Irilone, a Red Clover Isoflavone, Combined with Progesterone Enhances PR Signaling through the Estrogen and Glucocorticoid Receptors

Trifolium pratense L. (red clover) is a popular botanical supplement used for women's health. Irilone isolated from red clover previously demonstrated progestogenic potentiation activity. In this study, irilone enhanced progesterone signaling was determined to not occur due to post-translational phosphorylation or by reducing progesterone receptor (PR) protein levels but instead increased PR protein levels in T47D breast cancer cells, which could be blocked by estrogen receptor (ER) antagonists, suggesting an ER dependent effect. Further, irilone increased luciferase activity from a hormone responsive element in a cell line that lacked ER and PR but expressed the glucocorticoid receptor (GR). A siRNA knockdown of GR in Ishikawa PR-B endometrial cancer cells reduced irilone's ability to enhance progesterone signaling. In an ovariectomized CD-1 mouse model, irilone did not induce uterine epithelial cell proliferation. The mechanism of action of irilone gives insight into PR crosstalk with other steroid hormone receptors, which can be important for understanding botanicals that are used for women's health.

Low-dose aspirin can downregulate progesterone resistance and increase the expression of LIF in endometriosis during the implantation window

AIM

Study the effect of low-dose aspirin on the endometrial receptivity in endometriosis rat models.

MATERIALS AND METHODS

This study is to explore the expressions of progesterone receptor and LIF among three groups of endometriosis rat models: control group (n = 12), EMs group (n = 15), and aspirin group (n = 17). The expressions of progesterone receptor (PR), PRA, PRB, and leukemia inhibitory factor receptor (LIFR) in eutopic endometrium were determined using immunohistochemistry technology, western blot, and qRT-PCR. The levels of LIF in eutopic endometrium and serum were detected by western blot, qRT-PCR, and ELISA.

RESULTS

The expressions of PR, PRA, and PRB protein were significantly increased in the eutopic endometrium after low-dose aspirin treatment, and the level of PRB mRNA was also increased while the ratio of PRA/PRB mRNA was decreased in the eutopic endometrium. The levels of LIF in eutopic endometrium and serum were increased compared with the untreated endometriosis rats. However, the expression of LIFR was not statistically different among the three groups.

CONCLUSIONS

The results suggest that the low-dose aspirin treatment could downregulate progesterone resistance and increase the expression of LIF of endometriosis rats during the implantation window, which could improve endometrial receptivity and enhance the pregnant rate of endometriosis. It may provide a potential treatment method for endometriosis-related infertility.

The endometrial response to modulation of ligand-progesterone receptor pathways is reversible

OBJECTIVE

To study the impact of the progesterone receptor modulator (PRM), ulipristal acetate (UPA), on endometrial morphology and function.

DESIGN

Cross-sectional.

SETTING

University Research Institute.

PATIENT(S)

Endometrial biopsies from 16 patients with heavy menstrual bleeding with a structurally normal uterus or in association with structural abnormalities identified on radiological imaging (fibroids, adenomyosis or a combination of fibroids and adenomyosis).

INTERVENTION(S)

Participants received UPA (5 mg once daily) for three 12-week courses, each separated by 4 weeks without treatment.

MAIN OUTCOME MEASURE(S)

Gene expression by real-time quantitative reverse transcription polymerase chain reaction, immunohistochemistry, and digital image analysis were analyzed to investigate the endometrial impact of modulation of progesterone receptor pathways upon expression of steroid receptors, steroid metabolizing enzymes, cell proliferation, and progesterone-regulated genes in the same patients at 3 time points: before, during, and after discontinuation of PRM treatment.

RESULT(S)

Ulipristal acetate treatment resulted in increased messenger ribonucleic acid (mRNA) levels of steroid receptors compared with pretreatment secretory endometrium; decreased mRNA levels of 17- and 11-beta-hydroxysteroid dehydrogenases compared with pretreatment proliferative endometrium and pretreatment secretory endometrium; reduced cell proliferation compared with pretreatment proliferative endometrium; and altered mRNA levels of progesterone-regulated genes. A strong consistency between immunohistochemistry-digital image analysis and real-time quantitative reverse transcription polymerase chain reaction results was evident. Alterations in the mRNA levels and endometrial morphology returned to a pretreatment phenotype after the cessation of PRM exposure.

CONCLUSION(S)

The endometrial impact of the modulation of progesterone receptor pathways with PRM (UPA) treatment is reversible.

CLINICAL TRIAL REGISTRATION NUMBER

Ulipristal acetate versus conventional management of heavy menstrual bleeding (UCON) trial (EudraCT 2014-003408-65; REC14/LO/1602).

Structural binding perspectives of a major tobacco alkaloid, nicotine, and its metabolite cotinine with sex-steroid nuclear receptors

Globally, more than a billion people smoke tobacco making it one of the biggest public health problems and a leading risk factor for global deaths. Nicotine, the main alkaloid in tobacco, has been shown to be associated with fertility problems in men and women. The adverse effects of tobacco/nicotine on reproduction have been attributed to deleterious effects on gametes, steroidogenic imbalance, and competitive inhibition of steroid receptors. The present study reports the sex-steroid receptor disrupting potential of nicotine and its major metabolite cotinine against the estrogen receptor-α (ERα), ERβ, androgen receptor (AR), and progesterone receptor (PR). Both ligands bound in the ligand-binding pockets of ERα, ERβ, AR and PR and formed important hydrophobic interactions with different amino-acid residues of receptors. Most of the residues of ERα, ERβ, AR and PR interacting with nicotine and cotinine were common with those of native/bound ligands of the receptors. Interacting amino acids most important for binding of nicotine and cotinine with each receptor were identified by loss in accessible surface area. Amino acids Leucine-346, Leucine-384 and Phenylalanine-404 for ERα; Methionine-336, Phenylalanine-356 and Leucine-298 for ERβ; and Leucine-704 and Leucine-718, respectively for AR and PR, were the most important residues for binding with nicotine and cotinine. Among the four receptors, based on the number of interactions, nicotine and cotinine had greater potential to interfere in the signaling of ERβ. In conclusion, the results suggested that nicotine and cotinine bind and interact with sex-steroid nuclear receptors and have potential to interfere in the steroid hormone signaling resulting in reproductive dysfunction.

Dopamine-induced interactions of female mouse hypothalamic proteins with progestin receptor-A in the absence of hormone

Neural progestin receptors (PR) function in reproduction, neural development, neuroprotection, learning, memory and the anxiety response. In the absence of progestins, PR can be activated by dopamine (DA) in the rodent hypothalamus to elicit female sexual behaviour. The present study investigated mechanisms of DA activation of PR by testing the hypothesis that proteins from DA-treated hypothalami interact with PR in the absence of progestins. Ovariectomised, oestradiol-primed mice were infused with a D1-receptor agonist, SKF38393 (SKF), into the third ventricle 30 minutes prior to death. Proteins from SKF-treated hypothalami were pulled-down with glutathione S-transferase-tagged mouse PR-A or PR-B and the interactomes were analysed by mass spectrometry. The largest functional group to interact with PR-A in a DA-dependent manner was synaptic proteins. To test the hypothesis that DA activation of PR regulates synaptic proteins, we developed oestradiol-induced PR-expressing hypothalamic-like neurones derived from human-induced pluripotent stem cells (hiPSCs). Similar to progesterone (P4), SKF treatment of hiPSCs increased synapsin1/2 expression. This SKF-dependent effect was blocked by the PR antagonist RU486, suggesting that PR are necessary for this DA-induced increase. The second largest DA-dependent PR-A protein interactome comprised metabolic regulators involved in glucose metabolism, lipid synthesis and mitochondrial energy production. Interestingly, hypothalamic proteins interacted with PR-A, but not PR-B, in an SKF-dependent manner, suggesting that DA promotes the interaction of multiple hypothalamic proteins with PR-A. These in vivo and in vitro results indicate novel mechanisms by which DA can differentially activate PR isoforms in the absence of P4 and provide a better understanding of ligand-independent PR activation in reproductive, metabolic and mental health disorders in women.

Pharmacokinetics and Safety of the Novel Selective Progesterone Receptor Modulator Vilaprisan in Participants With Renal Impairment

This open label, parallel-group study investigated the pharmacokinetics and safety of a single oral 2-mg dose of the novel selective progesterone receptor modulator vilaprisan in participants with impaired renal function compared with age, weight, sex, and race matched controls with normal renal function. Systemic exposure (area under the plasma concentration-time curve [AUC]) and maximum observed concentrations (Cmax ) were compared among 9 participants with moderate renal impairment and matched controls by ANOVA. An additional 4 participants, each with severe renal impairment or normal renal function, contributed to a linear regression analysis exploring any monotone relationship between individual variables and the estimated glomerular filtration rate. The geometric mean AUC was increased by a factor of 1.35 in renally impaired participants compared to normal controls (not statistically significant: least squares mean, 1.346; 90% confidence interval, 0.918-1.973). Cmax was similar in participants with moderate renal impairment and normal renal function (least squares mean, 1.026; 90% confidence interval, 0.779-1.351). Considering the overall variability, there was no correlation between renal function (estimated glomerular filtration rate) and Cmax or AUC of vilaprisan. Single oral administration of vilaprisan 2 mg was well tolerated by all participants, both men and women and irrespective of renal function. The incidence of treatment-emergent adverse events was similar across all groups. Results from this study do not indicate that a dose adjustment will be necessary for vilaprisan when treating patients up to moderate renal impairment.

Breast cancer amelioration by Butea monosperma in-vitro and in-vivo

ETHNOPHARMACOLOGICAL RELEVANCE

Butea monosperma belonging to family Fabaceae is used in the Indian traditional medicine (Ayurveda) for various ailments including abdominal tumors and possess anti-estrogenic activity.

AIM OF THE STUDY

The present study is aimed at investigating the chemo-preventive potential of Butea monosperma in breast cancer and elucidating it's mechanism of action by assessing its effect on key processes like apoptosis, angiogenesis and metastasis.

METHODS

Cytotoxic potential of methanol extract of Butea monosperma flower (MEBM) was tested in MCF-7 (estrogen receptor positive), MDA-MB-231 (triple negative) and MDA-MB-453 (HER2 positive) human breast cancer cells by MTT assay. Chemo-preventive potential was evaluated in-vivo in Methylnitrosourea (MNU) induced mammary cancer in nulliparous Sprague-Dawley rats. The mechanism for anticancer potential was screened by in-vitro studies involving Annexin V- FITC assay (apoptosis), Chick Chorioallantoic Membrane assay (angiogenesis) and Migration assay (metastasis). Statistical analysis was done by one way and two way ANOVA (for Growth Rate and feed consumption efficiency) followed by post hoc Bonferroni's test with P value < 0.05.

RESULTS

It is observed that the exposure of MEBM, at various concentrations and time intervals to different cell lines, resulted in decreased cell proliferation. The IC₅₀ value of MCF-7 cells was found significantly less than that of MDA-MB-231 and MDA-MB-453 cells, which indicated that the extract of said medicinal plant were more potent inhibitors of estrogen positive breast cancer cells than other types of breast cancer cells in vitro. Corroborative evidences were acquired in MNU actuated mammary carcinogenesis where MEBM constricted tumor parameters, decreased expression of estrogen and progesterone, nucleic acid content and increased latency period. MEBM also induced apoptosis, inhibited angiogenesis and metastasis in-vitro.

CONCLUSION

Selective cytotoxic activity in MCF-7 estrogen positive breast cancer cells and inhibition of growth of mammary carcinoma in-vivo by methanol extract of Butea monosperma flowers (MEBM) suggests chemo-prevention through modulation of estrogen and progesterone receptor, apoptotic, anti-angiogenesis and anti-metastatic activity.

Hormone Treatment and Sex Steroid Receptors in Metastatic Renal Cell Carcinoma: Report of a Multicentric Prospective Study

Twenty-eight patients with metastatic renal cell carcinoma entered a multicentric prospective study to evaluate the response to high-dose medroxyprogesterone acetate (MPA) and testosterone in MPA failures in relation to sex steroid receptors. No objective remission was seen in the 24 evaluable patients, and only disease stabilizations of short duration were achieved in one-third of treated patients. Stabilizations achieved with second line testosterone were all seen in patients unresponsive to MPA. Receptor studies demonstrated that estrogen, progesterone, or androgen receptors were found in low concentrations and in only 6 of 23 tumors (26%) and 13 normal tissue samples (56%). Surprisingly, no disease stabilization was achieved in patients positive for receptors. It can be concluded that the occasional objective responses to hormone therapy reported in the literature may have been due to some cytotoxic effect of hormone therapy rather than to a true hormonal mechanism.

Changes in Receptor Status after Treatment with Tamoxifen in Endometrial Cancer

Estrogen (ER) and progesterone receptor (PgR) status was determined in 41 women with operable endometrial cancer before and after administration of tamoxifen (TAM). The first sample was obtained by hysteroscopy to ensure a precise biopsy of neoplastic tissue; the second was done on the surgical specimen. PgR content was significantly increased after TAM treatment and this data was compared with the degree of tumor differentiation.

Efficacy, safety and recurrence of new progestins and selective progesterone receptor modulator for the treatment of endometriosis: a comparison study in mice

BACKGROUND

Current medical treatments for endometriosis are very limited. Progestin and selective progesterone receptor modulators (SPRM) are developed but their efficacy, safety, mechanism and recurrence in endometriosis are not fully studied.

METHODS

In order to compare therapeutic, side effects and therapeutic actions of Esmya, Duphaston and Dienogest in endometriosis. Experimental endometriosis was induced by either intraperitoneal or subcutaneous mouse endometrium transplantation. Lesion size, weight and histology at the end of intervention were compared. Expression of related markers in the endometriotic lesions were examined. Body, uterus and ovary weights, endometrial glands and thickness (ETI), and follicle count were measured. For recurrent study, lesion growth before and after intervention was monitored.

RESULTS

After Esmya, Duphaston, Dienogest treatment, lesion size and weight were significantly decreased. Proliferation Pcna expression was significantly decreased in all groups, but proliferation cells were significantly decreased only in Duphaston group. Apoptosis Mapk1 expression and TUNEL-positive cells were significantly increased in Duphaston group. Adhesion Mmp2 and Itgavβ3 expression were significantly increased in Esmya group. Plau, Hif1α and Vegfa expression, peritoneal fluid PGE2 levels, and ERα and ERβ expression were not affected; while PR expression was significantly lower in all groups. Endometrial gland count in uterus was significantly increased in Dienogest group, ETI was significantly decreased in Duphaston group, and AFC were significantly increased in Esmya group. Upon treatment cessation, lesion growth rebound quickly in Dienogest and Duphaston groups, but slowly in Esmya group.

CONCLUSION

Esmya, Duphaston and Dienogest are effective anti-endometriosis drugs targeting proliferation, apoptosis and adhesion. Esmya, Duphaston and Dienogest are all well tolerable, although endometrial glandular hyperplasia was found in Dienogest, endometrial atrophy in Duphaston, follicle accumulation in Esmya.

Progesterone agonists and antagonists induce down– and up–regulation of estrogen receptors and estrogen inducible genes in human breast cancer cell lines

The effects of the synthetic progestin R5020 and the antiprogestin RU486 on the cellular content of estrogen receptors (ER) and on cell responsiveness to estrogens, have been investigated in the sex hormone-sensitive human breast cancer cell lines MCF-7 and T47D. When T47D cells were treated with R5020 (Promegestone) (10–8 M), ER was down-regulated to about 50% of the control level in a time-dependent manner. Maximum down-regulation was observed after 24 hours and remained at this level for the next 24 hours. Dihydrotestosterone (DHT) or dexamethasone (DEX) had no effect on ER sites. R5020 also down-regulated, although to a lesser extent, ER in the MCF-7 cells which contain fewer progesterone receptor (PR) sites.

When MCF-7 cells were transfected with a progesterone receptor expression vector (tMCF-7) to increase the number of PR sites, R5020 down-regulated the ER to a level similar to that reached in T47D cells. In both cell lines ER down-regulation was completely inhibited by a 10-fold molar excess of the antiprogestin RU486 (Mifepristone) (10–7 M). Surprisingly, when incubated with RU486 alone, T47D cells responded by up-regulating ER 2-4 fold.

The functional relevance of inhibition and up-regulation of ER for the estrogen responsiveness of hormone-sensitive human breast cancer cells was tested by assaying the synthesis of an estrogen-regulated product, the PS2 protein. Estrogen induction of this protein was inhibited by at least 70% in T47D cells exposed to R5020 for 24 hours before estrogen administration and by about 25% in MCF-7 cells under the same conditions. A 55% inhibition was observed in tMCF-7 cells. Up-regulation of ER by RU486 in T47D cells led to an increase in the estrogen induction of PS2 by about 18-20% compared to RU486 untreated cells.

These results indicate that the progestin and antiprogestin regulation of ER is functionally important for the estrogen responsiveness of breast cancer cells.

Sex Differences in Steroid Receptor Coexpression and Circadian-Timed Activation of Kisspeptin and RFRP-3 Neurons May Contribute to the Sexually Dimorphic Basis of the LH Surge

In rodents, the ovulation-inducing luteinizing hormone (LH) surge is sexually dimorphic, occurring only in females, but the reasons for this sex difference are unclear. Two neuropeptides, kisspeptin and RFamide-related peptide 3 (RFRP-3), are hypothesized to regulate the gonadotropin-releasing hormone (GnRH)/LH surge. In females, both of these systems show circadian changes coincident with the LH surge, but whether males show similar temporal changes under comparable hormonal conditions is unknown. Here, we evaluated circadian time (CT)-dependent changes in gene expression and neuronal activation of Kiss1 and Rfrp neurons of female and male mice given identical LH surge-inducing estrogen regimens. As expected, females, but not males, displayed a late afternoon LH surge and GnRH neuronal activation. Kiss1 expression in the anteroventral periventricular nucleus (AVPV) was temporally increased in females in the late afternoon, whereas males demonstrated no temporal changes in AVPV Kiss1 expression. Likewise, neuronal activation of AVPV Kiss1 neurons was dramatically elevated in the late afternoon in females but was low at all circadian times in males. Estrogen receptor α levels in AVPV Kiss1 neurons were sexually dimorphic, being higher in females than males. AVPV progesterone receptor levels were also higher in females than males. Hypothalamic Rfrp messenger RNA levels showed no CT-dependent changes in either sex. However, Rfrp neuronal activation was temporally diminished in the afternoon/evening in females but not males. Collectively, the identified sex differences in absolute and CT-dependent AVPV Kiss1 levels, AVPV sex steroid receptor levels, and circadian-timed changes in neuronal activation of both Kiss1 and Rfrp neurons suggest that multiple sexually dimorphic processes in the brain may underlie proper LH surge generation.

Coordinated Regulation Among Progesterone, Prostaglandins, and EGF-Like Factors in Human Ovulatory Follicles

CONTEXT

In animal models, the luteinizing hormone surge increases progesterone (P4) and progesterone receptor (PGR), prostaglandins (PTGs), and epidermal growth factor (EGF)-like factors that play essential roles in ovulation. However, little is known about the expression, regulation, and function of these key ovulatory mediators in humans.

OBJECTIVE

To determine when and how these key ovulatory mediators are induced after the luteinizing hormone surge in human ovaries.

DESIGN AND PARTICIPANTS

Timed periovulatory follicles were obtained from cycling women. Granulosa/lutein cells were collected from in vitro fertilization patients.

MAIN OUTCOME MEASURES

The in vivo and in vitro expression of PGR, PTG synthases and transporters, and EGF-like factors were examined at the level of messenger RNA and protein. PGR binding to specific genes was assessed. P4 and PTGs in conditioned media were measured.

RESULTS

PGR, PTGS2, and AREG expressions dramatically increased in ovulatory follicles at 12 to 18 hours after human chorionic gonadotropin (hCG). In human granulosa/lutein cell cultures, hCG increased P4 and PTG production and the expression of PGR, specific PTG synthases and transporters, and EGF-like factors, mimicking in vivo expression patterns. Inhibitors for P4/PGR and EGF-signaling pathways reduced hCG-induced increases in PTG production and the expression of EGF-like factors. PGR bound to the PTGS2, PTGES, and SLCO2A1 genes.

CONCLUSIONS

This report demonstrated the time-dependent induction of PGR, AREG, and PTGS2 in human periovulatory follicles. In vitro studies indicated that collaborative actions of P4/PGR and EGF signaling are required for hCG-induced increases in PTG production and potentiation of EGF signaling in human periovulatory granulosa cells.

Estrogen-dependent estrous behavior in rabbits is antagonized by the antiprogestin RU486

Estrogen receptor-alpha (ERα) dimerizes with unliganded progesterone receptor (PR) in target tissues to trigger genomic and non-genomic effects. In ovariectomized rats the antiprogestin RU486 or antisense nucleotides against PR antagonize estradiol-induced sexual receptivity. We determined the relevance of unliganded PR for the expression of estrogen-dependent scent-marking (chinning) and sexual receptivity by injecting RU486 to: a) ovariectomized (ovx) rabbits given estradiol benzoate (EB; 5μg/day); b) intact rabbits. Chinning and lordosis were quantified in ovx animals before (5days; baseline) and during hormonal treatments: EB+RU486 (20mg/day; n=18) or EB+vehicle (n=18). On treatment day 4 LQ (lordosis quotient) increased in both groups, relative to baseline (mean±se): LQ=1±5 (baseline) vs 25±21 (EB+RU486) and 2±6 (baseline) vs 37±29 (EB+vehicle). On day 9 LQ values were: 22±23 (EB+RU486) and 54±39 (EB+vehicle). Chinning increased only in the EB+vehicle group (day 9=55±46 vs baseline=17±20 marks/10min). In intact rabbits one RU486 injection: reduced the LQ from 72±7to 36±8 five hrs later, increased the latency to receive first ejaculation from 45 to 98s, and decreased the number of ejaculations received in the test from 3 to 2 but did not modify mounting latency or chinning. Results support a participation of unliganded PR for the induction (ovx) and maintenance (intact) of rabbit estrous behavior by estrogens.

Selective progesterone receptor modulators: new possibilities for gynecologic hormone therapy

Progesterone regulates several female reproductive functions. Progesterone and synthetic progestins derived from it have long been utilized in gynecology. The effects of these steroids in target cells are mediated via progesterone receptors, Progesterone receptors are also the target of action of selective progesterone receptor modulators. Of the molecules of this newer group of drugs, two are presently in clinical use. Mifepristone is used in nonsurgical abortion, in softening of the cervix before surgical abortion, and in the induction of labor in cases of intrauterine death. The indications of ulipristal acetate are postcoital contraception and treatment of uterine myomas and the resulting symptoms.

Deciphering the divergent roles of progestogens in breast cancer

Most breast cancers are driven by oestrogen receptor-α. Anti-oestrogenic drugs are the standard treatment for these breast cancers; however, treatment resistance is common, necessitating new therapeutic strategies. Recent preclinical and historical clinical studies support the use of progestogens to activate the progesterone receptor (PR) in breast cancers. However, widespread controversy exists regarding the role of progestogens in this disease, hindering the clinical implementation of PR-targeted therapies. Herein, we present and discuss data at the root of this controversy and clarify the confusion and misinterpretations that have consequently arisen. We then present our view on how progestogens may be safely and effectively used in treating breast cancer.

Changes of expression of estrogen and progestrone receptors, human epithelial growth factor receptor 2 and Ki-67 after neoadjuvant chemotherapy in the treatment of breast cancer

Recent studies suggest that the development and prognosis of breast cancer is in close correlation to molecular subtype of breast cancer. Neoadjuvant chemotherapy has been extensively applied in the treatment of local breast cancer in advanced stage. In order to verify the correlation between expression changes of estrogen receptor, progestrone receptor, human epithelial growth factor receptor 2 and Ki-67 after neoadjuvant chemotherapy and neoadjuvant chemotherapy, we studied 120 patients with stage IIAIIIC breast cancer who underwent neoadjuvant chemotherapy in Binzhou Medical University Hospital, Shandong, China from February 2011 to February 2015. Clinical characteristics were retrospectively analyzed. The expression of estrogen receptor, progesterone receptor, human epithelial growth factor receptor 2 and Ki-67 of patients were detected using the immunohistochemical method before and after neoadjuvant chemotherapy. The results suggest that the overall remission rate of neoadjuvant chemotherapy was 76.7% (92/120) of which 16.7% (20/120) of cases had complete remission, 60% (72/120) had partial remission and 23.3% (28/120) were stable. There were no cases of progressive disease. The property of estrogen receptor and the expression of Ki-67 of primary tumor were correlated to the remission rate of neoadjuvant chemotherapy (P less than 0.05). The expression of Ki-67 had a significant decline after neoadjuvant chemotherapy, and the difference had statistical significance (P less than 0.05). The difference in expression of estrogen receptor, progesterone receptor and human epithelial growth factor receptor 2 before and after neoadjuvant chemotherapy had statistical significance (P > 0.05). Hence, it can be concluded that breast cancer patients with negative estrogen receptor expression and high Ki-67 expression before neoadjuvant chemotherapy can achieve better curative effects. Neoadjuvant chemotherapy cannot change the expression states of estrogen receptor, progesterone receptor and human epithelial growth factor receptor 2, but it can lower the expression level of Ki-67. Ki-67 can also be used for predicting the curative effect of neoadjuvant chemotherapy.

Multiplexing Fluorescence Polarization Assays to Increase Information Content Per Screen: Applications for Screening Steroid Hormone Receptors

As the push to reduce cost per well in high-throughput screening reaches the practical limitations of liquid handling, future cost savings will likely arise from an increase in information content per well. One strategy to increase information content is to perform discreet assays against multiple targets in a single well. In such assays, reagent usage and liquid handling steps do not scale-up in direct proportion to the increase in information content, providing for a simple method to increase data points per screen without further reductions in assay volume. The authors have used tracers incorporating the spectrally distinct fluorophores fluorescein and TAMRA to develop a high-throughput assay to identify selective estrogen receptor α or proges-terone receptor ligands. Selectivity is assessed immediately in this assay, with no requirement for separate follow-up screening to determine selectivity. This methodology is easily adaptable to other target classes.

The place of selective progesterone receptor modulators in myoma therapy

Uterine fibroids are the most commonly encountered benign uterine tumors in women of reproductive age. As progesterone is known to play a key role in promoting myoma growth, the goal of the study was to analyze the efficacy of selective progesterone receptor modulators (SPRMs). From four studies, it was concluded that UPA (ulipristal acetate) treatment was able to control myoma-associated uterine bleeding in over 90% of cases and significantly reduce myoma volume in more than 80% of women. The results of long-term intermittent therapy (PEARL III and PEARL IV studies) (4 courses of 3 months) demonstrated that more than one course of UPA is able to maximize its potential benefits in terms of control of bleeding and fibroid volume reduction. The treatment was considered safe, even at the level of endometrial changes. With the advent of SPRMs, new algorithms should be discussed, as there is no doubt that there is a place for medical therapy with SPRMs in the current armamentarium of fibroid management.

An in vitro investigation on the cytotoxic and nuclear receptor transcriptional activity of the mycotoxins fumonisin B1 and beauvericin

Fumonisin B1 (FB1) and beauvericin (BEA) are secondary metabolites of filamentous fungi, which under appropriate temperature and humidity conditions may develop on various foods and feeds. To date few studies have been performed to evaluate the toxicological and endocrine disrupting effects of FB1 and BEA. The present study makes use of various in vitro bioassays including; oestrogen, androgen, progestagen and glucocorticoid reporter gene assays (RGAs) for the study of nuclear receptor transcriptional activity, the thiazolyl blue tetrazolium bromide (MTT) assay to monitor cytotoxicity and high content analysis (HCA) for the detection of pre-lethal toxicity in the RGA and Caco-2 human colon adenocarcinoma cells. At the receptor level, 0.001-10μM BEA or FB1 did not induce any agonist responses in the RGAs. However at non-cytotoxic concentrations, an antagonistic effect was exhibited by FB1 on the androgen nuclear receptor transcriptional activity at 10μM and BEA on the progestagen and glucocorticoid receptors at 1μM. MTT analysis showed no decrease in cell viability at any concentration of FB1, whereas BEA showed a significant decrease in viability at 10μM. HCA analysis confirmed that the reduction in the progestagen receptor transcriptional activity at 1μM BEA was not due to pre-lethal toxicity. In addition, BEA (10μM) induced significant toxicity in both the TM-Luc (progestagen responsive) and Caco-2 cells.

In vitro bioassay investigations of the endocrine disrupting potential of steviol glycosides and their metabolite steviol, components of the natural sweetener Stevia

The food industry is moving towards the use of natural sweeteners such as those produced by Stevia rebaudiana due to the number of health and safety concerns surrounding artificial sweeteners. Despite the fact that these sweeteners are natural; they cannot be assumed safe. Steviol glycosides have a steroidal structure and therefore may have the potential to act as an endocrine disruptor in the body. Reporter gene assays (RGAs), H295R steroidogenesis assay and Ca(2+) fluorimetry based assays using human sperm cells have been used to assess the endocrine disrupting potential of two steviol glycosides: stevioside and rebaudioside A, and their metabolite steviol. A decrease in transcriptional activity of the progestagen receptor was seen following treatment with 25,000 ng/ml steviol in the presence of progesterone (157 ng/ml) resulting in a 31% decrease in progestagen response (p=<0.01). At the level of steroidogenesis, the metabolite steviol (500-25,000 ng/ml) increased progesterone production significantly by 2.3 fold when exposed to 10,000 ng/ml (p=<0.05) and 5 fold when exposed to 25,000 ng/ml (p=<0.001). Additionally, steviol was found to induce an agonistic response on CatSper, a progesterone receptor of sperm, causing a rapid influx of Ca(2+). The response was fully inhibited using a specific CatSper inhibitor. These findings highlight the potential for steviol to act as a potential endocrine disruptor.

Relationship Between Gonadotropin-Releasing Hormone/Gonadotropin-Releasing Hormone Receptor Signaling and Progesterone Receptors in Human Trophoblasts

OBJECTIVE

To investigate the relationship between gonadotropin-releasing hormone (GnRH)/gonadotropin-releasing hormone receptor (GnRHR) signaling and progesterone receptors (PGRs).

STUDY DESIGN

HTR-8/SV neo cells and JEG-3 cells were incubated for 24 hours with GnRH-I or -II. The expression of PGRs was measured by quantitative real-time reverse transcriptase-polymerase chain reaction and Western blotting.

RESULTS

In both cells lines after incubation with 1-1,000 nM/L GnRH-I or -II the ratio of PGR-B to PGR-AB mRNA level did not differ in any of the groups as compared to the control. Relatively higher expression of PGR-B than PGR-A mRNA and expression of only PGR-B protein without PGR-A protein were observed in all specimens. There were no significant differences in the expression of PGR-B protein in each group when compared to the control group after incubation with GnRH-I or -II at 0.001-1,000 mM/L in both cell lines.

CONCLUSION

PGRs are expressed regardless of GnRH/GnRHR signaling in human trophoblasts, in which PGR-B expression is more dominant than PGR-A expression.

Endometrial Effects of Prolonged Therapy with the Selective Progesterone Receptor Modulator Ulipristal Acetate: A Case Report

BACKGROUND

Prolonged exposure to a selective progesterone receptor modulator (ulipristal acetate) in a patient with benign metastasizing leiomyoma did not result in endometrial hyperplasia or neoplasia.

CASE

A woman with history of benign metastasizing leiomyoma underwent medical treatment for 5 years with ulipristal acetate. Endometrial biopsies were performed at established intervals to monitor for intraepithelial neoplasia or progesterone receptor modulator-associated endometrial changes (PAECs). The patient tolerated UPA therapy well; there was no evidence of hyperplasia or proliferative changes associated with progesterone-associated endometrial changes.

CONCLUSION

In this case prolonged exposure to ulipristal acetate did not result in premalignant or malignant endometrial pathology.

Endocrine-Disrupting Activity of Hydraulic Fracturing Chemicals and Adverse Health Outcomes After Prenatal Exposure in Male Mice

Oil and natural gas operations have been shown to contaminate surface and ground water with endocrine-disrupting chemicals. In the current study, we fill several gaps in our understanding of the potential environmental impacts related to this process. We measured the endocrine-disrupting activities of 24 chemicals used and/or produced by oil and gas operations for five nuclear receptors using a reporter gene assay in human endometrial cancer cells. We also quantified the concentration of 16 of these chemicals in oil and gas wastewater samples. Finally, we assessed reproductive and developmental outcomes in male C57BL/6J mice after the prenatal exposure to a mixture of these chemicals. We found that 23 commonly used oil and natural gas operation chemicals can activate or inhibit the estrogen, androgen, glucocorticoid, progesterone, and/or thyroid receptors, and mixtures of these chemicals can behave synergistically, additively, or antagonistically in vitro. Prenatal exposure to a mixture of 23 oil and gas operation chemicals at 3, 30, and 300 μg/kg · d caused decreased sperm counts and increased testes, body, heart, and thymus weights and increased serum testosterone in male mice, suggesting multiple organ system impacts. Our results suggest possible adverse developmental and reproductive health outcomes in humans and animals exposed to potential environmentally relevant levels of oil and gas operation chemicals.

Characterization of a Hormone-Responsive Organotypic Human Vaginal Tissue Model: Morphologic and Immunologic Effects

Estrogen and progesterone regulate proliferation and differentiation of epithelial cells in the female genital tract. We investigated the effects of these hormones on reconstructed human organotypic vaginal epithelial tissue models (EpiVaginal). We ascertained that epithelial cells in the tissue models express estrogen and progesterone receptors. Treatment with estradiol-17β (E(2)) significantly increased epithelium thickness and transepithelial electrical resistance (TEER), whereas progesterone (P) treatment resulted in thinning of the epithelium and decreased TEER when compared with untreated controls. Exposure to E(2) increased (1) the expression of the progesterone receptor B (PR-B), (2) accumulation of glycogen in suprabasal cells, (3) epithelial differentiation, and (4) the expression of a number of gene pathways associated with innate immunity, epithelial differentiation, wound healing, and antiviral responses. These findings indicate that EpiVaginal tissues are hormone responsive and can be used to study the role of female reproductive hormones in innate immune responses, microbial infection, and drug delivery in the vaginal mucosa.

Evaluation of biomarker changes after administration of various neoadjuvant chemotherapies in breast cancer

To assess the changes in estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2) and Ki-67 expression in breast cancer patients after various neoadjuvant chemotherapies. Data from 138 locally advanced breast cancer patients with histological diagnoses were reviewed. Seventy patients (group 1) were given 4 cycles of 500 mg/m(2) cyclophosphamide and 50 mg/m(2) pirarubicin every 21 days. Sixty-eight patients (group 2) were given 4 cycles of 500 mg/m(2) cyclophosphamide and 75 mg/m(2) docetaxel every 21 days. The biomarker changes of the operated tumor tissues were compared with the initial core biopsies. ER, PR, HER2 and Ki-67 expression changed by 28.6%, 22.9%, 17.1% and 54.3%, respectively, after neoadjuvant chemotherapy in group 1 and 16.2%, 22.1%, 13.2% and 70.6%, respectively, after neoadjuvant chemotherapy in group 2. There were significant differences between the groups regarding ER and Ki-67 status changes, and these changes can be used to inform treatment strategies.

Optimal systemic therapy for premenopausal women with hormone receptor-positive breast cancer

Although systemic therapy is one of the cornerstones of therapy for premenopausal women with early stage breast cancer, there remain many unknowns regarding its optimal use. By accident of clinical trial design, much clinical investigation in premenopausal women has focused on chemotherapy. More recently the value of endocrine therapy (tamoxifen and ovarian suppression/ablation via surgery, LHRH agonists, or chemotherapy-induced menopause) has become apparent, and some form of endocrine therapy is viewed as standard for virtually all premenopausal women with early stage invasive breast cancer that expresses estrogen and/or progesterone receptor. Critical open questions include type and duration of endocrine therapy and the development of prognostic/predictive markers to help identify patients who are likely to benefit from chemotherapy in addition to endocrine therapy. For some years, five years of tamoxifen has been viewed as the standard endocrine therapy for premenopausal hormone-responsive breast cancer, although the ATLAS trial suggests that an additional five years of tamoxifen can be considered. The MA17 trial also suggests that an additional five years of an aromatase inhibitor can be considered for women who become postmenopausal during tamoxifen therapy. Information about the value of ovarian suppression continues to emerge, most recently with the demonstration of excellent outcome with goserelin plus tamoxifen in the ABCSG12 trial. The SOFT and TEXT trials, whose accrual is now complete, should help to define optimal endocrine therapy. In addition, use of the 21-gene recurrence score assay may help to delineate the additional value of chemotherapy for patients with node-negative breast cancer, and its utility in the setting of women with 1-3 positive lymph nodes is under study in the RxPONDER trial. Nonetheless, the need for other predictive biomarkers to select appropriate therapy remains real. Finally, attention to long term benefits and side effects of therapy will continue to be vital for these young women.

[Ulipristal acetate (Esmya): a selective modulator of progesterone receptors, new treatment of uterine fibromatosis]

Uterine fibromatosis is a frequent benign gynaecological disease causing heavy menstrual bleeding and in some cases anaemia. Until now, medical treatment aimed to obtain amenorrhea by administration of progestins or Gn-RH agonists. By inducing hypo-oestrogenism, a reduction of myoma size is observed with Gn-RH agonists but after cessation of the treatment, initial myoma size is noted. The impact of progesterone in myoma growth is nowadays demonstrated and use of selective modulators of progesterone receptors represents a new medical approach of this disease.

BAY 1002670: a novel, highly potent and selective progesterone receptor modulator for gynaecological therapies

STUDY QUESTION

Does the novel progesterone receptor (PR) modulator BAY 1002670, based on its preclinical pharmacological profile, offer a potential novel treatment option for uterine fibroids?

SUMMARY ANSWER

The newly synthesized BAY1002670 has proved to be a very potent, highly selective PR modulator in all in vitro and in vivo pharmacodynamics assays performed: it exhibits marked efficacy in an innovative humanized fibroid disease model, suggesting BAY 1002670 to be a very promising treatment option for uterine fibroids.

WHAT IS KNOWN ALREADY

PR inhibiting ligands have shown clinical utility in a range of potential indications and applications. Despite the emergence of the first PR antagonist >30 years ago, no agent of this compound class has been authorized in any indication for long-term application. Among other reasons, suboptimal selectivity and safety profiles of previous candidates have led to discontinuation and modification of development programmes.

STUDY, DESIGN, SIZE, DURATION

The preclinical studies include relevant in vitro and in vivo assays to clarify the properties of the PR modulator BAY 1002670 as well as a fibroid xenograft study to show directly the efficacy of BAY 1002670 on the human target tissue.

PARTICIPANTS/MATERIAL, SETTING, METHODS

BAY 1002670 was tested for binding and transactivational activity towards different human steroid receptors. Activity of the compound in the corresponding in vivo models (rat, rabbit) was assessed. Furthermore, BAY 1002670 was tested in a disease model for uterine fibroids utilizing primary human tumour tissues as xenograft in immunodeficient mice treated with estradiol (E2) and progesterone (P).

MAIN RESULT AND THE ROLE OF CHANCE

BAY1002670 in subnanomolar concentrations exhibits a highly selective binding profile and antagonistic activity for the PR. These properties are also reflected in its action in two progesterone-dependent animal models that assess the termination of pregnancy and endometrial transformation. Favourable selectivity towards other nuclear hormone receptors was demonstrated. No in vivo activity was found at the glucocorticoid, estrogenic and mineralocorticoid receptors with only weak anti-androgenic activity. In a human fibroid xenograft model BAY 1002670 showed a marked dose-dependent reduction of fibroid tumour weight gain of 95% at a dose of 3 mg/kg/day (P < 0.005).

LIMITATIONS AND REASON FOR CAUTION

Selectivity and potency of BAY 1002670 have only been determined in vitro and in animal models so far.

WIDER IMPLICATIONS OF THE FINDING

The PR modulator BAY 1002670 might offer a treatment option not only for uterine fibroids but also for other gynaecological indications.

STUDY FUNDING/COMPETING INTEREST

The studies took place at Bayer Pharma AG. All authors are employees of Bayer Pharma AG. No external funding declared.

Emergency contraception

There have been numerous attempts to control fertility after unprotected sexual intercourse (UPSI). From very bizarre methods like the vaginal application of Coca Cola to the more serious attempts using calcium antagonists influencing fertility parameters in sperm to hormonal methods or intrauterine devices. So far, hormonal methods preventing or delaying ovulation have proved to be the most popular starting with the combination of ethinyl estradiol and levonorgestrel (LNG), known as the Yuzpe regimen. The first dose had to be taken within 72 hours of UPSI, a second one 12 hours later. Later on, LNG alone, at first in a regimen similar to the Yuzpe method (2 × 0.75 mg 12 hours apart) showed to be more successful, eventually resulting in the development of a 1.5 mg LNG pill that combined good efficacy with a high ease of use. Several efficacious and easy to use methods for emergency contraception (EC) are available on the market today with the most widely spread being LNG in a single dose of 1.5 mg (given as one tablet of 1.5 mg or 2 tablets of 0.75 mg each) for administration up to 3 days (according to WHO up to 5 days) after UPSI. Its limitations are the non-optimal efficacy which is decreasing the later the drug is taken and the fact that it is only approved for up to 72 hours after UPSI. This regimen has no effect on the endometrium, corpus luteum function and implantation, is not abortive and don't harm the fetus if accidentally taken in early pregnancy. It has no impact on the rate of ectopic pregnancies. It has become the standard method used up to this day in most countries. Since the mid 1970s copper IUDs have been used for EC, which show a high efficacy. Their disadvantages lie in the fact that EC is considered an off label use for most IUDs (not for the GynFix copper IUD in the European Union) and that they might not be acceptable for every patient. Furthermore IUD-insertion is an invasive procedure and it is required trained providers and sterilized facilities. Mifepristone in the dosages of 10 or 25 mg is used with good results as an emergency contraceptive in China for up to 120 hours after UPSI, but has never received any significant consideration in Western countries. While high doses of mifepristone has an effect on endometrial receptivity and will inhibit ovulation if given in the follicular phase and prevent implantation if given in the early luteal phase, low doses such as 10 mg has no impact on the endometrium. Mifepristone does not increase the rate of ectopic pregnancies. The most recent development is the approval of the selective progesterone receptor modulator ulipristal acetate (UPA) in the dosage of 30 mg for EC up to 5 days after UPSI, combining the safe and easy application of the single dose LNG pill with an even higher efficacy. It has shown to be more efficacious than LNG and can be used for up to 120 hours after UPSI; the difference in efficacy is highest for 0-24 hours, followed by 0-72 hours following UPSI. No VTE has been reported following UPA-administration or any progesterone receptor modulator. No effect on endometrium, corpus luteum function and implantation has been observed with doses used for EC. Independent of the substance it should be noted that, if there is a choice, the intake of an oral emergency contraceptive pill should happen as soon as possible after the risk situation. A pre-existing pregnancy must be excluded. Possible contraindications and drug interactions must be considered according to the individual special product informations.

[Metformin--new treatment strategies for gynecologic neoplasms]

Metformin, a drug from the biguanide class, is now one of the most widely used drugs in the treatment of type 2 diabetes. This drug was also used in the treatment of polycystic ovarian syndrome and recent reports indicate the possibility of using this drug in oncology. Latest findings show that metformin has an anticancer effect. Influencing the transduction mechanisms primarily through activation of protein kinase activated by 5'AMP (AMPK) regulates the activity of the AMPK/mTOR signaling pathway. MTOR pathway dysregulation may be a factor in the pathogenesis of various human diseases, especially cancers. Overactivation of mTOR is observed in malignant cells and is associated with their resistance to treatment. It can therefore be concluded that metformin as an inhibitor of mTOR may be a factor that suppresses tumor development. There are also studies showing that metformin prevents the formation of metastases, reducing tumor vasculature and improves the effectiveness of anticancer drugs. The anticancer effect of metformin has been proven in the treatment of colorectal and breast cancer. The current studies reports the positive effects in the treatment of gynecological cancers such as ovarian, endometrial and cervical cancer. Incidence for these tumors in 2009 in Poland was: for ovarian cancer 11.01100000; for endometrial cancer 15.0/100000; for cervical cancer 10.5/100000. Metformin has antitumor activity in monotherapy and also synergistically with other anticancer agents. Metformin has antiproliferative properties; reduces the VEGF levels, causing a reduction in tumor vasculature; causes an increase in progesterone receptor, which increases the response to hormonal therapy; inhibits the expression of glyoxalase I, mediating resistance to chemotherapy; decreases in the concentration of human telomerase; reduces the activity of Akt and Erk kinases, key regulators of metabolism and progression of tumors and also inhibits the formation of metastases.

Endocrine resistance: what do we know?

Adjuvant therapy with antiestrogens targeting estrogen receptor α (ER) signaling prevents disease recurrence in many patients with early-stage ER+ breast cancer. However, a significant number of cases exhibit de novo or acquired endocrine resistance. While other clinical subtypes of breast cancer (HER2+, triple-negative) have disproportionately higher rates of mortality, ER+ breast cancer is responsible for at least as many deaths because it is the most common subtype. Therefore, identifying mechanisms that drive endocrine resistance is a high clinical priority. A large body of experimental evidence indicates that oncogenic signaling pathways underlie endocrine resistance, including growth factor receptor tyrosine kinases (HER2, epidermal growth factor receptor [EGFR], fibroblast growth factor receptor 1/2 [FGFR], insulin-like growth factor-1 receptor [IGF-1R]/ insulin receptor [InsR]), PI3K/AKT/ mTOR, MAPK/ERK, Src, CDK4/CDK6, and ER itself. Combined targeting of ER and such pathways may be the most effective means to combat antiestrogen resistance, and clinical trials testing such strategies show promising results. Herein, we discuss pathways associated with endocrine resistance, biomarkers that may be useful to predict response to targeted agents, and avenues for further exploration to identify strategies for the treatment of patients with endocrine-resistant disease.

Changing concepts: Menopausal hormone therapy and breast cancer

Hormone therapy is still used by millions of women for menopausal symptoms. Concerns regarding hormone therapy and breast cancer were initially based on case reports and retrospective case-control studies. However, recent results from large prospective cohort studies and the Women's Health Initiative (WHI) randomized placebo-controlled hormone therapy trials have substantially changed concepts regarding how estrogen alone and estrogen plus progestin influence breast cancer. The preponderance of observational studies suggested that estrogen alone and estrogen plus progestin both increased the risk of breast cancer, with cancers commonly diagnosed at an early stage. However, substantially different results emerged from the WHI randomized hormone therapy trials. In the WHI trial evaluating estrogen plus progestin in postmenopausal women with an intact uterus, combined hormone therapy statistically significantly increased the risk of breast cancer and hindered breast cancer detection, leading to delayed diagnosis and a statistically significant increase in breast cancer mortality. By contrast, estrogen alone use by postmenopausal women with prior hysterectomy in the WHI trial did not substantially interfere with breast cancer detection and statistically significantly decreased the risk of breast cancer. Differential mammography usage patterns may explain differences between observational study and randomized trial results. In clinical practice, hormone therapy users have mammograms more frequently than nonusers, leading to more and earlier stage cancer detection. By contrast, in the WHI randomized trials, mammogram frequency was protocol mandated and balanced between comparison groups. Currently, the different effects of estrogen plus progestin vs estrogen alone on breast cancer are not completely understood.

Lowering oral contraceptive norethindrone dose increases estrogen and progesterone receptor levels with no reduction in proliferation of breast epithelium: a randomized trial

BACKGROUND

This study was conducted to compare breast epithelial-cell proliferation and estrogen and progesterone receptor levels in women taking one of two oral contraceptives (OCs) containing the same dose of estrogen but different doses of the progestin norethindrone (NET).

STUDY DESIGN

Thirty-three women were randomly assigned 1:1 to one of two OCs with 35-mcg ethinylestradiol (EE2) but different doses of NET - 1 or 0.4 mg. At the end of the active pill phase of the third OC cycle, a breast biopsy was performed and the percentages of epithelial cells of the terminal duct lobular units were measured for Ki67 (MIB1), progesterone receptors A and B (PRA and PRB, respectively), and estrogen receptor α (ERα).

RESULTS

The biopsies from 27 women had sufficient epithelium for analysis. The percentages of cells positive for PRA, PRB and ERα were approximately double with the lower progestin dose (PRA: p=.041; PRB: p=.030; ERα: p=.056). The Ki67 percentage was not reduced with the lower progestin dose (12.5% for 0.4-mg NET vs. 7.8% for 1.0-mg NET).

CONCLUSIONS

The increase in PRA-, PRB- and ERα-positive cells with the 60% lower progestin dose OC appears likely to account for its failure to decrease breast-cell proliferation. This breast-cell proliferation result is contrary to that predicted from the results of lowering the medroxyprogesterone acetate dose in menopausal hormone therapy.

Pharmacology and clinical use of sex steroid hormone receptor modulators

Sex steroid receptors are ligand-triggered transcription factors. Oestrogen, progesterone and androgen receptors form, together with the glucocorticoid and mineralocorticoid receptors, a subgroup of the superfamily of nuclear receptors. They share a common mode of action, namely translating a hormone-i.e. a small-molecule signal-from outside to changes in gene expression and cell fate, and thereby represent "natural" pharmacological targets.For pharmacological therapy, these receptors have originally been addressed by hormones and synthetic hormone analogues in order to overcome pathologies related to deficiencies in the natural ligands. Another major use for female sex hormone receptor modulators is oral contraception, i.e. birth control.On the other side, blocking the activity of sex steroid receptors has become an established way to treat hormone-dependent malignancies, such as breast and prostate cancer.In this review, we will discuss how the experience gained from the classical pharmacology of these receptors and their molecular similarities led to new options for the treatment of gender-specific diseases and highlight recent progress in medicinal chemistry of sex hormone-modulating drugs.

[The role of estrogen receptor alpha in breast cancer cell proliferation mediated by progestins]

In C4-HD murine mammary carcinomas and in human breast cancer T47D cells, we showed that medroxyprogesterone acetate (MPA) induces a nuclear physical association between estrogen receptor alpha (ERa) and progesterone receptors (PR). The blockade of ERa inhibits cell proliferation mediated by progestins. We hypothesized that this nuclear association between ERa/PR is necessary to trigger progestin-induced cell proliferation and tumor growth. We demonstrated that fulvestrant (FUL, ICI182.780) induced complete regression of C4-HD tumors growing with progestins. MPA treatment induced an early increase in both CCND1 and MYC expression in T47D cells. The blockade of ERa prevented the MPA-dependent transcription of both genes. Specific binding of PR/ERa was observed at the same MPA-sensitive regions at the CCND1 and MYC gene promoters after chromatin immunoprecipitation (ChIP) analysis. ICI inhibited binding of ERa to both gene regulatory sequences while PR binding was unaffected. The nuclear colocalization between both receptors in T47D cells was confirmed by: confocal microscopy, Duolink assays and co-immunoprecipitation assays. In breast cancer samples we also observed a nuclear interaction between both steroid receptors. Our results indicate that the presence of ERa interacting with activated PR at the CCND1 and MYC promoters is required to trigger progestin-induced gene transcription and cell proliferation in breast cancer cells.

Current and future medical treatments for menometrorrhagia during the premenopause

Excessive menstrual bleeding reflects aberrant angiogenesis, generally due to submucosal myomas and endometrial polyps, although it is also frequently observed with long-term progestin-only contraception, impaired haemostasis and hormonal disorders. Surgery (hysterectomy, endometrial ablation) is used too frequently. Uterine artery embolisation is also an option for myomas. Medical treatments include combined oral contraception, progestins and levonorgestrel-releasing Intrauterine System. Gonadotropin-releasing hormone agonists provide significant improvements in bleeding for myomas, but also decrease estrogen secretion (e.g. hot flushes, decreased bone mass). Progestins, although used widely, remain poorly effective as they promote myoma cell growth. Recently, Selective Progesterone Receptor Modulators (SPRMs) have been shown to induce amenorrhea whilst maintaining endogenous estrogen secretion. Phase II studies have also demonstrated decreased fibroid size in SPRM-treated women. Although the mechanism of amenorrhea observed after SPRM treatment is still poorly understood, they may control uterine bleeding via a direct effect on endometrial blood vessels. Suppression of bleeding in women with uterine fibroids receiving SPRMs is associated with moderate reductions in uterine artery blood flow, without major changes in angiogenic factors and extracellular matrix composition; a clear difference to modifications observed with progestins. These data suggest major progress in the treatment of excessive menstrual bleeding.

Differential regulation of endogenous pro-inflammatory cytokine genes by medroxyprogesterone acetate and norethisterone acetate in cell lines of the female genital tract

BACKGROUND

Medroxyprogesterone acetate (MPA) and norethisterone (NET) and its derivatives are widely used in female reproductive therapy, but little is known about their mechanisms of action via steroid receptors in the female genital tract. MPA used as a contraceptive has been implicated in effects on local immune function. However, the relative effects of progesterone (Prog), MPA and norethisterone acetate (NET-A) on cytokine gene expression in the female genital tract are unknown.

STUDY DESIGN

Using two epithelial cell lines generated from normal human vaginal (Vk2/E6E7) and ectocervical (Ect1/E6E7) cells as in vitro cell culture model systems for mucosal immunity of the female cervicovaginal environment, we investigated steroid receptor expression and activity as well as regulation of cytokine/chemokine genes by MPA and NET-A, as compared to the endogenous hormone Prog.

RESULTS

We show that the Prog, androgen, glucocorticoid and estrogen receptors (PR, AR, GR and ER, respectively) are expressed in both the Vk2/E6E7 and Ect1/E6E7 cell lines, and that the GR and AR are transcriptionally active. This study is the first to show ligand-, promoter- and cell-specific regulation of IL-6, IL-8 and RANTES (regulated-upon-activation, normal T cell expressed and secreted) gene expression by Prog, MPA and NET-A in these cell lines. Moreover, we show that the repression of the TNF-α-induced RANTES gene by MPA in the Ect1/E6E7 cell line is mediated by the AR.

CONCLUSION

Collectively, these data demonstrate that cell lines from different anatomical sites of the female genital tract respond differently to Prog and the synthetic progestins, most likely due to differential actions via different steroid receptors. The results highlight the importance of choice of progestins for immune function in the cervicovaginal environment. They further suggest that choice of progestins in endocrine therapy may have implications for women's risk of susceptibility to infections due to differential actions on genes involved in inflammation and immune function.

Indian Hedgehog and its targets in human endometrium: menstrual cycle expression and response to CDB-2914

CONTEXT

Progesterone is critical for secretory endometrial differentiation in women, but its downstream mediators are poorly understood.

OBJECTIVE

Our objective was to investigate endometrial expression of Indian Hedgehog (IHH) and genes involved in its signaling [smoothened (SMO), patched-1 (PTCH1), glioma-associated oncogene homolog 1 (GLI1), and GLI2] during the menstrual cycle and the effects of the selective progesterone receptor modulator CDB-2914 on its expression.

DESIGN AND SETTING

Comparisons between normally cycling volunteers and women with symptomatic fibroids who received CDB-2914 or placebo were made at a clinical research center.

PATIENTS AND INTERVENTIONS

Endometrial biopsy was performed on 34 volunteers, 17 additional women with fibroids.

MAIN OUTCOME MEASURES

Endometrial expression of IHH, SMO, PTCH1, GLI1, and GLI2 by in situ hybridization and/or RT-PCR and IHH, GLI1, and PTCH1 immunohistochemistry were evaluated.

RESULTS

RT-PCR showed expression of IHH, SMO, PTCH1, GLI1, and GLI2, with significant increases in IHH (5.2-fold) and GLI1 (3.6-fold) in endometrium exposed to CDB-2914 compared with placebo. In situ hybridization showed IHH mRNA expression in glands and stroma that was stronger in secretory samples. Among volunteers, IHH and GLI1 immunohistochemistry scores were higher in the secretory than proliferative phase in the nuclei and cytoplasm of glands and stroma (P=0.0002-0.04). Compared with follicular-phase controls, women exposed to CDB-2914 showed increased IHH expression in all compartments except stromal cytoplasm (P=0.0199-0.0423); GLI1 was up-regulated in glandular nuclei and cytoplasm compared with both volunteers and women receiving placebo (P≤0.0416).

CONCLUSIONS

The temporal increase in endometrial IHH and GLI1 during the secretory phase, and their modulation by CDB-2914, suggests progestin regulation and a potential role in endometrial differentiation and implantation.

Randomized placebo-controlled trial of CDB-2914 in new users of a levonorgestrel-releasing intrauterine system shows only short-lived amelioration of unscheduled bleeding

BACKGROUND

The levonorgestrel-releasing intrauterine system (LNG-IUS) is a highly effective contraceptive. However, during early months of use unscheduled vaginal bleeding is common, sometimes leading to discontinuation. This study aimed to determine whether intermittent administration of progesterone receptor modulator CDB-2914 would suppress unscheduled bleeding during the first 4 months after insertion of the LNG-IUS.

METHODS

CDB-2914 150 mg, in divided doses, or placebo tablets, were administered over three consecutive days starting on Days 21, 49 and 77 after LNG-IUS insertion, in a double-blind randomized controlled trial of women aged 19-49 years, newly starting use of LNG-IUS. Daily bleeding diaries were completed for 6 months, and summarized across blocks as percentage days bleeding/spotting (BS%).

RESULTS

Of 69 women randomized to receive CDB-2914, and 67 placebo, 61 and 55, respectively, completed the trial. BS% decreased with time in both arms, but showed a much steeper treatment-phase gradient in the placebo arm (P < 0.0001), so that a benefit of CDB-2914 in the 28 days after first treatment (-11% points, 95% CI -19 to -2), converted to a disadvantage by 64 days after the third treatment (+10% points, 95% CI 1-18).

CONCLUSIONS

The effect of CDB-2914 on BS% was initially beneficial but then by third treatment was disadvantageous. Nevertheless, only 3% (4/136) of all women discontinued LNG-IUS. These findings give insight into possible mechanisms and suggest future research directions. ISRCTN Trial no. ISRCTN58283041; EudraCT no. 2006-006511-72.

[Effect of previous diabetes therapy on tumor receptor phenotype in breast cancer: comparison of metformin and sulphonylurea derivatives]

According to some existing data, unlike sulphonylurea (SU) and insulin derivatives, treatment with biguanide metformin, for reasons still unknown, may diminish breast cancer (BC) morbidity in diabetic females. For its part, diabetes is known to worsen survival of BC patients although there is no evidence of a pathway by which antidiabetic therapy might influence the key prognostic feature of BC tissue--the tumor receptor phenotype. Combination of BC and diabetes (n=90) was studied. SU drugs were received for at least 12 months by 22 patients, biguanide metformin alone or in conjunction with SU by 15, insulin by 5, and dietary treatment alone--by 48 pts. Percentage of estrogen receptor-positive tumors did not vary significantly from group to group. However, progesterone receptor-positive (PR+) tumors in metformin-treated patients were revealed more often than in those receiving SU alone (p = 0.43) or with insulin (p = 0.041), respectively. Hence, previous treatment with metformin is expected lead to higher incidence of PR+ tumors which in turn may stimulate efficiency of hormonal therapy only in relevant group of diabetic BC patients.

The prostate growth stimulation by progesterone is due to androgenic products and progesterone receptor-mediated mechanisms

The antiprogestin mifepristone has been demonstrated to inhibit the growth of R3327HI rat prostatic carcinoma. A comparable antitumor effect of onapristone (ON) on rat Dunning tumors was found in our laboratories. We found the localization of progesterone (P4) receptors (PR) in prostate and prostatic tumors. These findings suggest the involvement of P4 in the mechanism of hormone-dependent growth of prostate and tumors. To study the influence of P4 on the growth of ventral (VP) and dorsolateral prostate (DLP), orchiectomized rats were treated (s.c.) daily with P4 (0.3, 1.0, 3.0 or 10.0 mg), dihydrotestosterone (DHT, 0.05 mg), estradiol (E2, 3.0 microg), ON (3.0 mg), ICI 182780 (1.0 mg) or flutamide (FL, 3.0 mg) for 12 days. One day after the last treatment, animals were sacrificed, and the organ weight of VP and DLP was determined. P4 increased the organ weight of VP and DLP in a dose-dependent manner. In contrast to DHT, which preferentially stimulated the growth of VP, P4 led rather to an increase in the weight of DLP. The effect of P4 on the DLP was enhanced by a simultaneous application of DHT or E2. The antiprogestin ON and the pure antiestrogen ICI 182780 had no appreciable effect on the P4-induced growth of VP and DLP. ON inhibited, however, the E2/P4-induced growth of DLP without affecting the growth of the VP. In contrast the antiandrogen FL suppressed the stimulatory effect of P4 on both the VP and DLP. These findings suggest that the stimulatory effect of P4 on the rat DLP may be partly due to androgenic products derived from P4 and may be also mediated by PR.

The differences in neuroprotective efficacy of progesterone and medroxyprogesterone acetate correlate with their effects on brain-derived neurotrophic factor expression

Whereas hormone therapy is used for the treatment of menopausal symptoms, its efficacy in helping reduce the risk of other diseases such as Alzheimer's disease has been questioned in view of the results of recent clinical trials that appeared inconsistent with numerous basic research studies that supported the beneficial effects of hormones. One possible explanation of this discrepancy may lie in the choice of hormone used. For example, we and others found that progesterone is neuroprotective whereas medroxyprogesterone acetate (MPA), the synthetic progestin used in hormone therapy, is not. Because our data suggest that progesterone-induced protection is associated with the induction of brain-derived neurotrophic factor (BDNF) levels and, importantly, can be blocked by inhibiting the neurotrophin signaling, we determined whether progesterone and medroxyprogesterone acetate differed in their ability to regulate BDNF levels in the explants of the cerebral cortex. We found that progesterone elicited an increase in both BDNF mRNA and protein levels, whereas medroxyprogesterone acetate did not. Furthermore, using both a pharmacological inhibitor of the progesterone receptor (PR) and PR knockout mice, we determined that the effects of progesterone were mediated by the classical PR. Our results underscore the fact that not all progestins have equivalent effects on the brain and suggest that the selection of the appropriate progestin may influence the success of hormone therapy formulations used in treating the menopause and/or reducing the risk for diseases associated with the postmenopausal period.

Gene polymorphisms that may influence the biological effects of progestins

Many of the biological actions of progestins depend on binding to intracellular receptors and through a long chain of events to subsequent stimulation of transcriptional activity and protein synthesis. This process requires at least a few hours in time and many different proteins called coregulators do play a role after binding to the receptor. Evidence for polymorphisms in the gene coding for the PR has been obtained and many studies have already attempted to show associations between particular polymorphisms and human diseases. However, at present no consistent and conclusive picture has emerged on clinically important associations. Studies on links between polymorphisms in genes coding for coregulators are just beginning. The second pathway, the so-called non-genomic actions, is related to rapid effects of progestins that occur within minutes. At this moment a number of different membrane bound receptors have been identified. No data are available yet on polymorphisms in genes coding for these proteins or to link any of these membrane receptors to specific human pathology.

Effect of progesterone on HLA-E gene expression in JEG-3 choriocarcinoma cell line

PROBLEM

Among class Ib human leukocyte antigen (HLA) molecules, HLA-E is known to be a major ligand of CD94/NKG2 receptor on natural killer (NK) cells, and to play a pivotal role in recognition of extravillous trophoblasts (EVTs) by maternal immune cells. However, it is scarcely known how HLA-E expression is regulated in EVTs.

METHOD OF STUDY

In this study, we investigated whether progesterone, an essential hormone in maintaining pregnancy, regulated HLA-E expression in EVT-like cell line, JEG-3. HLA-E mRNA amount in cultured JEG-3 cells was assessed by real-time PCR and cell-surface HLA-E protein was analyzed by flowcytometry.

RESULTS

Real-time PCR showed 3.5-fold increase 1 hour after the addition of 1000 ng/ml progesterone. This response was diminished by the addition of RU486, an antagonist for progesterone receptor. Flowcytometry indicated that 1000 ng/ml progesterone slightly enhanced HLA-E expression on the surface of JEG-3.

CONCLUSION

These results suggest that progesterone up-regulates HLA-E expression in JEG-3 cells through the pathway mediated by progesterone receptor. Our findings might give a new insight into immunomodulatory function of progesterone at fetomaternal interface.

Bioconversion of norethisterone, a progesterone receptor agonist into estrogen receptor agonists in osteoblastic cells

A number of clinical studies have demonstrated that norethisterone (NET), a potent synthetic progestin, restores postmenopausal bone loss, although its mode of action on bone cells is not fully understood, while the effect of naturally occurring progesterone in bone has remained controversial. A recent report claims that the potent effects of NET on osteoblastic cell proliferation and differentiation, mimicking the action of estrogens, are mediated by non-phenolic NET derivatives. To determine whether osteoblasts possess the enzymes required to bioconvert a progesterone receptor (PR) agonist into A-ring reduced metabolites with affinity to bind estrogen receptor (ER), we studied the in vitro metabolism of [(3)H]-labeled NET in cultured neonatal rat osteoblasts and the interaction of its metabolic conversion products with cytosolic -osteoblast ER, employing a competition analysis. Results indicated that NET was extensively bioconverted (36.4%) to 5 alpha-reduced metabolites, including 5 alpha-dihydro NET, 3 alpha,5 alpha-tetrahydro NET (3 alpha,5 alpha-NET) and 3beta,5 alpha-tetrahydro NET (3beta,5 alpha-NET), demonstrating the activities of 5 alpha-steroid reductase and two enzymes of the aldo-keto reductases family. Expression of Srd5a1 in neonatal osteoblast was well demonstrated, whereas Srd5a2 expression was not detected. The most striking finding was that 3beta,5 alpha-NET and 3 alpha,5 alpha-NET were efficient competitors of [(3)H]-estradiol for osteoblast ER binding sites, exhibiting affinities similar to that of estradiol. The results support the concept that the interplay of 5 alpha-steroid reductase and aldo-keto reductases in osteoblastic cells, acting as an intracrine modulator system is capable to bioconvert a PR agonist into ER agonists, offering an explanation of the molecular mechanisms NET uses to enhance osteoblastic cell activities.

Progestin signaling through an olfactory G protein and membrane progestin receptor-alpha in Atlantic croaker sperm: potential role in induction of sperm hypermotility

Progestin stimulation of sperm hypermotility remains poorly understood despite having been described in numerous vertebrate species. We show here that progestin stimulation of sperm hypermotility in a teleost, the Atlantic croaker (Micropogonias undulatus) is associated with activation of an olfactory G protein (Golf). Furthermore, we provide evidence that this progestin action is mediated by membrane progestin receptor-alpha (mPRalpha). Golf was identified in croaker sperm membranes and was specifically activated after treatment with the progestin 17,20beta,21-trihydroxy-4-pregnen-3-one (20beta-S). Treatment of sperm membranes with 20beta-S caused an increase in cAMP production, which was blocked by pretreatment with cholera toxin and two membrane adenylyl cyclase inhibitors: 2',5'-dideoxyadenosine and SQ22536. Moreover, preincubation of croaker sperm with 2',5'-dideoxyadenosine and SQ22536 resulted in a significant inhibition of 20beta-S-stimulated hypermotility. Binding of [3H]20beta-S to sperm membranes was decreased after pretreatment with GTPgammaS but not pertussis toxin, suggesting the receptor is coupled to a pertussis toxin-insensitive G protein. Golf and mPRalpha were coexpressed on the sperm midpiece and flagella and were coimmunoprecipitated from sperm membranes. Finally, expression of mPRalpha protein on sperm increased after in vivo treatment with LHRH and was associated with increased induction of sperm motility by 20beta-S. These results suggest that 20beta-S activates mPRalpha in croaker sperm, which in turn activates Golf and membrane adenylyl cyclase to stimulate sperm hypermotility. Taken together these findings provide a plausible mechanism by which progestins stimulate sperm hypermotility in croaker and provide the first evidence of hormonal activation of Golf in any species.