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Query: UMLS:C0023418 (leukemia)
 93,477 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A novel hematopoietic growth factor for primitive hematopoietic progenitor cells, the ligand for the flt3/flk2 receptor, (FL), has been recently purified and its gene has been cloned. In the present study, we investigated the effects of FL on the proliferation and differentiation of normal and leukemic myeloid progenitor cells. We demonstrate that FL is a potent stimulator of the in vitro growth of granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-3 (IL-3), or G-CSF-dependent granulocyte-macrophage committed precursors from Lin- CD34+ bone marrow cells of normal donors. By contrast, FL does not affect the growth of erythroid-committed progenitors even in the presence of erythropoietin. The effect of FL on the proliferation and on the in vitro growth of clonogenic leukemic precursor cells was studied in 54 acute myeloid leukemia (AML) cases. Fresh leukemia blasts from 36 of 45 patients with AML significantly responded to FL without any relation to the French-American-British (FAB) subtype. FL stimulated the proliferation of leukemic blasts in a dose-dependent fashion. Synergistic activities were seen when FL was combined with G-CSF, GM-CSF, IL-3, or stem cell factor (SCF). FL as a single factor induced or increased significantly colony formation by clonogenic precursor cells from 21 of 24 patients with AML. In the presence of suboptimal and optimal concentrations of G-CSF, GM-CSF, IL3, SCF, or a combination of all factors, FL strongly enhanced the number of leukemic colonies (up to 18-fold). We also evaluated the induction of tyrosine phosphorylated protein on FL stimulation in fresh AML cells. We demonstrate that, on FL stimulation, a band of phosphorylated protein(s) of about 90 kD can be detected in FL-responsive, but not in FL-unresponsive cases. This study suggests that FL may be an important factor for the growth of myeloid leukemia cells, either as a direct stimulus or as a synergistic factor with other cytokines.
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PMID:Effects of human FLT3 ligand on myeloid leukemia cell growth: heterogeneity in response and synergy with other hematopoietic growth factors. 749 67

Somatostatin (SS) is a 14 amino acid peptide which is secreted by the hypothalamus and the pancreatic islets. It expresses antiproliferative activity in various organ systems, experiments have suggested effects of SS on hematopoietic cells. Here we present investigations regarding the effect of SS and its analog SMS 201-995 (SMS) on the in vitro proliferation of acute lymphoblastic leukemia (ALL; n = 7 cases), acute myeloid leukemia (AML; n = 21 cases) and chronic lymphocytic leukemia (CLL; n = 2 cases). Both SS and SMS inhibited spontaneous leukemic cell growth in approximately 1/3 of cases (i.e. 7/19). G-CSF stimulated AML cells were inhibited by SMS in 11/21 cases. AML cell proliferation induced by IL-3 or GM-CSF was suppressed in only 3/21 and 6/21 cases, respectively. In ALL cells, IL-7-induced proliferation was suppressed by SMS in 3/7 cases. The effect of SMS seemed to depend on the type of the hematopoietic growth factor, and on their concentrations. In fact, high concentrations of G-CSF could override SMS blocking completely. Colony formation by normal marrow progenitors and DNA synthesis by HL-60 and T11/65 leukemic cell lines were not affected by SMS. In conclusion, somatostatin may act as a negative regulator of the proliferative activity of human leukemia.
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PMID:Somatostatin and its cyclic octapeptide analog SMS 201-995 as inhibitors of proliferation of human acute lymphoblastic and acute myeloid leukemia. 750 Jun 46

In human long-term marrow cultures granulomonopoiesis is maintained for several weeks. Studies on granulomonocytic progenitors (CFU-GM) and their progeny have shown that survival, proliferation, differentiation and maturation of these cells are controlled by a set of glycoproteins, the colony-stimulating factors (CSFs) and the Steel factor. We have studied the expression of these factors using reverse transcriptase polymerase chain reaction (RT-PCR) in 17 adherent layers of normal bone marrow at 3, 5 or 7 weeks of culture. We have taken the 5637 bladder carcinoma cell line as a control for expression of GM-CSF, M-CSF, G-CSF and Steel factor, and PHA-activated T lymphocytes as a control for expression of multi-CSF (interleukin 3, IL-3). We have found that GM-CSF was expressed in the 17 adherent layers without induction by interleukin 1 beta (IL-1 beta). M-CSF was also detected in all cases, but in two early-stage (week 3 and week 5) cultures only after stimulation by IL-1 beta. G-CSF was detected in only 11 cases (three without IL-1 beta, and eight after addition of IL-1 beta). Steel factor was detected in 14 cases (ten without IL-1 beta, and four after addition of IL-1 beta). IL-3 was not detected even by means of nested RT-PCR. These data indicate in six late-stage (week 5 or week 7) cultures G-CSF messenger concentrations 10(3)-fold less than in 5637 control cells (for an identical amount of total cellular RNA). A similar conclusion may be drawn for Steel factor in three late-stage cultures. For IL-3 our negative results indicate a messenger concentration 10(5)-fold less than in activated T lymphocytes. These results suggest a crucial role for GM-CSF and M-CSF in the maintenance of granulomonopoiesis in human long-term cultures. The role of G-CSF and Steel factor may be more marginal. Eventually IL-2 may not be involved in the regulatory process.
Leukemia 1994 Mar
PMID:The detection of colony-stimulating factors and steel factor in adherent layers of human long-term marrow cultures using reverse-transcriptase polymerase chain reaction. 751 Mar 57

A novel human CD7-positive leukemia cell line (HSM911) derived from the peripheral blood of a patient with acute myelogenous leukemia (AML) was studied for its cellular and biological characterization. Proliferation assay using a variety of cytokines demonstrated that the HSM911 cells proliferate in response to recombinant granulocyte-macrophage-colony stimulating factor (rGM-CSF), recombinant Interleukin-3 (rIL-3) and recombinant stem cell factor (rSCF), but do not in response to recombinant granulocyte-colony stimulating factor (rG-CSF), natural macrophage-colony stimulating factor (M-CSF), rIL-1, rIL-2, rIL-4, rIL-5, rIL-6 or recombinant erythropoietin (rEpo). Polyclonal anti-GM-CSF antibody and polyclonal anti-IL-3 antibody blocked the proliferation of HSM911 stimulated with rGM-CSF and rIL-3, respectively. HSM911 maintained in the presence of rGM-CSF expressed the CD7, CD13, CD33, CD34, CD41a, HLA-DR, VLA1-VLA5, CD11a, CD54, CD44 and LAM1. These findings suggest that HSM911 might be of multipotent progenitor cell origin. GM-CSF receptors and rIL-3 receptors expressed on this cell line were simultaneously suppressed by rGM-CSF or rIL-3, whereas only IL-3 receptors were down-modulated by rSCF. Treatment with 12-o-tetradecanoyl-phorbol-13-acetate (TPA) induced the differentiation of HSM911 cells into macrophage-like cells but not erythroblasts, megakaryocytes or lymphocytes. Interferon-gamma and transforming growth factor-beta (TGF-beta) suppressed the proliferation of HSM911 cells in a dose dependent manner. HSM911 was relatively resistant against anti-cancer drugs compared with fresh AML cells and other leukemic cell line. HSM911 is a useful tool for analyzing CD7-positive acute myelogenous leukemia.
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PMID:[Cellular and biological characterization of CD7-positive acute leukemia cells--an investigation of the established cell line, HSM911]. 752 34

The prognosis for patients with primary breast cancer involving multiple axillary lymph nodes is poor. Only about 30% of patients remain disease-free at 5 years from diagnosis despite surgery, conventional-dose chemotherapy, and radiation therapy. In nonrandomized studies, the use of high-dose chemotherapy as consolidation therapy after standard-dose induction chemotherapy has resulted in an apparent improvement in disease-free survival rates to over 70%. These results have prompted the National Cancer Institute to sponsor large-scale, multicenter, randomized comparative trials of this strategy. This Intergroup Study (Cancer and Leukemia Group B 9082, Southwest Oncology Group 9114, and National Cancer Institute of Canada MA13) compares two treatment strategies in women with primary breast cancer involving 10 or more axillary lymph nodes. Arms A and B are identical in the use of four cycles of conventional therapy with cyclophosphamide and doxorubicin and fluorouracil, radiation therapy, and tamoxifen. The only difference between the two arms is the dose intensity of the cyclophosphamide, cisplatin, and carmustine given following conventional adjuvant treatment. Arm A dictates bone marrow, peripheral blood stem cell, and hematopoietic growth factor support and frequently requires a prolonged hospital stay with high resource utilization. Arm B, with its less dose-intensive therapy, requires considerably less support to apply the treatment. Because of the high cost of this therapy and the requirement for technology-intensive support, there has been considerable interest in economic outcome assessments.
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PMID:Randomized, comparative study of high-dose (with autologous bone marrow support) versus low-dose cyclophosphamide, cisplatin, and carmustine as consolidation to adjuvant cyclophosphamide, doxorubicin, and fluorouracil for patients with operable stage II or III breast cancer involving 10 or more axillary lymph nodes (CALGB Protocol 9082). Cancer and Leukemia Group B. 757 4

Oncostatin M (OM) is structurally and functionally related to a subclass of hematopoietic cytokines including leukemia-inhibitory factor (LIF), ciliary neurotrophic factor (CNTF), granulocyte colony-stimulating factor (G-CSF), and interleukin-6 (IL-6). Using human endothelial cells (HEC) as a model for cytokine regulation of hematopoietic growth factor expression, we tested OM as an inducer of colony-stimulating activity. Colony-forming cell assays supplemented with culture supernatants from OM-treated HEC contained a threefold increase in colony-forming unit granulocyte-macrophage colonies. Specific immunoassay (enzyme-linked immunosorbent assay) of culture supernatants indicated that OM treatment of HEC resulted in a dose- and time-dependent increase in the accumulation of G-CSF and granulocyte-macrophage CSF (GM-CSF) (> 28-fold). The ED50 for OM induction of G-CSF and GM-CSF protein expression was 17 and 7 pmol/L, respectively. Increased protein expression was associated with a similar increase in steady-state expression of G-CSF and GM-CSF mRNA. Furthermore, a period of 12 to 24 hours elapsed before there were measurable increases in CSF expression, suggesting that OM may stimulate CSF production through a mechanism requiring the synthesis or activation of a secondary mediating factor or pathway. These findings provide the first evidence that OM may regulate myelopoiesis by inducing the cellular expression of hematopoietic growth factors.
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PMID:Regulation of granulocyte colony-stimulating factor and granulocyte-macrophage colony-stimulating factor expression by oncostatin M. 768 88

We have recently shown that conservation and differentiation of primitive human hematopoietic progenitors in in vitro long-term bone marrow cultures (LTBMC) occurs to a greater extent when hematopoietic cells are grown separated from the stromal layer than when grown in direct contact with the stroma. This finding suggests that hematopoiesis may depend mainly on soluble factors produced by the stroma. To define these soluble factors, we examine here whether a combination of defined early-acting cytokines can replace soluble stroma-derived biologic activities that induce conservation and differentiation of primitive progenitors. Normal human Lineage-/CD34+/HLA-DR- cells (DR-) were cultured either in the absence of a stromal layer ("stroma-free") or in a culture system in which DR- cells were separated from the stromal layer by a microporous membrane ("stroma-noncontact"). Both culture systems were supplemented three times per week with or without cytokines. These studies show that culture of DR- cells for 5 weeks in a "stroma-free" culture supplemented with a combination of four early acting cytokines (Interleukin-3 [IL-3], stem cell factor [SCF], leukemia-inhibitory factor [LIF], and granulocyte colony-stimulating factor [G-CSF]) results in a similar cell expansion as when DR- cells are cultured in "stroma-noncontact" cultures supplemented with the same cytokines. However, generation of committed progenitors and conservation of the more primitive long-term bone marrow culture initiating cells (LTBMC-IC) was far superior in "stroma-noncontact" cultures supplemented with or without IL-3 than in "stroma-free" cultures supplemented with IL-3 alone or a combination of IL-3, LIF, G-CSF, and SCF. These studies indicate that human BM stroma produces soluble factors that can either alone or in synergy with defined cytokines (1) conserve primitive LTBMC-IC, (2) induce early differentiation of a fraction of the primitive progenitors, and (3) prevent their terminal differentiation. We show here that these stroma-derived factors are not likely to be the known early acting cytokines IL-3, SCF, LIF, or G-CSF. Characterization of the stroma-derived factor(s) may have important implications for clinically relevant studies, such as in vitro stem cell expansion in cancer treatment and gene therapy.
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PMID:Soluble factor(s) produced by human bone marrow stroma increase cytokine-induced proliferation and maturation of primitive hematopoietic progenitors while preventing their terminal differentiation. 769 Dec 46

We investigated hematopoietic growth factor (HGF) and cytokine gene expression in the bone marrow (BM) and peripheral blood (PB) of healthy individuals as a starting point for delineating the physiologic role of cytokines in steady state hematopoiesis. BM biopsy specimens and PB samples from 7 healthy individuals were analyzed by polymerase chain reaction amplification of reverse-transcribed RNA using gene-specific primer sets. Consistent gene expression in the BM of all 7 individuals was detected for macrophage colony-stimulating factor (CSF), stem cell factor, interleukin-6 (IL-6), IL-7, erythroid-potentiating factor, erythroid-differentiating factor, and insulinlike growth factor 1, all cytokines with reported direct stimulatory effects on in vitro hematopoiesis. Of these, erythroid-potentiating factor and erythroid-differentiating factor appeared to be the only stimulating factors that were also expressed in the PB. Among the cytokines with inhibitory effects on in vitro hematopoiesis IL-4, tumor necrosis factor-alpha (TNF-alpha), TNF-beta, transforming growth factor-beta, and macrophage inflammatory protein-1 alpha were expressed in the BM of the 7 individuals. Except for TNF-alpha, the latter cytokines were also expressed in the PB. Consistent expression in the BM and PB of all tested individuals was also observed for IL-1 beta, IL-1 receptor antagonist, and IL-1 beta converting enzyme, which are all members of the IL-1 family with a possible indirect effect on hematopoiesis. Remarkably, no expression of granulocyte CSF, granulocyte-macrophage CSF, and IL-3 was found in the BM or PB of all investigated individuals (n = 15). This was also the case for IL-1 alpha, IL-2, IL-5, IL-9, IL-12, IL-13, leukemia-inhibiting factor, interferon-gamma, and inhibin. Weak IL-8 and IL-10 expression was found in the BM and/or PB of a minority of investigated individuals. These findings provide insight into which cytokines or HGFs potentially are involved in the autocrine or paracrine regulation of in vivo steady state hematopoiesis. The absence of expression of granulocyte CSF, granulocyte-macrophage CSF, and IL-3 in the BM of healthy individuals implicates that it is highly unlikely that these HGFs are involved in the autocrine or paracrine regulation of constitutive hematopoiesis.
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PMID:Constitutive in vivo cytokine and hematopoietic growth factor gene expression in the bone marrow and peripheral blood of healthy individuals. 771 76

Receptors of most hematopoietic growth factors are structurally related and grouped in the hematopoietin or cytokine receptor superfamily. In this paper, we will first review the general principles of hematopoietin receptor complex formation and cytoplasmic signaling. Subsequently, the significance of defective hematopoietic growth factor receptors for the development of hematological diseases will be discussed.
Leukemia 1995 Apr
PMID:Hematopoietic growth factor receptors: structure variations and alternatives of receptor complex formation in normal hematopoiesis and in hematopoietic disorders. 772 84

Both structure-function analysis of hematopoietic growth factor receptors and identification of novel signal transduction molecules have provided new insights into the processes involved in signal transmission pathways engaged by hematopoietic growth factors. These investigations have pointed to the importance of post-translational modifications of pre-existing proteins, in particular tyrosine phosphorylation, in transmitting signals and thereby linking extracellular signals to the activation of nuclear effector molecules which govern gene expression. These observations not only contribute to our understanding of the pleiotropism and redundancy ascribed to hematopoietic growth factors, but also help to trace some of the molecules conferring signal specificity. It is to be expected that this rapidly evolving research field will provide us with a significant collection of new findings in the near future and that the precise understanding of the processes involved in ligand-binding and signal transmission will also stimulate the development of novel therapeutic drugs affecting these processes. This article gives a short overview on the role of tyrosine kinases and their substrates in signal transmission processes initiated by hematopoietic growth factors.
Leukemia 1995 May
PMID:The role of tyrosine kinases and their substrates in signal transmission of hematopoietic growth factors: a short review. 776 36


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