A novel selective progesterone receptor modulator asoprisnil (J867) down-regulates the expression of EGF, IGF-I, TGFβ3 and their receptors in cultured uterine leiomyoma cells

Progesterone signaling in uterine fibroids: Molecular mechanisms and therapeutic opportunities

Progesterone (P4) is a vital female sex hormone involved in various physiological processes, including the maintenance of the endometrium, mammary gland development, and bone health. Beyond its reproductive roles, P4 is implicated in the pathogenesis of hormone-dependent conditions like uterine fibroids, the most common benign tumors in women, which can severely affect quality of life and fertility. Traditionally, estrogen was considered the primary driver of fibroid growth, but recent research highlights the significant role of P4 in fibroid growth. P4 interacts with progesterone receptors (PRs) and non-genomic membrane receptors (mPRs and PGRMCs) to activate signaling pathways that enhance tumor growth and survival. P4 promotes vascular changes that improve the blood supply to fibroids and modifies the extracellular matrix, a key component of fibroid structure. This understanding has led to the investigation of selective progesterone receptor modulators (SPRMs) as potential therapies for fibroids. Clinical trials have demonstrated the effectiveness of SPRMs like mifepristone, asoprisnil, and ulipristal acetate in reducing fibroid size and symptoms, though concerns about safety, particularly with long-term use, remain. Newer SPRMs, such as vilaprisan, show promise, but further research is necessary to assess the long-term safety and effectiveness. This review discusses the mechanisms by which progesterone contributes to fibroid growth and examines clinical effectiveness of SPRMs as potential treatments for uterine fibroids.

Progesterone signaling in uterine leiomyoma biology: Implications for potential targeted therapy

Uterine leiomyomas (ULs) are the most common benign smooth muscle cell steroid-dependent tumors that occur in women of reproductive age. Progesterone (P4) is a major hormone that promotes the ULs development and growth. P4 action in ULs is mediated mainly by its nuclear progesterone receptors (PGRs), although rapid non-genomic responses have also been observed. Data on the membrane progesterone receptors (mPRs) regulated signaling pathways in ULs in the available literature is still very limited. One of the essential characteristics of ULs is the excessive production of extracellular matrix (ECM). P4 has been shown to stimulate ECM production and collagen synthesis in ULs. Recent research demonstrated that, despite their benign nature, ULs may present with abnormal vasculature. P4 has been shown to regulate angiogenesis in ULs through the upregulation of vascular endothelial growth factor (VEGF) and by controlling the secretion of permeability factors. This review summarizes the key findings regarding the role of PGRs and mPRs in ULs, especially highlighting the potential ECM and angiogenesis modulation by P4. An increased understanding of this mechanistic role of nuclear and specifically mPRs in the biology of P4-modulated ECM and angiogenesis in the growth of ULs could turn out to be fundamental for developing effective targeted therapies for ULs.

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.

Selective Progesterone Receptor Modulators (SPRMs) and Androgen Receptor Modulators (SARMs) as Treatment for Benign Gynecologic Diseases

Common benign gynecologic conditions such as uterine fibroids and endometriosis are linked to chronic pelvic pain, abnormal and heavy uterine bleeding, and infertility. Effective medical management of these diseases is an unmet need. The steroid hormones progesterone (P4), estrogen (E2), and testosterone play a major role in reproductive physiology and uterine pathologies. Notably, selective progesterone receptor modulators have shown considerable promise as treatment options for some hormone-dependent conditions. More limited data are available regarding the safety and efficacy of selective androgen receptor modulators. In this report we review current evidence for selective progesterone receptor modulators and selective androgen receptor modulators as treatment options for benign gynecologic conditions.

Selective Progesterone Receptor Modulators-Mechanisms and Therapeutic Utility

Selective progesterone receptor modulators (SPRMs) are a new class of compounds developed to target the progesterone receptor (PR) with a mix of agonist and antagonist properties. These compounds have been introduced for the treatment of several gynecological conditions based on the critical role of progesterone in reproduction and reproductive tissues. In patients with uterine fibroids, mifepristone and ulipristal acetate have consistently demonstrated efficacy, and vilaprisan is currently under investigation, while studies of asoprisnil and telapristone were halted for safety concerns. Mifepristone demonstrated utility for the management of endometriosis, while data are limited regarding the efficacy of asoprisnil, ulipristal acetate, telapristone, and vilaprisan for this condition. Currently, none of the SPRMs have shown therapeutic success in treating endometrial cancer. Multiple SPRMs have been assessed for efficacy in treating PR-positive recurrent breast cancer, with in vivo studies suggesting a benefit of mifepristone, and multiple in vitro models suggesting the efficacy of ulipristal acetate and telapristone. Mifepristone, ulipristal acetate, vilaprisan, and asoprisnil effectively treated heavy menstrual bleeding (HBM) in patients with uterine fibroids, but limited data exist regarding the efficacy of SPRMs for HMB outside this context. A notable class effect of SPRMs are benign, PR modulator-associated endometrial changes (PAECs) due to the actions of the compounds on the endometrium. Both mifepristone and ulipristal acetate are effective for emergency contraception, and mifepristone was approved by the US Food and Drug Administration (FDA) in 2012 for the treatment of Cushing's syndrome due to its additional antiglucocorticoid effect. Based on current evidence, SPRMs show considerable promise for treatment of several gynecologic conditions.

The effect of ulipristal acetate on tumor necrosis factor α, insulin-like growth factor 1, and plasminogen activator inhibitor-1 serum levels in patients with symptomatic uterine fibroids

Introduction

Uterine fibroids (UFs) are benign tumors of the female reproductive system originating from the smooth muscle of the uterus. Currently, progesterone is known to play a key role in the differentiation of the myometrial tissue to form UFs and their abnormal growth. The mechanism of action of progesterone in UF tumorigenesis involves its effect on increasing the concentrations and dysregulation of selected growth factors.

Material and methods

A retrospective cohort study was performed to evaluate and compare tumor necrosis factor α (TNF-α), insulin-like growth factor 1 (IGF-1), plasminogen activator inhibitor-1 (PAI-1) serum concentrations in patients with UFs without prior hormonal treatment, patients with UFs treated with a 3-month standard ulipristal acetate (UPA - a type of selective progesterone receptor modulator) scheme (5 mg/day) and in control patients without UFs. A total of 120 patients were divided into 3 groups (controls, UFs with UPA treatment, UFs without UPA treatment).

Results

There were no significant differences in TNF-α serum concentrations between patients with UFs who underwent UPA treatment and patients who did not. Serum concentrations of IGF-1 and PAI-1 did not show significant intergroup differences.

Conclusions

No significant differences were found between TNF-α concentrations in the serum of patients with UFs treated with UPA, and patients without UPA treatment. In addition, our data analysis did not show significant differences in the concentrations of IGF-1 and PAI-1 between patients with UFs and the control group. Further studies on the dependence of specific symptoms on selected growth factors are mandatory.

Uterine fibroids: an update on current and emerging medical treatment options

Uterine fibroids are the most common gynecological disorder, classically requiring surgery when symptomatic. Although attempts at finding a nonsurgical cure date back to centuries, it is only around the middle of the last century that serious attempts at a medical treatment were carried out. Initially, both progestins and estrogen–progestin combinations have been utilized, although proof of their usefulness is lacking. A major step forward was achieved when peptide analogs of the GnRH were introduced, first those with superagonist properties and subsequently those acting as antagonists. Initially, the latter produced side effects preventing their routine utilization; eventually, this problem was overcome following the synthesis of cetrorelix. Because both types of analogs produce hypoestrogenism, their use is limited to a maximum of 6 months and, for this reason, today they are utilized as an adjuvant treatment before surgery with overall good results. Over the last decade, new, nonpeptidic, orally active GnRH-receptor blockers have also been synthesized. One of them, Elagolix, is in the early stages of testing in women with fibroids. Another fundamental development has been the utilization of the so-called selective progesterone receptor modulators, sometimes referred to as “antiprogestins”. The first such compound to be applied to the long-term treatment of fibroids was Mifepristone; today, this compound is mostly used outside of Western Countries, where the substance of choice is Ulipristal acetate. Large clinical trials have proven the effectiveness of Ulipristal in the long-term medical therapy of fibroids, although some caution must be exercised because of the rare occurrence of liver complications. All selective progesterone receptor modulators produce unique endometrial changes that are today considered benign, reversible, and without negative consequences. In conclusion, long-term medical treatment of fibroids seems possible today, especially in premenopausal women.

A Comprehensive Review of the Pharmacologic Management of Uterine Leiomyoma

Uterine leiomyomata are the most common benign tumors of the gynecologic tract impacting up to 80% of women by 50 years of age. It is well established that these tumors are the leading cause for hysterectomy with an estimated total financial burden greater than $30 billion per year in the United States. However, for the woman who desires future fertility or is a poor surgical candidate, definitive management with hysterectomy is not an optimal management plan. Typical gynecologic symptoms of leiomyoma include infertility, abnormal uterine bleeding (AUB)/heavy menstrual bleeding (HMB) and/or intermenstrual bleeding (IMB) with resulting iron-deficiency anemia, pelvic pressure and pain, urinary incontinence, and dysmenorrhea. The morbidity caused by these tumors is directly attributable to increases in tumor burden. Interestingly, leiomyoma cells within a tumor do not rapidly proliferate, but rather the increase in tumor size is secondary to production of an excessive, stable, and aberrant extracellular matrix (ECM) made of disorganized collagens and proteoglycans. As a result, medical management should induce leiomyoma cells toward dissolution of the extracellular matrix, as well as halting or inhibiting cellular proliferation. Herein, we review the current literature regarding the medical management of uterine leiomyoma.

Proteoglycans in Leiomyoma and Normal Myometrium: Abundance, Steroid Hormone Control, and Implications for Pathophysiology

Uterine leiomyoma are a common benign pelvic tumors composed of modified smooth muscle cells and a large amount of extracellular matrix (ECM). The proteoglycan composition of the leiomyoma ECM is thought to affect pathophysiology of the disease. To test this hypothesis, we examined the abundance (by immunoblotting) and expression (by quantitative real-time polymerase chain reaction) of the proteoglycans biglycan, decorin, and versican in leiomyoma and normal myometrium and determined whether expression is affected by steroid hormones and menstrual phase. Leiomyoma and normal myometrium were collected from women (n = 17) undergoing hysterectomy or myomectomy. In vitro studies were performed on immortalized leiomyoma (UtLM) and normal myometrial (hTERT-HM) cells with and without exposure to estradiol and progesterone. In leiomyoma tissue, abundance of decorin messenger RNA (mRNA) and protein were 2.6-fold and 1.4-fold lower, respectively, compared with normal myometrium. Abundance of versican mRNA was not different between matched samples, whereas versican protein was increased 1.8-fold in leiomyoma compared with myometrium. Decorin mRNA was 2.4-fold lower in secretory phase leiomyoma compared with proliferative phase tissue. In UtLM cells, progesterone decreased the abundance of decorin mRNA by 1.3-fold. Lower decorin expression in leiomyoma compared with myometrium may contribute to disease growth and progression. As decorin inhibits the activity of specific growth factors, its reduced level in the leiomyoma cell microenvironment may promote cell proliferation and ECM deposition. Our data suggest that decorin expression in leiomyoma is inhibited by progesterone, which may be a mechanism by which the ovarian steroids affect leiomyoma growth and disease progression.

Targeting oxidative stress to treat endometriosis

INTRODUCTION

Endometriosis affects 10% of women of reproductive age. It is defined as the presence of implanted active endometrial tissue outside the uterine cavity. The exact pathophysiology of endometriosis is still uncertain, although several optional etiological theories have been suggested. Being so common, a novel treatment for endometriosis is widely quested. Recent studies addressing the pathological characteristics of endometriosis have revealed a vicious cycle in which oxidative stress (OS) is generated, which in turn facilitates the implantation of the ectopic endometrium. At the same time, the generation of high amounts of reactive oxygen species further triggers a state of OS.

AREAS COVERED

The author examined the evidence associating OS and endometriosis. After establishing an association, a search for antioxidant agents that were investigated specifically on endometriosis patients are described including Vitamins C and E, melatonin, resveratrol, xanthohumol and epigallocatechin-3-gallate. A significant effect of all the reviewed antioxidants on endometriosis is reported.

EXPERT OPINION

Aiming for the reduction of OS as the treatment goal for endometriosis looks promising. However, since most of the studies are either in vitro or are animal based, further studies on human subjects are deemed necessary to elucidate the impact of OS reduction on patients with endometriosis.

Role of nuclear progesterone receptor isoforms in uterine pathophysiology

BACKGROUND

Progesterone is a key hormonal regulator of the female reproductive system. It plays a major role to prepare the uterus for implantation and in the establishment and maintenance of pregnancy. Actions of progesterone on the uterine tissues (endometrium, myometrium and cervix) are mediated by the combined effects of two progesterone receptor (PR) isoforms, designated PR-A and PR-B. Both receptors function primarily as ligand-activated transcription factors. Progesterone action on the uterine tissues is qualitatively and quantitatively determined by the relative levels and transcriptional activities of PR-A and PR-B. The transcriptional activity of the PR isoforms is affected by specific transcriptional coregulators and by PR post-translational modifications that affect gene promoter targeting. In this context, appropriate temporal and cell-specific expression and function of PR-A and PR-B are critical for normal uterine function.

METHODS

Relevant studies describing the role of PRs in uterine physiology and pathology (endometriosis, uterine leiomyoma, endometrial cancer, cervical cancer and recurrent pregnancy loss) were comprehensively searched using PubMed, Cochrane Library, Web of Science, and Google Scholar and critically reviewed.

RESULTS

Progesterone, acting through PR-A and PR-B, regulates the development and function of the endometrium and induces changes in cells essential for implantation and the establishment and maintenance of pregnancy. During pregnancy, progesterone via the PRs promotes myometrial relaxation and cervical closure. Withdrawal of PR-mediated progesterone signaling triggers menstruation and parturition. PR-mediated progesterone signaling is anti-mitogenic in endometrial epithelial cells, and as such, mitigates the tropic effects of estrogen on eutopic normal endometrium, and on ectopic implants in endometriosis. Similarly, ligand-activated PRs function as tumor suppressors in endometrial cancer cells through inhibition of key cellular signaling pathways required for growth. In contrast, progesterone via PR activation appears to increase leiomyoma growth. The exact role of PRs in cervical cancer is unclear. PRs regulate implantation and therefore aberrant PR function may be implicated in recurrent pregnancy loss (RPL). PRs likely regulate key immunogenic factors involved in RPL. However, the exact role of PRs in the pathophysiology of RPL and the use of progesterone for therapeutic benefit remains uncertain.

CONCLUSIONS

PRs are key mediators of progesterone action in uterine tissues and are essential for normal uterine function. Aberrant PR function (due to abnormal expression and/or function) is a major cause of uterine pathophysiology. Further investigation of the underlying mechanisms of PR isoform action in the uterus is required, as this knowledge will afford the opportunity to create progestin/PR-based therapeutics to treat various uterine pathologies.

Ovarian steroids, stem cells and uterine leiomyoma: therapeutic implications

BACKGROUND

Uterine leiomyoma is the most common benign tumor in women and is thought to arise from the clonal expansion of a single myometrial smooth muscle cell transformed by a cellular insult. Leiomyomas cause a variety of symptoms, including abnormal uterine bleeding, pelvic pain, bladder or bowel dysfunction, and recurrent pregnancy loss, and are the most common indication for hysterectomy in the USA. A slow rate of cell proliferation, combined with the production of copious amounts of extracellular matrix, accounts for tumor expansion. A common salient feature of leiomyomas is their responsiveness to steroid hormones, thus providing an opportunity for intervention.

METHODS

A comprehensive search of PUBMED was conducted to identify peer-reviewed literature published since 1980 pertinent to the roles of steroid hormones and somatic stem cells in leiomyoma, including literature on therapeutics that target steroid hormone action in leiomyoma. Reviewed articles were restricted to English language only. Studies in both animals and humans were reviewed for the manuscript.

RESULTS

Estrogen stimulates the growth of leiomyomas, which are exposed to this hormone not only through ovarian steroidogenesis, but also through local conversion of androgens by aromatase within the tumors themselves. The primary action of estrogen, together with its receptor estrogen receptor α (ERα), is likely mediated via induction of progesterone receptor (PR) expression, thereby allowing leiomyoma responsiveness to progesterone. Progesterone has been shown to stimulate the growth of leiomyoma through a set of key genes that regulate both apoptosis and proliferation. Given these findings, aromatase inhibitors and antiprogestins have been developed for the treatment of leiomyoma, but neither treatment results in complete regression of leiomyoma, and tumors recur after treatment is stopped. Recently, distinct cell populations were discovered in leiomyomas; a small population showed stem-progenitor cell properties, and was found to be essential for ovarian steroid-dependent growth of leiomyomas. Interestingly, these stem-progenitor cells were deficient in ERα and PR and instead relied on the strikingly higher levels of these receptors in surrounding differentiated cells to mediate estrogen and progesterone action via paracrine signaling.

CONCLUSIONS

It has been well established that estrogen and progesterone are involved in the proliferation and maintenance of uterine leiomyoma, and the majority of medical treatments currently available for leiomyoma work by inhibiting steroid hormone production or action. A pitfall of these therapeutics is that they decrease leiomyoma size, but do not completely eradicate them, and tumors tend to regrow once treatment is stopped. The recent discovery of stem cells and their paracrine interactions with more differentiated cell populations within leiomyoma has the potential to provide the missing link between developing therapeutics that temper leiomyoma growth and those that eradicate them.

Matrix production and remodeling as therapeutic targets for uterine leiomyoma

Uterine leiomyoma, commonly known as fibroids, is a benign neoplasm of smooth muscle in women. The incidence of clinically symptomatic fibroids in reproductive-age women is approximately 20 %, with nearly 80 % of black women suffering from this condition. Symptoms include severe pain and hemorrhage; fibroids are also a major cause of infertility or sub-fertility in women. Uterine leiomyoma consist of hyperplastic smooth muscle cells and an excess deposition of extracellular matrix, specifically collagen, fibronectin, and sulfated proteoglycans. Extracellular matrix components interact and signal through integrin-β1 on the surface of uterine leiomyoma smooth muscle cells, provide growth factor storage, and act as co-receptors for growth factor-receptor binding. ECM and growth factor signaling through integrin-β1 and growth factor receptors significantly increases cell proliferation and ECM deposition in uterine leiomyoma. Growth factors TGF-β, IGF, PDGF, FGF and EGF are all shown to promote uterine leiomyoma progression and signal through multiple pathways to increase the expression of genes encoding matrix or matrix-modifying proteins. Decreasing integrin expression, reducing growth factor action and inhibiting ECM action on uterine leiomyoma smooth muscle cells are important opportunities to treat uterine leiomyoma without use of the current surgical procedures. Both natural compounds and chemicals are shown to decrease fibrosis and uterine leiomyoma progression, but further analysis is needed to make inroads in treating this common women's health issue.

Receptors of hypothalamic-pituitary-ovarian-axis hormone in uterine myomas

In this study the expression of GnRH, FSH, LH, ER-α, ER-β, and PR receptors was examined in uterine myomas of women in reproductive and perimenopausal age. In cases of GnRH and tropic hormones a membranous and cytoplasmic immunohistochemical reaction was detected, in cases of ER-α and PR the reaction was located in cell nucleus, and in the case of ER-β it manifested also a cytoplasmic location. In some of the examined cases the expression was detected in endometrium, myocytes, and endothelium of blood vessels, in uterine glands and myoma cells. In myometrium the level of GnRH and LH receptors increases with age, whereas the level of progesterone and both estrogen receptors decreases. In myomas of women in reproductive age, independently of their size, expression of GnRH, FSH, and LH receptors was more pronounced than in myometrium. In women of perimenopausal age, independently of myoma size, expression of LH and estrogen α receptors was higher while expression of GnRH receptors was lower than in myometrium. FSH receptor expression was not observed. Expression of estrogen receptor β was not affected by age of the woman or size of myoma. Analysis of obtained results indicates on existing in small myomas local feedback axis between GnRH-LH-progesterone.

Expression profiling and significance of VEGF-A, VEGFR2, VEGFR3 and related proteins in endometrial carcinoma

BACKGROUND

Angiogenesis plays a key role in the progression of various tumors, including endometrial carcinomas. Several cytokines and their associated receptors are shown to be involved, particularly VEGF-A with VEGFR1, -2 and -3.

METHODS

The expressions of VEGF-A, VEGFR2 and VEGFR3 were studied in by immunohistochemistry in 76 endometrial carcinoma specimens. VEGFR2 and VEGFR3 receptor expression were also studied by qRT-PCR in 17 tumors in comparison to normal endometrium. The expression profiles were correlated with tumor type, grade, stage, lymphovascular invasion, disease free survival, and the expressions of other cytokine receptors (EGFR, CXCR1 and CXCR2).

RESULTS

Immunohistochemically, 63% of endometrial cancers expressed VEGF-A, 55% VEGFR2 and 26% VEGFR3. VEGFR3 was significantly correlated with tumor stage (p=0.02), with a trend towards poorer disease free survival (p=0.09). VEGF-A was significantly correlated with microvessel density (p<0.01). Using qRT-PCR, increased expression of VEGFR2 (17.2-fold) and VEGFR3 (21.9-fold) was seen in endometrial carcinomas compared with normal endometrium, with significant correlations among the expression levels of VEGFR2, VEGFR3, EGFR, CXCR1 and CXCR2.

CONCLUSION

Our study suggests that evaluation of VEGFR3 expression in tumors may provide prognostic data, and help identify patients who would best benefit from anti-angiogenic therapeutic agents. This is the first report showing correlations between the expressions levels of the different receptors.

Selective progesterone receptor modulators: an update

INTRODUCTION

Several selective progesterone receptor modulators (SPRMs) show promise in several areas of medicine and this work has been summarized by us in 2008.

AREAS COVERED

Since the publication of our reviews, several developments have taken place in the field of reproductive medicine. The first is emergency contraception (EC). Two SPRMs are clinically utilized today: mifepristone (MFP) and ulipristal acetate (UPA). MFP is available for EC in up to 120 h following unprotected intercourse. A dose of 10 mg is significantly more effective than levonorgestrel (LNG). In a metanalysis of the use of UPA versus LNG up to 72 h after unprotected intercourse, failure rates of 1.4 versus 2.2% were reported. The second is contraception. A daily dose of 2 mg MFP can block ovulation and several MFP regimens are being tested, including a vaginal ring releasing MFP. The third is the preoperative administration in women harboring leiomyomas, where clinical testing of several SPRM has shown that they can decrease uterine leiomyomas' size and substantially reduce uterine bleeding. SPRM can induce unusual, specific endometrial appearances. Many believe that these changes should not cause concern, but the issue remains controversial.

EXPERT OPINION

SPRMs are very effective in EC and for the preoperative treatment of uterine leiomyomas.

The potential of selective progesterone receptor modulators for the treatment of uterine fibroids

In addition to the estrogen receptor, the progesterone receptor plays an important role in the growth of uterine fibroids. Several selective progesterone receptor modulators (SPRMs) have been evaluated for medical treatment of uterine fibroids and, because of safety issues, some molecules were stopped during clinical development. However, in 2012, ulipristal acetate received the approval for a pre-surgical treatment of uterine fibroids. Clinical trials with ulipristal acetate for long-term medical treatment of uterine fibroids are ongoing. This review article describes the action of SPRMs at the progesterone receptor level and the mechanism of action on the fibroid tissue. A review of the published clinical trials is performed, including the current evidence of efficacy on uterine fibroid symptom management, size reduction and tolerability. The therapeutic potential of SPRMs for uterine fibroids is discussed.

The role of angiogenic factors in fibroid pathogenesis: potential implications for future therapy

BACKGROUND

It is well established that tumors are dependent on angiogenesis for their growth and survival. Although uterine fibroids are known to be benign tumors with reduced vascularization, recent work demonstrates that the vasculature of fibroids is grossly and microscopically abnormal. Accumulating evidence suggests that angiogenic growth factor dysregulation may be implicated in these vascular and other features of fibroid pathophysiology.

METHODS

Literature searches were performed in PubMed and Google Scholar for articles with content related to angiogenic growth factors and myometrium/leiomyoma. The findings are hereby reviewed and discussed.

RESULTS

Multiple growth factors involved in angiogenesis are differentially expressed in leiomyoma compared with myometrium. These include epidermal growth factor (EGF), heparin-binding-EGF, vascular endothelial growth factor, basic fibroblast growth factor, platelet-derived growth factor, transforming growth factor-β and adrenomedullin. An important paradox is that although leiomyoma tissues are hypoxic, leiomyoma feature down-regulation of key molecular regulators of the hypoxia response. Furthermore, the hypoxic milieu of leiomyoma may contribute to fibroid development and growth. Notably, common treatments for fibroids such as GnRH agonists and uterine artery embolization (UAE) are shown to work at least partly via anti-angiogenic mechanisms.

CONCLUSIONS

Angiogenic growth factors play an important role in mechanisms of fibroid pathophysiology, including abnormal vasculature and fibroid growth and survival. Moreover, the fibroid's abnormal vasculature together with its aberrant hypoxic and angiogenic response may make it especially vulnerable to disruption of its vascular supply, a feature which could be exploited for treatment. Further experimental studies are required in order to gain a better understanding of the growth factors that are involved in normal and pathological myometrial angiogenesis, and to assess the potential of anti-angiogenic treatment strategies for uterine fibroids.

Racial and ethnic differences in the pathogenesis and clinical manifestations of uterine leiomyoma

Uterine leiomyomas are the most common benign gynecologic condition. The prevalence is three times more common among women of African ethnicity. Disparity in this disease is evidenced by earlier age of onset, greater severity of symptoms, and different response to treatment. Although the pathogenesis of disease development is not completely known, growing evidence focuses on investigating the molecular mechanisms in disease development and the influence of ethnicity. Variation in the expression levels or function of estrogen and progesterone receptors, polymorphism of genes involved in estrogen synthesis and/or metabolism (COMT, CYP17), retinoic acid nuclear receptors (retinoid acid receptor-α, retinoid X receptor-α), and aberrant expression of micro-RNAs (miRNAs) are some of the molecular mechanisms that may be involved. Nutritional factors, such as vitamin D deficiency, might also contribute to the higher incidence in dark skinned populations who are also commonly suffer from hypovitaminosis D. Culture and environmental difference might have a role in disease development. Further analysis and better understanding of these mechanisms will provide insight into the molecular basis of racial disparities in leiomyoma formation and will help to develop new innovations in leiomyoma treatment.

Effect of lichong decoction on expression of IGF-I and proliferating cell nuclear antigen mRNA in rat model of uterine leiomyoma

OBJECTIVE

To study the effect of Lichong Decoction (Lichong Decoction for strengthening anti-pathogenic Qi and eliminating blood stasis) on the expression of insulin-like growth factor-I (IGF-I) and proliferating cell nuclear antigen (PCNA) mRNA in a rat model of uterine leiomyoma.

METHODS

Fifty female Wistar rats were randomized into a normal control group, model group, Lichong Decoction group, Guizhifuling Capsule (Capsule containing Cassia Twig and Poria) group, and Mifepristone group. The uterine leiomyoma model was established by peritoneal injections of exogenous estrogen and progesterone hormone. The ultrastructural changes in cells of rat uterine tissues were observed with transmission electron microscopy, and the expression of IGF-I and PCNA mRNA was detected by real-time fluorescent quantitative PCR.

RESULTS

Following treatment, cells in the Lichong Decoction group appeared to be arranged normally, the cellular morphology were almost in a normal state, hyperplasia and hypertrophy of the chondriosome was reduced, collagen fibers were arranged in a regular manner, without obvious hyperplasia, and the expression of IGF-I and PCNA mRNA was significantly decreased compared with the model group (P < 0.01).

CONCLUSIONS

The effect of Lichong Decoction on uterine leiomyoma is related to its function in reducing the expression of IGF-I and PCNA mRNA.

Uterine leiomyoma: available medical treatments and new possible therapeutic options

CONTEXT

Uterine leiomyomas (fibroids or myomas) are benign tumors of the uterus and are clinically apparent in up to 25% of reproductive-age women. Heavy or abnormal uterine bleeding, pelvic pain or pressure, infertility, and recurrent pregnancy loss are generally associated with leiomyoma. Although surgical and radiological therapies are frequently used for the management of this tumor, medical therapies are considered the first-line treatment of leiomyoma.

EVIDENCE ACQUISITION AND SYNTHESIS

A review was conducted of electronic and print data comprising both original and review articles on pathophysiology and medical treatments of uterine leiomyoma retrieved from the PubMed or Google Scholar database up to June 2012. These resources were integrated with the authors' knowledge of the field.

CONCLUSION

To date, several pathogenetic factors such as genetic factors, epigenetic factors, estrogens, progesterone, growth factors, cytokines, chemokines, and extracellular matrix components have been implicated in leiomyoma development and growth. On the basis of current hypotheses, several medical therapies have been investigated. GnRH agonist has been approved by US Food and Drug Administration for reducing fibroid volume and related symptoms. In addition, the FDA also approved an intrauterine device, levonorgestrel-releasing intrauterine system (Mirena), for additional use to treat heavy menstrual bleeding in intrauterine device users only. Currently, mifepristone, asoprisnil, ulipristal acetate, and epigallocatechin gallate have been shown to be effective for fibroid regression and symptomatic improvement which are all in clinical trial. In addition, some synthetic and natural compounds as well as growth factor inhibitors are now under laboratory investigation, and they could serve as future therapeutic options.

Fibroid-associated heavy menstrual bleeding: correlation between clinical features, Doppler ultrasound assessment of vasculature, and tissue gene expression profiles

Despite the prevalence of uterine fibroids (Fs), few studies have investigated the links between clinical features and the cellular or molecular mechanisms that drive F growth and development. Such knowledge will ultimately help to differentiate symptomatic from asymptomatic Fs and could result in the development of more effective and individualized treatments. The aim of this study was to investigate the relationship between ultrasound appearance, blood flow, and angiogenic gene expression in F, perifibroid (PM), and distant myometrial (DM) tissues. We hypothesized that angiogenic gene expression would be increased in tissues and participants that showed increased blood flow by Doppler ultrasound. The study was performed using Doppler ultrasound to measure blood flow prior to hysterectomy, with subsequent tissue samples from the F, PM, and DM being investigated for angiogenic gene expression. Overall, PM blood flow (measured as peak systolic velocity [PSV]) was higher than F blood flow, although significant heterogeneity was seen in vascularity and blood flow between different Fs and their surrounding myometrium. We did not find any correlation between PSV and any other clinical or molecular parameter in this study. We identified 19 angiogenesis pathway-related genes with significant differences in expression between F and DM, and 2 genes, matrix metalloproteinase 9 (MMP9) and Neuropilin 2 (NRP2), that were significantly different between F and PM. These results are consistent with subtle differences between PM and DM. Understanding the differences between symptomatic versus asymptomatic Fs may eventually lead to more effective treatments that directly target the source of heavy menstrual bleeding.

The role of progesterone signaling in the pathogenesis of uterine leiomyoma

Uterine leiomyomas are benign tumors that originate from the myometrium. Evidence points to ovarian steroid hormones, in particular, progesterone as major promoters of leiomyoma development and growth. While progesterone action in leiomyomas involves the classical nuclear receptor effects on gene regulation, there is growing evidence that signaling pathways are directly activated by the progesterone receptor (PR) and that PR can interact with growth factor signaling systems to promote proliferation and survival of leiomyomas. Studies investigating the genomic and non-genomic actions of PR and its role in leiomyoma growth are summarized here. Studies testing various selective progesterone receptor modulators for the treatment of leiomyomas are also highlighted. An increased understanding of the mechanisms associated with progesterone-driven growth of leiomyomas is critical in order to develop more efficient and targeted therapies for this prevalent disease.

X-ray structures of progesterone receptor ligand binding domain in its agonist state reveal differing mechanisms for mixed profiles of 11β-substituted steroids

We present here the x-ray structures of the progesterone receptor (PR) in complex with two mixed profile PR modulators whose functional activity results from two differing molecular mechanisms. The structure of Asoprisnil bound to the agonist state of PR demonstrates the contribution of the ligand to increasing stability of the agonist conformation of helix-12 via a specific hydrogen-bond network including Glu(723). This interaction is absent when the full antagonist, RU486, binds to PR. Combined with a previously reported structure of Asoprisnil bound to the antagonist state of the receptor, this structure extends our understanding of the complex molecular interactions underlying the mixed agonist/antagonist profile of the compound. In addition, we present the structure of PR in its agonist conformation bound to the mixed profile compound Org3H whose reduced antagonistic activity and increased agonistic activity compared with reference antagonists is due to an induced fit around Trp(755), resulting in a decreased steric clash with Met(909) but inducing a new internal clash with Val(912) in helix-12. This structure also explains the previously published observation that 16α attachments to RU486 analogs induce mixed profiles by altering the binding of 11β substituents. Together these structures further our understanding of the steric and electrostatic factors that contribute to the function of steroid receptor modulators, providing valuable insight for future compound design.

Ulipristal acetate versus leuprolide acetate for uterine fibroids

BACKGROUND

The efficacy and side-effect profile of ulipristal acetate as compared with those of leuprolide acetate for the treatment of symptomatic uterine fibroids before surgery are unclear.

METHODS

In this double-blind noninferiority trial, we randomly assigned 307 patients with symptomatic fibroids and excessive uterine bleeding to receive 3 months of daily therapy with oral ulipristal acetate (at a dose of either 5 mg or 10 mg) or once-monthly intramuscular injections of leuprolide acetate (at a dose of 3.75 mg). The primary outcome was the proportion of patients with controlled bleeding at week 13, with a prespecified noninferiority margin of -20%.

RESULTS

Uterine bleeding was controlled in 90% of patients receiving 5 mg of ulipristal acetate, in 98% of those receiving 10 mg of ulipristal acetate, and in 89% of those receiving leuprolide acetate, for differences (as compared with leuprolide acetate) of 1.2 percentage points (95% confidence interval [CI], -9.3 to 11.8) for 5 mg of ulipristal acetate and 8.8 percentage points (95% CI, 0.4 to 18.3) for 10 mg of ulipristal acetate. Median times to amenorrhea were 7 days for patients receiving 5 mg of ulipristal acetate, 5 days for those receiving 10 mg of ulipristal acetate, and 21 days for those receiving leuprolide acetate. Moderate-to-severe hot flashes were reported for 11% of patients receiving 5 mg of ulipristal acetate, for 10% of those receiving 10 mg of ulipristal acetate, and for 40% of those receiving leuprolide acetate (P<0.001 for each dose of ulipristal acetate vs. leuprolide acetate).

CONCLUSIONS

Both the 5-mg and 10-mg daily doses of ulipristal acetate were noninferior to once-monthly leuprolide acetate in controlling uterine bleeding and were significantly less likely to cause hot flashes. (Funded by PregLem; ClinicalTrials.gov number, NCT00740831.).

Growth factors and myometrium: biological effects in uterine fibroid and possible clinical implications

BACKGROUND

Growth factors are proteins secreted by a number of cell types that are capable of modulating cellular growth, proliferation and cellular differentiation. It is well accepted that uterine cellular events such as proliferation and differentiation are regulated by sex steroids and their actions in target tissues are mediated by local production of growth factors acting through paracrine and/or autocrine mechanisms. Myometrial mass is ultimately modified in pregnancy as well as in tumour conditions such as leiomyoma and leiomyosarcoma. Leiomyomas, also known as fibroids, are benign tumours of the uterus, considered to be one of the most frequent causes of infertility in reproductive years in women.

METHODS

For this review, we searched the database MEDLINE and Google Scholar for articles with content related to growth factors acting on myometrium; the findings are hereby reviewed and discussed.

RESULTS

Different growth factors such as epidermal growth factor (EGF), transforming growth factor-α (TGF-α), heparin-binding EGF (HB-EGF), acidic fibroblast growth factor (aFGF), basic fibroblast growth factor (bFGF), vascular endothelial growth factor (VEGF), insulin-like growth factor (IGF), platelet-derived growth factor (PDGF) and TGF-β perform actions in myometrium and in leiomyomas. In addition to these growth factors, activin and myostatin have been recently identified in myometrium and leiomyoma.

CONCLUSIONS

Growth factors play an important role in the mechanisms involved in myometrial patho-physiology.

Lessons learned from the preclinical drug discovery of asoprisnil and ulipristal for non-surgical treatment of uterine leiomyomas

INTRODUCTION

Uterine leiomyoma is the most common benign tumor in women during the reproductive years. Menorrhagia is the common symptom and accounts for the most frequent indication for hysterectomy. Thus, development of a novel drug for non-surgical treatment of uterine leiomyoma is needed for the betterment of women's health.

AREA COVERED

This review introduces a translational research initiated by use of the levonorgestrel-releasing intrauterine system (LNG-IUS) for contraceptive purposes. During follow-up, a patient informed that heavy menstrual bleeding caused by uterine myoma was strikingly reduced after the insertion of device. The patient's unexpected comment led the authors to perform clinical trials of LNG-IUS for the management of menorrhagia in women with uterine myomas and striking reduction in menorrhagia was obtained by the use of LNG-IUS. MRI examination, however, revealed that the volume of myomas decreased in some, but increased in the other instances. This unexpected finding with MRI directed the authors to characterize the effects of progesterone (P4) and progesterone receptor modulators (PRMs) on uterineleiomyoma cell growth in vitro.

EXPERT OPINION

In consistence with the in vitro data obtained, randomized controlled clinical trials of PRMs in patients with uterine leiomyomas at several institutions have demonstrated that oral administration of PRMs (asoprisnil and ulipristal) for 3 months reduced leiomyoma volume, resulting in a significant improvement of the associated symptoms. However, a novel pattern of PRM-associated endometrial changes was recognized in the endometrial pathology, demonstrating unusual epithelial types not seen in the normal menstrual cycle of a premenstrual woman. Thus, follow-up studies to determine whether the novel endometrial changes remain, disappear or progress to something else are needed for the possible long-term use of PRMs for the treatment of uterine leiomyoma.

Translational research with progesterone receptor modulator motivated by the use of levonorgestrel-releasing intrauterine system

The use of levonorgestrel-releasing intrauterine system (LNG-IUS) is effective for management of menorrhagic women with uterine myomas because of reduction in menorrhagia. However, the size of myomas during use of LNG-IUS increased in some but decreased in other instances. This prompted us to characterize the effects of progesterone (P4) on cultured leiomyoma cell growth. Treatment with P4 resulted in increase in epidermal growth factor (EGF) expression in cultured leiomyoma cells, whereas treatment with E2 augmented EGF-R expression in those cells. This indicates that P4 and E2 act in combination to stimulate myoma growth through induction of EGF/EGF-R expression. Bcl-2 expression in leiomyoma cells was up-regulated by P4. Furthermore, P4 augmented proliferating cell nuclear antigen expression in cultured leiomyoma cells but not in cultured normal myometrial cells. This fact let us to examine the effects of progesterone receptor modulator (PRM) on leiomyoma cell proliferation and apoptosis in comparison with normal myometrial cells. Our studies revealed that CDB-2914 inhibits the proliferation, stimulates apoptosis of cultured leiomyoma cells, and inhibits the expression of angiogenic factors (vascular endothelial growth factor and adrenomedullin) and their receptors in cultured leiomyoma cells, without affecting those in cultured normal myometrial cells. We then evaluated the effects of CDB-2914 on extracellular matrix (ECM) components in cultured leiomyoma cells. CDB-2914 increased ECM metalloproteinase inducer, matrix metalloproteinase (MMP)-1, MMP-8 contents and decreased tissue inhibitors of MMP (TIMP)-1, TIMP-2 contents as well as type I and type III collagen contents in cultured leiomyoma cells, without comparable effects on cultured normal myometrial cells. These findings demonstrate that PRM not only inhibits the proliferation and stimulates apoptosis of cultured leiomyoma cells but also suppresses collagen synthesis in a cell-type specific manner. This is meaningful for understanding the molecular mechanism of the usefulness of PRM in the treatment of uterine fibroids.

Receptor tyrosine kinases and their hormonal regulation in uterine leiomyoma

Uterine leiomyomas (fibroids, myomas) are benign tumors that develop from smooth muscle cells. Although the most common gynecologic tumor in premenopausal women, there is still little known of the etiology, the genetics and basic/molecular biology, or the influence of the environment on the development and growth of these tumors. The fact that fibroids occur during the reproductive years and regress after menopause indicates a growth dependent on ovarian hormones. Studies have supported a role of estrogen and progesterone in leiomyoma growth possibly through regulating growth factors and their signaling pathways. Activation of steroid hormone receptors can have a myriad of effects and include upregulation of growth factors and receptor tyrosine kinases (RTKs), which through downstream effector proteins such as mitogen-activated protein kinase p44/42, can mediate transcription, translation, and cell proliferation. Due to their hormonal dependency, fibroids may also be targeted by environmental chemicals whose biological effects are mediated through the estrogen and/or progesterone receptors. This review focuses on the role of growth factors and their receptors (RTKs) in uterine leiomyoma growth and their regulation by ovarian hormones. It also presents data on specific signaling pathways activated in uterine leiomyomas and the "cross talk" between the estrogen receptor alpha and RTK signaling pathways.

Progesterone receptor action in leiomyoma and endometrial cancer

Progesterone is a key hormone in the regulation of uterine function. In the normal physiological context, progesterone is primarily involved in remodeling of the endometrium and maintaining a quiescent myometrium. When pathologies of the uterus develop, specifically, endometrial cancer and uterine leiomyoma, response to progesterone is usually altered. Progesterone acts through mainly two isoforms of the progesterone receptor (PR), PRA and PRB which have been reported to exhibit different transcriptional activities. Studies examining the expression and function of the PRs in the normal endometrium and myometrium as well as in endometrial cancer and uterine leiomyoma are summarized here. The clinical use of progestins and the transcriptional activity of the PR on genes specific to endometrial cancer and leiomyoma are described. An increased understanding of the differential expression of PRs and response to progesterone in these two diseases is critical in order to develop more efficient and targeted therapies.

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.

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

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

Differential expression of receptor tyrosine kinases (RTKs) and IGF-I pathway activation in human uterine leiomyomas

Uterine leiomyomas (fibroids) are benign tumors that are prevalent in women of reproductive age. Research suggests that activated receptor tyrosine kinases (RTKs) play an important role in the enhanced proliferation observed in fibroids. In this study, a phospho-RTK array technique was used to detect RTK activity in leiomyomas compared with myometrial tissue. We found that fifteen out of seventeen RTKs evaluated in this study were highly expressed (P < 0.02-0.03) in the leiomyomas, and included the IGF-I/IGF-IR, EGF/EGFR, FGF/FGF-R, HGF/HGF-R, and PDGF/PDGF-R gene families. Due to the higher protein levels of IGF-IR observed in leiomyomas by us in earlier studies, we decided to focus on the activation of the IGF-IR, its downstream effectors, and MAPKp44/42 to confirm our earlier findings; and validate the significance of the increased IGF-IR phosphorylation observed by RTK array analysis in this study. We used immunolocalization, western blot, or immunoprecipitation studies and confirmed that leiomyomas overexpressed IGF-IRbeta and phosphorylated IGF-IRbeta. Additionally, we showed that the downstream effectors, Shc, Grb2, and MAPKp44/42 (P < 0.02-0.001) were also overexpressed and involved in IGF-IR signaling in these tumors, while IRS-I, PI3K, and AKT were not. In vitro studies showed that IGF-I (100 ng/mL) increased the proliferation of uterine leiomyoma cells (UtLM) (P < 0.0001), and that phosphorylated IGF-IRbeta, Shc, and MAPKp44/42 were also overexpressed in IGF-I-treated UtLM cells (P < 0.05), similar to the tissue findings. A neutralizing antibody against the IGF-IRbeta blocked these effects. These data indicate that overexpression of RTKs and, in particular, activation of the IGF-IR signaling pathway through Shc/Grb2/MAPK are important in mediating uterine leiomyoma growth. These data may provide new anti-tumor targets for noninvasive treatment of fibroids.

Selective progesterone receptor modulator asoprisnil down-regulates collagen synthesis in cultured human uterine leiomyoma cells through up-regulating extracellular matrix metalloproteinase inducer

BACKGROUND

A recent clinical trial demonstrated that selective progesterone receptor modulator asoprisnil is effective in reducing uterine leiomyoma volume. We investigated the effects of asoprisnil in vitro on the expression of the extracellular matrix (ECM)-remodeling enzymes and collagens in cultured leiomyoma and matching normal myometrial cells.

METHODS

The expression of extracellular matrix metalloproteinase inducer (EMMPRIN), matrix metalloproteinases (MMPs), tissue inhibitors of MMP (TIMPs) and collagens were assessed by western blot analysis.

RESULTS

Untreated cultured leiomyoma cells had significantly lower EMMPRIN (P < 0.05), MMP-1 (P < 0.05) and membrane type 1-MMP (MT1-MMP) (P < 0.01) protein contents, but significantly higher TIMP-1 (P < 0.05), TIMP-2 (P < 0.01), type I (P < 0.05) and type III (P < 0.01) collagen protein contents compared with untreated cultured myometrial cells. Treatment with asoprisnil at concentrations > or =10(-7) M for 48 h significantly (P < 0.05) increased EMMPRIN, MMP-1 and MT1-MMP protein contents, and decreased TIMP-1 (P < 0.05), TIMP-2 (P < 0.01), type I (P < 0.01) and type III (P < 0.05 at 10(-7) M; P < 0.01 at 10(-6) M) collagen protein contents in cultured leiomyoma cells compared with control cultures. However, asoprisnil treatment did not affect the protein contents of ECM-remodeling enzymes and collagens in cultured myometrial cells.

CONCLUSIONS

These results suggest that asoprisnil may reduce collagen deposit in the ECM of cultured leiomyoma cells through decreasing collagen synthesis and enhancing the expression of EMMPRIN, MMPs and TIMPs without comparable effects on cultured myometrial cells.

Comparative effects of SPRM asoprisnil (J867) on proliferation, apoptosis, and the expression of growth factors in cultured uterine leiomyoma cells and normal myometrial cells

Progesterone plays a pivotal role in controlling uterine leiomyoma growth. The authors review studies they conducted to evaluate the comparative effects of asoprisnil on proliferation, apoptosis, and growth factor expression in cultured leiomyoma and normal myometrial cells. Treatment with asoprisnil decreased the proliferating cell nuclear antigen-positive rate and the number of viable cells and increased the terminal deoxynucleotidyl transferase-mediated 2'-deoxyuridine 5'-triphosphate nick end labeling- positive rate in cultured leiomyoma cells in a dose-dependent manner ( P < .05). Similarly, asoprisnil decreased Bcl-2 expression and increased cleaved caspase-3 and cleaved poly(adenosine 5'-diphosphate-ribose) polymerase in leiomyoma cells but not in normal myometrial cells. Similarly, asoprisnil decreased epidermal growth factor (EGF), insulin-like growth factor-I (IGF-I), and transforming growth factor (TGF) beta mRNA and protein expression, as well as EGF receptor, IGF-IR alpha, and TGF RII protein expression in leiomyoma cells but not in cultured normal myometrial cells. These results suggest that asoprisnil selectively inhibits proliferation by downregulating the growth factors and their receptor expression and induces apoptosis in leiomyoma cells without affecting proliferation and apoptosis in normal myometrial cells.

Selective progesterone receptor modulator asoprisnil induces endoplasmic reticulum stress in cultured human uterine leiomyoma cells

A recent clinical trial (Chwalisz K, Larsen L, Mattia-Goldberg C, Edmonds A, Elger W, Winkel CA. Fertil Steril 87: 1399-1412, 2007) has demonstrated that the selective progesterone receptor modulator asoprisnil efficiently causes the shrinkage of uterine leiomyoma. The present study was conducted to examine whether asoprisnil elicits endoplasmic reticulum (ER) stress-induced apoptosis in cultured human uterine leiomyoma cells. After subculture in phenol red-free DMEM supplemented with 10% FBS for 120 h, cultured cells were stepped down to serum-free conditions with or without graded concentrations of asoprisnil. ER stress-associated and apoptosis-related proteins were assessed by reverse transcription-PCR analysis or Western blot analysis. RNA interference of growth-arrest- and DNA-damage-inducible gene 153 (GADD153) was performed using small interfering RNA. Terminal deoxynucleotidyl transferase-mediated 2'-deoxyuridine 5'-triphosphate nick end labeling (TUNEL)-positive rates were assessed by TUNEL assay. Compared with untreated control cultures, treatment with 10(-7) M asoprisnil significantly (P < 0.05) increased the protein contents of ubiquitin at 2 h and phospho-double-stranded RNA-activated protein kinase-like ER kinase, phospho-eukaryotic initiation factor 2alpha, activating transcription factor 4, and glucose-regulated protein 78 kDa at 4 h, followed by the significant (P < 0.05) increase in GADD153 protein content at 6 h and cleaved poly(adenosine 5'-diphosphate ribose)polymerase (PARP) at 8 h. RNA interference of GADD153 suppressed protein contents of asoprisnil-induced cleaved PARP, Bax, Bak, GADD34, and tribbles-related protein 3 (TRB3) and TUNEL-positive rate but attenuated asoprisnil-induced reduction in Bcl-2 protein content in cultured leiomyoma cells. These results suggest that asoprisnil elicits ER stress-induced apoptosis in cultured leiomyoma cells and that GADD153 plays a role in asoprisnil-induced apoptosis by modulating the Bcl-2 family of proteins, GADD34, and TRB3.

Adenovirus-mediated delivery of a dominant-negative estrogen receptor gene in uterine leiomyoma cells abrogates estrogen- and progesterone-regulated gene expression

CONTEXT

Human uterine leiomyomas are very common smooth muscle cell tumors that occur in reproductive-age women and are the leading reason for performing hysterectomies. The present study was conducted to explore the potential mechanism behind the effects exerted by dominant-negative estrogen receptors (DNERs) delivered by adenovirus to leiomyoma cells to ascertain the utility of DNERs as a novel strategy for treatment of uterine fibroids.

OBJECTIVE AND METHODS

We investigated the ability of DNER to affect estrogen response element (ERE) activity induced by wild-type estrogen receptor (ER) by using the adenovirus ERE luciferase (Ad-ERE-luc) system in ELT3 cells and the effect of graded doses of DNER (10, 50, and 100 plaque-forming units/cell) on the expression of some selected genes controlling cultured human leiomyoma cell proliferation (cyclin D1, Cox2, PCNA, VEGF, and EGF), apoptosis (Bcl2 and Bax), estrogen metabolism (COMT), and extracellular matrix formation (MMP(1)) as well as progesterone receptors (A and B) were assessed using Western blot analysis. These genes are all regulated by estrogen and/or progesterone.

RESULTS

DNER has the ability to suppress the ERE luc activity induced by wild-type ER (P < 0.01) and significantly (P < 0.05) reverse the expression of all estrogen- and progesterone-regulated genes in this study.

CONCLUSIONS

These results suggest that interruption of the estrogen signaling pathway using DNER results in modulation of both estrogen- and progesterone-regulated genes that control leiomyoma cell apoptosis, proliferation, extracellular matrix formation, progesterone receptors, and estrogen metabolism, which might account for the DNER mechanism of action.

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.

A novel selective progesterone receptor modulator asoprisnil activates tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-mediated signaling pathway in cultured human uterine leiomyoma cells in the absence of comparable effects on myometrial cells

CONTEXT

We previously demonstrated that asoprisnil, a selective progesterone receptor modulator, induces apoptosis of cultured uterine leiomyoma cells. This study was conducted to evaluate whether asoprisnil activates TNF-related apoptosis-inducing ligand (TRAIL)-mediated apoptotic pathway in cultured uterine leiomyoma and matching myometrial cells.

OBJECTIVE AND METHODS

After subculture in phenol red-free DMEM supplemented with 10% fetal bovine serum for 120 h, cultured cells were stepped down to serum-free conditions for 24 h in the absence or presence of graded concentrations of asoprisnil. The levels of TRAIL signaling molecules and cellular inhibitors of apoptosis protein were assessed by Western blot analysis.

RESULTS

TRAIL contents in untreated cultured leiomyoma cells were significantly (P < 0.01) lower compared with those in untreated cultured myometrial cells. There was no difference in death receptor (DR)4 and DR5 contents between the two types of cells. Asoprisnil treatment significantly (P < 0.05) increased TRAIL, DR4, and DR5 contents in cultured leiomyoma cells in a dose-dependent manner with a cleavage of caspase-8, -7, and -3, and decreased X-linked chromosome-linked inhibitor of apoptosis protein contents. In cultured myometrial cells, however, asoprisnil treatment did not affect either TRAIL signaling molecule or cellular inhibitors of apoptosis protein contents. The concomitant treatment with 100 ng/ml P4 significantly (P < 0.05) reversed asoprisnil-induced increase in DR4 and cleaved poly(adenosine 5'-diphosphate-ribose) polymerase contents in cultured leiomyoma cells.

CONCLUSIONS

These results suggest that asoprisnil induces apoptosis of cultured leiomyoma cells by activating TRAIL-mediated apoptotic pathway and down-regulating X-linked chromosome-linked inhibitor of apoptosis protein levels in the absence of comparable effects on myometrial cells.

New Treatments for Uterine Fibroids

Since the introduction of uterine artery embolization as a minimally invasive treatment option for uterine fibroids, there has been a great deal of effort made toward developing other options for these patients. These options approach the problem differently, either with direct targeting of individual fibroids, organ-wide targeting of multiple fibroids, and systemic therapy to address the problem of fibroids using a hormonal approach. This review will focus on the different techniques and different philosophies that have been applied to the treatment of fibroids during the past decade.

Role of nonhuman primate models in the discovery and clinical development of selective progesterone receptor modulators (SPRMs)

Selective progesterone receptor modulators (SPRMs) represent a new class of progesterone receptor ligands that exert clinically relevant tissue-selective progesterone agonist, antagonist, partial, or mixed agonist/antagonist effects on various progesterone target tissues in an in vivo situation depending on the biological action studied. The SPRM asoprisnil is being studied in women with symptomatic uterine leiomyomata and endometriosis. Asoprisnil shows a high degree of uterine selectivity as compared to effects on ovulation or ovarian hormone secretion in humans. It induces amenorrhea and decreases leiomyoma volume in a dose-dependent manner in the presence of follicular phase estrogen concentrations. It also has endometrial antiproliferative effects. In pregnant animals, the myometrial, i.e. labor-inducing, effects of asoprisnil are blunted or absent. Studies in non-human primates played a key role during the preclinical development of selective progesterone receptor modulators. These studies provided the first evidence of uterus-selective effects of asoprisnil and structurally related compounds, and the rationale for clinical development of asoprisnil.