Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.7.10.1 (ERK)
95,504 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Peripheral blood mononuclear cells from seventeen patients with primary myelodysplastic syndromes (MDS) in advanced stage were enriched for blasts and tested for (1) karyotype, (2) genomic configuration and (3) expression of IL-3, GM-CSF, FMS and EGR-1 genes which are all located on the long arm of chromosome 5. The expression of the M-CSF gene, that has been recently reassigned to the short arm of chromosome 1 (lp), was also investigated. Aims of the study were to (1) assess the potential role of the expression of these genes in the maintenance and expansion of the neoplastic clones and (2) search for constitutional losses or rearrangements of one allele followed by a deletion of the second allele of the same genes in the leukemic cells. The latter issue was investigated by comparing, in 8 cases, constitutive DNA from skin fibroblasts with leukemic DNA. Eleven of the 17 patients had abnormal karyotypes. The M-CSF gene was expressed in 6 cases and the FMS and the EGR-1 genes were expressed in 2 of the latter cases. An autocrine mechanism of growth could be hypothesized only for the 2 patients whose cells expressed both the M-CSF and FMS genes. No germline changes or rearrangements were observed in any of the genes studied. Thus, deregulation of genes encoding for certain hemopoietic growth factors or receptors does not seem to represent a major mechanism of MDS progression.
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PMID:Expression and genomic configuration of GM-CSF, IL-3, M-CSF receptor (C-FMS), early growth response gene-1 (EGR-1) and M-CSF genes in primary myelodysplastic syndromes. 785 91

The novel hematopoietic growth factor FLT3 ligand (FL) is the cognate ligand for the FLT3, tyrosine kinase receptor (R), also referred to as FLK-2 and STK-1. The FLT3R belongs to a family of receptor tyrosine kinases involved in hematopoiesis that also includes KIT, the receptor for SCF (stem cell factor), and FMS. the receptor for M-CSF (macrophage colony- stimulating factor). Restricted FLT3R expression was seen on human and murine hematopoietic progenitor cells. In functional assays recombinant FL stimulated the proliferation and colony formation of human hematopoietic progenitor cells, i.e. CD34+ cord and peripheral blood, bone marrow and fetal liver cells. Synergy was reported for co-stimulation with G-CSF (granulocyte-CSF). GM-CSF (granulocyte-macrophage CSF), M-CSF, interleukin-3 (IL-3), PIXY-321 (an IL-3/GM-CSF fusion protein) and SCF. In the mouse, FL potently enhanced growth of various types of progenitor/precursor cells in synergy with G-CSF, GM-CSF, M-CSF, IL-3, IL-6, IL-7, IL-11, IL-12 and SCF. The well-documented involvement of this ligand-receptor pair in physiological hematopoiesis brought forth the question whether FLT3R and FL might also have a role in the pathobiology of leukemia. At the mRNA level FLT3R was expressed by most (80-100%) cases of AML (acute myeloid leukemia) throughout the different morphological subtypes (MO-M7), of ALL(acute lymphoblastic leukemia) of the immunological subtypes T-ALL and BCP-ALL (B cell precursor ALL including pre-pre B-ALL, cALL and pre B-ALL), of AMLL (acute mixed-lineage leukemia), and of CML (chronic myeloid leukemia) in lymphoid or mixed blast crisis. Analysis of cell surface expression of FLT3R by flow cytometry confirmed these observations for AML (66% positivity when the data from all studies are combined), BCP-ALL (64%) and CML lymphoid blast crisis (86%) whereas less than 30% of T-ALL were FLT3R+. The myeloid, monocytic and pre B cell type categories also contained the highest proportions of FLT3R+ leukemia cell lines . In contrast to the selective expression of the receptor, FL expression was detected in 90-100% of the various cell types of leukemia cell lines from all hematopoietic cell lineages. The potential of FL to induce proliferation of leukemia cells in vitro was also examined in primary and continuously cultured leukemia cells. The data on FL-stimulated leukemia cell growth underline the extensive heterogeneity of primary AML and ALL samples in terms of cytokine-inducible DNA synthesis that has been seen with other effective cytokines. While the majority of T-ALL (0-33% of the cases responded proliferatively; mean 11%) and BCP-ALL (0-30%; mean 20%) failed to proliferate in the presence of FL despite strong expression of surface FLT3R, FL caused a proliferative response in a significantly higher percentage of AML cases (22-90%; mean 53%). In the panel of leukemia cell lines examined only myeloid and monocytic growth factor- dependent cell lines increased their proliferation upon incubation with FL, whereas all growth factor-independent cell lines were refractory to stimulation. Combinations of FL with G-CSF, GM-CSF, M-CSF, IL-3, PIXY- 321 or SCF and FL with IL-3 or IL-7 had synergistic or additive mitogenic effects on primary AML and ALL cells, respectively. The potent stimulation of the myelomonocytic cell lines was further augmented by addition of bFGF (basic fibroblast growth factor), GM-CSF, IL-3 or SCF. The inhibitory effects of TGF-beta 1 (transforming growth factor-beta 1) on FL- supported proliferation were abrogated by bFGF. Taken together, these results demonstrate the expression of functional FLT3R capable of mediating FL- dependent mitogenic signaling in a subset of AML and ALL cases further underline the heterogeneity of AML and ALL samples in their proliferative response to cytokine.
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PMID:Expression of FLT3 receptor and response to FLT3 ligand by leukemic cells. 861 33

Characteristic of Philadelphia (Ph)+ chronic myelogenous leukemia (CML) is the presence of the chimeric BCR/ABL (p210) protein possessing elevated protein tyrosine kinase activity relative to the normal c-abl tyrosine kinase. Our previous studies demonstrated subtle differences in the growth, phenotypic and morphologic characteristics of the most primitive subpopulations of primary lin-Ph+ chronic phase CML blasts and comparable primary lin- normal blasts. Recently, in comparing proteins phosphorylated on tyrosine in these cell populations, we reported a prominent 62 kDa phosphotyrosyl (P-tyr) protein constitutively present in primary primitive lin- CML chronic phase blasts which was virtually undetectable in primary primitive lin- normal blasts. In the present studies, we demonstrate that this P-tyr p62 from primary primitive lin- chronic phase CML blasts co-immunoprecipitates with ras-GAP. Furthermore, in addition to the p210 protein, we show in whole cell lysates the presence of other clearly consistent but less prominent P-tyr proteins with molecular weights of approximately 155, 140, 110, 55 and 45 kDa as well as more minor P-tyr proteins of approximately 190, 85, 52, 42 and 39 kDa constitutively present in primary primitive lin- chronic phase CML blasts. In analyzing proteins tyrosine phosphorylated in primary primitive lin- normal blasts in response to various hematopoietic growth factors, we found a striking similarity in the phosphorylation of four major (approximately 140, 110, 62 and 56 kDa) and three minor (approximately 51, 45 and 42 kDa) P-tyr proteins after stimulation with c-kit ligand and the P-tyr proteins constitutively phosphorylated in primary primitive lin- chronic phase CML blasts. Other growth factors tested (ie GM-CSF, G-CSF, IL-3, FLT3 ligand and EPO) were much less active or stimulated phosphorylation of other proteins. It is provocative that at least seven proteins rapidly and transiently phosphorylated on tyrosine in the c-kit ligand signal transduction pathway in lin- normal blasts may be constitutive substrates for the p210 activated tyrosine kinase in comparable lin- chronic phase CML blasts. In addition, it is intriguing that some of the biological effects on hematopoietic progenitors attributed to the c-kit ligand may be similar to some of the observed biological consequences of the p210 protein, including survival and expansion of a more mature stem cell population, probably at the time of lineage commitment rather than at the level of the earliest self-renewing stem cell.
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PMID:c-kit ligand stimulates tyrosine phosphorylation of a similar pattern of phosphotyrosyl proteins in primary primitive normal hematopoietic progenitors that are constitutively phosphorylated in comparable primitive progenitors in chronic phase chronic myelogenous leukemia. 863 31

Macrophage-stimulating protein (MSP), originally identified as an inducer of murine resident macrophage responsiveness to chemoattractants, is a ligand for human RON/murine STK receptor protein tyrosine kinases. Since STK was cloned from populations enriched for hematopoietic stem cells, we initiated studies on the effects of MSP on colony formation by granulocyte-macrophage (CFU-GM), erythroid (BFU-E), and multipotential (CFU-GEMM) myeloid progenitor cells. MSP alone had no colony stimulating activity. However, MSP caused about a 50% suppression of CFU-GM colony formation induced by synergistic combinations of SLF or Flt-L plus GM-CSF, G-CSF, or IL-3 and of BFU-E and CFU-GEMM colonies induced by SLF or Flt3-L plus Epo or Epo and IL-3. In contrast, MSP had no effect on progenitors stimulated by one growth factor. MSP also suppressed colony formation by stimulated cord blood progenitors, but only after preinduction to a rapidly cycling state. It was previously reported that several members of the chemokine family synergistically suppress myeloid progenitor proliferation. Likewise, synergistic suppression was observed when MSP was paired with VEGF, MIP-1 alpha, IL-8, PF4, MCP-1, IP-10, or ENA-78, or when VEGF was paired with the chemokines; and the required MSP concentration was more than 100-fold less than for MSP alone. Additionally, MSP or VEGF inhibited proliferation of the human myeloid growth factor-dependent cell line, M07e, but a sustained effect required multiple additions over time. At the least, some of the MSP suppressive effects on myeloid progenitors, as assessed on single isolated CD34 marrow cells, appeared to be directly on the progenitors; sustained additions of MSP were required to see this effect. The suppressive action of MSP and its synergism with proteins of the chemokine family may be of relevance to regulation of blood cell production.
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PMID:Macrophage-stimulating protein, a ligand for the RON receptor protein tyrosine kinase, suppresses myeloid progenitor cell proliferation and synergizes with vascular endothelial cell growth factor and members of the chemokine family. 869 17

Two methods to generate human dendritic cells from hematopoietic precursor cells in peripheral blood have recently been published. One approach utilizes the rare CD34+ precursors and GM-CSF plus TNF-alpha. The other method makes use of the more abundant CD34- precursor population and GM-CSF plus IL-4. Here we report a method that is based on the latter approach. However, the GM-CSF and IL-4 treated cells are not stable mature dendritic cells, e.g., the characteristic morphology and nonadherence of dendritic cells is lost if the cytokines are removed. We describe the need for a monocyte-conditioned medium to generate fully mature and stable dendritic cells. This is achieved by adding a 3 day 'maturation culture' to the initial 6-7 day culture in the presence of GM-CSF and IL-4. Macrophage-conditioned medium contains the critical maturation factors. Mature dendritic cells are defined by their pronounced display of motile cytoplasmic processes ('veils'), their high capacity to induce proliferative responses in resting T cells, particularly in naive umbilical cord T cells, their down-regulated antigen processing ability, and their characteristic phenotype: expression of CD83, high levels of MHC molecules and CD86, lack of CD115 and perinuclear dot-like CD68 staining. These features are stable for at least 3 days upon withdrawal of cytokines and conditioned media. IL-4 can be replaced by IL-13. When CD34+ progenitors are depleted from blood, there is only a minor reduction in the yield of dendritic cells by this method. We have adapted the method to consider several variables that are pertinent to clinical use, including a change from fetal calf serum to human plasma and to media approved for clinical use like X-VIVO or AIM-V. 1% plasma and RPMI 1640 are currently optimal. Additional reagents used for cell culture (Ig. cytokines) and cell separation (immunomagnetic beads) are approved for or already used in clinical applications. For 40 ml blood, the yield is 0.8-3.3 x 10(6) mature dendritic cells as defined by the expression of the new dendritic cell-restricted marker CD83. CD83+ cells constitute between 30 and 80% of all cells recovered at the end of the culture period. Yields can be enhanced up to six-fold if the blood donors are pretreated with G-CSF. Stable, mature dendritic cells generated by this method should be a powerful tool for active immunotherapy.
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PMID:Generation of mature dendritic cells from human blood. An improved method with special regard to clinical applicability. 884 52

Peripheral blood stem cells (PBSC) are used increasingly for autotransplantation in the treatment of acute leukemia, lymphoma, multiple myeloma, solid tumors such as ovarian and breast carcinoma. They are collected by leukaphereses during rapid hematopoietic recovery, following cytotoxic chemotherapy with or without administration of hematopoietic growth factors. We studied the clonogenic and cytokine-mediated expansion potential of CD34+ cells from mobilized PBSC. Low density mononuclear cells were processed using the CEPRATE LC CD34 KIT (CellPro). CD34+ purified cells, were cultured in suspension with 6 combined hematopoietic growth factors (IL1beta, IL3, IL6 at 100 U/ml and G-CSF, GM-CSF and stem cell factor at 10 ng/ml of each) for up to four weeks. Every week, cells were counted and CFU-GM assay was performed in a methylcellulose based medium. We have analysed the percentage of cells bearing CD34, CD33, CD38, HLA-DR, CD45RA, CD45RO antigens. Our results showed, that CD34+ cells were obtained with a purity of 92 +/- 2.3% and a yield of 71 +/- 10.7%. The majority co-expressed CD33 (57.76 +/- 34.16%) and CD38 (62.2 +/- 34%) antigens. These culture conditions, are necessary to obtain a fold increase of nucleated cells (377 fold at week 4), of CFU-GM progenitors (41.2 fold at week 3) and of CD34+ cell absolute number (10 fold at week 1) with an important differentiation of progenitors in particular myeloid progenitors.
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PMID:Peripheral blood CD34+ cells: method of purification and ex vivo expansion. 890 32

FLT3 ligand (FL) is a recently described hematopoietic growth factor that stimulates the proliferation and differentiation of hematopoietic progenitors. We have investigated the effect of FL on murine hematopoiesis and dendritic cell (DC) generation and accumulation in lymphoid tissues and liver in vivo and in vitro evaluating the morphologic, phenotypic, and functional characteristics of these DC. We have observed extramedullary hematopoiesis in the mouse spleen with all lineages of hematopoietic cells represented after the administration of FL. Injection of FL results in a time-dependent and reversible accumulation of DC in the spleen, bone marrow, lymph nodes, and liver. Both flow cytometry and immunohistochemistry revealed a significant accumulation of DC in these tissues. Results of mixed leukocyte reaction suggested that these cells, isolated from murine bone marrow or spleen, were active as antigen presenting cells. Furthermore, cultivation of splenic and marrow cells with GM-CSF and IL-4 gave rise to large numbers of functionally active mature DC. Thus, the results of this study suggest that FL is a promising growth factor that stimulates the generation of large number of DC and may be a useful cytokine for the immunotherapy of cancer.
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PMID:FLT3 ligand induces the generation of functionally active dendritic cells in mice. 926 1

The 9;22 chromosomal translocation characteristic of CML results in a fused bcr/abl gene and an abnormal fusion protein, p210bcr/abl. Relative to normal c-abl, p210bc1/abl has elevated tyrosine kinase activity that is essential for its transforming activity. We recently reported a prominent 62 kDa GAP-associated P-tyr protein and five additional consistent but less prominent P-tyr proteins as well as five more minor P-tyr proteins that are constitutively tyrosine phosphorylated in primary primitive lineage negative (lin-) chronic phase CML blasts but not in comparable primary lin- normal blasts. The GAP-associated p62 protein has now been purified, sequenced and its gene has been cloned; it is a previously unidentified protein and is currently being characterized. In analyzing P-tyr proteins in primary lin- normal blasts in response to various hematopoietic cytokines, we found a striking similarity in the tyrosine phosphorylation of four major and three minor proteins after stimulation with c-kit ligand (KL) and the P-tyr proteins that are constitutively phosphorylated in primary primitive lin- chronic phase CML blasts. Other cytokines tested (ie GM-CSF, G-CSF, IL-3, FLT3 ligand, TPO, EPO) were much less active or stimulated phosphorylation of other proteins. KL/c-kit and bcr/abl have some similar activities including enhancing survival and expansion of hematopoietic progenitor cells, probably acting primarily on early progenitors at the time of lineage commitment rather than on self-renewing stem cells. Activation of growth factor receptors promote a cascade of protein phosphorylations that can ultimately result in a wide range of cellular responses. Sustained activation of discrete signaling pathways in some types of cells results in differentiation, whereas transient activation instead causes a proliferative response; in other cell types, the converse is true. It may be postulated that stem cells and primitive progenitors are at a particularly susceptible stage of development that renders them especially responsive to sustained bcr/abl-induced phorphorylation of a number of signaling proteins that are components of critical regulatory pathways, including c-kit. The affected pathways control and coordinate multiple diverse cell processes including proliferation, differentiation, maturation and apoptosis, processes that are normally tightly regulated and integrated. Perturbation of these key pathways in primitive progenitors would be expected to seriously disrupt orderly hematopoiesis and could also explain the multiple subtle pleiotropic biological abnormalities characteristically observed in later maturing CML compartments that we have collectively designated 'discordant maturation'. The true situation is undoubtedly very complex and involves interaction of multiple cytokines and signaling pathways that we are now trying to define. Constitutive downstream activation of critical pathways in susceptible early progenitors that normally require KL or other factors for activation could explain most if not all features of the disease.
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PMID:New understanding of the pathogenesis of CML: a prototype of early neoplasia. 952 44

There are relatively few monoclonal antibodies (mAb) that have been characterized for their applicability in studies on the immune system of various nonhuman primates. In the present study, we identified a large number of mAb that can be used in future immunological studies in three different nonhuman primates, i.e., chimpanzees, rhesus macaques, and squirrel monkeys. The reactivity of 161 anti-human mAb to T-cell antigens and cytokine receptors were tested on peripheral blood mononuclear cells (PBMC) from the three primate species by flow cytometric analysis. A total of 105 (65%), 73 (45%), and 68 (42%) antibodies reacted with PBMC from chimpanzees, rhesus macaques, and squirrel monkeys, respectively. Out of the 161 mAb, 38 reacted with all three species and 112 reacted with one or two of the species. No specific reaction was observed with mAb to receptors to GM-CSF, 4-1BB, FLT3, FLX2, common beta-chain, IL-1 (type I receptor), and IL-8.
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PMID:Flow cytometric analysis on reactivity of human T lymphocyte-specific and cytokine-receptor-specific antibodies with peripheral blood mononuclear cells of chimpanzee (Pan troglodytes), rhesus macaque (Macaca mulatta), and squirrel monkey (Saimiri sciureus) 987 63

The class I IgG receptor (Fc gamma RI or CD64 receptor), which is present on key cytotoxic effector cells, has been shown to initiate the destruction of tumor cells in vitro and has been hypothesized to play a role in the destruction of antibody-coated cells such as platelets in idiopathic thrombocytopenia purpura (ITP). This overview summarizes the clinical experience with CD64-directed immunotherapy in cancer patients with the bispecific antibodies MDX-447 [humanized Fab anti-CD64 x humanized Fab anti-(epidermal growth factor receptor, EGFR)] and MDX-H210 (humanized Fab anti-DC64 x Fab anti-HER2/neu), and with the anti-CD64 monoclonal antibody (mAB) MDX-33 (H22) in the modulation of monocyte CD64 in vivo. In an ongoing phase I/II open-label trial with progressive dose escalation (1-15 mg/m2), patients with treatment refractory EGFR-positive cancers (renal cell carcinoma (RCC), head and neck, bladder, ovarian, prostate cancer and skin cancer) are treated weekly with intravenous MDX-447, with and without granulocyte-colony-stimulating factor (G-CSF). MDX-447 has been found to be immunologically active at all doses, binding to circulating monocytes and neutrophils (when given with G-CSF), causing monocytopenia and stimulating increases in circulating plasma cytokines. MDX-447 is well tolerated, the primary toxicities being fever, chills, blood pressure lability, and pain/ myalgias. Of 36 patients evaluable for response, 9 have experienced stable disease of 3-6 month's duration. The optimal dose and the maximal tolerated dose (MTD) have yet to be defined; dose escalation continues to define better the dose, toxicity, and the potential therapeutic role of this bispecific antibody. Three MDX-H210 phase II trials are currently in progress, all using the intravenous dose of 15 mg/m2 given with granulocyte/macrophage (GM-CSF). These consist of one trial each in the treatment of RCC patients, patients with prostate cancer, and colorectal cancer patients, all of whom have failed standard therapy. At the time of writing, 11 patients have been treated in these phase II trials. Four patients have demonstrated antitumor effects. Patients demonstrating responses include 2 with RCC and 2 with prostate cancer. One RCC patient has had a 54% reduction in size of a hepatic metastatic lesion and the other has had a 49% decrease in the size of a lung metastasis with simultaneous clearing of other non-measurable lung lesions. Regarding the two patients with prostate cancer, one has had a 90% reduction in serum prostate-specific antigen (PSA; 118-11 ng/ml), which has persisted for several months; the other patient with prostate has had a 70% reduction of serum PSA (872 ng/ml to 208 ng/ml) within the first month of treatment. Both patients have also demonstrated symptomatic improvement. In a completed phase I and in ongoing phase I/II clinical trials, patients with treatment-refractory HER2/neu positive cancers (breast, ovarian, colorectal, prostate) have been treated with MDX-H210, which has been given alone and in conjunction with G-CSF, GM-CSF, and interferon gamma (IFN gamma). These trials have been open-label, progressive dose-escalation (0.35-135 mg/m2) studies in which single, and more often, multiple weekly doses have been administered. MDX-H210 has been well tolerated, with untoward effects being primarily mild-to-moderate flu-like symptoms. The MTD has not yet been defined. MDX-H210 is immunologically active, binding to circulating monocytes, causing monocytopenia, as well as stimulating increases in plasma cytokine levels. Furthermore, some patients have evidence of active antitumor immunity following treatment with MDX-210. Antitumor effects have been seen in response to MDX-H210 administration; these include 1 partial, 2 minor, and 1 mixed tumor response; 15 protocol-defined stable disease responses have occurred. (ABSTRACT TRUNCATED)
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PMID:Clinical experience with CD64-directed immunotherapy. An overview. 943 76


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