Air, water, soil and environmental signaling.

Within a remarkably short timespan the world population doubled and transitioned from an agrarian to an urban-industrial society. The transition was accompanied by the major expansion of industries that releases enormous amounts of toxicants into the air, water, and soil. Naturally occurring and synthetic chemicals compounds utilized the same signaling system as vertebrate internal cell signaling systems. The concept of environmental signals provides insights to address the impact of biochemically active toxicants on humans and the ecosystems that they share with other species. Disruption of the broad signaling systems has the potential for global change that transcends the biological systems of all organisms, including humans.

Minireview: Endocrine Disruptors: Past Lessons and Future Directions.

Within the past few decades, the concept of endocrine-disrupting chemicals (EDCs) has risen from a position of total obscurity to become a focus of dialogue, debate, and concern among scientists, physicians, regulators, and the public. The emergence and development of this field of study has not always followed a smooth path, and researchers continue to wrestle with questions about the low-dose effects and nonmonotonic dose responses seen with EDCs, their biological mechanisms of action, the true pervasiveness of these chemicals in our environment and in our bodies, and the extent of their effects on human and wildlife health. This review chronicles the development of the unique, multidisciplinary field of endocrine disruption, highlighting what we have learned about the threat of EDCs and lessons that could be relevant to other fields. It also offers perspectives on the future of the field and opportunities to better protect human health.

The Effects of Endocrine Disruptors on Adipogenesis and Osteogenesis in Mesenchymal Stem Cells: A Review.

Endocrine-disrupting chemicals (EDCs) are prevalent in the environment, and epidemiologic studies have suggested that human exposure is linked to chronic diseases, such as obesity and diabetes. In vitro experiments have further demonstrated that EDCs promote changes in mesenchymal stem cells (MSCs), leading to increases in adipogenic differentiation, decreases in osteogenic differentiation, activation of pro-inflammatory cytokines, increases in oxidative stress, and epigenetic changes. Studies have also shown alteration in trophic factor production, differentiation ability, and immunomodulatory capacity of MSCs, which have significant implications to the current studies exploring MSCs for tissue engineering and regenerative medicine applications and the treatment of inflammatory conditions. Thus, the consideration of the effects of EDCs on MSCs is vital when determining potential therapeutic uses of MSCs, as increased exposure to EDCs may cause MSCs to be less effective therapeutically. This review focuses on the adipogenic and osteogenic differentiation effects of EDCs as these are most relevant to the therapeutic uses of MSCs in tissue engineering, regenerative medicine, and inflammatory conditions. This review will highlight the effects of EDCs, including organophosphates, plasticizers, industrial surfactants, coolants, and lubricants, on MSC biology.

Glyceollin, a novel regulator of mTOR/p70S6 in estrogen receptor positive breast cancer.

An estimated 70% of breast cancer tumors utilize estrogen receptor (ER) signaling to maintain tumorigenesis and targeting of the estrogen receptor is a common method of treatment for these tumor types. However, ER-positive (+) breast cancers often acquire drug resistant or altered ER activity in response to anti-estrogens. Here we demonstrate glyceollin, an activated soy compound, has anti-estrogen effects in breast cancers. We demonstrate through estrogen response element luciferase and phosphorylation-ER mutants that the effects of glyceollin arise from mechanisms distinct from conventional endocrine therapies. We show that glyceollin suppresses estrogen response element activity; however, it does not affect ER-alpha (α) phosphorylation levels. Additionally we show that glyceollin suppresses the phosphorylation of proteins known to crosstalk with ER signaling, specifically we demonstrate an inhibition of ribosomal protein S6 kinase, 70 kDa (p70S6) phosphorylation following glyceollin treatment. Our data suggests a mechanism for glyceollin inhibition of ERα through the induced suppression of p70S6 and demonstrates novel mechanisms for ER inhibition.

Effects of the endocrine-disrupting chemical DDT on self-renewal and differentiation of human mesenchymal stem cells.

BACKGROUND: Although the global use of the endocrine-disrupting chemical DDT has decreased, its persistence in the environment has resulted in continued human exposure. Accumulating evidence suggests that DDT exposure has long-term adverse effects on development, yet the impact on growth and differentiation of adult stem cells remains unclear. OBJECTIVES: Human mesenchymal stem cells (MSCs) exposed to DDT were used to evaluate the impact on stem cell biology. METHODS: We assessed DDT-treated MSCs for self-renewal, proliferation, and differentiation potential. Whole genome RNA sequencing was performed to assess gene expression in DDT-treated MSCs. RESULTS: MSCs exposed to DDT formed fewer colonies, suggesting a reduction in self-renewal potential. DDT enhanced both adipogenic and osteogenic differentiation, which was confirmed by increased mRNA expression of glucose transporter type 4 (GLUT4), lipoprotein lipase (LpL), peroxisome proliferator-activated receptor gamma (PPARγ), leptin, osteonectin, core binding factor 1 (CBFA1), and FBJ murine osteosarcoma viral oncogene homolog (c-Fos). Expression of factors in DDT-treated cells was similar to that in estrogen-treated MSCs, suggesting that DDT may function via the estrogen receptor (ER)-mediated pathway. The coadministration of ICI 182,780 blocked the effects of DDT. RNA sequencing revealed 121 genes and noncoding RNAs to be differentially expressed in DDT-treated MSCs compared with controls cells. CONCLUSION: Human MSCs provide a powerful biological system to investigate and identify the molecular mechanisms underlying the effects of environmental agents on stem cells and human health. MSCs exposed to DDT demonstrated profound alterations in self-renewal, proliferation, differentiation, and gene expression, which may partially explain the homeostatic imbalance and increased cancer incidence among those exposed to long-term EDCs.

Bisphenol A enhances adipogenic differentiation of human adipose stromal/stem cells.

Exposure of humans to the endocrine disrupter bisphenol A (BPA) has been associated with increased weight and obesity. However, the mechanism(s) by which BPA increases adipose tissue in humans remains to be determined. The goal of this study was to determine the effects of BPA on adipogenesis of cultured human adipose stromal/stem cells (ASCs), precursors to mature adipocytes. ASCs from three donors were cultured for either 14 or 21 days in adipogenic differentiation media containing increasing concentrations of BPA (100 pM-10 µM). The extent of adipogenic differentiation in the ASCs was assessed by staining with Oil Red O to visualize adipogenic differentiation and then quantified by extraction and optical density measurement of the retained dye. BPA significantly enhanced adipogenesis at a concentration of 1 µM after 21 days of culture. Additionally, we found that BPA increased transcription of the estrogen receptor (ER (ESR1)) and that treatment with the ER antagonist ICI 182 780, blocked the effects of BPA, indicating that BPA may act via an ER-mediated pathway. The results of molecular analyses indicated that the expression of the adipogenesis-associated genes dual leucine zipper-bearing kinase (DLK (MAP3K12)), IGF1, CCAAT/enhancer-binding protein alpha (C/EBPα (CEBPA)), peroxisome proliferator-activated receptor gamma (PPARγ (PPARG)), and lipoprotein lipase (LPL) was temporally accelerated and increased by BPA. In summary, these results indicate that BPA significantly enhances adipogenesis in ASCs through an ER-mediated pathway at physiologically relevant concentrations.

Phytoalexins, miRNAs and breast cancer: a review of phytochemical-mediated miRNA regulation in breast cancer.

There is growing interest in the diverse signaling pathways that regulate and affect breast tumorigenesis, including the role of phytochemicals and the emerging role of microRNAs (miRNAs). Recent studies demonstrate that miRNAs regulate fundamental cellular and developmental processes at the transcriptional and translational level under normal and disease conditions. While there is growing evidence to support the role of phytoalexin-mediated miRNA regulation of cancer, few reports address this role in breast cancer. Recent reports by our group and others demonstrate that natural products, including stilbenes, curcumin, and glyceollins, could alter the expression of specific miRNAs, which may lead to increased sensitivity of cancer cells to conventional anti-cancer agents and, therefore, hormone-dependent and hormone-independent tumor growth inhibition. This review will discuss how dietary intake of natural products, by regulating specific miRNAs, contribute to the prevention and treatment of breast cancer.

In vitro and in vivo evaluation of novel anticancer agents in triple negative breast cancer models.

Triple negative breast cancer (TNBC) is subtype of breast disease devoid of the estrogen, progesterone, and Her2/neu receptors which are targets for pharmacological intervention. There is a need for novel anti-breast cancer agents that target TNBC. Therefore, novel isochalcone DJ52 was evaluated using the alamar blue dye exclusion assay, the luciferase colony assay, and xenograft models to determine its efficacy and potency. DJ52 significantly decreased proliferation of cells measured by using the alamar blue dye method and produced IC50 values of DJ52, DJ56, and DJ82 at 10-6M, 10-5M, and 10-5M, respectively. In vivo studies were conducted by injecting MDA-MB-231 cells into SCID mice to determine tumor regression was measured over 20 days. DJ52 at 50 mg/kg caused significant decrease in tumor volume (p value <.05) by nearly 50% compared with the control with vehicle alone. These data suggest that DJ52 has merit for further evaluation as a novel anticancer agent.

Pharmacology and anti-tumor activity of RWJ67657, a novel inhibitor of p38 mitogen activated protein kinase.

Endocrine therapy resistance is a primary cause of clinical breast cancer treatment failure. The p38 mitogen activated protein kinase (MAPK) signaling pathway is known to promote ligand independent tumor growth and resistance to endocrine therapy. In this study, we investigated the therapeutic potential of the p38 inhibitor RWJ67657 in the treatment of tamoxifen resistant MDA-MB-361 cells. RWJ67657 dose-dependently decreased both basal and stimulated activation of p38 MAPK signaling in this drug resistant cell system. Decreased activation of p38 by RWJ67657 resulted in inhibition of the downstream p38 targets hsp27 and MAPKAPK. Diminished p38 signaling resulted in inhibition of p38-medated gene transcription. Furthermore, pharmacological inhibition of p38 by RWJ67657 decreased biological effects of p38, including ER-mediated gene expression and clonogenic survival in a dose-dependent manner. Animal studies revealed significantly decreased p38 signaling in vivo following exposure to RWJ67657. Treatment with the inhibitor markedly decreased phosphorylation of p38 in MDA-MB-361 tumors, leading to decreased transcription of both Fra-1 and progesterone receptor. Utilizing well-established xenograft tumor models, we demonstrated that RWJ67657 exhibits potent anti-tumor properties. Treatment with RWJ67657 markedly decreased tamoxifen resistant tumor growth, both in the presence and absence of estrogen. Taken together, our findings demonstrate the therapeutic potential of targeting the p38-MAPK signaling cascade in the treatment of endocrine resistant breast cancer.

The organochlorine o,p'-DDT plays a role in coactivator-mediated MAPK crosstalk in MCF-7 breast cancer cells.

BACKGROUND: The organochlorine dichlorodiphenyltrichloroethane (DDT), a known estrogen mimic and endocrine disruptor, has been linked to animal and human disorders. However, the detailed mechanism(s) by which DDT affects cellular physiology remains incompletely defined. OBJECTIVES: We and others have shown that DDT activates cell-signaling cascades, culminating in the activation of estrogen receptor-dependent and -independent gene expression. Here, we identify a mechanism by which DDT alters cellular signaling and gene expression, independent of the estrogen receptor. METHODS: We performed quantitative polymerase chain reaction array analysis of gene expression in MCF-7 breast cancer cells using either estradiol (E2) or o,p´-DDT to identify distinct cellular gene expression responses. To elucidate the mechanisms by which DDT regulates cell signaling, we used molecular and pharmacological techniques. RESULTS: E2 and DDT treatment both altered the expression of many of the genes assayed, but up-regulation of vascular endothelial growth factor A (VEGFA) was observed only after DDT treatment, and this increase was not affected by the pure estrogen receptor α antagonist ICI 182780. Furthermore, DDT increased activation of the HIF-1 response element (HRE), a known enhancer of the VEGFA gene. This DDT-mediated increase in HRE activity was augmented by the coactivator CBP (CREB-binding protein) and was dependent on the p38 pathway. CONCLUSIONS: DDT up-regulated the expression of several genes in MCF-7 breast cancer cells that were not altered by treatment with E2, including VEGFA. We propose that this DDT-initiated, ER-independent stimulation of gene expression is due to DDT's ability to initiate crosstalk between MAPK (mitogen-activated protein kinase) signaling pathways and transcriptional coactivators.

Gαo potentiates estrogen receptor α activity via the ERK signaling pathway.

The estrogen receptor α (ERα) is a transcription factor that mediates the biological effects of 17ß-estradiol (E(2)). ERα transcriptional activity is also regulated by cytoplasmic signaling cascades. Here, several Gα protein subunits were tested for their ability to regulate ERα activity. Reporter assays revealed that overexpression of a constitutively active Gα(o) protein subunit potentiated ERα activity in the absence and presence of E(2). Transient transfection of the human breast cancer cell line MCF-7 showed that Gα(o) augments the transcription of several ERα-regulated genes. Western blots of HEK293T cells transfected with ER±Gα(o) revealed that Gα(o) stimulated phosphorylation of ERK 1/2 and subsequently increased the phosphorylation of ERα on serine 118. In summary, our results show that Gα(o), through activation of the MAPK pathway, plays a role in the regulation of ERα activity.

Antiestrogenic activity of flavonoid phytochemicals mediated via the c-Jun N-terminal protein kinase pathway. Cell-type specific regulation of estrogen receptor alpha.

Flavonoid phytochemicals act as both agonists and antagonists of the human estrogen receptors (ERs). While a number of these compounds act by directly binding to the ER, certain phytochemicals, such as the flavonoid compounds chalcone and flavone, elicit antagonistic effects on estrogen signaling independent of direct receptor binding. Here we demonstrate both chalcone and flavone function as cell type-specific selective ER modulators. In MCF-7 breast carcinoma cells chalcone and flavone suppress ERα activity through stimulation of the stress-activated members of the mitogen-activated protein kinase (MAPK) family: c-Jun N-terminal kinase (JNK)1 and JNK2. The use of dominant-negative mutants of JNK1 or JNK2 in stable transfected cells established that the antiestrogenic effects of chalcone and flavone required intact JNK signaling. We further show that constitutive activation of the JNK pathway partially suppresses estrogen (E2)-mediated gene expression in breast, but not endometrial carcinoma cells. Our results demonstrate a role for stress-activated MAPKs in the cell type-specific regulation of ERα function.

Endocrine disruptor regulation of microRNA expression in breast carcinoma cells.

BACKGROUND: Several environmental agents termed "endocrine disrupting compounds" or EDCs have been reported to bind and activate the estrogen receptor-α (ER). The EDCs DDT and BPA are ubiquitously present in the environment, and DDT and BPA levels in human blood and adipose tissue are detectable in most if not all women and men. ER-mediated biological responses can be regulated at numerous levels, including expression of coding RNAs (mRNAs) and more recently non-coding RNAs (ncRNAs). Of the ncRNAs, microRNAs have emerged as a target of estrogen signaling. Given the important implications of EDC-regulated ER function, we sought to define the effects of BPA and DDT on microRNA regulation and expression levels in estrogen-responsive human breast cancer cells. METHODOLOGY/PRINCIPAL FINDINGS: To investigate the cellular effects of DDT and BPA, we used the human MCF-7 breast cancer cell line, which is ER (+) and hormone sensitive. Our results show that DDT and BPA potentiate ER transcriptional activity, resulting in an increased expression of receptor target genes, including progesterone receptor, bcl-2, and trefoil factor 1. Interestingly, a differential increase in expression of Jun and Fas by BPA but not DDT or estrogen was observed. In addition to ER responsive mRNAs, we investigated the ability of DDT and BPA to alter the miRNA profiles in MCF-7 cells. While the EDCs and estrogen similarly altered the expression of multiple microRNAs in MCF-7 cells, including miR-21, differential patterns of microRNA expression were induced by DDT and BPA compared to estrogen. CONCLUSIONS/SIGNIFICANCE: We have shown, for the first time, that BPA and DDT, two well known EDCs, alter the expression profiles of microRNA in MCF-7 breast cancer cells. A better understanding of the molecular mechanisms of these compounds could provide important insight into the role of EDCs in human disease, including breast cancer.

Environmental signaling and reproduction: a comparative biological and chemical perspective.

Reproduction is a critical element of life. Self-propagation in all living organisms ranging from bacteria to humans involves numerous common strategies. Underlying all reproductive strategies is the essential need for signaling molecules to initiate and maintain the process. In this paper we use comparative biological and chemical approaches to explore the origins and distribution of estrogen signaling as a pathway common to many life forms. In the process we illuminate the mechanisms whereby environmental agents alter reproduction and development. These mechanisms involve altered signaling pathways within cells and shifts in the targets of the signaling pathways to include regulators of gene transcription normally associated with other pathways. We also stress the role of signal cross talk in mediating hormone action.

Estrogenic and antiestrogenic activities of phytoalexins from red kidney bean (Phaseolus vulgaris L.).

Legumes are the predominant source of isoflavones considered to be phytoestrogens that mimic the hormone 17ß-estradiol (E2). Due to the risks associated with hormone replacement therapy, there is a growing need for alternative sources of estrogenic formulations for the treatment of menopausal symptoms. Legume phytoalexins (induced isoflavones) are produced under conditions of stress that include insect damage, wounding, or application of elicitors. The estrogenic and antiestrogenic activities of methanolic extracts obtained from red kidney bean treated with the fungus Aspergillus sojae were compared with those of untreated controls using an estrogen responsive element-based (ERE) luciferase reporter assay. A. sojae-treated red kidney bean extracts displayed both estrogenic and antiestrogenic activities. Analysis of elicitor-treated red kidney bean extracts showed that A. sojae treatments achieved maximal levels of kievitone at 1199 ± 101 µg/g and phaseollin at 227.8 ± 44 µg/g. The phytoalexins kievitone and phaseollin were isolated from A. sojae-treated red kidney bean extracts and analyzed for estrogenic activity using ERα and ERß binding, ERE luciferase assays in MCF-7 and HEK 293 cells, and MCF-7 cell proliferation. Kievitone showed the highest relative binding affinity to ERα with kievitone (0.48%) > phaseollin (0.21%), and phaseollin showed the highest relative binding affinity to ERß with phaseollin (0.53%) > kievitone (0.42%). In an ERE luciferase assay in MCF-7 cells, kievitone displayed high ER transactivation at 10 µM; phaseollin displayed low ER transactivation. Both kievitone and phaseollin stimulated MCF-7 cell proliferation, with kievitone displaying agonist activity between 0.1 and 10 µM. Cotransfection reporter assays performed in HEK 293 demonstrated that phaseollin selectively increased ERE transcriptional activity of ERß and kievitone selectively increased ERE transcriptional activity of ERα. Although phaseollin displayed attenuation of ER transactivation in the ERE luciferase assay in MCF-7 cells, both phytoalexins attenuated the effects of E2 in an MCF-7 cell colonial survival assay. This work provides evidence that the red kidney bean phytoalexins kievitone and phaseollin possess both estrogenic and antiestrogenic activities.

Effects of 7-O substitutions on estrogenic and anti-estrogenic activities of daidzein analogues in MCF-7 breast cancer cells.

Daidzein (1) is a natural estrogenic isoflavone. We report here that 1 can be transformed into anti-estrogenic ligands by simple alkyl substitutions of the 7-hydroxyl hydrogen. To test the effect of such structural modifications on the hormonal activities of the resulting compounds, a series of daidzein analogues have been designed and synthesized. When MCF-7 cells were treated with the analogues, those resulting from hydrogen substitution by isopropyl (3d), isobutyl (3f), cyclopentyl (3g), and pyrano- (2) inhibited cell proliferation, estrogen-induced transcriptional activity, and estrogen receptor (ER) regulated progesterone receptor (PgR) gene expression. However, methyl (3a) and ethyl (3b) substitutions of the hydroxyl proton only led to moderate reduction of the estrogenic activities. These results demonstrated the structural requirements for the transformation of daidzein from an ER agonist to an antagonist. The most effective analogue, 2, was found to reduce in vivo estrogen stimulated MCF-7 cell tumorigenesis using a xenograft mouse model.

Regulation of ERalpha-mediated transcription of Bcl-2 by PI3K-AKT crosstalk: implications for breast cancer cell survival.

Both estrogen, through the estrogen receptor (ER), and growth factors, through the phosphatidylinositol-3-kinase (PI3K)-AKT pathway, have been shown to independently promote cell survival. Here, we investigated the role of ER/PI3K-AKT crosstalk in the regulation of cell survival in MCF-7 breast carcinoma cells. The ER inhibitor ICI 182,780 was used to determine the requirement of the ER for estrogen in the suppression of tumor necrosis factor-alpha (TNFalpha) induced apoptosis. Gene reporter assays and Western blot analyses were used to determine the involvement of the pro-survival factor Bcl-2 and the coactivator GRIP1 in this survival crosstalk. We demonstrated that an intact ER signaling pathway was required for estrogen to suppress apoptosis induced by TNFalpha. Our gene reporter assays revealed that ERalpha, not ERbeta, was targeted by AKT, resulting in transcriptional potentiation of the full-length Bcl-2 promoter, ultimately leading to increased Bcl-2 protein levels. AKT targeted both activation function (AF) domains of the ERalpha for maximal induction of Bcl-2 reporter activity, although the AF-II domain was predominately targeted. In addition, AKT also caused an upregulation of GRIP1 protein levels. Finally, AKT and GRIP1 cooperated to increase Bcl-2 protein expression to a greater level than either factor alone. Collectively, our study suggests a role for ER/PI3K-AKT crosstalk in cell survival and documents the ability of AKT to regulate Bcl-2 expression via differential activation of ERalpha and ERbeta as well as regulation of GRIP1.

Environmental hormones: Multiple pathways for response may lead to multiple disease outcomes.

Compounds that mimic vertebrate hormone responses are found throughout the environment, and some are implicated in endocrine disruption. Endocrine disruption has been found in humans, wildlife, and even in the partnership of plants and root symbionts. Most endocrine disruption occurs in estrogenic systems. Estrogens, like other steroid hormones, binds a transcription factor known as a nuclear receptor to regulate gene transcription. Recent research has shown that there are other signaling mechanisms for steroid hormones that involve kinase pathways and G protein-coupled receptors. Mounting evidence suggests estrogen mimics can also act by these pathways which work outside the nucleus. Differential expression of these pathways across cell types, and differential affinity for these pathways by diverse compounds may explain some patterns of endocrine disruption and disease.

Glyceollin I enantiomers distinctly regulate ER-mediated gene expression.

Glyceollins are pterocarpan phytoalexins elicited in high concentrations when soybeans are stressed. We have previously reported that the three glyceollin isomers (GLY I-III) exhibit antiestrogenic properties, which may have significant biological effects upon human exposure. Of the three isomers, we have recently shown that glyceollin I is the most potent antiestrogen. Natural (-)-glyceollin I recently was synthesized along with its racemate and unnatural (+) enantiomer. In this study, we compared the glyceollin I enantiomers' ER binding affinity, ability to inhibit estrogen responsive element transcriptional (ERE) activity and endogenous gene expression in MCF-7 cells. The results demonstrated similar binding affinities for both ERalpha and ERbeta. Reporter gene assays in MCF-7 cells revealed that while (+)-glyceollin I slightly stimulated ERE transcriptional activity, (-)-glyceollin I decreased activity induced by estrogen. Co-transfection reporter assays performed in HEK 293 cells demonstrated that (+)-glyceollin I increased ERE transcriptional activity of ERalpha and ERbeta with and without estrogen with no antiestrogenic activity observed. Conversely, (-)-glyceollin I decreased the activity of both ER subtypes stimulated by estradiol demonstrating potent antiestrogenic properties. Additionally, each Gly I enantiomer induced unique gene expression profiles in a PCR array panel of genes commonly altered in breast cancer.

Glyceollin I, a novel antiestrogenic phytoalexin isolated from activated soy.

Glyceollins, a group of novel phytoalexins isolated from activated soy, have recently been demonstrated to be novel antiestrogens that bind to the estrogen receptor (ER) and inhibit estrogen-induced tumor progression. Our previous publications have focused specifically on inhibition of tumor formation and growth by the glyceollin mixture, which contains three glyceollin isomers (I, II, and III). Here, we show the glyceollin mixture is also effective as a potential antiestrogenic, therapeutic agent that prevents estrogen-stimulated tumorigenesis and displays a differential pattern of gene expression from tamoxifen. By isolating the individual glyceollin isomers (I, II, and III), we have identified the active antiestrogenic component by using competition binding assays with human ERalpha and in an estrogen-responsive element-based luciferase reporter assay. We identified glyceollin I as the active component of the combined glyceollin mixture. Ligand-receptor modeling (docking) of glyceollin I, II, and III within the ERalpha ligand binding cavity demonstrates a unique type II antiestrogenic confirmation adopted by glyceollin I but not isomers II and III. We further compared the effects of glyceollin I to the antiestrogens, 4-hydroxytamoxifen and ICI 182,780 (fulvestrant), in MCF-7 breast cancer cells and BG-1 ovarian cancer cells on 17beta-estradiol-stimulated expression of progesterone receptor and stromal derived factor-1alpha. Our results establish a novel inhibition of ER-mediated gene expression and cell proliferation/survival. Glyceollin I may represent an important component of a phytoalexin-enriched food (activated) diet in terms of chemoprevention as well as a novel therapeutic agent for hormone-dependent tumors.