Assessment of Amino Acid/Drug Transporters for Renal Transport of [18F]Fluciclovine (anti-[18F]FACBC) in Vitro
Abstract[18F]Fluciclovine (trans-1-amino-3-[18F]fluorocyclobutanecarboxylic acid; anti-[18F]FACBC), a positron emission tomography tracer used for the diagnosis of recurrent prostate cancer, is transported via amino acid transporters (AATs) with high affinity (Km: 97–230 μM). However, the mechanism underlying urinary excretion is unknown. In this study, we investigated the involvement of AATs and drug transporters in renal [18F]fluciclovine reuptake. [14C]Fluciclovine (trans-1-amino-3-fluoro[1-14C]cyclobutanecarboxylic acid) was used because of its long half-life. The involvement of AATs in [14C]fluciclovine transport was measured by apical-to-basal transport using an LLC-PK1 monolayer as model for renal proximal tubules. The contribution of drug transporters herein was assessed using vesicles/cells expressing the drug transporters P-glycoprotein (P-gp), breast cancer resistance protein (BCRP), multidrug resistance-associated protein 4 (MRP4), organic anion transporter 1 (OAT1), organic anion transporter 3 (OAT3) , organic cation transporter 2 (OCT2), organic anion transporting polypeptide 1B1 (OATP1B1), and organic anion transporting polypeptide 1B3 (OATP1B3). The apical-to-basal transport of [14C]fluciclovine was attenuated by l-threonine, the substrate for system alanine-serine-cysteine (ASC) AATs. [14C]Fluciclovine uptake by drug transporter-expressing vesicles/cells was not significantly different from that of control vesicles/cells. Fluciclovine inhibited P-gp, MRP4, OAT1, OCT2, and OATP1B1 (IC50 > 2.95 mM). Therefore, system ASC AATs may be partly involved in the renal reuptake of [18F]fluciclovine. Further, given that [18F]fluciclovine is recognized as an inhibitor with millimolar affinity for the tested drug transporters, slow urinary excretion of [18F]fluciclovine may be mediated by system ASC AATs, but not by drug transporters. View Full-Text
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Ono, M.; Baden, A.; Okudaira, H.; Kobayashi, M.; Kawai, K.; Oka, S.; Yoshimura, H. Assessment of Amino Acid/Drug Transporters for Renal Transport of [18F]Fluciclovine (anti-[18F]FACBC) in Vitro. Int. J. Mol. Sci. 2016, 17, 1730.
Ono M, Baden A, Okudaira H, Kobayashi M, Kawai K, Oka S, Yoshimura H. Assessment of Amino Acid/Drug Transporters for Renal Transport of [18F]Fluciclovine (anti-[18F]FACBC) in Vitro. International Journal of Molecular Sciences. 2016; 17(10):1730.Chicago/Turabian Style
Ono, Masahiro; Baden, Atsumi; Okudaira, Hiroyuki; Kobayashi, Masato; Kawai, Keiichi; Oka, Shuntaro; Yoshimura, Hirokatsu. 2016. "Assessment of Amino Acid/Drug Transporters for Renal Transport of [18F]Fluciclovine (anti-[18F]FACBC) in Vitro." Int. J. Mol. Sci. 17, no. 10: 1730.
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