Prediction of Organic Anion-Transporting Polypeptide 1B1- and 1B3-Mediated Hepatic Uptake of Statins Based on Transporter Protein Expression and Activity Data

Abstract

Organic anion-transporting polypeptides (OATP) 1B1 and OATP1B3 are drug transporters mediating the active hepatic uptake of their substrates. Because they exhibit overlapping substrate specificities, the contribution of each isoform to the net hepatic uptake needs to be considered when predicting drug-drug interactions. The relative contribution of OATP1B1-and OATP1B3-mediated uptake of statins into hepatocytes was estimated based on either relative transporter protein expression data or relative activity data. Therefore, kinetics of eight statins and OATP1B1-and OATP1B3-specific reference substrates was determined in OATP1B1-and OATP1B3-expressing human embryonic kidney 293 cells and in human cryopreserved hepatocytes. Absolute OATP1B1 and OATP1B3 protein abundance was determined by liquid chromatography-tandem mass spectrometry in all expression systems. Transporter activity data generated in recombinant cell lines were extrapolated to hepatocyte values using relative transporter expression factors (REF) or relative activity factors (RAF). Our results showed a pronounced OATP1B1 and comparatively low OATP1B3 protein expression in the investigated hepatocyte lot. Based on REF scaling, we demonstrated that the active hepatic uptake clearances of reference substrates, atorvastatin, pravastatin, rosuvastatin, and simvastatin were well predicted within twofold error, demonstrating that OATP1B1 and OATP1B3 were major contributors. For other statins, the net hepatic uptake clearance was underpredicted, suggesting the involvement of other hepatic uptake transporters. Summarized, we showed that REF-and RAF-based predictions were highly similar, indicating a direct transporter expressionactivity relationship. Moreover, we demonstrated that the REF-scaling method provided a powerful tool to quantitatively assess the transporterspecific contributions to the net uptake clearance of statins in hepatocytes.

Variability in hepatic expression of organic anion transporter 7/SLC22A9, a novel pravastatin uptake transporter: impact of genetic and regulatory factors

“…OATP1B1 and to a much lesser extent OATP1B3 have been identified as the important statin uptake transporters in hepatocytes, 29 but both transporters have been calculated to contribute, depending on the statin, only 20-80% to the hepatic uptake clearance of statins, in the case of pravastatin, 69-83%. 29,30 Our identification of OAT7 as a novel pravastatin transporter suggests that OAT7 may contribute to pravastatin disposition into the hepatocytes as well. We hypothesize that OAT7-mediated hepatic pravastatin uptake is ancillary when OATP1B1 and OATP1B3 are active.…”

The Influences of SLCO1B1 and ABCB1 Genotypes on the Pharmacokinetics of Simvastatin, in Relation to CYP3A4 Inhibition

“…First, due to our limited sample size, it was impossible to include more genetic polymorphisms in other lessstudied genes (such as SCLO1B3, CYP2D6, among others) [14,38]. Second, due to the low frequency of the SLCO1B1 c.521C/C genotype in the Korean population, we did not include the c.521C/C genotype and therefore we were unable to observe the potential gene-dose effect.…”

In Vitro-In Vivo Extrapolation Scaling Factors for Intestinal P-Glycoprotein and Breast Cancer Resistance Protein: Part I: A Cross-Laboratory Comparison of Transporter-Protein Abundances and Relative Expression Factors in Human Intestine and Caco-2 Cells

“…With this raft of abundance data generated across multiple laboratories now being incorporated into IVIVE-PBPK strategies (Bosgra et al, 2014;Kunze et al, 2014;Vildhede et al, 2014), it is critical to establish if laboratoryspecific methodologies contribute to a bias in abundance determination. To address this, membrane protein samples from human intestine and Caco-2 monolayers were analyzed independently by two laboratories, Bertin Pharma and the University of Manchester.…”