Glutathione Homeostasis in Human Hepatic Cells: Overexpression of γ-Glutamylcysteine Synthetase Gene in Cell Lines Resistant to Buthionine Sulfoximine, an Inhibitor of Glutathione Synthesis

1998 ◽  
Vol 246 (2) ◽  
pp. 398-403 ◽  
Author(s):  
Toshiya Tanaka ◽  
Takeshi Uchiumi ◽  
Kimitoshi Kohno ◽  
Akira Tomonari ◽  
Kazuto Nishio ◽  
...  
Keyword(s):  
Cell Lines ◽  
Buthionine Sulfoximine ◽  
Glutathione Synthesis ◽  
Hepatic Cells ◽  
Glutamylcysteine Synthetase ◽  
Glutathione Homeostasis

scholarly journals Regulation of intracellular glutathione levels in erythrocytes infected with chloroquine-sensitive and chloroquine-resistant Plasmodium falciparum

2002 ◽  
Vol 368 (3) ◽  
pp. 761-768 ◽  
Author(s):  
Svenja MEIERJOHANN ◽  
Rolf D. WALTER ◽  
Sylke MÜLLER
Keyword(s):  
Oxidative Stress ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Differential Susceptibility ◽  
Protozoan Parasite ◽  
Chloroquine Resistance ◽  
Glutathione Metabolism ◽  
Glutathione Synthesis ◽  
Intracellular Glutathione ◽  
Glutamylcysteine Synthetase

Malaria is one of the most devastating tropical diseases despite the availability of numerous drugs acting against the protozoan parasite Plasmodium in its human host. However, the development of drug resistance renders most of the existing drugs useless. In the malaria parasite the tripeptide glutathione is not only involved in maintaining an adequate intracellular redox environment and protecting the cell against oxidative stress, but it has also been shown that it degrades non-polymerized ferriprotoporphyrin IX (FP IX) and is thus implicated in the development of chloroquine resistance. Glutathione levels in Plasmodium-infected red blood cells are regulated by glutathione synthesis, glutathione reduction and glutathione efflux. Therefore the effects of drugs that interfere with these metabolic processes were studied to establish possible differences in the regulation of the glutathione metabolism of a chloroquine-sensitive and a chloroquine-resistant strain of Plasmodiumfalciparum. Growth inhibition of P. falciparum 3D7 by d,l-buthionine-(S,R)sulphoximine (BSO), an inhibitor of γ-glutamylcysteine synthetase (γ-GCS), and by Methylene Blue (MB), an inhibitor of gluta thione reductase (GR), was significantly more pronounced than inhibition of P.falciparum Dd2 growth by these drugs. These results correlate with the higher levels of total glutathione in P. falciparum Dd2. Short-term incubations of Percoll-enriched trophozoite-infected red blood cells in the presence of BSO, MB and N,N1-bis(2-chloroethyl)-N-nitrosourea and subsequent determinations of γ-GCS activities, GR activities and glutathione disulphide efflux revealed that maintenance of intracellular glutathione in P. falciparum Dd2 is mainly dependent on glutathione synthesis whereas in P. falciparum 3D7 it is regulated via GR. Generally, P. falciparum Dd2 appears to be able to sustain its intracellular glutathione more efficiently than P. falciparum 3D7. In agreement with these findings is the differential susceptibility to oxidative stress of both parasite strains elicited by the glucose/glucose oxidase system.

Involvement of reactive oxygen species in adaphostin-induced cytotoxicity in human leukemia cells

Blood ◽  
2003 ◽  
Vol 102 (13) ◽  
pp. 4512-4519 ◽  
Author(s):  
Joya Chandra ◽  
Jennifer Hackbarth ◽  
Son Le ◽  
David Loegering ◽  
Nancy Bone ◽  
...  
Keyword(s):  
Cell Lines ◽  
Buthionine Sulfoximine ◽  
Lymphocytic Leukemia ◽  
Myelogenous Leukemia ◽  
Glutathione Depletion ◽  
Leukemia Cells ◽  
Clinical Samples ◽  
Human Leukemia ◽  
Lymphoid Leukemia

Abstract Adaphostin (NSC 680410), an analog of the tyrphostin AG957, was previously shown to induce Bcr/abl down-regulation followed by loss of clonogenic survival in chronic myelogenous leukemia (CML) cell lines and clinical samples. Adaphostin demonstrated selectivity for CML myeloid progenitors in vitro and remained active in K562 cells selected for imatinib mesylate resistance. In the present study, the mechanism of action of adaphostin was investigated in greater detail in vitro. Initial studies demonstrated that adaphostin induced apoptosis in a variety of Bcr/abl- cells, including acute myelogenous leukemia (AML) blasts and cell lines as well as chronic lymphocytic leukemia (CLL) samples. Further study demonstrated that adaphostin caused intracellular peroxide production followed by DNA strand breaks and, in cells containing wild-type p53, a typical DNA damage response consisting of p53 phosphorylation and up-regulation. Importantly, the antioxidant N-acetylcysteine (NAC) blunted these events, whereas glutathione depletion with buthionine sulfoximine (BSO) augmented them. Collectively, these results not only outline a mechanism by which adaphostin can damage both myeloid and lymphoid leukemia cells, but also indicate that this novel agent might have a broader spectrum of activity than originally envisioned. (Blood. 2003;102:4512-4519)

Interactions of nitroglycerin and sulfhydryl-donating compounds in coronary microvessels

1994 ◽  
Vol 266 (1) ◽  
pp. H291-H297 ◽  
Author(s):  
R. M. Wheatley ◽  
S. P. Dockery ◽  
M. A. Kurz ◽  
H. S. Sayegh ◽  
D. G. Harrison
Keyword(s):  
Redox Potential ◽  
Potent Inhibitor ◽  
Buthionine Sulfoximine ◽  
Glutathione Synthesis ◽  
Endothelin 1 ◽  
Intracellular Glutathione ◽  
Enzymatic Bioconversion

Previous studies have shown the effect of nitroglycerin on coronary microvessels < 100 microns in diameter is markedly enhanced by L-cysteine. These studies were performed to examine the mechanisms responsible for this effect. Under control conditions, nitroglycerin caused potent dilations of large (> 200 microns diam) coronary microvessels while having minimal effects on small (< 100 microns diam) coronary microvessels [peak relaxations 85 +/- 4 vs. 23 +/- 3% (mean +/- SE) of endothelin-1-constricted vessels, respectively]. L-Cysteine (100 microM) and N-acetylcysteine (100 microM) markedly enhanced nitroglycerin-induced relaxations of small coronary microvessels (peak relaxation 84 +/- 6 and 87 +/- 12%, respectively) while having no effect on relaxations of vessels > 100 microns. In contrast, neither L-methionine (100 microM) nor glutathione (100 microM) enhanced nitroglycerin's vasodilation of small coronary microvessels. The effects of L-cysteine and N-acetylcysteine on the augmentation of nitroglycerin vasodilatation in smaller coronary microvessels was abolished in the presence of buthionine sulfoximine (100 microM), a potent inhibitor of intracellular glutathione synthesis. Buthionine sulfoximine had no effect on the vasodilatation produced by nitroprusside. These data demonstrate that, in smaller coronary microvessels, L-cysteine and N-acetylcysteine enhance nitroglycerin-induced vasodilatation by increasing intracellular glutathione concentrations. Intracellular glutathione, formed from either L-cysteine or N-acetylcysteine, may participate in the formation of an intermediate of nitroglycerin biotransformation or may maintain a redox potential within coronary microvessels that favors enzymatic bioconversion of nitroglycerin.

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