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)

Granulocyte colony-stimulating factor (G-CSF) is a potent stimulator of the growth of normal and malignant hematopoietic cells and synergizes with other factors such as interleukin-3 (IL-3) and granulocyte-macrophage colony-stimulating factor (GM-CSF). The action of G-CSF is mediated through a specific membrane receptor, however it is not clear if all of the effects of G-CSF are direct or indirect. As a step towards addressing this problem, a recombinant diphtheria toxin (DT)-related human G-CSF fusion protein has been constructed and purified from E. coli. The 70,000 dalton chimeric protein has immunologic determinants characteristic of both DT and G-CSF. At high concentrations, DAB486-G-CSF is cytotoxic towards G-CSF-dependent OCI/AML1 cells, but not factor independent OCI/AML3 cells; colony formation by G-CSF-responsive leukemic blasts from a patient with acute myeloblastic leukemia (AML) was also inhibited. The G-CSF fusion toxin displayed ADP-ribosyltransferase activity in a cell-free system. Genetic conjugation of G-CSF to an enzymatically inactive DT mutant, CRM197, resulted in a 200-fold reduction in the ability of G-CSF to stimulate normal bone marrow colony formation. These results suggest that fusion of G-CSF to DT sequences interferes with some of the activity but not the specificity of the ligand binding domain of the molecule. Nevertheless, DAB486-G-CSF may be included with the increasing number of other toxin-hormone fusion proteins whose toxicity is directed towards specific receptor-bearing cells, and may represent a novel approach towards the study and treatment of leukemia.
 ...
PMID:Cytotoxicity of a recombinant diphtheria toxin-granulocyte colony-stimulating factor fusion protein on human leukemic blast cells. 750 48

AML1 is involved in the (8;21) translocation, associated with acute myelogenous leukemia (AML)-type M2, which results in the production of the AML1-ETO fusion protein: the amino-terminal 177 amino acids of AML1 and the carboxyl-terminal 575 amino acids of ETO. The mechanism by which AML1-ETO accomplishes leukemic transformation is unknown; however, AML1-ETO interferes with AML1 transactivation of such AML1 targets as the T-cell receptor beta enhancer and the granulocyte-macrophage colony-stimulating factor promoter. Herein, we explored the effect of AML1-ETO on regulation of a myeloid-specific AML1 target, the macrophage colony-stimulating factor (M-CSF) receptor promoter. We found that AML1-ETO and AML1 work synergistically to transactivate the M-CSF receptor promoter, thus exhibiting a different activity than previously described. Truncation mutants within the ETO portion of AML1-ETO revealed the region of ETO necessary for the cooperativity between AML1 and AML1-ETO lies between amino acids 347 and 540. Endogenous M-CSF receptor expression was examined in Kasumi-1 cells, derived from a patient with AML-M2 t(8;21) and the promonocytic cell line U937. Kasumi-1 cells exhibited a significantly higher level of M-CSF receptor expression than U937 cells. Bone marrow from patients with AML-M2 t(8;21) also exhibited a higher level of expression of M-CSF receptor compared with normal controls. The upregulation of M-CSF receptor expression by AML1-ETO may contribute to the development of a leukemic state in these patients.
 ...
PMID:Synergistic up-regulation of the myeloid-specific promoter for the macrophage colony-stimulating factor receptor by AML1 and the t(8;21) fusion protein may contribute to leukemogenesis. 887 34

Vaccinia virus (VV) infection induces protective T- and B-cell responses, making recombinants based on VV good candidates for the development of effective vaccines to other viruses. VV recombinants expressing the human immunodeficiency virus (HIV) envelope protein (Env) have been generated in several laboratories and shown to induce anti-HIV cellular and humoral immune responses in vaccinated humans and in chimpanzees. To increase the immunogenicity of the Env antigen, a VV recombinant was generated that expresses a chimeric antigen consisting of the Env protein fused to an immunostimulatory cytokine, granulocyte-macrophage colony-stimulating factor (GM-CSF). The chimeric protein retained GM-CSF biological activity when expressed by this recombinant virus (VV-GM-gp120) in cells infected in vitro. Infection of BALB/c mice with VV-GM-gp120 triggered a higher HIV-specific cellular immune response, as measured by interferon-gamma production, than that induced by a VV recombinant expressing the native Env protein. Moreover, although anti-gp120 antibody titres were similar in sera from mice inoculated with either of the VV recombinants, immunization with the recombinant expressing the fusion protein elicited antibodies against a broader spectrum of Env epitopes. These results indicate that HIV Env antigen fusion to GM-CSF provides a means to improve the anti-HIV immune response.
 ...
PMID:A human immunodeficiency virus type 1 Env-granulocyte-macrophage colony-stimulating factor fusion protein enhances the cellular immune response to Env in a vaccinia virus-based vaccine. 993 5

F1 antigen (Caf1) of Yersinia pestis is assembled via the Caf1M chaperone/Caf1A usher pathway. We investigated the ability of this assembly system to facilitate secretion of full-length heterologous proteins fused to the Caf1 subunit in Escherichia coli. Despite correct processing of a chimeric protein composed of a modified Caf1 signal peptide, mature human interleukin-1beta (hIL-1beta), and mature Caf1, the processed product (hIL-1beta:Caf1) remained insoluble. Coexpression of this chimera with a functional Caf1M chaperone led to the accumulation of soluble hIL-1beta:Caf1 in the periplasm. Soluble hIL-1beta:Caf1 reacted with monoclonal antibodies directed against structural epitopes of hIL-1beta. The results indicate that Caf1M-induced release of hIL-1beta:Caf1 from the inner membrane promotes folding of the hIL-1beta domain. Similar results were obtained with the fusion of Caf1 to hIL-1beta receptor antagonist or to human granulocyte-macrophage colony-stimulating factor. Following coexpression of the hIL-1beta:Caf1 precursor with both the Caf1M chaperone and Caf1A outer membrane protein, hIL-1beta:Caf1 could be detected on the cell surface of E. coli. These results demonstrate for the first time the potential application of the chaperone/usher secretion pathway in the transport of subunits with large heterogeneous N-terminal fusions. This represents a novel means for the delivery of correctly folded heterologous proteins to the periplasm and cell surface as either polymers or cleavable monomeric domains.
 ...
PMID:Secretion of recombinant proteins via the chaperone/usher pathway in Escherichia coli. 1128 37

Deregulation of PI3K/Akt and Raf/Mek/Erk signal transduction cascades is one of the principal causes of neoplastic transformation. The inactivation of the proapoptotic protein Bad, upon phosphorylation by different kinases of these two pathways, may play an important role in different human malignancies. Therefore, we have expressed and purified a new chimeric protein, hGM-CSF-Bad, linking the human granulocyte-macrophage colony-stimulating factor to the N-terminus of the proapoptotic protein human Bad, to deliver Bad into tumor cells and induce apoptosis. Indeed, the human GM-CSF receptor is a good target because it is overexpressed on many leukemias and solid tumors and is not detectable on stem cells. We found that the chimeric protein binds the human GM-CSF receptor, is endocytosed, and appears to reach the cytosol via retrograde ER transport. After entering cells, the protein is able to induce apoptosis of human leukemia cells and human colon and gastric carcinoma cell lines (IC(50) values as low as 1 muM). We conclude that GM-CSF-Bad can overcome the inappropriate survival stimuli in transformed cells and restore the apoptotic pathway. The completely human sequence and the elevated selectivity for cancer cells could prevent immunogenicity and the nonspecific toxicity of targeted toxins in future clinical application of this fusion protein.
 ...
PMID:A chimeric protein induces tumor cell apoptosis by delivering the human Bcl-2 family BH3-only protein Bad. 1575 84

Chimeric proteins are composed of a cell-targeting moiety and a cell-killing moiety. In this study, a chimeric protein, STXA1-GM-CSF, composed of catalytic domain of Shiga toxin (A1) and granulocyte-macrophage colony-stimulating factor (GM-CSF) was constructed and expressed in E. coli. Cytotoxicity, receptor blocking, and neutralization experiments revealed that the chimeric protein induced cytotoxic effect on different cell lines. This effect was found to be specific, due to the presence of the killing moiety (A1), which exerts its effect through a specific GM-CSF-targeting domain, by binding to its receptor present on those cell lines. These initial investigations indicate that the chimeric protein was functional; further analyses are required for its application.
 ...
PMID:Selective cytotoxicity of recombinant STXA1-GM-CSF protein in hematopoetic cancer cells. 1659 7

Bcl-XL, a member of the Bcl-2 protein family, is able to suppress cell death induced by diverse stimuli in many cell types, including hematopoietic cells. Human granulocyte-macrophage colony-stimulating factor (GM-CSF) is a cytokine that promotes the proliferation and maturation of neutrophils, eosinophils, and macrophages from bone marrow progenitors. We fused GM-CSF to Bcl-XL and examined the capacity of this chimera to bind human cells through the GM-CSF receptor and prevent apoptosis. We found that the chimeric protein increased the proliferation of human monocytes in culture from 24 h until at least 72 h. In the presence of different apoptotic agents, GM-CSF-Bcl-XL protected cells from induced cell death and promoted proliferation, whereas GM-CSF alone was completely inhibited. In the presence of cytarabine, GM-CSF-Bcl-XL was able also to promote the differentiation of the CD34+ myeloid precursor whereas Lfn-Bcl-XL, lacking the GM-CSF domain-stimulated cell proliferation and not differentiation. We conclude that recombinant GM-CSF-Bcl-XL binds the GM-CSF receptor on human monocyte/macrophage cells and bone marrow progenitors inducing differentiation and allowing Bcl-XL entry into cells where it blocks cell death and allows amplified cell proliferation. This fully human fusion protein has potential to prevent monocytopenia and represents a new strategy for engineering anti-apoptotic therapeutics.
 ...
PMID:The cytokine, granulocyte-macrophage colony-stimulating factor (GM-CSF), can deliver Bcl-XL as an extracellular fusion protein to protect cells from apoptosis and retain differentiation induction. 1731 27

The granulocyte-macrophage colony-stimulating factor (GM-CSF) is a hematopoietic cytokine able to regulate a variety of cell functions including differentiation of macrophages and granulocytes, dendritic cell development and the maintenance of homeostasis. It binds specifically to its receptor, which is composed of a cytokine-specific alpha-chain (GM-CSF receptor alpha-chain, GMRalpha) and a beta-chain shared with the receptors for interleukin-3 and interleukin-5. In this report, we present a comprehensive study of GMRalpha in the mouse. We have found that the mouse GMRalpha is polymorphic and alternatively spliced. In the absence of specific antibodies, we generated a novel chimeric protein containing the Fc fragment of human IgG1 coupled to mouse GM-CSF, which was able to specifically bind to GMRalpha and induce proliferation of GMRalpha-transduced Ba/F3 cells. We used this reagent to perform the first detailed FACS study of the surface expression of mouse GMRalpha by leucocytes. Highest expression was found on monocytes and granulocytes, and variable expression on tissue macrophages. The GM-CSF receptor in mice is specifically expressed by myeloid cells and is useful for the detection of novel uncharacterised myeloid populations. The ability to detect GM-CSF receptor expression in experimental studies should greatly facilitate the analysis of its role in immune pathologies.
 ...
PMID:Characterisation of the expression and function of the GM-CSF receptor alpha-chain in mice. 1769 71

An effective HIV-1 vaccine should ideally induce strong humoral and cellular immune responses that provide sterilizing immunity over a prolonged period. Current HIV-1 vaccines have failed in inducing such immunity. The viral envelope glycoprotein complex (Env) can be targeted by neutralizing antibodies to block infection, but several Env properties limit the ability to induce an antibody response of sufficient quantity and quality. We hypothesized that Env immunogenicity could be improved by embedding an immunostimulatory protein domain within its sequence. A stabilized Env trimer was therefore engineered with the granulocyte-macrophage colony-stimulating factor (GM-CSF) inserted into the V1V2 domain of gp120. Probing with neutralizing antibodies showed that both the Env and GM-CSF components of the chimeric protein were folded correctly. Furthermore, the embedded GM-CSF domain was functional as a cytokine in vitro. Mouse immunization studies demonstrated that chimeric Env(GM-CSF) enhanced Env-specific antibody and T cell responses compared with wild-type Env. Collectively, these results show that targeting and activation of immune cells using engineered cytokine domains within the protein can improve the immunogenicity of Env subunit vaccines.
 ...
PMID:A chimeric HIV-1 envelope glycoprotein trimer with an embedded granulocyte-macrophage colony-stimulating factor (GM-CSF) domain induces enhanced antibody and T cell responses. 2151 81