Medical ozone induces proliferation and migration inhibition through ROS accumulation and PI3K/AKT/NF-κB suppression in human liver cancer cells in vitro

Hepatocellular carcinoma is one of the most common malignancies and leading cancer-associated deaths worldwide. Ozone has been proposed as a promising therapeutic agent in the treatment of various disorders. The purpose of this paper is to assess the potential anticancer effects of the ozone on liver cancer cells. The liver cancer cell line of bel7402 and SMMC7721 was used in this study. Proliferation was evaluated using the CCK-8 and the colony formation assay. Wond healing assay and transwell assay without Matrigel were used to evaluate their migration ability. Flow cytometry was used for cell cycle analysis and reactive oxygen species (ROS) determination. Glutathione detection kit was used for measurement of glutathione level. Protein expression was estimated by western blot analysis. Ozone treatment inhibited liver cancer cell proliferation, colony formation. Ozone induced G2/M phase cell cycle arrest, which could be elucidated by the change of protein levels of p53, p21, Cyclin D1, cyclin B1, cdc2, and CDK4. We also found that ozone treatment inhibited migration ability by inhibiting EMT-relating protein. Ozone also induced ROS accumulation and decreased glutathione level decreased, which contributed to the inactivation of the PI3K/AKT/NF-κB pathway. Finally, we found that pre-treatment of liver cancer cells with N-acetylcysteine resisted ozone-induced effects. Ozone restrains the proliferation and migration potential and EMT process of liver cancer cells via ROS accumulation and PI3K/AKT/NF-κB suppression.