Mechanisms of action and cross-talk between estrogen receptor and progesterone receptor pathways

Clinical trial-identified inflammatory biomarkers in breast and pancreatic cancers

Breast cancer and pancreatic cancer are two common cancer types characterized by high prevalence and high mortality rates, respectively. However, breast cancer has been more well-studied than pancreatic cancer. This narrative review curated inflammation-associated biomarkers from clinical studies that were systematically selected for both breast and pancreatic cancers and discusses some of the common and unique elements between the two endocrine-regulated malignant diseases. Finding common ground between the two cancer types and specifically analyzing breast cancer study results, we hoped to explore potential feasible methods and biomarkers that may be useful also in diagnosing and treating pancreatic cancer. A PubMed MEDLINE search was used to identify articles that were published between 2015-2022 of different kinds of clinical trials that measured immune-modulatory biomarkers and biomarker changes of inflammation defined in diagnosis and treatment of breast cancer and pancreatic cancer patients. A total of 105 papers (pancreatic cancer 23, breast cancer 82) were input into Covidence for the title and abstract screening. The final number of articles included in this review was 73 (pancreatic cancer 19, breast cancer 54). The results showed some of the frequently cited inflammatory biomarkers for breast and pancreatic cancers included IL-6, IL-8, CCL2, CD8+ T cells and VEGF. Regarding unique markers, CA15-3 and TNF-alpha were two of several breast cancer-specific, and CA19 and IL-18 were pancreatic cancer-specific. Moreover, we discussed leptin and MMPs as emerging biomarker targets with potential use for managing pancreatic cancer based on breast cancer studies in the future, based on inflammatory mechanisms. Overall, the similarity in how both types of cancers respond to or result in further disruptive inflammatory signaling, and that point to a list of markers that have been shown useful in diagnosis and/or treatment method response or efficacy in managing breast cancer could potentially provide insights into developing the same or more useful diagnostic and treatment measurement inflammatory biomarkers for pancreatic cancer. More research is needed to investigate the relationship and associated inflammatory markers between the similar immune-associated biological mechanisms that contribute to breast and pancreatic cancer etiology, drive disease progression or that impact treatment response and reflect survival outcomes.

Progestin Significantly Inhibits Carcinogenesis in the Mogp-TAg Transgenic Mouse Model of Fallopian Tube Cancer

Recent studies suggest that the fallopian tube epithelium (FTE) harbors the precursor for high grade ovarian cancer, creating opportunities for targeting the FTE for ovarian cancer prevention. Preclinical evidence supports progestins as ovarian cancer preventives, but the effect of progestins on the FTE is not well characterized. The murine oviduct-specific glycoprotein promotor-driven simian virus 40 large T-Antigen (mogp-TAg) transgenic mouse model develops neoplastic lesions in the fallopian tube (FT) in a manner similar to that described in human fallopian and ovarian cancer. In this study, we investigated the inhibitory effects of the progestin Depo-medroxyprogesterone acetate (DMPA) on FT carcinogenesis following treatment for 3 and 7 weeks in 5-week-old mogp-TAg mice. Overall, compared to vehicle-treated mice, the FT of DMPA-treated mice was significantly smaller (p<0.0005), accumulated fewer p53-positive cells, had normal distribution of ciliated cells, less nuclear pleomorphism and epithelial tufting, and had a significantly lower proliferative index (p=0.001). Accumulation of p53 signatures and serous tubal intraepithelial carcinomas (STICs) in the FT was significantly reduced in the DMPA (p<0.0005) treatment group. Moreover, the FT of the DMPA-treated mice developed significantly less adenocarcinoma compared to vehicle (p<0.005) at both treatment time points. DMPA treatment significantly induced cleaved caspase-3 (p<0.0005) in the FTE compared to vehicle suggesting that apoptosis is involved in DMPA-related clearance of abnormal cells from the FT. These data demonstrate that DMPA targets early events in FT carcinogenesis by clearing genetically damaged cells, leading to marked reduction in adenocarcinoma, supporting progestins as chemopreventives for FT and ovarian cancer.

Nuclear receptor crosstalk - defining the mechanisms for therapeutic innovation

Nuclear receptor crosstalk can be defined as the interplay between different nuclear receptors or between their overlapping signalling pathways. A subset of nuclear receptors (such as PPARs and RARs) engage in the formation of well-characterized 'typical' heterodimers with RXR. 'Atypical' heterodimers (such as GR with PPARs, or PPAR with ERR) might form a novel class of physical complexes that might be more transient in nature. These heterodimers might harbour strong transcriptional flexibility, with no strict need for DNA binding of both partners. Direct crosstalk could stem from a pairwise physical association between atypical nuclear receptor heterodimers, either via pre-existing interaction pairs or via interactions that are newly induced with small molecules; such crosstalk might constitute an uncharted space to target nuclear receptor physiological and/or pathophysiological actions. In this Review, we discuss the emerging aspects of crosstalk in the nuclear receptor field and present various mechanistic crosstalk modes with examples that support applicability of the atypical heterodimer concept. Stabilization or disruption, in a context-dependent or cell type-dependent manner, of these more transient heterodimers is expected to fuel unprecedented translational approaches to yield novel therapeutic agents to treat major human diseases with higher precision.

Fundamental Frequency Variations Across the Menstrual Cycle and the Use of an Oral Contraceptive Pill

Purpose Concentrations of sex steroid hormones-estrogens, progesterone, and testosterone-have been associated with premenstrual and menstrual vocal symptoms. However, the extent to which these symptoms may be reflected on acoustical features of the voice is still debated. This study investigates variations in fundamental frequency (f _o) and related parameters in connected speech across phases of the menstrual cycle and during the use of a combined oral contraceptive pill (OCP). Method Electrolaryngographic recordings were made, and blood samples were collected at three different phases of the menstrual cycle-menstrual, follicular, and luteal-for placebo and OCP use. These two conditions were blindly and randomly allocated in the study. Speaking f _o (SFF), SFF standard deviation, SFF rate of change, SFF slope, maximum and minimum f _o, and f _o range were extracted for nine healthy females while reading a phrase from the Rainbow Passage. Concentrations of sex hormones were analyzed in serum. Nonparametric statistical tests were carried out to assess differences between phases and conditions. Results SFF, its standard deviation, and maximum f _o were significantly different between phases of the menstrual cycle for placebo use only. Menstrual phase showed the lowest values. Maximum and minimum f _o were significantly different between placebo and OCP use for menstrual and follicular phases, respectively. Conclusions Fluctuations in sex steroid hormones across the menstrual cycle alter f _o in speech more than a particular hormonal concentration. OCP use seems to have a stabilizing effect on the voice relative to f _o and related parameters in speech.

Sex, Gender, and Sex Hormones in Pulmonary Hypertension and Right Ventricular Failure

Pulmonary hypertension (PH) encompasses a syndrome of diseases that are characterized by elevated pulmonary artery pressure and pulmonary vascular remodeling and that frequently lead to right ventricular (RV) failure and death. Several types of PH exhibit sexually dimorphic features in disease penetrance, presentation, and progression. Most sexually dimorphic features in PH have been described in pulmonary arterial hypertension (PAH), a devastating and progressive pulmonary vasculopathy with a 3-year survival rate <60%. While patient registries show that women are more susceptible to development of PAH, female PAH patients display better RV function and increased survival compared to their male counterparts, a phenomenon referred to as the "estrogen paradox" or "estrogen puzzle" of PAH. Recent advances in the field have demonstrated that multiple sex hormones, receptors, and metabolites play a role in the estrogen puzzle and that the effects of hormone signaling may be time and compartment specific. While the underlying physiological mechanisms are complex, unraveling the estrogen puzzle may reveal novel therapeutic strategies to treat and reverse the effects of PAH/PH. In this article, we (i) review PH classification and pathophysiology; (ii) discuss sex/gender differences observed in patients and animal models; (iii) review sex hormone synthesis and metabolism; (iv) review in detail the scientific literature of sex hormone signaling in PAH/PH, particularly estrogen-, testosterone-, progesterone-, and dehydroepiandrosterone (DHEA)-mediated effects in the pulmonary vasculature and RV; (v) discuss hormone-independent variables contributing to sexually dimorphic disease presentation; and (vi) identify knowledge gaps and pathways forward. © 2020 American Physiological Society. Compr Physiol 10:125-170, 2020.

Use of contraceptive depot medroxyprogesterone acetate is associated with impaired cervicovaginal mucosal integrity

BACKGROUND

Injectable depot medroxyprogesterone acetate (DMPA) is one of the most popular contraception methods in areas of high HIV seroprevalence. Evidence is accumulating that use of DMPA might be associated with an increased risk of HIV-1 acquisition by women; however, mechanisms of this association are not completely understood. The goal of this study was to gain insight into mechanisms underlying the possible link between use of DMPA and risk of HIV-1 acquisition, exploring transcription profiling of ectocervical tissues.

METHODS

Healthy women received either DMPA (n = 31) or combined oral contraceptive (COC), which has not been linked to an increased risk of HIV acquisition (n = 32). We conducted a comparative microarray-based whole-genome transcriptome profiling of human ectocervical tissues before and after 6 weeks of hormonal contraception use.

RESULTS

The analysis identified that expression of 235 and 76 genes was significantly altered after DMPA and COC use, respectively. The most striking effect of DMPA, but not COC, was significantly altered expression (mostly downregulation) of many genes strategically involved in the maintenance of mucosal barrier function; the alterations, as indicated by Ingenuity Pathway Analysis (IPA), were most likely due to the DMPA-induced estrogen deficiency. Furthermore, IPA predicted that transcriptome alterations related to ectocervical immune responses were in general compatible with an immunosuppressive effect of DMPA, but, in some women, also with an inflammatory-like response.

CONCLUSION

Our results suggest that impairment of cervicovaginal mucosal integrity in response to DMPA administration is an important mechanism contributing to the potential increased risk of HIV-1 acquisition in DMPA users.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01421368.

FUNDING

This study was supported by the United States Agency for International Development (USAID) under Cooperative Agreement GPO-A-00-08-00005-00.

Association of perceived tinnitus with duration of hormone replacement therapy in Korean postmenopausal women: a cross-sectional study

OBJECTIVE

The purpose of this study was to determine the relationship between hormone replacement therapy (HRT) and tinnitus in South Korea using data from the Korea National Health and Nutrition Examination Surveys (KNHANES) (2010-2012).

STUDY DESIGN

Cross-sectional analysis of a nationwide health survey.

METHODS

KNHANES is a nationally representative cross-sectional survey of South Korea population. Only postmenopausal women aged 19-65 years were included in the study (n=2736). Auditory function was evaluated using pure-tone audiometric testing according to established KNHANES protocols. Subjects were questioned about their experience with tinnitus. Exogenous hormone-related factors included the starting age and duration of HRT.

RESULTS

The overall prevalence of tinnitus was 22.2% among postmenopausal women. (1) Tinnitus severity was significantly higher in women using HRT (p=0.0024) and (2) significantly lower in women who breast fed their children (p=0.0386). (3) According to logistic regression models, the longer duration of HRT was significantly associated with increasing tinnitus (OR=1.323, 95% CI 1.007 to 1.737, p=0.0441).

CONCLUSION

A longer duration of HRT was associated with developing tinnitus in Korean postmenopausal women. Further experimental and epidemiological researches are needed to elucidate the causal relationship between HRT and tinnitus.

Modulation of Progesterone Receptor Isoform Expression in Pregnant Human Myometrium

Background. Regulation of myometrial progesterone receptor (PR) expression is an unresolved issue central to understanding the mechanism of functional progesterone withdrawal and initiation of labor in women. Objectives. To determine whether pregnant human myometrium undergoes culture-induced changes in PR isoform expression ex situ and, further, to determine if conditions approaching the in vivo environment stabilise PR isoform expression in culture. Methods. Term nonlaboring human myometrial tissues were cultured under specific conditions: serum supplementation, steroids, stretch, cAMP, PMA, PGF_2α , NF-κB inhibitors, or TSA. Following 48 h culture, PR-T, PR-A, and PR-B mRNA levels were determined using qRT-PCR. PR-A/PR-B ratios were calculated. Results. PR-T and PR-A expression and the PR-A/PR-B ratio significantly increased in culture. Steroids prevented the culture-induced increase in PR-T and PR-A expression. Stretch blocked the effects of steroids on PR-T and PR-A expression. PMA further increased the PR-A/PR-B ratio, while TSA blocked culture-induced increases of PR-A expression and the PR-A/PR-B ratio. Conclusion. Human myometrial tissue in culture undergoes changes in PR gene expression consistent with transition toward a laboring phenotype. TSA maintained the nonlaboring PR isoform expression pattern. This suggests that preserving histone and/or nonhistone protein acetylation is critical for maintaining the progesterone dependent quiescent phenotype of human myometrium in culture.

Effects of Long-Term Treatment with Estradiol and Estrogen Receptor Subtype Agonists on Serotonergic Function in Ovariectomized Rats

Acute estradiol treatment was reported to slow the clearance of serotonin via activation of estrogen receptors (ER)β and/or GPR30 and to block the ability of a selective serotonin reuptake inhibitor (SSRI) to slow serotonin clearance via activation of ERα. In this study, the behavioral consequences of longer-term treatments with estradiol or ER subtype-selective agonists and/or an SSRI were examined in the forced swim test (FST). Ovariectomized rats were administered the following for 2 weeks: estradiol, ERβ agonist (diarylpropionitrile, DPN), GPR30 agonist (G1), ERα agonist (PPT), and/or the SSRI sertraline. Similar to sertraline, longer-term treatment with estradiol, DPN or G1 induced an antidepressant-like effect. By contrast, PPT did not, even though it blocked the antidepressant-like effect of sertraline. Uterus weights, used as a peripheral measure of estrogenic activity, were increased by estradiol and PPT but not DPN or G1 treatment. A second part of this study investigated, using Western blot analyses in homogenates from hippocampus, whether these behavioral effects are accompanied by changes in the activation of specific signaling pathways and/or TrkB. Estradiol and G1 increased phosphorylation of Akt, ERK and TrkB. These effects were similar to those obtained after treatment with sertraline. Treatment with DPN increased phosphorylation of ERK and TrkB, but it did not alter that of Akt. Treatment with PPT increased phosphorylation of Akt and ERK without altering that of TrkB. In conclusion, activation of at least TrkB and possibly ERK may be involved in the antidepressant-like effect of estradiol, ERβ and GPR30 agonists whereas Akt activation may not be necessary.

Research Resource: STR DNA profile and gene expression comparisons of human BG-1 cells and a BG-1/MCF-7 clonal variant

Human ovarian cancer BG-1 cells are a valuable in vitro model that has enabled several laboratories to study the estrogenic responses of ovarian cancers. We recently discovered that there are two different BG-1 cell lines being used for experiments, denoted here as BG-1 FR and BG-1 NIEHS, which exhibit striking morphological differences. The objective of this study was to methodically analyze these two BG-1 variants and compare their characteristics. Short tandem repeat analysis revealed that the DNA profile of BG-1 FR cells was unique, yet the Short tandem repeat pattern of BG-1 NIEHS was identical with that of MCF-7 cells. From a cytogenetic analysis, it became apparent that the BG-1 FR line had the same profile as previously reported, whereas the BG-1 NIEHS and MCF-7 cells share a similar genetic display. A significant number of unique chromosomal translocations were observed between the BG-1 NIEHS and MCF-7 cells, suggesting that acquired genotypic differences resulted in the formation of two lines from a common origin. Although all cell types demonstrated a similar estrogen responsiveness in reporter gene assays, a microarray analysis revealed distinct estrogen-responsive gene expression patterns with surprisingly moderate to low overlap. We conclude that BG-1 FR is the original ovarian cancer cell line, whereas the BG-1 NIEHS is a variant from the MCF-7 cells. These findings provide much needed clarification of the identities and characteristics of key cell line models that are widely used to study estrogen action in female reproductive cancers.

Damaging effects of multi-walled carbon nanotubes on pregnant mice with different pregnancy times

The mechanism by which nanoparticles cross the placental barrier was studied by using isotopic tracers. The abortion rates and other related data were counted and analysed in pregnant mice with different pregnancy times. Results showed that oxidised multi-walled carbon nanotubes (oMWCNTs) crossed the placental barrier and entered the foetus body. The abortion rates in the pregnant mice depended on pregnancy times. The abortion rates in the first-time, second-time and fourth-time pregnant mice were 70%, 40% and 50%, respectively. The maternal body weight gain was inhibited until gestational ages of 13, 10 and 11 d. oMWCNTs decreased the serum progesterone level and increased the serum oestradiol level in a dose- and time-dependent manner. However, this effect decreased with gestational age. The histology and vascular endothelial growth factor/reactive oxygen species content in the placenta showed that oMWCNTs narrowed the blood vessel and decreased the number of blood vessels in the placenta.

Toxicity and adverse effects of Tamoxifen and other anti-estrogen drugs

Breast cancer is a heterogeneous disease affecting thousands of people every year. Multiple factors are responsible in causing breast cancer while a number of treatment options are also available for the disease. Tamoxifen is the most widely used anti-estrogen for the treatment of hormone-dependent breast cancer. The specific drug is used as a hormonal therapy for patients who exhibit estrogen receptor positive breast cancer. The pharmacological activity of Tamoxifen is dependent on its conversion to its active metabolite, endoxifen, by CYP2D6. Tamoxifen reduces the risk of recurrence and death from breast cancer when given as adjuvant therapy and provides effective palliation for patients with metastatic breast cancer. In this review we focus on the role of Tamoxifen in breast cancer treatment including mechanisms and side-effects. Finally, we discuss in detail the exciting prospects that lie ahead.

Endocrine-Disrupting Chemicals (EDCs): In Vitro Mechanism of Estrogenic Activation and Differential Effects on ER Target Genes

BACKGROUND

Endocrine-disrupting chemicals (EDCs) influence the activity of estrogen receptors (ERs) and alter the function of the endocrine system. However, the diversity of EDC effects and mechanisms of action are poorly understood.

OBJECTIVES

We examined the agonistic activity of EDCs through ERα and ERβ. We also investigated the effects of EDCs on ER-mediated target genes.

METHODS

HepG2 and HeLa cells were used to determine the agonistic activity of EDCs on ERα and ERβ via the luciferase reporter assay. Ishikawa cells stably expressing ERα were used to determine changes in endogenous ER target gene expression by EDCs.

RESULTS

Twelve EDCs were categorized into three groups on the basis of product class and similarity of chemical structure. As shown by luciferase reporter analysis, the EDCs act as ER agonists in a cell type- and promoter-specific manner. Bisphenol A, bisphenol AF, and 2-2-bis(p-hydroxyphenyl)-1,1,1-trichloroethane (group 1) strongly activated ERα estrogen responsive element (ERE)-mediated responses. Daidzein, genistein, kaempferol, and coumestrol (group 2) activated both ERα and ERβ ERE-mediated activities. Endosulfan and kepone (group 3) weakly activated ERα. Only a few EDCs significantly activated the "tethered" mechanism via ERα or ERβ. Results of real-time polymerase chain reaction indicated that bisphenol A and bisphenol AF consistently activated endogenous ER target genes, but the activities of other EDCs on changes of ER target gene expression were compound specific.

CONCLUSION

Although EDCs with similar chemical structures (in the same group) tended to have comparable ERα and ERβ ERE-mediated activities, similar chemical structure did not correlate with previously reported ligand binding affinities of the EDCs. Using ERα-stable cells, we observed that EDCs differentially induced activity of endogenous ER target genes.

Effect of progesterone receptor status on maspin synthesis via nitric oxide production in neutrophils in human breast cancer

BACKGROUND

Although progesterone receptor (PR) status, similarly to estrogen receptor status, is of prognostic importance in breast cancer, the involvement of the PR in breast cancer remains obscure. Studies were conducted to determine the function of the PR in neutrophils in the nitric oxide-induced synthesis of maspin, an anti-breast-cancer protein produced in nonmalignant mammary cells and in neutrophils in the circulation.

METHODS

PR status was determined by immunohistochemistry. Maspin synthesis was determined by in-vitro translation of messenger RNA and quantified by enzyme-linked immunosorbent assay. Nitric oxide was determined by the methemoglobin method.

RESULTS

It was found that PR status in neutrophils was identical with that in malignant breast tissues. A Scatchard plot for progesterone binding to normal and PR-positive (PR+) neutrophils revealed that whereas normal neutrophils had 11.5 × 10(10) PR sites/cell with K d = 47.619 nM, PR+ neutrophils had 6.6 × 10(10) PR sites/cell with K d = 47.619 nM. The progesterone negative (PR-) neutrophils failed to bind to progesterone. Incubation of normal and PR+ neutrophils with 25 nM progesterone produced 1.317 μM NO and 2.329 nM maspin; the PR+ neutrophils produced 0.72 μM NO and 1.138 nM maspin. The PR- neutrophils failed to produce any NO or maspin in the presence of progesterone. Inhibition of progesterone-induced NO synthesis led to complete inhibition of maspin synthesis in all neutrophils.

CONCLUSION

These results suggest that estrogen and progesterone complement each other in NO-induced maspin synthesis, and do not necessarily antagonize in the synthesis of the anti-breast-cancer protein.

Comparison of the effects of estradiol and progesterone on serotonergic function

BACKGROUND

Ovarian hormones may contribute to the vulnerability to depression, as well as to the response to antidepressants (ADs). Previously, we reported that acute systemic treatment with estradiol or progesterone blocked the ability of the selective serotonin reuptake inhibitor, fluvoxamine, to inhibit serotonin transporter function in ovariectomized rats. In this study, behavioral consequences, as well as receptor mechanisms underlying these hormonal effects, were investigated.

METHODS

Using the forced swimming test, the acute effect of estradiol and/or progesterone on fluvoxamine's AD-like effects was investigated. Using in vivo chronoamperometry, the effect of local application of estradiol or progesterone into the hippocampus of ovariectomized rats on serotonin (5-HT) clearance, as well as on the ability of fluvoxamine to slow 5-HT clearance, were investigated.

RESULTS

The decreased immobility and increased swimming caused by fluvoxamine in the forced swimming test was blocked in rats treated with estradiol and/or progesterone. Local application of estradiol, but not progesterone, slowed 5-HT clearance and both hormones blocked the ability of fluvoxamine to slow 5-HT clearance. Use of hormone receptor agonists and antagonists, revealed that the effects of estradiol are mediated by activation of membrane, as well as nuclear estrogen receptors (ER). The AD-like effect of estradiol involved ER beta and G-protein coupled receptor 30, whereas its blockade of fluvoxamine's effects was ER alpha-mediated. The effects of progesterone occurred solely by activation of intracellular progesterone receptors.

CONCLUSIONS

Targeting of ER beta or G-protein coupled receptor 30 might reveal a strategy to permit beneficial effects of estrogen without its deleterious effect on selective serotonin reuptake inhibitor efficacy.

Distribution of estrogen receptor α and progesterone receptor B in the bovine oviduct during the follicular and luteal phases of the sexual cycle: an immunohistochemical and semi-quantitative study

The aim of our study was to determine the distribution of estrogen receptor α (ERα) and progesterone receptor B (PR-B) in the bovine oviduct during the follicular and luteal phases. Bovine oviducts from 23 animals were obtained from a local slaughterhouse. Blood samples from these animals also were taken before death to measure estrogen and progesterone levels. The serum levels of estradiol-17β and progesterone changed during the estrous cycle. Tissue distribution of ERα and PR-B was examined using immunohistochemical techniques and the results showed that ERα and PR-B were stained in nuclei of cells and could be detected in all compartments along the entire oviduct during both the follicular and luteal phases. During the follicular phase, no significant differences were found between ERα and PR-B distribution (p < 0.05), while significant differences were found between ERα and PR-B during the luteal phase (p < 0.05). We results indicated that the frequency and intensity of ERα and PR-β immunoreactivity in the oviduct of bovines varied according to the oviductal cell types and the phases of the sexual cycle.

Role of G protein-coupled estrogen receptor 1, GPER, in inhibition of oocyte maturation by endogenous estrogens in zebrafish

Estrogen inhibition of oocyte maturation (OM) and the role of GPER (formerly known as GPR30) were investigated in zebrafish. Estradiol-17beta (E2) and G-1, a GPER-selective agonist, bound to zebrafish oocyte membranes suggesting the presence of GPER which was confirmed by immunocytochemistry using a specific GPER antibody. Incubation of follicle-enclosed oocytes with an aromatase inhibitor, ATD, and enzymatic and manual removal of the ovarian follicle cell layers significantly increased spontaneous OM which was partially reversed by co-treatment with either 100 nM E2 or G-1. Incubation of denuded oocytes with the GPER antibody blocked the inhibitory effects of estrogens on OM, whereas microinjection of estrogen receptor alpha (ERalpha) antisense oligonucleotides into the oocytes was ineffective. The results suggest that endogenous estrogens produced by the follicle cells inhibit or delay spontaneous maturation of zebrafish oocytes and that this estrogen action is mediated through GPER. Treatment with E2 and G-1 also attenuated the stimulatory effect of the teleost maturation-inducing steroid, 17,20beta-dihyroxy-4-pregnen-3-one (DHP), on OM. Moreover, E2 and G-1 down-regulated the expression of membrane progestin receptor alpha (mPRalpha), the intermediary in DHP induction of OM. Conversely DHP treatment caused a >50% decline in GPER mRNA levels. The results suggest that estrogens and GPER are critical components of the endocrine system controlling the onset of OM in zebrafish. A model is proposed for the dual control of the onset of oocyte maturation in teleosts by estrogens and progestins acting through GPER and mPRalpha, respectively, at different stages of oocyte development.

Microsomal epoxide hydrolase expression in the endometrial uterine corpus is regulated by progesterone during the menstrual cycle

We have shown previously that high expression levels of microsomal epoxide hydrolase (mEH) correlate with a poor prognosis of breast cancer patients receiving tamoxifen, suggesting that enhanced mEH expression could lead to antiestrogen resistance (Fritz et al. in J Clin Oncol 19:3-9, 2001). Thus, the purpose of this study was to gain insights into the role of mEH in hormone-responsive tissues. We analyzed biopsy samples of the endometrium by immunohistochemical staining, pointing to a regulation of mEH during the menstrual cycle: during the first half mEH expression was low, increased during the second half and reached highest levels during pregnancy. Additionally, the progesterone receptor (PR) positive human endometrial cell lines IKPRAB-36 (estrogene receptor alpha [ERalpha] negative) and ECC1-PRAB72 (ERalpha positive) were chosen to further investigate the hormonal regulation of mEH expression. Western Blot and quantitative RT-PCR analysis revealed an increase of mEH expression after treatment with medroxy-progesterone 17-acetate (MPA) in the ERalpha containing ECC1-PRAB72 cells. In contrast our results suggest that MPA had no influence on the mEH protein level in the ERalpha- IKPRAB-36 cells. In conclusion, mEH expression is regulated by progesterone in the presence of both PRs and ERalpha.

Estrogen and progesterone receptors have distinct roles in the establishment of the hyperplastic phenotype in PR-A transgenic mice

Introduction

Expression of the A and B forms of progesterone receptor (PR) in an appropriate ratio is critical for mammary development. Mammary glands of PR-A transgenic mice, carrying an additional A form of PR as a transgene, exhibit morphological features associated with the development of mammary tumors. Our objective was to determine the roles of estrogen (E) and progesterone (P) in the genesis of mammary hyperplasias/preneoplasias in PR-A transgenics.

Methods

We subjected PR-A mice to hormonal treatments and analyzed mammary glands for the presence of hyperplasias and used BrdU incorporation to measure proliferation. Quantitative image analysis was carried out to compare levels of latency-associated peptide and transforming growth factor beta 1 (TGFβ1) between PR-A and PR-B transgenics. Basement membrane disruption was examined by immunofluorescence and proteolytic activity by zymography.

Results

The hyperplastic phenotype of PR-A transgenics is inhibited by ovariectomy, and is reversed by treatment with E + P. Studies using the antiestrogen ICI 182,780 or antiprogestins RU486 or ZK 98,299 show that the increase in proliferation requires signaling through E/estrogen receptor alpha but is not sufficient to give rise to hyperplasias, whereas signaling through P/PR has little impact on proliferation but is essential for the manifestation of hyperplasias. Increased proliferation is correlated with decreased TGFβ1 activation in the PR-A transgenics. Analysis of basement membrane integrity showed loss of laminin-5, collagen III and collagen IV in mammary glands of PR-A mice, which is restored by ovariectomy. Examination of matrix metalloproteases (MMPs) showed that total levels of MMP-2 correlate with the steady-state levels of PR, and that areas of laminin-5 loss coincide with those of activation of MMP-2 in PR-A transgenics. Activation of MMP-2 is dependent on treatment with E and P in ovariectomized wild-type mice, but is achieved only by treatment with P in PR-A mice.

Conclusions

These data establish a link between hormonal response, proliferation, modulation of MMP activity and maintenance of basement membrane integrity that depend on a balance in the expression levels of PR-A and PR-B isoforms. Notably, concomitant increased proliferation, due to inhibition of TGFβ1 activation, and loss of basement membrane integrity, via increased MMP-2 activity, appear to be prerequisites for the PR-A hyperplastic phenotype.

Neisseria gonorrhoeae survival during primary human cervical epithelial cell infection requires nitric oxide and is augmented by progesterone

Neisseria gonorrhoeae is an obligate human pathogen that causes gonorrhea. We have shown previously that complement receptor 3 and Akt kinase play important roles in mediating cervical infection. At present, there are limited data to indicate how hormonally induced changes to the mucosal epithelia of the female genital tract mediate the course of gonococcal disease. Hence, I have expanded upon previous work to investigate the interaction of gonococci with primary human cervical epithelial (pex) cells under the variable estrogen and progesterone concentrations likely to be encountered in vivo throughout the female menstrual cycle. My data indicated that the ability of gonococci to survive and to replicate within pex cells was increased under progesterone-predominant conditions. Using bacterial survival, immunological, and kinase assays, I show that progesterone functioned in an additive manner with gonococcal phospholipase D to augment Akt kinase activity. This, in turn, resulted in a parallel increase in nitric oxide synthase expression. Nitric oxide production by pex cells was dependent upon Akt activity and was increased under progesterone-predominant conditions. Whereas both inducible and endothelial nitric oxide synthase contributed to nitric oxide production, only inducible nitric oxide synthase activity promoted gonococcal survival within pex cells. Collectively, these data provide the first clues as to how steroid hormones potentially modulate the course of gonococcal disease in women. In addition, these data demonstrate that host-derived nitric oxide likely is not protective against gonococci, in vivo; rather, nitric oxide may be required to sustain cervical bacterial disease.

The potential biomarkers in predicting pathologic response of breast cancer to three different chemotherapy regimens: a case control study

Background

Preoperative chemotherapy (PCT) has become the standard of care in locally advanced breast cancer. The identification of patient-specific tumor characteristics that can improve the ability to predict response to therapy would help optimize treatment, improve treatment outcomes, and avoid unnecessary exposure to potential toxicities. This study is to determine whether selected biomarkers could predict pathologic response (PR) of breast tumors to three different PCT regimens, and to identify a subset of patients who would benefit from a given type of treatment.

Methods

118 patients with primary breast tumor were identified and three PCT regimens including DEC (docetaxel+epirubicin+cyclophosphamide), VFC (vinorelbine/vincristine+5-fluorouracil+cyclophosphamide) and EFC (epirubicin+5-fluorouracil+cyclophosphamide) were investigated. Expression of steroid receptors, HER2, P-gp, MRP, GST-pi and Topo-II was evaluated by immunohistochemical scoring on tumor tissues obtained before and after PCT. The PR of breast carcinoma was graded according to Sataloff's classification. Chi square test, logistic regression and Cochran-Mantel-Haenszel assay were performed to determine the association between biomarkers and PR, as well as the effectiveness of each regimen on induction of PR.

Results

There was a clear-cut correlation between the expression of ER and decreased PR to PCT in all three different regimens (p < 0.05). HER2 expression is significantly associated with increased PR in DEC regimen (p < 0.05), but not predictive for PR in EFC and VFC groups. No significant correlation was found between biomarkers PgR, Topo-II, P-gp, MRP or GST-pi and PR to any tested PCT regimen. After adjusted by a stratification variable of ER or HER2, DEC regimen was more effective in inducing PR in comparison with VFC and EFC regimens.

Conclusion

ER is an independent predictive factor for PR to PCT regimens including DEC, VFC and EFC in primary breast tumors, while HER2 is only predictive for DEC regimen. Expression of PgR, Topo-II, P-gp, MRP and GST-pi are not predictive for PR to any PCT regimens investigated. Results obtained in this clinical study may be helpful for the selection of appropriate treatments for breast cancer patients.

Identification of a regulatory loop for the synthesis of neurosteroids: a steroidogenic acute regulatory protein-dependent mechanism involving hypothalamic-pituitary-gonadal axis receptors

Brain sex steroids are derived from both peripheral (primarily gonadal) and local (neurosteroids) sources and are crucial for neurogenesis, neural differentiation and neural function. The mechanism(s) regulating the production of neurosteroids is not understood. To determine whether hypothalamic-pituitary-gonadal axis components previously detected in the extra-hypothalamic brain comprise a feedback loop to regulate neuro-sex steroid (NSS) production, we assessed dynamic changes in expression patterns of steroidogenic acute regulatory (StAR) protein, a key regulator of steroidogenesis, and key hypothalamic-pituitary-gonadal endocrine receptors, by modulating peripheral sex hormone levels in female mice. Ovariectomy (OVX; high serum gonadotropins, low serum sex steroids) had a differential effect on StAR protein levels in the extrahypothalamic brain; increasing the 30- and 32-kDa variants but decreasing the 37-kDa variant and is indicative of cholesterol transport into mitochondria for steroidogenesis. Treatment of OVX animals with E(2), P(4), or E(2) + P(4) for 3 days, which decreases OVX-induced increases in GnRH/gonadotropin production, reversed this pattern. Suppression of gonadotropin levels in OVX mice using the GnRH agonist leuprolide acetate inhibited the processing of the 37-kDa StAR protein into the 30-kDa StAR protein, confirming that the differential processing of brain StAR protein is regulated by gonadotropins. OVX dramatically suppressed extra-hypothalamic brain gonadotropin-releasing hormone 1 receptor expression, and was further suppressed in E(2)- or P(4)-treated OVX mice. Together, these data indicate the existence of endocrine and autocrine/paracrine feedback loops that regulate NSS synthesis. Further delineation of these feedback loops that regulate NSS production will aid in developing therapies to maintain brain sex steroid levels and cognition.

Progesterone receptor B recruits a repressor complex to a half-PRE site of the estrogen receptor alpha gene promoter

In the present study, we demonstrate that elevated levels of the progesterone receptor (PR)-B isoform in breast cancer cells induces down-regulation of estrogen receptor (ER) alpha mRNA and protein content, causing concomitant repression of the estrogen-regulated genes insulin receptor substrate 1, cyclin D1, and pS2, addressing a specific effect of PR/PR-B on ERalpha gene transcription. ERalpha gene promoter activity was drastically inhibited by PR-B overexpression. Promoter analysis revealed a transcriptionally responsive region containing a half-progesterone response element (PRE) site located at -1757 bp to -1752 bp. Mutation of the half-PRE down-regulated the effect induced by PR/PR-B overexpression. Moreover chromatin immunoprecipitation analyses revealed an increase of PR bound to the ERalpha-regulatory region encompassing the half-PRE site, and the recruitment of a corepressor complex containing nuclear receptor corepressor (NCoR) but not silencing mediator of retinoid and thyroid hormone receptor and DAX1, concomitantly with hypoacetylation of histone H4 and displacement of RNA polymerase II. Furthermore, NCoR ablation studies demonstrated the crucial involvement of NCoR in the down-regulatory effects due to PR-B overexpression on ERalpha protein and mRNA. We also demonstrated that the ERalpha regulation observed in MCF-7 cells depended on PR-B expression because PR-B knockdown partially abrogates the feedback inhibition of ERalpha levels after estrogenic stimulus. Our study provides evidence for a mechanism by which overexpressed PR-B is able to actively repress ERalpha gene expression.

Estrogen receptor alpha (ERalpha) phospho-serine-118 is highly expressed in human uterine leiomyomas compared to matched myometrium

It is thought that the growth of uterine leiomyomas may be mediated by the interaction of estrogen receptor alpha (ERalpha) and growth factor pathways and that phosphorylation of ERalpha at serine 118 (ERalpha-phospho-Ser118) is important in this interaction. In this study, immunoblotting and immunohistochemistry were used to investigate the expression of ERalpha-phospho-Ser118, phosphorylated p44/42 mitogen-activated protein kinase (phospho-p44/42 MAPK), and proliferating cell nuclear antigen (PCNA) in human leiomyoma and myometrial tissues during the proliferative and secretory phases of the menstrual cycle. We found that tumors taken from the proliferative phase expressed significantly higher levels of ERalpha-phospho-Ser118, phospho-p44/42 MAPK, and PCNA compared to patient-matched myometria and had significantly higher ERalpha-phospho-Ser118 and PCNA expression compared to secretory phase tumors. Also, enhanced colocalization and association of phospho-p44/42 MAPK and ERalpha-phospho-Ser118 were observed in proliferative phase tumors by confocal microscopy and immunoprecipitation, respectively. These data suggest that ERalpha-phospho-Ser118 may be important in leiomyoma growth and is possibly phosphorylated by phospho-p44/42 MAPK.

Krüppel-Like Factor 9 Is a Negative Regulator of Ligand-Dependent Estrogen Receptor α Signaling in Ishikawa Endometrial Adenocarcinoma Cells

Estrogen and progesterone, acting through their respective receptors and other nuclear proteins, exhibit opposing activities in target cells. We previously reported that Krüppel-like factor 9 (KLF9) cooperates with progesterone receptor (PR) to facilitate P-dependent gene transcription in uterine epithelial cells. Here we evaluated whether KLF9 may further support PR function by directly opposing estrogen receptor (ER) signaling. Using human Ishikawa endometrial epithelial cells, we showed that 17β-estradiol (E2)-dependent down-regulation of ERα expression was reversed by a small interfering RNA to KLF9. Transcription assays with the E2-sensitive 4× estrogen-responsive element-thymidine kinase-promoter-luciferase reporter gene demonstrated inhibition of ligand-dependent ERα transactivation with ectopic KLF9 expression. E2 induced PR-A/B and PR-B isoform expression in the absence of effects on KLF9 levels. Addition of KLF9 small interfering RNA augmented E2 induction of PR-A/B while abrogating that of PR-B, indicating selective E2-mediated inhibition of PR-A by KLF9. Chromatin immunoprecipitation of the ERα minimal promoter demonstrated KLF9 promotion of E2-dependent ERα association to a region containing functional GC-rich motifs. KLF9 inhibited the recruitment of the ERα coactivator specificity protein 1 (Sp1) to the PR proximal promoter region containing a half-estrogen responsive element and GC-rich sites, but had no effect on Sp1 association to the PR distal promoter region containing GC-rich sequences. In vivo association of KLF9 and Sp1, but not of ERα with KLF9 or Sp1, was observed in control and E2-treated cells. Our data identify KLF9 as a transcriptional repressor of ERα signaling and suggest that it may function at the node of PR and ER genomic pathways to influence cell proliferation.

Steroid hormone control of myometrial contractility and parturition

The precise temporal control of uterine contractility is essential for the success of pregnancy. For most of pregnancy, progesterone acting through genomic and non-genomic mechanisms promotes myometrial relaxation. At parturition the relaxatory actions of progesterone are nullified and the combined stimulatory actions of estrogens and other factors such as myometrial distention and immune/inflammatory cytokines, transform the myometrium to a highly contractile and excitable state leading to labor and delivery. This review addresses current understanding of how progesterone and estrogens affect the contractility of the pregnancy myometrium and how their actions are coordinated and controlled as part of the parturition cascade.

Effects of the components of hormone therapy on matrix metalloproteinases in breast-cancer cells: an in vitro study

A combination of E and progestogens significantly increased matrix metalloproteinase (MMP)-2 in both T47D cells (E(2)-medroxyprogesteroneacetate [MPA] and E(2)-P) and MCF-7 cells (E(2)-MPA, E(2)-P, and equilin-MPA). All combinations resulted in higher MMP-9 levels in MCF-7 cells, but higher MMP-9 levels resulted only with equilin-norethinderone in T47D cells.

The expression of Hedgehog genes (Ihh, Dhh) and Hedgehog target genes (Ptc1, Gli1, Coup-TfII) is affected by estrogenic stimuli in the uterus of immature female rats

The objective of this study was to investigate the effects of estrogen receptor (ER) agonists and an ER antagonist on the expression of Hedgehog genes (Indian hedgehog: Ihh; Desert hedgehog: Dhh) and Hedgehog target genes (Patched 1: Ptc1; glioma-associated oncogene homolog 1: Gli1; chicken ovalbumin upstream promoter transcription factor II: Coup-TfII) in the rat uterus. Immature female rats were administered once with 17alpha-ethynyl estradiol (EE, an ER agonist), propyl pyrazole triole (PPT, an ERalpha-selective agonist), diarylpropionitrile (DPN, an ERbeta-selective agonist), or ICI 182,780 (an ER antagonist). Expression of mRNA for Ihh, Dhh, and Ptc1 was dose-dependently downregulated by EE in the uterus of immature rats, mediated by ER as confirmed by coadministration of ICI 182,780. The mRNA expression levels of Ptc1, Gli1, and Coup-TfII were simultaneously downregulated during the period in which the mRNA expression levels of Ihh and Dhh were downregulated in the uterus after administration of EE. PPT downregulated the transcription of Ihh, Dhh, Ptc1, Gli1, and Coup-TfII, indicating that expression of these genes was regulated by the ERalpha-dependent pathway. DPN also downregulated the transcription of Ihh and Dhh, although the effect was weaker than that of PPT, indicating that the regulation of uterine Ihh and Dhh transcription was also affected by the ERbeta-dependent pathway. These results suggest that the expression of Hedgehog genes (Ihh, Dhh) and Hedgehog target genes (Ptc1, Gli1, Coup-TfII) is affected by estrogenic stimuli in the uterus of immature female rats.

Genetic Polymorphisms of Estrogen Receptors in Patients with Premature Coronary Artery Disease

BACKGROUND

Estrogen protects against atherosclerosis through its genomic/nongenomic effects. Estrogen receptors (ESR) alpha (1) and beta (2) mediate much estrogen action. Both receptors exist in the arterial wall, but the extent of their distribution in arterial layers is unknown. Allelic variants of the gene encoding ESR1 and ESR2 may alter their expression and function, resulting in genetic variability.

METHODS

In the present age-adjusted, case-control study, the prevalence of four mutations in estrogen receptors was analyzed in patients with premature CAD and controls.

RESULTS

Mutation in the ESR1 (PvuII) was more prevalent in the controls (18 vs. 11%; p=0.062) than in CAD patients, and the mutation identified by the XbaI enzyme in the same receptor was associated with reduced apolipoprotein B levels and low body mass index. Mutation of the ESR2 (AluI) was more prevalent in CAD patients (0.6 vs. 18%; p=0.008). Homozygosis for this mutation involved increased body mass index, elevated serum triglycerides and apolipoprotein B, and reduced HDL-cholesterol. Multivariate logistic regression analysis showed dyslipidemia, low serum HDL levels, and ESR2 polymorphism (AluI) [OR=1.89 (95% CI: 1.08-3.34); p=0.034] to be independent risk factors for CAD.

CONCLUSIONS

Our data suggest that mutation of the ESR2 is an independent risk marker for premature CAD.

Expression of steroid hormone receptors in BRCA1-associated ovarian carcinomas

OBJECTIVE

BRCA1 mutations predispose to cancer in hormone responsive tissues. A predominance of estrogen receptor (ER)-negative breast cancers in BRCA1 mutation carriers and potential interactions between ERalpha and BRCA1 suggest a link between hormones and BRCA1. However, the expression pattern of ERalpha and other hormone receptors in BRCA1-associated ovarian cancer was unknown.

METHODS

Twenty-two BRCA1-associated ovarian cancer cases were matched with sporadic cases (no family history of ovarian or breast cancer) for FIGO stage, grade, histologic subtype, and patient age and hormone receptor expression was measured immunohistochemically.

RESULTS

ERalpha expression was similar in BRCA1-associated ovarian cancer compared with matched sporadic counterparts, in contrast with previous findings in BRCA1-linked breast cancer. There was also no significant difference in expression of progesterone receptors and androgen receptor between the matched cases in the two groups. However, differences were noted in the relative expression of receptor isotypes, in particular, levels of ERalpha and ERbeta were positively correlated in sporadic tumors but inversely related in BRCA1-associated tumors.

CONCLUSION

Similar hormone receptor expression in BRCA1-associated ovarian cancer and matched sporadic counterparts may be further evidence that at least a proportion of sporadic ovarian tumors and BRCA1-associated tumors develop through similar pathways.

Estradiol regulates susceptibility following primary exposure to genital herpes simplex virus type 2, while progesterone induces inflammation

We report here that sex hormones modulate susceptibility to a sexually transmitted viral agent, herpes simplex virus type 2 (HSV-2), in a mouse model. Ovariectomized mice were administered either saline (control), estradiol (E(2)), progesterone (P(4)), or a combination of both estradiol and progesterone (E+P) and infected intravaginally with HSV-2. With an inoculation dose of 10(5) PFU, the saline- and P(4)-treated mice were found to be highly susceptible to genital HSV-2 infection. Both groups had extensive pathology and high viral titers in vaginal secretions, and 100% of mice succumbed by day 4 postinfection. E(2)-treated mice were protected from HSV-2 infection at the same dose and did not display any vaginal pathology or viral shedding. There was a slow progression of genital pathology in the combination hormone-treated group, along with prolonged viral shedding; 80% of animals succumbed by day 13. With lower inoculation doses of 10(3) and 10(2) PFU, 50 and 100%, respectively, of the combination hormone-treated mice survived. Localization of HSV-2 infection showed extensive infection in the vaginal epithelium of P(4)- and saline-treated animals within 24 h of inoculation. E(2)-treated animals were clear of infection, while the E+P-treated group had focal infection at 24 h that had progressed extensively by day 3. Infection was accompanied by persistent inflammation and infiltration of neutrophils in the P(4)-treated group. An analysis of the genes in the vaginal tissue showed that inflammation in the P(4)-treated group correlated with local induction of chemokines and chemokine receptors that were absent in the E(2)-treated mice and in uninfected P(4)-treated mice. The results show that sex hormones regulate initiation of infection and immune responses to genital HSV-2 infection.

Protection against genital herpes infection in mice immunized under different hormonal conditions correlates with induction of vagina-associated lymphoid tissue

The present study was undertaken to examine the effect of the hormonal environment on immunization with an attenuated strain of herpes simplex virus type 2 (HSV-2 TK(-)) and subsequent protection against challenge. Ovariectomized mice were administered saline (S; control), estradiol (E(2)), progesterone (P(4)), or a combination of estradiol and progesterone (E+P) and immunized intravaginally (IVAG) with HSV-2 TK(-). Three weeks later, the immunized mice were challenged IVAG with wild-type HSV-2. Mice that were immunized following E treatment were not protected, whereas complete protection against the challenge was seen in mice from the S- and P(4)-treated groups. In the P(4)-treated group, 15% of mice developed chronic pathology following TK(-) immunization. Interestingly, about 40% of the E+P-treated mice were also protected. Upon examination of viral shedding in the vaginal secretions, it was clear that protection against challenge was dependent on the ability of the TK(-) virus to cause productive genital infection under different hormonal conditions. In the protected mice (the S and P groups and part of the E+P group), induced vagina-associated lymphoid tissues composed of CD11c(+) dendritic cells and CD3(+) and CD4(+) T cells were formed transiently in the vaginal lamina propria from day 2 to day 5 postchallenge. These aggregates were absent in the unprotected mice (the E group and part of the E+P group). Significant HSV-2-specific activation of lymphocytes was observed in the local draining lymph nodes of protected mice. This response was absent in the unprotected groups. High titers of gB-specific local immunoglobulin A (IgA) antibodies were present in the vaginal secretions of S- and P(4)-treated immunized mice following HSV-2 challenge. The S-treated group of mice also had high gB-specific IgG titers. These studies show that sex hormones modify the induction of protective immune responses following IVAG immunization.

Visual sensitivity across the menstrual cycle

This study was designed to evaluate the hypothesis that hormonal change can affect lower level light-adaptation processes, which are likely to be retinally based. Foveal visual sensitivities were measured across several menstrual cycles of four women not using hormonally acting medication and across several menstrual cycles of three women using a triphasic oral contraceptive. One woman, diagnosed with premenstrual syndrome (PMS), was a subject for both groups. Sensitivities were measured for a series of test wavelengths for 580-nm backgrounds of 2.0 and 4.0 log td. Of the six individuals tested, one had clear evidence of visual-adaptation changes occurring in phase with the menstrual cycle. Prior to using the oral contraceptive, this individual (the PMS subject) experienced changes of short-wavelength-sensitive (SWS)-cone-mediated sensitivities of up to about 1.4 log unit on the 4.0 log td background. Her SWS-cone-mediated sensitivities tended to be highest near ovulation and lowest premenstrually. Threshold-versus-illuminance (TVI) curves confirmed that the rate of sensitivity decrease with increasing background illuminance (i.e. the TVI slope) was greater premenstrually. The degree of background-induced desensitization within her middle-wavelength-sensitive (MWS)/long-wavelength-sensitive (LWS) cone pathways also appeared to vary cyclically, but the magnitude of the variation was smaller and the time course appeared to be different. When this subject began oral contraceptive use, the patterns of sensitivity change were all altered. None of the other five subjects experienced changes of SWS-cone-mediated vision that were cyclic and significantly adaptation-state dependent. However, there was evidence for a limited degree of cyclic adaptation change within the MWS/LWS cone pathways of at least one additional subject. We conclude that hormonal change can--for some unknown proportion of women--be linked to alterations of retinal function. However, the alterations are not the same for all visual pathways, and there are pronounced individual differences. The data also demonstrate that individuals' visual adaptation capabilities can vary substantially over periods of weeks.

Gene regulation profile reveals consistent anticancer properties of progesterone in hormone-independent breast cancer cells transfected with progesterone receptor

Absence of estrogen receptor (ER) and progesterone receptor (PR) is the hallmark of most hormone-independent breast cancers. Previous studies demonstrated that reactivation of PR expression in hormone-independent MDA-MB-231 breast cancer cells enabled progesterone to suppress cell growth both in vitro and in vivo. We determined the whole genomic effect of progesterone in PR-transfected MDA-MB-231 cells. We identified 151 progesterone-regulated genes with expression changes > 3-fold after 24 hr treatment. Most are novel progesterone target genes. Real-time RT-PCR analysis of 55 genes showed a 100% confirmation rate. Twenty-six genes were regulated at both 3 and 24 hr. Studies using translation inhibitor suggest that most of the 26 genes are primary progesterone target genes. Progesterone consistently suppressed the expression of genes required for cell proliferation and metastasis and increased the expression of many tumor-suppressor genes. Progesterone also consistently decreased the expression of DNA repair and chromosome maintenance genes, which may be part of the mechanism leading to cell cycle arrest. These data suggest potential usefulness of progestin in combating ER-negative but PR-positive breast cancer and indicate that progesterone can exert a strong anticancer effect in hormone-independent breast cancer following PR reactivation. The identification of many novel progesterone target genes open up new avenues for in-depth elucidation of progesterone-mediated molecular networks.

5-benzylidene-1,2-dihydrochromeno[3,4-f]quinolines as selective progesterone receptor modulators

A series of 5-benylidene-1,2-dihydrochromeno[3,4-f]quinolines (4) were synthesized and tested in bioassays to evaluate their progestational activities, receptor- and tissue-selectivity profiles as selective progesterone receptor modulators (SPRMs). Most of the new analogues exhibited as highly potent progestins with more than 100-fold receptor selectivity over other steroid hormone receptors and LG120920 (7b) demonstrated tissue selectivity toward uterus and vagina versus breasts in a rodent model after oral administration.

Arzoxifene as therapy for endometrial cancer

OBJECTIVE

Arzoxifene, an orally active third-generation selective estrogen-receptor modulator (SERM), opposes the action of estrogen on the breast and endometrium but exerts an estrogen-agonist effect on bone and the lipid profile. Since this is an appealing combination for hormonal therapy of estrogen-related cancers, we initiated testing the potential of arzoxifene in women with treatment-refractory endometrial cancer.

METHODS

Two phase I studies were conducted to evaluate the safety and pharmacokinetics of single and multiple doses of arzoxifene. In addition, two multi-institutional phase II trials have been completed on 100 women with metastatic or recurrent endometrial cancer.

RESULTS

No serious adverse events were observed in the single-dose phase I study, the principal side effect being hot flashes in 5/15 healthy volunteers. In the second phase I study, conducted in 32 women with metastatic breast cancer, one patient had a serious, possibly drug-related adverse reaction (pulmonary embolism). The two multi-institutional trials demonstrated significant activity at 20 mg/day in patients with metastatic or recurrent endometrial cancer. Observed clinical response rates were 25 and 31%, with a median response duration of 19.3 and 13.9 months, respectively. Progression of the disease was stabilized in a substantial number of women. Toxicity was mild, except for two cases of pulmonary embolism that might have been drug related.

CONCLUSIONS

Further investigation is warranted to verify these preliminary response rates and the clinical significance of the stable disease cases, to compare clinical outcomes with those in progestin-treated women, and to elucidate the mechanisms of SERM action in this disease.

Identification of estrogen receptor beta expression in Chinese hamster ovary (CHO) cells and comparison of estrogen-responsive gene transcription in cells adapted to serum-free media

Most cultured cell lines require addition of serum to the medium to maintain their proliferative capacity. For studies examining the cellular effects of estrogens serum is charcoal-stripped to remove steroids. Nonetheless, addition of the selective estrogen receptor modulator (SERM) 4-hydroxytamoxifen (4-OHT) inhibits the basal transcriptional activity of estrogen receptors alpha or beta (ERalpha or ERbeta) in transfected cells. We tested the hypothesis that elimination of serum from the culture medium will block 4-OHT's repression of basal activity. Chinese hamster ovary (CHO-K1) cells adapted to serum-free medium exhibited estrogen responsiveness that was identical with that of the cells grown in serum-containing media. 4-OHT-suppressed basal transcription of an estrogen response element (ERE)-reporter in ERalpha-transfected cells even in the absence of serum, indicating that the 4-OHT suppressive activity is not mediated by blocking ER interaction with serum estrogens. We speculate that 4-OHT-ER recruits co-repressors to suppress basal transcription. We discovered that CHO-K1 cells express ERalpha and ERbeta mRNA. However only ERbeta protein was expressed and use of ERbeta-selective 2,3-bis(4-hydroxy-phenyl)propionitrile (DPN) and ERalpha-selective 4-propyl-1,3,5-tris(4-hydroxy-phenyl)pyrazole) (PPT) revealed that only ERbeta was transcriptionally active. In conclusion, growing CHO-K1 in serum-free medium does not impact the estrogen responsiveness and this cell line expresses functional ERbeta.

Effect of long-term treatment with steroid hormones or tamoxifen on the progesterone receptor and androgen receptor in the endometrium of ovariectomized cynomolgus macaques

The progesterone receptor (PR) and androgen receptor (AR) belong to the nuclear receptor superfamily. Two isoforms of PR (A and B) have been identified with different functions. The expression of AR, each isoform of PR and their involvement in long-term effects on the endometrium after hormonal replacement therapy (HRT) or tamoxifen (TAM) treatment is not known. The aims of this study were to determine PR(A+B), PRB and AR distribution by immunohistochemistry in the macaque (Macaca fascicularis) endometrium. Ovariectomized (OVX) animals were orally treated continuously for 35 months with either conjugated equine estrogens (CEE); medroxyprogesterone acetate (MPA); the combination of CEE/MPA; or TAM. Treatment with CEE/MPA tended to down-regulate PR in the superficial glands, but increased it in the stroma. TAM treatment increased both the PR and PRB levels in the stroma. Overall, less than 20% of the cells were positive for the PRB isoform and less variation was observed after steroid treatment. AR was found in the stroma, mainly distributed in the basal layer of the endometrium in the OVX and steroid treated groups, but was absent in the TAM treated group. No AR was found in the glandular epithelium. The present data show that long-term hormone treatment affects the PR level, and also the ratio between PRA and PRB in the endometrium.

Expression of progesterone receptors A and B and insulin-like growth factor-I in human myometrium and fibroids after treatment with a gonadotropin-releasing hormone analogue

OBJECTIVE

To determine mRNA and protein expression of the progesterone receptor (PR) and insulin-like growth factor-I (IGF-I) in myometrium and fibroids.

DESIGN

Retrospective clinical study.

SETTING

Hospital-based and university-affiliated research laboratories.

PATIENT(S)

Twelve women in the proliferative phase and six women treated with GnRH analogue (GnRH-a).

INTERVENTION(S)

Blood sampling and collection of myometrium and fibroids.

MAIN OUTCOME MEASURE(S)

PR and IGF-I mRNA levels in fibroids and myometrium were analyzed by solution hybridization and in situ hybridization whereas the proteins were localized by immunohistochemistry.

RESULT(S)

Fibroids and myometrium from women in the proliferative phase showed significantly higher PR mRNA than the corresponding tissues from GnRH-a-treated women. The amount of cells positively stained for PR-AB and PR-B in fibroids and myometrium decreased after GnRH-a treatment compared with in the proliferative phase. The IGF-I mRNA in both fibroids and myometrium in the proliferative phase was significantly higher than those after GnRH-a treatment. The immunostaining of IGF-I showed no difference between the two tissues. There was weaker immunostaining in the GnRH-a-treated group compared with in the proliferative phase group.

CONCLUSION(S)

The shrinkage of fibroids after steroid deprivation is associated with alterations in PR and IGF-I expression.

Transdominant suppression of estrogen receptor signaling by progesterone receptor ligands in uterine leiomyoma cells

Uterine leiomyomas develop in reproductive-age women with high frequency and are dependent on the production of ovarian hormones. While it is generally accepted that these tumors are estrogen (E(2))-responsive, the role of progesterone (P(4)) in modulating tumor growth is less clear. In the present study, an in vivo/in vitro rat model was used to characterize progesterone receptor (PR) isoform expression in uterine leiomyoma and investigate PR signaling using progestins and antiprogestins in the leiomyoma-derived cell line ELT-3. PR-A was the predominant isoform expressed in normal myometrium, leiomyomas and ELT3 cells. In the normal myometrium, PR-A and PR-B levels varied during the estrous cycle with low ratios of PR-A relative to PR-B (PR-A/PR-B) coinciding with times of cell proliferation. Although PR ligands had no effect on basal levels of uterine leiomyoma cell proliferation in vitro, both progestins and antiprogestins inhibited E(2)-stimulated cell proliferation. In addition, E(2)-stimulated transactivation of an estrogen-response-element reporter gene as well as E(2)-induced upregulation of the PR were also inhibited by PR ligands. These data indicate that PR ligands can transdominantly suppress estrogen receptor signaling and stimulation of uterine leiomyoma cell growth.

Signal cross-talk between estrogen receptor alpha and beta and the peroxisome proliferator-activated receptor gamma1 in MDA-MB-231 and MCF-7 breast cancer cells

We have previously demonstrated that peroxisome proliferator-activated receptor gamma (PPARgamma) is expressed and transcriptionally responsive to both synthetic and natural ligands in a variety of human breast cancer cells. We also observed significant differences in basal and ligand-mediated transactivation of PPARgamma in cells with variable expression of the estrogen receptor. While previous reports indicate that PPARgamma can mediate the expression of estrogen target genes, no data have suggested that estrogen receptor (ER) expression can alter the transcriptional regulation of PPARgamma target gene expression. Here we have demonstrated that the expression of either ERalpha or beta, but not the androgen or aryl hydrocarbon receptors, lowers both basal and stimulated PPARgamma-mediated reporter activity. Interestingly, the presence of an ER antagonist does not inhibit this response while estradiol treatment further inhibits the ligand-stimulated transactivation of PPARgamma in cells expressing ERalpha but not ERbeta. Cells transfected with ERalpha deletion mutants demonstrate that the DNA binding domain of the ER is required to repress PPAR transactivation in these cells. Finally, using RNase protection assays we show that the inhibition of PPAR function is not due to a decrease in the expression of PPARgamma. These data suggest that signal cross talk exists bidirectionally between PPARgamma and ER in breast cancer cells.

Estrogens receptors and oxidative damage in the liver

There is considerable evidence that reactive oxygen species (ROS) have a causative role in chronic hepatic injury and cancer development via direct and indirect mechanisms. Estrogens produce free oxygen radicals through redox cycling and affect cell proliferation, also in the liver. We are presently involved in evaluating the possible relationship between estrogens receptor expression, type of receptor, oxidative DNA damage and c-myc in chronic liver disease. The data on DNA adducts, c-myc mRNA and variant estrogen receptor in patients with HCV- or HBV-related chronic liver disease are suggesting that those positive for variant liver estrogen receptor present higher genomic oxidative damage, as reflected in 8-OHdG levels. We are also observing that patients with chronic hepatitis and cirrhosis, when positive for variant estrogen receptor, present higher c-myc m-RNA expression, a factor reportedly associated with increased genomic instability, augmented cytoproliferation and carcinogenesis. Our own and other author's data are shedding new light on estrogen pathophysiology, liver damage and hepatic cancer.

Priming effects of novel nonsteroidal progesterone receptor modulators CP8816 and CP8863 on the development of adenomyosis in the mouse uterus

The possibility of therapeutic application of novel nonsteroidal progesterone receptor modulators CP8816 and CP8863 for preventing the development of uterine adenomyosis was investigated in mice. First priming effects of CP8816 on 17beta-estradiol (E2)-induced cell division in uterine tissues were examined. As a result, pretreatment with CP8816 or progesterone significantly suppressed the elevation of the mitotic activity in the luminal epithelial cells of mice treated with E2 later. Priming with CP8816 had little effect on the stromal cells, but progesterone priming caused an increase of stromal mitotic activity in mice treated with E2 later. To evaluate the inhibitory effect of these compounds on the development of adenomyosis induced experimentally by pituitary grafting, 7-week-old female mice were isografted with a single anterior pituitary in the uterus and divided into four groups. Two groups of mice were given daily subcutaneous injections of 1 mg of CP8816 or the vehicle alone for 6 weeks from the day after the grafting. Remaining two groups of mice were given oral administration of 1 mg of CP8863 or the vehicle only for 5 weeks starting one week after the grafting. The incidence of adenomyosis was significantly lower in the groups of mice treated with CP8816 and CP8863 than in the respective control groups. The mechanism by which CP compounds inhibited the development of adenomyosis might be related to their priming effects, i.e., their inhibitory effect on epithelial cell division and lack of effect on stromal cell division after subsequent exposure to E2.

Developmental expression of progesterone receptor isoforms in the mouse midbrain

Progesterone participates in the regulation of developmental processes in the brain and controls the function of distinct neural circuits. We have studied the expression of progesterone receptor (PR) isoforms in the developing and adult male and female mouse ventral midbrain. Transcripts of both receptor isoforms (PR-A and B) were detectable pre- and postnatally but regulated differentially during ontogeny. Immunoblotting revealed that only the full-length form (PR-B) is transcribed transiently into protein, whereas the truncated PR-A isoform is not detectable as protein. Although the precise function of progesterone in the developing CNS is not fully understood, our data implicate a potential role for PR signaling for the developing nigrostriatal system.

Effects of the maturation-inducing steroid on LH secretion and the GnRH system at different stages of the gonadal cycle in Atlantic croaker

The effects of treatment with the maturation-inducing steroid 17,20beta,21-trihydroxy-4-pregnen-3-one (20beta-S) on luteinizing hormone-releasing hormone analog (LHRHa)-induced LH secretion were examined during several phases of the gonadal cycle in Atlantic croaker, Micropogonias undulatus. 20beta-S (1 and 5 microg/g of body wt) was administered by intraperitoneal (ip) injection, 24 h prior to injection with LHRHa (10-50 ng/g of body wt) and fish were bled 1 h after LHRHa injection. Treatment with both doses of 20beta-S resulted in plasma concentrations of the steroid within the normal physiological range for this species during final oocyte maturation and ovulation. The 20beta-S treatments altered the LH response to LHRHa throughout the reproductive cycle in both sexes, but the direction and magnitude of the response varied. 20beta-S treatment decreased the LH response to LHRHa in fish with recrudescing and fully recrudesced gonads and in females with regressed gonads. On the other hand, 20beta-S treatment significantly increased the LH response to LHRHa in males with regressing or regressed gonads. 20beta-S treatment also altered preoptic anterior hypothalamic (POAH) and pituitary seabream gonadotropin-releasing hormone (sbGnRH) contents, and the patterns of these changes were similar to those observed in LH secretion. The finding that moderate increases in plasma 20beta-S concentrations, similar to those occurring during final oocyte maturation, significantly inhibit the LH response to LHRHa at the end of the reproductive cycle suggests that this action of 20beta-S is of physiological importance during the periovulatory period. Moreover, the fact that concurrent changes occur in POAH and pituitary sbGnRH contents suggests that the actions of 20beta-S on LH secretion are at least partly mediated via the GnRH system.