTS. Class-prediction analysis identified 112 probe sets as characterizing the TC1, TC2, TC4 and TC5 groups, whereas the TC3 samples showed heterogeneous phenotypes and no marker genes. The TC2 group, which showed extra copies of the CCND1 locus and no IGH translocations or the chromosome 13q deletion, was characterized by the overexpression of genes involved in protein biosynthesis at translational level. A meta-analysis of published datasets validated the identified gene expression signatures. CONCLUSIONS. Our data contribute to the understanding of the molecular and biological features of distinct MM subtypes. The identification of a distinctive gene expression pattern in TC2 patients may improve risk stratification and indicate novel therapeutic targets. Experiment Overall Design: This series of microarray experiments contains the gene expression profiles of purified plasma cells (PCs) obtained from 50 newly diagnosed multiple myeloma (MM). PCs were purified from bone marrow specimens, after red blood cell lysis with 0.86% ammonium chloride, using CD138 immunomagnetic microbeads. The purity of the positively selected PCs was assessed by morphology and flow cytometry and was > 90% in all cases. 5 micrograms of total RNA was processed and hybridized to the Affymetrix HG-U133A chip following the manufacturer's instructions.
2007-10-27 | E-GEOD-2912 | biostudies-arrayexpress
Project description:High-throughput genome-wide translocation sequencing (HTGTS) is a robust approach to identify genome-wide translocation junctions. We performed HTGTS to study the fate of introduced c-myc DSBs in mouse splenic B cells activated for activation cytidine deaminase (AID)-dependent class switch recombination (CSR). We found frequent translocations of c-myc DSBs to AID-initiated DSBs in IgH switch regions in wild-type (WT) and ATM-deficient B cells. However, c-myc also translocated frequently to newly generated DSBs within a 35-megabase region downstream of IgH in ATM-deficient, but not WT, CSR-activated B cells. Moreover, we found such DSBs and translocations in activated B cells that did not express AID or undergo CSR. These findings indicate that ATM deficiency leads to formation of chromosome 12 dicentrics via RAG-initiated IgH DSBs in progenitor B cells and that these dicentrics can be propagated developmentally into mature B cells where they generate new DSBs downstream of IgH via breakage-fusion-bridge cycles. Preparation of libraries from WT or ATM-deficient activated by a-CD40/IL4 or RP105.
2014-06-18 | E-GEOD-58599 | biostudies-arrayexpress
Project description:Igh/Myc translocations underlie both sporadic Burkitt lymphoma (BL) and the endemic clinical form affecting African children infected with malaria. However, while sporadic translocations decapitate Myc from 5' proximal regulatory elements, most endemic events occur hundreds of kilobases away from Myc. The origin of these rearrangements and how they deregulate oncogenes at such distances remain unclear. Here we recapitulate endemic BL-like translocations in plasmacytomas from uracil N-glycosylase (UNG) deficient mice. We demonstrate that in these animals, rare endemic-like translocations arise from non-targeted DNA breaks at Myc loci. Deep-sequencing analyses revealed that the deregulated 3' Igh enhancer alpha physically interacts with and remodels 0.45Mb of translocated chromatin. The results thus explain the long-range deregulation of oncogenes in human and mouse B cell tumors.
2013-07-04 | GSE48514 | GEO
Project description:PURPOSE. The deregulation of CCND1, CCND2 and CCND3 genes represents a common event in multiple myeloma (MM). The recently proposed TC classification grouped MM patients into five classes on the basis of their cyclins D expression profiles and the presence of the main translocations involving the immunoglobulin heavy-chain locus (IGH) at 14q32. In this study, we provide a molecular characterization of the identified TC groups. MATERIALS AND METHODS. The gene expression profiles of purified plasma cells from 50 MM cases were used to stratify the samples into the five TC classes and identify their transcriptional fingerprints. The cyclin D expression data were validated by means of real-time quantitative PCR analysis; fluorescence in-situ hybridization was used to investigate the cyclin D loci arrangements, and to detect the main IGH translocations and the chromosome 13q deletion. RESULTS. Class-prediction analysis identified 112 probe sets as characterizing the TC1, TC2, TC4 and TC5 groups, whereas the TC3 samples showed heterogeneous phenotypes and no marker genes. The TC2 group, which showed extra copies of the CCND1 locus and no IGH translocations or the chromosome 13q deletion, was characterized by the overexpression of genes involved in protein biosynthesis at translational level. A meta-analysis of published datasets validated the identified gene expression signatures. CONCLUSIONS. Our data contribute to the understanding of the molecular and biological features of distinct MM subtypes. The identification of a distinctive gene expression pattern in TC2 patients may improve risk stratification and indicate novel therapeutic targets. Keywords: other
2005-09-01 | GSE2912 | GEO
Project description:High-throughput genome-wide translocation sequencing (HTGTS) is a robust approach to identify genome-wide translocation junctions. We performed HTGTS to study the fate of introduced c-myc DSBs in mouse splenic B cells activated for activation cytidine deaminase (AID)-dependent class switch recombination (CSR). We found frequent translocations of c-myc DSBs to AID-initiated DSBs in IgH switch regions in wild-type (WT) and ATM-deficient B cells. However, c-myc also translocated frequently to newly generated DSBs within a 35-megabase region downstream of IgH in ATM-deficient, but not WT, CSR-activated B cells. Moreover, we found such DSBs and translocations in activated B cells that did not express AID or undergo CSR. These findings indicate that ATM deficiency leads to formation of chromosome 12 dicentrics via RAG-initiated IgH DSBs in progenitor B cells and that these dicentrics can be propagated developmentally into mature B cells where they generate new DSBs downstream of IgH via breakage-fusion-bridge cycles.
2014-06-18 | GSE58599 | GEO
Project description:B-cell development is spatially and temporally regulated with the Ig heavy chain (IgH) locus as a conductor. Starting with the first steps of B-cell development, IgH DNA remodeling constantly occurs under the control of several cis-regulatory elements scattered all along the IgH locus. Their individual genomic deletion had partial or no effect on B-cell development. In this study we investigate the effect of the dual deletion of 5’Eµ and 3’RR enhancer on IgH transcription. Numerous B-cell lymphomas feature translocations linking oncogenes with the IgH locus and epigenetic drugs such as histone deacetylase inhibitors (HDACi) have been approved to treat some of them. In this study we investigated IgH locus transcription in B-cell splenocytes stimùulated with LPS and the HDACi SAHA.
2021-03-27 | GSE169691 | GEO