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)

A limited number of biologically active materials were examined for their relative ability to selectively inhibit the replication of Gross or Rauscher murine leukemia virus (MLV) in Swiss mouse embryo cells by means of the UV-XC plaque-reduction assay. Among the compounds demonstrating significant antiviral activity against Gross MLV in vitro were 1-(4-fluorobenzyloxy) adenosine (FBAR), polyadenylic acid [poly(A)], the carbocyclic analogue of 6-methylthiopurine ribonucleoside (C-MeMPR), 3-(2,4-dinitrophenylhydrazonemethyl)rifamycin SV (AF/DNFI), and phosphonoacetic acid (PAA). Five compounds that exhibited significant antiviral activity against MLV in vitro were tested for similar activity against Rauscher MLV in vivo. Three of these selected compounds, pyrazofurin (pyrazomycin), ribavirin (Virazole), and 9-beta-D-arabinofuranosyladenine (ara-A), produced a significant (50%-100%) inhibition of virus-induced splenomegaly development in mice, whereas the other two candidate inhibitors, 3-deazauridine (deazaUR) and rifamycin SV, the other two candidate inhibitors, 3-deazauridine (deazaUR) and rifamycin SV, failed to demonstrate any in vivo activity in this 21-day leukemogenesis assay. The administration of an inhibitor of adenosine deaminase (Co-vidarabine) in combination with ara-A resulted in an enhanced antiviral response in both infected cell cultures and animals. Co-vidarabine also increased the potency of ara-AMP against Gross MLV in vitro, indicating the probable dephosphorylation of the compound to ara-A and its subsequent deamination to ara-H in this system.
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PMID:Selective inhibition of RNA tumor virus replication in vitro and evaluation of candidate antiviral agents in vivo. 28 Jan 46

A competitive radioimmunoassay for a saline-soluble human thymus-leukemia-associated antigen (HThy-L) was applied for quantitation of this antigen in leukemia and normal hematopoietic cell lines. Highly increased quantities of HThy-L were detected in all T-cell leukemia lines tested, regardless of the presence or absence of receptors for sheep erythrocytes. This elevated level of HThy-L in combination with high terminal deoxynucleotidyl transferase and adenosine deaminase activities and the presence of a T-lymphocyte-specific surface antigen appear to represent stable phenotypic characteristics of T-cell lines. Most normal B-cell lines had low quantities of HTy-L. The level of HThy-L was slightly elevated in a considerable number of lymphoma B-cell lines and in all non-T, non-B leukemia cell lines tested. No relationship existed between quantities of HThy-L and an expression of different surface immunoglobulin isotypes in B-cell lines. Low quantities of HThy-L were detected in leukemia myeloid and myeloma cell lines as well as in B-cell leukemia lines originating from patients with B-cells acute lymphoblastic leukemia. Apparently, the increased quantities of HThy-L in T-cell leukemia lines may be related to certain stages of T-cell differentiation at which leukemia cell transformation occurs.
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PMID:Quantitation of human thymus-leukemia-associated antigen in established hematopoietic cell lines by radioimmunoassay. 31 16

A causal relation between the enzyme, adenosine deaminase (ADA), and immune dysfunction is well known: patients with congenital inactivity of ADA invariably suffer of severe combined immunodeficiency. In contrast, we found in patients treated with immunosuppressive drugs increased ADA enzyme activity. Previous findings on ADA activity in acute leukemias are until now controversial. We found normal to increased ADA activity in children with acute lymphatic leukemia (ALL) and acute myeloid leukemia (AML) in remission as long as they were treated with cytostatic drugs. In the group of cured leukemics (in continuous remission after suspension of the therapeutic regimen) the ADA activities were normal. These findings do not exclude a heterogeneity within the leukemia group. They do not explain the signs of cellular immunodeficiencies well known in patients with acute leukemias.
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PMID:[Adenosine deaminase activity in blood cells; influence of cytostatic therapy in patients with acute leukemia and with renal transplants (author's transl)]. 39 66

The antibiotic 2'-deoxycoformycin, a potent inhibitor of adenosine deaminase, has potential as a chemotherapeutic agent. Injection of 2'-deoxycoformycin i.v. (0.2 mg/kg) to mice bearing ascites L1210 leukemia cells completely inhibits adenosine deaminase in both erythrocytes and L1210 cells. The recovery of the enzymic activity is markedly different in the two tissues. The recovery is very slow in erythrocytes (13% in 48 hr), whereas 80% recovery occurs during the same time interval in L1210 cells. This marked difference in the recovery of the enzyme in different tissues may play a role in the pharmacological and chemotherapeutic behavior of this drug.
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PMID:Recovery of 2'-deoxycoformycin-inhibited adenosine deaminase of mouse erythrocytes and leukemia L1210 in vivo. 42 Dec 26

The metabolism of 9-beta-D-arabinofuranosyladenine (AraA) to arabinofuranosyladenine 5'-triphosphate (AraATP), an inhibitor of DNA synthesis, in mouse leukemia cells was examined by means of high-pressure liquid chromatography. AraATP was separated from naturally occurring nucleotides in acid-soluble extracts and quantitative measurements of AraATP levels were made. A potent inhibitor of adenosine deaminase (2'-deoxycoformycin; co-vidarabine), when used in combination with AraA in the treatment of leukemia-bearing mice, increased the formation of AraATP in mouse leukemia cells four- to five-fold over that obtained by treatment with AraA alone. By means of high-pressure liquid chromatography the half-life of AraATP in tumor cells could be measured. Results of such studies may be of value in planning chemotherapy regimens.
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PMID:Analysis by high-pressure liquid chromatography of 9-beta-D-arabinofuranosyladenine 5'-triphosphate levels in murine leukemia cells. 55 57

The rational design of antitumor and antiviral agents must ultimately take advantage of biochemical differences between normal host cells and transformed cells. The initial experiments must be performed with subcellular or cellular model systems. For the studies with arabinosyl nucleosides we have chosen those enzyme systems, synthesizing DNA and RNA; being precursor analogues, the different arabinosyl nucleosides have been added in the triphosphate state to the different DNA- and RNA polymerase assays. 1-beta-D-Arabinofuranosylcytosine-5'-triphosphate has been found to inhibit the RNA-dependent DNA polymerases (isolated from oncogenic RNA viruses) 200-fold more sensitively than viral and cellular DNA-dependent DNA polymerases. Recent results, showing that RNA-leukemia-virus-related sequences are present in DNA of some human leukemia patients might support the assumption that the efficacy of this antimetabolite in the treatment of acute leukemia is due to its, at least relative selective inhibitory activity on reverse transcriptase. 9-beta-D-Arabinofuranosyladenine-5'-triphosphate is a strong inhibitor of cellular DNA polymerases with the cytological consequence of an inhibition of cell proliferation. The clinical benefit of the compound in treatment of tumors is dependent on their levels of adenosine deaminase. The triphosphate of this compound is a 100-fold more sensitive inhibitor of the herpesvirus DNA polymerase compared to the cellular replicative DNA polymerase. In addition the analogue, incorporated into herpesvirus DNA, acts as chain terminator. These effects are the biochemical basis for the highly selective antiherpesvirus activity of this antimetabolite. The anomer 9-alpha-D-arabinofuranosyladenine-5'-triphosphate only inhibits cellular replicative DNA polymerase and has no effect on herpesvirus DNA polymerase. Consequently this agent acts only cytostatically and not antivirally. Concerning 1-beta-D-arabinofuranosyluracil and 1-beta-D-arabinofuranosylthymine no pronounced antitumor or antiviral effect is known.
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PMID:Rational design of arabinosyl nucleosides as antitumor and antiviral agents. 61 2

The potent adenosine deaminase inhibitor 2'-deoxycoformycin ((R)-3-(2-deoxy-beta-D-erythropentofuranosyl)-3,6,7,8-tetrahydroimidazo[4,5-d][1,3]diazepin-8-ol) inhibits the enzymic inactivation and potentiates the cytotoxic activity of a variety of adenosine analogs in the P388 murine leukemia cell culture system. The activity of all seven adenosine analogs examined was enhanced by 2'-deoxycoformycin with the exception of tubercidin (7-deaza-adenosine) which is not a substrate for the deaminase. In vivo, 2'-deoxy-coformycin potentiated the antineoplastic activity of 9-beta-D-xylofuranosyladenine in mice with P388 murine leukemia.
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PMID:Enhancement of the biological activity of adenosine analogs by the adenosine deaminase inhibitor 2'-deoxycoformycin. 84 Aug 92

1. The presence of adenosine receptors linked to adenylate cyclase activity and their functional role in calcium-evoked 5-hydroxytryptamine (5-HT) release was investigated in rat basophilic leukaemia (RBL) cells, a widely used model for studying the molecular mechanisms responsible for stimulus-secretion coupling. 2. In [3H]-5-HT-loaded cells triggered to release by the calcium ionophore A23187, a biphasic modulation of 5-HT secretion was induced by adenosine analogues, with inhibition of stimulated release at nM and potentiation at microM concentrations, suggesting the presence of adenosine receptor subtypes mediating opposite effects on calcium-dependent release. This was also confirmed by results obtained with other agents interfering with adenosine pharmacology, such as adenosine deaminase and the non-selective A1/A2 antagonist 8-phenyl-theophylline. 3. Similar biphasic dose-response curves were obtained with a variety of adenosine analogues on basal adenylate cyclase activity in RBL cells, with inhibition and stimulation of adenosine 3':5'-cyclic monophosphate (cyclic AMP) production at nM and microM concentrations, respectively. The rank order of potency of adenosine analogues for inhibition and stimulation of adenylate cyclase activity and the involvement of G-proteins in modulation of cyclic AMP levels suggested the presence of cyclase-linked A1 high-affinity and A2-like low-affinity adenosine receptor subtypes. However, the atypical antagonism profile displayed by adenosine receptor xanthine antagonists on cyclase stimulation suggested that the A2-like receptor expressed by RBL cells might represent a novel cyclase-coupled A2 receptor subtype.4. Micromolar concentrations of adenosine analogues could also increase inositol phospholipid hydrolysis and inositol tris-phosphate formation in both unstimulated cells and in cells triggered to release by the calcium ionophore. The stimulation was constant, small and additive to that exerted by the calcium ionophore.5. It is concluded that RBL cells express both A1 and A2-like adenosine receptors which exert opposite effects on 5-HT release and intracellular cyclic AMP levels. However, besides modulation of cyclic AMP levels, additional transduction pathways, such as modulation of phospholipase C activity, may contribute to the release response evoked by adenosine analogues in this cell-line.
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PMID:Adenosine receptors in rat basophilic leukaemia cells: transductional mechanisms and effects on 5-hydroxytryptamine release. 131 28

YK-176 is a newly isolated 2'-deoxycoformycin (DCF), a potent inhibitor of adenosine deaminase, produced by Aspergillus nidulans. In a cooperative phase I study, YK-176 was administered to 22 patients, comprising 18 with adult T-cell leukemia-lymphoma (ATL), two with cutaneous T-cell lymphoma (CTCL), one with lymphoblastic lymphoma of T-cell type and one with carcinoma of the uterine cervix. Doses of YK-176 ranged from 3.0 to 9.0 mg/m2 and were given intravenously for three consecutive days. General malaise, anorexia, nausea, vomiting and low grade fever were frequently encountered, but were transient and not dose-related. At all dose levels hematological toxicities were mild. Two of seven patients receiving 7.0 mg/m2 for three consecutive days developed hepatocellular enzyme elevations (grade 2) and one patient, proteinuria (grade 2). One of two patients given 9.0 mg/m2 for three consecutive days manifested a life-threatening (grade 4) disturbance of consciousness and dyspnea, presumably ascribable to the drug-related toxicity of YK-176. The results suggest that 7.0 mg/m2 i.v. for three consecutive days is the maximum acceptable dose of YK-176. Central nervous system, pulmonary and possibly renal toxicities appeared to be dose-limiting. Out of the 20 patients evaluable for therapeutic response, partial remissions were observed in four, three with ATL and one with CTCL, who received less than 7.0 mg/m2 for three consecutive days. We conclude that YK-176 is an active agent against ATL at doses that may not be associated with prohibitive toxicity. A starting dose of 5.0 mg/m2 for three consecutive days is recommended for further phase II studies on ATL.
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PMID:Phase I study of YK-176 (2'-deoxycoformycin) in patients with adult T-cell leukemia-lymphoma. The DCF Study Group. 151 64

To determine the effect of different promoters on the expression of an altered dihydrofolate reductase (DHFR) gene conferring methotrexate (MTX) resistance in different cell types, double-copy retroviral vectors were constructed carrying a murine mutant DHFR under the control of five different promoters, i.e., human adenosine deaminase (ADA), simian virus 40 (SV40), thymidine kinase (TK), human beta-actin, and cytomegalovirus (CMV). Their expression was compared in NIH-3T3 cells, three human leukemia cell lines, and mouse bone marrow. The variant DHFR is readily expressed from these various promoters in retroviral vectors at a selectable level. In 3T3 cells, the DHFR constructs containing the SV40 promoter conferred the highest levels of resistance to MTX. In K562 and Raji cells, the construct with the TK promoter produced the highest level of resistance. However granulocyte-macrophage colony-forming unit (CFU-GM) colonies from mouse marrow were more resistant to MTX when infected with vectors containing the SV40 promoter and ADA promoter as compared to the other promoter constructs. These studies show that mouse fibroblast cell lines such as NIH-3T3 do not predict the effectiveness of retroviral-mediated gene transfer for marrow progenitor cells, and that the activity of retroviral vector-encoded promoters vary in an unpredictable manner from cell type to cell type. Possible implications for basic gene transfer studies and clinical applications are discussed.
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PMID:Comparison of the expression of a mutant dihydrofolate reductase under control of different internal promoters in retroviral vectors. 152 11


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