Abstract
Background: Colorectal cancer (CRC) is one of the most common gastrointestinal cancers worldwide. It is the second leading cause of death in women after breast cancer. Objectives: The present study aimed to determine the cytotoxic effects of zinc oxide (ZnO) nanoparticles on colon cancer (SW480) viability and nitric oxide (NO) level in vitro. Methods: In this experimental study, the values of 15.62, 31.25, 62.5, 125, 250, and 500 μg/mL of ZnO nanoparticles were considered to treat SW480 cells for 24 hours. The MTT method was used to determine cell viability. The amount of NO was also measured using the grease method. An analysis of variance (ANOVA) was used to analyze the data. Results: Treatment of SW480 cells with ZnO nanoparticles resulted in decreased viability in a dose-dependent pattern. NO concentration significantly increased in response to an effective dose of ZnO nanoparticles (108 µg/mL) compared to the control group (P < 0.001). Conclusions: ZnO nanoparticles have cytotoxic effects on colon cancer cells. The cytotoxic effect of ZnO nanoparticles on colon cancer cells is partly mediated by NO in cancer cells.