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Human Hepatobiliary Transport of Organic Anions Analyzed by Quadruple-Transfected Cells
Hepatobiliary elimination of many organic anions is initiated by OATP1B1 (OATP2, LST-1, OATP-C), OATP1B3 (OATP8), and OATP2B1 (OATP-B), which are the predominant uptake transporters of human hepatocytes. Thereafter, the unidirectional efflux pump ABCC2 (multidrug resistance protein 2) mediates the t...
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Published in: | Molecular pharmacology 2005-10, Vol.68 (4), p.1031-1038 |
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Main Authors: | , , , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | Hepatobiliary elimination of many organic anions is initiated by OATP1B1 (OATP2, LST-1, OATP-C), OATP1B3 (OATP8), and OATP2B1
(OATP-B), which are the predominant uptake transporters of human hepatocytes. Thereafter, the unidirectional efflux pump ABCC2
(multidrug resistance protein 2) mediates the transport of organic anions, including glutathione conjugates and glucuronosides,
into bile. In this study, we generated a Madin-Darby canine kidney (MDCKII) cell line stably expressing recombinant OATP1B1,
OATP1B3, and OATP2B1 in the basolateral membrane and ABCC2 in the apical membrane. Double-transfected MDCKII cells stably
expressing ABCC2 together with OATP1B1, OATP1B3, or OATP2B1 served as control cells. The quadruple-transfected cells exhibited
high rates of vectorial transport of organic anions, including bromosulfophthalein, cholecystokinin peptide (CCK-8), and estrone
3-sulfate. The quadruple-transfected cells enabled the identification of substrates for uptake or vectorial transport that
may be missed in studies with a double-transfected cell line, as exemplified by CCK-8, which is a substrate for OATP1B3 but
not for OATP1B1 or OATP2B1. The broad substrate spectrum covered by the three hepatocellular OATP transporters enables representative
analyses of the uptake of many organic anions into human hepatocytes. The broad spectrum of organic anions transported vectorially
by the quadruple-transfected cells also provides valuable information on the substrate selectivity of ABCC2, without the need
for studies in inside-out membrane vesicles containing the ABCC2 protein. The quadruple-transfected MDCKII-ABCC2/OATP1B1/1B3/2B1
cells may thus be useful for the identification of substrates and inhibitors, including drug candidates, undergoing uptake
and secretion by human hepatocytes, under conditions that may be better defined than in primary cultures of human hepatocytes. |
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ISSN: | 0026-895X 1521-0111 |
DOI: | 10.1124/mol.105.014605 |