Two new ligands (TPB3P and TPB3Py) showing a strong stabilisation effect and good selectivity for G4 over duplex DNAs have been synthesised. The ligands hold three analogous polyamine pendant arms (TPA3P and TPA3Py) but differ in the central aromatic core, which is a triphenylbenzene moiety instead of a triphenylamine moiety. Both TPB3P and TPB3Py exhibit high cytotoxicity in MCF-7, LN229 and HeLa cancer cells in contrast to TPA-based ligands, which exhibit no significant cytotoxicity. Moreover, the most potent G4 binders have been encapsulated in liposomes and AS1411 aptamer-targeted liposomes reaching nanomolar IC50 values for the most cytotoxic systems.
