ATP-dependent efflux of calcein by the multidrug resistance protein (MRP): no inhibition by intracellular glutathione depletion

FEBS Lett. 1995 Jul 17;368(2):385-8. doi: 10.1016/0014-5793(95)00677-2.


In this study we report that the multidrug resistance protein (MRP) transports calcein from the cytoplasmic compartment of tumor cells, in contrast to P-glycoprotein which transports calcein acetoxymethyl ester from the plasmamembrane. The transport of calcein by MRP is ATP-dependent and is inhibited by probenecid and vincristine. Intracellular glutathione (GSH) depletion which occurred when cells were exposed to buthionine sulfoximine had no effect on the efflux of calcein, whereas it reversed the daunorubicin accumulation deficit in MRP overexpressing tumor cells. In conclusion, ATP-dependent transport of calcein and possibly other organic anions by MRP is not inhibited by a large decrease of the intracellular GSH concentration, that inhibits daunorubicin efflux by MRP.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • ATP Binding Cassette Transporter, Subfamily B, Member 1 / physiology
  • ATP-Binding Cassette Transporters / metabolism*
  • Adenosine Triphosphate / physiology*
  • Biological Transport, Active / drug effects
  • Buthionine Sulfoximine
  • Cytoplasm / metabolism
  • Daunorubicin / metabolism
  • Fluoresceins / metabolism*
  • Glutathione / physiology*
  • Humans
  • Indicators and Reagents / metabolism*
  • Methionine Sulfoximine / analogs & derivatives
  • Methionine Sulfoximine / pharmacology
  • Multidrug Resistance-Associated Proteins
  • Neoplasm Proteins / metabolism*
  • Probenecid / pharmacology
  • Tumor Cells, Cultured


  • ATP Binding Cassette Transporter, Subfamily B, Member 1
  • ATP-Binding Cassette Transporters
  • Fluoresceins
  • Indicators and Reagents
  • Multidrug Resistance-Associated Proteins
  • Neoplasm Proteins
  • calcein AM
  • Methionine Sulfoximine
  • Buthionine Sulfoximine
  • Adenosine Triphosphate
  • Glutathione
  • Probenecid
  • fluorexon
  • Daunorubicin