RT Journal Article
SR Electronic
T1 Impact of Experimental Conditions on the Evaluation of Interactions between Multidrug and Toxin Extrusion Proteins and Candidate Drugs
JF Drug Metabolism and Disposition
JO Drug Metab Dispos
FD American Society for Pharmacology and Experimental Therapeutics
SP 1381
OP 1389
DO 10.1124/dmd.115.068163
VO 44
IS 8
A1 Christian Lechner
A1 Naoki Ishiguro
A1 Ayano Fukuhara
A1 Hidetada Shimizu
A1 Naoko Ohtsu
A1 Masahito Takatani
A1 Kotaro Nishiyama
A1 Ikumi Washio
A1 Norio Yamamura
A1 Hiroyuki Kusuhara
YR 2016
UL http://dmd.aspetjournals.org/content/44/8/1381.abstract
AB Multidrug and toxin extrusion transporters (MATEs) have a determining influence on the pharmacokinetic profiles of many drugs and are involved in several clinical drug-drug interactions (DDIs). Cellular uptake assays with recombinant cells expressing human MATE1 or MATE2-K are widely used to investigate MATE-mediated transport for DDI assessment; however, the experimental conditions and used test substrates vary among laboratories. We therefore initially examined the impact of three assay conditions that have been applied for MATE substrate and inhibitor profiling in the literature. One of the tested conditions resulted in significantly higher uptake rates of the three test substrates, [14C]metformin, [3H]thiamine, and [3H]1-methyl-4-phenylpyridinium (MPP+), but IC50 values of four tested MATE inhibitors varied only slightly among the three conditions (<2.5-fold difference). Subsequently, we investigated the uptake characteristics of the five MATE substrates: [14C]metformin, [3H]thiamine, [3H]MPP+, [3H]estrone-3-sulfate (E3S), and rhodamine 123, as well as the impact of the used test substrate on the inhibition profiles of 10 MATE inhibitors at one selected assay condition. [3H]E3S showed atypical uptake characteristics compared with those observed with the other four substrates. IC50 values of the tested inhibitors were in a similar range (<4-fold difference) when [14C]metformin, [3H]thiamine, [3H]MPP+, or [3H]E3S were used as substrates but were considerably higher with rhodamine 123 (9.8-fold and 4.1-fold differences compared with [14C]metformin with MATE1 and MATE2-K, respectively). This study demonstrated for the first time that the impact of assay conditions on IC50 determination is negligible, that kinetic characteristics differ among used test substrates, and that substrate-dependent inhibition exists for MATE1 and MATE2-K, giving valuable insight into the assessment of clinically relevant MATE-mediated DDIs in vitro.