bluuebunny/crossref_metadata_2025_split huggingface dataset:
Activation of the MAP kinase pathway by c-Kit is PI-3 kinase dependent in hematopoietic progenitor/stem cell lines
Authors: Wandzioch Ewa , Edling Charlotte E. , Palmer Ruth H. , Carlsson Leif , Hallberg Bengt 
Published: March 2004

AbstractThe Steel factor (SF) and its receptor c-Kit play a critical role for various cell types at different levels in the hematopoietic hierarchy. Whether similar or distinct signaling pathways are used upon c-Kit activation in different cell types within the hematopoietic hierarchy is not known. To study c-Kit signaling pathways in the hematopoietic system we have compared c-Kit downstream signaling events in SF-dependent hematopoietic stem cell (HSC)–like cell lines to those of mast cells. Both Erk and protein kinase B (PKB)/Akt are activated by ligand-induced activation of the c-Kit receptor in the HSC-like cell lines. Surprisingly, phosphoinositide-3 (PI-3) kinase inhibitors block not only PKB/Akt activation but also activation of Raf and Erk. SF-induced activation of Ras is not affected by inhibition of PI-3 kinase. In mast cells and other more committed hematopoietic precursors, the activation of Erk by SF is not PI-3 kinase dependent. Our results suggest that a molecular signaling switch occurs during differentiation in the hematopoietic system whereby immature hematopoietic progenitor/stem cells use a PI-3 kinase–sensitive pathway in the activation of both Erk and PKB/Akt, which is then switched upon differentiation to the more commonly described PI-3 kinase–independent mitogen-activated protein (MAP) kinase pathway.
Impaired natural and CD16-mediated NK cell cytotoxicity in patients with WAS and XLT: ability of IL-2 to correct NK cell functional defect
Authors: Gismondi Angela , Cifaldi Loredana , Mazza Cinzia , Giliani Silvia , Parolini Silvia , Morrone Stefania , Jacobelli Jordan , Bandiera Elisabetta , Notarangelo Luigi , Santoni Angela 
Published: March 2004

AbstractIn this study we show that Wiskott-Aldrich syndrome protein (WASp), a critical regulator of actin cytoskeleton that belongs to the Scar/WAVE family, plays a crucial role in the control of natural killer (NK) cell cytotoxicity. Analysis of NK cell numbers and cytotoxic activity in patients carrying different mutations in the WASP coding gene indicated that although the percentage of NK cells was normal or increased, natural cytotoxicity and antibody-mediated NK cell cytotoxicity were inhibited in all patients with the classical WAS phenotype and in most patients carrying mutations associated with the X-linked thrombocytopenia (XLT) phenotype. The inhibition of NK cell-mediated cytotoxicity was associated with the reduced ability of WAS and XLT NK cells to form conjugates with susceptible target cells and to accumulate F-actin on binding. Treatment with interleukin-2 (IL-2) corrected the functional defects of NK cells by affecting their ability to bind to sensitive target cells and to accumulate F-actin. In addition, we provide information on the molecular mechanisms that control WASp function, demonstrating that binding of NK cells to sensitive targets or triggering through CD16 by means of reverse antibody-dependent cellular cytotoxicity (ADCC) rapidly activates Cdc42. We also found that WASp undergoes tyrosine phosphorylation upon CD16 or β2-integrin engagement on NK cells. (Blood. 2004;104:436-443)
VEGF receptor phosphorylation status and apoptosis is modulated by a green tea component, epigallocatechin-3-gallate (EGCG), in B-cell chronic lymphocytic leukemia
Authors: Lee Yean K. , Bone Nancy D. , Strege Ann K. , Shanafelt Tait D. , Jelinek Diane F. , Kay Neil E. 
Published: March 2004

AbstractWe recently reported that chronic lymphocytic leukemia (CLL) cells synthesize and release vascular endothelial growth factor (VEGF) under normoxic and hypoxic conditions. CLL B cells also express VEGF membrane receptors (VEGF-R1 and VEGF-R2), suggesting that they use VEGF as a survival factor. To assess the mechanism of apoptosis resistance related to VEGF, we determined the impact of VEGF on CLL B cells, and we studied the impact of epigallocatechin-3-gallate (EGCG), a known receptor tyrosine kinase (RTK) inhibitor, on VEGF receptor status and viability of CLL B cells. VEGF165 significantly increased apoptotic resistance of CLL B cells, and immunoblotting revealed that VEGF-R1 and VEGF-R2 are spontaneously phosphorylated on CLL B cells. EGCG significantly increased apoptosis/cell death in 8 of 10 CLL samples measured by annexin V/propidium iodide (PI) staining. The increase in annexin V/PI staining was accompanied by caspase-3 activation and poly–adenosine diphosphate ribose polymerase (PARP) cleavage at low concentrations of EGCG (3 μg/mL). Moreover, EGCG suppressed the proteins B-cell leukemia/lymphoma-2 protein (Bcl-2), X-linked inhibitor of apoptosis protein (XIAP), and myeloid cell leukemia-1 (Mcl-1) in CLL B cells. Finally, EGCG (3-25 μg/mL) suppressed VEGF-R1 and VEGF-R2 phosphorylation, albeit incompletely. Thus, these results suggest that VEGF signaling regulates survival signals in CLL cells and that interruption of this autocrine pathway results in caspase activation and subsequent leukemic cell death.
Value of sequential monitoring of left ventricular ejection fraction in the management of thalassemia major
Authors: Davis Bernard A. , O'Sullivan Caoimhe , Jarritt Peter H. , Porter John B. 
Published: March 2004

Abstract
Regular monitoring of left ventricular ejection fraction (LVEF) for thalassemia major is widely practiced, but its informativeness for iron chelation treatment is unclear. Eighty-one patients with thalassemia major but no history of cardiac disease underwent quantitative annual LVEF monitoring by radionuclide ventriculography for a median of 6.0 years (interquartile range, 2-12 years). Intraobserver and interobserver reproducibility for LVEF determination were both less than 3%. LVEF values before and after transfusion did not differ, and exercise stress testing did not reliably expose underlying cardiomyopathy. An absolute LVEF of less than 45% or a decrease of more than 10 percentage units was significantly associated with subsequent development of symptomatic cardiac disease (P &lt; .001) and death (P = .001), with a median interval between the first abnormal LVEF findings and the development of symptomatic heart disease of 3.5 years, allowing time for intervention. In 34 patients in whom LVEF was less than 45% or decreased by more than 10 percentage units, intensified chelation therapy was recommended (21 with subcutaneous and 13 with intravenous deferoxamine). All 27 patients who complied with intensification survived, whereas the 7 who did not comply died (P &lt; .0001). The Kaplan-Meier estimate of survival beyond 40 years of age for all 81 patients is 83%. Sequential quantitative monitoring of LVEF is valuable for assessing cardiac risk and for identifying patients with thalassemia major who require intensified chelation therapy.
T-cell lymphoma as a model for the use of histone deacetylase inhibitors in cancer therapy: impact of depsipeptide on molecular markers, therapeutic targets, and mechanisms of resistance
Authors: Piekarz Richard L. , Robey Robert W. , Zhan Zhirong , Kayastha Ganesh , Sayah Anousheh , Abdeldaim Amina H. , Torrico Sonia , Bates Susan E. 
Published: March 2004

AbstractDepsipeptide (FK228) is a novel histone deacetylase inhibitor currently in clinical trials and the first to demonstrate clinical activity in patients. Responses have been observed in patients with T-cell lymphomas, despite prior treatment with multiple chemotherapeutic agents. To better understand the effects of histone deacetylase inhibitors on T-cell lymphoma, the human T-cell lymphoma cell line HUT78 was tested for sensitivity and molecular response to depsipeptide. Treatment with depsipeptide, as well as other histone deacetylase inhibitors, caused induction of histone acetylation, induction of p21 expression, and substantial apoptosis without significant cell cycle arrest. Treatment with the caspase inhibitor z-VAD-fmk significantly inhibited depsipeptide-induced apoptosis, enabling detection of cell cycle arrest. Treatment with depsipeptide increased expression of the interleukin-2 (IL-2) receptor, and combination with the IL-2 toxin conjugate denileukin diftitox resulted in more than additive toxicity. Cells selected for resistance to depsipeptide overexpressed the multidrug resistance pump, P-glycoprotein (Pgp). However, cells selected for resistance to depsipeptide in the presence of a Pgp inhibitor had a Pgp-independent mechanism of resistance. These studies confirm the activity of depsipeptide in a T-cell lymphoma model and suggest a general sensitivity of T-cell lymphoma to histone deacetylase inhibitors, an emerging new class of anticancer agents. (Blood. 2004;103:4636-4643)
Homeostatic chemokines drive migration of malignant B cells in patients with non-Hodgkin lymphomas
Authors: Trentin Livio , Cabrelle Anna , Facco Monica , Carollo Davide , Miorin Marta , Tosoni Alicia , Pizzo Paola , Binotto Gianni , Nicolardi Linda , Zambello Renato , Adami Fausto , Agostini Carlo , Semenzato Gianpietro 
Published: March 2004

AbstractThis study investigated the role of several chemokines and their receptors on malignant B lymphocytes recovered from 13 patients with chronic lymphocytic leukemia (CLL), 9 with hairy cell leukemia (HCL), 5 with mantle cell lymphoma (MCL), 5 with marginal zone B-cell lymphoma (MZL), 6 with small lymphocytic lymphoma (SLL), and 5 with follicular cell lymphoma (FCL). Flow cytometry analysis demonstrated that CXCR4 and CXCR5 were expressed on all malignant and normal B cells. Considering CC receptors, CCR1 was expressed in 70% of patients with CLL and 40% of those with HCL but was lacking in patients with MCL, MZL, SLL, and normal B cells. CCR2 showed a heterogeneous pattern of expression. CCR3 was found in almost all patients with CLL and in the majority of those with HCL, whereas it was usually lacking in patients with MZL and SLL and in healthy subjects. CCR5 was expressed in patients with HCL and MCL. Migration assays showed that different chemokines, mainly CXCL12 and CXCL13, are able to trigger migration of malignant B lymphocytes. Some of these chemokines induce calcium mobilization. These data indicate that different patterns of chemokine receptor expression identify different malignant B-cell subsets and that these receptors are functional and might play a role in malignant B-cell circulation. (Blood. 2004;104:502-508)
The pu.1 promoter drives myeloid gene expression in zebrafish
Authors: Hsu Karl , Traver David , Kutok Jeffery L. , Hagen Andreas , Liu Ting-Xi , Paw Barry H. , Rhodes Jennifer , Berman Jason N. , Zon Leonard I. , Kanki John P. , Look A. Thomas 
Published: March 2004

AbstractPU.1 is a member of the Ets family of transcription factors and plays an essential role in the development of both myeloid and lymphoid cells. To examine zebrafish pu.1 (zpu.1) expression in subpopulations of blood cells during zebrafish development, we linked a 9-kb zebrafish genomic fragment upstream of the zpu.1 initiator codon to green fluorescent protein (GFP) and microinjected this construct to generate stable transgenic lines. GFP-positive fluorescent myeloid precursors were observed migrating from the anterolateral mesoderm in living embryos from 16 to 28 hours after fertilization (hpf) in a pattern that overlaps the expression pattern of endogenous zpu.1 mRNA. Analysis of larval histologic sections revealed GFP-expressing hematopoietic cells in the developing zebrafish kidney. Flow cytometric analysis of cells from adult whole kidney marrow revealed 2 discrete subpopulations of GFP-positive cells, which after cell sorting exhibited either myeloid or early lymphoid morphology. Thus, the zebrafish zpu.1 promoter fragment used here is capable of driving reporter gene expression in subsets of embryonic and adult hematopoietic cells. These transgenic lines will be useful to dissect the cellular and molecular control of myeloid cell differentiation, and this promoter fragment may prove useful in the development of zebrafish models of acute myeloid leukemia.
Anemia, thrombocytopenia, leukocytosis, extramedullary hematopoiesis, and impaired progenitor function in Pten+/-SHIP-/- mice: a novel model of myelodysplasia
Authors: Moody Jennifer L. , Xu Lixin , Helgason Cheryl D. , Jirik Frank R. 
Published: March 2004

Abstract
The myeloproliferative disorder of mice lacking the Src homology 2 (SH2)-containing 5′ phosphoinositol phosphatase, SHIP, underscores the need for closely regulating phosphatidylinositol 3-kinase (PI3K) pathway activity, and hence levels of phosphatidylinositol species during hematopoiesis. The role of the 3′ phosphoinositol phosphatase Pten in this process is less clear, as its absence leads to embryonic lethality. Despite Pten heterozygosity being associated with a lymphoproliferative disorder, we found no evidence of a hematopoietic defect in Pten+/- mice. Since SHIP shares the same substrate (PIP3) with Pten, we hypothesized that the former might compensate for Pten haploinsufficiency in the marrow. Thus, we examined the effect of Pten heterozygosity in SHIP-/- mice, predicting that further dysregulation of PIP3 metabolism would exacerbate the pheno-type of the latter. Indeed, compared with SHIP-/- mice, Pten+/-SHIP-/- animals developed a myelodysplastic phenotype characterized by increased hepatosplenomegaly, extramedullary hematopoiesis, anemia, and thrombocytopenia. Consistent with a marrow defect, clonogenic assays demonstrated reductions in committed myeloid and megakaryocytic progenitors in these animals. Providing further evidence of a Pten+/-SHIP-/- progenitor abnormality, reconstitution of irradiated mice with marrows from these mice led to a marked defect in short-term repopulation of peripheral blood by donor cells. These studies suggest that the regulation of the levels and/or ratios of PI3K-derived phosphoinositol species by these 2 phosphatases is critical to normal hematopoiesis. (Blood. 2004;103:4503-4510)
Phase 1 trial of a novel anti-CD20 fusion protein in pretargeted radioimmunotherapy for B-cell non-Hodgkin lymphoma
Authors: Forero Andres , Weiden Paul L. , Vose Julie M. , Knox Susan J. , LoBuglio Albert F. , Hankins Jordan , Goris Michael L. , Picozzi Vincent J. , Axworthy Don B. , Breitz Hazel B. , Sims Robert B. , Ghalie Richard G. , Shen Sui , Meredith Ruby F. 
Published: March 2004

Abstract
Pretargeted radioimmunotherapy (PRIT) has the potential to increase the dose of radionuclide delivered to tumors while limiting radiation to normal tissues. The purpose of this phase 1 trial is to assess safety of this multistep approach using a novel tetrameric single-chain anti-CD20–streptavidin fusion protein (B9E9FP) as the targeting moiety in patients with B-cell non-Hodgkin lymphoma (NHL), and to characterize its pharmacokinetics and immunogenicity. All patients received B9E9FP (160 mg/m2 or 320 mg/m2); either 48 or 72 hours later, a synthetic clearing agent (sCA) was administered (45 mg/m2) to remove circulating unbound B9E9FP. 90Yttrium (90Y; 15 mCi/m2)/111In (5 mCi)–DOTA-biotin was injected 24 hours later. There were 15 patients enrolled in the study. B9E9FP had a mean plasma half-life (T½) of 25 ± 6 hours with a reduction in plasma level of more than 95% within 6 hours of sCA administration. 90Y/111In-DOTA-biotin infusion resulted in rapid tumor localization and urinary excretion. The ratio of average tumor to whole-body radiation dose was 49:1. No significant hematologic toxicities were noted in 12 patients. There were 2 patients who had hematologic toxicity related to progressive disease. There were 2 complete remissions (90 and 325 days) and one partial response (297 days). B9E9FP performs well as the targeting component of PRIT with encouraging dosimetry, safety, and efficacy. A dose escalation trial of 90Y-DOTA-biotin in this format is warranted.
Induction of megakaryocytopoiesis and thrombocytopoiesis by JTZ-132, a novel small molecule with thrombopoietin mimetic activities
Authors: Inagaki Koji , Oda Tomohiro , Naka Yuichi , Shinkai Hisashi , Komatsu Norio , Iwamura Hiroyuki 
Published: March 2004

Abstract
We report in this paper that a novel small molecule, JTZ-132, induced growth and differentiation of megakaryocytic progenitor cells and improved thrombocytopenia in myelosuppressed mice. JTZ-132 stimulated proliferation of UT-7/TPO cells, a cell line highly sensitive to thrombopoietin (TPO), and exhibited full efficacy comparable to TPO with an approximate EC50 (median effective concentration) value of 0.43 μM, whereas little proliferation was observed in a TPO-insensitive cell line, UT-7/EPO, and human carcinoma cell line, HCT116. Signal transduction studies revealed that JTZ-132 induced tyrosine phosphorylation of c-Mpl, Janus kinase-2 (JAK2), and signal transducers and activators of transcription 5 (STAT5) in UT-7/TPO cells as well as TPO. JTZ-132 increased the number of megakaryocyte-specific marker, CD61+ and CD41+, cells in cultures of mouse and human bone marrow cells, respectively, and the colonyforming unit megakaryocytes in mouse bone marrow cells. In vivo experiments in x-ray irradiation– or busulfan injection–induced myelosuppressed mice demonstrated that subcutaneously injected JTZ-132 at 30 mg/kg showed significantly higher platelet number at nadir and accelerated platelet recovery without affecting white blood cell number. These data suggest that JTZ-132 is a novel stimulator of megakaryocytopoiesis and thrombocytopoiesis in vitro and in vivo with TPO mimetic activities and that it is useful for the treatment of thrombocytopenia.
CD40 activation of BCP-ALL cells generates IL-10–producing, IL-12–defective APCs that induce allogeneic T-cell anergy
Authors: D'Amico Giovanna , Vulcano Marisa , Bugarin Cristina , Bianchi Giancarlo , Pirovano Gisella , Bonamino Martin , Marin Virna , Allavena Paola , Biagi Ettore , Biondi Andrea 
Published: March 2004

AbstractThe use of leukemia cells as antigen-presenting cells (APCs) in immunotherapy is critically dependent on their capacity to initiate and sustain an antitumor-specific immune response. Previous studies suggested that pediatric B-cell precursor acute lymphoblastic leukemia (BCP-ALL) cells could be manipulated in vitro through the CD40-CD40L pathway to increase their immunostimulatory capacity. We extended the APC characterization of CD40L-activated BCP-ALL for their potential use in immunotherapy in a series of 19 patients. Engaging CD40 induced the up-regulation of CCR7 in 7 of 11 patients and then the migration to CCL19 in 2 of 5 patients. As accessory cells, CD40L-activated BCP-ALL induced a strong proliferation response of naive T lymphocytes. Leukemia cells, however, were unable to sustain proliferation over time, and T cells eventually became anergic. After CD40-activation, BCP-ALL cells released substantial amounts of interleukin-10 (IL-10) but were unable to produce bioactive IL-12 or to polarize TH1 effectors. Interestingly, adding exogenous IL-12 induced the generation of interferon-γ (IFN-γ)–secreting TH1 effectors and reverted the anergic profile in a secondary response. Therefore, engaging CD40 on BCP-ALL cells is insufficient for the acquisition of full functional properties of immunostimulatory APCs. These results suggest caution against the potential use of CD40L-activated BCP-ALL cells as agents for immunotherapy unless additional stimuli, such as IL-12, are provided.
Selective B-cell depletion with rituximab for the treatment of patients with acquired hemophilia
Authors: Stasi Roberto , Brunetti Maurizio , Stipa Elisa , Amadori Sergio 
Published: March 2004

Abstract
The activity and safety profile of selective B-cell depletion with rituximab, an anti-CD20 monoclonal antibody, were evaluated in 10 patients with acquired hemophilia. Rituximab was given intravenously at the dose of 375 mg/m2 once weekly for 4 consecutive weeks. Infusion-related side effects were observed in 3 patients but were of mild intensity and did not require discontinuation of treatment. Eight patients with Factor VIII (FVIII) inhibitor titers between 4 and 96 Bethesda units per milliliter (BU/mL) achieved a complete remission, which was defined as a return to normal FVIII activity and undetectable FVIII inhibitor titers. Two more patients with inhibitor levels greater than 100 BU/mL experienced only a partial transient decrease of the inhibitor after rituximab alone, but they achieved a complete response after being challenged with a combination of rituximab plus pulse intravenous cyclophosphamide. With a median follow-up of 28.5 months (range, 12-41 months), 3 patients have thus far relapsed. Retreatment with the monoclonal antibody at the same dose and schedule resulted in a new sustained response in all these patients. In conclusion, rituximab appears an effective and well-tolerated treatment for patients with acquired hemophilia and low inhibitor titers. A reinforcement of therapy with other agents seems to be required to achieve a full and durable response in those patients with high inhibitor levels. (Blood. 2004;103:4424-4428)
An anti-CD19 antibody inhibits the interaction between P-glycoprotein (P-gp) and CD19, causes P-gp to translocate out of lipid rafts, and chemosensitizes a multidrug-resistant (MDR) lymphoma cell line
Authors: Ghetie Maria-Ana , Marches Radu , Kufert Stephanie , Vitetta Ellen S. 
Published: March 2004

AbstractWe have previously demonstrated that an anti-CD19 monoclonal antibody (MAb; HD37) inhibits the function of the P-glycoprotein (P-gp) pump in a multidrug-resistant (MDR) B-lymphoma cell line, Namalwa/MDR1, and that this effect is not due to the recognition of a cross-reactive epitope on P-gp. In this study, we have used the same cell line to define the mechanisms responsible for the effect of HD37 on the P-gp pump. Using fluorescence resonance energy transfer (FRET), we show that CD19 and P-gp are constitutively associated in cells. In the absence of treatment with anti-CD19, 40% of P-gp molecules expressed by Namalwa/MDR1 cells reside in the low-density lipid (ie, cholesterol-rich) microdomains (lipid rafts). Following treatment of the cells with HD37 and disruption of the interactions between P-gp and CD19, P-gp translocated out of lipid rafts and CD19 translocated into lipid rafts. The effect of chemosensitization on Namalwa/MDR1 cells was specific for CD19; an anti-CD22 MAb had no such effect, although the cells express CD22. These results suggest that anti-CD19 might chemosensitize P-gp+ cells by interfering with interactions between CD19 and P-gp, rapidly resulting in the translocation of P-gp into a compartment on the plasma membrane where it is no longer active.