TMPyP4 is a cationic porphyrin that intercalates into and stabilizes G-quadruplexes, which are formed by DNA and RNA sequences composed of blocks of guanine residues. In this way, TMPyP4 inhibits telomerase activity (IC50 ≤ 50 μM), blocking the clonogenic growth and migration of cancer cells in culture and in vivo. TMPyP4 also inhibits acetylcholinesterase at doses of 0.1 to 1.0 mM.
