Identification of novel functional organic anion-transporting polypeptide 1B3 polymorphisms and assessment of substrate specificity
- 1 March 2011
- journal article
- research article
- Published by Ovid Technologies (Wolters Kluwer Health) in Pharmacogenetics and Genomics
- Vol. 21 (3), 103-114
- https://doi.org/10.1097/fpc.0b013e328342f5b1
Abstract
The uptake carrier organic anion-transporting polypeptide 1B3 (OATP1B3, gene SLCO1B3) is involved in the hepatic clearance of xenobiotics including statins, taxanes, and mycophenolic acid. We thought to assess the SLCO1B3 coding region for yet unidentified polymorphisms and to analyze their functional relevance. We used DNA of ethnically diverse individuals for polymerase chain reaction, and determined polymorphisms by sequencing or temperature-dependent capillary electrophoresis. We then created variant OATP1B3 expression plasmids by site-directed mutagenesis, which were transiently expressed and functionally characterized in human cervical carcinoma (HeLa) cells using radiolabeled substrates. We identified six nonsynonymous polymorphisms including novel variants such as 439A>G (Thr147Ala), 767G>C (Gly256Ala), 1559A>C (His520Pro), and 1679T>C (Val560Ala). Allelic frequencies occurred to be ethnicity-dependent, with the latter observed only in African–Americans (3.6%). After expression in HeLa cells, His520Pro, Val560Ala, and Met233Ile or Met233Ile_Ser112Ala haplotype variants showed decreased uptake activity compared with wild type for cholecystokinin-8 and rosuvastatin, but not for atorvastatin. Kinetic cholecystokinin-8 analysis showed reduced V max without altering K m. His520Pro and Val560Ala exhibited decreased total and plasma membrane protein expressions. Val560 mapped onto a structural model of OATP1B3 showed that this is a key region for substrate–transporter interaction. His520 resides in a predicted extracellular region thought to be critical to the pH-dependent component of OATP1B3 activity. Loss of activity at pH 7.4 and 8.0 relative to pH 6.5 was significantly greater for the Pro520 variant. OATP1B3 polymorphisms that result in altered expression, substrate specificity, and pH-dependent activity may be of potential relevance to hepatic clearance of substrate drugs in vivo.Keywords
This publication has 32 references indexed in Scilit:
- SLCO1B1 variants and statin-induced myopathy - A genomewide studyThe New England Journal of Medicine, 2008
- Amino Acid Residues in Transmembrane Domain 10 of Organic Anion Transporting Polypeptide 1B3 Are Critical for Cholecystokinin Octapeptide TransportBiochemistry, 2008
- Effect of SLCO1B3 Haplotype on Testosterone Transport and Clinical Outcome in Caucasian Patients with Androgen-Independent Prostatic CancerClinical Cancer Research, 2008
- Influence of SLCO1B1, 1B3, 2B1 and ABCC2 genetic polymorphisms on mycophenolic acid pharmacokinetics in Japanese renal transplant recipientsEuropean Journal of Clinical Pharmacology, 2007
- Effect of drug transporter genotypes on pravastatin disposition in European- and African-American participantsPharmacogenetics and Genomics, 2007
- Different Effects of SLCO1B1 Polymorphism on the Pharmacokinetics of Atorvastatin and RosuvastatinClinical Pharmacology & Therapeutics, 2007
- Variants in the SLCO1B3 Gene: Interethnic Distribution and Association with Paclitaxel PharmacokineticsClinical Pharmacology & Therapeutics, 2007
- Functional Analysis of the Extracellular Cysteine Residues in the Human Organic Anion Transporting Polypeptide, OATP2B1Molecular Pharmacology, 2006
- Polymorphisms and Linkage Disequilibrium of the OATP8 (OATP1B3) Gene in Japanese SubjectsDrug Metabolism and Pharmacokinetics, 2006
- Identification of OATP1B3 as a high-affinity hepatocellular transporter of paclitaxelCancer Biology & Therapy, 2005