Showing papers by "Benita S. Katzenellenbogen published in 2001"
TL;DR: A novel paradigm of sex steroid action on osteoblasts, osteocytes, embryonic fibroblasts, and HeLa cells involving activation of a Src/Shc/ERK signaling pathway and attenuating apoptosis is demonstrated, providing proof of principle for the development of function-specific-as opposed to tissue-selective-and gender-neutral pharmacotherapeutics.
1,203 citations
TL;DR: This study suggests that, in this series of ligands, the nitrile functionality is critical to ERbeta selectivity because it provides the optimal combination of linear geometry and polarity.
Abstract: Through an effort to develop novel ligands that have subtype selectivity for the estrogen receptors alpha (ERalpha) and beta (ERbeta), we have found that 2,3-bis(4-hydroxyphenyl)propionitrile (DPN) acts as an agonist on both ER subtypes, but has a 70-fold higher relative binding affinity and 170-fold higher relative potency in transcription assays with ERbeta than with ERalpha. To investigate the ERbeta affinity- and potency-selective character of this DPN further, we prepared a series of DPN analogues in which both the ligand core and the aromatic rings were modified by the repositioning of phenolic hydroxy groups and by the addition of alkyl substituents and nitrile groups. We also prepared other series of DPN analogues in which the nitrile functionality was replaced with acetylene groups or polar functions, to mimic the linear geometry or polarity of the nitrile, respectively. To varying degrees, all of the analogues show preferential binding affinity for ERbeta (i.e., they are ERbeta affinity-selective), and many, but not all of them, are also more potent in activating transcription through ERbeta than through ERalpha (i.e., they are ERbeta potency-selective). meso-2,3-Bis(4-hydroxyphenyl)succinonitrile and dl-2,3-bis(4-hydroxyphenyl)succinonitrile are among the highest ERbeta affinity-selective ligands, and they have an ERbeta potency selectivity that is equivalent to that of DPN. The acetylene analogues have higher binding affinities but somewhat lower selectivities than their nitrile counterparts. The polar analogues have lower affinities, and only the fluorinated polar analogues have substantial affinity selectivities. This study suggests that, in this series of ligands, the nitrile functionality is critical to ERbeta selectivity because it provides the optimal combination of linear geometry and polarity. Furthermore, the addition of a second nitrile group beta to the nitrile in DPN or the addition of a methyl substitutent at an ortho position on the beta-aromatic ring increases the affinity and selectivity of these compounds for ERbeta. These ERbeta-selective compounds may prove to be valuable tools in understanding the differences in structure and biological function of ERalpha and ERbeta.
687 citations
TL;DR: It is shown that the estrogen receptor (ERα) is acetylated in vivo, and the conservation of the ERα acetylation motif in a phylogenetic subset of nuclear receptors suggests that direct acetylators may contribute to additional signaling pathways involved in metabolism and development.
355 citations
Journal Article•
TL;DR: The present findings indicate that ERα is the dominant ER form mediating the developmental estrogenization of the prostate gland and if epithelial ERβ is involved in some component of estrogen imprinting, its role would be considered minor and would require the presence of ERα expression in the prostatic stromal cells.
Abstract: Neonatal exposure of rodents to high doses of estrogen permanently imprints the growth and function of the prostate and predisposes this gland to hyperplasia and severe dysplasia analogous to prostatic intraepithelial neoplasia with aging. Because the rodent prostate gland expresses estrogen receptor (ER)-α within a subpopulation of stromal cells and ERβ within epithelial cells, the present study was undertaken to determine the specific ER(s) involved in mediating prostatic developmental estrogenization. Wild-type (WT) mice, homozygous mutant ER (ERKO) α −/− mice, and βERKO −/− mice were injected with 2 μg of diethylstilbestrol (DES) or oil (controls) on days 1, 3, and 5 of life. Reproductive tracts were excised on days 5 or 10 (prepubertal), day 30 (pubertal), day 90 (young adult), or with aging at 6, 12, and 18 months of age. Prostate complexes were microdissected and examined histologically for prostatic lesions and markers of estrogenization. Immunocytochemistry was used to examine expression of androgen receptor, ERα, ERβ, cytokeratin 14 (basal cells), cytokeratin 18 (luminal cells), and dorsolateral protein over time in the treated mice. In WT-DES mice, developmental estrogenization of the prostate was observed at all of the time points as compared with WT-oil mice. These prostatic imprints included transient up-regulation of ERα, down-regulation of androgen receptor, decreased ERβ levels in adult prostate epithelium, lack of DLP secretory protein, and a continuous layer of basal cells lining the ducts. With aging, epithelial dysplasia and inflammatory cell infiltrate were observed in the ventral and dorsolateral prostate lobes. In contrast, the prostates of αERKO mice exhibited no response to neonatal DES either immediately after exposure or throughout life up to 18 months of age. Furthermore, neonatal DES treatment of βERKO mice resulted in a prostatic response similar to that observed in WT animals. The present findings indicate that ERα is the dominant ER form mediating the developmental estrogenization of the prostate gland. If epithelial ERβ is involved in some component of estrogen imprinting, its role would be considered minor and would require the presence of ERα expression in the prostatic stromal cells.
278 citations
TL;DR: Of the systems investigated, the tetrasubstituted furans proved to be most interesting, with the triphenolic 3-alkyl-2,4,5-tris(4-hydroxyphenyl)furans (15a−d) displaying generally higher subtype binding selectivity than the bisphenolic analogues.
Abstract: A variety of nonsteroidal systems can function as ligands for the estrogen receptor (ER), in some cases showing selectivity for one of the two ER subtypes, ERα or ERβ. We have prepared a series of heterocycle-based (furans, thiophenes, and pyrroles) ligands for the estrogen receptor and assessed their behavior as ER ligands. An aldehyde enone conjugate addition approach and an enolate alkylation approach were developed to prepare the 1,4-dione systems that were precursors to the trisubstituted and tetrasubstituted systems, respectively. All of the diones were easily converted into the corresponding furans, but formation of the thiophenes and pyrroles from the more highly substituted 1,4-diones was problematical. Of the systems investigated, the tetrasubstituted furans proved to be most interesting. They were ERα binding- and potency-selective agents, with the triphenolic 3-alkyl-2,4,5-tris(4-hydroxyphenyl)furans (15a−d) displaying generally higher subtype binding selectivity than the bisphenolic analogues...
219 citations
TL;DR: It is shown that estrogen regulates expression of the Na+/H+ exchanger-3 (NHE3) and the rate of 22Na+ transport, sensitive to an NHE3 inhibitor, and this raises the possibility of targeting ERα in developing a contraceptive for the male.
Abstract: Estrogen receptor α (ERα) is essential for male fertility. Its activity is responsible for maintaining epithelial cytoarchitecture in efferent ductules and the reabsorption of fluid for concentrating sperm in the head of the epididymis. These discoveries and others have helped to establish estrogen's bisexual role in reproductive importance. Reported here is the molecular mechanism to explain estrogen's role in fluid reabsorption in the male reproductive tract. It is shown that estrogen regulates expression of the Na+/H+ exchanger-3 (NHE3) and the rate of 22Na+ transport, sensitive to an NHE3 inhibitor. Immunohistochemical staining for NHE3, carbonic anhydrase II (CAII), and aquaporin-I (AQP1) was decreased in ERα knockout (αERKO) efferent ductules. Targeted gene-deficient mice were compared with αERKO, and the NHE3 knockout and CAII-deficient mice showed αERKO-like fluid accumulation, but only the NHE3 knockout and αERKO mice were infertile. Northern blot analysis showed decreases in mRNA for NHE3 in αERKO and antiestrogen-treated mice. The changes in AQP1 and CAII in αERKO seemed to be secondary because of the disruption of apical cytoarchitecture. Ductal epithelial ultrastructure was abnormal only in αERKO mice. Thus, in the male, estrogen regulates one of the most important epithelial ion transporters and maintains epithelial morphological differentiation in efferent ductules of the male, independent of its regulation of Na+ transport. Finally, these data raise the possibility of targeting ERα in developing a contraceptive for the male.
191 citations
TL;DR: Results show that ERβ mediates transcriptional activation of eNOS and iNOS by E2, which is completely blocked by R,R‐THC as shown by immunoblot analysis.
111 citations
TL;DR: Fink et al. as discussed by the authors developed a triaryl-substituted pyrazole ligand system that has high affinity for the estrogen receptor (ER) and showed that the most favorable orientation appears to be one which places the N(1) phenol in the A-ring binding pocket so that the basic side chain can adopt an orientation similar to those typically found in antiestrogens and known to be essential determinants of their mixed agonist/antagonist character.
82 citations
TL;DR: It is proposed that activated CREB is recruited to estrogen responsive genes by an ER--coactivator complex containing proteins such as CREB binding protein (CBP) and that the interaction of CREB with ER may assist in stabilizing its interaction with CBP and in promoting estrogen-ER and PKA transcriptional synergy.
74 citations
TL;DR: It is reported that estrogen can up-regulate the expression of the serotonin-1A receptor via a new mechanism involving synergistic activation by nuclear factor-κB (NF-κBs) with estrogen receptor α, and that only estrogen receptor-α, and not -β, was able to mediate this effect of estrogens.
Abstract: Estrogen exerts profound effects on mood and mental state. The ability of estrogen to modulate serotonergic function raises the possibility that it may play a role in the mechanism associated with depression and its treatment. A cellular mechanism for estrogen to influence mood might be through the regulation of genes involved at various levels of the serotonin system. Here we report that estrogen can up-regulate the expression of the serotonin-1A receptor via a new mechanism involving synergistic activation by nuclear factor-kappa B (NF-kappa B) with estrogen receptor alpha. Interestingly, we observed that only estrogen receptor-alpha, and not -beta, was able to mediate this effect of estrogens. The partial antiestrogen, 4-hydroxytamoxifen, had the same effect as estrogen. In addition, mutation analysis showed that both the transactivation function of p65 and activation function 1 of estrogen receptor-alpha were essential for this synergistic regulation. Therefore, we propose that NF-kappa B complexes cooperate with estrogen receptor-alpha to recruit cofactors into the complex and thereby synergistically activate the serotonin-1A receptor promoter through nonclassical estrogen response elements by a mechanism that does not involve direct receptor binding to DNA.
65 citations
TL;DR: Three cloned hybridoma cell lines that produce monoclonal antibodies specific for the hormone-binding domain of human ERbeta are cloned and reveal nuclear-specific localization of the ERbeta protein in granulosa cells of the rat ovary and the utility of these antibodies for detection of ERbeta in the human and in several other mammalian species.
TL;DR: 3-alkyl-2,4,5-triarylfurans with basic side-chain substituents were prepared as ligands for the estrogen receptor and those analogues having the basic side chain on the C(4) phenol were high-affinity, ERalpha-selective antagonists.
TL;DR: In best cases, the new interaction is sufficiently favorable and orthogonal so as to represent the creation of a new hormone specificity, which might be useful in the regulation of transgene activity.
TL;DR: Prothymosin α (PTα), a protein associated with cell proliferation and chromatin remodeling, and found to selectively enhance ER transcriptional activity by interacting with a repressor of ER activity, is shown to be a primary response gene to estrogen.
Abstract: Prothymosin α (PTα), a protein associated with cell proliferation and chromatin remodeling, and found to selectively enhance ER transcriptional activity by interacting with a repressor of ER activity, is shown to be a primary response gene to estrogen. Prothymosin α mRNA was rapidly increased by estrogen, followed by a 6-fold increase in prothymosin α protein content in ER-containing breast cancer cells. Analysis of the prothymosin α promoter and 5′-flanking region, and electrophoretic gel mobility shift studies showed the strong inducibility by the estradiol-ER complex to be mediated by two consensus half-palindromic estrogen response elements at −750 and −1051, which directly bind the ER. Estrogenic stimulation of prothymosin α required a DNA binding form of ER with a functional activation function-2 domain. The prothymosin α 5′-regulatory region also contains multiple Sp1 sites. Although addition of Sp1 did not further enhance estradiol-ER stimulated prothymosin α transcriptional activity in breast can...