Changes in the expression of telomere maintenance genes suggest global telomere dysfunction in B-chronic lymphocytic leukemia

Blood ◽  
2008 ◽  
Vol 111 (4) ◽  
pp. 2388-2391 ◽  
Author(s):  
Delphine Poncet ◽  
Aurélie Belleville ◽  
Claire t'Kint de Roodenbeke ◽  
Aude Roborel de Climens ◽  
Elsa Ben Simon ◽  
...  
Keyword(s):  
B Cells ◽  
Chronic Lymphocytic Leukemia ◽  
Telomere Length ◽  
Expression Pattern ◽  
Prognostic Marker ◽  
Lymphocytic Leukemia ◽  
Telomere Maintenance ◽  
Telomere Dysfunction ◽  
Healthy Donors ◽  
Differential Expression Pattern

In this study, we explored the telomeric changes that occur in B-chronic lymphocytic leukemia (B-CLL), in which telomere length has recently been demonstrated to be a powerful prognostic marker. We carried out a transcriptomic analysis of telomerase components (hTERT and DYSKERIN), shelterin proteins (TRF1, TRF2, hRAP1, TIN2, POT1, and TPP1), and a set of multifunctional proteins involved in telomere maintenance (hEST1A, MRE11, RAD50, Ku80, and RPA1) in peripheral B cells from 42 B-CLL patients and 20 healthy donors. We found that, in B-CLL cells, the expressions of hTERT, DYSKERIN, TRF1, hRAP1, POT1, hEST1A, MRE11, RAD50, and KU80 were more than 2-fold reduced (P < .001), contrasting with the higher expression of TPP1 and RPA1 (P < .001). This differential expression pattern suggests that both telomerase down-regulation and changes in telomeric proteins composition are involved in the pathogenesis of B-CLL.

scholarly journals Telomere Dysfunction in Chronic Lymphocytic Leukemia

2021 ◽  
Vol 10 ◽  
Author(s):  
Billy Michael Chelliah Jebaraj ◽  
Stephan Stilgenbauer
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
Telomere Length ◽  
Clonal Evolution ◽  
Lymphocytic Leukemia ◽  
Telomere Maintenance ◽  
Telomere Dysfunction ◽  
Genomic Complexity ◽  
Multiple Components ◽  
Microenvironmental Factors ◽  
And Function

Telomeres are nucleprotein structures that cap the chromosomal ends, conferring genomic stability. Alterations in telomere maintenance and function are associated with tumorigenesis. In chronic lymphocytic leukemia (CLL), telomere length is an independent prognostic factor and short telomeres are associated with adverse outcome. Though telomere length associations have been suggested to be only a passive reflection of the cell’s replication history, here, based on published findings, we suggest a more dynamic role of telomere dysfunction in shaping the disease course. Different members of the shelterin complex, which form the telomere structure have deregulated expression and POT1 is recurrently mutated in about 3.5% of CLL. In addition, cases with short telomeres have higher telomerase (TERT) expression and activity. TERT activation and shelterin deregulation thus may be pivotal in maintaining the minimal telomere length necessary to sustain survival and proliferation of CLL cells. On the other hand, activation of DNA damage response and repair signaling at dysfunctional telomeres coupled with checkpoint deregulation, leads to terminal fusions and genomic complexity. In summary, multiple components of the telomere system are affected and they play an important role in CLL pathogenesis, progression, and clonal evolution. However, processes leading to shelterin deregulation as well as cell intrinsic and microenvironmental factors underlying TERT activation are poorly understood. The present review comprehensively summarizes the complex interplay of telomere dysfunction in CLL and underline the mechanisms that are yet to be deciphered.

Altered expression pattern of SLAM family receptors on pathological B cells of patients with chronic lymphocytic leukemia

2016 ◽  
Vol 58 (7) ◽  
pp. 1726-1729 ◽  
Author(s):  
Matus Coma ◽  
Elena Tothova ◽  
Tomas Guman ◽  
Martina Hajikova ◽  
Maria Giertlova ◽  
...  
Keyword(s):  
B Cells ◽  
Chronic Lymphocytic Leukemia ◽  
Expression Pattern ◽  
Lymphocytic Leukemia ◽  
Altered Expression ◽  
Altered Expression Pattern ◽  
Slam Family

scholarly journals Enhanced levels of both the membrane-bound and soluble forms of IgM Fc receptor (FcμR) in patients with chronic lymphocytic leukemia

Blood ◽  
2011 ◽  
Vol 118 (18) ◽  
pp. 4902-4909 ◽  
Author(s):  
Fu Jun Li ◽  
Yoshiki Kubagawa ◽  
Matthew K. McCollum ◽  
Landon Wilson ◽  
Tomoko Motohashi ◽  
...  
Keyword(s):  
T Cells ◽  
B Cells ◽  
Chronic Lymphocytic Leukemia ◽  
Cell Surface ◽  
Fc Receptor ◽  
Lymphocytic Leukemia ◽  
Soluble Form ◽  
Spectrometric Analysis ◽  
Healthy Donors ◽  
Membrane Bound

Abstract The association of an IgM-Fc receptor (FcμR) with chronic lymphocytic leukemia (CLL) was suggested more than 30 years ago, but its authenticity has never been formally addressed. We examined the expression of the recently identified FcμR by B and T cells in CLL patients using receptor-specific monoclonal antibodies. CLL B cells (CD5+/CD19+) expressed much higher levels of FcμR on their cell surface than B cells from healthy donors. Such enhanced expression was more evident in immunoglobulin heavy chain variable region (IGHV)–mutated, CD38− or early Rai-stage CLL than in IGHV-unmutated, CD38+, or advanced Rai-stage CLL. Intriguingly, surface FcμR levels also were significantly elevated in the non-CLL B cells (CD5−/CD19+) and T cells (CD5+/CD19−), especially in IGHV-mutated CLL. CLL patients also had high serum titers of FcμR compared with healthy donors, and serum FcμR levels correlated significantly with circulating lymphocyte numbers but not with the IGHV mutation status or Rai stage. The serum FcμR was resolved as an ∼ 40-kDa protein, distinct from the cell surface FcμR of ∼ 60 kDa, and it was produced by both CLL B and non-CLL B cells. Mass spectrometric analysis revealed that the serum FcμR is a soluble form of the receptor encoded by an alternatively spliced FcμR transcript. These findings indicate enhanced levels of both membrane-bound and soluble forms of FcμR in CLL patients.

Telomeric damage in early stage of chronic lymphocytic leukemia correlates with shelterin dysregulation

Blood ◽  
2011 ◽  
Vol 118 (5) ◽  
pp. 1316-1322 ◽  
Author(s):  
Adeline Augereau ◽  
Claire T'kint de Roodenbeke ◽  
Thomas Simonet ◽  
Serge Bauwens ◽  
Béatrice Horard ◽  
...  
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
Time Course ◽  
Early Stage ◽  
Deep Understanding ◽  
Lymphocytic Leukemia ◽  
Telomere Dysfunction ◽  
Chromosome Fusion ◽  
Telomere Shortening ◽  
Healthy Donors ◽  
Binet Stage

Abstract Cells of B-cell chronic lymphocytic leukemia (B-CLL) are characterized by short telomeres despite a low proliferative index. Because telomere length has been reported to be a valuable prognosis criteria, there is a great interest in a deep understanding of the origin and consequences of telomere dysfunction in this pathology. Cases of chromosome fusion involving extremely short telomeres have been reported at advanced stage. In the present study, we address the question of the existence of early telomere dysfunction during the B-CLL time course. In a series restricted to 23 newly diagnosed Binet stage A CLL patients compared with 12 healthy donors, we found a significant increase in recruitment of DNA-damage factors to telomeres showing telomere dysfunction in the early stage of the disease. Remarkably, the presence of dysfunctional telomeres did not correlate with telomere shortening or chromatin marks deregulation but with a down-regulation of 2 shelterin genes: ACD (coding for TPP1; P = .0464) and TINF2 (coding for TIN2; P = .0177). We propose that telomeric deprotection in the early step of CLL is not merely the consequence of telomere shortening but also of shelterin alteration.

Homeostatic Proliferation of Chronic Lymphocytic Leukemia.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 2954-2954
Author(s):  
Stefan Wirths ◽  
Antonio Lanzavecchia
Keyword(s):  
B Cells ◽  
Chronic Lymphocytic Leukemia ◽  
Terminal Differentiation ◽  
Human Memory ◽  
Memory B Cells ◽  
Lymphocytic Leukemia ◽  
Homeostatic Proliferation ◽  
Turnover Rates ◽  
Healthy Donors

Abstract Slow accumulation of chronic lymphocytic leukemia cells in vivo was considered due to defective apoptosis rather than proliferation. However, recent data, based on isotope incorporation studies, suggested significant continuous proliferation of CLL cells in vivo and similar observations has been made for human memory B cells. As previous gene expression studies revealed close relation of CLL cells to memory B cells we asked, whether the mechanisms driving homeostatic proliferation of human memory B cells were stimulating CLL cells as well. Comparison of CLL samples (n=20) and memory B cells of healthy donors showed high expression levels of Toll-like receptor (TLR) 7 and TLR9 and of IL2 and IL15 cytokine receptors compared to naive B cells. Proliferation of CLL cells compared to their normal counterparts was analyzed after FACS sorting and CFSE-labeling.Naive B cells did neither respond to TLR7 ligand resiquimod, TLR9 ligand CpG2006, IL2 and IL15 nor to their combination. In contrast, CLL cells and memory B cells showed comparable patterns of proliferation. Remarkably, under these conditions, terminal differentiation to plasma cells was observed for memory B cells only, while proliferation of CLL ceased after the 4th division without differentiation into Ig-secreting cells. To estimate in vivo turnover rates, B cells of healthy donors and CLL cells were stained for intracellular Ki67, that identifies recently divided cells, and were analyzed by flow cytometry. Memory B cells showed high in vivo turnover rates (2–5% Ki67+) while naive B cells where largely quiescent - results that are in line with previous isotope incorporation studies with healthy donors. Turnover rates of CLL ex vivo ranged from 0.025–1.4% Ki67+ cells, which in absolute numbers (per mL of blood) was comparable to memory B cells. These results are consistent with a concept of homeostatic proliferation of both memory B cells and CLL cells, the latter being arrested without terminal differentiation, which might account for their accumulation in vivo.

Remarkable Differences in Cellular Activation State and Migratory and Proliferative Potential among Clonal Cells Derived from Different Tissues of Chronic Lymphocytic Leukemia Patients.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 2817-2817
Author(s):  
Rajendra N. Damle ◽  
Taraneh Banapour ◽  
Sonal Temburni ◽  
Tarun Wasil ◽  
Jonathan E. Kolitz ◽  
...  
Keyword(s):  
Bone Marrow ◽  
B Cells ◽  
Chronic Lymphocytic Leukemia ◽  
Telomere Length ◽  
Telomerase Activity ◽  
Lymphocytic Leukemia ◽  
Proliferative Potential ◽  
Activation Markers ◽  
Cellular Activation ◽  
Cd38 Expression

Abstract An antigen-independent process that takes place in the bone marrow (BM) leads to the birth of B cells from bone marrow precursors. Cross-talk between components of the microenvironment of BM or secondary lymphoid compartment(s), eg. spleen (SP), nurtures the subsequent evolution of B cells and governs in large part the natural history of normal B cells and B cell malignancies including chronic lymphocytic leukemia (B-CLL). Interaction of B cells with stromal elements confers upon them features enabling their transient sequestration, proliferation and extended survival. In this report we have compared the characteristics of clonal B-CLL cells obtained from paired specimens (peripheral blood, PB with corresponding BM or SP obtained within an interval of less than 1 month of each other) from 17 individual untreated B-CLL patients. These cells were tested by surface immunofluorescence and flow cytometry for their expression of a panel of chemokine receptors (CCR −1, −2, −4, and −7 and CXCR−1, −2, −3, and −4) and markers of cellular activation (CD23, CD62L, CD69, CD71 and HLA-DR). The relative age of the B cells (telomere length) and their ability to maintain telomere length (telomerase activity) were studied in paired BM/SP and PB samples from 15 of these cases. Although PB-, BM- and SP-derived B cells expressed activation markers, specifically, the percentages of cells expressing ZAP-70 and Ki-67 were significantly higher in BM- and SP-derived B cells than those expressed by corresponding PB-derived B cells (p<0.01). Increase in extent of CD38-positivity among members of the clone correlates with poor prognosis in B-CLL. Interestingly, in cases with low CD38 expression (<30% cells expressing CD38), the percentage of B-CLL cells expressing CXCR3 and CCR7 was significantly higher among PB-B cells, than BM/SP-derived B cells. No such differences existed in cases with high CD38 expression. This suggests a role for these receptors and their ligands in maintaining homeostasis of B-CLL cells in this subset of cases (that does not show remarkable progression of disease). In each of the 15 cases studied BM and SP-B cells had significantly higher telomerase activity (p<0.01) than those in PB, although telomere lengths of B cells from both sources were comparable. These findings highlight important differences in cellular kinetics among lymphoid compartments in B-CLL.

Significantly Shorter Telomeres in T-Cells of ZAP-70+/CD38+ Patients with Chronic Lymphocytic Leukemia (CLL): An Important Role of T-Cells in This Subgroup of CLL?.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 1120-1120
Author(s):  
Alexander Roeth ◽  
Dirk de Beer ◽  
Holger Nueckel ◽  
Ludger Sellmann ◽  
Ulrich Duehrsen ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
Chronic Lymphocytic Leukemia ◽  
Telomere Length ◽  
Memory T Cells ◽  
Lymphocytic Leukemia ◽  
Healthy Individuals ◽  
Cell Numbers

Abstract BACKGROUND: In contrast to other B-cell neoplasias, chronic lymphocytic leukemia (CLL) is not only characterized by a clonal expansion of specific B-cells, but also by an increase in non-leukemic T-cells, most likely involved in sustaining the growth of the leukemic B-cell clone. Based on ZAP-70, CD38 and the IgVH mutation status, two prognostic groups of CLL patients can be identified. Our aim was to characterize the replicative histories of the B- and T-cells in the two groups of CLL patients compared to healthy individuals. PATIENTS and METHODS: Blood samples from 73 patients with CLL (ZAP-70−/CD38−: n = 29, ZAP-70+/CD38+: n = 30, ZAP-70/CD38 discordant: n = 14) were analyzed. The quantity and characteristics of the lymphocyte subsets was assessed by a cell counter and by immunophenotypic analysis. The replicative histories of naive and memory T-cells as well as B-cells was determined by measurements of telomere length in peripheral blood leukocytes of CLL patients and healthy individuals by automated multicolor flow-FISH. RESULTS: As expected, the average telomere length of the clonal B-cells was short. The telomere length was, however, significantly shorter for the ZAP-70+/CD38+ patient samples (2.46 ± 1.08 kb) than for the ZAP-70−/CD38− patient samples (5.06 ± 1.76 kb, p < 6.7 x 10−9). Interestingly, also the naive and memory T-cells from ZAP-70+/CD38+ CLL patients exhibited significantly shorter average telomere lengths (mean ± std: 4.85 ± 1.58 kb; 4.39 ± 1.09 kb) than T-cells from ZAP-70−/CD38− CLL patients (6.64 ± 1.72 kb, p < 2.2 x 10−4; 6.22 ± 1.5 kb, p < 7.4 x 10−6). These results are in line with the observed higher absolute T-cell numbers in the ZAP-70+/CD38+ CLL patients compared to ZAP-70−/CD38− CLL patients. Moreover, the average telomere loss in relation to time from primary diagnosis to sample date was higher for naive T-cells than memory T-cells in ZAP-70+/CD38+ patients (7.8 vs. 5.8 bp/month). When we compared the telomere length to age-related percentiles calculated from over 400 healthy individuals aged 0–102 years practically all telomere length values of the naive and memory T-cells from the ZAP-70+/CD38+ CLL patients fell below the 50th percentile, whereas the values of naive and memory T-cells from the ZAP-70−/CD38− CLL patients were within the normal distribution. CONCLUSIONS: We can confirm significantly shorter telomere length values for the B-cells of the ZAP-70+/CD38+ CLL patients. In addition, we can also demonstrate significantly shorter telomeres in T-cells of ZAP-70+/CD38+ CLL patients, which are below the 50th percentile compared to controls, and a higher telomere loss over time for naive T-cells of ZAP-70+/CD38+ CLL patients. As telomere length shortens approximately 50 to 100 bp per cell division the observed decrease in telomere length of the T-cells in ZAP-70+/CD38+ CLL patients equals to approximately 18 to 36 population doublings. This is by far more than expected by the slightly higher T-cell numbers in the peripheral blood. Our observations imply an extensive expansion of the T-cell compartment in ZAP-70+/CD38+ CLL patients and suggest an important role of T-cells in this subgroup of CLL patients.

Mechanisms of Telomere Maintenance Dysfunction in B-Chronic Lymphocytic Leukemia Through CpG Island Methylation

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 3489-3489 ◽  
Author(s):  
Morgan Auchter ◽  
Sandrine Medves ◽  
Laetitia Chambeau ◽  
Sophie Gazzo ◽  
Etienne Moussay ◽  
...  
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
Telomere Length ◽  
Dna Sequences ◽  
Conflicts Of Interest ◽  
Cpg Island ◽  
Methylation Status ◽  
Telomerase Activity ◽  
Lymphocytic Leukemia ◽  
Telomere Maintenance ◽  
Cpg Island Methylation

Abstract Abstract 3489 Telomeres are a repetitive DNA sequences associated with a protein complex named shelterin that protect chromosome ends. Two types of mechanisms maintain telomere in cancer cells. The first involves telomerase an enzyme able to copy the telomeric motif that consists of three principal subunits, including the telomerase reverse transcriptase hTERT. The second, named ALT (Alternative Lengthening of Telomere), corresponds to the recombination between telomeres that involves notably a complex formed by the topoisomerase III alpha (hTopoIIIa), BLM, RMI1 and RMI2. Little is known about the involvement of the ALT mechanism in B-chronic lymphocytic leukemia (B-CLL). In fact this leukemic disease shows low telomerase activity, shelterin defect and telomeric dysfunction. In an effort to characterize ALT cells from 31 B-CLL patients, we analyzed their telomere length and telomerase activity. B-CLL patients showed almost no hTERT transcript (detected in three cases), low telomerase activity (detected in 7 cases) and a telomere average size ranging from 3 to 10 kb. Moreover, a strong deregulation of genes encoding three shelterin proteins, TRF1, TRF2, Pot1, and an at least two fold downregulation of hTopoIIIa gene expression in 21 cases were observed, suggesting the presence of a telomere maintenance dysfunction affecting both mechanisms, telomerase dependent and ALT. CpG island methylation has been mapped for both promoters and if hTERT shows a disseminated methylation profile in 22 patients, for hTopoIIIα we identified nine CpG upstream the minimal promoter, being methylated in 19 of our 31 analyzed patients. We then performed luciferase experiments and we showed that methylation in this 9 CpG induced a strong inhibition of hTopoIIIa transcription. Finally we correlated telomere length and hTopoIIIa methylation status as we observed that 25.4% of the hTopoIIIa promoters were methylated in patients with shorter chromosomes and only 11.1 % were methylated in patients with longer telomeres (p<0.0025). As nearly no telomerase activity have been detected in our patients and as downregulation of hTopoIIIa could increase recombination rate between sister chromatid, methylation of hTERT and hTopoIIIa promoter CpG islands may lead to telomere dysfunction and increased genetic instability in B-CLL. Disclosures: No relevant conflicts of interest to declare.

scholarly journals MiR-181b in Chronic Lymphocytic Leukemia B Cells Is Regulated By Cellular Interaction with CD4+ T Cells and Increases the CTL Toxicity Versus the Leukemic Clone

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 4134-4134
Author(s):  
Mirco di Marco ◽  
Serena Veschi ◽  
Rosa Visone ◽  
Giuseppe Leone ◽  
Paola Lanuti ◽  
...  
Keyword(s):  
T Cells ◽  
B Cells ◽  
Chronic Lymphocytic Leukemia ◽  
Cd4 T Cells ◽  
Lymphocytic Leukemia ◽  
Healthy Donors ◽  
Leukemic Clone

Abstract Clinical progression of chronic lymphocytic leukemia (CLL) is characterized by gradual reduction of the ratio T/B cells, along with immune cell dysfunction due, at least in part, to T cell defects, such as decreased expression of CD40L and reduced signaling via the TCR CD3. This compromise the ability of T cells to respond and to eliminate leukemic cell from CLL patients. Enhanced activation of either allogenic or autologous T cells can drive the death of CLL cells in vitro and in human subjects. Changes in microRNAs expression also characterize clinical progression of CLL with a strong decrease of miR-181b/a and miR-130a associated with the more aggressive phase of the disease. The miR-181b targets anti-apoptotic proteins, such as BCL-2 and MCL1 and its expression correlates with those protein levels in CLL. In this study we demonstrate that the expression of those microRNAs in CLL-B cells, are regulated by T cells. We co-cultured allogenic pure CLL-B cells with either activated (CD2, CD3 and CD28 antibodies, used to mimic antigen-presenting cells) or not activated CD4+ T cells from healthy donors. We observed a significant increase of mir-181b/a and miR-130a expression in CLL B-cells after co-culture with activated CD4+ T cells in 8 out of 11 cases. A significant increase of these miRs was also determined in purified CLL B-cells after 4 days activation of peripheral blood mononuclear cells (PBMCs) from CLL patients, even if in minor rate. By the use of specific antibodies, co-culture with Hela CD40 expressing cells and transwell experiments, we established that this effect is a T/B contact-dependent signaling mediated through CD40L-CD40 interaction. We determine that increased expression of the 3 miRs occurs at the transcriptional level. Since the expression of miR-181b showed the most significant variation in previous experiments it was selected for further analyses. We next investigated the in vivo role of the miR-181b in highly immunodeficient mice. The CLL cell line, MEC-01, infected with either the LV-miR-181b_coGFP or the LV-CTRL_coGFP was intravenously inoculated in NOD.Cg-Prkdcscid Il2rgtm1Wjl/SzJ (NSG) mice. Mice were sacrificed after 4 weeks and assayed for percentage of GFP+ cells in bone marrow and spleen compartments. The miR-181b did not show any specific effect into the leukemic clone. However when the same cells were inoculated in an environment hosting mature T cells, miR-181b consistently influences the death of leukemic cells (Fig 1B), suggesting that T cells are required to potentiate the apoptotic role of this miRNA. To explain what we observed in vivo, we mixed in vitro MEC-01 infected with either the LV-miR-181b or the LV-CTRL and CD8+ T cells from healthy donors. After few hours of contact T cells showed stronger cytotoxic effect on MEC-01 carrying miR-181b as compared to the control. Mixed lymphocyte reaction CD40L-activated CLL and T cells is used to generate effector CTLs. Therefore we grew T cell with CD40L-activated MEC-01 in which the expression of miR-181b was either shut down by lentiviral vector or unchanged as control. After one week, we monitored by cytofluorimetry the CD38 surface marker on T cells since its expression has been associated with more active CTLs and, by ELISA, the release of IL-10, the inhibitor of the potent inducer of CTLs INF-g. We demonstrate that activated MEC-01 with higher expression of miR-181b leads to an increase of the cell number expressing CD38 and this was accompanied by a reduced release of IL-10 from B cells through down-regulation of c-FOS, which we show to be target of the miR-181b and to promote the transcription of the IL-10. In conclusion, our data suggest a role of the miR-181b in the immune response against CLL-B cells. We show that an efficient activation of CD4+ T cells through CD3-complex pathway and a right CD40L-CD40 interaction lead to a significant increase of the some miRNAs deregulated over the progression of chronic lymphocytic leukemia, namely miR-181b. This miRNA potentiates the cytotoxicity of T cells favoring the killing of the leukemic clone. Disclosures No relevant conflicts of interest to declare.

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