Mahnaz Tourani - Department Of Biology, Mashhad Branch, Islamic Azad University, Mashhad, Iran
Ali Neamati - Department Of Biology, Mashhad Branch, Islamic Azad Univesity, Mashhad, Iran
Masoud Homayouni - Department Of Biology, Mashhad Branch, Islamic Azad University, Mashhad, Iran

Cerium oxide nanoparticles (CeO2-NPs) have received much attention in nanotechnology due to their useful applications as antioxidants in biological systems, catalysts and fuel cells. The antioxidantcapacity of the substance is an important factor in the evaluation of therapeutic applications, which is especially important in the treatment of diseases, including cancer. The purpose of this study was toexamine the cytotoxic effects of CeO2-NPs biosynthesized by Hyssopus officinalis water extract (CeO2-NPs/Hf) on MCF-7 breast cancer cells. MCF-7 cancer cell lines were cultured, seeded and thentreated with different concentrations (0, 62.5, 125, 250 and 500 μg/ml) of CeO2-NPs/Hf for three times 24, 48 and 72h. The viability of the cancerous cells and inhibitory concentration (IC50) wereestimated by the methylthiazol tetrazolium (MTT) procedure. The absorbance was measured at wavelengths of 570nm. The results of the MTT assay showed that CeO2-NPs/Hf declined the proliferation of MCF-7 cells in dose- and time-dependently. The IC50 during the incubation times of 24 , 48 and 72h were determined 500, 200 and 125 μg/mL, respectively (P<0.05). Survival rates decreased from 70% to 37% 48 h after exposure with 62.5 and 500 μg/mlconcentrations of CeO2- NPs/Hf. Green cerium oxide nanoparticles biosynthesized by Hyssopus officinalis water extract have cytotoxic effects in MCF-7 breast cancer cells so CeO2-NPs/Hf can be considered as a valuable source of unknown therapeutic agents against breast cancer.

Breast Cancer, Cancer Prevention, Cell and Cancer, Multidisciplinary Cancer Research,Cancer Treatment and Management