Anti-thyroid hormone activity of bisphenol A, tetrabromobisphenol A and tetrachlorobisphenol A in an improved reporter gene assay.
Previously, we transiently transfected Gal4-fused thyroid hormone receptor (TR) expressing vector and the Gal4 response reporter structure pUAS-tk-luc into HepG2 cell, developed a TR beta-1 mediated reporter gene assay to screen for compounds that acted on the TR signaling pathway. In this study, we improved the test efficiency by changing the transfected cell line into CV-1 cell. Triiodothyronine (T3) and thyroxine (T4) induced higher luciferase expression, with the median effective concentration (EC(50)) of 1.16 x 10(-8) and 1.36 x 10(-7)M, respectively. Bisphenol A (BPA) was selected as a positive antagonist, exhibiting weak anti-thyroid hormone activity with the median inhibitory concentration (IC(50)) of 1.64 x 10(-5)M. The assay showed acceptable repeatability to T3 with inter coefficient of variability (CV) of 27.5% and intra CV of 18.6%. Two flame retardants, tetrabromobisphenol A (TBBPA) and tetrachlorobisphenol A (TCBPA), were tested for their agonist and antagonist activities. As a result, we found that both of them possessed TR antagonist activity and neither of them showed agonist activity. These results suggested that TBBPA and TCBPA could act as TH antagonists. This assay provided a useful tool for the assessment of environmental chemicals as thyroid system disruptors.
Sun
Hong
H
Jiangsu Provincial Center for Disease Prevention and Control, Nanjing 210009, China.
Shen
Ou-Xi
OX
Wang
Xin-Ru
XR
Zhou
Lian
L
Zhen
Shi-Qi
SQ
Chen
Xiao-Dong
XD
D000818:Animals; D001559:Benzhydryl Compounds; D002460:Cell Line; D002522:Chlorocebus aethiops; D002733:Chlorophenols / Q000008:administration & dosage / Q000633:toxicity*; D005411:Flame Retardants / Q000008:administration & dosage / Q000633:toxicity; D005786:Gene Expression Regulation / Q000187:drug effects; D017930:Genes, Reporter; D020128:Inhibitory Concentration 50; D007668:Kidney / Q000187:drug effects / Q000378:metabolism; D008156:Luciferases / Q000235:genetics; D010636:Phenols / Q000008:administration & dosage / Q000633:toxicity*; D011075:Polybrominated Biphenyls / Q000008:administration & dosage / Q000633:toxicity*; D011988:Receptors, Thyroid Hormone / Q000187:drug effects* / Q000378:metabolism; D015203:Reproducibility of Results; D013974:Thyroxine / Q000378:metabolism; D014284:Triiodothyronine / Q000378:metabolism; D000098826:Bisphenol A Compounds
D001559:Benzhydryl Compounds; D002733:Chlorophenols; D005411:Flame Retardants; D008156:Luciferases; D010636:Phenols; D011075:Polybrominated Biphenyls; D011988:Receptors, Thyroid Hormone; D013974:Thyroxine; D014284:Triiodothyronine; C041181:tetrachlorodian; C020806:tetrabromobisphenol A; C006780:bisphenol A; D000098826:Bisphenol A Compounds