Myeloid differentiation of purified CD34+ cells after stimulation with recombinant human granulocyte-monocyte colony-stimulating factor (CSF), granulocyte-CSF, monocyte-CSF, and interleukin-3.

CD34+ cells isolated from bone marrow or umbilical cord blood from healthy donors were studied for proliferation and differentiation in liquid cultures in the presence of recombinant human granulocyte-monocyte colony-stimulating factor (GM-CSF), granulocyte CSF (G-CSF), monocyte CSF (M-CSF), and interleukin-3 (IL-3), followed by immunophenotyping for myeloid and myeloid-associated cell surface markers. IL-3, either alone or together with GM-CSF, G-CSF, or M-CSF, induced, on average, 50-fold cell multiplication, GM-CSF five fold to 10-fold, and G-CSF and M-CSF less than fivefold. Cells from cultures stimulated with GM-CSF, G-CSF, or M-CSF alone contained cells with a "broad" myeloid profile, "broader" than observed in cultures with IL-3. However, since IL-3 induced rapid cell multiplication, high numbers of cells expressing early (CD13, CD33) and late myeloid markers (CD14, CD15) were recovered. The presence of other CSFs together with IL-3 did not alter the IL-3-induced effect on the cells. When 5,000 CD34+ cells were cultured with IL-3 alone, the cultures still contained 2,000 to 5,000 CD34+ cells after 14 days of culture, while cells cultured with GM-CSF, G-CSF, or M-CSF contained less than 1,000 CD34+ cells. Furthermore, 1,000 to 3,000 cells were positive for the megakaryocytic lineage marker CD41b after cultures with GM-CSF or IL-3, while cultures with G-CSF or M-CSF did not contain detectable numbers of CD41b+ cells. Finally, erythroid cells could also be generated from purified CD34+ cells. The results show that IL-3 and GM-CSF can induce rapid proliferation of purified CD34+ cells in vitro with differentiation to multiple myeloid lineages, while certain subsets maintain expression of CD34.     

Growth regulation of human acute myeloid leukemia: effects of five recombinant hematopoietic factors in a serum-free culture system

The response of human acute myeloid leukemia (AML) cells to the distinct hematopoietic growth factors (HGFs), ie, recombinant interleukin-3 (IL-3), granulocyte-macrophage-CSF (GM-CSF), granulocyte-CSF (G-CSF), macrophage-CSF (M-CSF), and erythropoietin (Epo) was investigated under well-defined serum-free conditions. Proliferative responses to these factors, when added separately as well as in combinations, were analyzed in 25 cases of human AML using 3H-thymidine incorporation and colony assays. The 3H-thymidine uptake data revealed that IL-3, GM-CSF, G-CSF, and M-CSF were stimulators of AML proliferation in 19, 15, 13, and 4 cases, respectively. Epo only stimulated DNA synthesis in the cells of the single erythroleukemia case. GM-CSF stimulation was seen only in IL-3 reactive cases and GM-CSF, when combined with IL-3, could not further elevate the DNA synthesis evoked by IL-3 alone. On the other hand, in six cases, G-CSF enhanced the IL-3- or GM-CSF-stimulated thymidine uptake. These results suggest that subpopulations of AML cells that are activated by distinct CSFs (eg, IL-3/GM-CSF-responsive cells and G-CSF-responsive cells) coexist. The 3H-thymidine incorporation assay was more sensitive for measuring CSF responses than methylcellulose colony cultures, since activation of DNA synthesis was more frequently seen than induction of colony formation. DNA synthesis experiments revealed eight different CSF response patterns among these 25 cases. CSF phenotyping may be a useful addition to the morphologic classification of AML, since these patterns directly reflect the ability of the proliferating subsets of AML cells to respond to the CSFs.     

Proliferation and differentiation of myelodysplastic CD34+ cells in serum-free medium: II. Response to combined colony-stimulating factors

Abstract: To investigate the role of colony stimulating factors (CSFs) in the proliferation and differentiation of progenitor cells from myelodysplastic syndromes (MDS), marrow progenitor cells from 18 MDS patients were highly purified using CD34 monoclonal antibody and immunomagnetic microspheres (MDS CD34+ cells). These cells were cultured in serum-free medium with various combinations of five colony stimulating factors (CSFs): recombinant human interleukin-3 (rIL-3), granulocyte/macrophage-CSF (rGM-CSF), granulocyte-CSF (rG-CSF), macrophage-CSF (rM-CSF), and erythropoietin (rEP). Among the tested CSFs, such as rM-CSF, rG-CSF, rGM-CSF and rIL-3, a combination of the first three CSFs was the most effective stimulus for the proliferation of non-erythroid MDS progenitor cells. An increase of undifferentiated “blast” cell colonies in 5/18 MDS patients occurred and these 5 patients belonged to the high-risk group. In the presence of these three CSFs, rIL-3 had no effect on the proliferation and differentiation of MDS CD34+ cells; however, IL-3 was efficient for the proliferation of MDS CD34+ cells to the erythroid lineage. rGM-CSF or rIL-3 alone did not efficiently support proliferation and differentiation of CD34+ cells. M-CSF is present in normal human serum at a concentration of 550 ±110 U/ml, a concentration exceeding that used in this study (100 U/ml). Therefore, in vivo administration of G-CSF combined with GM-CSF to MDS patients may be one of the most effective CSF combinations for proliferation of MDS progenitor cells to the non-erythroid lineage. However, the effect on the capacity for differentiation was minimal, especially in patients belonging to the high-risk group.     

Cytokine regulation of colony-stimulating factor (CSF) production in cultured human synovial fibroblasts. II. Similarities and differences in the control of interleukin-1 induction of granulocyte-macrophage CSF and granulocyte-CSF production.

Synovial fibroblasts are likely to be a significant source of granulocyte-macrophage colony-stimulating factor (GM-CSF) and granulocyte-CSF (G-CSF), which could be crucial to the pathogenesis of rheumatoid arthritis. Using specific enzyme-linked immunosorbent assays (ELISAs) and Northern analysis, GM-CSF and G-CSF expression were followed in human synovial fibroblast-like cells in response to a number of agents, either alone or in the presence of an optimal stimulatory concentration of interleukin-1 (IL-1). For both CSFs, interferon-gamma (100 U/mL) did not increase their levels but dramatically suppressed the stimulatory action of IL-1, while basic fibroblast growth factor (10(-8) mol/L), although nonstimulatory by itself, potentiated IL-1 action. The glucocorticoid, dexamethasone (10(-7) mol/L), inhibited IL-1-stimulated CSF production. However, evidence was obtained for noncoordinated CSF regulation. Cyclooxygenase inhibitors potentiated the action of IL-1 on GM-CSF synthesis but suppressed G-CSF synthesis, suggesting that endogenous cyclooxygenase products can have opposite effects in modulating the levels of each CSF. Also, the lymphokine, IL-4 (250 pmol/L), slightly inhibited GM-CSF formation in the presence of IL-1 but elevated the G-CSF levels in these cultures without having an effect by itself. Transforming growth factor beta (less than or equal to 20 ng/mL) did not modulate levels of either CSF. Mesenchymal cell production of both GM-CSF and G-CSF is generally viewed as being under coordinate control; our findings suggest that their synthesis in IL-1-stimulated human synoviocytes can be modulated by a number of agents, in some cases with divergent actions depending on which CSF is examined.     

Action of interleukin-3, G-CSF, and GM-CSF on highly enriched human hematopoietic progenitor cells: synergistic interaction of GM-CSF plus G-CSF

Purified preparations of recombinant human granulocyte-macrophage colony-stimulating factor (GM-CSF), granulocyte CSF (G-CSF), and interleukin 3 (IL-3 or multi-CSF) alone and in combination, have been compared for their stimulatory effects on human granulocyte-macrophage colony forming cells (GM-CFC). In cultures of unseparated normal human bone marrow, the combinations of G-CSF plus IL-3 and GM-CSF plus IL-3 stimulated additive numbers of GM colonies, while GM-CSF plus G-CSF stimulated greater than additive numbers of GM colonies, compared with the sum of the colony formation obtained with each factor alone. Cultures of unseparated bone marrow, harvested from patients four to six days after administration of 5-fluorouracil (5-FU), resulted in additive GM colony formation with GM-CSF plus G-CSF, GM-CSF plus IL-3, and G-CSF plus IL-3. In order to address the possibility of secondary factor involvement in the synergistic interaction of GM-CSF and G-CSF, CD33+/CD34+ colony forming cells were separated from normal and post FU marrow by two color fluorescence activated cell sorting. In cultures of CD33+/CD34+ cells the combination of GM-CSF plus G-CSF stimulated a synergistic increase in GM colonies while GM-CSF plus IL-3 stimulated additive numbers of colonies. These results suggest that GM-CSF, G-CSF, and IL-3 stimulate distinct populations of GM-CFC. Furthermore GM-CSF and G-CSF interact synergistically and this action is a direct effect on progenitor cells not stimulated by GM-CSF or G-CSF alone.     

Maturation of human acute myeloid leukaemia in vitro; the response to five recombinant haematopoietic factors in a serum-free system

The abilities of human recombinant IL-3, GM-CSF, G-CSF, M-CSF and Epo to induce maturation in human AML cells in vitro were investigated using cell specimens from 25 AML patients. The experiments were carried out under exactly defined serum-free culture conditions. In the absence of CSFs, monocytic and/or granulocytic maturation was detected in 14/25 cases. IL-3, GM-CSF, G-CSF and M-CSF elevated the proportions of monocyte/macrophages in 3/25, 2/25, 1/25 and 6/25 cases respectively, and increased the percentages of mature granulocytes in 2/25, 1/25, 1/25 and 0/25 cases, and if so only to a limited extent (values below 50%). The 3H-thymidine (3H-TdR) uptake studies revealed that IL-3, GM-CSF, G-CSF and M-CSF were efficient stimulators of DNA synthesis of AML cells in 19, 15, 13 and four of those cases, respectively. Thus, although the cells in most cases responded to CSFs by activation of DNA synthesis, they were unable to give rise to terminally differentiated stages. Provision of CSFs in combination was more frequently effective in enhancing maturation and also increased the magnitude of maturation response. Monocytic versus granulocytic maturation of AML cells after culture did not correlate with the FAB cytology nor with the type of CSF presented; but generally granulocytic maturation was an infrequent phenomenon. Epo stimulated erythroid differentiation and DNA synthesis only in the case of erythroleukaemia, but it had no effect on the cells of 10 other AML cases. Extrapolation of these in vitro findings would suggest that CSFs would have a limited therapeutic utility to induce AML cell maturation in vivo and that hazards of stimulating blast cell proliferation with these factors may be anticipated.     

Interleukin-1, tumor necrosis factor, and the production of colony- stimulating factors by cultured mesenchymal cells

Although the genes for four hematopoietic colony-stimulating factors (CSFs) have been cloned, neither the mechanism of the regulation of their production nor their cellular origins have been established with certainty. Monocytes are known to produce colony-stimulating and burst- promoting activities, as well as several monokines such as interleukin- 1 (IL-1) and tumor necrosis factor (TNF). These monokines indirectly stimulate other mesenchymal cells to produce certain colony-stimulating factors such as granulocyte-macrophage CSF (GM-CSF). To determine whether monocytes produce other CSFs and if so, to compare the mechanism of regulation of production with that of endothelial cells and fibroblasts, we investigated the synthesis of CSFs by monocytes, human umbilical vein endothelial cells, and fibroblasts. We used total cellular RNA blot analysis to determine interleukin-3 (IL-3), GM-CSF, granulocyte CSF (G-CSF), and monocyte CSF (M-CSF) messenger RNA (mRNA) content and immunoprecipitation or bioassay to confirm the presence of the specific secreted proteins. The results indicate that M-CSF mRNA and protein are produced constitutively by all three cell types and their level of expression does not increase after induction. In contrast, GM-CSF and G-CSF mRNAs are barely detectable in uninduced monocytes and show an increase in expression after lipopolysaccharide treatment. Retrovirus-immortalized endothelial cells, unlike primary endothelial cells or both primary and immortalized fibroblasts, produce IL-1 constitutively; this correlates with their constitutive production of GM-CSF and G-CSF. IL-3 mRNA was not detectable in any of these cells either before or after induction. The results indicate that these mesenchymal cells can produce three CSFs: GM-CSF, G-CSF, and M-CSF; furthermore, the data suggest that the mechanism of regulation of M-CSF production is different from that of GM-CSF and G-CSF, and that the latter two inducible CSFs are regulated by different factors in monocytes compared with the other mesenchymal cells.     

Tumor necrosis factor-alpha strongly potentiates interleukin-3 and granulocyte-macrophage colony-stimulating factor-induced proliferation of human CD34+ hematopoietic progenitor cells.

Previous studies have shown that tumor necrosis factors (TNFs) inhibit the proliferative effects of crude or purified colony-stimulating factors (CSFs) on low density human bone marrow cell fractions. In the present study we investigated the effects of TNF alpha on the growth of highly purified CD34+ human hematopoietic progenitor cells (HPC) in response to recombinant CSFs. In short-term liquid cultures (5 to 8 days), TNF alpha strongly potentiates interleukin-3 (IL-3) and granulocyte-macrophage-CSF (GM-CSF)-induced growth of CD34+ HPC, while it has no proliferative effect per se. Within 8 days, the number of viable cells obtained in TNF alpha-supplemented cultures is threefold higher than in cultures carried out with IL-3 or GM-CSF alone. Secondary liquid cultures showed that the potentiating effect of TNF alpha on IL-3-induced proliferation of CD34+ HPC does not result from an IL-3-dependent generation of TNF alpha responsive cells. Limiting dilution analysis indicates that TNF alpha increases both the frequency of IL-3 responding cells and the average size of the IL-3-dependent clones. The potentiating effect of TNF alpha on IL-3- and GM-CSF-dependent growth of CD34+ HPC is also observed in day 7 colony assays. Under these short-term culture conditions, TNF alpha does not appear to accelerate cell maturation as a precursor morphology is retained. Finally, TNF alpha inhibits the relatively weak growth-promoting effect of granulocyte-CSF (G-CSF), which acts on a more committed subpopulation of CD34+ HPC different from that recruited by IL-3 and GM-CSF. TNF beta displays the same modulatory effects as TNF alpha. Thus, TNFs appear to enhance the early stages of myelopoiesis.     

Recombinant gibbon interleukin-3 acts synergistically with recombinant human G-CSF and GM-CSF in vitro

Recombinant gibbon interleukin-3 (IL-3) is a multilineage hematopoietic colony-stimulating factor (CSF) that recently was cloned and found to be highly homologous with human IL-3. Gibbon IL-3, as well as human granulocyte-CSF (G-CSF) and human granulocyte-macrophage CSF (GM-CSF), stimulated normal human bone marrow cells to form myeloid colonies in soft agar in a sigmoidal dose-response manner. When IL-3 was added to increasing concentrations of G-CSF or GM-CSF, synergistic colony formation occurred as compared with the effects of each CSF alone. Synergism was also noted when G-CSF was added with GM-CSF and when all the CSFs were added simultaneously. The combination of IL-3 and GM-CSF was less stimulatory than all the other CSF combinations. At day 11 of culture, IL-3 induced granulocyte-macrophage (38%), eosinophil (30%), granulocyte (18%), and macrophage (14%) colony formation. In summary, gibbon IL-3 is a growth factor that can synergize with other CSFs to enhance proliferation of myeloid-committed progenitors, suggesting that combinations of CSFs may have clinical utility in patients with neutropenia of various etiologies.     

Activation and proliferation signals in murine macrophages: synergistic interactions between the hematopoietic growth factors and with phorbol ester for DNA synthesis

There has been recent interest in the synergistic interactions between the growth factors involved in the in vitro control of hematopoiesis and other cell lineages. As a convenient model system, such interactions governing the DNA synthesis in murine bone marrow-derived macrophages (BMMs) were studied. By themselves, murine colony- stimulating factor-1 (CSF-1) and recombinant murine granulocyte- macrophage CSF (GM-CSF) were stimulators of DNA synthesis in quiescent or noncycling BMMs, whereas recombinant murine interleukin-3 (IL-3) and the phorbol ester, 12-O-tetradecanoyl-phorbol-13-acetate (TPA), were weak mitogens. On the other hand, murine granulocyte CSF (G-CSF), concanavalin A (Con A), and lipopolysaccharide (LPS) were inactive on their own. When the quiescent BMMs were exposed to combinations of the CSFs, there were striking synergistic effects for both GM-CSF and IL-3 with suboptimal doses of CSF-1, with a smaller effect for GM-CSF with IL-3 and little or no effect for CSF-1 with G-CSF. CSF-1, GM-CSF, and IL-3 could also synergize with TPA; CSF-1 cooperated with 1-oleoyl-2- acetylglycerol (OAG), both sets of results pointing to an interaction with protein kinase C. LPS completely abolished the CSF-1-mediated stimulation of DNA synthesis. We propose that BMMs are suitable normal cells in which to examine in depth the various mechanistic possibilities for these interactions.     

Malignancy: Insulin-like Growth Factor-1 (IGF-1) is a Costimulator of the Expansion of Lineage Committed Cells Derived from Peripheral Blood Mobilized CD34+ Cells in Multiple Myeloma Patients

The effect of insulin-like growth factor-1 (IGF-1) on highly enriched human apheresis CD34(+) progenitor cells was investigated in vitro. The progenitor cells were mobilized by treatment with cyclophosphamide + granulocyte - colony stimulating factor (G-CSF) in patients with multiple myeloma. CD34(+) cells were cultured for 7 days in serumfree medium containing stem cell factor (SCF), granulocyte-macrophage colony stimulating factor (GM-CSF) and interleukin-3 (IL-3), and this is referred to as cytokine-dependent proliferation. After 7 days of cytokine-dependent proliferation the total number of viable cells increased 1.6-8.2 times, and subsets of cells expressing the granulocyte marker CD15, the myelomonocytic marker CD64 and the erythrocyte phenotype CD71(high) /CD64(-) were detected among the in vitro cultured cells. Addition of G-CSF together with SCF + IL-3 + GM-CSF increased the number of CD15(+) and CD64(+) cells, but without altering the number of erythroid cells. IGF-1 caused a dose-dependent increase in the number of CD15(+), CD64(+) and CD71(high) /CD64(-) cells, and this increase was detected when cells were cultured in both SCF + IL-3 + GM-CSF alone and G-CSF + SCF + IL-3 + GM-CSF. A minor subset of CD34(+) cells could still be detected among in vitro cultured cells and the number of CD34(+) cells was not altered by adding G-CSF and/or IGF-1. Morphologically recognizable mature granulocytes or erythroid cells could not be detected for any of the combinations investigated. We conclude that IGF-1 can enhance the in vitro proliferation of committed progenitor cells derived from apheresis CD34(+) cells.     

Mechanism of synergy between granulocyte-macrophage colony-stimulating factor and granulocyte colony-stimulating factor in colony formation from human marrow cells in vitro

The synergy of human granulocyte-macrophage colony-stimulating factor (GM-CSF) and human granulocyte colony-stimulating factor (G-CSF) in the colony formation derived from human marrow cells was studied. The colony formation stimulated by GM-CSF plus G-CSF was dependent on the dose of each CSF, with the plateau for the number of GM colonies being higher than the sum of the individual plateaus by GM-CSF or G-CSF. Analysis of the colonies formed by GM-CSF plus G-CSF revealed efficient formation of neutrophil and monocyte colonies. To study the effect of GM-CSF and G-CSF on the maintenance of the progenitors that respond to the synergy of the CSFs, addition of each CSF to the medium of clonal cell culture was delayed. The progenitors that formed colonies on day 7 due to synergy of the CSFs were perfectly maintained by GM-CSF for at least 72 h and the progenitors that formed colonies on day 14 due to synergy of the CSFs were partly maintained by G-CSF or GM-CSF. The DNA synthetic rate of the progenitor cells that respond to GM-CSF plus G-CSF was significantly lower than those that respond to GM-CSF or G-CSF. According to light scatter analysis of phagocyte-depleted marrow mononuclear cells (PD-MMCs) using a flow cytometer, the peak population of progenitors that respond to GM-CSF plus G-CSF was in the smaller part of the PD-MMCs than those to GM-CSF or G-CSF. These results indicated that the progenitors to the synergy of GM-CSF and G-CSF are in a different proliferative state than those to each CSF. The synergy of GM-CSF and G-CSF depends on each CSF maintaining the viability of a different population of GM progenitors that can form GM colonies by both CSFs together.     

Proliferative responses to interleukin-3 and granulocyte colony-stimulating factor distinguish a minor subpopulation of CD34-positive marrow progenitors that do not express CD33 and a novel antigen, 7B9.

Human hematopoietic colony-forming cells (CFC) express the CD34 antigen (CD34+) as well as differentiation antigens such as CD33 and HLA-DR. CD34+ cells that do not express these latter differentiation antigens have been shown to contain few CFC in direct culture, but generate increasing numbers of CFC when cultured over a marrow stromal cell layer in the long-term culture system. In this study we determined if CD34+ cells with low or absent expression of CD33 and a novel antigen, 7B9 (CD34+CD33-7B9-), could be distinguished from CD34+ cells expressing these antigens (CD34+CD33+7B9+) based on their proliferative responses to interleukin-3 (IL-3) and granulocyte colony-stimulating factor (G-CSF) in a short-term liquid culture system. These two populations were separated by fluorescence-activated cell sorting, cultured with IL-3 (10 ng/mL), G-CSF (100 ng/mL), or IL-3 and G-CSF, and 3H-thymidine uptake was measured. CD34+CD33-7B9- cells proliferated in the presence of IL-3, but not G-CSF. However, a synergistic response to the combination of IL-3 and G-CSF was seen in most experiments. In contrast, CD34+CD33+7B9+ cells proliferated in the presence of either IL-3 or G-CSF but did not display an additive or synergistic response to the combination of IL-3 and G-CSF. In colony-forming assays performed before and after liquid culture, the CD34+CD33-7B9- cells in two experiments contained 0.3% and 2.2% of all sorted marrow CFC before liquid culture and generated 40-fold and ninefold increases in the number of granulocyte-macrophage colony-forming units (CFU-GM), respectively, after liquid culture with IL-3 and G-CSF. In contrast, the CD34+CD33+7B9+ cells contained 99.7% and 97.8% of all sorted marrow CFC before liquid culture and had no change or a threefold increase in the number of CFU-GM, respectively, after liquid culture with IL-3 and G-CSF. Single-cell liquid cultures containing IL-3 and G-CSF with cells that were either CD34+CD33-7B9- and depleted of mature lymphoid cells (CD34+lin-) or were CD34+lin+ showed that a higher proportion of wells containing a CD34+lin- cell gave rise to one or more CFC (8.7%) than did wells containing a CD34+lin+ cell (2.9%), with the responding cells in the former population giving rise to an average of 2.9 +/- 0.6 CFC and in the latter population, 2.0 +/- 1.0 CFC.(ABSTRACT TRUNCATED AT 400 WORDS)     

Interleukin-3 is significantly more effective than other colony- stimulating factors in long-term maintenance of human bone marrow- derived colony-forming cells in vitro

Human bone marrow cells cultured for 21 days in the presence of recombinant human interleukin-3 (IL-3) produced up to 28 times more colony-forming cells (CFC) than could be obtained from cultures stimulated with granulocyte colony stimulating factor (G-CSF) or granulocyte-macrophage CSF (GM-CSF). IL-3-cultured cells retained a multipotent response to IL-3 in colony assays but were restricted to formation of granulocyte colonies in G-CSF and granulocyte or macrophage colonies in GM-CSF. Culture of bone marrow cells in IL-3 also led to accumulation of large numbers of eosinophils and basophils. These data contrast with the effects of G-CSF, GM-CSF, and IL-3 in seven-day cultures. Here both GM-CSF and IL-3 amplified total CFC that had similar multipotential colony-forming capability in either factor. G-CSF, on the other hand, depleted IL-3-responsive colony-forming cells dramatically, apparently by causing these cells to mature into granulocytes. The data suggest that a large proportion of IL-3- responsive cells in human bone marrow express receptors for G-CSF and can respond to this factor, the majority becoming neutrophils. Furthermore, the CFC maintained for 21 days in IL-3 may be a functionally distinct population from that produced after seven days culture of bone marrow cells in either IL-3 or GM-CSF.     

Expansion of granulocyte colony-stimulating factor/chemotherapy-mobilized CD34+ hematopoietic progenitors: role of granulocyte-macrophage colony-stimulating factor/erythropoietin hybrid protein (MEN11303) and interleukin-15

Ex vivo stroma-free static liquid cultures of granulocyte colony-stimulating factor (G-CSF)/chemotherapy-mobilized CD34+ cells were established from patients with epithelial solid tumors. Different culture conditions were generated by adding G-CSF, granulocyte-macrophage colony-stimulating factor (GM-CSF), Flt3 ligand (Flt3), megakaryocyte growth and development factor (Peg-rHuMGDF), GM-CSF/erythropoietin (EPO) hybrid protein (MEN11303), and interleukin-15 (IL-15) to the basic stem cell factor (SCF) + interleukin-3 (IL-3) + EPO combination. This study showed that, among the nine different combinations tested in our 5% autologous plasma-containing cultures, only those containing IL-3/SCF/Flt3/MEN11303 and IL-3/SCF/Flt3/MEN11303/IL-15 significantly expanded colony-forming unit granulocyte-macrophage (CFU-GM), burst-forming unit erythroid (BFU-E), long-term culture-initiating cells (LTC-IC), CD34+, and CD34+/CD38- cells after 14 days of culture. Particularly, the addition of IL-15 to IL-3/SCF/Flt3/MEN11303 combination produced a significant increase of LTC-IC, with an average 26-fold amplification as compared to input cells, without any detrimental effect on CFU-GM and BFU-E expansion. This combination also produced a statistically significant 3.6-fold expansion of primitive CD34+/CD38- cells. Moreover, this study confirms the previously described erythropoietic effect of MEN11303, which, in our experience, was the only factor capable of expanding BFU-E. Compared to equimolar concentrations of GM-CSF and EPO, MEN11303 hybrid protein showed a significantly higher capacity of expanding CFU-GM, BFU-E, LTC-IC, CD34+, and CD34+/CD38- cells when these cytokines were tested in combination with IL-3/SCF/Flt3. These cultures indicated that Peg-rHuMGDF addition to IL-3/SCF/EPO/Flt3 does not affect CFU-GM and BFU-E expansion but, unlike G-CSF or GM-CSF, it does not decrease the ability of Flt3 to expand primitive LTC-IC. These studies indicate that, starting from G-CSF/chemotherapy-mobilized CD34+ cells, concomitant expansion of primitive LTC-IC, CFU-GM, BFU-E, CD34+, and CD34+/CD38- cells is feasible in simple stroma-free static liquid cultures, provided IL-3/SCF/Flt3/MEN11303/IL-15 combination is used as expanding cocktail in the presence of 5% autologous plasma.     

Synergistic myelopoietic actions in vivo after administration to mice of combinations of purified natural murine colony-stimulating factor 1, recombinant murine interleukin 3, and recombinant murine granulocyte/macrophage colony-stimulating factor.

Combinations of low dosages of purified murine hematopoietic colony-stimulating factors (CSFs)--L-cell CSF type 1 (CSF-1), recombinant interleukin 3 (IL-3), and recombinant granulocyte/macrophage CSF (GM-CSF)--were compared with single CSFs for their influence on the cycling rates and numbers of bone marrow granulocyte/macrophage, erythroid, and multipotential progenitor cells in vivo in mice pretreated with human lactoferrin. Lactoferrin was used to enhance detection of the stimulating effects of exogenously administered CSFs. Concentrations of CSFs that were not active in vivo when given alone were active when administered together with other types of CSF. The concentrations of CSF-1, IL-3, and GM-CSF needed to increase progenitor cell cycling rates were reduced by factors of 40-200, 10-50, and 40- greater than 400, respectively; the concentrations needed to increase progenitor cell numbers were reduced by factors of 40-500 (CSF-1), 20-80 (IL-3), and greater than 40- greater than 200 (GM-CSF) when these forms of CSFs were administered in combination with low dosages of one of the other forms of CSFs. The results demonstrate that different CSFs can synergize when administered in vivo to increase the cycling rates and numbers of marrow hematopoietic progenitor cells. These findings may be of relevance physiologically to the regulation of myeloid blood cell production by CSFs.     

Hematopoietic recovery following high-dose combined alkylating-agent chemotherapy and autologous bone marrow support in patients in phase-I clinical trials of colony-stimulating factors: G-CSF,GM-CSF,IL-1, IL-2, M-CSF

Summary Hematopoietic recovery in 115 patients with metastatic breast cancer or metastatic melanoma, enrolled in phase-I studies of recombinant growth factors while undergoing treatment with high-dose chemotherapy with autologous bone marrow support, was examined with assays of bone marrow progenitor cells and peripheral blood progenitor cells, and by evaluation of peripheral blood counts. Groups of patients receiving hematopoietic cytokine support [with interleukin-1 (IL-1), interleukin-2 (IL-2), granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage CSF (GM-CSF), or monocyte CSF (M-CSF)] post marrow infusion were compared with contemporaneous control patients not receiving growth factor support. Patients receiving GM-CSF demonstrated statistically significant increases in the growth of granulocyte/macrophage colony-forming units (CFU-GM) in the bone marrow and peripheral blood compared with control patients. The effect of GM-CSF was dose dependent in the early period post marrow infusion (day +6) with bone marrow CFU-GM colonies at doses 8–16 g/kg/ day 34 times those measured in controls. Significant increases in bone marrow multipotential progenitor cells (CFU-GEMM) were seen in patients receiving GMCSF day + 21 post marrow infusion. Patients receiving IL-1 demonstrated significant increases in bone marrow CFU-GM at day +21, maximal at dosages of 24–32 ng/kg/day. There were no significant increases in burst forming unit-erythroid (BFU-E) among any study group. Patients receiving G-CSF had significantly increased absolute neutrophil counts (ANC) and total white blood cell counts (WBC) by day +11 post transplant compared with control patients. Patients receiving GM-CSF demonstrated significantly increased WBC (greater than 2000/mm³) at day +11 and ANC greater than 500/mm³ at day +16. Optimal dose of GCSF and GM-CSF to stimulate neutrophil recovery post transplant was 4–8 g/kg/day and 8–16 g/kg/day, respectively. Platelet recovery did not differ among the six study groups. These data demonstrate accelerated myeloid recovery after high-dose chemotherapy and autologous bone marrow support in patients receiving either G-CSF or GM-CSF. Moreover, GM-CSF and IL-1 stimulate myelopoiesis at the level of bone marrow CFU-GM, while G-CSF causes earlier neutrophil recovery peripherally.This work has been supported in part by The National Heart, Lung, and Blood Institute, grant P01CA47741. Joanne Kurtzberg, MD is a scholar of the Leukemia Society of America     

Quantitative cell-cycle progression analysis of the first three successive cell cycles of granulocyte colony-stimulating factor and/or granulocyte-macrophage colony-stimulating factor-stimulated human CD34+ bone marrow cells in relation to their colony formation

The bromodeoxyuridine (BrdU)-Hoechst flow cytometric technique was applied to study the immediate cell kinetic response of highly purified human (h) bone marrow progenitor cells (CD(34+)-sorted fraction) to h granulocyte colony-stimulating factor (G-CSF) and/or h granulocyte- macrophage colony-stimulating factor (GM-CSF). The technique permits us to differentiate cycling from noncycling cells and to make a quantitative assessment of cell cycles after stimulation. Semisolid agar and single-cell liquid cultures were also performed to compare these initial events to the effects observed after 14 days of culture. The combination of G-CSF plus GM-CSF, acting synergistically in day 14 cultures, was found to have a subadditive effect in the first cell cycles, thereby indicating partial overlap of the different target cells. However, this combination accelerated transit through the cell cycle, as could be seen from the higher number of cells in the third cell cycle after 72 hours of stimulation. We conclude that, apart from the unresponsive cells, the CD34+ compartment consists of cells responsive to both G-CSF and GM-CSF, and cells responsive to either one of the CSFs alone, and that the combination of the two CSFs speeds up the cell cycle traverse rate for a significant fraction of the target cells that are initially responsive for both G-CSF and GM-CSF. The latter supports the hypothesis of an overlapping signalling pathway of G-CSF and GM-CSF.     

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.