Divergent Mechanisms of Oncogenic B Cell Receptor Signaling in Lymphoma
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE99276 | GEO | 2018/05/01
REPOSITORIES: GEO
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Project description:Diffuse large B-cell lymphoma (DLBCL) is an aggressive cancer with two major biological subtypes, activated B-cell like (ABC) and germinal center B-cell-like (GCB) DLCBL. Self-antigen engagement of B-cell receptors (BCRs) in ABC tumors promotes their clustering in the plasma membrane, thereby initiating chronic active signaling and downstream activation of the pro-survival NF-kB and PI3 kinase pathways. The potential of therapeutics targeting chronic active BCR signaling in ABC DLBCL is highlighted by the frequent response of these tumors to inhibitors of BTK, a kinase that links BCR signaling to NF-kB activation. Here we used genome-wide CRISPR-Cas9 screens to identify regulators of the IRF4, a direct NF-kB target and essential transcription factor in ABC cells. Unexpectedly, inactivation of the oligosaccharyltransferase (OST) complex, which mediates N-linked protein glycosylation, reduced IRF4 expression and NF-kB activity in ABC cells, resulting in cell death. Using functional glycoproteogenomics we linked this phenomenon to defective BCR glycosylation. Pharmacologic inhibition of OST reduced the size and abundance of BCR microclusters in the plasma membrane and blocked their internalization. These reorganized BCRs associated with the inhibitory coreceptor CD22, which attenuated proximal BCR signaling, thereby reducing NF-kB and PI3 kinase activation. OST inhibition also blocked the trafficking of TLR9 to the endolysosomal compartment, preventing its association with the BCR in the My-T-BCR signaling complex that activates NF-kB in ABC cells. In GCB DLBCL, OST inhibition also attenuated constitutive BCR signaling, reducing PI3 kinase signaling and triggering cell death. Our data highlight the therapeutic potential of OST inhibitors for the treatment of diverse B cell malignancies in which constitutive BCR signaling is essential.
2023-04-24 | PXD038951 | Pride
Project description:Diffuse large B-cell lymphoma (DLBCL) is an aggressive cancer with two major biological subtypes, activated B-cell like (ABC) and germinal center B-cell-like (GCB) DLCBL. Self-antigen engagement of B-cell receptors (BCRs) in ABC tumors promotes their clustering in the plasma membrane, thereby initiating chronic active signaling and downstream activation of the pro-survival NF-B and PI3 kinase pathways. The potential of therapeutics targeting chronic active BCR signaling in ABC DLBCL is highlighted by the frequent response of these tumors to inhibitors of BTK, a kinase that links BCR signaling to NF-B activation. Here we used genome-wide CRISPR-Cas9 screens to identify regulators of the IRF4, a direct NF-kB target and essential transcription factor in ABC cells. Unexpectedly, inactivation of the oligosaccharyltransferase (OST) complex, which mediates N-linked protein glycosylation, reduced IRF4 expression and NF-B activity in ABC cells, resulting in cell death. Using functional glycoproteogenomics we linked this phenomenon to defective BCR glycosylation. Pharmacologic inhibition of OST reduced the size and abundance of BCR microclusters in the plasma membrane and blocked their internalization. These reorganized BCRs associated with the inhibitory coreceptor CD22, which attenuated proximal BCR signaling, thereby reducing NF-B and PI3 kinase activation. OST inhibition also blocked the trafficking of TLR9 to the endolysosomal compartment, preventing its association with the BCR in the My-T-BCR signaling complex that activates NF-B in ABC cells. In GCB DLBCL, OST inhibition also attenuated constitutive BCR signaling, reducing PI3 kinase signaling and triggering cell death. Our data highlight the therapeutic potential of OST inhibitors for the treatment of diverse B cell malignancies in which constitutive BCR signaling is essential.
2023-04-22 | PXD036363 | 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. To generate a gene expression signature of MYD88 signaling in ABC DLBCL, the HBL-1 cell line was transduced with retroviral vectors expressing either shMYD88-4 or shMYD88-7. Following puromycin selection, shRNA expression was induced for 24 or 48 hours and gene expression was measured, comparing uninduced (Cy3) to induced (Cy5) cells, using genome-wide Agilent 4x44K oligonucleotide microarrays. A signature of NF-kB signaling in ABC DLBCL was generated by treating HBL-1 cells with the IkB kinase beta inhibitor MLN120B for 2h, 3h, 4h, 6h, 8h, 12h, 16h, and 24h (Cy5), and comparing their gene expression to untreated cells (Cy3). A signature of JAK signaling in ABC DLBCL was generated by treating HBL-1 cells with JAK inhibitor I (5 micromolar; Calbiochem) for 2h, 4h, 6h, and 8h (Cy5) and comparing their gene expression to vehicle-treated cells (DMSO, Cy3). RNA-Seq data not provided.
2010-12-30 | E-GEOD-22900 | biostudies-arrayexpress
Project description:The activated B cell-like (ABC) subgroup of diffuse large B cell lymphoma (DLBCL) is characterized by constitutive activation of the NF-êB pathway. Here we show that the NF- êB pathway induces the expression of the cytokines IL-6 and IL-10 in ABC DLBCL cell lines, which also have high levels of total and phosphorylated STAT3 protein, suggesting autocrine signaling. Using RNA interference for STAT3, we defined a gene expression signature of IL-6 and IL-10 signaling through STAT3. Based on this signature, we constructed a molecular predictor of STAT3 signaling that defined a subset of ABC DLBCL tumors with high expression of STAT3, IL-6 and/or IL-10, and their downstream targets. Although the STAT3-high and STAT3-low subsets had equivalent expression of genes that distinguish ABC DLBCL from GCB DLBCL, STAT3-high ABC DLBCLs had higher expression of signatures that reflected NF-kB activity, proliferation, and glycolysis. A smallmolecule inhibitor of JAK signaling, which blocked STAT3 signature expression, was toxic only for ABC DLBCL lines, and synergized with an inhibitor of NF-kB signaling. These findings suggest that the biological interplay between the STAT3 and NF-kB pathways may be exploited for the treatments of a subset of ABC DLBCLs. Keywords: time series design
2007-12-21 | GSE10009 | GEO
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:Constitutive activation of the nuclear factor-kappa B (NF-kB) pathway is a hallmark of the activated B-cell-like (ABC) subtype of diffuse large B-cell lymphoma (DLBCL). Recurrent mutations of NF-kB regulators that cause constitutive activity of this oncogenic pathway have been identified. However, it remains unclear how specific target genes are regulated. We identified the IkB-like protein NFKBIZ that binds NF-kB subunits and enhances transactivation of some NF-kB target genes while repressing others, to be upregulated in ACB compared to GCB DLBCL primary patient samples (p=5.1 x 10^-37). Knockdown of NFKBIZ by RNA interference was toxic to ABC but not GCB DLBCL cell lines. Gene expression profiling following NFKBIZ knockdown significantly downregulated a large number of NF-kB target genes, suggesting a central role in regulating NF-kB signaling. To further investigate the molecular mechanisms of how NFKBIZ mediates NF-kB signaling in ABC DLBCL, we performed immunoprecipitations and detected an interaction of NFKBIZ with both p50 and p52 NF-kB subunits, indicating that both the canonical and non-canonical NF-kB pathways are regulated by NFKBIZ. Collectively, our data imply that NFKBIZ is required for NF-kB signaling in ABC DLBCL and thus might represent a promising molecular target for future therapies. The complete dataset is comprised of three experiments with the male HBL-1 ABC DLBCL cell line: a) 8 paired GEP measurements after NFKBIZ inhibition by shRNA, b) 6 paired GEP measurements after applying the MLN inhibitor and c) 4 two-color measurements after applying a MALT inhibitor. This dataset includes 4 two-color measurements of the male HBL-1 ABC DLBCL cell line after applying a MALT inhibitor.
2013-07-22 | E-GEOD-46973 | biostudies-arrayexpress
Project description:The activated B cell-like (ABC) subgroup of diffuse large B cell lymphoma (DLBCL) is characterized by constitutive activation of the NF-êB pathway. Here we show that the NF- êB pathway induces the expression of the cytokines IL-6 and IL-10 in ABC DLBCL cell lines, which also have high levels of total and phosphorylated STAT3 protein, suggesting autocrine signaling. Using RNA interference for STAT3, we defined a gene expression signature of IL-6 and IL-10 signaling through STAT3. Based on this signature, we constructed a molecular predictor of STAT3 signaling that defined a subset of ABC DLBCL tumors with high expression of STAT3, IL-6 and/or IL-10, and their downstream targets. Although the STAT3-high and STAT3-low subsets had equivalent expression of genes that distinguish ABC DLBCL from GCB DLBCL, STAT3-high ABC DLBCLs had higher expression of signatures that reflected NF-kB activity, proliferation, and glycolysis. A smallmolecule inhibitor of JAK signaling, which blocked STAT3 signature expression, was toxic only for ABC DLBCL lines, and synergized with an inhibitor of NF-kB signaling. These findings suggest that the biological interplay between the STAT3 and NF-kB pathways may be exploited for the treatments of a subset of ABC DLBCLs. Activated B cell-like (ABC) subgroup of diffuse large B cell lymphoma (DLBCL) cell lines were used as model systems to study the cytokine pathways in these cells. We expressed inducible IkB super-repressor for 1 to 24 hours to identify NF-kB target genes in OCI-Ly3 and OCI-Ly10 cells for a total of 13 arrays with replicates of each time point. We treated OCI-Ly3 cells with IL-10 for 1 to 96 hours for a total of 10 arrays with replicates of each time point. We treated OCI-Ly10 cells with IL-6 for 30 minutes to 24 hours for a total of 8 arrays with replicates of each time point. OCI-Ly10 cells transfected with no siRNA versus STAT3-siRNA for 8, 24, or 48 hours for a total of 5 arrays with replicates for 24 and 48 hours. We treated OCI-Ly10 cells with JAK inhibitor I for 3 and 6 hours for a total of 4 arrays with replicates of each time point.
2010-05-27 | E-GEOD-10009 | biostudies-arrayexpress
Project description:Constitutive activation of the nuclear factor-kappa B (NF-kB) pathway is a hallmark of the activated B-cell-like (ABC) subtype of diffuse large B-cell lymphoma (DLBCL). Recurrent mutations of NF-kB regulators that cause constitutive activity of this oncogenic pathway have been identified. However, it remains unclear how specific target genes are regulated. We identified the IkB-like protein NFKBIZ that binds NF-kB subunits and enhances transactivation of some NF-kB target genes while repressing others, to be upregulated in ACB compared to GCB DLBCL primary patient samples (p=5.1 x 10^-37). Knockdown of NFKBIZ by RNA interference was toxic to ABC but not GCB DLBCL cell lines. Gene expression profiling following NFKBIZ knockdown significantly downregulated a large number of NF-kB target genes, suggesting a central role in regulating NF-kB signaling. To further investigate the molecular mechanisms of how NFKBIZ mediates NF-kB signaling in ABC DLBCL, we performed immunoprecipitations and detected an interaction of NFKBIZ with both p50 and p52 NF-kB subunits, indicating that both the canonical and non-canonical NF-kB pathways are regulated by NFKBIZ. Collectively, our data imply that NFKBIZ is required for NF-kB signaling in ABC DLBCL and thus might represent a promising molecular target for future therapies. The complete dataset is comprised of three experiments with the male HBL-1 ABC DLBCL cell line: a) 8 paired GEP measurements after NFKBIZ inhibition by shRNA, b) 6 paired GEP measurements after applying the MLN inhibitor and c) 4 two-color measurements after applying a MALT inhibitor. This dataset includes 8 paired GEP measurements after NFKBIZ inhibition by shRNA.
2013-07-22 | E-GEOD-46971 | biostudies-arrayexpress
Project description:Constitutive activation of the nuclear factor-kappa B (NF-kB) pathway is a hallmark of the activated B-cell-like (ABC) subtype of diffuse large B-cell lymphoma (DLBCL). Recurrent mutations of NF-kB regulators that cause constitutive activity of this oncogenic pathway have been identified. However, it remains unclear how specific target genes are regulated. We identified the IkB-like protein NFKBIZ that binds NF-kB subunits and enhances transactivation of some NF-kB target genes while repressing others, to be upregulated in ACB compared to GCB DLBCL primary patient samples (p=5.1 x 10^-37). Knockdown of NFKBIZ by RNA interference was toxic to ABC but not GCB DLBCL cell lines. Gene expression profiling following NFKBIZ knockdown significantly downregulated a large number of NF-kB target genes, suggesting a central role in regulating NF-kB signaling. To further investigate the molecular mechanisms of how NFKBIZ mediates NF-kB signaling in ABC DLBCL, we performed immunoprecipitations and detected an interaction of NFKBIZ with both p50 and p52 NF-kB subunits, indicating that both the canonical and non-canonical NF-kB pathways are regulated by NFKBIZ. Collectively, our data imply that NFKBIZ is required for NF-kB signaling in ABC DLBCL and thus might represent a promising molecular target for future therapies. The complete dataset is comprised of three experiments with the male HBL-1 ABC DLBCL cell line: a) 8 paired GEP measurements after NFKBIZ inhibition by shRNA, b) 6 paired GEP measurements after applying the MLN inhibitor and c) 4 two-color measurements after applying a MALT inhibitor. This dataset includes 6 paired GEP measurements after applying the MLN inhibitor.
2013-07-22 | E-GEOD-46972 | biostudies-arrayexpress
Project description:Diffuse large B-cell lymphoma (DLBCL), the most common form of lymphoma in adulthood, comprises multiple biologically and clinically distinct subtypes including germinal center B cell-like (GCB) and activated B cell like (ABC) DLBCL. Gene expression profile studies have shown that its most aggressive subtype, ABC-DLBCL, is associated with constitutive activation of the NF-kB transcription complex. However, except for a small fraction of cases, it remains unclear whether NF-kB activation in these tumors represents an intrinsic program of the tumor cell of origin or a pathogenetic event. Here we show that >50% of ABC-DLBCL and a smaller fraction of GCB-DLBCL carry somatic mutations at multiple genes, including negative (TNFAIP3/A20) and positive (CARD11, TRAF2, TRAF5, MAP3K7/TAK1 and TNFRSF11A/RANK) regulators of NF-kB. Of these, the A20 gene, which encodes for a ubiquitin-modifying enzyme involved in termination of NF-kB responses, is the most commonly affected one, with ~30% of the patients displaying biallelic inactivation by mutations and/or deletions, suggesting a tumor suppressor role. Less frequently, missense mutations of TRAF2 and CARD11 produce molecules with significantly enhanced ability to activate NF-kB. Thus, our results demonstrate that NF-kB activation in DLBCL is caused by genetic lesions affecting multiple genes, whose loss or activation may promote lymphomagenesis by leading to abnormally prolonged NF-kB responses. We show that most ABC-DLBCL and a smaller fraction of GCB-DLBCL display genetic lesions affecting multiple NFkB pathway genes, with A20 representing the most frequently mutated gene Keywords: Phenotypic characterization of human DLBCL.
2009-04-10 | GSE12195 | GEO