Internalization into cancer cells of zwitterionic amino acid polymers via amino acid transporter recognition

We synthesized lysine- and phenylalanine-based zwitterionic amino acid polymers (ZAPs) and evaluated their recognition capability for amino acid transporters (AATs), which are overexpressed on cancer cells as compared with normal cells. This study clearly demonstrates that ZAPs are internalized via AAT-mediated endocytosis with no cytotoxicity owing to their zwitterionic amino acid nature.