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 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.

Progesterone Signaling and Uterine Fibroid Pathogenesis; Molecular Mechanisms and Potential Therapeutics

Uterine fibroids (UFs) are the most important benign neoplastic threat to women's health worldwide, with a prevalence of up to 80% in premenopausal women, and can cause heavy menstrual bleeding, pain, and infertility. Progesterone signaling plays a crucial role in the development and growth of UFs. Progesterone promotes the proliferation of UF cells by activating several signaling pathways genetically and epigenetically. In this review article, we reviewed the literature covering progesterone signaling in UF pathogenesis and further discussed the therapeutic potential of compounds that modulate progesterone signaling against UFs, including selective progesterone receptor modulator (SPRM) drugs and natural compounds. Further studies are needed to confirm the safety of SPRMs as well as their exact molecular mechanisms. The consumption of natural compounds as a potential anti-UFs treatment seems promising, since these compounds can be used on a long-term basis-especially for women pursuing concurrent pregnancy, unlike SPRMs. However, further clinical trials are needed to confirm their effectiveness.

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.

Cross-talk between miR-29c and transforming growth factor-β3 is mediated by an epigenetic mechanism in leiomyoma

OBJECTIVE

To determine the expression of miR-29c and its target gene transforming growth factor-β3 (TGF-β3) in leiomyoma and the mechanisms of their reciprocal regulation.

DESIGN

Experimental study.

SETTING

Academic research laboratory.

PATIENT(S)

Women undergoing hysterectomy for leiomyoma.

INTERVENTION(S)

Overexpression and underexpression of miR-29c; blockade of DNA methyltransferase 1 (DNMT1).

MAIN OUTCOME MEASURE(S)

The miR-29c and its target gene TGF-β3 in leiomyoma and the effects of TGF-β3 and blockade of DNMT1 on miR-29c expression.

RESULT(S)

Leiomyoma expressed significantly lower levels of miR-29c, but higher expression of TGF-β3 compared with matched myometrium. The expression of TGF-β3 and miR-29c were independent of race/ethnicity. Using 3' untranslated region luciferase reporter assay we confirmed that TGF-β3 is a direct target of miR-29c in leiomyoma smooth muscle cells (LSMCs). Gain-of-function of miR-29c in LSMCs inhibited the expression of TGF-β3 at protein and messenger RNA levels, whereas loss-of-function of miR-29c had the opposite effect. Treatment of LSMCs with TGF-β3 inhibited the expression of miR-29c, whereas it stimulated DNMT1 expression. Knockdown of DNMT1 through transfection with small interfering RNA significantly decreased the expression of TGF-β3, and induced miR-29c expression. Knockdown of DNMT1 also attenuated the inhibitory effect of TGF-β3 on miR-29c expression. Furthermore, we demonstrated that TGF-β3 increased the methylation level of miR-29c promoter in LSMCs.

CONCLUSION(S)

There is an inverse relationship in the expression of TGF-β3 and miR-29c in leiomyoma. The TGF-β3 is a direct target of miR-29c and inhibits the expression of miR-29c through an epigenetic mechanism. The cross-talk between miR-29c and TGF-β3 provides a feed forward mechanism of fibrosis in leiomyoma.

Role of Hormones in Common Benign Uterine Lesions: Endometrial Polyps, Leiomyomas, and Adenomyosis

Leiomyoma, adenomyosis, and endometrial polyps are benign uterine disorders which seem to develop in the context of hormonal imbalances, due to steroid hormones, estrogen and progesterone, in association with various factors ranging from genetic factors to modifiable lifestyle factors. A growing body of evidence suggests that those hormones and their receptors are key modulators in the genesis and the growth of those pathologic entities. Further studies are required to understand their involvement in the pathogenesis of those lesions and their link to other factors such as extracellular matrix components, growth factors, chemokines, cytokines, and tissue repair mechanisms.

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.

The role of epidermal growth factor receptor (EGFR) common gene mutations in Iranian women with uterine fibroids

OBJECTIVE

Uterine myomas are benign uterine tumors that originate from smooth muscle cells of the myometrium. This common complication can be associated with irreversible complications, including infertility and malignancy. Better understanding of the genetic characteristics of myoma may effect on treatment. Epidermal growth factor receptor gene (EGFR) is one of the most important genes that has the major role in the pathogenesis of myoma, cell growth, differentiation, proliferation and mutagenesis. The aim of this study was to investigate EGFR common gene mutations in Iranian women with uterine fibroids.

METHODS

In this case-control study, Common EGFR gene mutations in exons 21 and exons 19 of 100 women with uterine leiomyoma as cases and 100 healthy women as controls were studied. To investigate deletion mutations of exon 19 (rs121913438) and point mutations of exon 21 (rs121434568), Tetra ARMS/PCR, ARMS and conventional PCR methods were used respectively and the results were analyzed using χ 2 test. Odds ratios (ORs) and 95% confidence intervals (CI) were estimated using logistic regression with control for age.

RESULT

Our results showed significant difference in genotypes frequency of (TT, TG, GG) for exon 21 and (WW, WD, DD) of exon 19 among cases and controls (P-Value = 5.672e-20) and (P-Value = 3.242e-15). There was a significant relationship between [G] allele and risk uterine myoma (P-Value = 3.018e-36) and the presence of [G] allele increased the chance of developing the disease OR = 0.004, 95% CI 0.001-0.013. The result also showed significant relationship between [D] allele and risk of uterine myoma (P-Value = 1.324e-15). In addition, presence of [D] allele, increased the chance of developing the disease (OR = 0.008, 95% C.I. = 0.002-0.033).

CONCLUSION

The results indicated a significant correlation between mutations in exon 19 (rs121913438) and exon 21(rs121434568) of EGFR gene and susceptibility of myoma in the study population.

Resveratrol inhibits human leiomyoma cell proliferation via crosstalk between integrin αvβ3 and IGF-1R

Leiomyomas (myomas) are the most common benign smooth muscle cell tumor of the myometrium. Resveratrol, a stilbene, has been used as an anti-inflammatory and antitumor agent. In the current study, we investigated the inhibitory effect of resveratrol on the proliferation of primary human myoma cell cultures. Resveratrol arrested cell proliferation via integrin αvβ3. It also inhibited integrin αvβ3 expression and protein accumulation. Concurrently, constitutive AKT phosphorylation in myoma cells was inhibited by resveratrol. Expressions of proapoptotic genes, such as cyclooxygenase (COX)-2, p21 and CDKN2, were induced by resveratrol in myoma cells. On the other hand, expressions of proliferative (anti-apoptotic) genes were either inhibited, as in BCL2, or unchanged, as in cyclin D1 and proliferating cell nuclear antigen (PCNA). The accumulation of insulin-like growth factor (IGF)-1 receptor (IGF-1R) was inhibited by resveratrol in primary myoma cells. IGF-1-induced cell proliferation was inhibited by co-incubation with resveratrol. Therefore, growth modulation of myoma cells occurs via mechanisms dependent on cross-talk between integrin αvβ3 and IGF-1R. Our findings suggest that resveratrol can be considered an alternative therapeutic agent for myomas.

Selective progesterone receptor modulators for fertility preservation in women with symptomatic uterine fibroids

Uterine fibroids (UFs, AKA leiomyoma) are the most important benign neoplastic threat to women's health, with costs up to hundreds of billions of health care dollars worldwide. Uterine fibroids caused morbidities exert a tremendous health toll, impacting the quality of life of women of all ethnicities, especially women of color. Clinical presentations include heavy vaginal bleeding, pelvic pain, bulk symptoms, subfertility, and obstetric complications. Current management strategies heavily lean toward surgical procedures; nonetheless, the choice of treatment is generally subject to patient's age and her desire to preserve future fertility. Women with UF who desire to maintain future fertility potential face a dilemma because of the limited treatment choices that are currently available to help them achieve that goal. Recently, ulipristal acetate the first of the promising family of oral selective progesterone receptor modulators has been approved for UF treatment in Europe, Canada, and several other countries and is under review for possible approval in the USA. In this review article, we discuss recent advances in the management options against UF with a bend toward oral effective long-term treatment alternatives who are particularly suited for those seeking to preserve their future fertility potential. We also explore the transformative concept of primary and secondary UF prevention using these new anti-UF agents. We envision a remarkable shift in the management of UF in future years from surgical/invasive treatment to orally administrated options; clearly, this potential shift will require additional intense clinical research.

A network pharmacology approach to investigate the pharmacological effects of Guizhi Fuling Wan on uterine fibroids

To investigate the pharmacological mechanism of Guizhi Fuling Wan (GFW) in the treatment of uterine fibroids, a network pharmacology approach was used. Information on GFW compounds was collected from traditional Chinese medicine (TCM) databases, and input into PharmMapper to identify the compound targets. Genes associated with uterine fibroids genes were then obtained from the GeneCards and Online Mendelian Inheritance in Man databases. The interaction data of the targets and other human proteins was also collected from the STRING and IntAct databases. The target data were input into the Database for Annotation, Visualization and Integrated Discovery for gene ontology (GO) and pathway enrichment analyses. Networks of the above information were constructed and analyzed using Cytoscape. The following networks were compiled: A compound-compound target network of GFW; a herb-compound target-uterine fibroids target network of GWF; and a compound target-uterine fibroids target-other human proteins protein-protein interaction network, which were subjected to GO and pathway enrichment analyses. According to this approach, a number of novel signaling pathways and biological processes underlying the effects of GFW on uterine fibroids were identified, including the negative regulation of smooth muscle cell proliferation, apoptosis, and the Ras, wingless-type, epidermal growth factor and insulin-like growth factor-1 signaling pathways. This network pharmacology approach may aid the systematical study of herbal formulae and make TCM drug discovery more predictable.

Effects of Combination of Estradiol with Selective Progesterone Receptor Modulators (SPRMs) on Human Breast Cancer Cells In Vitro and In Vivo

Use of estrogen or estrogen / progestin combination was an approved regimen for menopausal hormonal therapy (MHT). However, more recent patient-centered studies revealed an increase in the incidence of breast cancer in women receiving menopausal hormone therapy with estrogen plus progestin rather than estrogen alone. Tissue selective estrogen complex (TSEC) has been proposed to eliminate the progesterone component of MHT with supporting evidences. Based on our previous studies it is evident that SPRMs have a safer profile on endometrium in preventing unopposed estrogenicity. We hypothesized that a combination of estradiol (E2) with selective progesterone receptor modulator (SPRM) to exert a safer profile on endometrium will also reduce mammary gland proliferation and could be used to prevent breast cancer when used in MHT. In order to test our hypothesis, we compared the estradiol alone or in combination with our novel SPRMs, EC312 and EC313. The compounds were effectively controlled E2 mediated cell proliferation and induced apoptosis in T47D breast cancer cells. The observed effects were found comparable that of BZD in vitro. The effects of SPRMs were confirmed by receptor binding studies as well as gene and protein expression studies. Proliferation markers were found downregulated with EC312/313 treatment in vitro and reduced E2 induced mammary gland proliferation, evidenced as reduced ductal branching and terminal end bud growth in vivo. These data supporting our hypothesis that E2+EC312/EC313 blocked the estrogen action may provide basic rationale to further test the clinical efficacy of SPRMs to prevent breast cancer incidence in postmenopausal women undergoing MHT.

Gonadotropin-releasing hormone analogues inhibit leiomyoma extracellular matrix despite presence of gonadal hormones

OBJECTIVE

To determine the effect of GnRH analogues (GnRH-a) leuprolide acetate (LA) and cetrorelix acetate on gonadal hormone-regulated expression of extracellular matrix in uterine leiomyoma three-dimensional (3D) cultures.

DESIGN

Laboratory study.

SETTING

University research laboratory.

PATIENT(S)

Women undergoing hysterectomy for symptomatic leiomyomas.

INTERVENTION(S)

The 3D cell cultures, protein analysis, Western blot, immunohistochemistry.

MAIN OUTCOME MEASURE(S)

Expression of extracellular matrix proteins, collagen 1, fibronectin, and versican in leiomyoma cells 3D cultures exposed to E2, P, LA, cetrorelix acetate, and combinations for 24- and 72-hour time points.

RESULT(S)

The 3D leiomyoma cultures exposed to E2 for 24 hours demonstrated an increased expression of collagen-1 and fibronectin, which was maintained for up to 72 hours, a time point at which versican was up-regulated significantly. Although P up-regulated collagen-1 protein (1.29 ± 0.04) within 24 hours of exposure, significant increase in all extracellular matrix (ECM) proteins was observed when the gonadal hormones were used concomitantly. Significant decrease in the amount of ECM proteins was observed on use of GnRH-a, LA and cetrorelix, with 24-hour exposure. Both the compounds also significantly decreased ECM protein concentration despite the presence of E2 or both gonadal hormones.

CONCLUSION(S)

This study demonstrates that GnRH-a directly affect the gonadal hormone-regulated collagen-1, fibronectin, and versican production in their presence. These findings suggest that localized therapy with GnRH-a may inhibit leiomyoma growth even in the presence of endogenous gonadal hormone exposure, thereby providing a mechanism to eliminate the hypoestrogenic side effects associated with GnRH-a therapy.

Expulsion of a uterine myoma in a patient treated with ulipristal acetate

Description of a spontaneous expulsion of a submucosal myoma in a patient treated with ulipristal acetate.

Signaling Pathways in Leiomyoma: Understanding Pathobiology and Implications for Therapy

Uterine leiomyomas are the most common tumors of the female genital tract, affecting 50% to 70% of females by the age of 50. Despite their prevalence and enormous medical and economic impact, no effective medical treatment is currently available. This is, in part, due to the poor understanding of their underlying pathobiology. Although they are thought to start as a clonal proliferation of a single myometrial smooth muscle cell, these early cytogenetic alterations are considered insufficient for tumor development and additional complex signaling pathway alterations are crucial. These include steroids, growth factors, transforming growth factor-beta (TGF-β)/Smad; wingless-type (Wnt)/β-catenin, retinoic acid, vitamin D, and peroxisome proliferator-activated receptor γ (PPARγ). An important finding is that several of these pathways converge in a summative way. For example, mitogen-activated protein kinase (MAPK) and Akt pathways seem to act as signal integrators, incorporating input from several signaling pathways, including growth factors, estrogen and vitamin D. This underlines the multifactorial origin and complex nature of these tumors. In this review, we aim to dissect these pathways and discuss their interconnections, aberrations and role in leiomyoma pathobiology. We also aim to identify potential targets for development of novel therapeutics.

Transforming growth factor β signaling in uterine development and function

Transforming growth factor β (TGFβ) superfamily is evolutionarily conserved and plays fundamental roles in cell growth and differentiation. Mounting evidence supports its important role in female reproduction and development. TGFBs1-3 are founding members of this growth factor family, however, the in vivo function of TGFβ signaling in the uterus remains poorly defined. By drawing on mouse and human studies as a main source, this review focuses on the recent progress on understanding TGFβ signaling in the uterus. The review also considers the involvement of dysregulated TGFβ signaling in pathological conditions that cause pregnancy loss and fertility problems in women.

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.

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.

Progesterone and progesterone receptor modulators in the management of symptomatic uterine fibroids

The majority of symptomatic uterine fibroids are currently treated by surgical interventions (myomectomy or hysterectomy) or radiological treatments (uterine artery embolisation or focussed ultrasound surgery). None of these treatments is a panacea, and what is conspicuous is the lack of an effective long-term medical therapy for a disorder so common among women of reproductive age. It has been known for some time that progesterone and its receptors enhance proliferative activity in fibroids and this has raised the possibility that anti-progestins and (PRMs) could be useful in the medical management of fibroids. Some of the compounds which have produced promising results in recent clinical trials or research studies include mifepristone, CDB-4124 (telapristone), CP-8947, J-867 (asoprisnil) and CDB-2914 (ulipristal acetate or UA). UA has recently completed Phase III clinical trials with very encouraging results, and has now acquired a licence for clinical use in Europe. While considerable research has yet to be done on the long-term safety and efficacy of UA there is nevertheless good reason for optimism on the emergence of effective medical therapy in the form of UA and possibly other PRMs.

Ulipristal acetate: a novel option for the medical management of symptomatic uterine fibroids

Fibroids, the most common tumor in women of reproductive age, impact negatively on women's health and quality of life, and have significant cost implications for their management. The current mainstay treatments are surgical (myomectomy and hysterectomy) and more recently radiological (UAE and focused ultrasound surgery). Hysterectomy is curative but precludes future fertility, whereas the impact of the other treatments on reproduction is uncertain. With women in Western societies deferring childbearing to their 30s and 40s, when fibroids are most symptomatic, there is a pressing need for a uterus-sparing medical therapy that is cheap, effective, and enhances reproductive potential. Serendipity and meticulous translational research has shown that progesterone augments fibroid proliferation, raising the possibility that progesterone receptor modulators could inhibit fibroid growth; this research has culminated in the emergence of ulipristal acetate (UA), a first-in-class, oral selective progesterone receptor modulator (SPRM) that has successfully completed phase III clinical trials. It has been licensed in Western Europe for short-term clinical use prior to surgery, and has shown efficacy with a significant reduction in uterine bleeding, fibroid volume, and improved quality of life, without the side effects associated with other medications such as gonadotropin-releasing hormone (GnRH) agonists. As with all new medicines, there are concerns surrounding UA, not least its effect on the endometrium and the long-term impact on general health and reproduction. Research to date has tended to be industry led, and therefore, there is a need for researcher/clinician-led studies to address the wider issues concerning SPRMs. UA may not turn out to be the "Holy Grail" of medical therapy in the treatment of symptomatic uterine fibroids, but it has rightly given cause for a huge optimism. Further laboratory and clinical research into PRMs and related compounds will no doubt lead to more refined medications.

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.

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.

CDB-4124 does not cause apoptosis in cultured fibroid cells

OBJECTIVE

Selective progesterone receptor modulators (SPRMs), such as asoprisnil (J867) and ulipristal (CDB-2914), have been shown to reduce fibroid volume in vivo and to induce apoptosis in vitro. CDB-4124 (telapristone), a SPRM with different side groups, also reduced fibroid volume in vivo, and we hypothesized that this SPRM would also cause apoptosis in cultured fibroid cells.

METHODS

Immortalized, progesterone receptor-positive fibroid cells, known to be capable of apoptosis, were grown to 80% confluence in serum-containing media. Cells were then treated for 48 hours in serum-free media with 0, 10, 100, or 1000 nmol/L CDB-4124. Actinomycin-D and staurosporine were used as positive controls to induce apoptosis. Apoptosis was quantified using a TUNEL-fluorescein kit. Images were captured with a widefield-fluorescence microscope and analyzed using MetaMorph image analysis software. To validate results, Western blots of total cell lysates were probed for cleaved caspase-3 (c-CASP3). Experiments were repeated 3 times using independent cell batches.

RESULTS

Analysis of 19 712 nuclei indicated 14.8% ± 10.9% (mean ± SEM), 8.4% ± 4.6%, 8.2% ± 4.7%, and 9.3% ± 6.3% apoptosis in 0, 10, 100, and 1000 nmol/L CDB-4124-treated cells, respectively. There was no evidence of elevated c-CASP3 over vehicle control after treatment with CDB-4124.

CONCLUSION

CDB-4124 did not significantly induce apoptosis in cultured fibroid cells under the conditions described suggesting apoptosis may not be the main pathway responsible for CDB-4124-induced fibroid shrinkage. Variations in SPRM biological effects may be due to differences in fibroid source cells, binding kinetics, or extracellular matrix characteristics, and can be exploited in further investigations of the mechanisms of action of SPRMs in fibroid biology.

Intrauterine progestins, progesterone antagonists, and receptor modulators: a review of gynecologic applications

Intrauterine progestins, progesterone receptor modulators, and antagonists have many important current and potential gynecologic applications. This article will describe the evidence for use of intrauterine progestin for common gynecologic conditions beyond its important role in contraception. We will review the evidence for use of intrauterine progestin delivery for menorrhagia, endometriosis management, adenomyosis treatment, uterine fibroids, endometrial hyperplasia, and its concurrent use in women on hormone replacement therapy or tamoxifen.

Proinflammatory and profibrotic mediators: principal effectors of leiomyoma development as a fibrotic disorder

Leiomyomas are believed to derive from the transformation of myometrial smooth muscle cells/connective tissue fibroblasts. Although the identity of the molecule(s) that initiate such cellular transformation and orchestrate subsequent growth is still unknown, conventional evidence indicates that ovarian steroids are essential for leiomyoma growth. Ovarian steroid action in their target cell/tissue is mediated in part through local expression of various growth factors, cytokines, and chemokines. These autocrine/paracrine molecules with proinflammatory and profibrotic activities serve as major contributing factors in regulating cellular transformation, cell growth and apoptosis, angiogenesis, cellular hypertrophy, and excess tissue turnover, events central to leiomyoma growth. This review addresses the key regulatory functions of proinflammatory and profibrotic mediators and their molecular mechanisms, downstream signaling that regulates cellular events that result in transformation, and commitments of specific cells into forming a cellular environment with a possible role in development and subsequent growth of leiomyomas.

The selective progesterone receptor modulator CDB4124 inhibits proliferation and induces apoptosis in uterine leiomyoma cells

OBJECTIVE

To evaluate the effects of selective P receptor (PR) modulator CDB4124 on cell proliferation and apoptosis in cultured human uterine leiomyoma smooth muscle (LSM) cells and control myometrial smooth muscle (MSM) cells in matched uteri.

DESIGN

Laboratory research.

SETTING

Academic medical center.

PATIENT(S)

Premenopausal women (n = 12) undergoing hysterectomy for leiomyoma-related symptoms.

INTERVENTION(S)

Treatment of primary LSM and MSM cells with CDB4124 (10(-8)-10(-6) M) or vehicle for 24, 48, or 72 hours.

MAIN OUTCOME MEASURE(S)

Western blot for protein expression of proliferating cell nuclear antigen, cleaved polyadenosine 5'-diphosphate-ribose polymerase, Bcl-2, and Krüppel-like transcription factor 11; 93-(4,5-dimethylthiazol-2-yl)2,5-diphenyl tetrazolium bromide (MTT) assay to evaluate viable cell numbers; and real-time polymerase chain reaction (PCR) to quantify messenger RNA (mRNA) levels.

RESULT(S)

Treatment with CDB4124 significantly decreased levels of the proliferation marker proliferating cell nuclear antigen, the number of viable LSM cells, and the antiapoptotic protein Bcl-2. On the other hand, treatment with CDB4124 increased levels of the apoptosis marker cleaved polyadenosine 5'-diphosphate-ribose polymerase and the tumor suppressor Krüppel-like transcription factor 11 in a dose- and time-dependent manner in LSM cells. In matched MSM cells, however, CDB4124 did not affect cell proliferation or apoptosis.

CONCLUSION(S)

CDB4124 selectively inhibits proliferation and induces apoptosis in LSM but not in MSM cells.

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.

Progestins activate the AKT pathway in leiomyoma cells and promote survival

CONTEXT

Progesterone has been associated with promoting growth of uterine leiomyomas. The mechanisms involved remain unclear.

OBJECTIVE

In this study we investigated the activation of the AKT pathway and its downstream effectors, glycogen synthase kinase-3b and Forkhead box O (FOXO)-1 by progesterone as a mechanism of proliferation and survival of leiomyoma cells. Inhibitors of the AKT pathway were used to demonstrate the role of phosphatidylinositol 3-kinase, AKT, and FOXO1 in contributing to cell proliferation and apoptosis.

RESULTS

Treatment of leiomyoma cells with R5020 over a period of 72 h resulted in higher cell numbers compared with untreated cells. When cells were treated with 100 nm R5020 for 1 and 24 h, the levels of phospho(Ser 473)-AKT increased. This increase was inhibited when cells were cotreated with RU486. Treatment of leiomyoma cells with a phosphatidylinositol 3-kinase inhibitor, LY294 dramatically decreased levels of phospho(Ser 473)-AKT, despite R5020 treatment. In addition to increased phospho(Ser 473)-AKT levels, R5020 treatment resulted in an increase in phospho(Ser 256)-FOXO1 and phosphoglycogen synthase kinase-3b. Inhibition of AKT using API-59 decreased proliferation and cell viability even in the presence of R5020. Higher concentrations of API-59-induced apoptosis of leiomyoma cells, even in the presence of R5020. Psammaplysene A increased nuclear FOXO1 levels and did not affect cell proliferation but induced apoptosis of leiomyoma cells.

CONCLUSIONS

The progestin, R5020, can rapidly activate the AKT pathway. Inhibition of the AKT pathway inhibits cell proliferation and promotes apoptosis of leiomyoma cells.

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.

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.

The expression and potential regulatory function of microRNAs in the pathogenesis of leiomyoma

Leiomyomas are benign uterine tumors considered to arise from transformation of myometrial cells. What initiates the conversion of myometrial cells into leiomyoma is unknown, however cytogenetic analysis often shows occurrence of nonrandom chromosomal abnormalities that may account for their establishment. It is clear that ovarian steroids are essential for leiomyoma growth, and local expression of many autocrine/paracrine mediators serving as key regulators of cell-cycle progression, cellular hypertrophy, extracellular matrix accumulation, and apoptosis appear to play central roles in this capacity. However, the stability of the expression of these genes represents the hallmarks of leiomyoma establishment, growth, and regression. With the emergence of microRNA (miRNA) as a key regulator of gene expression stability, in this review we present evidence for the expression and potential regulatory functions on miRNAs in leiomyoma with particular emphasis on the expression of their selective target genes whose products influence various cellular activities critical to pathogenesis of leiomyomas.