Antifungal climbazole alters androgenic pathways in mammalian cells

Among antifungal agents used in pharmaceuticals and personal care products, the synthetic azole climbazole (CBZ; 1-(4-Chlorophenoxy)-1-(imidazol-1-yl)-3,3-dimethylbutan-2-one) acts on the fungus Malassezia. Despite concerns surrounding its effects on health, based on alterations to reproduction and steroidogenesis found in fish, little is known about its mechanism of action as an endocrine disrupting chemical (EDC) in mammalian cells. In this study, using OECD test guidelines, we investigated the effects of CBZ (i) in H295R cells, on the production of estradiol and testosterone, as well as intermediate metabolites in steroidogenesis pathway, and (ii) in HeLa9903 and AR-EcoScreen cell lines, on the transactivation of estrogen and androgen receptors. Our results are the first evidence in H295R cells, that CBZ treatment (from 0.3 μM) decreased secreted levels of testosterone and estradiol. This was associated with reduced 17α-hydroxypregnenolone and 17α-hydroxyprogesterone levels. The altered levels of these metabolites were associated with a decrease in cytochrome P450 17α-hydroxylase/17,20-lyase (Cyp17A1) activity without any effect on its protein level. CBZ was also found to exert antagonistic effects toward androgen and estrogen α receptors. These results give insights into the toxicological mechanism of action of CBZ. Many azoles share structural similarities; therefore, caution should be adopted due to their potential toxicity.