PT  - JOURNAL ARTICLE
AU  - Markus Grube
AU  - Sebastian Reuther
AU  - Henriette Meyer zu Schwabedissen
AU  - Kathleen Köck
AU  - Katrin Draber
AU  - Christoph A. Ritter
AU  - Christoph Fusch
AU  - Gabriele Jedlitschky
AU  - Heyo K. Kroemer
TI  - Organic Anion Transporting Polypeptide 2B1 and Breast Cancer Resistance Protein Interact in the Transepithelial Transport of Steroid Sulfates in Human Placenta
AID  - 10.1124/dmd.106.011411
DP  - 2007 Jan 01
TA  - Drug Metabolism and Disposition
PG  - 30--35
VI  - 35
IP  - 1
4099  - http://dmd.aspetjournals.org/content/35/1/30.short
4100  - http://dmd.aspetjournals.org/content/35/1/30.full
SO  - Drug Metab Dispos2007 Jan 01; 35
AB  - The human placenta has both protective and nurturing functions for the fetal organism. Uptake and elimination of xenobiotics and endogenous substances are facilitated by various transport proteins from the solute carrier (SLC) and ABC families, respectively. A functional interaction of uptake and elimination, which is a prerequisite for vectorial transport across cellular barriers, has not been described for placenta. In this study, we examined expression of organic anion transporter (OAT) 4 (SLC22A11), organic anion transporting polypeptide (OATP) 2B1 (SLCO2B1, OATP-B), and breast cancer resistance protein (BCRP) (ABCG2) in human placenta (n = 71) because all three proteins are involved in transmembranal transfer of estrone 3 sulfate (E3S; metabolic product) and dehydroepiandrosterone sulfate (DHEAS; precursor molecule). On the mRNA level, we found a significant correlation of OATP2B1 and BCRP (R2 = 0.534; p < 0.01) but not between OAT4 and BCRP (R2 = –0.104; p > 0.05). Localization studies confirmed basal expression of OATP2B1 and apical expression of BCRP. To study functional interactions between OATP2B1 and BCRP, we developed a Madin-Darby canine kidney cell model expressing both transport proteins simultaneously (OATP2B1 and BCRP in the basal and apical membrane, respectively). Using this cell model in a transwell system resulted in a significantly increased basal to apical transport of both E3S and DHEAS, when both transporters were expressed with no change of transfer in the apical to basal direction. Taken together, these data show the potential for a functional interaction of OATP2B1 and BCRP in transepithelial transport of steroid sulfates in human placenta. The American Society for Pharmacology and Experimental Therapeutics