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)

The synthetic "C" nucleoside, tiazofurin (2-beta-D-ribofuranosylthiazole-4-carboxamide), its selenium analogue selenazofurin, and the related inhibitor of inosine 5'-phosphate (IMP) dehydrogenase, mycophenolic acid, are effective inducers of the terminal differentiation of HL-60 promyelocytic leukemia cells. The inhibition of cellular replication and the induced maturation produced by these agents appears to be a consequence of the inhibition of IMP dehydrogenase, since growth inhibition is partially reversed and differentiation is completely prevented by the simultaneous exposure of cells treated with inhibitors of IMP dehydrogenase to exogenous guanosine, which serves to circumvent the effects of the blockage of IMP dehydrogenase. The exposure of HL-60 leukemia cells to inhibitors of IMP dehydrogenase caused a marked reduction in the incorporation of [3H]mannose into both cellular glycoproteins and their lipid-linked oligosaccharide precursors; these effects are presumably due to the pronounced decrease in intracellular levels of guanosine triphosphate produced by blockage of IMP dehydrogenase. Maximum effects on glycoprotein biosynthesis occurred within 8 h of exposure to the inhibitors of IMP dehydrogenase. The simultaneous incubation of cells with guanosine and these inducers of differentiation partially prevented the reduction in [3H]mannose incorporation into glycoproteins, supporting a relationship between glycoprotein biosynthesis and guanosine triphosphate formation in the induction of differentiation by inhibitors of IMP dehydrogenase.
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PMID:Alterations in glycoprotein synthesis and guanosine triphosphate levels associated with the differentiation of HL-60 leukemia cells produced by inhibitors of inosine 5'-phosphate dehydrogenase. 287 Jul 96

Following a wet digestion of 0.5-2.0 ml cerebrospinal fluid in an open system using 2.0 ml nitric acid and 1.0 ml perchloric acid (240 degrees C) and a reduction step with 1.0 ml hydrochloric acid, Selenium can be determined polarographically after adding 100 micrograms Copper(II)-ions to the analyte (15 ml; water/perchloric acid). Selenium concentrations in cerebrospinal fluid of children younger than one year (2.49 +/- 1.67 ng/ml) are significantly higher (p = 0.0074) than those of older children (1.28 +/- 0.97 ng/ml). Independent of the childrens age and diseases the Selenium concentrations correlate distinctly with cell numbers and protein contents. A correlation between Selenium content and cell numbers alone could not be proved. The non-significant differences between the Selenium concentrations in cerebrospinal fluids of children with hydrocephalus, leukemia (with or without involvement of the central nervous system), and other diseases, respectively, may be interpreted by considering the protein content of the cerebrospinal fluid and the age of the children.
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PMID:[Selenium concentration in the cerebrospinal fluid of children]. 347 10

Following a wet digestion of 0.5-2.0 ml cerebrospinal fluid in an open system using 2.0 ml nitric acid and 1.0 ml perchloric acid (240 degrees C) and a reduction step with 1.0 ml hydrochloric acid, Selenium can be determined polarographically after adding 100 micrograms Copper(II)-ions to the analyte (15 ml; water/perchloric acid). Selenium concentrations in cerebrospinal fluid of children younger than one year (2.49 +/- 1.67 ng/ml) are significantly higher (p = 0.0074) than those of older children (1.28 +/- 0.97 ng/ml). Independent of the children age and diseases the Selenium concentrations correlate distinctly with cell numbers and protein contents. A correlation between Selenium content and cell numbers alone could not be proved. The nonsignificant differences between the Selenium concentrations in cerebrospinal fluids of children with hydrocephalus, leukemia (with or without involvement of the central nervous system), and other diseases, respectively, may be interpreted by considering the protein content of the cerebrospinal fluid and the age of the children.
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PMID:[Selenium concentration in the cerebrospinal fluid of children]. 361 44

Selenium exists in a number of forms with differing valence states, some of which have shown antitumor activity. We studied the tumoricidal activity of four currently available selenium forms against a human leukemia cell line and exploited the differences among them to investigate the mechanism of antitumor action. Only selenocystine and sodium selenite showed antitumor activity, and these were also the only compounds which demonstrated significant redox chemistry, including depletion of cellular glutathione, stimulation of glutathione reductase, and stimulation of oxygen consumption. The interaction of these two compounds with glutathione suggests an intriguing potential role for them in cancer therapy.
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PMID:Selenium-induced cytotoxicity of human leukemia cells: interaction with reduced glutathione. 375 96

Female hairless inbred hr/hr mice were exposed to UV-B irradiation from Philips TL 40W/12 fluorescent tubes. Fractionated irradiation, given as single daily doses 5 days a week, was gradually increased from 0.04 to 0.4 J/cm2 over 2 weeks. Irradiation at 0.4 J/cm2 was continued for 20 weeks. Selenium supplementation given as sodium selenite in the drinking water at 2, 4 and 8 mg/l began 3 weeks before UV-irradiation and continued thereafter. Development of skin tumors was followed by weekly examinations. Statistical analyses revealed significant dose-dependent selenium-mediated protection against UV-light-induced skin cancer. Leukemia developed in 5 of 150 UV-irradiated mice as opposed to none in a group of 60 unirradiated mice.
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PMID:Selenium inhibits UV-light-induced skin carcinogenesis in hairless mice. 400 28

A primary xenogeneic culture system has been devised that selectively generates undifferentiated TdT+ lymphoblasts from rat bone marrow under conditions that do not support the growth or maintenance of rat colony-forming unit-spleen (CFU-S) or granulocyte/macrophage colony-forming cells (GM-CFC). The culture system requires a mouse bone marrow feeder layer, and a serum supplement that has markedly reduced levels of cortisol. The growth of TdT+ cells can be significantly enhanced by the addition of mesodermalizing factors (e.g., fibroblast growth factor, guinea pig bone marrow extract) to the culture medium, and the serum supplement can be decreased by the addition of selenium, transferrin, and T3. The cultured TdT+ cells are antigenically "null" cells that further resemble their normal counterparts in bone marrow with respect to morphology, size, cortisone sensitivity, and pattern of TdT fluorescence. The TdT+ cells are generated with equal facility from bone marrow of normal and congenitally athymic rats, can be maintained in logarithmic growth for at least 10 mos by serial passage in vitro, and do not cause leukemia when infused into irradiated recipients. Although the lineage relationships of these immature lymphoid cells have not yet been established, our working hypothesis, based on preliminary evidence, is that the cultured TdT+ cells are primitive members of the T cell series.
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PMID:A selective culture system for generating terminal deoxynucleotidyl transferase-positive (TdT+) lymphoid precursor cells in vitro. I. Description of the culture system. 621 Mar 37

Rat basophilic leukemia cells have frequently been employed for investigating the pathways of leukotriene biosynthesis, a class of biologically active arachidonic acid metabolites. However, information is lacking on the levels of selenium-dependent glutathione peroxidase (Se-GSH-Px), non-Se-GSH-Px and glutathione S-transferases (GSH-S-Trs), key enzymes involved in fatty acid hydroperoxide metabolism and leukotriene biosynthesis in these cells. Both GSH-S-Trs and non-Se-GSH-Px reactions are catalyzed by the same enzyme. In the present studies, we have measured the enzyme activities of GSH-Px(s) and GSH-S-Trs in the 105,000 X g supernatant fraction of sonified RBL-1 cells. The specific activities for GSH-Px(s) toward H2O2, cumene hydroperoxide, and 15S-hydroperoxy-eicosatetraenoic acid (15S-HPETE) are 12.6, 17.9 and 26.9 nmoles X min-1 X mg-1 protein, respectively. A specific activity of 18.9 nmoles X min-1 X mg-1 protein with 1-chloro-2,4-dinitrobenzene was estimated for the GSH-S-Trs. Therefore, the cell fraction that exhibits 5-lipoxygenase activity also contains selenium and non-selenium glutathione peroxidases.
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PMID:Measurement of glutathione requiring enzymes involved in arachidonic acid cascade of rat basophilic leukemia cells. 644 77

Various substituted isoquinoline-1-carboxaldehyde thiosemicarbazones (12 compounds) have been synthesized and evaluated for antineoplastic activity in mice bearing the L1210 leukemia. Condensation of 4-bromo-1-methylisoquinoline (4) with ammonium hydroxide, methylamine, ethylamine, and N-acetylethylenediamine gave the corresponding 4-amino, 4-methylamino, 4-ethylamino, and 4-N-(acetylethyl)amino derivatives, which were then converted to amides and subsequently oxidized to aldehydes followed by condensation with thiosemicarbazide to yield thiosemicarbazones 8a-c, 9a-c, and 16. Nitration of 4, followed by oxidation with selenium dioxide, produced aldehyde 18, which was then converted to the cyclic ethylene acetal 19. Condensation of 19 with morpholine followed by catalytic reduction of the nitro group and treatment with thiosemicarbazide afforded 5-amino-4-morpholinoisoquinoline-1-carboxaldehyde thiosemicarbazone (22). N-Oxidation of 1,5-dimethylisoquinoline, followed by rearrangement with acetic anhydride, gave, after acid hydrolysis, 1,5-dimethyl-4-hydroxyisoquinoline, which was converted to its acetate and then oxidized to yield 4-acetoxy-5-methylisoquinoline-1-carboxaldehyde (32). Sulfonation of 1,4-dimethylisoquinoline, followed by reaction with potassium hydroxide, acetylation, and oxidation, gave 5-acetoxy-4-methylisoquinoline-1-carboxaldehyde (40). Condensation of compounds 32 and 39 with thiosemicarbazide afforded the respective 4- and 5-acetoxy(5- and 4-methyl)thiosemicarbazones 33 and 40, which were then converted to their respective 4- and 5-hydroxy derivatives 34 and 41 by acid hydrolysis. The most active compounds synthesized were 4-aminoisoquinoline-1-carboxaldehyde thiosemicarbazone (9a) and 4-(methylamino)isoquinoline-1-carboxaldehyde thiosemicarbazone (9b), which both produced optimum % T/C values of 177 against the L1210 leukemia in mice when used at a daily dosage of 40 mg/kg for 6 consecutive days. Furthermore, when 9a was given twice daily at a dosage of 40 mg/kg for 6 consecutive days, a T/C value of 165 was obtained and 60% of the mice were 60-day long-term survivors.
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PMID:Synthesis and antitumor activity of 4- and 5-substituted derivatives of isoquinoline-1-carboxaldehyde thiosemicarbazone. 747 50

Merocyanine derivatives were prepared by structural alterations at the barbituric acid or chalcogenazole moieties. The photophysical properties of the dyes were markedly influenced by the presence of selenium rather than sulfur as a substituent at position 2 of the barbiturate. In methanol, quantum yields of both triplet state (phi T) and singlet oxygen sensitization (phi delta) were increased by over an order of magnitude, with a concomitant decrease in fluorescence, when selenium was present in the molecule. Photoisomerization, one of the dominant deactivation pathways in the sulfur- or oxygen-containing analogues, was completely absent in the selenium-containing derivatives. Efficient triplet state formation was observed for selenium-containing derivatives incorporated into L1210 cells by diffuse reflectance laser flash photolysis. Cytotoxicity studies, carried out using clonogenic assays on L1210 leukemia cells, showed a good correlation with phi T and phi delta, measured in solution. Experimental evidence provided by this paper supports a triplet state-, and probably singlet oxygen-, mediated phototoxic mechanism. Photoisomerization or singlet state mechanisms can be discounted.
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PMID:Merocyanine dyes: effect of structural modifications on photophysical properties and biological activity. 752 61

Murine L1210 and human HL-60 leukemia cells grown for 5-7 days in medium containing 1% serum without selenium supplementation [Se(-) cells] were severely depressed in selenoperoxidase (SePX) activity relative to selenium-supplemented controls [Se(+) cells]. Catalase (CAT) activity in Se(-) cells was unaffected up to this point, but thereafter began to increase. Two manifestations of this increase have been differentiated for both cell lines: (a) short-term induction of CAT (up to approx. twofold) after 2-3 weeks, followed by (b) long-term selection for cells that irreversibly express much higher levels of CAT, e.g., > 100 times (L1210) and > 10 times (HL-60) the levels observed in Se(+) controls after approximately 20 weeks. Although superoxide dismutase, glutathione S-transferase, and glucose-6-P dehydrogenase activities were unchanged in Se(-) cells, GSH levels were elevated by 50-100%; like short-term CAT elevation, this could be reversed by supplying Se. Short-term Se(-) cells were more sensitive to H2O2-induced killing than Se(+) cells, evidently because SePX activity was important for peroxide detoxification. However, long-term Se(-) cells were markedly more resistant to H2O2 than Se(+) counterparts, consistent with the much higher levels of CAT in the former. Southern blot analysis revealed that the copy number of CAT DNA in a clone of long-term Se(-) L1210 cells was four- to fivefold greater than that in an Se(+) clone. Northern blot analysis of RNA from the same Se(-) clone showed a CAT mRNA level that was at least 40 times higher than that of the Se(+) control. Similar trends were observed for HL-60 cells. These results suggest that elevated CAT during long-term Se deprivation is a reflection of amplification and greater transcription of the CAT gene.
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PMID:Amplification and hyperexpression of the catalase gene in selenoperoxidase-deficient leukemia cells. 787 6


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