High aromatase expression in uterine leiomyoma tissues of African-American women

The impact of epigallocatechin gallate, vitamin D, and D-chiro-inositol on early surgical outcomes of laparoscopic myomectomy: a pilot study

PURPOSE

A prospective investigation to assess the impact of 3 months of treatment with epigallocatechin gallate (EGCG), vitamin D and D-chiro-inositol (DCI) in the treatment of uterine fibroids (UF) with laparoscopic myomectomy as evidenced by surgical outcomes and effect on liver function.

METHODS

Non-pregnant or lactating women aged between 30 and 40 years were scheduled for laparoscopic myomectomy to treat symptoms or looking to conceive. After enrollment, patients were assigned to either (1) intervention group, assuming a total of 300 mg EGCG, 50 μg vitamin D, and 50 mg DCI divided in 2 pills per day for 3 months, or (2) control group, including untreated women scheduled to undergo laparoscopic myomectomy after 3 months.

RESULTS

91 patients completed the study. The comparison of the surgical outcomes between the intervention (n = 44) and the control (n = 47) groups revealed that the treatment significantly reduces the duration of surgery (41.93 ± 7.56 min vs 56.32 ± 10.63 min, p < 0.001). Moreover, the treatment also reduced blood loss during surgery (149.09 ± 25.40 mL vs 168.41 ± 21.34 mL, p < 0.001), resulting in treated patients having higher Hb levels at discharge 11.27 ± 0.82 mL vs 10.56 ± 0.82 mL, p < 0.01). The surgery induced an increase in AST and in total bilirubin regardless of the assigned group, and the treatment induced no change in liver function.

CONCLUSIONS

Our data suggest that EGCG plus vitamin D, and DCI could represent a safe option for women with UF scheduled for laparoscopic myomectomy, improving surgical outcomes without affecting liver functionality.

MED12 mutation activates the tryptophan/kynurenine/AHR pathway to promote growth of uterine leiomyomas

Uterine leiomyomas cause heavy menstrual bleeding, anemia, and pregnancy loss in millions of women worldwide. Driver mutations in the transcriptional mediator complex subunit 12 (MED12) gene in uterine myometrial cells initiate 70% of leiomyomas that grow in a progesterone-dependent manner. We showed a distinct chromatin occupancy landscape of MED12 in mutant MED12 (mut-MED12) versus WT-MED12 leiomyomas. Integration of cistromic and transcriptomics data identified tryptophan 2,3-dioxygenase (TDO2) as the top mut-MED12 target gene that was significantly upregulated in mut-MED12 leiomyomas when compared with adjacent myometrium and WT-MED12 leiomyomas. TDO2 catalyzes the conversion of tryptophan to kynurenine, an aryl hydrocarbon receptor (AHR) ligand that we confirmed to be significantly elevated in mut-MED12 leiomyomas. Treatment of primary mut-MED12 leiomyoma cells with tryptophan or kynurenine stimulated AHR nuclear translocation, increased proliferation, inhibited apoptosis, and induced AHR-target gene expression, whereas blocking the TDO2/kynurenine/AHR pathway by siRNA or pharmacological treatment abolished these effects. Progesterone receptors regulated the expression of AHR and its target genes. In vivo, TDO2 expression positively correlated with the expression of genes crucial for leiomyoma growth. In summary, activation of the TDO2/kynurenine/AHR pathway selectively in mut-MED12 leiomyomas promoted tumor growth and may inform the future development of targeted treatments and precision medicine.

The Influence of Race/Ethnicity on the Transcriptomic Landscape of Uterine Fibroids

The objective of this study was to determine if the aberrant expression of select genes could form the basis for the racial disparity in fibroid characteristics. The next-generation RNA sequencing results were analyzed as fold change [leiomyomas/paired myometrium, also known as differential expression (DF)], comparing specimens from White (n = 7) and Black (n = 12) patients. The analysis indicated that 95 genes were minimally changed in tumors from White (DF ≈ 1) but were significantly altered by more than 1.5-fold (up or down) in Black patients. Twenty-one novel genes were selected for confirmation in 69 paired fibroids by qRT-PCR. Among these 21, coding of transcripts for the differential expression of FRAT2, SOX4, TNFRSF19, ACP7, GRIP1, IRS4, PLEKHG4B, PGR, COL24A1, KRT17, MMP17, SLN, CCDC177, FUT2, MYO5B, MYOG, ZNF703, CDC25A, and CDCA7 was significantly higher, while the expression of DAB2 and CAV2 was significantly lower in tumors from Black or Hispanic patients compared with tumors from White patients. Western blot analysis revealed a greater differential expression of PGR-A and total progesterone (PGR-A and PGR-B) in tumors from Black compared with tumors from White patients. Collectively, we identified a set of genes uniquely expressed in a race/ethnicity-dependent manner, which could form the underlying mechanisms for the racial disparity in fibroids and their associated symptoms.

EZH2 activates Wnt/β-catenin signaling in human uterine fibroids, which is inhibited by the natural compound methyl jasmonate

OBJECTIVE

To investigate the link between EZH2 and Wnt/β-catenin signaling and its role in uterine fibroids (UFs) pathogenesis and explore the potential effect of natural compound methyl jasmonate (MJ) against UFs.

DESIGN

EZH2 overexpression or inhibition was achieved in human uterine leiomyoma (HuLM) cells using EZH2-expressing adenovirus or chemical EZH2 inhibitor (DZNep), respectively. The HuLM and normal uterine smooth muscle cells were treated with 0.1-3 mM of MJ, and several experiments were employed.

SETTING

Laboratory study.

PATIENTS(S)

None.

INTERVENTION(S)

Methyl jasmonate.

MAIN OUTCOME MEASURE(S)

Protein expression of EZH2, β-catenin, and proliferating cell nuclear antigen (PCNA) was measured by Western blot as well as gene expression alterations of Wnt ligands (Wnt5A, Wnt5b, and Wnt9A), WISP1, CTNNB1, and its responsive gene PITX2 using quantitative real-time polymerase chain reaction. The protein and ribonucleic acid (RNA) levels of several markers were measured in MJ-treated or untreated HuLM cells, including EZH2 and β-catenin, extracellular matrix markers collagen type 1 (COL1A1) and fibronectin (FN), proliferation markers cyclin D1 (CCND1) and PCNA, tumor suppressor marker p21, and apoptotic markers (BAX, cytochrome c, and cleaved caspase 3).

RESULT(S)

EZH2 overexpression significantly increased the gene expression of several Wnt ligands (PITX2, WISP1, WNT5A, WNT5B, and WNT9A), which increased nuclear translocation of β-catenin and PCNA and eventually HuLM cell proliferation. EZH2 inhibition blocked Wnt/β-catenin signaling activation where the aforementioned genes significantly decreased as well as PCNA, cyclin D1, and PITX2 protein expression compared with those in untreated HuLM. Methyl jasmonate showed a potent antiproliferative effect on HuLM cells in a dose- and time-dependent manner. Interestingly, the dose range (0.1-0.5 mM) showed a selective growth inhibitory effect on HuLM cells, not on normal uterine smooth muscle cells. Methyl jasmonate treatment at 0.5 mM for 24 hours significantly decreased both protein and RNA levels of EZH2, β-catenin, COL1A1, FN, CCND1, PCNA, WISP1, and PITX2 but increased the protein levels of p21, BAX, cytochrome, c and cleaved caspase 3 compared with untreated HuLM. Methyl jasmonate-treated cells exhibited down-regulation in the RNA expression of 36 genes, including CTNNB1, CCND1, Wnt5A, Wnt5B, and Wnt9A, and up-regulation in the expression of 34 genes, including Wnt antagonist genes WIF1, PRICKlE1, and DKK1 compared with control, confirming the quantitative real-time polymerase chain reaction results.

CONCLUSION(S)

Our studies provide a novel link between EZH2 and the Wnt/β-catenin signaling pathway in UFs. Targeting EZH2 with MJ interferes with the activation of wnt/β-catenin signaling in our model. Methyl jasmonate may offer a promising therapeutic option as a nonhormonal and cost-effective treatment against UFs with favorable clinical utility, pending proven safe and efficient in human clinical trials.

A View on Uterine Leiomyoma Genesis through the Prism of Genetic, Epigenetic and Cellular Heterogeneity

Uterine leiomyomas (ULs), frequent benign tumours of the female reproductive tract, are associated with a range of symptoms and significant morbidity. Despite extensive research, there is no consensus on essential points of UL initiation and development. The main reason for this is a pronounced inter- and intratumoral heterogeneity resulting from diverse and complicated mechanisms underlying UL pathobiology. In this review, we comprehensively analyse risk and protective factors for UL development, UL cellular composition, hormonal and paracrine signalling, epigenetic regulation and genetic abnormalities. We conclude the need to carefully update the concept of UL genesis in light of the current data. Staying within the framework of the existing hypotheses, we introduce a possible timeline for UL development and the associated key events—from potential prerequisites to the beginning of UL formation and the onset of driver and passenger changes.

Differential Expression of MED12-Associated Coding RNA Transcripts in Uterine Leiomyomas

Recent studies have demonstrated that somatic MED12 mutations in exon 2 occur at a frequency of up to 80% and have a functional role in leiomyoma pathogenesis. The objective of this study was to elucidate the expression profile of coding RNA transcripts in leiomyomas, with and without these mutations, and their paired myometrium. Next-generation RNA sequencing (NGS) was used to systematically profile the differentially expressed RNA transcripts from paired leiomyomas (n = 19). The differential analysis indicated there are 394 genes differentially and aberrantly expressed only in the mutated tumors. These genes were predominantly involved in the regulation of extracellular constituents. Of the differentially expressed genes that overlapped in the two comparison groups, the magnitude of change in gene expression was greater for many genes in tumors bearing MED12 mutations. Although the myometrium did not express MED12 mutations, there were marked differences in the transcriptome landscape of the myometrium from mutated and non-mutated specimens, with genes regulating the response to oxygen-containing compounds being most altered. In conclusion, MED12 mutations have profound effects on the expression of genes pivotal to leiomyoma pathogenesis in the tumor and the myometrium which could alter tumor characteristics and growth potential.

Mono-(2-ethyl-5-hydroxyhexyl) phthalate promotes uterine leiomyoma cell survival through tryptophan-kynurenine-AHR pathway activation

Uterine leiomyoma is the most common tumor in women and causes severe morbidity in 15 to 30% of reproductive-age women. Epidemiological studies consistently indicate a correlation between leiomyoma development and exposure to endocrine-disrupting chemical phthalates, especially di-(2-ethylhexyl) phthalate (DEHP); however, the underlying mechanisms are unknown. Here, among the most commonly encountered phthalate metabolites, we found the strongest association between the urine levels of mono(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), the principal DEHP metabolite, and the risk of uterine leiomyoma diagnosis (n = 712 patients). The treatment of primary leiomyoma and smooth muscle cells (n = 29) with various mixtures of phthalate metabolites, at concentrations equivalent to those detected in urine samples, significantly increased cell viability and decreased apoptosis. MEHHP had the strongest effects on both cell viability and apoptosis. MEHHP increased cellular tryptophan and kynurenine levels strikingly and induced the expression of the tryptophan transporters SLC7A5 and SLC7A8, as well as, tryptophan 2,3-dioxygenase (TDO2), the key enzyme catalyzing the conversion of tryptophan to kynurenine that is the endogenous ligand of aryl hydrocarbon receptor (AHR). MEHHP stimulated nuclear localization of AHR and up-regulated the expression of CYP1A1 and CYP1B1, two prototype targets of AHR. siRNA knockdown or pharmacological inhibition of SLC7A5/SLC7A8, TDO2, or AHR abolished MEHHP-mediated effects on leiomyoma cell survival. These findings indicate that MEHHP promotes leiomyoma cell survival by activating the tryptophan-kynurenine-AHR pathway. This study pinpoints MEHHP exposure as a high-risk factor for leiomyoma growth, uncovers a mechanism by which exposure to environmental phthalate impacts leiomyoma pathogenesis, and may lead to the development of novel druggable targets.

HYSTEROSCOPIC MYOMECTOMY

Leiomyomas are the most common pelvic tumors. Submucosal fibroids are a common cause of abnormal bleeding and infertility. Hysteroscopic myomectomy is the definitive management of symptomatic submucosal fibroids, with high efficacy and safety. Several techniques have been introduced over time and will be covered in depth in this manuscript. Advances in optics, fluid management, electrosurgery, smaller diameter scopes, and tissue removal systems, along with improved training have contributed to improving the safety and efficiency of hysteroscopic myomectomy.

Cadmium Ecotoxic Effects on Embryonic Dmrt1 and Aromatase Expression in Chrysemys picta Turtles May Implicate Changes in DNA Methylation

Temperature-dependent sex determination (TSD) decides the sex fate of an individual based on incubation temperature. However, other environmental factors, such as pollutants, could derail TSD sexual development. Cadmium is one such contaminant of soils and water bodies known to affect DNA methylation, an epigenetic DNA modification with a key role in sexual development of TSD vertebrate embryos. Yet, whether cadmium alters DNA methylation of genes underlying gonadal formation in turtles remains unknown. Here, we investigated the effects of cadmium on the expression of two gene regulators of TSD in the painted turtle, Chrysemys picta, incubated at male-producing and female-producing temperatures using qPCR. Results revealed that cadmium alters transcription of Dmrt1 and aromatase, overriding the normal thermal effects during embryogenesis, which could potentially disrupt the sexual development of TSD turtles. Results from a preliminary DNA methylation-sensitive PCR assay implicate changes in DNA methylation of Dmrt1 as a potential cause that requires further testing (aromatase methylation assays were precluded).

Comprehensive Review of Uterine Fibroids: Developmental Origin, Pathogenesis, and Treatment

Uterine fibroids are benign monoclonal neoplasms of the myometrium, representing the most common tumors in women worldwide. To date, no long-term or noninvasive treatment option exists for hormone-dependent uterine fibroids, due to the limited knowledge about the molecular mechanisms underlying the initiation and development of uterine fibroids. This paper comprehensively summarizes the recent research advances on uterine fibroids, focusing on risk factors, development origin, pathogenetic mechanisms, and treatment options. Additionally, we describe the current treatment interventions for uterine fibroids. Finally, future perspectives on uterine fibroids studies are summarized. Deeper mechanistic insights into tumor etiology and the complexity of uterine fibroids can contribute to the progress of newer targeted therapies.

The Impact of Uterine Fibroids on Fertility: How the Uncertainty Widens the Gap in Reproductive Outcomes in Black Women

Uterine fibroids (UFs) are the most common pelvic tumor in women. While the decreased quality of life and significant morbidity has been implicated with UFs, several important questions regarding the effect of UFs on reproductive outcomes remain unanswered. Furthermore, there is a disproportionate impact of UFs in Black women, in whom these tumors are known to be more common and more severe. The racial difference in UF burden is heightened during prime reproductive years, during which Black women undergo surgical intervention at an astoundingly increased rate compared to other races. Despite this, Black women are underrepresented in UF and treatment outcome research, and thus the uncertainty of the impact of UFs and UF treatment on fertility and pregnancy outcomes in this population is less defined. The purpose of this review article is to discuss recent findings in the literature regarding the impact of uterine UFs on reproductive outcomes with a primary focus on the implications for Black women. Additionally, we briefly discuss the importance of increased UF research funding and investigation and propose actionable items to help increase the representation of Black women in UF research.

Apoplectic leiomyomas: does ethnicity make a difference? a clinicopathologic study

Apoplectic leiomyomas-benign uterine leiomyomas with morphologic changes including hemorrhage, hypercellularity, mitotic activity, nuclear atypia, and even necrosis-can be difficult to distinguish from uterine leiomyosarcomas. Apoplectic leiomyomas have been associated with hormonal therapy; however, the relationship between apoplectic leiomyomas, hormones, and ethnicity has not received much attention in the literature. We evaluated the relationship of hormonal therapy and ethnicity in 869 women with uterine leiomyomas, 136 of which qualified as apoplectic leiomyomas.Apoplectic leiomyomas were observed in 23.3% (49/210) of women exposed to hormonal therapy compared to 13.2% (87/659) of women not exposed to hormonal therapy (p < 0.0001). Women taking ethinyl estradiol/norethindrone (Lo-Estrin), leuprolide, and medroxyprogesterone were significantly more likely to have apoplectic leiomyomas compared to women taking other hormonal therapies. Apoplectic leiomyomas were observed in 28.9% (44/152) of African-American women compared to 12.4% (79/639) of Caucasian women (p < 0.0001), and this difference remained statistically significant regardless of hormone use. Apoplectic leiomyomas were observed in 22.1% (77/349) of women ≤ 45 years of age compared to 11.3% (59/520) of women > 45 years of age (p < 0.0001), and this difference remained statistically significant regardless of hormone use.This is the largest study to date examining apoplectic leiomyomas in women on known hormonal therapy compared to women with uterine leiomyomas, but not on hormonal therapy. Information about hormonal therapy, ethnicity, and age can be helpful in the diagnostic interpretation of apoplectic leiomyoma.

Current approaches to overcome the side effects of GnRH analogs in the treatment of patients with uterine fibroids

Introduction: Uterine fibroids (UFs) are the most prevalent benign neoplastic threat originating from myometria of reproductive age women, with a profound financial load valued in hundreds of billions of dollars. Unfortunately, there is no curative treatment so far except surgery and available pharmacological treatments are restricted for short-term treatment options. Thus, there is a large unmet need in the UF space for noninvasive therapeutics.Areas covered: The authors reviewed the literature available for the utility of gonadotropin-releasing hormone (GnRH) analogs in women with UFs. We also focused on clinical studies exploring the therapeutic benefits of novel oral non-peptide GnRH antagonists that were recently approved by the U.S. Food and Drug Administration (FDA) in combination with estradiol/norethindrone acetate for the management of heavy menstrual bleeding associated with UFs in premenopausal women.Expert opinion: The results regarding the efficacy of new-generation oral GnRH-antagonists, such as elagolix, relugolix and linzagolix, are promising and offer potential prospect for the future therapy of UFs. However, these antagonists must be combined with hormonal add-back therapy to minimize the resultant hypoestrogenic side effects such as bone loss.

Inositols: From Established Knowledge to Novel Approaches

Myo-inositol (myo-Ins) and D-chiro-inositol (D-chiro-Ins) are natural compounds involved in many biological pathways. Since the discovery of their involvement in endocrine signal transduction, myo-Ins and D-chiro-Ins supplementation has contributed to clinical approaches in ameliorating many gynecological and endocrinological diseases. Currently both myo-Ins and D-chiro-Ins are well-tolerated, effective alternative candidates to the classical insulin sensitizers, and are useful treatments in preventing and treating metabolic and reproductive disorders such as polycystic ovary syndrome (PCOS), gestational diabetes mellitus (GDM), and male fertility disturbances, like sperm abnormalities. Moreover, besides metabolic activity, myo-Ins and D-chiro-Ins deeply influence steroidogenesis, regulating the pools of androgens and estrogens, likely in opposite ways. Given the complexity of inositol-related mechanisms of action, many of their beneficial effects are still under scrutiny. Therefore, continuing research aims to discover new emerging roles and mechanisms that can allow clinicians to tailor inositol therapy and to use it in other medical areas, hitherto unexplored. The present paper outlines the established evidence on inositols and updates on recent research, namely concerning D-chiro-Ins involvement into steroidogenesis. In particular, D-chiro-Ins mediates insulin-induced testosterone biosynthesis from ovarian thecal cells and directly affects synthesis of estrogens by modulating the expression of the aromatase enzyme. Ovaries, as well as other organs and tissues, are characterized by a specific ratio of myo-Ins to D-chiro-Ins, which ensures their healthy state and proper functionality. Altered inositol ratios may account for pathological conditions, causing an imbalance in sex hormones. Such situations usually occur in association with medical conditions, such as PCOS, or as a consequence of some pharmacological treatments. Based on the physiological role of inositols and the pathological implications of altered myo-Ins to D-chiro-Ins ratios, inositol therapy may be designed with two different aims: (1) restoring the inositol physiological ratio; (2) altering the ratio in a controlled way to achieve specific effects.

Uterine Fibroids and Infertility

Infertility is a disease of the reproductive system defined by the failure to achieve a clinical pregnancy after 12 months or more of regular unprotected sexual intercourse. Uterine fibroids are the most common tumor in women, and their prevalence is high in patients with infertility. Fibroids may be the sole cause of infertility in 2–3% of women. Depending on their location in the uterus, fibroids have been implicated in recurrent pregnancy loss as well as infertility. Pregnancy and live birth rates appear to be low in women with submucosal fibroids; their resection has been shown to improve pregnancy rates. In contrast, subserosal fibroids do not affect fertility outcomes and their removal does not confer any benefit. Intramural fibroids appear to reduce fertility, but recommendations concerning their treatment remain unclear. Myomectomy should be discussed individually with the patient; other potential symptoms such as dysmenorrhea or bleeding disorders should be included in the indication for surgery.

A-kinase anchoring protein 13 interacts with the vitamin D receptor to alter vitamin D-dependent gene activation in uterine leiomyoma cells

OBJECTIVE

To determine if A-kinase anchoring protein 13 (AKAP13) interacts with the vitamin D receptor (VDR) to alter vitamin D-dependent signaling in fibroid cells. Uterine leiomyomas (fibroids) are characterized by a fibrotic extracellular matrix and are associated with vitamin D deficiency. Treatment with vitamin D (1,25-dihydroxyvitamin D₃) reduces fibroid growth and extracellular matrix gene expression. A-kinase anchoring protein 13 is overexpressed in fibroids and interacts with nuclear hormone receptors, but it is not known whether AKAP13 may interact with the VDR to affect vitamin D signaling in fibroids.

DESIGN

Laboratory studies.

SETTING

Translational science laboratory.

INTERVENTION(S)

Human immortalized fibroid or myometrial cells were treated with 1,25-hydroxyvitamin D₃ (1,25(OH)₂D₃) and transfected using expression constructs for AKAP13 or AKAP13 mutants, RhoQL, C3 transferase, or small interfering ribonucleic acids (RNAs).

MAIN OUTCOME MEASURE(S)

Messenger ribonucleic acid (mRNA) levels of AKAP13, fibromodulin, and versican as measured by quantitative real-time polymerase chain reaction. Glutathione S-transferase-binding assays. Vitamin D-dependent gene activation as measured by luciferase assays.

RESULT(S)

1,25(OH)₂D₃ resulted in a significant reduction in mRNA levels encoding AKAP13, versican, and fibromodulin. Small interfering RNA silencing of AKAP13 decreased both fibromodulin and versican mRNA levels. Glutathione S-transferase-binding assays revealed that AKAP13 bound to the VDR through its nuclear receptor interacting region. Cotransfection of AKAP13 and VDR significantly reduced vitamin D-dependent gene activation. RhoA pathway inhibition partially relieved repression of vitamin D-dependent gene activation by AKAP13.

CONCLUSION(S)

These data suggest that AKAP13 inhibited the vitamin D receptor activation by a mechanism that required, at least in part, RhoA activation.

Menstruation: science and society

Women's health concerns are generally underrepresented in basic and translational research, but reproductive health in particular has been hampered by a lack of understanding of basic uterine and menstrual physiology. Menstrual health is an integral part of overall health because between menarche and menopause, most women menstruate. Yet for tens of millions of women around the world, menstruation regularly and often catastrophically disrupts their physical, mental, and social well-being. Enhancing our understanding of the underlying phenomena involved in menstruation, abnormal uterine bleeding, and other menstruation-related disorders will move us closer to the goal of personalized care. Furthermore, a deeper mechanistic understanding of menstruation-a fast, scarless healing process in healthy individuals-will likely yield insights into a myriad of other diseases involving regulation of vascular function locally and systemically. We also recognize that many women now delay pregnancy and that there is an increasing desire for fertility and uterine preservation. In September 2018, the Gynecologic Health and Disease Branch of the Eunice Kennedy Shriver National Institute of Child Health and Human Development convened a 2-day meeting, "Menstruation: Science and Society" with an aim to "identify gaps and opportunities in menstruation science and to raise awareness of the need for more research in this field." Experts in fields ranging from the evolutionary role of menstruation to basic endometrial biology (including omic analysis of the endometrium, stem cells and tissue engineering of the endometrium, endometrial microbiome, and abnormal uterine bleeding and fibroids) and translational medicine (imaging and sampling modalities, patient-focused analysis of menstrual disorders including abnormal uterine bleeding, smart technologies or applications and mobile health platforms) to societal challenges in health literacy and dissemination frameworks across different economic and cultural landscapes shared current state-of-the-art and future vision, incorporating the patient voice at the launch of the meeting. Here, we provide an enhanced meeting report with extensive up-to-date (as of submission) context, capturing the spectrum from how the basic processes of menstruation commence in response to progesterone withdrawal, through the role of tissue-resident and circulating stem and progenitor cells in monthly regeneration-and current gaps in knowledge on how dysregulation leads to abnormal uterine bleeding and other menstruation-related disorders such as adenomyosis, endometriosis, and fibroids-to the clinical challenges in diagnostics, treatment, and patient and societal education. We conclude with an overview of how the global agenda concerning menstruation, and specifically menstrual health and hygiene, are gaining momentum, ranging from increasing investment in addressing menstruation-related barriers facing girls in schools in low- to middle-income countries to the more recent "menstrual equity" and "period poverty" movements spreading across high-income countries.

Role of DNA damage and repair mechanisms in uterine fibroid/leiomyomas: a review

There has been a significant annual increase in the number of cases of uterine leiomyomas or fibroids (UF) among women of all races and ages across the world. A fortune is usually spent by the healthcare sector for fibroid-related treatments and management. Molecular studies have established the higher mutational heterogeneity in UF as compared to normal myometrial cells. The contribution of DNA damage and defects in repair responses further increases the mutational burden on the cells. This in turn leads to genetic instability, associated with cancer risk and other adverse reproductive health outcomes. Such and many more growing bodies of literature have highlighted the genetic/molecular, biochemical and clinical aspects of UF; none the less there appear to be a lacuna bridging the bench to bed gap in addressing and preventing this disease. Presented here is an exhaustive review of not only the molecular mechanisms underlying the predisposition to the disease but also possible strategies to effectively diagnose, prevent, manage, and treat this disease.

3-(Para-fluorobenzoyl)-propionic acid; a metabolite of haloperidol, reversed oestradiol valerate-induced uterine hyperplasia via modulation of oestrogen receptor signalling pathways in female Wistar rats

Background 3-(Para-fluorobenzoyl)-propionic acid (3PFBPA) is one of the metabolites of haloperidol used in the treatment of psychotic disorders. 3PFBPA is an inhibitor of mitogen-activated protein kinase (MAPK), implicated in the development of uterine fibroids (UFs) and cellular proliferation. In this study, the effect of 3PFBPA on oestradiol valerate (OV)-induced uterine hyperplasia was investigated. Methods Uterine hyperplasia was induced by intraperitoneal (i.p.) injection of OV (3 mg/kg for 12 weeks). Expression of oestrogen receptor (ER) α, β-catenin and E-cadherin were investigated via immunohistochemistry. The histology and fibroblast cell count/μm2 (using histomorphometry) were carried out. Results There was a significant increase in the levels of oestrogen, progesterone and total cholesterol in the OV-treated group when compared with the control, assessed by enzyme-linked immunosorbent assay (ELISA) kits. Oestrogen and total cholesterol were markedly reduced in the OV + 3PFBPAtreated group when compared with the OV-treated group. The OV-induced overexpression of β-catenin and ER were also ameliorated by 3PFBPA. Also, the loss of E-cadherin function in the OV-treated group was restored by 3PFBPA. The histological findings and histomorphometric results revealed the presence of uterine hyperplasia in the OV-treated rats which was significantly reversed by 3PFBPA. Histological studies revealed a protective role against OV-induced uterine damage that was found after OV + 3PFBPA co-administration. Conclusion This study demonstrated that 3PFBPA ameliorates OV-induced uterine hyperplasia in the female Wistar rat model. The findings warrant further investigation of the antifibrotic effects of 3PFBPA in humans.

Epidemiology and management of uterine fibroids

Uterine leiomyomas are one of the most common and yet understudied diseases in women. These tumors, commonly known as fibroids, affect women mainly during their reproductive years and are diagnosed in up to 70% of white women and more than 80% of women of African ancestry during their lifetime. This disease has a profound impact on health care delivery and costs worldwide. Though most women with fibroids are asymptomatic, approximately 30% of them will present with severe symptoms which can include abnormal uterine bleeding, anemia, pelvic pain and pressure, back pain, urinary frequency, constipation, or infertility, and will require intervention. Furthermore, fibroids have been associated with poor obstetrical outcomes. The current options for symptomatic fibroid treatment include expectant, medical, and surgical management, and interventional radiology procedures. This article reviews the recent progress and available management strategies for uterine fibroids and highlights areas where further research is needed to find new therapeutic targets and better personalize treatments.

Isoliquiritigenin Suppresses E2-Induced Uterine Leiomyoma Growth through the Modulation of Cell Death Program and the Repression of ECM Accumulation

Uterine leiomyomas, also known as fibroids, are common and prevalent in women of reproductive age. In this study, the effect of Isoliquiritigenin (ISL), a licorice flavonoid, on the anti-proliferation of uterine leiomyoma was investigated. We found that the survival of uterine leiomyoma ELT3 cells and primary uterine smooth muscle (UtSMC) cells was reduced by treatment with ISL alone or with ISL plus estradiol (E2). Cell cycles were arrested through the reduction of G2/M- and S-phase populations in ELT3 and UtSMC cells, respectively. Furthermore, increased sub-G1 phase and nucleus condensation were observed in ELT3 cells but not in UtSMC cells. Co-treatment of ELT3 cells with E2 and ISL inhibited ERK1/2 activation, whereas p38 and c-Jun N-terminal kinase (JNK) activation was enhanced. Moreover, ISL-induced apoptosis and autophagy cell death in ELT3 cells were observed. Serum E2 and P4 levels were reduced in a E2-enhanced uterine myometrium hyperplasia mouse model by ISL treatment, which contributed to the downregulation of the expression of extracellular matrix (ECM) associated proteins and matrix metalloproteinase (MMPs). Taken together, these results showed that ISL exerted a higher effect on the inhibition of estrogen-induced uterine leiomyoma growth for both in vitro and in vivo ECM accumulation, demonstrating its potential as a new option for treatment of uterine leiomyoma.

The Role of Tumor Necrosis Factor α in the Biology of Uterine Fibroids and the Related Symptoms

Uterine fibroids (UFs) are the most common benign tumors of the female genital tract. The incidence of UFs has been estimated at 25⁻80% depending on selected population. The pathophysiology of UFs remains poorly understood. The transformation of smooth muscle cells of the uterus into abnormal, immortal cells, capable of clonal division, is the main component of all pathways leading to UF tumor formation and tumor necrosis factor α (TNF-α) is believed to be one of the key factors in this field. TNF-α is a cell signaling protein involved in systemic inflammation and is one of the cytokines responsible for the acute phase reaction. This publication presents current data about the role of tumor necrosis factor α in the biology of UFs and the related symptoms. TNF-α is an extremely important cytokine associated with the biology of UFs, UF-related symptoms and complaints. Its concentration has been proven to be elevated in women with clinically symptomatic UFs. The presented data suggest the presence of an "inflammation-like" state in women with UFs where TNF-α is a potent inflammation inducer. The origin of numerous symptoms reported by women with UFs can be traced back to the TNF-α influence. Nevertheless, our knowledge on this subject remains limited and TNF-α dependent pathways in UF pathophysiology should be investigated further.

Leiomyomatous uterus and preterm birth: an exposed/unexposed monocentric cohort study

BACKGROUND

The risk of preterm birth may increase in the presence of uterine leiomyomas during pregnancy. Whether myomectomy abrogates this risk has never been studied.

OBJECTIVE

Our aim was to evaluate the association between the presence of uterine leiomyomas during pregnancy and preterm birth and, if an association exists, to evaluate its persistence in case of a history of myomectomy.

STUDY DESIGN

This exposed/unexposed monocentric retrospective cohort study included all women with singleton pregnancies delivering >22 weeks in a tertiary university hospital maternity unit from January 2011 through September 2015. Women with a leiomyomatous uterus were compared to women with no myomas. Women in the leiomyomatous uterus group were women with uterine leiomyoma(s) during pregnancy (≥1 leiomyoma, measuring ≥20 mm or multiple leiomyomas whatever the size) seen on at least 1 obstetric ultrasound without history of myomectomy, or women with a history of myomectomy (removal of ≥1 leiomyoma, measuring ≥20 mm or multiple leiomyomas whatever the size) by hysteroscopy, laparoscopy, or laparotomy with or without persistent leiomyomas. The association between leiomyomatous uterus and preterm birth was assessed through univariate and multivariable logistic regression.

RESULTS

Among the 19,866 women in the cohort, 301 (1.5%) had a leiomyomatous uterus (154 unoperated women and 147 operated women). The rate of premature delivery was 12.0% in the leiomyomatous uterus group and 8.4% in the nonleiomyomatous uterus group. After adjusting for the risk factors for preterm birth, leiomyomatous uterus was significantly associated with preterm birth (adjusted odds ratio, 2.5; 95% confidence interval, 1.7-3.7). This association was significant for unoperated women (adjusted odds ratio, 2.7; 95% confidence interval, 1.6-4.6) as well as operated women (adjusted odds ratio, 2.3; 95% confidence interval, 1.3-3.9) when compared to the nonleiomyomatous uterus group.

CONCLUSION

Uterine leiomyomas are associated with preterm birth and this association persists after myomectomy.

Variation in MicroRNA Expression Profile of Uterine Leiomyoma with Endometrial Cavity Distortion and Endometrial Cavity Non-Distortion

The expression profile of microRNA (miRNA) in uterine leiomyoma (UL) cells is different from that in normal uterine myometrial (UM) cells. The effect of UL cells on uterine receptivity might vary according to their ability to distort the uterine endometrial cavity. However, the variation in miRNA expression profiles between endometrial cavity-distorting leiomyoma (ECDL) and endometrial cavity non-distorting leiomyoma (ECNDL) cells remains unknown. This study aimed to elucidate whether the expression profile of miRNAs in ECDL cells is dissimilar to that of ECNDL cells in uterus. Pelviscopic myomectomy was performed to obtain tissue samples of UL and their corresponding normal UM tissues (matched) from patients with UL (n = 26), among whom women with ECNDL and ECDL numbered 15 and 11, respectively. The relative expression of hsa-miR-15b, -29a, -29b, -29c, -197, and -200c as well as the candidate target genes in UL cells was compared to those in the matched UM cells using qRT-PCR to assess their ability to cause ECD. The spatial expression of miRNAs and target genes in the UL tissues was analyzed using in situ hybridization. Target gene expression was analyzed using qPCR after transfection with the mimics and inhibitors of miRNAs in UL cells. The relative expression level of miR-15b was upregulated, and the relative expression levels of miR-29a, -29b, -29c, -197, and -200c were downregulated in UL cells compared to those in UM cells. The relative expression levels of progesterone receptor, estrogen receptor, and matrix metalloproteinases (MMPs) were upregulated in UL cells compared to those in UM cells. The relative expression levels of miR-29c and -200c were downregulated, and the relative expression levels of estrogen receptor, MMPs and tissue inhibitors of metalloproteinases (TIMPs) were upregulated in ECDL cells compared to those in ECNDL cells. The expression profile of miRNAs in UL cells varied with respect to the occurrence or absence of endometrial cavity distortion. The biochemical properties of UL might be regulated by miRNAs in order to alter their effect on structural homeostasis of the uterus.

Effect of pregnancy on recurrence of symptomatic uterine myomas in women who underwent myomectomy

BACKGROUND

There is no consensus in the literature regarding risk factors associated with recurrence of uterine leiomyomas. In this study, we evaluated the factors that affect the recurrence of uterine leiomyomas in women who underwent laparotomic or endoscopic myomectomy.

METHODS

This retrospective study included 378 patients that underwent myomectomy. Patient follow-up ranged from two to eight years, and they were classified according to the recurrence of myoma uteri. Age, gravidity, parity, presenting complaints, prior surgery, comorbidity, smoking status, intraoperative and postoperative features, and Ca 125 levels were obtained from the hospital records and patient files.

RESULTS

Recurrence was detected in 67 women (17.72 %). No statistically significant differences were observed in the demographic data and past obstetric history between the recurrent and non-recurrent groups. The number of myomas was higher in the recurrence group as compared to the non-recurrence group [2 (range: 1-41) vs 1 (1-19), respectively, p =0.022]. Pregnancy rates were statistically higher in the recurrence group as compared to the non- recurrence group (17.9 % vs 7.1 %, respectively, p =0.005). Pregnancy after myomectomy increased the risk of recurrence by 2.8-fold (odds ratio: 2.87; 95 % confidence interval: 1.34-6.13). No significant differences were observed between the two groups regarding the surgical route, fibroid size, uterine location, and position of the myomas in the uterus.

CONCLUSION

Women who had more than two myomas should be informed of the possibility of recurrent myoma uteri. Additionally, pregnancy in women who previously had a myomectomy was found to be a risk factor for recurrence of the uterine myoma. HIPPOKRATIA 2018, 22(3): 122-126.

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.

Current medical treatment of uterine fibroids

Uterine fibroids (leiomyomas or myomas), benign monoclonal tumors, are the most common benign tumors in women. Heavy or prolonged menstrual bleeding, abnormal uterine bleeding, resultant anemia, pelvic pain, infertility, and/or recurrent pregnancy loss are generally associated with uterine fibroids. Although curative treatment of this tumor relies on surgical therapies, medical treatments are considered the first-line treatment to preserve fertility and avoid or delay surgery. The aim of this review is to provide available and emerging medical treatment options for symptomatic uterine fibroids. Literature review and consensus of expert opinion. Many uterine fibroids are asymptomatic and require no intervention, although it is advisable to follow-up patients to document stability in size and growth. Fibroid-associated symptoms include heavy menstrual bleeding and pain or pelvic discomfort. The association between infertility and fibroids increases with age. Treatment options for symptomatic uterine fibroids - include medical, surgical, and radiologically guided interventions. Various medical therapies are now available for women with uterine fibroids, although each therapy has its own advantages and disadvantages. Currently, gonadotrophin-releasing hormone (GnRH) agonists and selective progesterone receptor modulators (SPRMs) are the most effective medical therapies, with the most evidence to support their reduction of fibroid volume and symptomatic improvement in menstrual bleeding. The choice of treatment depends on the patient's personal treatment goals, as well as efficacy and need for repeated interventions.

Clinical, pathologic, cytogenetic, and molecular profiling in self-identified black women with uterine leiomyomata

Black women are disproportionately affected by uterine leiomyomata (UL), or fibroids, compared to other racial groups, having a greater lifetime risk of developing UL and an earlier age of diagnosis. In order to elucidate molecular and genetic mechanisms responsible for the increased prevalence and morbidity associated with UL in black women, clinical, pathologic, cytogenetic, and select molecular profiling (MED12 mutation analysis) of 75 self-reported black women undergoing surgical treatment for UL was performed. Our observations are broadly representative of previous cytogenetic studies of UL: karyotypically abnormal tumors were detected in 30.7% of women and 17.4% of analyzed tumors. No notable association was observed between race and increased occurrence of cytogenetic abnormalities that might contribute to any population-specific morbidity or prevalence rate. Our data on MED12 mutation analyses (73.2% of tumors harbored a MED12 mutation) provide additional support for a significant role of MED12 in tumorigenesis. Although the effect of MED12-mediated tumorigenesis appears significant irrespective of race, other genetic events such as the distribution of karyotypic abnormalities appear differently in black women. This case series indicates that presently recognized genetic and molecular characteristics of UL do not appear to explain the increased prevalence and morbidity of UL in black women.

Oestrogen Receptor-α binds the FOXP3 promoter and modulates regulatory T-cell function in human cervical cancer

Oestrogen controls Foxp3 expression in regulatory T cells (Treg cells) via a mechanism thought to involve oestrogen receptor alpha (ERα), but the molecular basis and functional impact of ERα signalling in Treg cells remain unclear. We report that ERα ligand oestradiol (E2) is significantly increased in human cervical cancer (CxCa) tissues and tumour-infiltrating Treg cells (CD4+CD25hiCD127low), whereas blocking ERα with the antagonist ICI 182,780 abolishes FOXP3 expression and impairs the function of CxCa infiltrating Treg cells. Using a novel approach of co-immunoprecipitation with antibodies to E2 for capture, we identified binding of E2:ERα complexes to FOXP3 protein in CxCa-derived Treg cells. Chromatin immunoprecipitation analyses of male blood Treg cells revealed ERα occupancy at the FOXP3 promoter and conserved non-coding DNA elements 2 and 3. Accordingly, computational analyses of the enriched regions uncovered eight putative oestrogen response elements predicted to form a loop that can activate the FOXP3 promoter. Together, these data suggest that E2-mediated ERα signalling is critical for the sustenance of FOXP3 expression and Treg cell function in human CxCa via direct interaction of ERα with FOXP3 promoter. Overall, our work gives a molecular insight into ERα signalling and highlights a fundamental role of E2 in controlling human Treg cell physiology.

Alternative Oral Agents in Prophylaxis and Therapy of Uterine Fibroids-An Up-to-Date Review

Uterine fibroids (UFs) are the most common tumors of the female genital tract. The effect of UFs on the quality of life and the overall cost of treatment are significant issues worldwide. Tumor size and location are the two specific factors which influence the occurrence of symptoms, the need for, and method of, treatment (some tumors require surgery while some can be treated with selected drugs). Primary prevention and treatment of early UF disease are worthy goals that might have a great impact on health care systems. Several treatments and prophylactic methods can be used in this endeavor. This publication presents current data about lesser-known substances which may have a beneficial effect on the treatment or prophylaxis of UFs and can be administered orally, serving as an alternative to (or complement of) surgery or selective progesterone receptor modulators (SPRMs). Early prevention and treatment of UFs in women from high-risk groups should be our priority. Innovative forms of UF management are under intensive investigation and may be promising options in the near future. Many of them evaluated vitamin D, paricalcitol, epigallocatechin gallate (EGCG), elagolix, aromatase inhibitors (AIs), and cabergoline and deemed them to be safe and effective. The next step in such projects should be properly constructed randomized control trials (RCTs), carried out by successive phases.

Non-surgical Management of Myomas

Uterine myomas are a common condition and the leading cause of hysterectomy. Clinically, myomas can be challenging because they range from asymptomatic to causing severe, debilitating symptoms and occur in many women before childbearing is complete. Thus, women often seek uterine-conserving and nonsurgical management of their myomas. In this review the available uterine-conserving treatment options from medical management through minimally invasive procedures are discussed. To the extent of research available, the sustainability of symptom improvement and the effects on future fertility are reviewed. Future research may lead to therapies that reduce the risks of major surgery, decrease side effects, and offer primary or secondary prevention options.

Current Medical Therapy for Uterine Leiomyomas

Uterine leiomyomas are benign tumors arising from the myometrium and largely prevalent in the woman's reproductive years. The majority of women with leiomyomas either remain asymptomatic or develop symptoms gradually over time. When patients are symptomatic, the nature of their complaints is often attributable to the number, size, and/or location of their fibroids. Depending on a patient's symptomatology and reproductive plans, treatment options include expectant management, medical management (hormonal and non-hormonal), or surgical management (myomectomy or hysterectomy).

Estrogen Receptors and Signaling in Fibroids: Role in Pathobiology and Therapeutic Implications

Uterine fibroids are the most common gynecologic tumors with a significant medical and financial burden. Several genetic, hormonal, and biological factors have been shown to contribute to the development and growth of fibroid tumors. Of these factors, estrogen is particularly critical since fibroids are considered estrogen dependent because no prepubertal cases have been described in the literature and tumors tend to regress after menopause. Understanding the role of estrogen in fibroids is not only important for understanding the pathobiology of fibroids but also for the development of successful therapeutics. In this review, we discuss the types and structure of estrogen receptors (nuclear and membrane bound, including α and β receptors and G protein-coupled estrogen receptor 1 GPER1). Estrogen-signaling pathways in fibroids include genomic (direct and indirect) and nongenomic including Ras-Raf-MEK (MAPK/Erk Kinase)-mitogen-activated protein kinase (MAPK) and phosphatidylinositide 3-kinase (PI3K)-phosphatidylinositol-3,4,5-trisphosphate (PIP3)-Akt (Protein kinase B)-mammalian target of rapamycin (mTOR) pathways; shortly Ras-Raf-MEK-MAPK and PI3K-PIP3-Akt-mTOR pathways. Several aberrations in estrogen receptors and signaling pathways are implicated in fibroid pathobiology. Current therapeutic and research agents targeting ERs/signaling include gonadotropin-releasing hormone (GnRH) agonists, GnRH antagonists, aromatase inhibitors, selective ER modulators, gene therapy, and others. Future research can identify potential targets for the development of novel treatments. In particular, epigenomics of estrogen activity and individualized (precision) medicine appear to be attractive areas for future research.

Uterine fibroids

Uterine fibroids (also known as leiomyomas or myomas) are common clonal neoplasms of the uterus. Fibroids have both smooth muscle and fibroblast components, in addition to a substantial amount of fibrous extracellular matrix, which all contribute to the pathogenetic process. Fibroids are extremely heterogeneous in their pathophysiology, size, location and clinical symptomatology. They are also a part of a range of disease in which some variants have facets of malignant behaviour but overall are benign. Risk for fibroids is associated with race; black women have a higher risk of developing fibroids earlier in life than their white counterparts and also develop more-severe forms of the disease. Clinically, fibroids account for one-third to half of all hysterectomies and are associated with substantial morbidity and health care costs for women of reproductive age. Indeed, current treatments are primarily surgical and interventional; approximately three-quarters of all fibroid treatments are hysterectomies. However, clinical innovations are emerging in the use of progesterone receptor modulators as a medical therapy. New information is rapidly accumulating about the genetic subgroups that lead to fibroid formation, which might aid further understanding of the clinical heterogeneity of this disease and lead to individualized treatments. This information is a crucial development given the current lack of high-quality evidence on which to base therapeutic decisions.

Overview of latest evidence on uterine fibroids

Uterine fibroids are the most common type of benign gynecologic mass, and are present in up to 80 percent of women. Research exploring risk factors for fibroids presents conflicting or inconclusive findings. Symptoms for up to 50 percent of women experiencing fibroids include heavy menstrual bleeding, pelvic pressure or pain and gastrointestinal and genitourinary changes. Diagnosis is made by history and symptoms, physical examination and imaging. Several treatment options are available, and are based on symptoms, preferences and reproductive plans. Given the high prevalence of fibroids and the potential for women's health implications, it is essential that clinicians are aware of the latest evidence regarding fibroids to provide the highest quality of care for women whose health is affected by this condition.

Potential causes of subfertility in patients with intramural fibroids

BACKGROUND

Intramural leiomyomas have been long debated as a potential cause of infertility and pregnancy loss.

FINDINGS

Previous research has linked intramural fibroids to defective implantation, as well as to abnormal peristaltic events of the uterine smooth muscle. Previous reports describe the effects of intramural fibroids on normal human fertility and early pregnancy loss, specifically in regards to implantation failure.

CONCLUSION

A thorough understanding of prior research may direct new research focus, leading to better understanding of leiomyoma-associated infertility.

Epidemiological and genetic clues for molecular mechanisms involved in uterine leiomyoma development and growth

BACKGROUND

Uterine leiomyomas (fibroids) are highly prevalent benign smooth muscle tumors of the uterus. In the USA, the lifetime risk for women developing uterine leiomyomas is estimated as up to 75%. Except for hysterectomy, most therapies or treatments often provide only partial or temporary relief and are not successful in every patient. There is a clear racial disparity in the disease; African-American women are estimated to be three times more likely to develop uterine leiomyomas and generally develop more severe symptoms. There is also familial clustering between first-degree relatives and twins, and multiple inherited syndromes in which fibroid development occurs. Leiomyomas have been described as clonal and hormonally regulated, but despite the healthcare burden imposed by the disease, the etiology of uterine leiomyomas remains largely unknown. The mechanisms involved in their growth are also essentially unknown, which has contributed to the slow progress in development of effective treatment options.

METHODS

A comprehensive PubMed search for and critical assessment of articles related to the epidemiological, biological and genetic clues for uterine leiomyoma development was performed. The individual functions of some of the best candidate genes are explained to provide more insight into their biological function and to interconnect and organize genes and pathways in one overarching figure that represents the current state of knowledge about uterine leiomyoma development and growth.

RESULTS

In this review, the widely recognized roles of estrogen and progesterone in uterine leiomyoma pathobiology on the basis of clinical and experimental data are presented. This is followed by fundamental aspects and concepts including the possible cellular origin of uterine fibroids. The central themes in the subsequent parts are cytogenetic aberrations in leiomyomas and the racial/ethnic disparities in uterine fibroid biology. Then, the attributes of various in vitro and in vivo, human syndrome, rodent xenograft, naturally mutant, and genetically modified models used to study possible molecular mechanisms of leiomyoma development and growth are described. Particular emphasis is placed on known links to fibrosis, hypertrophy, and hyperplasia and genes that are potentially important in these processes.

CONCLUSIONS

Menstrual cycle-related injury and repair and coinciding hormonal cycling appears to affect myometrial stem cells that, at a certain stage of fibroid development, often obtain cytogenetic aberrations and mutations of Mediator complex subunit 12 (MED12). Mammalian target of rapamycin (mTOR), a master regulator of proliferation, is activated in many of these tumors, possibly by mechanisms that are similar to some human fibrosis syndromes and/or by mutation of upstream tumor suppressor genes. Animal models of the disease support some of these dysregulated pathways in fibroid etiology or pathogenesis, but none are definitive. All of this suggests that there are likely several key mechanisms involved in the disease that, in addition to increasing the complexity of uterine fibroid pathobiology, offer possible approaches for patient-specific therapies. A final model that incorporates many of these reported mechanisms is presented with a discussion of their implications for leiomyoma clinical practice.

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.

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.