In Vitro Inhibition of Renal OCT2 and MATE1 Secretion by Antiemetic Drugs

The organic cation transporter 2 (OCT2) and multidrug and toxin extrusion protein 1 (MATE1) mediate the renal secretion of drugs. Recent studies suggest that ondansetron, a 5-HT(3) antagonist drug used to prevent nausea and vomiting, can inhibit OCT2- and MATE1-mediated transport. The purpose of this study was to test the ability of five 5-HT(3) antagonist drugs to inhibit the OCT2 and MATE1 transporters. The transport of the OCT2/MATE1 probe substrate ASP(+) was assessed using two models: (1) HEK293 kidney cells overexpressing human OCT2 or MATE1, and (2) MDCK cells transfected with human OCT2 and MATE1. In HEK293 cells, the inhibition of ASP(+) uptake by OCT2 listed in order of potency was palonosetron (IC(50): 2.6 μM) > ondansetron > granisetron > tropisetron > dolasetron (IC(50): 85.4 μM) and the inhibition of ASP(+) uptake by MATE1 in order of potency was ondansetron (IC(50): 0.1 μM) > palonosetron = tropisetron > granisetron > dolasetron (IC(50): 27.4 μM). Ondansetron (0.5–20 μM) inhibited the basolateral-to-apical transcellular transport of ASP(+) up to 64%. Higher concentrations (10 and 20 μM) of palonosetron, tropisetron, and dolasetron similarly reduced the transcellular transport of ASP(+). In double-transfected OCT2-MATE1 MDCK cells, ondansetron at concentrations of 0.5 and 2.5 μM caused significant intracellular accumulation of ASP(+). Taken together, these data suggest that 5-HT(3) antagonist drugs may inhibit the renal secretion of cationic drugs by interfering with OCT2 and/or MATE1 function.