Microenvironment-Induced Expression of PIM Kinases Supports Chronic Lymphocytic Leukemia Cells Survival and Promotes CXCR4-mTOR Pathway Dependent Migration

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 3239-3239 ◽  
Author(s):  
Emilia Bialopiotrowicz ◽  
Patryk Gorniak ◽  
Bartosz Pula ◽  
Monika Noyszewska-Kania ◽  
Hanna Makuch-Lasica ◽  
...  
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
Stromal Cells ◽  
Peripheral Blood ◽  
Surface Expression ◽  
Mtor Pathway ◽  
Lymphocytic Leukemia ◽  
Apoptotic Response ◽  
Pim Kinases

Abstract Lymph node microenvironment provides chronic lymphocytic leukemia (CLL) cells with pro-survival and protective signals, fostering resistance to conventional chemotherapeutics. CLL cells overexpress oncogenic PIM kinases, which modulate proteins engaged in transcription, translation, apoptosis, cell cycle and adhesion/motility (Mol Cancer Ther 2014, 13: 1231-45). Herein, we searched for the link between tumor microenvironment and PIMs expression, compared the clinical characteristics of CLL patients with high versus low expression of PIM kinases, and investigated the consequences of their inhibition with newly developed pan-PIM inhibitor, SEL24-B489 in primary CLL cells. We first evaluated the expression of PIM kinases in CD19+ cells derived from 88 newly diagnosed CLL cases. Patients with unmutated IGHV status exhibited significantly higher PIM1 transcript levels than patients with mutated IGHV genes. Subjects with advanced CLL (Binet C) exhibited higher PIM2 expression than patients in Binet A/B stage. Significantly higher PIM2 transcript abundance at the time of diagnosis was also observed in patients who relapsed after first line treatment (p=0.005). Expression of PIM2 and PIM3 kinases in lymph nodes was significantly higher than in peripheral blood, suggesting a relationship between PIM kinase expression/activity and CLL cell microenvironment. To further explore the role of microenvironment in the control of PIM expression, peripheral blood CLL cells were incubated with anti-IgM or CD40 ligand. Both stimuli induced PIM1 and PIM3 expression. Co-culture of CLL cells with stromal cell (HS5) monolayers promoted the expression of PIM3 isoform. We next assessed the consequences of PIM inhibition in CLL cells using novel pan-PIM inhibitor, SEL24-B489. Incubation with SEL24-B489 decreased phosphorylation of PIM substrates, p-FOXO1/3a(T24/T32) and p-4EBP1(S65), and induced dose-dependent apoptosis in 27 out of 28 analyzed cases, regardless of the IGHV mutation status and including relapsed patients. Of note, SEL24-B489 induced higher apoptotic response in primary CLL cells than referential pan-PIM inhibitor AZD1208. CLL cells with 17p13 deletion and obtained from chemo-refractory patients were also vulnerable to SEL24-B489, suggesting that functional p53 is not required for execution of SEL24-B489-mediated apoptosis. Importantly, SEL24-B489 was not toxic for cells derived from healthy donors. Since microenvironmental cues increase expression of PIM kinases, we hypothesized that interactions with stromal cells might hinder the in vitro activity of the PIM inhibitor. To explore this possibility, we compared apoptotic response to SEL24-B489 in CLL cells co-cultured on HS5 monolayers and CLL cells grown without the stromal support. In 6 out of 7 tested cases, SEL24-B489 overrode the protective signals from HS5 cells and induced apoptosis, although the cytotoxic effect of PIM inhibitor was stronger in the absence of stromal cells. PIM1 was shown to regulate CLL cells migration through CXCR4(S339) phosphorylation (Mol Cancer Ther 2014, 13: 1231-45). Accordingly, SEL24-B489 decreased phospho-CXCR4(S339), CXCR4 surface expression, and impaired CLL cells migration in the CXCL12 gradient. Surprisingly, decrease in the CXCR4 surface expression after SEL24-B489 was relatively modest when compared to the effect of this inhibitor on CXCL12-directed migration. We found that incubation of CLL cells with CXCL12 led to increase in the phosphorylation of mTOR(S2448) and Akt(S473). SEL24-B489 reduced the levels of p-mTOR(S2448), p-Akt(S473), p-4EBP1(T37/T46) and p-TSC2(S1798), revealing inhibitory effect on mTOR pathway. Pre-incubation of CLL cells with an mTOR inhibitor similarly restrained CXCL12-mediated mTOR activity and led to impaired CLL cells migration, uncovering the key role of mTOR axis in CXCR4-dependent migration. Thus, SEL24-B489 impairs the CLL cell migration by inhibiting CXCR4 surface expression and the CXCR4-triggered mTOR pathway. Taken together, we show that microenvironment signals increase expression of PIM kinases, supporting CLL cell survival and migration. Inhibition of PIM kinases impairs CXCR4-dependent migration and leads to CLL cells death, regardless of the p53 status. Targeting PIM kinases in CLL patients will likely release the cells from microenvironmental niches and might be a rational therapeutic strategy. Disclosures Warzocha: Novartis: Consultancy, Honoraria; BMS: Consultancy, Honoraria. Czardybon:Selvita S.A.: Employment. Galezowski:Selvita S.A.: Employment. Windak:Selvita S.A.: Employment. Brzozka:Selvita S.A.: Employment. Juszczynski:Selvita S.A.: Consultancy, Membership on an entity's Board of Directors or advisory committees.

Activity of PIM Kinases in Chronic Lymphocytic Leukemia Modulates Tumor Cell Survival and Stromal Interactions through a Pleiotropic Mechanism Involving Modulation of CXCR4 - mTOR Pathway

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 1549-1549
Author(s):  
Emilia Bialopiotrowicz ◽  
Patryk Gorniak ◽  
Maciej Szydlowski ◽  
Tomasz Sewastianik ◽  
Przemyslaw Kiliszek ◽  
...  
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
Stromal Cells ◽  
Clinical Characteristics ◽  
Surface Expression ◽  
Mtor Pathway ◽  
Lymphocytic Leukemia ◽  
Pim Kinases ◽  
And Migration ◽  
Kinase Expression ◽  
Mtor Activity

Abstract The survival of chronic lymphocytic leukemia (CLL) cells depends on their interactions with microenvironment components, such as stromal and T cells. Lymph node microenvironment provides protective signals that enable the formation of proliferation centers and favor resistance to conventional chemotherapeutics. One of the key molecules engaged in the communication of CLL cells with their microenvironment is C-X-C chemokine receptor type 4 (CXCR4). The surface expression of CXCR4 is regulated by PIM1 (provirus integration site for Moloney murine leukemia virus) kinase. PIM 1-3 kinases are overexpressed in CLL cells and recent data suggest that targeting PIMs might be a rational therapeutic approach in this type of leukemia. Herein, we assessed associations of PIM kinase expression with clinical characteristics of CLL patients and investigated the consequences of PIM kinase inhibition for cell survival and CXCR4 - dependent signal transduction and migration of primary CLL cells. In primary CLL cells from peripheral blood, PIM2 transcript abundance was higher than PIM1 and PIM3 (p<0.001). PIM2 expression was higher in patients with advanced disease (Rai 3-4, p=0.004). Higher PIM2 expression was also observed in patients who relapsed after first line treatment (p=0.005). Expression of PIM2 and PIM3 kinases in lymph nodes was significantly higher than in peripheral blood (p=0.024 and p=0.0059, respectively; Herishanu et al., 2010), suggesting a relationship between PIM kinase expression/activity and CLL cell microenvironment. To further explore the role of PIM kinases in these processes, we assessed whether PIM inhibition interferes with CXCR4 - mediated signaling and migration. We incubated primary CLL cells with a novel pan-PIM inhibitor SEL24-B489 and found decreased phospho-CXCR4 (Ser339) level and decreased CXCR4 surface expression. Primary CLL cells incubated with with SDF1 (500 ng/ml, 15-60 min) exhibited highly increased phosphorylations of mTOR (Ser2448) and Akt (Ser437). Since PIM kinases modulate mTOR signaling, we further investigated whether inhibition of PIM kinases with SEL24-B489 interferes with CXCR4/mTOR pathway. SEL24-B489 blocked baseline phosphorylation level of mTOR negative regulator p-TSC2 (Ser1798). Since TSC2 Ser1798 phosphorylation relieves its suppression on RHEB and promotes mTOR activity, we next assessed PIM inhibitor - induced changes in p-mTOR (Ser2448). Upon SEL24-B489 treatment, mTOR Ser2448 phosphorylation and activity of mTOR downstream substrates (p-Akt Ser473 and p-4EBP1 Thr37/46) markedly decreased. Pre-incubation of CLL cells with 10 uM SEL24-B489 or 10 uM mTOR inhibitor OSI-027 before SDF1 treatment restrained the increase of p-mTOR (Ser2448), p-Akt (Ser473), p-4EBP1 (Thr37/46) and p-TSC2 (Ser1798), and consequently impaired CLL cells migration in the SDF1 gradient. In 4 out of 7 analyzed patients the effect of SEL24-B489 on CLL migration was stronger than the effect of OSI-027 and in the remaining 3 patients, the effects of both inhibitors were similar. Since interactions of CLL cells with their microenvironment block the cytotoxicity of chemotherapeutic agents, we next compared the apoptotic response to SEL24-B489 in CLL cells cultured in the absence or presence of human bone marrow HS5 cells. CLL cells were seeded on HS5 monolayers and treated with SEL24-B489 (5 uM and 10 uM) for 48 hours. In 6 out of 7 cases SEL24-B489 overcame the protective signals from HS5 cells and induced apoptosis, although the cytotoxic effect of PIM inhibitor was stronger in the absence of stromal cells. Taken together, our data demonstrate that CXCR4/SDF1 signal in chronic lymphocytic leukemia cells is transduced through mTOR pathway and that CXCR4 - triggered mTOR activity is modulated by PIM kinases. Pan-PIM inhibitor SEL24-B489 decreased CXCR4 surface expression and SDF-1 - triggered mTOR activity. Finally, SEL24-B489 decreased protective effects of tumor microenvironment and induced CLL cells apoptosis even in the presence of stromal cells. Since overexpression of PIM kinases might be associated with adverse clinical characteristics at diagnosis, PIM inhibition might be a rational therapeutic strategy in CLL. Disclosures Czardybon: Selvita S.A.: Employment. Galezowski:Selvita S.A.: Employment. Windak:Selvita S.A.: Employment. Brzozka:Selvita S.A.: Employment. Juszczynski:Selvita S.A.: Other: member of Selvita Scientific Advisory Board.

scholarly journals Dissecting the Prognostic Significance and Functional Role of Progranulin in Chronic Lymphocytic Leukemia

Cancers ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 822 ◽  
Author(s):  
Lena Schulze-Edinghausen ◽  
Claudia Dürr ◽  
Selcen Öztürk ◽  
Manuela Zucknick ◽  
Axel Benner ◽  
...  
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
Stromal Cells ◽  
Prognostic Significance ◽  
Lymphocytic Leukemia ◽  
Cancer Associated Fibroblast ◽  
Survival Gene ◽  
Potential Use

Chronic lymphocytic leukemia (CLL) is known for its strong dependency on the tumor microenvironment. We found progranulin (GRN), a protein that has been linked to inflammation and cancer, to be upregulated in the serum of CLL patients compared to healthy controls, and increased GRN levels to be associated with an increased hazard for disease progression and death. This raised the question of whether GRN is a functional driver of CLL. We observed that recombinant GRN did not directly affect viability, activation, or proliferation of primary CLL cells in vitro. However, GRN secretion was induced in co-cultures of CLL cells with stromal cells that enhanced CLL cell survival. Gene expression profiling and protein analyses revealed that primary mesenchymal stromal cells (MSCs) in co-culture with CLL cells acquire a cancer-associated fibroblast-like phenotype. Despite its upregulation in the co-cultures, GRN treatment of MSCs did not mimic this effect. To test the relevance of GRN for CLL in vivo, we made use of the Eμ-TCL1 CLL mouse model. As we detected strong GRN expression in myeloid cells, we performed adoptive transfer of Eμ-TCL1 leukemia cells to bone marrow chimeric Grn−/− mice that lack GRN in hematopoietic cells. Thereby, we observed that CLL-like disease developed comparable in Grn−/− chimeras and respective control mice. In conclusion, serum GRN is found to be strongly upregulated in CLL, which indicates potential use as a prognostic marker, but there is no evidence that elevated GRN functionally drives the disease.

scholarly journals T cell chronic lymphocytic leukemia: presence in bone marrow and peripheral blood of cells that suppress erythropoiesis in vitro

Blood ◽  
1978 ◽  
Vol 52 (1) ◽  
pp. 255-260 ◽  
Author(s):  
R Hoffman ◽  
S Kopel ◽  
SD Hsu ◽  
N Dainiak ◽  
ED Zanjani
Keyword(s):  
Bone Marrow ◽  
T Cell ◽  
Chronic Lymphocytic Leukemia ◽  
T Lymphocytes ◽  
Peripheral Blood ◽  
Lymphocytic Leukemia ◽  
Transfusion Therapy ◽  
Cell Chronic Lymphocytic Leukemia ◽  
Marrow Cells

Abstract The pathogenesis of the anemia associated with malignancy was investigated in a patient with T cell chronic lymphocytic leukemia. The plasma clot culture system was used as a measure in vitro of erythropoiesis. The patient's peripheral blood and marrow T lymphocytes obtained both before and after transfusion therapy suppressed erythroid colony formation by normal human bone marrow cells. Pretreatment of the patient's bone marrow T cells by antithymocyte globulin (ATG) and complement reversed this suppression. In addition, pretreatment of the patient's marrow cells with ATG and complement markedly augmented erythropoiesis in vitro. The expression of erythroid activity caused by the selective destruction of the suppressor T lymphocytes in the patient's bone marrow with ATG and the suppression of normal erythropoiesis by the patient's bone marrow and peripheral blood lymphocytes suggest that interaction between the malignant T cell and the erythropoietin-responsive stem cell is important in production of anemia in this patient.

Sphingosine 1-Phosphate (S1P) Induces Migration and ERK/MAP-Kinase-Dependent Proliferation in Chronic Lymphocytic Leukemia (B-CLL) Due to Expression of the G Protein-Coupled Receptors S1P1/4.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 4996-4996
Author(s):  
Gabriele Seitz ◽  
Sedat Yildirim ◽  
Andreas M. Boehmler ◽  
Lothar Kanz ◽  
Robert Möhle
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
G Protein ◽  
Cell Lines ◽  
Peripheral Blood ◽  
G Protein Coupled Receptors ◽  
Lymphocytic Leukemia ◽  
S1p Receptors ◽  
Sphingosine 1 Phosphate ◽  
G Protein Coupled

Abstract Egress of lymphocytes from lymphoid organs into the circulation has been shown to depend on the presence of the lipid mediator sphingosine 1-phosphate (S1P) in the peripheral blood, and expression of corresponding S1P receptors (i.e., S1P1), that belong to the family of 7-transmembrane G protein-coupled receptors (GPCR). As circulating lymphocytic lymphoma cells are a hallmark of chronic lymphocytic leukemia, we analyzed expression of different S1P receptors and the effects of S1P on B-CLL cells. By qualitative and quantitative (TaqMan) RT-PCR, significant mRNA expression of S1P1 and S1P4 was found in CLL cell lines (EHEB, MEC-1) and in most samples (S1P1 in 88%, S1P4 in 100%) of primary CD19+ cells isolated from the peripheral blood of untreated B-CLL patients. mRNA of other S1P receptors (S1P2, S1P3, S1P5) was less consistently detected. Normal, nonmalignant B cells were strongly positive for S1P1, while other S1P receptors were weakly expressed or negative. S1P induced typical effects of chemotactic GPCR, such as actin polymerization (analyzed by flow cytometry) and chemotaxis (measured in a modified Boyden chamber assay) in CLL cell lines and primary B-CLL cells. After serum deprivation in vitro, S1P induced phosphorylation of ERK/MAP-kinase as analyzed by Western blot, demonstrating that S1P receptors expressed in CLL were able to activate signaling pathways of GPCR not only related to cell migration and chemotaxis, but also to cell proliferation. Of note, the S1P1 ligand FTY720, which induces receptor internalization after prolonged exposure and acts as an antagonist, resulted in apoptosis in CLL cell lines and primary CLL cells in vitro, as measured by MTT-test and staining with Annexin-FITC, respectively. We conclude that sphingosine 1-phosphate, which is present in the peripheral blood in considerable amounts, contributes to the trafficking of B-CLL cells expressing the GPCRs S1P1/4, and to their prolonged survival.

Standardizing Co-Culture Conditions Between Chronic Lymphocytic Leukemia Cells and Marrow Stromal Cells: Towards a Reliable and Reproducible System to Assess Cell Adhesion-Mediated Drug Resistance

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 3149-3149
Author(s):  
Antonina Kurtova ◽  
Maite P. Quiroga ◽  
William G. Wierda ◽  
Michael Keating ◽  
Jan A. Burger
Keyword(s):  
Bone Marrow ◽  
Drug Resistance ◽  
Cell Adhesion ◽  
Chronic Lymphocytic Leukemia ◽  
Stromal Cells ◽  
Lymphocytic Leukemia ◽  
Marrow Stromal Cells ◽  
Hpv E6 ◽  
Induced Apoptosis

Abstract Contact between chronic lymphocytic leukemia (CLL) cells and accessory stromal cells in tissue microenvironments is considered to play a major role in regulating CLL cell survival and disease progression. Stromal cells of various origins and species, and variable stromal-CLL cell ratios have been used in the past to study CLL-stromal cell interactions and to assess cell-adhesion mediated drug resistance (CAM-DR). Because of the heterogeneity of the currently used in vitro systems to study CLL-MSC interactions, and the importance of these co-culture systems for development and testing of novel agents, we tested a panel of murine and human MSC lines for their capacities to support CLL cell survival and CAM-DR, using various CLL-MSC ratios and fludarabine (F-ara-A) to induce CLL cell apoptosis. We tested four murine, non-transformed MSC lines derived from bone marrow: M210B4, KUM4, ST-2 and KUSA-H1. Also, we tested three human transformed cell lines: Stroma-NKtert, derived from bone marrow and immortalized by human telomerase reverse transcriptase (hTERT), UE6E7-T2 derived from bone marrow and transformed with human papilloma viruses (HPV) E6, E7 and hTERT, and UCB408E6E7Tert33 derived from umbilical cord blood and transformed with hTERT and HPV E6, E7. CLL cells were isolated from peripheral blood of untreated patients and each cell line was tested with at least three different patients according to the following protocol: viability of CLL was tested after 24, 48 and 72 hours by flow cytometry after staining with DiOC6 and propidium iodide. The following conditions were assayed on each of the MSC lines: CLL cells in suspension culture, CLL cells in suspension culture with 10 mM F-ara-A, CLL cells in co-culture with MSC, and CLL cells in co-culture with MSC and with 10 mM F-ara-A. Firstly, we performed titration experiments in order to identify the most appropriate ratio between stromal and CLL cells, using CLL-MSC ratios of 5:1, 10:1, 20:1, 50:1 and 100:1. We found a decline in MSC-derived CLL cell protection at the highest ratio of 100:1, suggesting that ratios of 50:1 or lower provide optimal conditions for in vitro assays. Results shown in Table 1 were assayed using a 20:1 ratio and represented relative viabilities when compared to untreated controls (mean±SEM). Regarding the protective effect of different MSC, we found that all MSC lines demonstrated remarkable protection of CLL cells from spontaneous and F-ara-A-induced apoptosis. We also found that stromal cells that had round shape morphology and easily formed confluent monolayer (M210B4, KUSA-H1, Stroma-NKTert) showed more prolonged protective effect in comparison to cell lines with more spindle shaped morphology (ST-2, KUM4, UE6E7-T2). The failure of UE6E7-T2 and UCB408E6E7Tert33 to demonstrate long-term protection of CLL cells could be related to their own sensitivity to F-ara-A. In this comparative study we demonstrated that both murine and human MSC provide substantial and comparable levels of protection from spontaneous and drug-induced apoptosis. CLL:MSC ratios of 50:1 or lower can be considered ideal for co-culture experiments. Further experiments have to be done to determine the levels of MSC-derived protection in a larger series of CLL samples and in different laboratories for validation. Collectively, in these co-culture assays we can study CLL-MSC interactions and CLL drugs under more standardized conditions that may allow us to evaluate the efficacy of new treatments that target the CLL microenvironment. Time points 24 hours 48 hours 72 hours +Flu + MSC + MSC +Flu +Flu + MSC + MSC +Flu +Flu +MSC + MSC +Flu M210B4 85.2±2.4 117.2±5.0 110.5±4.9 30.8±12.6 138.1±9.5 113.0±2.2 5.2±3.1 138.1±5.1 120.4±3.4 ST-2 93.6±3.0 99.9±2.6 103.1±0.5 51.6±9.4 111.9±2.6 89.8±8.7 13.9±6.3 112.6±5.7 87.0±16.4 KUM-4 93.6±3.0 106.4±1.8 104.2±1.9 51.6±9.4 112.4±2.6 100.8±2.8 13.9±6.3 111.8±6.7 88.5±11.4 KUSA-H1 79.4±7.4 125.1±3.7 118.2±2.0 33.9±10.9 136.0±3.6 107.2±7.0 11.3±6.1 133.6±5.4 84.9±7.6 Stroma-NKTert 79.3±7.0 118.6±7.0 111.0±7.0 30.5±9.5 130.7±9.5 115.6±8.0 7.1±4.3 133.0±11.5 122.7±9.0 UE6E7-T2 79.3±7.0 113.4±3.9 109.3±3.0 30.5±9.5 118.4±4.8 85.0±7.1 7.1±4.3 119.2±6.9 51.0±10.1 UCB408 E6E7Tert33 81.5±7.2 120.2±5.4 111.8±2.7 36.7±9.4 123.7±6.3 86.7±7.7 8.5±6.7 119.7±6.1 50.8±13.0 Table 1. Flu: fludarabine (10mM/ml), MSC: marrow stromal cells

The Toll-Like Receptor-Like Molecule CD180 and Soluble CD14 Transmit Survival Signals in B-Cell Chronic Lymphocytic Leukemia Cells Presumably by Acting As Co-Receptors,

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 3883-3883
Author(s):  
Martina Seiffert ◽  
Angela Schulz ◽  
Stephan Stilgenbauer ◽  
Peter Lichter
Keyword(s):  
Intracellular Signaling ◽  
Surface Expression ◽  
Lymphocytic Leukemia ◽  
Toll Like Receptor ◽  
Soluble Cd14 ◽  
Soluble Factors ◽  
Cell Chronic Lymphocytic Leukemia ◽  
Survival Signals

Abstract Abstract 3883 Survival and proliferation of B-cell chronic lymphocytic leukemia (CLL) cells strongly depend on external factors. When removed from their natural microenvironment CLL cells rapidly undergo spontaneous apoptosis in vitro unless cocultured with stromal cells or non-malignant leukocytes. Recently, we could show that monocytes effectively support long-term survival of CLL cells in vitro. Our results from cytokine antibody arrays and extensive transcriptome analyses of primary CLL cell cocultures suggested a functional role of several soluble factors as well as signaling pathways of innate immunity, like Toll-like receptor-, TREM1- and NRF2-mediated signaling. The most interesting soluble factors are currently quantified in serum samples of the german CLL8 study cohort of CLL patients by cytometric bead arrays. So far, our data show that two of these candidates, CCL2 and soluble CD14, are significantly increased in the serum of CLL patients. In vitro studies using recombinant soluble CD14 demonstrated that CLL cell survival was significantly increased in the presence of this factor. CD14 which is expressed in particular by monocytes and macrophages is an important mediator of innate immunity. Along with TLR-4, CD14 acts as a co-receptor for the detection of bacterial lipopolysaccharide (LPS). Alternatively, LPS can also bind to the toll-like receptor-like molecule CD180, which shows strong homology to TLR-4, but does not harbor an intracellular signaling domain. Since TLR-4 is not expressed in CLL cells, we investigated the potential role of CD180 in CD14-mediated cell survival. Flow cytometry analysis revealed an upregulation of CD180 surface expression in CLL cells under survival-inducing culture conditions. Stimulation of CD180 with a cross-linking antibody resulted in activation of CLL cells measured by increased cell size and upregulation of the activation marker CD86, and significantly increased survival rates of CLL cells. Both CD14- and CD180-mediated survival signals lead to an increase in NF-κB activity and up-regulation of its target gene BCL-2. Depletion of CD180 surface expression in CLL cells abolished the pro-survival effect of soluble CD14, suggesting that this factor mediates its signals via binding to CD180. In summary, our data demonstrate that both, soluble CD14 and the toll-like receptor-like molecule CD180 transmit pro-survival signals in CLL cells, most likely by acting as co-receptors. Currently, we characterize the intracellular signaling machinery which is involved in these processes. Disclosures: No relevant conflicts of interest to declare.

Increased CD39 Expression on CD4+ T-Lymphocytes Has Clinical and Prognostic Significance in Chronic Lymphocytic Leukemia,

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 3895-3895
Author(s):  
Yair Herishanu ◽  
Inbal Hazan-Hallevi ◽  
Sigi Kay ◽  
Varda Deutsch ◽  
Aaron Polliack ◽  
...  
Keyword(s):  
T Cells ◽  
Chronic Lymphocytic Leukemia ◽  
T Lymphocytes ◽  
Peripheral Blood ◽  
Conflicts Of Interest ◽  
Prognostic Significance ◽  
Lymphocytic Leukemia ◽  
Leukemic Cells ◽  
Anti Inflammatory

Abstract Abstract 3895 Chronic lymphocytic leukemia (CLL) cells depend on their microenvironment for proliferation and survival. Ectonucleotidase CD39 has anti-inflammatory properties as it hydrolyzes pro-inflammatory extra-cellular ATP, generates anti-inflammatory adenosine and also protects regulatory T cells from ATP-induced cell death. In this study we investigated the clinical significance of CD39 expression on CD4+T-cells in 45 patients with CLL as well as its compartmental regulation and explored the possible mechanisms for its induction. Compared to healthy individuals, CD4+CD39+ lymphocytes were increased in the peripheral blood of patients with CLL (4.6%±2.28 vs. 17.3%±12.49, respectively, p=0.004), and correlated with advanced stage of disease (9.72%±5.76, 18.15%±12.03 and 25.90%±16.34, of CD4+ lymphocytes, in patients with Rai stages 0, 1+2 and 3+4, respectively, p=0.019). CD4+CD39+ cells were also higher in patients with CLL who needed therapeutic intervention (untreated; 12.99%±10.63 vs treated; 22.21%±12.88, p=0.01) and in those who were ZAP70+ or had b2-microglobulin levels>3g/L. There were more CD4+CD39+ lymphocytes in the bone marrow compartment (22.25%±16.16) than in the peripheral blood (16.60%±15.84, p=0.009). In-vitro studies showed that CD39 can be induced on CD4+cells by exposure to ATP or indirectly, following B-cell receptor (BCR) engagement (CD4+CD39+ lymphocytes increased by 1.56 fold, in the BCR engaged samples compared to their paired controls; 20.27%±11.3 vs. 13%±9.42, respectively, p=0.0006). Conclusions: Increased CD39 expression on CD4+ T-lymphocytes in CLL associates with an aggressive disease. This may reflect the ability of the leukemic cells to suppress the surrounding immune environment, and contribute to a poorer prognosis. CD39+ may also serve as a future target for the development of novel therapies with immune modulating anti–tumor agents in CLL. Disclosures: No relevant conflicts of interest to declare.

Mode of Action of the SDF-1/CXCL12 Inhibiting Spiegelmer® Nox-A12 and Its Impact On Chronic Lymphocytic Leukemia (CLL) Cell Motility and Chemosensitization

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 318-318
Author(s):  
Dirk Zboralski ◽  
Julia Hoellenriegel ◽  
Christian Maasch ◽  
Anna Kruschinski ◽  
Jan A. Burger
Keyword(s):  
Bone Marrow ◽  
Chronic Lymphocytic Leukemia ◽  
Stromal Cells ◽  
Mode Of Action ◽  
Leukemia Cell ◽  
Lymphocytic Leukemia ◽  
Lymphoid Tissues ◽  
Cell Trafficking ◽  
Dependent Manner

Abstract Abstract 318 NOX-A12 is a novel Spiegelmer®-based antagonist of SDF-1/CXCL12, a chemokine involved in the regulation of chronic lymphocytic leukemia (CLL) cell trafficking. Spiegelmers® are mirror-image oligonucleotides that are identified to specifically bind to proteins in a manner conceptually similar to antibodies. Unlike aptamers, however, Spiegelmers® are built from the non-natural L-isomer form of nucleotides which confers resistance to the action of nucleases and avoids potential immunogenicity. CXCL12 is constitutively secreted and presented by bone marrow stromal cells (BMSC) via glycosaminoglycans (GAG) and acts as a homing factor for normal and malignant hematopoietic cells to the bone marrow (BM) and secondary lymphoid tissues via CXCR4 receptors that are expressed at high levels on circulating CLL cells. The microenvironment in the BM and secondary lymphoid tissues, in particular the CXCL12-CXCR4 axis, favors survival and chemotherapy-resistance of leukemic cells. We therefore investigated the effects of NOX-A12 in an in vitro co-culture system to model the interaction of CLL cells with their microenvironment. Surprisingly we observed that NOX-A12 increased pseudoemperipolesis in vitro, i.e. spontaneous leukemia cell migration beneath BMSC. Interestingly, this NOX-A12 induced trans-migration of CLL cells was completely inhibited by the CXCR4 antagonist AMD3100, suggesting a CXCL12/CXCR4 dependent mechanism. We postulated that this observation might result from a direct effect of NOX-A12 on CXCL12 release by the stromal cells. Therefore, we investigated this hypothesis in different BMSC lines (MS-5, R15C, and TSt-4) and we found that NOX-A12 induced a significant CXCL12 release in all three tested cell lines. We asked whether this NOX-A12 dependent increase of CXCL12 of BMSCs is due to release from either intracellular or extracellular storages. Intracellular staining of CXCL12 using flow cytometry did not reveal significant changes when BMSCs were incubated with NOX-A12. Furthermore, the transcription of CXCL12 was not found to be altered after NOX-A12 incubation over a period of three days as shown by quantitative RT-PCR. Rather, CXCL12 is released from extracellular storages of BMSCs. First hints were obtained through a rapid CXCL12 release within five minutes of incubation with NOX-A12. To confirm that CXCL12 is bound to the extracellular surface (by GAGs like heparin) and is being detached by NOX-A12 we first incubated BMSCs with NOX-A12, followed by a wash step and the addition of recombinant CXCL12. Recombinant CXCL12 was bound by BMSCs that were pre-incubated with NOX-A12 but not with a non-functional control (revNOX-A12), indicating that NOX-A12 strips off CXCL12. To corroborate the findings we incubated the BMSCs with heparin which also led to the release of CXCL12 in a dose dependent manner. Of note, the EC50 of heparin regarding CXCL12 release was much higher compared to the EC50 of NOX-A12 (≈ 12 μM vs. 5 nM) revealing the high affinity of NOX-A12 to CXCL12. The competition of NOX-A12 with heparin regarding CXCL12 binding was confirmed by Biacore experiments. Based on these findings, we developed a novel adapted co-culture approach to examine the ability of NOX-A12 to chemosensitize CLL cells. In this setting, we first strip off CXCL12 from BMSCs by NOX-A12 and subsequently add CLL cells which will be either non-treated or treated with chemotherapy (fludarabine combined with bendamustine). We found that NOX-A12 slightly decreased CLL cell viability. As expected, a strong viability decrease was observed with chemotherapy, which could be even further decreased by the combination with NOX-A12, suggesting synergistic effects. In conclusion, we propose that NOX-A12's mode of action is the release of extracellular bound CXCL12 and its subsequent inhibition. Since CXCL12 induces leukemia cell trafficking and homing to tissue microenvironment and also favors leukemia cell survival, we believe that targeting CXCL12 is an attractive approach to remove the protective effects of CXCL12-secreting BMSCs in order to sensitize CLL cells for subsequent chemotherapy. Thus, NOX-A12 represents a very promising agent to significantly improve the treatment of CLL. The compound is currently being tested in a Phase IIa study in relapsed CLL patients. Disclosures: Zboralski: NOXXON Pharma AG, Berlin, Germany: Employment. Maasch:NOXXON Pharma AG: Employment. Kruschinski:NOXXON Pharma AG: Employment. Burger:NOXXON Pharma AG: Consultancy, Research Funding.

Concurrent up-regulation of BCL-XL and BCL2A1 induces approximately 1000-fold resistance to ABT-737 in chronic lymphocytic leukemia

Blood ◽  
2009 ◽  
Vol 113 (18) ◽  
pp. 4403-4413 ◽  
Author(s):  
Meike Vogler ◽  
Michael Butterworth ◽  
Aneela Majid ◽  
Renata J. Walewska ◽  
Xiao-Ming Sun ◽  
...  
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
Lymph Nodes ◽  
Peripheral Blood ◽  
De Novo ◽  
Phase 1 ◽  
Lymphocytic Leukemia ◽  
Interleukin 4 ◽  
Synergistic Activity

Abstract ABT-737 and its orally active analog, ABT-263, are rationally designed inhibitors of BCL2 and BCL-XL. ABT-263 shows promising activity in early phase 1 clinical trials in B-cell malignancies, particularly chronic lymphocytic leukemia (CLL). In vitro, peripheral blood CLL cells are extremely sensitive to ABT-737 (EC50 ∼7 nM), with rapid induction of apoptosis in all 60 patients tested, independent of parameters associated with disease progression and chemotherapy resistance. In contrast to data from cell lines, ABT-737–induced apoptosis in CLL cells was largely MCL1-independent. Because CLL cells within lymph nodes are more resistant to apoptosis than those in peripheral blood, CLL cells were cultured on CD154-expressing fibroblasts in the presence of interleukin-4 (IL-4) to mimic the lymph node microenvironment. CLL cells thus cultured developed an approximately 1000-fold resistance to ABT-737 within 24 hours. Investigations of the underlying mechanism revealed that this resistance occurred upstream of mitochondrial perturbation and involved de novo synthesis of the antiapoptotic proteins BCL-XL and BCL2A1, which were responsible for resistance to low and high ABT-737 concentrations, respectively. Our data indicate that after therapy with ABT-737–related inhibitors, resistant CLL cells might develop in lymph nodes in vivo and that treatment strategies targeting multiple BCL2 antiapoptotic members simultaneously may have synergistic activity.

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