Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P04155 (pS2)
 1,234 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This study compared expression of two estrogen receptor (ER alpha and ER beta) genes in the rat upper gastrointestinal tract and the effects of 17 beta-estradiol administration on gastric trefoil factor family (TFF) mRNA steady-state levels in ovariectomized rats. Estrogen receptor alpha and beta cDNA fragments from fundic mucosa were cloned by reverse transcriptase polymerase chain reaction (RT-PCR) and sequenced. Both ER subtypes were detected in fundus, antrum and duodenum by RT-PCR. Northern analysis of poly(A)+ mRNA from fundic mucosa showed that ER alpha mRNA is expressed as a single transcript at 6.5 kb and ER beta is expressed as multiple transcripts with major transcripts ranging from 1.1-4.7 kb. ER beta mRNA was expressed in greater abundance than ER alpha mRNA. Fundic TFF2 mRNA steady-state levels were increased by 17 beta-estradiol administration in ovariectomized rats with no significant change in TFF1 mRNA levels. These studies show expression of both ER subtypes in the rat upper gastrointestinal tract with regulation of TFF2 mRNA by 17 beta-estradiol. These results suggest that estrogens, probably acting via ER beta, have a direct role in regulating gastric physiology.
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PMID:Estrogen receptor alpha and beta expression in upper gastrointestinal tract with regulation of trefoil factor family 2 mRNA levels in ovariectomized rats. 938 4

Estrogens act as potent mitogens in a large number of breast cancers, and the use of estrogen receptor (ER) antagonists is, therefore, considered the endocrine therapy of choice in the management of this disease. We describe the molecular properties of EM-652, the active metabolite of EM-800, a novel nonsteroidal antiestrogen compound, on the transcriptional functions of ER alpha and ER beta. Using RT-PCR, we show that ER alpha and ER beta are expressed in mouse mammary glands, suggesting that both receptors should be considered putative targets for antiestrogen action in the breast. In cotransfection assays using a synthetic estrogen-responsive promoter, EM-652 shows no agonistic activity on ER alpha and ER beta transcriptional function and blocks the estradiol (E2)-mediated activation of both ER alpha and ER beta. EM-652 is also very effective in abrogating E2-stimulated ER alpha and ER beta trans-activation of the pS2 promoter in HeLa cells. EM-652 does not alter binding of ER alpha and ER beta to DNA. The Ras-mediated induction of ER alpha and ER beta transcriptional activity in the presence of E2 is also completely abolished by EM-652. In addition, EM-652 blocks the E2-dependent activation of ER alpha and ER beta by the steroid hormone receptor coactivator-1 as well as the in vitro interaction between SRC-1 and the ligand-binding domains of both ERs. These results demonstrate that the novel antiestrogen EM-800 fully impedes AF-1 and AF-2 activities of ER alpha and ER beta and can, therefore, be considered a potent and pure antagonist of both ER subtypes.
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PMID:EM-800, a novel antiestrogen, acts as a pure antagonist of the transcriptional functions of estrogen receptors alpha and beta. 942 5

Estrogen receptors are derived from two different gene products referred to as estrogen receptor-alpha (ER-alpha) and ER-beta. Both receptors bind to the consensus estrogen response element (ERE) present in the vitellogenin gene, but their binding to hormone response elements present in other estrogen responsive genes has not been reported yet. Using in vitro expressed human receptors, we now show that ER-beta binds to a panel of six endogenous hormone response elements (vitellogenin, c-fos, c-jun, pS2, cathepsin D, and choline acetyltransferase) already known to bind ER-alpha and confer estrogen inducibility to reporter constructs. Binding of ER-alpha and ER-beta occurred at similar DNA concentrations for some EREs, but different DNA concentrations were required to form complexes of the two receptors with other elements. These results illustrate for the first time by direct receptor-DNA binding studies that both ER-alpha and ER-beta bind to a number of EREs present in endogenous hormone regulated genes, and further suggest that the two forms of the receptor display different patterns of affinities for naturally occurring hormone response elements.
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PMID:Interaction of human estrogen receptors alpha and beta with the same naturally occurring estrogen response elements. 1003 43

To determine the molecular mechanisms underlying the "cross talk" between the activity of 2,3,7,8-tetra-chlorodibenzo-p-dioxin (TCDD), which binds to arylhydrocarbon receptor (AHR) and estradiol (E2)-liganded estrogen receptor (ER), we first examined the initial step of estrogen action, ligand binding to ER. None of the AHR ligands tested, i.e. TCDD, benzo[a]pyrene, 3,3',4,4',5-pentachlorobiphenyl, beta-naphthoflavone, or alpha-naphthoflavone, bound to ER alpha. We report the first examination of TCDD interaction with ER beta: TCDD did not displace E2 from ER beta. We then examined a second possible mechanism, i.e. direct inhibition of ER alpha binding to estrogen response elements (EREs) by the AHR/AHR nuclear translocator (ARNT) complex. The AHR/ARNT heterodimer did not bind either a full or half-site ERE. However, AHR/ARNT bound specifically to oligomers containing naturally occurring EREs derived from the human c-fos, pS2, and progesterone receptor (PR) gene promoters that include xenobiotic response element (XRE)-like sequences. In contrast, neither purified E2-liganded-ER from calf uterus or recombinant human ER alpha bound a consensus XRE. TCDD inhibited E2-activated reporter gene activity from a consensus ERE and from EREs in the pS2, PR, and Fos genes in transiently transfected MCF-7 human breast cancer cells. However, this inhibition was not reciprocal since E2 did not inhibit TCDD-stimulated luciferase activity from the CYP1A1 promoter in transiently transfected MCF-7 or human endometrial carcinoma HEC-1A cells. We propose that at least part of the mechanism by which the AHR/ARNT complex inhibits estrogen action is by competitively inhibiting ER alpha binding to imperfect ERE sites, adjacent to or overlapping XREs.
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PMID:The aryl hydrocarbon receptor (AHR)/AHR nuclear translocator (ARNT) heterodimer interacts with naturally occurring estrogen response elements. 1061 2

The aim of the current study is to demonstrate normal and malignant prostatic epithelial cells (PrECs) as targets for receptor-mediated estrogenic and antiestrogenic action. Using an improved protocol, we have successfully isolated and maintained highly enriched populations of normal PrECs from ultrasound-guided peripheral zone biopsies, individually determined to be morphologically normal. Semiquantitative reverse transcription-PCR analyses were used to determine whether transcripts of estrogen receptor (ER)-alpha and those of ER-beta were expressed in our normal PrEC primary cultures, in a commercially available PrEC preparation (PrEC; Clontech), in an immortalized PrEC line established from a benign prostatic hyperplasia specimen (BPH-1), and in three prostatic cancer cell lines (LNCaP, PC-3, and DU145). Expression levels of ER-alpha and ER-beta transcripts were related to those of two estrogen-responsive genes [progesterone receptor (PR) and pS2], at the message levels, to gain insights into the functionality of the ER subtypes in PrECs. Interestingly, only transcripts of ER-beta, but not those of ER-alpha, were found in our primary cultures of normal PrECs, along with both PR and pS2 mRNA. These data strongly suggest that estrogen action was signaled exclusively via ER-beta in normal human PrECs. In contrast, PrEC (Clontech) and BPH-1 cells expressed both ER-alpha and ER-beta transcripts and no PR nor pS2 mRNA in PrEC and only a minimal level of PR mRNA in BPH-1. Among the three prostate cancer cell lines, LNCaP expressed ER-beta mRNA along with transcripts of PR and pS2, DU145 expressed messages of ER-beta and PR, and PC-3 cells exhibited ER-alpha, ER-beta, and pS2 mRNA. Thus, unlike normal PrECs, expression patterns of these genes in malignant PrECs are more variable. Treatment of prostate cancer cells with demethylation agents effectively reactivated the expression of ER-alpha mRNA in LNCaP and DU145 and that of pS2 message in DU145. These findings provide experimental evidence that ER-alpha gene silencing in prostate cancer cells, and perhaps also in normal PrECs, are caused by DNA hypermethylation. To evaluate the potential of using antiestrogens as prostate cancer therapies, we have assessed the growth-inhibitory action of estrogens (estradiol and diethylstilbestrol) and antiestrogens (4-hydroxy-tamoxifen and ICI-182,780) on PC-3 and DU-145 cells. In PC-3 cells, which express both ER subtypes, estrogens as well as antiestrogens are effective inhibitors. In contrast, in DU145 cells, which express only ER-beta, antiestrogens, but not estrogens, are growth inhibitors. By comparison, ICI 182,780 is the more effective cell growth inhibitor. Importantly, the ICI 182,780-induced antiproliferative effects were reversed by cotreatment of DU145 cells with an ER-beta antisense oligonucleotide, hence lending additional support to a central role played by ER-beta in mediating growth-inhibitory action of antiestrogens.
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PMID:Expression of estrogen receptor (ER)-alpha and ER-beta in normal and malignant prostatic epithelial cells: regulation by methylation and involvement in growth regulation. 1086 8

Cruciferous vegetable extracts from freeze-dried cabbage (FDC), freeze-dried fermented cabbage (FDS), and acidified Brussels sprouts (ABS) were prepared by exhaustive extraction with ethyl acetate. Estrogenic and antiestrogenic effects of these extracts were analyzed. To identify whether the extracts are potential estrogen receptor (ER) ligands that can act as agonists or antagonists, the binding affinity of extracts for the ER was measured using a competitive radiometric binding assay. The extracts bound with low affinity to the ER, and the relative binding affinity is estradiol > FDS > FDC > ABS. These extracts were evaluated for their estrogenic and antiestrogenic activities in estrogen-dependent human breast cancer (MCF-7) cells using as endpoints proliferation and induction of estrogen-responsive pS2 gene expression, which was analyzed using Northern blot assay. At low concentrations (5-25 ng/mL) all of the extracts reduced 1 nM estradiol-induced MCF-7 cell proliferation. Extracts at 25 ng/mL also inhibited estradiol-induced pS2 mRNA expression. At higher extract concentrations (50 ng/mL-25 microg/mL), however, increased proliferation in MCF-7 cells was observed. Similarly, expression of the pS2 gene was induced by higher extract concentrations (0.25-25 microg/mL). The pure estrogen antagonist, ICI 182,780, suppressed the cell proliferation induced by the extracts as well as by estradiol and also the induction of pS2 expression by the extracts. The ER subtype-selective activities of FDC and FDS were analyzed using a transfection assay in human endometrial adenocarcinoma (HEC-1) cells. FDS acted as an ERalpha-selective agonist while FDC fully activated both ER-alpha and ER-beta. Growth of the ER-negative MDA-231 cells was not affected by the extracts or by estradiol. This study demonstrates that cruciferous vegetable extracts act bifunctionally, like an antiestrogen at low concentrations and an estrogen agonist at high concentrations.
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PMID:Estrogenic effects of extracts from cabbage, fermented cabbage, and acidified brussels sprouts on growth and gene expression of estrogen-dependent human breast cancer (MCF-7) cells. 1105 10

Eight botanical preparations that are commonly used for the treatment of menopausal symptoms were tested for estrogenic activity. Methanol extracts of red clover (Trifolium pratense L.), chasteberry (Vitex agnus-castus L.), and hops (Humulus lupulus L.) showed significant competitive binding to estrogen receptors alpha (ER alpha) and beta (ER beta). With cultured Ishikawa (endometrial) cells, red clover and hops exhibited estrogenic activity as indicated by induction of alkaline phosphatase (AP) activity and up-regulation of progesterone receptor (PR) mRNA. Chasteberry also stimulated PR expression, but no induction of AP activity was observed. In S30 breast cancer cells, pS2 (presenelin-2), another estrogen-inducible gene, was up-regulated in the presence of red clover, hops, and chasteberry. Interestingly, extracts of Asian ginseng (Panax ginseng C.A. Meyer) and North American ginseng (Panax quinquefolius L.) induced pS2 mRNA expression in S30 cells, but no significant ER binding affinity, AP induction, or PR expression was noted in Ishikawa cells. Dong quai [Angelica sinensis (Oliv.) Diels] and licorice (Glycyrrhiza glabra L.) showed only weak ER binding and PR and pS2 mRNA induction. Black cohosh [Cimicifuga racemosa (L.) Nutt.] showed no activity in any of the above in vitro assays. Bioassay-guided isolation utilizing ER competitive binding as a monitor and screening using ultrafiltration LC-MS revealed that genistein was the most active component of red clover. Consistent with this observation, genistein was found to be the most effective of four red clover isoflavones tested in the above in vitro assays. Therefore, estrogenic components of plant extracts can be identified using assays for estrogenic activity along with screening and identification of the active components using ultrafiltration LC-MS. These data suggest a potential use for some dietary supplements, ingested by human beings, in the treatment of menopausal symptoms.
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PMID:Evaluation of estrogenic activity of plant extracts for the potential treatment of menopausal symptoms. 1136 22

Recent studies indicate that the expression of ER beta in breast cancer is lower than in the normal breast, suggesting that ER beta could play an important role in carcinogenesis. To investigate this hypothesis, we engineered ER-negative MDA-MB-231 (human breast cancer cells) to reintroduce either ER alpha or ER beta protein with an adenoviral vector. In these cells, ER beta (as ER alpha) expression was monitored using RT-PCR and Western blot. ER beta protein was localized in the nucleus (immunocytochemistry) and able to transactivate estrogen-responsive reporter constructs in the presence of E2. ER beta and ER alpha induced the expression of several endogenous genes such as pS2, TGF alpha, or the cyclin kinase inhibitor p21 but, in contrast to ER alpha, ER beta was unable to regulate c-myc proto-oncogene expression. The pure antiestrogen ICI 164, 384 completely blocked ER alpha and ER beta estrogen-induced activities. ER beta inhibited MDA-MB-231 cell proliferation in a ligand-independent manner, whereas ER alpha inhibition of proliferation is hormone dependent. Moreover, ER beta and ER alpha decreased cell motility and invasion. Our data bring the first evidence that ER beta is an important modulator of proliferation and invasion of breast cancer cells and support the hypothesis that the loss of ER beta expression could be one of the events leading to the development of breast cancer.
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PMID:ER beta inhibits proliferation and invasion of breast cancer cells. 1151 91

Estrogen receptor beta (ERbeta) activates transcription by binding to estrogen response elements (EREs) and coactivator proteins that act as bridging proteins between the receptor and the basal transcription machinery. Although the imperfect vitellogenin B1, pS2, and oxytocin (OT) EREs each differ from the consensus vitellogenin A2 ERE sequence by a single base pair, ERbeta activates transcription of reporter plasmids containing A2, pS2, B1, and OT EREs to different extents. To explain how these differences in transactivation might occur, we have examined the interaction of ERbeta with these EREs and monitored recruitment of the coactivators amplified in breast cancer (AIB1) and transcription intermediary factor 2 (TIF2). Protease sensitivity, antibody interaction, and DNA pull-down assays demonstrated that ERbeta undergoes ERE-dependent changes in conformation resulting in differential recruitment of AIB1 and TIF2 to the DNA-bound receptor. Overexpression of TIF2 or AIB1 in transient transfection assays differentially enhanced ERbeta-mediated transcription of reporter plasmids containing the A2, pS2, B1, and OT EREs. Our studies demonstrate that individual ERE sequences induce changes in conformation of the DNA-bound receptor and influence coactivator recruitment. DNA-induced modulation of receptor conformation may contribute to the ability of ERbeta to differentially activate transcription of genes containing divergent ERE sequences.
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PMID:Estrogen response elements alter coactivator recruitment through allosteric modulation of estrogen receptor beta conformation. 1157 41

When estrogen binds its receptor (ER), it becomes a potent mitogen in a number of target tissues including the mammary gland where it plays an important role in the pathogenesis of mammary carcinoma. Arsenic trioxide (AS2O3), a clinically effective agent against acute promyelocytic leukemia, has been shown to induce apoptosis in a variety of cancer cells in vitro. Here, we investigated the effects of AS2O3 on the growth of two ER-positive breast cancer cell lines, MCF7 and T47D in vitro. We found that higher doses of AS2O3 dramatically reduced the survival of these two breast cancer cell lines while lower doses of AS2O3 significantly inhibited the expression of estrogen receptor alpha (ER-alpha), but did not effect ER-beta expression. The ER-alpha expression is totally restored when AS2O3 is absent for 24 hours. Using a reporter gene controlled by ER, we further demonstrated that AS2O3 strongly-repressed 17beta-estradiol (E2) stimulated-transcriptional activation. Moreover, AS2O3 abolished transcriptional induction of the estrogen responsive gene pS2 mediated by E2. These results indicated that AS2O3 specifically inhibits expression and signaling pathway of the ER-alpha. We suggest that AS2O3 in combination with other methods might provide a novel therapeutic approach for ER-alpha-positive breast cancer.
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PMID:Functional repression of estrogen receptor a by arsenic trioxide in human breast cancer cells. 1201 31


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