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Biomedical subjects

W Oster

Publications and source records attributed to W Oster.

At least 55 records · Page 3Linked to original sources
PubMed1990

Hematopoietic growth factors in oncology.

Hematopoietic growth factors, or hemopoietins, are peptide hormones produced by peripheral blood cells, bone marrow stroma, as well as several other cell types, such as endothelial cells and fibroblasts. Hemopoietins play a central role in regulating peripheral blood cell number and function. By recombinant DNA technology, several of these factors, also called colony-stimulating factors (CSF) or interleukins, are now available in such quantities to allow clinical evaluation. First experiences in clinical trials show that these peptides are capable of stimulating production of various cell types of the peripheral blood by stimulation of bone marrow progenitor cells without significant toxicity for the patient under treatment. Treatment of renal anemia by erythropoietin and reduction of chemotherapy-induced myelosuppression by G- and GM-CSF are already defined indications for these hemopoietins. Further studies are under way to test the indication of these factors in other clinical situations as well as studies investigating the biology, pharmacology, and clinical efficacy of interleukin 3 (IL-3).

Hematopoietic Cell Growth Factors↗
PubMed1989

Production of macrophage-, granulocyte-, granulocyte-macrophage- and multi-colony-stimulating factor by peripheral blood cells.

The specific cell sources and signals for induction of various colony-stimulating factors (CSF) in peripheral blood mononuclear cells (PBMC), purified T lymphocyte and monocyte (Mo) populations have been investigated. In the absence of exogenous activating stimuli, human PBMC, T cells and Mo failed to produce stable cytoplasmic mRNA for CSF for macrophages (M-CSF or CSF-1), for granulocytes (G-CSF), for granulocytes and macrophages (GM-CSF) and for multilineage CSF [multi-CSF, interleukin (IL) 3] and thus failed to release CSF proteins. However, after stimulation with phorbol myristate acetate and phytohemagglutinin, M-, G-, GM- and multi-CSF mRNA became detectable in PBMC, resulting in the secretion of the respective proteins. Identical culture conditions resulted in synthesis of only G- and M-CSF by purified Mo, whereas purified T lymphocytes produced GM-CSF and multi-CSF only. When Mo or T lymphocytes were exposed to recombinant human interferon-gamma or were stimulated by triggering the epitopes recognized by the monoclonal antibodies anti-Tll2 and Tll3, respectively, again disparate CSF expression patterns were found to be associated with both cell species. Moreover, IL2-receptive T lymphocytes showed the same distinct pattern of CSF secretion when activated by recombinant human IL2.

Colony-Stimulating Factors↗
PubMed1989

Role of colony-stimulating factors in the biology of acute myelogenous leukemia.

A high proportion of acute myeloid leukemias (AML) recently investigated for their capacity to synthesize biologically active bioregulatory molecules was found to accumulate messenger (m) RNA and to produce membrane-bound or -secreted forms of stimulating factors for granulocyte, macrophage and mixed granulocyte-macrophage colony growth. Blast cells have also been found to secrete interleukin 1, tumor necrosis factor-alpha, interleukin 6, and to express receptors for various growth factors as well. However, growth factors like interleukin 2 and interleukin 3 have not been identified as AML products, and several other factors including interleukin 4, interleukin 5, etc. need further evaluation. Responsiveness of clonogenic leukemic cells to exogenous growth-promoting factors in vitro suggests a possible role of these biomolecules in the course of these disorders. Important evidence for the crucial role of growth factors, at least in some subtypes of AML, has been provided by demonstrating constitutive growth factor production by leukemic cells and their autonomous in vitro growth which is dependent on autocrine secretion of a specific growth factor. The concert of mechanisms providing stimulatory and inhibitory signals for hematopoiesis, which is adapted to the various physiological requirements of the organism, may have multiple defects in AML. This leads to successive steps of malfunctioning of cells, which finally express a fully malignant phenotype. In addition, these derangements also lead to defects in accessory cells on the level of mediator communication. However, there is evidence for autonomous growth promotion of AML blast by constitutive production of growth factors active in an autocrine fashion (GM-CSF, G-CSF, interleukin 6) and by recruitment of accessory cells to increase CSF supply (GM-CSF, G-CSF) via molecules such as interleukin 1 and TNF-alpha in a paracrine fashion. Molecular analysis of transformed hematopoietic cells has revealed changes of the genome, e.g., insertion of viral genetic information or cytogenetic fractures at DNA sites controlling growth factor gene activation. These events appear to be crucial in the induction of uncontrolled growth factor expression promoting oncogenic transformation of hematopoietic progenitor cells.

Colony-Stimulating Factors↗
PubMed1989

Minimal peripheral blood cells carrying clonal markers of B cell disorders: evidence for monoclonality of circulating lymphocytes in patients with multiple myeloma.

Peripheral blood lymphocytes (PBL) of 20 patients with multiple myeloma (MM) were assayed for clonality by Southern blot and cell surface marker analysis. Eight samples showed monoclonal origin of circulating lymphocytes by demonstrating rearrangements of the heavy chain immunoglobulin gene (IgH). In selected experiments, comparison of IgH rearrangements of bone marrow plasma cells and peripheral blood-derived mononuclear cells, highly enriched for B lymphocytes, proved to be identical. However, monoclonal circulating cells could not be detected in samples with rearranged IgH genes by surface marker phenotyping using one-color immunofluorescence analysis and a panel of monoclonal and polyclonal antibodies to various B lineage-associated antigens. These results indicate that in a substantial proportion of MM, monoclonal growth involves circulating B lymphocytes and underscores the clinical usefulness of Southern analysis of IgH gene rearrangements for monitoring this disease.

Antibodies, Monoclonal↗
PubMed1989

A phase-II study of low-dose cyclophosphamide and recombinant human interleukin-2 in metastatic renal cell carcinoma and malignant melanoma.

Recent preclinical and clinical studies that have demonstrated antitumor activity of high-dose recombinant interleukin-2 (rIL-2), and animal models that demonstrated a synergistic effect of low-dose cyclophosphamide, led us to study rIL-2 (Cetus Corp., Emeryville, Calif) in a phase II clinical trial in combination with low-dose cyclophosphamide in 32 patients, 18 with malignant melanoma and 14 with renal cell carcinoma. rIL-2 was given once daily at 3 x 10(6) U/m2, as a 30-min infusion for 14 days in cycle I and for 2 x 5 days in cycles II and III respectively; if tolerated, the dose was increased to a maximum of 6 x 10(6) U m-2 day-1; the cycles, separated by 1 week treatment-free intervals, were preceded each by a single i.v. bolus of cyclophosphamide at 350 mg/m2. The most prominent side-effects encountered in this trial consisted of a capillary leak syndrome, myalgia and fever that required dose reduction during the first cycle in one-half of the patients. Given the limit of tolerable toxicities in a standard care unit, the regimen employed achieved minor antitumor activity. No remission was achieved in patients with renal cell carcinoma, and 15% of melanoma patients showed objective responses (partial response + minor response).

Adult↗
PubMed1989

Lymphokine activated killer cells.

Various subpopulations of human leukocytes may be induced by lymphokines to exert cytotoxic activity. In man major histocompatibility complex non-restricted tumor cell lysis by interleukin-2 (IL-2) induced peripheral blood lymphocytes is attributed mainly to natural killer cells. These T cell receptor negative large granular lymphocytes are called lymphokine activated killer (LAK) cells. In order to explore the potential of LAK cells in tumor therapy, several clinical studies have been conducted, using IL-2 alone or in combination with ex vivo IL-2-activated peripheral blood lymphocytes. Objective responses have reproducibly been achieved only in renal cell carcinoma and malignant melanoma and were associated with considerable toxicity. In view of restricted efficacy and increasing doubts as to whether LAK cells indeed account for the in vivo observed responses, more recent strategies focus on tumor antigen specific cytotoxic T cells or tumor infiltrating lymphocytes. Successful translation of this approach into clinical practice, however, may be dependent on some basic problems of tumor immunology to be solved which were thought to be by-passed by the LAK cell approach.

Animals↗
PubMed1989

A multicenter trial of interleukin-2 and low-dose cyclophosphamide in highly chemotherapy-resistant malignancies.

The anti-tumor activity of high-dose recombinant interleukin-2 (IL-2) has been demonstrated in several recent preclinical and clinical studies. In an attempt to study possible synergistic effects with low-dose cyclophosphamide (CYC), a phase II clinical trial was initiated in 32 patients, 18 with malignant melanoma (MM) and 14 with renal cell carcinoma (RCC). The recombinant IL-2 (Cetus Corp., Emeryville, Ca, U.S.A.) was given once daily at 3 x 10(6) U/m2, as a 30-min infusion for 14 days in cycle I and for five days twice in cycles II and III, respectively; if tolerated, the dose was escalated to a maximum of 6 x 10(6) U/m2/day; the cycles, separated by 1-week treatment-free intervals, were each preceded by a single i.v. bolus of CYC at 350 mg/m2. The most prominent side-effects encountered in this trial consisted of a capillary leak syndrome, myalgia and fever requiring dose reduction in half of the patients during the first cycle. Given the limit of tolerable toxicities in a standard care unit, the regimen employed achieved minor anti-tumor activity. No objective responses were achieved in patients with RCC and a 15% remission rate (PR + MR) was seen in melanoma patients.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1989

Granulocyte-macrophage colony-stimulating factor induces cytokine secretion by human polymorphonuclear leukocytes.

Granulocyte-macrophage colony-stimulating factor (GM-CSF) is known as an inducer of proliferation and functional activation of myeloid cells. This study was carried out to characterize the effects of GM-CSF on polymorphonuclear leukocytes (PMN) more extensively. Using Northern blot analysis, we show that PMN are able to accumulate mRNAs for different cytokines, including tumor necrosis factor-alpha (TNF-alpha); G-CSF, and M-CSF, all of which are involved in inflammation and hematopoiesis. Biological assays and immunoassays demonstrate that PMN translate these mRNAs, except TNF-alpha, into secretory proteins. However, the expression of these cytokines is dependent on stimulation by exogenous signals, preferentially provided by the T cell-derived lymphokine GM-CSF. Stimulation of hematopoiesis and amplification of defense mechanisms after T cell activation thus might involve not only monocytes but also PMN, a cell type previously believed to be biosynthetically inactive.

Animals↗
PubMed1989

Participation of the cytokines interleukin 6, tumor necrosis factor-alpha, and interleukin 1-beta secreted by acute myelogenous leukemia blasts in autocrine and paracrine leukemia growth control.

Autonomous in vitro growth of myeloid leukemic colony-forming cells may in part result from autocrine production of colony-stimulating factors (CSF). Some acute myeloid leukemia (AML) samples, however, fail to synthesize CSF despite growing autonomously in agar, and are therefore believed to bypass CSF requirements. Cytokines such as IL-6, tumor necrosis factor (TNF)-alpha, and IL-1, products of cells of the myeloid lineage, are known to be involved in growth control of myeloid progenitor cells. Since these molecules may also contribute to autocrine and paracrine growth regulation of myeloid leukemias, we screened a series of AML for cytokine production. In addition, possible roles of IL-6, TNF-alpha, and IL-1 in growth control of AML were investigated in vitro. We show that a substantial proportion of AML cells produce IL-6, TNF-alpha, and IL-1-beta and use these mediators to stimulate their growth by disparate mechanisms: IL-6 acts as a costimulator to enhance CSF-induced clonogenicity of AML blasts. TNF-alpha induces CSF production by endothelial cells and may therefore provide a paracrine loop to support leukemia growth.

Colony-Stimulating Factors↗
PubMed1989

Hematopoietic responses in patients with advanced malignancy treated with recombinant human granulocyte-macrophage colony-stimulating factor.

The in vivo effect of yeast-derived recombinant human granulocyte-macrophage colony-stimulating factor (rh GM-CSF) was investigated in 30 patients with advanced malignancy in a phase Ib trial. Patients were treated at four different dose levels (120 to 1,000 micrograms/m2/d) by either daily intravenous (IV) bolus injection or 24-hour continuous infusion. Administration of rh GM-CSF resulted in a broad spectrum of dose- and schedule-dependent hematopoietic effects. Sustained infusion of rh GM-CSF elicited a maximum 17-fold average peak increase of the total WBC count with mainly neutrophils, eosinophils, and monocytes accounting for this rise, and increases in bone marrow cellularity with a shift to immature myeloid elements. Elevation of lymphocytes, platelets, and reticulocytes was not induced. Within five days after discontinuation of treatment the leukocytosis had disappeared. Adverse reactions encountered with rh GM-CSF seen in 65% of the patients studied were never life-threatening and always rapidly reversible. They included mild myalgias, facial flushing, low-grade fever, headache, bone discomfort, nausea, dyspnea, and transient decline of platelet counts. These results suggest that rh GM-CSF can be safely administered at the doses and schedules used and that it can induce in vivo some of the biological effects reported in in vitro studies. Although no objective antitumour responses have been seen, the ability of rh GM-CSF to increase number and function of leukocytes in vivo may prevent neutropenia and infections when GM-CSF is added to cytotoxic cancer therapy.

Adolescent↗
PubMed1989

Interleukin-4 induces secretion of CSF for granulocytes and CSF for macrophages by peripheral blood monocytes.

T cells are known to interact cooperatively with monocytes to produce Colony-Stimulating Factors (CSF), although T cell-mediated signals leading to CSF secretion by monocytes are not completely understood. We have made use of Northern blot hybridization and specific bioassays to study the effects of the T cell product interleukin-4 (IL-4) on monocyte CSF expression. The results suggest a previously unrecognized role of IL-4 as a CSF inducer since exposure of monocytes to IL-4 resulted in accumulation of transcripts for granulocyte-CSF (G-CSF) and macrophage-CSF (M-CSF). Consequently, IL-4-activated monocytes released factors in their culture supernatants biologically and antigenically indistinguishable from G- and M-CSF.

Animals↗
PubMed1989

Hematologic effects of recombinant human granulocyte colony-stimulating factor in patients with malignancy.

The effect of recombinant human granulocyte colony-stimulating factor (G-CSF) on hematologic parameters was evaluated in a phase I clinical study in 18 patients with advanced malignancy. G-CSF was administered once daily as a 30-minute infusion for 14 days; three patients each were treated at increasing dose levels of 1, 3, 10, 30, and 60 micrograms kg-1 day-1. A transient decrease in neutrophil and monocyte counts was observed immediately after the G-CSF infusion, followed by a dose-dependent increase of up to 15-fold. G-CSF-induced neutrophils exhibited an increased O2- radical production, and serum levels of enzymes related to granulocyte turnover, including lysozyme and elastase, were markedly elevated during therapy. A dose-dependent depression of platelet counts occurred in the second third of the treatment course, followed by a spontaneous recovery despite continuing therapy. G-CSF was well-tolerated; minor to moderate bone pain was the most common side effect. The primary course of the malignant diseases studied was not significantly altered. G-CSF appears to be an appropriate means to selectively increase the number of functionally competent polymorphonuclear phagocytes.

Adult↗
PubMed1989

Granulocyte-macrophage colony-stimulating factor (CSF) and multilineage CSF recruit human monocytes to express granulocyte CSF.

We assessed the capacity of recombinant human granulocyte-macrophage colony-stimulating factor (GM-CSF) and multilineage (Multi)-CSF to induce release of granulocyte-CSF (G-CSF) by highly purified peripheral blood monocyte (Mo) preparations. Our results reveal that GM-CSF and Multi-CSF, either alone or in a synergistic concert, activate Mo to transcribe G-CSF messenger (m) RNA and release biologically active G-CSF protein into their culture supernatants. G-CSF had no regulatory effect on Mo expression of cytoplasmic G-CSF mRNA levels and G-CSF protein secretion by itself. These differential actions of CSFs provide further insight into self-regulatory mechanisms within the growth factor hierarchy system.

Cell-Free System↗
PubMed1989

High-level secretion of tumor necrosis factor-alpha contributes to hematopoietic failure in hairy cell leukemia.

Hairy cell leukemia (HCL) is frequently associated with severe pancytopenia. The authors detected high levels of tumor necrosis factor (TNF)-alpha in the bone marrow serum of patients with HCL and found anti-TNF-alpha neutralizing monoclonal antibodies (MoAbs) to be able to enhance hematopoiesis of HCL patients in in vitro colony assays. As potent producers of TNF-alpha, hairy cells could be identified, thus implicating the malignant population in the pathogenesis of hematopoietic failure due to inappropriate secretion of this cytokine.

Hematopoietic System↗
PubMed1988

Granulocyte/macrophage colony-stimulating factor induces interleukin 1 production by human polymorphonuclear neutrophils.

The purpose of this study was to determine whether human polymorphonuclear neutrophils (PMN), which share a common cell lineage with macrophages, could produce factors such as IL-1. We show by Northern blot analysis and bioassays that PMN can be induced to accumulate mRNA specific for IL-1 alpha and IL-1 beta indistinguishable in size from IL-1 mRNA synthesized by activated human macrophages and consequently to release IL-1-like activity in their culture supernatants, that could be neutralized by a mAb to IL-1. The granulocyte-macrophage colony-stimulating factor was identified as a major physiologic inducer for PMN-IL-1.

Animals↗
PubMed1988

Recombinant human granulocyte-macrophage colony-stimulating factor induces secretion of autoinhibitory monokines by U-937 cells.

Colony-stimulating factors are required for survival proliferation, differentiation and functional activation of granulocytes, macrophages and their precursor cells. In the present report, however, we demonstrate antiproliferative activity of recombinant human (rh) granulocyte-macrophage colony-stimulating factor (GM-CSF) on monoblast cell line U-937 and provide evidence for the involvement of tumor necrosis factor alpha TNF-alpha and interleukin 1 beta (IL 1 beta) in its growth inhibitory action. GM-CSF (but not granulocyte CSF, G-CSF or macrophage CSF, M-CSF) suppressed DNA synthesis and self renewal of U-937 cells. Similarly, medium conditioned by U-937 cells in response to GM-CSF (GM-CSF U-937-CM) was able to reduce clonogenicity and [3H]thymidine uptake by U-937 cells. Since neutralization of GM-CSF present in GM-CSF U-937-CM by monoclonal antibody to GM-CSF did not abrogate the autoinhibitory activity present in GM-CSF U-937-CM, we considered the possibility that other soluble molecules are released by U-937 cells upon GM-CSF stimulation. Neutralization by antibodies to IL 1 beta and TNF-alpha suggested that both monokines could be the antiproliferative principle operating in GM-CSF U-937-CM. Moreover, employing IL 1 beta-specific enzyme-linked immunosorbent assay, TNF-alpha specific radioimmunoassay, Northern analysis using a cloned TNF-alpha-specific cDNA and an oligonucleotide probe for IL 1 beta, we demonstrate GM-CSF-inducible IL 1 beta and TNF-alpha gene expression by U-937 cells at the mRNA and protein level. Although M-CSF expression was induced under similar conditions, M-CSF failed to inhibit growth of U-937 cells.

Adult↗
PubMed1988

The suppressive effects of recombinant human tumor necrosis factor-alpha on normal and malignant myelopoiesis: synergism with interferon-gamma.

The modulation of growth of normal and leukemic myeloid progenitor cells in soft agar cultures by recombinant human tumor necrosis factor-alpha (TNF alpha) and recombinant human interferon-gamma (IFN gamma) was investigated. TNF alpha inhibited colony formation of all colony types representing different maturational stages of normal progenitor cells committed to the myeloid lineage with different orders of sensitivity. Blast-type colonies derived from patients with acute myelogenous leukemia were more sensitive to TNF alpha inhibition than progenitor cells purified from normal bone marrow or bone marrow from patients with stable-phase chronic myelogenous leukemia. The response of most colony types to IFN gamma was poor. However, when IFN gamma was administered together with TNF alpha, synergistically enhanced antiproliferative effects were detected in all colony types tested. The antiproliferative action of IFN gamma on myelopoiesis was enhanced in culture by the presence of autologous monocytes, presumedly by inducing endogenous production of TNF alpha. However, TNF alpha seemed to act directly on the progenitor cells themselves to suppress their clonal growth, rather than involving accessory marrow elements such as monocytes and/or T lymphocytes.

Antibodies, Monoclonal↗