(R)-KMH-233 is the isomer of KMH-233 , and can be used as an experimental control. KMH-233 , a potent, reversible and selective l-type amino acid transporter 1 (LAT1) inhibitor, inhibits the uptake of LAT1 substrate, l-leucin (IC 50 =18 μM) as well as cell growth. KMH-233 significantly potentiates the efficacy of Bestatin and Cisplatin even at low concentrations (25 μM).