Antitumor activity and selectivity of a unique nanostructured polyoxoniobate

In vitro and in vivo experiments were carried out to evaluate the activity and antitumor selectivity of new niobium oligomers. A polyoxoniobate (PONb) and its chemical 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 with density functional theory calculations. Both caused a significant cell viability reduction in tumor cells (HeLa) with high effectiveness of 10.0% at 10 mg L-1, because of the reactivity oxygen species (ROS) generated on its chemical structure. Experimental quantitative analyzes demonstrated high selectivity for tumor cells (apoptosis 3x higher compared to MRC-5 healthy cells). Lower toxicities for healthy cells (e.g., MRC-5 and L929) confirm the selectivity of the synthesized compounds. It is noteworthy that PONb-MB and PONb-MB are physiologically soluble compounds and can be suitable for intravenous treatments. Ex vivo biodistribution studies in mice revealed a 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 analyzes.