scholarly journals Critical Role of B Cell Lymphoma 10 in BAFF-Regulated NF-κB Activation and Survival of Anergic B Cells

2012 ◽  
Vol 189 (11) ◽  
pp. 5185-5193 ◽  
Author(s):  
Mei Yu ◽  
Yuhong Chen ◽  
Yinghong He ◽  
Andrew Podd ◽  
Guoping Fu ◽  
...  
Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 3805-3805
Author(s):  
Jorge Contreras ◽  
Jayanth Kumar Palanichamy ◽  
Tiffany Tran ◽  
Dinesh S. Rao

Abstract Diffuse large B cell lymphoma (DLBCL) is one of the most common Non-Hodgkin lymphomas among adults. It is a heterogeneous disease characterized by multiple mutations and translocations. Gene expression profiling studies have revealed several characteristic gene expression patterns, with two main patterns emerging, namely Germinal Center(GC) type, and Activated B Cell (ABC) type. ABC-type DLBCL shows gene expression patterns that resemble activated B-cells, with increased expression of anti-apoptotic, and pro-proliferative genes. Critically, upregulation of the NF-κB the pathway is a hallmark of ABC-type DLBCL and has been shown to be necessary for survival, and is caused by several different mutations at different levels within the pathway. Recent work has revealed the critical importance of a new class of small RNA molecules, namely microRNAs, in gene regulation. Of these, microRNA-146a (miR-146a) was discovered as an NF-κB induced microRNA that plays a role as a negative feedback regulator of this pathway by targeting adaptor proteins. To further characterize miR-146a, mice deficient for this miRNA were created, and were found to develop lymphadenopathy, splenomegaly, and myeloid proliferation. As expected, immune cells in these mice have an upregulated NF-κB pathway and many of the phenotypes can be ameliorated by inhibition of the NF-κB pathway. Importantly, a significant proportion of the animals develop B-cell lymphoma at older ages. In this study, we examined the role of miR-146a in the development of malignancy in B-cells. To accelerate the role of miR-146a in tumor formation we overlaid the miR-146a deficient allele onto the Eμ-Myc like mouse model. Eμ-Myc mice develop tumors on average by 14weeks of age. The transgenic status of animals was verified by genotyping, RNA and protein expression analyses. miR-146a sufficient and deficient animals on the Eμ-Myc background were followed for tumor latency by peripheral blood analysis and careful physical examination. Based on approved humane criteria for animal discomfort, animals were sacrificed and hematopoietic tissue was harvested for analysis. Mice deficient for miR-146a had a statistically reduced survival in comparison with miR-146a sufficient animals with a p-value of .0098 (Kaplan Meir survival analysis). Complete Blood Count of animals at time of death revealed an increase leukemia presentation in the miR-146a deficient background. FACS analysis of tumor tissue from both groups revealed an increase in the number of IgM positive tumors in the miR-146a-deficient background indicating skewing towards more mature B cell neoplasms when miR-146a is lacking. Lineage analysis of tumors verified them to be of B cell origin although a subset of miR-146a sufficient tumors had higher numbers of infiltrating myeloid cells compared to deficient animals. Furthermore, histologic analysis of hematopoietic organs showed that while infiltration remained similar in kidneys and liver, more spleens in the miR-146a deficient background tended to be less involved. Our extensive histopathologic and immunophenotypic analyses indicate that miR-146a deficiency drives a more aggressive malignant phenotype in the B-cell lineage. In keeping with this, our profiling studies of human DLBCL suggest that a subset of DLBCL show decreased expression of miR-146a. We are currently examining the status of NF-κB in the murine tumors and using high throughput sequencing approaches to delineate gene expression differences between miR-146a sufficient and deficient tumors. We anticipate the discovery of novel gene targets of miR-146a and expect that these studies will lead to improved diagnostic and therapeutic options for patients of B-cell malignancies. Disclosures: No relevant conflicts of interest to declare.


2018 ◽  
Author(s):  
Christelle Vincent-Fabert ◽  
Alexis Saintamand ◽  
Amandine David ◽  
Mehdi Alizadeh ◽  
François Boyer ◽  
...  

AbstractTransformation of an indolent B-cell lymphoma is associated with a more aggressive clinical course and poor survival. The role of immune surveillance in the transformation of a B-cell indolent lymphoma towards a more aggressive form is poorly documented. To experimentally address this question, we used the L.CD40 mouse model, which is characterized by B-cell specific continuous CD40 signaling, responsible for spleen indolent clonal or oligoclonal B-cell lymphoma after one year in 60% cases. Immunosuppression was obtained either by T/NK cell depletion or by treatment with the T-cell immunosuppressive drug cyclosporin A. Immunosuppressed L.CD40 mice had larger splenomegaly with increased numbers of B-cells in both spleen and peripheral blood. High-throughput sequencing of immunoglobulin variable segments revealed that clonal expansion was increased in immunosuppressed L.CD40 mice. Tumor B cells of immunosuppressed mice were larger with an immunoblastic aspect, both on blood smears and spleen tissue sections, with increased proliferation rate and increased numbers of activated B-cells. Collectively, these features suggest that immune suppression induced a shift from indolent lymphomas into aggressive ones. Thus, as a preclinical model, immunosuppressed L.CD40 mice reproduce aggressive transformation of an indolent B-cell tumor and highlight the role of the immune surveillance in its clinical course, opening new perspective for immune restoration therapies.Summary statementHighlighting the role of immune surveillance, transformation of indolent B-cell lymphoma into an aggressive malignancy is experimentally reproduced after T-cell immune suppression in the L.CD40 preclinical mouse model.


Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 397-397
Author(s):  
Xiwen Gu ◽  
Carmen J. Booth ◽  
David G. Schatz ◽  
Matthew P. Strout

Abstract Abstract 397 Upon antigenic stimulation of B cells, germinal centers (GCs) are formed where somatic hypermutation (SHM) and class switch recombination (CSR) of immunoglobulin (Ig) genes serve to diversify the immune response. SHM and CSR are initiated by the enzyme activation induced cytidine deaminase (AID) through the conversion of C/G base pairs to U-G mismatches. These mismatches are processed by UNG-dependent base excision repair (BER) and MSH2-dependent mismatch repair (MMR) pathways to yield mutations (for SHM) and DNA strand lesions (for CSR). Despite this essential role in immune diversification, the intrinsic activity of AID as a DNA mutator poses a threat to genomic integrity. Indeed, aberrant targeting of AID activity is associated with translocations and point mutations of proto-oncogenes associated with B cell malignancies. A specific dependence on AID in the pathogenesis of lymphomas of GC B cell origin is exemplified in Iμ-Bcl6 knock-in mice. These mice develop a diffuse large B cell lymphoma (DLBL) that resembles the human disease but are protected from development of this lymphoma when crossed onto an Aid-deficient background. To investigate the role of Aid-associated DNA repair in the pathogenesis of this disease, we crossed Iμ-Bcl6 mice onto a background deficient in BER (Ung−/−) and MMR (Msh2−/−). Young healthy Iμ-Bcl6 and Iμ-Bcl6 Ung−/−Msh2−/− mice displayed a normal number and distribution of B cells and normal architecture of lymphoid organs. Five of 28 Iμ-Bcl6 mice (17.9%) became sick starting at ∼12 months of age. Historically, median survival in these mice has not been reached and ∼80% survive to 15 months. In contrast, 21 of 28 Iμ-Bcl6 Ung−/−Msh2−/−mice (75%) developed disease with an onset of ∼3 months and had a median survival of 6.2 months (p<0.0001). All 5 of the Iμ-Bcl6 mice and the majority of Iμ-Bcl6 Ung−/−Msh2−/−mice developed B cell lymphoma with splenic involvement and variable nodal involvement. Five of the Iμ-Bcl6 Ung−/−Msh2−/−mice developed other cancers (3 T cell lymphomas, 1 pre-B cell lymphoma and 1 colon adenocarcinoma). Tumors from both genotypes expressed a mature B cell phenotype (B220+ IgM+ Igκ+ CD138-) and morphology revealed loss of normal lymphoid architecture with infiltration by lymphoid blasts. Additional staining demonstrated expression of at least one GC marker (Fas, GL7 and/or PNA). Similar to Iμ-Bcl6 mice, while many of the Iμ-Bcl6 Ung−/−Msh2−/−tumors had clonal mutated Ig heavy chain gene variable regions, two of the tumors were identified as oligoclonal, suggesting a preceding lymphoproliferative stage. In the absence of Ung and Msh2, Aid-generated U-G mismatches are not recognized and are simply replicated, causing only C/G to T/A transition mutations and no strand lesions. Thus, as expected, all Ig mutations in Iμ-Bcl6 Ung−/−Msh2−/−mice were C/G to T/A transitions. Lymphomas from Iμ-Bcl6 mice have been found to harbor numerous chromosome translocations and aneuploidies. Although additional analyses are underway, spectral karyotyping of 3 Iμ-Bcl6 Ung−/−Msh2−/−tumors revealed 2 with normal cytogenetics and 1 with a 40–41,XX,t(2;17),+15,+19. Surprisingly, sequence analysis of several known Aid target genes (cMyc, Pim1, RhoH, Pax5, Cd79a, Fas, H2ax and OcaB) in tumors from 3 Iμ-Bcl6 Ung−/−Msh2−/− mice did not identify any clonal mutations. However, non-clonal C/T to T/A transition mutations in cMyc were present at a frequency of 1.2 × 10−4, suggestive of ongoing Aid activity. The presence of Aid activity but absence of off-target Aid-mediated clonal SHM suggests that either other genes are targeted by Aid or that Aid has a secondary role in lymphomagenesis such as epigenetic reprogramming, as has been shown in iPS cells. Nonetheless, the incidence of Aid-dependent lymphomagenesis in the absence of Aid-associated DNA repair is significantly increased and the latency is greatly shortened. Altogether, this data suggests that Aid-associated BER and MMR pathways afford a protective effect against the development of Aid-dependent GC B cell lymphomas such as DLBL. To investigate the role of the individual Aid-associated DNA repair pathways, we have also generated Iμ-Bcl6 Ung−/− and Iμ-Bcl6 Msh2−/− single knockout mice. These studies are ongoing but preliminary results suggest that while the effect of Ung and Msh2 deficiency on lymphomagenesis may be synergistic, Msh2 might play a more critical role in preventing Aid-mediated genomic instability. Disclosures: No relevant conflicts of interest to declare.


Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 2702-2702
Author(s):  
Bridget Charbonneau ◽  
Alice H Wang ◽  
Anne J. Novak ◽  
Stephen M. Ansell ◽  
Andrew L. Feldman ◽  
...  

Abstract Abstract 2702 Background: CXCR5 [chemokine (C-X-C motif) receptor 5; also known as Burkitt lymphoma receptor 1 (BCR1)] is expressed on mature B-cells, subsets of CD4+ and CD8+ T-cells, and skin-derived migratory dendritic cells. CXCL13 is the ligand for CXCR5, and together they are involved in guiding B-cells into the B-cell zones of secondary lymphoid organs as well as T-cell migration. CXCR5 is also expressed in malignant cells in NHL patients. Single nucleotide polymorphisms (SNPs) in CXCR5 have not been extensively studied, although two studies reported that SNPs from this chromosome 11 gene were associated with risk of primary biliary cirrhosis in a European population and with risk of NHL in an Asian population. This study evaluated the role of common germline genetic variation in the risk and prognosis of the common NHL subtypes of diffuse large B-cell lymphoma (DLBCL), follicular lymphoma (FL), mantle cell lymphoma (MCL), marginal zone lymphoma (MZL) and peripheral T-cell lymphoma (PTCL). Methods: Ten SNPs in CXCR5 were genotyped using a clinic-based study of 2694 NHL cases (including 586 DLBCL, 588 FL, 137 MCL, 230 MZL, and 158 PTCL) and 1521 controls enrolled from 2002–2009 in the Molecular Epidemiology Resource of the University of Iowa/Mayo Clinic Lymphoma SPORE. Clinical data were abstracted for all NHL patients and all were prospectively followed for disease progression, retreatment, transformation and death. SNPs were selected from HapMap using a standard tagging approach (r2≥0.80 and minor allele frequency (MAF) ≥0.05) and included SNPs 5kb upstream and downstream from the gene. Genotyping was conducted using a custom Illumina iSelect panel. All SNPs were in Hardy-Weinberg equilibrium in the control group. The most prevalent homozygous genotype was used as the reference group, and each SNP was modeled as having a log-additive effect in the regression model. For risk of NHL, odds ratios (ORs) and 95% confidence intervals were calculated using unconditional logistic regression, adjusted for age and gender. For prognosis, hazard ratios (HR) were calculated for both event-free (EFS) and overall (OS) survival using Cox proportional hazards regression, adjusting for age, treatment type, and IPI (DLBCL, PTCL), FLIPI (FL), or MIPI (MCL). To determine risk of FL transformation to DLBCL, a competing risk Cox model was used. A p<0.05 was declared as statistically significant. Results: Of the 10 CXCR5 tag SNPs in our study, 5 were associated with risk of NHL, with rs1790192 (MAF=0.39 among controls) having the strongest association (OR=1.19, 95%CI 1.08–1.30; p=0.0003). This SNP was strongly associated with FL (OR=1.44, 95%CI 1.25–1.66; p=3.1×10−7), and was also associated with DLBCL (OR=1.16, 95%CI 1.01–1.33; p=0.038) and PTCL (OR=1.29, 95%CI 1.02–1.64; p=0.037) but not MCL or MZL. For FL, none of the SNPs were associated with EFS or OS, although rs1790192 was associated with better outcome among FL patients that were observed (HR=0.64; 95%CI 0.47–0.87; p=0.0039). For DLBCL, none of the SNPs were associated with EFS, while three SNPs were associated with OS: rs523604 (HR=0.79; 95%CI 0.64–0.97; p=0.028), rs12363277 (HR=0.57; 95%CI 0.33–0.99; p=0.046), and rs3922 (HR=0.79; 95%CI 0.65–0.97; p=0.027). The latter SNP was also associated with risk of transformation from FL to DLBCL (HR=0.61; 95%CI 0.40–0.91; p=0.016). For MCL, MZL and PTCL, none of the SNPs were associated with either EFS or OS. Conclusions: Several germline CXCR5 polymorphisms were associated with NHL risk, particularly rs1790192 with risk of FL as well as DLBCL and PTCL. CXCR5 SNPs did not appear to be important in prognosis for most NHL subtypes, although rs1790192 was associated with a better outcome in untreated FL and rs3922 was associated with OS in DLBCL patients and with risk of FL transformation. These results provide additional evidence for a role of host genetic variation in CXCR5 in lymphomagenesis, mainly in risk of disease development, although there may also be a role for CXCR5 in FL and DLBCL prognosis. Replications of these findings in additional studies are needed. Disclosures: Ansell: Seattle Genetics, Inc.: Research Funding.


Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 1364-1364
Author(s):  
Fazila Asmar ◽  
Jesper Christensen ◽  
Jens V Johansen ◽  
Anders Blåbjerg ◽  
Anja Pedersen ◽  
...  

Abstract Abstract 1364 Introduction: Cytosine methylation (mC) is a major DNA modification in higher eukaryotic genomes, which is involved in transcriptional silencing. A large amount of data has shown that patterns of DNA methylation are perturbed in hematological cancers including diffuse large B-cell lymphoma (DLBCL). The discovery that the TET hydroxylases convert mC to hydroxymethylcytosine (hmC) is a major break through for our understanding of how DNA methylation is deregulated. Multiple reports describe TET2 (Ten-Eleven Translocation 2) loss-of-function mutations in myeloid malignancies, and a recent study shows that TET2 inactivation perturbs both myeloid and lymphoid development in the mouse, and identifies TET2 mutations in ∼2% of human B-cell lymphoma (Quivoron et al, Cancer Cell 20, 1–14, 2011). Aims: In the present study our aims are to determine the frequency and clinical impact of TET2 mutations in DLBCL, to identify TET2 target genes in CD34+ cells, normal- and malignant B-cells, and evaluate the role of TET2 mutations on the methylation pattern at TET2 targets genes in normal and malignant hematopoiesis. Methods: DNA was isolated from fresh frozen DLBCL (n=110), normal CD34+ cells and B-cells, and a TET2 mutant DLBCL-cell line. Mutation scanning was performed by denaturing gradient gel electrophoresis (DGGE) and automated sequencing. Global methylation profiling was done by Illumina Infinium microarrays, methylation at individual genes by methylation specific melting curve analysis and pyrosequencing. Global mC and hmC patterns were determined by DNA immunoprecipitation and promoter array analysis in cell lines, B-cells and CD34+ cells. TET2 target genes were identified by ChIP followed by deep sequencing. Gene expression by Nimblegen custom made arrays and RT-qPCR. Results: We identified TET2 mutations in 15% of primary diffuse DLBCL, including missense mutation in the catalytic domain (n=8, 2 of which showed allelic loss), loss-of-function mutations (n=7, one of which showed allelic loss), and missense mutation outside the catalytic domain (n=1 with allelic loss). Somatic origin of these mutations was verified in 11 of the 16 cases where matched normal tissue was available. No difference in overall survival was observed between TET2mut and TET2wt cases (P=0.17). To a large extent, the TET2 targets genes identified by ChIP seq analysis were overlapping in CD34+ cells, normal- and malignant B-cells. Gene ontology analysis showed that TET2 target genes are mainly involved in DNA metabolism and repair, metabolic processes and cell cycle homeostasis. Global methylation in TET2mut and TET2wt cases and gene expression data are being analyzed in DLBCL samples. In addition, the distribution patterns of hmC and mC at TET2 target genes and the relation to gene expression is being analyzed in a TET2 mutant DLBCL cell line, normal B-cells and CD34+ cells. Conclusion and further analyses: Here, we show that TET2 mutations are frequent in DLBCL, and identify the TET2 target genes in CD34+ cells, and in normal and malignant B-cells. The role of TET2 mutations for global methylation and for the methylation patterns at TET2 target genes will be presented at the meeting. By investigating the clinical implications of TET2 mutations we aim to identify DLBCL subsets that may benefit from hypomethylating therapy. Furthermore, the identification of hypermethylated TET2 target genes will hopefully contribute to molecular understanding of how TET2 mutations induces malignant transformation. Disclosures: Christensen: EpiTherapeutics: cofounder of EpiTherapeutics and have shares and warrants in the company. Helin:EpiTherapeutics: cofounder of EpiTherapeutics and have shares and warrants in the company.


2015 ◽  
Vol 45 (9) ◽  
pp. 2593-2601 ◽  
Author(s):  
Lena Belting ◽  
Nadine Hömberg ◽  
Margarethe Przewoznik ◽  
Christoph Brenner ◽  
Tanja Riedel ◽  
...  

2019 ◽  
Vol 17 (1) ◽  
Author(s):  
Lin Zhu ◽  
Chunyan Xia ◽  
Lin Wu ◽  
Yuxuan Zhang ◽  
Junling Liu ◽  
...  

2007 ◽  
Vol 82 (3) ◽  
pp. 567-575 ◽  
Author(s):  
Chris G. Mueller ◽  
Charlotte Boix ◽  
Wing-Hong Kwan ◽  
Cécile Daussy ◽  
Emilie Fournier ◽  
...  

2016 ◽  
Vol 4 (4) ◽  
pp. 337-344 ◽  
Author(s):  
Haiying Wang ◽  
Aihong Wang ◽  
Zhenbo Hu ◽  
Xin Xu ◽  
Zhiqiang Liu ◽  
...  

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 3676-3676
Author(s):  
Herve Ghesquieres ◽  
Fabrice Jardin ◽  
Sophie Pallardy ◽  
Aurélie Verney ◽  
Anne Laure Borrel ◽  
...  

Abstract Abstract 3676 Background: Diffuse Large B-cell Lymphoma (DLBCL) is a heterogeneous disease based on biological analyses of tumor cells, with for instance the determination of two molecular subgroups, one with a profile close to germinal center B-cells and the second to activated B-cells. Data from the biology of tumor microenvironment could also be helpful to define different prognostic subgroups of DLBCL. The role of the biology of the patient with DLBCL, i.e. the host-related factors is little explored. Epidemiological studies showed that some inherited genetic variation in immune genes could increase the risk of lymphoma development and some retrospective studies indicated that patient's outcome could be predicted by some germ line polymorphisms (SNPs) in cytokine genes. The aim of this study is to determine the prognostic impact of 13 SNPs in 7 immune genes, IL10 (4 SNPs), Tumor Necrosis factor α (TNFA), lymphotoxin α (LTA), BAFF (3 SNPs), IL1A, IL8RB, IL4R (2 SNPs) in a cohort of newly diagnosed DLBCL patients included in the GELA LNH2003 prospective trials all treated by rituximab combined with chemotherapy. Patients and Methods: 1564 patients from France, Switzerland and Belgium were included in the 5 prospective multicentric trials of the LNH2003 program of the GELA designed for DLBCL patients who were stratified in different subgroups based on age and International Prognostic Index (IPI) score. A sample of peripheral blood lymphocytes was collected before treatment from 760 patients who signed a specific consent form for this genetic study. After pathologic review and exclusion of patients not receiving rituximab (48 patients), 554 DLBCL patients were available for this study. SNPs were genotyped using a TaqMan® based assay. Results: The median age of the 554 patients was 61 years (range, 18–93 years), 57% of them were male and 50% of patients presented at diagnosis a 2–3 age-adjusted IPI score. Chemotherapy regimen consisted in a combination of rituximab with CHOP-21 (110 patients, 20%), CHOP-14 (181 patients, 33%), low dose CHOP for patients older than 80 years (60 patients, 11%), or ACVBP regimen (203 patients, 36%). At the end of treatment, complete response (CR) or unconfirmed CR was observed in 75% of patients. After a median follow-up of 38 months, the 3-year progression free survival (PFS) and overall survival (OS) was 70.2% and 75.7%, respectively. All the polymorphism distributions of the SNPs analyzed were consistent with Hardy-Weinberg equilibrium. The main initial clinical characteristics of patients were not different according to the 13 studied SNPs, except for IL4R (rs2107356), CC carriers presented less frequently B symptoms than CT and TT carriers (28% vs. 41% and 61%, P = .01). No correlation was observed between the quality of the response at the end of the treatment and each genotype of the 13 studied SNPs. The 3-year PFS and OS were overall not influenced by the genotyping of the 13 SNPs. However, a trend for a better 3-year PFS for LTA +252GG carriers compared to LTA +252AG and AA carriers was observed (79.7% vs. 64.6% and 72.7%, P = .04). Conclusions: To our knowledge, this is the largest prospective multicentric study that investigates the role of immune SNPs on treatment response and outcome in a large cohort of newly diagnosed patients with DLBCL receiving rituximab. No correlation between SNPs and treatment response was observed. Analyses of the impact on outcome of each individual SNP showed only a trend for a prognostic role on PFS of LTA A252G SNP, which is already described as a functional SNP. The results will be further precise by the correlation of IL10, BAFF and TNFA /LTA full haplotypes with response and outcome. Disclosures: No relevant conflicts of interest to declare.


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