The role of B cell antigen receptors in mantle cell lymphoma

Abstract Abstract 3690 Mantle cell lymphoma (MCL), a less common non-Hodgkin's lymphoma (NHL), often has a poor prognosis and a median survival time of 3–5 years. Historically, MCLs were believed to originate from mature but naive B cells; this notion has now changed based on the demonstration of somatically mutated IgHV sequences in the lymphoma cells from a subset of cases. Indirect evidence suggesting that the B-cell receptor (BCR) pathway may be at the base of the observed activation in the disease exists; however, that extent that this activation results from Toll-like receptor (TLR), B-cell antigen receptor (BCR), or a combination of signaling from both has not been adequately addressed. In this study, the responsiveness of purified primary B cells isolated from peripheral blood (PB) and/or bone marrow (BM) of MCL patients in the leukemic phase of the disease to triggering via the BCR or via TLR-9 alone or in context with selected chemokines – CCL17, CCL22, or CXCL12 - was assessed using various early and late cell signaling readouts. Phosphoflow analysis revealed that within 5 minutes of stimulation both PB and BM B cells significantly increased levels of pAkt and pNFkB in response to BCR crosslinking by an anti-IgM monoclonal antibody (mAb). When PB B cells were cultured for 3 days in the presence of various stimuli to evaluate their proliferative response (uptake of 3H-thymidine), anti-BCR triggering stimulated 2 to 5.5 fold increases in DNA synthesis, whereas the TLR-9 agonist ODN2006 elicited 55 to 235 fold increases. In addition, conditions simulating T-cell help (anti-CD40 mAb + IL-4 in the presence of CD32-transfected fibroblasts) stimulated significant (40–65 fold) proliferative responses in MCL B cells. Simultaneously, a significant increase in HLA-DR (anti-BCR: 49%; ODN2006: 61%; T-cell help: 20%) and Bcl-2 expression (anti-BCR: 21%; ODN2006: 36%; T-cell help: 25%) was induced by these stimuli. Furthermore, B cells from the BM of the same cases differed in their proliferative responses based on the agonist. Thus, in response to BCR triggering, B cells from BM proliferated to a greater extent compared with PB B cells, whereas in response to TLR-9 stimulation PB B cells proliferated to a greater extent than those from BM. In independent experiments, B cells were incubated with various stimuli including those simulating T-cell help and chemokines for 3 days. Cells were harvested and extracts prepared from viable cells to determine telomerase activity using the telomere repeat amplification protocol (TRAP). Anti-BCR stimulation and anti-TLR-9 stimulation independently increased telomerase activity 1.7 and 1.9 fold, respectively, whereas in combination with CCL17 and CCL22, anti-TLR-9 stimulation further increased telomerase activity to 2.28 and 2.36 fold, respectively. In summary, these findings suggest an important role for commonly encountered microenvironmental influences interacting with TLR9 and to a lesser extent the BCR in promoting the aggressiveness of MCL. They also suggest that responses to these stimuli differ between MCL cells residing in the BM and those circulating in the blood. Finally, the data suggest that ligands for CCR4 may play an enhancing role for signals transduced by the BCR and TLR-9 in this disease. If documented in a larger number of cases, treatment regimens that target these signaling pathways might be of therapeutic value. Disclosures: No relevant conflicts of interest to declare.

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Role of CD200 in differentiating chronic lymphocytic leukaemia from mantle cell lymphoma and comparing its expression across various B cell chronic lymphoproliferative disorders

International Journal of Clinical and Diagnostic Pathology ◽

10.33545/pathol.2020.v3.i3a.256 ◽

2020 ◽

Vol 3 (3) ◽

pp. 27-31

Author(s):

Dr. Rahul Ranka ◽

Dr. Beena Brahmbhatt

Keyword(s):

Chronic Lymphocytic Leukaemia ◽

B Cell ◽

Mantle Cell Lymphoma ◽

Lymphocytic Leukaemia ◽

Cell Lymphoma ◽

Lymphoproliferative Disorders ◽

Mantle Cell

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Somatic Mutation and Isotype Switch Events Outside Igv Gene Loci Provide New Evidence for a Role of Antigenic Challenge in Mantle Cell Lymphoma Etiology

Blood ◽

10.1182/blood.v126.23.2647.2647 ◽

2015 ◽

Vol 126 (23) ◽

pp. 2647-2647

Author(s):

Sandrine Roulland ◽

Nathalie Jouve ◽

Agnes Bru ◽

Marie-Helene Delfau-Larue

Keyword(s):

B Cell ◽

Mantle Cell Lymphoma ◽

Conflicts Of Interest ◽

Cell Lymphoma ◽

High Rate ◽

Chain Gene ◽

Functional Allele ◽

Antigenic Challenge ◽

Mantle Cell

Abstract Mantle cell lymphoma (MCL) represents 5-10% of B-cell lymphomas and generally exhibits an aggressive clinical behavior. t(11;14) translocation, the genetic hallmark and early initiating event of MCL pathogenesis, lead to the constitutive CCND1 expression and consequently to cell-cycle deregulation. However, t(11;14) is also present in the blood from rare healthy individuals indicating that alone the t(11;14) is not sufficientfor malignant transformation. It has long been assumed in MCL that t(11;14)+ cells were actually carried by circulating naive and antigen-inexperienced B-cells. Yet, several reports, including long-term persistence of t(11;14)+ cells in lymphoma free-patients, biased immunoglobulin heavy variable chain gene (IgVH) repertoire and evidence of subset of cases with mutated IgVH genes led us to question this model and further investigate the role of antigenic challenge in MCL etiologic origin. As a first approach, we sought to determine the class-switch recombination (CSR) status of t(11;14)+ cells in MCL patients. CSR, as somatic hypermutation (SHM), are diversification mechanisms of the B cell receptor induced upon antigen encounter in the germinal center (GC) reaction, and absent in naive cells. Evidence for ongoing switch events in MCL has been previously reported with detection of mature switch transcripts, however in MCL cells, sIgM(D) expression remains clearly evident suggesting that effective deletional switch events occur infrequently on the functional allele. To characterize CSR in t(11;14)+ cells, we thus took advantage of their unique BCL1/IGH translocation signature assuming that BCL1/IGH fusions do not prevent CSR to occur on the downstream constant region of the IGH locus. Using 2 long-range PCR assays designed to amplify unswitched BCL1/Sµ and switched BCL1/Sγ regions, DNA from 30 MCL patients differing by their IgVH status were tested. Of the MCL cases, we confirmed that 7 of 30 (23%) were unmutated (UM, 100% germline homology) and 23 of 30 (77%) were mutated (M), considering as mutated all cases exhibiting any level of SHM (ranging from minimal: >0.3% to high rate: 7.0%). Although mutated BCRs were common in most MCL cases, we found that only 1 out of 30 MCL cases underwent CSR to IgG on the non-productive, translocated allele. Accordingly, this case carried a mutated IgVH gene with 97.5% germline identity in line with a GC/antigen-experienced signature of the tumor cells. Contrary to SHM events of the IgVH gene region, CSR deletional events appeared very infrequent in the bulk of MCL cells both on the functional and translocated allele, contrasting from findings in other GC-derived non-Hodgkin lymphomas where the same selective pressure to maintain a sIgM is accompanied by deletional switch events on the non-functional allele. To get more insights into a role of antigenic drive in MCL and AID targeting outside the VH gene loci, we next evaluated the clonal evolution of t(11;14)+ cells from 11 MCL cases (2 UM and 9 M) by analyzing SHM in the Sμ region on the translocated allele using sequencing of LR-PCR amplicons (with 2 subclones/patient). We found that 63% (7 out of 11) of BCL1/IGH clones display significant levels of SHM in the Sµ together with intra-Sµ indels (2/11) compatible with off-target AID-mediated events linked to chronic(?) antigen encounter. In addition, we found a good correlation between mutated BCR and the SHM levels in Sμ regions for a given patient. Importantly, in one instance subclones from a MCL case displayed intraclonal diversification (despite the fact that the expected rate of SHM is much lower in the Sµ region than in the IgVH region), indicative of an ongoing AID activity at least in a subset of MCL cases. In conclusion, we found that CSR events, although detectable in some MCL cases, do not appear to participate predominantly or to be selected during MCL lymphomagenesis. By contrast, analysis of SHM profiles both on the functional and the non-functional translocated allele provide evidence for an active AID activity in MCL cells inside and outside V-gene loci, highlighting the propensity of some t(11;14)+ clones to acquire a complementary oncogenic hit over time as a result of recurrent antigen challenge. Disclosures No relevant conflicts of interest to declare.

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Phospho-proteomic analysis of mantle cell lymphoma cells suggests a pro-survival role of B-cell receptor signaling

Cellular Oncology ◽

10.1007/s13402-011-0019-7 ◽

2011 ◽

Vol 34 (2) ◽

pp. 141-153 ◽

Cited By ~ 53

Author(s):

Chiara Pighi ◽

Ting-Lei Gu ◽

Irene Dalai ◽

Stefano Barbi ◽

Claudia Parolini ◽

...

Keyword(s):

B Cell ◽

Mantle Cell Lymphoma ◽

Proteomic Analysis ◽

Cell Lymphoma ◽

Cell Receptor ◽

B Cell Receptor ◽

Mantle Cell ◽

B Cell Receptor Signaling ◽

Cell Receptor Signaling

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Non-Coding RNAs in Normal B-Cell Development and in Mantle Cell Lymphoma: From Molecular Mechanism to Biomarker and Therapeutic Agent Potential

International Journal of Molecular Sciences ◽

10.3390/ijms22179490 ◽

2021 ◽

Vol 22 (17) ◽

pp. 9490

Author(s):

Olga Kersy ◽

Mali Salmon-Divon ◽

Ofer Shpilberg ◽

Oshrat Hershkovitz-Rokah

Keyword(s):

B Cell ◽

Mantle Cell Lymphoma ◽

Cell Lymphoma ◽

Cell Development ◽

B Cell Development ◽

Cellular Growth ◽

Aberrant Expression ◽

Mantle Cell ◽

Non Coding Rnas

B-lymphocytes are essential for an efficient immune response against a variety of pathogens. A large fraction of hematologic malignancies are of B-cell origin, suggesting that the development and activation of B cells must be tightly regulated. In recent years, differentially expressed non-coding RNAs have been identified in mantle cell lymphoma (MCL) tumor samples as opposed to their naive, normal B-cell compartment. These aberrantly expressed molecules, specifically microRNAs (miRNAs), circular RNAs (circRNAs) and long non-coding RNAs (lncRNAs), have a role in cellular growth and survival pathways in various biological models. Here, we provide an overview of current knowledge on the role of non-coding RNAs and their relevant targets in B-cell development, activation and malignant transformation, summarizing the current understanding of the role of aberrant expression of non-coding RNAs in MCL pathobiology with perspectives for clinical use.

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UBR5 HECT domain mutations identified in mantle cell lymphoma control maturation of B cells

Blood ◽

10.1182/blood.2019002102 ◽

2020 ◽

Vol 136 (3) ◽

pp. 299-312

Author(s):

Samantha A. Swenson ◽

Tyler J. Gilbreath ◽

Heather Vahle ◽

R. Willow Hynes-Smith ◽

Jared H. Graham ◽

...

Keyword(s):

B Cells ◽

B Cell ◽

Mantle Cell Lymphoma ◽

Malignant Transformation ◽

Cell Lymphoma ◽

Cell Maturation ◽

Hect Domain ◽

B Cell Maturation ◽

Mantle Cell

Abstract Coordination of a number of molecular mechanisms including transcription, alternative splicing, and class switch recombination are required to facilitate development, activation, and survival of B cells. Disruption of these pathways can result in malignant transformation. Recently, next-generation sequencing has identified a number of novel mutations in mantle cell lymphoma (MCL) patients including mutations in the ubiquitin E3 ligase UBR5. Approximately 18% of MCL patients were found to have mutations in UBR5, with the majority of mutations within the HECT domain of the protein that can accept and transfer ubiquitin molecules to the substrate. Determining if UBR5 controls the maturation of B cells is important to fully understand malignant transformation to MCL. To elucidate the role of UBR5 in B-cell maturation and activation, we generated a conditional mutant disrupting UBR5′s C-terminal HECT domain. Loss of the UBR5 HECT domain leads to a block in maturation of B cells in the spleen and upregulation of proteins associated with messenger RNA splicing via the spliceosome. Our studies reveal a novel role of UBR5 in B-cell maturation by stabilization of spliceosome components during B-cell development and suggests UBR5 mutations play a role in MCL transformation.

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Paired-Box 5 Positivity Related to High MIPI Score Predicts Shorter Overall Survival in Mantle Cell Lymphoma Patients

Blood ◽

10.1182/blood-2021-148289 ◽

2021 ◽

Vol 138 (Supplement 1) ◽

pp. 4481-4481

Author(s):

Yang Han ◽

Xin Zhang ◽

Yu Nie ◽

Yujie Jiang ◽

Xiaohui Sui ◽

...

Keyword(s):

Overall Survival ◽

Prognostic Factors ◽

B Cell ◽

Mantle Cell Lymphoma ◽

Poor Prognosis ◽

Clinical Characteristics ◽

Cell Lymphoma ◽

Positive Expression ◽

Mantle Cell

Abstract Introduction: Mantle cell lymphoma (MCL) is a sub-type of B-cell non-Hodgkin Lymphomas (NHL) that characterized by a heterogenous clinical course and poor prognosis. The transcription factor paired-box 5 (PAX5) is associated with B cell normal differentiation and development. Herein, we aim to explore both the prognostic factors and the role of PAX5 expression in MCL patients from single-center, which can provide theoretical guidance for clinical practice. Methods: The data of 80 MCL patients admitted to Shandong Provincial Hospital from October 2006 to April 2020 were collected to be analyzed. Kaplan-Meier method and univariate and multivariate cox analysis was used to analyze the correlation between overall survival and prognostic factors. Chi-square test, Pearson and Fisher correlation analysis were performed for statistical analysis of clinical features and experimental indicators. *p value<0.05 indicated that the difference was statistically significant. Immunohistochemistry (IHC) was used to label the protein expression. Gene expression profiles were applied to analyze the discrepancy of PAX5 mRNA expression in some lymphoma types. Results: Clinical characteristics of all MCL patients were analyzed. PAX5 expression was identified by IHC in this study: the positive expression rate of PAX5 in all MCL patients was 60% (Figure 1A). The mRNA expression level of PAX5 was obviously elevated in MCL specimens than in normal group compared with other groups (p= 0.034) (Figure 1B). Besides, CD5, CD19, CD22, CD38, CD79α, CD79β and SOX11 were shown co-expressed with PAX5 by string database analysis (Figure 1C). PAX5-related genes were found mainly enriched in lymphocyte activation, B cell proliferation and NOTCH1 signaling pathway (Figure 1D). As is shown in Figure 1E-I, MIPI score (≥6), median to high risk group, high β2-MG level (≥2.65 mg/L), ECOG score (≥2), and splenomegaly were associated with adverse survival (p= 0.006, 0.030, 0.001, 0.019 and 0.001 respectively). The positive expression of PAX5 indicated a shorter overall survival in MCL patients (p= 0.024, Figure 1G). Positive PAX5 expression was associated with international prognostic index (MIPI) score (p= 0.038), high risk stratification (p= 0.006), WBC count (p= 0.024), and increased β2-microglobulin level (p= 0.008). MCL patients with PAX5-positive expression, high level of β2-MG level (≥2.65 mg/L), splenomegaly correlated with a poorer OS (p=0.002, and 0.004 respectively, Figure 1K, L). In patients with PAX5-negative expression, splenomegaly also indicated poor prognosis (p= 0.030, Figure 1M). Furthermore, among patients with high MIPI scores, PAX5-positive MCL patients had a shorter overall survival than PAX5-negative patients (p= 0.016, Figure N, O). Multivariate analysis showed that positive PAX was an independent prognostic factor for poor survival of MCL (p= 0.035). Conclusions: The positive expression of PAX5 in immunohistochemistry may be a factor contributing to the poor prognosis of MCL patients, which is correlated with clinical characteristics and laboratory indicators to a certain extent. Our results the role of PAX5 positivity in MCL and provide clinical guidance for clinical prognostic risk assessment and treatment strategy selection. Keywords: Mantle cell lymphoma; Paired-box 5; Prognosis; Immunohistochemistry Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.

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Role of Tyrosine Kinase Inhibitors in Indolent and Other Mature B-Cell Neoplasms

Biomarker Insights ◽

10.4137/bmi.s22434 ◽

2015 ◽

Vol 10s3 ◽

pp. BMI.S22434

Author(s):

Nadine Kutsch ◽

Reinhard Marks ◽

Richard Ratei ◽

Thomas K. Held ◽

Martin Schmidt-Hieber

Keyword(s):

Tyrosine Kinase ◽

B Cell ◽

Mantle Cell Lymphoma ◽

Tyrosine Kinase Inhibitors ◽

Tyrosine Kinases ◽

Kinase Inhibitors ◽

Cell Lymphoma ◽

Chemotherapeutic Agents ◽

Mantle Cell

Targeting tyrosine kinases represents a highly specific treatment approach for different malignancies. This also includes non-Hodgkin lymphoma since it is well known that these enzymes are frequently involved in the lymphomagenesis. Hereby, tyrosine kinases might either be dysregulated intrinsically or be activated within signal transduction pathways leading to tumor survival and growth. Among others, Bruton's tyrosine kinase (Btk) is of particular interest as a potential therapeutic target. Btk is stimulated by B-cell receptor signaling and activates different transcription factors such as nuclear factor KB. The Btk inhibitor ibrutinib has been approved for the treatment of chronic lymphocytic leukemia and mantle-cell lymphoma recently. Numerous clinical trials evaluating this agent in different combinations (eg, with rituximab or classical chemotherapeutic agents) as a treatment option for aggressive and indolent lymphoma are under way. Here, we summarize the role of tyrosine kinase inhibitors in the treatment of indolent and other non-Hodgkin lymphomas (eg, mantle-cell lymphoma).

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