P-glycoprotein expression in classical multi-drug resistant leukaemia cells does not correlate with enhanced chloride channel activity.
1. P-glycoprotein (Pgp) is an ATP-dependent drug efflux pump responsible for classical multi-drug resistance (MDR). 2. Pgp is part of a supergene family of membrane transport proteins that includes the cystic fibrosis gene product. 3. Transfection of cells with the MDR1 gene has been previously shown to generate volume-regulated chloride channel activity in association with Pgp expression. 4. We have used whole-cell patch clamping to examine the drug-sensitive T lymphoblastic cell line CEM-CCRF and its classical MDR derivative CEM/VLB100. The results suggest that expression of Pgp is not associated with increased chloride channel activity in this multi-drug resistant cell line. 5. We were unable to confirm previously reported results in MDR1 transfected cell lines that suggested that Pgp was associated with the presence of volume-regulated chloride channels.
Wang
X
X
Department of Physiology, University of Melbourne, Parkville, Australia.
Wall
D M
DM
Parkin
J D
JD
Zalcberg
J R
JR
Kemm
R E
RE
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000255:Adenosine Triphosphate / Q000494:pharmacology / Q000502:physiology; D002352:Carrier Proteins / Q000096:biosynthesis*; D018118:Chloride Channels / Q000187:drug effects / Q000378:metabolism*; D004351:Drug Resistance / Q000235:genetics*; D006801:Humans; D015458:Leukemia, T-Cell / Q000235:genetics / Q000378:metabolism*; D008562:Membrane Glycoproteins / Q000096:biosynthesis*; D008564:Membrane Potentials / Q000502:physiology; D014162:Transfection; D014407:Tumor Cells, Cultured
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D002352:Carrier Proteins; D018118:Chloride Channels; D008562:Membrane Glycoproteins; D000255:Adenosine Triphosphate