Publication details
Aryl Hydrocarbon Receptor-Dependent Metabolism Plays a Significant Role in Estrogen-Like Effects of Polycyclic Aromatic Hydrocarbons on Cell Proliferation
| Authors | |
|---|---|
| Year of publication | 2018 |
| Type | Article in Periodical |
| Magazine / Source | Toxicological sciences |
| MU Faculty or unit | |
| Citation | |
| Web | http://dx.doi.org/10.1093/toxsci/kfy153 |
| Doi | http://dx.doi.org/10.1093/toxsci/kfy153 |
| Keywords | aryl hydrocarbon receptor; polycyclic aromatic hydrocarbons; cytochrome P450 family 1; hydroxylated metabolites; estrogen receptor; cell cycle |
| Description | Polycyclic aromatic hydrocarbons (PAHs) are widespread environmental contaminants that interact in a complex manner with both the aryl hydrocarbon receptor (AhR) and estrogen receptors (ER). Their potential endocrine-disrupting activities may depend on both inhibitory AhR-ER cross-talk and on AhR-dependent metabolic production of estrogenic PAH metabolites. Here, we analyzed the impact of AhR on estrogen-like effects of PAHs, such as benzotalpyrene (BaP), in particular, on control of cell cycle progression/cell proliferation. Using AhR knockout variant of estrogen-sensitive human breast cancer MCF-7 cells (MCF-7 AhR(KO) cells), we observed that the AhR-dependent control of cytochrome P450 family 1 (CYP1) expression played a major role in formation of estrogenic BaP metabolites, most notably 3-OH-BaP, which contributed to the ER-dependent induction of cell cycle progression/cell proliferation. Both BaP metabolism and the BaP-induced S-phase transition/cell proliferation were inhibited in MCF-7 AhR(KO) cells, whereas these cells remained sensitive towards both endogenous estrogen 17 beta-estradiol or hydroxylated BaP metabolites. BaP was found to increase the activity of ER-dependent luciferase reporter gene in wild-type MCF-7 cells; however, unlike its hydroxylated metabolite, BaP failed to stimulate luciferase activity in MCF-7 AhR(KO) cells. Similarly, estrogen-like effects of other known estrogenic PAHs, such as benzfajanthracene or 3-methylcholanthrene, were diminished in MCF-7 AhR(KO) cells. Ectopic expression of human CYP1A1 and CYP1B1 enzymes partly restored both BaP metabolism and its effects on cell proliferation. Taken together, our data suggest that the AhR-dependent metabolism of PAHs contributes significantly to the impact of PAHs on cell proliferation in estrogen-sensitive cells. |