DNA Binding, DNA Photocleavage, Molecular Docking Studies and Photo-Induced Effect on Melanoma Cells of 2-Methyl-3-OR Quinazolinone Derivatives

Thirty 2-methyl-quinazolinone fussed hydroxamic acids (3-OH) and their 3-OEt and 3-OBn derivatives were evaluated for their affinity towards calf-thymus (CT) DNA using UV-vis absorption, viscosity and fluorescence spectroscopy. DNA photocleavage activity was assessed by incubating the compounds with plasmid DNA followed by UV-A and visible light irradiation, which enabled identification of the most potent derivatives active at concentrations of 100 nΜ and 10 μΜ, respectively. Mechanistic studies on the most active compounds indicated the formation of oxygen radical species and a decrease in efficiency under argon. Measurements of singlet oxygen release verified these findings. Molecular docking studies provided further insight into the interactions between the compounds and DNA. UV-A irradiation of the most potent DNA photocleavers in three cell lines, two malignant melanoma lines (A375 and COLO-800) and the immortalized keratinocyte line HaCaT, identified three derivatives that, at a concentration up to 10 μΜ, reduced cell viability by approximately 50%. Taken together, these results indicate that these 2-methylquinazolinone-based hydroxamic acid derivatives are promising candidates for the development of photodynamic therapy agents.