Functional expression of P-glycoprotein in an immortalised cell line of rat brain endothelial cells, RBE4.
The presence of P-glycoprotein in the cell plasma membrane limits the penetration of many cytotoxic substances into cells that express the gene product. There is considerable evidence also to indicate that P-glycoprotein is expressed as part of the normal blood-brain barrier in the luminal membranes of the cerebral capillary endothelial cells, where it presumably performs a protective function for the brain. This report describes the functional expression of P-glycoprotein in an immortalised cell line, RBE4, derived from rat cerebral capillary endothelial cells. The expression of P-glycoprotein is demonstrated by western immunoblotting and by immunogold and fluorescent staining with monoclonal antibodies. The cellular accumulation of [3H]colchicine and [3H]-vinblastine is investigated and shown to be enhanced by the presence of azidothymidine, chlorpromazine, verapamil, cyclosporin A, and PSC 833 ([3'-keto-Bmt1]-[Val2]-cyclosporin) at 50 or 100 microM concentration. It is concluded that the RBE4 cell line is a valuable tool for investigating the mechanisms of P-glycoprotein activity both in the blood-brain barrier and in multidrug resistance in general.
Begley
D J
DJ
Biomedical Sciences Division, King's College London, England.
Lechardeur
D
D
Chen
Z D
ZD
Rollinson
C
C
Bardoul
M
M
Roux
F
F
Scherman
D
D
Abbott
N J
NJ
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000096:biosynthesis* / Q000502:physiology*; D000818:Animals; D001692:Biological Transport / Q000502:physiology; D001921:Brain / Q000166:cytology*; D002460:Cell Line; D002461:Cell Line, Transformed / Q000187:drug effects / Q000378:metabolism; D003078:Colchicine / Q000493:pharmacokinetics; D004727:Endothelium / Q000378:metabolism; D006801:Humans; D015151:Immunoblotting; D007150:Immunohistochemistry; D007624:KB Cells / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D014407:Tumor Cells, Cultured / Q000378:metabolism; D014747:Vinblastine / Q000493:pharmacokinetics
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D014747:Vinblastine; D003078:Colchicine