The double-hit signature identifies double-hit diffuse large B-cell lymphoma with genetic events cryptic to FISH​
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ABSTRACT:
PROVIDER: EGAS00001004285 | EGA |
REPOSITORIES: EGA
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Project description:Diffuse large B-cell lymphoma (DLBCL) represents a heterogeneous diagnostic category with distinct molecular subtypes that can be defined by gene expression profiling. However, even within these defined subtypes, heterogeneity prevails. To further elucidate the pathogenesis of these entities, we determined the expression of the tumor suppressor phosphatase and tensin homolog (PTEN) in 248 primary DLBCL patient samples. These analyses revealed that loss of PTEN was detectable in 55% of germinal center B-cell-like (GCB) DLBCLs, whereas this abnormality was found in only 14% of non-GCB DLBCL patient samples. In GCB DLBCL, the PTEN status was inversely correlated with activation of the oncogenic PI3K/ protein kinase B (AKT) pathway in both DLBCL cell lines and primary patient samples. Re-expression of PTEN induced cytotoxicity in PTEN-deficient GCB DLBCL cell line models by inhibiting PI3K/AKT signaling, indicating an addiction to this pathway in this subset of GCB DLBCLs. PI3K/AKT inhibition induced down-regulation of the transcription factor MYC. Re-expression of MYC rescued GCB DLBCL cells from PTEN-induced toxicity, identifying a regulatory mechanism of MYC expression in DLBCL. Finally, pharmacologic PI3K inhibition resulted in toxicity selectively in PTEN-deficient GCB DLBCL lines. Collectively, our results indicate that PTEN loss defines a PI3K/ AKT-dependent GCB DLBCL subtype that is addicted to PI3K and MYC signaling and suggest that pharmacologic inhibition of PI3K might represent a promising therapeutic approach in these lymphomas.
2013-07-09 | GSE45495 | GEO
Project description:The pathogenesis of c-MYC and BCL2 double-expressor diffuse large B cell lymphoma (DE DLBCL) remains unclear, particularly in terms of the tumor microenvironment. We aimed to analyze the immune microenvironment of DE DLBCLs to understand the basis of DE-DLBCL's aggressiveness and identify potential therapeutic targets. To discover the key features of DE-DLBCL, fourteen non-DE and 14 DE DLBCL samples underwent RNA-seq analysis. For validation, formalin-fixed paraffin-embedded tissues from 126 patients were immunostained for CD3, CD4, CD8, FOXP3, CD68 and CD163. Two c-MYClow/BCL2low DLBCL (SU-DHL-10 and HT) and 2 c-MYChigh/BCL2high DLBCL cell lines (DOHH2 and OCI-LY8) were used for in vitro assays. The prognostic impact of differential chemokine secretion and immune profiles was evaluated in a mouse tumor model. RNA-seq analysis revealed significantly higher CCL2 and CCR2 mRNA in DE DLBCLs (Padj < 0.05). Public datasets showed higher M2/macrophage ratio and lower T cell infiltration in DE DLBCLs (P < 0.05). Immunohistochemistry confirmed higher M2 macrophages and M2/total macrophage ratio in DE DLBCL (P=0.010 and P=0.098, respectively). In vitro, c-MYChigh/BCL2high cell lines exhibited increased CCL2 secretion, as seen in RNA-seq analysis. Knockdown and overexpression studies identified that MYC and BCL2 overexpression increased CCL2 secretion by upregulation of NF-κB p65 subunit, and the increased CCL2 secretion was crucial for M2 polarization. In mouse tumor models, CCL2 was related to aggressive tumor growth and an immunosuppressive tumor microenvironment. In conclusion, the increased CCL2/CCR2 axis confers aggressiveness of DE DLBCLs by increasing M2 polarization.
2024-09-30 | GSE252690 | GEO
Project description:B cell receptor (BCR) signaling has emerged as a therapeutic target in B cell lymphomas, but the precise deployment of inhibitors to target oncogenic BCR signaling requires detailed knowledge of the signaling cascades that the BCR triggers in individual tumors. Here, we have used CRISPR-Cas9 screens to investigate whether the ABC and GCB molecular subtypes of diffuse large B cell lymphoma (DLBCL) utilize distinct BCR signaling modes to sustain their proliferation and survival. Constitutive germinal center (GC) BCR signaling in GCB DLBCLs requires the BCR, CD19 and SYK engaging PI(3) kinase for survival. In ABC DLBCLs with oncogenic mutations in the BCR and MYD88, a novel BCR-TLR9-MYD88 signaling supercomplex is assembled on endolysosomal membranes that engages NF-kB. Our data explain why this subset of ABC DLBCL tumors respond frequently to ibrutinib, an inhibitor of BCR-dependent NF- kB activation, while GCB DLBCLs are insensitive, and thus provide a roadmap for the rational development of BCR pathway inhibitors in molecular subtypes of DLBCL.
2018-05-01 | GSE99276 | 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.
2013-12-31 | GSE44164 | GEO
Project description:Diffuse large B-cell lymphoma (DLBCL) represents a heterogeneous diagnostic category with distinct molecular subtypes that can be deM-oM-,M-^Aned by gene expression proM-oM-,M-^Aling. However, even within these deM-oM-,M-^Aned subtypes, heterogeneity prevails. To further elucidate the pathogenesis of these entities, we determined the expression of the tumor suppressor phosphatase and tensin homolog (PTEN) in 248 primary DLBCL patient samples. These analyses revealed that loss of PTEN was detectable in 55% of germinal center B-cell-like (GCB) DLBCLs, whereas this abnormality was found in only 14% of non-GCB DLBCL patient samples. In GCB DLBCL, the PTEN status was inversely correlated with activation of the oncogenic PI3K/ protein kinase B (AKT) pathway in both DLBCL cell lines and primary patient samples. Reexpression of PTEN induced cytotox- icity in PTEN-deM-oM-,M-^Acient GCB DLBCL cell line models by inhibiting PI3K/AKT signaling, indicating an addiction to this pathway in this subset of GCB DLBCLs. PI3K/AKT inhibition induced down-regulation of the transcription factor MYC. Reexpression of MYC rescued GCB DLBCL cells from PTEN-induced toxicity, identifying a regulatory mechanism of MYC expression in DLBCL. Finally, pharmacologic PI3K inhibition resulted in toxicity selectively in PTEN-deM-oM-,M-^Acient GCB DLBCL lines. Collectively, our results indicate that PTEN loss deM-oM-,M-^Anes a PI3K/ AKT-dependent GCB DLBCL subtype that is addicted to PI3K and MYC signaling and suggest that pharmacologic inhibition of PI3K might represent a promising therapeutic approach in these lymphomas. This GEO dataset is comprised of a) GEP measurements for 34 primary DLBCL patient samples plus two reference samples, b) 8 paired GEP measurements of the HT DLBCL cell line and c) aCGH measurements for two DLBCL cell lines in addition to previously published cell lines in GSE43272 (i.e., Sample GSM1059798). All of these data were used in the paper cited below.
2013-07-09 | E-GEOD-45495 | biostudies-arrayexpress
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:Epigenetic heterogeneity is emerging as a significant phenotypic feature of tumors. In diffuse large B-cell lymphomas (DLBCLs), increased cytosine methylation heterogeneity is associated with poor clinical outcome, yet the biological mechanisms driving epigenetic heterogeneity remain unclear. Activation-induced cytidine deaminase (AICDA), an enzyme that deaminates and facilitates demethylation of DNA methyl-cytosines in germinal center (GC) B-cells, is required for DLBCL pathogenesis and linked to inferior clinical outcomes. Here, we show that overexpression of AICDA causes more aggressive disease and worse outcome in BCL2-driven murine lymphomas. This phenotype was associated with significantly increased focal inter-tumor and intra-tumor cytosine methylation heterogeneity as compared to control lymphomas, but not with increased mutational burden. AICDA-mediated epigenetic heterogeneity was accompanied by DNA hypomethylation. Reciprocally, we observed that the focal inter-individual and intra-individual cytosine methylation heterogeneity characteristic of normal GC B-cells was lost upon depletion of AICDA. There was significant overlap of AICDA-induced methylation heterogeneity foci in GC B-cells and murine lymphomas. These observations are relevant to human patients, since DLBCLs with high AICDA expression likewise manifest extensive increases in focal inter-patient and intra-patient heterogeneity as compared to DLBCLs with low AICDA expression. Affected regions significantly overlapped with those found in murine AICDA-overexpressing lymphomas. Our results identify AICDA as a novel source of epigenetic plasticity and heterogeneity in B-cell lymphomas with potential significance for other tumors that express cytosine deaminases.
2018-01-19 | GSE95013 | GEO
Project description:Aggressive double and triple hit (DH/TH) DLBCL feature activation of Hsp90 stress pathways. Herein, we show that Hsp90 controls post-transcriptional dynamics of key mRNA species including those encoding BCL6, MYC and BCL2. Using a proteomics approach, we found that Hsp90 binds to and maintains activity of eIF4E (eukaryotic translation initiation factor 4E). EIF4E drives nuclear export and translation of BCL6, MYC and BCL2 mRNA. eIF4E RIP-sequencing in DLBCL suggests that nuclear eIF4E controls an extended program that includes BCR signaling, cellular metabolism and epigenetic regulation. Accordingly, eIF4E was required for survival of DLBCL including the most aggressive subtypes DH/TH lymphomas. Indeed, eIF4E inhibition induces tumor regression in cell line and patient-derived tumorgrafts of TH-DLBCL, even in the presence of elevated Hsp90 activity. Targeting Hsp90 is typically limited by counter-regulatory elevation of Hsp70B, which induces resistance to Hsp90 inhibitors. Surprisingly, we identify Hsp70 mRNA as an eIF4E target. In this way, eIF4E inhibition can overcome drug resistance to Hsp90 inhibitors. Accordingly, rational combinatorial inhibition of eIF4E and Hsp90 inhibitors resulted in cooperative anti-lymphoma activity in DH/TH DLBCL in vitro and in vivo. We found that eIF4E activity regulates the nuclear export of BCL6, MYC, and BCL2 in DH/TH DLBCLs. To determine the extent of nuclear eIF4E activity in DH/TH DLBCLs and how these programs can support the oncogenic activity of BCL6, MYC and/or BCL2 transcripts, we conducted eIF4E-RIP of nuclear RNA followed by RNA-sequencing in OCI-Ly1 cells in triplicates. To understand the changes in gene expression after ribavarin in a clinically relevant sample, we generated a patient-derived xenograft (PDX) in NSG mice from a de-identified specimen isolated from a patient prior to treatment harboring a triple-hit ABC-type DLBCL. PDX cells from passage four (PDX-4) were implanted into NSG mice. When tumors were palpable, mice were randomized to receive vehicle or 80 mg/kg/b.i.d. ribavarin intraperitoneally for 10 days. We isolated RNA from tumors treated with vehicle (n=2) or ribavarin (n=2) and performed mRNA-seq.
2016-01-11 | E-GEOD-63265 | biostudies-arrayexpress
Project description:<p>Diffuse large B-cell lymphoma (DLBCL), the most common lymphoid malignancy in adults, is a clinically and genetically heterogenous disease that is further classified into transcriptionally defined activated B-cell (ABC) and germinal center B-cell (GCB) subtypes. Here, we describe a comprehensive genetic analysis of DLBCLs that identifies low-frequency alterations, captures recurrent mutations, copy number alterations (CNAs) and structural variants (SVs) and characterizes coordinate genetic signatures in 304 primary DLBCLs with available outcome data. We integrated these genetic drivers using consensus clustering and identified 5 robust DLBCL subsets, including a previously unrecognized group of low-risk ABC-DLBCLs of extrafollicular/marginal zone origin; 2 distinct subsets of GCB-DLBCLs with different outcomes and targetable alterations; and an ABC/GCB-independent group with biallelic inactivation of TP53, CDKN2A loss and associated genomic instability. The genetic features of the newly identified subsets, their mutational signatures and the temporal ordering of identified alterations provide new insights into DLBCL pathogenesis. The coordinate genetic signatures also predict outcome independent of the clinical International Prognostic Index and suggest new combination treatment strategies. More broadly, these studies provide a roadmap for an actionable DLBCL classification. </p>
| phs000450 | dbGaP
Project description:The EZH2 histone methyltransferase is highly expressed in germinal center (GC) B-cells and targeted by somatic mutations in B-cell lymphomas. Here we find that EZH2 deletion or pharmacologic inhibition suppresses GC formation and functions in mice. EZH2 represses proliferation checkpoint genes and helps establish bivalent chromatin domains at key regulatory loci to transiently suppress GC B-cell differentiation. Somatic mutations reinforce these physiological effects through enhanced silencing of EZH2 targets in B-cells, and in human B-cell lymphomas. Conditional expression of mutant EZH2 in mice induces GC hyperplasia and accelerated lymphomagenesis in cooperation with BCL2. GCB-type DLBCLs are mostly addicted to EZH2, regardless of mutation status, but not the more differentiated ABC-type DLBCLs, thus clarifying the therapeutic scope of EZH2 targeting.
2013-05-13 | GSE45982 | GEO