scholarly journals Expression of the c-myc protein is down-regulated at the terminal stages during in vitro differentiation of B-type chronic lymphocytic leukemia cells

Blood ◽  
1991 ◽  
Vol 77 (5) ◽  
pp. 1025-1032 ◽  
Author(s):  
LG Larsson ◽  
M Schena ◽  
M Carlsson ◽  
J Sallstrom ◽  
K Nilsson
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
Plasma Cells ◽  
Terminal Differentiation ◽  
Antigen Expression ◽  
Lymphocytic Leukemia ◽  
Resting Cells ◽  
Ki 67 ◽  
Myc Oncogene ◽  
Myc Gene

Abstract The translocated c-myc oncogene in Burkitt's lymphoma (BL) and murine plasmacytoma (MPC) has been proposed to be expressed at a stage of differentiation at which the gene is normally silent, resulting in a continuous proliferation and an inhibited terminal differentiation. To determine whether c-myc is differently expressed at the various stages of the differentiation pathway, we used B-type chronic lymphocytic leukemia (B-CLL) cells, representing resting B lymphocytes, inducible to proliferation and/or differentiation in vitro. The c-myc protein, and Ig lambda-light chain and PCA-1 antigen as markers of B-cell maturation, were analyzed in single, morphologically defined cells by immunocytochemical double-staining. The proliferation of individual cells was determined by 3H-thymidine incorporation and by analysis of Ki-67 antigen expression. The results show that the level of c-myc expression correlates to the stage of differentiation and to the proliferative activity. Uninduced resting cells did not express c-myc. The c-myc protein was observed in the highest amount at the proliferative B-lymphoblast stage of maturation and was reduced in plasmablasts and undetectable in plasma cells. The results suggest that maturation of B cells into nonproliferative, terminally differentiated plasma cells is associated with a downregulated c-myc expression and thus support the view that the deregulated c-myc gene in BL and MPC is expressed at an inappropriate stage of maturation and thereby inhibits terminal differentiation.

scholarly journals Expression of the c-myc protein is down-regulated at the terminal stages during in vitro differentiation of B-type chronic lymphocytic leukemia cells

Blood ◽  
1991 ◽  
Vol 77 (5) ◽  
pp. 1025-1032
Author(s):  
LG Larsson ◽  
M Schena ◽  
M Carlsson ◽  
J Sallstrom ◽  
K Nilsson
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
Plasma Cells ◽  
Terminal Differentiation ◽  
Antigen Expression ◽  
Lymphocytic Leukemia ◽  
Resting Cells ◽  
Ki 67 ◽  
Myc Oncogene ◽  
Myc Gene

The translocated c-myc oncogene in Burkitt's lymphoma (BL) and murine plasmacytoma (MPC) has been proposed to be expressed at a stage of differentiation at which the gene is normally silent, resulting in a continuous proliferation and an inhibited terminal differentiation. To determine whether c-myc is differently expressed at the various stages of the differentiation pathway, we used B-type chronic lymphocytic leukemia (B-CLL) cells, representing resting B lymphocytes, inducible to proliferation and/or differentiation in vitro. The c-myc protein, and Ig lambda-light chain and PCA-1 antigen as markers of B-cell maturation, were analyzed in single, morphologically defined cells by immunocytochemical double-staining. The proliferation of individual cells was determined by 3H-thymidine incorporation and by analysis of Ki-67 antigen expression. The results show that the level of c-myc expression correlates to the stage of differentiation and to the proliferative activity. Uninduced resting cells did not express c-myc. The c-myc protein was observed in the highest amount at the proliferative B-lymphoblast stage of maturation and was reduced in plasmablasts and undetectable in plasma cells. The results suggest that maturation of B cells into nonproliferative, terminally differentiated plasma cells is associated with a downregulated c-myc expression and thus support the view that the deregulated c-myc gene in BL and MPC is expressed at an inappropriate stage of maturation and thereby inhibits terminal differentiation.

scholarly journals Expression of the c-myc proto-oncogene in multiple myeloma and chronic lymphocytic leukemia: an in situ analysis

Blood ◽  
1991 ◽  
Vol 78 (1) ◽  
pp. 180-191 ◽  
Author(s):  
R Greil ◽  
B Fasching ◽  
P Loidl ◽  
H Huber
Keyword(s):  
Cell Cycle ◽  
Multiple Myeloma ◽  
Chronic Lymphocytic Leukemia ◽  
Peripheral Blood ◽  
Proliferative Activity ◽  
Plasma Cells ◽  
Lymphocytic Leukemia ◽  
Myc Gene ◽  
Gene Transcripts

Abstract The c-myc gene plays a pivotal role in mediating the competence state for cell cycle transversion. This biologic role is in contradiction to reports of elevated expression of the gene in multiple myeloma, a tumor with restricted self-renewal capacity. To more clearly define the role of this gene in plasma cells of myeloma patients, c-myc messenger RNA (mRNA) and/or oncoprotein expression were semiquantitatively analyzed on the single cell level in 19 cases of multiple myeloma, among them 1 biclonal case and 1 case with coexistent chronic lymphocytic leukemia (CLL). Performing anti-sense/mRNA in situ hybridization, mature c-myc gene transcripts were detected in 92% (12 of 13) of cases and could definitely be attributed to the plasma cells by our study. The number of Ki 67-positive plasma cells actively passing the cell cycle was less than 1% and independent of c-myc gene expression. However, because the presence of the 152-c-MYC epitope was correlated to extent of marrow plasmacytosis (r = .64; P = .043) and content of plasmablasts (P = .09), the c-myc gene might serve a function different from proliferative activity, but also associated with tumor cell mass. In CLL cells (21 of 22 cases) and their benign counterparts, ie, bone marrow and peripheral blood lymphocytes, the anti-sense/c-myc mRNA hybridization signals remained below the threshold considered as cutpoint between negative and positive. The low amounts of c-myc transcripts were correlated to neither stage of disease (P = .52) nor lymphocyte counts (P = .24). Because the numbers of peripheral blood lymphoma cells were independent of tumor mass and of c-myc gene transcripts expressed, peripheral blood lymphocytosis might more likely reflect homing processes than proliferative activity in CLL.

scholarly journals EXPRESSION OF LIPOPROTEIN LIPASE AND c-MYC ONCOGENE IN PATIENTS WITH CHRONIC LYMPHOCYTIC LEUKEMIA AFFECTED BY THE CHORNOBYL ACCIDENT

2020 ◽  
Vol 25 ◽  
pp. 421-429
Author(s):  
N. Bilous ◽  
◽  
I. Abramenko ◽  
A. Chumak ◽  
I. Diagil ◽  
...  
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
Lipoprotein Lipase ◽  
Direct Sequencing ◽  
Lymphocytic Leukemia ◽  
Expression Levels ◽  
Myc Oncogene ◽  
Mutational Status ◽  
Ighv Gene ◽  
Lpl Gene ◽  
Myc Gene

Objective. to determine the association between the expression of lipoprotein lipase (LPL) and c-MYC genes in peripheral blood cells of chronic lymphocytic leukemia (CLL) patients affected by the Chornobyl catastrophe depending on the mutational status of IGHV genes. Methods. Analysis was performed in the group of 69 CLL patients irradiated due to the Chornobyl NPP accident (58 clean-up workers of 1986 year, 6 inhabitants of radionuclide contaminated areas, and 5 evacuees). The IGHV gene mutational status was studied by polymerase chain reaction (PCR) followed by direct sequencing. LPL and c-MYC expression was evaluated by Quantitative Real-time PCR. Data were analyzed with the SPSS software package, version 20.0. Results. Relative LPL expression levels in CLL samples ranged from 0 to 1663.5 (mean 138.47 ± 30.69, median 26.1). A strong correlation between individual LPL expression levels and IGHV mutational status was found (r = 0.684; p < 0.0001). The average relative c-MYC expression level was 5.7 ± 0.87 (median 2.86; range 0–48.5). No association between c-MYC expression and IGHV mutational status was found. Among unmutated IGHV cases, a correlation between LPL and c-MYC gene expression levels was identified: r = 0.351; p = 0.013. Conclusions. Our data confirm the dominant concept that unmutated IGHV CLL cases are more sensitive to the action of proliferative stimuli compared to mutated IGHV CLL cases. This is manifested by an increase in the expression of a functionally significant LPL gene, is one for the strongest negative prognostic markers in CLL. Key words: lymphocytic leukemia, LPL, c-MYC, IGHV genes, Chornobyl NPP accident.

Apoptosis or plasma cell differentiation of CD38-positive B-chronic lymphocytic leukemia cells induced by cross-linking of surface IgM or IgD

Blood ◽  
2000 ◽  
Vol 95 (4) ◽  
pp. 1199-1206 ◽  
Author(s):  
Simona Zupo ◽  
Rosanna Massara ◽  
Mariella Dono ◽  
Edoardo Rossi ◽  
Fabio Malavasi ◽  
...  
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
Plasma Cells ◽  
Lymphocytic Leukemia ◽  
Leukemia Cells ◽  
Cross Linking ◽  
Malignant Cells ◽  
Kinase Phosphorylation ◽  
Δ Chain ◽  
Effect Of Surface

Previously, we demonstrated that B-chronic lymphocytic leukemia (B-CLL) cells could be divided into 2 groups depending on the expression of CD38 by the malignant cells. The 2 groups differed in their signal-transducing capacities initiated by cross-linking of surface IgM; only in CD38-positive cells was an efficient signal delivered, invariably resulting in cell apoptosis. In this study, we investigated the effect of surface IgD cross-linking in 10 patients with CD38-positive B-CLL. Exposure of the malignant cells to goat antihuman δ-chain antibodies (Gaδ-ab) caused [Ca++]i mobilization and tyrosine kinase phosphorylation in a manner not different from that observed after goat antihuman μ-chain antibody (Gaμ-ab) treatment in vitro. However, Gaδ-ab-treated cells failed to undergo apoptosis and instead displayed prolonged survival in culture and differentiated into plasma cells when rIL2 was concomitantly present. Cross-linking of surface IgD failed to induce proliferation of the malignant cells in vitro. Moreover, treatment with Gaδ-ab did not prevent apoptosis of B-CLL cells induced by Gaμ-ab. Collectively, these experiments demonstrated that IgM and IgD expressed by the same cell may deliver opposite signals under particular circumstances and provide some clues for the understanding of the pathophysiology of B-CLL.

scholarly journals Expression of the c-myc proto-oncogene in multiple myeloma and chronic lymphocytic leukemia: an in situ analysis

Blood ◽  
1991 ◽  
Vol 78 (1) ◽  
pp. 180-191 ◽  
Author(s):  
R Greil ◽  
B Fasching ◽  
P Loidl ◽  
H Huber
Keyword(s):  
Cell Cycle ◽  
Multiple Myeloma ◽  
Chronic Lymphocytic Leukemia ◽  
Peripheral Blood ◽  
Proliferative Activity ◽  
Plasma Cells ◽  
Lymphocytic Leukemia ◽  
Myc Gene ◽  
Gene Transcripts

The c-myc gene plays a pivotal role in mediating the competence state for cell cycle transversion. This biologic role is in contradiction to reports of elevated expression of the gene in multiple myeloma, a tumor with restricted self-renewal capacity. To more clearly define the role of this gene in plasma cells of myeloma patients, c-myc messenger RNA (mRNA) and/or oncoprotein expression were semiquantitatively analyzed on the single cell level in 19 cases of multiple myeloma, among them 1 biclonal case and 1 case with coexistent chronic lymphocytic leukemia (CLL). Performing anti-sense/mRNA in situ hybridization, mature c-myc gene transcripts were detected in 92% (12 of 13) of cases and could definitely be attributed to the plasma cells by our study. The number of Ki 67-positive plasma cells actively passing the cell cycle was less than 1% and independent of c-myc gene expression. However, because the presence of the 152-c-MYC epitope was correlated to extent of marrow plasmacytosis (r = .64; P = .043) and content of plasmablasts (P = .09), the c-myc gene might serve a function different from proliferative activity, but also associated with tumor cell mass. In CLL cells (21 of 22 cases) and their benign counterparts, ie, bone marrow and peripheral blood lymphocytes, the anti-sense/c-myc mRNA hybridization signals remained below the threshold considered as cutpoint between negative and positive. The low amounts of c-myc transcripts were correlated to neither stage of disease (P = .52) nor lymphocyte counts (P = .24). Because the numbers of peripheral blood lymphoma cells were independent of tumor mass and of c-myc gene transcripts expressed, peripheral blood lymphocytosis might more likely reflect homing processes than proliferative activity in CLL.

KCa3.1 Blockers Inhibit Cell Proliferation in Chronic Lymphocytic Leukemia

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 3887-3887
Author(s):  
Eva M Groessinger ◽  
Lukas Weiss ◽  
Elisabeth Hinterseer ◽  
Judith Schmoelzer ◽  
Karin Oberascher ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
T Cells ◽  
Chronic Lymphocytic Leukemia ◽  
Peripheral Blood ◽  
Lymphocytic Leukemia ◽  
K Channel ◽  
Relative Reduction ◽  
Rt Pcr ◽  
Ki 67

Abstract Abstract 3887 Potassium (K)-channels play an important role in regulating cell proliferation by maintenance of the membrane potential and subsequent Ca2+ signaling. Out of 80 known human K-channel genes only the voltage gated K-channel Kv1.3 and the calcium-gated K-channel KCa3.1 are expressed in lymphocytes, with expression levels varying greatly depending on lymphocyte maturation and activation status (for review see Cahalan MD, Chandy KG, Immunol Rev. 2009). Accordingly, proliferation of various lymphocyte subtypes can be inhibited by blockade of the respective predominant K-channel. As the modulation of K-channel expression on malignantly transformed lymphocytes and their potential as therapeutic targets has been largely overlooked, we characterized the expression and function of Kv1.3 and KCa3.1 in Chronic Lymphocytic Leukemia (CLL). Primary cells from unselected CLL-patients were isolated from peripheral blood mononuclear cells (PBMCs). Comparison of Kv1.3 and KCa3.1 levels on unstimulated CLL-cells versus PMA/ionomycin-activated CLL-cells revealed a significant reduction in the Kv1.3/KCa3.1 ratio (n=31, 1.526 vs. 0.9054, p=0.0005), as evidenced on mRNA and protein levels by RT-PCR and patch clamp analysis, respectively. Stimulation of CLL-cells with enriched and activated autologous CD4+ T-cells resulted in higher CLL-cell activation as measured by CD80/86 expression, and an even more pronounced reduction of the Kv1.3/KCa3.1 ratio. This stimulation protocol also effectively induced CLL-cell proliferation as verified by Ki-67 expression and CFSE dilution via flow cytometric measurement. Highly activated and/or proliferating CLL-cells consistently up-regulated KCa3.1 (RT-PCR: Ki-67 n=5, p=0.0013; CFSE n=5, p=0.0436; immunofluorescence (IF) staining - n=4, p=0.0121), whereas Kv1.3 was fairly low. Consistent with our in vitro data, CLL-cells in lymph node and bone marrow, believed to be primary sites of CLL-proliferation in vivo, were highly positive for KCa3.1 channels in contrast to CLL-cells from the peripheral blood as revealed by IF staining on paraffin-embedded tissue sections. In light of the significantly increased KCa3.1-expression on activated and proliferating CLL-cells, we investigated whether specific blockade of KCa3.1 could inhibit CLL-cell proliferation. CLL-cells in PBMCs were pre-stimulated by co-culture with CD40L expressing (murine) fibroblasts for 24 hours, and were treated with highly specific blockers for KCa3.1 (TRAM-34 or Clotrimazole) or Kv1.3 (PAP-1 or Psora-4) prior to addition of α-CD3/CD28 beads to activate autologous T-cells. KCa3.1 blockade could effectively diminish CLL-cell cycle entry in all samples investigated (TRAM-34: n=12, p<0.0001; Clotrimazole: n=5, p=0.0625) with a mean relative reduction in Ki-67+ cells of 52% (SD=1.56) for TRAM-34 (see Figure left) and 53% (SD=1.11) for Clotrimazole. This antagonizing effect of TRAM-34 was clearly dose-dependent (n=10) without affecting CLL-cell viability (see Figure right) nor activation. Viability, activation and proliferation of T-cells and fibroblasts present in the co-culture system were not affected by TRAM-34. Blockade of Kv1.3 did not reduce proliferation in CLL-cells. In summary, we showed that CLL-cells exhibit significant changes in their K-channel constitution following activation and proliferation, analogous to healthy B-cells. Notably, in vitro CLL-cell proliferation was effectively inhibited by highly specific KCa3.1 blockers. Thus far in vitro testing of potential CLL-drugs has been primarily performed on G0-arrested CLL-cells, sometimes in co-culture with stromal cells to enhance their viability. Our approach attempts to specifically target proliferating CLL-cells, presumably the most relevant CLL-cell fraction contributing to disease progression. Given their low toxicity profile, KCa3.1 blockers could represent a promising therapeutic option in CLL. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Associated chronic lymphocytic leukemia and multiple myeloma: origin from a single clone

Blood ◽  
1985 ◽  
Vol 66 (2) ◽  
pp. 291-293
Author(s):  
JP Fermand ◽  
JM James ◽  
P Herait ◽  
JC Brouet
Keyword(s):  
Multiple Myeloma ◽  
B Cells ◽  
Chronic Lymphocytic Leukemia ◽  
Plasma Cells ◽  
Lymphocytic Leukemia ◽  
Malignant Cells ◽  
Significant Percentage ◽  
Single Clone ◽  
Relationship Of

We investigated the clonal relationship of malignant cells in a patient affected with both chronic lymphocytic leukemia (CLL) and multiple myeloma (MM). CLL cells and malignant plasma cells synthesized IgG1 kappa and IgA kappa molecules, respectively; these monoclonal Ig shared idiotypic determinants, providing evidence that a single clonal disease occurred in this patient. Furthermore, when leukemic CLL cells were driven to differentiate in vitro to immunoblasts and plasma cells, a switch from IgG to IgA occurred in a significant percentage of cells that were double producers. These data suggest that, in some circumstances, CLL leukemic B cells may reach a more mature state, leading to the occurrence of clinical MM.

scholarly journals Associated chronic lymphocytic leukemia and multiple myeloma: origin from a single clone

Blood ◽  
1985 ◽  
Vol 66 (2) ◽  
pp. 291-293 ◽  
Author(s):  
JP Fermand ◽  
JM James ◽  
P Herait ◽  
JC Brouet
Keyword(s):  
Multiple Myeloma ◽  
B Cells ◽  
Chronic Lymphocytic Leukemia ◽  
Plasma Cells ◽  
Lymphocytic Leukemia ◽  
Malignant Cells ◽  
Significant Percentage ◽  
Single Clone ◽  
Relationship Of

Abstract We investigated the clonal relationship of malignant cells in a patient affected with both chronic lymphocytic leukemia (CLL) and multiple myeloma (MM). CLL cells and malignant plasma cells synthesized IgG1 kappa and IgA kappa molecules, respectively; these monoclonal Ig shared idiotypic determinants, providing evidence that a single clonal disease occurred in this patient. Furthermore, when leukemic CLL cells were driven to differentiate in vitro to immunoblasts and plasma cells, a switch from IgG to IgA occurred in a significant percentage of cells that were double producers. These data suggest that, in some circumstances, CLL leukemic B cells may reach a more mature state, leading to the occurrence of clinical MM.

scholarly journals Interleukin 2 stimulates chronic lymphocytic leukemia colony formation in vitro

Blood ◽  
1985 ◽  
Vol 66 (1) ◽  
pp. 237-240 ◽  
Author(s):  
I Touw ◽  
B Lowenberg
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
Colony Formation ◽  
Plasma Cells ◽  
Interleukin 2 ◽  
Colony Growth ◽  
Lymphocytic Leukemia ◽  
Membrane Receptors ◽  
Receptor Expression ◽  
Recombinant Interleukin 2

Abstract The requirements of clonogenic cells of B cell-type chronic lymphocytic leukemia (B CLL) for interleukin 2 (IL 2) were analyzed. Using the cells of five patients, we measured IL 2 receptor expression on the cell surface and the colony-forming abilities of the cells in response to IL 2. In four of the cases, significant percentages of the CLL cells expressed IL 2 membrane receptors (as assessed with the monoclonal antibody anti-Tac), indicative of their potential sensitivity to IL 2. Pure recombinant interleukin 2 (r-IL2) was added to colony cultures that also contained the lectin phytohemagglutinin (PHA) or the phorbol ester 12–0-tetradecanoylphorbol-13-acetate (TPA) to activate the CLL cells. Colony formation completely depended on the presence of r-IL 2 and PHA or TPA in culture, with the exception of one case, in which the addition of IL 2 was not required for colony growth in TPA-supplemented cultures. Twenty-five to fifty units of r-IL 2 per milliliter of culture medium provided optimal stimulation. Under these conditions, a linear relationship was observed between plated cell numbers and colony numbers formed. Morphological and immunologic analysis of colony cells indicated that these were monoclonal CLL cells that had matured toward plasmacellular lymphocytes and plasma cells.

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