Selective inhibition of HDAC3 targets synthetic vulnerabilities and activates immune surveillance in lymphoma
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE142357 | GEO | 2020/06/12
REPOSITORIES: GEO
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Project description:Despite selective HDAC3 inhibition showing promise in a subset of lymphomas with CREBBP mutations, wild-type tumors generally exhibit resistance. Here, using unbiased genome-wide CRISPR screening, we identify GNAS knockout (KO) as a sensitizer of resistant lymphoma cells to HDAC3 inhibition. Mechanistically, GNAS KO-induced sensitization is independent of the canonical G-protein activities but unexpectedly mediated by viral mimicry-related interferon (IFN) responses, characterized by TBK1 and IRF3 activation, double-stranded RNA formation, and transposable element (TE) expression. GNAS KO additionally synergizes with HDAC3 inhibition to enhance CD8+ T cell-induced cytotoxicity. Moreover, we observe in human lymphoma patients that low GNAS expression is associated with high baseline TE expression and upregulated IFN signaling and shares common disrupted biological activities with GNAS KO in histone modification, mRNA processing, and transcriptional regulation. Collectively, our findings establish an unprecedented link between HDAC3 inhibition and viral mimicry in lymphoma. We suggest low GNAS expression as a potential biomarker that reflects viral mimicry priming for enhanced response to HDAC3 inhibition in the clinical treatment of lymphoma, especially the CREBBP wild-type cases.
2024-08-08 | GSE268034 | GEO
Project description:Somatic mutations affecting CREBBP and EP300 are a hallmark of Diffuse Large B Cell Lymphoma (DLBCL). These mutations are frequently monoallelic, within the histone acetyltransferase (HAT) domain and usually mutually exclusive, suggesting that they might affect a common pathway and their residual WT expression is required for cell survival. Using in vitro and in vivo models, we found that inhibition of CARM1 activity (CARM1i) slows DLBCL growth and that the levels of sensitivity are positively correlated with the CREBBP/EP300 mutation load. Conversely, treatment of DLBCLs that do not have CREBBP/EP300 mutations with CARM1i and a CBP/p300 inhibitor revealed a strong synergistic effect. Our mechanistic data show that CARM1i further reduces the HAT activity of CBP genome wide and downregulates CBP target genes in DLBCL cells, resulting in a synthetic lethality that leverages the mutational status of CREBBP/EP300 as a biomarker for the use of small molecule inhibitors of CARM1 in DLBCL and other cancers.
2020-06-18 | GSE152665 | GEO
Project description:Somatic mutations affecting CREBBP and EP300 are a hallmark of Diffuse Large B Cell Lymphoma (DLBCL). These mutations are frequently monoallelic, within the histone acetyltransferase (HAT) domain and usually mutually exclusive, suggesting that they might affect a common pathway and their residual WT expression is required for cell survival. Using in vitro and in vivo models, we found that inhibition of CARM1 activity (CARM1i) slows DLBCL growth and that the levels of sensitivity are positively correlated with the CREBBP/EP300 mutation load. Conversely, treatment of DLBCLs that do not have CREBBP/EP300 mutations with CARM1i and a CBP/p300 inhibitor revealed a strong synergistic effect. Our mechanistic data show that CARM1i further reduces the HAT activity of CBP genome wide and downregulates CBP target genes in DLBCL cells, resulting in a synthetic lethality that leverages the mutational status of CREBBP/EP300 as a biomarker for the use of small molecule inhibitors of CARM1 in DLBCL and other cancers.
2020-06-18 | GSE152667 | GEO
Project description:Somatic mutations affecting CREBBP and EP300 are a hallmark of Diffuse Large B Cell Lymphoma (DLBCL). These mutations are frequently monoallelic, within the histone acetyltransferase (HAT) domain and usually mutually exclusive, suggesting that they might affect a common pathway and their residual WT expression is required for cell survival. Using in vitro and in vivo models, we found that inhibition of CARM1 activity (CARM1i) slows DLBCL growth and that the levels of sensitivity are positively correlated with the CREBBP/EP300 mutation load. Conversely, treatment of DLBCLs that do not have CREBBP/EP300 mutations with CARM1i and a CBP/p300 inhibitor revealed a strong synergistic effect. Our mechanistic data show that CARM1i further reduces the HAT activity of CBP genome wide and downregulates CBP target genes in DLBCL cells, resulting in a synthetic lethality that leverages the mutational status of CREBBP/EP300 as a biomarker for the use of small molecule inhibitors of CARM1 in DLBCL and other cancers.
2020-06-18 | GSE152666 | GEO
Project description:<p><b>Version 1.</b> Diffuse Large B-cell Lymphoma (DLBCL) represents the most common form of B-cell non-Hodgkin Lymphoma (B-NHL), accounting for ~30% of the <i>de novo</i> diagnoses and also arising as a frequent clinical evolution of Follicular Lymphoma (FL). The molecular pathogenesis of DLBCL is associated with multiple genetic lesions that in part distinctly segregate with individual phenotypic subtypes, suggesting the involvement of distinct oncogenic pathways. However, the lesions identified so far likely represent only a fraction of those necessary for malignant transformation. In order to characterize the entire set of structural alterations present in the DLBCL genome, we have integrated next generation whole exome sequencing analysis of 6 DLBCL cases and genome-wide high-density SNP array analysis of 72 DLBCL cases. We report here that FL and DLBCL harbor frequent structural alterations inactivating <i>CREBBP</i> and, more rarely, <i>EP300</i>, two highly related histone and non-histone acetyltransferases (HATs) that act as transcriptional co-activators in multiple signaling pathways. Overall, ~37% of DLBCL and 36% of FL cases display genomic deletions and/or somatic point mutations that remove or inactivate the HAT coding domain of these two genes. These lesions commonly affect a single allele, suggesting that reduction in HAT dosage is important for lymphomagenesis. We demonstrate specific defects in the acetylation-mediated inactivation of the BCL6 oncoprotein and activation of the p53 tumor suppressor. These results identify <i>CREBBP/EP300</i> mutations as a major pathogenic mechanism shared by common forms of B-NHL, and have direct implications for the use of drugs targeting acetylation/deacetylation mechanisms.</p> <p><b>Version 2.</b> Follicular lymphoma (FL) is an indolent, but incurable disease that, in 30-40% of cases, undergoes transformation to an aggressive diffuse large B cell lymphoma (DLBCL). The history of clonal evolution and the mechanisms that underlie transformation to DLBCL (tFL) remain largely unknown. Using whole exome sequencing and copy number analysis of 39 tFL patients, including 12 with paired sequential FL/tFL biopsies, we show that, in most cases, FL and tFL arise by divergent evolution from a common mutated precursor cell through the acquisition of distinct genetic lesions. Mutations in epigenetic modifiers (e.g., <i>MLL2, CREBBP, EZH2, ARID1A</i>) and anti-apoptotic genes (<i>BCL2, FAS</i>) were observed in 93% (36/39) and 78% (30/39) of cases, respectively, and were invariably shared between the two disease phases, suggesting an early acquisition in the common mutated precursor. Conversely, the development of tFL is associated with deregulation of genes involved in the control of cell proliferation, cell cycle progression and DNA damage responses (<i>CDKN2A/2B, MYC, TP53</i>), as well as with an aberrant activity of the somatic hypermutation mechanism. Finally, we show that the genomic profile of tFL shares significant similarities with that of germinal center B-cell type <i>de novo</i> DLBCL, but also displays unique combinations of altered genes that may explain the dismal clinical course of tFL.</p>
| phs000328 | dbGaP
Project description:Purpose: Diffuse large B cell lymphomas (DLBCL) frequently harbor mutations in the histone acetyltransferase CREBBP, however their functional contribution to lymphomagenesis remains largely unknown. This study aims at elucidating and characterizing the molecular pathways affected by mutations in CREBBP. Methods: U2932, a DLBCL cell line that has wild type expression of CREBBP was manipulated by CRISPR-Cas9 strategy to mutate one allele of CREBBP and examine the pathways affected. RNA was isolated using the NucleoSping RNA Kit (Macherey-Nagel) from five wild type (CREBBP+/+) and five heterozygous clones (CREBBP+/-). RNA quality was assessed by Bioanalyzer 2100 followed by library preparation using the TruSeq RNA Sample Prep Kit v4 (Illumina). Sequencing was subsequently performed on the Illumina HiSeq 2500 instrument. RNA-seq reads were quality-checked with fastqc, which computes various quality metrics for the raw reads. RNA-seq reads were mapped to the GRCh38 reference human genome using STAR and reads were counted according to Ensembl gene annotation using the featureCounts function in the Rsubread Bioconductor package. Statistical analysis of differential expression was conducted with the DESeq2 package.
2016-11-16 | GSE89879 | GEO
Project description:Inactivating mutations of the CREBBP acetyltransferase and, at lower frequencies, its paralogue EP300 are among the most common genetic alterations in diffuse large B-cell lymphoma (DLBCL) and follicular lymphoma (FL), the two most frequent B cell malignancies. Here we uncover unexpected distinct functions for CREBBP and EP300 in the germinal center (GC), i.e. the target structure for most human B cell lymphomas. We show that these proteins modulate non-overlapping transcriptional programs that are preferentially enriched in biological functions associated with the separate anatomic compartments of the GC. Consistently, deletion of CREBBP or EP300 have opposing effects on GC formation in vivo. Nonetheless, these proteins partially compensate for each other to maintain a minimal threshold of acetyltransferase activity and guarantee homeostatic control of the GC, which is completely abrogated by their combined loss. This synthetic lethal interaction is retained in DLBCL cells, identifying an Achille’s heel in CREBBP-mutant lymphomas that could be pharmacologically targeted by using a novel, selective small molecule inhibitor of the CREBBP/EP300 bromodomain. These data shed light on the unique roles of CREBBP and EP300 in the physiology and pathology of GC B cells, and provide a proof-of-principle for the development and testing of EP300 inhibition as a therapeutic strategy in these diseases.
2020-02-19 | GSE132365 | GEO
Project description:Inactivating mutations of the CREBBP acetyltransferase and, at lower frequencies, its paralogue EP300 are among the most common genetic alterations in diffuse large B-cell lymphoma (DLBCL) and follicular lymphoma (FL), the two most frequent B cell malignancies. Here we uncover unexpected distinct functions for CREBBP and EP300 in the germinal center (GC), i.e. the target structure for most human B cell lymphomas. We show that these proteins modulate non-overlapping transcriptional programs that are preferentially enriched in biological functions associated with the separate anatomic compartments of the GC. Consistently, deletion of CREBBP or EP300 have opposing effects on GC formation in vivo. Nonetheless, these proteins partially compensate for each other to maintain a minimal threshold of acetyltransferase activity and guarantee homeostatic control of the GC, which is completely abrogated by their combined loss. This synthetic lethal interaction is retained in DLBCL cells, identifying an Achille’s heel in CREBBP-mutant lymphomas that could be pharmacologically targeted by using a novel, selective small molecule inhibitor of the CREBBP/EP300 bromodomain. These data shed light on the unique roles of CREBBP and EP300 in the physiology and pathology of GC B cells, and provide a proof-of-principle for the development and testing of EP300 inhibition as a therapeutic strategy in these diseases.
2021-06-01 | GSE124192 | GEO
Project description:Diffuse large B-cell lymphomas (DLBCL) encompass a heterogeneous group of diseases derived from different stages of B-cell differentiation. The most clinically aggressive forms of DLBCL, C5/MCD, carry activating mutations in canonical B-cell signaling pathways, as well as early-occurring hits in the poorly-characterized gene TBL1XR1. Here, we investigated the role of TBL1XR1 mutations in the early steps of malignant transformation. We found that TBL1XR1 mutations disrupt germinal center development, and introduce a cell fate bias towards memory B (MB) cells. At the molecular level, TBL1XR1 mutations trigger a switch, by which the SMRT/HDAC3 co-repressor complex shuttles between the lineage-defining transcription factors BCL6 and BACH2. We further demonstrate that terminal differentiation of TBL1XR1 mutant MB is limited upon recall, and that these MB re-enter the germinal center reaction instead, suggesting a role for these cells as the cell-of-origin of C5/MCD DLBCL.
2020-07-02 | GSE139059 | GEO
Project description:Inactivating mutations of the gene encoding for the CREBBP acetyltransferase are highly frequent in diffuse large B cell lymphoma (DLBCL, 30% of cases) and follicular lymphoma (FL, 60% of cases), the two most common cancers derived from the germinal-center (GC). However, the role of CREBBP inactivation in lymphomagenesis remains unclear. Using functional epigenomics and mouse genetics, here we define the program modulated by CREBBP in primary human GC B cells and show that CREBBP regulates enhancer/super-enhancer networks, with specific roles in GC/post-GC cell fate decisions. Conditional GC-specific deletion of Crebbp in the mouse perturbs the expression of a limited set of genes involved in the regulation of signal transduction (BCR, TLR and CD40), lineage specification (NF-κB and BCL6) and terminal B cell differentiation (PRDM1, IRF4). Consistently, Crebbp-deficient B cells exhibit proliferative advantage and show impaired plasma cell differentiation. While GC-specific loss of Crebbp was not sufficient to initiate malignant transformation, compound Crebbp-haploinsufficient/BCL2-transgenic mice, mimicking the genetics ofFL and DLBCL, display an increased incidence of clonal lymphoid malignancies recapitulating the features of the human diseases. These findings establish CREBBPas a haploinsufficient tumor suppressor gene in GC B cells and provide insights into the mechanisms and targets by which loss of CREBBP contributes to lymphomagenesis.
2017-01-11 | GSE89688 | GEO