Expression of cadherins and CD44 isoforms in human endometrium and peritoneal endometriosis

MLLT11 Regulates Endometrial Stroma Cell Adhesion, Proliferation and Survival in Ectopic Lesions of Women with Advanced Endometriosis

MLLT11 is a gene implicated in cell differentiation and the development and progression of human cancers, but whose role in the pathogenesis of endometriosis is still unknown. Using quantitative RT-PCR and immunohistochemistry, we analyzed 37 women with and 33 women without endometriosis for differences in MLLT11 expression. We found that MLLT11 is reduced in the ectopic stroma cells of women with advanced stage endometriosis compared to women without endometriosis. MLLT11 knockdown in control stroma cells resulted in the downregulation of their proliferation accompanied by G1 cell arrest and an increase in the expression of p21 and p27. Furthermore, the knockdown of MLLT11 was associated with increased apoptosis resistance to camptothecin associated with changes in BCL2/BAX signaling. Finally, MLLT11 siRNA knockdown in the control primary stroma cells led to an increase in cell adhesion associated with the transcriptional activation of ACTA2 and TGFB2. We found that the cellular phenotype of MLLT11 knockdown cells resembled the phenotype of the primary endometriosis stroma cells of the lesion, where the levels of MLLT11 are significantly reduced compared to the eutopic stroma cells of women without the disease. Overall, our results indicate that MLLT11 may be a new clinically relevant player in the pathogenesis of endometriosis.

The immunolocalization of cadherins and beta-catenin in the cervix and vagina of cycling cows

The adherens junctions (AJs) maintain the epithelial cell layers' structural integrity and barrier function. AJs also play a vital role in various biological and pathological processes. AJs perform these functions through the cadherin-catenin adhesion complex. This study investigated the presence, cell-specific localization, and temporal distribution of AJ components such as classical type I cadherins and beta-catenin in the cow cervix and vagina during the estrous cycle. Immunohistochemistry and Western blot analysis results demonstrated that beta-catenin and epithelial (E)-, neural (N)-, and placental (P)-cadherins are expressed in the cow cervix and vagina during the estrous cycle. These adhesion molecules were localized in the membrane and cytoplasm of the ciliated and non-ciliated cervical cells and the stratified vaginal epithelial cells. Positive immunostaining for P-, N-cadherin, and beta-catenin was also observed in the vascular endothelial cells of the cervical and vaginal stroma. Quantitative immunohistochemistry examinations revealed that in the cervical and vaginal epithelia, P-cadherin's optical density values (ODv) were the highest; in contrast, the N-cadherin ODv were the lowest. The ODv of P-cadherin and beta-catenin in the cervical epithelium and E-cadherin in the vagina were significantly higher in the luteal phase versus the follicular phase of the estrous cycle. Furthermore, the ODv of P-cadherin, N-cadherin, and beta-catenin in the cervix's central and peripheral epithelial regions were different during the estrous cycle. These findings indicate that classical cadherins and beta-catenin in the cervix and vagina exhibit cell- and tissue-specific expression patterns under the influence of estrogen and progesterone hormones during the estrous cycle.

Effects of Progestin on Modulation of the Expression of Biomarkers in Endometriosis

BACKGROUND

Our study aimed to examine the osteopontin (OPN) serum levels and tissue expression of CD44 and OPN in endometriosis-affected women both undergoing and not undergoing progestin treatment, and also to determine their involvement in the pathogenesis of endometriosis.

METHODS

Using an ELISA kit, we evaluated the OPN serum levels of healthy and endometriosis-affected women both undergoing and not undergoing progestin treatment. Immunohistochemical (IHC) analyses were used to assess the endometriotic tissue expressions of CD44 and OPN.

RESULTS

There were statistically significant higher OPN serum levels in the healthy control group compared to the women with endometriosis. Furthermore, there were higher OPN serum levels in the endometriosis-affected women undergoing the progestin treatment, but the difference did not reach statistical significance. In comparison to OPN, CD44 expression was significantly higher in all the endometriotic tissue glands and stroma, regardless of the patient's treatment status. Compared to the group receiving therapy, the OPN levels were higher in the endometriosis group not receiving therapy. OPN's robust cytoplasmic expression seemed to be associated with the non-treatment group.

CONCLUSION

Endometriosis, CD44, and OPN appear to be closely related. This study suggests that endometriosis that has not been treated has an immunological profile distinct to endometriosis that has received treatment.

The Comparative Invasiveness of Endometriotic Cell Lines to Breast and Endometrial Cancer Cell Lines

Endometriosis is an invasive condition that affects 10% of women (and people assigned as female at birth) worldwide. The purpose of this study was to characterize the relative invasiveness of three available endometriotic cell lines (EEC12Z, iEc-ESCs, tHESCs) to cancer cell lines (MDA-MB-231, SW1353 and EM-E6/E7/TERT) and assess whether the relative invasiveness was consistent across different invasion assays. All cell lines were subjected to transwell, spheroid drop, and spheroid-gel invasion assays, and stained for vimentin, cytokeratin, E-Cadherin and N-Cadherin to assess changes in expression. In all assays, endometriotic cell lines showed comparable invasiveness to the cancer cell lines used in this study, with no significant differences in invasiveness identified. EEC12Z cells that had invaded within the assay periods showed declines in E-Cadherin expression compared to cells that had not invaded within the assay period, without significant changes in N-Cadherin expression, which may support the hypothesis that an epithelial-to-mesenchymal transition is an influence on the invasiveness shown by this peritoneal endometriosis cell line.

Assessment of BMP7, SMAD4, and CDH1 Expression Profile and Regulatory miRNA-542-3p in Eutopic and Ectopic Endometrium of Women with Endometriosis

Alterations in the expression of numerous genes and the miRNAs that are recognized as their regulators in the endometrial cells of women with endometriosis may disrupt the intracellular signaling pathways associated with epithelial–mesenchymal transition (EMT). So far, the functional role of BMP7 in endometrial physiology has been confirmed, especially in the context of fertility, but the role of the activation of a specific mechanism operating through the BMP–SMAD–CDH1 axis in the formation of endometrial lesions remains unexplored. The aim of this study was to evaluate the expression profile of miR-542-3p and the EMT markers (BMP7, SMAD4, CDH1) in matched eutopic endometrium (EUE) and ectopic endometrium (ECE) samples from women with endometriosis in relation to healthy women. The levels of expression of the studied genes and miRNA in peripheral blood mononuclear cells (PBMCs) obtained from women diagnosed with endometriosis and those without the disease were also evaluated. Fifty-four patients (n = 54: with endometriosis—n = 29 and without endometriosis—n = 25) were included in the study. A comparative analysis of the relative mean expression values (RQ) of the studied mRNA and miRNA assessed by RT-qPCR demonstrated downregulation of BMP7, SMAD4, and CDH1 expression in ectopic lesions and upregulation in the eutopic endometrium compared with the control group. In the eutopic tissue of women with endometriosis, miR-542-3p expression was similar to that of the control but significantly lower than in endometrial lesions. We also confirmed a trend towards a negative correlation between miR-542-3p and BMP7 in ectopic tissue, and in PBMC, a significant negative correlation of miR-542-3p with further BMP signaling genes, i.e., SMAD4 and CDH1, was observed. These results indicate that the miRNA selected by us may be a potential negative regulator of BMP7-SMAD4-CDH1 signaling associated with EMT. The different patterns of BMP7, SMAD4, and CDH1 gene expression in ECE, EUE, and the control endometrium observed by us suggests the loss of the endometrial epithelium phenotype in women with endometriosis and demonstrates their involvement in the pathogenesis and pathomechanism of this disease.

Osteopontin Splicing Isoforms Contribute to Endometriotic Proliferation, Migration, and Epithelial-Mesenchymal Transition in Endometrial Epithelial Cells

Osteopontin (OPN) isoforms, including OPNb and OPNc, promote malignancy and may contribute to the pathogenesis of endometriosis, a benign disorder with multiple characteristics resembling malignant tumors. In our experiments, OPNb and OPNc were significantly overexpressed in both endometriosis and adenomyosis compared to the normal endometrium. Upregulation of CD44v and the epithelial-mesenchymal transition (EMT) process was also present in endometriotic lesions. Overexpression of OPNb and OPNc splicing variants in endometriotic cells evoked morphological changes, actin remodeling, cell proliferation, cell migration, and EMT through binding OPN ligand receptors CD44 and αvβ3, subsequently activating the PI3K and NF-ĸB pathways. We elucidated the causal role of OPN splice variants in regulating endometriotic cell growth, which may promote the development of OPN-targeted therapies for patients suffering from endometriotic disorders.

Sunitinib Reduced the Migration of Ectopic Endometrial Cells via p-VEGFR-PI3K-AKT-YBX1-Snail Signaling Pathway

Endometriosis (EMs) is one of the most common gynecological diseases, lacking effective treatment. EMs are currently being treated with small molecule targeted therapy, which has resulted in a significant reduction in patient suffering. Our previous studies have shown that sunitinib plays an obvious role in migration. Consequently, the purpose of this study is to explore the molecular mechanism by which sunitinib suppressed the ectopic endometrial migration. The ectopic endometrial cells from patients were divided into two groups: the control group and the sunitinib group. Co-IP and protein spectrum assay were employed to filtrate differential proteins between two groups, and then, our study discovered a signaling pathway, p-VEGFR-PI3K-AKT-YBX1-Snail, in the cell of EMs. To confirm this signaling pathway, VEGF165 was added to the sunitinib group to upregulate the expression of VEGFR. Next, the expression of p-VEGFR, PI3K, AKT, YBX1, and snail was measured in the control group and sunitinib group (compared with the control group: p-VEGFR, PI3K, AKT, YBX1, and snail, $\ast \ast \ast \ast P<0.0001$ ) and the VEGFR+sunitinib group (compared with the sunitinib group: p-VEGFR, PI3K, AKT, and snail, $\ast \ast \ast \ast P<0.0001$ ; YBX1, $\ast \ast \ast P<0.001$ ); finally, the outcome was as expected. In addition to in vitro experiments, we also conducted in vivo experiments in mice. In the EMs mouse model, we found sunitinib reduced the number of heterotopic foci ( $t=11.16$ , $\ast \ast \ast \ast P<0.0001$ ) and inhibited the expression of p-VEGFR, YBX1, and snail by immunofluorescence. To sum up, sunitinib exactly reduced the migration of ectopic endometrial cells with the involvement of the p-VEGFR-PI3K-AKT-YBX1-Snail signaling pathway in both in vitro and in vivo experiments. This study suggests that sunitinib presents a potential targeted drug for EMs therapy.

Clues for Improving the Pathophysiology Knowledge for Endometriosis Using Plasma Micro-RNA Expression

The pathophysiology of endometriosis remains poorly understood. The aim of the present study was to investigate functions and pathways associated with the various miRNAs differentially expressed in patients with endometriosis. Plasma samples of the 200 patients from the prospective "ENDO-miRNA" study were analyzed and all known human miRNAs were sequenced. For each miRNA, sensitivity, specificity, and ROC AUC values were calculated for the diagnosis of endometriosis. miRNAs with an AUC ≥ 0.6 were selected for further analysis. A comprehensive review of recent articles from the PubMed, Clinical Trials.gov, Cochrane Library, and Web of Science databases was performed to identify functions and pathways associated with the selected miRNAs. In total, 2633 miRNAs were found in the patients with endometriosis. Among the 57 miRNAs with an AUC ≥ 0.6: 20 had never been reported before; one (miR-124-3p) had previously been observed in endometriosis; and the remaining 36 had been reported in benign and malignant disorders. miR-124-3p is involved in ectopic endometrial cell proliferation and invasion and plays a role in the following pathways: mTOR, STAT3, PI3K/Akt, NF-κB, ERK, PLGF-ROS, FGF2-FGFR, MAPK, GSK3B/β-catenin. Most of the remaining 36 miRNAs are involved in carcinogenesis through cell proliferation, apoptosis, and invasion. The three main pathways involved are Wnt/β-catenin, PI3K/Akt, and NF-KB. Our results provide evidence of the relation between the miRNA profiles of patients with endometriosis and various signaling pathways implicated in its pathophysiology.

Identification of genes associated with susceptibility to persistent breeding-induced endometritis by RNA-sequencing of uterine cytobrush samples

This study aimed to investigate the susceptibility to persistent breeding-induced endometritis (PBIE). Cytobrush samples were collected from 81 broodmares 1-3 days before artificial insemination (AI). Susceptibility to PBIE was evaluated by the presence of ≥ 2 cm of intrauterine fluid 24 h after AI, besides the fertility was determined by a sonographic pregnancy diagnosis 2 weeks after ovulation. RNA expressions were compared between susceptible non-pregnant (SNP) mares (n=9) and resistant pregnant (RP) mares (n=9) as well as between susceptible pregnant (SP) mares (n=9) and susceptible non-pregnant (SNP) mares. 66 differentially expressed genes (DEGs) were identified between SNP and RP mares and 60 DEGs between SP and SNP mares. In SNP compared to RP mares, transcript levels of genes regulating steroid hormone metabolism and neutrophil chemotaxis were lower, while higher for genes participating in uterine inflammation.Transcripts of genes related to extracellular matrix degradation, tissue adhesions, and fibrosis were lower in SP mares than in SNP mares, while higher for genes related to uterine cell proliferation, differentiation, and angiogenesis in SP mares than SNP mares. In conclusion, increased transcript levels of apolipoprotein E (APOE) and roundabout 2 (ROBO2), cluster domain 44 (CD44), integrin beta 3 (ITGB3), and epidermal growth factor (EGF) are possible biomarkers for susceptibility to PBIE. While higher expression of fibroblast growth factor 9 (FGF9), kinase domain receptor (KDR), and C-X-C motif chemokine ligand (CXCL) 16, collagen type V alpha 2 (COL5A2) and fibronectin (FN1) are suggested indicators of fertility in susceptible mares if they receive proper breeding management.

Modulation of E-Cadherin and N-Cadherin by ovarian steroids and embryonic stimuli

Endometrium is a dynamic tissue that undergoes extensive remodelling to attain a receptive state which is further modulated in presence of an embryo for successful initiation of pregnancy. Cadherins are the proteins of the junctional complex of which E-cadherin (E-Cad) is crucial for maintaining epithelial cell state and integrity of the epithelial barrier; gain of N-cadherin (N-Cad) in epithelial cells leads to epithelial to mesenchymal transition (EMT). In the present study, we investigated the expression of E-Cad and N-Cad in the mouse endometrial luminal epithelium and its modulation by estrogen, progesterone, and embryonic stimuli. We observed that E-Cad is diffusely expressed in the luminal epithelium of mouse endometrium during the estrus stage and upon estrogen treatment. It is apico-laterally and basolaterally sorted at the diestrus stage and in response to the combined treatment of estrogen and progesterone. In 3D spheroids of human endometrial epithelial cells, combined treatment with estrogen and progesterone led to lateral sorting of E-Cad without any effects on its mRNA levels. at the time of embryo implantation, there is loss of E-Cad along with the gain of N-Cad and SNAIL expression suggestive of EMT in the luminal epithelium. This EMT is possibly driven by embryonic stimuli as treatment with estrogen and progesterone did not lead to the gain of N-Cad expression in the mouse endometrium in vivo or in human endometrial epithelial cells in vitro. In conclusion, the present study demonstrates that steroid hormones directly affect E-Cad sorting in the endometrial epithelium which undergo EMT in response to embryonic stimuli.

Stationed or Relocating: The Seesawing EMT/MET Determinants from Embryonic Development to Cancer Metastasis

Epithelial and mesenchymal transition mechanisms continue to occur during the cell cycle and throughout human development from the embryo stage to death. In embryo development, epithelial-mesenchymal transition (EMT) can be divided into three essential steps. First, endoderm, mesoderm, and neural crest cells form, then the cells are subdivided, and finally, cardiac valve formation occurs. After the embryonic period, the human body will be subjected to ongoing mechanical stress or injury. The formation of a wound requires EMT to recruit fibroblasts to generate granulation tissues, repair the wound and re-create an intact skin barrier. However, once cells transform into a malignant tumor, the tumor cells acquire the characteristic of immortality. Local cell growth with no growth inhibition creates a solid tumor. If the tumor cannot obtain enough nutrition in situ, the tumor cells will undergo EMT and invade the basal membrane of nearby blood vessels. The tumor cells are transported through the bloodstream to secondary sites and then begin to form colonies and undergo reverse EMT, the so-called "mesenchymal-epithelial transition (MET)." This dynamic change involves cell morphology, environmental conditions, and external stimuli. Therefore, in this manuscript, the similarities and differences between EMT and MET will be dissected from embryonic development to the stage of cancer metastasis.

Nanomedicines for Endometriosis: Lessons Learned from Cancer Research

Endometriosis is an incurable gynecological disease characterized by the abnormal growth of endometrium-like tissue, characteristic of the uterine lining, outside of the uterine cavity. Millions of people with endometriosis suffer from pelvic pain and infertility. This review aims to discuss whether nanomedicines that are promising therapeutic approaches for various diseases have the potential to create a paradigm shift in endometriosis management. For the first time, the available reports and achievements in the field of endometriosis nanomedicine are critically evaluated, and a summary of how nanoparticle-based systems can improve endometriosis treatment and diagnosis is provided. Parallels between cancer and endometriosis are also drawn to understand whether some fundamental principles of the well-established cancer nanomedicine field can be adopted for the development of novel nanoparticle-based strategies for endometriosis. This review provides the state of the art of endometriosis nanomedicine and perspective for researchers aiming to realize and exploit the full potential of nanoparticles for treatment and imaging of the disorder.

Recepteur d'origine nantais contributes to the development of endometriosis via promoting epithelial-mesenchymal transition of a endometrial epithelial cells

Endometriosis is a benign, chronic inflammatory disease that commonly occurs in reproductive‐aged women. Epithelial‐mesenchymal transition (EMT) of endometrial epithelial cells plays an important role in the development of endometriosis. Recepteur d'origine nantais (RON), a receptor tyrosine kinase, has been reported to promote EMT and progression in tumours. However, whether and how RON mediates the EMT and endometriosis development is not known. Here, we found that RON activation could improve the migratory and invasive capabilities, change cellular morphologies, and decrease expression of E‐cadherin and increase expression of N‐cadherin in endometrial epithelial cells. Inhibition or knockdown of RON expression suppressed the migration and invasion of endometrial epithelial cells. Our studies also indicated that RON played its part in endometrial epithelial cells through protein kinase B (Akt) and mitogen‐activated protein kinase (MAPK) pathways. Treatment with a RON inhibitor could decrease the number of ectopic lesions in a mouse model of endometriosis and mediate expression of EMT markers in endometriotic lesions. These data suggest that RON contributed to endometriosis development by promoting EMT of endometrial epithelial cells. Therefore, RON may be a new therapeutic target for endometriosis.

Differential expression of Oct-4, CD44, and E-cadherin in eutopic and ectopic endometrium in ovarian endometriomas and their correlations with clinicopathological variables

BACKGROUND

Endometriosis is an estrogen-dependent inflammatory disease that often causes infertility and chronic pelvic pain. Although endometriosis is known as a benign disease, it has demonstrated characteristics of malignant neoplasms, including neoangiogenesis, tissue invasion, and cell implantation to distant organs. Octamer-binding protein 4 (Oct-4) is a molecular marker for stem cells that plays an essential role in maintaining pluripotency and self-renewal processes in various types of benign and malignant tissues. CD44 is a multifunctional cell surface adhesion molecule that acts as an integral cell membrane protein and plays a role in cell-cell and cell-matrix interactions. E-cadherin is an epithelial cell-cell adhesion molecule that plays important role in the modulation of cell polarization, cell migration, and cancer metastasis. The aim of this study was to investigate the expression patterns of Oct-4, CD44, and E-cadherin in eutopic and ectopic endometrial tissues from women with endometrioma compared to control endometrial tissues from women without endometrioma.

METHODS

In the present study, Oct-4, CD44, and E-cadherin expressions were evaluated in eutopic and ectopic endometrial tissue samples from women with endometrioma (n = 32) and compared with those of control endometrial tissue samples from women without endometrioma (n = 30).

RESULTS

Immunohistochemical expression of Oct-4 was significantly higher in the ectopic endometrial tissue samples of women with endometrioma than in the control endometrial tissue samples (p = 0.0002). Conversely, CD44 and E-cadherin expressions were significantly lower in the ectopic endometrial tissue samples of women with endometrioma than in the control endometrial tissue samples (p = 0.0137 and p = 0.0060, respectively). Correlation analysis demonstrated significant correlations between Oct-4 expression and endometrioma cyst diameter (p = 0.0162), rASRM stage (p = 0.0343), and total rASRM score (p = 0.0223). Moreover, CD44 expression was negatively correlated with the presence of peritoneal endometriotic lesions (p = 0.0304) while E-cadherin expression was negatively correlated with the presence of deep infiltrating endometriosis (p = 0.0445).

CONCLUSIONS

Increased expression of Oct-4 and decreased expression of adhesion molecules in endometriotic tissues may contribute to the development and progression of endometriosis.

Endometrial changes in estrogen and progesterone receptor expression during implantation in an oocyte donation program

Implantation is the final and most important stage of embryogenesis and is of paramount importance in achieving a successful pregnancy. Progesterone and estrogen are steroid hormones responsible for the regulation of the implantation window and the current study hypothesised that their receptors may be implicated in women undergoing oocyte donation. A total of 15 women aged 25-32 years old (mean ± SD, 28.9±2.89) undergoing oocyte donation were recruited into the present study. Participants underwent ovarian stimulation with gonadotrophin-releasing hormone antagonist and recombinant follicle-stimulating hormone. Endometrial aspiration biopsy was performed on the day of oocyte retrieval and after 5 days (on days 0 and 5, respectively). Endometrial histology and evaluation of estrogen receptor (ER)α and progesterone receptor (PR)-B were performed on days 0 and 5. The ER nodal staining percentage on day 0 was age-associated, with patients aged <30 years demonstrating 100% staining and those aged >30 years exhibiting 90% staining. Pathological staining revealed statistically significant differences between days 0 and 5 following all staining procedures. Wilcoxon signed-rank test resulted in the following P-values, for ER (nodes % and stromal %) day 0/5, P=0.0001; for PR (nodes % and stromal %) day 0/5, P=0.0001 and P=0.035, respectively; for ER (grade nodes and stromal %) day 0/5, P=0.0001; and PR (grade nodes and stromal %) day 0/5 P=0.0001 and P=0.016, respectively. Synchronization between blastocyst development and the acquisition of endometrial receptivity is a prerequisite for the success of in vitro fertilisation (IVF). Aside from the recent discovery of molecules that are considered crucial for successful embryo implantation, assessing the functional characteristics of the endometrium may offer unique insights into this process, thus improving IVF results.

Epidermal growth factor promotes stromal cells migration and invasion via up-regulation of hyaluronate synthase 2 and hyaluronan in endometriosis

OBJECTIVE

To investigate the role(s) of hyaluronan synthase 2 (HAS2) and hyaluronan in disease progression of endometriosis and epidermal growth factor (EGF)-induced motility changes of endometriotic cells.

DESIGN

A case-control experimental study and in vitro primary cell culture study.

SETTING

University hospital-affiliated research centers.

PATIENTS

A total of 21 women with stage I/II endometriosis, 33 women with stage III/IV endometriosis with endometrioma, and 32 women without endometriosis were included in our study.

INTERVENTIONS

Serum, eutopic endometrial tissues, and/or ectopic endometriotic tissues were collected. Primary eutopic endometrial stromal cells (EuESCs) and ectopic ovarian endometriotic stromal cells (OvESCs) were isolated and cultured from women with ovarian endometrioma, and then treated with or without EGF.

MAIN OUTCOME MEASURES

The concentrations of EGF and hyaluronan in serum were analyzed by enzyme-linked immunosorbent assay. The expressions and localizations of EGF receptor (EGFR), phosphorylated-(p)EGFR, HAS2, and hyaluronan receptor CD44 in tissues were examined by immunohistochemistry. The mRNA and protein levels of HAS2 in EuESCs and OvESCs were examined by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blot, respectively, and the concentrations of hyaluronan in conditioned medium were examined by enzyme-linked immunosorbent assay (ELISA). Cell motility was evaluated by transwell migration/invasion assays.

RESULTS

Serum EGF and hyaluronan concentrations were higher in women with stage III/IV endometriosis than in women with stage I/II or without endometriosis. EGFR, pEGFR, HAS2, and CD44 were immunolocalized in eutopic endometrium and ectopic endometriotic lesions, and the expressions of pEGFR and HAS2 were elevated in ectopic endometriotic lesions compared to eutopic endometrium. Treatment with EGF upregulated HAS2 and hyaluronan expression as well as cell migration and invasion in both EuESCs and OvESCs, and pharmaceutical blocking of EGFR abolished these effects. In addition, knockdown of HAS2 by small interfering RNA attenuated both basal and EGF-induced hyaluronan expression and cell motility changes. Notably, ERK1/2 and AKT signaling pathways were shown to be downstream of EGF in regulating HAS2 and hyaluronan expression as well as cell migration and invasion.

CONCLUSION

EGF increased the expression of endometriosis-associated hyaluronan and its synthase HAS2, both of which mediated EGF-induced stromal cell migration and invasion in women with endometriosis.

Characterization of the role for cadherin 6 in the regulation of human endometrial receptivity

BACKGROUND

The endometrial luminal epithelium is the first point of attachment of embryos during implantation. Failure of embryos to firmly adhere results in implantation failure and infertility. A receptive endometrial luminal epithelium is achieved through the expression of adhesion molecules in the mid-secretory phase and is a requirement for implantation. Cadherin 6 (CDH6) is an adhesion molecule localizing to the endometrial luminal epithelial cell surface in the mid-secretory/receptive phase and knockdown of CDH6 in the Ishikawa cells (receptive endometrial epithelial cell line) compromises cell integrity. However, there are no studies investigating the role of CDH6 on receptivity and infertility. This study aimed to investigate whether CDH6 is dysregulated in the endometrium of women with infertility during the receptive window and the effect of CDH6 on endometrial adhesion and receptivity.

METHODS

The expression and the localization of CDH6 in the human endometrium were determined by immunohistochemistry. Ishikawa cells were used to investigate the functional consequences of CDH6 knockdown on endometrial adhesive capacity to HTR8/SVneo (trophoblast cell line) spheroids in vitro. CDH6 knockdown was assessed by qPCR and immunoblotting. After CDH6 knockdown, the expression of type II cadherin family members and CDH6 functional partners were assessed by qPCR. Two-tailed unpaired student's t-test or one-way ANOVA as appropriate were used for statistical analysis with a significance threshold of P < 0.05.

RESULTS

A significant reduction of CDH6 immunolocalization was recorded in the luminal and glandular epithelium of endometrium from women with infertility (P < 0.05) compared to fertile group respective cellular compartments in the mid-secretory phase. Functional analysis using Ishikawa cells demonstrated that knockdown of CDH6 (treated with 50 nM CDH6 siRNA) significantly reduced epithelial adhesive capacity (P < 0.05) to HTR8/SVneo spheroids compared to control and other type II cadherin family members likely failed to compensate for the loss of CDH6. The expression levels of CDH6 functional partners, catenin family members were not changed after CDH6 knockdown in Ishikawa cells.

CONCLUSION

Together, our data revealed that CDH6 was dysregulated in the endometrium from women with infertility and altered Ishikawa cell adhesive capacity. Our study supports a role for CDH6 in regulating endometrial adhesion and implantation.

Epithelial-Mesenchymal Transition in Endometriosis-When Does It Happen?

Epithelial-mesenchymal transition (EMT) is an important process of cell remodeling characterized by the gradual loss of the epithelial phenotype and progressive gain of a mesenchymal phenotype. EMT is not an all-or-nothing process, but instead a transition of epithelial to mesenchymal cells with intermediate cell states. Recently, EMT was described in endometriosis, and many EMT-specific pathways like Twist, Snail, Slug, Zinc finger E-box-binding homeobox 1/2 (ZEB1/2), E/N-cadherin, keratins, and claudins are involved. However, as pointed out in this review, a comparison of the eutopic endometrium of women with and without endometriosis yielded only subtle changes of these EMT markers. Furthermore, only very few alterations in cell-cell contacts could be found but without changes in the epithelial phenotype. This suggests only a partial EMT which is not a prerequisite for the detachment of endometrial cells and, thus, not critical for the first step(s) in the pathogenesis of endometriosis. In contrast, the majority of changes in the EMT-related marker expression were found in the ectopic endometrium, especially in the three endometriotic entities, ovarian, peritoneal, and deep infiltrating endometriosis (DIE), compared with the eutopic endometrium. In this review, we examine the most important EMT pathways described in endometriosis and propose that partial EMT might result from the interaction of endometrial implants with their surrounding microenvironment.

Malignant Transformation and Associated Biomarkers of Ovarian Endometriosis: A Narrative Review

This review focuses on pathogenesis of endometriosis, its possible biomarkers and role in endometriosis-associated ovarian cancer. We analyzed various databases to obtain new insights, theories, and biomarkers associated with endometriosis. There are several theories of endometriosis development and biomarker changes including atypical forms. A number of studies have attempted to establish specific, reliable biomarkers to help diagnose endometriosis and endometriosis-associated diseases on the basis of different pathogenetic pathways. Nevertheless, despite intensive research extending even to the molecular level, the origin, natural history, malignant transformation, and laboratory management of endometriosis and related diseases are not yet clearly defined. Therefore, early laboratory diagnoses of endometriosis, its atypical form, and endometriosis-associated ovarian tumors are important problems that require further study in the context of advanced therapeutic strategies to provide maximal health benefits to patients.

Invasion of human deep nodular endometriotic lesions is associated with collective cell migration and nerve development

OBJECTIVE

To study the mechanisms of invasion and innervation of deep endometriosis in women.

DESIGN

Morphologic and immunohistochemical analysis of human endometriotic lesions.

SETTING

Academic research unit.

PATIENT(S)

Seventeen biopsy samples of deep endometriotic lesions were collected from patients undergoing surgery for deep endometriosis.

INTERVENTION(S)

The endometriotic samples were divided into two parts: the front (the most invasive area of lesions, approaching rectal infiltration) and center (the area close to the posterior part of the cervix).

MAIN OUTCOME(S)

To elucidate: gland morphology, proliferation, and expression of adhesion molecules (β-catenin, E-cadherin, and N-cadherin) to determine the possible role of collective cell migration (CCM) in the invasion process; and nerve growth factor (NGF) and nerve fiber density (NFD) values to shed further light on the mechanism of innervation.

RESULTS

Glands from the front showed significantly reduced thickness, but significantly higher proliferation. β-Catenin expression was similar between the lesion center and front. E-cadherin levels were significantly lower and N-cadherin levels significantly higher in glands located at the front of the lesions. Expression of matrix metalloproteinase-9 was significantly higher in glands and stromal cells located at the invasion front. NFD and NGF expression were also significantly higher at the lesion front.

CONCLUSION

Although some data in the literature point to features of epithelial to mesenchymal transition in human deep nodular endometriosis, our study suggests that gland invasion in these lesions is dominated by CCM. Innervation of deep nodular endometriotic lesions may be a consequence of nerve recruitment from surrounding organs.

Aberrant methylation of the IL-12B promotor region contributes to the risk of developing ovarian endometriosis

Studies have shown that aberrant expression of IL-12p40, which is encoded by the interleukin-12B (IL-12B) gene, may be involved in the development of endometriosis. In this study, we investigated the role of aberrant methylation of the IL-12B promoter region and its associated expression in the development of ovarian endometriosis. By using pyrosequencing, we analyzed the methylation level of the IL-12B promoter region in eutopic and ectopic endometrium of patients with ovarian endometriosis and normal endometrium of control women. The expression of IL-12B mRNA was detected by quantitative real-time PCR. The results showed that the methylation level of the IL-12B promoter region in ectopic and eutopic endometrium of patients with ovarian endometriosis was significantly lower than that in endometrium of women without endometriosis ( p < 0.001 and p = 0.041, respectively). In contrast, mRNA levels were significantly increased in ectopic and eutopic endometrium of patients with ovarian endometriosis compared to those in endometrium of women without endometriosis ( p < 0.001 and p = 0.042, respectively). Correlation analysis showed that the methylation level of the IL-12B promoter region was negatively correlated with mRNA levels of IL-12B ( p < 0.001). Our data suggested that aberrant methylation of the IL-12B promoter region may be responsible for aberrant IL-12B mRNA expression in endometrium tissue of women, which may be associated with the development of ovarian endometriosis in northern Chinese women.

Direct Cell⁻Cell Interactions in the Endometrium and in Endometrial Pathophysiology

Cell contacts exhibit a considerable influence on tissue physiology and homeostasis by controlling paracellular and intercellular transport processes, as well as by affecting signaling pathways. Since they maintain cell polarity, they play an important role in cell plasticity. The knowledge about the junctional protein families and their interactions has increased considerably during recent years. In contrast to most other tissues, the endometrium undergoes extensive physiological changes and reveals an extraordinary plasticity due to its crucial role in the establishment and maintenance of pregnancy. These complex changes are accompanied by changes in direct cell–cell contacts to meet the various requirements in the respective developmental stage. Impairment of this sophisticated differentiation process may lead to failure of implantation and embryo development and may be involved in the pathogenesis of endometrial diseases. In this article, we focus on the knowledge about the distribution and regulation of the different junctional proteins in the endometrium during cycling and pregnancy, as well as in pathologic conditions such as endometriosis and cancer. Decoding these sophisticated interactions should improve our understanding of endometrial physiology as well as of the mechanisms involved in pathological conditions.

Expression and shedding of CD44 in the endometrium of women with endometriosis and modulating effects of vitamin D: A randomized exploratory trial

Endometriosis is an estrogen-dependent disease. The impaired estrogen and progesterone signaling over-activates the Wnt/β-catenin pathway in endometriosis patients, which can explain the increased invasion potency of endometrial cells derived from the endometrium of women with endometriosis. The regulatory effects of vitamin D on Wnt/β-catenin pathway were demonstrated by previous studies. According to gene prioritization method, among Wnt target genes, CD44 was in high ranking in relation to endometriosis. The aim of this study is to investigate the expression of CD44 in the endometrium of women with endometriosis and to study the effects of vitamin D on its expression. This prospective study was performed, during a 12 months period from December 2015 to November 2016, on healthy women as the control group (n = 14) and endometriosis patients (n = 34). The endometriosis patients randomly divided into two groups: One group treated according to the routine protocol and the other group, alongside the routine protocol, took 50,000 IU vitamin D weekly for 12-14 weeks. Blood, endometrial fluid, and endometrial tissue samples were obtained from the control group and endometriosis groups before and after the intervention. We used in silico gene prioritization to study the relevance of CD44. The expression of CD44 was evaluated using the techniques of Western blot, real-time polymerase chain reaction, and ELISA. The eutopic endometrium of women with endometriosis in mid-secretory phase expressed significantly higher levels of CD44s, CD44V, and CD44v6. The concentration of soluble CD44 in the serum and endometrial fluid of endometriosis patients was higher than of healthy women. The expression level of CD44s, CD44V, and CD44v6 in the eutopic endometrium as well as the concentration of soluble CD44 in the endometrial fluid was decreased after modification of the circulating levels of 25(OH)D. It seems that the increased expression and extensive shedding of CD44 in eutopic endometrium play a role in the pathogenesis of endometriosis. Vitamin D can control and modify this process at least in part. We suggest more in vivo investigations on the therapeutic potency of vitamin D in endometriosis.

Differentially expressed genes: OCT-4, SOX2, STAT3, CDH1 and CDH2, in cultured mesenchymal stem cells challenged with serum of women with endometriosis

Endometriosis is a common chronic gynecological disorder defined as the presence of ectopic functional endometrial tissues, outside uterine cavity, primarily on the pelvic peritoneum and the ovaries. Several studies revealed a correlation between aberrant stem-cell activity in the endometrium and endometriosis. Yet the molecular and cellular behaviors of mesnchymal stem cells in development of endometriosis are hampered by lack of invitro experiments. Our aim was to explore morphological and molecular changes associated with mesenchymal stem cells (MSCs) exposition to serum derived from women with severe endometriosis. Two cell cultures of MSCs isolated from endometrial tissues of two endometriosis-free women. Each cell culture was treated individually with the serum of women with endometriosis (experimental group/n = 7), and serum of women without endometriosis (control group/ n = 4) for 14 days. Quantitative Real-Time PCR was performed later to reveal expression of OCT-4, CDH1 and CDH2, STAT3 and SOX2 genes. Morphologically, cells showed no significant changes. However from molecular point of view, we found increased expression in OCT-4, CDH1 and CDH2. For STAT3 and SOX2 we did not find a significant difference. This study shows that endometriosis serum induced molecular changes in human endometrial MSCs (EnMSCs) that might be related to altered cell behavior which may be a step in differentiation that may be completed invivo by other factors to complete the process of transition. Further researches are needed for optimization to reach differentiation.

Knockdown of E-cadherin expression of endometrial epithelial cells may activate Wnt/β-catenin pathway in vitro

PURPOSE

E-cadherin, a transmembrane glycoprotein mediating Ca²⁺-independent homotypic cell-cell adhesion in epithelial cell, plays an essential role in metastasis. It has been postulated that E-cadherin downregulation is a crucial mechanism in the pathogenesis of endometriosis. To evaluate the effect on the cell behavior after knockdown of E-cadherin gene (CDH1) in cultured human endometrial epithelial cells (EECs) isolated from normal endometrium.

METHODS

EECs were isolated from the endometrial tissues of fertile woman who underwent total hysterectomy due to cervical intraepithelial neoplasia III. CDH1 expression was knocked down by small hairpin RNA. The EECs transfected with empty vector served as control. Transwell assay was used to test EECs migration or invasion. qRT-PCR and western blot were used to detect mRNA and protein levels.

RESULTS

The results showed that knockdown of E-cadherin expression can increase cell migration and invasion, and up-regulate mRNA and protein levels of β-catenin, cyclinD1, and c-myc.

CONCLUSIONS

Down-regulation of E-cadherin expression may activate the Wnt/β-catenin pathway in endometrial cells, which may together participate in the occurrence of endometriosis.

ZEB1 expression is a potential indicator of invasive endometriosis

INTRODUCTION

Although endometriosis is a benign disease, it shares some features with cancers, such as invasiveness and the potential to metastasize. This study sought to investigate the epithelial-mesenchymal transition status in human endometriotic lesions.

MATERIAL AND METHODS

Thirteen endometriosis patients and 10 control women without endometriosis undergoing surgery for benign indications were recruited. We examined the expression of E-cadherin, vimentin, and epithelial-mesenchymal transition-induced transcriptional factors, such as Snail and ZEB1, by immunohistochemistry. We evaluated the expression of each marker in epithelial cells of both endometriotic lesions (ovarian endometrioma, deep infiltrating endometriosis, adenomyosis) and normal endometria. The correlation between ZEB1 expression and serum level of CA125 was also investigated.

RESULTS

Immunohistochemical analysis revealed that although E-cadherin, vimentin, and Snail were expressed in epithelia of normal endometria and endometriotic lesions, ZEB1 expression was only expressed in epithelia of endometriotic lesions. Additionally, ZEB1 was most frequently observed in epithelial cells of invasive endometriosis. The endometriosis patients with high serum CA125 level were more likely to have ZEB1-positive lesions.

CONCLUSIONS

This is the first observation of ZEB1 expression in epithelial cells of benign disease. The preferential expression of ZEB1 in epithelial cells of endometriotic lesions suggests that these cells may have, at least in part, a higher level of mesenchymal features possibly via ZEB1-driven epithelial-mesenchymal transition than normal endometria and that ZEB1 can be a potential indicator of invasiveness or severity of endometriosis.

High Molecular Weight Hyaluronic Acid Inhibits Fibrosis of Endometrium

Background

Elevated fibrosis has been found in patients with intrauterine adhesion, which indicates that fibrotic factors may play a critical role in formation of intrauterine adhesion. The aim of this study was to identify the effect of hyaluronic acid (HA) at high and low molecular weight on fibrosis of the endometrium in a mouse model of Asherman’s syndrome.

Material/Methods

Endometrial fibrosis in a mouse model of Asherman’s syndrome was confirmed. Then HA at high and low molecular weight was injected into the uterine cavity. Endometrial fibrosis was compared among the control group, LMW-HA, and HMW-HA group. The extent of endometrial fibrosis was calculated using Masson stain. The fibrosis markers (TGFβ1, CTGF, collagen I, and collagen III) in endometrial tissue were detected using immunohistochemistry and Western blotting.

Results

The ratio of the area with endometrial fibrosis to total endometrial area in the HMW-HA group was significantly decreased compared to the control group (P<0.05). The expression of fibrosis markers (TGFβ1, CTGF, collagen I, and collagen III) in the endometrium was attenuated in the HMW-HA group compared to the control group, but the LMW-HA group had no similar effect.

Conclusions

Hyaluronic acid at high molecular weight may attenuate the degree of endometrial fibrosis after endometrial damage, which may contribute to preventing formation of intrauterine adhesions.

Paeonia lactiflora Enhances the Adhesion of Trophoblast to the Endometrium via Induction of Leukemia Inhibitory Factor Expression

In the present study, we investigated the role of Paeonia lactiflora Pall. extract on embryo implantation in vitro and in vivo. A polysaccharides depleted-water extract of P. lactiflora (PL-PP) increased LIF expression in human endometrial Ishikawa cells at non-cytotoxic doses. PL-PP significantly increased the adhesion of the human trophectoderm-derived JAr spheroids to endometrial Ishikawa cells. PL-PP-induced LIF expression was decreased in the presence of a p38 kinase inhibitor SB203580 and an MEK/ERK inhibitor U0126. Furthermore, endometrial LIF knockdown by shRNA reduced the expression of integrins β3 and β5 and adhesion of JAr spheroids to Ishikawa cells. In vivo administration of PL-PP restored the implantation of mouse blastocysts in a mifepristone-induced implantation failure mice model. Our results demonstrate that PL-PP increases LIF expression via the p38 and MEK/ERK pathways and favors trophoblast adhesion to endometrial cells.

Enhanced epithelial to mesenchymal transition (EMT) and upregulated MYC in ectopic lesions contribute independently to endometriosis

BACKGROUND

Epithelial to mesenchymal transition (EMT) is a process in which epithelial cells lose polarity and cell-to-cell contacts and acquire the migratory and invasive abilities of mesenchymal cells. These abilities are thought to be prerequisites for the establishment of endometriotic lesions. A hallmark of EMT is the functional loss of E-cadherin (CDH1) expression in epithelial cells. TWIST1, a transcription factor that represses E-cadherin transcription, is among the EMT inducers. SNAIL, a zinc-finger transcription factor, and its close relative SLUG have similar properties to TWIST1 and are thus also EMT inducers. MYC, which is upregulated by estrogens in the uterus by an estrogen response cis-acting element (ERE) in its promoter, is associated with proliferation in endometriosis. The role of EMT and proliferation in the pathogenesis of endometriosis was evaluated by analyzing TWIST1, CDH1 and MYC expression.

METHODS

CDH1, TWIST1, SNAIL and SLUG mRNA expression was analyzed by qRT-PCR from 47 controls and 74 patients with endometriosis. Approximately 42 ectopic and 62 eutopic endometrial tissues, of which 30 were matched samples, were collected during the same surgical procedure. We evaluated TWIST1 and MYC protein expression by immunohistochemistry (IHC) in the epithelial and stromal tissue of 69 eutopic and 90 ectopic endometrium samples, of which 49 matched samples were analyzed from the same patient. Concordant expression of TWIST1/SNAIL/SLUG and CDH1 but also of TWIST1 and MYC was analyzed.

RESULTS

We found that TWIST1, SNAIL and SLUG are overexpressed (p < 0.001, p = 0.016 and p < 0.001) in endometriosis, while CDH1 expression was concordantly reduced in these samples (p < 0.001). Similar to TWIST1, the epithelial expression of MYC was also significantly enhanced in ectopic endometrium compared to eutopic tissues (p = 0.008). We found exclusive expression of either TWIST1 or MYC in the same samples (p = 0.003).

CONCLUSIONS

Epithelial TWIST1 is overexpressed in endometriosis and may contribute to the formation of endometriotic lesions by inducing epithelial to mesenchymal transition, as CDH1 was reduced in ectopic lesions. We found exclusive expression of either TWIST1 or MYC in the same samples, indicating that EMT and proliferation contribute independently of each other to the formation of endometriotic lesions.

Soluble CD44 concentration in the serum and peritoneal fluid samples of patients with different stages of endometriosis

PURPOSE

Endometriosis is a gynecological disease defined by the histological presence of endometrial glands and stroma outside the uterine cavity, most commonly implanted over visceral and peritoneal surface within the female pelvis. CD44 is a membrane protein expressed by human endometrial cells, and it has been shown to promote the adhesion of endometrial cells. The aim of this study was to determine the levels of soluble CD44 (sCD44) in the serum and peritoneal fluid (PF) samples of patients with different stages of endometriosis.

METHODS

39 PF and serum samples from normal healthy and 130 samples from different stages of patients with endometriosis (33 cases of stage I, 38 stage II, 30 stage III and 29 stage IV) were included in this study. Total protein concentration (TPC) and the level of s-cMet in the serum were determined by Bio-Rad protein assay based on the Bradford dye procedure and enzyme-linked immunosorbent assay, respectively.

RESULTS

No significant change in the TPC was seen in the serum of patients with endometriosis when compared to normal controls. Results obtained demonstrated that all serum and peritoneal fluid samples, presented sCD44 expression, whereas, starting from stages I to IV endometriosis, a significant increase of sCD44 expression was observed as compared to control group.

CONCLUSIONS

The results of this study show that a high expression of sCD44 is correlated with advanced stages of endometriosis. It is also concluded that the detection of serum and/or peritoneal fluid sCD44 may be useful in classifying endometriosis.

Genetic variation of the E-cadherin gene is associated with primary infertility in patients with ovarian endometriosis

OBJECTIVE

To explore the association between the genetic variant of E-cadherin gene and endometriosis-related infertility.

DESIGN

Case-control study.

SETTING

University hospital.

PATIENT(S)

Five hundred eighty-nine women with ovarian endometriosis including 127 patients with primary infertility and 589 female controls in northern China.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Single nucleotide polymorphisms (SNPs) in the promoter region, exons, and the 3' untranslated region of the E-cadherin gene were identified by direct sequencing in patients with ovarian endometriosis and with polymerase chain reaction (PCR). Six candidate SNPs (rs16260, rs28372783, rs1801552, rs1801026, rs8049282, and rs13689) were genotyped by PCR and ligase detection reaction.

RESULT(S)

The results revealed a significant association of rs8049282 SNP on E-cadherin gene with endometriosis-related infertility. When compared with control women or endometriosis patients who had a history of successful fertility, the CC genotype of rs8049282 may significantly increase the risk of primary infertility in patients with ovarian endometriosis (adjusted odds ratio [OR] = 2.70, 95% confidence interval [CI] 1.45-5.00; OR = 2.54, 95% CI 1.45-4.44, respectively).

CONCLUSION(S)

Our results suggested that genetic variants on the E-cadherin gene may be involved in endometriosis-related infertility. The rs8049282 SNP of the E-cadherin gene may be a potential molecular marker for the development of primary infertility in northern Chinese women with ovarian endometriosis.

CD44 expression in curettage and postoperative specimens of endometrial cancer

BACKGROUND

Adhesive molecules like CD44 are well defined key players in the metastatic cascade in many cancers, including endometrial cancer. They could play a role of markers of invasion, metastasis and prognostic factors.

AIM OF THE STUDY

The aim of the study is to assess a possible role of the CD44 as a marker of invasion in endometrial cancer, both at the moment of preoperative workup and final staging.

MATERIALS AND METHODS

Available for analysis were archival specimens of 51 patients who had underwent curettage and surgery between 2002 and 2007. An immunohistochemical study for CD44 expression was performed in curettage and postoperative specimens. Normal endometrium of 20 randomly chosen patients was used as a control group.

RESULTS

In endometrial cancer the expression of CD44 was significantly more intensive than in normal endometrium. In postoperative specimens, the CD44 expression was weaker in serous than in endometrioid cancer. There was no significant correlation between the adhesion molecule expression and clinicopathological features: grade,depth of invasion, cervical involvement, serosal and adnexal involvement, lymph-vascular space involvement, lymph node and distant metastases nor FIGO stage.

CONCLUSIONS

An increased expression of CD44 in endometrial cancer suggests its possible role in pathogenesis of this disease, however, it doesn't seem to be crucial. Different expression of the CD44 in endometrioid and papillary-serous type may reflect different pathogenesis of these types of cancer. No statistically proved relation between the investigated molecule expression and clinicopathological parameters suggests scepticism about its use in diagnostic process of endometrial cancer.

Molecular aspects of development and regulation of endometriosis

Endometriosis is a common and painful condition affecting women of reproductive age. While the underlying pathophysiology is still largely unknown, much advancement has been made in understanding the progression of the disease. In recent years, a great deal of research has focused on non-invasive diagnostic tools, such as biomarkers, as well as identification of potential therapeutic targets. In this article, we will review the etiology and cellular mechanisms associated with endometriosis as well as the current diagnostic tools and therapies. We will then discuss the more recent genomic and proteomic studies and how these data may guide development of novel diagnostics and therapeutics. The current diagnostic tools are invasive and current therapies primarily treat the symptoms of endometriosis. Optimally, the advancement of "-omic" data will facilitate the development of non-invasive diagnostic biomarkers as well as therapeutics that target the pathophysiology of the disease and halt, or even reverse, progression. However, the amount of data generated by these types of studies is vast and bioinformatics analysis, such as we present here, will be critical to identification of appropriate targets for further study.

Epithelial to mesenchymal transition (EMT) seems to be regulated differently in endometriosis and the endometrium

PURPOSE

Epithelial-mesenchymal transition (EMT) endows cells with migratory and invasive properties, a prerequisite for the establishment of endometriotic lesions. However, the role EMT might play in the pathophysiology of endometriosis is still unknown. Therefore, we examined five recognized markers for EMT in endometrium and endometriosis: E-cadherin, N-cadherin, Twist, Snail and Slug.

METHODS

Immunohistochemistry was used for peritoneal, ovarian and rectovaginal endometriotic lesions (n = 27) and endometrium (n = 13). Reverse transcription polymerase chain reaction was applied to tissue samples and primary cell cultures of endometriotic lesions (n = 9) and endometrium (n = 8).

RESULTS

In endometriosis and endometrium E-cadherin, N-cadherin, Twist, Snail and Slug were expressed on protein and mRNA level. E-cadherin expression was strong in epithelial cells, but single E-cadherin-negative cells were frequently present in endometriosis. In endometriosis N-cadherin, Twist and Snail expression were upregulated in comparison with endometrium. The expression of E- and N-cadherin was inversely correlated, while that of N-cadherin and Twist was positively correlated.

CONCLUSION

This study strongly suggests that EMT may be regulated differently in endometriosis and the endometrium. Future research should further elucidate the regulation of EMT in the endometrium and endometriosis.

Possible involvement of CD10 in the development of endometriosis due to its inhibitory effects on CD44-dependent cell adhesion

A reduced response to progesterone in the eutopic endometrium with endometriosis and in endometriotic tissues is considered to be the underlying factor for endometriosis. CD10 is known to be expressed by endometrial and endometriotic stromal cells and may be induced by progestins, although the function of CD10 is not fully revealed in endometrial or endometriotic tissues. In the current study, the expression of CD10 was significantly increased by treatment of the cells with progesterone, 17β-estradiol, and dibutyryl cyclic adenosine monophosphate (cAMP) in the endometrial stromal cells. On the other hand, the expression of CD10 following treatment with progesterone, 17β-estradiol, and dibutyryl cAMP was not significantly increased in endometriotic stromal cells. The adhesion assay for endometrial and endometriotic stromal cells to hyaluronan using 5- or 6-(N-succinimidyloxycarbonyl)-fluorescein 3', 6'-diacetate-labeled cells demonstrated that the CD44-dependent adhesion of stromal cells was inhibited by CD10. As far as the induction of CD10 is concerned, the effect of progesterone was different between endometrial stromal cells and endometriotic stromal cells. CD10 might be involved in the development of endometriosis due to its influence on CD44-dependent cell adhesion.

Estrogen and progesterone together expand murine endometrial epithelial progenitor cells

Synchronous with massive shifts in reproductive hormones, the uterus and its lining the endometrium expand to accommodate a growing fetus during pregnancy. In the absence of an embryo the endometrium, composed of epithelium and stroma, undergoes numerous hormonally regulated cycles of breakdown and regeneration. The hormonally mediated regenerative capacity of the endometrium suggests that signals that govern the growth of endometrial progenitors must be regulated by estrogen and progesterone. Here, we report an antigenic profile for isolation of mouse endometrial epithelial progenitors. These cells are EpCAM(+) CD44(+) ITGA6(hi) Thy1(-) PECAM1(-) PTPRC(-) Ter119(-), comprise a minor subpopulation of total endometrial epithelia and possess a gene expression profile that is unique and different from other cells of the endometrium. The epithelial progenitors of the endometrium could regenerate in vivo, undergo multilineage differentiation and proliferate. We show that the number of endometrial epithelial progenitors is regulated by reproductive hormones. Coadministration of estrogen and progesterone dramatically expanded the endometrial epithelial progenitor cell pool. This effect was not observed when estrogen or progesterone was administered alone. Despite the remarkable sensitivity to hormonal signals, endometrial epithelial progenitors do not express estrogen or progesterone receptors. Therefore, their hormonal regulation must be mediated through paracrine signals resulting from binding of steroid hormones to the progenitor cell niche. Discovery of signaling defects in endometrial epithelial progenitors or their niche can lead to development of better therapies in diseases of the endometrium.

Sex steroids regulate epithelial-stromal cell cross talk and trophoblast attachment invasion in a three-dimensional human endometrial culture system

Human embryo implantation involves a complex network of molecular signaling that is modulated by endocrine and paracrine pathways. Here, we performed studies using a unique and recently developed three-dimensional (3D) implantation model, characterized by an endometrium-like 3D culture system and Jar cell-derived spheroids mimicking the embryo/trophoblast. The aims were to investigate the effects of 17β estradiol (E2) and medroxyprogesterone acetate (MPA) on (1) the interaction between epithelial and stromal cells, and (2) the attachment and invasion of trophoblast cells. We observed that epithelial and stromal cells in the 3D culture were ERα⁺, ERβ⁺, and PR⁺. Decidualization was confirmed by enhanced prolactin gene expression on day 7 of E2 plus MPA treatment. An effect of epithelial cells on the decidualization of stromal cells was indicated by significantly higher levels of prolactin mRNA expression in the 3D culture compared to stromal cells grown within the fibrin-agarose gel matrix. On the other hand, the relative gene expressions of E-cadherin and IL-1β in epithelial cells of the 3D culture under decidualization conditions significantly differed from those in epithelial cells grown over the fibrin-agarose gel matrix without stromal cells, pointing to regulation of epithelial cells by the stroma. The attachment rate of Jar spheroids to the 3D was significantly increased by E2 plus MPA treatment. Analyses of Z-stack confocal and stained optic microscopic images demonstrated that Jar spheroids breached the epithelial cell monolayer, invaded, and were embedded into the 3D matrix in response to decidualization signals. In summary, the newly bioengineered system provides a unique model for studying interactions between the different endometrial cell compartments, via soluble-paracrine signals as well as cell-to-cell interactions, and is a useful tool to study early embryonic implantation events.

Endometrium in women with polycystic ovary syndrome during the window of implantation

The human endometrium undergoes to a complex series of proliferative and secretory changes in each menstrual cycle and displays only a short period of receptivity, known as the "window of implantation", necessary for the implantation of the blastocyst in the uterus. The implantation process occurs in a sequential manner, leading to the establishment of pregnancy. Morphofunctional changes during this period may prevent or hinder the implantation. For this reason, the study of the endometrium at this stage is important for the improvement of therapies that may interfere with the mechanisms involved in maternal-embryonic interaction. Several gynecological disorders, including polycystic ovary syndrome (PCOS), are associated with decreased fertility and uterine receptivity. In spite of recent advances in assisted reproduction techniques, allowing the selection of high quality embryos, the implantation rate remains low and has not increased enough in recent decades. This article aims at reviewing the endometrial aspects of the "window of implantation" in women with polycystic ovary syndrome, focusing mainly on adhesion molecules. For that purpose, we analyzed 105 articles published in journals indexed in PubMed in the last 50 years (up to May 2011). In conclusion, the endometrial receptivity seems to be the major limiting factor for the establishment of pregnancy in a large number of gynecological diseases, including PCOS, and treatment to improve implantation rates is likely to be taken towards this direction.

Association of E-cadherin single nucleotide polymorphisms with the increased risk of endometriosis in Indian women

The objective of the present study was to investigate the association between gene E-cadherin single nucleotide polymorphisms (SNPs) and risk of developing endometriosis in Indian women and to evaluate the role of E-cadherin expression in the pathophysiology of endometriosis. A genetic association study was conducted in 715 endometriosis cases and 500 controls of Indian origin. We genotyped -160 C/A, +54 C/T and -347 G/GA SNPs of gene E-cadherin by PCR-sequencing and PCR-restriction fragment length polymorphism techniques. Haplotype frequencies for multiple loci and the standardized disequilibrium coefficient (D') for pair-wise linkage disequilibrium (LD) were assessed by Haploview Software. In addition, to better understand genetic contributions to the pathophysiology of endometriosis, the expression pattern of E-cadherin in the endometrium of women with and without endometriosis was analyzed by western blot and immunohistochemical analysis. The frequencies of -347GA/GA (P = 0.026) and -160A/A (P = 0.0019) genotypes and -347G/-160A/+54C (P = 0.007) and -347GA/-160A/+54C (P < 0.0001) haplotypes were significantly different between patients and controls. Strong LD was observed between -347G/GA and -160C/A loci (D' = 0.64) when compared with -347G/GA and +54C/T (D' = 0.585) or -160C/A and +54C/T (D' = 0.05) loci in cases. Furthermore, increased membranous E-cadherin expression was observed in cases than in controls. The expression seems to be genotype dependent. In conclusion, the E-cadherin -347GA/GA and -160A/A genotypes and -347GA/-160A/+54C and -347G/-160A/+54C haplotypes may jointly modify the risk of endometriosis in Indian women. In addition, the differential expression of E-cadherin may play an important role in pathogenesis of endometriosis.

MicroRNAs are associated with human embryo implantation defects

BACKGROUND

Repeated implantation failure (RIF) is a major problem encountered in IVF. We have previously reported that RIF-IVF patients have a different endometrial gene expression profile during the window of implantation. Considering microRNA (miRNA) function in post-transcriptional regulation of gene expression, the aim of the study was to evaluate the involvement of miRNA in defects of endometrial receptivity.

METHODS

We used TaqMan miRNA array cards to identify the miRNAs differentially expressed in the secretory endometrium of RIF-IVF patients when compared with fertile women, and bioinformatics tools to identify their predicted targets and the molecular networks they may affect.

RESULTS

Comparing miRNA expression profiles, we identified 13 miRNAs, differentially expressed in RIF endometrial samples, that putatively regulate the expression of 3800 genes. We found that 10 miRNAs were overexpressed (including miR 145, 23b and 99a) and 3 were underexpressed. Using our previous gene expression analysis, we paralleled miRNA-mRNA expression profiling. By this means, we identified novel and previously characterized miRNA-regulated molecular pathways such as adherens junctions, cell adhesion molecules, Wnt-signaling, p53 signaling and cell cycle pathways. Consistent with the miRNA-predicted targets, mRNA levels of N-cadherin, H2AFX, netrin-4 and secreted frizzled-related protein-4, belonging to the cell adhesion molecules, Wnt signaling and cell cycle pathways were lower in RIF-IVF patients.

CONCLUSIONS

To our knowledge, this is the first study to evaluate the differential expression of miRNAs in the secretory endometrium of RIF-IVF patients. We suggest that the RIF-associated miRNAs could be exploited as new candidates for diagnosis and treatment of embryo implantation failures.

Attachment to extracellular matrices is enhanced in human endometriotic stromal cells: a possible mechanism underlying the pathogenesis of endometriosis

OBJECTIVE

Endometriosis is characterized by the ectopic growth of endometrial tissue. One of the first steps to the spread of endometriosis in the peritoneal cavity is the attachment of endometriotic cells to peritoneal surfaces after they have been released into the peritoneal fluid from pre-existing endometriotic lesions. The increased adhesive and proliferative potential of endometriotic cells in response to specific extracellular matrix (ECM) components has been suggested to contribute to the pathogenesis of endometriosis.

STUDY DESIGN

Adhesive properties of endometriotic stromal cells (ECSC) and normal eutopic endometrial cells (NESC) to various extracellular matrix proteins were investigated by in vitro cell adhesion assays. The expression levels of integrins in these cells were also examined by Western blot analysis.

RESULTS

Both ECSC and NESC significantly adhered to collagen type I and collagen type IV. ECSC revealed higher adhesive properties to these ECM proteins than NESC did. ECSC, but not NESC, adhered to fibronectin and laminin. Higher levels integrin of α1, α2, αv, β1, and β3 protein expression were observed in ECSC than in NESC. On the other hand, the levels of integrin α3 and αL proteins were lower in ECSC than in NESC.

CONCLUSIONS

The results suggest that endometriotic cells possess stronger adhesion to ECM proteins, and that increase may be mediated, in part, through integrins. These findings may elucidate one of the mechanisms underlying the formation of peritoneal endometriotic lesions.