Dual inhibition of AKT and ERK1/2 pathways restores the expression of progesterone Receptor-B in endometriotic lesions through epigenetic mechanisms

Endometriosis is an estrogen-dependent and progesterone-resistant gynecological inflammatory disease of reproductive-age women. Progesterone resistance, loss of progesterone receptor -B (PR-B) in the stromal cells of the endometrium, is one of the hallmarks of endometriosis and a major contributing factor for infertility in endometriosis patients. Loss of PR-B in the stromal cells of the endometriotic lesions poses resistance to the success of progesterone-based therapy. The working hypothesis is that PR-B is hypermethylated and epigenetically silenced, and inhibition of AKT and ERK1/2 pathways will decrease the hypermethylation, reverse the epigenetic silencing, and restore the expression of PR-B via DNA methylation and histone modification mechanisms in the endometriotic lesions. The objectives are to (i) determine the effects of dual inhibition of AKT and ERK1/2 pathways on the expression of PR-B and DNA methylation and histone modification protein machinery in the endometriotic lesions and (ii) identify the underlying epigenetic mechanisms of PR-B restoration in the endometriotic lesions. The results indicate that dual inhibition of AKT and ERK1/2 pathways decreases the hypermethylation, reverses the epigenetic silencing, and restores the expression of PR-B via DNA methylation and H3K9 and H3K27 methylation mechanisms in the endometriotic lesions or endometriotic stromal cells of human origin. These results support the novel concept that restored expression of PR-B in the endometriotic lesions and endometrium may improve the clinical outcome of progesterone therapy in endometriosis patients.

Cytokine and chemokine profiles in women with endometriosis, polycystic ovary syndrome, and unexplained infertility

Numerous factors (including immunological, congenital, hormonal, and morphological disorders) can lead to infertility. In this regard, 3 specific diseases associated with infertility are discussed in this review study (i.e., polycystic ovary syndrome [PCOS], endometriosis [EMS], and unexplained infertility [UI]). PCOS is a common endocrine disorder characterized by chronic low-grade inflammation, and EMS is a benign disease characterized by the presence of ectopic endometrial tissue. UI refers to couples who are unable to conceive for no known reason. Conception and pregnancy are significantly affected by the immune system; in this regard, chemokines and cytokines play important roles in the regulation of immune responses. Patients with PCOS, EMS, and UI have altered cytokine and chemokine profiles, suggesting that dysregulation of these molecules may contribute to infertility in these conditions. Accordingly, the issue of infertility is addressed in this review study, a condition that affects approximately 16% of couples worldwide.

The mysterious association between adiponectin and endometriosis

Adiponectin is a pleiotropic cytokine predominantly derived from adipose tissue. In addition to its role in regulating energy metabolism, adiponectin may also be related to estrogen-dependent diseases, and many studies have confirmed its involvement in mediating diverse biological processes, including apoptosis, autophagy, inflammation, angiogenesis, and fibrosis, all of which are related to the pathogenesis of endometriosis. Although many researchers have reported low levels of adiponectin in patients with endometriosis and suggested that it may serve as a protective factor against the development of the disease. Therefore, the purpose of this review was to provide an up-to-date summary of the roles of adiponectin and its downstream cytokines and signaling pathways in the aforementioned biological processes. Further systematic studies on the molecular and cellular mechanisms of action of adiponectin may provide novel insights into the pathophysiology of endometriosis as well as potential therapeutic targets.

Immune pathway through endometriosis to ovarian cancer

Endometriosis is an estrogen-dependent inflammatory disease, defined by the presence of functional endometrial tissue outside of the uterine cavity. This disease is one of the main gynecological diseases, affecting around 10%-15% women and girls of reproductive age, being a common gynecologic disorder. Although endometriosis is a benign disease, it shares several characteristics with invasive cancer. Studies support that it has been linked with an increased chance of developing endometrial ovarian cancer, representing an earlier stage of neoplastic processes. This is particularly true for women with clear cell carcinoma, low-grade serous carcinoma and endometrioid. However, the carcinogenic pathways between both pathologies remain poorly understood. Current studies suggest a connection between endometriosis and endometriosis-associated ovarian cancers (EAOCs) via pathways associated with oxidative stress, inflammation, and hyperestrogenism. This article aims to review current data on the molecular events linked to the development of EAOCs from endometriosis, specifically focusing on the complex relationship between the immune response to endometriosis and cancer, including the molecular mechanisms and their ramifications. Examining recent developments in immunotherapy and their potential to boost the effectiveness of future treatments.

Vanillin prevents the growth of endometriotic lesions through anti-inflammatory and antioxidant pathways in a mouse model

Endometriosis is an estrogen-dependent chronic inflammatory gynecological disease defined by the presence of endometrial glands and mesenchyme outside the uterine cavity, named ectopic endometrium. Recent studies showed that endometriosis is associated with hormone imbalance, inflammation and oxidative stress. As the main component of vanilla bean extract, vanillin is widely used as a flavoring agent in the food, pharmaceutical, and cosmetic industries. It is known for its anti-inflammatory, antibacterial, and antitumor properties, but its therapeutic efficacy in endometriosis has not been studied. In this study, we evaluated the roles of vanillin in this disease using an induced endometriotic mouse model. The results showed that vanillin significantly inhibited the growth of endometrial lesions. Compared with the control group, the weight and volume of lesions were reduced considerably in the vanillin-treated group, showing its fantastic ability to inhibit cell proliferation and promote apoptosis. In addition, in the treatment group, mRNA expression of the pro-inflammatory cytokines Tnfa, Infg, Il1b, and Il6 was reduced, the number of macrophages and neutrophils was decreased, and the NF-κB signaling pathway was inhibited, indicating that vanillin suppressed the inflammatory response in the ectopic endometrium. Besides, we found that the intensity of tissue reactive oxygen species (ROS) was significantly lower, and mitochondrial complex IV expression was reduced in the vanillin-treated group. Meanwhile, treatment of the immortalized human endometriotic epithelial cell line (11Z) with vanillin resulted in the downregulation of cyclin genes that drive the cell proliferation process, inhibited cell proliferation, promoted apoptosis, and downregulated the expression of LPS-induced inflammatory cytokines. Most importantly, our data showed that the vanillin treatment had only minimal effects on the eutopic endometrium with respect to the pregnancy process, indicating its safety to be used in treating endometriosis in adults. In conclusion, our data suggest that vanillin has potential therapeutic properties for endometriosis as a regulatory molecule of cell proliferation, apoptosis, inflammation, and oxidative stress.

Low-Nutrient Environment-Induced Changes in Inflammation, Cell Proliferation, and PGC-1α Expression in Stromal Cells with Ovarian Endometriosis

Although nutrient status plays an important role in cell metabolism, its significance in endometriosis is obscure. Herein, we investigated the effects of a low-nutrient microenvironment on endometriosis. Stromal cells (SCs) from ovarian endometrioma (OESCs) or normal endometrium without endometriosis (NESCs) were isolated and cultured. A low-nutrient microenvironment was replicated by replacing the culture medium with Hank's balanced salt solution. OESC and NESC proliferation under the low-nutrient condition was measured. The expression of exacerbating factors in endometriosis under the low-nutrient condition was examined at the mRNA and protein levels. OESCs showed higher proliferation than NESCs under the low-nutrient condition. In OESCs, the low-nutrient condition upregulated the mRNA expression of vascular endothelial growth factor (VEGF), interleukin-6 and -8, aromatase, Bcl-2, and peroxisome proliferator-activated receptor-gamma coactivator-1α (PGC-1α) and downregulated that of BAX and induced transcription of PI.3, PII, and exon II. Western blotting revealed elevated VEGF and PGC-1α expression under the low-nutrient condition in OESCs. These changes coincided with the elevated expression of PGC-1α, which was reduced at the mRNA level upon nutrient status rescue. Endometriosis is exacerbated by altered angiogenesis, inflammation, anti-apoptosis, and local estrogen production while trying to survive under a low-nutrient microenvironment; it may be attributed to PGC-1α-mediated metabolic mechanisms.

Effect of active vitamin D on proliferation, cell cycle and apoptosis in endometriotic stromal cells

RESEARCH QUESTION

What is the effect of vitamin D3 (1,25(OH)₂D₃) on proliferation, cell cycle and apoptosis of endometrial stromal cells (ESC) in endometriotic patients?

DESIGN

ESC isolated from 10 women with endometriosis and 10 healthy controls were treated with 1,25(OH)₂D₃. The proliferation of control endometrial stromal cells (CESC), eutopic endometrial stromal cells (EuESC) and ectopic endometrial stromal cells (EESC) was analysed 72 h after the treatment using methyl thiazolyl tetrazolium assay. Propidium iodide staining and flow cytometry were used to determine the cell cycle distribution in ESC. Annexin V/propidium iodide double staining was used to evaluate apoptosis in ESC.

RESULTS

In the presence of oestrogen, 1,25(OH)₂D₃ treatment inhibited the proliferation of ESC from all three origins (P = 0.009 for CESC, P = 0.005 for EuESC and P < 0.001 for EESC). The percentage of S phase cells in EESC was higher than in EuESC and CESC (P = 0.002 and P = 0.001, respectively). The percentage of S phase cells in EuESC was higher than in CESC (P = 0.005). The percentage of G1 phase cells in EESC was lower than that of EuESC and CESC (P = 0.003 and P = 0.002, respectively) and the percentage of G1 phase cells in EuESC was lower than that of CESC (P = 0.007). Moreover, 1,25(OH)₂D₃ inhibited cell cycle regardless of cell type (P = 0.002 in EESC, P = 0.001 in EuESC and P = 0.014 in CESC), but in the absence of oestrogen, inhibited cell cycle only in EuESC (P = 0.012).

CONCLUSIONS

Although 1,25(OH)₂D₃ increased apoptotic and necrotic cells and decreased live cells in the EuESC and EESC, it did not affect apoptosis in CESC and only increased necrotic cells. These findings indicate that 1,25(OH)₂D₃ potentially has a growth-inhibiting and pro-apoptotic effect on ESC from endometriotic patients.

Molecular and Clinical Insights on the Complex Interaction between Oxidative Stress, Apoptosis, and Endobiota in the Pathogenesis of Endometriosis

Endometriosis (EMS) remains, to date, an intriguing and debilitating gynecological disorder that possesses a multifactorial substrate. Recent studies with the objective of elucidating its etiology highlighted the antagonistic effect of EMS on a multiple of processes involved in homeostasis. Although the current oxidative biomarkers clearly reveal the consequences induced by EMS, its implication in the associated inflammatory reactions could be much more complex. Besides the overproduction of reactive oxygen species (ROS) that leads to an exacerbated oxidative response, it also changes the normal expression of several pro-inflammatory modulators, reflected by the fluctuating activity of several pro- and anti-apoptotic mediators whose expression is impaired. In light of this topic, several studies elucidate the involvement of apoptosis in EMS, being brought controversial findings, even reports with no significant change. Further, some authors reported an abnormal expression of multiple genes that are crucial for the overall functionality of the female reproductive system. Cumulatively, it seems that the subsequent oxidative imbalance and apoptosis process impairment could further disrupt the normal removal of unnecessary biological products. Based on all gathered evidence, we could argue that the related stress state could determine human endobiota impairment, which could further participate in the inflammatory and main antioxidant enzyme changes occurring in EMS. Moreover, a correlation between endobiota integrity, inflammation, and oxidative stress (OS) was suggested in relation to the possible predisposition to pathogen determined infections.

Multi-omics analysis reveals the interaction between the complement system and the coagulation cascade in the development of endometriosis

Endometriosis (EMS) is a disease that shows immune dysfunction and chronic inflammation characteristics, suggesting a role of complement system in its pathophysiology. To find out the hub genes and pathways involved in the pathogenesis of EMs, three raw microarray datasets were recruited from the Gene Expression Omnibus database (GEO). Then, a series of bioinformatics technologies including gene ontology (GO), Hallmark pathway enrichment, protein-protein interaction (PPI) network and gene co-expression correlation analysis were performed to identify hub genes. The hub genes were further verified by the Real-time quantitative polymerase chain reaction (RT-PCR) and Western Blot (WB). We identified 129 differentially expressed genes (DEGs) in EMs, of which 78 were up-regulated and 51 were down-regulated. Through GO functional enrichment analysis, we found that the DEGs are mainly enriched in cell adhesion, extracellular matrix remodeling, chemokine regulation, angiogenesis regulation, epithelial cell proliferation, et al. In Hallmark pathway enrichment analysis, coagulation pathway showed great significance and the terms in which included the central complement factors. Moreover, the genes were dominating in PPI network. Combined co-expression analysis with experimental verification, we found that the up-regulated expression of complement (C1S, C1QA, C1R, and C3) was positively related to tissue factor (TF) in EMs. In this study, we discovered the over expression complement and the positive correlation between complement and TF in EMs, which suggested that interaction of complement and coagulation system may play a role within the pathophysiology of EMS.

Polyphenols as a Diet Therapy Concept for Endometriosis-Current Opinion and Future Perspectives

Endometriosis represents an often painful, estrogen-dependent gynecological disorder, defined by the existence of endometrial glands and stroma exterior to the uterine cavity. The disease provides a wide range of symptoms and affects women’s quality of life and reproductive functions. Despite research efforts and extensive investigations, this disease’s pathogenesis and molecular basis remain unclear. Conventional endometriosis treatment implies surgical resection, hormonal therapies, and treatment with nonsteroidal anti-inflammatory drugs, but their efficacy is currently limited due to many side effects. Therefore, exploring complementary and alternative therapy strategies, minimizing the current treatments’ adverse effects, is needed. Plants are sources of bioactive compounds that demonstrate broad-spectrum health-promoting effects and interact with molecular targets associated with endometriosis, such as cell proliferation, apoptosis, invasiveness, inflammation, oxidative stress, and angiogenesis. Anti-endometriotic properties are exhibited mainly by polyphenols, which can exert a potent phytoestrogen effect, modulating estrogen activity. The available evidence derived from preclinical research and several clinical studies indicates that natural biologically active compounds represent promising candidates for developing novel strategies in endometriosis management. The purpose of this review is to provide a comprehensive overview of polyphenols and their properties valuable for natural treatment strategy by interacting with different cellular and molecular targets involved in endometriosis progression.

Brassica Bioactives Could Ameliorate the Chronic Inflammatory Condition of Endometriosis

Endometriosis is a chronic, inflammatory, hormone-dependent disease characterized by histological lesions produced by the presence of endometrial tissue outside the uterine cavity. Despite the fact that an estimated 176 million women are affected worldwide by this gynecological disorder, risk factors that cause endometriosis have not been properly defined and current treatments are not efficient. Although the interaction between diet and human health has been the focus of many studies, little information about the correlation of foods and their bioactive derivates with endometriosis is available. In this framework, Brassica crops have emerged as potential candidates for ameliorating the chronic inflammatory condition of endometriosis, due to their abundant content of health-promoting compounds such as glucosinolates and their hydrolysis products, isothiocyanates. Several inflammation-related signaling pathways have been included among the known targets of isothiocyanates, but those involving aquaporin water channels have an important role in endometriosis. Therefore, the aim of this review is to highlight the promising effects of the phytochemicals present in Brassica spp. as major candidates for inclusion in a dietary approach aiming to improve the inflammatory condition of women affected with endometriosis. This review points out the potential roles of glucosinolates and isothiocyanates from Brassicas as anti-inflammatory compounds, which might contribute to a reduction in endometriosis symptoms. In view of these promising results, further investigation of the effect of glucosinolates on chronic inflammatory diseases, either as diet coadjuvants or as therapeutic molecules, should be performed. In addition, we highlight the involvement of aquaporins in the maintenance of immune homeostasis. In brief, glucosinolates and the modulation of cellular water by aquaporins could shed light on new approaches to improve the quality of life for women with endometriosis.

Phytochemical characteristics from Phaleria macrocarpa and its inhibitory activity on the peritoneal damage of endometriosis

Background

Endometriois represents a gynecological disease that still becomes an issue in community. Phaleria macrocarpa is a plant native to Indonesia that contains an antioxidant substance, which may serve as apoptotic modulator and useful for angiogenesis.

Objective

This study aims to evaluate the effects of flavonoid isolates from P. macrocarpa (PM) on the development of granulomas, apoptosis, proliferation, and angiogenesis of the disease.

Material and methods

Total thirty mice (Mus musculus) were categorized into six groups, including the normal group (without any treatment), EMT (endometriosis) group, and EMT group treated with PM flavonoid isolates. Identification of the active compounds of P. macrocarpa was done using LC-HRMS. Measurement of granuloma scores and vascular density was done histologically. Apoptosis and proliferation analysis was performed by immunohistochemical techniques.

Results

There was an increase in granulomas, proliferation, and apoptosis in the peritoneal tissues of the endometriosis model. This change can be normalized by extract of P. macrocarpa.

Conclusion

We concluded that the flavonoid isolates from P. macrocarpa can suppress the growth of endometriosis lesions through normalization of proliferation and apoptosis. Thus, the P. macrocarpa flavonoid can be used as an alternative to inhibit the development of endometriosis.

Evaluation of apoptosis and angiogenesis in ectopic and eutopic stromal cells of patients with endometriosis compared to non-endometriotic controls

Background

Endometriosis is a chronic, painful, and inflammatory disease characterized by extra-uterine growth of endometrial tissues. Increased angiogenesis and resistance to apoptosis have been suggested to be involved in pathogenesis and development of endometriosis. The objective of this study was to examine apoptosis potential and angiogenesis contribution of eutopic (EuESCs) and ectopic (EESCs) endometrial stromal cells in patients with endometriosis compared to endometrial stromal cells from non-endometriotic controls (CESCs).

Methods

Stromal cells were isolated by enzymatic digestion of ectopic (n = 11) and eutopic (n = 17) endometrial tissues from laparoscopically-confirmed endometriotic patients. Endometrial stromal cells of 15 non-endometriotic patients served as control. Following cell characterization by immunofluorescent staining and flow cytometry using a panel of antibodies, the total RNA was isolated from the cultured cells, and analyzed for the expression of genes involved in apoptosis (Bcl-2, Bcl-xL, Bax, and caspase-3) and angiogenesis [vascular endothelial growth factor-A (VEGF-A) and hepatocyte growth factor (HGF)] by Real-time PCR.

Results

Significantly higher gene expression levels of Bcl-2 and Bcl-xL were found in EESCs compared with EuESCs and CESCs (p < 0.01). The gene expression of Bax in EESCs, EuESCs, and CESCs was not statistically significant. Furthermore, EuESCs exhibited a significantly lower caspase-3 gene expression compared with CESCs (p < 0.01) or EESCs (p < 0.05). Regarding angiogenesis, VEGF-A gene expression in EESCs (p < 0.001) and EuESCs (p < 0.05) were significantly higher compared with those of CESCs. EESCs exhibited a significantly higher HGF gene expression compared with EuESCs (p < 0.05).

Conclusions

These findings suggest reduced propensity to apoptosis and increased angiogenesis potential of EESCs, which may be involved in pathogenesis of endometriosis.

The Pathogenesis of Endometriosis: Molecular and Cell Biology Insights

The etiopathogenesis of endometriosis is a multifactorial process resulting in a heterogeneous disease. Considering that endometriosis etiology and pathogenesis are still far from being fully elucidated, the current review aims to offer a comprehensive summary of the available evidence. We performed a narrative review synthesizing the findings of the English literature retrieved from computerized databases from inception to June 2019, using the Medical Subject Headings (MeSH) unique ID term "Endometriosis" (ID:D004715) with "Etiology" (ID:Q000209), "Immunology" (ID:Q000276), "Genetics" (ID:D005823) and "Epigenesis, Genetic" (ID:D044127). Endometriosis may origin from Müllerian or non-Müllerian stem cells including those from the endometrial basal layer, Müllerian remnants, bone marrow, or the peritoneum. The innate ability of endometrial stem cells to regenerate cyclically seems to play a key role, as well as the dysregulated hormonal pathways. The presence of such cells in the peritoneal cavity and what leads to the development of endometriosis is a complex process with a large number of interconnected factors, potentially both inherited and acquired. Genetic predisposition is complex and related to the combined action of several genes with limited influence. The epigenetic mechanisms control many of the processes involved in the immunologic, immunohistochemical, histological, and biological aberrations that characterize the eutopic and ectopic endometrium in affected patients. However, what triggers such alterations is not clear and may be both genetically and epigenetically inherited, or it may be acquired by the particular combination of several elements such as the persistent peritoneal menstrual reflux as well as exogenous factors. The heterogeneity of endometriosis and the different contexts in which it develops suggest that a single etiopathogenetic model is not sufficient to explain its complex pathobiology.

Dual inhibition of ERK1/2 and AKT pathways is required to suppress the growth and survival of endometriotic cells and lesions

Endometriosis is an estrogen-dependent and progesterone-resistant gynecological inflammatory disease of reproductive-age women. Current hormonal therapies targeting estrogen can be prescribed only for a short time. It indicates a need for non-hormonal therapy. ERK1/2 and AKT pathways control several intracellular signaling molecules that control growth and survival of cells. Objectives of the present study are to determine the dual inhibitory effects of ERK1/2 and AKT pathways: (i) on proliferation, survival, and apoptosis of human endometrioitc epithelial cells and stromal cells in vitro; (ii) on growth and survival of endometrioitc lesions in vivo in xenograft mouse model of endometriosis of human origin; and (iii) establish the associated ERK1/2 and AKT downstream intracellular signaling modules in the pathogenesis of endometriosis. Our results indicated that combined inhibition of ERK1/2 and AKT pathways highly decreased the growth and survival of human endometriotic epithelial cells and stromal cells in vitro and suppressed the growth of endometriotic lesions in vivo compared to inhibition of either ERK1/2 or AKT pathway individually. This cause-effect is associated with dysregulated intracellular signaling modules associated with cell cycle, cell survival, and cell apoptosis pathways. Collectively, our results indicate that dual inhibition of ERK1/2 and AKT pathways could emerge as potential non-hormonal therapy for the treatment of endometriosis.

Impact of a Chinese Medicinal Formula, Xiao Liu Fang, on the "3A" Ability of Endometrial Stromal Cells in Patients with Endometriosis

The pathogenesis of endometriosis (EMS) is complicated, and treatment results are unsatisfactory. It has become the focus of gynecological research. Analysis targeting the pathogenesis of EMS is the key to providing more effective treatments. In recent years, the superiority of traditional Chinese medicine in treating EMS has been highlighted, so we investigated the impact of a Chinese medicinal formula (Xiao Liu Fang) on the “3A” ability, in situ, of ectopic endometrial stromal cells in patients with EMS. Primary endometrial stromal cells were isolated using a modified net filtration method, cultured, and identified in different groups. Endometrial cell attachment was measured using the methyl thiazolyl tetrazolium (MTT) colorimetric assay, cell aggression was detected by the transwell cell-invasion assay, and angiogenesis was defined by evaluating the mRNA concentrations of intercellular cell adhesion molecule 1 (ICAM-1), cyclooxygenase 2 (COX-2), matrix metallo peptidase 9 (MMP-9), and vascular endothelial growth factor (VEGF). Attachment, aggression, and angiogenesis (AAA) plays an important role in EMS, and a high dose of the Xiao Liu Fang extract can be used for the treatment of EMS owing to its inhibition of the AAA of endometrial stromal cells. Therefore, in-depth studies targeting the effective mechanisms and targets of traditional Chinese medicine (TCM) are of great significance for the prevention and treatment of EMS.

Protective role of propofol in endometriosis and its mechanism

Endometriosis (EM) is a common benign gynecological disorder. The present study aimed to investigate the potential role of propofol, a commonly used intravenous anesthetic agent, in the pathogenesis of EM. The EM cell line CRL-7566 was used in the present study. CRL-7566 cells were first treated with various concentrations of propofol (0, 1, 5 or 10 µg/ml) for specific duration, and the cell viability and apoptotic rate were determined by performing an MTT and a flow cytometric cell apoptosis assay, respectively. The protein and mRNA levels of cell proliferation- and apoptosis-associated genes were detected by western blot and reverse-transcription quantitative polymerase chain reaction, respectively. The results demonstrated that propofol inhibited CRL-7566 cell proliferation in a dose- and time-dependent manner. CRL-7566 cell apoptosis was dose-dependently induced by propofol treatment. In addition, propofol treatment significantly increased the levels of forkhead box (FOX)O1, FOXO3, Bim, pro-caspase-3, active caspase-3, p53 and p21. In conclusion, the present study suggested that propofol inhibited the proliferation and induced apoptosis of EM cells via inducing the expression/activation of multiple associated genes/proteins, indicating a protective role of propofol in EM.

Endocannabinoids modulate apoptosis in endometriosis and adenomyosis

Adenomyosis that is a form of endometriosis is the growth of ectopic endometrial tissue within the muscular wall of the uterus (myometrium), which may cause dysmenorrhea and infertility. Endocannabinoid mediated apoptotic mechanisms of endometriosis and adenomyosis are not known. We hypothesized that the down regulation of endocannabinoid receptors and/or alteration in their regulatory enzymes may have a direct role in the pathogenesis of endometriosis and adenomyosis through apoptosis. Endocannabinoid receptors CB1 and CB2, their synthesizing and catabolizing enzymes (FAAH, NAPE-PLD, DAGL, MAGL) and the apoptotic indexes were immunohistochemically assessed in endometriotic and adenomyotic tissues. Findings were compared to normal endometrium and myometrium. Endometrial adenocarcinoma (Ishikawa) and ovarian endometriosis cyst wall stromal (CRL-7566) cell lines were furthermore cultured with or without cannabinoid receptor agonists. The IC50 value for CB1 and CB2 receptor agonists was quantified. Cannabinoid agonists on cell death were investigated by Annexin-V/Propidium iodide labeling with flow cytometry. CB1 and CB2 receptor levels decreased in endometriotic and adenomyotic tissues compared to the control group (p=0,001 and p=0,001). FAAH, NAPE-PLD, MAGL and DAGL enzyme levels decreased in endometriotic and adenomyotic tissues compared to control (p=0,001, p=0,001, p=0,001 and p=0,002 respectively). Apoptotic cell indexes both in endometriotic and adenomyotic tissues also decreased significantly, compared to the control group (p=0,001 and p=0,001). CB1 and CB2 receptor agonist mediated dose dependent fast anti-proliferative and pro-apoptotic effects were detected in Ishikawa and ovarian endometriosis cyst wall stromal cell lines (CRL-7566). Endocannabinoids are suggested to increase apoptosis mechanisms in endometriosis and adenomyosis. CB1 and CB2 antagonists can be considered as potential medical therapeutic agents for endometriosis and adenomyosis.

Regulation of apoptotic pathways during endometriosis: from the molecular basis to the future perspectives

PURPOSE

Endometriosis is defined as the presence of endometrial-like endometrial cells, glands and stroma outside the uterus, causing a strong inflammatory-like microenvironment in the affected tissue. This may provoke a breakdown in the peritoneal cavity homeostasis, with the consequent processes of immune alteration, documented by peripheral mononuclear cells recruitment and secretion of inflammatory cytokines in early phases and of angiogenic and fibrogenic cytokines in the late stages of the disease. Considering the pivotal role of interaction between immune and endometriotic cells, in this paper, we aim to shed light about the role of apoptosis pathways in modulating the fine-regulated peritoneal microenvironment during endometriosis.

METHODS

Narrative overview, synthesizing the findings of literature retrieved from searches of computerized databases.

RESULTS

In normal conditions, endometriotic cells, refluxed through the fallopian tubes into the peritoneal cavity, should be attacked and removed by phagocytes and NK cells. During endometriosis, the breakdown of peritoneal homeostasis causes the failure of scavenging mechanisms, allowing the survival of endometriotic cells. The consequent so-called "immunoescaping" of endometriotic cells could be due, at least in part, to the reduction of apoptotic-mediated pathways previously described.

CONCLUSION

Considering the large amount of evidence retrieved from in vitro as well as in vivo models, the reduced apoptosis of endometriotic cells together with the increased apoptosis of peritoneal fluid mononuclear cells may address the peritoneal homeostasis to a permissive environment for the progression of the disease.

DNA repair gene XRCC1 and XRCC4 variations and risk of endometriosis: an association study

BACKGROUND

Endometriosis is a polygenic and multifactorial disease. DNA damage plays a major role in mutagenesis, carcinogenesis and aging and is usually repaired by the action of several DNA repair enzymes. We investigated the association of the common variations of the DNA repair genes XRCC1 and XRCC4 with susceptibility to endometriosis in an Iranian population.

METHODS

In total, 160 patients with endometriosis (stages I-IV) and 174 healthy women were included in this case-control study. Genotyping of XRCC1 codon 399 as well as of XRCC4 -1394T/G, codon 247 and intron 3 insertion/deletion variations was performed using restriction fragment length polymorphism analysis of PCR-amplified fragments.

RESULTS

The XRCC4 -1394TG genotype frequency was significantly lower (p = 0.005) in the patients (9.4%) than in the controls (21.1%). The frequency of the -1394G allele was significantly lower (p < 0.0001) in the patients (6.6%) than in the controls (19.0%). There were no statistically significant differences in the genotype and allele frequencies of the XRCC1 codon 399, XRCC4 codon 247 and XRCC4 intron 3 insertion/deletion polymorphisms between the cases and controls.

CONCLUSIONS

The XRCC4 -1394T/G polymorphism was associated with susceptibility to endometriosis in an Iranian population.

Behavior of tumor necrosis factor-α and tumor necrosis factor receptor 1/tumor necrosis factor receptor 2 system in mononuclear cells recovered from peritoneal fluid of women with endometriosis at different stages

During endometriosis, a breakdown occurs in endometrial and peritoneal homeostasis caused by cytokine-induced cell proliferation and dysregulation of apoptosis. We studied tumor necrosis factor (TNF)-α, TNF receptor (TNFR) 1, and TNFR2 gene expression at both messenger RNA (mRNA) and protein levels in peritoneal fluid (PF) mononuclear cells (PFMCs), the percentages of these cells bearing the same markers, and soluble TNF-α (sTNF-α) values in PF of 80 women with endometriosis. We found that TNFR1 mRNA and protein levels, the percentages of TNFR1-bearing PFMCs, and sTNF-α values decreased from minimal to severe stages of the disease. Instead, TNF-α and TNFR2 mRNA and protein levels, the percentages of membrane TNF-α (mTNF-α)- and TNFR2-bearing PFMCs increased as the disease worsened. These data allow us to hypothesize that, in early stages, the high percentages of TNFR1-bearing PFMCs and the high levels of sTNF-α could address signal toward complex I pathway, favoring the inflammatory response. With the worsening of the disease, the low percentages of TNFR1-bearing PFMCs are probably due to decreased TNFR1 mRNA transcription and protein translation rate. In early stages (minimal and mild), the percentages of both TNFR2- and mTNF-α-bearing PFMCs are so low, due to decreased mRNA transcription and protein translation rate, that subsequent cellular events may depend minimally by this interaction. The high levels of sTNF-α may be rerouted to bind TNFR1. In contrast, in the moderate and severe stages, the high percentages of TNFR2-bearing PFMCs may be saturated by high percentages of mTNF-α-bearing PFMCs, triggering death process. So, in endometriosis, each component of the TNF-α/TNFRs system may trigger opposite cellular fate.

The dynamics of nuclear receptors and nuclear receptor coregulators in the pathogenesis of endometriosis

BACKGROUND

Endometriosis is defined as the colonization and growth of endometrial tissue at anatomic sites outside the uterine cavity. Up to 15% of reproductive-aged women in the USA suffer from painful symptoms of endometriosis, such as infertility, pelvic pain, menstrual cycle abnormalities and increased risk of certain cancers. However, many of the current clinical treatments for endometriosis are not sufficiently effective and yield unacceptable side effects. There is clearly an urgent need to identify new molecular mechanisms that critically underpin the initiation and progression of endometriosis in order to develop more specific and effective therapeutics which lack the side effects of current therapies. The aim of this review is to discuss how nuclear receptors (NRs) and their coregulators promote the progression of endometriosis. Understanding the pathogenic molecular mechanisms for the genesis and maintenance of endometriosis as modulated by NRs and coregulators can reveal new therapeutic targets for alternative endometriosis treatments.

METHODS

This review was prepared using published gene expression microarray data sets obtained from patients with endometriosis and published literature on NRs and their coregulators that deal with endometriosis progression. Using the above observations, our current understanding of how NRs and NR coregulators are involved in the progression of endometriosis is summarized.

RESULTS

Aberrant levels of NRs and NR coregulators in ectopic endometriosis lesions are associated with the progression of endometriosis. As an example, endometriotic cell-specific alterations in gene expression are correlated with a differential methylation status of the genome compared with the normal endometrium. These differential epigenetic regulations can generate favorable cell-specific NR and coregulator milieus for endometriosis progression. Genetic alterations, such as single nucleotide polymorphisms and insertion/deletion polymorphisms of NR and coregulator genes, are frequently detected in ectopic lesions compared with the normal endometrium. These genetic variations impart new molecular properties to NRs and coregulators to increase their capacity to stimulate progression of endometriosis. Finally, post-translational modifications of NR coregulators, such as proteolytic processing, generate endometriosis-specific isoforms. Compared with the unmodified coregulators, these coregulator isoforms have unique functions that enhance the pathogenesis of endometriosis.

CONCLUSIONS

Epigenetic/genetic variations and posttranslational modifications of NRs and coregulators alter their original function so that they become potent 'drivers' of endometriosis progression.

Role of iron overload-induced macrophage apoptosis in the pathogenesis of peritoneal endometriosis

This article presents an overview of the involvement of iron overload-induced nitric oxide (NO) overproduction in apoptosis of peritoneal macrophages of women with endometriosis. We have postulated that the peritoneal iron overload originated from retrograde menstruation or bleeding lesions in the ectopic endometrium, which may contribute to the development of endometriosis by a wide range of mechanisms, including oxidative damage and chronic inflammation. Excessive NO production may also be associated with impaired clearance of endometrial cells by macrophages, which promotes cell growth in the peritoneal cavity. Therefore, further research of the mechanisms and consequences of macrophage apoptosis in endometriosis helps discover novel therapeutic strategies that are designed to prevent progression of endometriosis.

Regression of experimentally induced endometriosis with a new selective cyclooxygenase-2 enzyme inhibitor

BACKGROUND

Cyclooxygenase-2 (COX-2) levels increase in women with endometriosis. COX-2, via increasing prostaglandin E2, contributes to an increase in vascular endothelial growth factor. In this way, COX-2 may contribute to the progression and continuity of endometriosis. We investigated the effect of dexketoprofen trometamol, a new selective COX-2 enzyme inhibitor, on experimentally induced endometriotic cysts.

METHODS

Experimental endometriotic cysts were created in 60 adult female Wistar albino rats. The rats were randomized to 2 equal groups, a control (group Con) and a dexketoprofen (group Dex) group. Six weeks later, cyst volumes were measured as in vivo (volume 1). Following volume 1 measurement, for 4 weeks group Con received 0.1 ml distilled water; group Dex received 0.375 mg dexketoprofen trometamol/0.1 ml distilled water, intramuscularly, twice a day. At the end of administration, the cyst volumes were remeasured (volume 2), and the cysts totally excised and weighed. Glandular (GT) and stromal tissues (ST) and natural killer (NK) cell contents in the cyst wall were scored.

RESULTS

NK cell content and volume 1 were not different between the 2 groups. Volume 2, cyst weight, and GT and ST contents in group Dex were significantly lower than those in group Con.

CONCLUSION

Dexketoprofen trometamol significantly reduced the development of experimentally induced endometriotic cysts both macroscopically and microscopically.

Interplay between Misplaced Müllerian-Derived Stem Cells and Peritoneal Immune Dysregulation in the Pathogenesis of Endometriosis

In the genetic regulation of Müllerian structures development, a key role is played by Hoxa and Wnt clusters, because they lead the transcription of different genes according to the different phases of the organogenesis, addressing correctly cell-to-cell interactions, allowing, finally, the physiologic morphogenesis. Accumulating evidence is suggesting that dysregulation of Wnt and/or Hox genes may affect cell migration during organogenesis and differentiation of Müllerian structures of the female reproductive tract, with possible dislocation and dissemination of primordial endometrial stem cells in ectopic regions, which have high plasticity to differentiation. We hypothesize that during postpubertal age, under the influence of different stimuli, these misplaced and quiescent ectopic endometrial cells could acquire new phenotype, biological functions, and immunogenicity. So, these kinds of cells may differentiate, specializing in epithelium, glands, and stroma to form a functional ectopic endometrial tissue. This may provoke a breakdown in the peritoneal cavity homeostasis, with the consequent processes of immune alteration, documented by peripheral mononuclear cells recruitment and secretion of inflammatory cytokines in early phases and of angiogenic and fibrogenic cytokines in the late stages of the disease.

Association between two single nucleotide polymorphisms of PDCD6 gene and increased endometriosis risk

Programmed cell death 6 (PDCD6), a calcium binding protein of the penta EF-hand protein family, and its receptors are involved in regulation of apoptosis pathways. To evaluate the relationship between genetic polymorphisms of PDCD6 gene and endometriosis (ED) risk, we investigated the association of two single nucleotide polymorphisms (SNPs) of PDCD6 gene (rs4957014 and rs3756712) in 220 endometriosis patients and 386 unrelated healthy controls. The genotypes of these two SNPs were determined by using polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) and DNA sequencing methods. Significantly increased endometriosis risk was observed to be associated with G allele of rs4957014 locus (OR=1.31, 95% CI=1.03-1.69). We have also observed increased ED risk was statistically associated with rs4957014 polymorphism in a dominant model (OR=1.52, 95% CI=1.09-2.13). Although no association has been found between ED risk and the allele frequencies of rs3756712 locus (a marginal P=0.066, OR=1.27, 95% CI=0.98-1.65), but in a dominant model, increased endometriosis risk was significantly associated with rs3756712 polymorphism (OR=1.54, 95% CI=1.11-2.17). In conclusion, the current study indicates that PDCD6 gene may be a new susceptibility gene to endometriosis.

Imbalance in cytokines from interleukin-1 family - role in pathogenesis of endometriosis

PROBLEM

To assess whether interleukin (IL)-1beta, IL-18 and interleukin-1 converting enzyme (ICE) are involved in the pathogenesis of endometriosis.

METHOD OF STUDY

Peritoneal fluid (PF) was obtained from 85 women with and without endometriosis. Peritoneal macrophages were cultured and the culture media collected. IL-1beta, IL-18 and ICE levels were measured by the enzyme-linked immunosorbent assay (ELISA).

RESULTS

Levels of IL-1beta and ICE in PF of women with endometriosis were higher than those in the control group. However, PF level of IL-18 was significantly lower in the study group than in the controls. Higher secretion of IL-1beta by peritoneal macrophages and lower IL-18 and ICE in endometriosis patients than in control were observed. Following lipopolysaccharide (LPS) stimulation, the macrophages secreted more IL-1beta, IL-18 and ICE in all groups.

CONCLUSIONS

The results pointed to impairment of the secretion of the IL-1 cytokine family in endometriosis. Invalid IL-1beta and IL-18 maturation by ICE may be an important pathogenic factor in endometriosis.

Gonadotrophin-releasing hormone analogues and endometriosis: current strategies and new insights

BACKGROUND

Endometriosis is an estrogen-dependent chronic inflammatory disease affecting 5% to 10% of women in reproductive age and has been reported also in adolescents. Its main clinical presentations are chronic pelvic pain and infertility.

OBJECTIVE

To provide a comprehensive review of the recently published data concerning the mechanism of action of gonadotrophin-releasing hormone analogues (GnRHas) as well as to analyze their role in the management of endometriosis-associated pain and infertility in addition to its value in adolescent cases. Furthermore, to provide practical recommendations and new insights based on the best available information.

METHODS

Systematic search was performed of the Cochrane Library and Medical Literature Analysis and Retrieval System Online database looking for the different trials, reviews and various guidelines relating to GnRHas usage in the management of endometriosis-associated pain, infertility and in adolescent cases.

RESULTS

From a pathophysiological perspective, there is a growing scientific evidence that GnRHas exert its therapeutic effects by their classical pituitary downregulation and via a direct effect on the endometrial cells themselves. Accordingly, they represent an important medical option for the management of different aspects of this enigmatic disease.

CONCLUSION

GnRHas have a valuable strategic role in treatment of endometriosis-associated pain and infertility as well as in adolescents above 16 years.

Apoptosis resistance in endometriosis

INTRODUCTION

In a cytological analysis of endometriotic lesions neither granulocytes nor cytotoxic T-cells appear in an appreciable number. Based on this observation we aimed to know, whether programmed cell death plays an essential role in the destruction of dystopic endometrium. Disturbances of the physiological mechanisms of apoptosis, a persistence of endometrial tissue could explain the disease. Another aspect of this consideration is the proliferation competence of the dystopic mucous membrane.

METHODS

Endometriotic lesions of 15 patients were examined through a combined measurement of apoptosis activity with the TUNEL technique (terminal deoxyribosyltransferase mediated dUTP Nick End Labeling) and the proliferation activity (with the help of the Ki-67-Antigens using the monoclonal antibody Ki-S5).

RESULTS

Twelve out of 15 women studied showed a positive apoptotic activity of 3-47% with a proliferation activity of 2-25% of epithelial cells. Therefore we concluded that the persistence of dystopic endometrium requires proliferative epithelial cells from middle to lower endometrial layers.

CONCLUSION

A dystopia misalignment of the epithelia of the upper layers of the functionalism can be rapidly eliminated by apoptotic procedures.

Involvement of estrogen receptor-related receptors in human ovarian endometriosis

OBJECTIVE

To determine whether decreased estrogen receptor alpha (ER-α) expression in endometriotic lesions could be balanced by an increased expression of estrogen receptor-related receptors (ERRs). To evaluate whether ERR-α expression is influenced by hormonal change in fertile and menopausal women.

DESIGN

Prospective controlled study.

SETTING

University Hospital, Department of Gynecology.

PATIENT(S)

Twenty-five women: 20 women of reproductive age with (n = 10) and without (control; n = 10) endometriosis and 5 menopausal women.

INTERVENTION(S)

Real-time polymerase chain reaction (qPCR). Immunohistochemistry.

MAIN OUTCOME MEASURE(S)

The ER and ERR expression levels were studied by reverse transcriptase-qPCR, ELISA, and immunohistochemistry using endometriotic and normal endometrial tissues. The ERR-α protein distribution was performed by immunohistochemistry in fertile and menopausal women.

RESULT(S)

Increased levels of ER-β were associated with ER-α, ERR-α, and ERR-γ reductions in ectopic tissue but not in eutopic and normal endometria. Similar levels of ERR-β were found in women with and without endometriosis. The ERR-α expression was similar in proliferative and secretory endometrial samples, whereas a down-regulation of this receptor was found in atrophic tissue.

CONCLUSION(S)

Our data confirm the up-regulation of ER-β as the principal receptor involved in the progression of human endometriosis. In addition, we found that ERR-α seems to be unresponsive to hormonal changes during the menstrual cycle.

Relationship between adenomyosis and uterine polyps

OBJECTIVE

To evaluate whether adenomyosis is associated with uterine polyps.

STUDY DESIGN

To perform an ethical human study, we planned a large retrospective observational study covering the entire patient population of the ULSS 17-Veneto district who underwent resectoscopy in 2007 and 2008 (959 patients). We enrolled all the patients underwent resectoscopy with resection of uterine polyps, with resection of myomas, with endometrial ablations by slicing, and with endometrial biopsies in both the presence and absence of hysteroscopically visible lesions. The diagnosis of adenomyosis was made by pathological examination of tissue specimens obtained using a resectoscope loop. Multivariate logistic regression was performed to determine if adenomyosis was one of the various risk factors for the presence and number of uterine polyps. Statistical Package for the Social Sciences (SPSS 16.0) was employed, and p≤0.05 was the minimum for significance.

RESULTS

Age (p=0.005), adenomyosis (p=0.013), high fasting glucose levels (p=0.004), and hypertension (p=0.045) were significantly associated with endometrial polyps. The presence of multiple endometrial polyps seemed to be associated with the presence of adenomyosis (p=0.016). The presence of cervical polyps was significantly associated only with presence of adenomyosis (p=0.002). The presence of multiple cervical polyps did not seem to be influenced by any of the variables considered.

CONCLUSIONS

The results clearly demonstrate an association between adenomyosis and uterine polyps. The pathogenetic role of adenomyosis in the development of polyps should therefore be investigated further.

Cordycepin (3'-deoxyadenosine), an inhibitor of mRNA polyadenylation, suppresses proliferation and activates apoptosis in human epithelial endometriotic cells in vitro

BACKGROUND/AIMS

Endometriosis is a benign but chronic disorder associated with pelvic pain and infertility. Enhanced proliferation and reduced apoptosis susceptibility are characteristics of endometriosis. Cordycepin is a poly(A) polymerase inhibitor. It induces shortening of poly(A) tails, leading to destabilization of mRNAs and finally to proliferation inhibition and cell death in normal and tumor cells. The potential of cordycepin to block proliferation and survival of 11z human immortalized epithelial endometriotic cells was determined.

METHODS

11z cell cultures were treated with cordycepin. Cordycepin-induced inhibition of proliferation and alterations in protein expression and protein phosphorylation were determined by the methyl thiazolyl tetrazolium assay and immunoblot analysis, respectively.

RESULTS

Cordycepin induced the rapid and significant upregulation of the cell cycle progression inhibitor p21 and the downregulation of the cell cycle progression promoter cyclin D(1), finally leading to the inhibition of the proliferation of 11z human epithelial endometriotic cells. Cordycepin reduced the phosphorylation of the p38 mitogen-activated protein kinase and the retinoblastoma protein. It also activated caspase-dependent, intrinsic apoptosis, as documented by the proteolytic cleavage of the caspase-9, caspase-3 and the poly(ADP ribose) polymerase 1 precursor.

CONCLUSION

The mRNA polyadenylation inhibitor cordycepin inhibits proliferation and survival of endometriotic cells.