New Ruthenium-Based Probes for Selective G-Quadruplex Targeting

Telomeric regions containing G-quadruplex (G4) structures play a pivotal role in the development of cancers. The development of specific binders for G4s is thus of great interest in order to gain a deeper understanding of the role of these structures, and to ultimately develop new anticancer drug candidates. For several years, Ru-II complexes have been studied as efficient probes for DNA. Interest in these complexes stems mainly from the tunability of their structures and properties, and the possibility of using light excitation as a tool to probe their environment or to selectively trigger their reaction with a biological target. Herein, we report on the synthesis and thorough study of new Ru-II complexes based on a novel dipyrazino[2,3-a:2',3'-h]phenazine ligand (dph), obtained through a Chichibabin-like reaction. Luminescence experiments, surface plasmon resonance (SPR), and computational studies have demonstrated that these complexes behave as selective probes for G-quadruplex structures.