In Vitro Effects of Herbicides and Insecticides on Human Breast Cells

Abstract

Numerous studies have indicated that the pesticides and herbicides used in agricultural processes in the United States and Europe may have detrimental effects upon human health. Many of these compounds have been indicated as potential endocrine and reproductive disruptors, although the studies have examined supraphysiological levels well above the US EPA safe levels for drinking water and have often examined these effects in “model” cell lines such as Chinese hamster ovary cells. We have now examined the cytotoxicity of more environmentally relevant concentrations of four herbicides, acetochlor, atrazine, cyanazine, and simazine, and two insecticides, chlorpyrifos and resmethrin, in three human breast cell lines. Interestingly, cytotoxicity was not observed in the estrogen-dependent MCF-7 mammary epithelial carcinoma cells; rather increases in cell viability were seen for some of the compounds at select concentrations. These results vary greatly from what was observed in the estrogen independent MDA-MB-231 breast cancer cells and the non-cancerous MCF-10A breast cells. This gives insight into how different tumors may respond to pesticide exposure and allows us to make more accurate conclusions about the potential cytotoxicity or, at times, stimulatory actions of these pesticides.

Differences in GPR30 Regulation by Chlorotriazine Herbicides in Human Breast Cells

“…The lack of difference between treated cell growth in MCF-7 cells kept in a reduced medium (hormone-free and lacking phenol red) and our maintenance medium (containing serum and phenol red) indicates that the assays being performed are not dependent upon any estrogenicity of the triazines ( Figure 1 ). This is in agreement with our previous work which examined the viability of MCF-7 and MDA-MB-231 cells after treatment with four herbicides at levels just above those deemed safe for daily consumption by the US EPA [ 18 ]. Our current study examines levels that overlap this work, yet it looks at a shorter treatment time (twenty-four instead of forty-eight hours).…”

“…Although the levels of triazine class herbicides used in this and our previous work did not alter cell growth, nor did it affect cellular migration [ 18 , 40 ], we wanted to determine if genomic changes in GPR30 occurred with chlorotriazine exposure. In fact, upon examining the expression level of GPR30, the proposed receptor for these compounds, we did observe discrete differences in expression dependent upon cell milieu.…”

“…The ability of atrazine in particular to cause a change in gene regulation is also consistent with the previously observed ability of xenoestrogens, especially chlorotriazines [ 24 , 50 ], although the roles of cyanazine and simazine have been less well studied than atrazine. Our previous studies did not indicate changes in growth rates when we utilized atrazine, cyanazine, and simazine at levels that far exceeded the EPA safe level in drinking water [ 18 ]. Likewise, when assessing the ability to respond after artificial wound induction, MCF-7 cells showed no change from the DMSO control when exposed to triazines, with less than 40% regrowth over 72 hours [ 40 ]; this was in contrast to the effects of estradiol which stimulated regrowth and migration.…”

Organophosphate Pesticide Exposure and Breast Cancer Risk: A Rapid Review of Human, Animal, and Cell-Based Studies

“…However, another concluded that malathion did not display any estrogenic activity [ 43 ]. Three studies demonstrated the estrogenic potential of chlorpyrifos by binding to sex hormones [ 44 ] and acting as estrogen agonists [ 45 , 46 ]. However, two other studies did not find any chlorpyrifos-induced endocrine disrupting potential [ 47 , 48 ].…”

Dopaminergic Dysfunction in Mammalian Dopamine Neurons Induced by Simazine Neurotoxicity

“…The huge amounts applied and the diverse exposure routes of simazine have increased the risk to human health. Moreover, simazine is considered to be slightly soluble and nontoxic, is difficult to degrade in the natural environment, and has multiple exposure pathways, including water, soil, and the food chain [ 7 , 8 , 9 , 10 ]. Simazine has already been detected at high concentrations in rainwater, surface water and underground water in France, the US and Spain, and has even been detected in food such as tomatoes and living fish [ 11 , 12 , 13 ].…”