Light-Activated Molecules Targeting G-Quadruplex Nucleic Acids.

Phototherapies harness light's spatial and temporal precision to noninvasively modulate biomolecular interactions, providing a powerful platform for precision oncology. This approach is particularly effective in targeting disease-associated molecular structures such as G-quadruplexes (G4s), noncanonical nucleic acid conformations found in oncogene promoters and telomeres. These unique structures can impede DNA polymerase progression along the duplex, triggering DNA damage that ultimately compromises genomic stability. Stabilizing G4s with tailored ligands is currently being explored as a promising anticancer strategy, as it may induce toxic DNA damage specifically in rapidly dividing cancer cells. Unlike conventional G4 ligands, which remain continuously active, newly developed light-responsive molecules incorporate an OFF-ON switching mechanism that allows for spatiotemporal control over G4 dynamics and phototherapeutic effects. This concept article reviews a diverse array of light-responsive molecular tools, including photosensitizers (PSs), photocages, photochemically transformed ligands, and photoswitches, that selectively modulate G4-interactive binding properties, thereby laying the foundation for a versatile photopharmacological platform. Additionally, the article highlights recent advancements in this rapidly evolving field and discusses the challenges that remain for clinical translation, underscoring the significant potential of G4-targeted phototherapies to shape next-generation cancer treatments.