The Anti-Breast Cancer Effects of Green-Synthesized Zinc Oxide Nanoparticles Using Carob Extracts

Background: The use of nanoparticles synthesized by the green method to treat cancer is fairly recent. The aim of this study was to evaluate cytotoxicity, apoptotic and anti-angiogenic effects and the expression of involved genes, of Zinc Oxide Nanoparticles (ZnO-NPs) synthesized with Carob extracts on different human breast cancer cell lines. Methods: ZnO-NPs were synthesized using the extracts of Carob and characterized with various analytical techniques. The MCF-7 and MDA-MB231 cells were treated at different times and concentrations of ZnO-NPs. The cytotoxicity, apoptosis, and anti-angiogenic effects were examined using a series of cellular assays. Expression of apoptotic genes (Bax and Bcl2) and anti-angiogenic genes, Vascular Endothelial Growth Factor (VEGF) and its Receptor (VEGF-R) in cancer cells treated with ZnO-NPs were examined with Reverse Transcriptionquantitative Polymerase Chain Reaction (RT-qPCR). The anti-oxidant activities of ZnO-NPs were evaluated by ABTS and DPPH assay. Results: Exposure of cells to ZnO-NPs resulted in a dose-dependent loss of cell viability. The IC50 values at 24, 48, and 72 hours were 125, 62.5, and 31.2μg/ml, respectively (p<0.001). ZnO-NPs treated cells showed, in fluorescent microscopy, that ZnO-NPs are able to upregulate apoptosis and RT-qPCR revealed the upregulation of Bax (p<0.001) and downregulation of Bcl-2 (p<0.05). ZnO-NPs increased VEGF gene expression while decreasing VEGF-R (p<0.001). The anti-oxidant effects of ZnO-NPs were higher than the control group and were dose-dependent (p<0.001). Conclusion: ZnO-NPs synthetized using Carob extract have the ability to eliminate breast cancer cells and inhibit angiogenesis, therefore, they could be used as an anticancer agent.