Selective Targeting of Cancer-Related G-Quadruplex Structures by the Natural Compound Dicentrine

Aiming to identify highly effective and selective G-quadruplex ligands as anticancer candidates, five natural compounds were investigated here, i.e., the alkaloids Canadine, D-Glaucine and Dicentrine, as well as the flavonoids Deguelin and Millettone, selected as analogs of compounds previously identified as promising G-quadruplex-targeting ligands. A preliminary screening with the G-quadruplex on the Controlled Pore Glass assay proved that, among the investigated compounds, Dicentrine is the most effective ligand of telomeric and oncogenic G-quadruplexes, also showing good G-quadruplex vs. duplex selectivity. In-depth studies in solution demonstrated the ability of Dicentrine to thermally stabilize telomeric and oncogenic G-quadruplexes without affecting the control duplex. Interestingly, it showed higher affinity for the investigated G-quadruplex structures over the control duplex (K-b similar to 10(6) vs. 10(5) M-1), with some preference for the telomeric over the oncogenic G-quadruplex model. Molecular dynamics simulations indicated that Dicentrine preferentially binds the G-quadruplex groove or the outer G-tetrad for the telomeric and oncogenic G-quadruplexes, respectively. Finally, biological assays proved that Dicentrine is highly effective in promoting potent and selective anticancer activity by inducing cell cycle arrest through apoptosis, preferentially targeting G-quadruplex structures localized at telomeres. Taken together, these data validate Dicentrine as a putative anticancer candidate drug selectively targeting cancer-related G-quadruplex structures.

Automated summary

In this study, five natural compounds were investigated as analogs of promising G-quadruplex-targeting ligands to identify highly effective and selective anticancer candidates. Among them, Dicentrine was found to be the most effective ligand for telomeric and oncogenic G-quadruplexes, showing good selectivity. In-depth studies demonstrated that Dicentrine thermally stabilizes G-quadruplexes without affecting the control duplex, with higher affinity for G-quadruplex structures. Molecular dynamics simulations indicated that Dicentrine preferentially binds the G-quadruplex groove or the outer G-tetrad. Biological assays confirmed that Dicentrine promotes potent and selective anticancer activity by inducing cell cycle arrest through apoptosis, targeting G-quadruplex structures at telomeres.