A dual approach for targeting LAT1 in cancer: Assay innovation and non-amino acid inhibitor development

About This Grant

Project summary: Amino acids are absorbed and utilized in the body with the help of dedicated transporters that are localized in the cell membranes. In cancer, the malignant cells often require a larger quantity of essential amino acids to survive, proliferate and metastasize thereby causing poor patient outcomes. Among the various transporters, L-amino acid transporter 1 (LAT1) is specifically overexpressed in many cancer cell types to meet the high demand. In contrast, most normal cells do not express LAT1. Clinically, the high expression of LAT1 has been associated with shorter survival in cancer patients. Thus, LAT1 inhibition is sought as a highly promising anti-cancer approach that can selectively target the malignant cells. However, all LAT1 inhibitors developed to date are based on an amino acid structure that results in toxic side effects and limitations relating to oral administration. Our primary goal is to create LAT1 selective inhibitors that have potent anti-cancer activity with fewer unwanted effects. Our design and development efforts will focus on non-amino acid compounds that inhibit LAT1 through a non-competitive mechanism without significant inhibitory effect on LAT2, LAT3, LAT4 or other transporters. In Aim 1, we will synthesize amino acid analogs that serve as broad LAT substrates that will be used in the development of new fluorescence-based assay systems for compound screening and inhibitor potency determinations. Concurrently, efforts will be dedicated to synthesizing the non-amino acid structures based on a monoterpene glycoside compound described previously in the literature. Aim 2 is focused on establishing stable LAT knock down and LAT over-expressing cancer cell lines to be used for validating the substrate transport activities and for screening of the non-amino compounds for inhibitory action. The data from this aim will reveal the structure activity relationship of the non-amino acid inhibitors. In Aim 3, the inhibitory compounds with the highest LAT1 selectivity will be tested for cellular anti-cancer activity using assays for proliferation, apoptosis, spheroid growth and intracellular signaling alterations.