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

Dendritic cells (DCs) are powerful antigen-presenting cells. Because DCs are rare cells, methods to produce them in vitro are valuable ways to study their biologic properties and to generate cells for immunotherapy. This study defines the antigen-presenting properties of DCs generated in vitro from CD34+ cells of patients with breast cancer. The combination of cytokines flt3 ligand + c-kit ligand + granulocyte-macrophage colony-stimulating factor (GM-CSF) + interleukin-4 (IL-4) + tumor necrosis factor-alpha (TNF-alpha) was used to maximize the output of mature DCs in the culture of CD34+ cells while minimizing the production of monocytes. Cells grew and differentiated into DCs as measured by a time-dependent upregulation of cell surface antigens major histocompatibility complex class II, CD1a, CD80, CD86, CD40, and CD4, so that 40% +/- 9% (n = 6) of cells in culture at day 15 were CD1a+CD14-. Markers were acquired in the same sequence as on monocytes induced to differentiate with GM-CSF + IL-4. Differentiation was marked by a time-dependent increase in allostimulatory function, which, at its peak, was more potent than in cultures of DCs generated from monocytes with GM-CSF + IL-4, but was comparable on a cell-to-cell basis to that of mature monocytes cultured in flt3-ligand + c-kit-ligand + GM-CSF + IL-4 + TNF-alpha. Both CD34+ cell-derived and monocyte-derived DCs were able to process and to present tetanus toxoid and keyhole limpet hemocyanin to autologous T cells and to present major histocompatibility class I-binding peptides to CD8+ cytotoxic T lymphocytes inducing interferon-gamma production. Altogether, these results suggest that DCs generated from CD34+ cells of patients with breast cancer with flt3 ligand, c-kit ligand, GM-CSF, IL-4, and TNF-alpha are competent antigen-presenting cells, particularly for CD8+ cytotoxic T lymphocytes, and resemble mature monocyte-derived DCs in the assays described here.
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PMID:Dendritic cells generated from CD34+ progenitor cells with flt3 ligand, c-kit ligand, GM-CSF, IL-4, and TNF-alpha are functional antigen-presenting cells resembling mature monocyte-derived dendritic cells. 1068 37

Although CD33 represents an important marker of myeloid cell differentiation, its function remains poorly defined. In view of its homology with p75/AIRM1, a recently identified surface molecule which exerts a potent inhibition on NK cell function, we re-evaluated the effect of CD33 engagement in defined myeloid cell functions. Addition of anti-CD33 mAb to cultures of CD14+ monocytes supplemented with granulocyte-macrophage colony-stimulating factor (GM-CSF), IL-4 and TNF-alpha, prevented the generation of dendritic cells. In these cultured cells, engagement of CD33 resulted in an increased surface binding of annexin-V, followed by cell death. Mature dendritic cells were resistant to the CD33-mediated effect. Also in CD34+ precursors, cultured in the presence of flt3-ligand, c-Kit-ligand, GM-CSF, IL-4 and TNF-alpha, addition of anti-CD33 mAb prevented the recovery of mature dendritic cells. These data suggest a regulatory role of CD33 in the myeloid cell maturation and may offer a tool to interfere with the monocyte/macrophage cell function as well as with the development of dendritic cells.
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PMID:Engagement of CD33 surface molecules prevents the generation of dendritic cells from both monocytes and CD34+ myeloid precursors. 1074 98

Mechanisms underlying fetal hemoglobin (HbF) reactivation in adult life have not been elucidated; particularly, the role of growth factors (GFs) is controversial. Interestingly, histone deacetylase (HD) inhibitors (sodium butyrate, NaB, trichostatin A, TSA) reactivate HbF. We developed a novel model system to investigate HbF reactivation: (1) single hematopoietic progenitor cells (HPCs) were seeded in serum-free unilineage erythroid culture; (2) the 4 daughter cells (erythroid burst-forming units, [BFU-Es]), endowed with equivalent proliferation/differentiation and HbF synthesis potential, were seeded in 4 unicellular erythroid cultures differentially treated with graded dosages of GFs and/or HD inhibitors; and (3) HbF levels were evaluated in terminal erythroblasts by assay of F cells and gamma-globin content (control levels, 2.4% and 1.8%, respectively, were close to physiologic values). HbF was moderately enhanced by interleukin-3 (IL-3) and granulocyte-macrophage colony-stimulating factor treatment (up to 5%-8% gamma-globin content), while sharply reactivated in a dose-dependent fashion by c-kit ligand (KL) and NaB (20%-23%). The stimulatory effects of KL on HbF production and erythroid cell proliferation were strictly correlated. A striking increase of HbF was induced by combined addition of KL and NaB or TSA (40%-43%). This positive interaction is seemingly mediated via different mechanisms: NaB and TSA may modify the chromatin structure of the beta-globin gene cluster; KL may activate the gamma-globin promoter via up-modulation of tal-1 and possibly FLKF transcription factors. These studies indicate that KL plays a key role in HbF reactivation in adult life. Furthermore, combined KL and NaB administration may be considered for sickle cell anemia and beta-thalassemia therapy.
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PMID:Hemoglobin switching in unicellular erythroid culture of sibling erythroid burst-forming units: kit ligand induces a dose-dependent fetal hemoglobin reactivation potentiated by sodium butyrate. 1082 43

STI 571 (formerly known as CGP 57148B) is a known inhibitor of the c-abl, bcr-abl, and platelet-derived growth-factor receptor (PDGFR) tyrosine kinases. This compound is being evaluated in clinical trials for the treatment of chronic myelogenous leukemia. We sought to extend the activity profile of STI 571 by testing its ability to inhibit the tyrosine kinase activity of c-kit, a receptor structurally similar to PDGFR. We treated a c-kit expressing a human myeloid leukemia cell line, M-07e, with STI 571 before stimulation with Steel factor (SLF). STI 571 inhibited c-kit autophosphorylation, activation of mitogen-activated protein (MAP) kinase, and activation of Akt without altering total protein levels of c-kit, MAP kinase, or Akt. The concentration that produced 50% inhibition for these effects was approximately 100 nmol/L. STI 571 also significantly decreased SLF-dependent growth of M-07e cells in a dose-dependent manner and blocked the antiapoptotic activity of SLF. In contrast, the compound had no effect on MAP kinase activation or cellular proliferation in response to granulocyte-macrophage colony-stimulating factor. We also tested the activity of STI 571 in a human mast cell leukemia cell line (HMC-1), which has an activated mutant form of c-kit. STI 571 had a more potent inhibitory effect on the kinase activity of this mutant receptor than it did on ligand-dependent activation of the wild-type receptor. These findings show that STI 571 selectively inhibits c-kit tyrosine kinase activity and downstream activation of target proteins involved in cellular proliferation and survival. This compound may be useful in treating cancers associated with increased c-kit kinase activity.
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PMID:Inhibition of c-kit receptor tyrosine kinase activity by STI 571, a selective tyrosine kinase inhibitor. 1091 Sep 6

Steel factor (SLF) and erythropoietin (Epo) play critical roles in erythropoiesis. To evaluate interactive effects of Epo and SLF receptors (R) in erythropoiesis, CD34+ and CD34 cord blood cells were transduced with human EpoR and c-kit cDNAs by retroviral mediated gene transfer. Erythroid (BFU-E) colonies derived from CD34+ or CD34 cells transduced with either the EpoR or c-kit gene were significantly increased in the presence of interleukin (IL)-3, granulocyte-macrophage colony-stimulating factor (GM-CSF), Epo, and different concentrations of SLF compared with that from mock transduced cells. This number was further enhanced by co-transduction of both genes. Enhancement was more apparent in the absence of SLF. Cell numbers in individual erythroid colonies were also significantly increased in cells transduced with both genes compared with cells transduced with a single gene. Short-term liquid culture showed that ex vivo expansion for five days and numbers of CD34+CD71+ cells in expanded cells from single CD34 cells co-transduced with both EpoR and c-kit genes were increased compared with those of EpoR or c-kit-transduced cells. These results demonstrate that co-transduction of both c-kit and EpoR enhances the proliferative capacity of erythroid progenitors under cytokine stimulation above that of single-gene transduced cells.
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PMID:Enhancing effects of co-transduction of both human erythropoietin receptor and c-kit cDNAs into hematopoietic stem/progenitor cells from cord blood on proliferation and differentiation of erythroid progenitors. 1097 33

Osteoclasts are derived from hematopoietic stem cells, but the relationship between osteoclast precursors (OCPs) and hematopoietic colony-forming cells (CFCs) has not yet been clarified. Although osteoclasts share certain cell surface markers and growth factor requirements with their macrophage and monocyte cell lineages, osteoclasts are a different lineage with regard to the requirement for signaling via c-Kit. To investigate whether CFCs are able to differentiate into osteoclasts, we performed in vitro studies of osteoclastogenesis. We performed progenitor assays in the presence of hematopoietic colony-stimulating factors. Primary colonies were plucked and examined for their potential to differentiate into osteoclasts. We found that osteoclasts are present in colonies elicited by macrophage colony-stimulating factor (M-CSF) and receptor activator of nuclear factor kB ligand (RANKL) in semisolid cultures. Moreover, a part of the cells composing the colonies elicited by granulocyte-macrophage colony-stimulating factor (GM-CSF) or M-CSF alone possessed the potential to differentiate into osteoclasts. These OCPs in the colonies were enriched in the c-Fms+ large-sized cell fraction and had a foamy cell morphology, like mature macrophages. A small number of cells in M-CSF-promoted and GM-CSF-promoted colonies formed secondary colonies in the semisolid medium containing these factors. The frequency of OCPs in these secondary colonies elicited by M-CSF was 10 times higher than that elicited by GM-CSF. Multiple origins of OCPs that differentiate into mature osteoclasts are proposed based on the observation that osteoclasts could be generated from OCPs that emerged from CFCs induced under different conditions or developmental stages.
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PMID:Presence of osteoclast precursors in colonies cloned in the presence of hematopoietic colony-stimulating factors. 1116 7

The ability to detect changes in RNA expression in single cells would greatly enhance understanding of the molecular basis of biological responses to positive and negative growth regulators. To this end, we compared expression of RNA encoding the receptors for interleukin-3 (IL-3), granulocyte-macrophage colony-stimulating factor (GM-CSF), IL-6, leukemia inhibitory factor (LIF) and stem cell factor (SCF) in populations of primitive hematopoietic progenitors (lineage marker negative, Lin(-), and Lin(-) c-Kit(+)) by RT-PCR and in situ RT-PCR. Both Lin(-) and Lin(-) c-Kit(+) progenitors expressed all receptors by RT-PCR. However, RT-PCR could not distinguish between the possibility that all cells expressed growth factor receptor RNA, or the possibility that only a proportion of cells expressed RNA. Therefore, we used in situ RT-PCR to examine growth factor receptor mRNA expression in individual cells. In contrast to RT-PCR, we observed that only 40-80% of Lin(-) cells and 75-100% of Lin(-) c-Kit(+) cells were positive for expression of the growth factor receptor subunits, demonstrating that not all cells were receptor positive. We found that in situ RT-PCR could also be used to measure induction or repression of receptor RNA expression in these cell populations. Specifically, the percentage of cells expressing IL-6alpha receptor RNA decreased from 88% positive in freshly harvested cells to 9% in Lin(-) c-Kit(+) cells cultured in IL-3 for 18 h. Thus, in situ RT-PCR can be used to detect and quantify the number of individual cells that express growth factor receptor mRNA, and may also be useful to measure changes in expression of other endogenous genes or genes introduced by transfection and gene therapy vectors.
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PMID:Detection of growth factor receptor RNA in individual hematopoietic cells by in situ RT-PCR; comparison with RT-PCR. 1168 46

We tried to efficiently generate human dendritic cells (DCs) from CD34+ peripheral blood hematopoietic progenitor cells mobilized by high-dose chemotherapy and subsequent administration of granulocyte colony-stimulating factor, using a liquid suspension culture system. Among various combinations, the combination of c-kit ligand, flt-3 ligand, c-mpl ligand (TPO), and interleukin (IL)-4 most potently generated the number of CD1a+CD14- DCs in cultures containing granulocyte-macrophage colony-stimulating factor (GM-CSF) and tumor necrosis factor alpha (TNF-alpha). The delayed addition of IL-4 on day 6 of culture gave rise to an additional increase in the yield of CD1a+CD14-DCs that were characterized by the expression of HLA-ABC, HLA-DR, CD80, CD86, and CD83. The majority of the sorted CD1a-CD14+ cells derived from 6-day culture of CD34+ cells gave rise to CD1a+CD14- DCs and CD1a-CD14+ macrophages on day 12 of culture in the presence and absence of IL-4, respectively. These findings suggest that IL-4 promotes the differentiation of CD1a- CD14+ cells derived from mobilized CD34+ peripheral blood hematopoietic progenitors to CD1a+ CD14- DCs. The majority of these DCs expressed CD68 but not the Langerhans-associated granule antigen, a finding that suggests they emerge through the monocyte differentiation pathway. The addition of TPO and IL-4 to cultures did not affect the potential of DCs to stimulate the primary allogeneic T-cell response. These findings demonstrated that the combination of c-kit ligand plus flt-3 ligand plus TPO with GM-CSF plus TNF-alpha, followed by IL-4, is useful for ex vivo generation of human DCs from mobilized CD34+ peripheral blood progenitors.
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PMID:Efficient ex vivo generation of human dendritic cells from mobilized CD34+ peripheral blood progenitors. 1172 65

To optimize conditions for ex vivo expansion of adult hematopoietic stem cells, we evaluated the co-culture of G-CSF mobilized human peripheral blood (PB) CD34(+) cells with endothelial cells engineered to overexpress various hematopoietic growth factors. Immortalized human bone marrow endothelial cells (BMEC) transfected with an expression vector carrying cDNA encoding the human telomerase reverse transcriptase (hTERT) and human umbilical vein endothelial cells (HUVEC) were transfected with combinations of adenovectors expressing murine c-kit ligand (KL), human thrombopoietin (TPO), human Flt3 ligand (FL), and human granulocyte-macrophage colony-stimulating factor (GM-CSF). Ex vivo expansion of PB CD34(+) cells from normal donors and non-Hodgkin lymphoma (NHL) patients in endothelial co-culture was evaluated weekly for total cell production, progenitor (CFU-GM, BFU-E) cell production, and stem cell production as measured by Week-5 Cobblestone Area Forming Cell assay (Wk-5 CAFC). HUVEC transfected with adenovectors expressing TPO, KL, and FL provided the best co-culture system for expanding CD34(+) cells. Maximal total nuclear cell, CFU-GM, and Wk-5 CAFC production occurred between weeks 2 and 3 with 113-fold, 25-fold, and 2.2-5.5-fold expansions, respectively. We did not detect significant differences when GM-CSF was added to the co-culture system. Expansion was also obtained using recombinant human cytokines, but was not maintained beyond 3 weeks. We demonstrated that continuous generation of high levels of TPO, FL, and KL as well as other factors secreted by endothelium provided a clinically relevant co-culture method for ex vivo expansion of stem and progenitor cells from cryopreserved CD34(+) populations.
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PMID:Ex vivo expansion of stem and progenitor cells in co-culture of mobilized peripheral blood CD34+ cells on human endothelium transfected with adenovectors expressing thrombopoietin, c-kit ligand, and Flt-3 ligand. 1184 9

Porcine haematological studies have been hampered by the lack of monoclonal antibodies against porcine CD34 or CD117 expressed on haematological progenitors. The present report describes the enumeration, phenotyping and isolation of porcine haematopoietic progenitor cells expressing stem cell factor (SCF, c-kit ligand) receptor (c-kit, CD117). Recombinant porcine (rp) SCF and granulocyte-macrophage colony-stimulating factor (GM-CSF) were expressed in the mammalian HEK293 cell-based expression system. Both were biologically active and induced the proliferation of the human erythroleukemic cell line TF-1, as well as of porcine bone marrow haematopoietic cells (BMHC), in a concentration-dependent manner. The effect of rpSCF on BMHC proliferation was synergistic with rpGM-CSF. Furthermore, rpSCF had a synergistic effect on the generation of BMHC-derived dendritic cells (DC) induced by GM-CSF and TNF-alpha. RpSCF was expressed with a 6-histidine epitope, permitting both its purification and immunological detection. Binding studies with BMHC demonstrated ligation of SCF to 4-11% of BMHC. These cells represented the SWC3(low/-)SWC8- BMHC subset, with characteristics of immature proliferative progenitor BMHC. In contrast, no expression was noted on the SWC3+SWC8- monocytic, the SWC3+SWC8+ granulocytic or the SWC3-SWC8+ B cell lineage cells. Using magnetic or fluorescence-activated cell sorting, SCF-ligating BMHC were enriched for pluripotent progenitor cells. In this manner, porcine haematological studies can be pursued in a detailed manner not before possible.
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PMID:C-kit positive porcine bone marrow progenitor cells identified and enriched using recombinant stem cell factor. 1297 92


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