Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P04141 (granulocyte-macrophage colony-stimulating factor)
 6,790 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The MTT assay, a colorimetric assay, is found to be suitable for chemosensitivity testing. Recently, it has been suggested that hematopoietic growth factors (HGF) may enhance the effects of cytostatic drugs in acute myeloid leukemia (AML). We therefore studied the effects of granulocyte colony-stimulating factor (G-CSF), interleukin 3 (IL-3), and granulocyte-macrophage colony-stimulating factor (GM-CSF) combined with cytosine arabinoside (Ara-C), daunorubicin (DNR), mitoxantrone (MXT), or etoposide (VP-16) by using the MTT assay. The results were compared with in vitro clonogenic assays. Briefly, AML cells of nine patients were incubated in the presence or absence of G-CSF, IL-3, or GM-CSF under serum-free conditions for 24 hours. Next, for the MTT assay, Ara-C (final dilution range: 0.0024-240 micrograms/ml), DNR (final dilution range: 0.05-3.2 micrograms/ml), MXT (final dilution range: 0.05-3.2 micrograms/ml), or VP-16 (final dilution range: 0.1-100 micrograms/ml) were added and incubated for 48 hours. Cell survival was determined and IC75 values (75% reduction as compared to control cultures) were calculated. For clonogenic assays, the three lowest drug concentrations were used. After 48 hours, the clonogenic response was determined in serum-free, semi-solid cultures with G-CSF, IL-3, or GM-CSF. The results obtained by the MTT assay showed no significant enhancement of cytotoxicity by HGF on cytostatic drug preincubated cells compared to cytostatic drugs alone. The results obtained by the clonogenic assays showed increased cytotoxicity of Ara-C combined with G-CSF, IL-3, or GM-CSF. The median IC75 values of Ara-C decreased from 0.056 to 0.0168 microgram/ml with G-CSF (p = 0.01), from 0.108 to 0.0168 microgram/ml with IL-3 (p = 0.004) and from 0.12 to 0.0204 microgram/ml for GM-CSF (p = 0.02). Only moderate enhanced cytotoxicity was observed when VP-16 was combined with IL-3 (p = 0.036) or GM-CSF (p = 0.036), but not with G-CSF. No enhanced cytotoxicity of DNR and MXT to clonogenic AML cells was found when these agents were combined with HGF stimulation. The results indicate that the MTT assay underestimates HGF enhanced cytotoxicity of Ara-C or VP-16 to clonogenic cells. Therefore, the assay is not useful for accurately detecting differences of clonogenic response due to the proliferative status of cells. In this paper, the potential explanations for the failure of the MTT assay are discussed.
Leukemia 1993 Oct
PMID:Enhanced chemosensitivity in acute myeloid leukemia by hematopoietic growth factors: a comparison of the MTT assay with a clonogenic assay. 769 94

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.
Leukemia 1995 Apr
PMID:In vivo effect of human granulocyte-macrophage colony-stimulating factor (GM-CSF) on neutrophil GM-CSF receptors. 772 2

Acute myeloid leukemia (AML) cells express the surface adhesion proteins intercellular adhesion molecule-1 (ICAM-1, CD54) and lymphocyte function associated molecule-3 (LFA-3, CD58). Exposure to the myeloid growth-promoting cytokine granulocyte-macrophage colony-stimulating factor (GM-CSF) upregulates expression of ICAM-1 and LFA-3 on AML cells but does not increase their sensitivity to lysis by interleukin-2-activated natural killer cells (LAK) in 51Cr assays. However when AML cells are exposed to GM-CSF prior to incubation with LAK, their subsequent clonogenic activity is significantly reduced. If a blocking antibody to ICAM-1 is added during the incubation period of AML with LAK, the inhibitory effect is completely ablated. A less pronounced effect is observed with an antibody to LFA-3. ICAM-1 is expressed on a greater proportion of CD34+ than CD34- AML cells and exposure to GM-CSF induces a significantly greater upregulation of ICAM-1 on leukemic CD34+ cells than their CD34- counterparts. These data suggest that the inhibitory effect of IL-2-activated natural killer cells on clonogenic AML cells is mediated principally via the lymphocyte function associated molecule-1 (LFA-1)/ICAM-1 interaction. Interleukin-2 upregulates LFA-1 expression on natural killer cells. Simultaneous administration of effector cell activators such as IL-2 and target cell modulators such as GM-CSF may have a therapeutic benefit in patients with minimal residual myeloid leukemia.
Leukemia 1995 Apr
PMID:GM-CSF enhances IL-2-activated natural killer cell lysis of clonogenic AML cells by upregulating target cell expression of ICAM-1. 772 3

We have established a novel human megakaryoblastic cell line, designated as MEG-A2, from a patient with megakaryoblastic crisis of Philadelphia (Ph) chromosome positive chronic myelogenous leukemia. MEG-A2 cells showed positive phenotypes for periodic acid Schiff and alpha-naphthylbutyrate esterase reactions, but were negative for myeloperoxidase and naphthol ASD chloroacetate esterase reactions. Flow cytometric analyses of cell surface markers revealed that MEG-A2 cells had a low level of GP IIb/IIIa expression as well as apparent expressions of CD4, CD7, CD13, CD33 and CD34 antigens, but no expression of GP Ib nor glycophorin A. Stimulation with phorbol 12-myristate 13-acetate (PMA) dramatically increased the expression of megakaryocyte-related markers such as HPL-3, J15, Pit-1, Y2/51 and AN51 in MEG-A2 cells. The PMA-stimulation also induced expression of platelet peroxidase (PPO) in MEG-A2 cells on electromicroscopic observation. Proliferative responses to granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-3 (IL-3) or erythropoietin were observed, and the expression of GP IIb/IIIa was increased by stimulation with GM-CSF, IL-3, erythropoietin and interleukin-6 (IL-6). Protein S mRNA expression was seen in cultured cells on Northern blot analysis. Expression of platelet factor 4 mRNA was induced in PMA-stimulated cells, and a marked accumulation of protein was observed in the culture medium. In conclusion, a new cell line, MEG-A2, belongs to the relatively immature megakaryocytic lineage and has markedly increased megakaryocytic characteristics with PMA stimulation.
Leukemia 1995 Feb
PMID:Establishment and characterization of an immature human megakaryoblastic cell line, MEG-A2. 786 73

In preparation for a clinical trial using GM-CSF on days 4-10 of sequential high-dose cytarabine (ara-C) and asparaginase (ASNase) on days 1-3 and 8-10, potential interactions between the protein synthesis inhibitor ASNase and GM-CSF were evaluated. Granulocyte-macrophage colony-stimulating factor (GM-CSF) can stimulate acute myeloid leukemia (AML) cells to proliferate in vitro and in vivo. Log phase HL-60 cells were exposed to ara-C (10 microM x 3 h) and/or ASNase (10 U/ml during the last 2 h of ara-C). Ara-C and/or ASNase was removed and cells were incubated with or without GM-CSF (10 ng/ml). After 24, 48 and 72 h of GM-CSF there was no significant difference in the S phase fraction of cells exposed to ASNase prior to GM-CSF. Soft agar cloning efficiency was determined after retreatment with ara-C +/- ASNase 24 h into the GM-CSF incubation. GM-CSF enhanced cytotoxicity for all combinations, although this effect was of borderline significance (P = 0.0621); addition of ASNase to the treatment regimen significantly (P = 0.0229) enhanced cytotoxicity without any evidence of a negative interaction with GM-CSF. In addition, ara-C metabolism was assessed during simultaneous exposure to ara-C (10 microM x 3 h) +/- ASNase (10 U/ml the last 2 h) +/- GM-CSF (10 ng/ml beginning 24 h prior to ara-C). Ara-C incorporated into DNA (P = 0.0302) and ara-CTP formation (P = 0.0084 and P = 0.0003 at 2 and 3 h timepoints, respectively) were both increased significantly by GM-CSF, with modest non-significant increases with ASNase exposures. Neither ASNase nor GM-CSF inhibited the effects of the other in this in vitro model. Therefore, when appropriately scheduled, both GM-CSF and ASNase may potentiate ara-C cytotoxicity.
Leukemia 1995 Mar
PMID:GM-CSF and asparaginase potentiate ara-C cytotoxicity in HL-60 cells. 788 38

Circulating progenitor cells collected during periods of rapid hematopoietic reconstitution can be used successfully as hematopoietic support for super-dose chemotherapy. A major problem for collection of peripheral blood progenitor cells has been determination of optimal time to start leukapheresis and of the adequate amount of progenitor cells. This study has demonstrated that an induction chemotherapy with augmented dosage of CEF (cyclophosphamide, epirubicin, 5-fluorouracil) in conjunction with granulocyte-macrophage colony-stimulating factor (CM-CSF) successfully mobilized peripheral blood progenitor cells in 15 patients with metastatic breast cancer. By monitoring the granulocyte-macrophage colony-forming units (CFU-GM), erythrocyte burst-forming units (BFU-E), and CD34+ cells in peripheral blood daily after leukocyte nadir, we have identified an optimal 'window' in which concentrations of blood progenitor cells reached a maximum range. Although the time interval between chemotherapy and the time for maximum stimulation could vary from between 13 days to 19 days, maximum mobilization started consistently 2 days after the white blood cells (WBC) recovered to > 2.0 x 10(9)/l after nadir, and remained elevated for 4 to 5 days. A significant reduction of progenitor cells in peripheral blood and in the corresponding leukapheresis products was observed, however, from cycle 1 versus subsequent cycles (p < 0.0001), but there was no significant difference between cycles 2 and 3. When used as the sole source of hematopoietic support for super-dose chemotherapy with cyclophosphamide, mitoxantrone, and carboplatin, these progenitor cells induce rapid and sustained reconstitution in all patients. The median time from reinfusion to recovery of absolute neutrophil count (ANC) to > 0.5 x 10(9)/l was 13 days (range 9-18 days) and to an unmaintained platelet count of > 50 x 10(9)/l, 12 days (range 10-35 days). Autologous transplantation with stimulated blood progenitor cells can be an efficient alternative to bone marrow transplantation. With optimal timing for collections, as few as two leukapheresis procedures are required to obtain an adequate progenitor cell dose.
Leukemia 1993 Nov
PMID:Optimal timing for collections of blood progenitor cells following induction chemotherapy and granulocyte-macrophage colony-stimulating factor for autologous transplantation in advanced breast cancer. 796 47

Acute myeloid leukemia preceded by a myelodysplastic syndrome (MDS-AML) is generally regarded as a high-risk type of AML, where remissions are rare and of short duration. Recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) is suggested to increase the sensitivity of leukemic cells to cycle-specific drugs. In this study 14 MDS-AML patients were given rhGM-CSF together with standard induction chemotherapy (TAD). rhGM-CSF was started 48 h prior to chemotherapy and given for up to 3 weeks. The results showed eight (58%) complete and two (14%) partial remissions, while another two (14%) patients had minor responses. One patient relapsed after 1 year, and then responded a second time. rhGM-CSF had to be stopped owing to local allergic reactions in two patients, both non-responders, but was otherwise well tolerated. Compared with our historical group of controls we found significantly higher remission rates, fewer early deaths, fewer fever days, and fewer days with both neutropenia and thrombocytopenia among the patients treated with rhGM-CSF and TAD. The estimated median over-all survival was 332 days. The severity of initial myelodysplastic changes did not correlate to the outcome of therapy but the degree of peripheral blood dysplasia decreased among responding patients. MDS-AML patients in this pilot study did respond better, and with minimal toxicity, when standard induction chemotherapy was given in combination with rhGM-CSF.
Leukemia 1994 Oct
PMID:Recombinant human granulocyte-macrophage colony-stimulating factor in combination with standard induction chemotherapy in acute myeloid leukemia evolving from myelodysplastic syndromes: a pilot study. 793 58

Blast cells from up to 70% of patients with acute myeloblastic leukemia (AML) exhibit a variable degree of autonomous growth in vitro which is related to the production of autocrine growth factors including granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-1 (IL-1) and interleukin-6 (IL-6). Approximately 40% of AML blasts with autonomous growth have been reported to exhibit abnormalities of retinoblastoma (Rb) protein expression. As the Rb protein is a known transcriptional repressor of the IL-6 promoter, we have investigated the relationship between absence of Rb protein and cytokine gene expression in AML. Blasts from 28 patients were studied, 19 were Rb protein positive by Western blot and by flow cytometry for nuclear Rb protein; blasts from nine patients were Rb-negative. Of the 28 specimens tested by RT-PCR, 24 were positive for GM-CSF mRNA, 21 for IL-1 beta mRNA, and 14 for IL-6 mRNA. Only the expression of IL-6 was found to be significantly associated with loss of Rb protein expression (p < 0.02). The relationship between Rb protein and IL-6 expression was further studied by suppressing Rb protein expression with antisense oligonucleotides. In three out of seven blasts so treated, IL-6 mRNA was induced following antisense treatment whereas control sense oligonucleotides had no effect. Blasts from four patients which secreted high levels of IL-6 exhibited in vitro autonomous growth which could be partially suppressed by anti-IL-6. These results suggest that deletion of Rb protein expression is a mechanism that can dysregulate IL-6 expression in leukemic blasts and thus potentiate the autonomous growth of these cells.
Leukemia 1994 Nov
PMID:Absence of retinoblastoma protein expression results in autocrine production of interleukin-6 and promotes the autonomous growth of acute myeloid leukemia blast cells. 796 42

Because in vitro studies have indicated that granulocyte-macrophage colony-stimulating factor (GM-CSF) stimulates arabinosylcytosine (ara-C) metabolism in leukemia blasts, we analyzed the pharmacokinetics of ara-C triphosphate (ara-CTP) in the blasts of patients with chronic myelogenous leukemia who were undergoing therapy with GM-CSF and ara-C. Patients received a 2-h infusion of 1.0 g/m2 ara-C followed by daily infusions of GM-CSF (125 micrograms/m2/day i.v. over 6 h) for 2-4 days. After the last GM-CSF infusion, a second, identical dose of ara-C was administered. The cellular pharmacokinetics of ara-CTP in circulating blasts were determined during and after each ara-C dose, and the area under the accumulation and elimination curve (AUC) measured over 12 h was compared before and after GM-CSF. Ara-CTP accumulation peaked within 1 h after the end of each ara-C infusion. Comparison of the AUC of ara-CTP before and after GM-CSF administration suggested that in the blasts of three of four patients, GM-CSF treatment decreased the ara-CTP AUC; the AUC values were altered only slightly in a fourth patient. Studies of these patients' blasts incubated in vitro with ara-C before and after clinical infusion of GM-CSF revealed similar ara-CTP accumulation patterns. Together, these studies suggest that 2-4 days of GM-CSF administration does not increase the accumulation of ara-CTP in the circulating blasts from patients in the blastic phase of chronic myelogenous leukemia.
Leukemia 1994 Sep
PMID:Effect of granulocyte-macrophage colony-stimulating factor on the metabolism of arabinosylcytosine triphosphate in blasts during therapy of patients with chronic myelogenous leukemia. 809 26

Previous studies have shown that the bcl-2 gene encodes a mitochondrial protein which can inhibit the onset of apoptosis induced by withdrawal of trophic factors or by antitumour drugs. In some malignant cells bcl-2 expression has been demonstrated to be regulated by specific trophic factors which act to suppress apoptosis. Here we have investigated the effect of exogenous and autocrine granulocyte-macrophage colony-stimulating factor (GM-CSF) on both bcl-2 expression and apoptosis in acute myeloid leukaemia (AML) cells. Blasts from 31 patients with AML were studied, this included 21 patients whose cells exhibited variable degrees of autonomous growth in culture and ten patients with non-autonomous growth. Blasts with autonomous growth expressed significantly higher levels of bcl-2 protein, the intensity of fluorescence expressed as soluble fluorochrome per cell was 40.9 +/- 3.6 x 10(3) (mean +/- SD); this compared with an intensity of bcl-2 expression of 19.3 +/- 2.4 x 10(3) for blasts with non-autocrine growth (p < 0.0001 by Mann-Whitney analysis). Blasts with non-autocrine growth rapidly lost viability following 48 h of culture due to the onset of apoptosis. In these cells apoptosis was suppressed by the addition of GM-CSF and bcl-2 protein expression was found to be significantly upregulated. In contrast blasts from patients with autonomous growth and autocrine GM-CSF production failed to show any features of apoptosis in culture. In these cells bcl-2 expression was significantly downregulated following neutralization of autocrine GM-CSF by antibodies. We conclude that bcl-2 expression in AML cells is regulated by GM-CSF, and suggest that the previously demonstrated negative prognostic effect of autocrine growth as a determinant of treatment outcome in AML is in part due to the effect of autocrine GM-CSF in upregulating bcl-2 expression.
Leukemia 1994 May
PMID:Regulation of Bcl-2 expression and apoptosis in acute myeloblastic leukaemia cells by granulocyte-macrophage colony-stimulating factor. 818 35


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