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M Aglietta

Publications and source records attributed to M Aglietta.

At least 55 records · Page 3Linked to original sources
PubMed1996

The effects of human FLT3 ligand on in vitro human megakaryocytopoiesis.

The human homolog of the murine flt3/flk2 gene product is a tyrosine kinase receptor that plays a role in regulating the proliferation and differentiation of cells in the hematopoietic system. Using a plasma-clot clonal assay and a long-term bone marrow culture (LTBMC) system, we studied the effects of the recently cloned human flt3 ligand (FL) alone and in combination with granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-3 (IL-3), or stem cell factor (c-kit ligand [KL]) on human megakaryocytopoiesis. The effects of FL on the primitive megakaryocyte (MK) progenitor cell, the burst-forming unit-megakaryocyte (BFU-MK), and the more differentiated colony-forming unit-megakaryocyte (CFU-MK) were determined. FL alone had no megakaryocytic colony-stimulating activity (MK-CSA), but was capable of augmenting the MK-CSA of both GM-CSF and IL-3. FL synergized with IL-3 at the level of both CFU-MK and BFU-MK and with GM-CSF and KL at the level of CFU-MK. Although FL alone exhibited a limited potential in sustaining long-term megakaryocytopoiesis in vitro, it synergistically augmented the ability of IL-3 and KL, alone or in association, to promote long-term megakaryocytopoiesis. These data indicate that multiple cytokines are necessary to optimally stimulate the proliferation of both classes of MK progenitor cells and that FL plays a significant role in this process by amplifying the MK-CSA of GM-CSF, IL-3, and KL.

Bone Marrow Cells↗
PubMed1996

Expression of type III receptor tyrosine kinases FLT3 and KIT and responses to their ligands by acute myeloid leukemia blasts.

The stem cell tyrosine kinase 1 (STK1) protein is the human homologue of the murine FLT3 gene product, a receptor belonging to the FMS/KIT family. FLT3 and KIT with their ligands control the growth and differentiation of early human hemopoietic cells. In the present study, 16 cases of acute myeloid leukemia (AML) were examined by flow cytometry for cell surface expression of FLT3 and KIT receptors. All cases were also tested for their proliferative response to human FLT3 ligand (FL) and KIT ligand (KL) and for colony formation in the presence of single or associated cytokines. Among 16 AML cases tested, 10/16 expressed FLT3 receptor and 12/16 expressed KIT receptor, without any correlation with FAB subtype. FL and KL stimulated the proliferation of leukemic blasts in 11/16 AML cases (including five FLT3 or KIT receptor-negative cases), with an additive effect when added simultaneously. By contrast, some receptor-expressing AMLs did not display significant proliferative responses to their respective ligands. FL and KL as single factors induced or significantly increased the colony formation by clonogenic precursor cells respectively in eight and six of 13 cases tested. In some cases growth factor association significantly enhanced colony growth. Taken together these observations provide evidence that the pattern of FLT3 and KIT receptor expression is extremely variable among the AMLs and that receptor presence is not necessarily combined with proliferative and clonogenic response or vice versa.

Blast Crisis↗
PubMed1995

Effects of human FLT3 ligand on myeloid leukemia cell growth: heterogeneity in response and synergy with other hematopoietic growth factors.

A novel hematopoietic growth factor for primitive hematopoietic progenitor cells, the ligand for the flt3/flk2 receptor, (FL), has been recently purified and its gene has been cloned. In the present study, we investigated the effects of FL on the proliferation and differentiation of normal and leukemic myeloid progenitor cells. We demonstrate that FL is a potent stimulator of the in vitro growth of granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-3 (IL-3), or G-CSF-dependent granulocyte-macrophage committed precursors from Lin- CD34+ bone marrow cells of normal donors. By contrast, FL does not affect the growth of erythroid-committed progenitors even in the presence of erythropoietin. The effect of FL on the proliferation and on the in vitro growth of clonogenic leukemic precursor cells was studied in 54 acute myeloid leukemia (AML) cases. Fresh leukemia blasts from 36 of 45 patients with AML significantly responded to FL without any relation to the French-American-British (FAB) subtype. FL stimulated the proliferation of leukemic blasts in a dose-dependent fashion. Synergistic activities were seen when FL was combined with G-CSF, GM-CSF, IL-3, or stem cell factor (SCF). FL as a single factor induced or increased significantly colony formation by clonogenic precursor cells from 21 of 24 patients with AML. In the presence of suboptimal and optimal concentrations of G-CSF, GM-CSF, IL3, SCF, or a combination of all factors, FL strongly enhanced the number of leukemic colonies (up to 18-fold). We also evaluated the induction of tyrosine phosphorylated protein on FL stimulation in fresh AML cells. We demonstrate that, on FL stimulation, a band of phosphorylated protein(s) of about 90 kD can be detected in FL-responsive, but not in FL-unresponsive cases. This study suggests that FL may be an important factor for the growth of myeloid leukemia cells, either as a direct stimulus or as a synergistic factor with other cytokines.

Cell Division↗
PubMed1995

A comparison of two GM-CSF schedules to counteract the granulo-monocytopenia of carboplatin-etoposide chemotherapy.

In order to obtain the beneficial effects from granulocyte-macrophage colony-stimulating factor (GM-CSF) on granulo-monocyte recovery with the minimum dose and toxicity, we compared the effect of two different GM-CSF schedules (5 micrograms/kg/day subcutaneously, days 5 to > 18 versus days 12 to > 18 on the cytopenias which follow cytostatic treatment with carboplatin (400 mg/m2 intravenous (i.v.) day 1) and etoposide (100 mg/m2 i.v. days 1 to > 3). 13 patients entered the study for a total of 36 evaluable cycles. The cytostatic treatment produced a neutropenia that persisted for up to day 22 (absolute neutrophil count (ANC) < 1000/microliters in 25% and ANC < 2000 in 50% of control cycles). Early GM-CSF administration markedly increased the leucocyte nadir and produced two waves of leucocytosis: an early one, linked to marrow reserve release and presumably of no value to the patients; and a delayed one, due to marrow precursor and progenitor cell proliferation, in which the granulomonocytosis was associated with a marked eosinophilia. The delayed GM-CSF administration markedly increased the leucocyte nadir and accelerated granulo-monocyte recovery (with an only modest eosinophilia), so that chemotherapy could be repeated every 21 days in all the patients.

Adult↗
PubMed1995

Assessment of interferon cardiotoxicity with quantitative radionuclide angiocardiography.

Three different types of cardiovascular sequelae attributed to interferon therapy have been reported: arrhythmia, ischaemic heart disease and cardiomyopathy. We evaluated the left ventricular ejection fraction (LVEF) during alpha interferon therapy (3 MU administered subcutaneously three times a week for 6 months) in 11 patients with chronic viral hepatitis. LVEF was within the normal range in all patients (mean value +/- SD 64.6 +/- 10.7%) before interferon was started, but decreased after 1 month of therapy (mean value +/- SD 59.7 +/- 8.3%) (P = 0.015). An LVEF reduction of more than 10% was observed in five of the 11 patients. Three months after therapy was stopped, nine of the 11 patients showed an LVEF close to the pre-treatment level (mean value +/- SD 62.1 +/- 8.3%). In our patients with chronic C hepatitis, low subcutaneous doses of interferon alpha often decreased the LVEF. It is not clear whether this finding is due to the direct effect of interferon on cardiac cells, or to the peripheral vascular effects of the drug. As LVEF reduction could be critical in patients with previously reduced myocardial contractility, our results further highlight the need for careful cardiac analysis before starting interferon therapy.

Adult↗
PubMed1995

Platelet activating factor produced in vitro by Kaposi's sarcoma cells induces and sustains in vivo angiogenesis.

Imbalance in the network of soluble mediators may play a pivotal role in the pathogenesis of Kaposi's sarcoma (KS). In this study, we demonstrated that KS cells grown in vitro produced and in part released platelet activating factor (PAF), a powerful lipid mediator of inflammation and cell-to-cell communication. IL-1, TNF, and thrombin enhanced the synthesis of PAF. PAF receptor mRNA and specific, high affinity binding site for PAF were present in KS cells. Nanomolar concentration of PAF stimulated the chemotaxis and chemokinesis of KS cells, endothelial cells, and vascular smooth muscle cells. The migration response to PAF was inhibited by WEB 2170, a hetrazepinoic PAF receptor antagonist. Because neoangiogenesis is essential for the growth and progression of KS and since PAF can activate vascular endothelial cells, we examined the potential role of PAF as an instrumental mediator of angiogenesis associated with KS. Conditioned medium (CM) from KS cells (KS-CM) or KS cells themselves induced angiogenesis and macrophage recruitment in a murine model in which Matrigel was injected subcutaneously. These effects were inhibited by treating mice with WEB 2170. Synthetic PAF or natural PAF extracted from plasma of patients with classical KS also induced angiogenesis, which in turn was inhibited by WEB 2170. The action of PAF was amplified by expression of other angiogenic factors and chemokines: these included basic and acidic fibroblast growth factor, placental growth factor, vascular endothelial growth factor and its specific receptor flk-1, hepatocyte growth factor, KC, and macrophage inflammatory protein-2. Treatment with WEB 2170 abolished the expression of the transcripts of these molecules within Matrigel containing KS-CM. These results indicate that PAF may cooperate with other angiogenic molecules and chemokines in inducing vascular development in KS.

Aged↗
PubMed1995

In vivo effect of human granulocyte-macrophage colony-stimulating factor (GM-CSF) on neutrophil GM-CSF receptors.

The effect of in vivo administration of recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) on neutrophils GM-CSF receptor, was investigated in patients with neoplastic diseases and normal hematopoiesis. Patients were divided into two groups. Group A received a single dose of rhGM-CSF (5 micrograms/kg/day) and receptor studies were performed 90 min and 48 h after treatment. Group B received three doses, administered subcutaneously every 24 h and receptor studies were performed 90 min after first injection and 24 h after the last. Before treatment neutrophils only displayed high-affinity receptors (KD 85 +/- 53 pM; number of receptors/cell 1318 +/- 567). The first injection of rhGM-CSF produced a transient leucopenia and the internalization of GM-CSF receptor on neutrophils in both groups of patients: 90 min after s.c. administration receptors could not be detected with conventional binding studies. In group A patients, 48 h after a single dose of rhGM-CSF, receptors, albeit with a decreased affinity (KD = 240 +/- 131 pM; number of receptors/cell 783 +/- 494) were again expressed. In group B patients, 24 h after the last rhGM-CSF injection, low intermediate affinity receptors not present before treatment appeared (KD 720 +/- 175 pM; number of receptor/cell 1222 +/- 179). They were associated with a low number of high affinity receptors (KD = 9 +/- 4 pM; number of receptors/cell 106 +/- 44). These observations indicate that more than one type of GM-CSF receptor may exist on neutrophils. It may be suggested that in vivo the regulation of the GM-CSF receptor is different from that in vitro and is related to the presence of the cytokine in patient blood.

Dose-Response Relationship, Drug↗
PubMed1995

Blood cell redistribution in the lung after administration of recombinant human granulocyte-macrophage colony-stimulating factor.

Granulocyte-macrophage colony-stimulating factor (GM-CSF), in addition to being a haematopoietic growth factor, has been shown to stimulate in vitro the production of interleukins 1, 6 and 8 (IL-1, IL-6 and IL-8), tumour necrosis factor-alpha (TNF-alpha) and GM-CSF by polymorphonuclear cells (PMNs), alveolar macrophages (AMs), fibroblasts and endothelial cells of the lung, and the growth and differentiation of resident alveolar macrophages. The aim of this study was to establish whether recombinant GM-CSF (rhGM-CSF), administered subcutaneously at a dose of 5 micrograms.kg-1 for 3 days in five patients with unresectable non-small cell lung cancer before starting chemotherapy, induces an increase in the alveolar cell count, and whether these cellular lung variations may be related to increases in the above-mentioned cytokines. In the bronchoalveolar lavage fluid (BALF) total cell count, polymorphonuclear cells, neutrophils, and alveolar macrophages increased significantly in comparison with the baseline, and the extent of variation of the BAL cell count was considerably greater than that of the circulating leucocytes. The mean levels of all the cytokines increased, but a significant difference with respect to the basal condition was observed only for IL-6 and IL-8. After rhGM-CSF treatment, significant correlations were found between neutrophil counts and the levels of IL-6 and IL-8. In conclusion, rhGM-CSF administration induces a cellular expansion in the lung, and the neutrophil increase appears to be related to increased levels of IL-8.

Aged↗
PubMed1994

Human endothelial cells are targets for platelet-activating factor (PAF). Activation of alpha and beta protein kinase C isozymes in endothelial cells stimulated by PAF.

We evaluated the role of the protein kinase C (PKC) and its isozymes in the activation of human endothelial cells (EC) stimulated by platelet-activating factor (PAF). Exposure of confluent EC to PAF resulted in a rapid and concentration-dependent redistribution of PKC from cytosol to plasma-membrane, rearrangement of cytoskeleton (i.e. decrease in F-actin content and redistribution of vinculin), and finally increase in the transendothelial flux of 125I-albumin. Stimulation of EC with oleylacetylglycerol or phorbol 12-myristate 13-acetate induced the modification of the cytoskeletal structures and the increase of 125I-albumin clearance. Inhibitors of PKC prevented the effects induced by PAF on the cytoskeleton and on the barrier function of the EC monolayer. Confluent EC expressed only alpha, beta, and epsilon PKC isoforms. Biochemical and immunochemical analysis showed that the time course of the PKC isozymes translocation from cytosol to the membrane fraction of EC stimulated by PAF was different: beta isoform was redistributed more quickly than alpha isoform. PAF did not induce translocation of PKC epsilon. These results suggest that activation of PKC alpha and beta is an important signal transduction pathway by which PAF activates endothelial monolayer and modify its function of barrier to macromolecules.

Actins↗
PubMed1994

Involvement of a serine protease in the synthesis of platelet-activating factor by endothelial cells stimulated by tumor necrosis factor-alpha or interleukin-1 alpha.

It has been shown that production of platelet-activating factor (PAF, 1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine) by endothelial cells (EC) stimulated with tumor necrosis factor (TNF)-alpha and interleukin (IL)-1 alpha requires the synthesis of new proteins and is regulated by anti-proteinases. Here, we demonstrate that TNF-alpha and IL-1 alpha induce the expression by EC of a 34-kDa diisopropyl fluorophosphate-binding protein immunoprecipitated by an anti-human elastase antibody. This protein is released in the medium and cleaves the chromogenic substrate N-methoxysuccinyl- Ala-Ala-Pro-Val p-anilide, which is specific for elastase. The generation of this elastase-like protein seems to be important for the synthesis of PAF induced by TNF-alpha and IL-1 alpha, as suggested by the following observations: (a) it precedes the synthesis of PAF; (b) the inhibitors of serine protease and anti-human elastase antibody prevent the synthesis of PAF and the activation of 1-O-alkyl-2-lyso-glycerophosphocholine acetyl-CoA: acetyltransferase, which is a key enzyme of the PAF remodelling pathway; (c) elastase, at concentrations similar to that detectable in the medium of cytokine-activated EC, elicits a rapid synthesis of PAF by EC. High-performance liquid chromatography-tandem mass spectrometric analysis of bioactive PAF demonstrates that the molecular species produced after stimulation of EC with TNF-alpha, IL-1 alpha or elastase are similar, with a predominant synthesis of the alkyl species. These results indicate that TNF-alpha and IL-1 alpha stimulate the production of a serine protease which is critical in the activation of enzymes involved in PAF synthesis, suggesting the potential involvement of this mechanism in the regulation of EC functions.

Acetyltransferases↗
PubMed1993

Short-term administration of granulocyte-macrophage colony stimulating factor decreases hematopoietic toxicity of cytostatic drugs.

BACKGROUND: Administration of granulocyte-macrophage colony stimulating factor (GM-CSF) is followed by a rapid increase in the proliferative activity of the hematopoietic precursors. Within 72 hours after its suspension, however, establishment of a negative feedback results in a reduction of the proliferative activity of the hyperplastic marrow to values below the baseline, suggesting refractoriness of hematopoietic progenitors to the action of cell-cycle-specific cytostatic agents. METHODS: The hypothesis that short treatment with GM-CSF before chemotherapy could reduce the hematopoietic toxicity of cytostatics was investigated by administering GM-CSF glycosylate (Sandoz, Basel, Switzerland/Schering-Plough, Kenilworth, NJ) subcutaneously with a 5.5 micrograms/kg protein dosage per day from day-6-day-4 before each course of adjuvant chemotherapy (cyclophosphamide, epirubicin, 5-fluorouracil/cyclophosphamide, methotrexate, 5-fluorouracil alternate) in patients with node-positive breast cancer. Twelve patients were randomized to receive GM-CSF before chemotherapy or only at chemotherapy. The hematologic picture and dose intensity of chemotherapy were compared in the two groups of patients. RESULTS: In the group of patients receiving chemotherapy only, 22% of the cycles had to be postponed because of leukopenia, with a consequent reduction of the dose intensity, whereas in the GM-CSF group, the neutrophil counts remained at significantly (P < 0.001) higher levels, and there were no delays in chemotherapy administration. No substantial systemic toxicity was associated with this brief GM-CSF schedule. Moreover, GM-CSF treatment did not result in delayed depletion of the hematopoietic pool. CONCLUSIONS: Short treatment with GM-CSF can enable the dose intensity of conventional protocols of proven efficacy to be increased.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1993

Interleukin-3 in vivo: kinetic of response of target cells.

Human recombinant interleukin-3 (IL-3; Sandoz AG, Basel, Switzerland) was administered for 7 days to patients with neoplastic disease and normal hematopoiesis. The purpose of the study was to assess IL-3 toxicity, to identify target cells, to define their kinetics of response at different dose levels, and to determine if IL-3 in vivo increased the sensitivity of bone marrow (BM) progenitors to the action of other hematopoietic growth factors. A total of 21 patients entered the study; the dosage ranged from 0.25 to 10 micrograms/kg/d. The effect on peripheral blood cells during treatment showed no significant changes in the number of platelets, erythrocytes, neutrophils, or lymphocytes (and their subsets). A mild monocytosis and basophilia occurred. Eosinopenia, present in the first hours of treatment, was followed by a dose-and time-dependent eosinophilia. IL-3 treatment affected BM cell proliferation by increasing the percentage of BM progenitors engaged in the S-phase of the cell cycle. The effect was dose dependent, with the various progenitors showing different degrees of sensitivity. The most sensitive progenitors were the megakaryocyte progenitors (colony-forming unit-megakaryocyte), then the erythroid progenitors (burst-forming unit-erythroid), and finally the granulo-monocyte progenitors (colony-forming unit-granulocyte-macrophage) whose proliferative activity was stimulated at the higher doses of IL-3. Only a slight increase in the proliferative activity of myeloblasts, promyelocytes, and myelocytes was observed, whereas the activity of erythroblasts was unchanged. The priming effect was such that BM progenitors, purified from patients treated with IL-3, produced more colonies in vitro in the presence of granulocyte colony-stimulating factor (G-CSF; granulocyte colonies), IL-5 (eosinophil colonies), and granulocyte-macrophage CSF (GM-CSF; predominantly eosinophil colonies). These data indicate that even in vivo IL-3 acts essentially as a primer for the action of other cytokines. Therefore, optimum stimulus of myelopoiesis will require either endogenous or exogenous late-acting cytokines such as G-CSF, erythropoietin, GM-CSF, and IL-6 for achieving fully mature cells in peripheral blood. If exogenous cytokines are used with IL-3, it is likely that G-CSF will yield more neutrophils, whereas GM-CSF may enhance eosinophils, monocytes, and neutrophils. Attention to the clinical relevance of each cell type will be necessary and should determine the selection of the combination of cytokines.

Adult↗
PubMed1993

Granulocyte-macrophage colony stimulating factor and interleukin 3: target cells and kinetics of response in vivo.

Granulocyte-macrophage colony stimulating factor (GM-CSF) and interleukin 3 (IL-3) target cells have been studied in vivo in subjects with normal hemopoiesis. GM-CSF administration elicits a rapid and sustained neutrophilia, monocytosis and eosinophilia due to a direct proliferative stimulus on all progenitors and precursors of the granulomonopoietic lineage. GM-CSF is also a powerful stimulator of erythroid burst forming unit (BFU-E) and megakaryocyte colony forming unit (CFU-MK) proliferation. Its action, however, does not extend to more mature erythroid and megakaryocyte cells suggesting the need for combined treatment with lineage-specific growth factors such as erythropoietin (Epo) or IL-6 to obtain a complete myeloid stimulation. When GM-CSF is discontinued, its action rapidly vanishes, and a rapid decline in the proliferative rate of target cells to values below the initial ones occurs. The potential clinical usefulness of this phenomenon in regard to cancer chemotherapy is discussed. IL-3 treatment induces only a rapid and marked eosinophilia. Chronic IL-3 administration, however, increases the proliferation of all myelopoietic progenitors and primes CFU-GM to become more sensitive in vitro to the action of granulocyte CSF (G-CSF), GM-CSF and IL-5. Whereas an increased IL-5 sensitivity seems devoid of therapeutic potential, the priming of G-CSF and GM-CSF action suggests rational scheduling for a combined treatment of IL-3 with other hemopoietic growth factors.

Animals↗
PubMed1993

High-dose sequential (HDS) chemotherapy with blood and marrow cell autograft as salvage treatment in very poor prognosis, relapsed non-Hodgkin's lymphoma.

We tested the feasibility and efficacy of a novel high-dose sequential chemoradiotherapy programme (HDS) in 14 relapsed or refractory non-Hodgkin's lymphoma patients with very poor prognostic features, i.e. transformed histology, marrow invasion, low performance status. This regimen included the sequential administration of high-dose cyclophosphamide (CY) 7 g/m2 followed by high-dose methotrexate (MTX) 8 g/m2 and high-dose VP16 2 g/m2 and finally by total body irradiation (TBI)-melphalan and autograft of bone marrow and peripheral blood progenitor cells. No hemopoietic growth factor support was employed in any phase. There was one treatment-related death during the high-dose phase; three other patients did not complete the programme. All 10 patients concluding the programme achieved complete remission, with four patients in complete clinical remission at a median follow up of 34 months. Median overall survival was 27 months and median failure-free survival (FFS) was 12 months. Twenty-six well comparable patients received conventional salvage therapy during the same period. Their projected median overall survival (8 months) and median FFS (4 months) were shorter than in the HDS group (p = 0.06 for overall survival and p = 0.03 for FFS). Thus, HDS is a feasible programme and may offer superior results than conventional therapy in poor-prognosis NHL patients.

Adult↗