Endocrine pharmacological characterization of progesterone antagonists and progesterone receptor modulators with respect to PR-agonistic and antagonistic activity

Next step in the development of mesoprogestins: the preclinical profile of EC313

Introduction

The pharmacological target for progesterone, different progestins, and Selective Progesterone Receptor Modulators (SPRMs) is the nuclear progesterone receptor (PR). EC313 is a new member of a subgroup of SPRMs, mesoprogestins, which combine especially PR- agonistic and PR-antagonistic activities in one molecule.

Methods

The suitable in vivo-model for the differentiation of SPRMs from the subgroup of mesoprogestins is the estrogen-primed juvenile rabbit endometrium assay (McPhail Assay). Remarkably, in contrast to other well-known SPRMs with no agonistic effects in this test, EC313 shows clear partial PR-agonistic effects that are higher than that of the well-known mesoprogestin Asoprisnil which already demonstrated remarkable clinical effectiveness for the treatment of uterine fibroids and endometriosis. The findings from the guinea pig studies presented here can be the impetus for further preclinical development of EC313. This model shows the same features for the termination of pregnancy by antiprogestins such as Mifepristone and Ulipristal acetate (UPA) in humans. Moreover, it is possible to distinguish between progestational and anti-progestational activities in the same experiment.

Results

The EC313 treatment reveals PR dominance in the genital tract and inhibits unopposed estrogenic effects. In very high doses (30.0 mg/animal/day subcutaneously (s.c.)) given twice on pregnancy days 43 and 44, no premature labor was induced (in contrast to UPA, dosed at 10.0 and 30. mg/animal/day s.c.). The anti-ovulatory activity of EC313 exceeds that of Ulipristal acetate or Mifepristone. EC313 binds to the steroid receptors in vitro with a similar affinity as the natural ligand progesterone. At the glucocorticoid receptor (GR) EC313 acts as a weak inhibitor. Minor activities at the human androgen receptor (AR) and mineralocorticoid receptor (MR) are considered negligible. No binding to the estradiol receptor was detected. In contrast to some in vitro-receptor findings, estrogenic, anti-estrogenic, androgenic, anti-androgenic, glucocorticoid, and anti-glucocorticoid actions were absent in vivo. The tissue selectivity of EC313 was demonstrated previously by reducing the growth and proliferation of uterine fibroids in animal models (lowest effective dosage 0.1 mg/kg/day s.c.).. As shown in this article, the anti-fibroid activity of EC313 was confirmed with a 10 times lower dosage (0.01 mg/kg/day s.c.). It was also shown that EC313 reduces the growth of endometriotic lesions in a human xenograft immune-deficient (NOD-SCID) mice model with a comparatively very low dosage range. In the aforementioned EC313 activity model, UPA was tested as the reference compound, the clinical effectiveness of which has already been demonstrated.

Discussion

For an explanation of these findings, the possibility is discussed that the mixed agonistic/antagonistic feature of EC313 is tissue target-specific based on its super-additive synergism characteristic for active bifunctional agents. In conclusion, the specific pharmacodynamic profile of this compound opens the possibility for the development of a drug with a distinct pharmaco-endocrinological profile against uterine fibroids, endometriosis, and other PR-dependent gynecological diseases.

Contemporary approaches in the management of uterine leiomyomas

BACKGROUND

Leiomyomas (fibroids), the most common benign solid tumours in females, originate from the myometrium and are associated with poor quality of life for patients. The current management of uterine leiomyomas mainly includes surgical interventions such as hysterectomy and myomectomy, either by laparoscopy or laparotomy, which have several complications and are not ideal for preserving fertility. Therefore, there is a need to develop or repurpose medical treatments that do not require surgical intervention.

OBJECTIVE

Many drugs are used to treat the symptoms associated with uterine fibroids. The main objective of this systematic review is to give an up-to-date account of potential pharmacological agents (non-surgical methods) for the management of uterine leiomyomas.

SEARCH STRATEGY

PubMed was searched for scientific and clinical literature using the keyword 'uterine fibroids' along with the drug names described in each section. For example, 'uterine fibroids' and 'ulipristal acetate' were the keywords used to search for literature on ulipristal acetate (UPA).

RESULTS

Various preclinical and clinical studies have shown that some drugs and herbal formulations exhibit activity in the management of uterine leiomyomas. Recent studies found that drugs such as UPA, elagolix, EC313, asoprisnol, nutritional supplements and herbal preparations were helpful in treating the symptoms associated with uterine leiomyomas.

CONCLUSION

Many drugs show efficacy in patients with symptomatic uterine fibroids. UPA is one of the most studied and prescribed medicines for uterine fibroids; however, its usage has been restricted due to a few recent incidences of hepatic toxicity. Herbal drugs and natural supplements have also shown promising effects on uterine fibroids. The synergistic effects of nutritional and herbal supplements have been reported in certain cases, and should be studied in detail. Further research is warranted to identify the mode of action of the drugs, and to determine the precise conditions that would explain the causes of toxicity in some patients.

Onapristone Extended Release: Safety Evaluation from Phase I-II Studies with an Emphasis on Hepatotoxicity

Introduction

Antiprogestins have demonstrated promising activity against breast and gynecological cancers, but liver-related safety concerns limited the advancement of this therapeutic class. Onapristone is a full progesterone receptor antagonist originally developed as an oral contraceptive and later evaluated in phase II studies for metastatic breast cancer. Because of liver enzyme elevations identified during clinical studies, further development was halted. Evaluation of antiprogestin pharmacology and pharmacokinetic data suggested that liver enzyme elevations might be related to off-target or metabolic effects associated with clinical drug exposure.

Objective

We explored whether the use of a pharmaceutic strategy targeting efficacious systemic dose concentrations, but with diminished peak serum concentrations and/or total drug exposure would mitigate hepatotoxicity. Twice-daily dosing of an extended-release formulation of onapristone was developed and clinically evaluated in light of renewed interest in antiprogestin therapy for treating progesterone receptor-positive breast and gynecologic cancers. The hepatotoxic potential of extended-release onapristone was assessed from two phase I–II studies involving patients with breast, ovarian, endometrial, and prostate cancer.

Results

Among the 88 patients in two phase I–II studies in progesterone receptor-positive malignancies treated with extended-release onapristone, elevated alanine aminotransferase/aspartate aminotransferase levels were found in 20% of patients with liver metastases compared with 6.3% without metastases. Of five patients with grade 3 or higher alanine aminotransferase elevations with or without bilirubin elevations (four with breast cancer and one with endometrial cancer), four were assessed as unrelated to extended-release onapristone by the safety data review committee. Furthermore, while the fifth patient’s liver enzyme elevations were considered possibly drug related by the study investigator, they were adjudicated as unlikely to be related (< 25% likelihood) by a subsequent independent hepatologist.

Conclusions

These results suggest that the extended-release formulation by reducing drug exposure may be associated with a reduced risk of hepatotoxicity, and supports the continued clinical evaluation of extended-release onapristone for treating progesterone receptor-positive cancers.

Asoprisnil, a Selective Progesterone Receptor Modulator (SPRM), Inhibits Melanosome Export in B16F10 Cells and HEMn-DP Melanocytes

Previous studies have reported that estrogen hormone promotes melanogenesis while progesterone inhibits it. A selective estrogen receptor modulator (SERM), tamoxifen, has been shown to promote melanogenesis; however, to date, there have been no reports on the effects of a selective progesterone receptor modulator (SPRM) on melanogenesis. In the present study, we hypothesized that asoprisnil (AP), a SPRM, inhibits melanogenesis. AP was tested for cytotoxicity to B16F10 mouse melanoma cells for screening the nontoxic concentrations using MTS cytotoxicity assay. Extracellular and intracellular melanin levels were estimated at nontoxic concentrations of AP. To evaluate the direct effect of AP on tyrosinase enzyme, tyrosinase activity and copper chelating activities were measured. Next, the effects of AP on melanogenesis were tested in normal human melanocytes, neonatal, darkly pigmented (HEMn-DP). Our results demonstrate that AP was nontoxic at a concentration range of 10–50 μM in B16F10 cells; AP at 50 μM significantly suppressed extracellular melanin levels comparable to kojic acid at 500 μM, with no significant effect on intracellular melanin levels. The mechanism of melanogenesis inhibition was studied to assess if AP downregulated tyrosinase activity in cell lysates or in a cell-free system. However, AP was found to increase intracellular tyrosinase activity without any effect on tyrosinase enzyme activity or copper chelating activity in a cell-free system, indicating that AP inhibits melanogenesis by mechanisms other than direct effects on tyrosinase enzyme activity. The capacity of AP to inhibit melanosome export was further validated in HEMn-DP cells; AP significantly suppressed dendricity at concentrations of 20 and 30 μM in the absence of effects on melanin synthesis or intracellular tyrosinase activity. In addition, AP was nontoxic to human keratinocytes (HaCaT) at these concentrations, validating its safety for topical use. Taken together, our preliminary results demonstrate that AP might be repurposed as a candidate therapeutic for treatment of hyperpigmentation disorders via a unique mechanism, which encompasses a selective inhibition of melanosome export.

Safety and efficacy of the selective progesterone receptor modulator asoprisnil for heavy menstrual bleeding with uterine fibroids: pooled analysis of two 12-month, placebo-controlled, randomized trials

STUDY QUESTION

Can asoprisnil, a selective progesterone receptor modulator, provide clinically meaningful improvements in heavy menstrual bleeding (HMB) associated with uterine fibroids with an acceptable safety profile?

SUMMARY ANSWER

Uninterrupted treatment with asoprisnil for 12 months effectively controlled HMB and reduced fibroid and uterine volume with few adverse events.

WHAT IS KNOWN ALREADY

In a 3-month study, asoprisnil (5, 10 and 25 mg) suppressed uterine bleeding, reduced fibroid and uterine volume, and improved hematological parameters in a dose-dependent manner.

STUDY DESIGN, SIZE, DURATION

In two Phase 3, double-blind, randomized, placebo-controlled, multicentre studies, women received oral asoprisnil 10 mg, asoprisnil 25 mg or placebo (2:2:1) once daily for up to 12 months.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Premenopausal women ≥18 years of age in North America with HMB associated with uterine fibroids were included (N = 907). The primary efficacy endpoint was the percentage of women who met all three predefined criteria at 12 months or the final month for patients who prematurely discontinued: (1) ≥50% reduction in monthly blood loss (MBL) by menstrual pictogram, (2) hemoglobin concentration ≥11 g/dL or an increase of ≥1 g/dL, and (3) no interventional therapy for uterine fibroids. Secondary efficacy endpoints included changes in other menstrual bleeding parameters, volume of the largest fibroids, uterine volume and health-related quality of life (HRQL).

MAIN RESULTS AND THE ROLE OF CHANCE

In all, 90% and 93% of women in the asoprisnil 10-mg and 25-mg groups, respectively, and 35% of women in the placebo group met the primary endpoint (P < 0.001). Similar results were observed at month 6 (P < 0.001). The percentage of women who achieved amenorrhea in any specified month ranged from 66-78% in the asoprisnil 10-mg group and 83-93% in the asoprisnil 25-mg group, significantly higher than with placebo (3-12%, P < 0.001). Hemoglobin increased rapidly (by month 2) with asoprisnil treatment and was significantly higher versus placebo throughout treatment. The primary fibroid and uterine volumes were significantly reduced from baseline through month 12 with asoprisnil 10 mg (median changes up to -48% and -28%, respectively) and 25 mg (median changes up to -63% and -39%, respectively) versus placebo (median changes up to +16% and +13%, respectively; all P < 0.001). Dose-dependent, significant improvements in HRQL (Uterine Fibroid Symptom and Quality of Life instrument) were observed with asoprisnil treatment. Asoprisnil was generally well tolerated. Endometrial biopsies indicated dose- and time-dependent decreases in proliferative patterns and increases in quiescent or minimally stimulated endometrium at month 12 of treatment. Although not statistically significantly different at month 6, mean endometrial thickness at month 12 increased by ~2 mm in both asoprisnil groups compared with placebo (P < 0.01). This effect was associated with cystic changes in the endometrium on MRI and ultrasonography, which led to invasive diagnostic and therapeutic procedures in some asoprisnil-treated women.

LIMITATIONS, REASONS FOR CAUTION

Most study participants were black; few Asian and Hispanic women participated. The study duration may have been insufficient to fully characterize the endometrial effects.

WIDER IMPLICATIONS OF THE FINDINGS

Daily uninterrupted treatment with asoprisnil was highly effective in controlling menstrual bleeding, improving anemia, reducing fibroid and uterine volume, and increasing HRQL in women with HMB associated with uterine fibroids. However, this treatment led to an increase in endometrial thickness and invasive diagnostic and therapeutic procedures, with potential unknown consequences.

STUDY FUNDING/COMPETING INTEREST(S)

This trial was funded by AbbVie Inc. (prior sponsors: TAP Pharmaceutical Products Inc., Abbott Laboratories). E.A. Stewart was a site investigator in the Phase 2 study of asoprisnil and consulted for TAP during the design and conduct of these studies while at Harvard Medical School and Brigham and Women's Hospital. She received support from National Institutes of Health grants HD063312, HS023418 and HD074711 and research funding, paid to Mayo Clinic for patient care costs related to an NIH-funded trial from InSightec Ltd. She consulted for AbbVie, Allergan, Bayer HealthCare AG, Gynesonics, and Welltwigs. She received royalties from UpToDate and the Med Learning Group. M.P. Diamond received research funding for the conduct of the studies paid to the institution and consulted for AbbVie. He is a stockholder and board and director member of Advanced Reproductive Care. He has also received funding for study conduct paid to the institution from Bayer and ObsEva. A.R.W. Williams consulted for TAP and Repros Therapeutics Inc. He has current consultancies with PregLem SA, Gedeon Richter, HRA Pharma and Bayer. B.R. Carr consulted for and received research funding from AbbVie. E.R. Myers consulted for AbbVie, Allergan and Bayer. R.A. Feldman received compensation for serving as a principal investigator and participating in the conduct of the trial. W. Elger was co-inventor of several patents related to asoprisnil. C. Mattia-Goldberg is a former employee of AbbVie and may own AbbVie stock or stock options. B.M. Schwefel and K. Chwalisz are employees of AbbVie and may own AbbVie stock or stock options.

TRIAL REGISTRATION NUMBER

NCT00152269, NCT00160381 (clinicaltrials.gov).

TRIAL REGISTRATION DATE

7 September 2005; 8 September 2005.

DATE OF FIRST PATIENT’S ENROLMENT

12 September 2002; 6 September 2002.

90 YEARS OF PROGESTERONE: Selective progesterone receptor modulators in gynaecological therapies

Abnormal uterine bleeding (AUB) is a chronic, debilitating and common condition affecting one in four women of reproductive age. Current treatments (conservative, medical and surgical) may be unsuitable, poorly tolerated or may result in loss of fertility. Selective progesterone receptor modulators (SPRMs) influence progesterone-regulated pathways, a hormone critical to female reproductive health and disease; therefore, SPRMs hold great potential in fulfilling an unmet need in managing gynaecological disorders. SPRMs in current clinical use include RU486 (mifepristone), which is licensed for pregnancy interruption, and CDB-2914 (ulipristal acetate), licensed for managing AUB in women with leiomyomas and in a higher dose as an emergency contraceptive. In this article, we explore the clinical journey of SPRMs and the need for further interrogation of this class of drugs with the ultimate goal of improving women's quality of life.

EC313-a tissue selective SPRM reduces the growth and proliferation of uterine fibroids in a human uterine fibroid tissue xenograft model

Uterine fibroids (UFs) are associated with irregular or excessive uterine bleeding, pelvic pain or pressure, or infertility. Ovarian steroid hormones support the growth and maintenance of UFs. Ulipristal acetate (UPA) a selective progesterone receptor (PR) modulator (SPRM) reduce the size of UFs, inhibit ovulation and lead to amenorrhea. Recent liver toxicity concerns with UPA, diminished enthusiasm for its use and reinstate the critical need for a safe, efficacious SPRM to treat UFs. In the current study, we evaluated the efficacy of new SPRM, EC313, for the treatment for UFs using a NOD-SCID mouse model. EC313 treatment resulted in a dose-dependent reduction in the fibroid xenograft weight (p < 0.01). Estradiol (E2) induced proliferation was blocked significantly in EC313-treated xenograft fibroids (p < 0.0001). Uterine weight was reduced by EC313 treatment compared to UPA treatment. ER and PR were reduced in EC313-treated groups compared to controls (p < 0.001) and UPA treatments (p < 0.01). UF specific desmin and collagen were markedly reduced with EC313 treatment. The partial PR agonism and no signs of unopposed estrogenicity makes EC313 a candidate for the long-term treatment for UFs. Docking studies have provided a structure based explanation for the SPRM activity of EC313.

Ligand Binding Induces Agonistic-Like Conformational Adaptations in Helix 12 of Progesterone Receptor Ligand Binding Domain

Progesterone receptor (PR) is a member of the nuclear receptor (NR) superfamily and plays a vital role in the female reproductive system. The malfunction of it would lead to several types of cancers. The understanding of conformational changes in its ligand binding domain (LBD) is valuable for both biological function studies and therapeutically intervenes. A key unsolved question is how the binding of a ligand (agonist, antagonist, or a selective modulator) induces conformational changes of PR LBD, especially its helix 12. We applied molecular dynamics (MD) simulations to explore the conformational adaptations of PR LBD with or without a ligand or the co-repressor peptides binding. From the simulations, both the agonist progesterone (P4) and the selective PR modulator (SPRM) asoprisnil induces agonistic-like helix 12 conformations (the "closed" states) in PR LBD and the complex of LBD-SPRM is less stable, comparing to the agonist-liganded PR LBD. The results, therefore, explain the partial agonism of the SPRM, which could induce weak agonistic effects in PR. We also found that co-repressor peptides could be stably associated with the LBD and stabilize the LBD in a "semi-open" state for helix 12. These findings would enhance our understanding of PR structural and functional relationships and would also be useful for future structure and knowledge-based drug discovery.

Discovery of Vilaprisan (BAY 1002670): A Highly Potent and Selective Progesterone Receptor Modulator Optimized for Gynecologic Therapies

Progesterone plays an important role in the female reproductive system. However, there is also evidence that gynecologic disorders/diseases such as uterine fibroids and endometriosis are progesterone-dependent. Steroidal and non-steroidal selective progesterone receptor modulators (SPRMs) have shown potential for the treatment of such diseases. Steroidal SPRMs, including mifepristone and ulipristal acetate, have proven effective in clinical trials. However, several steroidal SPRMs containing a dimethylamino substituent have been associated with elevated liver enzymes in patients. An earlier drug discovery program identified lonaprisan as a highly selective SPRM that did not show drug-related change in liver enzyme activity. Building on data obtained from that work, here we describe the research program that culminated in the discovery of a novel steroidal SPRM, vilaprisan, which combines an extremely high potency with very favorable drug metabolism and pharmacokinetic properties. Vilaprisan has entered clinical development and is currently undergoing phase 3 clinical trials.

Model for Hormonal Emergency Contraception (HEC) in cycling and mated guinea pigs - Studies with the Progesterone Receptor Modulators (PRM) Ulipristal Acetate (UPA/CDB2914) and EC317

A guinea pig model for new HEC methods is proposed. Two targets for HEC (Hormonal Emergency Contraception), ovulation and conception (post-mating study), were investigated using adjusted PRM treatments: (a) Ovulation inhibition study: Injections on cycle days 10-17, study of ovarian histology on day 18; (b) post-mating study: Injections on cycle days 1 and 2; rate of pregnant females was recorded at autopsy on day 18. P plasma levels permitted assessment of effects on ovulation in non-conceiving animals.

RESULTS

(a) All controls had recently ovulated. Statistically significant anti-ovulatory effects (p < 0.05, Fisher's Exact Test) were seen at 10 mg UPA (ulipristal acetate, CDB2914) and ≥0.3 mg EC317; 100% inhibition was found for EC317 at 10, 3, and 1 mg/day. No dosage of UPA was 100% effective. (b) In post-mating studies, 16 of 30 controls were pregnant. Both PRMs (progesterone receptor modulator) exerted inhibitory effects on conception, none on imminent ovulation; 1 of 10 animals had living conceptuses after 10 mg UPA, none following 10 and 1 mg EC317/day, respectively. At pairwise comparison with controls, 10 mg was the lowest effective dosage for UPA (p < 0.05), and 1 mg for EC317 (p < 0.01). P plasma levels: Significantly lower P (p < 0.05) in subsequently pregnant vs non-pregnant controls was found on cycle day 3 or 4; this difference disappeared on day 8 or 9. This stage thus appears vulnerable to hormonal constellations and possibly PRM effects. HEC model: Effects on ovulation and conception were seen at the same dose levels of both PRM. Superior and more consistent effects of EC317 vs UPA (factor ≥10) suggest higher efficacy using EC317 for HEC.

Optimal routes of administration, vehicles and timing of progesterone treatment for inhibition of delivery during pregnancy

OBJECTIVES

Progestins, notably progesterone (P4) and 17 alpha hydroxyprogesterone caproate, are presently used to treat pregnant women at risk of preterm birth. The aim of this study was to assess the optimal treatment options for progesterone (P4) to delay delivery using a sensitive bioassay for progesterone.

STUDY DESIGN

Pregnant rats, known to be highly sensitive to progestins, were treated with P4, including Prochieve^® (also known as Crinone^®), in various vehicles from day 13 of gestation and in late gestation, days 19 to 22, and delivery times noted. Various routes of administration of P4 and various treatment periods were studied.

RESULTS

Use of micronized P4 by rectal, subcutaneous injection (sc) and topical (transdermal) administration in various oils all significantly (P<0.05-<0.001) delay delivery, but vaginal Prochieve^® did not. Administration of P4 in late gestation also prevented (P<0.001) delivery even when given 8h before delivery.

CONCLUSIONS

Prochieve^® possesses little biological activity to suppress delivery in a sensitive bioassay system and suggests that this preparation may be of little value in prevention and inhibition of preterm birth. Further, this study shows: 1) Inhibition of delivery is increased with P4 treatments when given subcutaneously or topically. 2) P4 in fish oil provides the best vehicle for topical treatment and may be an effective treatment of preterm birth. 3) P4 in fish oil also delays delivery even when treatment begins just prior to normal delivery. 4) To prevent preterm birth in pregnant women, randomized controlled studies are needed with a potent progestin using better formulations and routes of administration.

Summary of Future Developments

Endometriosis is a chronic disease with the potential to cause devastating clinical manifestations such as infertility and chronic pelvic disease. Current treatment is limited to surgical intervention and pharmacologic therapy targeting estrogen and progesterone to suppress ectopic endometrial tissue proliferation. Undesired side effects and contraindications to the use of hormonal medications may reduce treatment options. As the pathogenesis of endometriosis continues to be investigated, new therapies will emerge. The identification of genes involved in the development of endometriosis may allow targeted therapy to prevent or cure disease. In addition, increasing knowledge of the inflammatory pathways that promote ectopic endometrial growth will permit the development of pharmacologic agents to manipulate these signaling pathways. Utilization of selective progesterone receptor modulators, aromatase inhibitors, and modern gonadotropin-releasing hormone antagonists provide more options to manage disease when traditional treatment fails. Individualized therapeutic strategies will soon be a reality as a greater understanding of endometriosis is obtained through the investigation of genomic studies, molecular pathways, and environmental influences.

In vitro-assessment of putative antiprogestin activities of phytochemicals and synthetic UV absorbers in human endometrial Ishikawa cells

Critical steps of embryo implantation are controlled by progesterone. These processes can be interrupted by progesterone receptor (PR) antagonists, e.g. drugs used for abortion. Antiprogestin effects induced by natural compounds and environmental chemicals have been rarely addressed. In our in vitro study, we investigated putative antiprogestin activities of the plant compounds apigenin (API) and trans-ferulic acid (t-FA) as well as the UV absorbers octyl methoxycinnamate (OMC) and 4-methylbenzylidene camphor (4-MBC). They were compared with the selective progesterone receptor modulators (SPRMs) mifepristone (RU486) and ulipristal acetate (UPA) as well as the full PR-antagonist ZK137316. Effects of test compounds in combination with progesterone on the progesterone-sensitive target gene estrogen sulfotransferase (SULT1E1) were characterized by sigmoidal concentration-response curves obtained by RT-qPCR. The agonistic effect of progesterone on SULT1E1 mRNA levels was concentration-dependently antagonized by RU486, UPA and ZK137316 as well as, with lower potency, apigenin. t-FA, OMC and 4-MBC had no effect on SULT1E1 mRNA levels. We demonstrated that apigenin, although at higher concentrations, exerts a similar effect as the well-characterized SPRMs RU486 and UPA or the progesterone antagonist ZK137316 in this model. Our endometrium-specific Ishikawa cell assay is a useful complement to artificial transactivation assays for the identification of environmental substances with antiprogestin activities.

The Effects of Sugammadex on Progesterone Levels in Pregnant Rats

BACKGROUND

Sugammadex has been shown to decrease the efficiency of progesterone-containing oral contraceptive drugs which possess a steroid structure.

AIMS

The aim of the present study was to evaluate the effects of sugammadex on progesterone levels in pregnant rats as well as on the physiological course of the pregnancy.

STUDY DESIGN

Animal experiment.

METHODS

This study was approved by the Selçuk University Ethical Committee for Experimental Animal Research. Pregnant Winster Albino rats (n=26) were divided into three groups and administered with various intravenous injections on the 7(th) day of pregnancy. The control group (Group K, n=6) received 1.5 mL serum physiologic, the sugammadex group (Group S, n=10) received 30 mg/kg sugammadex and the sugammadex + rocuronium group (Group SR, n=10) received 30 mg/kg sugammadex and 3.5 mg/kg rocuronium. Progesterone levels were measured and the offspring were monitored for morphologic status.

RESULTS

Mean progesterone levels were 94.16±15.54 ng/mL in Group K, 87.86±12.48 ng/mL in Group S, and 94.53±16.10 ng/mL in Group SR (p>0.05). No stillbirth or miscarriage was observed in the rats. The mean number of offspring was 6.8±1.47 in Group K, 6.5±1.35 in Group S, and 6.4±1.17 in Group SR. The offspring appeared macroscopically normal.

CONCLUSION

Sugammadex does not appear to affect the progesterone levels in pregnant rats in the first trimester and the clinical course. Successful completion of pregnancy and the absence of stillbirth or miscarriage will guide future studies about the use of sugammadex, particularly in the first trimester of the pregnancy.

Synthesis and biological evaluation of 11' imidazolyl antiprogestins and mesoprogestins

Antiprogestins with a 4' para imidazolylphenyl moiety were synthesized and their biochemical interactions with the progesterone and glucocorticoid receptor were investigated. Depending on the substitution pattern at the 17 position partial progesterone receptor (PR)-agonistic derivatives like compounds EC339 and EC336 or pure antagonists like compound EC317 were obtained. EC317 was investigated in vivo and found to be significantly more potent than RU 486 in cycling and pregnant guinea pigs. For testing the biological action progesterone receptor modulators (PRM), guinea pigs appears as a specific model when compare to pregnant human uterus. This model correlates to human conditions such as softening and widening of the cervix, the elevation of the uterine responsiveness to prostaglandins and oxytocin, and finally to induction of labor. The use of non-pregnant guinea pigs permitted the simultaneous assessment of PR-agonistic and PR-antagonistic properties and their physiological interactions with uterine and vaginal environment. These can histologically be presumed from the presence of estrogen or progesterone dominance in the genital tract tissues. The ovarian histology indicated the effects on ovulation. Corpora lutea in guinea pigs further reflects inhibitory effects of the progesterone-dependent uterine prostaglandin secretion. PRMs are initially synthesized as analogues of RU 486. They represent a heterogeneous group of compounds with different ratios of PR-agonistic and-antagonistic properties. PR-agonistic properties may be essential for uterine anti-proliferative effects. In various clinical studies these were also attributed to RU 486 or Ulipristal [1,2]. Adjusted PR-agonistic PRMs (EC312, EC313) [3] may be more effective in achieving a mitotically resting endometrium and superior uterine tumor inhibition. For the use in termination of pregnancy, progesterone-inhibitory effects are essentially needed. Even minor PR-agonistic properties compromise the therapeutic goals. Pure PR-antagonists, as EC317, clearly exceeded the gold standard RU 486 with respect to labor inducing effects. Mechanistically it is surprising that both types of compound may be potent inhibitors of ovulation.

Potential role of hCG in apoptosis of human luteinized granulosa cells

The corpus luteum (CL) forms after ovulation and acts as a temporary endocrine gland that produces progesterone (P4), a hormone that is essential for implantation and maintenance of pregnancy in mammals. In pregnant women, human chorionic gonadotropin (hCG) secreted by the conceptus prevents luteolysis. hCG also increases the survival of cultured human luteinized granulosa cells (hLGCs). To clarify the maintenance mechanism of the human CL, we investigated the effects of hCG and P4 receptor antagonists, onapristone (OP) and RU486, on the viability of hLGCs. With the patients’ consent, hLGCs were isolated from follicular aspirates for in vitro fertilization. The cells were cultured with hCG (0.1, 1, 10, 100 IU/ml), OP (10, 25, 50, 100 μM), RU486 (100 μM), P4 (1, 10, 25, 50 μM) or some combination of the four for 24 h. Cell viability was significantly increased by hCG (100 IU/ml) and significantly decreased by OP (100 μM) compared with the control. Cells treated with hCG and OP together were significantly less viable than the control and OP-treated cells. The combined treatment also significantly increased CASP3 activity and cleaved CASP3 protein expression. Furthermore, P4 addition reversed the reduction in cell viability caused by the combination of hCG and OP treatment. The overall findings suggest that hCG cooperates with P4 to increase survival of hLGCs and to induce apoptosis when P4 action supported by hCG is attenuated in the human CL.

New and emerging contraceptives: a state-of-the-art review

Background

The first hormonal contraceptive was introduced onto the market in several countries 50 years ago; however, the portfolio of contraceptive methods remains restricted with regards to their steroid composition, their cost, and their ability to satisfy the requirements of millions of women/couples in accordance with their different reproductive intentions, behaviors, cultures, and settings.

Methods

A literature review was conducted using Medline, Embase, and Current Contents databases, up to September 1, 2013 to identify publications reporting new contraceptives in development using combinations of the search terms: contraception, contraceptives, oral contraceptives, patch, vaginal ring, implants, intrauterine contraceptives, and emergency contraception (EC). Also, several experts in the field were also consulted to document ongoing projects on contraception development. Additionally, the Clinicaltrial.gov website was searched for ongoing studies on existing contraceptive methods and new and emerging female contraceptives developed over the past 5 years. Information was also obtained from the pharmaceutical industry.

Results

Early sexual debut and late menopause means that women may require contraception for up to 30 years. Although oral, injectable, vaginal, transdermal, subdermal, and intrauterine contraceptives are already available, new contraceptives have been developed in an attempt to reduce side effects and avoid early discontinuation, and to fulfill women’s different requirements. Research efforts are focused on replacing ethinyl-estradiol with natural estradiol to reduce thrombotic events. In addition, new, less androgenic progestins are being introduced and selective progesterone receptor modulators and new delivery systems are being used. In addition, research is being conducted into methods that offer dual protection (contraception and protection against human immunodeficiency virus transmission), and contraceptives for use “on demand.” Studies are also investigating non-hormonal contraceptive methods that have additional, non-contraceptive benefits.

Conclusion

The most pressing need worldwide is, first, that the highly effective contraceptive methods already available should be affordable to most of the population and also that these methods should fulfill the needs of women of different ages and with different reproductive requirements. The development of new contraceptive methods should also take advantage of the knowledge obtained over the past 30 years on gamete physiology and gamete interaction to avoid the use of steroid compounds.

Synthesis and antiprogestational properties of novel 17-fluorinated steroids

Progesterone receptor (PR) plays a key role in reproductive functions, and compounds that inhibit progesterone action (antiprogestins) have potential use in the treatment of estrogen- and progesterone-dependent diseases, including uterine leiomyomas and breast cancer. In the present study, we chemically synthesized novel 17-fluorinated steroids and evaluated the cytotoxicity profiles of these compounds in T47D breast cancer cells compared to the activity of known antiprogestins, including ZK230 211, RU-486, CDB2914, CDB4124 and ORG33628. We analyzed in vitro receptor-binding assays and PR-transactivation assays to establish the antiprogestational activity of these molecules. The representative antiprogestin EC304 was found to inhibit in vitro tumorigenicity in a dose-dependent fashion in T47D cells by a colony formation assay at 1 and 10nM concentrations. The potent in vivo antiprogestational activity of EC304 was also demonstrated in an antinidation assay for the interruption of early pregnancy in rats. The strong antiprogestational activity and absence of antiglucocorticoid activity in EC compounds may demonstrate their utility in the treatment of leiomyoma, endometriosis and breast cancer.

[Interest of selective progesterone receptor modulators in endometriosis]

The SPRM (selective progesterone receptor modulators) are agonists and/or antagonists of progesterone receptor. They are responsible for anovulation, amenorrhea and a lower prostaglandin levels, which leads to an improvement in pain and regression of lesions in endometriosis. On the endometrium, a particular aspect, the progesterone receptor modulator-associated endometrial changes (PAEC), raises additional studies to verify its harmlessness. However, due to the lack of hypoestrogenism and metabolic effects with these drugs, it is very likely that the SPRM will in the near future an important place in the treatment of endometriosis.

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.

The effects of ulipristal on Bax/Bcl-2, cytochrome c, Ki-67 and cyclooxygenase-2 expression in a rat model with surgically induced endometriosis

OBJECTIVE

To evaluate the effect of ulipristal on Bax/Bcl-2, cytochrome C, Ki-67 and cyclooxygenase-2 expression in surgically induced endometriosis in a rat model.

STUDY DESIGN

We conducted a prospective, randomized, controlled, experimental study at the Experimental Research Center of the Iuliu Hatieganu University of Medicine and Pharmacy in Cluj-Napoca, Romania. Endometriosis was induced in 40 female Wistar albino rats by transplanting two autologous fragments of uterine horn onto bowel mesentery. After a 4-week induction period, we formed two groups: the first group was treated with ulipristal (UPA+) for 8 weeks, while the second group was treated only with the vehicle used for ulipristal (UPA-). We measured the volumes and masses of the implants both before and after treatment. A pathologist examined the sections microscopically for histological hallmarks of endometriosis. Immunostaining for Bax/Bcl-2, cytochrome C, Ki-67 and cyclooxygenase-2 (COX-2) was assessed in both groups.

RESULTS

Ulipristal reduced the average implant volume and mass, indicating that the drug is effective (P=0.01). The treatment induced a greater than 50% reduction in the volume and mass of endometrial implants, and the histological findings correspond to this result. The overall Bax positivity rate was higher in the group treated with ulipristal (42.37% vs. 21.05% for UPA+ and UPA-, respectively) (P=0.0062). The overall Bcl-2 positivity rate was smaller in the group treated with ulipristal (15% vs. 40% for UPA+ and UPA-, respectively) (P=0.0593). The cytochrome C global positivity rate was 5% in the UPA- group and increased to 50% in the UPA+ treatment group (P<0.0001). The COX-2 positivity rate decreased from 75% in the UPA- treatment group to 10% in the UPA+ treatment group (P<0.0001) and the Ki67 positivity rate also decreased from 55% in the UPA- group to 10% in the UPA+ treatment group (P<0.0002).

CONCLUSIONS

Treatment with ulipristal contributed to the regression and atrophy of endometriotic lesions in rats. The immunohistochemical expression profiles of Bax/Bcl-2 and cytochrome C revealed a pro-apoptotic effect of ulipristal. We also observed a reduced cellular proliferation, indicated by a decrease in Ki-67 expression and an anti-inflammatory effect, shown by a decrease in COX-2 expression after treatment with ulipristal.

Induction of the expressions of antioxidant enzymes by luteinizing hormone in the bovine corpus luteum

Luteoprotective mechanisms of luteinizing hormone (LH) involved in the maintenance of bovine corpus luteum (CL) function have not been completely clarified. Since antioxidant enzymes are well documented as antiapoptotic factors in the CL of many mammals, we hypothesized that the luteoprotective action of LH is mediated by stimulating the local production and action of antioxidant enzymes. To test the above hypothesis, in the present study, we examined the mechanisms involved in the luteoprotective actions of LH. Cultured bovine luteal cells obtained from the CL at the mid-luteal stage (days 8–12 of the estrous cycle) were treated with LH (10 ng/ml), onapristone (OP; a specific progesterone receptor antagonist, 100 μM) and diethyldithiocarbamate [DETC; an inhibitor of superoxide dismutase (SOD), 100 μM] for 24 h. LH in combination with or without OP significantly increased the mRNA and protein expressions of manganese SOD (Mn-SOD) and catalase (CATA) and SOD activity. While LH alone significantly increased the mRNA and protein expressions of SOD containing copper and zinc (Cu,Zn-SOD), OP in combination with or without LH significantly decreased the mRNA and protein expressions of Cu,Zn-SOD. In addition, Cu,Zn-SOD, Mn-SOD and CATA mRNA expressions were higher at the mid luteal phase than the other luteal phases. LH in combination with DETC significantly decreased LH-increased cell viability. The overall results suggest that LH increases cell viability by LH-increased antioxidant enzymes, resulting in maintenance of CL function during the luteal phase in cattle.

Synthesis and biological evaluation of partially fluorinated antiprogestins and mesoprogestins

A series of antiprogestins have been synthesized by partially fluorinating the steroid molecule in positions relevant for receptor binding. By introducing fluorine at the exo-methylene of the 17 spirofuran ring, we obtained partial agonists (mesoprogestins) with significant applications for antiproliferative and antiovulatory treatment strategies in gynecological therapy such as uterine fibroids, endometriosis and heavy menstrual bleeding. Compared to the standard drug RU486, our synthesized compounds exhibited considerable dissociation between antiprogestational and antiglucocorticoid PR receptors. Furthermore, our studies have shown that pure antiprogestins can be generated by partially fluorinating the 17 propenyl and propynl group or by substituting the 4' acetyl phenyl group in the 11 position using trifluromethyl group.

Progesterone action in endometrial cancer, endometriosis, uterine fibroids, and breast cancer

Progesterone receptor (PR) mediates the actions of the ovarian steroid progesterone, which together with estradiol regulates gonadotropin secretion, prepares the endometrium for implantation, maintains pregnancy, and differentiates breast tissue. Separation of estrogen and progesterone actions in hormone-responsive tissues remains a challenge. Pathologies of the uterus and breast, including endometrial cancer, endometriosis, uterine fibroids, and breast cancer, are highly associated with estrogen, considered to be the mitogenic factor. Emerging evidence supports distinct roles of progesterone and its influence on the pathogenesis of these diseases. Progesterone antagonizes estrogen-driven growth in the endometrium, and insufficient progesterone action strikingly increases the risk of endometrial cancer. In endometriosis, eutopic and ectopic tissues do not respond sufficiently to progesterone and are considered to be progesterone-resistant, which contributes to proliferation and survival. In uterine fibroids, progesterone promotes growth by increasing proliferation, cellular hypertrophy, and deposition of extracellular matrix. In normal mammary tissue and breast cancer, progesterone is pro-proliferative and carcinogenic. A key difference between these tissues that could explain the diverse effects of progesterone is the paracrine interactions of PR-expressing stroma and epithelium. Normal endometrium is a mucosa containing large quantities of distinct stromal cells with abundant PR, which influences epithelial cell proliferation and differentiation and protects against carcinogenic transformation. In contrast, the primary target cells of progesterone in the breast and fibroids are the mammary epithelial cells and the leiomyoma cells, which lack specifically organized stromal components with significant PR expression. This review provides a unifying perspective for the diverse effects of progesterone across human tissues and diseases.

Utero-placental expression of angiotensin-(1-7) and ACE2 in the pregnant guinea-pig

BACKGROUND

In humans, trophoblast invasion, vascular remodeling and placental development are critical to determine the fate of pregnancy. Since guinea-pigs (GP) and humans share common pregnancy features including extensive trophoblast invasion, transformation of the uterine spiral arteries and a haemomonochorial placenta, the GP animal model was deemed suitable to extend our knowledge on the spatio-temporal immunoreactive expression of the vasodilator arpeptide of the renin-angiotensin system, angiotensin-(1-7) [Ang-(1-7)] and its main generating enzyme, angiotensin converting enzyme 2 (ACE2).

METHODS

Utero-placental units were collected in days 15, 20, 40 and 60 of a 64-67 day long pregnancy in 25 Pirbright GP. Ang-(1-7) and ACE2 expression in utero-placental units were evaluated by immunohistochemistry.

RESULTS

Ang-(1-7) and ACE2 were detected in the endothelium and syncytiotrophoblast of the labyrinthine placenta, interlobium, subplacenta, giant cells, syncytial sprouts, syncytial streamers, and myometrium throughout pregnancy. In late pregnancy, perivascular or intramural trophoblasts in spiral and mesometrial arteries expressed both factors. Immunoreactive Ang-(1-7) and ACE2 were present in decidua and in the vascular smooth muscle of spiral, myometrial and mesometrial arteries, which also express kallikrein (Kal), the bradykinin receptor 2 (B2R), vascular endothelial growth factor (VEGF) and its type 2 receptor (KDR), but no endothelial nitric oxide synthase (eNOS). In addition, the signal of Ang-(1-7) and ACE2 was especially remarkable in giant cells, which also show Kal, B2R. eNOS, VEGF and KDR.

CONCLUSIONS

The spatio-temporal expression of Ang-(1-7) and ACE2 in GP, similar to that of humans, supports a relevant evolutionary conserved function of Ang-(1-7) and ACE2 in decidualization, trophoblast invasion, vascular remodeling and placental flow regulation, as well as the validity of the GP model to understand the local adaptations of pregnancy. It also integrates Ang-(1-7) to the utero-placental vasodilatory network. However, its antiangiogenic effect may counterbalance the proangiogenic activity of some of the other vasodilator components.

In vitro characterization of ZK 230211--A type III progesterone receptor antagonist with enhanced antiproliferative properties

The progesterone receptor (PR) is a key regulator of female reproductive functions. Compounds with progesterone inhibiting effects (PR antagonists) have found numerous utilities in female reproductive health, ranging from contraception to potential treatment of progesterone-dependent diseases like uterine leiomyomas. Based on in vitro characteristics such as DNA binding activity and partial agonistic transcriptional behavior in the presence of protein kinase A activators (cyclic-AMP), three types of PR modulators with antagonistic properties have been defined. In this study, we analyzed the in vitro characteristics of the PR antagonist ZK 230211 in comparison to the classical antagonists onapristone and mifepristone. We focused on PR actions in genomic signaling pathways, including DNA binding activity, nuclear localization and association with the nuclear receptor corepressor (NCoR) as well as actions in non-genomic signaling, such as the activation of c-Src kinase signaling and cyclin D1 gene promoter activity. ZK 230211 represents a type of PR antagonist with increased inhibitory properties in comparison to mifepristone and onapristone. When liganded to the progesterone receptor, ZK 230211 induces a strong and persistent binding to its target response element (PRE) and increases NCoR recruitment in CV-1 cells. Furthermore, ZK 230211 displays less agonistic properties with regard to the association of PR isoform B and the cytoplasmic c-Src kinase in HeLa cells. It represses T47D cell cycle progression, in particular estradiol-induced S phase entry. In summary, our studies demonstrate ZK 230211 to be a type III progesterone receptor antagonist which is characterized by very strong DNA binding activity and strong antiproliferative effects in the cancer cell lines HeLa and T47D.

Intrauterine administration of CDB-2914 (Ulipristal) suppresses the endometrium of rhesus macaques

BACKGROUND

Ulipristal (UPA; CDB-2914) is a progesterone receptor modulator with contraceptive potential. To test its effects when delivered by an intrauterine system (IUS), we prepared control and UPA-filled IUS and evaluated their effects in rhesus macaques.

STUDY DESIGN

Short lengths of Silastic tubing either empty (n=3) or containing UPA (n=5) were inserted into the uteri of 8 ovariectomized macaques. Animals were cycled by sequential treatment with estradiol and progesterone. After 3.5 cycles, the uterus was removed.

RESULTS

During treatment, animals with an empty IUS menstruated for a mean total of 11.66+/-0.88 days, while UPA-IUS treated animals bled for only 1+/-0.45 days. Indices of endometrial proliferation were significantly reduced by UPA-IUS treatment. The UPA exposed endometria were atrophied with some glandular cysts while the blank controls displayed a proliferative morphology without cysts. Androgen receptors were more intensely stained in the glands of the UPA-IUS treated endometria than in the blank-IUS treated controls.

CONCLUSIONS

In rhesus macaques, a UPA-IUS induced endometrial atrophy and amenorrhea. The work provides proof of principle that an IUS can deliver effective intrauterine concentrations of Ulipristal.

Vasodilator factors in the systemic and local adaptations to pregnancy

We postulate that an orchestrated network composed of various vasodilatory systems participates in the systemic and local hemodynamic adaptations in pregnancy. The temporal patterns of increase in the circulating and urinary levels of five vasodilator factors/systems, prostacyclin, nitric oxide, kallikrein, angiotensin-(1-7) and VEGF, in normal pregnant women and animals, as well as the changes observed in preeclamptic pregnancies support their functional role in maintaining normotension by opposing the vasoconstrictor systems. In addition, the expression of these vasodilators in the different trophoblastic subtypes in various species supports their role in the transformation of the uterine arteries. Moreover, their expression in the fetal endothelium and in the syncytiotrophoblast in humans, rats and guinea-pigs, favour their participation in maintaining the uteroplacental circulation. The findings that sustain the functional associations of the various vasodilators, and their participation by endocrine, paracrine and autocrine regulation of the systemic and local vasoactive changes of pregnancy are abundant and compelling. However, further elucidation of the role of the various players is hampered by methodological problems. Among these difficulties is the complexity of the interactions between the different factors, the likelihood that experimental alterations induced in one system may be compensated by the other players of the network, and the possibility that data obtained by manipulating single factors in vitro or in animal studies may be difficult to translate to the human. In addition, the impossibility of sampling the uteroplacental interface along normal pregnancy precludes obtaining longitudinal profiles of the various players. Nevertheless, the possibility of improving maternal blood pressure regulation, trophoblast invasion and uteroplacental flow by enhancing vasodilation (e.g. L-arginine, NO donors, VEGF transfection) deserves unravelling the intricate association of vasoactive factors and the systemic and local adaptations to pregnancy.

Effects of antiprogestins on the uterus

Progesterone-receptor modulators (PRMs) are progesterone-receptor ligands that can exert agonistic, antagonistic or mixed agonist-antagonist effects depending on the cellular context. The mechanisms of action of these compounds are still incompletely understood. PRMs already have several applications in women's health such as emergency contraception, pregnancy termination, management of early fetal demise and cervical maturation. The main indications that will be developed in the future include dysfunctional bleeding and preoperative treatment of uterine myomas. Other future indications may include estrogen-free contraception, treatment of endometriosis and prevention and treatment of breast cancer. However, the available data from mid- to long-term continuous administration studies has raised the issue of endometrial safety. For this reason, long-term applications of PRMs are currently postponed, although windows of treatment with a short course of progestin therapy, or even by a short interruption of treatment, could improve endometrial aspects if needed.

Gynaecological uses of a new class of steroids: the selective progesterone receptor modulators

Selective progesterone receptor modulators (SPRM) represent a new class of synthetic steroids, which can interact with the progesterone receptor (PR) and can exert agonist, antagonist or mixed effects on various progesterone target tissues in vivo. This review evaluates the actual and potential usefulness of SPRMs in gynaecology.

Global gene expression profiling of progesterone receptor modulators in T47D cells provides a new classification system

Progesterone receptor modulators (PRMs) play an important role in women's health. They are widely used in oral contraception or hormone therapy, and provide an attractive treatment approach for gynecological disorders such as uterine leiomyomas, endometriosis or breast cancer. Due to the broad range of activities, various studies were conducted to assess progesterone receptor antagonists (PAs) and selective progesterone receptor modulators (SPRMs) with respect to progesterone receptor (PR) agonistic and antagonistic activities in vivo. These properties are not always adequately reflected in classical in vitro models, especially differences in the agonistic potential of SPRMs, such as asoprisnil, J1042, and J912, and mixed antagonists, such as mifepristone, are not sufficiently substantiated. The effects of PRMs upon gene expression in progesterone target tissues such as breast epithelium and uterus are poorly understood. This study compares the properties of PR ligands using mammalian two-hybrid assays and gene expression profiling. The protein-protein interaction analyses in HeLa cells provide for specific ligand-induced PR conformations, whereas Affymetrix GeneChip HG-U133Plus2.0 analyses in T47D breast cancer cells indicate the transcriptional activity on the level of target genes. The analyses comprise the pure agonist R5020, the non-steroidal PR modulator PRA-910, SPRMs (J1042, asoprisnil, J912), the mixed antagonist mifepristone, classical antagonists (onapristone, ZK 137316) and the pure antagonist lonaprisan to consider all types of ligands described before. Marginal differences were identified in coactivator interaction profiles at all, but significant differences between SPRMs and PR antagonists (PAs) were observed in recruiting the LXXLL-motif containing peptide (LX-H10), very similar to in vivo activities in endometrial transformation in the rabbit (McPhail test). Global gene expression profiles demonstrated progesterone-independent effects for all PR modulators examined and emphasised similarities of asoprisnil and J1042 compared to J912 and all types of PR antagonists. In summary, the data support the popular concept of PR modulator classification in agonists, selective progesterone receptor modulators, mixed and pure antagonists. It further refines previous classification models and accentuates unique effects for each PR modulator.

Effects of the selective progesterone receptor modulator asoprisnil on uterine artery blood flow, ovarian activity, and clinical symptoms in patients with uterine leiomyomata scheduled for hysterectomy

INTRODUCTION

Asoprisnil, a novel orally active selective progesterone receptor modulator, is being studied for the management of symptomatic uterine leiomyomata. The exact mechanism of action is not yet discerned. The primary objectives of this double-blind, randomized, placebo-controlled study included evaluation of the effect of asoprisnil on uterine artery blood flow. Furthermore, we assessed effects of asoprisnil on leiomyoma symptoms.

PATIENTS AND METHODS

Thirty-three premenopausal patients scheduled for hysterectomy due to symptomatic uterine leiomyomata were recruited in four centers and treated with 10 or 25 mg asoprisnil or placebo for 12 wk before surgery. At baseline and before hysterectomy, all patients underwent sonographic assessment to measure impedance to uterine artery blood flow, determined by resistance index and pulsatility index, as well as volumes of largest leiomyoma and uterus. In addition, patients recorded intensity and frequency of menstrual bleeding on a menstrual pictogram. Each asoprisnil treatment was compared with placebo.

RESULTS

The increased pulsatility index in both asoprisnil groups and the statistically significantly increased resistance index within the 25-mg asoprisnil group suggest a moderately decreased uterine artery blood flow. Analysis of menstrual pictogram scores showed a statistically significant larger decrease in frequency and intensity of bleeding for both asoprisnil groups compared with placebo. Bleeding was suppressed by asoprisnil 25mg in 91% of patients. Asoprisnil treatment was well tolerated when administered daily for a 12-wk period, and no serious adverse events occurred.

CONCLUSION

Asoprisnil moderately reduced uterine artery blood flow. This effect may contribute in part to the clinical effects of asoprisnil.

Investigational developments for the treatment of progesterone-dependent diseases

BACKGROUND

Clinical evidence has shown that conditions such as uterine fibroids, endometriosis and breast cancer are progesterone-dependent diseases. Therefore, progesterone receptor (PR) antagonists and selective PR modulators (SPRMs) are under development for the treatment of these conditions. However, the first PR antagonists that became available exhibit insufficient selectivity or tolerability for the chronic administration required to treat these conditions. Despite initial setbacks, development of second-generation PR antagonists with better selectivity continues forward.

OBJECTIVE

In this review we would like to summarise prospects for using PR antagonists for the treatment of uterine fibroids, endometriosis and breast cancer, and to give an overview of the development of new steroidal and non-steroidal PR antagonists.

METHOD

Available preclinical and clinical data and publications have been reviewed with the focus on scientific background and use in the three mentioned indications.

RESULTS/CONCLUSION

Preclinical and clinical evidence demonstrated that PR antagonists and SPRMs are effective for the treatment of progesterone-dependent diseases. Future development will demonstrate if they can become important drugs.

Estrogen regulates the localization and expression of calbindin-D9k in the pituitary gland of immature male rats via the ERalpha-pathway

Estrogen (E2; estradiol) plays a key role in the regulation of many pituitary hormones. It exerts its effects by binding to the intracellular estrogen receptor (ER), which then functions as a transcription factor. Although E2 has been shown to regulate calbindin-D(9k) (CaBP-9k) in the female reproductive system of rodents, the effects of E2 on the regulation of CaBP-9k in male rats remain to be elucidated. To investigate E2-induced regulation of the pituitary CaBP-9k gene, immature male rats were injected with E2 daily for 3 consecutive days with a dose of 40 microg/kg body weight (BW). The expression levels of CaBP-9k mRNA and protein were analyzed by RT-PCR and Western blot analysis, respectively, in the absence and presence of ICI 182,780 (ICI), an E2 antagonist. In addition, the tissue localization of CaBP-9k was determined by immunohistochemistry. CaBP-9k was localized in the cytoplasm of a specific cell type (acidophils) in the anterior lobe of the pituitary gland and highly expressed in the intermediate lobe. Exposure to E2 increased the number of cells that stained positive for CaBP-9k. To determine which ER subtype is involved in CaBP-9k regulation in the pituitary, the immature rats were treated with propyl pyrazole triol (PPT, an ERalpha-selective ligand) or diarylpropionitrile (DPN, an ERbeta-selective ligand) for 3 days. Pituitary CaBP-9k expression was mainly mediated by PPT in immature male rats, whereas no significant alteration of pituitary CaBP-9k gene expression was observed after DPN treatment. In addition, the estrogenicity of PPT in the induction of CaBP-9k expression was completely blocked by an estrogen antagonist, ICI, indicating that pituitary CaBP-9k expression is solely induced by ERalpha. Taken together, these results suggest that pituitary CaBP-9k is induced by E2 in male rats and its expression is predominantly regulated by ERalpha, but not ERbeta.

Molecular mechanism of regulation of the calcium-binding protein calbindin-D9k, and its physiological role(s) in mammals: a review of current research

Calbindin-D_9k (CaBP-9k) is a cytosolic calcium-binding protein that is expressed in a variety of tissues, such as uterus, placenta, intestine, kidney, pituitary gland and bone. At present, the precise role(s) of CaBP-9k remains to be clarified. CaBP-9k-null mice are normal, which indicates that other calcium-transporter genes can compensate for the lack CaBP-9k. Uterine CaBP-9k has been shown to be involved in the regulation of myometrial activity by intracellular calcium. In the uterus and placenta, CaBP-9k expression is regulated by the sex steroid hormones oestrogen (E2) and progesterone (P4). Intestinal CaBP-9k is involved in intestinal calcium absorption, and is regulated at the transcriptional and post-transcriptional levels by 1,25-dihydroxyvitamin D3, the hormonal form of vitamin D. Thus, evidence to date suggests that CaBP-9k may be regulated in a tissue-specific manner. In this review, we will summarize current data on the molecular mechanism of regulation of CaBP-9k in mammals, including recent research data generated in our laboratories.