scholarly journals Adhesion of ZAP-70+ chronic lymphocytic leukemia cells to stromal cells is enhanced by cytokines and blocked by inhibitors of the PI3-kinase pathway

2014 ◽  
Vol 38 (1) ◽  
pp. 109-115 ◽  
Author(s):  
Sandrine T. Lafarge ◽  
James B. Johnston ◽  
Spencer B. Gibson ◽  
Aaron J. Marshall
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
Stromal Cells ◽  
Pi3 Kinase ◽  
Lymphocytic Leukemia ◽  
Leukemia Cells ◽  
Pi3 Kinase Pathway ◽  
Kinase Pathway

Erythroid Differentiation Regulator 1 (ERDR1) From Nurse-Like Cells Promotes the Survival of Chronic Lymphocytic Leukemia Cells

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 1372-1372
Author(s):  
Hendrik W. Van Deventer ◽  
Robert Mango ◽  
Jonathan Serody
Keyword(s):  
Bone Marrow ◽  
Chronic Lymphocytic Leukemia ◽  
Stromal Cells ◽  
Stromal Cell ◽  
Conflicts Of Interest ◽  
Erythroid Differentiation ◽  
Mesenchymal Cells ◽  
Lymphocytic Leukemia ◽  
Leukemia Cells ◽  
Wild Type

Abstract Abstract 1372 Background: Chemotherapy resistance in chronic lymphocytic leukemia (CLL) can be mediated by anti-apoptotic signals produced by stromal or nurse-like cells. Developing strategies to overcome this resistance is hindered by the lack of suitable “stromal” targets responsible for these signals. We have discovered that erythroid differentiation regulator 1 (ERDR1) may be a candidate target for such a strategy. In this study, we show Erdr1 is generated by several stromal cell types including bone marrow stromal cells, fibrocytes, and nurse-like cells. Furthermore, inhibition of stroma-generated Erdr1 results in increased apoptosis of co-cultured CLL cells. Methods/Results: We initially identified Erdr1 on an Affymetrix array that compared the gene expression of wild type and CCR5-/- mice with pulmonary metastasis. The increased expression of Erdr1 in the wild type mice was particularly pronounced in the pulmonary mesenchymal cells. Therefore, these cells were transfected with one of two shRNAs (shRNA #9 or shRNA#11) and the survival of these cells was compared with mesenchymal cells transfected with a non-targeted control vector. After 15 days in culture, the control cells expanded normally; however, no significant expansion was seen in either the shRNA#9 or shRNA#11 transfected cells. These differences in cellular expansion were associated with differences in apoptosis. 21.4+1.6% of the Erdr1 knockdown cells were annexin V+ compared to 11.2+1.9% of the non-targeted control (p<0.03). Using GFP as a marker for transfection, we were also able to show that knockdown of Erdr1 increased the apoptosis of surrounding non-transfected mesenchymal cells. Thus, Erdr1 is a critical protein for the survival of stromal cells. Further analysis of the mesenchymal cell subpopulations revealed the greatest expression of Erdr1 in the CD45+, thy1.1+/− fibrocytes. When compared to CD45- fibroblasts, the fibrocytes expressed CCR5 and increased Erdr1 expression by 14.2+/−2.9 fold when treated with the CCR5 ligand CCL4. Given the similarities between fibrocytes and nurse-like cells, we went on to measure the effect of Erdr1 inhibition on CLL cells. In these experiments, stable Erdr1 knockdown and control clones were selected after the transfection of the bone marrow stromal cell line M2-10B4. These clones were then co-cultured with primary CLL cells. At 96 hours, leukemia cells co-cultured with the control lines had expanded by 1.33 + 0.9 compared to 0.74 + 0.22 fold in the knock-down lines (p<0.03). As before, the lack of cellular expansion was associated with an increase in apoptosis. To further show the relevance of these findings to CLL, we demonstrated that human fibrocytes and nurse-like cells expressed mRNA and protein for ERDR1 in all patient samples tested. Implications for the treatment of human disease: Our data demonstrate that ERDR1 is a critically important protein for the survival of nurse-like cells. These data suggest that targeting ERDR1 or the upstream pathway through CCR5 might be a novel approach for the treatment of CLL. Disclosures: No relevant conflicts of interest to declare.

BMS-936564 (MDX1338): A Fully Human Anti-CXCR4 Antibody Induces Apoptosis in an in Vitro Model of Stromal – Leukemia Cell Interaction for Chronic Lymphocytic Leukemia.

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 2887-2887
Author(s):  
Manoj Kumar Kashyap ◽  
Deepak Kumar ◽  
Harrison Jones Jones ◽  
Michael Y. Choi ◽  
Johanna Melo-Cardenas ◽  
...  
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
Stromal Cells ◽  
Leukemia Cell ◽  
Cell Interaction ◽  
Lymphocytic Leukemia ◽  
Leukemia Cells ◽  
Drug Induced ◽  
Induced Apoptosis ◽  
Cells Cultured

Abstract Abstract 2887 Chronic lymphocytic leukemia (CLL) remains incurable despite advances in the biology and treatment of this disease. Current data support the notion that resistance to therapy is promoted by a “protective” tumor microenvironment in which non-leukemia cells produce factors that enhance the resistance of CLL cells to spontaneous or drug-induced apoptosis. One such factor is the chemokine CXCL12, which interacts with its receptor CXCR4 on CLL cells to promote cancer cell survival. To examine the therapeutic potential of blocking CXCL12-CXCR4 interactions, we studied the effect of BMS-936564, a fully human IgG4 anti-CXCR4 antibody, using an in vitro co-culture model of human bone marrow derived stomal-NKter cells – leukemia cell interaction. Such stromal-NKter cells secrete CXCL12 and enhance the resistance of CLL cells to apoptosis in vitro. We observed that primary CLL cells co-cultured with stromal-NKter cells had significantly greater viability than CLL cells cultured alone (20–60% above baseline at 48 hours). Moreover, CLL cells co-cultured with stromal cells had enhanced resistance to drug-induced apoptosis. We found that BMS-936564 antibody at concentrations of 2–200nM could enhance the rate of apoptosis of CLL cells cultured alone or in the presence of stromal cells. CLL cells that expressed unmutated IgVH genes or ZAP-70 appeared equally susceptible to treatment with BMS-936564 as did CLL cells that lack these adverse prognostic markers, as did CLL cells that harbored deletions in 17p13.2 and that were resistant to chemotherapeutic agents, such a fludarabine monophosphate. BMS-936564 antibody inhibited CXCL12 mediated F-Actin polymerization in CLL cells at lower concentrations (20–200nM) compared to AMD-3100 (Mozobil), a small molecule CXCR4 inhibitor (50–150μM). In addition, AMD-3100 did not induce apoptosis in CLL cells (10–300μM). In summary, we observed that the anti-CXCR4 antibody BMS-936564 inhibited CXCL12 mediated activation of the CXCR4 receptor in CLL cells and induced apoptosis in leukemia cells. The pro-apoptotic activity of BMS-936564 was observed in cells cultured alone or together with stromal cells suggesting that this antibody had direct cytotoxic effect on leukemia cells and that it can overcome the protective tumor microenvironment. More over, the activity of BMS-936564 was independent of the presence of poor prognostic factors such as del(17p) suggesting that its mechanism of action is P53 independent. These findings show evidence that the CXCR4-CXCL12 pathway is a valid therapeutic target in CLL and provide additional biological rationale for ongoing clinical trials in CLL and other hematological malignancies using BMS-936564. Disclosures: Kuhne: Bristol-Myers Squibb: Employment. Sabbatini:Bristol-Myers Squibb: Employment. Cohen:Bristol-Myers Squibb: Employment. Shelat:Bristol-Myers Squibb: Employment. Cardarelli:Bristol-Myers Squibb: Employment. Kipps:Abbott: Consultancy, Research Funding.

scholarly journals Thioredoxin, produced by stromal cells retrieved from the lymph node microenvironment, rescues chronic lymphocytic leukemia cells from apoptosis in vitro

Haematologica ◽  
2007 ◽  
Vol 92 (11) ◽  
pp. 1495-1504 ◽  
Author(s):  
E. Backman ◽  
A.-C. Bergh ◽  
I. Lagerdahl ◽  
B. Rydberg ◽  
C. Sundstrom ◽  
...  
Keyword(s):  
Lymph Node ◽  
Chronic Lymphocytic Leukemia ◽  
Stromal Cells ◽  
Lymphocytic Leukemia ◽  
Leukemia Cells

scholarly journals The PI3-Kinase Delta Inhibitor Idelalisib (GS-1101) Targets Integrin-Mediated Adhesion of Chronic Lymphocytic Leukemia (CLL) Cell to Endothelial and Marrow Stromal Cells

PLoS ONE ◽  
2013 ◽  
Vol 8 (12) ◽  
pp. e83830 ◽  
Author(s):  
Stefania Fiorcari ◽  
Wells S. Brown ◽  
Bradley W. McIntyre ◽  
Zeev Estrov ◽  
Rossana Maffei ◽  
...  
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
Stromal Cells ◽  
Pi3 Kinase ◽  
Lymphocytic Leukemia ◽  
Marrow Stromal Cells

scholarly journals Venetoclax Is Synergistic with Idelalisib or MK2206 Against Primary CLL Cells in an in Vitro Model of the Microenvironment

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 5443-5443
Author(s):  
Yandong Shen ◽  
Kyle R Crassini ◽  
Narjis Fatima ◽  
Richard Christopherson ◽  
Stephen P. Mulligan ◽  
...  
Keyword(s):  
Clinical Trials ◽  
High Risk ◽  
Signaling Pathway ◽  
Conflicts Of Interest ◽  
Single Agent ◽  
Pi3 Kinase ◽  
Lymphocytic Leukemia ◽  
Pi3 Kinase Pathway ◽  
Kinase Pathway

Background The PI3-kinase signaling pathway and the Bcl-2-family of proteins play crucial roles in regulating the survival and proliferation of chronic lymphocytic leukemia (CLL) cells in the bone marrow and lymph nodes. Trials of ibrutinib, idelalisib and venetoclax illustrate the potential of targeting the B-cell receptor (BCR) signaling pathway and Bcl-2, however disease relapse is still common. Several pre-clinical studies and on-going clinical trials [Rogers et al., 2018, Jain et al., 2019] suggest that combinations of BCR inhibitors with venetoclax may be an effective treatment strategy for CLL patients with high risk disease. We sought to investigate the effects of combining idelalisib or the AKT inhibitor MK2206 with venetoclax against CLL cells under in vitro conditions that mimic the tumor microenvironment. Methods Primary CLL cells were co-cultured with CD40L-expressing mouse L-fibroblasts. Cell viability was assessed using the mitochondrial membrane potential dye DilC1(5), propidium iodide and flow cytometry (n = 6). Synergy between idelalisib or MK2206 and venetoclax was evaluated by calculating combination indices (CI) using the Compusyn software. The mechanisms of action of the drugs and synergies between the drugs were investigated by immunoblotting (n = 6). Results Venetoclax was highly synergistic in combination with idelalisib or MK2206 against CLL cells co-cultured with CD40L-fibroblasts, with CI values of 0.2 and 0.5 at a fractional effect of 0.9, respectively (Figure 1). This synergy was consistent with a significant (P < 0.05) reduction in the IC50 for venetoclax, idelalisib and MK2206. Immunoblotting suggests that MK2206, as a single agent or in combination with venetoclax, was more effective than idelalisib in inhibiting the phosphorylation of AKT and NF-κB. Both MK2206 and idelalisib as single agents and in combination with venetoclax significantly reduced expression of Mcl-1 and Bfl-1, two pro-survival members of the Bcl-2 family of proteins in primary CLL cells co-cultured with CD40L-fibroblasts. Conclusions The synergy observed, which was associated with a significant decrease in the IC50s for idelalisib and MK2206, may mitigate some of the toxicities associated with PI3-kinase pathway inhibitors. Comparison of the two PI3-kinase-pathway inhibitors suggests that MK2206 may be more effective than idelalisib at blocking BCR-mediated signaling as a single agent and in combination with venetoclax. The mechanisms underlying the synergy include down-regulation of expression of Bcl-2 family proteins that are not targeted by venetoclax as a single agent. The data presented support the rationale for on-going and future clinical trials of combination therapies incorporating a PI3-kinase inhibitor with venetoclax for the treatment of high risk CLL. Figure 1 Disclosures No relevant conflicts of interest to declare.

scholarly journals Proteomics profiling identifies induction of caveolin-1 in chronic lymphocytic leukemia cells by bone marrow stromal cells

2017 ◽  
Vol 59 (6) ◽  
pp. 1427-1438 ◽  
Author(s):  
Hima V. Vangapandu ◽  
Huiqin Chen ◽  
William G. Wierda ◽  
Michael J. Keating ◽  
Anil Korkut ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Chronic Lymphocytic Leukemia ◽  
Stromal Cells ◽  
Bone Marrow Stromal Cells ◽  
Lymphocytic Leukemia ◽  
Marrow Stromal Cells ◽  
Leukemia Cells ◽  
Caveolin 1

Targeting the CXCR4-CXCL12 Pathway Using an Anti-CXCR4 IgG1 Antibody (PF-06747143) in Chronic Lymphocytic Leukemia

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 4162-4162
Author(s):  
Manoj K. Kashyap ◽  
Carlos I. Amaya-Chanaga ◽  
Deepak Kumar ◽  
Michael Y. Choi ◽  
Laura Z. Rassenti ◽  
...  
Keyword(s):  
Cell Death ◽  
Tumor Microenvironment ◽  
Chronic Lymphocytic Leukemia ◽  
Stromal Cells ◽  
Advisory Board ◽  
Lymphocytic Leukemia ◽  
Leukemia Cells ◽  
Induce Cell Death ◽  
Igg1 Antibody ◽  
Cells Cultured

Abstract Chronic lymphocytic leukemia (CLL) is the most common type of leukemia in adults in the Western world. This leukemia is not curable and resistance to therapy is promoted by factors present in the tumor microenvironment including the chemokine CXCL12 (SDF-1), which interacts with its receptor CXCR4 and is thought to promote cancer cell survival. Here we explored the therapeutic potential of blocking CXCL12-CXCR4 interactions using PF-06747143, a humanized IgG1 antibody specific for CXCR4, which is expressed at high levels by CLL cells. Using primary leukemia cells from CLL patients, we found that PF-06747143 inhibited CXCL12-induced cell migration and blocked cytoskeletal changes via F-actin polymerization similar to AMD-3100 (Mozobil, a small molecule inhibitor of CXCR4). In addition, PF-06747143 induced apoptosis on CLL cells cultured alone or in the presence of human bone marrow-derived stromal cells (stroma-NK-tert). The pro-apoptotic activity of PF-06747143 was independent of high-risk prognostic factors including IGHV mutation status, ZAP-70 expression or TP53 mutation / 17p-deletion. Interestingly, AMD-3100, which binds and inhibits signaling through CXCR4, did not induce cell death in CLL or any of the cell lines tested. PF-06747143 did not induce apoptosis on normal B and T cells, and the ability of this anti-CXCR4 antibody to induce cell death on CLL cells appeared to be dependent on the crosslinking of CXCR4. This was supported by the fact that a Fab only fragment derived from PF-06747143 did not induce apoptosis despite of its high binding affinity for CXCR4. We observed that PF-06747143 induced complement-dependent cytotoxicity (CDC) and antibody-dependent cellular cytotoxicity (ADCC) in CLL cells. However, this antibody did not induce caspase activation but rather its cell death activity appeared to be dependent on the production of reactive oxygen species (ROS) in leukemia cells. This effect was similar to that observed with other ROS dependent antibodies such as obinutuzumab (Gazyva). ROS induction was observed with PF-06747143, but not its Fab derived fragment and preceded apoptosis suggesting that this is critical component of its mechanism of action. We evaluated synergism of PF-06747143 with other CLL therapeutic agents and observed that this antibody synergized with fludarabine, bendamustine, ibrutinib and rituximab in the majority of CLL patient samples tested. In summary, our studies showed that PF-06747143, a CXCR4 IgG1 antibody is a potent inhibitor of the CXCR4-CXCL12 pathway and induces cell death primarily in CLL cells but not in normal lymphocytes. The cytotoxic effect of PF-06747143 was similar in CLL cells cultured alone or with stromal cells, suggesting that this antibody has the potential to overcome the protective effect of the tumor microenvironment. We also showed that PF-06747143 induced programmed cell death on CLL cells was dependent on ROS production and that this antibody synergized with agents currently used for the treatment of CLL patients. Overall, these findings highlight the biological relevance of the CXCR4-CXCL12 pathway in CLL, and provide rationale for clinical evaluation of PF-06747143 in CLL and other cancers. Disclosures Choi: Gilead: Consultancy, Other: Advisory Board, Speakers Bureau; AbbVie: Consultancy, Other: Advisory Board, Research Funding. Kipps:Pharmacyclics Abbvie Celgene Genentech Astra Zeneca Gilead Sciences: Other: Advisor.

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