Abstract
Amino acid transporters are integrated membrane proteins that provide cells with nutrient amino acids. It is well established that subsets of amino acid transporters are highly expressed in cancers. A system L transporter LAT1 exhibits prominent expression in many cancers and its expression is inversely correlated with prognosis in some cancers. LAT1 is responsible for the uptake of large neutral amino acids including several essential amino acids. Functional coupling with ASCT2 which is also upregulated in cancers seems beneficial for LAT1 to be driven by intracellular glutamine accumulated by ASCT2 via an exchange mechanism. Now it has been demonstrated that a LAT1- selective ligand, L-[3-18F]-α-methyltyrosine (18F-FMT), is accumulated selectively in cancers in humans in a positron emission tomography (PET) in LAT1-depndent manner. [18F]FMT-PET can be a realistic diagnostic tool in the future. As expected from the roles of LAT1 in cancers, the inhibition of LAT1 results in the suppression of cancers. The newly developed high-affinity inhibitors of LAT1 are expected with therapeutic usefulness.
