The Effects of Triazine Herbicides on Critical Peroxide Metabolism Gene Expression in MCF-7 and MCF-10A Cells

Aim: To identify the oxidative stress impacts of chloro-s-triazine herbicides on human mammary epithelial cell lines.

Study Design: MCF-7 mammary epithelial carcinoma and MCF-10A mammary epithelial cells were treated with levels of three triazine herbicides in concentrations flanking the US FDA safe levels.

Place and Duration of Study: Department of Biology, Millikin University, in January 2015 through December 2015 and January 2019 through May 2020.

Methodology: We examined the oxidative effects of two triazine herbicides, atrazine and simazine, on estrogen-dependent MCF-7 mammary epithelial carcinoma cells using three different bioluminescent assay techniques. We then utilized real time PCR to analyze gene expression through RT-PCR analysis, in both MCF-7 cells and a non-cancerous cell line, MCF-10A, for both of these triazine herbicides plus the related cyanazine.

Results: At all concentrations of atrazine and simazine, no statistical differences were found in the levels of oxidized glutathione or total oxidized and reduced nicotinamide adenine dinucleotides phosphates. In stark contrast, levels of hydrogen peroxide were found to be statistically different from the control at all concentrations of atrazine and simazine tested. Using an Analysis of Variance (ANOVA) we determined that within the enzymatic portion of the hydrogen peroxide pathway there were statistically significant differences in the expression of Peroxiredoxin 1 (PRDX1), Sulfiredoxin (SRXN1), and Thioredoxin (TXN).

Conclusion: Exposure to triazines alters the hydrogen peroxide pathway, which in turn can greatly affect the stability of the cell milieu.