title: pH-sensitive interaction of HMG-CoA reductase inhibitors (statins) with organic anion transporting polypeptide 2B1.
abstract: The human organic anion transporting polypeptide 2B1 (OATP2B1, SLCO2B1) is ubiquitously expressed and may play an important role in the disposition of xenobiotics. The present study aimed to examine the role of OATP2B1 in the intestinal absorption and tissue uptake of 3-hydroxy-3-methylglutaryl-Coenzyme A (HMG-CoA) reductase inhibitors (statins). We first investigated the functional affinity of statins to the transporter as a function of extracellular pH, using OATP2B1-transfeced HEK293 cells. The results indicate that OATP2B1-mediated transport is significant for rosuvastatin, fluvastatin and atorvastatin, at neutral pH. However, OATP2B1 showed broader substrate specificity as well as enhanced transporter activity at acidic pH. Furthermore, uptake at acidic pH was diminished in the presence of proton ionophore, suggesting proton gradient as the driving force for OATP2B1 activity. Notably, passive transport rates are predominant or comparable to active transport rates for statins, except for rosuvastatin and fluvastatin. Second, we studied the effect of OATP modulators on statin uptake. At pH 6.0, OATP2B1-mediated transport of atorvastatin and cerivastatin was not inhibitable, while rosuvastatin transport was inhibited by E-3-S, rifamycin SV and cyclosporine with IC(50) values of 19.7 ± 3.3 μM, 0.53 ± 0.2 μM and 2.2 ± 0.4 μM, respectively. Rifamycin SV inhibited OATP2B1-mediated transport of E-3-S and rosuvastatin with similar IC(50) values at pH 6.0 and 7.4, suggesting that the inhibitor affinity is not pH-dependent. Finally, we noted that OATP2B1-mediated transport of E-3-S, but not rosuvastatin, is pH sensitive in intestinal epithelial (Caco-2) cells. However, uptake of E-3-S and rosuvastatin by Caco-2 cells was diminished in the presence of proton ionophore. The present results indicate that OATP2B1 may be involved in the tissue uptake of rosuvastatin and fluvastatin, while OATP2B1 may play a significant role in the intestinal absorption of several statins due to their transporter affinity at acidic pH.
authors.affiliation: Pharmacokinetics Dynamics and Metabolism, Pfizer Global Research and Development, Pfizer Inc., Groton, Connecticut 06340, USA. manthena.v.varma@pfizer.com
authors.forename: Manthena V
authors.initials: MV
authors.lastname: Varma
authors.forename: Charles J
authors.initials: CJ
authors.lastname: Rotter
authors.forename: Jonathan
authors.initials: J
authors.lastname: Chupka
authors.forename: Kevin M
authors.initials: KM
authors.lastname: Whalen
authors.forename: David B
authors.initials: DB
authors.lastname: Duignan
authors.forename: Bo
authors.initials: B
authors.lastname: Feng
authors.forename: John
authors.initials: J
authors.lastname: Litchfield
authors.forename: Theunis C
authors.initials: TC
authors.lastname: Goosen
authors.forename: Ayman F
authors.initials: AF
authors.lastname: El-Kattan
mesh_terms: D000069059:Atorvastatin; D018938:Caco-2 Cells; D002460:Cell Line; D002853:Chromatography, Liquid; D004970:Estrone / Q000031:analogs & derivatives / Q000378:metabolism; D005229:Fatty Acids, Monounsaturated / Q000378:metabolism; D005464:Fluorobenzenes / Q000378:metabolism; D000077340:Fluvastatin; D006538:Heptanoic Acids / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000378:metabolism*; D007211:Indoles / Q000378:metabolism; D007408:Intestinal Absorption; D027361:Organic Anion Transporters / Q000235:genetics / Q000378:metabolism*; D011743:Pyrimidines / Q000378:metabolism; D011758:Pyrroles / Q000378:metabolism; D000068718:Rosuvastatin Calcium; D013449:Sulfonamides / Q000378:metabolism; D053719:Tandem Mass Spectrometry
chemical_list: D005229:Fatty Acids, Monounsaturated; D005464:Fluorobenzenes; D006538:Heptanoic Acids; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D007211:Indoles; D027361:Organic Anion Transporters; D011743:Pyrimidines; D011758:Pyrroles; C450859:SLCO2B1 protein, human; D013449:Sulfonamides; D004970:Estrone; D000077340:Fluvastatin; D000068718:Rosuvastatin Calcium; D000069059:Atorvastatin; C017296:estrone sulfate