scholarly journals Aberrant Expression of the SOX11 Oncogene in Mantle Cell Lymphoma Is Associated with Activation and De Novo 3D Looping of a Distant Enhancer Element

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 459-459
Author(s):  
Roser Vilarrasa-Blasi ◽  
Ana C. Queirós ◽  
Renée Beekman ◽  
Nuria Russiñol ◽  
Giancarlo Castellano ◽  
...  
Keyword(s):  
B Cells ◽  
Cell Lines ◽  
De Novo ◽  
Memory B Cells ◽  
Primary Case ◽  
Enhancer Activity ◽  
Histone Marks ◽  
Mantle Cell ◽  
3D Fish ◽  
Putative Enhancer

Abstract Introduction SOX11 is a transcription factor (TF) aberrantly expressed in the majority of mantle cell lymphomas (MCLs), which is generally associated with aggressive clinical behaviour. No mutations, genetic aberrations or direct correlations with differential DNA methylation at the promoter related to its expression have been found in MCL. Deeper insights into its regulation can be found by considering the three-dimensional (3D) chromatin structure. It is becoming clear that the genome can be partitioned into 3D building blocks, topologically associated domains (TADs) and that enhancer regions likely regulate genes within their TADs by 3D contacts, but do not affect genes outside their own TADs. By mapping the 3D chromatin structure, we previously identified a distant putative SOX11 enhancer showing enhancer activity and 3D contacts with the SOX11 gene in the SOX11-positive MCL cell line Z-138, but not in the SOX11-negative MCL cell line JVM-2. Aims We aimed to deepen our understanding of the differential 3D contacts and enhancer activity previously observed at the putative SOX11 enhancer in SOX11-positive versus SOX11-negative MCL cell lines by addressing the following questions: (i) Do TAD boundaries around the SOX11 locus change between SOX11-positive and -negative MCLs? (ii) How do the 3D contacts and chromatin states at this region behave in primary MCL cases and normal B cells? (iii) Is the putative SOX11 enhancer involved in SOX11 expression in other tissues? Methods We have extended our experimental analyses of the putative SOX11 enhancer by performing (i) HiC-sequencing and 3D fluorescence in situ hybridization (3D FISH) in MCL cell lines Z-138 and JVM-2, (ii) 4C-sequencing, chromatin inmmunoprecipiation followed by deep sequencing (ChIP-seq) of 6 histone marks, an Assay for Transposase-Accessible Chromatin with deep sequencing (ATAC-seq) and chromatin state modeling by chromHMM (using the 6 histone marks) in primary MCL cases and normal naive and memory B-cells. Furthermore, we have explored the activity of this region in other SOX11 expressing cell lines studied within the ENCODE Consortium. Results HiC-sequencing in the cell lines Z-138 (SOX11-positive) and JVM-2 (SOX11-negative) showed that the SOX11 locus and its putative enhancer are located within the same TAD in both samples. Hence, shifts in TAD boundaries do not seem to underlie the differential 3D chromatin interactions between the SOX11 locus and its putative enhancer in these two cell lines. By ChIP-seq and chromatin state modeling we observed that the promoter of SOX11 is poised, i.e., carrying histone marks H3K4me3 and H3K27me3, in normal naive and memory B-cells and the SOX11-negative MCL primary case. Furthermore, we observed weak enhancer activity at the putative SOX11 enhancer in normal naive and memory B-cells and the SOX11-negative MCL primary case, but strong enhancer activity, marked by the presence of H3K27ac, only in SOX11-positive samples. In addition, by ATAC-seq we identified two specific chromatin accessible regions that potentially represent the transcription factor binding sites responsible for activation of this enhancer region in SOX11-positive MCLs. By 4C-sequencing we observed that the SOX11 locus and its putative enhancer show high 3D contacts in two other SOX11-positive MCL cell lines (GRANTA-519 and JEKO-1) and in a SOX11-positive primary MCL case, but not in a SOX11-negative primary MCL case. Furthermore, the differential 3D contacts at these regions in Z-138 and JVM-2 were confirmed by 3D FISH, which is currently being performed in primary MCL cases. Interestingly, no 3D contacts were observed in normal naive and memory B cells, indicating that although the SOX11 promoter is poised within these normal B-cell subpopulations, primed looping at these regions does not exist and seems not to explain the 3D contacts we observed in SOX11-positive MCL cell lines and primary cases. When investigating chromatin states in cell lines studied by ENCODE with an active SOX11 promoter (H1-hESC, HSMM and NHLF) none of them show activity in the identified region, suggesting that the putative SOX11 enhancer is de novo activated only in the context of MCL lymphomagenesis. Conclusions We provide new evidence that the activation of a distant SOX11 putative enhancer and its 3D contacts to the SOX11 gene, is a de novo event in SOX11-positive MCL cell lines and primary cases that is likely specific for this malignancy. Disclosures No relevant conflicts of interest to declare.

The Suppressor of Cytokine Signaling-3 Gene Is Overexpressed in Human De Novo Follicular Lymphomas and Promotes IL-3-Independent Proliferation of the BaF3 Pro-B Cell Line.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 1107-1107
Author(s):  
Jacqueline C. Barrientos ◽  
Sofya Rodov ◽  
Arthur W. Zieske ◽  
K. Gary J. Vanasse
Keyword(s):  
Cell Proliferation ◽  
B Cells ◽  
B Cell ◽  
Cell Line ◽  
Cell Lines ◽  
De Novo ◽  
Myeloid Cells ◽  
Negative Regulator ◽  
Cytokine Signaling ◽  
Socs3 Protein

Abstract The recent generation of mice lacking functional SOCS3 in hepatocytes, macrophages, and neutrophils reveals SOCS3 to be an essential regulator of IL-6 signaling via mediation of gp130-related cellular complexes, as well as a negative regulator of G-CSF signaling in myeloid cells. Although SOCS3 would appear to be a critical physiologic regulator of inflammatory responses, its possible role in hematologic malignancies and the underlying mechanisms which regulate its expression in B cells remain to be clearly defined. We previously showed that CD19+ B cells isolated from Eμ-Bcl-2 transgenic mice express high levels of SOCS3 in addition to overexpression of Bcl-2. Moreover, hematopoietic cell lines transduced to stably overexpress Bcl-2 exhibited marked induction of SOCS3 compared to controls, suggesting Bcl-2-associated pathways may play a role in the induction of SOCS3. In the current study, we describe SOCS3 overexpression limited to neoplastic follicular lymphoma (FL) cells in Bcl-2-associated human de novo FL and show that overexpression of SOCS3 is capable of stimulating cytokine-independent cellular proliferation of the BaF3 pro-B cell line. We measured SOCS3 protein levels by immunohistochemistry in paraffin-embedded biopsies from twelve patients diagnosed with de novo, untreated histologic grade I or II FL which harbored t(14;18) and Bcl-2 overexpression. In 9/12 de novo FL cases examined, immunostaining with two distinct antibodies to SOCS3 revealed marked overexpression of SOCS3 protein that, within the follicular center cell region, was limited to neoplastic FL cells and co-localized with Bcl-2 primarily in the nucleus of positive cells. In contrast, SOCS3 protein was not detected by immunostaining in germinal center follicular B cells from benign hyperplastic tonsil tissue. To further evaluate the role of SOCS3 in B cell biology, the IL-3-dependent BaF3 pro-B cell line was stably transduced with either a retroviral expression construct containing a 675bp human SOCS3 cDNA (BaF3SOCS3) or with vector only control (BaF3Δ). Whereas no SOCS3 protein was detected in control cells, high level expression of SOCS3 in transduced BaF3SOCS3 cells was confirmed by Western analysis using SOCS3 anti-sera. Furthermore, Bcl-2 protein was not detected in either BaF3SOCS3 or control cell lines. 2 x 105 BaF3SOCS3, BaF3Δ, and non-transduced BaF3 cell lines were initially grown in the presence 10% fetal bovine serum (FBS) and 5% WEHI 3B cell-conditioned medium as a source of IL-3. IL-3 was then removed by washing with DMEM/10% FBS. Cell viability was then measured by recording absorbance at 490nm using incorporation of the MTS tetrazolium compound. Interestingly, BaF3SOCS3 cells overexpressing SOCS3 did not undergo apoptosis but were able to proliferate in the absence of IL-3, with percent viable cells approaching 400% at > 96 hours, which represented the final time-point measured. In contrast, BaF3Δ and non-transduced BaF3 cells underwent apoptotic cell death between 8 and 36 hours in response to IL-3 withdrawal. Thus, SOCS3 overexpression confers IL-3-independent cell proliferation to the BaF3 cell line. These data indicate that unlike its negative regulatory effect on G-CSF signaling in myeloid cells, overexpression of SOCS3 in B cells may promote B cell proliferation rather than growth suppression and may play an important role in the pathogenesis of de novo FL in humans.

scholarly journals SARS-CoV-2 sculpts the immune system to induce sustained virus-specific naïve-like and memory B cell responses

2021 ◽  
Author(s):  
Leire de Campos-Mata ◽  
Sonia Tejedor Vaquero ◽  
Roser Tachó-Piñot ◽  
Janet Piñero ◽  
Emilie K. Grasset ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
De Novo ◽  
Acute Infection ◽  
Memory B Cells ◽  
Cell Responses ◽  
Specific Memory ◽  
Virus Specific Antibody ◽  
B Cell Responses ◽  
B Cell Precursors

SARS-CoV-2 infection induces virus-reactive memory B cells expressing unmutated antibodies, which hints at their emergence from naïve B cells. Yet, the dynamics of virus-specific naïve B cells and their impact on immunity and immunopathology remain unclear. Here, we longitudinally studied moderate to severe COVID-19 patients to dissect SARS-CoV-2-specific B cell responses overtime. We found a broad virus-specific antibody response during acute infection, which evolved into an IgG1-dominated response during convalescence. Acute infection was associated with increased mature B cell progenitors in the circulation and the unexpected expansion of virus-targeting naïve-like B cells that further augmented during convalescence together with virus-specific memory B cells. In addition to a transitory increase in tissue-homing CXCR3+ plasmablasts and extrafollicular memory B cells, most COVID-19 patients showed persistent activation of CD4+ and CD8+ T cells along with transient or long-lasting changes of key innate immune cells. Remarkably, virus-specific antibodies and the frequency of naïve B cells were among the major variables defining distinct immune signatures associated with disease severity and inflammation. Aside from providing new insights into the complexity of the immune response to SARS-CoV-2, our findings indicate that the de novo recruitment of mature B cell precursors into the periphery may be central to the induction of antiviral immunity.

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.

Selective Inhibition of I kappaB Kinase Sensitizes Mantle Cell Lymphoma B Cells to TRAIL by Decreasing c-FLIP Level.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 258-258
Author(s):  
Gaël Roué ◽  
Patricia Pérez-Galán ◽  
Mónica López-Guerra ◽  
Neus Villamor ◽  
Elias Campo ◽  
...  
Keyword(s):  
B Cells ◽  
Mantle Cell Lymphoma ◽  
Cell Lines ◽  
Cell Lymphoma ◽  
Receptor Expression ◽  
Cytotoxic Effects ◽  
Ikappab Kinase ◽  
Mantle Cell ◽  
Nf Kappab ◽  
Factor C

Abstract Mantle cell lymphoma (MCL) is an aggressive B lymphoid neoplasm with a mature B-cell phenotype and genetically characterized by the t(11;14)(q13;q32) leading to cyclin D1 overexpression with the consequent deregulation of cell cycle at the G1-S checkpoint. MCL cells also present a constitutive activation of the NF-kappaB pathway which leads to the overexpression of several anti-apoptotic regulators. We have analyzed sensitivity to the extrinsic apoptotic signal triggered by tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) on six human MCL cell lines and primary cells from 10 MCL patients, which differ in their p53-dependent pathway status, growth characteristics and sensitivity to cytotoxic drugs. TRAIL has been shown to exert in vivo a selective anti-tumor activity with minimal toxicity on normal cells. We observed that TRAIL was able to trigger apoptosis in a majority of MCL cell lines and primary MCL tumor cells, while sparing normal peripheral B cells. TRAIL-induced cell death was characterized by a time- and dose-dependent loss of membrane potential, Bax and Bak activation, caspase activation and phophatidylserine exposure. MCL sensitivity to TRAIL was irrespective of TRAIL-R1 and TRAIL-R2 receptor levels, Bcl-2 family members or caspase regulators expression, but was closely linked to the activity of the NF-kappaB p50 factor and to the expression of c-FLIP, a NF-kappaB-regulated factor. C-FLIP accumulated into the TRAIL-dependent complex in resistant cells and its transient knockdown overcame MCL resistance to TRAIL. In parallel, NF-kappaB inhibitors differentially modulated TRAIL cytotoxicity. Indeed, sub-toxic doses of bortezomib increased TRAIL cytotoxic effects by up-regulating TRAIL-R2 receptor expression, but also led to the intracellular accumulation of c-FLIP, impeding full synergistic interaction in cells with highest c-FLIP basal level. In contrast, the IkappaB kinase (IKK) inhibitor BMS-354451 allowed to consistent reduction of NF-kappaB activity, decreased total and DISC-associated c-FLIP levels, and sensitized all MCL cells to TRAIL cytotoxic effects. These results indicate that pharmacological enhancement of MCL cells sensitivity to TRAIL does not depend on TRAIL receptors level but is rather regulated by NF-kappaB-regulated c-FLIP expression. Considering that both TRAIL and BMS-345541 have already demonstrated selective cytotoxicity against malignant cells, combining TRAIL, with pharmacological inhibitors of IkappaB kinase signaling may represent an attractive model for the design of a new and rational combination therapy for MCL.

Direct Growth Inhibition of Both Mouse and Human B Cell Lymphomas by CpG Oligodeoxynucleotides

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 2854-2854
Author(s):  
Reiko E Yamada ◽  
David J Betting ◽  
Michael Ahdoot ◽  
Kristopher K Steward ◽  
John M Timmerman
Keyword(s):  
B Cells ◽  
B Cell ◽  
Cell Lines ◽  
B Cell Lymphoma ◽  
B Cell Lymphomas ◽  
Cpg Oligodeoxynucleotides ◽  
Mantle Cell ◽  
Class B ◽  
Human B Cell

Abstract Abstract 2854 Immunostimulatory CpG oligodeoxynucleotides (ODN) are potent activators of T cell immunity and antibody-dependent cellular cytotoxicity (ADCC), and under study as immunotherapeutic agents for a variety of cancers, including B cell lymphomas. Recently, anti-CD20 antibody-CpG conjugates have been shown to eradicate rituximab-resistant B cell lymphoma in a syngeneic murine lymphoma model (D. Betting et al, ASH 2009). CpG is known to strongly stimulate the proliferation of normal B cells. Paradoxically, CpG has been reported to markedly inhibit the in vitro growth of the murine B cell lymphoma A20 (J. Li et al, J. Immunol. 2007), thereby prompting us to investigate the direct effects of CpGs on the growth of human B cell lymphomas. We first demonstrated that CpGs, especially those of the B class, potently inhibited proliferation of the A20 mouse B cell line in vitro by up to 81.5% (class A 58.7% and class C 52.7%). Moreover, in non-tumor bearing mice intratumoral injections of CpG activated normal B cells, while mice bearing subcutaneous A20 tumors showed suppressed tumor growth after CpG injections. Similarly, in humans, CpGs strongly stimulated the proliferation of normal peripheral blood B cells (stimulation index for class B 27.5 at 5 μg/ml). A panel of 12 human lymphoma cell lines (DLBCL, Burkitt's, mantle cell) were cultured in the presence or absence of varying concentrations of CpGs of A, B, or C classes (50, 10, or 2 μg/ml) or control ODN. Proliferation was measured by [3H]-thymidine incorporation in quadruplicate 72 hour cultures, and apoptosis measured by Annexin-V and PI flow cytometry. In contrast to the stimulation observed with normal human B cells, the proliferation of all 12 lymphoma lines were inhibited by CpGs. The strongest inhibitory effects were seen with CpG 7909, a class B CpG under clinical development for cancer therapy (Pfizer, PF-3512676). Raji cells were inhibited by 77.9%, 40.7%, and 8.8% at CpG concentrations of 50, 10, and 2 μg/ml, respectively (p≤0.01 for all comparisons vs. media alone). Among the 12 tested cell lines, the percentage growth inhibition using 50 μg/ml CpG 7909 was 61.2–80.4% for germinal center-type DLBCL (SUDHL-4, SUDHL-6, OCI-Ly19), 50–59.5% for activated B cell-type DLBCL (SUDHL-2, OCI-Ly3, OCI-Ly10), 56.4–79.3% for Burkitt's lymphomas (Raji, Ramos, Daudi, BJAB), and 69.6–69.9% for mantle cell lymphomas (Jeko-1, Granta-519). Interestingly, although all of the human cell lines expressed TLR9 by semi-quantitative RT-PCR, inhibition in the proliferation levels did not correlate with TLR9 expression levels. CpG 7909 also induced significant levels of apoptosis in Raji and Jeko-1 cells, 10.1% and 27.6% respectively at 50 μg/ml. In conclusion, we have demonstrated that CpGs have divergent effects on normal versus malignant B cells in both mouse and human systems. Delivery of CpG to mouse lymphoma cells inhibited their growth in vivo, while normal mouse B cells were activated. Furthermore, CpGs directly inhibit the proliferation of a large panel of human B cell lymphomas representing the majority of aggressive histologies. These results provide a novel mechanism of action for CpGs as therapeutic agents for B cell lymphomas. Disclosures: No relevant conflicts of interest to declare.

Novel CRM-1 Inhibitors for Therapy In Mantle Cell Lymphoma

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 2734-2734
Author(s):  
Kejie Zhang ◽  
Lan V Pham ◽  
Liang Zhang ◽  
Archito T. Tamayo ◽  
Zhishuo Ou ◽  
...  
Keyword(s):  
B Cells ◽  
Western Blot ◽  
Mantle Cell Lymphoma ◽  
Cell Lines ◽  
Cell Lymphoma ◽  
Parp Cleavage ◽  
Mantle Cell ◽  
Dose Dependent

Abstract Abstract 2734 Chromosomal Region Maintenance 1 (CRM1) overexpression has been associated with cancer progression and mortality in several human cancers, suggesting that activation of nuclear export may play a role in human neoplasia and may serve as a novel target for the treatment of cancers. This overexpression of CRM1 may be related to the export of most tumor suppressor and growth regulatory proteins out of the nucleus, thereby functionally inactivating them. Mantle cell lymphoma (MCL) is an aggressive histotype of B-cell non-Hodgkin lymphoma that is not yet curable. The objective of our study was to investigate the status of CRM1 in MCL, both in MCL cell lines and primary MCL cells, in comparison to normal B cells, and to evaluate the therapeutic efficiency of CRM1 inhibition in MCL in vitro and in vivo, and to elucidate the mechanism of CRM1 inhibitor-mediated MCL cell apoptosis. We used 8 established MCL cell lines and primary cells from 4 patients with relapsed/refractory MCL. KPT185 and KPT276 are novel, highly selective, drug-like small molecular CRM1 inhibitors. Western Blot analysis showed that CRM1 was expressed in both the cytoplasm and nuclei of 8 MCL cell lines. CRM1 was mainly detected in nuclei of normal resting B cells; In contrast, CRM1 was primarily detected in the cytoplasm of freshly isolated primary MCL cells from patients with relapsed/refractory MCL. In 3H-thymidine incorporation assays, inhibition of CRM1 by KPT185 resulted in a significant dose-dependent growth inhibition of 8 MCL cells, with IC50 values range between 10 nM to 120 nM. The blastoid-variant MCL cell lines (Z-138 and Rec-1) were significantly more sensitive to KPT185 than the non-blastoid variant MCL cell lines. Flow cytometry analysis with fluorescence-labeled Annexin V and propidium iodide showed that KPT185 induced MCL cells apoptosis in both time- and dose-dependent manners, but had no effect on cell cycle arrest. MCL cells treated with KPT185 for 12 hours showed caspase 3 activation and PARP cleavage. As shown in Western blot and confocal microscopy, blocking CRM1 activity by KPT185 in MCL cells up-regulated the protein expression of p53, a known CRM1-mediated export protein, and also induced CRM1 translocation to the nucleus and decreased CRM1 expression. In severe combined immunodeficient (SCID) mice bearing palpable Z-138 tumors, treatment with KPT-276 (similar structure to KPT-185 but improved animal pharmacokinetics), 50mg/kg or 150 mg/kg PO QDx5 each week, or cyclophosphamide 100 mg/kg on days 1–3, was initiated. Tumor growth was significantly inhibited (>75%) in all of treatment groups compared with vehicle control. Neutropenia and other cytotoxic-agent specific effects have not been observed in treated animals. In conclusion, CRM1 inhibitors inhibited growth of MCL cells in vitro and in vivo, and induced apoptosis of MCL cells via inhibition of CRM1 expression and blockage of its translocation with functional nuclear proteins. Our data suggest that novel CRM1 inhibitors provide a potential therapy for patients with relapsed/refractory MCL. Disclosures: No relevant conflicts of interest to declare.

CD31/PECAM-1 Is Overexpressed On Mantle-Cell Lymphoma (MCL) Primary Cells and Positively Regulates Engraftment and Growth of MCL Cell Lines in Immunodeficient Mice.

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 2681-2681
Author(s):  
Jan Molinsky ◽  
Magdalena Klanova ◽  
Bokang Maswabi ◽  
Josef Karban ◽  
Martin Spacek ◽  
...  
Keyword(s):  
Bone Marrow ◽  
B Cells ◽  
Cell Lines ◽  
Peripheral Blood ◽  
Cell Lymphoma ◽  
Immunodeficient Mice ◽  
Mantle Cell ◽  
Original Cell ◽  
Cd31 Expression

Abstract Abstract 2681 Mantle-cell lymphoma (MCL) is a lymphoma subtype with poor prognosis. Recently, new drugs targeting at least partially the angiogenesis cascade have been successfully tested in the therapy of relapsed MCL patients, including temsirolimus, enzastaurin and lenalidomide. To reveal molecular mechanisms that regulate MCL-induced angiogenesis (and that might represent potential new druggable targets), we established and analyzed two mouse models of human MCL. Immunodeficient mice were subcutaneously (s.c.) xenografted with MCL cell lines JEKO-1 and HBL-2, and when tumor diameters reached 3cm in any size, the mice were sacrificed, and the excized tumors subjected to immunohistochemical (IHC) analysis. Alternatively, ex vivo obtained MCL cells were magnetically sorted using CD45 microbeads, and subjected to gene expression and flow cytometry analyses compared to the in vitro growing controls. IHC analysis proved that the tumors were neovascularized. Gene expression profiling by TaqMan Human Angiogenesis Array revealed that the most upregulated gene in both JEKO-1 and HBL-2 in vivo vs. in vitro growing cells was platelet/endothelial cell adhesion molecule CD31/PECAM-1 (fold change 148.9 ± 19.4, and 127.6 ± 10.5, respectively). Recently, Boyd et al. reported upregulation of CD31 in three of five primary MCL samples compared to normal B cells by Western blotting. By flow cytometry we assessed surface expression of CD31 on primary cells obtained from peripheral blood and bone marrow of 25 MCL patients before therapy. The percentage of CD31 positive cells was significantly higher in the subset of CD19+CD5+ peripheral blood MCL cells compared to CD19+CD5+ healthy donor B-cells (78.6± 4.4 vs. 14.7±2.6, p< 0.001), as well as in the subset of CD19+CD5+ bone marrow MCL cells compared to CD19+CD5+ B-cells obtained from the bone marrow of patients with various lymphoma subtypes with no detectable bone marrow involvement (81.9±3.9 vs. 20.5±4.8, p< 0.0001). In addition to surface CD31 we asked if patients with MCL have increased levels of soluble form of CD31 (sCD31) compared to healthy volunteers. We measured concentrations of sCD31 in plasma samples obtained from 17 MCL patients before therapy by ELISA. Despite the fact that MCL patients demonstrated higher variability in sCD31 concentrations (range 10.7–135.6 ng/ml) compared to healthy volunteers (range 43.3– 92.0 ng/ml), the medians were not statistically different (56.4 vs. 53.3 ng/ml). We also measured concentrations of sCD31 in plasma of two patients with MCL before treatment and after three cycles of chemotherapy, and found that the post-chemotherapy levels of sCD31 were lower in both patients (91.8 vs. 60.7 ng/ml; 56.4 vs. 30.4 ng/ml). To investigate the role of CD31 in the biology of MCL we derived JEKO-1 and HBL-2 clones with stable downregulation of CD31 by siRNA approach. In addition, two JEKO-1 subclones with upregulated CD31 were established by limiting dilution from the original cell line (=controls). The limiting dilution approach was not feasible in HBL-2 cells, which completely lack CD31 expression. While HBL-2 clones with downregulated CD31 engrafted constantly, JEKO-1 clones with downregulated CD31 engrafted only in 2 out of 8 mice. Growth of the tumors derived from both HBL-2 and JEKO-1 clones with downregulated CD31 was significantly slower compared to that of control tumors (HBL-2: 2.1±0.4 g versus 4.1±0.2 g, p=0.002; JEKO-1: 0.5±0.1 g versus 2.2±0.2 g, p=0.0019). Xenotransplantation of JEKO-1 clones with upregulated CD31 resulted in accelerated tumor growth compared to controls (3.4±0.2 g versus 2.2±0.2 g, p=0.0027). Importantly, the in vitro proliferation rate between the clones with changed CD31 expression and the original cell lines were not statistically different suggesting that the different growth pattern of tumors was a consequence of altered interaction between the tumor cells and the murine microenvironment. In summary, CD31/PECAM-1 antigen is overexpressed on primary CD19+CD5+ MCL cells obtained from the peripheral blood and bone marrow of MCL patients before therapy compared to control CD19+CD5+ B-cells. The upregulated CD31/PECAM-1 appears to play important role in MCL biology, and might represent potential druggable target. Financial Support: IGA-MZ NT13201-4/2012, GAUK 259211/110709, GAUK 446211, UNCE 204021, PRVOUK P24/LF1/3, PRVOUK 1–5101–280002 PVK, SVV-2012–254260507 Disclosures: No relevant conflicts of interest to declare.

The Chemokine Receptor Profile As Distinctive Criterion Between Normal B-Cell Subsets and As Potential Discriminative Marker to Identify the Cell of Origin in Patients with Chronic Lymphocytic Leukemia and Richter Syndrome

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 3890-3890
Author(s):  
Katharina Troppan ◽  
Kerstin Wenzl ◽  
Peter Neumeister ◽  
Christine Beham-Schmid ◽  
Martina Przekopowitz ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Chemokine Receptor ◽  
Chemokine Receptors ◽  
De Novo ◽  
Memory B Cells ◽  
Cell Of Origin ◽  
Richter Syndrome ◽  
Receptor Profile ◽  
B Cell Subsets

Abstract Chemokine receptors are G-protein-coupled cell surface receptors, which dissociate upon activation by their ligands and cause downstream signaling. Several studies have revealed the crucial contribution of chemokine receptors and their ligands in normal B-cell differentiation and development of hematopoietic malignancies. The Richter syndrome (RS) represents the clinico-pathologic transformation of chronic lymphocytic leukaemia (CLL) to an aggressive lymphoma, most commonly diffuse large B-cell lymphoma (DLBCL). Due to the lack of knowledge on the chemokine receptor, we aimed to investigate their expression profile in patients with CLL and Richter syndrome. Therefore, we investigated the mRNA expression levels of 18 known chemokine receptors (CCR1-CCR9, CXCR1-CXCR7, XCR1, CX3CR1) by using semi-quantitative real-time PCR on seven samples of paired (CLL and transformed DLBCL) RS samples, additionally four CLL samples -all of them subsequently transformed into DLBCL-, and eight transformed DLBCL samples originating from CLL. Additionally, 30 samples of de-novo DLBCL, including 10 germinal center B-cell (GCB) lymphomas, 12 non-germinal center B-cell lymphomas (non-GCB), and 8 unclassified DLBCL were included. Four samples of naïve B-cells (CD5 neg), CD5+ naïve B-cells and CD27+ memory B-cells (n=12) served as non-neoplastic controls. No differences in the chemokine receptor profile were detected between CD5+ and negative naïve B-cells. When comparing CD27+ memory B-cells to naïve B-cells a significant lower expression level was found for CCR7 (7-fold), CXCR4 (4-fold), and CXCR5 (1.5 fold). CCR7 (5-fold) and CXCR4 (5-fold) were also lower expressed in CD27+ memory B-cells compared to CD5+ naïve B-cells. Five out of 18 chemokine receptors were differentially expressed comparing the distinct normal B-cell subsets with RS samples. Comparing CLL samples and RS samples to CD5+ naïve B-cells, CXCR4 (12-fold for CLLs and 10-fold for RS samples) and CXCR5 (2-fold for CLLs and 2.4-fold for RS samples) were lower expressed, whereas CXCR3 (10-fold for CLLs and 8.5-fold for the transformed samples) was higher expressed and CCR5 de-novo expressed. Compared to naïve B-cells, the same chemokine receptors were deregulated: CXCR4 (10-fold for CLLs and 8.5-fold for the RS samples) and CXCR5 (2-fold for CLLs and 2.4-fold for the transformed samples) were lower expressed, CXCR3 (45-fold for CLLs and 30-fold for the transformed samples) was higher expressed and CCR5 was de-novo expressed. Comparing CLL samples and transformed RS samples to CD27+ memory B-cells, CCR5 (5.1-fold for CLLs and 4.3-fold for the RS samples) and CCR7 (8.7-fold for CLLs and 10-fold for the transformed samples) were higher expressed in both malignancies. Only one chemokine receptor was found to be differentially expressed in our seven paired RS samples: CCR6 showed a trend of a higher expression (1.4-fold) in CLL components. Considering RS and GCB DLBCL, CCR1, CCR5, and CXCR6 were found to be significantly down-regulated in RS (at least 4-fold), in contrast to CCR7 and CXCR4, which showed higher expression levels in RS (6-fold). CCR1 and CCR5 were lower expressed comparing RS and non-GCB DLBCL (25-fold and 8-fold), whereas CCR7 again, together with CXCR7, was higher expressed (3- fold and 6-fold respectively). Our data indicate a difference in the chemokine receptor profile within normal B-cell subsets. These differences are also reflected in the different expression profile of low and high aggressive component of CLL/RS compared to the distinct B cell subtypes. Hence, in future these multiple deregulated CC and CXC receptors might serve as a further hint in identifying the cell of origin of different B-cell malignancies. Disclosures No relevant conflicts of interest to declare.

scholarly journals Up-regulation of Lamin A/C Expression in Epstein-Barr Virus Immortalized B Cells and Burkitt Lymphoma Cell Lines of Activated B Cell Phenotype

2016 ◽  
Author(s):  
Ferenc Bánáti ◽  
Anita Koroknai ◽  
Kálmán Szenthe ◽  
Tamás Tereh ◽  
Nóra Kovács ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Cell Lines ◽  
Burkitt Lymphoma ◽  
Epstein Barr Virus ◽  
Cell Phenotype ◽  
Lamin A ◽  
Histone Marks ◽  
Barr Virus ◽  
Epstein Barr

Lamin A, B and C, the nuclear intermediate-filament proteins, play a role in epigenetic regulation. While Lamin B is expressed in all nucleated cells studied, Lamin A/C are transcribed in most somatic cell types except mature B lymphocytes. Since Epstein-Barr virus (EBV), a human gammaherpesvirus, is associated with tumorigenic processes and is known to alter the epigenotype of its host cells, we studied the expression of the LMNA gene and its epigenetic marks in EBV-carrying human lymphoid cell lines. We observed a high lamin A/C mRNA and protein expression in EBV-immortalized lymphoblastoid cell lines (LCLs) and in group III Burkitt lymphoma (BL) lines where hypomethylated first exons were observed with activating histone marks. In most cell lines with low promoter activity a highly methylated first exon could be detected. Our data showed that methylation of the first exon of LMNA was associated with the downregulation of LMNA expression whereas euchromatic histone marks were enriched at active LMNA promoters in EBV-immortalized LCLs. These data suggest a role for viral latency products to activate LMNAp in EBV-infected latency type III B cells in vitro. Expression of lamin A/C may contribute to the establishment of activated B cell phenotype that needs further explorations.

scholarly journals Immunity in Omicron SARS-CoV-2 breakthrough COVID-19 in vaccinated adults

2022 ◽  
Author(s):  
Hassen Kared ◽  
Asia-Sophia Fumika Michaela Wolf ◽  
Amin Alirezaylavasani ◽  
Anthony Ravussin ◽  
Guri Solum ◽  
...  
Keyword(s):  
T Cell ◽  
B Cells ◽  
B Cell ◽  
De Novo ◽  
T Cell Responses ◽  
Affinity Maturation ◽  
T Cell Response ◽  
Memory B Cells ◽  
Viral Escape ◽  
Cell Responses

The new SARS-CoV-2 variant of concern (VOC) Omicron has more than 30 mutations in the receptor binding domain (RBD) of the Spike protein enabling viral escape from antibodies in vaccinated individuals and increased transmissibility. It is unclear how vaccine immunity protects against Omicron infection. Here we show that vaccinated participants at a superspreader event had robust recall response of humoral and pre-existing cellular immunity induced by the vaccines, and an emergent de novo T cell response to non-Spike antigens. We compared cases from a Christmas party where 81 of 110 (74%) developed Omicron breakthrough COVID-19, with Delta breakthrough cases and vaccinated non-infected controls. Omicron cases had significantly increased activated SARS-CoV-2 wild type Spike-specific (vaccine) cytotoxic T cells, activated follicular helper (TFH) cells, functional T cell responses, boosted humoral responses, activated anti-Spike plasmablasts and anti-RBD memory B cells compared to controls. Omicron cases had significantly increased de novo memory T cell responses to non-Spike viral antigens compared to Delta breakthrough cases demonstrating development of broad immunity. The rapid release of Spike and RBD-specific IgG+ B cell plasmablasts and memory B cells into circulation suggested affinity maturation of antibodies and that concerted T and B cell immunity may provide durable broad immunity.

Sign in / Sign up

Export Citation Format

Share Document