Expression of functionally P-glycoprotein in MA104 kidney cells.
Rhesus monkey kidney MA104 cells are a polarized epithelium with some unusual characteristics, including a resistance to ouabain, although their Na(+)-K(+)-ATPase has normal affinity with this drug. This work suggests that MA104 cells have high expression of functionally P-glycoprotein in their membranes. This was established using four complementary methods to investigate the expression and function of P-glycoprotein in these cells. MA104 cells were strongly resistant to vincristine, which could be reversed by three known P-glycoprotein modulators: verapamil, cyclosporin A and trifluoperazine. In addition, MA104 cells accumulate little rhodamine 123, and the incubation with verapamil increased this accumulation. The mdr1-mRNA was detected by reverse transcription-polymerase chain reaction and a subcloned 283-bp product was identified. Its nucleotide sequence was compared with the related region of human mdr1, showing a high identity (96%) between the two sequences. The expression of P-glycoprotein in the cell membrane was observed by Western blot and immunofluorescence. The results taken together suggest that MA104 cells intrinsically have a high expression of functionally P-glycoprotein in their membranes.
Capella
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Laboratório de Fisiologia Renal, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Brazil.
Orind
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Morales
M M
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Rumjanek
V M
VM
Lopes
A G
AG
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000096:biosynthesis / Q000235:genetics*; D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D018432:Drug Resistance, Multiple / Q000235:genetics*; D005786:Gene Expression Regulation; D006801:Humans; D007668:Kidney; D008253:Macaca mulatta; D008969:Molecular Sequence Data; D020133:Reverse Transcriptase Polymerase Chain Reaction; D020112:Rhodamine 123 / Q000493:pharmacokinetics; D016415:Sequence Alignment; D012689:Sequence Homology, Nucleic Acid; D014158:Transcription, Genetic; D014700:Verapamil / Q000494:pharmacology; D014750:Vincristine / Q000633:toxicity
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D020112:Rhodamine 123; D014750:Vincristine; D014700:Verapamil