Raf kinase inhibitor protein expression in smooth muscle tumours of the uterus: a diagnostic marker for leiomyosarcoma?

RESEARCH QUESTION: What is the expression pattern of Raf kinase inhibitory protein (RKIP) in different subtypes of leiomyoma (usual type, cellular, apoplectic or haemorrhagic leiomyoma, leiomyoma with bizarre nuclei and lipoleiomyoma) and leiomyosarcoma specimens, and what is its biological role in leiomyosarcoma cells? DESIGN: Leiomyoma and leiomyosarcoma specimens underwent immunohistochemistry staining. Leiomyosarcoma SK-LMS-1 cell line was RKIP knocked down and RKIP overexpressed, and cell viability, wound healing migration and clonogenicity assays were carried out. RESULTS: A higher immunohistochemical expression of RKIP was observed in bizarre leiomyomas, than in usual-type leiomyomas. Decreased expression was also found in cellular leiomyoma, with generally absent staining in leiomyosarcomas. Upon RKIP expression manipulation in SK-LMS-1 cell line, no major differences were observed in cell viability and migration capacity over time. RKIP knockout, however, resulted in a significant increase in the cell's ability to form colonies (P = 0.011). CONCLUSION: RKIP distinct expression pattern among leiomyoma histotype and leiomyosarcoma, and its effect on leiomyosarcoma cells on colony formation, encourages further studies of RKIP in uterine smooth muscle disorders.

Impact of Nutrition on Female Reproductive Disorders.

The female reproductive system is a delicate and complex system in the body that can be affected by many disorders [...].

The In Vitro Effects of Romina Strawberry Extract on 3D Uterine Leiomyosarcoma Cells.

Leiomyosarcoma is an aggressive soft tissue sarcoma derived from the smooth muscle cells of the uterus. We tested the effect of Romina strawberry extract treatment on three-dimensional cultured uterine leiomyosarcoma cells. We established 3D cultures in agarose gel, where the cells seeded were able to form spheroids. We performed the observation and counting of the spheroids with a phase-contrast optical microscope, finding a decrease in the number of spheroids formed in the plates after 24 and 48 h treatment with 250 µg/mL of cultivar Romina strawberry extract. We also characterized the spheroids morphology by DNA binding fluorescent-stain observation, hematoxylin and eosin stain, and Masson's trichrome stain. Finally, the real-time PCR showed a reduced expression of extracellular matrix genes after strawberry treatment. Overall, our data suggest that the fruit extract of this strawberry cultivar may be a useful therapeutic adjuvant for the management of uterine leiomyosarcoma.

High levels of hypusinated eIF5A in leiomyoma and leiomyosarcoma pathologies: a possible novel therapeutic target.

RESEARCH QUESTION: Is the hypusinated form of the eukaryotic translation initiation factor 5A (EIF5A) present in human myometrium, leiomyoma and leiomyosarcoma, and does it regulate cell proliferation and fibrosis? DESIGN: The hypusination status of eIF5A in myometrial and leiomyoma patient-matched tissues was evaluated by immunohistochemistry and Western blotting as well as in leiomyosarcoma tissues by immunohistochemistry. Myometrial, leiomyoma and leiomyosarcoma cell lines were treated with N1-guanyl-1,7-diaminoheptane (GC-7), responsible for the inhibition of the first step of eIF5A hypunization, and the proliferation rate was determined by MTT assay; fibronectin expression was analysed by Western blotting. Finally, expression of fibronectin in leiomyosarcoma tissues was detected by immunohistochemistry. RESULTS: The hypusinated form of eIF5A was present in all tissues examined, with an increasing trend of hypusinated eIF5A levels from normal myometrium to neoplastic benign leiomyoma up to neoplastic malignant leiomyosarcoma. The higher levels in leiomyoma compared with myometrium were confirmed by Western blotting (P = 0.0046). The inhibition of eIF5A hypusination, with GC-7 treatment at 100 nM, reduced the cell proliferation in myometrium (P = 0.0429), leiomyoma (P = 0.0030) and leiomyosarcoma (P = 0.0044) cell lines and reduced the expression of fibronectin in leiomyoma (P = 0.0077) and leiomyosarcoma (P = 0.0280) cells. The immunohistochemical staining of leiomyosarcoma tissue revealed that fibronectin was highly expressed in the malignant aggressive (central) part of the leiomyosarcoma lesion, where hypusinated eIF5A was also highly represented. CONCLUSIONS: These data support the hypothesis that eIF5A may be involved in the pathogenesis of myometrial benign and malignant pathologies.

Uterine leiomyoma as useful model to unveil morphometric and macromolecular collagen state and impairment in fibrotic diseases: An ex-vivo human study.

Collagen is one of the main components of the extracellular matrix (ECM), involved, among all, in the maintenance of the structural support of tissues. In fibrotic diseases, collagen is overexpressed, and its production determines the formation of a significantly stiffer ECM. The cross-linking of high-resolution analytical tools, able to investigate both the tridimensional organization and the secondary structure of collagen in fibrotic diseases, could be useful to identify defined markers correlating the status of this protein with specific pathological conditions. To this purpose, an innovative multidisciplinary approach based on Phase-Contrast MicroComputed Tomography, Transmission Electron Microscopy, and Fourier Transform Infrared Imaging Spectroscopy was exploited on leiomyoma samples and adjacent myometrium to characterize microstructural collagen features. Uterine leiomyoma is a common gynecological disorder affecting women in fertile age. It is characterized by a massive collagen production due to the repairing processes occurring at myometrium level, and, hence, it represents a valuable model to investigate collagen self-organization in a pathological condition. Moreover, to evaluate the sensitivity of this multidisciplinary approach, the effects of eicosapentaenoic (EPA) and docosahexaenoic (DHA) omega-3 fatty acids in collagen reduction were also investigated.

Nutrition in Gynecologic Disease.

The pathologies concerning the gynecological organs are very varied and range from tumoral pathologies to hormonal dysfunctions [...].

Uterine fibroid vascularization: from morphological evidence to clinical implications.

Uterine fibroids are the most common cause of solid pelvic tumours, occurring in 20-30% of fertile women and presenting clinical complications that seriously affect women's health. They commonly cause severe symptoms, such as heavy, prolonged menstrual bleeding and anaemia. The study of microscopic and macroscopic vascular aspects of uterine fibroids is important for understanding the clinical manifestations of uterine fibroids, for predicting the effectiveness of alternative treatments to surgery, i.e. uterine artery embolization, for improving surgery outcomes and for carrying out a differential diagnosis with other benign conditions, e.g. adenomyosis, or malignancy, e.g. leiomyosarcoma, and to develop new therapeutic approaches. In this review, current knowledge of how the vascular network and angiogenesis are implied in the formation of uterine fibroids and in the pathogenesis of related symptoms is explored, and evidence on the role of ultrasound in evaluating fibroid vascularization is summarized. This review combines anatomical, morphological and biomolecular information related to angiogenic mechanisms with diagnostic and clinical information, highlighting the various interconnections. Uterine and fibroid vascularization need further investigation to gain a deeper understanding of the pathogenetic elements that lead to the formation of uterine fibroids and their clinical manifestations.

Phytoprogestins: Unexplored Food Compounds with Potential Preventive and Therapeutic Effects in Female Diseases.

In recent years, there has been an increasing interest in natural therapies to prevent or treat female diseases. In particular, many studies have focused on searching natural compounds with less side effects than standard hormonal therapies. While phytoestrogen-based therapies have been extensively studied, treatments with phytoprogestins reported in the literature are very rare. In this review, we focused on compounds of natural origin, which have progestin effects and that could be good candidates for preventing and treating female diseases. We identified the following phytoprogestins: kaempferol, apigenin, luteolin, and naringenin. In vitro studies showed promising results such as the antitumoral effects of kaempferol, apigenin and luteolin, and the anti-fibrotic effects of naringenin. Although limited data are available, it seems that phytoprogestins could be a promising tool for preventing and treating hormone-dependent diseases.

Macrophages and Immune Responses in Uterine Fibroids.

Uterine fibroids represent the most common benign tumors of the uterus. They are considered a typical fibrotic disorder. In fact, the extracellular matrix (ECM) proteins-above all, collagen 1A1, fibronectin and versican-are upregulated in this pathology. The uterine fibroids etiology has not yet been clarified, and this represents an important matter about their resolution. A model has been proposed according to which the formation of an altered ECM could be the result of an excessive wound healing, in turn driven by a dysregulated inflammation process. A lot of molecules act in the complex inflammatory response. Macrophages have a great flexibility since they can assume different phenotypes leading to the tissue repair process. The dysregulation of macrophage proliferation, accumulation and infiltration could lead to an uncontrolled tissue repair and to the consequent pathological fibrosis. In addition, molecules such as monocyte chemoattractant protein-1 (MCP-1), granulocyte macrophage-colony-stimulating factor (GM-CSF), transforming growth factor-beta (TGF-ß), activin A and tumor necrosis factor-alfa (TNF-α) were demonstrated to play an important role in the macrophage action within the uncontrolled tissue repair that contributes to the pathological fibrosis that represents a typical feature of the uterine fibroids.

Sphingosine 1-phosphate signaling in uterine fibroids: implication in activin A pro-fibrotic effect.

OBJECTIVE: To explore the link between sphingosine 1-phosphate (S1P) signaling and leiomyoma and the possible S1P cross-talk with the fibrotic effect of activin A. DESIGN: Case-control laboratory study. SETTING: University institute and university hospital. PATIENT(S): Patients with uterine fibroids (n = 26). INTERVENTIONS(S): Tissue specimens of leiomyoma and normal myometrium were obtained from patients undergoing myomectomy or total hysterectomy. MAIN OUTCOME MEASURE(S): Expression of mRNA levels of the enzyme involved in S1P metabolism, S1P receptors, and S1P transporter Spns2 was evaluated in matched leiomyoma/myometrium specimens and cell populations. The effects of inhibition of S1P metabolism and signaling was evaluated on activin A-induced fibrotic action in leiomyoma cell lines. RESULT(S): The expression of the enzymes responsible for S1P formation, sphingosine kinase (SK) 1 and 2, and S1P2, S1P3, and S1P5 receptors was significantly augmented in leiomyomas compared with adjacent myometrium. In leiomyoma cells, but not in myometrial cells, activin A increased mRNA expression levels of SK1, SK2, and S1P2. The profibrotic action of activin A was abolished when SK1/2 were inhibited or S1P2/3 were blocked. Finally, S1P augmented by itself mRNA levels of fibrotic markers (fibronectin, collagen 1A1) and activin A in leiomyomas but not in myometrial cells. CONCLUSION(S): This study shows that S1P signaling is dysregulated in uterine fibroids and involved in activin A-induced fibrosis, opening new perspectives for uterine fibroid treatment.

Hop and artichoke extracts inhibit expression of extracellular matrix components in uterine leiomyoma cells.

OBJECTIVE: To screen 14 different plant extracts for their antifibrotic effect on human primary leiomyoma and healthy myometrial cells. DESIGN: Preclinical study. SETTING: University research laboratory. PATIENT(S): Human uterine leiomyoma and matched myometrial tissues were obtained from Caucasian premenopausal women with symptomatic uterine fibroids at the time of hysterectomy. INTERVENTION(S): Primary human leiomyoma and myometrial cells were cultured in the absence or presence of the plant extracts. MAIN OUTCOME MEASURE(S): Quantification of the expression of extracellular matrix components, such as fibronectin 1 (FN1), collagen type I alpha 1 (COL1A1), and versican (VCAN), and the profibrotic growth factor activin A or inhibin beta A subunit (INHBA). RESULT(S): The cells were treated with the 14 extracts for 48 hours, and we measured FN1 messenger RNA (mRNA) expression. Of the 14 extracts, about (ABO) ABO-2 (hop) and ABO-9 (artichoke) significantly reduced FN1 expression in both the cell types. Next, we evaluated the effect of fractions of these 2 extracts on the mRNA expression of FN1 and other extracellular matrix components, such as COL1A1, VCAN, and INHBA, in leiomyoma and myometrial cells. We found that ABO-2 (hop) and ABO-9 (artichoke) as well as their fractions, ABO-AR-2016-015 (fraction of ABO-2) and ABO-AR-2014-168 (fraction of ABO-9), reduced the mRNA expression of FN1, COL1A1, VCAN, and INHBA in primary leiomyoma cells. In primary myometrial cells, the mRNA expression of FN1, COL1A1, VCAN, and INHBA was not greatly affected. CONCLUSION(S): These results suggest that the hop and artichoke extracts possess antifibrotic properties and support additional evaluation using in vivo models.

Quercetin and indole-3-carbinol inhibit extracellular matrix expression in human primary uterine leiomyoma cells.

RESEARCH QUESTION: What is the effect of quercetin and indole-3-carbinol (I3C) on extracellular matrix expression, cell migration and proliferation in human myometrial and uterine leiomyoma cells. DESIGN: Myometrial and leiomyoma cells were treated with quercetin or I3C at different concentrations (10 µg/ml; 50 µg/ml; 100 µg/ml; and 250 µg/ml) for 48 h to measure mRNA and protein expressions of extracellular matrix (collagen 1A1, fibronectin and versican), as well as cell migration and the proliferation rate. RESULTS: Quercetin decreased mRNA levels of collagen 1A1 in myometrial (P < 0.0001) and leiomyoma cells (P < 0.0001). Quercetin reduced mRNA and protein levels of fibronectin in myometrial cells (P < 0.05) and fibronectin protein in leiomyoma cells (P < 0.05). I3C reduced collagen 1A1 mRNA levels in myometrial (P < 0.05) and leiomyoma cells at higher dose (P < 0.05). The protein levels of fibronectin were also reduced in both myometrial and leiomyoma cells with highest dose of I3C (P < 0.05), although mRNA levels were not affected in leiomyoma cells. Neither quercetin nor I3C treatment altered versican mRNA levels in both cell types. A significant reduction of the migration of both myometrial and leiomyoma cells in response to quercetin was observed (P < 0.05) and I3C (P < 0.05 for myometrial and P < 0.01 for leiomyoma cells) treatment. Both quercetin and I3C significantly reduced myometrial cell proliferation (P < 0.05). CONCLUSIONS: The in-vitro anti-fibrotic, anti-migratory and anti-proliferative effects of quercetin and I3C form the scientific basis for developing new therapeutic, preventive agents, or both, for uterine leiomyomas.

Autophagy up-regulation by ulipristal acetate as a novel target mechanism in the treatment of uterine leiomyoma: an in vitro study.

OBJECTIVE: To assess the effect of ulipristal acetate (UPA) on the autophagic process of uterine leiomyoma cells. DESIGN: In vitro study in primary cultures of leiomyoma and myometrial cells isolated from biopsy specimen, and gene expression evaluation in biopsy material. SETTING: Cellular pathology laboratory. PATIENT(S): Premenopausal women (without hormonal treatment) undergoing myomectomy or hysterectomy for symptomatic leiomyomas. INTERVENTION(S): Surgical specimens collected from uterine leiomyomas and matched normal myometria. MAIN OUTCOME MEASURE(S): After treatment of myometrial and leiomyoma cells with UPA, autophagy was evaluated by Western blot analysis of the typical biochemical markers, LC3-II, LC3-II:LC3-I ratio, and p62/SQSTM1. The expression level of Atg7 and Atg4D proteins was also assessed by Western blot. RESULT(S): The increase of LC3-II protein, LC3-II:LC3-I ratio, and p62/SQSTM1 protein indicates that UPA treatment up-regulates the autophagic response in leiomyoma cells, whereas these markers were almost unchanged in myometrial cells. Consistently, an increased level of Atg7 and Atg4D proteins was observed only in UPA-treated leiomyoma cells. The autophagic machinery is put into motion selectively in these cells, despite that the basal messenger RNA levels of LC3, SQSTM1, and ATG7 in leiomyoma biopsy specimen were not significantly different from those found in normal myometrial biopsy material. CONCLUSION(S): In vitro UPA treatment stimulates the autophagic response selectively in leiomyoma cells, which adds a novel indication for the clinical use of this selective P receptor (PR) modulator. Autophagy up-regulation may potentially contribute to the leiomyoma shrinkage occurring in UPA-treated patients and warrants further study.

Increased expression of neurogenic factors in uterine fibroids.

STUDY QUESTION: Are selective markers for the neuronal differentiation such as microtubule-associated protein 2 (MAP-2) and synaptophysin (SYP) as well as the nerve growth factor (NGF) expressed by fibroids, myometrium and eutopic endometrium? SUMMARY ANSWER: Neuronal markers NGF, MAP-2 and SYP are highly expressed in fibroids compared with matched myometrium, and this neurogenic pathway is upregulated by tumor necrosis factor (TNF) alpha in cultured smooth muscle cells (SMCs). WHAT IS KNOWN ALREADY: Uterine fibroids or leiomyomas are the most common benign tumors, accounting for approximately one-third of hysterectomies. The present trend is to improve the medical treatment avoiding surgery, also for fertility sparing; hence, the pathogenic mechanisms are investigated, aiming to develop new therapeutic strategy. STUDY DESIGN, SIZE, DURATION: This laboratory-based case-control study is focused on fibroids and myometrial specimens obtained between 2015 and 2017 from 15 women of reproductive age at the proliferative phase of the menstrual cycle. Leiomyomas, matched myometrium and endometrium from each woman were analyzed. Control endometrium was obtained from women undergoing surgery for ovarian cyst (n = 15). PARTICIPANTS/MATERIALS, SETTING, METHODS: qRT-PCR, western blotting and immunostaining were applied to evaluate the expression of neurogenic markers; the effects of TNF on NGF, MAP-2 and SYP expression in cultured SMCs from leiomyomas and matched myometrium were analyzed. MAIN RESULTS AND THE ROLE OF CHANCE: qRT-PCR analyses using tissues from clinical patients showed that the levels of NGF, MAP-2 and SYP mRNA were significantly higher in uterine leiomyomas compared with their matched myometrium (P < 0.05), whereas only NGF was significantly increased in eutopic endometrium compared with healthy endometrium. In primary SMCs, isolated from fibroids or from the adjacent myometrium, NGF, MAP-2 and SYP mRNA expression were significantly increased by TNF treatment (P < 0.05). Finally, human endometrial stromal cells prepared from the endometrium of patients affected by uterine fibroids display higher TNF expression (P < 0.001). LIMITATIONS, REASONS FOR CAUTION: qRT-PCR analysis and immunofluorescence validation are robust methods demonstrating a clear upregulation of neurogenic factors in leiomyomas, even though additional studies are needed to establish a correlation between increased neuronal gene expression and degree of pain, as well as the involvement of inflammation mediators in the development of the neurogenic unhinge. Therefore, more in vivo studies are needed to confirm the results achieved from primary cultured SMCs. WIDER IMPLICATIONS OF THE FINDINGS: The increased expression of neurogenic factors in uterine fibroids and endometrium may contribute to explain the painful stimuli. Accordingly, these neurogenic pathways may represent potential therapeutic avenues to treat the fibroid-related disorders. STUDY FUNDING/COMPETING INTEREST(S): This study was supported by research grants from the University of Siena. The authors declare no conflict of interest. TRIAL REGISTRATION NUMBER: N/A.

Advanced 3D Imaging of Uterine Leiomyoma's Morphology by Propagation-based Phase-Contrast Microtomography.

Uterine leiomyoma is the most common benign smooth muscle tumor in women pelvis, originating from the myometrium. It is caused by a disorder of fibrosis, with a large production and disruption of extracellular matrix (ECM). Medical treatments are still very limited and no preventative therapies have been developed. We supposed that synchrotron-based phase-contrast microtomography (PhC-microCT) may be an appropriate tool to assess the 3D morphology of uterine leiomyoma, without the use of any contrast agent. We used this technique to perform the imaging and the quantitative morphometric analysis of healthy myometrium and pathologic leiomyomas. The quantitative morphometric analysis of collagen bundles was coupled to the Roschger approach. This method, previously only used to evaluate mineralized bone density distribution, was applied here to study the fibrosis mass density distribution in healthy and pathologic biopsies from two patients. This protocol was shown to be powerful in studying uterine leiomyomas, detecting also small signs of the ECM alteration. This is of paramount importance not only for the follow-up of the present study, i.e. the investigation of different compounds and their possible therapeutic benefits, but also because it offers new methodologic possibilities for future studies of the ECM in soft tissues of different body districts.

Romina: A powerful strawberry with in vitro efficacy against uterine leiomyoma cells.

Uterine leiom yomas are benign tumors highly prevalent in reproductive women. In thecurrent study, initially, we aimed to screen five different strawberry cultivars (Alba, Clery, Portola, Tecla, and Romina) to identify efficient cultivars in terms of phytochemical characterization and biological properties by measuring phenolic and anthocyanin content as well as antioxidant capacity, and by measuring apoptotic rate and reactive oxygen species (ROS) production in uterine leiomyoma cells. Next, we focused on the most efficient ones, cultivar Alba (A) and Romina (R) as well as Romina anthocyanin (RA) fraction for their ability to regulate oxidative phosphorylation (oxygen consumption rate [OCR]) glycolysis (extracellular acidification rate [ECAR]), and also fibrosis. Leiomyoma and myometrial cells were treated with a methanolic extract of A and R (250 µg/ml) or with RA (50 µg/ml) for 48 hr to measure OCR and ECAR, as well as gene expression associated with fibrosis. In the leiomyoma cells, RA was more effective in inducing apoptosis and increasing intracellular ROS levels, followed by R and A. In myometrial cells, all strawberry treatments increased the cellular viability and decreased ROS concentrations. Leiomyoma cells showed also a significant decrease in ECAR, especially after RA treatment, while OCR was slightly increased in both myometrial and leiomyoma cells. R and RA treatment significantly decreased collagen 1A1, fibronectin, versican, and activin A messenger RNA expression in leiomyoma cells. In conclusion, this study suggests that Romina, or its anthocyanin fraction, can be developed as a therapeutic and/or preventive agent for uterine leiomyomas, confirming the healthy effects exerted by these fruits and their bioactive compounds.

Activin A in Mammalian Physiology.

Activins are dimeric glycoproteins belonging to the transforming growth factor beta superfamily and resulting from the assembly of two beta subunits, which may also be combined with alpha subunits to form inhibins. Activins were discovered in 1986 following the isolation of inhibins from porcine follicular fluid, and were characterized as ovarian hormones that stimulate follicle stimulating hormone (FSH) release by the pituitary gland. In particular, activin A was shown to be the isoform of greater physiological importance in humans. The current understanding of activin A surpasses the reproductive system and allows its classification as a hormone, a growth factor, and a cytokine. In more than 30 yr of intense research, activin A was localized in female and male reproductive organs but also in other organs and systems as diverse as the brain, liver, lung, bone, and gut. Moreover, its roles include embryonic differentiation, trophoblast invasion of the uterine wall in early pregnancy, and fetal/neonate brain protection in hypoxic conditions. It is now recognized that activin A overexpression may be either cytostatic or mitogenic, depending on the cell type, with important implications for tumor biology. Activin A also regulates bone formation and regeneration, enhances joint inflammation in rheumatoid arthritis, and triggers pathogenic mechanisms in the respiratory system. In this 30-yr review, we analyze the evidence for physiological roles of activin A and the potential use of activin agonists and antagonists as therapeutic agents.

Omega-3 fatty acids modulate the lipid profile, membrane architecture, and gene expression of leiomyoma cells.

Uterine leiomyomas (fibroids or myomas) are the most common benign tumors of premenopausal women and new medical treatments are needed. This study aimed to determine the effects of omega-3 fatty acids on the lipid profile, membrane architecture and gene expression patterns of extracellular matrix components (collagen1A1, fibronectin, versican, or activin A), mechanical signaling (integrin ß1, FAK, and AKAP13), sterol regulatory molecules (ABCG1, ABCA1, CAV1, and SREBF2), and mitochondrial enzyme (CYP11A1) in myometrial and leiomyoma cells. Myometrial tissues had a higher amount of arachidonic acid than leiomyoma tissues while leiomyoma tissues had a higher level of linoleic acid than myometrial tissues. Treatment of primary myometrial and leiomyoma cells with eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA) reduced the monounsaturated fatty acid (MUFA) content and increased the polyunsaturated fatty acid (PUFA) content in both cell types. Myometrial and leiomyoma cell membranes were in the liquid-crystalline phase, but EPA- and DHA-treated cells had decreased membrane fluidity. While we found no changes in the mRNA expression of ECM components, EPA and DHA treatment reduced levels of ABCG1, ABCA1, and AKAP13 in both cell types. EPA and DHA also reduced FAK and CYP11A1 expression in myometrial cells. The ability of omega-3 fatty acids to remodel membrane architecture and downregulate the expression of genes involved in mechanical signaling and lipid accumulation in leiomyoma cells offers to further investigate this compound as preventive and/or therapeutic option.

Extracellular matrix in uterine leiomyoma pathogenesis: a potential target for future therapeutics.

BACKGROUND: Uterine leiomyoma (also known as fibroid or myoma) is the most common benign tumor of the uterus found in women of reproductive age. It is not usually fatal but can produce serious clinical symptoms, including excessive uterine bleeding, pelvic pain or pressure, infertility and pregnancy complications. Due to lack of effective medical treatments surgery has been a definitive choice for the management of this tumor. OBJECTIVE AND RATIONALE: Extracellular matrix (ECM) accumulation and remodeling are thought to be crucial for fibrotic diseases such as uterine leiomyoma. Indeed, ECM plays important role in forming the bulk structure of leiomyoma, and the ECM-rich rigid structure within these tumors is thought to be a cause of abnormal bleeding and pelvic pain. Therefore, a better understanding of ECM accumulation and remodeling is critical for developing new therapeutics for uterine leiomyoma. SEARCH METHODS: PubMed and Google Scholar were searched for all original and review articles/book chapters related to ECM and medical treatments of uterine leiomyoma published in English until May 2017. OUTCOMES: This review discusses the involvement of ECM in leiomyoma pathogenesis as well as current and future medical treatments that target ECM directly or indirectly. Uterine leiomyoma is characterized by elevated levels of collagens, fibronectin, laminins and proteoglycans. They can induce the mechanotransduction process, such as activation of the integrin-Rho/p38 MAPK/ERK pathway, resulting in cellular responses that are involved in pathogenesis and altered bidirectional signaling between leiomyoma cells and the ECM. ECM accumulation is affected by growth factors (TGF-ß, activin-A and PDGF), cytokines (TNF-α), steroid hormones (estrogen and progesterone) and microRNAs (miR-29 family, miR-200c and miR-93/106b). Among these, TGF-ßs (1 and 3) and activin-A have been suggested as key players in the accumulation of excessive ECM (fibrosis) in leiomyoma. The presence of elevated levels of ECM and myofibroblasts in leiomyoma supports the fibrotic character of these tumors. Interestingly, ECM may serve as a reservoir of profibrotic growth factors and enhance their activity by increasing their stability and extending their duration of signaling. At present, several classes of compounds, including gonadotropin-releasing hormone (GnRH) agonist (leuprolide acetate), GnRH antagonist (cetrorelix acetate), selective progesterone receptor modulators (ulipristate acetate and asoprisnil), antiprogestin (mifepristone) and natural compounds like vitamin D and resveratrol have been studied as medical treatments that target ECM in uterine leiomyoma. WIDER IMPLICATIONS: Although several types of drugs (mostly antiproliferative agents) are available for leiomyoma treatment, none of them were introduced specifically as antifibrotic agents. In light of its critical role in the process of fibrosis in leiomyoma, we propose that ECM should be considered as a crucial target for future therapeutics. Thus, the introduction of drugs that are specifically antifibrotic could be a good solution to control abnormal leiomyoma growth and associated clinical symptoms. The antifibrotic compounds can be introduced based on their ability to regulate ECM components and their receptors, as well as growth factors, cytokines, steroid hormones and their corresponding receptors and intracellular signaling pathways, as well as microRNAs, involved in ECM production in leiomyoma.