Combined action of estrogen receptor agonists and antagonists in two-hybrid recombinant yeast in vitro

Abstract

a b s t r a c tEstrogen receptor (ER) antagonistic chemicals in aquatic environments are believed to influence the binding of both endogenous and exogenous estrogens to ERs in aquatic organisms. Although the combined effects of estrogenic compounds have attracted much scientific concern, little work has been done on the influence of such antiestrogens on the biological effects of estrogens. This study focused on how the presence of different amounts of antagonists affects the results of ER agonist activity tests. To achieve this, three questions were stated and answered in sequence. A two-hybrid recombinant yeast assay mediated by ER was adopted, providing a single mode of action and single target of action for this study. Mixtures created by an ER agonist and three antagonists following the fixed-ratio principle were assessed. The concentration of 17β-estradiol causing maximum induction was set as the fixed dose of estrogen in the antagonist activity test (question 1). When the two classes of chemicals coexisted, antiestrogens, which as a whole behaved according to the concentration addition model (question 2), decreased the response of estrogen and compressed the concentration-response curves along the y-axis in the agonist activity test (question 3). This may cause the estradiol equivalent to be underestimated and potentially mask the action of estrogenic effects in toxicity evaluation of environmental samples.

Integrated Studies on Male Reproductive Toxicity of Bis(2-ethylhexyl)-tetrabromophthalate: in Silico, in Vitro, ex Vivo, and in Vivo

“…The recombinant AR two-hybrid yeast cells were incubated overnight and taken inoculated into SD/-Trp /-Leu culture (1: 10, v:v) to obtain an OD 600 value of 0.75 as previously reported . Then, 200 μL of bacterial suspension containing 0, 0.0625, 0.125, 0.25, 0.5, and 1 μM (equal to 0, 44.13, 88.27, 176.54, 353.07, 706.14 μg/L) TBPH with or without dihydrotestosterone (DHT, 50 nM) was transferred to a 96-well plate and incubated at 37 °C for 2 h. The exposure concentrations of TBPH were determined based on the results of the pre-experiment, and the concentration of DHT was selected according to previous studies. , The contents of DMSO in control, DHT, and TBPH treatments were lower than 0.1% (v/v). Each treatment had three replicate wells ( n = 3).…”

Effect-Targeted Mapping of Potential Estrogenic Agonists and Antagonists in Wastewater via a Conformation-Specific Reporter-Mediated Biosensor

“…According to our knowledge, in most cases, the comprehensive estrogenic effect in wastewater samples worldwide generally exhibits estrogenic agonist activities, usually characterized by E 2 -effect equivalent (E 2 -EE) because the antagonist activities are very weak compared to the agonist activities. In theory, the E 2 -EE measured by yeast two-hybrid bioassay is positively correlated with the difference value [(E 2 -BAE) – F ·(4-OHT-BAE)] between the agonist binding activity equivalent and the antagonist binding activity equivalent measured by the developed biosensor, where F represents the E 2 -equivalence factors of 4-OHT, which is as low as approximately 7.3 × 10 –4 . , Therefore, it can be inferred that in most cases, the E 2 -EE can be proportional to the E 2 -BAE due to the 4 orders of magnitude difference in F . Indeed, it could be observed that the E 2 -EE of the above two WWTPs measured by yeast two-hybrid bioassay exhibited a strong linear relationship ( r 2 = 0.991, p < 0.0001) with the E 2 -BAE measured by the developed biosensor (Figure c).…”

“…In theory, the E 2 -EE measured by yeast two-hybrid bioassay is positively correlated with the difference value [(E 2 -BAE) − F•(4-OHT-BAE)] between the agonist binding activity equivalent and the antagonist binding activity equivalent measured by the developed biosensor, where F represents the E 2 -equivalence factors of 4-OHT, which is as low as approximately 7.3 × 10 −4 . 38,39 Therefore, it can be inferred that in most cases, the E 2 -EE can be proportional to the E 2 -BAE due to the 4 orders of magnitude difference in F. Indeed, it could be observed that the E 2 -EE of the above two WWTPs measured by yeast two-hybrid bioassay exhibited a strong linear relationship (r 2 = 0.991, p < 0.0001) with the E 2 -BAE measured by the developed biosensor (Figure 4c). Therefore, it was expected that the results of the developed biosensor would be comparable to those of the traditional yeast two-hybrid bioassay in the vast majority of wastewater samples.…”

Elucidation of Agonist and Antagonist Dynamic Binding Patterns in ER-α by Integration of Molecular Docking, Molecular Dynamics Simulations and Quantum Mechanical Calculations

“…Those structures are useful to understand the structural changes due to agonist and antagonist binding in the ERα LBP. Various computational techniques such as molecular docking [18][19][20][21][22][23][24], MD simulations [25][26][27][28][29][30], predictive modeling [31][32][33][34][35][36][37][38][39][40][41], and in vitro studies were conducted to predict ER binders or non-binders [42,43] and agonists or antagonists [44,45].…”