Linked Life Data

16499877

Source:http://linkedlifedata.com/resource/pubmed/id/16499877

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
8
pubmed:dateCreated
2006-3-13
pubmed:abstractText
It is now well-established that P-glycoprotein 170 (P-gp), an efflux pump involved in multidrug resistance (MDR) is overexpressed at the plasma membrane of doxorubicin-resistant K562 leukemia cells. Nevertheless, several results suggested: (i) that P-gp-mediated drug efflux was not the only mechanism involved in resistance; (ii) that intracellular compartments could accumulate the drug, preventing it from reaching its nuclear targets; (iii) that agents able to reverse multidrug resistance may lead to intracellular drug redistribution. We have studied the localization of P-gp in mitochondria as well as its functional properties in this compartment. Using several monoclonal antibodies (MoAbs) directed against different P-gp epitopes, a protein was detected in the cytoplasm of two doxorubicin-resistant K562 sublines and, by confocal laser scanning microscopy, this protein was shown to co-localize in the Golgi apparatus and in mitochondria, in equivalent proportions. Purified mitochondria were isolated from K562 cell variants; the presence of a protein of about 170 kDa and reacting with several anti-P-gp antibodies was assessed in MDR cells by Western blotting and flow cytometry. Functional assays have shown that mitochondrial P-gp was involved in doxorubicin accumulation inside the organelle but not in its efflux, suggesting an orientation of P-gp in the mitochondrial membrane inverse to that observed in the plasma membrane. A potential role for mitochondrial P-gp in MDR cells would be to protect the nucleus from doxorubicin. This is the first demonstration of the presence and functional activity of P-gp in mitochondria of MDR cells.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0006-2952
pubmed:author
pubmed:issnType
Print
pubmed:day
14
pubmed:volume
71
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1162-74
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2006
pubmed:articleTitle
Mitochondrial localization and activity of P-glycoprotein in doxorubicin-resistant K562 cells.
pubmed:affiliation
Laboratoire de Physiologie Mitochondriale, EA 3842 Faculté de Médecine, Limoges, France.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't