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Phytoestrogens modulate binding response of estrogen receptors alpha and beta to the estrogen response element.
J Agric Food Chem 2003; 51(26):7632-5JA

Abstract

Binding of estrogen receptor (ER) to estrogen response element (ERE) induces gene activation and is an important step in estrogen-induced biological effects. Here, we investigated the effects of some dietary phytoestrogens such as the isoflavones genistein and daidzein, its metabolite equol, and the coumestane coumestrol on the binding rate of ERalpha and ERbeta to ERE by a nonradioactive real-time method, the Biacore Technology. ERalpha and ERbeta were able to bind to ERE immobilized on the surface of a sensor chip even in the absence of estrogens. 17beta-Estradiol and phytoestrogens induced an increase in ER binding to ERE in a concentration-dependent manner. 17beta-Estradiol was a more potent activator of binding than the phytoestrogens studied. The concentrations of 17beta-estradiol inducing an increase in the binding response of ERalpha and ERbeta to ERE by 50% (EC(50)) as compared to unliganded ER were 0.03 and 0.01 microM, respectively. Regarding the efficacy of activation of ERalpha, from the most to the least effective compound, the sequence and the EC(50) were as follows: 17beta-estradiol (0.03 microM) > coumestrol (0.2 microM) > equol (3.5 microM) > genistein (15 microM) > daidzein (>300 microM) and for ERbeta 17beta-estradiol (0.01 microM) > coumestrol (0.025 microM) > genistein (0.03 microM) > daidzein (0.35 microM) > equol (0.4 microM). The ratios EC(50)alpha/EC(50)beta were calculated to be for 17beta-estradiol, 3; coumestrol, 8; equol, 8.8; genistein, 500; daidzein > 850. These ratios indicate that genistein and daidzein preferentially activate the binding of ERbeta to ERE. The endogenous hormone 17beta-estradiol as well as coumestrol and daidzein metabolite equol activate the binding of ERbeta to ERE only slightly more effectively than the binding of ERalpha to ERE. Thus, the effect of daidzein can be changed from a specific activator of ERbeta to an activator of both ER isotypes alpha and beta in humans who are able to convert daidzein to equol. While the results of the measurements with ERalpha were in line with the binding affinities of compounds tested for ER, there was a distinct difference between our results and the binding affinities of phytoestrogens for the ERbeta. This leads to the conclusion that phytoestrogens differ not only in their binding affinities for the ER, but also in their potential to increase the rate of receptor binding to the ERE.

Authors+Show Affiliations

Institute of Nutritional Physiology, Federal Research Centre for Nutrition, Karlsruhe, Germany.No affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

14664520

Citation

Kostelac, Drazen, et al. "Phytoestrogens Modulate Binding Response of Estrogen Receptors Alpha and Beta to the Estrogen Response Element." Journal of Agricultural and Food Chemistry, vol. 51, no. 26, 2003, pp. 7632-5.
Kostelac D, Rechkemmer G, Briviba K. Phytoestrogens modulate binding response of estrogen receptors alpha and beta to the estrogen response element. J Agric Food Chem. 2003;51(26):7632-5.
Kostelac, D., Rechkemmer, G., & Briviba, K. (2003). Phytoestrogens modulate binding response of estrogen receptors alpha and beta to the estrogen response element. Journal of Agricultural and Food Chemistry, 51(26), pp. 7632-5.
Kostelac D, Rechkemmer G, Briviba K. Phytoestrogens Modulate Binding Response of Estrogen Receptors Alpha and Beta to the Estrogen Response Element. J Agric Food Chem. 2003 Dec 17;51(26):7632-5. PubMed PMID: 14664520.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Phytoestrogens modulate binding response of estrogen receptors alpha and beta to the estrogen response element. AU - Kostelac,Drazen, AU - Rechkemmer,Gerhard, AU - Briviba,Karlis, PY - 2003/12/11/pubmed PY - 2004/1/22/medline PY - 2003/12/11/entrez SP - 7632 EP - 5 JF - Journal of agricultural and food chemistry JO - J. Agric. Food Chem. VL - 51 IS - 26 N2 - Binding of estrogen receptor (ER) to estrogen response element (ERE) induces gene activation and is an important step in estrogen-induced biological effects. Here, we investigated the effects of some dietary phytoestrogens such as the isoflavones genistein and daidzein, its metabolite equol, and the coumestane coumestrol on the binding rate of ERalpha and ERbeta to ERE by a nonradioactive real-time method, the Biacore Technology. ERalpha and ERbeta were able to bind to ERE immobilized on the surface of a sensor chip even in the absence of estrogens. 17beta-Estradiol and phytoestrogens induced an increase in ER binding to ERE in a concentration-dependent manner. 17beta-Estradiol was a more potent activator of binding than the phytoestrogens studied. The concentrations of 17beta-estradiol inducing an increase in the binding response of ERalpha and ERbeta to ERE by 50% (EC(50)) as compared to unliganded ER were 0.03 and 0.01 microM, respectively. Regarding the efficacy of activation of ERalpha, from the most to the least effective compound, the sequence and the EC(50) were as follows: 17beta-estradiol (0.03 microM) > coumestrol (0.2 microM) > equol (3.5 microM) > genistein (15 microM) > daidzein (>300 microM) and for ERbeta 17beta-estradiol (0.01 microM) > coumestrol (0.025 microM) > genistein (0.03 microM) > daidzein (0.35 microM) > equol (0.4 microM). The ratios EC(50)alpha/EC(50)beta were calculated to be for 17beta-estradiol, 3; coumestrol, 8; equol, 8.8; genistein, 500; daidzein > 850. These ratios indicate that genistein and daidzein preferentially activate the binding of ERbeta to ERE. The endogenous hormone 17beta-estradiol as well as coumestrol and daidzein metabolite equol activate the binding of ERbeta to ERE only slightly more effectively than the binding of ERalpha to ERE. Thus, the effect of daidzein can be changed from a specific activator of ERbeta to an activator of both ER isotypes alpha and beta in humans who are able to convert daidzein to equol. While the results of the measurements with ERalpha were in line with the binding affinities of compounds tested for ER, there was a distinct difference between our results and the binding affinities of phytoestrogens for the ERbeta. This leads to the conclusion that phytoestrogens differ not only in their binding affinities for the ER, but also in their potential to increase the rate of receptor binding to the ERE. SN - 0021-8561 UR - https://www.unboundmedicine.com/medline/citation/14664520/Phytoestrogens_modulate_binding_response_of_estrogen_receptors_alpha_and_beta_to_the_estrogen_response_element_ L2 - https://dx.doi.org/10.1021/jf034427b DB - PRIME DP - Unbound Medicine ER -