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Beider Katia,
Elena Ribakovsky,
Michal Abraham,
Hanna Wald,
Lola Weiss,
Evgenia Rosenberg,
Eithan Galun,
Abraham Avigdor,
Orly Eizenberg,
Amnon Peled, Arnon Nagler
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ABSTRACT: PURPOSE: Chemokine axis CXCR4/CXCL12 is critically involved in the survival and trafficking of normal and malignant B lymphocytes. Here, we investigated the effect of high affinity CXCR4 antagonist BKT140 on lymphoma cell growth and rituximab-induced cytotoxicity in vitro and in vivo. EXPERIMENTAL DESIGN: In vitro efficacy of BKT140 alone or in combination with rituximab was determined in NHL cell lines and primary samples from BM aspirates of NHL patients. In vivo efficacy was evaluated in xenograft models of localized and disseminated NHL with BM involvement. RESULTS: Antagonizing CXCR4 with BKT140 resulted in significant inhibition of CD20+ lymphoma cell growth and in the induction of cell death. Combination of BKT140 with rituximab significantly enhanced the apoptosis against the lymphoma cells in a dose-dependent manner. Moreover, rituximab induced CXCR4 expression in lymphoma cell lines and primary lymphoma cells. Primary BMSCs further increased CXCR4 expression and protected NHL cells from rituximab-induced apoptosis, while BKT140 abrogated this protective effect. Furthermore, BKT140 demonstrated efficient anti-lymphoma activity in vivo in the xenograft model of disseminated NHL with BM involvement. BKT140 treatment inhibited the local tumor progression and significantly reduced the number of NHL cells in the BM. Combined treatment of BKT140 with rituximab further decreased the number of viable lymphoma cells in the BM, achieving 93% reduction. CONCLUSIONS: These findings suggest the possible role of CXCR4 in NHL progression and response to rituximab, and provide the scientific basis for the development of novel CXCR4-targeted therapies for refractory NHL.
Clinical Cancer Research 05/2013; · 7.74 Impact Factor
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ABSTRACT: Chronic graft-versus-host disease (GVHD) is a severe complication of allogeneic stem cell transplantation, with a substantial impact on the quality of life and survival, still lacking with regard to an optimal therapeutic strategy. Corticosteroids are considered the standard of care for first-line treatment of chronic GVHD, but only a minority of the patients responds to them durably. Management of steroid-refractory chronic GVHD is not well defined. This review surveys novel treatment strategies, such as therapies that expand regulatory T cells, target B cells or target the processes implicated in fibrosis that may allow more effective control of chronic GVHD in the future. Most therapies are based solely on phase II trials or on retrospective analyses with a wide range of overall responses. Large, well-designed prospective studies are eagerly needed to establish better treatments, as well as valid biomarkers to identify the likelihood of the response to a drug in advance.
Acta Haematologica 02/2013; 130(1):34-43. · 1.35 Impact Factor
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ABSTRACT: BACKGROUND
Hematopoietic growth factors (HGFs) are mostly used as supportive measures to reduce infectious complications associated with neutropenia. Over the past decade, the use of HGFs became a common method for mobilizing human CD34+ stem cells, either for autologous or allogeneic transplantation. However, since their introduction the long-term safety of the procedure has become a major focus of discussion and research. Most information refers to healthy normal donors and data concerning pregnant and lactating women are scarce. The clinical question, which is the core of this review, is whether stem cell donation, preceded by administration of granulocyte-colony stimulating factor (G-CSF) for mobilization, is a safe procedure for pregnant donors.METHODS
Literature searches were performed in Pubmed for English language articles published before the end of May 2012, focusing on G-CSF administration during pregnancy, lactation and hematopoietic stem cell donation. Searches included animal and human studies.RESULTSData from animals (n = 15 studies) and women (n = 46 studies) indicate that G-CSF crosses the placenta, stimulates fetal granulopoiesis, improves neonatal survival mostly for very immature infants, promotes trophoblast growth and placental metabolism and has an anti-abortive role. Granulocyte macrophage-CSF is a key cytokine in the maternal immune tolerance towards the implanted embryo and exerts protective long-term programming effects to preimplantation embryos. The available data suggest that probably CSFs should not be administered during the time of most active organogenesis (first trimester), except perhaps for the first week during which implantation takes place. Provided CSF is administered during the second and third trimesters, it appears to be safe, and pregnant women receiving the CSF treatment can become hematopoietic stem cell donors. There are also risks related to the anesthesia, which is required for the bone marrow aspiration. During lactation, there should be a period of at least 3 days to allow for clearance of CSF from milk before resuming breast feeding. With regard to teratogenicity or leukaemogenity, in non-pregnant or non-lactating women reports show that CSF administration is associated with a risk for leukemia; however, this risk is not higher compared with the control population.CONCLUSIONS
The information available to date indicates that administration of CSF in general, and G-CSF in particular, is safe and healthy pregnant women can serve as donors of either bone marrow or peripheral blood stem cells. However, the clinical experience is rather limited and therefore until more data become available, G-CSF should not be used during pregnancy and lactation when other therapeutic options, instead of stem cell transplantation, are available.
Human Reproduction Update 01/2013; · 9.23 Impact Factor
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ABSTRACT: Acute graft-versus-host disease (GVHD) is a major source of morbidity and mortality after allogeneic stem cell transplantation. Therapy of established acute GVHD depends heavily on corticosteroids, which have limited efficacy and are considerably toxic. It is still a matter of debate whether there is an alternative therapy to corticosteroids. Second-line treatment for acute GVHD after failure of steroidsis not well substantiated due to the lack of controlled studie This review examines the current treatment for acute GVHD, as well as novel therapeutics, such as cellular approlaches (e.g., adoptive transfer of mesenchymal stem cellt) and , enhancement of regulatory T cells (e.g., photopheresis). These approaches avoid the toxicity of generalized immunosuppression and are likely to play a prominent futurer ole in acute GVHD therapy.
The Israel Medical Association journal: IMAJ 01/2013; 15(1):44-50. · 1.02 Impact Factor
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ABSTRACT: Natural killer (NK) cells have long been considered as potential agents for adoptive cell therapy for solid cancer patients. Until today most studies utilized autologous NK cells and yielded disappointing results. Here we analyze various modular strategies to employ allogeneic NK cells for adoptive cell transfer, including donor-recipient HLA-C mismatching, selective activation and induction of melanoma-recognizing lysis receptors, and co-administration of antibodies to elicit antibody-dependent cell cytotoxicity (ADCC). We show that NK cell activation and induction of the relevant lysis receptors, as well as co-administration of antibodies yield substantial anti-cancer effects, which are functionally superior to HLA-C mismatching. Combination of the various strategies yielded improved effects. In addition, we developed various clinically-compatible ex vivo expansion protocols that were optimized according to fold expansion, purity and expression of lysis receptors. The main advantages of employing allogeneic NK cells are accessibility, the ability to use a single donor for many patients, combination with various strategies associated with the mechanism of action, e.g. antibodies and specific activation, as well as donor selection according to HLA or CD16 genotypes. This study rationalizes a clinical trial that combines adoptive transfer of highly potent allogeneic NK cells and antibody therapy.
PLoS ONE 01/2013; 8(3):e57922. · 4.09 Impact Factor
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ABSTRACT: The ability to sequence nucleic acids at an unprecedented pace and decreased costs using massive parallel sequencing (MPS) strongly affects biomedical research. Here we applied MPS for the detection of rare, clinically relevant mutations in a chronic myeloid leukaemia (CML) patient. Tyrosine kinase inhibitors revolutionized CML therapy but in some patients the disease progresses due to resistance-conferring mutations. MPS was applied herein to monitor such mutations in BCR-ABL1 transcripts at different time points. The large volume of sequencing data increases sensitivity compared to direct sequencing and allows detection of marginally represented and previously uncharacterized mutations. We detected changes in the frequency of mutated clones including the emergence and disappearance of the resistance-associated ABL1 T315I mutation. We also observed correlation in appearance of adjacent mutations, and exploited this observation to demonstrate the existence of mutated clones at the time of diagnosis. A tool is provided for detection of low frequency single nucleotide variants/mutations from deep coverage MPS data, applicable to clinical translation of advanced sequencing technologies.
British Journal of Haematology 12/2012; · 4.94 Impact Factor
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ABSTRACT: Umbilical cord blood (CB) stem cells have been proposed for cell-based therapeutic applications for diverse diseases of the CNS. We hypothesized that tissue-engineering strategies may extend the efficacy of these approaches by improving the long-term viability and function of stem cell-derived neuronal progenitors. To test our hypothesis, we explored the survival and differentiation of human CB-derived neuronal progenitors (HUCBNP) in a three-dimensional (3D) collagen construct. In contrast to two-dimensional culture conditions, the cells survived in 3D for an extended period of time of more than 2 months. Under 3D conditions, HUCBNP underwent spontaneous neuronal differentiation, which was further enhanced by treatment with neuronal conditioned medium (CM) and nerve growth factor (NGF). Neurite outgrowth, quantified by assessing the fractal dimension (D (f)) of the complex neuronal networks, was significantly enhanced under 3D conditions in the presence of CM/NGF, concomitant with a reduced expression of the early neuronal marker nestin (1.9-fold), and increased levels of mature neuronal markers such as MAP-2 (3.6-fold), β-tubulin (1.5-fold), and neuronal specific enolase (6.6-fold) and the appearance of the synaptic marker synaptophysin. To assess the feasibility for clinical usage, HUCBNP were also isolated from frozen CB samples and cultured under 3D conditions. The data indicate the essential complete preservation of neurotrophic (survival) and neurotropic (neurite outgrowth) properties. In conclusion, 3D culture conditions are proposed as an essential step for both maintenance of CB neuronal progenitors in vitro and for investigating specific features of neuronal differentiation towards future use in regenerative therapy.
Journal of Molecular Neuroscience 12/2012; · 2.50 Impact Factor
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ABSTRACT: Multiple myeloma (MM) is a life-threatening hematological malignancy. High-dose chemotherapy followed by autologous stem cell transplantation is a relatively effective treatment, but disease recurrence remains a major obstacle. Allogeneic transplantation may result in durable responses and cure due to antitumor immunity mediated by donor lymphocytes. However, morbidity and mortality related to graft-versus-host disease remain a challenge. Recent advances in understanding the interaction between the immune system of the patient and the malignant cells are influencing the design of clinically more efficient study protocols for MM. This review will focus on MM antigens and their specific antibodies. These monoclonal antibodies are an attractive therapeutic tool for MM humoral immunotherapy, with most promising preclinical results.
Immunotherapy 09/2012; 4(9):919-38. · 1.85 Impact Factor
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Evgeny Klyuchnikov,
Ernst Holler,
Martin Bornhäuser,
Guido Kobbe, Arnon Nagler,
Avichai Shimoni,
Christian Könecke,
Christine Wolschke,
Ulrike Bacher,
Axel R Zander,
Nicolaus Kröger
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ABSTRACT: Thirty myelofibrosis patients (21 males, nine females) with relapse (n = 27) or graft-rejection (n = 3) after dose-reduced allografting underwent a salvage strategy including donor lymphocyte infusions (DLIs) and/or second allogeneic haematopoietic stem cell transplantation (HSCT). Twenty-six patients received a median number of three (range, 1-5) DLIs in a dose-escalated mode starting with a median dose of 1·2 × 10(6) (range, 0·003-8 × 10(6) ) up to median dose of 40 × 10(6) T-cells/kg (range, 10-130 × 10(6) ). 10/26 patients (39%) achieved complete response (CR) to DLIs. Acute (grade II-IV) and chronic graft-versus-host (GvHD) disease occurred in 12% and 36% cases. Thirteen non-responders to DLI and four patients who did not receive DLI due to graft-rejection or acute transformation of the blast phase underwent a second allogeneic HSCT from alternative (n = 15) or the same (n = 2) donor. One patient (6%) experienced primary graft-failure and died. Acute (II-IV) and chronic GvHD were observed in 47% and 46% of patients. Overall responses after second HSCT were seen in 12/15 patients (80%: CR: n = 9, partial response: n = 3). The 1-year cumulative incidence of non-relapse mortality for recipients of a second allograft was 6%, and the cumulative incidence of relapse was 24%. After a median follow-up of 27 months, the 2-year overall survival and progression-free survival for all 30 patients was 70% and 67%, respectively. In conclusion, our two-step strategy, including DLI and second HSCT for non-responding or ineligible patients, is an effective and well-tolerated salvage approach for patients relapsing after reduced-intensity allograft after myelofibrosis.
British Journal of Haematology 08/2012; 159(2):172-81. · 4.94 Impact Factor
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ABSTRACT: Halofuginone, a low-molecular-weight quinazolinone alkaloid that inhibits collagen α1(I), has been shown to suppress cancer growth, metastasis, and angiogenesis. These activities were attributed in part to the inhibition of matrix metalloproteinase-2 (MMP-2). The present study was carried out to explore the molecular mechanism underlying this effect. We found a marked (50%) inhibition in MMP-2 gelatinolytic activity in human breast cancer MDA-MB-435 cells pretreated with as little as 50 ng/ml of halofuginone, a concentration that markedly inhibited their invasive and proliferative capacities. We further show that both early growth response 1 (Egr-1) and Nab-2 (corepressor of Egr1 activation) are upregulated by halofuginone in a dose-dependent and time-dependent (up to 5 h) manner. Using MMP-2 reporter gene and chromatin immunoprecipitation analyses, we found that Egr-1 binds to the MMP-2 promoter and inhibits its activity. Altogether, our results identify the downstream elements (Egr-1, Nab-2, and MMP-2) by which halofuginone exerts its antitumoral effect, thereby advancing its potential therapeutic application as an anticancer drug.
Anti-cancer drugs 08/2012; 23(10):1022-31. · 2.23 Impact Factor
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ABSTRACT: Chronic myeloid leukemia (CML) is a clonal hematological disease that represents 15-20% of all adult leukemia cases. The study and treatment of CML has contributed pivotal advances to translational medicine and cancer therapy. The discovery that a single chromosomal abnormality, the Philadelphia (Ph) chromosome, is responsible for the etiology of this disease was a milestone for treating and understanding CML. Subsequently, CML became the first disease for which allogeneic bone marrow transplantation is the treatment of choice. Currently, CML is one of the few diseases where treatment targeted against the chromosomal abnormality is the sole frontline therapy for newly diagnosed patients. The use of directed therapy for CML challenged disease monitoring during treatment and led to the development of definitions that document response and predict relapse sooner than the former routine methods. These methods relied on classical cytogenetics through molecular cytogenetics (FISH) and, finally, on molecular monitoring assays. This review discusses the laboratory tools used for diagnosing CML, for monitoring during treatment, and for assessing remission or relapse. The advantages and disadvantages of each test, the common definition of response levels, and the efforts to standardize molecular monitoring for CML patient management are discussed.
The Israel Medical Association journal: IMAJ 08/2012; 14(8):501-7. · 1.02 Impact Factor
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Patrice Chevallier,
Myriam Labopin,
Stefanie Buchholz,
Arnold Ganser,
Fabio Ciceri,
Bruno Lioure,
Chistoph Faul,
Gaelle Guillerm,
Juergen Finke,
Anne Huynh,
Joerg Schubert,
Hans-Jochem Kolb,
Emmanuelle Polge, Arnon Nagler,
Mohamad Mohty
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ABSTRACT: Clofarabine (CLO), a second-generation purine analogue, has demonstrated an efficient anti-leukemia activity while showing a favorable toxicity profile. This retrospective multicenter report assessed the outcome of 90 patients who received a CLO-containing conditioning regimen before allo-SCT for AML (n = 69) or ALL (n = 21). Median age was 42 yr at transplant. The majority of cases (n = 66) presented with an active disease at transplant while 38 patients had received previous transplantation(s). A total of 88 and two patients received a reduced-intensity conditioning or a myeloablative regimen, respectively. Engraftment was achieved in 97% of evaluable patients. With a median follow-up of 14 months (range, 1-45), the 2-year OS, LFS, relapse, and NRM rates were 28 ± 5%, 23 ± 5%, 41 ± 6%, and 35 ± 5%, respectively. When comparing AML and ALL patients, OS and LFS were significantly higher for AML (OS, 35 ± 6% vs. 0%, P < 0.0001); LFS: 30 ± 6% vs. 0%, P < 0.0001). In a Cox multivariate analysis, an AML diagnosis was the only factor associated with a better LFS (HR = 0.37; 95%CI, 0.21-0.66; P = 0.001). We conclude that a CLO-containing conditioning regimen prior to allo-SCT might be an effective treatment. Prospective studies are needed to evaluate the potential role of CLO as part of conditioning regimens in acute leukemias.
European Journal Of Haematology 06/2012; 89(3):214-9. · 2.61 Impact Factor
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ABSTRACT: Abstract Allogeneic hematopoietic stem cell transplantation (HST) is an important therapeutic option for various malignant and non-malignant conditions. HST during first remission offers the best cure for patients for whom conventional chemotherapy alone is not sufficient. Yet, in spite of the high curative potential and recent advances in this treatment modality, it remains limited by transplant related toxicity and grant-versus-host disease (GVHD). Apoptotic cells, which used to be regarded as immunologically "bland," are now recognized as important modulators of immune responses. Taking into account the immunological properties of apoptotic cells and the nature of the side effects of HST, they have been administered simultaneously with hematopoietic stem cells in experimental transplantation models, in anticipation of improved outcome. Under these conditions, engraftment and full-donor chimerism are facilitated without significant generation of anti-apoptotic cell auto-antibodies. In addition they prevent alloimmunization, up-regulate T regulatory cells and reduce both the frequency and the severity of GVHD. These favorable effects require host macrophages and donor bone marrow plasmatoid dendritic cells, and are associated with tumor growth factor-β (TGF-β) production. To summarize, apoptotic cells can play a crucial role in the setting of transplantations, and may be viewed as "turning trash into gold." Clinical studies are underway.
Leukemia & lymphoma 05/2012; 53(11):2130-5. · 2.40 Impact Factor
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Kate Cwynarski,
Anja van Biezen,
Liesbeth de Wreede,
Stephan Stilgenbauer,
Donald Bunjes,
Bernd Metzner,
Vladimir Koza,
Mohamad Mohty,
Kari Remes,
Nigel Russell, Arnon Nagler,
Marijke Scholten,
Theo de Witte,
Anna Sureda,
Peter Dreger
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ABSTRACT: Patients with Richter's syndrome (RS) have a poor prognosis with conventional chemotherapy. The aim of this study was to evaluate the outcome after autologous stem-cell transplantation (autoSCT) or allogeneic stem-cell transplantation (alloSCT) in RS.
A survey was sent to all European Group for Blood and Marrow Transplantation centers assessing transplantations performed for RS. Eligibility criteria included a diagnosis of RS or secondary lymphoma before SCT, age ≥ 18 years, and SCT performed from 1997 to 2007. Data were analyzed by descriptive statistics and methods from survival analysis.
Fifty-nine patients were registered. Thirty-four patients had received autoSCT, mostly because of chemotherapy-sensitive disease, and 25 had received alloSCT, with 36% being refractory to chemotherapy at SCT. In 18 allograft recipients (72%), reduced-intensity conditioning (RIC) was used. Three-year estimates of the probabilities of overall survival and relapse-free survival (RFS) and the cumulative incidences of relapse and nonrelapse mortality were 36%, 27%, 47%, and 26% for alloSCT and 59%, 45%, 43%, and 12% for autoSCT, respectively. Taking into account the limitations set by the low number of events and age younger than 60 years, chemotherapy-sensitive disease and RIC were found to be associated with superior RFS after alloSCT in multivariate analysis. Factors with a significant impact on autoSCT could not be identified.
Patients with RS who are sensitive to induction chemotherapy appear to benefit from consolidation with transplantation strategies, and prolonged survival was observed in a proportion of patients.
Journal of Clinical Oncology 04/2012; 30(18):2211-7. · 18.37 Impact Factor
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ABSTRACT: Abstract The JAK2V617F mutation has emerged in recent years as a diagnostic as well as treatment target in patients with polycythemia vera (PV). We analyzed JAK2V617F allele burden (JAK2(V617F)) in a Jewish population with PV. Results were correlated with disease symptoms and complications. Median JAK2(V617F) was 48% and 54% in patients of Ashkenazi and non-Ashkenazi origin, respectively (p =0.75). Higher JAK2(V617F) was seen in patients with imaging-proven splenomegaly (p =0.01). A correlation between JAK2(V617F) and the weekly hydoxyurea dose needed for disease control was found (p =0.043). In addition, a trend for higher allele burden in patients with longer disease duration (p =0.064) and those treated with cytoreductive drugs other than hydroxyurea (p =0.056) was noted. Higher JAK2(V617F) was seen in patients with transformation to myelofibosis (p =0.0001), but not in patients with vascular complications. JAK2(V617F) may assist in prognostic stratification of patients with PV.
Leukemia & lymphoma 04/2012; 53(11):2210-3. · 2.40 Impact Factor
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Arnon Nagler,
Myriam Labopin,
Avichai Shimoni,
Dietger Niederwieser,
Ghulam J Mufti,
Axel R Zander,
Renate Arnold,
Hildegard Greinix,
Jan J Cornelissen,
Graham H Jackson,
Charles Craddock,
Donald W Bunjes,
Arnold Ganser,
Nigel H Russell,
Slawomira Kyrcz-Krzemien,
Vanderson Rocha,
Mohamad Mohty
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ABSTRACT: Reduced-intensity conditioning allogeneic stem cell transplant (RIC-alloSCT) is being increasingly used for patients with acute myelogenous leukemia (AML) with comorbidities. Few published data are currently available regarding for the use of peripheral blood stem cells (PBSCs) compared to bone marrow (BM) in the RIC-alloSCT using unrelated donors (URDs). This retrospective report compared the outcomes of PBSC versus BM RIC-alloSCT. Between 2000 and 2007, 602 patients with AML in complete remission (CR) underwent RIC-alloSCT from URDs with PBSC (508) or BM (94) grafts. Recipient's age was higher in the PBSC versus BM groups 57 (range, 17-77 years) and 51 (range, 17-76 years), respectively (P < .0001). Leukemia features and disease status at RIC-alloSCT were also comparable between the PBSC versus BM groups. Engraftment was achieved in 97% and 96% with BM versus peripheral blood (PB), respectively. Acute graft-versus-host disease (aGVHD) grade >II was significantly higher in the PBSC group: 27% versus 12% in the BM group (P < .002). Similarly, chronic graft-versus-host disease (cGVHD; at 2 years) was somewhat higher in the PBSC group with 43% ± 3% versus 35% ± 6% in the BM group, respectively (P = .04). The 2-year probabilities of leukemia-free survival (LFS) were 46% ± 3% for the PBSC group in comparison to 43% ± 6% for the BM transplant group (P = NS), whereas relapse incidence was significantly higher in the BM versus the PB transplant group: 46% ± 6% versus 32% ± 3%, respectively (P = .014). Non-relapse mortality (NRM) was significantly higher for the PBSC versus the BM group: 28% ± 2% versus 13% ± 4%, respectively (P = .004). In multivariate analysis, after adjustment for differences between both groups, the PBSC group was associated with a higher incidence of aGVHD (grade II-IV; hazard ratio [HR] = 2.33; P = .06), higher NRM (HR = 2.3; P = .015), and a decreased relapse incidence (HR, 0.61; P = .02) with no statistical difference of LFS between the 2 groups (P = .88). In conclusion, our results indicate significantly higher incidence of aGVHD and NRM and a lower incidence of relapse but not statistically different LFS comparing unrelated PBSC to BM grafts after RIC-alloSCT.
Biology of blood and marrow transplantation: journal of the American Society for Blood and Marrow Transplantation 03/2012; 18(9):1422-9. · 3.15 Impact Factor
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Orly Shimony, Arnon Nagler,
Yechiel N Gellman,
Efrat Refaeli,
Nir Rosenblum,
Lora Eshkar-Sebban,
Ronit Yerushalmi,
Avichai Shimoni,
Simon D Lytton,
Anfisa Stanevsky,
Reuven Or,
David Naor
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ABSTRACT: We show here that the anti-T lymphocyte immunoglobulin (ATG) can induce Treg cells following 24-h incubation in human peripheral blood mononuclear cells (PBMCs). The ATG-induced Treg cells express known cell surface markers (e.g., CD25, FoxP3) and suppress the proliferation of autologous responder PBMCs, stimulated with allogeneic PBMCs, when added into the mixed lymphocyte culture (MLC) at zero time point or 48 h later. We expanded the characteristics of the ATG-induced human Treg cells by showing that they express a novel biomarker designated "activated CD44". ATG-induced Treg cells retain their suppressor function after freezing and thawing or irradiation. Suppression of MLC by ATG-induced Treg cells is consistently seen when the Treg cells and the responder cells were derived from the same donor, but not when they derived from different donors. Finally, patients undergoing stem cell transplantation and conditioned with ATG generate in vivo Treg cells that suppress MLC.
Journal of Clinical Immunology 02/2012; 32(1):173-88. · 3.08 Impact Factor
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ABSTRACT: Multiple Myeloma (MM) is a lymphatic neoplasm characterized by clonal proliferation of malignant plasma cell that eventually develops resistance to chemotherapy. Drug resistance, differentiation block and increased survival of the MM tumor cells result from high genomic instability. Chromosomal translocations, the most common genomic alterations in MM, lead to dysregulation of cyclin D, a regulatory protein that governs the activation of key cell cycle regulator--cyclin dependent kinase (CDK). Genomic instability was reported to be affected by over expression of another CDK regulator--cyclin E (CCNE). This occurs early in tumorigenesis in various lymphatic malignancies including CLL, NHL and HL. We therefore sought to investigate the role of cyclin E in MM. CCNE1 expression was found to be heterogeneous in various MM cell lines (hMMCLs). Incubation of hMMCLs with seliciclib, a selective CDK-inhibitor, results in apoptosis which is accompanied by down regulation of MCL1 and p27. Ectopic over expression of CCNE1 resulted in reduced sensitivity of the MM tumor cells in comparison to the paternal cell line, whereas CCNE1 silencing with siRNA increased the cell sensitivity to seliciclib. Adhesion to FN of hMMCLs was prevented by seliciclib, eliminating adhesion-mediated drug resistance of MM cells. Combination of seliciclib with flavopiridol effectively reduced CCNE1 and CCND1 protein levels, increased subG1 apoptotic fraction and promoted MM cell death in BMSCs co-culture conditions, therefore over-coming stroma-mediated protection. We suggest that seliciclib may be considered as essential component of modern anti MM drug combination therapy.
PLoS ONE 01/2012; 7(4):e33856. · 4.09 Impact Factor
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ABSTRACT: Stroma cells and extracellular matrix (ECM) components provide the pivotal microenvironment for tumor development. The study aimed to evaluate the importance of the pancreatic stroma for tumor development.
Pancreatic tumor cells were implanted subcutaneously into green fluorescent protein transgenic mice, and stroma cells invading the tumors were identified through immunohistochemistry. Inhibition of tumor invasion by stroma cells was achieved with halofuginone, an inhibitor of TGFβ/Smad3 signaling, alone or in combination with chemotherapy. The origin of tumor ECM was evaluated with species-specific collagen I antibodies and in situ hybridization of collagen α1(I) gene. Pancreatic fibrosis was induced by cerulean injection and tumors by spleen injection of pancreatic tumor cells.
Inhibition of stroma cell infiltration and reduction of tumor ECM levels by halofuginone inhibited development of tumors derived from mouse and human pancreatic cancer cells. Halofuginone reduced the number only of stroma myofibroblasts expressing both contractile and collagen biosynthesis markers. Both stroma myofibroblasts and tumor cells generated ECM that contributes to tumor growth. Combination of treatments that inhibit stroma cell infiltration, cause apoptosis of myofibroblasts and inhibit Smad3 phosphorylation, with chemotherapy that increases tumor-cell apoptosis without affecting Smad3 phosphorylation was more efficacious than either treatment alone. More tumors developed in fibrotic than in normal pancreas, and prevention of tissue fibrosis greatly reduced tumor development.
The utmost importance of tissue fibrosis and of stroma cells for tumor development presents potential new therapy targets, suggesting combination therapy against stroma and neoplastic cells as a treatment of choice.
PLoS ONE 01/2012; 7(7):e41833. · 4.09 Impact Factor
