Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Expression of the myeloperoxidase (MPO) gene at the mRNA level is a better lineage marker than enzymatic activity in early myeloid precursors and their leukemic counterparts. Its diagnostic use depends on the specificity of expression for myeloblasts and its absence in blasts of lymphoid lineage. The present study investigates MPO mRNA expression in adult acute lymphoblastic leukemia (ALL), using reverse transcription-polymerase chain reaction. Of a total of 13 cases, six were found to have blasts positive for MPO mRNA; in all of these cases, the blasts were cytochemically negative for MPO. This unexpected finding of MPO mRNA positivity in six of 13 cases was further investigated at the molecular level. Bcr gene rearrangement analysis was positive in all six cases for the bcr breakpoint diagnostic of chronic myelogenous leukemia (CML). Only three of these six cases were cytogenetically positive for a Philadelphia (Ph) chromosome. Based on molecular analysis, these cases are considered as CML presenting in blast crisis of lymphoid lineage, as opposed to de novo ALL. The remaining seven cases were Ph negative at the cytogenetic and molecular levels; the leukemic blasts were MPO mRNA negative, confirming the lack of MPO gene expression in de novo ALL.
Diagn Mol Pathol 1996 Dec
PMID:Myeloperoxidase mRNA analysis in acute lymphoblastic leukemia. 927 91

Recent studies of the BCR-ABL fusion protein, the product of the oncogene responsible for chronic myelogenous leukemia, have identified a number of signal transduction pathways that are activated by this tyrosine kinase. In some cases, these pathways are critical mediators of the growth stimulatory effects of the oncogene on hemopoietic cells. This knowledge has been translated into therapeutic strategies that directly target BCR-ABL or the signaling pathways that BCR-ABL activates. Promising results in animal models have led to the design of Phase I clinical trials, which are in progress or will be under way shortly. These studies are among the first to target a specific genetic abnormality in human cancer.
Mol Med Today 1996 Dec
PMID:Signal transduction-based strategies for the treatment of chronic myelogenous leukemia. 901 91

In Ph1+-CML the abnormal function of bone marrow stroma was related to the presence of clonally transformed macrophages (MAs). Moreover, previous in vitro studies revealed that activation (phagocytosis, cytotoxicity) of MAs was associated with a pronounced increase in alpha-D-galactosyl residues on their membranes. Stimulation of this cell population has been shown to be easily accomplished by interferon (IFN) treatment. The latter caused an enhanced expression of binding sites for the lectin Griffonia simplicifolia isotype I-B4 (GSA-I), specific for this carbohydrate moiety. The present immuno- and lectinhistochemical study was designed to quantify MA subsets of the bone marrow in patients with Ph1+-CML under IFN therapy. For comparison a control group with monotherapy by busulfan (BU) was included. Identification of the total MA population was carried out by a monoclonal antibody against CD68 (PG-M1) and for the characterization of its activated fraction, the lectin GSA-I was employed. In both therapeutic groups morphometric analysis revealed a conspicuous increase in PG-M1-positive MAs in sequential trephine biopsies. However, following IFN therapy the relative amount of the GSA-I fraction was maintained or even increased and accompanied by enhanced apoptosis. On the other hand, BU generated a significant reduction of this subpopulation and the number of apoptotic cells as well. This finding is probably related to the immunomodulatory activity of IFN associated with MA activation and secretion of biogenic mediators. These are thought to belong partly to the so-called tumor necrosis factor superfamily, which is known to stimulate programmed cell death (apoptosis).
Hematopathol Mol Hematol 1996
PMID:Effects of interferon treatment on the macrophage population in the bone marrow of patients with Ph1+-CML. 904 63

We conducted a retrospective study to assess the changes in bone marrow (BM) stromal antigenic profile and fibrosis in chronic myeloid leukemia (CML) under combined interferon-alpha (IFN) and Ara-c therapy. Bone marrow biopsies were taken before therapy and twice (at 4 and 15 months) during therapy in 10 CML patients and compared with non-CML samples. Collagen and reticulin fibrosis was assessed by histochemical methods and phenotypic changes were studied by immunohistochemistry (APAAP) with antibodies directed against endothelial cell antigens, cell adhesion molecules, and HLA-DR. It was found that: (1) BM endothelial cells in patient and in control specimens showed a specific pattern of antigen expression: high expression of FVIII and CD34 (except on sinusoids for the latter), variable expression of UEA I, and no expression of HLA-DR and E-selectin. (2) Compared to non-CML controls, CML specimens at diagnosis showed an increased reticulin fibrosis and a decreased expression of CD61 on megakaryocytes and of CD31 on vessels and hemopoietic cells. (3) Treatment did not influence BM fibrosis, the vascular content of the BM, or the expression of the antigens tested except an increase in the number of CD34+ sinusoids (5/10 patients), an increase in the number of HLA-DR+, and a decrease in the number of CD34+ hemopoietic cells (6/10). (4) On therapy, difficulty in aspiration and/or reduced BM fragment numbers were noted in 8 of 10 patients whose bone marrow was still normocellular or slightly hypercellular. In conclusion, CML samples at diagnosis showed increased fibrosis and decreased CD31 and CD61 expression compared to controls. During the period of observation, combined therapy did not modify BM fibrosis; however, an increase in CD34+ sinusoids and a decrease in CD34+ hemopoietic cells were noted.
Hematopathol Mol Hematol 1996
PMID:Evolution of bone marrow fibrosis and stromal antigenic expression in chronic myeloid leukemia on alpha interferon and Ara-C therapy. 904 64

Band 3, a major erythrocyte membrane glycoprotein, undergoes topographic redistribution leading to enhanced clustering, in chronic myelogenous leukemia (CML). This is probably due to the binding of heme compounds to the CML erythrocyte membrane resulting from depletion of cellular levels of reduced glutathione (GSH). Band 3 clustering appears to be one of the factors associated with increased erythrophagocytosis in CML.
Biochem Mol Biol Int 1997 Mar
PMID:Erythrophagocytosis and its relation to band 3 clustering in chronic myelogenous leukemia. 909 Apr 61

BCR-ABL is a chimaeric oncogene generated by translocation of sequences from the c-ABL protein-tyrosine kinase gene on chromosome 9 into the BCR gene on chromosome 22. Alternative chimeric proteins, p210(BCR-ABL) and p190(BCR-ABL), are produced that are characteristic of chronic myelogenous leukemia and acute lymphoblastic leukemia, respectively. Their role in the aetiology of human leukemia remains to be defined. We have previously shown that the tumorigenic effect of BCR-ABL oncogenes is mediated by Bcl-2. In addition to Bcl-2, is a protein essential for transformation by BCR-ABL. However, it is not known how Bcl-2 and Ras fit together in cell transformation by BCR-ABL. The data presented here establish that Bcl-2 is a downstream target gene of the Ras signalling pathway in cells transformed by BCR-ABL, and that constitutive Ras activation results in constitutive expression of the gene. Conversely, a truncated form of the BCR-ABL, which lacks a critical BCR region required for activation of the Ras signalling pathway, failed to induce Bcl-2 expression. These results indicate that BCR-ABL prevents apoptosis by inducing Bcl-2 through a signalling pathway involving Ras and links constitutive Ras activation and Bcl-2 gene regulation. Hence, these results further imply that Ras is involved in both mitogenic signals and survival signals.
J Mol Biol 1997 Mar 28
PMID:Regulation of Bcl-2 gene expression by BCR-ABL is mediated by Ras. 909 20

We investigated the role of endogenous or exogenous nitric oxide (NO) on human lymphocyte function. We used sodium nitroprusside, nitroglycerine, S-nitroso-N-acetylpenicillamine, sodium nitrite and S-nitroso-L-glutathione as NO-generating compounds. All agents were used at doses that do not produce direct cytotoxicity as measured by trypan blue exclusion as well as chromium-51 release assay. The immune responses examined were peripheral blood lymphocytes (PBL) proliferation and IL-2 production after activation with OKT3 and PHA; allogeneic mediated proliferation and cell mediated cytotoxicity (CML) in MLR; IgG and IgM production after PBL activation with Con-A; proliferation and expression of IFN-gamma and IL-4 mRNA after activation of allogeneic CD4+T cell clones. Cytokine mRNA expression was measured by reverse transcriptase PCR. Our results show that proliferating lymphocytes do not produce a detectable amount of NO as measured by the Griess reaction. In separate experiments, the addition of NG-monomethyl-L-arginine (L-NMMA) did not affect lymphocyte proliferation. Sodium nitroprusside and nitroglycerine exerted a dose dependent antimitogenic effect, inhibited cytokine production and expression, CML generation and antibody production. DNA gel electrophoresis showed no evidence for enhanced programmed cell death. The antimitogenic effect could not be blocked by the NO scavengers, hemoglobin or methylene blue. In contrast, the other nitric oxide generating compounds did not inhibit lymphocyte mitogenesis. The results suggest that human lymphocytes do not produce appreciable amounts of NO to affect lymphocyte mitogenesis. Sodium nitroprusside and nitroglycerine have a potent but nonspecific immunoinhibitory effect on human lymphocyte function by a mechanism other than NO production. In addition, pharmacological levels of NO do not inhibit human lymphocyte mitogenesis.
Mol Cell Biochem 1997 Jun
PMID:Analysis of the in vitro effect of exogenous nitric oxide on human lymphocytes. 920 99

Publication in this journal of the abstracts of the Nineteenth Symposium of the International Association for Comparative Research on Leukemia and Related Diseases in Mannheim/Heidelberg led editor and publisher to suggest an article introducing comparative research in leukemia and related diseases. Our survey briefly summarizes the history of this symposium, as it evolved from a meeting on animal leukemia virus into one dealing with viral and genetic aspects of human and animal leukemia and related diseases. The scientific evolution of the Abelson murine leukemia virus with its abl oncogene in the 1970s to what currently appears as the most reliable marker for human chronic myeloid leukemia is merely one example.
J Mol Med (Berl) 1997 Jul
PMID:Comparative research on leukemia and related diseases: an introduction to a scientific approach. 925 16

We demonstrated previously that the nucleoside of fludarabine (F-ara-A), a clinically effective agent against chronic lymphocytic leukemia and low-grade lymphoma, produces synergistic cytotoxicity against cisplatin-resistant CP2.0 human colon tumor cells when administered in combination with cisplatin. The purpose of this study was 2-fold: (i) to determine whether the synergy occurs in K562 human chronic myelogenous leukemia cells, which, unlike CP2.0 cells, are relatively resistant to drug-induced apoptosis because they express P210(bcr-abl) and (ii) to study the underlying mechanism for the synergy if the enhancement of cytotoxicity occurs in K562 cells. When K562 cells were treated with fludarabine nucleoside and cisplatin as single agents for 4 hr, IC50 values for fludarabine and cisplatin were 3.33 and 2.28 microM, respectively, as measured by a clonogenic survival assay. The simultaneous treatment of K562 cells with the two agents resulted in synergistic cell killing as determined by median-effect analysis. Such synergistic cell killing by combined cisplatin and fludarabine could not be detected in repair-deficient human xeroderma pigmentosum cell lines. Within the range of cytotoxic concentrations, fludarabine (2.5-15 microM) and cisplatin (3-30 microM) as single agents produced no detectable internucleosomal DNA fragmentation as revealed by gel electrophoresis, nor did the combination of the two drugs induce apoptotic DNA degradation. The effects of fludarabine on the repair of cisplatin-induced DNA adducts and interstrand cross-links in K562 cells were analyzed to determine their correlation with the cytotoxic synergy. The interstrand cross-links were measured by the ethidium bromide binding fluorescence assay and quantitative Southern blotting technique. Repair of the intrastrand adducts was detected with whole-cell extracts using a cisplatin-damaged plasmid as the substrate for the in vitro repair assay. Fludarabine at clinically achievable concentrations (1.5-4.5 microM fludarabine nucleoside; 20-100 microM fludarabine triphosphate) inhibited the repair of the DNA lesions induced by cisplatin in a dose-dependent fashion in K562 cells but not in xeroderma pigmentosum cells. Cotreatment with fludarabine preferentially increased the number of interstrand cross-links induced by cisplatin in actively transcribed genes in K562 cells. These data demonstrate the DNA-repair-inhibitory effect of fludarabine and suggest that this effect may contribute to the synergistic cytotoxicity of the fludarabine/cisplatin combination that resulted in decreased clonogenic survival of apoptosis-resistant K562 cells.
Mol Pharmacol 1997 Nov
PMID:Fludarabine-mediated repair inhibition of cisplatin-induced DNA lesions in human chronic myelogenous leukemia-blast crisis K562 cells: induction of synergistic cytotoxicity independent of reversal of apoptosis resistance. 935 70

We treated 12 patients with leukemia relapse after allogenic bone marrow transplantation with a combination of interferon-alpha (IFN-alpha) ((2.5-5.0) x 10(6) u/m2 subcutaneously three times a week) and interleukin-2 (IL-2) ((1.8-3.6) x 10(6) IU/m2 subcutaneously five times a week) to determine the toxicity and efficacy of combination cytokine therapy in this setting. The median age of the patients was 39 years (range: 16-50). There were nine females and three males. The median time to relapse from BMT was 98 days (range: 0-963). At the time of relapse, six patients had AML, four patients had CML (two in blast crisis and two in chronic phase with clonal evolution), and one patient had lymphoblastic lymphoma. Combination cytokine therapy was started a median of 108 days post BMT (range: 37-2404). Nine patients treated at the higher dose level required a 50% dose reduction because of toxicity or GVHD (three CNS, two GVHD, one high fever, one diarrhoea with hypotension, and one pericarditis). At a lower dose level, 2 of 10 patients had their treatment discontinued because of toxicity or GVHD. Six patients developed clinical findings consistent with acute GVHD while on combination cytokine therapy. Two patients responded to combination cytokine therapy: one with CML and one with AML. Combination cytokine therapy is feasible in the setting of relapse post allogeneic BMT. The combination of IL-2 1.8 x 10(6) IU/m2 five times a week with IFN-2 2.5 x 10(6) U/m2 three times a week seems to be tolerable, and merits further study in this setting.
Cytokines Mol Ther 1995 Jun
PMID:Interferon-alpha and interleukin-2 as treatment for leukemia relapse after allogeneic bone marrow transplantation. 938 68


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