Potent, nonsteroidal selective androgen receptor modulators (SARMs) based on 8H-[1,4]oxazino[2,3-f]quinolin-8-ones

A series of androgen receptor modulators based on 8H-[1,4]oxazino[2,3-f]quinolin-8-ones was synthesized and evaluated in an androgen receptor transcriptional activation assay. The most potent analogues from the series exhibited single-digit nanomolar potency in vitro. Compound 18h demonstrated full efficacy in the maintenance of muscle weight, at 10 mg/kg, with reduced activity in prostate weight in an in vivo model of androgen action.

Progesterone receptor modulators and the endometrium: changes and consequences

Progesterone receptor modulators (PRMs) have been used for contraceptive research, as well as for treatment of fibroids, endometriosis and heavy or irregular menstrual bleeding. Long-term treatment with these compounds results in changes to the endometrium resulting in potential confusion in trying to characterize endometrial biopsies. A meeting was held to discuss the properties of PRMs, the effects of perturbed hormonal control of the endometrium and the need for further understanding of the biology of progesterone receptor action to facilitate the development of new PRMs. A panel of pathologists was convened to evaluate endometrial changes associated with a minimum of three months of chronic treatment with PRMs. Four different agents were used in the treatment regimens but the pathologists were blinded to treatment regimen or agent. The panel agreed that the endometrial biopsies did not fit into a classification of either proliferative or secretory endometrium but exhibited an unusual architecture that could be characterized as glandular dilatation. There was little evidence of mitosis, consistent with a proposed anti-proliferative effect of PRMs. The panel concluded that the biopsies did not reveal evidence of safety concern and that pathologists and investigators familiar with endometrial effects of chronic PRM exposure should consider working with pharmaceutical companies and regulatory agencies to develop standard descriptions of PRM-associated endometrial changes as well as the types of histologic changes that would signal a need for intervention.

Drospirenone increases endothelial nitric oxide synthesis via a combined action on progesterone and mineralocorticoid receptors

BACKGROUND

Progestins have actions on the cardiovascular system, which depend on the structure as well as on receptor binding characteristics. Drospirenone (DRSP) is a progestin that uniquely interferes with the signaling of the mineralocorticoid receptor (MR). Hormone therapy containing DRSP results in blood pressure reduction in hypertensive post-menopausal women.

METHODS

We describe the effects of DRSP on endothelial nitric oxide (NO) synthesis and compare them with those of progesterone (P) and of medroxyprogesterone acetate (MPA). In addition, we herein tested the relevance of the anti-mineralocorticoid activity of DRSP for NO synthesis.

RESULTS

DRSP results in rapid activation of the endothelial NO synthase (eNOS) through mitogen-activated protein kinases and phosphatidylinositol 3-kinase as well as in enhanced eNOS expression. These actions depend on P receptor. When the cells are exposed to aldosterone, a reduction of eNOS expression is found that is antagonized by DRSP. This action is not shared by P or MPA. In addition, DRSP does not interfere with the induction or activation of eNOS induced by estradiol, as opposed to MPA.

CONCLUSIONS

DRSP acts on endothelial cells via a combined action through the P and MRs. These results help to interpret the anti-hypertensive effects of hormonal therapies containing DRSP.

Progestins and neuroprotection: are all progestins created equal?

Our understanding of the biology of gonadal steroids has expanded such that we now appreciate that the effects of gonadal steroid hormones, including estradiol and progesterone, extend beyond the strict confines of reproductive function and exert their effects on a wide range of tissue targets including, but not limited to, the bone, the heart and the brain. With respect to the brain, an increasing body of literature supports the protective effects of estradiol and progesterone. However, results from the Women's Health Initiative (WHI) underscored the fact that there may be important caveats to these protective effects and include the choice of hormone used. Here, we describe our current understanding of the neurobiology of progesterone and the synthetic progestin used in most formulations of hormone therapy, medroxyprogesterone acetate, and provide a review of the basic and clinical literature that address the importance of progestins in neuroprotection. In addition, we caution that the effects and mechanisms underlying the neurobiological effects of progestins may not be identical to those seen in non central nervous systems. And though additional research is certainly needed to explore the neurobiology of progesterone and its related progestins more completely, we provide evidence that, at least with respect to the brain, not all progestins are created equal.

Effects of levonorgestrel-releasing IUS and progesterone receptor modulator PRM CDB-2914 on uterine leiomyomas

We have found that the use of levonorgestrel-releasing IUS results in a remarkable decrease in endometrial proliferation and a remarkable increase in apoptosis in the endometrium; therefore, it is effective for long-term management of menorrhagic women with uterine myomas because of the striking reduction in menorrhagia. This prompted us to characterize the effects of progesterone (P(4)) and progesterone receptor modulator (PRM) CDB2914 on uterine myoma growth. In vitro studies with cultured uterine leiomyoma cells and normal myometrial cells revealed that P(4) stimulated the proliferative activity in leiomyoma cells, but not in normal myometrial cells. P(4) increased EGF expression, whereas E(2) augmented EGF-R expression in leiomyoma cells, indicating that P(4) and E(2) act in combination to stimulate leiomyoma cell growth. P(4) also increased Bcl-2 expression and decreased TNF-alpha expression in those cells. Unlike the EGF expression, IGF-I expression in leiomyoma cells was inhibited by P(4). These results suggest that P(4) has dual actions on leiomyoma growth: one is to stimulate the growth through up-regulating EGF and Bcl-2 expression, and the other is to inhibit the growth through down-regulating IGF-I expression in the cells. By contrast, CDB2914 inhibited proliferation and stimulated apoptosis of leiomyoma cells without affecting normal myometrial cells. Furthermore, CDB2914 inhibited vascular endothelial growth factor and adrenomedullin expression in leiomyoma cells, but not in normal myometrial cells. The cell type-specific action of CDB2914 on leiomyoma cells, without affecting the surrounding normal myometrial cells, is meaningful for understanding the usefulness of CDB2914 in the medical treatment of uterine myomas.

Evaluation of ER and Ki-67 proliferation index as prognostic factors for survival following neoadjuvant chemotherapy with doxorubicin/docetaxel for locally advanced breast cancer

BACKGROUND

The aim of the study was to identify reliable predictive biological markers for treatment outcome following neoadjuvant adriamycin/docetaxel (AT) chemotherapy in locally advanced breast cancer patients.

MATERIALS AND METHODS

This study was a phase II study on AT neoadjuvant chemotherapy in locally advanced breast cancer patients. Patients received 50 mg/m(2) of doxorubicin intravenously (IV) over 15 min followed by docetaxel 75 mg/m(2) infused over 1 h, repeated every 3 weeks for three cycles. Surgery was performed within 3-4 weeks following the last cycle of chemotherapy. We analyzed the pre-treatment and post-treatment expression levels of ER, PgR, HER-2, Ki-67 proliferation index, and p53 and examined the correlation between the markers and clinical parameters with treatment response, overall survival and relapse-free survival following neoadjuvant treatment.

RESULTS

From July 2001 to September 2004, 61 patients were enrolled. The meaningful parameters adversely influencing survival were post-treatment ER(-) status (P = 0.013) and post-treatment Ki-67 index above 1.0% (P = 0.013). At the multivariate level, the post-treatment Ki-67 proliferation index < or = 1.0 was the only meaningful prognostic factor for better survival (P = 0.033). Notably, tumors with Ki-67 index < or = 1.0 were more likely to express ER with statistical significance (P = 0.002). Tumors with ER(+) and Ki-67 index < or = 1.0 showed the highest survival rate, followed by ER(+) and Ki-67 index > 1.0%, ER(-) and Ki-67 < or = 1.0%, and ER(-) and Ki-67 > 1.0% with the worst survival (P = 0.033).

CONCLUSION

Collectively, post-treatment ER status and Ki-67 proliferation index were prognostic of overall survival following neoadjuvant AT chemotherapy.

Effects of estradiol with micronized progesterone or medroxyprogesterone acetate on risk markers for breast cancer in postmenopausal monkeys

The addition of the synthetic progestin medroxyprogesterone acetate (MPA) to postmenopausal estrogen therapy significantly increases breast cancer risk. Whether this adverse effect is specific to MPA or characteristic of all progestogens is not known. The goal of this study was to compare the effects of oral estradiol (E2) given with either MPA or micronized progesterone (P4) on risk biomarkers for breast cancer in a postmenopausal primate model. For this randomized crossover trial, twenty-six ovariectomized adult female cynomolgus macaques were divided into social groups and rotated randomly through the following treatments (expressed as equivalent doses for women): (1) placebo; (2) E2 (1 mg/day); (3) E2 + P4 (200 mg/day); and (4) E2 + MPA (2.5 mg/day). Hormones were administered orally, and all animals were individually dosed. Treatments lasted two months and were separated by a one-month washout period. The main outcome measure was breast epithelial proliferation, as measured by Ki67 expression. Compared to placebo, E2 + MPA resulted in significantly greater breast proliferation in lobular (P < 0.01) and ductal (P < 0.01) epithelium, while E2 + P4 did not. Intramammary gene expression of the proliferation markers Ki67 and cyclin B1 was also higher after treatment with E2 + MPA (P < 0.01) but not E2 + P4. Both progestogens significantly attenuated E2 effects on body weight, endometrium, and the TFF1 marker of estrogen receptor activity in the breast. These findings suggest that oral micronized progesterone has a more favorable effect on risk biomarkers for postmenopausal breast cancer than medroxyprogesterone acetate.

A Structural and in Vitro Characterization of Asoprisnil: A Selective Progesterone Receptor Modulator

Selective progesterone receptor modulators (SPRMs) have been suggested as therapeutic agents for treatment of gynecological disorders. One such SPRM, asoprisnil, was recently in clinical trials for treatment of uterine fibroids and endometriosis. We present the crystal structures of progesterone receptor (PR) ligand binding domain complexed with asoprisnil and the corepressors nuclear receptor corepressor (NCoR) and SMRT. This is the first report of steroid nuclear receptor crystal structures with ligand and corepressors. These structures show PR in a different conformation than PR complexed with progesterone (P4). We profiled asoprisnil in PR-dependent assays to understand further the PR-mediated mechanism of action. We confirmed previous findings that asoprisnil demonstrated antagonism, but not agonism, in a PR-B transfection assay and the T47D breast cancer cell alkaline phosphatase activity assay. Asoprisnil, but not RU486, weakly recruited the coactivators SRC-1 and AIB1. However, asoprisnil strongly recruited the corepressor NCoR in a manner similar to RU486. Unlike RU486, NCoR binding to asoprisnil-bound PR could be displaced with equal affinity by NCoR or TIF2 peptides. We further showed that it weakly activated T47D cell gene expression of Sgk-1 and PPL and antagonized P4-induced expression of both genes. In rat leiomyoma ELT3 cells, asoprisnil demonstrated partial P4-like inhibition of cyclooxygenase (COX) enzymatic activity and COX-2 gene expression. In the rat uterotrophic assay, asoprisnil demonstrated no P4-like ability to oppose estrogen. Our data suggest that asoprisnil differentially recruits coactivators and corepressors compared to RU486 or P4, and this specific cofactor interaction profile is apparently insufficient to oppose estrogenic activity in rat uterus.

Myometrial progesterone responsiveness

Progesterone actions in human pregnancy are controlled by the extent of myometrial progesterone responsiveness. Current progress in unraveling the biochemistry for myometrial progesterone responsiveness at the genomic and nongenomic levels have lead to novel hypotheses regarding the role of these pathways in the hormonal control of human pregnancy and parturition. For the genomic pathway, progesterone interacts with the type-B nuclear progesterone receptor (nPR-B), which decreases expression of contraction-associated genes. For the nongenomic pathway, progesterone interacts with membrane-associated PRs (mPRs) to modulate directly intracellular Ca2+ and cyclic adenosine monophosphate (cAMP) levels. During most of human pregnancy the genomic and nongenomic pathway cooperate to maintain myometrial relaxation. However, at parturition the relaxing actions of progesterone are nullified by changes in myometrial progesterone responsiveness. This occurs by (1) increased expression of the nPR variants (e.g., PR-A and/or PR-C) and changes in nPR coregulator levels that together repress the transcriptional activity of PR-B; and (2) increased expression of specific mPRs, especially mPRss, which augments contractility by decreasing intracellular cAMP. Functional progesterone withdrawal may be induced by locally produced prostaglandins that alter myometrial nPR expression. This may be an important physiological link between the control of parturition and the immune/inflammatory process.

Analysis of the Pathologic Response to Primary Chemotherapy in Patients with Locally Advanced Breast Cancer Grouped According to Estrogen Receptor, Progesterone Receptor, and HER2 Status

PURPOSE

In clinical practice, it is possible to classify breast tumors according to estrogen receptor (ER), progesterone receptor (PgR), and HER2 overexpression: ER negative, PgR negative, and HER2 overexpressing; ER negative, PgR negative, and HER2 negative; ER positive, PgR positive, and HER2 negative; ER positive, PgR positive, and HER2 overexpressing; and the less frequent remaining 4 combinations. The aim of this study was to determine the percentage of pathologic complete response (pCR) in patients with locally advanced breast cancer (LABC) treated with neoadjuvant or primary chemotherapy with anthracyclines and taxanes grouped according to ER, PgR, and HER2 status.

PATIENTS AND METHODS

Patients with LABC treated with primary chemotherapy including anthracyclines and taxanes were grouped according to ER, PgR, and HER2 status; pCR rates were analyzed using the chi(2) test; and correlations with a P value of < or = 0.05 were considered statistically significant.

RESULTS

A total of 103 patients were treated. Only 100 patients were included for the analysis of pCR. Eighteen patients exhibited pCR. The pCR rate for each subgroup was as follows: 39.1% (9 of 23) had ER-negative, PgR-negative, and HER2-negative disease (P < 0.01); 35.7% (5 of 14) had ER-negative, PgR-negative, and HER2-overexpressing disease; 33.3% (3 of 9) had ER-positive, PgR-positive, and HER2-overexpressing disease; and 2.8% (1 of 36) had ER-positive, PgR-positive, and HER2-negative disease (P < 0.01).

CONCLUSION

In patients with LABC, grouping breast tumors according to ER, PgR, and HER2 status can help predict pCR to primary chemotherapy.

The effects of the selective progesterone receptor modulator asoprisnil on the morphology of uterine tissues after 3 months treatment in patients with symptomatic uterine leiomyomata

BACKGROUND

Asoprisnil is a selective progesterone receptor modulator with mixed progesterone agonist/antagonist activity which controls uterine bleeding via an endometrial effect. This study examined full-thickness endometrial, leiomyoma and myometrial morphology in hysterectomy specimens from patients with uterine leiomyomata, after treatment with asoprisnil for 3 months.

METHODS

In this double-blind, randomized, placebo-controlled study, 33 subjects with uterine leiomyomata were randomized to receive asoprisnil 10, 25 mg or placebo for an average of 95 days prior to hysterectomy. Samples of endometrium, myometrium and leiomyoma tissue were subjected to systematic morphological assessment with quantification of mitotic activity.

RESULTS

In patients treated with 10 or 25 mg asoprisnil, a unique pattern called 'non-physiologic secretory effect' was evident in endometrium, recognizable through partially developed secretory glandular appearances and stromal changes. Endometrial thickness was decreased, and there were low levels of mitotic activity in endometrial glands and stroma. Unusual thick-walled muscular arterioles and prominent aggregations of thin-walled vessels were present in endometrial stroma, but not in myometrium or non-endometrial vascular beds. Mitotic activity was decreased in leiomyomata.

CONCLUSIONS

Asoprisnil induces unique morphological changes and is associated with low levels of glandular and stromal proliferation in endometrium, and in leiomyomata. These changes are likely to contribute to the amenorrhoea experienced after exposure to the medication.

Characterisation of the pharmacological profile of desoxymethyltestosterone (Madol), a steroid misused for doping

Desoxymethyltestosterone (DMT), also known as Madol, is a steroid recently identified to be misused as a doping agent. Since, the knowledge of functions of this substance is rather limited, it was our aim to characterise the pharmacological profile of DMT and to identify potential adverse side effects. DMT was synthesised, its purity was confirmed and its biological activity was tested. The potency of Madol (DMT) to transactivate androgen receptor (AR) dependent reporter gene expression was two times lower as compared to dihydrotestosterone (DHT). Receptor binding tests demonstrate that DMT binds with high selectivity to the AR, binding to the progesterone receptor (PR) was low. In vivo experiments in orchiectomised rats demonstrated that treatment with DMT resulted only in a stimulation of the weight of the levator ani muscle; the prostate and seminal vesicle weights remained unaffected. Like testosterone, administration of DMT resulted in a stimulation of IGF-1 and myostatin mRNA expression in the gastrocnemius muscle. In the prostate proliferation was stimulated by TP (testosteronepropionate), but remained unaffected by DMT. Remarkably, treatment with DMT, in contrast to TP, resulted in a significant increase of the heart weight. In the liver, DMT slightly stimulates the expression of the tyrosine aminotransferase gene (TAT). Our results demonstrate that DMT is a potent AR agonist with an anabolic activity. Besides the levator ani weight, DMT also modulates the gene expression in the musculus gastrocnemius. The observed stimulation of TAT expression in the liver and the significant increase of the heart weight after DMT treatment can be taken as an indication for side effects. Summarizing these data it is obvious that DMT is a powerful anabolic steroid with selective androgen receptor modulators (SARM) like properties and some indications for toxic side effects. Therefore, there is a need for a strict control of a possible misuse.

A randomized, controlled trial of asoprisnil, a novel selective progesterone receptor modulator, in women with uterine leiomyomata

OBJECTIVE

To determine efficacy and safety of asoprisnil in patients with leiomyomata.

DESIGN

Phase 2, multicenter, prospective, randomized, double-blind, placebo-controlled, parallel-group study.

SETTING

Twenty-eight sites in the United States and 1 in Canada.

PATIENT(S)

One hundred twenty-nine women with leiomyomata.

INTERVENTION(S)

Asoprisnil (5, 10, or 25 mg) or placebo orally daily for 12 weeks.

MAIN OUTCOME MEASURE(S)

Uterine bleeding changes by using daily bleeding diaries, hemoglobin concentrations, dominant leiomyoma and uterus volume measured sonographically, patient-reported symptoms related to bloating and pelvic pressure, endometrial thickness and morphology, hormonal parameters, and standard safety measures.

RESULT(S)

Asoprisnil suppressed uterine bleeding in 28%, 64%, and 83% of subjects at 5, 10, and 25 mg, respectively, and reduced leiomyoma and uterine volumes. Median percentage decrease from baseline in leiomyoma volume was statistically significant at 25 mg compared with placebo after 4 and 8 weeks of treatment; by week 12, leiomyoma volume was reduced by 36%. There was a significant reduction in bloating with the two highest doses and in pelvic pressure with 25 mg by week 12. Asoprisnil was associated with follicular-phase estrogen concentration and minimal hypoestrogenic symptoms.

CONCLUSION(S)

After 12-week treatment, asoprisnil controlled uterine bleeding while reducing leiomyoma volume and the associated pressure symptoms. Asoprisnil was well tolerated.

Progesterone inhibits mature rat dendritic cells in a receptor-mediated fashion

A variety of extraimmune system factors, including hormones, play a critical role in regulating immunity. Progesterone has been shown to affect immunity in rodents and humans, mainly at concentrations commensurate with pregnancy. These effects are primarily mediated via the progesterone receptor (PR), which acts as a transcription factor, although non-genomic effects of PR activation have been reported. In this study, we evaluated the effects of progesterone on rat dendritic cells (DCs) at ranges encompassing physiologic and pharmacologic concentrations to determine whether progesterone plays a role in modulating DC-mediated immune responses. DCs were derived by culturing rat bone marrow cells in granulocyte macrophage colony-stimulating factor and IL-4. Cells were analyzed for expression of PR using FACS analysis, real-time reverse transcriptase-PCR and fluorescent microscopy. Progesterone treatment of LPS-activated, mature bone marrow-derived dendritic cells (BMDCs) suppressed production of the pro-inflammatory response-promoting cytokines tumor necrosis factor-alpha and IL-1beta in a dose-dependent manner but did not affect production of the pro-inflammatory response-inhibiting cytokine IL-10. Treatment of cells with progesterone also resulted in down-regulation of co-stimulatory molecule CD80 and MHC class II molecule RT1B expression. In addition, progesterone inhibited DC-stimulated proliferation of T cells. Suppression of pro-inflammatory response-promoting cytokine production by progesterone was prevented using the PR antagonist RU486. There was no dose-dependent effect of progesterone treatment on immature DC capacity to take up antigenic peptide. These data indicate that progesterone directly inhibits mature rat BMDC capacity to drive pro-inflammatory responses. This mechanism could contribute to or account for some of the differential expression of autoimmune/inflammatory disease in females.

α-Methyltryptamine sulfonamide derivatives as novel glucocorticoid receptor ligands

Alpha-methyltryptamine sulfonamides were identified as human glucocorticoid receptor (hGR) ligands in an ultra high throughput screening (UHTS) campaign. Described will be the hit-to-lead activities, including parallel and single point analog synthesis to map the scaffold. Ligands were identified that exhibited 30 nM binding to hGR. The SAR and selectivity of these compounds will be discussed.

In vitro and in vivo characterization of a novel nonsteroidal, species-specific progesterone receptor modulator, PRA-910

The progesterone receptor (PR) is an important regulator of female reproduction. Consequently, PR modulators have found numerous pharmaceutical utilities in women's reproductive health. In the process of identifying more receptor-specific and tissue-selective PR modulators, we discovered a novel nonsteroidal, 6-aryl benzoxazinone compound, PRA-910, that displays unique in vitro and in vivo activities. In a PR/PRE reporter assay in COS-7 cells, PRA-910 shows potent PR antagonist activity with an IC50 value of approximately 20 nM. In the alkaline phosphatase assay in the human breast cancer cell line T47D, PRA-910 is a partial progesterone antagonist at low concentrations and is also an effective PR agonist at higher concentrations (EC50 value of approximately 700 nM). PRA-910 binds to the human PR with high affinity (Kd = 4 nM) and was previously shown to exhibit greater than 100-fold selectivity for the PR versus other steroid receptors. In the adult ovariectomized rat, PRA-910 is a potent PR antagonist. It inhibits progesterone-induced uterine decidual response with an ED50 value of 0.4 mg/kg, p.o., and reverses progesterone suppression of estradiol-induced complement C3 expression with potency similar to RU-486. In the nonhuman primate, however, PRA-910 is a PR agonist. The effect on endometrial histology strongly resembles that of progesterone. This unique compound also suppresses estradiol-induced epithelial cell proliferation and both estrogen and progesterone receptor expression in the uterine endometrium as a PR agonist would. In summary, PRA-910 is a structurally and biologically novel selective PR modulator with either PR agonist or antagonist activity, depending on context, concentration, and species.

The activities of progesterone receptor isoform A and B are differentially modulated by their ligands in a gene-selective manner

It is known that progesterone receptor (PR) isoform A (PR-A) and isoform B (PR-B) may mediate different effects of progesterone. The objective of this study was to determine if the functions of PR isoforms also vary in response to different PR modulators (PRM). The effects of 7 synthetic PRM were tested in MDA-MB-231 cells engineered to express PR-A, PR-B, or both PR isoforms. The effects of progesterone were similar in cells expressing PR-A or PR-B in which it inhibited growth and induced focal adhesion. On the other hand, synthetic PRM modulated the activity of the PR isoforms differently. RU486, CDB4124, 17alpha-hydroxy CDB4124 and VA2914 exerted agonist activities on cell growth and adhesion via PR-B. Via PR-A, however, these compounds displayed agonist effect on cell growth but induced stellate morphology which was distinct from the agonist's effect. Their dual properties via PR-A were also displayed at the gene expression level: the compounds acted as agonists on cell cycle genes but exhibited antagonistic effect on cell adhesion genes. Introduction of ERalpha by adenoviral vector to these cells did not change PR-A or PR-B mediated effect of PRM radically, but it causes significant cell rounding and modified the magnitudes of the responses to PRM. The findings suggest that the activities of PR isoforms may be modulated by different PRM through gene-specific regulatory mechanisms. This raises an interesting possibility that PRM may be designed to be PR isoform and cellular pathway selective to achieve targeted therapy in breast cancer.

Progesterone receptors activation after acute cocaine administration

Cocaine modulates serum levels of progesterone in intact female and male rats, as well as in pregnant dams, and progesterone decreases or attenuates cocaine-induced behavioral and reward responses. It has been postulated that cocaine's modulation of serum progesterone levels may in turn alter progesterone receptor activity, thereby contributing to cocaine-induced alterations of neuronal functions and genomic regulations. To test this hypothesis, intact male rats received acute injections of saline or cocaine (15 or 30 mg/kg, dissolved in 0.9% saline, intraperitoneal). Progesterone serum levels, progesterone receptor (PR) protein levels, and PR-DNA binding complexes were measured in the striatum by radioimmunoassay, Western blot, and gel shift analyses, respectively. After injection of 15 mg/kg of cocaine, induction of progesterone serum levels was closely followed by an increase in receptor protein levels and DNA binding complexes. After injection of 30 mg/kg of cocaine, similar effects were observed along with an attenuation of receptor protein levels and DNA binding complexes at 60 min. Our results suggest that activation of progesterone receptors may be a mechanism by which cocaine mediates behavior through molecular alterations in the central nervous system.

In Vitro and In Vivo Evaluation of the Estrogenic, Androgenic, and Progestagenic Potential of Two Cyclic Siloxanes

The purpose of these experiments was to determine the potential estrogenic, androgenic, and progestagenic activity of two cyclic siloxanes, octamethylcyclotetrasiloxane (D4) and decamethylcyclopentasiloxane (D5). Receptor-binding experiments and a luciferase reporter gene assay were used to determine if the materials were able to bind and activate either the estrogen receptors (ERs) or progesterone receptors (PRs)-alpha or beta. The rat uterotrophic assay (RUA) for estrogenic activity and the Hershberger assay for androgenic activity were utilized as the in vivo assays. For the ER-binding studies, D4 was shown to bind to ERalpha but not to ERbeta. D5 did not bind to either of the two receptors. D4 activated the reporter gene at 10 microM, while D5 was considered negative in the estrogen reporter gene assay. Neither material was a ligand for the PRs. Both the RUA and Hershberger assays were conducted using whole-body inhalation of the two materials for 16 h/day. D4 resulted in a small but significant increase in both wet and blotted uterine weight as well as increases in both luminal and glandular epithelial cell height in both Sprague Dawley and Fischer 344 rats. D5 was negative in both rat strains, indicating that D5 does not possess estrogenic activity. Neither material possessed any significant antiestrogenic activity. Both materials were negative in the Hershberger assay indicating that neither material possesses any significant androgenic activity. Our studies have shown that D4 exhibits a low affinity for ERalpha in vitro and a weakly estrogenic response in vivo.

Differences in the glucocorticoid to progesterone receptor selectivity of inhaled glucocorticoids

Due to the high affinity of new inhaled corticosteroids (ICS) towards the glucocorticoid receptor (GR), and because of the similarities between the binding domains of the GR and the progesterone receptor (PR), the present study focused on assessing the relative binding affinities (RBA) of glucocorticoids (systemic and ICS) to PR (RBAPR). By comparison with the affinities towards the GR (RBAGR) the binding selectivities were also assessed. In general, the selectivity of the investigated glucocorticoids showed a decreasing trend with increasing lipophilicity. When orally administered, less lipophilic glucocorticoids showed the highest selectivity, with RBAGR/RBAPR ratios of 1,375, 760 and 476 for betamethasone, beclomethasone and dexamethasone, respectively. For ICS, mometasone furoate, the most lipophilic steroid, was the least selective (1.1), followed by beclomethasone monopropionate (9), fluticasone propionate (12), triamcinolone acetonide (18), mometasone (25) and budesonide (44), which shows the highest selectivity among inhaled glucocorticoids. In conclusion, the present study revealed that there are differences in selectivity among commercially available glucocorticoids. Future clinical studies are needed to investigate whether the high affinity of some of the investigated glucocorticoids to the progesterone receptor is of clinical relevance.

The enantiomer of progesterone acts as a molecular neuroprotectant after traumatic brain injury

Previous work shows that neurosteroid enantiomers activate specific molecular receptors that relay neuroprotection. However, the actions of the enantiomer of progesterone (ent-PROG) at the PROG receptor (PR) are unknown. PR binding and transcriptional assays were performed to determine the actions of ent-PROG at the classical PR. Additionally, the neuroprotective effects of ent-PROG in traumatic brain injury (TBI) were investigated and compared to the actions of PROG and its metabolite allopregnanolone (ALLO), both of which have been shown to have neuroprotective properties when given after TBI. Binding studies performed in COS cells over-expressing the PR showed that ent-PROG inhibited PROG binding to the PR. In contrast, ent-PROG did not activate PR-mediated transcription. Rats received bilateral medial frontal cortex injury followed by treatments at 1, 6, 24 and 48h with PROG, ALLO or ent-PROG. Brains were processed for edema, protein and enzyme activity. ent-PROG treatment in vivo decreased cerebral edema, cell death mediators, inflammatory cytokines, and reactive gliosis, and increased antioxidant activity. These findings suggest that the progestin-mediated pro-survival response seen with TBI is regulated either independently of the classical PR or via nongenomic PR-regulated actions.

BRCA1 and BRCA2 mutation carriers, oral contraceptive use, and breast cancer before age 50

BACKGROUND

Understanding the effect of oral contraceptives on risk of breast cancer in BRCA1 or BRCA2 mutation carriers is important because oral contraceptive use is a common, modifiable practice.

METHODS

We studied 497 BRCA1 and 307 BRCA2 mutation carriers, of whom 195 and 128, respectively, had been diagnosed with breast cancer. Case-control analyses were conducted using unconditional logistic regression with adjustments for family history and familial relationships and were restricted to subjects with a reference age under 50 years.

RESULTS

For BRCA1 mutation carriers, there was no significant association between risk of breast cancer and use of oral contraceptives for at least 1 year [odds ratio (OR), 0.77; 95% confidence interval (95% CI), 0.53-1.12] or duration of oral contraceptive use (P(trend) = 0.62). For BRCA2 mutation carriers, there was no association with use of oral contraceptives for at least 1 year (OR, 1.62; 95% CI, 0.90-2.92); however, there was an association of elevated risk with oral contraceptive use for at least 5 years (OR, 2.06; 95% CI, 1.08-3.94) and with duration of use (OR(trend) per year of use, 1.08; P = 0.008). Similar results were obtained when we considered only use of oral contraceptives that first started in 1975 or later.

CONCLUSIONS

We found no evidence overall that use of oral contraceptives for at least 1 year is associated with breast cancer risk for BRCA1 and BRCA2 mutation carriers before age 50. For BRCA2 mutation carriers, use of oral contraceptives may be associated with an increased risk of breast cancer among women who use them for at least 5 years. Further studies reporting results separately for BRCA1 and BRCA2 mutation carriers are needed to resolve this important issue.

Gonadotropin-induced expression of messenger ribonucleic acid for cyclooxygenase-2 and production of prostaglandins E and F2alpha in bovine preovulatory follicles are regulated by the progesterone receptor

Follicular production of prostaglandins (PGs) is essential for ovulation, but the factors mediating gonadotropin-induced secretion of PGE and PGF(2alpha) remain largely unknown. We tested the hypothesis that gonadotropin-induced changes in progesterone and its receptor (PR) mediate the increase in periovulatory PGs. Heifers were treated with PGF(2alpha) and GnRH to induce luteolysis and the LH/FSH surge (ovulation occurs approximately 30 h after GnRH). Because there are two increases in intrafollicular progesterone/PR mRNA during the bovine periovulatory period, we first examined the temporal pattern of PG production by follicles collected at 0, 3.5, 6, 12, 18, and 24 h after GnRH. Although PGs did not increase in the follicular fluid until 24 h after GnRH, acute secretion of PGs by follicle wall (theca + granulosa cells) was initiated by 18 h and had increased manyfold by 24 h after GnRH. In vitro, FSH and LH induced dramatic transient increases in PG production by follicle wall and granulosa, but not theca, cells isolated from preovulatory follicles (0 h after GnRH). PG accumulation peaked on d 2 of culture, mimicking the secretion pattern after a gonadotropin surge in vivo. In cultures of follicle wall and granulosa cells, the PR antagonist mifepristone (MIFE, 1 microm) inhibited LH-induced PG secretion and the progestin medroxyprogesterone acetate (1 or 10 microm), but not the glucocorticoid dexamethasone (1 or 10 microm), overcame the effect of MIFE on PGs. Semiquantitative RT-PCR revealed that MIFE inhibited LH-induced expression of cyclooxygenase-2 mRNA in granulosa cells in vitro. Again, treatment with medroxyprogesterone acetate overcame the effect of MIFE. Together these results provide strong evidence that periovulatory increases in cyclooxygenase-2 mRNA, PGE, and PGF(2alpha) are mediated by gonadotropin-induced increases in progesterone/PR, indicating that in some species there is an important functional relationship between these pathways in the ovulatory cascade.

Ginsenoside Re, a main phytosterol of Panax ginseng, activates cardiac potassium channels via a nongenomic pathway of sex hormones

Ginseng root is one of the most popular herbs throughout the world and is believed to be a panacea and to promote longevity. It has been used as a medicine to protect against cardiac ischemia, a major cause of death in the West. We have previously demonstrated that ginsenoside Re, a main phytosterol of Panax ginseng, inhibits Ca(2+) accumulation in mitochondria during cardiac ischemia/reperfusion, which is attributable to nitric oxide (NO)-induced Ca(2+) channel inhibition and K(+) channel activation in cardiac myocytes. In this study, we provide compelling evidence that ginsenoside Re activates endothelial NO synthase (eNOS) to release NO, resulting in activation of the slowly activating delayed rectifier K(+) current. The eNOS activation occurs via a nongenomic pathway of each of androgen receptor, estrogen receptor-alpha, and progesterone receptor, in which c-Src, phosphoinositide 3-kinase, Akt, and eNOS are sequentially activated. However, ginsenoside Re does not stimulate proliferation of androgen-responsive LNCaP cells and estrogen-responsive MCF-7 cells, implying that ginsenoside Re does not activate a genomic pathway of sex hormone receptors. Fluorescence resonance energy transfer experiments with a probe, SCCoR (single cell coactivator recruitment), indicate that the lack of genomic action is attributable to failure of coactivator recruitment. Thus, ginsenoside Re acts as a specific agonist for the nongenomic pathway of sex steroid receptors, and NO released from activated eNOS underlies cardiac K(+) channel activation and protection against ischemia-reperfusion injury.