Emerging organophosphate ester resorcinol bis(diphenyl phosphate) exerts estrogenic effects via estrogen receptor pathways

Yue Xie; Qi Zhang; Lu Chen; Fangfang Li; Minjie Li; Liang-Hong Guo

doi:10.1016/j.tox.2023.153649

Emerging organophosphate ester resorcinol bis(diphenyl phosphate) exerts estrogenic effects via estrogen receptor pathways

Toxicology. 2023 Nov:499:153649. doi: 10.1016/j.tox.2023.153649. Epub 2023 Oct 11.

Authors

Yue Xie¹, Qi Zhang², Lu Chen¹, Fangfang Li², Minjie Li³, Liang-Hong Guo⁴

Affiliations

¹ College of Life Sciences, China Jiliang University, 258 Xueyuan Street, Hangzhou, Zhejiang 310018, China; Institute of Environmental and Health Sciences, China Jiliang University, 168 Xueyuan Street, Hangzhou, Zhejiang 310018, China.
² Institute of Environmental and Health Sciences, China Jiliang University, 168 Xueyuan Street, Hangzhou, Zhejiang 310018, China; College of Quality and Safety Engineering, China Jiliang University, 258 Xueyuan Street, Hangzhou, Zhejiang 310018, China.
³ Institute of Environmental and Health Sciences, China Jiliang University, 168 Xueyuan Street, Hangzhou, Zhejiang 310018, China; College of Quality and Safety Engineering, China Jiliang University, 258 Xueyuan Street, Hangzhou, Zhejiang 310018, China. Electronic address: mjli@cjlu.edu.cn.
⁴ Institute of Environmental and Health Sciences, China Jiliang University, 168 Xueyuan Street, Hangzhou, Zhejiang 310018, China; College of Quality and Safety Engineering, China Jiliang University, 258 Xueyuan Street, Hangzhou, Zhejiang 310018, China. Electronic address: lhguo@cjlu.edu.cn.

PMID: 37827210
DOI: 10.1016/j.tox.2023.153649

Abstract

Environmental occurrence and human exposure of emerging organophosphate esters (eOPEs) have increased significantly in recent years. Resorcinol bis(diphenyl) phosphate (RDP) is one of the major eOPEs detected in indoor dust, but the knowledge on its toxicities and health risks is rather limited. In this study, we investigated the in vitro estrogenic effects and underlying mechanism of RDP in comparison with a legacy OPE triphenyl phosphate (TPHP). Our results showed that RDP promoted MCF-7 cell proliferation with the lowest effect concentration of 2.5 μM, and the maximum enhancement of 1.6 folds is greater than that of TPHP (1.3 folds). The effect was inhibited completely by an estrogen receptor (ER) antagonist, suggesting that ER activation was responsible for the enhancement. In luciferase reporter gene assays both RDP and TPHP activated ER transcriptional activity at 2.5 μM, but RDP activity was higher than TPHP. Competitive fluorescence binding assays showed that RDP bound to ER with an IC₁₀ of 0.26 μM, which is 20 folds lower than TPHP (5.6 μM). Molecular docking simulation revealed that both RDP and TPHP interacted with ER at the binding pocket of estradiol, although the hydrogen bonds were different. Taken together, RDP exerted stronger estrogenic effects than TPHP through ER-mediated pathways and may pose more health risks.

Keywords: Cell proliferation; Health risk assessment; Molecular docking; Receptor binding assay; Reporter gene assay.

MeSH terms

Esters / toxicity
Estrogens / toxicity
Flame Retardants*
Humans
Molecular Docking Simulation
Organophosphates / toxicity
Phosphates*
Receptors, Estrogen
Resorcinols / toxicity

Substances

Phosphates
Receptors, Estrogen
diphenyl
Estrogens
triphenyl phosphate
Organophosphates
resorcinol
Resorcinols
Esters
Flame Retardants