Document Detail

Evidence for functional discrimination between leukemic cells overexpressing multidrug-resistance associated protein and P-glycoprotein.
MedLine Citation:
PMID:  10500790     Owner:  NLM     Status:  MEDLINE    
Multidrug-resistance (MDR), caused by overexpression of either P-glycoprotein (Pgp) or the multidrug-resistance associated protein (MRP), is characterised by a decreased cellular drug accumulation. One form of MDR is the sequestration of the drug inside cytoplasmic vesicles followed by an a exocytotic and/or efflux process. In some studies, increased intracellular glutathione (GSH) has been associated with MDR. In this study, we examined the effects of 7-chloro-4-nitrobenz-2-oxa-1,3-diazole or NBD (a H(+)-ATPase pump inhibitor) and buthionine sulphoximine or BSO (an inhibitor of GSH biosynthesis) on the subcellular distribution of daunorubicin or DNR in two leukemic homoharringtonine-resistant K562 cell lines, overexpressing MRP (K-H30) and Pgp (K-H300). DNR nuclear accumulation was carried out using microspectrofluorometry. Our results show that DNR nuclear accumulation and sensitivity of K-H30 cells were increased by NBD and BSO whereas in K-H300 cells, NBD and BSO were unable to increase the DNR nuclear accumulation and sensitivity of these cells. This study demonstrates clearly that even if vesicular sequestration can happen in cells overexpressing MRP and Pgp proteins, only the MRP protein is able to extrude the drug through intracellular vesicles and efflux. In addition, GSH plays an important part in the pathway of drug transport in cells overexpressing MRP. Data entrain also the notion of functional discrimination between the MDR and MRP phenotype.
Z Benderra; H Morjani; A Trussardi; M Manfait
Publication Detail:
Type:  Comparative Study; Journal Article    
Journal Detail:
Title:  Advances in experimental medicine and biology     Volume:  457     ISSN:  0065-2598     ISO Abbreviation:  Adv. Exp. Med. Biol.     Publication Date:  1999  
Date Detail:
Created Date:  1999-11-04     Completed Date:  1999-11-04     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0121103     Medline TA:  Adv Exp Med Biol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  151-60     Citation Subset:  IM    
Laboratoire de Spectroscopie Biomoléculaire, IFR 53, EA 2063, UFR de Pharmacie, Reims, France.
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MeSH Terms
ATP-Binding Cassette Transporters / genetics*,  metabolism
Buthionine Sulfoximine / toxicity
Cell Nucleus / metabolism
Cell Survival / drug effects*
Clone Cells
Daunorubicin / pharmacokinetics,  toxicity*
Drug Resistance, Multiple*
Genes, MDR
Glutathione / metabolism
K562 Cells
Microscopy, Confocal / methods
Multidrug Resistance-Associated Proteins
P-Glycoprotein / genetics*,  metabolism
Reverse Transcriptase Polymerase Chain Reaction
Reg. No./Substance:
0/ATP-Binding Cassette Transporters; 0/Multidrug Resistance-Associated Proteins; 0/P-Glycoprotein; 20830-81-3/Daunorubicin; 5072-26-4/Buthionine Sulfoximine; 70-18-8/Glutathione

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