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A mouse model of deregulation of the malt1 oncogene recapitulates the pathogenesis of human malt lymphoma [MALT dataset]

ABSTRACT: Attempts at modeling chromosomal translocations involving MALT1 gene, hallmarks of human mucosa-associated lymphoid tissue (MALT) lymphoma, have failed to reproduce the disease in mice. Here we describe a transgenic model in which MALT1 expression was targeted to mouse hematopoietic stem/progenitor cells. In Sca1-MALT1 mice, MALT1 deregulation activated the NF-kappaB pathway in Sca1+ cells, promoting selective B-cell differentiation and mature lymphocyte accumulation in extranodal tissues, progressively leading to the development of clonal B-cell lymphomas. These tumors recapitulated the histopathological features of human MALT lymphomas, presenting typical lymphoepithelial lesions and plasmacytic differentiation. Transcriptional profiling of Sca1-MALT1 murine lymphomas revealed overlapping molecular signatures with human MALT lymphomas, including MALT1-mediated NF-kappaB activation, pro-inflammatory signaling and XBP1-induced plasmacytic differentiation. Moreover, murine Malt1 showed proteolytic activity by cleaving Bcl10 in Sca1-MALT1 lymphomas. Our novel technological approach has allowed modeling human MALT lymphoma in mice, which represent unique tools study MALT lymphoma biology and evaluate anti-MALT1 therapies. Keywords: lymphoma profiling, MALT lymphoma

ORGANISM(S): Homo sapiens

PROVIDER: GSE25638 | GEO | 2012/07/10

SECONDARY ACCESSION(S): PRJNA142423

REPOSITORIES: GEO

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Project description:MALT lymphoma is characterized by t(11;18)(q21;q21)/API2-MALT1, t(1;14)(p22;q32)/BCL10-IGH and t(14;18)(q32;q21)/IGH-MALT1, which commonly activate the NF-ÎºB pathway. Gastric MALT lymphomas harboring such translocation do not respond to H. pylori eradication, while those without translocation can be cured by antibiotics. To understand the molecular mechanism of these different MALT lymphoma subgroups, we performed gene expression profiling analysis of 24 MALT lymphomas (15 translocation-positive, 9 translocation-negative). Gene set enrichment analysis (GSEA) of the NF-ÎºB target genes and 4394 additional gene sets covering various cellular pathways, biological processes and molecular functions showed that translocation-positive MALT lymphomas are characterized by an enhanced expression of NF-ÎºB target genes, particularly TLR6, CCR2, CD69 and BCL2, while translocation-negative cases were featured by active inflammatory and immune responses, such as IL8, CD86, CD28 and ICOS. Separate analyses of the genes differentially expressed between translocation-positive and negative cases and measurement of gene ontology term in these differentially expressed genes by hypergeometric test reinforced the above findings by GSEA. Finally, expression of TLR6, in the presence of TLR2, enhanced both API2-MALT1 and BCL10 mediated NF-ÎºB activation in vitro. Our findings provide novel insights into the molecular mechanism of MALT lymphomas with and without translocation, potentially explaining their different clinical behaviors. This study compares MALT with other lymphomas, namely follicular lymphomas (FL) and mantle cell lymphomas (MCL), and investigates the molecular mechanisms of the lymphomagenesis between translocation-positive versus -negative MALT lymphoma cases in order to derive the pathways leading to MALT lymphoma pathogenesis. The study uses fresh frozen tissues from 24 MALT lymphoma cases with 7 FL and 7 MCL. Samples were run on the HG-U133A, HG-U133B, and HG-U133 plus2 GeneChips.

Project description:MALT lymphoma is characterized by t(11;18)(q21;q21)/API2-MALT1, t(1;14)(p22;q32)/BCL10-IGH and t(14;18)(q32;q21)/IGH-MALT1, which commonly activate the NF-κB pathway. Gastric MALT lymphomas harboring such translocation do not respond to H. pylori eradication, while those without translocation can be cured by antibiotics. To understand the molecular mechanism of these different MALT lymphoma subgroups, we performed gene expression profiling analysis of 24 MALT lymphomas (15 translocation-positive, 9 translocation-negative). Gene set enrichment analysis (GSEA) of the NF-κB target genes and 4394 additional gene sets covering various cellular pathways, biological processes and molecular functions showed that translocation-positive MALT lymphomas are characterized by an enhanced expression of NF-κB target genes, particularly TLR6, CCR2, CD69 and BCL2, while translocation-negative cases were featured by active inflammatory and immune responses, such as IL8, CD86, CD28 and ICOS. Separate analyses of the genes differentially expressed between translocation-positive and negative cases and measurement of gene ontology term in these differentially expressed genes by hypergeometric test reinforced the above findings by GSEA. Finally, expression of TLR6, in the presence of TLR2, enhanced both API2-MALT1 and BCL10 mediated NF-κB activation in vitro. Our findings provide novel insights into the molecular mechanism of MALT lymphomas with and without translocation, potentially explaining their different clinical behaviors. This study compares MALT with other lymphomas namely follicular and mantle cell lymphomas, and investigates the molecular mechanisms of the lymphomagenesis between translocation positive versus negative MALT lymphoma cases in order to derive the pathways leading to MALT lymphoma pathogenesis using GSEA, GO, dynamic pathway analysis as well as other bioinformatics analysis. Samples were run on the Affymetrix HG-U133A and HG-U133 plus2 GeneChips.

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A mouse model of deregulation of the malt1 oncogene recapitulates the pathogenesis of human malt lymphoma [MALT dataset]

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