Chronic lymphocytic leukemia of Eμ-TCL1 transgenic mice undergoes rapid cell turnover that can be offset by extrinsic CD257 to accelerate disease progression

Blood ◽  
2009 ◽  
Vol 114 (20) ◽  
pp. 4469-4476 ◽  
Author(s):  
Thomas Enzler ◽  
Arnon P. Kater ◽  
Weizhou Zhang ◽  
George F. Widhopf ◽  
Han-Yu Chuang ◽  
...  
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
Disease Progression ◽  
Leukemia Cell ◽  
Lymphocytic Leukemia ◽  
Leukemia Cells ◽  
Cell Turnover ◽  
Proliferating Cells ◽  
Rapid Reduction ◽  
Disease Evolution ◽  
Dying Cells

AbstractResults of heavy-water labeling studies have challenged the notion that chronic lymphocytic leukemia (CLL) represents an accumulation of noncycling B cells. We examined leukemia cell turnover in Eμ-TCL1 transgenic (TCL1-Tg) mice, which develop a CLL-like disease at 8 to 12 months of age. We found that leukemia cells in these mice not only had higher proportions of proliferating cells but also apoptotic cells than did nonleukemic lymphocytes. We crossed TCL1-Tg with BAFF-Tg mice, which express high levels of CD257. TCL1×BAFF-Tg mice developed CLL-like disease at a significantly younger age and had more rapid disease progression and shorter survival than TCL1-Tg mice. Leukemia cells of TCL1×BAFF-Tg mice had similar proportions of proliferating cells, but fewer proportions of dying cells, than did the CLL cells of TCL1-Tg mice. Moreover, leukemia cells from either TCL1×BAFF-Tg or TCL1-Tg mice produced more aggressive disease when transferred into BAFF-Tg mice than into wild-type (WT) mice. Neutralization of CD257 resulted in rapid reduction in circulating leukemia cells. These results indicate that the leukemia cells of TCL1-Tg mice undergo high levels of spontaneous apoptosis that is offset by relatively high rates of leukemia cell proliferation, which might allow for acquisition of mutations that contribute to disease evolution.

A Phase II, Open Label Study of AT-101 in Combination with Rituximab in Patients with Relapsed or Refractory Chronic Lymphocytic Leukemia.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 2838-2838 ◽  
Author(s):  
Januario E. Castro ◽  
Loria J. Olivier ◽  
Aguillon A. Robier ◽  
James Danelle ◽  
Suarez J. Carlos ◽  
...  
Keyword(s):  
High Risk ◽  
Chronic Lymphocytic Leukemia ◽  
Adverse Events ◽  
Plasma Concentrations ◽  
Leukemia Cell ◽  
Lymphocytic Leukemia ◽  
Leukemia Cells ◽  
Pharmacokinetic Studies ◽  
Cell Counts ◽  
Grade 3

Abstract Chronic lymphocytic leukemia (CLL) cells express high-levels of Bcl-2 and related anti-apoptotic proteins that collectively can enhance leukemia-cell survival and drug-resistance. AT-101 is an orally active BH3-mimetic that can inhibit the anti-apoptotic activity of Bcl-2-family-member proteins (e.g. Bcl-2, Bcl-XL, Mcl-1) and induce CLL cells to undergo apoptosis. Furthermore, we found that AT-101 also can enhance the cytotoxicity of rituximab for CLL cells in vitro. As such we conducted a phase 2 trial to evaluate the safety and activity of AT-101 when used together with rituximab to treat 12 patients who had relapsed/refractory CLL. Patients received AT-101, at 30 mg/d, for 21 or 28 days during each of three 28-day cycles. Rituximab was administered at 375 mg/m2 for 12 doses (total dose = 4,500 mg/m2) on days 1, 3, 5, 8, 15, 22, 29, 31, 33, 40, 57, 59, 61. The first dose of rituximab was given over two days to minimize infusion-related adverse events. The patients’ median age was 61.5 years (range 43–81). Nine patients were high risk and 3 were intermediate risk based on the modified Rai classification and had received a median of 2 prior regimens (range 1–8). Six patients had leukemia cells that expressed ZAP-70 and/or unmutated immunoglobulin variable region genes and 4 patients had either 11q deletions or complex cytogenetics. Six patients interrupted treatment due to adverse events, most of which were transient and without residual complications. Grade 1–2 gastrointestinal effects (e.g., nausea, vomiting) occurred in 11 patients, 2 of whom had grade 3/4 ileus. Six patients experienced treatment-associated fatigue (grade 1–2 in 5 and grade 3 in one). Other than ileus and fatigue the only grade 3/4 event noted was neutropenia. One patient without neutropenia died while undergoing treatment from community-acquired bacterial pneumonia[j1]. Pharmacokinetic studies demonstrated that the average Cmax of AT-101 was 565 ng/ml (280 – 805 ng/ml) at a Tmax of 3.1 hours (1.7 – 5.6 hrs.). Correlative science studies performed on leukemia cells isolated at various times after treatment demonstrated leukemia-cell apoptosis in vivo, with maximum levels seen at times when we observed peak drug levels of AT-101. Eight patients had completed the study and had full response evaluation at the time of this abstract’s submission. The overall response rate was 38% [CRu (2); PR (1); SD (3); PD (2)]. Four of eight patients (50%) had significant reductions in leukemia cell counts and splenomegaly and 5 of 8 (63%) had reductions in lymphadenopathy. AT-101 in combination with Rituximab has apparent activity in patients with relapsed-refractory high-risk CLL. Additional enrollment is planned using alternate AT-101 schedules in an attempt to increase peak plasma concentrations (and potentially activity) and reduce GI toxicity.

Lenalidomide Abrogates the Protective Influence of Nurse-Like Cells on Primary Chronic Lymphocytic Leukemia Cells In Vitro.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 3116-3116 ◽  
Author(s):  
Danelle F. James ◽  
Maryann R. Betty ◽  
Ruzbeh Mosadeghi ◽  
Thomas J. Kipps
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
Cell Viability ◽  
Cell Survival ◽  
Leukemia Cell ◽  
Lymphocytic Leukemia ◽  
Response To Treatment ◽  
Leukemia Cells ◽  
High Dependency ◽  
Cells Cultured

Abstract Lenalidomide (3-(4-amino-1-oxo-3H-isoindol-2-yl)piperidine-2,6-dione)) is an agent approved for treatment of patients with del 5q myelodysplastic syndromes and previously treated multiple myeloma. Lenalidomide has been found in early clinical trials to have potential therapeutic activity in patients with relapsed chronic lymphocytic leukemia (CLL). The mechanism(s) whereby this drug is active in CLL is unknown. In particular, studies to date have not found lenalidomide to have any direct cytotoxic activity on CLL cells in vitro. This has stimulated speculation that this agent might adversely affect the positive influence of the microenvironment on leukemia-cell survival. We and others have observed that cells found in the leukemia microenvironment can support CLL-cell survival in vitro. One such type of cells are nurse-like cells (NLC), which can differentiate from the CD14-positive blood mononuclear cells of CLL patients into large, round adherent cells that can attract and support CLL cell survival in vitro for weeks, if not longer. We evaluated the effects of lenalidomide on primary leukemia-cell survival in vitro when the CLL cells from different patients (N=21) were cultured alone or together with NLC generated as previously described [Tsukada Blood 2002]. We assessed the in-vitro activity of lenalidomide on primary CLL cells from 21 patients, in duplicate in a series of 6 experiments. Lenalidomide at concentrations of 0.1μM-200μM did not significantly impact the survival of CLL cells that were cultured alone for up to 12 days. Analysis of cell surface markers revealed increased expression of CD38 at 36 hours in 5/5 lenalidomide treated CLL samples compared with untreated cells (MFIR 5.7 +/− .86 vs. 3.4 +/− .83 p=.003). We observed sustained upregualtion of CD40 and regulation of CXCR4 in the majority of cells treated with lenalidomide. When cultured with NLC, the survival of CLL cells was comparable to or significantly higher than that of CLL cells cultured alone 62.4% vs. 51% (+/−3% SEM n=21 p [<] 0.0005). The addition of lenalidomide at concentrations of 0.1μM and greater to co-cultures of NLC and CLL cells caused specific reductions in CLL cell survival to levels similar to or lower than that of CLL cells cultured without NLC. In the presence of NLC, lenalidomide at 1μM reduced CLL cell viability compared to control (41.5% vs. 56% +/−4% p [<] 0.0005 paired student t test n=13). For most patients the levels of CLL cell viability on days 4 through 8 in the co-cultures with lenalidomide was significantly lower than those of CLL cells co-cultured with NLC in the absence of lenalidomide. As such, this study reveals that physiologic concentrations of lenalidomide might abrogate the protective influence of NLC on CLL cell survival in vitro and potentially in vivo. Conceivably, those patients who have leukemia cells displaying a high dependency on NLC for survival in vitro also might be most likely to experience a favorable clinical response to treatment with lenalidomide. This hypothesis will be tested in a prospective manner with a planned clinical trial evaluating lenalidomide for treatment of CLL through the CLL Research Consortium.

B Cell Activating Factor and c-Myc Regulate the Progression of Chronic Lymphocytic Leukemia.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 359-359
Author(s):  
Weizhou Zhang ◽  
Arnon P. Kater ◽  
Han-Yu Chuang ◽  
Thomas Enzler ◽  
George F. Widhopf ◽  
...  
Keyword(s):  
Bone Marrow ◽  
B Cells ◽  
Chronic Lymphocytic Leukemia ◽  
B Cell ◽  
Disease Progression ◽  
Cell Population ◽  
Lymphocytic Leukemia ◽  
Leukemia Cells ◽  
Low Grade ◽  
B Cell Activating Factor

Abstract Abstract 359 Chromosomal translocations involving c-Myc are frequently found in high grade lymphoma and multiple myeloma. In contrast, c-Myc translocations rarely occur in low-grade lymphomas/leukemias like chronic lymphocytic leukemia (CLL), but when present they are associated with rapid disease progression and bad prognosis. Overexpression of c-myc may also be the result of increased transcription by several proto-oncogene transcription factors, including NF-kB. Mice with c-Myc de-regulation at different stages of B cell development develop either aggressive B cells lymphomas or plasma cell neoplasm. So far, no c-Myc mouse model developed low-grade lymphoma/leukemia. iMycCa mice develop an expansion of CD5+ peritoneal B1 cells, as compared with WT littermates mice. These mice have a normal life-span and very rarely develop B cell lymphoma at older age. Interestingly, in iMycCa mice mature B cells, but not plasma cells,could be rescued from apoptosis by administration of B cell-activating factor belonging to the TNF family (BAFF). To our surprise, double transgenic iMycCa/Baff-Tg (Myc/Baff) mice developed a disease resembling human CLL, with dramatically shorter mean survival than parental strains, due to early onset and rapid clonal expansion of a mature CD5+B220low B cell population. Those cells transferred the disease into Baff-Tg (Baff) mice with marked infiltration in lymphoid organs and bone marrow. Gene-expression analyses revealed that among the genes altered in Myc/Baff CD5+B220lowleukemia cells were those with known relevance to human CLL disease, including elevated anti-apoptotic Bcl2 family members. Apart from studies on individual genes, sub-network analysis was performed which showed enrichment of apoptosis-related and stress-induced gene sets in Myc/Baff CD5+CD3- leukemia cells. The NF-kB gene set, a major target downstream of BAFF signaling, was also enriched in Myc/Baff CD5+CD3- leukemia cells. We observed a continuum in levels of c-MYC mRNA in 166 samples using Affymetrix array analyses. Changes in c-Myc protein expression were confirmed by immunoblot analyses and correlated with disease progression. In accordance with the functions of c-Myc as a promoter of cell cycle progression, as well as apoptosis, we found enhanced spontaneous cell death in vitro in CLL cells expressing high levels of c-Myc, which could be abrogated by co culture with BAFF expressing nurse-like cells (NLC) or recombinant BAFF. In addition to its anti-apoptotic role, BAFF treatment of primary human CLL cells led to dramatically enhanced expression of c-Myc through the IKK/NF-kB pathway. Inhibition of the NF-kB pathway significantly reduced viability of both Myc/Baff CD5+CD3- leukemia cells and human CLL cells co-cultured with NLC. Also it significantly lowered CD5+B220low leukemia cell population in blood and spleen, and prevented the infiltration of leukemia cells into lymph nodes and bone marrow of transplanted mice. This study demonstrates a potential pathologic role for c-Myc, in the pathogenesis and progression of CLL. Disclosures: No relevant conflicts of interest to declare.

Targeting of Chronic Lymphocytic Leukemia B Cells with a Novel Monoclonal Antibody to ROR1

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 984-984
Author(s):  
Bing CUi ◽  
George F. Widhopf ◽  
Jian Yu ◽  
Daniel Martinez ◽  
Esther Avery ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
B Cells ◽  
Chronic Lymphocytic Leukemia ◽  
Adoptive Transfer ◽  
Leukemia Cell ◽  
Lymphocytic Leukemia ◽  
Leukemia Cells ◽  
Human Leukemia ◽  
Phosphorylated Akt

Abstract Abstract 984 ROR1 is an orphan receptor tyrosine kinase that is expressed on leukemia cells of patients with chronic lymphocytic leukemia (CLL), but not on most adult tissues of healthy adults, including CD5+ B cells. To generate anti-ROR1 antibodies, we immunized mice using different strategies employing vaccines comprised of recombinant ROR1 protein, polynucleotide-ROR1 vaccines and CD154 genetic adjuvants, or replication-defective adenovirus vectors encoding ROR1 and CD154. We extirpated the spleens of animals that developed high-titer serum anti-ROR1 antibodies and used these to generate monoclonal-antibody-(mAb)-producing hybridomas or antibody phage-display libraries that subsequently were screened for ROR1-binding. Over 70 unique mAbs were generated that each bound the extra-cellular domain of native ROR1. Most mAbs recognized an epitope(s) within the ROR1 Ig-like domain, which appears to represent the immune dominant epitope. Other mAb recognized epitopes within the conserved ROR1 Kringle domain. One mAb (UC D10-001) had distinctive binding to an intradomain epitope of human ROR1 (hROR1). UC D10-001 was the only mAb we found directly cytotoxic for hROR1-expressing leukemia cells cultured in media without complement for 6 hours. We found that UC D10-001 could induce significant reductions in basal levels of phosphorylated AKT in hROR1-expressing leukemia cells. Moreover, UC D10-001 significantly decreased the basal levels of phosphorylated AKT in freshly isolated human CLL cells (N=4) to levels comparable to that observed in co-cultures containing 10 mM LY294002, a broad-spectrum inhibitor of PI3K. We examined whether this mAb had cytotoxic activity for leukemia cell in vivo. For this we examined whether we could inhibit the adoptive transfer of human-ROR1-expressing leukemia cells to young, syngeneic recipient mice made transgenic for human ROR1 under control of a B-cell specific promoter. Cohorts of 5 animals per group were each given intravenous injections of antibody at a dose of at 10 mg/kg. Each cohort was treated with UC D10-001, control IgG, or 4A5, an anti-ROR1 mAb specific for a non-cross-reactive epitope located in the Ig-like domain of ROR1. Each animal received an intravenous injection of 5 × 105 ROR1-expressing leukemia cells and then was assessed weekly for circulating leukemia cells by flow cytometry. UC D10-001, but not control IgG or 4A5, significantly inhibited engraftment of the ROR1+ leukemia. Four weeks after adoptive transfer, animals treated with UC D10-001 had a 10-fold lower median number of leukemia B cells in the blood than animals treated with control IgG or 4A5. We also tested UC D10-001 for its capacity to induce clearance of human ROR1+ CLL cells engrafted into the peritoneal cavity of Rag-2−/−/γc−/− immune deficient mice. Each of these mice received intraperitoneal injections of equal numbers of human ROR1+ CLL cells prior to receiving D10-001, control IgG, or 4A5, each at 10 mg/kg. These animals were sacrificed seven days later and the human leukemia cells were harvested via peritoneal lavage. In mice treated with UC D10-001 we harvested an average of only 6 × 104 ± 3 × 104 CLL cells. This number of cells was significantly less than the average number of CLL cells harvested from control IgG or 4A5-treated mice (8 × 105 ± 4 × 105 or 7 × 105 ± 2 × 105, respectively, p <0.01). These studies indicate that the anti-ROR1 mAb UC D10-001 can be directly cytotoxic for ROR1-expressing leukemia cells in vitro and in vivo, a property that apparently is unique to this mAb among other anti-ROR1 mAbs. Because of the restricted expression of ROR1 on leukemia cells and the distinctive properties of this mAb, we propose that UC D10-001 might have potential utility in the treatment of patients with CLL. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Cirmtuzumab Targets ROR1 to Inhibit Ibrutinib-Resistant, Wnt5a-Induced Rac1 Activation in Chronic Lymphocytic Leukemia

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 2034-2034 ◽  
Author(s):  
Jian Yu ◽  
Liguang Chen ◽  
Bing Cui ◽  
Christina Wu ◽  
Michael Y. Choi ◽  
...  
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
B Cell ◽  
Research Funding ◽  
Standard Dose ◽  
Leukemia Cell ◽  
Lymphocytic Leukemia ◽  
Leukemia Cells ◽  
Human Leukemia ◽  
Synergistic Activity ◽  
Bcr Signaling

Abstract Signaling via the B cell receptor (BCR) plays an important role in the pathogenesis and progression of chronic lymphocytic leukemia (CLL). This is underscored by the clinical effectiveness of an inhibitor of Bruton's tyrosine kinase (BTK), ibrutinib, which can block BCR-signaling. However, ibrutinib cannot induce complete responses (CR) or durable remissions without continued therapy, suggesting that ancillary pathways contribute to CLL growth/survival that are independent of BCR-signaling. ROR1 is a receptor for Wnt5a, which can promote activation of Rac1 to enhance CLL-cell proliferation and survival. We hypothesized that the effects of ibrutinib on blocking BCR-signaling might be offset by non-canonical Wnt-signaling via ROR1. If so, then inhibition of both ROR1- and BCR-signaling might have an enhanced anti-tumor effect. We examined the CLL cells of patients who were taking ibrutinib at the standard dose of 420 mg per day. Freshly isolated CLL cells had activated Rac1, which diminished over time upon culture in serum-free media, unless treated with exogenous Wnt5a, as noted for CLL cells of patients not taking ibrutinib. Moreover, Wnt5a could induce Rac1 activation and enhance proliferation of CLL cells treated in vitro with ibrutinib, even at concentrations that exceeded those required to completely inhibit BTK and BCR-signaling. On the other hand, Wnt5a-induced activation of Rac1 was blocked by treatment of the CLL cells with cirmtuzumab (UC-961), a first-in-class humanized mAb specific for a functional extracellular epitope of ROR1; this mAb is being evaluated in a phase I clinical trial in patients with CLL. To examine the activity of ibrutinib and/or cirmtuzumab, alone or in combination, we transferred human CLL cells into the peritoneal cavity of immune-deficient Rag2−/−γc−/− mice, which subsequently were treated with ibrutinib via oral gavage and/or cirmtuzumab administered iv. Although either agent alone resulted in some leukemia-cell clearance, cirmtuzumab and ibrutinib had apparent synergistic activity when used together in clearing human leukemia cells. We also examined the activity of each agent, alone or in combination, against a ROR1+ mouse leukemia, which we had engrafted in Rag2−/−γc−/− mice. While the engrafted mice treated with cirmtuzumab or ibrutinib alone had significantly smaller spleens and lower proportions of leukemia cells than the engrafted animals that did not receive any treatment, the mice treated with the combination of cirmtuzumab and ibrutinib had significantly smaller spleens and synergistic clearance of leukemia cells. Collectively, this study demonstrates that cirmtuzumab and ibrutinib may have synergistic activity in the treatment of patients with CLL, providing the rationale for clinical trials using cirmtuzumab in combination with ibrutinib, or another inhibitor of BTK, such as acalabrutinib, for treatment of patients with CLL or other B-cell malignancies dependent on non-canonical Wnt5a/ROR1 signaling. Disclosures Kipps: Celgene: Consultancy, Honoraria, Research Funding; Pharmacyclics, LLC, an AbbVie Company: Consultancy, Honoraria; Gilead: Consultancy, Honoraria, Speakers Bureau; Roche: Consultancy, Honoraria; AbbVie: Consultancy, Honoraria, Research Funding.

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.

CD40-ligand (CD154) gene therapy for chronic lymphocytic leukemia

Blood ◽  
2000 ◽  
Vol 96 (9) ◽  
pp. 2917-2924 ◽  
Author(s):  
William G. Wierda ◽  
Mark J. Cantwell ◽  
Sandra J. Woods ◽  
Laura Z. Rassenti ◽  
Charles E. Prussak ◽  
...  
Keyword(s):  
Gene Therapy ◽  
T Cell ◽  
Chronic Lymphocytic Leukemia ◽  
De Novo ◽  
Leukemia Cell ◽  
Cd40 Ligand ◽  
Lymphocytic Leukemia ◽  
Leukemia Cells ◽  
Interleukin 12 ◽  
Cell Counts

Chronic lymphocytic leukemia (CLL) cells can be made to express recombinant CD40-ligand (CD154) by transduction with a replication-defective adenovirus vector (Ad-CD154). Ad-CD154–transduced and bystander leukemia cells become highly effective antigen-presenting cells that can induce CLL-specific autologous cytotoxic T lymphocytes in vitro. This study investigated the immunologic and clinical responses to infusion of autologous Ad-CD154-CLL cells in patients with CLL. After a one-time bolus infusion of autologous Ad-CD154–transduced leukemia cells, there was increased or de novo expression of immune accessory molecules on bystander, noninfected CLL cells in vivo. Treated patients also developed high plasma levels of interleukin-12 and interferon-γ, the magnitudes of which corresponded to absolute blood CD4+T-cell counts before therapy. On average, patients experienced a greater than 240% increase in absolute blood T-cell counts within 1 to 4 weeks of treatment. Moreover, treatment increased the numbers of leukemia-specific T cells, demonstrated by autologous ELISPOT assay and mixed lymphocyte reactions. These biologic effects were associated with reductions in leukemia cell counts and lymph node size. Treatment did not induce autoimmune thrombocytopenia or hemolytic anemia and no dose-limiting toxicity was observed. This approach may provide a novel and effective form of gene therapy for patients with this disease.

ICOS Is Induced by B Cell Receptor Signalling on Chronic Lymphocytic Leukemia B Cells.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 969-969 ◽  
Author(s):  
Tetsuya Fukuda ◽  
Traci L. Toy ◽  
Laura Z. Rassenti ◽  
Kanti R. Rai ◽  
Thomas J. Kipps
Keyword(s):  
Flow Cytometry ◽  
T Cells ◽  
B Cells ◽  
Chronic Lymphocytic Leukemia ◽  
B Cell ◽  
Progressive Disease ◽  
Leukemia Cell ◽  
Lymphocytic Leukemia ◽  
Leukemia Cells ◽  
Activated T Cells

Abstract Patients with chronic lymphocytic leukemia (CLL) cells that express unmutated immunoglobulin (Ig) heavy chain variable region genes (IgVH genes) generally have a more aggressive clinical course than do patients with leukemia cells that express mutated IgVH. The reason(s) accounting for this are not known. Microarray gene expression analyses revealed that CLL cells that express unmutated IgVH could be distinguished from the leukemia cells that express mutated IgVH via the differential expression of a relatively small number of genes, one of which encodes the zeta-associated chain of 70kD (ZAP-70), which generally is expressed by CLL cells that express unmutated IgVH. Although the expression of ZAP-70 is associated with expression of unmutated IgVH in CLL, this association is not absolute. This was the case for a pair of monozygotic twins who both developed CLL at age 57. Although each of the twins had leukemia cells that expressed mutated IgVH, only one of the twins had leukemia cells that lacked expression of ZAP-70 protein and has indolent, non-progressive disease (Blood100: 4609–14, 2002). We performed microarray analysis using Affymetrix HG-U133A array on the isolated leukemia cells of each twin to define the genes that were differentially expressed between the two. In addition to ZAP-70, we found that the CLL cells of the twin with progressive disease also expressed the inducible co-stimulatory molecule (ICOS), a member of the CD28/CTLA-4 family of immune accessory co-stimulatory molecules that ordinarily only is expressed by activated T cells. Expression of ICOS protein by this leukemia B cell population, but not by the CLL B cells population of the other twin, was confirmed using fluorochrome-labeled anti-ICOS mAb and flow cytometry. We examined the CLL B cells from 58 additional patients for expression of ICOS by flow cytometry and found that 16 (28%) also expressed ICOS. We found that expression of ICOS was associated with expression of ZAP-70, as assessed via flow cytometry and immunoblot analyses. Whereas 14 of the 29 ZAP-70+ cases expressed ICOS, only 2 of the 29 ZAP-70-negative cases expressed this immune co-stimulatory molecule. Nevertheless, we found that nearly all of the 56 of the 58 cases expressed B7h, the ligand for ICOS. The two cases that did not express detectable B7h expressed ZAP-70 and were ICOS+. In preliminary studies, we found that treatment of ICOS-negative, ZAP-70+ CLL cells (n = 2) with goat anti-human Ig could induce expression of ICOS, suggesting that, as on T cells, this molecule also might be inducible in some cases of B cell CLL. Culture of ICOS+ CLL cells with an anti-B7h mAb capable of blocking ICOS-B7h interactions significantly enhanced ICOS surface expression, as assess by flow cytometry, suggesting that B7h may down-modulate ICOS through paracrine/autocrine receptor-ligand interactions. Because of this we evaluated for functional expression of ICOS on CLL B cells. We found that ligation of ICOS could induce enhanced signaling via the PI3K/Akt pathway in isolated CLL B cells, resulting in enhanced phosphorylation and activation of Akt. As such, we speculate that the expression of ICOS and its ligand in B cell CLL may enhance leukemia cell survival and/or proliferation, potentially contributing to the more aggressive disease observed in some patients with this disease.

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