Inverse antagonist activities of parabens on human oestrogen-related receptor γ (ERRγ): in vitro and in silico studies.

Abstract

Parabens are p-hydroxybenzoic acid esters that have been used extensively as preservatives in foods, cosmetics, drugs and toiletries. These intact esters are commonly detected in human breast cancer tissues and other human samples, thus arousing concern about the involvement of parabens in human breast cancer. In this study, an in vitro nuclear receptor coactivator recruiting assay was developed and used to evaluate the binding activities of parabens, salicylates and benzoates via antagonist competitive binding on the human oestrogen-related receptor γ (ERRγ), which is known as both a diagnostic biomarker and a treatment target of breast cancer. The results showed that all of the test parabens (methyl-, ethyl-, propyl-, butyl- and benzylparaben) possessed clear inverse antagonist activities on ERRγ, with a lowest observed effect level (LOEL) of 10(-7)M and the 50% relative effective concentrations (REC50) varying from 3.09×10(-7) to 5.88×10(-7)M, whereas the salicylates possessed much lower activities and the benzoates showed no obvious activity. In silico molecular docking analyses showed that parabens fitted well into the active site of ERRγ, with hydrogen bonds forming between the p-hydroxyl group of parabens and the Glu275/Arg316 of ERRγ. As the paraben levels reported in breast cancer tissues are commonly higher than the LOELs observed in this study, parabens may play some role via ERRγ in the carcinogenesis of human breast cancer. In addition, parabens may have significant effects on breast cancer patients who are taking tamoxifen, as ERRγ is regarded as a treatment target for tamoxifen.

• Authors: Zhaobin Zhang, Libei Sun, Ying Hu, Jian Jiao, Jianying Hu
• Journal: Toxicology and applied pharmacology (Toxicol Appl Pharmacol) Vol. 270 Issue 1 Pg. 16-22 (Jul 01 2013) ISSN: 1096-0333 [Electronic] United States
• PMID: 23583298 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2013 Elsevier Inc. All rights reserved.

Chemical References

• Parabens
• Receptors, Estrogen
• estrogen receptor gamma

Topics

• Computer Simulation
• Dose-Response Relationship, Drug
• Humans
• Parabens (metabolism, toxicity)
• Protein Binding (physiology)
• Protein Structure, Secondary
• Receptors, Estrogen (antagonists & inhibitors, chemistry, metabolism)