Cytotoxic effect of nanoceria on colon cancer cells (HT-29)

Abstract

Radiotherapy is commonly used for the treatment of colon cancer. Additionally, various antioxidant agents, such as nanoparticles of cerium oxide (nanoceria, nanoCeO2), are being investigated as the adjunctive therapy. CeO2 shows the activity of superoxide dismutase (SOD) and catalase mimetic activity, which are responsible for its antioxidant behavior. However, prolonged exposure to higher concentrations of nanoceria cells leads to the dysfunction of the antioxidant system, induction of intracellular oxidative stress and subsequent cytotoxicity in cells. The aim of this study was to investigate the cytotoxic effect of nanoparticles of CeO2 in colon cancer cells (HT-29) and the development of appropriate methods to monitor this effect. MTT test showed a lower cytotoxic activity than the standard cisplatin (concentrations used between 0-100 µM). EPR detection of total radicals using a spin probe TEMPONE and detection of OH radicals by fluorescence spectroscopy have shown that cellular mechanisms for the removal of free radicals are less efficient in cells treated with nanoceria, which explains the cytotoxicity of these nanoparticles on colon cancer cells.