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

Blood ◽  
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.

scholarly journals E3 Ligase UBR5 HECT domain mutations in lymphoma control maturation of B cells via alternative splicing

2019 ◽  
Author(s):  
Samantha A. Swenson ◽  
Tyler J. Gilbreath ◽  
Heather Vahle ◽  
R. Willow Hynes-Smith ◽  
Jared H. Graham ◽  
...  
Keyword(s):  
Alternative Splicing ◽  
B Cells ◽  
B Cell ◽  
Cell Lymphoma ◽  
B Cell Development ◽  
Cell Maturation ◽  
Hect Domain ◽  
B Cell Maturation ◽  
Mantle Cell

ABSTRACTCoordination 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 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 which 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 up-regulation of proteins associated with mRNA splicing via the spliceosome. Our studies reveal a novel role of UBR5 in B cell maturation by regulating alternative splicing of key transcripts during B cell development and suggests UBR5 mutations may promote mantle cell lymphoma initiation.KEY POINTSUtilizing a novel mouse model mimicking MCL patient mutations, the loss of UBR5’s HECT domain causes alterations in B cell development.UBR5 mutations lead to stabilization of UBR5 and aberrant splicing.

Non-MTC IGH-CCND1 Breakpoints in Mantle Cell Lymphoma Are Associated with CpG Sites and AID Hotspots

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 398-398
Author(s):  
Harvey A Greisman ◽  
Zhengfei Lu ◽  
Albert G Tsai ◽  
Timothy C. Greiner ◽  
Hye Son Yi ◽  
...  
Keyword(s):  
B Cell ◽  
Mantle Cell Lymphoma ◽  
Light Chain ◽  
Cell Lymphoma ◽  
Cell Maturation ◽  
Light Chain Restriction ◽  
Ccnd1 Gene ◽  
Cpg Sites ◽  
B Cell Maturation ◽  
Mantle Cell

Abstract Abstract 398 Most t(11;14)(q13;q32) breakpoints in mantle cell lymphoma (MCL) are scattered across a large genomic region centromeric to the CCND1 gene on chromosome 11q13. However, few t(11;14) breakpoints outside the major translocation cluster (MTC) have been sequenced. We report our analysis of 56 IGH-CCND1 fusion sequences from 32 non-MTC cases of MCL. Our analysis reveals remarkable breakpoint diversity at both CCND1 and IGH loci. The CCND1 breakpoints are located from 2 kb to 331 kb from the CCND1 gene, including 12 breakpoints (38%) in the 220kb region centromeric to the MTC, which is itself located 110 kb centromeric to the CCND1 gene. Twenty-one cases had a JH coding end breakpoint on the der(14) chromosome and a DH coding end breakpoint on the der(11). Two cases had der(14) and der(11) breakpoints derived from the coding and signal ends of the same JH or DH gene segment; one case had a JH/DH breakpoint on the der(14) and a VH breakpoint on the der(11); and one case had a breakpoint in the JH region located >100 bases from the nearest RSS motif, suggesting a RAG-independent break at IGH. No der(11) breakpoint could be amplified in eight cases. In sixteen cases (50%), one or both CCND1 breakpoints were within 4 bases of a CpG dinucleotide, a feature characteristic of translocation breakpoints in many human B cell lymphomas. Three CpG-associated “microclusters” were identified, i.e. breakpoints in two different tumors located at or near the same CpG site. Breakpoints in the sixteen (50%) “non-CpG” cases showed a significant association with AID hotspot motifs at the CCND1 locus. In addition, the non-CpG breakpoints were more likely to: 1) be located telomeric to the MTC, 2) involve 3' JH and 5' DH gene segments, and 3) be associated with immunoglobulin lambda light chain restriction; features that suggest occurrence at a late stage of pre-B cell maturation. In contrast, the CpG-associated breakpoints were: 1) more likely to be centromeric to the MTC, 2) not biased in their JH or DH segment usage, and 3) associated with kappa light chain restriction; features suggesting occurrence in an earlier pre-B cell or pro-B cell. Our results implicate AID in chromosomal breakage at both CpG and non-CpG sites within the CCND1 locus and suggest that AID and RAG collude to generate the chromosomal breaks underlying the t(11;14). Our findings also suggest that IGH-CCND1 rearrangements can occur at different stages of pre-B cell maturation. This study provides novel insights into the mechanism and developmental timing of the t(11;14) in human MCL, features that are likely to be relevant to a broad range of human lymphomas. Disclosures: Greisman: Signature Genomics, LLC: Patents & Royalties. Yi:Signature Genomics, LLC: Patents & Royalties.

scholarly journals The B-cell tumor–associated antigen ROR1 can be targeted with T cells modified to express a ROR1-specific chimeric antigen receptor

Blood ◽  
2010 ◽  
Vol 116 (22) ◽  
pp. 4532-4541 ◽  
Author(s):  
Michael Hudecek ◽  
Thomas M. Schmitt ◽  
Sivasubramanian Baskar ◽  
Maria Teresa Lupo-Stanghellini ◽  
Tetsuya Nishida ◽  
...  
Keyword(s):  
T Cells ◽  
B Cells ◽  
B Cell ◽  
Mantle Cell Lymphoma ◽  
Chimeric Antigen Receptor ◽  
Cell Lymphoma ◽  
Embryonic Stem ◽  
Antigen Receptor ◽  
Orphan Receptor ◽  
Mantle Cell

Monoclonal antibodies and T cells modified to express chimeric antigen receptors specific for B-cell lineage surface molecules such as CD20 exert antitumor activity in B-cell malignancies, but deplete normal B cells. The receptor tyrosine kinase-like orphan receptor 1 (ROR1) was identified as a highly expressed gene in B-cell chronic lymphocytic leukemia (B-CLL), but not normal B cells, suggesting it may serve as a tumor-specific target for therapy. We analyzed ROR1-expression in normal nonhematopoietic and hematopoietic cells including B-cell precursors, and in hematopoietic malignancies. ROR1 has characteristics of an oncofetal gene and is expressed in undifferentiated embryonic stem cells, B-CLL and mantle cell lymphoma, but not in major adult tissues apart from low levels in adipose tissue and at an early stage of B-cell development. We constructed a ROR1-specific chimeric antigen receptor that when expressed in T cells from healthy donors or CLL patients conferred specific recognition of primary B-CLL and mantle cell lymphoma, including rare drug effluxing chemotherapy resistant tumor cells that have been implicated in maintaining the malignancy, but not mature normal B cells. T-cell therapies targeting ROR1 may be effective in B-CLL and other ROR1-positive tumors. However, the expression of ROR1 on some normal tissues suggests the potential for toxi-city to subsets of normal cells.

TLR-9 and B-Cell Antigen Receptor Triggering of Primary B Cells From Mantle Cell Lymphoma Induce Cell Proliferation and Telomerase Activity,

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 3690-3690
Author(s):  
Sonal Temburni ◽  
Ryon M. Andersen ◽  
Steven L. Allen ◽  
Jaqueline C. Barrientos ◽  
Jonathan E. Kolitz ◽  
...  
Keyword(s):  
T Cell ◽  
B Cells ◽  
B Cell ◽  
Mantle Cell Lymphoma ◽  
Cell Lymphoma ◽  
Telomerase Activity ◽  
B Cell Antigen Receptor ◽  
Cell Antigen ◽  
Mantle Cell ◽  
T Cell Help

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.

scholarly journals Cyclin D1 Expression in Mantle Cell Lymphoma Is Accompanied by Downregulation of Cyclin D3 and Is Not Related to the Proliferative Activity

Blood ◽  
1997 ◽  
Vol 90 (8) ◽  
pp. 3154-3159 ◽  
Author(s):  
M. Michaela Ott ◽  
Jirina Bartkova ◽  
Jiri Bartek ◽  
Alexander Dürr ◽  
Lars Fischer ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Cyclin D1 ◽  
Mantle Cell Lymphoma ◽  
Cell Lines ◽  
Cell Lymphoma ◽  
Chromosomal Translocation ◽  
Germinal Centers ◽  
Cyclin D3 ◽  
Mantle Cell

Abstract The cell cycle regulatory protein cyclin D1 is essential for G1-S phase transition in several epithelial and mesenchymal tissues but is apparently not essential in normal mature B cells. An overexpression of cyclin D1 is induced by the chromosomal translocation t(11; 14)(q13; q32), which characterizes non-Hodgkin's lymphomas (NHLs) of mantle cell type. We studied 26 cases of mantle cell lymphoma (MCL) for the expression of cyclins D1 and D3. A total of 23 lymphomas showed a nuclear staining for cyclin D1, whereas reactive B cells of residual germinal centers were constantly negative. When compared with cyclin D3, an inverse staining pattern emerged. Whereas the B cells of residual germinal centers reacted strongly positive for cyclin D3, there was low or missing expression of cyclin D3 in MCL cells. In other B-cell lymphomas (n = 55), including chronic lymphocytic leukemia, low-grade lymphomas of mucosa-associated lymphatic tissue, follicular lymphomas, and diffuse large B-cell lymphomas, no cyclin D1 expression could be detected and 89% of these cases displayed cyclin D3 positivity. Lymphoma cell lines harboring the t(11; 14) showed cyclin D1 protein but no or very low levels of cyclin D3; three other B-cell lines, a T-cell line, and peripheral blood lymphocytes strongly expressed cyclin D3 and reacted negatively for cyclin D1. We conclude that the chromosomal translocation t(11; 14) leads to an abnormal protein expression of cyclin D1 in the tumor cells of MCL and induces a consecutive downregulation of cyclin D3. In contrast to other B-NHLs, cyclin D1 and D3 expression in MCL is not related to the growth fraction.

Constitutive Chemokine Receptor Expression in B-Cell Non-Hodgkin’s Lymphoma.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 3590-3590
Author(s):  
Michelle S. Bryson ◽  
Ruth F. Jarrett ◽  
Lesley Sheild ◽  
Gerard J. Graham
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
B Cell ◽  
Mantle Cell Lymphoma ◽  
Hodgkin’S Lymphoma ◽  
Memory T Cells ◽  
Cell Lymphoma ◽  
Hodgkin's Lymphoma ◽  
Mantle Cell

Abstract Chemokines are small peptides (∼8-14KDa) that play an essential role in both the innate and adaptive immune system. Chemokines are primarily involved in leukocyte trafficking, but are also involved in a number of cellular mechanisms. They elicit their effect through G-protein coupled receptors, the chemokine receptors (CKR). Functionally chemokines and their receptors are classified as inflammatory or constitutive. Constitutive CKRs and their ligands have a role in numerous diseases including malignancy, chronic inflammation and HIV infection. This study aimed to examine constitutive CKR expression in sub-types of B-cell NHL, of which there are limited studies so far. Lymph node preparations from patients with NHL were examined by flow cytometry using antibodies to CD20, CCR4, CCR6, CCR7, CCR9, CCR10, CXCR4 and CXCR5. The percentage of CD20 positive cells expressing the CKR under investigation was then calculated. The following cases were examined; follicular lymphoma (FL), n=11, Diffuse large B-cell lymphoma (DLBCL), n=11, mantle cell lymphoma (MCL) n=17, Burkitt’s lymphoma (BL), n=9 and MALT lymphoma, n=10. A number of differences between NHL sub-types were detected. FL cases generally had a lower expression of all the CKRs. CXCR5 and CXCR4 expression was high in all sub-types (>84% of B-cells) with no significant differences found, this would be expected as these CKRs are widely expressed in all B-cells. CCR10 expression was low or absent, with no significant differences detected. CCR6 and CCR9 show highest expression in MALT lymphomas, consistent with previous studies, but in comparison with other sub-types the differences was not significant. The most significant results were found with CCR7 and CCR4. CCR7 is expressed on naive T-cells, memory T-cells, B-cells and dendritic cells and is involved in the homing of lymphocytes to lymph nodes. CCR7 is currently the second most commonly reported CKR to be upregulated in malignancy, after CXCR4 and is related. We found very high levels of CCR7 in Mantle cell lymphoma (>90% of B-cells) as compared to other sub-types (p=0.005). CCR4 is expressed on Th2 and Treg lymphocytes, memory T cells and in a small subset of mature B-cells. CCR4 expression in T-cells has been correlated with an adverse prognosis in T-cell NHL and Hodgkin’s lymphoma, yet no systematic studies looking at CCR4 expression in B-cell neoplasms has been reported. These results showed a significant increase in CCR4 expression (>50% of B-cells) in DLBCL, MCL, MALT and BL as compared to FL (p<0.0001). We showed that there are differences in constitutive CKR expression in the different B-cell NHL types, with CCR4 expression being the most interesting finding. How CCR4 expression relates to prognosis in these lymphomas is as yet unknown but is under investigation. Targeting of the chemokine system using anti-CCR4 is already being used in clinical trials for T-cell neoplasms, and may be of potential benefit in selected B-cell neoplasms. Furthermore, the development of anti-CCR7 strategies may prove to be of benefit in the traditionally poor prognosis MCL patients.

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 ◽  
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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