Constitutive activation of Beta-catenin in uterine stroma and smooth muscle leads to the development of mesenchymal tumors in mice

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.

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.

Transcriptome and DNA methylome analyses reveal underlying mechanisms for the racial disparity in uterine fibroids

Uterine fibroids (leiomyomas) affect Black women disproportionately compared with women of other races and ethnicities in terms of prevalence, incidence, and severity of symptoms. The causes of this racial disparity are essentially unknown. We hypothesized that myometria of Black women are more susceptible to developing fibroids, and we examined the transcriptomic and DNA methylation profiles of myometria and fibroids from Black and White women for comparison. Myometrial samples cluster by race in both their transcriptome and DNA methylation profiles, whereas fibroid samples only cluster by race in the latter. More differentially expressed genes (DEGs) were detected in the Black and White myometrial sample comparison than in the fibroid comparison. Leiomyoma gene set expression analysis identified 4 clusters of DEGs, including a cluster of 24 genes with higher expression in myometrial samples from Black women. One of the DEGs in this group, von Willibrands factor (VWF), was significantly hypomethylated in both myometrial samples from Black women and in all fibroids at 2 CpG probes that are near a putative enhancer site and that are correlated with VWF expression levels. These results suggest that the molecular basis for the disparity in fibroid disease between Black and White women could be found in the myometria before fibroid development and not in the fibroids themselves.

Single-cell sequencing reveals novel cellular heterogeneity in uterine leiomyomas

STUDY QUESTION

What are the cellular composition and single-cell transcriptomic differences between myometrium and leiomyomas as defined by single-cell RNA sequencing?

SUMMARY ANSWER

We discovered cellular heterogeneity in smooth muscle cells (SMCs), fibroblast and endothelial cell populations in both myometrium and leiomyoma tissues.

WHAT IS KNOWN ALREADY

Previous studies have shown the presence of SMCs, fibroblasts, endothelial cells and immune cells in myometrium and leiomyomas. However, there is no information on the cellular heterogeneity in these tissues and the transcriptomic differences at the single-cell level between these tissues.

STUDY DESIGN, SIZE, DURATION

We collected five leiomyoma and five myometrium samples from a total of eight patients undergoing hysterectomy. We then performed single-cell RNA sequencing to generate a cell atlas for both tissues. We utilized our single-cell sequencing data to define cell types, compare cell types by tissue type (leiomyoma versus myometrium) and determine the transcriptional changes at a single-cell resolution between leiomyomas and myometrium. Additionally, we performed MED12-variant analysis at the single-cell level to determine the genotype heterogeneity within leiomyomas.

PARTICIPANTS/MATERIALS, SETTING, METHODS

We collected five MED12-variant positive leiomyomas and five myometrium samples from a total of eight patients. We then performed single-cell RNA sequencing on freshly isolated single-cell preparations. Histopathological assessment confirmed the identity of the samples. Sanger sequencing was performed to confirm the presence of the MED12 variant in leiomyomas.

MAIN RESULTS AND ROLE OF CHANCE

Our data revealed previously unknown heterogeneity in the SMC, fibroblast cell and endothelial cell populations of myometrium and leiomyomas. We discovered the presence of two different lymphatic endothelial cell populations specific to uterine leiomyomas. We showed that both myometrium and MED12-variant leiomyomas are relatively similar in cellular composition but differ in cellular transcriptomic profiles. We found that fibroblasts influence the leiomyoma microenvironment through their interactions with endothelial cells, immune cells and SMCs. Variant analysis at the single-cell level revealed the presence of both MED12 variants as well as the wild-type MED12 allele in SMCs of leiomyomatous tissue. These results indicate genotype heterogeneity of cellular composition within leiomyomas.

LARGE SCALE DATA

The datasets are available in the NCBI Gene Expression Omnibus (GEO) using GSE162122.

LIMITATIONS, REASONS FOR CAUTION

Our study focused on MED12-variant positive leiomyomas for single-cell RNA sequencing analyses. Leiomyomas carrying other genetic rearrangements may differ in their cellular composition and transcriptomic profiles.

WIDER IMPLICATIONS FOR THE FINDINGS

Our study provides a cellular atlas for myometrium and MED12-variant positive leiomyomas as defined by single-cell RNA sequencing. Our analysis provides significant insight into the differences between myometrium and leiomyomas at the single-cell level and reveals hitherto unknown genetic heterogeneity in multiple cell types within human leiomyomas. Our results will be important for future studies into the origin and growth of human leiomyomas.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by funding from the National Institute of Child Health and Human Development (HD098580 and HD088629). The authors declare no competing interests.

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.

Unveiling the Pathogenesis of Adenomyosis through Animal Models

Background: Adenomyosis is a common gynecological disorder traditionally viewed as “elusive”. Several excellent review papers have been published fairly recently on its pathogenesis, and several theories have been proposed. However, the falsifiability, explanatory power, and predictivity of these theories are often overlooked. Since adenomyosis can occur spontaneously in rodents and many other species, the animal models may help us unveil the pathogenesis of adenomyosis. This review critically tallies experimentally induced models published so far, with a particular focus on their relevance to epidemiological findings, their possible mechanisms of action, and their explanatory and predictive power. Methods: PubMed was exhaustively searched using the phrase “adenomyosis and animal model”, “adenomyosis and experimental model”, “adenomyosis and mouse”, and “adenomyosis and rat”, and the resultant papers were retrieved, carefully read, and the resultant information distilled. All the retrieved papers were then reviewed in a narrative manner. Results: Among all published animal models of adenomyosis, the mouse model of adenomyosis induced by endometrial–myometrial interface disruption (EMID) seems to satisfy the requirements of falsifiability and has the predictive capability and also Hill’s causality criteria. Other theories only partially satisfy Hill’s criteria of causality. In particular, animal models of adenomyosis induced by hyperestrogenism, hyperprolactinemia, or long-term exposure to progestogens without much epidemiological documentation and adenomyosis is usually not the exclusive uterine pathology consequent to those induction procedures. Regardless, uterine disruption appears to be a necessary but not sufficient condition for causing adenomyosis. Conclusions: EMID is, however, unlikely the sole cause for adenomyosis. Future studies, including animal studies, are warranted to understand how and why in utero and/or prenatal exposure to elevated levels of estrogen or estrogenic compounds increases the risk of developing adenomyosis in adulthood, to elucidate whether prolactin plays any role in its pathogenesis, and to identify sufficient condition(s) that cause adenomyosis.

Uterine Fibroids (Leiomyomata) and Heavy Menstrual Bleeding

Uterine Fibroids, or leiomyomata, affect millions of women world-wide, with a high incidence of 75% within women of reproductive age. In ~30% of patients, uterine fibroids cause menorrhagia, or heavy menstrual bleeding, and more than half of the patients experience symptoms such as heavy menstrual bleeding, pelvic pain, or infertility. Treatment is symptomatic with limited options including hysterectomy as the most radical solution. The genetic foundations of uterine fibroid growth have been traced to somatic driver mutations (MED12, HMGA2, FH^−/−, and COL4A5-A6). These also lead to downstream expression of angiogenic factors including IGF-1 and IGF-2, as opposed to the VEGF-driven mechanism found in the angiogenesis of hypoxic tumors. The resulting vasculature supplying the fibroid with nutrients and oxygen is highly irregular. Of particular interest is the formation of a pseudocapsule around intramural fibroids, a unique structure within tumor angiogenesis. These aberrations in vascular architecture and network could explain the heavy menstrual bleeding observed. However, other theories have been proposed such as venous trunks, or venous lakes caused by the blocking of normal blood flow by uterine fibroids, or the increased local action of vasoactive growth factors. Here, we review and discuss the evidence for the various hypotheses proposed.

Simvastatin inhibits stem cell proliferation in human leiomyoma via TGF-β3 and Wnt/β-Catenin pathways

Uterine leiomyoma (UL) is the most common gynaecologic tumour, affecting an estimated 70 to 80% of women. Leiomyomas develop from the transformation of myometrial stem cells into leiomyoma stem (or tumour-initiating) cells. These cells undergo self-renewal and differentiation to mature cells, both are necessary for the maintenance of tumour stem cell niche and tumour growth, respectively. Wnt/β-catenin and TGF-β/SMAD pathways, both overactive in UL, promote stem cell self-renewal, crosstalk between stem and mature cells, cellular proliferation, extracellular matrix (ECM) accumulation and drive overall UL growth. Recent evidence suggests that simvastatin, an antihyperlipidemic drug, may have anti-leiomyoma properties. Herein, we investigated the effects of simvastatin on UL stem cells. We isolated leiomyoma stem cells by flow cytometry using DyeCycle Violet staining and Stro-1/CD44 surface markers. We found that simvastatin inhibits proliferation and induces apoptosis in UL stem cells. In addition, it also suppressed the expression of the stemness markers Nanog, Oct4 and Sox2. Simvastatin significantly decreased the production of the key ECM proteins, collagen 1 and fibronectin. Finally, it inhibited genes and/or proteins expression of TGF-β1, 2 and 3, SMAD2, SMAD4, Wnt4, β-Catenin, LRP6, AXIN2 and Cyclin D1 in UL stem cells, all are key drivers of the TGF-β3/SMAD2 and Wnt4/β-Catenin pathways. Thus, we have identified a novel stem cell-targeting anti-leiomyoma simvastatin effect. Further studies are needed to replicate these findings in vivo.

Reoperation rates for recurrence of fibroids after abdominal myomectomy in women with large uterus

BACKGROUND

The population of women undergoing abdominal myomectomy for symptomatic large fibroid uterus is unique. We seek to characterize the timing, risk factors as well as the presenting symptoms which led patients to undergo repeat surgery in this patient population.

METHODS AND FINDINGS

We followed 592 patients who underwent an abdominal myomectomy from March 1998 to June 2010 at St. Vincent's Catholic Medical Center and presented later during the study period with a recurrence of symptoms attributable to a reemergence of fibroids and who chose to undergo repeat surgical management. Twelve percent of patients exhibited symptoms of fibroid uterus which led to reoperation within the study period. The mean age at repeat surgery was 44.1 ± 0.6 years old (n = 69) and the mean time between operations was 7.9 ± 0.3 years. Presentation was variable but included bleeding, pain and infertility. Patients presented for surgery with a significantly smaller sized uterus than at their initial surgery. Timing between surgeries correlated with age at initial surgery and uterine size but race, number of fibroids, aggregate weight of fibroids removed, operative time or blood loss at the initial surgery did not correlate. Data is suggestive that intraperitoneal triamcinolone may reduce reoperation rates but not timing of recurrence.

CONCLUSION

These results may help in counseling patients, particularly younger women, on the risks of fibroid recurrence necessitating repeat surgery. Further research is necessary to assess if triamcinolone can alter fibroid reurrence in patients who undergo uterus sparing procedures.

Simvastatin Inhibits Wnt/β-Catenin Pathway in Uterine Leiomyoma

The Wnt/β-catenin pathway is upregulated in uterine leiomyomas, the most common benign tumors in the female reproductive tract. Simvastatin is an antihyperlipidemic drug, and previous in vitro and in vivo reports showed that it may have therapeutic effects in treating leiomyomas. The objective of this study was to examine the effects of simvastatin on the Wnt/β-catenin signaling pathway in leiomyoma. We treated primary and immortalized human leiomyoma cells with simvastatin and examined its effects using quantitative real-time polymerase chain reaction, Western blotting, and immunocytochemistry. We also examined the effects using human leiomyoma tissues from an ongoing randomized controlled trial in which women with symptomatic leiomyoma received simvastatin (40 mg) or placebo for 3 months prior to their surgery. The results of this study revealed that simvastatin significantly reduced the expression of Wnt4 and its co-receptor LRP5. After simvastatin treatment, levels of total β-catenin and its active form, nonphosphorylated β-catenin, were reduced in both cell types. Additionally, simvastatin reduced the expression of Wnt4 and total β-catenin, as well as nonphosphorylated β-catenin protein expression in response to estrogen and progesterone. Simvastatin also inhibited the expression of c-Myc, a downstream target of the Wnt/β-catenin pathway. The effect of simvastatin on nonphosphorylated-β-catenin, the key regulator of the Wnt/β-catenin pathway, was recapitulated in human leiomyoma tissue. These results suggest that simvastatin may have a beneficial effect on uterine leiomyoma through suppressing the overactive Wnt/β-catenin pathway.

Identification and characterization of the mediator kinase-dependent myometrial stem cell phosphoproteome

OBJECTIVE

To identify, in myometrial stem/progenitor cells, the presumptive cell of origin for uterine fibroids, substrates of Mediator-associated cyclin dependent kinase 8/19 (CDK8/19), which is known to be disrupted by uterine fibroid driver mutations in Mediator complex subunit 12 (MED12).

DESIGN

Experimental study.

SETTING

Academic research laboratory.

PATIENT(S)

Women undergoing hysterectomy for uterine fibroids.

INTERVENTION(S)

Stable isotopic labeling of amino acids in cell culture (SILAC) coupled with chemical inhibition of CDK8/19 and downstream quantitative phosphoproteomics and transcriptomic analyses in myometrial stem/progenitor cells.

MAIN OUTCOME MEASURE(S)

High-confidence Mediator kinase substrates identified by SILAC-based quantitative phosphoproteomics were determined using an empirical Bayes analysis and validated orthogonally by in vitro kinase assay featuring reconstituted Mediator kinase modules comprising wild-type or G44D mutant MED12 corresponding to the most frequent uterine fibroid driver mutation in MED12. Mediator kinase-regulated transcripts identified by RNA sequencing were linked to Mediator kinase substrates by computational analyses.

RESULT(S)

A total of 296 unique phosphosites in 166 proteins were significantly decreased (≥ twofold) upon CDK8/19 inhibition, including 118 phosphosites in 71 nuclear proteins representing high-confidence Mediator kinase substrates linked to RNA polymerase II transcription, RNA processing and transport, chromatin modification, cytoskeletal architecture, and DNA replication and repair. Orthogonal validation confirmed a subset of these proteins, including Cut Like Homeobox 1 (CUX1) and Forkhead Box K1 (FOXK1), to be direct targets of MED12-dependent CDK8 phosphorylation in a manner abrogated by the most common uterine fibroid driver mutation (G44D) in MED12, implicating these substrates in disease pathogenesis. Transcriptome-wide profiling of Mediator kinase-inhibited myometrial stem/progenitor cells revealed alterations in cell cycle and myogenic gene expression programs to which Mediator kinase substrates could be linked directly. Among these, CUX1 is an established transcriptional regulator of the cell cycle whose corresponding gene on chromosome 7q is the locus for a recurrent breakpoint in uterine fibroids, linking MED12 and Mediator kinase with CUX1 for the first time in uterine fibroid pathogenesis. FOXK1, a transcriptional regulator of myogenic stem cell fate, was found to be coordinately enriched along with kinase, but not core, Mediator subunits in myometrial stem/progenitor cells compared with differentiated uterine smooth muscle cells.

CONCLUSION(S)

These studies identify a new catalog of pathologically and biologically relevant Mediator kinase substrates implicated in the pathogenesis of MED12 mutation-positive uterine fibroids, and further uncover a biochemical basis to link Mediator kinase activity with CUX1 and FOXK1 in the regulation of myometrial stem/progenitor cell fate.

Wnt/β-catenin signaling pathway in uterine leiomyoma: role in tumor biology and targeting opportunities

Uterine leiomyoma is the most common tumor of the female reproductive system and originates from a single transformed myometrial smooth muscle cell. Despite the immense medical, psychosocial, and financial impact, the exact underlying mechanisms of leiomyoma pathobiology are poorly understood. Alterations of signaling pathways are thought to be instrumental in leiomyoma biology. Wnt/β-catenin pathway appears to be involved in several aspects of the genesis of leiomyomas. For example, Wnt5b is overexpressed in leiomyoma, and the Wnt/β-catenin pathway appears to mediate the role of MED12 mutations, the most common mutations in leiomyoma, in tumorigenesis. Moreover, Wnt/β-catenin pathway plays a paracrine role where estrogen/progesterone treatment of mature myometrial or leiomyoma cells leads to increased expression of Wnt11 and Wnt16, which induces proliferation of leiomyoma stem cells and tumor growth. Constitutive activation of β-catenin leads to myometrial hyperplasia and leiomyoma-like lesions in animal models. Wnt/β-catenin signaling is also closely involved in mechanotransduction and extracellular matrix regulation and relevant alterations in leiomyoma, and crosstalk is noted between Wnt/β-catenin signaling and other pathways known to regulate leiomyoma development and growth such as estrogen, progesterone, TGFβ, PI3K/Akt/mTOR, Ras/Raf/MEK/ERK, IGF, Hippo, and Notch signaling. Finally, evidence suggests that inhibition of the canonical Wnt pathway using β-catenin inhibitors inhibits leiomyoma cell proliferation. Understanding the molecular mechanisms of leiomyoma development is essential for effective treatment. The specific Wnt/β-catenin pathway molecules discussed in this review constitute compelling candidates for therapeutic targeting.

Transcriptome Analyses of Myometrium from Fibroid Patients Reveals Phenotypic Differences Compared to Non-Diseased Myometrium

Uterine fibroid tissues are often compared to their matched myometrium in an effort to understand their pathophysiology, but it is not clear whether the myometria of uterine fibroid patients represent truly non-disease control tissues. We analyzed the transcriptomes of myometrial samples from non-fibroid patients (M) and compared them with fibroid (F) and matched myometrial (MF) samples to determine whether there is a phenotypic difference between fibroid and non-fibroid myometria. Multidimensional scaling plots revealed that M samples clustered separately from both MF and F samples. A total of 1169 differentially expressed genes (DEGs) (false discovery rate < 0.05) were observed in the MF comparison with M. Overrepresented Gene Ontology terms showed a high concordance of upregulated gene sets in MF compared to M, particularly extracellular matrix and structure organization. Gene set enrichment analyses showed that the leading-edge genes from the TGFβ signaling and inflammatory response gene sets were significantly enriched in MF. Overall comparison of the three tissues by three-dimensional principal component analyses showed that M, MF, and F samples clustered separately from each other and that a total of 732 DEGs from F vs. M were not found in the F vs. MF, which are likely understudied in the pathogenesis of uterine fibroids and could be key genes for future investigation. These results suggest that the transcriptome of fibroid-associated myometrium is different from that of non-diseased myometrium and that fibroid studies should consider using both matched myometrium and non-diseased myometrium as controls.

Role of inflammation in benign gynecologic disorders: from pathogenesis to novel therapies†

Emerging evidence supports the notion that inflammation fosters the development of common benign gynecologic disorders, including uterine leiomyoma, endometriosis, and adenomyosis. Numerous cytokines, chemokines, and growth and transcription factors have indisputable roles in the establishment and maintenance of benign gynecologic disorders by initiating complex cascades that promote proliferation, angiogenesis, and lesion progression. The interaction between inflammation and benign gynecologic disorders is orchestrated by a plethora of factors, including sex steroids, genetics, epigenetics, extracellular matrix, stem cells, cardiometabolic risk factors, diet, vitamin D, and the immune system. The role of inflammation in these disorders is not limited to local pathobiology but also extends to involve clinical sequelae that range from those confined to the reproductive tract, such as infertility and gynecologic malignancies, to systemic complications such as cardiovascular disease. Enhanced understanding of the intricate mechanisms of this association will introduce us to unvisited pathophysiological perspectives and guide future diagnostic and therapeutic implications aimed at reducing the burden of these disorders. Utilization of inflammatory markers, microRNA, and molecular imaging as diagnostic adjuncts may be valuable, noninvasive techniques for prompt detection of benign gynecologic disorders. Further, use of novel as well as previously established therapeutics, such as immunomodulators, hormonal treatments, cardiometabolic medications, and cyclooxygenase-2 and NF-κB inhibitors, can target inflammatory pathways involved in their pathogenesis. In this comprehensive review, we aim to dissect the existing literature on the role of inflammation in benign gynecologic disorders, including the proposed underlying mechanisms and complex interactions, its contribution to clinical sequelae, and the clinical implications this role entails.

Uterine Stem Cells and Benign Gynecological Disorders: Role in Pathobiology and Therapeutic Implications

Stem cells in the endometrium and myometrium possess an immense regenerative potential which is necessary to maintain the menstrual cycle and support pregnancy. These cells, as well as bone marrow stem cells, have also been implicated in the development of common benign gynecological disorders including leiomyomas, endometriosis and adenomyosis. Current evidence suggests the conversion of uterine stem cells to tumor initiating stem cells in leiomyomas, endometriosis stem cells, and adenomyosis stem cells, acquiring genetic and epigenetic alterations for the progression of each benign condition. In this comprehensive review, we aim to summarize the progress that has been made to characterize the involvement of stem cells in the pathogenesis of benign gynecologic conditions which, despite their enormous burden, are not yet fully understood. We focus on the stem cell characteristics and aberrations that contribute to the development of benign gynecological disorders and the possible clinical implications of what is known so far. Lastly, we discuss the role of uterine stem cells in the setting of regenerative medicine, particularly in the treatment of Asherman syndrome.Graphical abstract.

Animal Models of Adenomyosis

Adenomyosis is a nonmalignant uterine disorder in which endometrial tissue exists within and grows into the myometrium. Animal models have generated limited insight into the still-unclear pathogenesis of adenomyosis, provided a platform for preclinical screening of many drugs and compounds with potential as therapeutics, and elucidated mechanisms underlying the pain and fertility issues that occur in many women with the disease. Spontaneous adenomyosis has been studied in nonhuman primates, primarily in the form of case reports. Adenomyosis is routinely experimentally induced in mice through methods such as neonatal tamoxifen exposure, pituitary engraftment, and human tissue xenotransplantation. Several studies have also reported hormonal or environmental toxicant exposures that give rise to murine adenomyosis, and genetically engineered models have been created that recapitulate the human-like condition, most notably involving alteration of β-catenin expression. This review describes the animal models for adenomyosis and their contributions to our understanding of the factors underpinning the development of symptoms. Animal models represent a unique opportunity for understanding the molecular basis of adenomyosis and developing efficacious treatment options for affected women. Herein, we assess their different potentials and limitations with regard to identification of new therapeutic interventions and reflect on future directions for research and drug validation.

Vitamin D as an effective treatment in human uterine leiomyomas independent of mediator complex subunit 12 mutation

OBJECTIVE

To study whether vitamin D (VitD) inhibits cell proliferation and Wnt/β-catenin and transforming growth factor-β (TGFβ) signaling pathways in uterine leiomyomas independent of mediator complex subunit 12 (MED12) mutation status.

DESIGN

Prospective study comparing leiomyoma vs. myometrial tissues and human uterine leiomyoma primary (HULP) cells treated with or without VitD and analyzed by MED12 mutation status.

SETTING

Hospital and university laboratories.

PATIENT(S)

Women with uterine leiomyoma without any treatment (n = 37).

INTERVENTION(S)

Uterine leiomyoma and myometrium samples were collected from women undergoing surgery because of symptomatic leiomyoma pathology.

MAIN OUTCOME MEASURE(S)

Analysis of Wnt/β-catenin and TGFβ pathways and proliferation by quantitative real-time polymerase chain reaction in leiomyoma and myometrial tissue as well as in VitD-treated HULP cells analyzed by Sanger sequencing.

RESULTS

Sequencing data showed that 46% of leiomyomas presented MED12 mutation, whereas no mutations were detected in adjacent myometrium. Expression of Wnt/β-catenin and TGFβ pathway genes was significantly increased in MED12-mutated leiomyomas compared to matched myometrium; no significant differences were found in wild-type (WT) leiomyomas. In HULP cells, VitD significantly decreased PCNA expression of both MED12-mutated and WT groups. VitD treatment decreased WNT4 and β-catenin expression in both groups compared to controls, with significance for WNT4 expression in MED12-mutated samples. Similarly, VitD significantly inhibited TGFβ3 expression in cells from both groups. MMP9 expression also decreased.

CONCLUSION

Despite molecular differences between MED12-mutated and WT leiomyomas, VitD inhibited Wnt/β-catenin and TGFβ pathways in HULP cells, suggesting VitD as an effective treatment to reduce proliferation and extracellular matrix formation in different molecular subtypes of uterine leiomyomas.

Non-hormonal mediators of uterine fibroid growth

PURPOSE OF REVIEW

Uterine fibroids are the most common benign neoplasms of the female reproductive tract and one of the major public health concerns. Although most women with uterine fibroids are asymptomatic, over 30% of them will present with varying symptoms. This review focuses on the role of non-hormonal mediators and pathways in uterine fibroid biology. Furthermore, it provides data regarding the most recent findings in the field of compounds, which use those non-hormonal pathways in the medical therapy of uterine fibroids.

RECENT FINDINGS

Complex signaling pathway alterations are crucial for uterine fibroid development. The topic of the pathophysiology of uterine fibroids focuses mostly on steroids and other hormones. However, other very important pathways exist, and some of them are independent of hormones. Some of the most important pathways, which are non-hormonal, but in some cases still hormone-depended, include growth factors, cytokines and inflammation, Smad proteins, wingless type/β-catenin and others.

SUMMARY

Much more is known about hormonal than about non-hormonal signaling in uterine fibroids. Growth factors, early life exposure and inflammation are key factors in uterine fibroid biology. Numerous agents depend on those pathways and may find their place in the current and future therapy of uterine fibroids.

Activation of protein kinase B by WNT4 as a regulator of uterine leiomyoma stem cell function

OBJECTIVE

To investigate the functional interaction between the Wnt/β-catenin and protein kinase B (Akt) pathways in leiomyoma stem cells (LSC).

DESIGN

Laboratory study.

SETTING

Research laboratory.

PATIENT(S)

Premenopausal women (n = 36; age range: 28 to 49 years) undergoing hysterectomy or myomectomy for leiomyoma.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Gene expression, protein phosphorylation, and cell proliferation.

RESULT(S)

Cells from human leiomyoma tissues were sorted by fluorescence-activated cell sorting (FACS) into three populations: LSC, intermediate cells (LIC), and differentiated cells (LDC) with the function of the Wnt/β-catenin and Akt signaling pathways in leiomyoma cells evaluated using real-time quantitative polymerase chain reaction and immunoblot analyses. The Wnt/β-catenin signaling pathway components were differentially expressed in each leiomyoma cell population. WNT4 was distinctly overexpressed in LIC, and its receptor FZD6 was primarily expressed in LSC. WNT4 stimulated Akt phosphorylation, activated β-catenin, and increased primary leiomyoma cell proliferation. These stimulatory effects were abolished by cotreatment with the Akt inhibitor, MK-2206. WNT4 up-regulated the expression of pro-proliferative genes, c-Myc and cyclin D1, specifically in LSC; this was also abrogated by Akt inhibition.

CONCLUSION(S)

Our data suggest that WNT4 regulates LSC proliferation via Akt-dependent β-catenin activation, representing a key step toward a better understanding of LSC regulation and potentially novel therapeutic targets.

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.

The Evolving Role of Natural Compounds in the Medical Treatment of Uterine Fibroids

Uterine fibroids (UFs) remain a significant health issue for many women, with a disproportionate impact on women of color, likely due to both genetic and environmental factors. The prevalence of UFs is estimated to be approximately 70% depending on population. UF-derived clinical symptoms include pelvic pain, excessive uterine bleeding, gastrointestinal and voiding problems, as well as impaired fertility. Nowadays numerous methods of UF treatment are available-from conservative treatment to invasive surgeries. Selecting an appropriate treatment option should be individualized and adjusted to the patient's expectations as much as possible. So far, the mainstay of treatment is surgery, but their negative impact of future fertility is clear. On the other hand, emerging new pharmaceutical options have significant adverse effects like liver function impairment, hot flashes, bone density loss, endometrial changes, and inability to attempt conception during treatment. Several natural compounds are found to help treat UFs and relieve their symptoms. In this review we summarize all the current available data about natural compounds that may be beneficial for patients with UFs, especially those who want to preserve their future fertility or have treatment while actively pursuing conception. Vitamin D, epigallocatechin gallate, berberine, curcumin, and others are being used as alternative UF treatments. Moreover, we propose the concept of using combined therapies of natural compounds on their own or combined with hormonal agents to manage UFs. There is a strong need for more human clinical trials involving these compounds before promoting widespread usage.

Activation of β-Catenin Signaling and its Crosstalk With Estrogen and Histone Deacetylases in Human Uterine Fibroids

CONTEXT

Uterine fibroids (UF) are the most common benign tumor of the myometrium (MM) in women of reproductive age. However, the mechanism underlying the pathogenesis of UF is largely unknown.

OBJECTIVE

To explore the link between nuclear β-catenin and UF phenotype and β-catenin crosstalk with estrogen and histone deacetylases (HDACs).

DESIGN

Protein/RNA levels of β-catenin (CTNNB1 gene), its responsive markers cyclin D1 and c-Myc, androgen receptor (AR), p27, and class-I HDACs were measured in matched UF/MM tissues or cell populations. The effects of chemical inhibition/activation and genetic knockdown of CTNNB1 on UF phenotype were measured. The anti-UF effect of 2 HDAC inhibitors was evaluated.

MAIN OUTCOME MEASURE

β-catenin nuclear translocation in response to β-catenin inhibition/activation, estrogen, and HDAC inhibitors in UF cells.

RESULTS

UF tissues/cells showed significantly higher expression of nuclear β-catenin, cyclin D1, c-Myc, and HDACs 1, 2, 3, and 8 than MM. Estradiol induced β-catenin nuclear translocation and consequently its responsive genes in both MM and UF cells, while an estrogen receptor antagonist reversed this induction effect. Treatment with β-catenin or HDAC inhibitors led to dose-dependent growth inhibition, while Wnt3a treatment increased proliferation compared with control. Chemical inhibition of β-catenin decreased cyclin D1 and c-Myc expression levels, while β-catenin activation increased expression of the same markers. Genetic knockdown of CTNNB1 resulted in a marked decrease in β-catenin, cyclin D1, c-Myc, and AR expression. Treatment of UF cells with HDAC inhibitors decreased nuclear β-catenin, cyclin D1, and c-Myc expression. Moreover, HDAC inhibitors induced apoptosis of UF cells and cell cycle arrest.

CONCLUSION

β-catenin nuclear translocation contributes to UF phenotype, and β-catenin signaling is modulated by estradiol and HDAC activity.

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.

NAV3, a Tumor Suppressor Gene, Is Decreased in Uterine Leiomyoma Tissue and Cells

NAV 3 is a tumor suppressor of unknown function in leiomyomas. The objective of this study is to assess NAV3 expression and its potential role in human uterine leiomyomas. NAV3 protein expression was examined in patient leiomyoma and patient-matched myometrial tissue samples by Western blot and immunohistochemistry. NAV3 mRNA and protein expression was assessed in leuprolide acetate- and cetrorelix-treated cell line leiomyoma samples. RNAseq analysis of placebo-treated leiomyoma compared with myometrium demonstrated the presence of transcripts encoding for several neuronal proteins. For NAV3, RNA sequence analysis demonstrated decreased expression in leiomyoma as compared with myometrium (0.86 ± 0.03 fold). Presence of NAV3 mRNA was also decreased in leiomyoma surgical samples (0.43 fold ± 0.05, p = 0.026) compared with patient-matched myometrium. Confirmatory qRT-PCR results on immortalized leiomyoma and myometrial cell lines similarly demonstrated a decrease in expression of NAV3 in leiomyomas (0.28 ± 0.02, p = 0.00075). Immunohistochemical analysis demonstrated a significant decrease in NAV 3 protein in leiomyomas (H-score 154.7 ± 6.2) as compared with myometrium (H-score; 312.5 ± 14.7, p < 0.0001). Leuprolide acetate-treated leiomyoma cells demonstrated an increase in NAV 3 mRNA expression (1.53 ± 0.13, p < 0.0001). Similarly, Western blot analysis on leuprolide-treated leiomyoma cells showed a non-significant increase in NAV 3 protein expression (1.26 ± 0.09, p = 0.063). NAV 3, a tumor suppressor in numerous cancers, is decreased in leiomyoma cells and tissue compared with myometrium, and increased by GnRH analog treatment, suggesting that NAV3 may mediate steroid hormone-independent leiomyoma regulation by GnRH analogs.

Biomarkers in abnormal uterine bleeding†

Abnormal uterine bleeding (AUB) is an extremely common problem and represents a clinical area of unmet need. It has clinical implications and a high cost for the healthcare system. The PALM-COEIN acronym proposed by FIGO may be used as a foundation of care; it improves the understanding of the causes of AUB, and in doing so facilitates effective history taking, examination, investigations, and management. Heavy menstrual bleeding, a subset of AUB, is a subjective diagnosis and should be managed in the context of improving the woman's quality of life. Available evidence suggests that there is poor satisfaction with standard treatment options often resulting in women opting for major surgery such as hysterectomy. Such women would benefit from a tailored approach, both for diagnosis and treatment, highlighting the deficiency of biomarkers in this area. This article focuses on the causes of AUB as per the PALM-COEIN acronym, the researched biomarkers in this area, and the potential pathogenetic mechanisms. In the future, these approaches may improve our understanding of AUB, thereby enabling us to direct women to most suitable current treatments and tailor investigative and treatment strategies to ensure best outcomes, in keeping with the principles of personalized or precision medicine.

Uterine polyps, adenomyosis, leiomyomas, and endometrial receptivity

Endometrial polyps, adenomyosis, and leiomyomas are commonly encountered abnormalities frequently found in both fertile women and those with infertility. The clinician is frequently challenged to determine which of these entities, when found, is likely to impair fertility, and which are "innocent bystanders" unrelated to the problem at hand. Although removing an endometrial polyp may be seen as a relatively benign and safe intervention, myomectomy, and in particular adenomyomectomy, can be substantive surgical procedures, associated with their own potential for disrupting fertility. One of the mechanisms thought to be involved when these entities are contributing to infertility is an adverse impact on endometrial receptivity. Indeed polyps, adenomyosis, and leiomyomas have all been associated with an increased likelihood of abnormal endometrial molecular expressions thought to impair implantation and early embryo development. This review is designed to examine the relationship of these common entities to endometrial receptivity and to identify evidence gaps that should be considered when strategizing research initiatives. It is apparent that we have the tools necessary to fill these gaps, but it will be necessary to approach the issue in a strategic and coordinated fashion. It is likely that we will have to recognize the limitations of imaging alone and look to the evidence-based addition of molecular analysis to provide the individualized phenotyping of disease necessary for patient-specific treatment decisions.

Natural Antioxidant Resveratrol Suppresses Uterine Fibroid Cell Growth and Extracellular Matrix Formation In Vitro and In Vivo

Resveratrol (RSV) is a polyphenolic phytoalexin found in peanuts, grapes, and other plants. Uterine fibroids (UF) are benign growths that are enriched in extracellular matrix (ECM) proteins. In this study, we aimed to investigate the effects of RSV on UF using in vivo and in vitro approaches. In mouse xenograft models, tumors were implanted through the subcutaneous injection of Eker rat-derived uterine leiomyoma cells transfected with luciferase (ELT-3-LUC) in five-week-old female nude (Foxn1^nu) mice. When the tumors reached a size of 50-100 mm³, the mice were randomly assigned to intraperitoneal treatment with RSV (10 mg·kg^-1) or vehicle control (dimethyl sulfoxide). Tumor tissues were assayed using an immunohistochemistry analysis. We also used primary human leiomyoma cells as in vitro models. Cell viability was determined using the sodium bicarbonate and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The protein expression was assayed using Western blot analysis. The messenger ribonucleic acid (mRNA) expression was assayed using quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Cell apoptosis was assayed using Annexin V-fluorescein isothiocyanate (FITC) and propidium iodide (PI) and Hoechst 33342 staining. RSV significantly suppressed tumor growth in vivo and decreased the proportion of cells showing expression of proliferating cell nuclear antigen (PCNA) and α-smooth muscle actin (α-SMA). In addition, RSV decreased the protein expression of PCNA, fibronectin, and upregulated the ratio of Bax (Bcl-2-associated X) and Bcl-2 (B-cell lymphoma/leukemia 2) in vivo. Furthermore, RSV reduced leiomyoma cell viability, and decreased the mRNA levels of fibronectin and the protein expression of collagen type 1 (COL1A1) and α-SMA (ECM protein marker), as well as reducing the levels of β-catenin protein. RSV induced apoptosis and cell cycle arrest at sub-G1 phase. Our findings indicated the inhibitory effects of RSV on the ELT-3-LUC xenograft model and indicated that RSV reduced ECM-related protein expression in primary human leiomyoma cells, demonstrating its potential as an anti-fibrotic therapy for UF.

Uterine stem cells: from basic research to advanced cell therapies

BACKGROUND

Stem cell research in the endometrium and myometrium from animal models and humans has led to the identification of endometrial/myometrial stem cells and their niches. This basic knowledge is beginning to be translated to clinical use for incurable uterine pathologies. Additionally, the implication of bone marrow-derived stem cells (BMDSCs) in uterine physiology has opened the field for the exploration of an exogenous and autologous source of stem cells.

OBJECTIVE AND RATIONALE

In this review, we outline the progress of endometrial and myometrial stem/progenitor cells in both human and mouse models from their characterization to their clinical application, indicating roles in Asherman syndrome, atrophic endometrium and tissue engineering, among others.

SEARCH METHODS

A comprehensive search of PubMed and Google Scholar up to December 2017 was conducted to identify peer-reviewed literature related to the contribution of bone marrow, endometrial and myometrial stem cells to potential physiological regeneration as well as their implications in pathologies of the human uterus.

OUTCOMES

The discovery and main characteristics of stem cells in the murine and human endometrium and myometrium are presented together with the relevance of their niches and cross-regulation. The current state of advanced stem cell therapy using BMDSCs in the treatment of Asherman syndrome and atrophic endometrium is analyzed. In the myometrium, the understanding of genetic and epigenetic defects that result in the development of tumor-initiating cells in the myometrial stem niche and thus contribute to the growth of uterine leiomyoma is also presented. Finally, recent advances in tissue engineering based on the creation of novel three-dimensional scaffolds or decellularisation open up new perspectives for the field of uterine transplantation.

WIDER IMPLICATIONS

More than a decade after their discovery, the knowledge of uterine stem cells and their niches is crystalising into novel therapeutic approaches aiming to treat with cells those conditions that cannot be cured with drugs, particularly the currently incurable uterine pathologies. Additional work and improvements are needed, but the basis has been formed for this therapeutic application of uterine cells.

Oestrogen fuels the growth of endometrial hyperplastic lesions initiated by overactive Wnt/β-catenin signalling

Unopposed oestrogen is responsible for approximately 80% of all the endometrial cancers. The relationship between unopposed oestrogen and endometrial cancer was indicated by the increase in the number of endometrial cancer cases due to the widespread use of oestrogen replacement therapy. Approximately 30% of the endometrial cancer patients have mutations in the Wnt signalling pathway. How the unbalanced ratios of ovarian hormones and the mutations in Wnt signalling pathway interact to cause endometrial cancer is currently unclear. To study this, we have developed a uterine epithelial cell-specific inducible cre mouse model and used 3D in vitro culture of human endometrial cancer cell lines. We showed that activating mutations in the Wnt signalling pathway for a prolonged period leads to endometrial hyperplasia but not endometrial cancer. Interestingly, unopposed oestrogen and activating mutations in Wnt signalling together drive the progression of endometrial hyperplasia to endometrial cancer. We have provided evidence that progesterone can be used as a targeted therapy against endometrial cancer cases presented with the activating mutations in Wnt signalling pathway.

Secreted frizzled-related protein 2 (SFRP2) expression promotes lesion proliferation via canonical WNT signaling and indicates lesion borders in extraovarian endometriosis

STUDY QUESTION

What is the role of SFRP2 in endometriosis?

SUMMARY ANSWER

SFRP2 acts as a canonical WNT/CTNNB1 signaling agonist in endometriosis, regulating endometriosis lesion growth and indicating endometriosis lesion borders together with CTNNB1 (also known as beta catenin).

WHAT IS KNOWN ALREADY

Endometriosis is a common, chronic disease that affects women of reproductive age, causing pain and infertility, and has significant economic impact on national health systems. Despite extensive research, the pathogenesis of endometriosis is poorly understood, and targeted medical treatments are lacking. WNT signaling is dysregulated in various human diseases, but its role in extraovarian endometriosis has not been fully elucidated.

STUDY DESIGN, SIZE, DURATION

We evaluated the significance of WNT signaling, and especially secreted frizzled-related protein 2 (SFRP2), in extraovarian endometriosis, including peritoneal and deep lesions. The study design was based on a cohort of clinical samples collected by laparoscopy or curettage and questionnaire data from healthy controls and endometriosis patients.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Global gene expression analysis in human endometrium (n = 104) and endometriosis (n = 177) specimens from 47 healthy controls and 103 endometriosis patients was followed by bioinformatics and supportive qPCR analyses. Immunohistochemistry, Western blotting, primary cell culture and siRNA knockdown approaches were used to validate the findings.

MAIN RESULTS AND THE ROLE OF CHANCE

Among the 220 WNT signaling and CTNNB1 target genes analysed, 184 genes showed differential expression in extraovarian endometriosis (P < 0.05) compared with endometrium tissue, including SFRP2 and CTNNB1. Menstrual cycle-dependent regulation of WNT genes observed in the endometrium was lost in endometriosis lesions, as shown by hierarchical clustering. Immunohistochemical analysis indicated that SFRP2 and CTNNB1 are novel endometriosis lesion border markers, complementing immunostaining for the known marker CD10 (also known as MME). SFRP2 and CTNNB1 localized similarly in both the epithelium and stroma of extraovarian endometriosis tissue, and interestingly, both also indicated an additional distant lesion border, suggesting that WNT signaling is altered in the endometriosis stroma beyond the primary border indicated by the known marker CD10. SFRP2 expression was positively associated with pain symptoms experienced by patients (P < 0.05), and functional loss of SFRP2 in extraovarian endometriosis primary cell cultures resulted in decreased cell proliferation (P < 0.05) associated with reduced CTNNB1 protein expression (P = 0.05).

LIMITATIONS REASONS FOR CAUTION

SFRP2 and CTNNB1 improved extraovarian endometriosis lesion border detection in a relatively small cohort (n = 20), although larger studies with different endometriosis subtypes in variable cycle phases and under hormonal medication are required.

WIDER IMPLICATIONS OF THE FINDINGS

The highly expressed SFRP2 and CTNNB1 improve endometriosis lesion border detection, which can have clinical implications for better visualization of endometriosis lesions over CD10. Furthermore, SFRP2 acts as a canonical WNT/CTNNB1 signaling agonist in endometriosis and positively regulates endometriosis lesion growth, suggesting that the WNT pathway may be an important therapeutic target for endometriosis.

STUDY FUNDING/COMPETING INTEREST(S)

This study was funded by the Academy of Finland and by Tekes: Finnish Funding Agency for Innovation. The authors have no conflict of interest to declare.

Upregulation of miR‑33b promotes endometriosis via inhibition of Wnt/β‑catenin signaling and ZEB1 expression

The present study aimed to investigate the role and mechanisms of microRNA (miR)‑33b in endometriosis (Ems). Reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR), MTT assays, flow cytometry, caspase‑3/9 activity assays and western blotting were performed in the present study. Initially, miR‑33b expression in an Ems rat model was investigated by RT‑qPCR and was demonstrated to be upregulated in Ems tissue samples of rats compared with the control group. In addition, miR‑33b upregulation inhibited cell growth and enhanced apoptosis in an Ems model (primary cell cultures) compared with the control group. In addition, miR‑33b up‑regulation reduced Wnt/β‑catenin signaling pathway and suppressed zinc finger E‑box‑binding homeobox 1 (ZEB1) protein expression in the in vitro Ems model (primary cell cultures) compared with the control group. Furthermore, small interfering‑ZEB1 ameliorated the effects of miR‑33b downregulation on Ems cell growth in the in vitro Ems model. Additionally, a Wnt agonist reduced the effects of miR‑33b upregulation on Ems cell growth in the in vitro Ems model. In conclusion, the present study demonstrated that upregulation of miR‑33b may promote Ems through Wnt/β‑catenin by ZEB1 expression.

Pathological cardiac remodeling occurs early in CKD mice from unilateral urinary obstruction, and is attenuated by Enalapril

Cardiovascular disease constitutes the leading cause of mortality in patients with chronic kidney disease (CKD) and end-stage renal disease. Despite increasing recognition of a close interplay between kidney dysfunction and cardiovascular disease, termed cardiorenal syndrome (CRS), the underlying mechanisms of CRS remain poorly understood. Here we report the development of pathological cardiac hypertrophy and fibrosis in early stage non-uremic CKD. Moderate kidney failure was induced three weeks after unilateral urinary obstruction (UUO) in mice. We observed pathological cardiac hypertrophy and increased fibrosis in UUO-induced CKD (UUO/CKD) animals. Further analysis indicated that this cardiac fibrosis was associated with increased expression of transforming growth factor β (TGF-β) along with significant upregulation of Smad 2/3 signaling in the heart. Moreover early treatment of UUO/CKD animals with an angiotensin-converting-enzyme inhibitor (ACE I), Enalapril, significantly attenuated cardiac fibrosis. Enalapril antagonized activation of the TGF-β signaling pathway in the UUO/CKD heart. In summary our study demonstrates the presence of pathological cardiac hypertrophy and fibrosis in mice early in UUO-induced CKD, in association with early activation of the TGF-β/Smad signaling pathway. We also demonstrate the beneficial effect of ACE I in alleviating this early fibrogenic process in the heart in UUO/CKD animals.

An update of Wnt signalling in endometrial cancer and its potential as a therapeutic target

Endometrial cancer is the most common gynaecological malignancy in developed nations, and its prevalence is rising as women defer or decide not to have children and as obesity rises, both key risk factors. Despite this, treatment options remain limited, particularly for advanced or refractory disease. New genomic analyses have revealed distinct mutational profiles with therapeutic and prognostic potential. Wnt signalling, which is pivotal in embryogenesis, healing and homeostasis, is of importance in the endometrium and has been linked to carcinogenesis. This review aims to update and discuss the current evidence for the role of β-catenin dependent and independent Wnt signalling, including the ROR receptors in the endometrium and its potential as a therapeutic target, in light of recent trials of Wnt-targeted therapy in multiple tumour types.

Stromal Clues in Endometrial Carcinoma: Loss of Expression of β-Catenin, Epithelial-Mesenchymal Transition Regulators, and Estrogen-Progesterone Receptor

Supplemental Digital Content is available in the text.

Epithelial-stroma interactions in the endometrium are known to be responsible for physiological functions and emergence of several pathologic lesions. Periglandular stromal cells act on endometrial cells in a paracrine manner through sex hormones. In this study, we immunohistochemically evaluated the expression of epithelial-mesenchymal transition regulators (SNAIL/SLUG, TWIST, ZEB1), adhesion molecules (β-catenin and E-cadhenin), estrogen (ER)-progesterone (PR) receptor and their correlation with each other in 30 benign, 148 hyperplastic (EH), and 101 endometrioid-type endometrial carcinoma (EC) endometria. In the epithelial component, loss of expression in E-cadherin, ER and PR, and overexpression of TWIST and ZEB1 were significantly higher in EC than in EH (P<0.01). In the periglandular stromal component, β-catenin and SNAIL/SLUG expression were significantly higher in normal endometrium and simple without atypical EH compared with complex atypical EH and EC (P<0.01). In addition, periglandular stromal TWIST expression was significantly higher in EH group compared with EC (P<0.05). There was significantly negative correlation between β-catenin and ER, TWIST and ER, and TWIST and PR in hyperplastic and carcinomatous glandular epithelium, whereas there was a significantly positive correlation between β-catenin and SNAIL-SLUG, β-catenin and TWIST, β-catenin and ER, β-catenin and PR, SNAIL-SLUG and ER, SNAIL-SLUG and PR, TWIST and ER, TWIST and PR, in periglandular/cancer-associated stromal cells (P<0.01). In conclusion, the pattern of positive and negative correlations in the expression of epithelial-mesenchymal transition regulators (SNAIL-SLUG and TWIST), sex hormone receptors (ER and PR), and β-catenin between ECs and hyperplasia, as well as between epithelium and stroma herein, is suggestive of a significant role for these proteins and their underlying molecular processes in the development of endometrial carcinomas.

Role of Transforming Growth Factor β in Uterine Fibroid Biology

Uterine fibroids (UFs) are benign tumors of the female genital tract made of the smooth muscle of the uterus. UF growth depends mostly on the influence of the steroid hormones and selected growth factors. Transforming growth factor β (TGF-βs) is a polypeptide that consists of three isoforms: TGF-β1, TGF-β2, and TGF-β3. At present, TGF-β is considered to be one of the key factors in the pathophysiology of UFs. It plays a major role in cellular migration within the tumor, stimulates tumor growth, and enhances tumor metabolism. As a consequence of various dependencies, the synthesis and release of TGF-β in a UF tumor is increased, which results in excessive extracellular matrix production and storage. High concentrations or overexpression of TGF-β mediators may be responsible for clinically symptomatic UFs. The aim of this review was to check the available evidence for the influence of the TGF-β family on UF biology. We conducted their search in PubMed of the National Library of Medicine with the use of the following selected keywords: “uterine fibroid”, “leiomyoma”, and “transforming growth factor β”. After reviewing the titles and abstracts, more than 115 full articles were evaluated. We focused on the TGF-β-related molecular aspects and their influence on the most common symptoms that are associated with UFs. Also, we described how the available data might implicate the current medical management of UFs.

Extracellular matrix (ECM) activates β-catenin signaling in uterine fibroids

Recent studies showed that genetic aberrations in the MED12 gene, probably through the canonical WNT/β-catenin pathway, lead to the pathogenesis of uterine fibroids. However, a comprehensive analysis of the WNT pathway in MED12-mutated and MED12-wild-type fibroids has not been performed. The objective of this study was to determine the status of the WNT pathway in human fibroids. We performed Sanger sequencing to define the MED12 mutational status of fibroids and normal myometrium samples. qPCR arrays were carried out to determine the status of the WNT signaling pathway in MED12-mutated and MED12-wild-type fibroids. Liquid chromatography-mass spectrometry (LC-MS), Western blotting and immunohistochemistry were used to monitor the expression of β-catenin. We showed that β-catenin expression was increased in fibroids compared to the adjacent myometrium samples. However, β-catenin expression showed no correlation with MED12 mutation status. Of all the WNT signaling components, WNT inhibitors showed the greatest differences in expression between fibroids and controls. WIF1, a WNT inhibitor, was identified as the most significantly upregulated gene in fibroids. We cultured primary fibroid cells on hydrogels of known stiffness to decipher the influence of biomechanical cues on β-catenin expression and revealed increased levels of β-catenin when cells were cultured on a stiffer surface. In conclusion, our data showed that β-catenin expression in fibroids occurs independently of MED12 mutations. Biomechanical changes upregulate β-catenin expression in fibroids, providing an attractive avenue for developing new treatments for this disease.

A Role for Progesterone-Regulated sFRP4 Expression in Uterine Leiomyomas

CONTEXT

Despite progesterone's key role in uterine smooth muscle tumorigenesis, the mechanisms by which it promotes the growth of uterine leiomyomas remain poorly understood.

OBJECTIVE

The aim of this study was to identify gene products mediating the effects of progesterone in uterine leiomyomas.

DESIGN

Gene expression profiling was used to identify putative progesterone-regulated genes differentially expressed in uterine leiomyomas, which were then studied in vitro.

METHODS

Gene expression was comprehensively profiled with the Illumina WG BeadChip (version 2.6) and analyzed with a bioinformatic algorithm that integrates known protein-protein interactions. Genomic binding sites for progesterone receptor (PR) were interrogated by chromatin immunoprecipitation-quantitative polymerase chain reaction (ChIP-qPCR). Small interfering RNA was used to study gene function in primary cell lines.

RESULTS

Our analyses identified secreted Frizzled-related protein 4 (sFRP4) as a key gene product functionally linked to PR activation whose expression was 2.6 times higher in leiomyomas than myometrium (n = 26, P < 0.01) and 2.5 times higher during the proliferative phase of the menstrual cycle (n = 26, P < 0.01). Direct binding between PR and sFRP4 promoter was observed by ChIP-qPCR. Robust overexpression of sFRP4 was also observed in primary cultures derived from leiomyoma. Progesterone preferentially inhibited sFRP4 expression and secretion in leiomyoma cultures in a dose-dependent manner sensitized by estradiol. Knockdown of sFRP4 inhibited proliferation and apoptosis in primary cultures of both myometrium and leiomyoma.

CONCLUSIONS

Overexpression of sFRP4 is a robust, progesterone-regulated feature of leiomyomas that increases smooth muscle proliferation. More work is needed to elucidate how progesterone's ability to modulate sFRP4 expression contributes to uterine smooth muscle tumorigenesis.

Developmental Contribution of Wnt-signal-responsive Cells to Mouse Reproductive Tract Formation

In mammals, the müllerian duct (MD) is an embryonic tubular structure that gives rise to the female reproductive tract (FRT). The MD originates from the coelomic epithelium (CoE) and takes on a rostral to caudal shape to establish the primary structure of the FRT under the regulation of morphogenetic signals. During these developmental processes, the MD and its derivatives require proper regulation of the Wnt-signaling-pathway. Here, to investigate the developmental contribution of FRT primordia under the influence of the Wnt-signaling, genetic lineage tracing was carried out using TopCreER/Rosa-LacZ mice to follow the fate of Wnt-signal-responsive cells during reproductive tract formation. TopCreER-marked-LacZ+ cells, arising from the Wnt-signal-responsive progenitors in CoE, give rise to spatially restricted MD and the uterine luminal epithelium. Similarly, the progeny from LacZ+ mesenchymal cells surrounding the MD contribute to both the uterine smooth muscle and stroma. Furthermore, in males, the Wnt-signal-responsive MD mesenchyme develops into the epididymis. These results show, for the first time, evidence of the sequential involvement of reproductive tract progenitors under the influence of Wnt-signal throughout the developmental term. This study provides a precise outline for assessing the lineage relation between the reproductive tract and the cell fate of its primordia in a temporally regulated manner.

Literature Review on the Role of Uterine Fibroids in Endometrial Function

Uterine fibroids are benign uterine smooth muscle tumors that are present in up to 8 out of 10 women by the age of 50. Many of these women experience symptoms such as heavy and irregular menstrual bleeding, early pregnancy loss, and infertility. Traditionally believed to be inert masses, fibroids are now known to influence endometrial function at the molecular level. We present a comprehensive review of published studies on the effect of uterine fibroids on endometrial function. Our goal was to explore the current knowledge about how uterine fibroids interact with the endometrium and how these interactions influence clinical symptoms. Our review shows that submucosal fibroids produce a blunted decidualization response with decreased release of cytokines critical for implantation such as leukocyte inhibitory factor and cell adhesion molecules. Furthermore, fibroids alter the expression of genes relevant for implantation, such as bone morphogenetic protein receptor type II, glycodelin, among others. With regard to heavy menstrual bleeding, fibroids significantly alter the production of vasoconstrictors in the endometrium, leading to increased menstrual blood loss. Fibroids also increase the production of angiogenic factors such as basic fibroblast growth factor and reduce the production of coagulation factors resulting in heavy menses. Understanding the crosstalk between uterine fibroids and the endometrium will provide key insights into implantation and menstrual biology and drive the development of new and innovative therapeutic options for the management of symptoms in women with uterine fibroids.

Deletion of β1-integrin in collecting duct principal cells leads to tubular injury and renal medullary fibrosis

The renal collecting duct (CD) contains two major cell types, intercalated (ICs) and principal cells (PCs). A previous report showed that deletion of β1-integrin in the entire renal CD causes defective CD morphogenesis resulting in kidney dysfunction. However, subsequent deletion of β1-integrin specifically in ICs and PCs, respectively, did not cause any morphological defects in the CDs. The discrepancy between these studies prompts us to reinvestigate the role of β1-integrin in CD cells, specifically in the PCs. We conditionally deleted β1-integrin in mouse CD PCs using a specific aquaporin-2 (AQP2) promoter Cre-LoxP system. The resulting mutant mice, β-1^f/fAQP2-Cre+, had lower body weight, failed to thrive, and died around 8-12 wk. Their CD tubules were dilated, and some of them contained cellular debris. Increased apoptosis and proliferation of PCs were observed in the dilated CDs. Trichrome staining and electron microscopy revealed the presence of peritubular and interstitial fibrosis that is associated with increased production of extracellular matrix proteins including collagen type IV and fibronectin, as detected by immunoblotting. Further analysis revealed a significantly increased expression of transforming growth factor-β (TGF-β)-induced protein, fibronectin, and TGF-β receptor-1 mRNAs and concomitantly increased phosphorylation of SMAD-2 that indicates the activation of the TGF-β signaling pathway. Therefore, our data reveal that normal expression of β1-integrin in PCs is a critical determinant of CD structural and functional integrity and further support the previously reported critical role of β1-integrin in the development and/or maintenance of the CD structure and function.

Role of Wnt signalling in early pregnancy

The integration of a complex network of signalling molecules promotes implantation of the blastocyst and development of the placenta. These processes are crucial for a successful pregnancy and fetal growth and development. The signalling network involves both cell-cell and cell-extracellular matrix communication. The family of secreted glycoprotein ligands, the Wnts, plays a major role in regulating a wide range of biological processes, including embryonic development, cell fate, proliferation, migration, stem cell maintenance, tumour suppression, oncogenesis and tissue homeostasis. Recent studies have provided evidence that Wnt signalling pathways play an important role in reproductive tissues and in early pregnancy events. The focus of this review is to summarise our present knowledge of expression, regulation and function of the Wnt signalling pathways in early pregnancy events of human and other model systems, and its association with pathological conditions. Despite our recent progress, much remains to be learned about Wnt signalling in human reproduction. The advancement of knowledge in this area has applications in the reduction of infertility and the incidence and morbidity of gestational diseases.

Gain-of-function β-catenin in the uterine mesenchyme leads to impaired implantation and decidualization

Embryo implantation and endometrial decidualization are critical events that occur during early pregnancy in humans and mice, and perturbation in either can result in infertility. WNT signaling through the canonical β-catenin pathway plays a pivotal role in embryonic Müllerian duct development, postnatal uterine maturation and establishment of pregnancy. Loss of β-catenin in the Müllerian duct mesenchyme (MDM)-derived stroma and myometrium results in impaired decidualization and infertility, whereas gain-of-function (GOF) results in the formation of mesenchymal tumors and sub-fertility attributed to malformed oviducts. We hypothesized that GOF β-catenin further contributes to sub-fertility through improper stromal and epithelial cell signaling during embryo implantation and decidualization. We show that mice with GOF β-catenin in MDM-derived stroma and myometrium have reduced implantation sites after embryo transfer and decreased decidualization. On day 4.5 of pseudopregnancy or in mice treated with progesterone and estrogen to mimic early pregnancy, the estrogen-LIF-ERK and progesterone-IHH pathways remain predominantly intact in GOF β-catenin mice; however, JAK/STAT signaling is altered. pSTAT3 is significantly reduced in GOF β-catenin mice and expression of downstream epithelial junctional complex factors, Ctnna1 and Cldn1, is increased. We also show that purified stromal cells from GOF β-catenin uteri, when removed from epithelial cell influence and provided with the appropriate hormonal stimuli, are able to decidualize in vitro indicating that the cells are intrinsically capable of decidualization. Taken together, these results suggest that dysregulated β-catenin activity in the stroma affects epithelial cell STAT3 signaling and ultimately embryo implantation and stromal decidualization.

Specific deletion of LKB1/Stk11 in the Müllerian duct mesenchyme drives hyperplasia of the periurethral stroma and tumorigenesis in male mice

Nearly all older men will experience lower urinary tract symptoms associated with benign prostatic hyperplasia (BPH), the etiology of which is not well understood. We have generated Stk11^CKO mice by conditional deletion of the liver kinase B1 (LKB1) tumor suppressor gene, Stk11 (serine threonine kinase 11), in the fetal Müllerian duct mesenchyme (MDM), the caudal remnant of which is thought to be assimilated by the urogenital sinus primordial mesenchyme in males during fetal development. We show that MDM cells contribute to the postnatal stromal cells at the dorsal aspect of the prostatic urethra by lineage tracing. The Stk11^CKO mice develop prostatic hyperplasia with bladder outlet obstruction, most likely because of stromal expansion. The stromal areas from prostates of Stk11^CKO mice, with or without significant expansion, were estrogen receptor positive, which is consistent with both MD mesenchyme-derived cells and the purported importance of estrogen receptors in BPH development and/or progression. In some cases, stromal hyperplasia was admixed with epithelial metaplasia, sometimes with keratin pearls, consistent with squamous cell carcinomas. Mice with conditional deletion of both Stk11 and Pten developed similar features as the Stk11^CKO mice, but at a highly accelerated rate, often within the first few months after birth. Western blot analyses showed that the loss of LKB1 and phosphatase and tensin homolog deleted on chromosome 10 (PTEN) induces activation of the phospho-5' adenosine monophosphate-activated protein kinase and phospho-AKT serine/threonine kinase 1 signaling pathways, as well as increased total and active β-catenin. These results suggest that activation of these signaling pathways can induce hyperplasia of the MD stroma, which could play a significant role in the etiology of human BPH.

Recent Advances in Uterine Fibroid Etiology

Uterine fibroids, also known as uterine leiomyoma (UL), are monoclonal tumors of the smooth muscle tissue layer (myometrium) of the uterus. Although ULs are considered benign, uterine fibroids are the source of major quality-of-life issues for approximately 25% of all women, who suffer from clinically significant symptoms of UL. Despite the prevalence of UL, there is no treatment option for UL which is long term, cost-effective, and leaves fertility intact. The lack of understanding about the etiology of UL contributes to the scarcity of medical therapies available. Studies have identified an important role for sex steroid hormones in the pathogenesis of UL, and have driven the use of hormonal treatment for fibroids, with mixed results. Dysregulation of cell signaling pathways, miRNA expression, and cytogenetic abnormalities have also been implicated in UL etiology. Recent discoveries on the etiology of UL and the development of relevant genetically modified rodent models of UL have started to revitalize UL research. This review outlines the major characteristics of fibroids; major contributors to UL etiology, including steroid hormones; and available preclinical animal models for UL.

Silencing Med12 Gene Reduces Proliferation of Human Leiomyoma Cells Mediated via Wnt/β-Catenin Signaling Pathway

Uterine fibroids, or leiomyoma, are the most common benign tumors in women of reproductive age. In this work, the effect of silencing the mediator complex subunit 12 (Med12) gene in human uterine fibroid cells was evaluated. The role of Med12 in the modulation of Wnt/β-catenin and cell proliferation-associated signaling was evaluated in human uterine fibroid cells. Med12 was silenced in the immortalized human uterine fibroid cell line (HuLM) using a lentivirus-based Med12 gene-specific RNA interference strategy. HuLM cells were infected with lentiviruses carrying Med12-specific short hairpin RNA (shRNA) sequences or a nonfunctional shRNA scrambled control with green fluorescence protein. Stable cells that expressed low levels of Med12 protein were characterized. Wnt/β-catenin signaling, sex steroid receptor signaling, cell cycle-associated, and fibrosis-associated proteins were measured. Med12 knockdown cells showed significantly (P < 0.05) reduced levels of Wnt4 and β-catenin proteins as well as cell proliferation, as compared with scrambled control cells. Med12 knockdown cells also showed reduced levels of cell cycle-associated cyclin D1, Cdk1, and Cdk2 proteins as well as reduced activation of p-extracellular signal-regulated kinase, p-protein kinase B, and transforming growth factor (TGF)-β signaling pathways as compared with scrambled control cells. Moreover, TGF-β-regulated fibrosis-related proteins such as fibronectin, collagen type 1, and plasminogen activator inhibitor-1 were significantly (P < 0.05) reduced in Med12 knockdown cells as compared with scrambled control cells. Together, these results suggest that Med12 plays a key role in the regulation of HuLM cell proliferation through the modulation of Wnt/β-catenin, cell cycle-associated, and fibrosis-associated protein expression.

Trauma and endometriosis. A review. May we explain surgical phenotypes and natural history of the disease?

OBJECTIVE

The study was performed to evaluate whether trauma is an initial event of development of endometriosis.

METHOD

Using Medline database from January 1960 up to December 2014, a systematic review was made of all published studies using the keywords trauma, healing, injury, infection, hyperperistaltism, stretch and endometriosis, adenomyosis and trauma. Studies and review articles written in French and/or in English related to the topic were included and reviewed independently by two authors.

RESULTS

The role of trauma is well-established for endometriotic lesions diagnosed in surgical scars. Various traumas including delivery, uterine curettage or incision, intraperitoneal hemorrhage, or occult pelvic inflammatory diseases could be involved to explain other localizations of the disease. Many data suggested that the healing process, particularly growth factors and the associated estrogen production, may facilitate the implantation and the growth of ectopic endometrial cells. After the initial, a traumatic event, the phenotype of the disease would depend on the tissue in which the endometriotic lesion grows.

CONCLUSIONS

The present literature review may support a potential role of a trauma as an initial event of endometriosis.