Identification of a multidrug resistance associated antigen (P-glycoprotein) in normal human tissues.
The multidrug resistance (NDR) phenotype describes a pattern of cross-resistance to unrelated compounds observed in mammalian cell lines selected in vitro for resistance to a single agent. Overexpression of a 170,000 dalton cell membrane glycoprotein (P-glycoprotein) is associated consistently with this phenotype in these cell lines. Recently, several human tumours have been shown to contain P-glycoprotein and expression was greatest in tumours exhibiting clinical drug resistance. To explore further the significance of P-glycoprotein, we examined normal human tissues obtained at autopsy by polyacrylamide gel electrophoresis and immunoblotting using a monoclonal antibody directed against P-glycoprotein. We showed expression of P-glycoprotein in normal liver and small bowel mucosa but not in other organs examined. This suggests there may be significant expression of P-glycoprotein in certain normal human tissues and any plan to exploit P-glycoprotein clinically must take these findings into account.
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000368:Aged; D002460:Cell Line; D004351:Drug Resistance; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D006801:Humans; D007158:Immunologic Techniques; D007421:Intestine, Small / Q000032:analysis; D008099:Liver / Q000032:analysis; D008297:Male; D008562:Membrane Glycoproteins / Q000032:analysis*; D008875:Middle Aged
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D008562:Membrane Glycoproteins