Transport of phosphatidylcholine in MDR3-negative epithelial cell lines via drug-induced MDR1 P-glycoprotein.
Human MDR1 P-glycoprotein (P-gp) is a membrane efflux pump for cytotoxics, whereas MDR3 P-gp is a phosphatidylcholine transporter. We have examined a role for MDR1 P-gp in phosphatidylcholine transport in MDR3-negative epithelial cells that have been induced to express the MDR1 P-gp by exposure to cytotoxics. The accumulation and retention of the fluorescently labelled phosphatidylcholine analogue, C12-NBD-PC, was studied in resistant, KBV1 and MCFadr, and sensitive, KB3-1 and MCF7, cells. Lower accumulation and decreased retention of C12-NBD-PC was evident in resistant cells, e.g., KBV1 accumulated 56%, and MCFadr accumulated 60%, of C12-NBD-PC levels in KB3-1 and MCF7, respectively. Treatment with the MDR1 P-gp inhibitor, verapamil, altered the kinetics of C12-NBD-PC in the resistant cells to more closely follow the pattern of C12-NBD-PC handling by sensitive cells. Comparison of C12-NBD-PC to that of the model MDR1 P-gp substrate, rhodamine-123, indicated phosphatidylcholine turnover kinetics by MDR1 P-gp to be relatively low. The transport by MDR1 P-gp of phosphatidylcholine from inner to outer membrane leaflet may regulate P-gp function and fulfill a role in the MDR1 multidrug-resistant phenotype.
Abulrob
A G
AG
Welsh School of Pharmacy, Cardiff University, Cardiff, CF10 3XF, United Kingdom.
Gumbleton
M
M
D009327:4-Chloro-7-nitrobenzofurazan / Q000031:analogs & derivatives* / Q000378:metabolism; D018435:ATP Binding Cassette Transporter, Subfamily B / Q000235:genetics / Q000378:metabolism*; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D018528:ATP-Binding Cassette Transporters / Q000235:genetics / Q000378:metabolism*; D001692:Biological Transport / Q000187:drug effects; D004317:Doxorubicin / Q000378:metabolism; D019008:Drug Resistance, Neoplasm; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism*; D005434:Flow Cytometry; D005456:Fluorescent Dyes / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D010641:Phenotype; D010713:Phosphatidylcholines / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics; D020112:Rhodamine 123 / Q000378:metabolism; D014407:Tumor Cells, Cultured; D014700:Verapamil / Q000494:pharmacology*
D018435:ATP Binding Cassette Transporter, Subfamily B; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D018528:ATP-Binding Cassette Transporters; D005456:Fluorescent Dyes; D010713:Phosphatidylcholines; D012333:RNA, Messenger; C067460:1-oleoyl-2-(12-((7-nitro-2,1,3-benzoxadiazol-4-yl)amino)dodecanoyl)phosphatidylcholine; D020112:Rhodamine 123; D004317:Doxorubicin; C095122:multidrug resistance protein 3; D014700:Verapamil; D009327:4-Chloro-7-nitrobenzofurazan