Doxorubicin-Loaded Cerium Oxide Nanoparticles Suppress Cell Proliferation, Migration and Invasion of Triple-Negative Breast Cancer Cells.

Cerium oxide nanoparticles (Ceria NPs), possessing redox activity, exhibit selective anticancer effects and hold significant promise for cancer therapy. In this study, Ceria NPs were synthesized via a hydrothermal method and characterized for stability in a biological environment. Optimal colloidal dispersion was achieved in 10% fetal bovine serum (FBS) with a hydrodynamic diameter of 56.3 nm. Ceria NPs exhibited strong antioxidant activity tested by DPPH assay and showed high biocompatibility, displaying minimal toxicity toward normal breast epithelial cells (MCF-10A) while exerting cytotoxic effects on breast cancer cells (IC50 = 363.0 ± 71.89 μg mL-1 for MCF-7 and 547.9 ± 0.14 μg mL-1 for MDA-MB-231). Given their limited standalone cytotoxicity but favorable selectivity, Ceria NPs were employed as a nanocarrier for doxorubicin (Dox) to enhance anticancer efficacy while potentially reducing systemic side effects. Ceria-Dox markedly enhanced cytotoxic efficacy, reducing IC50 values to 129.3 ± 21.86 μg mL-1 in MCF-7 and 33.2 ± 1.37 μg mL-1 in MDA-MB-231 cells, with more pronounced effects in TNBC cells while maintaining low toxicity toward normal cells. Live/dead staining confirmed a dose-dependent cytotoxicity, while the transwell assay demonstrated strong inhibition of migration and invasion in TNBC cells treated with Ceria-Dox. These findings highlight Ceria-Dox as a colloidally stable nanoplatform that delivers dual therapeutic actions, including potent cytotoxicity and suppression of metastatic potential, underscoring its promise for treating breast cancer, particularly aggressive subtypes such as triple-negative breast cancer.