Metal Oxide Nanoparticles Having Strong Physico- and Electrochemical Interaction with Genetic Material Will Have Better Anticancer Efficacy

A mounting body of literature shows that interaction of metal oxide nanoparticles (MONPs) with biological macromolecules such as DNA is one of the vital mode of actions for their anticancer effect. Before promoting to clinical studies, it is critical to understand how MONPs interact with DNA at biologically effective concentrations. We have established IC₅₀ concentrations of three well-known MONPs against liver cancer cell line Huh-7, where silver oxide nanoparticles (AgONPs) were more sensitive than that of cerium oxide nanoparticles (CeONPs) and zinc oxide nanoparticles (ZnONPs). UV–visible spectroscopy was used to find out the association and mode of interaction, AgONPs showed groove binding nature whereas CeONPs and ZnONPs showed intercalation mode of binding with calf thymus DNA (CT-DNA). FTIR spectroscopy showed that there is only a slight variation in functional groups of the MONPs upon interaction with CT-DNA; however, they do not change the base groups of CT-DNA. Circular dichroism analysis revealed that there were no significant conformational changes in B-DNA form with all the three MONPs. In cyclic voltammetry, there were some electrochemical changes in the DNA after the addition of ZnONPs, positive shift of anodic peak was observed which indicated intercalation mode of DNA binding. Intercalator (EtBr) and groove binder (Hoechst) could not be displaced through ZnONPs and AgONPs, whereas CeONPs interaction replaced both dyes. Pretreatment with MONPs could prevent gamma irradiation induced DNA damage, whereas post-treatment was found to be ineffective. In vitro study indicated that DNA damage-mediated mechanism is the primary reason for these MONPs to induce anticancer effect. As observed through different spectroscopic techniques and DNA damage assay, interaction of MONPs with DNA is critical. AgONPs show more sensitivity due to their strong interaction with DNA than that of other two MONPs. So, modulation of AgONPs along with other MONPs to have more physical and chemical interaction with DNA is one of the aspect researchers should concentrate to increase anticancer efficacy of MONPs.