Inhibitory Interaction Potential of 22 Antituberculosis Drugs on Organic Anion and Cation Transporters of the SLC22A Family

Abstract

b Twenty-two currently marketed antituberculosis drugs were comprehensively evaluated for their inhibitory effect on organic anionic transporter (OAT)-and organic cation transporter (OCT)-mediated uptake using stably transfected HEK293 cells in vitro. We observed moderate to strong inhibitory effects on OAT1-and OAT3-mediated para-aminohippurate (PAH) uptake and OCT1-and OCT2-mediated N-methyl-4-phenylpylidinium acetate (MPP ؉ ) uptake. Ciprofloxacin, linezolid, para-aminosalicylic acid (PAS), and rifampin were observed to have strong inhibitory effects, with the concentrations for a 50% inhibitory effect (IC 50 s) being 35.1, 31.1, 37.6, and 48.1 M, respectively, for OAT1 and >100, 21.9, 24.6, and 30.2 M, respectively, for OAT3. Similarly, pyrazinamide, rifabutin, and levofloxacin were observed to have inhibitory effects, with IC 50 values being 36.5, 42.7, and 30.3 M, respectively, for OCT1 and with the IC 50 value for PAS being 94.2 M for OCT2. In addition, we used zidovudine and metformin as clinically prescribed substrates of OATs and OCTs, respectively, and zidovudine and metformin uptake was also strongly inhibited by the antituberculosis drugs. Among the tested drugs, the highest drug-drug interaction (DDI) indexes were found for PAS, which were 9.3 to 13.9 for OAT1 and 12.0 to 17.7 for OAT3, and linezolid, which were 1.18 to 2.15 for OAT1 and 1.7 to 3.01 for OAT3. Similarly, the DDI indexes of pyrazinamide and levofloxacin were 0.57 and 0.30, respectively, for OCT1, and the DDI index of PAS was 3.8 for OCT2, suggesting a stronger possibility (DDI index value cutoff, >0.1) of in vivo DDIs. This is the first comprehensive report of the inhibitory potential of anti-TB drugs on OAT-and OCT-mediated uptake of prototype and clinically prescribed substrate drugs in vitro, providing an ability to predict DDIs between anti-TB drugs and other coprescribed drugs in clinical studies in vivo. So far, 400 human solute carrier family (SLC) transporter proteins have been identified as a superfamily and have been classified into 52 different subfamilies (1). The organic cation transporter (OCT; SLC22 subfamily) and organic anion transporter (OAT; SLC22 subfamily) families play a major role in the disposition and pharmacology of drug substances (2). Among these, organic cation transporter OCT1 (SLC22A1) appears to be highly expressed in the liver of all species and in many tissues, although intriguing differences between species have been noted. OCT1 expression is restricted to the basolateral membrane of proximal tubular cells, with the greatest expression being apparent in an early segment (segment S1) of superficial, midcortical, and juxtamedullary nephrons (3), whereas OCT2 (SLC22A2) is expressed in the kidney and appears to be restricted to the basolateral membrane of proximal tubular cells (4).The function of OCTs includes mediation of the transport of organic cations into or out of cells. Not all but many organic cations (of endogenous and exogenous origin) are substrates of OCTs. Endogenous organic cations includ...

Evaluation of para -Aminosalicylic Acid as a Substrate of Multiple Solute Carrier Uptake Transporters and Possible Drug Interactions with Nonsteroidal Anti-inflammatory Drugs In Vitro

“…3), but its estimated DDI index value did not support the existence of a clinical DDI. This is in contrast to the findings described in a recently published study in which we reported a potential DDI between PAS and metformin and in which PAS inhibited metformin uptake via OCT1 and OCT2 in vitro (29). In this study, verapamil, cimetidine, and quinidine strongly inhibited PAS uptake via OCT1 and OCT2, and the DDI index values were much higher than the cutoff values (Table 2), indicating possible clinical DDIs.…”

“…Human embryonic kidney 293 (HEK) cells were stably transfected according to a previously reported method (34), and we have recently published the findings of a study using such stably transfected cells (29,31,35). In brief, stably transfected HEK-OCT1, HEK-OCT2, HEK-OAT1, HEK-OAT3, HEK-OATP1B1, HEK-OATP2B1, and HEK-OATP1B3 cells were grown in tissue culture flasks in Dulbecco's modified Eagle medium (DMEM) supplemented with 10% fetal bovine serum (FBS), 1% nonessential amino acids, 2 mM L-glutamine, and 100 U/ml penicillin-streptomycin (Invitrogen) at approximately 37°C in an atmosphere supplemented with 5% CO 2 .…”

“…However, the DDI index value that we determined failed to reach the cutoff value, suggesting that the DDI between PAS and NSAIDs has a negligible effect. We have previously published data on the inhibitory effect of PAS on OAT and OCT transporters, and it seems that these transporters are strongly associated with its uptake (29). Metformin is an inhibitor and substrate of OCTs and is extensively used to treat diabetes.…”

Potential Drug Interactions Mediated by Renal Organic Anion Transporter OATP4C1

“…We used the maximum plasma concentration (C max ) and the maximum concentration of unbound drug in plasma (C max,u ) for each drug and the IC 50 values from our in vitro study to predict the possibility of a clinical DDI, according to eq. 2 (Ito et al, 1998;Lau et al, 2007;CDER, 2012;Pan et al, 2013;Chioukh et al, 2014;Parvez et al, 2016):…”

Comprehensive Substrate Characterization of 22 Antituberculosis Drugs for Multiple Solute Carrier (SLC) Uptake Transporters In Vitro

“…4A). Previously, we also reported ethambutol inhibitory interactions with SLC transporters and drug-drug interaction potentials in vitro (35). Along with glomerular filtration, tubular secretion is also involved in ethambutol elimination from the kidney, as it has greater secretory clearance (36).…”