A double-blind placebo-controlled study with granulocyte-macrophage colony-stimulating factor during chemotherapy for ovarian carcinoma

In a placebo-controlled double-blind dose-finding trial, 15 patients with ovarian cancer stage III or IV received daily s.c. 1.5, 3, or 6 micrograms/kg recombinant human granulocyte-macrophage colony-stimulating factor (GM-CSF). At each dose step three patients received recombinant human GM-CSF, and two received placebo. Chemotherapy comprised 6 cycles of carboplatin, 300 mg/m2, and cyclophosphamide, 750 mg/m2, by i.v. bolus on day 1 every 4 weeks. GM-CSF, given on days 6-12 on an outpatient basis, raised the mean leukocyte count on days 7, 10, and 15 and the mean neutrophil count on days 7 and 10 at all dose levels as compared with the control group. Neutrophil counts of less than 0.5 x 10(9)/liter occurred in 20 of 22 cycles in the control group and in 5 of 17 cycles at the 6-micrograms/kg/day GM-CSF dose level (P less than 0.0005). In comparison with the control group, the mean eosinophil count was higher on days 10 and 15 at all GM-CSF doses, as was the mean monocyte count on day 15. The mean platelet count was raised at the 3- and 6-micrograms GM-CSF doses on days 15 and 22. Chemotherapy dose reduction or postponement due to myelotoxicity occurred in 9 of 28 cycles in the placebo groups versus 5 of 44 cycles in the GM-CSF group (not significant). Local skin infiltrates at the GM-CSF injection sites occurred in 8/9 patients, leading to premature removal of two patients from the study. Capillary leakage of 131I-albumin was increased in all patients 5 days after the first chemotherapy course but was not significantly affected by 4 days of GM-CSF treatment. Tumor necrosis factor alpha and C-reactive protein serum levels increased during GM-CSF administration at the 6-micrograms dose level, but interleukin 6 serum levels were not affected. We conclude that a dose of 3 and 6 micrograms/kg/day GM-CSF reduces the severity of neutropenia and thrombocytopenia after carboplatin-cyclophosphamide. This GM-CSF dose does not induce additional capillary leakage.

The effects of five hematopoietic growth factors on human small cell lung carcinoma cell lines: interleukin 3 enhances the proliferation in one of the eleven cell lines

Eleven small cell lung carcinoma cell lines of human origin were exposed to different colony stimulating factors (CSFs) to study whether CSFs could enhance the spontaneous cell proliferation and modify the action of cytotoxic drugs. In ten cell lines no suppressive or stimulative effect was observed when measured in a [3H]thymidine assay and a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. However, one cell line (GLC-20) could be stimulated by interleukin 3 (IL-3) when measured with a proliferative as well as a clonogenic assay. This enhancing effect was cell concentration dependent in the [3H]thymidine assay. Additional CSFs such as granulocyte-macrophage-CSF, granulocyte-CSF, IL-4, IL-6, insulin, or bombesin could not further augment the IL-3 supported proliferation. In addition, IL-3 binding studies demonstrated the presence of IL-3 receptors on the GLC-20 cells. Two types of receptors were demonstrated by Scatchard analysis: high affinity receptors (59 +/- 4 sites/cell) with a dissociation constant (Kd) of 31 +/- 9 pmol/liter; and low affinity receptors (1915 +/- 91 sites/cell) with a Kd of 2.0 +/- 0.8 nmol/liter. Finally, it was shown that the toxic effects of adriamycin and cisplatin on the proliferation of the GLC-20 cell line could partially be abrogated in the presence of IL-3. These data indicate that in some cases CSFs can modulate the proliferation of small cell lung carcinoma cell lines and interfere with the effects of chemotherapeutic drugs.

The role of colony-stimulating factors in acute leukemia

This article summarises the effects of colony-stimulating factors and related molecules on leukemia blasts by focussing on autocrine and paracrine growth control. This information may lead to a better understanding of the pathobiology of this highly malignant disorder, and may have therapeutic implications.

Interleukin-4 suppresses the interleukin-3 dependent erythroid colony formation from normal human bone marrow cells

Human recombinant interleukin 4 (IL-4) was studied for its effects on the erythroid burst forming unit (BFU-E) from human bone marrow cells. IL-4 alone neither supports nor suppresses the erythropoietin (Epo)-dependent colony formation. Different results were obtained when IL-4 was combined with interleukin-3 (IL-3) in the presence of Epo. IL-4 suppressed the IL-3 supported erythroid colony formation in all cases (an increase of 58 +/- 8% with IL-3 versus an increase of 14 +/- 7% with IL-3 plus IL-4, n = 8). This antagonizing effect was dependent on the continuous presence of IL-4 in the culture medium, but was independent of adherent cells, B-, T-cells, or the presence of serum in the culture medium. Finally, the effects of IL-4 and IL-3 were studied on the 'Epo-independent' BFU-E by adding Epo on day 3. A decline of the IL-3 supported BFU-E was observed in the presence of IL-4 but the degree of reduction was equivalent to the results obtained when Epo was supplied at day 0. These findings indicate that IL-4 acts as suppressive growth factor for the IL-3 supported erythroid colony formation from human bone marrow cells.

Divergent effects of interleukin-4 (IL-4) on the granulocyte colony-stimulating factor and IL-3-supported myeloid colony formation from normal and leukemic bone marrow cells

Human recombinant interleukin-4 (IL-4) was studied for its effects on myeloid progenitor cells from normal and leukemic bone marrow cells in the presence and absence of additional growth factors. IL-4 itself did not support myeloid cluster or colony formation (CFU-GM). However, cultures supplied with IL-4 (300 U/mL) and IL-3 demonstrated a significant decline in myeloid colony numbers (CFU-GM) compared with the effects of IL-3 alone: (48 +/- 27 v 88 +/- 27 CFU-GM/10(5) MNC). In contrast, IL-4 augmented the G-CSF-supported CFU-GM: (80 +/- 31 v 148 +/- 52 CFU-GM/10(5) MNC). The effects of IL-4 were not mediated by accessory cells because similar results were obtained with and without T-cell, B-cell, or adherent depleted cell fractions. Morphologic analysis of clusters (day 7) and the colonies (day 14) demonstrated that IL-4 enhanced myeloid colony formation in the presence of G-CSF, whereas the cultures supplied with IL-3 and IL-4 did not show a lineage-restricted decline of CFU-GM. A heterogeneity in growth response was observed in the leukemic counterpart. With the 3H-thymidine proliferation assay, IL-4 augmented the G-CSF-induced proliferation of acute myeloid leukemic (AML) cells in 4 of the 12 cases, while the IL-3-supported proliferation was antagonized in 3 of the 12 cases. In the blast colony assay, IL-4 suppressed the IL-3-supported AML-CFU in the majority of cases, but enhanced the G-CSF stimulated AML-CFU in 3 of 6 cases. These data demonstrate divergent effects of IL-4 on the normal myeloid progenitor cell in the presence of IL-3 or G-CSF, while a variability in responsiveness is observed in the leukemic counterpart.

Efficacy and tolerability of recombinant human granulocyte-macrophage colony-stimulating factor in patients with chemotherapy-related leukopenia and fever

30 patients with chemotherapy-related leukopenia (white cells 1.0 x 10(9)/l or lower) and fever (temperature 38.5 degrees C or higher) were treated in a double-blind randomised trial with standard antibiotics and 7 days of intravenously administered recombinant human granulocyte-macrophage colony-stimulating factor (GM-CSF, 2.8 micrograms/kg per day) or placebo. GM-CSF administration resulted in a faster percentage increase of peripheral neutrophil count after 2 and 3 days of treatment, except in patients treated with ablative chemotherapy and autologous bone-marrow transplantation. However, GM-CSF did not shorten the period of fever or antibiotic administration. No side-effects were observed; in particular tumour necrosis factor alpha and interleukin-6 did not increase in the 5 GM-CSF patients tested. These data suggest that a subgroup of patients with chemotherapy-related leukopenia and fever may benefit from GM-CSF treatment in view of the observed effects on neutrophil count.

In polycythemia vera human interleukin 3 and granulocyte-macrophage colony-stimulating factor enhance erythroid colony growth in the absence of erythropoietin

To further define the growth factors required for the in vitro proliferation of erythroid progenitors in polycythemia vera (PV), we have compared the ability of interleukin 3 (IL-3) and granulocyte-macrophage colony-stimulating factor (GM-CSF) to support the growth of erythropoietin (Epo)-dependent and -independent erythroid colony formation. By using nonadherent mononuclear cells from peripheral blood, Epo-dependent colony formation was enhanced by IL-3 and GM-CSF in PV patients. Comparable results were obtained with normal erythroid progenitors. Augmenting effects of IL-3 and GM-CSF were observed on spontaneous erythroid colony formation, i.e., erythroid colony formation in the absence of exogenous supplied Epo. This was not due to a small amount of Epo in the culture media because an anti-Epo antibody did not prevent endogenous colony formation, nor did it prevent the enhancing effects of IL-3. Finally it was observed that in contrast to IL-3, monocyte depletion was required for the enhancing effects of GM-CSF on erythroid colony formation. These results provide evidence that endogenous colony formation in PV is independent of Epo but can be augmented by IL-3 or GM-CSF.

Quantitation of plasma levels of tetranectin--effects of oral contraceptives, pregnancy, treatment with L-asparaginase and liver cirrhosis

Tetranectin is a tetrameric protein that binds to kringle 4 of plasminogen. Increase of electrophoretic mobility of the otherwise slowly migrating tetranectin in the presence of ethylenediaminetetraacetate was used to develop a reproducible electroimmunoassay to quantify plasma levels. Plasma levels in normals were found within narrow limits of 100 +/- 16 (SD)%, (100% = 0.15 mumol/l). There was no difference between males and females, smokers and non-smokers, and there were no significant changes with age from 20 to 49 years. Patients with severe liver cirrhosis showed a large variation in plasma tetranectin levels but no systematic or average reduction, in contrast to strong reductions in plasma levels of other proteins. Patients treated with L-asparaginase showed a gradual reduction in time in plasma levels of various proteins, though tetranectin showed no significant reduction. It is concluded that tetranectin can be assayed reproducibly in plasma and has a well regulated plasma level. This level is not sensitive to conditions with reductions in synthesis of many proteins, such as during cirrhosis of the liver and during L-asparaginase therapy. The reductions in plasma levels during the use of oral contraceptives and pregnancy indicate involvement of sex steroids in the metabolism of tetranectin.

Independent regulation of M-CSF and G-CSF gene expression in human monocytes

The macrophage and granulocyte colony-stimulating factors, M-CSF and G-CSF, act in vitro to induce proliferation and differentiation of monocyte and granulocyte progenitor cells, respectively. We show here that both of these CSFs can be produced by stimulated human blood monocytes, but the M-CSF and G-CSF genes are independently regulated. Recombinant human interleukin-3 (IL-3) and GM-CSF primarily induce expression of the M-CSF gene and secretion of M-CSF, whereas bacterial lipopolysaccharide primarily induces expression of the G-CSF gene and secretion of G-CSF. These results suggest that under different conditions of in vitro stimulation the monocyte secretes factors that could lead selectively to either granulocyte or monocyte production.

Expression of the macrophage colony-stimulating factor and c-fms genes in human acute myeloblastic leukemia cells

Macrophage colony-stimulating factor (CSF-1; M-CSF) is a growth factor required for growth and differentiation of mononuclear phagocytes. The effects of CSF-1 are mediated through binding to specific, high-affinity surface receptors encoded by the c-fms gene. CSF-1 and c-fms gene expression was investigated in fresh human acute myeloblastic leukemic cells by Northern blot hybridization using cDNA probes. 4.0-kb CSF-1 transcripts were detected in 10 of 17 cases of acute myeloblastic leukemia (AML), while c-fms transcripts were detected in 7 of 15. Coexpression of CSF-1 and c-fms was observed in five cases, and in five other cases neither gene was expressed. In situ hybridization demonstrated that transcripts for CSF-1 were present in 70-90% of cells in each of three cases studied while c-fms mRNA was detected in 40-70% of cells. The constitutive expression of CSF-1 transcripts was associated with production of CSF-1 protein, although detectable amounts of CSF-1 were not secreted unless the cells were exposed to phorbol ester. These results demonstrate that leukemic myeloblasts from a subset of patients with AML express transcripts for both the CSF-1 and CSF-1 receptor genes, often in the same leukemic cells in vitro.

Human granulocyte-monocyte colony-stimulating factor and interleukin 3 stimulate monocyte cytotoxicity through a tumor necrosis factor-dependent mechanism

Human colony-stimulating factors (CSF) exert multiple effects on the proliferation, differentiation, and function of myeloid lineage cells. In this study, the effects of three recombinant human CSFs (granulocyte-monocyte CSF [GM-CSF], interleukin 3 [IL-3], and granulocyte CSF [G-CSF]) on antibody-independent monocyte tumoricidal activity were investigated by using WEHI 164 fibrosarcoma cells as monocyte-sensitive targets. None of the CSFs directly induced monocyte cytotoxicity, although both GM-CSF and IL-3 were found to significantly enhance monocyte killing in response to a second stimulatory event (endotoxin). No effect was seen with G-CSF. Antitumor necrosis factor antibody completely abolished CSF-enhanced monocyte cytotoxicity, which suggests that this effect was mediated through increased release of tumor necrosis factor (TNF). As previously shown for GM-CSF, IL-3 was found to induce cytoplasmic accumulation of TNF messenger RNA (mRNA) after 18 hours of exposure. These results suggest that GM-CSF and IL-3 may stimulate monocyte killing indirectly by enhancing expression of TNF mRNA, thereby leading to augmented TNF protein secretion in response to a second activation signal.

The biology of acute myeloblastic leukemia

Many questions about the biology of AML remain to be answered. The initial genetic lesions that inhibit differentiation and increase the likelihood of self renewal have yet to be identified. Given the heterogeneity of this neoplasm, it is possible that many different mutational events may be capable of triggering leukemia. Alternatively, there may be only a small number of possible initial leukemic mutations, and the heterogeneous phenotype of the disease is determined by the evolution of different subclones that have acquired different secondary mutations. Studies with retroviral oncogenes have suggested that a common secondary event in an evolving myeloid tumor is the development of growth factor independence by either leukemic cell production of CSF or possibly constitutive activation of a CSF receptor. These mechanisms have not yet been established as important in human AML, although there is intriguing evidence to suggest that CSF genes are inappropriately activated in many cases.

Secretion of interleukin-1 by acute myeloblastic leukemia cells in vitro induces endothelial cells to secrete colony stimulating factors

The interaction of acute myeloblastic leukemia (AML) cells with stromal cells was investigated by adding AML-conditioned media to cultures of human endothelial cells. This conditioned media contained factors that induced expression of both the granulocyte macrophage colony-stimulating factor (GM-CSF) and granulocyte CSF (G-CSF) genes and release of colony stimulating activity from endothelial cells. The conditioned media contained interleukin-1 (IL-1) bioactivity and the endothelial cell stimulatory activity was partially neutralized by anti-IL-1 antiserum. Constitutive expression of the IL-1-beta gene was detected in ten of 17 AML cases analyzed. These results suggest that the unregulated secretion of IL-1 by AML cells can induce stromal cells in vitro to overproduce CSFs. This could contribute to the unrestricted growth of AML cells.

Effects of recombinant IL-3, GM-CSF, and G-CSF on proliferation of leukemic clonogenic cells in short-term and long-term cultures

To further define the growth factors required for the in vitro proliferation of acute myeloblastic leukemic (AML) cells, we have compared the ability of recombinant interleukin-3 (IL-3), granulocyte-macrophage colony stimulating factor (GM-CSF), and granulocyte colony stimulating factor (G-CSF) to support growth of AML colony forming cells (AML-CFU). IL-3, GM-CSF, and G-CSF are active as single growth factors in short-term colony cultures and have additive effects when used in combination in some cases. The effects of these CSFs on the proliferation of AML cells in long-term-cell-suspension cultures were also investigated. These cultures provide an estimate of the "self-renewal" capacity and long-term proliferation potential of AML cells. There was considerably heterogeneity with regard to the effects of individual growth factors, but in general, IL-3, GM-CSF, and G-CSF promoted self-renewal of AML cells, and combinations tended to be more effective in supporting long-term survival of AML-CFU. There was evidence of gradual differentiation, but this was evident in control cells and did not appear to be accelerated by CSF treatment. These results of short-term and long-term cultures indicate that each of the CSFs tested can be used by AML cells to support proliferation. The lack of evidence that the CSFs enhance in vitro differentiation does not suggest they will be valuable as therapeutic differentiation agents.

Lymphocyte subpopulations in peripheral blood and bone marrow in patients with idiopathic myelofibrosis

In 8 patients with idiopathic myelofibrosis (IM) T and B cells were studied in view of the possibility that immunological dysfunctions are involved in initiating or contributing to the bone marrow fibrosis. In peripheral blood the absolute numbers of E-SRBC and OKT3+ lymphocytes were significantly reduced; in addition a significant decline was observed in the proportion and absolute numbers of OKT8+ cells, resulting in a reversed Leu-3a/OKT8 ratio. An impaired B cell function was observed in 4 of the 8 patients, characterized by a disturbed in vitro pokeweed mitogen stimulated immunoglobulin synthesis and low serum immunoglobulin levels. Immuno-histological studies of the bone marrow demonstrated a scarcity of T cells but normal numbers of B cells. However, no correlation was noted between the observed deviations of B and T cells and the degree of bone marrow fibrosis determined by means of bone marrow histology and serum procollagen-III levels. These data are not sufficient to support the hypothesis that immunological changes in IM are primarily involved in the process of bone marrow fibrosis.

Patterns of acute myeloid leukemia colony growth in response to recombinant granulocyte-macrophage colony-stimulating factor (rGM-CSF)

In order to assess the response of acute myeloid leukemia colony-forming cells (AML-CFU) to recombinant granulocyte-macrophage colony-stimulating factor (rGM-CSF), AML blasts of 20 patients were cultured in a colony assay supplemented with titrated concentrations of rGM-CSF. In 16 cases rGM-CSF was able to induce AML colonies. In eight cases maximal clonogenic cell proliferation was obtained with 100 U rGM-CSF/ml alone (type I response). In eight other cases, however, maximal colony numbers were reached only after the addition of low concentrations of PHA-leukocyte conditioned media (PHA-LCM) to the rGM-CSF containing cultures (type II response). These values could not be obtained with higher doses of rGM-CSF (500 U/ml) or PHA-LCM separately. Thus in this subgroup, optimal AML colony formation depended on rGM-CSF plus an additional factor. Finally, in 4 of 20 cases rGM-CSF alone (100 U, 1000 U/ml) was not capable of inducing any AML colonies in vitro (type III). In these latter cases proliferation of AML-CFU could be achieved only by supplementing PHA-LCM. We conclude that GM-CSF is a stimulator of the in vitro proliferation of AML clonogenic cells. However, in a majority of these cases, i.e., 12 out of 20, AML-CFU require an additional factor for optimal proliferation which is produced by PHA-stimulated leukocytes.

The effects of GM-CSF and G-CSF in promoting growth of clonogenic cells in acute myeloblastic leukemia

A small subset of leukemic cells from most patients with acute myeloblastic leukemia (AML) have properties of stem cells and can be assayed by colony formation in agar or methylcellulose. Colony formation generally requires the addition of exogenous growth factors, but the exact factors required are incompletely defined. The AML colony-promoting activities of two recombinant human colony-stimulating factors (GM-CSF and G-CSF) were investigated by using blasts from 48 patients with AML. In nine cases, no colonies formed with either CSF. In seven cases colonies formed only in response to G-CSF and in 11 cases only in response to GM-CSF. In 21 cases colonies formed in response to either GM-CSF or G-CSF, and in 12 of these cases there was an additive effect between the two CSFs in determining maximum colony size. For cases responding to both GM- and G-CSF, the total number of colonies formed in response to the combination of both CSFs was almost always less than additive compared with the number of colonies formed in response to the individual CSFs. Further, the AML-CFU responding to either GM-CSF or G-CSF could not be distinguished by surface markers or by the cytochemical staining pattern of the colonies. These results suggest that there is considerable overlap between the GM-CSF- and G-CSF-responsive AML-CFU subpopulations in most cases. For five of seven cases, the combination of GM-CSF and G-CSF could replace a leukocyte feeder layer in providing maximum growth stimulation. These results indicate that GM-CSF and G-CSF are active growth factors for AML cells and are frequently additive in promoting maximum colony size.

Different repopulation kinetics of erythroid (BFU-E), myeloid (CFU-GM) and T lymphocyte (TL-CFU) progenitor cells after autologous and allogeneic bone marrow transplantation

Marrow recovery of erythroid (BFU-E), myeloid (CFU-GM) and T-lymphocyte (TL-CFU) progenitor cells was studied at various time intervals after autologous bone marrow transplantation in 10 patients with acute myeloid leukaemia in remission. These data were compared with those in 14 recipients of T-cell depleted allogeneic marrow grafts. The results indicate markedly different repopulation kinetics of BFU-E, CFU-GM and TL-CFU after autologous and allogeneic bone marrow transplantation. Following autografting reduced numbers of BFU-E and CFU-GM were always present at 2 months after transplantation. Between 2-6 and 6-24 months a gradual increase occurred, although reduced BFU-E and CFU-GM values were still noted in 50% of the cases in spite of normal bone marrow cellularity and restoration of peripheral blood counts. In contrast, in the allograft recipients normal BFU-E numbers appeared within 2 months after transplantation. In addition, CFU-GM values had become normal in 35% of the tests performed at 1-2 months and respectively in 66% and 100% at 2-6 and 6-24 months. The recovery pattern of TL-CFU differed from that of the other haemopoietic progenitor cells. TL-CFU showed a fast recovery, i.e. within 1 month after autologous bone marrow transplantation which was much more rapid than that of BFU-E and CFU-GM. After allografting, however, TL-CFU regenerated at a slower rate and reached normal levels between 2 and 6 months after transplantation. We suggest that the delayed restoration of myeloid and erythroid progenitor cells after autologous transplantation is related to a proliferative defect of the graft as a result of the preceding cytotoxic chemotherapy, the underlying malignant disease and/or cryopreservation. The slower recovery of the T lymphocyte precursors after allografting might be due to the immunological interactions between graft and host, the immuno-suppressive therapy and/or the in vitro T cell depletion of the graft.

The mutual relationship between the two molecular forms of the major fibrinolysis inhibitor alpha-2-antiplasmin in blood

Alpha-2-antiplasmin, a major inhibitor of fibrinolysis, is synthesized in the liver and occurs in blood in two molecular forms: a very active plasminogen-binding (PB) form and a less active nonplasminogen-binding (NPB) form. This study investigates the origin and mutual relationship of these two forms in vivo and in vitro. Despite wide variation in plasma concentration of the inhibitor (16% to 138%), the ratio between the two forms in vivo was found to be, in the main, constant among healthy volunteers, heterozygotes for a congenital deficiency of alpha-2-antiplasmin, and patients with a stable liver cirrhosis: PB/NPB = 2.41 +/- 0.34 (SD). Resynthesis after depletion or increased synthesis in the acute-phase reaction showed a specific increase of the PB form of the molecule in blood after discontinuation of L-asparaginase or streptokinase therapy and after myocardial infarction. In vitro studies demonstrated that only the PB form was present after one day in the culture medium of the human cell line Hep G2, while the NPB form appeared after 11 days. Clearance after inhibition of synthesis by L-asparaginase therapy revealed a more rapid decrease in the PB form relative to the NPB form in blood, demonstrated by a change in the PB-NPB ratio from 2.86 +/- 0.55 to 1.74 +/- 0.24 (mean of 6, SD). An apparently spontaneous first order conversion from the PB to NPB form, with an apparent half-life of about eight days, was demonstrated at 37 degrees C in plasma and serum in vitro. The conversion was found to be temperature dependent and uninfluenced by the fibrinolytic components fibrinogen, fibrin, and plasminogen. Additions of a variety of enzymes or inhibitors did not interfere with the process. These results demonstrate that the PB form of alpha-2-antiplasmin is produced by the liver and that the NPB form is formed in the circulation.

Retinoic acid as antileukemic therapy in a patient with acute promyelocytic leukemia and Aspergillus pneumonia

A patient with acute promyelocytic leukemia (APL) and laboratory evidence of fibrinolysis who could not be treated with aggressive cytostatic regimens because of Aspergillus pneumonia was treated with cis-retinoic acid (RA), a substance that can induce differentiation and maturation of APL cells. After seven weeks of daily oral treatment, he went into complete remission, and signs of coagulopathy disappeared. Meanwhile, the Aspergillus pneumonia could be treated adequately. Based on the experience in this single patient, RA deserves further evaluation in the treatment of APL.