The ATP-dependent glutathione S-conjugate export pump

Ishikawa, Toshihisa

doi:10.1016/0968-0004(92)90489-v

Cited by 578 publications

(349 citation statements)

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“…BSO is a specific inhibitor of GSH synthesis and its known effects on cells can be attributed to the decrease in cellular GSH caused by the block in GSH synthesis (23 (12), the multispecific organic anion transporter (MOAT) (13), or the LTC4 transporter (9,10 Why MRP-overexpressing cells secrete so much GSH is unclear. In experiments with isolated plasma membrane vesicles, GSH did not inhibit the ATP-dependent transport of LTC4 or dinitrophenylglutathione by MRP (11,12). However, this does not exclude the possibility that GSH is a low-affinity substrate for MRP or that GSH is transported together with an endogenous ligand.…”

Section: Discussionmentioning

confidence: 99%

“…This suggests that MRP is a GS-X pump (12) present in many, if not all, mammalian cells (9-13). These pumps transport substrates containing a large hydrophobic moiety and at least two negative charges (12,13), as present in drug GSH Sconjugates. Moreover, recent studies indicate that GS-X pumps are also involved in the export of cisplatin (14)(15)(16) and arsenite (11).…”

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Role of glutathione in the export of compounds from cells by the multidrug-resistance-associated protein.

Zaman

Lankelma

Tellingen

et al. 1995

Proc. Natl. Acad. Sci. U.S.A.

435

298

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Multidrug-resistance-associated protein [6][7][8] and is able to decrease cellular drug levels against a concentration gradient (4, 6). However, recent work has also indicated interesting differences between MRP and Pgp. Increased cellular MRP levels are associated with increased reduced glutathione (GSH) S-conjugate carrier (GS-X pump) activity in isolated plasma membrane vesicles (9-11). This suggests that MRP is a GS-X pump (12) present in many, if not all, mammalian cells (9-13). These pumps transport substrates containing a large hydrophobic moiety and at least two negative charges (12, 13), as present in drug GSH Sconjugates. Moreover, recent studies indicate that GS-X pumps are also involved in the export of cisplatin (14-16) and arsenite (11). Indeed, some cell lines overexpressing MRP are moderately resistant to arsenite (4, 11). These results link MRP to older experiments in which resistance to anthracyclines was found to correlate with increased levels of cellular GSH, GSH synthesis, or GSH Stransferases (17)(18)(19). This link is supported by the strong decrease in drug resistance in two MDR lung carcinoma cell lines that overexpress MRP by DL-buthionine (S,R)-sulfoximine (BSO) (20)(21)(22), an inhibitor of y-glutamylcysteine synthetase, the enzyme that catalyzes the first step in GSH synthesis (23). The interpretation of these inhibitor experiments is not unambiguous, however. In both cell lines, other resistance mechanisms (e.g., alterations in topoisomerase II) contribute to resistance, and it is not clear whether the GSH depletion in these cells does not result in membrane damagee.g., by lipid peroxidation. Damage of the plasma membrane could increase drug influx and, hence, decrease resistance. To test whether GSH is specifically required for MDR caused by MRP but not by Pgp, we have analyzed the effects of BSO treatment on lung cancer cells transfected with an expression vector containing either MRP cDNA or MDR1 cDNA. MATERIALS AND METHODSCell Lines. S1(MRP) was obtained after transfection of non-small cell lung cancer SW-1573/S1 cells with an expression vector containing MRP cDNA and a neomycin-resistance marker gene (pRc/RSV-MRP), followed by selection with geneticin (G418) (6). Sl(MDR1) was previously named S1(1.1) (24) and was obtained after transfection of S1 cells with the expression vector pJ3fl (25) containing MDR1 cDNA, followed by selection with 10 nM vincristine. GLC4/ADR is a MRP-overexpressing subline of the non-small cell lung cancer cell line GLC4 and was obtained by selection with doxorubicin (20,21).Clonogenic Survival Assay. In six-well dishes, 400 cells per well were seeded and incubated in medium with or without 25 ,uM BSO for 24 hr prior to incubation with increasing concentrations of drug. After 1 hr, drug was removed, the wells were rinsed with phosphate-buffered saline, and drug-free medium without BSO was added. Seven days after the start of the experiment, the percentage of cells that were able to produce a colony of >50 cells was used as a measure of cell sur...

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Role of glutathione in the export of compounds from cells by the multidrug-resistance-associated protein.

Zaman

Lankelma

Tellingen

et al. 1995

Proc. Natl. Acad. Sci. U.S.A.

435

298

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“…Conjugation with the nucleophilic thiol group of the tripeptide glutathione (GSH) at the electrophilic centers of activated PAH renders their reactive groups such as epoxides less toxic, more water-soluble and hence more readily excretable [5,6]. Conjugation with GSH also flags toxic chemicals for export via plasma membrane efflux transporters, a step that is often required to complete the detoxification process [7,8]. Thus, GST expression is thought to play an important role in the prevention of the cytotoxicity, mutagenicity, and/or carcinogenicity resulting from PAHs in the environment [9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Cytotoxicity and mutagenicity of dibenzo[a,l]pyrene and (±)-dibenzo[a,l]pyrene-11,12-dihydrodiol in V79MZ cells co-expressing either hCYP1A1 or hCYP1B1 together with human glutathione-S-transferase A1

Kushman

Kabler

Ahmad

et al. 2007

Mutation Research/Fundamental and Molecular Mechanisms of Mutag

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We have used V79MZ hamster lung fibroblasts stably transfected with human cytochrome P450-1A1 (hCYP1A1; cell line designated V79MZh1A1) or P450-1B1 (hCYP1B1; cell line designated V79MZh1B1) alone, or in combination with human GST alpha-1 (hGSTA1), in order to examine GST protection against cytotoxicity and mutagenicity of dibenzo [a,l]pyrene (DBP) and the intermediate dihydrodiol metabolite (+/−)- . At comparable expression levels of hCYP1A1 and hCYP1B1, both DBP and DBPD were more cytotoxic in V79MZ1A1 (IC 50 = 2.7 nM and 0.7 nM, respectively) than in V79MZh1B1 (IC 50 = 6.0 nM and 4.8 nM, respectively). In contrast, both DBP and DBPD were 2-fold to 4-fold more mutagenic in V79MZh1B1 than in V79MZ1A1. Co-expression of hGSTA1 with hCYP1A1 decreased DBP cytotoxicity 2-fold compared to V79MZh1A1 with hCYP1A1 alone, and provided a small, yet still statistically significant, 1.3-fold protection against DBPD. Protection against mutagenicity of these compounds was comparable to that for cytotoxicity in cells expressing hCYP1A1. In V79MZh1B1 cells, co-expression of hGSTA1 conferred up to 5-fold protection against DBP cytotoxicity, and up to 9-fold protection against the (+/−)-DBP-dihydrodiol cytotoxicity relative to the cells expressing hCYP1B1 alone. Co-expression of hGSTA1 also reduced mutagenicity of DBP or its dihydrodiol to a lesser extent (1.3-fold to 1.8-fold) than the protection against cytotoxicity in cells expressing hCYP1B1. These findings demonstrate that the protective efficacy of hGSTA1 against DBP and DBPD toxicity is variable, depending on the compound or metabolite present, the specific cytochrome P450 isozyme expressed, and the specific cellular damage endpoint examined.Keywords glutathione transferase; cytochrome P-450; polycyclic aromatic hydrocarbon; cytotoxicity; mutagenicity; transfection *Corresponding Author: Alan J. Townsend, Ph.D., Biochemistry Department, Wake Forest University School of Medicine, Medical Center Blvd., Winston-Salem N.C. 27157, Phone (336)-713-7215; FAX (336)-716-7671, E-mail: atown@wfubmc.edu. Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. . These reactive products include diol-epoxides with potent mutagenic and carcinogenic activity, some of which are substrates for conjugation by isozymes of the glutathione-S-transferase (GST) superfamily of genes [5]. Conjugation with the nucleophilic thiol group of the tripeptide glutathione (GSH) at the electrophilic centers of activated PAH renders their reactive groups such as epoxides less toxic, more water-soluble and hence more readily excretable [5,6]. Conjugation with GSH also fla...

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“…Transporters with these characteristics are known as glutathione conjugate (GS-X) pumps (Ishikawa, 1992), or multispecific organic anion transporters . Besides organic anions MRP1 can also transport neutral and basic cytotoxic drugs not known to be conjugated to GSH or other negatively charged compounds Zaman et al, 1994).…”

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confidence: 99%

Vinblastine and sulfinpyrazone export by the multidrug resistance protein MRP2 is associated with glutathione export

et al. 2000

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SummaryThe multidrug resistance proteins MRP1 and MRP2 are members of the same subfamily of ATP-binding cassette transporters. Besides organic molecules conjugated to negatively charged ligands, these proteins also transport cytotoxic drugs for which no negatively charged conjugates are known to exist. In polarized MDCKII cells, MRP1 routes to the lateral plasma membrane, and MRP2 to the apical plasma membrane. In these cells MRP1 transports daunorubicin, and MRP2 vinblastine; both transporters export reduced glutathione (GSH) into the medium. We demonstrate that glutathione transport in MDCKII-MRP1 cells is inhibited by the inhibitors of organic anion transporters sulfinpyrazone, indomethacin, probenecid and benzbromarone. In MDCKII-MRP2 cells, GSH export is stimulated by low concentrations of sulfinpyrazone or indomethacin, whereas export is inhibited down to control levels at high concentrations. We find that unmodified sulfinpyrazone is a substrate for MRP2, also at concentrations where GSH export is inhibited. We also show that GSH export in MDCKII-MRP2 cells increases in the presence of vinblastine, and that the stochiometry between drug and GSH exported is between two and three. Our data indicate that transport of sulfinpyrazone and vinblastine is associated with GSH export. However, at high sulfinpyrazone concentrations this compound is transported without GSH. Models of MRP action are discussed that could explain these results.

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The ATP-dependent glutathione S-conjugate export pump

Cited by 578 publications

References 24 publications

Role of glutathione in the export of compounds from cells by the multidrug-resistance-associated protein.

Role of glutathione in the export of compounds from cells by the multidrug-resistance-associated protein.

Cytotoxicity and mutagenicity of dibenzo[a,l]pyrene and (±)-dibenzo[a,l]pyrene-11,12-dihydrodiol in V79MZ cells co-expressing either hCYP1A1 or hCYP1B1 together with human glutathione-S-transferase A1

Vinblastine and sulfinpyrazone export by the multidrug resistance protein MRP2 is associated with glutathione export

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