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Evidence of P‐glycoprotein mediated apical to basolateral transport of flunisolide in human broncho‐tracheal epithelial cells (Calu‐3)
Author(s) -
Florea Bogdan I,
Van Der Sandt Inez C J,
Schrier S Mariette,
Kooiman Klazina,
Deryckere Koen,
De Boer Albertus G,
Junginger Hans E,
Borchard Gerrit
Publication year - 2001
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1038/sj.bjp.0704390
Subject(s) - p glycoprotein , apical membrane , sodium azide , membrane transport , chemistry , epithelial polarity , microbiology and biotechnology , biology , biochemistry , cell , membrane , multiple drug resistance , antibiotics
Transepithelial transport of flunisolide was studied in reconstituted cell monolayers of Calu‐3, LLC‐PK1 and the MDR1‐P‐glycoprotein transfected LLC‐MDR1 cells. Flunisolide transport was polarized in the apical (ap) to basolateral (bl) direction in Calu‐3 cells and was demonstrated to be ATP‐dependent. In LLC‐MDR1 cells, flunisolide was transported in the bl to ap direction and showed no polarization in LLC‐PK1 cells. Non‐specific inhibition of cellular metabolism at low temperature (4°C) or by 2‐deoxy‐ D ‐glucose (2‐d‐glu) and sodium azide (NaN 3 ) abolished the polarized transport. Polarized flunisolide transport was also inhibited by the specific Pgp inhibitors verapamil, SDZ PSC 833 and LY335979. Under all experimental conditions and in the presence of all used inhibitors, no decrease in the TransEpithelial Electrical Resistance (TEER) values was detected. From all inhibitors used, only the general metabolism inhibitors 2‐deoxy‐ D ‐glucose and NaN 3 , decreased the survival of Calu‐3 cells. Western blotting analysis and confocal laser scanning microscopy demonstrated the presence of MDR1‐Pgp at mainly the basolateral side of the plasma membrane in Calu‐3 cells and at the apical side in LLC‐MDR1 cells. Mass spectroscopy studies demonstrated that flunisolide is transported unmetabolized across Calu‐3 cells. In conclusion, these results show that the active ap to bl transport of flunisolide across Calu‐3 cells is facilitated by MDR1‐Pgp located in the basolateral plasma membrane.British Journal of Pharmacology (2001) 134 , 1555–1563; doi: 10.1038/sj.bjp.0704390