Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0023418 (leukemia)
 93,477 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Recently, in-frame internal tandem duplications have been reported within the regions coding for the juxtamembrane through the first tyrosine kinase domain of the Flt3 gene. These duplications have been reported to lead to autophosphorylation of the receptor. In this study we investigated the effect of such mutations in the Flt3 gene on the in vitro proliferation of human acute myeloid leukemia cells. The mutations were detected in 10 out of 59 AML bone marrow samples analyzed and were not restricted to a specific FAB class or cytogenetic aberration. PCR analysis of those samples showed all mutations to be present in exon 11 of the gene. Whilst samples without a mutation of the Flt3 gene showed an increased cell production in response to either IL-3 and G-CSF or IL-6, SCF, TPO and Flt3L in long-term stroma supported cultures, mutant samples failed to do so. As we could not find a relationship between the absence of a response and either FAB class or cytogenetic aberrations, we interpret these results as an indication that the internal tandem duplications in the Flt3 gene are the prime cause of this unresponsiveness. Although our study does not explain the mechanism by which these mutations cause this unresponsiveness it does suggest that AML cells need a wild-type Flt3 for optimal in vitro proliferation.
Leukemia 1999 Jul
PMID:Human acute myeloid leukemia cells with internal tandem duplications in the Flt3 gene show reduced proliferative ability in stroma supported long-term cultures. 1040 Apr 23

Soluble factors produced by human marrow stroma or the murine marrow derived M2-10B4 cell line support ex vivo maintenance for 5-8 weeks of 50% of human long-term culture initiating cells (LTC-IC). As the AFT024 cell line supports LTC-IC cultured in contact conditions better than M2-10B4 feeders, we evaluated LTC-IC support in non-contact conditions above AFT024 feeders. We show that only 15% of LTC-IC were maintained for 5 weeks in AFT024 non-contact cultures (n=6, P<0.05). As AFT024-conditioned media added to M2-10B4 non-contact cultures did not inhibit LTC-IC maintenance, AFT024 cells do not secrete factors that inhibit LTC-IC growth. We next characterized heparan sulfate glycosaminoglycans (HS-GAGs) and cytokines produced by AFT024 cells, which are both required for LTC-IC maintenance in M2-10B4 non-contact cultures. The size and extent of O-sulfation of HS-GAGs in AFT024 and M2-10B4 conditioned medium were similar, indicating that absence of hematopoietic specific HS-GAGs is not responsible for the lack of hematopoietic in AFT024 non-contact cultures. Levels of 13 different cytokines secreted in AFT024- and M2-10B4-conditioned medium were similar. However, addition of human SCF, G-CSF, GM-CSF, LIF, MIP-1alpha and IL-6 in concentrations found in human marrow stroma-conditioned medium to AFT024 non-contact cultures increased LTC-IC-maintenance to 72% at 5 weeks. These cytokines improved LTC-IC maintenance in part through interaction with the progenitors and in part, through interaction with the AFT024 feeder. Thus, although LTC-IC maintenance is poor in AFT024 non-contact cultures, addition of human cytokines enhances LTC-IC maintenance in part through indirect effects on the AFT024 feeder. Characterization of known or novel growth factors secreted by AFT024 cells before and after cytokine stimulation may lead to the identification of cytokines that support growth of human hematopoietic stem cells.
Leukemia 1999 Jul
PMID:Factor(s) secreted by AFT024 fetal liver cells following stimulation with human cytokines are important for human LTC-IC growth. 1040 Apr 24

A novel biphenotypic leukemia cell line, NALM-29, was established from a 46-year-old Japanese male patient with acute lymphoblastic leukemia (ALL). The primary leukemic blasts showed a common ALL phenotype with CD19+, CD10+, CD13-, HLA-DR+ and Igs-. NALM-29 cells display biphenotypic characteristics: expression of the intracellular enzyme myeloperoxidase at the mRNA and protein level and cell surface positivity for CD19, CD10, CD13, CD33 and HLA-DR. NALM-29 fulfills EGIL criteria as B-cell precursor (BCP) leukemia B-II type. NALM-29 cells have a lymphoblastic morphological appearance; the immunoglobulin heavy chain gene is rearranged. NALM-29 cells responded significantly to the proliferative stimuli of FLT-3 ligand and IL-7, but not to GM-CSF, IL-3, IL-6, PIXY-321 or SCF. Proliferation of cells was inhibited significantly by IL-4, TNF-alpha or TNF-beta treatment. Cytogenetic analysis revealed the characteristic t(9;22)(q34;q11); expression of the m-bcr e1-a2 BCR-ABL fusion gene (typically found in ALL) was determined by PCR amplification of cDNA. The immunological, cytogenetic and functional characterization of NALM-29 suggests that this cell line may represent a scientifically significant in vitro model for BCP-type leukemia cells with biphenotypic characteristics.
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PMID:A novel biphenotypic B-cell precursor leukemia cell line (NALM-29) carrying t(9;22)(q34;q11) established from a patient with acute leukemia. 1045 71

We investigated the effect of a new fusion protein of IL-6 and the soluble IL-6R, H-IL-6, on the long-term ex vivo expansion of hematopoietic progenitors derived from AC133+cord blood cells. H-IL-6, which acts on both IL-6Ralpha-positive and IL-6Ralpha-negative cells, effectively synergized with FL and TPO with or without SCF for the propagation of primitive progenitors. However, IL-6 showed a greater synergistic effect with FL and TPO than H-IL-6 for long-term progenitor propagation. During the first 6 weeks of culture under stroma-free serum-containing conditions, IL-6 induced a 1.96 +/- 0.64-fold higher expansion of nucleated cells, a 2.28 +/- 0.33-fold higher expansion of CD34+ cells and a 2.74 +/- 0. 28-fold higher expansion of CD34+ AC133+ cells than H-IL-6 in combination with FL and TPO. The propagation of week 6 CAFC was up to four-fold higher in the presence of IL-6 than with H-IL-6. While the expansion of CD34+ and CD34+ AC133+ cells dropped after 5-7 weeks in the stroma-free cultures with FL, TPO and H-IL-6, a sustained expansion for 12 weeks was obtained in the presence of FL, TPO and IL-6. Stroma-contact greatly enhanced the progenitor expansion induced by FL and TPO or FL, TPO and H-IL-6 although the highest proliferation was again obtained in the presence of IL-6. In contrast, the presence of SCF resulted in increased differentiation. Since the majority of primitive progenitors are proposed to be IL-6Ralpha-negative, the results suggest that the synergistic effect of IL-6 is mediated by accessory cells, which have been more effectively stimulated by IL-6 than by the fusion peptide, H-IL-6, in this culture system.
Leukemia 1999 Dec
PMID:Gp130-signaling synergizes with FL and TPO for the long-term expansion of cord blood progenitors. 1060 26

Acute myeloid leukemia (AML) cells are malignant counterparts of normal myeloid pathway progenitors. Myeloid progenitors differentiate into professional antigen presenting cells (APC) under the essential influence of GM-CSF along with additional cytokines. Twelve cases of human AML were tested for ability to be differentiated toward a professional APC phenotype in short-term culture with addition of GM-CSF and the following recombinant proteins: TNFalpha, IL-4, CD40 ligand, Flt3 ligand and SCF. Significant upregulation of CD80 (B7-1) and enhancement of alloantigen presentation was seen with the addition of GM-CSF and TNFalpha alone or with additional cytokines. The combination of GM-CSF and TNFalpha, either alone or in combination with an additional cytokine, resulted in enhancing alloantigen presentation by at least two-fold over the media control group in 10/12 patients studied, and resulted in CD80 expression of greater than 15% in 11/12 patients studied. In AML cultures with GM-CSF and TNFalpha, coexpression of CD80 and either CD34 or an aberrant surface marker (CD56) was seen. In one case, sorted CD80, cells retained a characteristic cytogenetic marker and CD34 expression, proving their derivation from an AML precursor. These studies verify other reports of in vitro differentiation of human AML precursors into enhanced APC, suggesting that this phenomenon could be utilized for immunotherapy strategies aimed at enhancing presentation of leukemia antigens to T cells.
Leukemia 2000 Mar
PMID:Cytokine upregulation of the antigen presenting function of acute myeloid leukemia cells. 1072 Jan 35

The proliferative response of B cell precursor acute lymphoblastic leukemia (BCP-ALL) cells to IL-3 is dependent on the expression of functional IL-3 receptors (IL-3R). Here we report that CD40 ligand (CD40L) in the presence of recombinant IL-3 increased proliferation of BCP-ALL cells by upregulating expression of IL-3R. Upregulation of IL-3R in BCP-ALL cells was observed as early as 1 h after treatment with CD40L, and a 50- to 500-fold increase of IL-3R expression after 24 h was detected in all 12 cases studied. Moreover, expression of receptors for IL-7 (IL-7R) and stem cell factor (SCF-R, c-Kit) was also induced by CD40L in the majority of BCP-ALL cases examined; however, levels of induction were low compared to those for IL-3R. To test the functional activity of upregulated receptors for IL-3, SCF and IL-7, we evaluated the proliferation and growth of BCP-ALL cells cultured in serum-free media with CD40L plus these factors. When CD40L was added with either a single cytokine (IL-3, SCF and IL-7) or their combinations, cell proliferation was significantly increased as detected by DNA synthesis assay. Combinations of CD40L plus IL-3 and either SCF or IL-7 were able to support long-term growth of BCP-ALL cells for at least 8 weeks in three of the seven cases studied. Immunophenotyping and gene rearrangement studies indicated that cells in long-term cultures were monoclonal and retained their original phenotypes. The leukemic cells remained primarily dependent on the presence of IL-3 and its receptor for long-term growth, as shown by selective withdrawal of growth factors or antibody blockade of receptors. These results suggest an important role for CD40L in upregulating expression of IL-3R on BCP-ALL cells and enabling these cells to proliferate in long-term cultures in the presence of IL-3 and either SCF or IL-7.
Leukemia 2000 Mar
PMID:CD40 ligand upregulates expression of the IL-3 receptor and stimulates proliferation of B-lineage acute lymphoblastic leukemia cells in the presence of IL-3. 1072 Jan 34

Colony stimulating factors reduce the duration of neutropenia following intensive chemotherapy in a variety of settings, but the advantages in the management of leukemia are inconclusive. The variations in clinical results and the high costs of granulocyte colony-stimulating factor (G-CSF) and granulocyte macrophage colony-stimulating factor (GM-CSF) have led to confusion over appropriate use for leukemia patients. In this paper, we reviewed published information on costs and cost-effectiveness of growth factors for childhood and adult leukemia patients. Medline and Healthstar databases were searched for original research articles that contain cost or cost-effectiveness analyses of G-CSF (filgrastim) and GM-SCF (sargramostim) in oncology cooperative group trials. Published manuscripts and abstracts presented at national or international oncology conferences were included. The cost of adjunct treatment was evaluated in two studies of pediatric ALL, one study of adult AML, and two studies of AML in older adults (>55 years). The use of G-CSF for children with ALL was associated with reductions in days to ANC recovery, fewer documented infections, a shorter duration of hospitalization, and small (but not significant) additional costs. In adult AML patients, benefits included a shortening of the duration of neutropenia and hospital stays, a lower incidence of infection and febrile episodes, less use of antibiotics, and cost savings of $2,230 and $2,310 in two studies and an increase if $120 in the third study. This summary suggests that economic analyses can provide useful information to assist clinical decision-making. For pediatric ALL patients, this information indicates that G-CSF use is unlikely to have significant cost implications, and its use should be based on clinical considerations. In studies of adult and older adult AML patients, both GM-CSF and G-CSF have clinical benefits and can be expected to lead to a decrease in overall costs.
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PMID:Cost analyses of adjunct colony stimulating factors for acute leukemia: can they improve clinical decision making. 1072 70

Multidrug resistance protein (MRP1) is a member of the ATP-binding cassette (ABC) transmembrane transporter superfamily that confers multidrug resistance. The transfer and expression of the MRP1 gene in human hematopoietic stem cells may be a useful alternative to multidrug resistance (MDR1) gene transfer for protection from the myelosuppressive effects of chemotherapy in cancer patients. We constructed a gibbon ape leukemia virus packaging cell line (PG13) using the human MRP1 cDNA in a Moloney murine leukemia virus (MoMuLV) backbone containing a modified LTR. This PG13-based cell line, designated MRP1-PG13, produces retroviral vectors bearing the MRP1 gene at a titer of 1.7x10(5) viral particles/ml. Transduction of the human leukemic cell line K562 showed that viral MRP1-PG13 supernatants routinely transfer the MRP1 gene to approximately 35% of target K562 cells, of which at least one third are capable of proliferating in the presence of otherwise toxic concentrations of etoposide. Southern blot analyses indicated that most clones had only one proviral integration. Northern blot analysis of expanded K562 clones showed the presence of a major full-length approximately 8-kb MRP1 transcript as well as a minor approximately 6-kb transcript in all clones. Flow cytometric analysis of the producer cells and clones of transduced K562 cells demonstrated significantly increased MRP1 expression in these cells (approximately 30-fold increase). Human bone marrow mononuclear cells and CD34+ cells were also transduced with MRP1-PG13 supernatants on fibronectin-coated culture flasks in the presence of SCF, IL-3, and IL-6. PCR analysis of individual hematopoietic colonies in methylcellulose cultures demonstrated proviral DNA in approximately 10% of unselected human hematopoietic progenitor cells cultured from nonsorted mononuclear cell samples and in up to approximately 75% of progenitors when CD34-enriched cell populations were targeted. To assess functional MRP1 gene expression, normal human hematopoietic progenitors and K562 cells were cultured in methylcellulose assays containing vincristine or etoposide. All transduced samples gave rise to approximately 10% drug-resistant colonies, which were shown to be provirus-positive by PCR. Our studies document the development of an amphotropic MRP1 retroviral vector producer cell line and pave the way for large animal and preclinical studies of chemoprotection by MRP1 gene transfer.
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PMID:Retroviral-mediated transfer and expression of the multidrug resistance protein 1 gene (MRP1) protect human hematopoietic cells from antineoplastic drugs. 1079 1

The hematopoietic cell S/T kinase Pim-1 was originally discovered as a target of murine leukemia provirus integration, and when expressed at increased levels is predisposing to lymphomagenesis. Recently, Pim-1 has been shown to enhance the activities of p100, c-Myb and cdc25a, and in part this might explain reported effects on mitogenesis. In the context of cytokine withdrawal, Pim-1 also can attenuate programmed cell death (PCD). Cytokine withdrawal, however, alters signaling pathways and can complicate the dissection of mitogenic vs apoptotic responses. To better study possible effects of Pim-1 on PCD, a hematopoietic cell model was developed in which proliferation was supported efficiently by SCF plus EPO in the absence of endogenous Pim-1 gene expression. This was provided by factor-dependent FDCW2 cells that express endogenous and functional c-Kit, and were transfected stably with truncated Epo receptor form mutated at a Y343 STAT5 binding site. In proliferating cells, exogenously expressed Pim-1 was observed to efficiently inhibit PCD as induced by either Co60 or adriamycin, and the dose-dependent nature of this effect was established in several independent clones. By comparison, effects of exogenous Pim-1 on mitogenesis were nominal. In addition, in cell fractionation studies an estimated 25% of Mr 34000 Pim-1 (but not Mr 44000 Pim-1) was present in nuclear extracts. Thus, Pim-1 efficiently buffers hematopoietic progenitor cells against death as induced by several clinically important apoptotic agents, and may directly target nuclear effectors.
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PMID:Pim-1 kinase protects hematopoietic FDC cells from genotoxin-induced death. 1095 75

To develop a model of early human adult B lymphopoiesis, we cultured CD34+CD38+CD10+ pro-B cells in contact with AFT024 stroma in X-VIVO10 media with 5% serum. The cytokines FLT3L + SCF + IL7 + IGF1 were added at day 0, IL4 + IL5 + IL6 + IL10 and soluble CD40 ligand at day 14, and Staph. aureus Cowan particles on day 21. Greater than 25-fold expansion of CD34+CD38+CD10+ cells was seen at 2 weeks, the majority being CD34-CD19+ pre-B cells. Differentiation to immature IgM+ B cells was seen at 3 weeks and mature IgD+ B cells at 4 weeks, with secretion of IgM into the media. Immature and mature B cells could also be generated from culture of CD34+CD10+CD19- and CD34+CD10+CD19+ cells under similar conditions. In conclusion, we have demonstrated in vitro differentiation of early pro-B cells, and possibly common lymphoid progenitor cells, to mature B cells. Additional stimuli, provided by T helper cells or dendritic cells for example, may be required for the generation of IgG+ B cells or plasma cells. However, our culture system should be a valuable tool to further investigate B cell biology and B cell malignancies such as multiple myeloma and lymphoma.
Leukemia 2000 Sep
PMID:A novel in vitro model of early human adult B lymphopoiesis that allows proliferation of pro-B cells and differentiation to mature B lymphocytes. 1099 8


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