Frequent mutations of FBXO11 identify BCL6 as a therapeutic target in Burkitt Lymphoma
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PROVIDER: PRJNA668330 | ENA |
REPOSITORIES: ENA
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Project description:BCL6 is a key oncogene in lymphoma pathogenesis. The expression of BCL6 in lymphoid cells can be deregulated by several mechanisms, including chromosomal translocations, somatic mutations in the promoter regulatory regions or reduced proteasome-mediated degradation. FBXO11 was recently identified as a major ubiquitin ligase involved in the degradation of BCL6 and is frequently inactivated in diffuse large B-cell lymphoma (DLBCL). In this work, we found that FBXO11 is frequently mutated in Burkitt lymphoma (BL) but rarely mutated in other BCL6-positive lymphomas, such as follicular lymphoma (FL). All mutations tested impaired FBXO11 mediated BCL6 degradation and FBXO11 knock-out completely stabilized BCL6 levels in human BL cell lines. Conditional deletion of one copy or both copies of FBXO11 in c-Myc-driven B cell lymphoma in mice accelerated lymphomagenesis, genetically confirming that FBXO11 is a haplo-insufficient oncosuppressor in lymphoma. In both FBOX11 WT and deficient BL mouse and human cell lines, blockade of BCL6 via a specific degrader or BCL6 inhibitors, impaired lymphoma growth in vitro and in vivo, an effect further enhanced by co-inhibition of c-Myc activity. Overall these findings not only establish FBXO11 as one of the most frequently mutated genes in BL, but also elucidate its biological functions in lymphomagenesis and thereby identify BCL6 as a specific therapeutic target in BL.
2021-12-31 | GSE159303 | GEO
Project description:The expression of BCL6 in B-cell lymphoma can be deregulated by chromosomal translocations, somatic mutations in the promoter regulatory regions, or reduced proteasome-mediated degradation. FBXO11 was recently identified as a ubiquitin ligase that is involved in the degradation of BCL6, and it is frequently inactivated in lymphoma or other tumors. Here, we show that FBXO11 mutations are found in 23% of patients with Burkitt lymphoma (BL). FBXO11 mutations impaired BCL6 degradation, and the deletion of FBXO11 protein completely stabilized BCL6 levels in human BL cell lines. Conditional deletion of 1 or 2 copies of the FBXO11 gene in mice cooperated with oncogenic MYC and accelerated B-cell lymphoma onset, providing experimental evidence that FBXO11 is a haploinsufficient oncosuppressor in B-cell lymphoma. In wild-type and FBXO11-deficient BL mouse and human cell lines, targeting BCL6 via specific degraders or inhibitors partially impaired lymphoma growth in vitro and in vivo. Inhibition of MYC by the Omomyc mini-protein blocked cell proliferation and increased apoptosis, effects further increased by combined BCL6 targeting. Thus, by validating the functional role of FBXO11 mutations in BL, we further highlight the key role of BCL6 in BL biology and provide evidence that innovative therapeutic approaches, such as BCL6 degraders and direct MYC inhibition, could be exploited as a targeted therapy for BL.
| S-EPMC9153037 | biostudies-literature
Project description:MYC translocations are the biologic hallmark of Burkitt lymphomas but also occur in other mature B-cell lymphomas. If accompanied by chromosomal breaks targeting the BCL2 and/or BCL6 oncogenes, these MYC translocation-positive (MYC+) lymphomas are called double-hit lymphomas (DHLs); otherwise, the term single-hit lymphoma (SHL) is applied. In order to characterize the biologic features of these MYC+ lymphomas other than Burkitt lymphomas, we explored, after exclusion of molecular Burkitt lymphoma (mBL) as defined by gene expression profiling (GEP), the molecular, pathological and clinical aspects of 80 MYC translocation (MYC+) lymphomas (31 SHL, 26 BCL2+/MYC+, 14 BCL6+/MYC+, 6 BCL2+/BCL6+/MYC+ and 3 MYC+ lymphomas with unknown BCL6 status). Comparison of SHL and DHL revealed no difference in frequency of MYC partner (IG/non-IG), genomic complexity or MYC expression and no differences in GEP. DHL showed a more frequent GCB-like GEP and higher IGH and MYC mutation rates. GEP revealed 130 differentially expressed genes between BCL6+/MYC+ and BCL2+/MYC+ DHL. BCL2+/MYC+ DHL showed a more frequent GCB-like GEP. Analysis of all lymphomas according to MYC partner (IG/non-IG) revealed no substantial differences. In contrast to mBL and lymphomas without MYC break, SHL and DHL patients had similar poor outcome. Our data suggest that after excluding mBL, MYC+ lymphomas could be biologically widely lumped without further need for subclassification.
2013-12-31 | GSE44164 | GEO
Project description:MYC translocations are the biologic hallmark of Burkitt lymphomas but also occur in other mature B-cell lymphomas. If accompanied by chromosomal breaks targeting the BCL2 and/or BCL6 oncogenes, these MYC translocation-positive (MYC+) lymphomas are called double-hit lymphomas (DHLs); otherwise, the term single-hit lymphoma (SHL) is applied. In order to characterize the biologic features of these MYC+ lymphomas other than Burkitt lymphomas, we explored, after exclusion of molecular Burkitt lymphoma (mBL) as defined by gene expression profiling (GEP), the molecular, pathological and clinical aspects of 80 MYC translocation (MYC+) lymphomas (31 SHL, 26 BCL2+/MYC+, 14 BCL6+/MYC+, 6 BCL2+/BCL6+/MYC+ and 3 MYC+ lymphomas with unknown BCL6 status). Comparison of SHL and DHL revealed no difference in frequency of MYC partner (IG/non-IG), genomic complexity or MYC expression and no differences in GEP. DHL showed a more frequent GCB-like GEP and higher IGH and MYC mutation rates. GEP revealed 130 differentially expressed genes between BCL6+/MYC+ and BCL2+/MYC+ DHL. BCL2+/MYC+ DHL showed a more frequent GCB-like GEP. Analysis of all lymphomas according to MYC partner (IG/non-IG) revealed no substantial differences. In contrast to mBL and lymphomas without MYC break, SHL and DHL patients had similar poor outcome. Our data suggest that after excluding mBL, MYC+ lymphomas could be biologically widely lumped without further need for subclassification. 32 diffuse large B-cell lymphoma samples were hybridized to HG-U133A Affymetrix GeneChips. In addition, this study contains 30 already published samples, which contribute to GSE4475 (Hummel et al. 2006 (PMID 16760442)), as well as 18 already published samples from GSE22470 (Salaverria et al. 2011 (PMID 21487109)). No re-normalisation of the published samples was performed. The complete dataset representing: (1) the 32 diffuse large B-cell lymphoma Samples, (2) the 30 Samples from GSE4475 and (3) the 18 Samples from GSE22470, is linked below as a supplementary file
2013-12-31 | E-GEOD-44164 | biostudies-arrayexpress
Project description:The histone mark H3K27me3 and its reader/writer Polycomb repressive complex 2 (PRC2) mediate widespread transcriptional repression in stem and progenitor cells. Mechanisms that regulate this activity are critical for tissue development but poorly understood. Here we show that the E3 ubiquitin ligase FBXO11 relieves PRC2-mediated repression during erythroid maturation by targeting its newly identified substrate BAHD1, an H3K27me3 reader that recruits transcriptional co-repressors. Erythroblasts lacking FBXO11 are developmentally delayed, with reduced expression of maturation-associated genes, most of which harbor bivalent histone marks (activating H3K4me3 and repressive H3K27me3), bind BAHD1, and fail to recruit the erythroid transcription factor GATA1. The BAHD1 complex interacts physically with PRC2 and depletion of either component restores FBXO11-deficient erythroid gene expression. Previous studies showed that FBXO11 promotes B-cell development and inhibits lymphomagenesis by degrading the transcriptional repressor BCL6. We show that in aggressive B-cell lymphoma lines, depletion of FBXO11 causes the accumulation of both BCL6 and BAHD1, and that suppression of BAHD1 slows cell expansion. Our studies identify BAHD1 as a novel effector of PRC2-mediated repression and reveal how a single E3 ubiquitin ligase eliminates PRC2 repression at developmentally poised bivalent genes during erythropoiesis. The FBXO11-BAHD1 regulatory axis may function in other developmental pathways, including B-lymphopoiesis and lymphomagenesis.
2020-12-31 | GSE115357 | GEO
Project description:Recently, a subset of MYC-translocation negative aggressive B-cell lymphomas resembling Burkitt lymphoma (BL) characterized by proximal gains and distal losses in the long arm of chromosome 11 has been described. In the 2016 revision of the WHO classification these MYC-translocation negative lymphomas have been introduced as new provisional entity designated “Burkitt-like lymphoma with 11q aberration” (MNBLL 11q). Here, we show a comprehensive flow-cytometry analysis of 10 MNBLL 11q cases, well characterized genetically and pathologically. Twenty-three cases of MYC-positive BL, including three cases carrying both MYC rearrangements and 11q aberration, served as controls. All MNBLL 11q were CD20+/CD10+/BCL6+/BCL2- /MUM1- /MYC+/EBV negative , presented a high proliferation rate and showed a three-year overall survival (80%) similar to BL patients, with no recurrence after the end of treatment. MNBLL 11q immunophenotype was similar to that of MYC-positive BL without and with 11q, except for less frequent CD38higher expression (10% MNBLL 11q vs 91% MYC-positive BL, p<0.001), less frequent diminished CD45 expression (90% vs 23%, p=0.001), and CD16/CD56 co-expression (60% vs 0%, p<0.001). Our findings suggest subtle but important differences in MNBLL 11q immunophenotypes and MYC-positive BLs, which could not only aid in the differential diagnosis but also in the understanding of the pathogenesis of MNBLL 11q.
2019-07-30 | GSE93002 | GEO
Project description:Burkitt lymphoma is the commonest cancer in children in Africa. We compared the gene expression profiles of African Burkitt lymphoma patients with those of cases presented in Western countries in both immunocompetent (sporadic Burkitt lymphoma) and HIV-infected patients (immunodeficiency associated Burkitt lymphoma). We used microarrays to detail the global programme of gene expression in different subtypes of Burkitt lymphoma.
2011-01-20 | GSE26673 | GEO
Project description:Burkitt lymphoma is the commonest cancer in children in Africa. We compared the gene expression profiles of African Burkitt lymphoma patients with those of cases presented in Western countries in both immunocompetent (sporadic Burkitt lymphoma) and HIV-infected patients (immunodeficiency associated Burkitt lymphoma). We used microarrays to detail the global programme of gene expression in different subtypes of Burkitt lymphoma. Lymph-node biopsies were collected at diagnosis. Gene expression profiles were generated with the Affymetrix HG U133 2.0 plus microarray
2011-01-20 | E-GEOD-26673 | biostudies-arrayexpress
Project description:Burkitt Lymphoma cell lines were established and used for methylome profiling with Illumina HM450 beadchip
2017-07-24 | GSE92378 | GEO
Project description:Burkitt lymphoma (BL) is the most frequent B-cell lymphoma in pediatric patients. While most patients are currently cured, a fraction of them are resistant to therapy. In order to investigate BL heterogeneity and the features distinguishing the non-responders (NR) to therapy, we analyzed pediatric EBV-negative BL specimens collected at diagnosis by single-cell (sc)-transcriptomics. Analysis of the non-tumor component revealed a predominance of immune cell infiltrates and a small representation of fibroblasts that was enriched in NR. Tumor cells displayed patient-specific features, as well as subpopulations that were common to most patients and expressed transcripts related to cell cycle, signaling pathways and cell-of-origin signatures.
2024-10-24 | GSE240252 | GEO