Directional trans-epithelial transport of organic anions in porcine LLC-PK1 cells that co-express human OATP1B1 (OATP-C) and MRP2.
The transcellular transport of many compounds, which cannot readily cross the lipid bilayer, is mediated by drug uptake and efflux transporters. Human OATP1B1 and MRP2 have been implicated in the hepato-biliary transport of many endogenous and exogenous compounds. Here, we have established epithelial porcine kidney LLC-PK1 derived cell lines, that express both transporters in a polarized fashion, as a model to predict hepato-biliary transport. Immunological identification of OATP1B1 in the recombinant cell lines was greatly facilitated by its C-terminal tagging with a peptide sequence derived from hemagglutinin (HA) avoiding the generation of OATP1B1 specific antibodies. Importantly, the tag did not interfere with the functionality of the transporter. Compared to LLC-PK1 cells and cells which expressed only OATP1B1, the cell line that co-expressed MRP2 and OATP1B1 displayed high directional basolateral-to-apical transport of 17 beta-estradiol-17 beta-glucuronide and estrone-3-sulfate. Dehydroepiandrosterone sulfate already displayed a significant basolateral-to-apical transport in the parental cell line, which was further stimulated upon expression of both transporters. Transcellular flux of all steroid conjugates in the opposite direction (apical-to-basolateral) was much lower. By employing this cellular model we were able to demonstrate for the first time that OATP1B1 together with MRP2 mediates the trans-cellular transport of rifampicin. It is anticipated that the models established herein will greatly facilitate the identification of transporters involved in the disposition of novel drug candidates.
Spears
Kevin J
KJ
Biomedical Research Centre, University of Dundee, Ninewells Hospital and Medical School, Dundee DD1 9SY, UK.
Ross
Jillian
J
Stenhouse
Alasdair
A
Ward
Clive J
CJ
Goh
Lay-Beng
LB
Wolf
C Roland
CR
Morgan
Paul
P
Ayrton
Andy
A
Friedberg
Thomas H
TH
D000818:Animals; D001692:Biological Transport; D004848:Epithelium / Q000378:metabolism; D004958:Estradiol / Q000493:pharmacokinetics; D004970:Estrone / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D027381:Liver-Specific Organic Anion Transporter 1 / Q000502:physiology*; D026901:Membrane Transport Proteins / Q000502:physiology*; D000089762:Multidrug Resistance-Associated Protein 2; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000502:physiology*; D012293:Rifampin / Q000493:pharmacokinetics; D013552:Swine; D014162:Transfection
D004958:Estradiol; D004970:Estrone; D027381:Liver-Specific Organic Anion Transporter 1; D026901:Membrane Transport Proteins; D000089762:Multidrug Resistance-Associated Protein 2; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D012293:Rifampin; C000715087:ABCC2 protein, human; C017296:estrone sulfate