Antitumor activity and selectivity of a nanostructured peroxo polyoxoniobate

In vitro and in vivo experiments were carried out to evaluate the activity and antitumor selectivity of new niobium oligomers. A polyoxoniobate (PONb) structure linked to the methylene blue dye (PONb-MB) showed promising results for some types of tumor cells. Molecular structures were determined for PONb and PONb-MB based on spectroscopic analyses using density functional theory calculations. Both caused a significant cell viability reduction in tumor cells (HeLa) with high effectiveness, because of the reactivity oxygen species (ROS) generated on their chemical structure. Experimental quantitative analysis demonstrated high selectivity for tumor cells (apoptosis 3× higher compared to MRC-5 healthy cells). Lower toxicities in healthy cells (e.g., MRC-5 and L929) confirm the selectivity of the synthesized compounds. It is noteworthy that PONb and PONb-MB are physiologically soluble compounds and can be suitable for intravenous treatments. Biodistribution studies in mice revealed very low accumulation in organs such as the spleen, heart, liver, lungs, and kidneys. Additionally, almost no toxicity was observed in the mice post-injection, which was confirmed by biochemical analysis.