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KDM5 inhibition is a novel therapeutic strategy for the treatment of KMT2D mutant lymphomas [2]

ABSTRACT: Loss of function mutations within KMT2D are a striking feature of the germinal centre lymphomas, with lesions present in 80% of Follicular Lymphoma (FL) and 30% of Diffuse Large B-cell Lymphoma (DLBCL), resulting in decreased H3K4 methylation and altered gene expression. The KDM5 family normally maintains homeostasis through demethylating H3K4me3/2, thus negatively regulating gene expression. We hypothesised that inhibition of KDM5 may re-establish H3K4 methylation and restore the expression of genes repressed upon loss of KMT2D. Using a selective inhibitor of the KDM5 family we were able to increase H3K4me3 levels in DLBCL cell lines, predominantly at gene promoters, ultimately leading to decreased proliferation and cell death in KMT2D mutant cell lines. This appeared to be driven by an increase in the expression of negative regulators of B cell survival pathways, many of which have previously been described as targets of KMT2D and CREBBP, resulting in diminished BCR signalling. We also observed decreased BCL2 expression in all examined t(14;18) positive cell lines, alongside changes in other BCL2 family members in sensitive cell lines. KDM5 sensitivity was confirmed to be dependent on the presence of KMT2D mutations by generating de novo KMT2D mutant cell lines and correcting naturally mutant cell lines, which displayed greater and lesser sensitivity to KDM5 inhibition respectively. KDM5 inhibition may therefore be an effective therapeutic strategy for ameliorating KMT2D loss of function mutations in malignancies such as germinal centre lymphomas.

ORGANISM(S): Homo sapiens

PROVIDER: GSE152642 | GEO | 2021/06/01

REPOSITORIES: GEO

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KDM5 inhibition is a novel therapeutic strategy for the treatment of KMT2D mutant lymphomas [1]

Project description:Loss of function mutations within KMT2D are a striking feature of the germinal centre lymphomas, with lesions present in 80% of Follicular Lymphoma (FL) and 30% of Diffuse Large B-cell Lymphoma (DLBCL), resulting in decreased H3K4 methylation and altered gene expression. The KDM5 family normally maintains homeostasis through demethylating H3K4me3/2, thus negatively regulating gene expression. We hypothesised that inhibition of KDM5 may re-establish H3K4 methylation and restore the expression of genes repressed upon loss of KMT2D. Using a selective inhibitor of the KDM5 family we were able to increase H3K4me3 levels in DLBCL cell lines, predominantly at gene promoters, ultimately leading to decreased proliferation and cell death in KMT2D mutant cell lines. This appeared to be driven by an increase in the expression of negative regulators of B cell survival pathways, many of which have previously been described as targets of KMT2D and CREBBP, resulting in diminished BCR signalling. We also observed decreased BCL2 expression in all examined t(14;18) positive cell lines, alongside changes in other BCL2 family members in sensitive cell lines. KDM5 sensitivity was confirmed to be dependent on the presence of KMT2D mutations by generating de novo KMT2D mutant cell lines and correcting naturally mutant cell lines, which displayed greater and lesser sensitivity to KDM5 inhibition respectively. KDM5 inhibition may therefore be an effective therapeutic strategy for ameliorating KMT2D loss of function mutations in malignancies such as germinal centre lymphomas.

2021-06-01 | GSE114492 | GEO

Identification of KMT2D regulated genes in germinal center B cells

Project description:Somatic mutations of the KMT2D methyltransferase gene represent a common genetic lesion in multiple cancer types. In diffuse large B cell lymphoma (DLBCL) and follicular lymphoma (FL), these mutations are highly recurrent and occur early during tumorigenesis, suggesting a central role in transformation. Here we show that FL/DLBCL-associated KMT2D mutations impair its enzymatic activity and lead to diminished global H3K4 methylation in germinal center (GC) B cells and DLBCL, consistent with the enrichment of KMT2D binding at enhancer and promoter regions marked by mono- and tri-methylation. Conditional deletion of Kmt2d early during B cell development, but not after initiation of the GC reaction, leads to an increase in GC B cells, whose transcriptional profile is enriched in cell-cycle regulatory and B-cell receptor signaling genes. Consistently, Kmt2d-deficient B cells exhibit proliferative advantage ex vivo. Loss of Kmt2d combined with BCL2 deregulation, mimicking FL/DLBCL pathogenesis, leads to an increased incidence of clonal lymphoproliferations resembling the features of the human tumors. These findings suggest that early KMT2D loss facilitates lymphomagenesis by remodeling the epigenetic landscape of the cancer precursor cells. Eradication of KMT2D-deficient cells may represent a rational therapeutic approach targeting early tumorigenic events.

2015-09-10 | GSE67494 | GEO

Combinatorial targeting of MYC/BCL2 double-hit lymphoma with mitochondrial complex I and BCL2 inhibitors

Project description:Activation of the MYC oncogene is common in B-cell lymphomas, and frequently associated with compensatory events that dampen Myc-induced apoptosis, such as over-expression of anti-apoptotic Bcl2-family proteins. For example, concurrent translocations of MYC and BCL2 in a subset of Diffuse large B-cell lymphoma (DLBCL) lead to the high-grade “double-hit” lymphoma subtype (DHL), characterized by dismal prognosis in the face of current front-line regimens, thus calling for the pursuit of tailored therapeutic strategies. Here, we show that Myc and Bcl2 modulate the sensitivity of B-cells to IACS-010759, a selective inhibitor of mitochondrial respiratory complex I. Myc activation in non-transformed lymphoid precursors suppressed endogenous Bcl2 and sensitized the cells to IACS-010759-induced apoptosis. Treatment with the Bcl2 inhibitor venetoclax also sensitized to IACS-010759, while overexpression of Bcl-2 was protective. IACS-010759 engaged an ATF4-driven Integrated Stress Response (ISR) with dual anti- and pro-apoptotic effects, the latter mediated by the CHOP transcription factor, which contributed to selective killing of Myc-overexpressing cells. In line with the above data, IACS-010759 and venetoclax synergized in killing human DHL cells, and showed strong combinatorial effects in a pre-clinical setting. In a Bcl2-negative Burkitt’s lymphoma cell line, instead, IACS-010759 synergized with the Mcl-1 inhibitor S63845. Altogether, our data point to the combination of IACS-010759 with distinct Bcl2-family inhibitors for therapeutic reactivation of the intrinsic apoptotic pathway in Myc-associated B-cell lymphomas

2022-03-01 | GSE149073 | GEO

Clonal relationship of relapsing diffuse large B-cell lymphoma

Project description:Recurrences of diffuse large B-cell lymphomas (DLBCL) result in significant morbidity and mortality, but their underlying genetic and biological mechanisms are unclear. Clonal relationship in DLBCL relapses so far is mostly addressed by the investigation of immunoglobulin (IG) rearrangements, therefore lacking deeper insights into genome-wide lymphoma evolution. We studied mutations and copy number aberrations in 20 paired relapsing and 20 non-relapsing DLBCL cases aiming to test the clonal relationship between primaries and relapses, to track tumorsâ genetic evolution and to investigate the genetic background of DLBCL recurrence. Three clonally-unrelated DLBCL relapses were identified (15%). Also, two distinct patterns of genetic evolution in clonally-related relapses were detected: (1) early-divergent/branching evolution from a common progenitor in 6 patients (30%), and (2) late-divergent/linear progression of relapses in 11 patients (65%). Analysis of recurrent genetic events identified potential early drivers of lymphomagenesis (KMT2D, MYD88, CD79B and PIM1). The most frequent relapse-specific events were additional mutations in KMT2D and alterations of MEF2B. SOCS1 mutations were exclusive to non-relapsing DLBCL, whereas primaries of relapsing DLBCL more commonly displayed gains of 10p15.3-p12.1 containing the potential oncogenes PRKCQ, GATA3, MLLT10 and ABI1. Altogether, our study expands knowledge on clonal relationship, genetic evolution and mutational basis of DLBCL relapses. There are 62 copy number Agilent 180k SurePrint arrays in total, which represent 40 cases. There are 21 arrays of primary relapsing DLBCL tumors, 21 arrys of matched relapses and 20 arrays of non relapsing DLBCLs.

2016-06-01 | E-GEOD-65720 | biostudies-arrayexpress

KDM5 histone demethylases repress innate immune response via suppression of STING

Project description:Tri-methylation on histone H3 lysine 4 (H3K4me3) is enriched near transcription start sites and correlates with active transcription. Like other histone marks, methylation on H3K4 is catalyzed by the respective methyltransferases and erased by demethylases. Lysine demethylase 5 (KDM5) family of Fe (II) and α-ketoglutarate-dependent dioxygenases removes the methyl groups from H3K4me3. All four family members of KDM5 demethylases (KDM5A-D) share sequence identity, have similar in vitro kinetic parameters, and display functional redundancy. To determine the effects of complete depletion of KDM5 activity, we treated MCF7 cells with DMSO, or two pan-KDM5 specific inhibitors, KDM5-C70 (our lab code 443) and CPI-48 (our lab code 278) and performed RNA sequencing to determine gene expression changes after KDM5 inhibitor treatment.

2018-07-03 | GSE108502 | GEO

ChIP-seq analysis of H3K27me3 histone modification in EZH2 mutant and wild type DLBCL cell lines

Project description:In eukaryotes, epigenetic post-translational modification of histones is critical for regulation of chromatin structure and gene expression. EZH2 is the catalytic subunit of the Polycomb Repressive Complex 2 (PRC2) and is responsible for repressing target gene expression through methylation of histone H3 on lysine 27 (H3K27). Over-expression of EZH2 is implicated in tumorigenesis and correlates with poor prognosis in multiple tumor types. Recent reports have identified somatic heterozygous mutations of Y641 and A677 residues within the catalytic SET domain of EZH2 in diffuse large B-cell lymphoma (DLBCL) and follicular lymphoma (FL). The Y641 residue is the most frequently mutated residue, with 22% of GCB (Germinal centre B-cell) DLBCL and FL harboring mutations at this site. These lymphomas exhibit increased H3K27 tri-methylation (H3K27me3) due to altered substrate preferences of the mutant enzymes. However, it is unknown whether direct inhibition of EZH2 methyltransferase activity alone will be effective in treating lymphomas carrying activating EZH2 mutations. Herein, we demonstrate that GSK126, a potent, highly-selective, SAM-competitive, small molecule inhibitor of EZH2 methyltransferase activity, decreases global H3K27me3 levels and reactivates silenced PRC2 target genes. GSK126 effectively inhibits the proliferation of EZH2 mutant DLBCL cell lines and dramatically inhibits the growth of EZH2 mutant DLBCL xenografts in mice. Together, these data demonstrate that pharmacological inhibition of EZH2 activity may provide a promising treatment for EZH2 mutant lymphoma. We performed a ChIP-seq experiment to understand the genomewide pattern of H3K27me3 enrichment in DLBCL cell lines that were differentially sensitive to GSK126. H3K27me3 bound chromatin and input controls was immunoprecipitated and subjected to sequencing on the Illumina GA Iix. In total, 3 cell lines were profiled - 3 EZH2 mutant (Pfeiffer, KARPAS-422, WSU-DLCL2).

2012-10-12 | E-GEOD-40970 | biostudies-arrayexpress

Chemical reprogramming of human fibroblasts

Project description:The compound (O4I3) showed a remarkable OCT4 induction, which at least in part, is due to the inhibition of H3K4-specific lysine demethylase (KDM5, also known as JARID1). Experiments demonstrated that KDM5A, serves as a reprogramming barrier via interference with the enrichment of H3K4Me3 at the OCT4 promoter. Thus, our results introduce a new class of KDM5 chemical inhibitors and provide further insight into the pluripotency-related properties of KDM5-family members.

2018-12-12 | GSE123668 | GEO

Clonal relationship of relapsing diffuse large B-cell lymphoma

Project description:Recurrences of diffuse large B-cell lymphomas (DLBCL) result in significant morbidity and mortality, but their underlying genetic and biological mechanisms are unclear. Clonal relationship in DLBCL relapses so far is mostly addressed by the investigation of immunoglobulin (IG) rearrangements, therefore lacking deeper insights into genome-wide lymphoma evolution. We studied mutations and copy number aberrations in 20 paired relapsing and 20 non-relapsing DLBCL cases aiming to test the clonal relationship between primaries and relapses, to track tumors’ genetic evolution and to investigate the genetic background of DLBCL recurrence. Three clonally-unrelated DLBCL relapses were identified (15%). Also, two distinct patterns of genetic evolution in clonally-related relapses were detected: (1) early-divergent/branching evolution from a common progenitor in 6 patients (30%), and (2) late-divergent/linear progression of relapses in 11 patients (65%). Analysis of recurrent genetic events identified potential early drivers of lymphomagenesis (KMT2D, MYD88, CD79B and PIM1). The most frequent relapse-specific events were additional mutations in KMT2D and alterations of MEF2B. SOCS1 mutations were exclusive to non-relapsing DLBCL, whereas primaries of relapsing DLBCL more commonly displayed gains of 10p15.3-p12.1 containing the potential oncogenes PRKCQ, GATA3, MLLT10 and ABI1. Altogether, our study expands knowledge on clonal relationship, genetic evolution and mutational basis of DLBCL relapses.

2016-06-01 | GSE65720 | GEO

EZH2 is required for germinal center formation and somatic EZH2 mutations promote lymphoid transformation

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. RNA sequencing and H3K27me3 ChIP sequencing of human DLBCL cell lines and murine BCL1 cell line. RNA sequencing, H3K27me3 and H3K4me3 ChIP sequencing of B cells from de-identified human tonsills.

2013-05-13 | E-GEOD-45982 | biostudies-arrayexpress

Translocations Activating IRF4 Identify a Subtype of Germinal-Center-Derived B-cell Lymphoma Affecting Predominantly Children and Young Adults

Project description:Background: Germinal center B-cell (GCB) lymphomas are common in children and adults. The prognosis strongly depends on age. Subgroups of GCB-lymphomas are characterized by chromosomal translocations affecting immunoglobulin (IG) loci leading to oncogene deregulation. Methods: Novel IG translocation partners were cloned within the network “Molecular Mechanisms in Malignant Lymphomas” (MMML) by long-distance inverse polymerase chain reaction. Mature aggressive B-cell lymphomas from the MMML as well as pediatric and adult lymphoma trials were analyzed by fluorescence in situ hybridization (FISH) and immunhistochemistry. Data from 438 MMML cases characterized by gene expression profiling were mined. Results: Cloning of unknown IG partners identified a t(6;14)(p25;q32) juxtaposing the IRF4 oncogene with the IGH-locus as novel recurrent aberration in GCB lymphoma. FISH analyses of 427 mature B-cell lymphomas for IRF4 translocations revealed 20 IG/IRF4 positive lymphomas (17 IGH/IRF4, 2 IGL/IRF4, 1 IGΚ/IRF4). IG/IRF4-positive lymphomas were predominantly GCB-type diffuse large B-cell lymphomas (DLBCL) or follicular lymphoma grade 3, shared overexpression of IRF4/MUM1 and BCL6 and lacked PRDM1/BLIMP1 expression and t(14;18)/BCL2 breaks. BCL6 aberrations were common. The gene expression profile of IG/IRF4-positive lymphomas was different from other subtypes of DLBCL and a classifier for IG/IRF4 positivity containing 27 genes allowed prediction of 3 additional MMML IG/IRF4-positive cases subsequently proven by FISH. IG/IRF4-positivity was associated with a favorable outcome likely due to significant enrichment of IG/IRF4-positive lymphomas in childhood and young adulthood. Conclusions: Our results suggest IRF4 translocations to be primary genetic alterations in a novel molecularly defined subset of GC-derived lymphomas predominantly affecting children. 271 diffuse large B-Cell lymphoma samples were hybridized to HGU133A Affymetrix GeneChips.

2011-06-24 | E-GEOD-22470 | biostudies-arrayexpress

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