Verapamil-stimulated glutathione transport by the multidrug resistance-associated protein (MRP1) in leukaemia cells.

Cullen, KV; Davey, RA; Davey, MW

Verapamil-stimulated glutathione transport by the multidrug resistance-associated protein (MRP1) in leukaemia cells.

Cullen, KV Davey, RA Davey, MW

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Publication Type:: Journal Article
Citation:: Biochem Pharmacol, 2001, 62 (4), pp. 417 - 424
Issue Date:: 2001-08-15

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Field	Value	Language
dc.contributor.author	Cullen, KV	en_US
dc.contributor.author	Davey, RA	en_US
dc.contributor.author	Davey, MW	en_US
dc.date.issued	2001-08-15	en_US
dc.identifier.citation	Biochem Pharmacol, 2001, 62 (4), pp. 417 - 424	en_US
dc.identifier.issn	0006-2952	en_US
dc.identifier.uri	http://hdl.handle.net/10453/4436
dc.description.abstract	Multidrug resistance mediated by the multidrug resistance-associated protein MRP1 is associated with decreased drug accumulation, which is in turn dependent on cellular glutathione. We have reported that verapamil, an inhibitor of drug transport, caused a decrease in cellular glutathione in CCRF-CEM/E1000 MRP1-overexpressing leukaemia cells (Biochem Pharmacol 55;1283--9, 1998). We now demonstrate that other inhibitors of MRP1-mediated drug transport (e.g. MK571, indomethacin, genistein, and nifedipine) deplete cellular glutathione in these leukaemia cells (>30% decrease; P < 0.01) while having no effect on the parental CCRF-CEM cells. However, treatment with etoposide or vincristine (at similar molar concentrations) caused a 20% decrease in glutathione. Verapamil-stimulated glutathione transport correlated with MRP1 expression in a series of drug-resistant cells, and glutathione was quantitatively recovered in the extracellular media. Further, verapamil-stimulated glutathione transport was rapid (50% decrease in 10 min), dose-dependent, and inhibited by vanadate, an inhibitor of ATPase activity, but not by sulphobromophthalein (BSP) or methionine, inhibitors of hepatic glutathione transporters. Incubation of CCRF-CEM/E1000 cells in 25 mM glutathione not only showed that verapamil-mediated efflux occurred against the concentration gradient, but also demonstrated the MRP1-mediated uptake of glutathione (P < 0.01 compared to the parental CCRF-CEM cells), which was not inhibited by vanadate. These results demonstrate that while MRP1 transports glutathione in the presence of inhibitors of drug transport, there is no convincing evidence for co-transport of glutathione with drug. They further demonstrate that MRP1 mediates the facilitated transport of glutathione into the MRP1-overexpressing CEM/E1000 cells, suggesting that MRP1 may play a major role in cellular glutathione homeostasis.	en_US
dc.language	eng	en_US
dc.relation.ispartof	Biochem Pharmacol	en_US
dc.relation.isbasedon	10.1016/s0006-2952(01)00681-5	en_US
dc.subject.classification	Pharmacology & Pharmacy	en_US
dc.subject.mesh	Tumor Cells, Cultured	en_US
dc.subject.mesh	Humans	en_US
dc.subject.mesh	Leukemia	en_US
dc.subject.mesh	Verapamil	en_US
dc.subject.mesh	Glutathione	en_US
dc.subject.mesh	ATP-Binding Cassette Transporters	en_US
dc.subject.mesh	Multidrug Resistance-Associated Proteins	en_US
dc.subject.mesh	Calcium Channel Blockers	en_US
dc.subject.mesh	Biological Transport	en_US
dc.title	Verapamil-stimulated glutathione transport by the multidrug resistance-associated protein (MRP1) in leukaemia cells.	en_US
dc.type	Journal Article
utslib.citation.volume	4	en_US
utslib.citation.volume	62	en_US
utslib.location.activity	England	en_US
utslib.for	070708 Veterinary Parasitology	en_US
utslib.for	100302 Bioprocessing, Bioproduction and Bioproducts	en_US
utslib.for	060199 Biochemistry and Cell Biology not elsewhere classified	en_US
utslib.for	0601 Biochemistry and Cell Biology	en_US
utslib.for	1115 Pharmacology and Pharmaceutical Sciences	en_US
pubs.embargo.period	Not known	en_US
pubs.organisational-group	/University of Technology Sydney
pubs.organisational-group	/University of Technology Sydney/Faculty of Science
utslib.copyright.status	closed_access
pubs.issue	4	en_US
pubs.publication-status	Published	en_US
pubs.volume	62	en_US

Abstract:

Multidrug resistance mediated by the multidrug resistance-associated protein MRP1 is associated with decreased drug accumulation, which is in turn dependent on cellular glutathione. We have reported that verapamil, an inhibitor of drug transport, caused a decrease in cellular glutathione in CCRF-CEM/E1000 MRP1-overexpressing leukaemia cells (Biochem Pharmacol 55;1283--9, 1998). We now demonstrate that other inhibitors of MRP1-mediated drug transport (e.g. MK571, indomethacin, genistein, and nifedipine) deplete cellular glutathione in these leukaemia cells (>30% decrease; P < 0.01) while having no effect on the parental CCRF-CEM cells. However, treatment with etoposide or vincristine (at similar molar concentrations) caused a 20% decrease in glutathione. Verapamil-stimulated glutathione transport correlated with MRP1 expression in a series of drug-resistant cells, and glutathione was quantitatively recovered in the extracellular media. Further, verapamil-stimulated glutathione transport was rapid (50% decrease in 10 min), dose-dependent, and inhibited by vanadate, an inhibitor of ATPase activity, but not by sulphobromophthalein (BSP) or methionine, inhibitors of hepatic glutathione transporters. Incubation of CCRF-CEM/E1000 cells in 25 mM glutathione not only showed that verapamil-mediated efflux occurred against the concentration gradient, but also demonstrated the MRP1-mediated uptake of glutathione (P < 0.01 compared to the parental CCRF-CEM cells), which was not inhibited by vanadate. These results demonstrate that while MRP1 transports glutathione in the presence of inhibitors of drug transport, there is no convincing evidence for co-transport of glutathione with drug. They further demonstrate that MRP1 mediates the facilitated transport of glutathione into the MRP1-overexpressing CEM/E1000 cells, suggesting that MRP1 may play a major role in cellular glutathione homeostasis.

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http://hdl.handle.net/10453/4436