Lymphoid Microenvironment Inhibits Apoptosis in B-CLL Cells: Involvement of PI3-K/AKT Pathway and PTEN.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 1443-1443
Author(s):  
Medhat Shehata ◽  
Susanne Schnabl ◽  
Dita Demirtas ◽  
Josef D. Schwarzmeier ◽  
Martin Hilgarth ◽  
...  
Keyword(s):  
Lymphocytic Leukemia ◽  
Negative Regulator ◽  
Leukemic Cells ◽  
Prolonged Survival ◽  
Akt Pathway ◽  
Tail Domain ◽  
Stromal Fibroblasts ◽  
Apoptotic Effect ◽  
Induced Apoptosis

Abstract The activation of anti-apoptotic mechanisms in the leukemic B cells in chronic lymphocytic leukemia (B-CLL) through the interaction with their microenvironment may lead to prolonged survival and the accumulation of the malignant clone. The aim of this study is to elucidate the influence of the lymphoid microenvironment in the activation of the potent anti-apoptotic PI3-K/Akt pathway and to investigate the pattern of expression of the tumor suppressor PTEN in B-CLL. Stromal fibroblasts of bone marrow (BMF), spleen (SF) and lymph gland (LGF) were used as an in vitro model for lymphoid microenvironment. Pharmacological inhibitors and siRNAs against PI3-K and Akt were applied to explore the anti-apoptotic effect of this pathway in B-CLL. The results showed that co-cultivation of B-CLL cells with human BMF, LGF, and SF significantly inhibited apoptosis and prolonged survival of the leukemic cells in comparison to suspension cultures. To explore the involvement of PI3-K/Akt pathway in the anti-apoptotic effect of stromal fibroblasts, co-cultures were performed in presence of PI3-K inhibitors (wortmannin or LY294002) or siRNAs against PI3-K and Akt1. These inhibitors significantly reduced the supportive effect of stromal fibroblasts and induced apoptosis in B-CLL cells. The leukemic cells were more sensitive to PI3-K inhibition than T cells, monocytes and stromal fibroblasts. Induction of apoptosis was associated with a significant decrease in the intracellular levels of PIP3, PI3-K, PDK1, Akt1, NF-kappa B, IKK, and dephosphorylation (activation) of PTEN. Since PTEN activity, as a negative regulator for PI3-K signalling, is controlled by its phosphorylation at the tail domain, we studied the pattern of PTEN protein expression in B-CLL. Western blotting demonstrated that the total PTEN in PBMC of B-CLL patients (n=40) is comparable to healthy individuals (n=8). However, using phosphospecific anti-PTEN antibody demonstrated that samples of B-CLL patients highly express phosphorylated (inactive) forms of PTEN in comparison to healthy persons. In conclusion, the results demonstrate that PI3-K/Akt pathway is involved in inhibition of apoptosis of B-CLL cells and suggest that interaction of the leukemic cells with lymphoid microenvironment may lead to the activation of this pathway. The data also suggest that targeting this pathway represents a feasible therapeutic approach in B-CLL.

Interaction between B-CLL Cells and Lymphoid Microenvironment Leads to Activation of PI3-K/Akt Pathway and Inhibition of Apoptosis.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 2102-2102
Author(s):  
Medhat Shehata ◽  
Susanne Schnabl ◽  
Dita Demirtas ◽  
Josef D. Schwarzmeier ◽  
Martin Hilgarth ◽  
...  
Keyword(s):  
Cell Interaction ◽  
Lymphocytic Leukemia ◽  
Leukemic Cells ◽  
Akt Pathway ◽  
Nf Kappa B ◽  
Stromal Fibroblasts ◽  
Apoptotic Effect ◽  
Induced Apoptosis ◽  
Novel Therapeutic Strategies

Abstract Inhibition of apoptosis and long survival leads to accumulation of the leukemic cells in B cell chronic lymphocytic leukemia (B-CLL). This could be due to activation of anti-apoptotic cascades in CLL cells through interaction with their lymphoid microenvironment. Therefore, we investigated the role of tumor microenvironment in prolongation of survival of B-CLL cells and activation of the potent anti-apoptotic PI3-K/Akt pathway. Stromal fibroblasts of bone marrow (BMFs), spleen (SF) and lymph gland (LGF) were used as an in vitro model for lymphoid microenvironment and we tested their ability to inhibit spontaneous apoptosis of B-CLL cells. Co-culture of B-CLL cells with human BMFs, LGF, and SF significantly inhibited apoptosis and prolonged survival of the leukemic cells in comparison to suspension cultures and to co-cultures with fibroblasts obtained from non-lymphoid organs. Trans-well culture experiments indicated that cell-cell interaction and soluble mediators are essential for this supportive effect. To explore the involvement of PI3-K/Akt pathway in the anti-apoptotic effect of stromal fibroblasts, co-cultures were performed in presence of PI3-K inhibitors (wortmannin or Ly294002) or siRNAs against PI3-K (p110ß subunit) and Akt1. These inhibitors significantly reduced the supportive effect of stromal fibroblasts and induced apoptosis in B-CLL cells. Interestingly, the leukemic cells were far more sensitive to PI3-K inhibition than T cells, monocytes and fibroblasts. Induction of apoptosis was associated with a significant decrease in the intracellular PIP3, PI3-K, PDK1 and Akt1, NF-kappa B, IKK and de-phosphorylation/activation of tumor suppressor protein PTEN. Studies using phosphospecific anti-PTEN antibody demonstrated that PBMC of CLL patients (n=40) highly express a phosphorylated form of PTEN. The results demonstrate that the PI3-K/Akt pathway is involved in inhibition of apoptosis of B-CLL cells and suggest that interaction of the leukemic cells with lymphoid microenvironment maintains the activation of this pathway. The data also suggest that targeting this pathway represents a new option for designing novel therapeutic strategies in B-CLL.

scholarly journals Oridonin, a diterpenoid extracted from medicinal herbs, targets AML1-ETO fusion protein and shows potent antitumor activity with low adverse effects on t(8;21) leukemia in vitro and in vivo

Blood ◽  
2006 ◽  
Vol 109 (8) ◽  
pp. 3441-3450 ◽  
Author(s):  
Guang-Biao Zhou ◽  
Hui Kang ◽  
Lan Wang ◽  
Li Gao ◽  
Ping Liu ◽  
...  
Keyword(s):  
Fusion Protein ◽  
Target Genes ◽  
Critical Role ◽  
Ectopic Expression ◽  
Medicinal Herbs ◽  
Leukemic Cells ◽  
Apoptotic Effect ◽  
Induced Apoptosis

Abstract Studies have documented the potential antitumor activities of oridonin, a compound extracted from medicinal herbs. However, whether oridonin can be used in the selected setting of hematology/oncology remains obscure. Here, we reported that oridonin induced apoptosis of t(8;21) acute myeloid leukemic (AML) cells. Intriguingly, the t(8;21) product AML1-ETO (AE) fusion protein, which plays a critical role in leukemogenesis, was degraded with generation of a catabolic fragment, while the expression pattern of AE target genes investigated could be reprogrammed. The ectopic expression of AE enhanced the apoptotic effect of oridonin in U937 cells. Preincubation with caspase inhibitors blocked oridonin-triggered cleavage of AE, while substitution of Ala for Asp at residues 188 in ETO moiety of the fusion abrogated AE degradation. Furthermore, oridonin prolonged lifespan of C57 mice bearing truncated AE-expressing leukemic cells without suppression of bone marrow or reduction of body weight of animals, and exerted synergic effects while combined with cytosine arabinoside. Oridonin also inhibited tumor growth in nude mice inoculated with t(8;21)-harboring Kasumi-1 cells. These results suggest that oridonin may be a potential antileukemia agent that targets AE oncoprotein at residue D188 with low adverse effect, and may be helpful for the treatment of patients with t(8;21) AML.

scholarly journals Towards the Application of Atorvastatin to Intensify Proapoptotic Potential of Conventional Antileukemic AgentsIn Vitro

2015 ◽  
Vol 2015 ◽  
pp. 1-11
Author(s):  
Jolanta D. Żołnierczyk ◽  
Arleta Kaźmierczuk ◽  
Paweł Hikisz ◽  
Barbara Cebula-Obrzut ◽  
Ewa Wawrzyniak ◽  
...  
Keyword(s):  
Standard Treatment ◽  
Therapeutic Option ◽  
Combined Treatment ◽  
Lymphocytic Leukemia ◽  
Leukemic Cells ◽  
Treatment Results ◽  
High Concentrations ◽  
High Doses ◽  
Induced Apoptosis

It has been previously revealed that statins used at high concentrations display antileukemic potential towards chronic lymphocytic leukemia (CLL) cells. However, their usage alone in clinical practice may be limited due to possible side effects of high doses of these drugs. On the other hand, combined treatment of leukemia with statins and the conventional chemotherapeutics is questionable because of unknown influence of the first on the standard treatment results. This study has revealed thatin vitroatorvastatin increases the proapoptotic potential of cladribine and mafosfamide in CLL cells isolated from peripheral blood of patients. Moreover, a preincubation with the above statin sensitizes leukemic cells to CM-induced apoptosis even at small concentrations of the drug. The usage of atorvastatin together with or followed by the conventional chemotherapy should be considered as therapeutic option for the treatment for this leukemia. Interestingly, CM-resistant patients might have the biggest benefits from atorvastatin administration.

scholarly journals Interferon system in primary acute lymphocytic leukemia cells with or without deletions of the alpha-/beta-interferon genes

Blood ◽  
1992 ◽  
Vol 79 (8) ◽  
pp. 2076-2083 ◽  
Author(s):  
D Grander ◽  
M Heyman ◽  
K Brondum-Nielsen ◽  
Y Liu ◽  
E Lundgren ◽  
...  
Keyword(s):  
Acute Lymphocytic Leukemia ◽  
Lymphocytic Leukemia ◽  
Leukemic Cells ◽  
Malignant Cells ◽  
Oligoadenylate Synthetase ◽  
Gene Deletions ◽  
Functional Studies ◽  
Cell Clones ◽  
Alpha Beta

Abstract Various aspects of the interferon (IFN) system were studied in malignant cells from 37 unselected patients with acute lymphocytic leukemia (ALL). It was found that leukemic cells from two of 37 patients had a complete loss of alpha- and beta-IFN genes, whereas cells from four of 37 had lost one of the alpha-/beta-IFN alleles. In 25 cases, viable cells were also available for functional studies. Cell clones with loss of one of the alpha-/beta-IFN alleles produced low amounts of IFN after virus induction in vitro. Some clones with an apparently normal set of IFN genes were unable to produce detectable amounts of IFN. All clones studied were found to carry high-affinity alpha-IFN receptors. In clones carrying deletions of IFN genes, the cells were sensitive to IFN in vitro as measured by alpha-IFN-induced enhancement of 2′,5′-oligoadenylate synthetase (2′,5′-A synthetase). Cells from four patients with an apparently normal set of IFN genes were insensitive to this effect of IFN. We conclude that of the 17 patients in which IFN genes, IFN production, alpha-IFN receptors, and IFN-induced enhancement of 2′,5′-A synthetase were studied, nine (53%) showed some abnormality in their IFN system. This finding may add some support to the hypothesis that defects in the IFN system could be a step on the path to malignant transformation in ALL. Moreover, patients whose malignant cells carry IFN gene deletions or other defects in their IFN-producing capacity, but are still sensitive to exogenous IFN, could represent a subgroup of ALL with a greater likelihood of responding to IFN therapy.

scholarly journals Interleukin-5 (IL-5) increases spontaneous apoptosis of B-cell chronic lymphocytic leukemia cells in vitro independently of bcl-2 expression and is inhibited by IL-4

Blood ◽  
1994 ◽  
Vol 84 (7) ◽  
pp. 2297-2304 ◽  
Author(s):  
T Mainou-Fowler ◽  
VA Craig ◽  
JA Copplestone ◽  
MD Hamon ◽  
AG Prentice
Keyword(s):  
Lymphocytic Leukemia ◽  
Leukemia Cells ◽  
Percentage Increase ◽  
Spontaneous Apoptosis ◽  
Interleukin 5 ◽  
The Third ◽  
The Mean ◽  
Induced Apoptosis ◽  
Cell Chronic Lymphocytic Leukemia

Abstract During hematopoiesis, viability factors that suppress apoptosis are required throughout the differentiation process. Some of these factors may also function as growth factors. Interleukin-5 (IL-5) is recognized as a growth factor in hematopoiesis. We examined the involvement of IL- 5 as a viability factor of B-CLL in vitro. In 13 B-CLL cases studied, IL-5 at 20 U/mL increased spontaneous apoptosis by a mean percentage of 53% (range, 20% to 129%) (P < .05) after 2 days in culture. On the third day, the mean percentage increase was 37% (range, 18% to 50%). In all cases, IL-4 protected B-CLL cells against IL-5-induced apoptosis by a mean percentage of 47% (range, 18% to 81%) (P < .001). This protection was specific to IL-4 and it was reduced with anti-IL-4 antibody. In addition, expression of bcl-2 protein in untreated cultures was not significantly different from that of the IL-5-treated cells; mean equivalent of soluble fluorochrome (MESF) was 5.2 (range, 3.0 to 6.8) and 4.9 (range, 3.0 to 6.3), respectively (P > .2). In freshly isolated B-CLL cells, the MESF was 4.5 (range, 2.4 to 6.6). These results show that IL-5 induced apoptosis in B-CLL cells by a pathway that is independent of bcl-2 expression. IL-4 partially protects against this effect.

Aberrant expression of B-lymphocyte stimulator by B chronic lymphocytic leukemia cells: a mechanism for survival

Blood ◽  
2002 ◽  
Vol 100 (8) ◽  
pp. 2973-2979 ◽  
Author(s):  
Anne J. Novak ◽  
Richard J. Bram ◽  
Neil E. Kay ◽  
Diane F. Jelinek
Keyword(s):  
B Cells ◽  
Chronic Lymphocytic Leukemia ◽  
B Cell ◽  
B Lymphocyte ◽  
Leukemic Cell ◽  
Lymphocytic Leukemia ◽  
Leukemic Cells ◽  
Aberrant Expression ◽  
B Lymphocyte Stimulator

B-cell chronic lymphocytic leukemia (B-CLL) is defined by the accumulation of CD5+ B cells in the periphery and bone marrow. This disease is not characterized by highly proliferative cells but rather by the presence of leukemic cells with significant resistance to apoptosis and, therefore, prolonged survival. B-lymphocyte stimulator (BLyS) is a newly identified tumor necrosis factor (TNF) family member shown to be critical for maintenance of normal B-cell development and homeostasis and it shares significant homology with another TNF superfamily member, APRIL. The striking effects of BLyS on normal B-cell maintenance and survival raises the possibility that it may be involved in pathogenesis and maintenance of hematologic malignancies, including B-CLL. In this study, we investigated the status of APRIL and BLyS expression, as well as their receptors, in this disease. All B-CLL patient cells studied expressed one or more of 3 known receptors for BLyS; however, the pattern of expression was variable. In addition, we demonstrate for the first time that B-CLL cells from a subset of patients aberrantly express BLyS and APRIL mRNA, whereas these molecules were not detectable in normal B cells. Furthermore, we provide in vitro evidence that BLyS protects B-CLL cells from apoptosis and enhances cell survival. Because these molecules are key regulators of B-cell homeostasis and tumor progression, leukemic cell autocrine expression of BLyS and APRIL may be playing an important role in the pathogenesis of this disease.

scholarly journals Relevant Cytokines in the B Cell Lymphoma Micro-Environment

Cancers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2525
Author(s):  
Günter Krause ◽  
Floyd Hassenrück ◽  
Michael Hallek
Keyword(s):  
B Cell ◽  
Cytokine Production ◽  
Cell Lymphoma ◽  
B Cell Lymphoma ◽  
Cell Types ◽  
Cell Receptor ◽  
Lymphocytic Leukemia ◽  
Blood Levels ◽  
Stromal Fibroblasts

Cytokines are soluble protein factors with importance in intercellular communication and, as such, play pivotal roles in the pathogenesis of B cell malignancies. Evidence from in vitro cultures permitted us to choose example cytokines that bind to different biochemical receptor types. Activated malignant B cells or stromal fibroblasts and macrophages prominently secrete the chemokines CCL3 or CXCL12 and CXCL13, respectively. Apart from helper T cells, various cell types of the B cell lymphoma microenvironment are capable of producing the cytokines IL-4, IL-6, IL-10 and TNFα. Owing to its impact on the development of myeloid cells, CSF-1 is among important soluble factors in the B cell lymphoma microenvironment. Inhibitors of B cell receptor-associated kinases often act via the blockade of cytokine production, but also prevent cytokine effects, e.g., chemotaxis. Increments in blood levels in chronic lymphocytic leukemia patients compared to healthy donors and normalization upon treatment with ibrutinib can be explained by producing cell types and modulation of cytokine production observed in vitro.

Triggering of CD40 Antigen Inhibits Fludarabine-Induced Apoptosis in B Chronic Lymphocytic Leukemia Cells

Blood ◽  
1998 ◽  
Vol 92 (3) ◽  
pp. 990-995 ◽  
Author(s):  
Maria Fiammetta Romano ◽  
Annalisa Lamberti ◽  
Pierfrancesco Tassone ◽  
Fiorella Alfinito ◽  
Silvia Costantini ◽  
...  
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
Consensus Sequence ◽  
Significant Proportion ◽  
Lymphocytic Leukemia ◽  
Antiapoptotic Effect ◽  
Apoptotic Effect ◽  
American Society ◽  
Induced Apoptosis ◽  
Decoy Oligonucleotide

Abstract We analyzed the effect of CD40 triggering on the fludarabine-induced apoptosis of B chronic lymphocytic leukemia (B-CLL) cells. Peripheral blood samples obtained from 15 patients were incubated with fludarabine in the absence or the presence of the anti-CD40 monoclonal antibody (MoAb) G28-5. In 12 patients a significant proportion of apoptotic cells, ranging from 22% to 38% (mean ± SE: 28.5 ± 1.6), were detected after 3 days of culture. In 9 of these samples, the addition of G28-5 reduced apoptosis by at least 30.1% and by 57.1% ± 7.8% on average (P = .0077). Because the CD40 antigen activates NF-κB/Rel transcription factors in B cells, and NF-κB/Rel complexes can inhibit cell apoptosis, we investigated whether the antiapoptotic effect of G28-5, in our system, could be related to modulation of NF-κB/Rel activity. As expected, B-CLL cells displayed significant levels of nuclear NF-κB/Rel activity; p50, RelA, and c-Rel components of the NF-κB/Rel protein family were identified in these complexes. After exposure to fludarabine, NF-κB/Rel complexes were decreased in the nuclei. The addition of G28-5 upregulated the NF-κB/Rel levels. To determine the involvement of NF-κB/Rel activity in the G28-5–mediated inhibition of apoptosis, we blocked the transcription factor with a decoy oligonucleotide, corresponding to the NF-κB/Rel consensus sequence. Cells incubated with the anti-CD40 MoAb in the presence of the decoy oligonucleotide but not a control oligonucleotide displayed a complete impairment of the G28-5 antiapoptotic effect, indicating that NF-κB/Rel activity was required for the inhibition of apoptosis. These results suggest that CD40 triggering in vivo could counteract the apoptotic effect of fludarabine on B-CLL cells and that its neutralization, or the use of NF-κB/Rel inhibitors, could improve the therapeutic effect of fludarabine. © 1998 by The American Society of Hematology.

scholarly journals 3,3′-Diindolylmethane Promotes BDNF and Antioxidant Enzyme Formation via TrkB/Akt Pathway Activation for Neuroprotection against Oxidative Stress-Induced Apoptosis in Hippocampal Neuronal Cells

Antioxidants ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 3 ◽  
Author(s):  
Bo Dam Lee ◽  
Jae-Myung Yoo ◽  
Seong Yeon Baek ◽  
Fu Yi Li ◽  
Dai-Eun Sok ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Antioxidant Enzymes ◽  
Neurodegenerative Diseases ◽  
Antioxidant Enzyme ◽  
Neuronal Cells ◽  
Akt Pathway ◽  
Heme Oxygenase 1 ◽  
Enzyme Formation ◽  
Induced Apoptosis

3,3′-Diindolylmethane (DIM), a metabolite of indole-3-carbinol present in Brassicaceae vegetables, possesses various health-promoting effects. Nonetheless, the effect of DIM on neurodegenerative diseases has not been elucidated clearly. In this study, we hypothesized DIM may protect neuronal cells against oxidative stress-induced apoptosis by promoting the formation of brain-derived neurotrophic factor (BDNF) and antioxidant enzymes through stabilizing the activation of the tropomyosin-related kinase receptor B (TrkB) cascade and we investigated the effect of DIM on oxidative stress-mediated neurodegenerative models. DIM protected neuronal cells against oxidative stress-induced apoptosis by regulating the expression of apoptosis-related proteins in glutamate-treated HT-22 cells. Additionally, DIM improved the expression of BDNF and antioxidant enzymes, such as heme oxygenase-1, glutamate-cysteine ligase catalytic subunit, and NAD(P)H quinine oxidoreductase-1, by promoting the activation of the TrkB/protein kinase B (Akt) pathway in the cells. Consistent with in vitro studies, DIM attenuated memory impairment by protecting hippocampal neuronal cells against oxidative damage in scopolamine-treated mice. Conclusionally, DIM exerted neuroprotective and antioxidant actions through the activation of both BDNF production and antioxidant enzyme formation in accordance with the TrkB/Akt pathway in neuronal cells. Such an effect of DIM may provide information for the application of DIM in the prevention of and therapy for neurodegenerative diseases.

scholarly journals High incidence of monoclonal proteins in the serum and urine of chronic lymphocytic leukemia patients

Blood ◽  
1984 ◽  
Vol 64 (6) ◽  
pp. 1207-1211 ◽  
Author(s):  
MJ Deegan ◽  
JP Abraham ◽  
M Sawdyk ◽  
EJ Van Slyck
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
Lymphocytic Leukemia ◽  
Leukemic Cells ◽  
Membrane Immunoglobulin ◽  
High Incidence ◽  
Secretory Products ◽  
Monoclonal Proteins ◽  
Chain Type ◽  
Serum And Urine

Abstract Chronic lymphocytic leukemia (CLL) is generally considered a nonsecretory B cell immunoproliferative disorder. Conventional electrophoretic and immunoelectrophoretic methods have revealed serum monoclonal proteins in less than 10% of these patients. However, there is increasing experimental evidence from in vitro studies demonstrating that CLL cells may secrete immunoglobulins, particularly free light chains. We examined the serum and urine of 36 consecutive CLL patients for monoclonal proteins using sensitive immunochemical methods (high resolution agarose gel electrophoresis combined with immunofixation). The results obtained were correlated with the Rai stage, quantitative immunoglobulin levels, and lymphocyte membrane immunoglobulin phenotype of the leukemic cells. Twenty-three monoclonal proteins were identified in the serum or urine of 22 patients, an incidence of 61%. Six patients had serum monoclonal proteins, seven had only urinary monoclonal proteins, and nine had monoclonal proteins in serum and urine. In every instance the monoclonal protein was the same light chain type as expressed on the leukemic cells. Our findings suggest that the monoclonal proteins observed in the serum or urine of CLL patients are secretory products of the tumor cells and that their discovery is a function of the sensitivity of the method used for their detection.

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