Pre-neoplastic somatic mutations including MYD88L265P in lymphoplasmacytic lymphoma
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ABSTRACT:
PROVIDER: EGAS00001005656 | EGA |
REPOSITORIES: EGA
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Project description:Normal-cell counterparts of solid and myeloid tumors accumulate mutations years before disease onset; whether this occurs in B-lymphocytes prior to lymphoma remains uncertain. We sequenced multiple stages of the B-lineage in elderly individuals and patients with lymphoplasmacytic lymphoma, a singular disease for studying lymphomagenesis because of high-prevalence of mutated MYD88. We observed similar accumulation of random mutations in B-lineages from both cohorts and, unexpectedly, found MYD88L265P in normal precursor and mature B-lymphocytes from lymphoma patients. We uncovered genetic and transcriptional pathways driving malignant transformation and leveraged these to model lymphoplasmacytic lymphoma in mice, based on mutated MYD88 in B-cell precursors and BCL2 overexpression. Thus, MYD88L265P is a pre-neoplastic event, which challenges current understanding of lymphomagenesis and may have implications for early detection of B-cell lymphomas.
2021-11-04 | GSE185156 | GEO
Project description:Normal-cell counterparts of solid and myeloid tumors accumulate mutations years before disease onset; whether this occurs in B-lymphocytes prior to lymphoma remains uncertain. We sequenced multiple stages of the B-lineage in elderly individuals and patients with lymphoplasmacytic lymphoma, a singular disease for studying lymphomagenesis because of high-prevalence of mutated MYD88. We observed similar accumulation of random mutations in B-lineages from both cohorts and, unexpectedly, found MYD88L265P in normal precursor and mature B-lymphocytes from lymphoma patients. We uncovered genetic and transcriptional pathways driving malignant transformation and leveraged these to model lymphoplasmacytic lymphoma in mice, based on mutated MYD88 in B-cell precursors and BCL2 overexpression. Thus, MYD88L265P is a pre-neoplastic event, which challenges current understanding of lymphomagenesis and may have implications for early detection of B-cell lymphomas.
2021-11-04 | GSE185157 | GEO
Project description:In this study, we used a doxycycline (DOX) inducible gene expression system to introduce MyD88, a gene associated with lymphoma, into the U2932 lymphoma cell line. We performed a transcriptomic analysis (RNA-seq) to identify differentially expressed genes due to the MyD88 L265P oncogenic mutation. This study aimed to investigate the impact of MyD88 L265P oncogenic signaling on lymphoma cells by analyzing the transcriptomic response of model cell lines.
2023-06-06 | GSE226797 | GEO
Project description:Aberrant B-cell receptor (BCR)/NF-kB signaling activity is a prominent feature of diffuse large B-cell lymphoma (DLBCL), particularly of, but not restricted to the activated B-cell (ABC) subtype. Recurrent mutations in this cascade, e.g. in CD79B, CARD11, A20/TNFAIP3 or NFKBIZ, but also in the Toll-like receptor (TLR) pathway transducer MyD88, all converge at NF-kB deregulation, but their differential impact on lymphoma development and biology remains to be dissected. Recapitulating oncogenic myc rearrangements as another common feature of DLBCL, we functionally investigate here primary mouse lymphomas that formed after propagation of Eµ-myc transgenic hematopoietic stem cells (HSC), stably transduced with naturally occurring DLBCL-derived NF-kB mutants, in recipient mice. While most mutants tested supported Myc-driven lymphoma formation through repressed apoptosis, selectively deregulated CARD11- or MyD88-mutant lymphoma cells presented with a macrophage-activating secretion profile, which, in turn, enforced TGF-b-mediated feedback senescence in the lymphoma cell compartment. Moreover, MyD88- or CARD11-mutant Eµ-myc lymphomas – mirrored by matching signatures in their mutant DLBCL counterparts – exhibited high-level expression of the immune checkpoint mediator PD-L1, thus preventing their efficient clearance by adaptive host cell immunity. Conversely, these mutant-specific dependencies were therapeutically exploitable by anti-PD1 immune checkpoint blockade, leading to the direct T-cell-mediated lysis of predominantly but not exclusively senescent lymphoma cells. Our functional, cross-species interrogation of a syngeneic and fully immune-competent, BCR/NF-kB-deregulated and DLBCL-reminiscent in vivo-model platform unveils common principles and therapeutic vulnerabilities related to human DLBCL subsets that will inform future personalized treatment strategies.
2020-12-07 | GSE141452 | GEO
Project description:Pre-neoplastic somatic mutations including MYD88L265P in lymphoplasmacytic lymphoma
| PRJNA767837 | ENA
Project description:Many lymphoid malignancies arise from deregulated c-MYC expression in cooperation with additional genetic lesions. While many of these cooperative genetic lesions have been discovered and their functions characterised, DNA sequence data of primary patient samples suggest that many more do exist. However, the nature of their contributions to c-MYC driven lymphomagenesis have not yet been investigated. We identified TFAP4 as a potent suppressor of c-MYC driven lymphoma development in a previous genome-wide CRISPR knockout screen in primary cells in vivo. CRISPR deletion of TFAP4 in Eµ-MYC transgenic haematopoietic stem and progenitor cells (HSPCs) and transplantation of these manipulated HSPCs into lethally irradiated animals significantly accelerated c-MYC-driven lymphoma development. Interestingly, TFAP4 deficient Eµ-MYC lymphomas all arose at the pre-B cell stage of B cell development. This observation prompted us to characterise the transcriptional profile of pre-B cells from pre-leukaemic mice transplanted with Eµ-MYC/Cas9 HSPCs that had been transduced with sgRNAs targeting TFAP4. This analysis revealed that TFAP4 deletion reduced expression of several master regulators of B cell differentiation, such as Spi1, SpiB and Pax5, which are direct target genes of both TFAP4 and MYC. We therefore conclude that loss of TFAP4 leads to a block in differentiation during early B cell development, thereby accelerating c-MYC-driven lymphoma development.
2023-03-12 | GSE225684 | GEO
Project description:The MEF2B transcription factor is frequently mutated in germinal center (GC)-derived B-cell lymphomas. Its N-terminal mutations drive lymphomagenesis by escaping interaction with transcriptional repressors, while the function of C-terminal mutations remains to be elucidated. Here, we show that MEF2B C-tail is physiologically phosphorylated at specific residues and phosphorylation at S324 is impaired by lymphoma-associated mutations. Lack of phosphorylation at S324 enhances the interaction of MEF2B with the SWI/SNF chromatin remodeling complex, leading to higher transcriptional activity. In addition, these mutants show an increased protein stability due to impaired interaction with the CUL3/KLHL12 ubiquitin complex. Mice expressing a phosphorylation-deficient lymphoma-associated MEF2B mutant display GC enlargement and develop GC-derived lymphomas, when crossed with Bcl2 transgenic mice. These results unveil converging mechanisms of action for a diverse spectrum of MEF2B mutations, all leading to its dysregulation and GC B-cell lymphomagenesis. These assorted mechanisms provide additional opportunities for the development of targeted therapeutic approaches.
2024-08-26 | PXD043998 | Pride
Project description:The ABC subtype of diffuse large B cell lymphoma (DLBCL) remains the least curable form of this lymphoma despite recent advances in therapy. We have combined structural and functional genomics to triangulate on new oncogenic mechanisms and devise new therapeutic strategies. RNA interference screen revealed a dependence of ABC DLBCL cell lines on MYD88 and IRAK1. High throughput resequencing of RNA (RNA-Seq) revealed frequent somatic mutations in MYD88 that preferentially occurred in the ABC DLBCL subtype. Remarkably, one third of ABC DLBCL tumor samples harbored the same amino acid substitution, L265P, in the MYD88 TIR domain at an evolutionarily invariant residue in its hydrophobic core. This mutation was rare or absent in two other DLBCL subtypes, but was observed in 9% of MALT lymphomas. At a lower frequency, multiple other mutations were observed in the MYD88 TIR domain, occurring in both the ABC and GCB subtypes of DLBCL. Survival of ABC DLBCL lines bearing the L265P mutation was sustained by the mutant but not wild type MYD88 isoform, demonstrating that this MYD88 mutant is oncogenic and gain-of-function. The MYD88 L265P mutant assembled a protein complex that spontaneous triggers the phosphorylation of IRAK1, leading to NF-kB signaling, secretion of the cytokines IL-6, IL-10 and interferon-b, and JAK kinase signaling. These findings demonstrate that the MYD88 signaling pathway is integral to the pathogenesis of ABC DLBCL, providing a genetic rationale for therapeutic targeting of the MYD88 signaling pathway in this lymphoma subtype.
2010-12-30 | GSE22900 | GEO
Project description:BTG1 is recurrently mutated in the MCD/C5 subgroup of diffuse large B cell lymphoma (DLBCL), but the functions of this gene in lymphomagenesis have never been investigated so far. Here we provide evidence that Btg1 knock out accelerates the development of a lethal lymphoproliferative disease driven by Bcl2 overexpression. Exploring the clinical association between BTG1 mutation and extranodal dissemination, we discovered BCAR1 as a new BTG1 partner. Following BTG1 inactivation, overactivation of the BCAR1-RAC1 pathway induced major remodeling of the actin cytoskeleton and increased migration capacities of lymphoma cells in vitro and in vivo. These modifications were targetable with the SRC inhibitor dasatinib, which opens interesting clinical perspectives in BTG1 mutated DLBCL
2022-03-10 | MSV000089045 | MassIVE
Project description:Pre-neoplastic somatic mutations including MYD88L265P in lymphoplasmacytic lymphoma [WES]
| PRJNA767843 | ENA