Title: Application of in vitro and in vivo reporter gene assays for assessing (mixtures of ) estrogenic substances

Auteur(s): Legler J ; Lanser PH ; Brouwer A ; Vethaak D ; De Voogt P ; Murk AJ ; Van der Burg B ;  ; 

Year: 2001

Journal: Organohalogen Compounds

Subject(s): Reporter gene ; estrogen ; Luciferase ; gene expression ; ER CALUX ; CALUX ; Estrogenic potency ; Reporter gene assay ;  ; 

Summary: Two new assays to assess estrogenic activity have been recently developed in our laboratories: the in vitro Estrogen Receptor-mediated Chemical Activated LUciferase gene eXpression (ER CALUX) assay using human T47D breast cancer cells, and the in vivo transgenic zebrafish assay. In both assays, an ER-mediated luciferase reporter gene construct containing 3 estrogen response elements (ERE) has been stably introduced and integrated in the genome of the T47D cells and transgenic zebrafish. In both assays, the luciferase reporter gene is induced following binding of compounds to endogenous ERs and activation of the receptor, and consequently, binding of the ligand-receptor complex to EREs present in the promoter region of the luciferase gene. Using the transgenic zebrafish assay in which compounds are exposed via the water phase, the environmental chemistry, bioavailability and toxicokinetics of the test substance in vivo are taken into account. The aim of this study was to compare the reporter gene induction in the ER-CALUX and the transgenic zebrafish assays following exposure to environmentally relevant (xeno-)estrogens. The in vitro and in vivo estrogenic potency of mixtures of (xeno-)estrogens in a domestic wastewater treatment plant (WTP) effluent was tested to determine if the reporter gene assays could be applied to environmental mixtures.