Enhanced and Persistent Inhibition of Organic Cation Transporter 1 Activity by Preincubation of Cyclosporine A

Abstract

Recent pharmacogenetic evidence indicates that hepatic organic cation transporter (OCT) 1 can serve as the locus of drug-drug interactions (DDIs) with significant pharmacokinetic and pharmacodynamic consequences. We examined the impact of preincubation on the extent of OCT1 inhibition in transfected human embryonic kidney 293 (HEK293) cells. Following 30-minute preincubation with an inhibitor, approximately 50-fold higher inhibition potency was observed for cyclosporine A (CsA) against OCT1mediated uptake of metformin compared with coincubation, with IC 50 values of 0.43 6 0.12 and 21.6 6 4.5 mM, respectively. By comparison, only small shifts (£2-fold) in preincubation IC 50 versus coincubation were observed for quinidine, pyrimethamine, ritonavir, and trimethoprim. The shift in CsA OCT1 IC 50 was substrate dependent since it ranged from >1.2to 50.2-fold using different experimental substrates. The inhibition potential of CsA toward OCT1 was confirmed by fenoterol hepatocyte uptake experiment. Furthermore, no shift in CsA IC 50 was observed with HEK293 cells transfected with OCT2 and organic anion transporter (OAT) 1 and OAT3. Short exposure (30 minutes) to 10 mM CsA produced longlasting inhibition (at least 120 minutes) of the OCT1-mediated uptake of metformin in OCT1-HEK293 cells, which was likely attributable to the retention of CsA in the cells, as shown by the fact that inhibitory cellular concentrations of CsA were maintained long after the removal of the compound from the incubation buffer. The potent and persistent inhibitory effect after exposure to CsA warrants careful consideration in the design and interpretation of clinical OCT1 DDI studies. SIGNIFICANCE STATEMENT Preincubation of OATP1B1 and OATP1B3 with their inhibitor may result in the enhancement of the inhibitory potency in a cell-based assay. However, limited data are available on potentiation of OCT1 inhibition by preincubation, which is a clinically relevant drug transporter. For the first time, we observed a 50-fold increase in CsA inhibitory potency against OCT1-mediated transport of metformin following a preincubation step. The CsA preincubation effect on OCT1 inhibition is substrate dependent. Moreover, the inhibition potential of CsA toward OCT1 is confirmed by hepatocyte uptake experiment. This study delivers clear evidences about the potent and persistent inhibitory effect on OCT1 after exposure to CsA. Further studies are needed to assess the effect of CsA on OCT1 drug substrates in vivo. This study was supported by the Bristol-Myers Squibb Company.

Functional and Pharmacological Comparison of Human, Mouse, and Rat Organic Cation Transporter 1 toward Drug and Pesticide Interaction

“… * Asterisks show the compounds which are already published to interact with hOCT1 but not with all rodent Oct1 [ 8 , 19 , 20 ]. …”

Inhibitory Effect of AB-PINACA, Indazole Carboxamide Synthetic Cannabinoid, on Human Major Drug-Metabolizing Enzymes and Transporters

“…The structural differences between APINACA and AB-PINACA or AB-FUBINACA are the adamantyl moiety for APINACA and amino-3-methyl-1-oxobutane moiety for AB-PINACA. Our literature review revealed that ritonavir and ledipasvir, which have 2-amino-3-methyl-1-oxobutyl residue, have been reported as inhibitors of OCT1 and OCT2 [35][36][37]. Therefore, we speculated the amino-3-methyl-1-oxobutane moiety in AB-PINACA may have inhibited OCT1 transporter in this study.…”

Assessing Trans-Inhibition of OATP1B1 and OATP1B3 by Calcineurin and/or PPIase Inhibitors and Global Identification of OATP1B1/3-Associated Proteins

“…This is consistent with a recent review in the International Transporter Consortium white paper [ 66 ] showing that kinase modulators are the most known post-translational mechanism involved in OATP1B1/3 regulation studied in the HEK293 system. Recent publications have shown that in addition to OATP1B1 and OATP1B3, trans -inhibition and/or time-dependent inhibition are observed for various solute carrier (SLC) uptake transporters such as OATs, OCTs, and multidrug and toxic compound extrusion (MATEs) [ 16 , 85 , 86 , 87 , 88 ], implying potential involvement of a common mechanism. The mechanisms underlying the common trans -inhibition and time-dependent inhibition of SLC transporters warrant investigation.…”

“…In addition to OATP1B1 and OATP1B3, trans -inhibition and/or time-dependent inhibition have been reported for various solute carrier uptake transporters such as OATs, OCTs, and multidrug and toxic compound extrusion (MATEs) [ 16 , 85 , 86 , 87 , 88 ], likely implying the involvement of one or more common mechanisms. Such a common mechanism does not exclude the possibility of shared, yet unidentified biological processes contributing to these similarities.…”