VEGF receptor phosphorylation status and apoptosis is modulated by a green tea component, epigallocatechin-3-gallate (EGCG), in B-cell chronic lymphocytic leukemia

Blood ◽  
2004 ◽  
Vol 104 (3) ◽  
pp. 788-794 ◽  
Author(s):  
Yean K. Lee ◽  
Nancy D. Bone ◽  
Ann K. Strege ◽  
Tait D. Shanafelt ◽  
Diane F. Jelinek ◽  
...  
Keyword(s):  
Cell Death ◽  
B Cells ◽  
Chronic Lymphocytic Leukemia ◽  
B Cell ◽  
Annexin V ◽  
Lymphocytic Leukemia ◽  
Parp Cleavage ◽  
Vegf Receptor ◽  
Cell Leukemia ◽  
The Impact

AbstractWe recently reported that chronic lymphocytic leukemia (CLL) cells synthesize and release vascular endothelial growth factor (VEGF) under normoxic and hypoxic conditions. CLL B cells also express VEGF membrane receptors (VEGF-R1 and VEGF-R2), suggesting that they use VEGF as a survival factor. To assess the mechanism of apoptosis resistance related to VEGF, we determined the impact of VEGF on CLL B cells, and we studied the impact of epigallocatechin-3-gallate (EGCG), a known receptor tyrosine kinase (RTK) inhibitor, on VEGF receptor status and viability of CLL B cells. VEGF165 significantly increased apoptotic resistance of CLL B cells, and immunoblotting revealed that VEGF-R1 and VEGF-R2 are spontaneously phosphorylated on CLL B cells. EGCG significantly increased apoptosis/cell death in 8 of 10 CLL samples measured by annexin V/propidium iodide (PI) staining. The increase in annexin V/PI staining was accompanied by caspase-3 activation and poly–adenosine diphosphate ribose polymerase (PARP) cleavage at low concentrations of EGCG (3 μg/mL). Moreover, EGCG suppressed the proteins B-cell leukemia/lymphoma-2 protein (Bcl-2), X-linked inhibitor of apoptosis protein (XIAP), and myeloid cell leukemia-1 (Mcl-1) in CLL B cells. Finally, EGCG (3-25 μg/mL) suppressed VEGF-R1 and VEGF-R2 phosphorylation, albeit incompletely. Thus, these results suggest that VEGF signaling regulates survival signals in CLL cells and that interruption of this autocrine pathway results in caspase activation and subsequent leukemic cell death.

Microenvironment Influences Expression of TOSO – a Novel NF-Kappa B Target Gene In Chronic Lymphocytic Leukemia

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 695-695
Author(s):  
Lukas P. Frenzel ◽  
Alexandra Schulz ◽  
Christian P. Pallasch ◽  
Rainer Claus ◽  
Sabine Ponader ◽  
...  
Keyword(s):  
B Cells ◽  
Chronic Lymphocytic Leukemia ◽  
B Cell ◽  
Target Gene ◽  
Methylation Status ◽  
Lymphocytic Leukemia ◽  
Nf Kappa B ◽  
Over Expression ◽  
Screening Experiments ◽  
The Impact

Abstract Abstract 695 We recently identified the transmembrane protein TOSO to be significantly over-expressed in chronic lymphocytic leukemia (CLL) compared to other B-cell lymphomas or healthy B-cells and T-cells. TOSO was initially characterized as inhibitor of Fas-mediator of apoptosis; however, it could be demonstrated to be the receptor for the IgM-specific Fc-domain in immune cells. TOSO is the only Fcμ receptor expressed on B-cells and is solely expressed in the lymphoid compartment. However, little is known on its regulation and the molecular background of over-expression in CLL. We investigated TOSO expression on mRNA and protein level in freshly isolated primary CLL cells (n=10) and healthy B-cells (n=4) after single treatment for 24 hours with a comprehensive panel of different cytokines or stimuli (interleukin (IL)-1, IL-2, IL-4, IL-6, IL-7, IL-10, IL-12, IL-15, interferon (IFN)-γ, transforming growth factor (TGF)-ß, tumor necrosis factor (TNF)-α, lipopolysaccharide, CpG, CD40-ligand (CD40L) and B-cell receptor (BCR)) being involved in B- and T-cell interplay, by qRT-PCR, western blotting and flow cytometry. Furthermore, we determined the impact of nurse-like cells (NLC) to TOSO expression and co-incubated primary CLL cells for up to 14 days with NLCs. To better understand the intracellular regulation of TOSO, we inhibited BCR and/or CD40L pathways, which were shown by us to be either stimulatory (BCR) or inhibitory (CD40L) in regard to TOSO expression. Since expression might be finally also controlled on epigenetic level, we determined the methylation status of the putative TOSO promoter in 64 CLL samples and 10 healthy B-cells samples. Quantitative DNA methylation analysis was conducted using the EpiTyper application by Sequenom (San Diego, CA, USA). Our experiments reveal novel extra- and intracellular stimuli regulating TOSO expression. We identified CD40L, IL-4 and CpGs to have strong inhibitory effects on TOSO expression (P<0.001) in primary CLL cells and healthy B-cells. In contrast, we identified NLCs (MFIR 15,8 vs. 25,8; P=0.049; n=4) and BCR cross-linking to induce TOSO expression on the cell surface of CLL cells. Based on extracellular stimuli, we were able to hypothesize on shared downstream pathways in order to identify the key regulatory factors and transcription factors controlling TOSO expression. By using a panel of inhibitors in BCR and CD40L downstream signaling, NF-kappa B was shown to have the strongest effect on TOSO expression (P=0,0294). Applying the I-kappa B kinase (IKK) inhibitor Wedelolactone at non-toxic concentrations (10μM), TOSO expression was profoundly suppressed after 24 hours. Regarding epigenetic alterations, our analysis from genome-wide screening experiments in CLL patients compared to healthy B-cells did reveal significant aberrant DNA de-methylation events in the TOSO promoter-associated CpG island (P<0.001). In conclusion, we revealed IL-4, CpG and CD40L as BCR stimulus and NLCs as the key components in regulation of TOSO in the CLL cell microenvironment. Furthermore, over-expression of TOSO in CLL cells compared to normal B-cells could be demonstrated being associated with epigenetic changes at its promoter. We identified TOSO as a novel NF-kappa B regulated target gene. In ongoing studies we elucidate whether NF-kappa B acts directly or in-directly on TOSO expression. Disclosures: No relevant conflicts of interest to declare.

The Novel Proteasome Inhibitor Carfilzomib Functions Independently of p53 to Induce Potent Cytotoxicity in Primary Chronic Lymphocytic Leukemia Cells and a Defective NF-κB Response,

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 3510-3510
Author(s):  
Sneha V. Gupta ◽  
Erin K Hertlein ◽  
Jennifer A. Woyach ◽  
Ellen J. Sass ◽  
Melanie E. Davis ◽  
...  
Keyword(s):  
Cell Death ◽  
Chronic Lymphocytic Leukemia ◽  
Proteasome Inhibitor ◽  
Ex Vivo ◽  
Proteasome Inhibitors ◽  
Lymphocytic Leukemia ◽  
26S Proteasome ◽  
Nuclear Accumulation ◽  
Parp Cleavage ◽  
The Impact

Abstract Abstract 3510 The reversible proteasome inhibitor bortezomib is effective in the treatment of multiple myeloma and mantle cell lymphoma, but failed to produce objective responses in chronic lymphocytic leukemia (CLL). Carfilzomib (CFZ) is a tetrapeptide ketoepoxide that belongs to a new class of irreversible proteasome inhibitors that specifically target the chymotrypsin-like subunit of the 26S proteasome. Based on preclinical data demonstrating potent cytotoxicity in primary CLL cells, CFZ is currently in a phase I clinical trial at The Ohio State University in patients with relapsed or refractory CLL. However, the mechanism of action of CFZ in CLL is unknown. We have therefore investigated the effects of CFZ on CLL patient cells ex vivo. Here we demonstrate that a short (1 hr) exposure of 100 nM CFZ is sufficient to inhibit the chymotrypsin-like proteasome subunit in CLL cells. This exposure is also rapidly cytotoxic, inducing apoptosis in approximately 50% of cells by 24 hr (annexin+ and/or PI+). Unlike bortezomib, the cytotoxicity of carfilzomib is not diminished in media with human serum compared to fetal bovine serum. Additionally, CFZ is more cytotoxic to normal CD19+ B cells than normal CD3+ T cells at clinically relevant concentrations of 33 to 300 nM, suggesting that this agent could potentially avoid immune-suppressing T-cell depletion that is commonly noted with chemotherapy. CFZ causes CLL cell death ex vivo by a caspase-dependent apoptotic pathway, indicated by PARP cleavage and rescue by the broad caspase inhibitor Boc-D-fmk. Importantly, our studies indicate that CFZ causes cytotoxicity in primary CLL cells irrespective of p53 status. This tumor suppressor, which is functional in most CLL patients at the time of diagnosis, is mutated or deleted in at least one allele in approximately 40% of patients with advanced CLL, and p53 pathway dysfunction is associated with resistance to standard therapies and poor overall survival. Therefore, the ability of CFZ to induce apoptosis irrespective of p53 function is of important clinical significance. Additionally, the pro-apoptotic protein Noxa is increased following CFZ treatment despite a lack of induction in mRNA, suggesting accumulation of protein via inhibition of proteasome-mediated degradation. The NF-kB signaling pathway is broadly implicated in CLL cell survival and resistance to therapy, and proteasome inhibitors have been reported to block this pathway via inhibition of IkB degradation. We therefore investigated the impact of CFZ on NF-kB-mediated transcription in CLL patient cells. Paradoxically, our results indicate that CFZ leads to activation of NF-kB, as evidenced by increased nuclear accumulation of the p50 and p65 subunits of NF-kB, as well as phosphorylated IkBα. This correlates with enhanced binding of the p50/p65 heterodimer to an NF-kB probe in an electrophoretic mobility shift assay. However, despite this apparent NF-kB activation, no transcriptional increases were observed in NF-kB targets genes including Mcl-1, p53, Bcl-2, Bcl2A1 or XIAP. In addition, inhibition of NF-kB activity using a dominant negative (non-phosphorylatable) IkBα did not impair CFZ-induced cytotoxicity. This is the first study suggesting that treatment with a proteasome inhibitor induces a defective NF-κB response in CLL cells. The mechanism and relevance of this effect, as well as the pathway by which CFZ causes CLL cell death, continues to be investigated. Collectively, our data indicate that proteasome inhibition is a relevant therapeutic target in CLL and supports the development of carfilzomib for the treatment of this currently incurable disease. Disclosures: No relevant conflicts of interest to declare.

Development of a Transgenic Mouse Model to Study the Role of ZAP-70 in the Development and Progression of Chronic Lymphocytic Leukemia

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 2830-2830
Author(s):  
Stefania Gobessi ◽  
Sara Bennardo ◽  
Pablo G Longo ◽  
Brendan Doe ◽  
Dimitar G Efremov
Keyword(s):  
T Cells ◽  
B Cells ◽  
Chronic Lymphocytic Leukemia ◽  
Mouse Model ◽  
B Cell ◽  
Lymphocytic Leukemia ◽  
Bcr Signaling ◽  
Leukemia Development ◽  
Low Levels ◽  
The Impact

Abstract Abstract 2830 The protein tyrosine kinase ZAP-70 is an important prognostic factor in chronic lymphocytic leukemia (CLL). Patients that are considered ZAP-70-positive typically express 30–100% of the levels of ZAP-70 in T-cells, whereas in the remaining patients ZAP-70 is either not expressed or is expressed at lower levels. ZAP-70-positive patients have more aggressive disease and shorter survival than patients with low or absent ZAP-70. In vitro experiments with human lymphoma cell lines and primary CLL B-cells have shown that ZAP-70 is involved in B cell receptor (BCR) signaling, indicating that overexpression of ZAP-70 could affect the capacity of the leukemic cells to respond to antigen stimulation. Despite the strong association between ZAP-70 expression and prognosis, it is still not clear whether ZAP-70 directly contributes to the aggressiveness of the disease or is just a marker of more aggressive CLL. To further address this issue, we generated transgenic (tg) mice that express different levels of ZAP-70 in B cells. In these mice expression of the murine ZAP-70 transgene is targeted to the B cell compartment by a VH or a CD19 promoter (VH-ZAP70 and CD19-ZAP70 tg mice, respectively). B cells in CD19-ZAP70 tg mice express the same levels of ZAP-70 as normal murine T cells, whereas the levels of ZAP-70 in B cells of VH-ZAP70 tg mice are approximately 10 times lower. Immunophenotyping analysis of spleen and peritoneal cavity samples from wild type, VH-ZAP70 and CD19-ZAP70 tg mice did not reveal significant differences in the percentage of follicular (FO), marginal zone (MZ) and B1 B cells, indicating that ectopic expression of ZAP-70 does not affect normal B cell development and maturation. In terms of BCR signal transduction, no abnormalities were detected in VH-ZAP70 tg mice, suggesting that low levels of ZAP-70 do not affect BCR signaling. In contrast, B cells from CD19-ZAP70 tg mice showed altered phosphorylation of several molecules downstream of the BCR, such as Syk and BLNK, whereas phosphorylation of Cbl was not affected. To investigate the impact of ZAP-70 expression on leukemia development and progression, we crossed VH-ZAP70 and CD19-ZAP70 tg mice with Eμ-TCL1 tg mice. The latter mice develop leukemias that are considered a mouse model of human CLL. These leukemias are CD5+, express unmutated IGHV genes and stereotyped polyreactive BCRs, but are always ZAP-70-negative. VH-ZAP70/Eμ-TCL1 tg mice (n=11) have been followed for over a year and did not show any differences with respect to their Eμ-TCL1 littermates (n=10). Both groups, starting from the age of 7–8 months, developed leukemias with a similar rate of progression and impact on survival, suggesting that low levels of ZAP-70 do not affect the behavior of the disease. The cohort of CD19-ZAP70/Eμ-TCL1 tg mice was more recently established. These animals are currently 4 months old and still do not show signs of leukemia development. Data from the extended follow-up of these mice will be presented at the meeting. Disclosures: No relevant conflicts of interest to declare.

Adaphostin-induced apoptosis in CLL B cells is associated with induction of oxidative stress and exhibits synergy with fludarabine

Blood ◽  
2005 ◽  
Vol 105 (5) ◽  
pp. 2099-2106 ◽  
Author(s):  
Tait D. Shanafelt ◽  
Yean K. Lee ◽  
Nancy D. Bone ◽  
Ann K. Strege ◽  
Ven L. Narayanan ◽  
...  
Keyword(s):  
Cell Death ◽  
B Cells ◽  
Annexin V ◽  
Adenosine Diphosphate ◽  
Lymphocytic Leukemia ◽  
Parp Cleavage ◽  
Ros Generation ◽  
Preclinical Development ◽  
Vitro Analysis

AbstractB-cell chronic lymphocytic leukemia (CLL) is characterized by accumulation of clonal lymphocytes resistant to apoptosis. We evaluated the ability of the investigational antileukemic agent adaphostin to induce apoptosis in CLL B cells and synergize with fludarabine in vitro. Analysis by annexin V/propidium iodide (PI) staining revealed that the concentration of adaphostin required to induce 50% cell death (IC50) at 24 hours was 4.2 μM (range, 1.10-11.25 μM; median, 4.25 μM; n = 29) for CLL isolates and more than 10 μM for B and T cells from healthy donors. Immunoblots demonstrated adaphostin induced poly(adenosine diphosphate-ribose) polymerase (PARP) cleavage and cleavage of caspase-3 substrates, suggesting that adaphostin induces apoptosis. Adaphostin increased the level of reactive oxygen species (ROS) within CLL B cells, and the antioxidant N-acetylcysteine blocked both adaphostin-induced ROS generation and apoptosis. Adaphostin also caused a decrease in the level of the antiapoptotic protein Bcl-2. When adaphostin was combined with fludarabine (F-ARA-AMP), a synergistic effect on cell death was observed in all 10 CLL samples. These findings not only indicate that adaphostin induces apoptosis selectively in CLL B cells through a mechanism that involves ROS generation but also demonstrate its ability to augment the effects of fludarabine. Further preclinical development of adaphostin as a novel agent for the treatment of CLL appears warranted.

Induction of caspase-dependent programmed cell death in B-cell chronic lymphocytic leukemia by anti-CD22 immunotoxins

Blood ◽  
2004 ◽  
Vol 103 (7) ◽  
pp. 2718-2726 ◽  
Author(s):  
Thomas Decker ◽  
Madlene Oelsner ◽  
Robert J. Kreitman ◽  
Giuliana Salvatore ◽  
Qing-cheng Wang ◽  
...  
Keyword(s):  
Cell Death ◽  
B Cells ◽  
Chronic Lymphocytic Leukemia ◽  
Conformational Changes ◽  
Lymphocytic Leukemia ◽  
Interleukin 4 ◽  
Parp Cleavage ◽  
Pseudomonas Exotoxin A ◽  
Bax Protein ◽  
Apoptosis Protein

Abstract B cells of chronic lymphocytic leukemia (CLL) are long-lived in vivo, possibly because of defects in apoptosis. We investigated BL22, an immunotoxin composed of the Fv portion of an anti-CD22 antibody fused to a 38-kDa Pseudomonas exotoxin-A fragment. B cells from 22 patients with CLL were immunomagnetically enriched (96% purity) and were cultured with BL22 or an immunotoxin that does not recognize hematopoietic cells. The antileukemic activity of BL22 was correlated with CD22 expression, as determined by flow cytometry. BL22 induced caspase-9 and caspase-3 activation, poly(adenosine diphosphate [ADP]-ribose)polymerase (PARP) cleavage, DNA fragmentation, and membrane flipping. Cell death was associated with the loss of mitochondrial membrane potential and the down-regulation of Mcl-1 and X-chromosomal inhibitor of apoptosis protein (XIAP). Furthermore, BL22 induced a proapoptotic 18-kDa Bax protein and conformational changes of Bax. Z-VAD.fmk abrogated apoptosis, confirming that cell death was executed by caspases. Conversely, interleukin-4, a survival factor, inhibited spontaneous death in culture but failed to prevent immunotoxin-induced apoptosis. BL22 cytotoxicity was markedly enhanced when combined with anticancer drugs including vincristine. We also investigated HA22, a newly engineered immunotoxin, in which BL22 residues are mutated to improve target binding. HA22 was more active than BL22. In conclusion, these immunotoxins induce caspase-mediated apoptosis involving mitochondrial damage. Combination with chemotherapy is expected to improve the efficacy of immunotoxin treatment. (Blood. 2004;103:2718-2726)

Characterization of Microvesicles in B-Cell Chronic Lymphocytic Leukemia (CLL): A Potential Mediator in CLL B Cell Disease Progression?.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 747-747
Author(s):  
Asish K. Ghosh ◽  
Neil E. Kay
Keyword(s):  
B Cells ◽  
Chronic Lymphocytic Leukemia ◽  
B Cell ◽  
Lymphocyte Count ◽  
Cell Communication ◽  
Annexin V ◽  
Lymphocytic Leukemia ◽  
Disease Stage ◽  
Total Leukocyte Count ◽  
Circular Membrane

Abstract While cellular communication and interactive signaling typically relies on multiple mechanisms including secretion of various growth factors, cytokines, bioactive lipids, and adhesion molecules, we have recently focused on cell-to-cell communication that involves circular membrane vesicles designated as microvesicles (MVs). These are normal constituents of blood plasma released by leukocytes, endothelium, platelets and erythrocytes and are generated by cell activation and growth. In normal serum, the order of MV abundance is platelet-derived (80%), endothelial (10%) and leukocyte-derived (10%) but MV can also be released by malignant cells. The size varies from 0.1–1.0 μm and, MVs express antigens characteristic of the cell of origin, carry other membrane and cytoplasmic constituents and exhibit negatively charged phospholipids (phosphatidylserine) detectable by Annexin V binding. To begin to characterize MV and their potential for communication in CLL, we isolated and characterized MVs from the plasma of chronic lymphocytic leukemia B-cell (CLL B) patients (Rai 0-IV). After isolation from platelet-free plasma, MVs were characterized by flow cytometry for forward and side scatter using 1μm fluorescent beads and stained with Annexin V. Our results suggest that MVs are heterogeneous in size with the majority of MVs within 1μm. Transmission electron microscopy confirmed the size heterogeneity of MVs and exhibited the morphology of the membrane-bound vesicles after phosphotungstic acid staining onto parlodium-coated 300 mesh copper grids. Flow cytometric analysis further demonstrated the presence of CD61 (platelet/megakaryocyte marker), CD19, CD5, CD52, and CD20 on the surface of MV, albeit in differential amounts depending on the stage of the disease and the total leukocyte count. For example, in Rai stage IV (n= 5), we found lesser numbers of MV carrying platelet-derived marker CD61 and more CD19 (41–79%), and CD5 compared to normal MV; 1–5% MV from healthy controls expressed CD19 while Rai stage 4 patients MV expressed CD19 from 41–79%. These results suggest that a significant number of MVs are generated from the leukemic B-lymphocytes in more advanced Rai stage. However, we also found that patients with a higher blood lymphocyte count but lower Rai-stage (Rai I/II) contain moderate levels of CD19-bearing MVs (13–43%). Importantly, presence of MVs carrying CD52/CD20 in the blood of CLL patients may undermine the therapeutic effectiveness of alemtuzumab and rituximab. To this end, we observed that MVs could be incorporated into the CLL B cells as evident from the expression of the platelet antigen CD61 on CLL B cell surfaces after co-culture of CD61-bearing MVs with CLL B cells. Global proteomic analysis of MVs isolated from an advanced stage (Rai IV) CLL B patient detected the presence of about 700 proteins that normally reside in the nucleus, cytoplasm or membrane. In summary, we have isolated and characterized plasma MV from CLL B patients and found them to be more likely generated from CLL B cells in relation to disease stage or total lymphocyte count. These MVs contain a multitude of proteins and are able to integrate into bystander CLL B cells. We also found that these MVs carry a large set of proteins, which could potentially not only modulate cell-cell communication but also interrupt monoclonal antibody directed therapy. Further studies are underway to dissect their roles in CLL B malignancy.

scholarly journals Targeted inhibition of eIF4A suppresses B-cell receptor-induced translation and expression of MYC and MCL1 in chronic lymphocytic leukemia cells

2021 ◽  
Author(s):  
Sarah Wilmore ◽  
Karly-Rai Rogers-Broadway ◽  
Joe Taylor ◽  
Elizabeth Lemm ◽  
Rachel Fell ◽  
...  
Keyword(s):  
B Cells ◽  
Chronic Lymphocytic Leukemia ◽  
B Cell ◽  
Mrna Translation ◽  
Cell Receptor ◽  
Memory B Cells ◽  
B Cell Receptor ◽  
Lymphocytic Leukemia ◽  
Mrna Levels ◽  
Mrna Stabilization

AbstractSignaling via the B-cell receptor (BCR) is a key driver and therapeutic target in chronic lymphocytic leukemia (CLL). BCR stimulation of CLL cells induces expression of eIF4A, an initiation factor important for translation of multiple oncoproteins, and reduces expression of PDCD4, a natural inhibitor of eIF4A, suggesting that eIF4A may be a critical nexus controlling protein expression downstream of the BCR in these cells. We, therefore, investigated the effect of eIF4A inhibitors (eIF4Ai) on BCR-induced responses. We demonstrated that eIF4Ai (silvestrol and rocaglamide A) reduced anti-IgM-induced global mRNA translation in CLL cells and also inhibited accumulation of MYC and MCL1, key drivers of proliferation and survival, respectively, without effects on upstream signaling responses (ERK1/2 and AKT phosphorylation). Analysis of normal naïve and non-switched memory B cells, likely counterparts of the two main subsets of CLL, demonstrated that basal RNA translation was higher in memory B cells, but was similarly increased and susceptible to eIF4Ai-mediated inhibition in both. We probed the fate of MYC mRNA in eIF4Ai-treated CLL cells and found that eIF4Ai caused a profound accumulation of MYC mRNA in anti-IgM treated cells. This was mediated by MYC mRNA stabilization and was not observed for MCL1 mRNA. Following drug wash-out, MYC mRNA levels declined but without substantial MYC protein accumulation, indicating that stabilized MYC mRNA remained blocked from translation. In conclusion, BCR-induced regulation of eIF4A may be a critical signal-dependent nexus for therapeutic attack in CLL and other B-cell malignancies, especially those dependent on MYC and/or MCL1.

scholarly journals COMPARISON OF CHROMOSOMAL REARRANGEMENTS IN BONE MARROW CELLS AND BLAST TRANSFORMED B-CELLS IN RELAPSE OF B-CELL CHRONIC LYMPHOCYTIC LEUKEMIA/ SMALL LYMPHOCYTIC LYMPHOMA

2017 ◽  
Vol 39 (2) ◽  
pp. 141-144
Author(s):  
S V Andreieva ◽  
K V Korets ◽  
O E Ruzhinska ◽  
I M Skorokhod ◽  
O G Alkhimova
Keyword(s):  
Bone Marrow ◽  
B Cells ◽  
Chronic Lymphocytic Leukemia ◽  
B Cell ◽  
Chromosomal Rearrangements ◽  
Lymphocytic Leukemia ◽  
Banding Technique ◽  
Small Lymphocytic Lymphoma ◽  
Detection Frequency ◽  
Cell Chronic Lymphocytic Leukemia

Aim: The genetic mechanisms of resistance to chemotherapy in B-cell chronic lymphocytic leukemia/small lymphocytic lymphoma (B-CLL/SLL) are not clear. We aimed to determine the peculiarities of abnormal karyotype formation in bone marrow (BM) cells and peripheral blood (PB) blast transformed B-cells in relapse of B-CLL/SLL. Materials and Methods: Cytogenetic GTG banding technique and molecular cytogenetic in interphase cells (i-FISH) studies of BM cells and PB blast transformed B-lymphocytes were performed in 14 patients (10 males and 4 females) with B-CLL/SLL. Results: The results of karyotyping BM and PB cells revealed the heterogeneity of cytogenetic abnormalities in combined single nosological group of B-CLL/SLL. In PB B-cells, chromosome abnormalities related to a poor prognosis group were registered 2.5 times more often than in BM cells. Additional near tetraploid clones that occurred in 57.1% cases were the peculiar feature of BM cell karyotypes. Chromosomal rearrangements characteristic of the group of adverse cytogenetic prognosis were revealed in all cases from which in 2 cases by karyotyping BM cells, in 6 cases in PB B-cells and in 8 cases by the i-FISH method in BM cells, i.e. their detection frequency was 3 times higher in PB B-cells and 4 times higher when analyzing by i-FISH in BM cells. Conclusions: Mismatch in abnormal karyotypes in BM and PB B-cells by the presence of quantitative and structural chromosomal rearrangements may be indicative of simultaneous and independent processes of abnormal clone formation in the lymph nodes and BM hematopoietic cells. Accumulation the information about previously unidentified chromosomal rearrangements in relapse of the disease may help to understand the ways of resistance formation to chemotherapy.

scholarly journals Defective T cell-mediated, isotype-specific immunoglobulin regulation in B cell chronic lymphocytic leukemia

Blood ◽  
1988 ◽  
Vol 71 (4) ◽  
pp. 1012-1020 ◽  
Author(s):  
JS Moore ◽  
MB Prystowsky ◽  
RG Hoover ◽  
EC Besa ◽  
PC Nowell
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
Chronic Lymphocytic Leukemia ◽  
B Cell ◽  
Cell Activity ◽  
Lymphocytic Leukemia ◽  
Specific Immunoglobulin ◽  
Cell Chronic Lymphocytic Leukemia

The consistent occurrence of T cell abnormalities in patients with B cell chronic lymphocytic leukemia (B-CLL) suggest that the non- neoplastic host T cells may be involved in the pathogenesis of this B cell neoplasm. Because potential defects of immunoglobulin regulation are evident in B-CLL patients, we investigated one aspect of this by studying the T cell-mediated immunoglobulin isotype-specific immunoregulatory circuit in B-CLL. The existence of class-specific immunoglobulin regulatory mechanisms mediated by Fc receptor-bearing T cells (FcR + T) through soluble immunoglobulin binding factors (IgBFs) has been well established in many experimental systems. IgBFs can both suppress and enhance B cell activity in an isotype-specific manner. We investigated the apparently abnormal IgA regulation in a B-CLL patient (CLL249) whose B cells secrete primarily IgA in vitro. Enumeration of FcR + T cells showed a disproportionate increase in IgA FcR + T cells in the peripheral blood of this patient. Our studies showed that the neoplastic B cells were not intrinsically unresponsive to the suppressing component of IgABF produced from normal T cells, but rather the IgABF produced by the CLL249 host T cells was defective. CLL249 IgABF was unable to suppress IgA secretion by host or normal B cells and enhanced the in vitro proliferation of the host B cells. Size fractionation of both normal and CLL249 IgABF by gel-filtration high- performance liquid chromatography (HPLC) demonstrated differences in the ultraviolet-absorbing components of IgABF obtained from normal T cells v that from our patient with defective IgA regulation. Such T cell dysfunction may not be restricted to IgA regulation, since we have found similar expansion of isotype-specific FcR + T cells associated with expansion of the corresponding B cell clone in other patients with B-CLL. These data suggest that this T cell-mediated regulatory circuit could be significantly involved in the pathogenesis of B-CLL.

Association between the proliferative rate of neoplastic B cells, their maturation stage, and underlying cytogenetic abnormalities in B-cell chronic lymphoproliferative disorders: analysis of a series of 432 patients

Blood ◽  
2008 ◽  
Vol 111 (10) ◽  
pp. 5130-5141 ◽  
Author(s):  
Sandra Quijano ◽  
Antonio López ◽  
Ana Rasillo ◽  
Susana Barrena ◽  
Maria Luz Sánchez ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Cell Lymphoma ◽  
B Cell Lymphoma ◽  
Lymphoproliferative Disorders ◽  
Lymphocytic Leukemia ◽  
Maturation Stage ◽  
Cytogenetic Abnormalities ◽  
M Phase ◽  
The Impact

Abstract Limited knowledge exists about the impact of specific genetic abnormalities on the proliferation of neoplastic B cells from chronic lymphoproliferative disorders (B-CLPDs). Here we analyze the impact of cytogenetic abnormalities on the proliferation of neoplastic B cells in 432 B-CLPD patients, grouped according to diagnosis and site of sampling, versus their normal counterparts. Overall, proliferation of neoplastic B cells highly varied among the different B-CLPD subtypes, the greatest numbers of proliferating cells being identified in diffuse large B-cell lymphoma (DLBCL) and Burkitt lymphoma (BL). Compared with normal B cells, neoplastic B-CLPD cells showed significantly increased S + G2/M-phase values in mantle cell lymphoma (MCL), B-chronic lymphocytic leukemia (B-CLL), BL, and some DLBCL cases. Conversely, decreased proliferation was observed in follicular lymphoma, lymphoplasmacytic lymphoma/Waldenström macroglobulinemia (LPL/WM), and some DLBCL patients; hairy cell leukemia, splenic marginal zone, and MALT-lymphoma patients showed S + G2/M phase values similar to normal mature B lymphocytes from LN. Interestingly, in B-CLL and MCL significantly higher percentages of S + G2/M cells were detected in BM versus PB and in LN versus BM and PB samples, respectively. In turn, presence of 14q32.3 gene rearrangements and DNA aneuploidy, was associated with a higher percentage of S + G2/M-phase cells among LPL/WM and B-CLL cases, respectively.

Sign in / Sign up

Export Citation Format

Share Document