Atrazine Promoted Epithelial Ovarian Cancer Cells Proliferation and Metastasis by Inducing Low Dose Reactive Oxygen Species (ROS)

Atrazine (ATZ) is a triazine herbicide that is widely used in agriculture and has been detected in surface and underground water. Recently, laboratory and epidemiological research have found that the bioaccumulation of ATZ in the environment leads to biotoxicity in the human immune and endocrine systems and results in tumor development. To investigate the effects of ATZ exposure on epithelial ovarian cancer (EOC) cells and elucidate the potential mechanisms governing these effects. The human EOC cell lines Skov3 and A2780 were used in this study to explore the effects and mechanisms of ATZ exposure on EOC. The mouse embryonic osteoblastic precursor MC3T3-E1 cells served as the control cells to determine the effects of ATZ on cancer cell lines. After exposure to ATZ, the MTT assay, flow cytometry, the colony formation assay, immunohistochemical staining, the cell scratch assay, and the Transwell assay were used to evaluate the proliferative activity, invasion, and migration capabilities of EOC cell lines. Moreover, flow cytometry was also applied to detect the level of reactive oxygen species (ROS) in these two EOC cell lines, as well as the MC3T3-E1 cells. To further illustrate the underlying mechanisms governing the effect of ATZ on EOC, real-time PCR and Western blotting were employed to assess the transcription and the expression level of Stat3 signaling pathway-related genes in Skov3 and MC3T3-E1 cells. The results showed that following ATZ treatment, the cell proliferation, migration, and invasion potencies of Skov3 and A2780 cells were increased compared to those of the control group. Meanwhile, the ROS levels of EOC and MC3T3-E1 cells were notably elevated after ATZ treatment. In Skov3 cells, the expression levels of p53 and p21 were downregulated, while those of Cyclin E, vascular endothelial growth factor (VEGF), matrix metallopeptidase 2 (MMP2), MMP9, signal transducers and activators of transcription 3 (Stat3), and p-Stat3 were upregulated by ATZ treatment. In MC3T3-E1 cells, however, ATZ treatment did not affect the level of p53/p21 mRNA compared to the control groups. Moreover, there was no significant change in the expression levels of Stat3 and p-Stat3 in MC3T3-E1 cells exposed to ATZ. This phenomenon was observed while the proliferation rate was enhanced in MC3T3-E1 cells by ATZ. The results of this study suggest that ATZ effectively promotes the proliferation and metastasis of EOC cells through the Stat3 signaling pathway by inducing low levels of ROS. Additionally, although ATZ might also induce proliferative potential in normal cells, the mechanisms governing its effects in these cells might be different from those in EOC cells.