In vitro evaluation of the selective cytotoxicity and genotoxicity of three synthetic ortho-nitrobenzyl derivatives in human cancer cell lines, with and without metabolic activation

Although the presence of nitro groups in chemicals can be recognized as structural alerts for mutagenicity and carcinogenicity, nitroaromatic compounds have attracted considerable interest as a class of agents that can serve as source of potential new anticancer agents. In the present study, the in vitro cytotoxicity, genotoxicity, and mutagenicity of three synthetic ortho-nitrobenzyl derivatives (named ON-1, ON-2 and ON-3) were evaluated by employing human breast and ovarian cancer cell lines. A series of biological assays was carried out with and without metabolic activation. Complementarily, computational predictions of the pharmacokinetic properties and druglikeness of the compounds were performed in the Swiss ADME platform. The MTT assay showed that the compounds selectively affected selectively the cell viability of cancer cells in comparison with a nontumoral cell line. Additionally, the metabolic activation enhanced cytotoxicity, and the compounds affected cell survival, as demonstrated by the clonogenic assay. The comet assay, the cytokinesis-block micronucleus assay, and the immunofluorescence of the gamma-H2AX foci formation assay have that the compounds caused chromosomal damage to the cancer cells, with and without metabolic activation. The results obtained in the present study showed that the compounds assessed were genotoxic and mutagenic, inducing double-strand breaks in the DNA structure. The high selectivity indices observed for the compounds ON-2 and ON-3, especially after metabolic activation with the S9 fraction, must be highlighted. These experimental biological results, as well as the theoretical properties predicted for the compounds have shown that they are promising anticancer candidates to be exploited in additional studies.