Recent Update on Targeting G-Quadruplexes by Small Molecules for Anticancer Therapeutics.

Guanine-rich DNA sequences have the propensity to adopt four-stranded tetrahelical G-quadruplex (G4) structures that are overrepresented in gene promoters. The structural polymorphism and physicochemical properties of these non-Watson-Crick G4 structures make them important targets for drug development. The guanine-rich nuclease hypersensitivity element III present in the upstream of P1 promoter of oncogene has the ability to form an intramolecular parallel G4 structure. The G4 structure that forms transiently in the promoter functions as a transcriptional repressor element. The oncogene is overexpressed in a wide variety of cancers and plays a key role in cancer progression. Till now, a large number of compounds that are capable of interacting and stabilizing the G4 have been reported. In this review, we summarize various G4 specific molecules and discuss their effects on gene expression and .