Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0023473 (chronic myeloid leukemia)
 18,916 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Most cytostatic drugs exert their effect on cells in active cell cycle. To improve the effect of cytostatic drugs we have tried, prior to treatment in vitro, to recruit tumor cells from G0 with growth factors. Leukemic cells from the bone marrows of 26 patients with AML and CML in blast crisis were incubated with G-CSF, GM-CSF and IL-3 for 24 h prior to incubation with cytostatic drugs. The cells were incubated with mitoxantrone, etoposide or daunorubicin for 1 h, or with Ara-C continuously. Prior to treatment, 4 patients with AML received GM-CSF for 24 h, after which blast cells from bone marrow were incubated with cytostatic drugs. After incubation with the cytostatic drugs, cells were cultured in a suspension culture for 4 d. The drug effect was determined with a bioluminescence ATP method. Leukemic cells were significantly stimulated by all three cytokines compared to an untreated control. GM-CSF and IL-3 increased the amount of cells 3- to 4-fold and G-CSF increased the amount 3 times compared to untreated cells. G-CSF significantly enhanced the cytotoxic effect of daunorubicin, mitoxantrone, etoposide and Ara-C by 20-40%, which GM-CSF and IL-3 showed a significantly increased toxicity for Ara-C only. Although the cytokines induced a higher percentage of cells killed with the cytostatic drugs, proliferation of the remaining cells resulted in an increased total number of cells from 1.5 to 3 times compared to the unstimulated incubations. We conclude that cytokines induce a higher level of toxicity of cytostatic drugs on leukemic cells, but the increased proliferation of the remaining cells may offset the clinical benefit.
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PMID:Effect of cytokines on the toxicity of cytostatic drugs on leukemic cells in vitro and in vivo. 859 80

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

Using chronic myelogenous leukemia (CML) as a model, we tested the hypothesis that cytokine-independent growth of leukemia cells results from aberrant activation of cytokine signaling pathways. The STAT5 (signal transducer and activator of transcription) protein, which is activated transiently in normal myeloid cells by cytokines such as GM-CSF (granulocyte-macrophage colony stimulating factor), was constitutively activated in cell lines derived from CML patients, even in the absence of GM-CSF. STAT5 was also activated in primary mouse bone marrow cells acutely transformed by the CML-specific BCR-ABL oncogene, but not by the serine kinase oncogene v-MOS. Reconstitution experiments in non-hematopoietic cells show that STAT5 activation by BCR-ABL occurs independent of cytokines. Results using BCR-ABL mutants which specifically uncouple connections to known signal transduction pathways show that STAT5 activation is kinase dependent and correlates directly with ability to confer cytokine independent growth in hematopoietic cells. BCR-ABL also activates JAK kinases, which may provide a mechanism for STAT activation. These findings are consistent with a role for STAT5 in hematopoietic transformation by BCR-ABL.
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PMID:Constitutive activation of STAT5 by the BCR-ABL oncogene in chronic myelogenous leukemia. 871 Mar 63

Twenty-five patients with hematologic malignancies were treated with busulfan (16 mg/kg) and cyclophosphamide (50 mg/kg x 3 days) as conditioning for bone marrow transplantation using marrow from serologically matched, DR locus genotypically identical unrelated donors. Previous studies of BuCy2 as conditioning for UD-BMT have reported a graft failure rate of up to 21% suggesting it may be insufficiently immunosuppressive in this setting. We elected not to use BuCy4 as it may have a higher incidence of extramedullary toxicity. In addition the patients received GM-CSF (500 mg/m2) from day 0, cyclosporine and short-course methotrexate (15 mg/m2 x 1, then 10 mg/m2 x 3) as GVHD prophylaxis and prophylactic ganciclovir at engraftment if either they or their donor were CMV antibody positive. The median age of the 25 patients was 41 years and the most common diagnosis was CML (76%). Seven patients were considered poor risk and eight males were recipients of marrow from female donors. Sixteen patients survive at a median of 435 days from transplant. The actuarial overall and disease-free survivals at 1 year in this group of older patients were 62 +/- 20% and 57 +/- 20% and 100-day survival was 70%. The engraftment rate was 100%; there have been no instances of secondary graft failure. Fifteen patients (60%) developed grade II-IV GVHD and 12 of 16 (75%) developed some chronic GVHD but only half of these were extensive. The performance status of survivors is good (median of 90); seven of 12 eligible patients are back at work. This study demonstrates that UD-BMT can be successfully performed in very closely HLA-matched older patients using a chemotherapy-only protocol and that low rates of severe acute GVHD can be achieved without T cell depletion.
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PMID:Unrelated donor bone marrow transplantation without T cell depletion using a chemotherapy only condition regimen. Low incidence of failed engraftment and severe acute GVHD. 872 53

Cell adhesion to the extracellular matrix is largely mediated by adhesion molecules of the integrin family and is often diminished upon oncogenic transformation. However, we show here that the chronic myelogenous leukemia oncogene Bcr/Abl has positive effects on VLA-4 and VLA-5 integrin function. The presence of Bcr/Abl in the GM-CSF- or IL-3-dependent hematopoietic cell lines MO7e, 32D, and BaF/3 enhanced cell binding to both soluble and immobilized fibronectin. The effect was due to enhanced function of the VLA-5 integrin fibronectin receptor and not to increased surface expression. In parallel, Bcr/Abl stimulated cell adhesion to the VLA-4 integrin ligand VCAM-1. Stimulation of VLA-5 function directly correlated with induction of Bcr/Abl tyrosine kinase activity in a temperature-sensitive kinase mutant. Thus, Bcr/Abl stimulates integrin-dependent cell adhesion, by a mechanism involving increased ligand binding, with the tyrosine kinase activity of Bcr/Abl likely playing a key role. Consistent with these results, hematopoietic precursor cells from chronic myelogenous leukemia patients also showed increased adhesion to fibronectin.
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PMID:Bcr/Abl expression stimulates integrin function in hematopoietic cell lines. 875 65

The growth factor of hematopoiesis, G-CSF and GM-CSF, are now extremely useful in stem cell transplantation (SCT). Their main indications are given in this short paper. They accelerate hematopoietic recovery and they reduce morbidity and mortality after autologous SCT. GM-CSF can protect from hematopoietic toxicity of Gancyclovir and can reduce the mortality related to autologous and allogeneic graft failure. The combination of GM-CSF, G-CSF and erythropoietin can replace autologous SCT after a high dose therapy. G and GM-CSF are used to mobilise peripheral stem cells and allow peripheral blood stem cell transplantation. G-CSF given after a chemotherapy is able to mobilise Philadelphia negative stem cells in chronic myelocytic leukemia patients. Finally allogeneic peripheral blood stem cell mobilised by G-CSF in healthy donor is now a new field of clinical trials.
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PMID:[Contribution of hematopoietic growth factors and especially in the context of grafts of hematopoietic stem cells]. 888 Nov 2

Juvenile chronic myelogenous leukemia (JCML) is a hematologic malignancy of monocyte-macrophage lineage in which leukemic progression is mediated in an autocrine manner by tumor necrosis factor (TNF-alpha), GM-CSF and possibly other growth factors. Cytogenetic data showing involvement of both erythroid and monocyte-macrophage lineages in the JCML leukemic clone, as well as an observed episode of B-lineage lymphoid blast crisis in JCML, has strengthened the thesis for a lympho-hematopoietic pluripotent stem cell origin for the disorder. To study this further, JCML CD34+ cells from bone marrow (BM) or spleen from six newly diagnosed patients were isolated and cultured in clonogenic assays with combinations of recombinant cytokines. Compared to control CD34+ cells, JCML cells from all patients showed an aberrant growth pattern restricted almost exclusively to the monocyte-macrophage lineage. Most of the clonogenic activity was seen in a subsorted population of CD34+, HLA-Dr- cells. Additionally, an exaggerated growth response to minute doses of GM-CSF that had no effect on control cells was observed with JCML CD34+ cells. Recloning ("self-renewal") of JCML CD34+ cells was also strongly promoted by GM-CSF. JCML colonies also formed spontaneously in the absence of exogenous cytokines but were augmented by GM-CSF, interleukin 1 and TNF-alpha, the latter feature not seen with control CD34+ cells from normal BM. The abnormal spontaneous growth pattern of CD34+ JCML cells could be suppressed directly in vitro by anti-TNF-alpha antibodies and anti-GM-CSF antibodies alone or in combination, and by soluble TNF-alpha receptors (sTNF-R:Fc), consistent with the notion that JCML CD34+ cells are stimulated by both cytokines in an autocrine manner. In malignant CD34+ cells from one patient, the cytogenetic marker monosomy 7 proved leukemic involvement of monocyte-macrophage, erythroid and B-lymphoid lineages. We conclude that CD34+ JCML cells of multilineage potential exhibit excessive and aberrant monocyte-macrophage colony formation, a property that was previously observed in JCML progenitors found in light density cell fractions. Thus, within the CD34+ cellular compartment is a subpopulation of JCML "stem" cells that accounts for the abnormal leukemic proliferative activity in this disease.
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PMID:Juvenile chronic myelogenous leukemia multilineage CD34+ cells: aberrant growth and differentiation properties. 894 26

Myeloproliferative disorders (MPD) are characterized by several common clinical and biological features, although at the molecular level, each disease entity exhibits distinct abnormalities. IFN-alpha exerts beneficial therapeutic effects in chronic myelogenous leukemia, polycythemia vera and essential thrombocythemia, resulting in control of hematopoietic hyperplasia and, in a minority of patients, in induction of cytogenetic remission. The mechanism of action of IFN-alpha in MPD is poorly defined. Recently published in vitro findings suggest that IFN-alpha interacts with the regulation of hematopoiesis by multiple ways. Its antiproliferative activity is well known for more than a decade, however, substantial growth inhibition is achieved only at relatively high concentrations. Defective adhesion of hematopoietic progenitor cells in CML to bone marrow stromal cells is corrected by IFN-alpha, which might expose CML progenitors to inhibitory cytokines produced by the bone marrow microenvironment. Recent work from our group demonstrated, that IFN-alpha potently interacts with the production of hematopoietic cytokines in bone marrow stromal cells. Expression of stimulatory cytokines, such as GM-CSF, G-CSF, IL-1 and IL-11 is inhibited by IFN-ct, whereas the production of negative regulators, such as IL-1RA and MIP-1 alpha, is stimulated. The combined action of IFN-alpha on paracrine expression of cytokines suggests an indirect antihematopoietic effect, which might contribute to its clinical activity in MPD.
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PMID:Influence of interferon-alpha on cytokine expression by the bone marrow microenvironment--impact on treatment of myeloproliferative disorders. 895 83

Recently various cytokines have been introduced into the clinic and have played important therapeutic roles in the treatment of hematological malignancies. Among these cytokines, I have focused on interferon (IFN) and granulocyte (G) or granulocyte-macrophage (GM) colony stimulating factor (CSF), which are currently the most useful cytokines, in this review. IFN-alpha has been approved for chronic myelogenous leukemia (CML), multiple myeloma and hairy cell leukemia. In addition, IFN-alpha has therapeutic potentials for low grade non-Hodgkin's lymphoma, cutaneous T cell lymphoma and adult T cell leukemia/lymphoma. Thus, IFN-alpha is one of the most useful and wide-ranging antitumor agents in hematological malignancies. Most striking effects have been studied in chronic phase CML. Cytogenetic responses are seen in 30-40% of the treated patients and a complete cytogenetic response can be seen in about 10%. Long-term survival can be expected in these patients. Considering the risk of graft-versus-host disease-associated mortality in allogeneic bone marrow transplantation, the category of treatment is difficult to choose in IFN-responsive patients. Elucidation of the antitumor mechanism of IFN, as a prototype for other biological response modifiers, may revolutionize cancer treatment. G- and GM-CSF (CSFs) have reduced the duration of neutropenia, incidence of infectious episodes and days of hospitalization following cancer chemotherapy or stem cell transplantation. CSFs have also been used to mobilize peripheral blood stem cells and to increase dose intensity of chemotherapeutic agents. Leukemic cells from many patients with acute myelogenous leukemia (AML) have surface receptors for CSFs and may proliferate in response to CSFs. However, several randomized studies showed that CSFs can be used safely and effectively in augmenting neutrophil recovery in patients with AML when given after induction chemotherapy. Various trials have been made to prime leukemic cells by CSFs to make them more susceptible to chemotherapy, but no convincing evidence has been obtained.
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PMID:Cytokine therapy for hematological malignancies. 899 Jun 22


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