Subtype-Specific Tumor-Associated Fibroblasts Contribute to the Pathogenesis of Uterine Leiomyoma

Serum Calcium and Magnesium Levels in Women with Uterine Fibroids in Southwest Nigeria: a Cross-sectional Study

Studies have suggested the potential roles of serum macronutrients such as calcium and magnesium in the development of uterine fibroids. The primary objective was to assess the association between serum magnesium and calcium levels and the prevalence of uterine fibroids in women of reproductive age. A cross-sectional study of 194 parity-matched women with or without a sonographic diagnosis of uterine fibroids enrolled at a university teaching hospital in Lagos, Southwest Nigeria. Participants' sociodemographic, ultrasound, and anthropometric information as well as the estimated serum levels of calcium and magnesium were collected for statistical analyses. This study found significant negative associations between low serum calcium levels and uterine fibroids (adjusted odds ratio = 0.06), uterine size, and the number of fibroid nodules. However, no significant association was observed between serum magnesium levels and uterine fibroids. This study found significant inverse associations between low serum calcium levels and uterine fibroids, uterine size, and the number of fibroid nodules.

Establishment of Noninvasive Prediction Models for the Diagnosis of Uterine Leiomyoma Subtypes

OBJECTIVE

To establish prediction models for the diagnosis of the subtypes of uterine leiomyomas by machine learning using magnetic resonance imaging (MRI) data.

METHODS

This is a prospective observational study. Ninety uterine leiomyoma samples were obtained from 51 patients who underwent surgery for uterine leiomyomas. Seventy-one samples (49 mediator complex subunit 12 [ MED12 ] mutation-positive and 22 MED12 mutation-negative leiomyomas) were assigned to the primary data set to establish prediction models. Nineteen samples (13 MED12 mutation-positive and 6 MED12 mutation-negative leiomyomas) were assigned to the unknown testing data set to validate the prediction model utility. The tumor signal intensity was quantified by seven MRI sequences (T2-weighted imaging, apparent diffusion coefficient, magnetic resonance elastography, T1 mapping, magnetization transfer contrast, T2* blood oxygenation level dependent, and arterial spin labeling) that can estimate the collagen and water contents of uterine leiomyomas. After surgery, the MED12 mutations were genotyped. These results were used to establish prediction models based on machine learning by applying support vector classification and logistic regression for the diagnosis of uterine leiomyoma subtypes. The performance of the prediction models was evaluated by cross-validation within the primary data set and then finally evaluated by external validation using the unknown testing data set.

RESULTS

The signal intensities of five MRI sequences (T2-weighted imaging, apparent diffusion coefficient, T1 mapping, magnetization transfer contrast, and T2* blood oxygenation level dependent) differed significantly between the subtypes. In cross-validation within the primary data set, both machine learning models (support vector classification and logistic regression) based on the five MRI sequences were highly predictive of the subtypes (area under the curve [AUC] 0.974 and 0.988, respectively). External validation with the unknown testing data set confirmed that both models were able to predict the subtypes for all samples (AUC 1.000, 100.0% accuracy). Our prediction models with T2-weighted imaging alone also showed high accuracy to discriminate the uterine leiomyoma subtypes.

CONCLUSION

We established noninvasive prediction models for the diagnosis of the subtypes of uterine leiomyomas by machine learning using MRI data.

Integrating leiomyoma genetics, epigenomics, and single-cell transcriptomics reveals causal genetic variants, genes, and cell types

Uterine fibroids (UF), that can disrupt normal uterine function and cause significant physical and psychological health problems, are observed in nearly 70% of women of reproductive age. Although heritable genetics is a significant risk factor, specific genetic variations and gene targets causally associated with UF are poorly understood. Here, we performed a meta-analysis on existing fibroid genome-wide association studies (GWAS) and integrated the identified risk loci and potentially causal single nucleotide polymorphisms (SNPs) with epigenomics, transcriptomics, 3D chromatin organization from diverse cell types as well as primary UF patient's samples. This integrative analysis identifies 24 UF-associated risk loci that potentially target 394 genes, of which 168 are differentially expressed in UF tumors. Critically, integrating this data with single-cell gene expression data from UF patients reveales the causal cell types with aberrant expression of these target genes. Lastly, CRISPR-based epigenetic repression (dCas9-KRAB) or activation (dCas9-p300) in a UF disease-relevant cell type further refines and narrows down the potential gene targets. Our findings and the methodological approach indicate the effectiveness of integrating multi-omics data with locus-specific epigenetic editing approaches for identifying gene- and celt type-targets of disease-relevant risk loci.

Novel Approaches to Possible Targeted Therapies and Prophylaxis of Uterine Fibroids

Uterine leiomyomas are the most common benign tumors in women of childbearing age. They may lead to problems of conception or complications during the gestational period. The methods of treatment include surgical (myomectomy and hysterectomy, embolization of arteries) and therapeutic treatment (ulipristal acetate, leuprolide acetate, cetrorelix, goserelin, mifepristone). Both approaches are efficient but incompatible with pregnancy planning. Therefore, there is a call for medical practice to develop therapeutical means of preventing leiomyoma onset in patients planning on becoming pregnant. Based on the analysis of GWAS data on the search for mononucleotide polymorphisms associated with the risk of leiomyoma, in meta-transcriptomic and meta-methylomic studies, target proteins have been proposed. Prospective therapeutic treatments of leiomyoma may be based on chemical compounds, humanized recombinant antibodies, vaccines based on markers of the uterine leiomyoma cells that are absent in the adult organism, or DNA and RNA preparations. Three different nosological forms of the disease associated with driver mutations in the MED12, HMGA2, and FH genes should be considered when developing or prescribing drugs. For example, synthetic inhibitors and vaccines based on matrix metalloproteinases MMP11 and MMP16 are expected to be effective only for the prevention of the occurrence of MED12-dependent nodules.

Engineered MED12 mutations drive leiomyoma-like transcriptional and metabolic programs by altering the 3D genome compartmentalization

Nearly 70% of Uterine fibroid (UF) tumors are driven by recurrent MED12 hotspot mutations. Unfortunately, no cellular models could be generated because the mutant cells have lower fitness in 2D culture conditions. To address this, we employ CRISPR to precisely engineer MED12 Gly44 mutations in UF-relevant myometrial smooth muscle cells. The engineered mutant cells recapitulate several UF-like cellular, transcriptional, and metabolic alterations, including altered Tryptophan/kynurenine metabolism. The aberrant gene expression program in the mutant cells is, in part, driven by a substantial 3D genome compartmentalization switch. At the cellular level, the mutant cells gain enhanced proliferation rates in 3D spheres and form larger lesions in vivo with elevated production of collagen and extracellular matrix deposition. These findings indicate that the engineered cellular model faithfully models key features of UF tumors and provides a platform for the broader scientific community to characterize genomics of recurrent MED12 mutations.

Serum Calcium and Magnesium Levels in Women with Uterine Fibroids at a University Teaching Hospital in Southwest Nigeria: A Comparative Cross-Sectional Study

Background: Studies have suggested the potential roles of serum trace elements such as calcium and magnesium in the development of uterine fibroids. Aims: This study compared magnesium and calcium serum levels in reproductive-age women with and without uterine fibroids in Lagos, Southwest Nigeria. Methods: A comparative cross-sectional study of 194 parity-matched women with or without a sonographic diagnosis of uterine fibroids enrolled at a university teaching hospital in Lagos, Southwest Nigeria. Participants' sociodemographic, ultrasound, and anthropometric information as well as the estimated serum levels of calcium and magnesium were collected for statistical analyses. Results: This study found significant negative associations between low serum calcium levels and uterine fibroids (adjusted odds ratio= 0.06; 95% CI: 0.004, 0.958; p=0.047), uterine size (p=0.004), and the number of fibroid nodules (p=0.030). However, no significant association was observed between serum magnesium levels and uterine fibroids (p=0.341). Conclusion: The findings of this study suggest the promising role of calcium-rich diets and supplements in the prevention of uterine fibroids among Nigerian women. However, future longitudinal studies are required to further evaluate the potential role of these trace mineral elements in the development of uterine fibroids.

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.

Engineered MED12 mutations drive uterine fibroid-like transcriptional and metabolic programs by altering the 3D genome compartmentalization

Uterine fibroid (UF) tumors originate from a mutated smooth muscle cell (SMC). Nearly 70% of these tumors are driven by hotspot recurrent somatic mutations in the MED12 gene; however, there are no tractable genetic models to study the biology of UF tumors because, under culture conditions, the non-mutant fibroblasts outgrow the mutant SMC cells, resulting in the conversion of the population to WT phenotype. The lack of faithful cellular models hampered our ability to delineate the molecular pathways downstream of MED12 mutations and identify therapeutics that may selectively target the mutant cells. To overcome this challenge, we employed CRISPR knock-in with a sensitive PCR-based screening strategy to precisely engineer cells with mutant MED12 Gly44, which constitutes 50% of MED12 exon two mutations. Critically, the engineered myometrial SMC cells recapitulate several UF-like cellular, transcriptional and metabolic alterations, including enhanced proliferation rates in 3D spheres and altered Tryptophan/kynurenine metabolism. Our transcriptomic analysis supported by DNA synthesis tracking reveals that MED12 mutant cells, like UF tumors, have heightened expression of DNA repair genes but reduced DNA synthesis rates. Consequently, these cells accumulate significantly higher rates of DNA damage and are selectively more sensitive to common DNA-damaging chemotherapy, indicating mutation-specific and therapeutically relevant vulnerabilities. Our high-resolution 3D chromatin interaction analysis demonstrates that the engineered MED12 mutations drive aberrant genomic activity due to a genome-wide chromatin compartmentalization switch. These findings indicate that the engineered cellular model faithfully models key features of UF tumors and provides a novel platform for the broader scientific community to characterize genomics of recurrent MED12 mutations and discover potential therapeutic targets.

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.

A mediator complex subunit 12 gain-of-function mutation induces partial leiomyoma cell properties in human uterine smooth muscle cells

OBJECTIVE

To clarify whether a mediator complex subunit 12 (MED12) gain-of-function mutation induces leiomyoma cell properties in human uterine smooth muscle cells (USMCs).

DESIGN

Experimental study.

SETTING

Academic research laboratory.

PATIENT(S)

Women undergoing hysterectomy for leiomyoma.

INTERVENTION(S)

CRISPR/Cas9-mediated genome editing to introduce an MED12 gain-of-function mutation (G44D) into human USMCs.

MAIN OUTCOME MEASURE(S)

Cell proliferation, collagen production, and in vivo tumorigenicity of USMCs with vs. without the MED12 mutation.

RESULT(S)

Uterine smooth muscle cells isolated from the uterine myometrium of a 44-year-old patient were subjected to lentiviral vector-mediated gene transduction of the fluorescent protein Venus, followed by long-term passage. Uterine smooth muscle cells with a normal female karyotype, high cell proliferative activity, and Venus expression, but without stem/progenitor cell populations, were obtained and designated as USMC44. Using CRISPR/Cas9-mediated genome editing, mtUSMC44 (MED12, 131G>A, p.G44D) and mock USMC44 without MED12 mutation (wtUSMC44) were established from USMC44. wtUSMC44 and mtUSMC44 showed similar cell proliferation activity, even in the presence of estradiol and progesterone (EP) together with transforming growth factor-beta 3 (TGFB3). In addition, wtUSMC44 and mtUSMC44 generated similar tiny smooth muscle-like tissue constructs when xenotransplanted beneath the kidney capsule in immunodeficient mice treated with EP alone or TGFB3. In contrast, mtUSMC44 produced more collagen type I than wtUSMC in vitro, and this production was likely enhanced by EP and TGFB3.

CONCLUSION(S)

The results suggest that the MED12 gain-of-function mutation is involved in collagen production. Although approximately 70% of leiomyomas have MED12 mutations, additional factors and/or events other than MED12 and/or myometrial stem/progenitor cells may be required for fully inducing leiomyoma cell properties, including transformation, in USMCs.

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.

Different DNA methylome, transcriptome and histological features in uterine fibroids with and without MED12 mutations

Somatic mutations in Mediator complex subunit 12 (MED12m) have been reported as a biomarker of uterine fibroids (UFs). However, the role of MED12m is still unclear in the pathogenesis of UFs. Therefore, we investigated the differences in DNA methylome, transcriptome, and histological features between MED12m-positive and -negative UFs. DNA methylomes and transcriptomes were obtained from MED12m-positive and -negative UFs and myometrium, and hierarchically clustered. Differentially expressed genes in comparison with the myometrium and co-expressed genes detected by weighted gene co-expression network analysis were subjected to gene ontology enrichment analyses. The amounts of collagen fibers and the number of blood vessels and smooth muscle cells were histologically evaluated. Hierarchical clustering based on DNA methylation clearly separated the myometrium, MED12m-positive, and MED12m-negative UFs. MED12m-positive UFs had the increased activities of extracellular matrix formation, whereas MED12m-negative UFs had the increased angiogenic activities and smooth muscle cell proliferation. The MED12m-positive and -negative UFs had different DNA methylation, gene expression, and histological features. The MED12m-positive UFs form the tumor with a rich extracellular matrix and poor blood vessels and smooth muscle cells compared to the MED12m-negative UFs, suggesting MED12 mutations affect the tissue composition of UFs.

Progesterone Actions and Resistance in Gynecological Disorders

Estrogen and progesterone and their signaling mechanisms are tightly regulated to maintain a normal menstrual cycle and to support a successful pregnancy. The imbalance of estrogen and progesterone disrupts their complex regulatory mechanisms, leading to estrogen dominance and progesterone resistance. Gynecological diseases are heavily associated with dysregulated steroid hormones and can induce chronic pelvic pain, dysmenorrhea, dyspareunia, heavy bleeding, and infertility, which substantially impact the quality of women’s lives. Because the menstrual cycle repeatably occurs during reproductive ages with dynamic changes and remodeling of reproductive-related tissues, these alterations can accumulate and induce chronic and recurrent conditions. This review focuses on faulty progesterone signaling mechanisms and cellular responses to progesterone in endometriosis, adenomyosis, leiomyoma (uterine fibroids), polycystic ovary syndrome (PCOS), and endometrial hyperplasia. We also summarize the association with gene mutations and steroid hormone regulation in disease progression as well as current hormonal therapies and the clinical consequences of progesterone resistance.

Uterine Fibroids: Hiding in Plain Sight

Uterine fibroids (leiomyomas) are present in >75% of women and can cause serious morbidity. They are by far the leading cause of hysterectomy. Fibroids are a complex mixture of cells that include fibroblasts and smooth muscle cells. Rich in extracellular matrix, they typically arise through somatic mutations, most commonly MED12. Their lack of growth inhibition and their ability to have facets of malignancy yet be histologically and biologically benign provide opportunities to explore basic processes. To date, the mechanisms responsible for growth and development of leiomyomas are an enigma. This review provides an overview of current understanding and future directions for clinical and basic research of fibroids.

Pathogenesis, diagnosis and treatment of uterine lipoleiomyoma: A review

Uterine lipoleiomyomas are variants of uterine leiomyomas and are characterized by progressive enlargement that can occur even after menopause. These tumors can produce serious clinical symptoms and are difficult to diagnosis preoperatively. The growth rate of uterine lipoleiomyomas after menopause is comparatively higher than that of conventional uterine leiomyomas, and lipoleiomyosarcomas as well as tumor-to-tumor metastasis associated with lipoleiomyomas have been reported. However, detailed histogenic mechanisms of the tumor remain unclear. Surgical treatments are the current choice for the management of lipoleiomyomas. The purpose of this review is to promote greater awareness of lipoleiomyoma characteristics with a focus on histogenesis, diagnosis, and treatment. We performed an exhaustive literature review and have summarized the available data. We assessed the interpretation of auxiliary examinations to help physicians in making an early accurate diagnosis of the disease and to help with treatment decision-making, particularly regarding whether surgery should be performed or avoided.

Co-administration of Aluminum Sulfate and Propolis Regulates Matrix Metalloproteinases-2/9 Expression and Improves the Uterine Leiomyoma in Adult Rat Model

The aim of this study was to evaluate the effects of aluminum sulfate (alum) with propolis (PR) on uterine leiomyoma (UL) in rat model. One hundred and four female Wistar rats (180-200 g) were allocated into two main groups of control (Co, n = 8) and experiment (UL model [estradiol benzoate 200 μg/kg/IM twice/week/8 weeks] with/without treatment) defined in 13 subgroups with/without treatment with coil oil (UL + COi), PR (100 or 200 mg/kg) as UL + PR100 or 200, alum (35, 75 or 150 mg/Kg) as UL + AL 35, 75, or 150, and PR (100 mg/kg or 200) with alum (35, 75, or 150 mg/Kg) as UL + PR100 or 200 + AL35, 75, or 150. Subgroups received doses of therapeutics for 14 days (IP). In the end, rats were sacrificed, and the uteri were isolated for molecular and histopathological investigations. The myometrium thickness, collagen contents, and gene expression of MMP-2 and 9 increased significantly in experimental groups with/without treatment (P ˂ 0.05). PR administration (100 and 200 mg/kg) alone or with alum (35 and 75 mg/kg) significantly decreased myometrium collagen contents and the gene expression and protein concentration of MMP-2 and 9 compared with UL and UL + Coi subgroups (P ˂ 0.05). Alum (75 mg/kg) with PR (200 mg/kg) could improve UL features and reduce MMP-2 and 9 gene expression.

An HMGA2-p62-ERα axis regulates uterine leiomyomas proliferation

Uterine leiomyomas (ULM) are a major public health issue contributing to high morbidity and poor pregnancy outcomes. However, its molecular pathogenesis is poorly understood. HMGA2-ULM is the second major subtype of human ULM and associates with large sizes, fast-growth, and high percentages of estrogen receptor α (ERα). As altered ERα expression plays a distinct role in ULM growth, here, we investigate a regulatory mechanism driving ULM growth via HMGA2 and ERα. We reveal a positive correlation of HMGA2 with ERα protein and demonstrate that HMGA2 promotes ULM cells proliferation via ERα. In addition, autophagy pathway and p62/SQSTM1 (a selective autophagy receptor) are found to participate in the regulation of HMGA2 and ERα. Moreover, HMGA2 suppresses the transcription of p62 by binding to its promoter, meanwhile, p62 interacts with ERα, and inhibition of p62 increases ERα expression and enhances cell viability in ULM, suggesting a novel mechanism of the HMGA2-p62-ERα axis in ULM proliferation. Notably, rapamycin, a familiar autophagy agonist, reduces ERα levels and the proliferation ability of ULM cells. This study demonstrates a causal role of the HMGA2-p62-ERα axis in preventing autophagy and increasing ERα expression in HMGA2-ULM. Therefore, blocking HMGA2-p62-ERα axis and targeting autophagy pathway establish a roadmap toward HMGA2-ULM medical treatment.

Reasons to Reconsider Risk Associated With Power Morcellation of Uterine Fibroids

Our insights into the molecular pathogenesis of uterine smooth muscle tumors have improved significantly. Accordingly, in the present review, we advocate a more refined risk assessment for patients considering surgical removal of fibroids or hysterectomy, respectively, requiring morcellation. For this procedure, the risk estimates given for the iatrogenic spread of a previously unexpected malignancy considerably vary among different studies. Nearly all previous studies conducted retrospectively refer to the risk of a patient having an unexpected malignancy at the time of surgery. We feel that, more appropriately, risk should refer to the number of tumors because, as a rule, every single nodule arises independently and, thus, carries an independent risk of being malignant or not. Furthermore, whether so-called parasitic fibroids carry an underestimated risk of stepwise malignant transformation is discussed.

Organotypic culture as a research and preclinical model to study uterine leiomyomas

Organotypic cultures of tissue slices have been successfully established in lung, prostate, colon, gastric and breast cancer among other malignancies, but until now an ex vivo model based on tissue slices has not been established for uterine leiomyoma. In the present study, we describe a method for culturing tumour slides onto an alginate scaffold. Morphological integrity of tissue slices was maintained for up to 7 days of culture, with cells expressing desmin, estrogen and progesterone receptors. Driver mutations were present in the ex vivo slices at all-time points analyzed. Cultivated tumour slices responded to ovarian hormones stimulation upregulating the expression of genes involved in leiomyoma pathogenesis. This tissue model preserves extracellular matrix, cellular diversity and genetic background simulating more in-vivo-like situations. As a novelty, this platform allows encapsulation of microspheres containing drugs that can be tested on the ex vivo tumour slices. After optimizing drug release rates, microspheres would then be directly tested in animal models through local injection.

Interactome Analysis of the Differentially Expressed Proteins in Uterine Leiomyoma

BACKGROUND

Recent advances in proteomics present enormous opportunities to discover proteome related disparities and thus understanding the molecular mechanisms related to a disease. Uterine leiomyoma is a benign monoclonal tumor, located in the pelvic region, and affecting 40% of reproductive aged female.

OBJECTIVE

Identification and characterization of the differentially expressed proteins associated with leiomyogenesis by comparing uterine leiomyoma and normal myometrium.

METHODS

Paired samples of uterine leiomyoma and adjacent myometrium retrieved from twenty-five females suffering from uterine leiomyoma (n=50) were submitted to two-dimensional electrophoresis (2-DE), matrixassisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) and to reverse transcription polymerase chain reaction (RT-PCR).

RESULTS

Comparison of protein patterns revealed seven proteins with concordantly increased spot intensities in leiomyoma samples. E3 ubiquitin-protein ligase MIB2 (MIB2), Mediator of RNA polymerase II transcription subunit 10 (MED10), HIRA-interacting protein (HIRP3) and Fatty acid binding protein brain (FABP7) were found to be upregulated. While, Biogenesis of lysosome-related organelles complex 1 subunit 2 (BL1S2), Shadow of prion protein (SPRN) and RNA binding motif protein X linked like 2 (RMXL2) were found to be exclusively present in leiomyoma sample. The expression modulations of the corresponding genes were further validated which corroborated with the 2-DE result showing significant upregulation in leiomyoma. We have generated a master network showing the interactions of the experimentally identified proteins with their close neighbors and further scrutinized the network to prioritize the routes leading to cell proliferation and tumorigenesis.

CONCLUSION

This study highlights the importance of identified proteins as potential targets for therapeutic purpose. This work provides an insight into the mechanism underlying the overexpression of the proteins but warrants further investigations.

Moving Toward Individualized Medicine for Uterine Leiomyomas

Uterine leiomyomas are common and life-altering for many women. Despite a wide range of symptoms, varying characteristics of the uterus and the leiomyomas themselves, and many alternatives, hysterectomy accounts for almost three fourths of all surgical therapy, yet there is increasing evidence for a variety of procedural therapies for symptomatic leiomyomas and a new generation of medical therapies under development. With increasing evidence of long-term risk from hysterectomy and new data regarding leiomyoma biology, individualized medical approaches to leiomyomas are likely in the near future. Key biological attributes that influence this disease process are common driver mutations and the new appreciation of the interaction of smooth muscle cells and fibroblasts. Additionally, the interaction between cell types and steroid hormone responsiveness likely plays a role in pathogenesis that can be leveraged in individualized therapy. However, given the independent clonal nature of leiomyomas within the same uterus, moving in the direction of biopsies for individual leiomyomas to understand the biology is unlikely to be fruitful. Use of advanced imaging will likely continue to evolve not only to accurately predict malignant disease, including sarcomas, but to predict leiomyoma subtypes, response to therapy, or both. We predict the continued evolution of therapy from excisional or interventional therapies to medical therapies and ultimately prediction of at-risk individuals. Ideally, individualized therapies will offer primary prevention for women at high risk of leiomyomas and secondary prevention after initial treatment.

Comparative analysis of AKT and the related biomarkers in uterine leiomyomas with MED12, HMGA2, and FH mutations

Uterine leiomyomas (ULM) are histologically and molecularly heterogeneous and clinically they grow at vastly different rates. Several driver gene mutations have been identified in ULM, including MED12 mutations, HMGA2 overexpression, and biallelic FH inactivation. ULM with different driver mutant genes may use different molecular pathways, but currently no clear correlation between gene mutations and growth related pathways has been established. To better define this relationship, we collected ULM with MED12 (n = 25), HMGA2 (n = 15), and FH (n = 27) mutations and examined the sex steroid hormone, cell cycle, and AKT pathway genes by immunohistochemistry. While ER and PR were highly expressed in all types of ULM, FH ULM showed lower ER expression and higher PR expression. HMGA2 tumors had significantly higher levels of AKT signaling and mitogenic activity than other ULM types. HMGA2 activated AKT signaling through upregulation of IGF2BP2. Silencing HMGA2 in ULM cells resulted in downregulation of AKT and upregulation of p16 and p21, which eventually led to cell senescence. HMGA2 overexpression in ULM is not only related to tumor development but also plays a role in controlling cellular proliferation through the AKT pathway.

Cellular kinetics of MED12-mutant uterine leiomyoma growth and regression in vivo

Cellular mechanisms of uterine leiomyoma (LM) formation have been studied primarily utilizing in vitro models. However, recent studies established that the cells growing in the primary cultures of MED12-mutant LM (MED12-LM) do not carry causal mutations. To improve the accuracy of LM research, we addressed the cellular mechanisms of LM growth and regression utilizing a patient-derived xenograft (PDX) model, which faithfully replicates the patient tumors in situ The growth and maintenance of MED12-LMs depend on 17β-estradiol (E2) and progesterone (P4). We determined E2 and P4-activated MAPK and PI3K pathways in PDXs with upregulation of IGF1 and IGF2, suggesting that the hormone actions on MED12-LM are mediated by the IGF pathway. When hormones were removed, MED12-LM PDXs lost approximately 60% of volume within 3 days through reduction in cell size. However, in contrast to general belief, the survival of LM cells was independent of E2 and/or P4, and apoptosis was not involved in the tumor regression. Furthermore, it was postulated that abnormal collagen fibers promote the growth of LMs. However, collagen fibers of actively growing PDXs were well aligned. The disruption of collagen fibers, as found in human LM specimens, occurred only when the volume of PDXs had grown to over 20 times the volume of unstimulated PDXs, indicating disruption is the result of growth not the cause. Hence, this study revises generally accepted theories on the growth and regression of LMs.

Patient-derived xenograft model for uterine leiomyoma by sub-renal capsule grafting

Uterine leiomyoma (UL) or fibroid is a benign smooth muscle tumor of the myometrium with a lifetime incidence of approximately 70%. ULs often require medical intervention due to severe symptoms such as heavy menstrual bleeding and abdominal pain. Although the most common and effective management of ULs is surgical removal, the invasive surgical procedure imposes physical and psychological burdens on the patients. Moreover, the economic burden of UL on health care system is enormous due to the high cost of surgeries. Thus, therapeutic options with long-term efficacy to replace surgical management are urgently needed. For the development of such medical options, reliable preclinical research models are imperative. Ex vivo culture of UL cells has been the primary research model for decades. However, recent studies demonstrated that primary cell culture is not a suitable model for UL research, as primary cultures of ULs mostly consist of non-tumor fibroblasts. Here we describe the protocol for patient-derived xenograft of UL, which faithfully replicates the phenotypes of human UL in situ.

Factors targeting MED12 to drive tumorigenesis?

Mediator Complex Subunit 12 (MED12) is part of the transcriptional preinitiation machinery. Mutations of its gene predominantly occur in two types of highly frequent benign tumors, uterine leiomyomas and fibroadenomas of the breast, where they apparently act as driver mutations. Nevertheless, their presence is not restricted to benign tumors having been found at considerable frequencies in uterine leiomyosarcomas, malignant phyllodes tumors, and chronic lymphocytic leukemia also. Most of the mutations are located within exon 2 of the gene but in rare cases the intron 1/exon 2 boundary or exon 1 are affected. As to their type, predominantly single nucleotide exchanges with a hotspot in one codon are found, but small deletions clustering around that hotspot also are not uncommon. These latter deletions are leaving the open reading frame intact. As to the types of mutations, so far no apparent differences between the tumor entities affected have emerged. Interestingly, this pattern with small deletions clustered around the hotspot of single nucleotide exchanges resembles that seen as a result of targeted gene editing. In contrast to other driver mutations the percentage of MED12-mutation positive tumors of independent clonal origin increases with the number of tumors per patient suggesting unknown etiological factors supporting site specific mutagenesis.  These factors may act by inducing simultaneous site-specific double strand breaks the erroneous repair of which may lead to corresponding mutations. As inducers of DNA damage and its repair such as foreign nucleic acids of the microbiome displaying sequence homology to the putative target site might play a role. Interestingly, a 16 base pair homology of the hotspot to a putative terminator base-paired hairpin sequence of a Staphylococcus aureus tRNA gene cluster has been noted which might form R-loop like structures with its target sequence thus inducing said changes.

Successes and failures of uterine leiomyoma drug discovery

INTRODUCTION

To-date, the only cure for symptomatic uterine fibroids (UFs) is surgical intervention. However, surgery may eliminate the hope of future pregnancies; moreover, the intrinsic risks of surgery make it a less favorable to women with UFs. Because of this, conservative medical therapies have become an attractive and prior option for those women. Leuprolide acetate (LA), a gonadotropin-releasing hormone (GnRH) agonist, is the only pharmacological agent currently approved for the short-term and pre-operative management of symptomatic UFs in the USA. Areas covered: This systematic review covers the successes and failures of prominent drugs that have been researched for UFs in the past and agents that have shown promise in recent clinical trials. The most recent clinical trials and advances in drug therapy are presented in a comprehensive overview outlining the direction UF drug discovery is heading. Expert opinion: Experts in the field are already on the forefront leading the responsibility to uncover potential drugs as long term fertility friendly viable options for non-invasive treatment/prevention of UFs. Indeed, a shift in the UF management is expected in the future.