Endometriotic epithelial cells induce MMPs expression in endometrial stromal cells via an NFkappaB-dependent pathway

Metformin enhances epithelial cell growth inhibition via the protein kinase-insulin-like growth factor binding protein-1 pathway

BACKGROUND

Abnormal stromal-epithelial cell communication is a pathogenic mechanism in endometriosis, and metformin can modulate it. Insulin-like growth factor binding protein-1 (IGFBP1) plays a role in endometriosis, but the exact mechanism is unknown. IGFBP1 is reportedly a downstream target of metformin in some diseases. We aimed to investigate the role of IGFBP1 in endometriosis development, whether it is associated with abnormal communication, and whether metformin affects IGFBP1 expression.

METHODS

Patients who underwent surgical treatment for endometriosis or other diseases were enrolled. Ten patients with ovarian-type endometriosis and eight patients each who underwent surgical treatment for other lesions with or without endometriosis were selected, and their tissues taken for cell proliferation, western blotting, polymerase chain reaction, and knockdown experiments.

RESULTS

Ectopic and eutopic stromal cells (EcSCs and EuSCs) lost their ability to inhibit epithelial cell proliferation, and IGFBP1 expression was downregulated in both groups of stromal cells compared to that in normal stromal cells (NSCs; 1.09 vs. 0.25, p = .0002 1.09 vs. 0.57, p = .0029). In an EcSC IGFBP1 overexpression model, the ability of EcSCs to inhibit epithelial cell proliferation was enhanced (EdU positivity decreased from 38% to 25%, p = .0001). Furthermore, adenosine 5'-monophosphate-activated protein kinase (AMPK) phosphorylation was downregulated in EcSCs and EuSCs compared to that in NSCs (0.99 vs. 0.42, p = .0006/0.99 vs. 0.57, p = 0.0032). Treatment of EcSCs with metformin increased AMPK phosphorylation (0.47 vs. 1.04, p = .0107) while upregulating IGFBP1 expression (0.69 vs. 1.01, p = .0164), whereas pre-treatment with an AMPK phosphorylation inhibitor abrogated metformin-induced IGFBP1 upregulation.

CONCLUSIONS

IGFBP1 mediates aberrant stromal-epithelial communication in endometriosis. Metformin can upregulate IGFBP1 expression in EcSCs by activating AMPK, and upregulated IGFBP1 enhances the inhibition of epithelial cell proliferation. IGFBP1 is expected to be a therapeutic target for endometriosis.

Promotion of BST2 expression by the transcription factor IRF6 affects the progression of endometriosis

Background

Endometriosis (EM) is a benign, multifactorial, immune-mediated inflammatory disease that is characterized by persistent activation of the NF-κB signaling pathway and some features of malignancies, such as proliferation and lymphangiogenesis. To date, the pathogenesis of EM is still unclear. In this study, we investigated whether BST2 plays a role in the development of EM.

Methods

Bioinformatic analysis was performed with data from public databases to identify potential candidate targets for drug treatment. Experiments were conducted at the cell, tissue, and mouse EM model levels to characterize the aberrant expression patterns, molecular mechanisms, biological behaviors of endometriosis as well as treatment outcomes.

Results

BST2 was significantly upregulated in ectopic endometrial tissues and cells compared with control samples. Functional studies indicated that BST2 promoted proliferation, migration, and lymphangiogenesis and inhibited apoptosis in vitro and in vivo. The transcription factor (TF) IRF6 induced high BST2 expression by directly binding the BST2 promoter. The underlying mechanism by which BST2 functions in EM was closely related to the canonical NF-κB signaling pathway. New lymphatic vessels may serve as a channel for the infiltration of immune cells into the endometriotic microenvironment; these immune cells further produce the proinflammatory cytokine IL-1β, which in turn further activates the NF-κB pathway to promote lymphangiogenesis in endometriosis.

Conclusion

Taken together, our findings provide novel insight into the mechanism by which BST2 participates in a feedback loop with the NF-κB signaling pathway and reveal a novel biomarker and potential therapeutic target for endometriosis.

An Update on the Multifaceted Role of NF-kappaB in Endometriosis

Endometriosis remains a common but challenging gynecological disease among reproductive-aged women with an unclear pathogenesis and limited therapeutic options. Numerous pieces of evidence suggest that NF-κB signaling, a major regulator of inflammatory responses, is overactive in endometriotic lesions and contributes to the onset, progression, and recurrence of endometriosis. Several factors, such as estrogen, progesterone, oxidative stress, and noncoding RNAs, can regulate NF-κB signaling in endometriosis. In the present review, we discuss the mechanisms by which these factors regulate NF-κB during endometriosis progression and provide an update on the role of NF-κB in affecting endometriotic cells, peritoneal macrophages (PMs) as well as endometriosis-related symptoms, such as pain and infertility. Furthermore, the preclinical drugs for blocking NF-κB signaling in endometriosis are summarized, including plant-derived medicines, NF-κB inhibitors, other known drugs, and the potential anti-NF-κB drugs predicted through the Drug-Gene Interaction Database. The present review discusses most of the studies concerning the multifaceted role of NF-κB signaling in endometriosis and provides a summary of NF-κB-targeted treatment in detail.

The estrogen-regulated lncRNA H19/miR-216a-5p axis alters stromal cell invasion and migration via ACTA2 in endometriosis

Fibrotic tissue may contribute to the origin of some endometriosis-related symptoms, such as chronic pelvic pain and infertility. Alterations in the H19/miR-216a-5p/ACTA2 pathway may mediate the regulation of eutopic endometrial stromal cell (euESC) invasion and migration and may represent a potential mechanism underlying fibrous tissue formation or fibrosis in women with endometriosis. In this study, we aimed to determine the expression of H19 and ACTA2 in endometrial tissues of women with endometriosis. Two groups of 23 infertile women with endometriosis and 23 matched infertile women without endometriosis were investigated. Primary cultured cells of endometrial tissues were analyzed using RT-PCR and western blotting (WB) to determine expression of H19 and ACTA2. 5-Ethyl-2'-deoxyuridine, CCK8 and Transwell assays were used to study the functions of H19 and ACTA2. Human embryonic kidney 293 cells were used for luciferase assays to study miR-216a-5p binding sites with H19 and ACTA2. We found that H19 and ACTA2 levels were significantly higher in endometriosis euESCs than in control euESCs (P < 0.05) and were positively correlated in endometriosis euESCs. Luciferase assays indicated that H19 regulates ACTA2 expression via competition for inhibitory miR-216a-5p binding sites. Our results indicate that alterations in the estrogen/H19/miR-216a-5p/ACTA2 pathway regulated endometriosis euESC invasion and migration. Downregulation of H19 or ACTA2 inhibited endometriosis euESC invasion and migration; however, estrogen promoted endometriosis euESC invasion and migration via H19. The main limitation of our study was that experiments were conducted in vitro and further in vivo studies are required in the future. However, our study showed that primary cultured cells represented endometriosis cells more clearly than cell lines.

Therapeutic Approaches of Resveratrol on Endometriosis via Anti-Inflammatory and Anti-Angiogenic Pathways

Endometriosis represents a severe gynecological pathology, defined by implantation of endometrial glands and stroma outside the uterine cavity. This pathology affects almost 15% of women during reproductive age and has a wide range of consequences. In affected women, infertility has a 30% rate of prevalence and endometriosis implants increase the risk of ovarian cancer. Despite long periods of studies and investigations, the etiology and pathogenesis of this disease still remain not fully understood. Initially, endometriosis was related to retrograde menstruation, but new theories have been launched, suggesting that chronic inflammation can influence the development of endometriosis because inflammatory mediators have been identified elevated in patients with endometriosis, specifically in the peritoneal fluid. The importance of dietary phytochemicals and their effect on different inflammatory diseases have been highlighted, and nowadays more and more studies are focused on the analysis of nutraceuticals. Resveratrol is a phytoestrogen, a natural polyphenolic compound with antiproliferative and anti-inflammatory actions, found in many dietary sources such as grapes, wine, peanuts, soy, berries, and stilbenes. Resveratrol possesses a significant anti-inflammatory effect via inhibition of prostaglandin synthesis and it has been proved that resveratrol can exhibit apoptosis-inducing activities. From the studies reviewed in this paper, it is clear that the anti-inflammatory effect of this natural compound can contribute to the prevention of endometriosis, this phenolic compound now being considered a new innovative drug in the prevention and treatment of this disease.

Melatonin inhibits 17β-estradiol-induced migration, invasion and epithelial-mesenchymal transition in normal and endometriotic endometrial epithelial cells

BACKGROUND

Melatonin is a potential therapeutic agent for endometriosis, but its molecular mechanism is unclear. Here, we investigated the effect of melatonin on the epithelial-mesenchymal transition (EMT) in endometriotic endometrial epithelial cells and explored the pathway that might be involved.

METHODS

This hospital-based study included 60 women of reproductive age using the endometrium for immunohistochemistry, 6 women of reproductive age undergoing bilateral tubal ligation and 6 patients with endometriosis for isolation of endometrial epithelial cells or subsequent analysis, respectively. We examined the expression of Notch1/Numb signaling and EMT markers by immunohistochemistry analysis and western blot analysis, the invasion and migration of endometrial epithelial cells by transwell assays, and the cell proliferation by CCK8 assays.

RESULTS

Compared with normal endometrium, the endometriotic eutopic endometrium showed increased expression of Notch1, Slug, Snail, and N-cadherin, and decreased expression of E-cadherin and Numb. Melatonin or Notch inhibition by specific inhibitor blocked 17β-estradiol-induced cell proliferation, invasion, migration and EMT-related markers in both normal and endometriotic epithelial cells.

CONCLUSIONS

Our data suggest that aberrant expression of Notch1/Numb signaling and the EMT is present in endometriotic endometrium. Melatonin may block 17β-estradiol-induced migration, invasion and EMT in normal and endometriotic epithelial cells by upregulating Numb expression and decreasing the activity of the Notch signaling pathway.

Investigational drugs for the treatment of endometriosis, an update on recent developments

INTRODUCTION

Endometriosis is a hormone-dependent benign chronic disease that requires a chronic medical therapy. Although currently available drugs are efficacious in treating endometriosis-related pain, some women experience partial or no improvement. Moreover, the recurrence of symptoms is expected after discontinuation of the therapies. Currently, new drugs are under intense clinical investigation for the treatment of endometriosis.

AREAS COVERED

This review aims to offer the reader a complete and updated overview on new investigational drugs and early molecular targets for the treatment of endometriosis. The authors describe the pre-clinical and clinical development of these agents.

EXPERT OPINION

Among the drugs under investigation, late clinical trials on gonadotropin-releasing hormone antagonists (GnRH-ant) showed the most promising results for the treatment of endometriosis. Aromatase inhibitors (AIs) are efficacious in treating endometriosis related pain symptoms but they cause significant adverse effects that limit their long-term use. New targets have been identified to produce drugs for the treatment of endometriosis, but the majority of these new compounds have only been investigated in laboratory studies or early clinical trials. Thus, further clinical research is required in order to elucidate their efficacy and safety in human.

Syndecan-1 Acts as an Important Regulator of CXCL1 Expression and Cellular Interaction of Human Endometrial Stromal and Trophoblast Cells

Successful implantation of the embryo into the human receptive endometrium is substantial for the establishment of a healthy pregnancy. This study focusses on the role of Syndecan-1 at the embryo-maternal interface, the multitasking coreceptor influencing ligand concentration, release and receptor presentation, and cellular morphology. CXC motif ligand 1, being involved in chemotaxis and angiogenesis during implantation, is of special interest as a ligand of Syndecan-1. Human endometrial stromal cells with and without Syndecan-1 knock-down were decidualized and treated with specific inhibitors to evaluate signaling pathways regulating CXC ligand 1 expression. Western blot analyses of MAPK and Wnt members were performed, followed by analysis of spheroid interactions between human endometrial cells and extravillous trophoblast cells. By mimicking embryo contact using IL-1β, we showed less ERK and c-Jun activation by depletion of Syndecan-1 and less Frizzled 4 production as part of the canonical Wnt pathway. Additionally, more beta-catenin was phosphorylated and therefore degraded after depletion of Syndecan-1. Secretion of CXC motif ligand 1 depends on MEK-1 with respect to Syndecan-1. Regarding the interaction of endometrial and trophoblast cells, the spheroid center-to-center distances were smaller after depletion of Syndecan-1. Therefore, Syndecan-1 seems to affect signaling processes relevant to signaling and intercellular interaction at the trophoblast-decidual interface.

Metformin regulates stromal-epithelial cells communication via Wnt2/β-catenin signaling in endometriosis

In previous studies, we found that endometriotic stromal cells lose the ability to regulate cell survival signaling in endometriotic epithelial cells. Here, we invested the effect of Metformin on the stromal-epithelial cells crosstalk in endometriosis and explored the pathway that might be involved. We found that ectopic endometriotic stromal cells (ESC) expressed and secreted higher Wnt2 protein compared with normal endometrial stromal cells (NSC). Conditioned medium (CM) from ESC supplemented with Wnt2 antibody significantly inhibited the growth of normal endometrial epithelial cells (NEC), while CM from ESC per se showed no significant effect on the growth of NEC. Metformin decreased the expression and secretion of Wnt2 in ESC. CM from Metformin-pretreated ESC significantly inhibited the growth of NEC. In conclusion, Wnt2/β-catenin signaling was involved in stromal-epithelial cells interaction in endometriosis. Metformin might regulate the stroma-epithelium communication via Wnt2-mediated signaling in endometriosis.

Tissue-engineered endometrial model for the study of cell-cell interactions

Endometrial stromal and epithelial cell cross talk is known to influence many of the dynamic changes that occur during the menstrual cycle. We modified our previous model and embedded telomerase-immortalized human endometrial stromal cells and Ishikawa adenocarcinoma epithelial cells in a collagen-Matrigel hydrogel to create a tissue-engineered model of the endometrium. Comparisons of single and cocultured cells examined communication between endometrial stromal and epithelial cells, which were cultured with 0 or 10 nmol/L 17β estradiol; conditioned medium was used to look at the production of paracrine factors. Using this model, we were able to identify the changes in interleukin 6 (IL-6) and active matrix metalloproteinase 2, which appear to be due to paracrine signaling and differences in transforming growth factor β1 (TGF-β1) that do not appear to be due to paracrine signaling. Moreover, IL-6, TGF-β1, and DNA content were also affected by the presence of estradiol in many of the tissues. These results indicate that paracrine and endocrine signaling are involved in human endometrial responses and support the use of coculture models to further investigate cell-cell and cell-matrix interactions.