Cadherin expression in gastrointestinal tract endometriosis: possible role in deep tissue invasion and development of malignancy

Digestive system deep infiltrating endometriosis: What do we know

Digestive system infiltrating endometriosis (DSIE) is an uncommon form of endometriosis in the digestive system. DSIE often occurs in the intestines (especially the sigmoid rectum), liver, gallbladder and pancreas. Clinically, DSIE presents with the same symptoms as endometriosis, including cyclic pain, bleeding and infertility, in addition to specific biliary/intestinal obstruction and gastrointestinal bleeding. Compared to general endometriosis, DSIE has unique biological behaviour and pathophysiological mechanisms. Most DSIEs are deep invasive endometrioses, characterized by metastasis to the lymph nodes and lymphatic vessels, angiogenesis, peripheral nerve recruitment, fibrosis and invasion of surrounding tissues. DSIE-related peripheral angiogenesis is divided into three patterns: angiogenesis, vasculogenesis and inosculation. These patterns are regulated by interactions between multiple hypoxia-hormone cytokines. The nerve growth factors regulate the extensive neurofibril recruitment in DSIE lesions, which accounts for severe symptoms of deep pain. They are also associated with fibrosis and the aggressiveness of DSIE. Cyclic changes in DSIE lesions, recurrent inflammation and oxidative stress promote repeated tissue injury and repair (ReTIAR) mechanisms in the lesions, accelerating fibril formation and cancer-related mutations. Similar to malignant tumours, DSIE can also exhibit aggressiveness derived from collective cell migration mediated by E-cadherin and N-cadherin. This often makes DSIE misdiagnosed as a malignant tumour of the digestive system in clinical practice. In addition to surgery, novel treatments are urgently required to effectively eradicate this lesion.

Adherens junction proteins on the move—From the membrane to the nucleus in intestinal diseases

The function and structure of the mammalian epithelial cell layer is maintained by distinct intercellular adhesion complexes including adherens junctions (AJs), tight junctions, and desmosomes. The AJ is most integral for stabilizing cell-cell adhesion and conserving the structural integrity of epithelial tissues. AJs are comprised of the transmembrane protein E-cadherin and cytoplasmic catenin cofactors (α, β, γ, and p120-catenin). One organ where malfunction of AJ is a major contributor to disease states is the mammalian intestine. In the intestine, cell-cell adhesion complexes work synergistically to maintain structural integrity and homeostasis of the epithelium and prevent its malfunction. Consequently, when AJ integrity is compromised in the intestinal epithelium, the ensuing homeostatic disruption leads to diseases such as inflammatory bowel disease and colorectal carcinoma. In addition to their function at the plasma membrane, protein components of AJs also have nuclear functions and are thus implicated in regulating gene expression and intracellular signaling. Within the nucleus, AJ proteins have been shown to interact with transcription factors such as TCF/LEF and Kaiso (ZBTB33), which converge on the canonical Wnt signaling pathway. The multifaceted nature of AJ proteins highlights their complexity in modulating homeostasis and emphasizes the importance of their subcellular localization and expression in the mammalian intestine. In this review, we summarize the nuclear roles of AJ proteins in intestinal tissues; their interactions with transcription factors and how this leads to crosstalk with canonical Wnt signaling; and how nuclear AJ proteins are implicated in intestinal homeostasis and disease.

Endometrial Stem/Progenitor Cells–Their Role in Endometrial Repair and Regeneration

The human endometrium is a remarkable tissue, undergoing ~450 cycles of proliferation, differentiation, shedding (menstruation), repair, and regeneration over a woman's reproductive lifespan. Post-menstrual repair is an extremely rapid and scar-free process, with re-epithelialization of the luminal epithelium completed within 48 h of initiation of shedding. Following menstruation, the functionalis grows from the residual basalis layer during the proliferative phase under the influence of rising circulating estrogen levels. The regenerative capacity of the endometrium is attributed to stem/progenitor cells which reside in both the epithelial and stromal cell compartments of the basalis layer. Finding a definitive marker for endometrial epithelial progenitors (eEPCs) has proven difficult. A number of different markers have been suggested as putative progenitor markers including, N-cadherin, SSEA-1, AXIN2, SOX-9 and ALDH1A1, some of which show functional stem cell activity in in vitro assays. Each marker has a unique location(s) in the glandular epithelium, which has led to the suggestion that a differentiation hierarchy exists, from the base of epithelial glands in the basalis to the luminal epithelium lining the functionalis, where epithelial cells express different combinations of markers as they differentiate and move up the gland into the functionalis away from the basalis niche. Perivascular endometrial mesenchymal stem cells (eMSCs) can be identified by co-expression of PDGFRβ and CD146 or by a single marker, SUSD2. This review will detail the known endometrial stem/progenitor markers; their identity, location and known interactions and hierarchy across the menstrual cycle, in particular post-menstrual repair and estrogen-driven regeneration, as well as their possible contributions to menstruation-related disorders such as endometriosis and regeneration-related disorder Asherman's syndrome. We will also highlight new techniques that allow for a greater understanding of stem/progenitor cells' role in repair and regeneration, including 3D organoids, 3D slice cultures and gene sequencing at the single cell level. Since mouse models are commonly used to study menstruation, repair and regeneration we will also detail the mouse stem/progenitor markers that have been investigated in vivo.

LINC01133 Inhibits Invasion and Promotes Proliferation in an Endometriosis Epithelial Cell Line

Endometriosis is a common gynecological disorder characterized by ectopic growth of endometrium outside the uterus and is associated with chronic pain and infertility. We investigated the role of the long intergenic noncoding RNA 01133 (LINC01133) in endometriosis, an lncRNA that has been implicated in several types of cancer. We found that LINC01133 is upregulated in ectopic endometriotic lesions. As expression appeared higher in the epithelial endometrial layer, we performed a siRNA knockdown of LINC01133 in an endometriosis epithelial cell line. Phenotypic assays indicated that LINC01133 may promote proliferation and suppress cellular migration, and affect the cytoskeleton and morphology of the cells. Gene ontology analysis of differentially expressed genes indicated that cell proliferation and migration pathways were affected in line with the observed phenotype. We validated upregulation of p21 and downregulation of Cyclin A at the protein level, which together with the quantification of the DNA content using fluorescence-activated cell sorting (FACS) analysis indicated that the observed effects on cellular proliferation may be due to changes in cell cycle. Further, we found testis-specific protein kinase 1 (TESK1) kinase upregulation corresponding with phosphorylation and inactivation of actin severing protein Cofilin, which could explain changes in the cytoskeleton and cellular migration. These results indicate that endometriosis is associated with LINC01133 upregulation, which may affect pathogenesis via the cellular proliferation and migration pathways.

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.

N-cadherin identifies human endometrial epithelial progenitor cells by in vitro stem cell assays

STUDY QUESTION

Is there a specific surface marker that identifies human endometrial epithelial progenitor cells with adult stem cell activity using in vitro assays?

SUMMARY ANSWER

N-cadherin isolates clonogenic, self-renewing human endometrial epithelial progenitor cells with high proliferative potential that differentiate into cytokeratin+ gland-like structures in vitro and identifies their location in some cells of gland profiles predominantly in basalis endometrium adjacent to the myometrium.

WHAT IS KNOWN ALREADY

Human endometrium contains a small population of clonogenic, self-renewing epithelial cells with high proliferative potential that differentiate into large gland-like structures, but their identity and location is unknown. Stage-specific embryonic antigen-1 (SSEA-1) distinguishes the epithelium of basalis from functionalis and is a marker of human post-menopausal (Post-M) endometrial epithelium.

STUDY DESIGN, SIZE, DURATION

Prospective observational study of endometrial epithelial cells obtained from hysterectomy samples taken from 50 pre-menopausal (Pre-M) and 24 Post-M women, of which 4 were from women who had taken daily estradiol valerate 2 mg/day for 8 weeks prior.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Gene profiling was used to identify differentially expressed surface markers between fresh EpCAM (Epithelial Cell Adhesion Molecule)-magnetic bead-selected basalis-like epithelial cells from Post-M endometrium compared with predominantly functionalis epithelial cells from Pre-M endometrium and validated by qRT-PCR. In vitro clonogenicity and self-renewal assays were used to assess the stem/progenitor cell properties of magnetic bead-sorted N-cadherin+ and N-cadherin- epithelial cells. The cellular identity, location and phenotype of N-cadherin+ cells was assessed by dual colour immunofluorescence and confocal microscopy for cytokeratin, proliferative status (Ki-67), ERα, SSEA-1, SOX9 and epithelial mesenchymal transition (EMT) markers on full thickness human endometrium.

MAIN RESULTS AND THE ROLE OF CHANCE

CDH2 (N-cadherin gene) was one of 11 surface molecules highly expressed in Post-M compared to Pre-M endometrial epithelial cells. N-cadherin+ cells comprise a median 16.7% (n = 8) and 20.2% (n = 5) of Pre-M endometrial epithelial cells by flow cytometry and magnetic bead sorting, respectively. N-cadherin+ epithelial cells from Pre-M endometrium were more clonogenic than N-cadherin- cells (n = 12, P = 0.003), underwent more population doublings (n = 7), showed greater capacity for serial cloning (n = 7) and differentiated into cytokeratin+ gland-like organoids. N-cadherin immunolocalised to the lateral and apical membrane of epithelial cells in the bases of glands in the basalis of Pre-M endometrium and Post-M gland profiles, co-expressing cytokeratin, ERα but not SSEA-1 or SOX9, which localized on gland profiles proximal to N-cadherin+ cells. N-cadherin+ cells were quiescent (Ki-67-) in the basalis and in Post-M endometrial glands and co-localized with EMT markers vimentin and E-cadherin.

LARGE SCALE DATA

The raw and processed data files from the gene microarray have been deposited in the National Center for Biotechnology Information Gene Expression Omnibus data set with accession number GSE35221.

LIMITATIONS, REASONS FOR CAUTION

This is a descriptive study in human endometrium only using in vitro stem cell assays. The differential ability of N-cadherin+ and N-cadherin-cells to generate endometrial glands in vivo was not determined. A small number of uterine tissues analysed contained adenomyosis for which N-cadherin has been implicated in epithelial-EMT.

WIDER IMPLICATIONS OF THE FINDINGS

A new marker enriching for human endometrial epithelial progenitor cells identifies a different and potentially more primitive cell population than SSEA-1, suggesting a potential hierarchy of epithelial differentiation in the basalis. Using N-cadherin as a marker, the molecular and cellular characteristics of epithelial progenitor cells and their role in endometrial proliferative disorders including endometriosis, adenomyosis and thin dysfunctional endometrium can be investigated.

STUDY FUNDING/COMPETING INTEREST(S)

This research was supported by Cancer Council Victoria grant 491079 (C.E.G.) and Australian National Health and Medical Research Council grants 1021127 (C.E.G.), 1085435 (C.E.G., J.A.D.), 145780 and 288713 (C.N.S.), RD Wright Career Development Award 465121 (C.E.G.), Senior Research Fellowship 1042298 (C.E.G.), the Victorian Government's Operational Infrastructure Support and an Australian Postgraduate Award (HPTN), and China Council Scholarship (L.X.). The authors have nothing to declare.

Histopathological study of gallbladder carcinoma and its mimics with role of carcinoembryonic antigen immunomarker in resolving diagnostic difficulties

Background:

Gallbladder carcinoma (GBC) sometimes presents with nonspecific signs, without forming a mass, mimicking benign gallbladder (GB) diseases. On the contrary, benign GB diseases may mimic GBC.

Material and Methods:

We retrospectively reviewed 107 cases over a period of 3 years (May 2012–April 2015), which included 41 review cases and 66 departmental cases. Carcinoembryonic antigen (CEA) immunomarker expression was done.

Results:

In 27 of the 41 review cases, the diagnoses were benign diseases of GB associated with mild-to-moderate dysplasia of mucosal glands; however, after review in our department, it was found that of these 27 cases, nine cases were actually well-differentiated adenocarcinoma of GB with diffuse CEA expression and were mis diagnosed as benign diseases of GB with dysplasia. In 32 out of 66 departmental cases, initial histopathological diagnoses were benign diseases of GB associated with dysplastic mucosal glands. After CEA staining, 11 out of these 32 cases turned out to be adenocarcinoma of the GB. Among the rest 34 (34/66) departmental primary GBC cases, no CEA expression was seen in six cases, focal expression was seen in 12 cases, and diffuse expression was seen in 16 cases. No diffuse CEA expression was seen in benign diseases of the GB with dysplasia.

Conclusion:

GBC sometimes may not be diagnosed radiologically and grossly as it often presents without any mass and specific signs, which lead to under diagnosis. Some benign cases may mimic GBC and may complicate histological diagnosis. CEA expression may aid as an additional diagnostic aid in resolving diagnostic dilemmas.

Morphological and immunohistochemical characterization of spontaneous endometriosis in rhesus macaques (Macaca mulatta)

Several cases of spontaneous endometriosis in middle-aged to old rhesus macaques (Macaca mulatta) from the breeding colony of the German Primate Center were thoroughly characterized with regards to anatomical distribution and macroscopic appearance, histological differentiation and immunohistochemical profile including somatic markers, hormonal receptors, and proliferation indices. More than half of the examined animals (five of nine) were directly related to one breeding male, supporting a strong genetic predisposition. Histologically, four different types of endometriotic lesions, depending on the degree of ectopic endometrial gland and stromal differentiation (well differentiated, purely stromal, mixed differentiation, poorly differentiated), could be constantly identified within all animals. Immunohistochemistry (IHC) of cytokeratin (CK), vimentin, smooth muscle actin (SMA), desmin, estrogen (ER), and progesterone (PR) receptors as well as of the nuclear proteins Ki67 and p53 revealed varying staining patterns in the four different types of endometriosis differentiation and compared to normal endometrium. Purely stromal, mixed, or poorly differentiated lesions, especially, showed additional cytokeratin-positive stromal cells, whereas epithelial cells of endometriosis with mixed or poor differentiation increasingly expressed mesenchymal markers (vimentin, SMA). Hormonal receptor and Ki67 expression in well-differentiated endometriotic lesions mostly reflected that of normal endometrial tissue according to the cyclic phase of the animal, while the expression gradually diminished with decreasing grade of differentiation. However, increased nuclear accumulations of p53 antigen could only be continuously detected in epithelial cells of mixed or poorly differentiated endometriosis. Altogether, these findings support the pathogenetic theory of coelomic metaplasia, since the expression profiles of somatic markers in less differentiated forms closely resembled that of mesothelial cells. Thus, the four different histological types of endometriosis might display subsequent grades of differentiation in the course of time, with poorly differentiated types representing newly formed, immature lesions and well-differentiated types being older, fully differentiated forms, rather than being the outcome of dedifferentiation processes.

Effect of S100A6 over-expression on β-catenin in endometriosis

AIM

S100A6 is over-expressed in several human tumors, including pancreatic carcinoma, malignant fibrous histiocytoma, breast, colon, and gastric carcinoma, but little is known about the role of S100A6 in endometriosis. The aim of the present study was to investigate the effect of S100A6 over-expression on β-catenin in endometrial stromal cells.

METHODS

Endometrial stromal cells were transfected with an hS100A6-expressing recombinant lentivirus construct. The expression of β-catenin was assessed using western blot and reverse transcription-polymerase chain reaction.

RESULTS

S100A6 over-expression promoted β-catenin expression at the RNA and protein levels, in endometrial stromal cells.

CONCLUSIONS

S100A6 induces expression of β-catenin in endometrial stromal cells.

Possible involvement of the E-cadherin gene in genetic susceptibility to endometriosis

BACKGROUND

Endometriotic cells display invasive characteristics, despite their benign histological appearance. Recently, the epithelial-mesenchymal transition, in which epithelial cells acquire mesenchymal and migratory properties, has attracted attention as a mechanism of tumor invasion. We aimed to investigate the association between endometriosis and polymorphisms of the E-cadherin gene, a central player in the epithelial-mesenchymal transition, in Japanese women.

METHODS

Twelve single-nucleotide polymorphisms (SNPs) in the E-cadherin gene were identified by real-time polymerase chain reaction using a TaqMan assay in 511 women with endometriosis (the majority in Stages III and IV) and 498 healthy controls.

RESULTS

Allele frequency analysis indicated that there was a marginally higher frequency of the rs4783689 C allele in women with endometriosis compared with controls (corrected P = 0.007; odds ratio = 1.37; 95% confidence interval, 1.14-1.64). No significant associations with endometriosis were found for the other 11 SNPs.

CONCLUSIONS

Although this study was limited by sample size, the E-cadherin gene polymorphism rs4783689 was marginally associated with endometriosis in the Japanese population, suggesting that E-cadherin might be involved in genetic susceptibility to endometriosis.

Epithelial to mesenchymal transition-like and mesenchymal to epithelial transition-like processes might be involved in the pathogenesis of pelvic endometriosis

BACKGROUND

Endometrium is derived from intermediate mesoderm via mesenchymal to epithelial transition (MET) during development of the urogenital system. By retaining some imprint of their mesenchymal origin, endometrial epithelial cells may be particularly prone to return to this state, via epithelial to mesenchymal transition (EMT). We hypothesized that pelvic endometriosis originates from retrograde menstruation of endometrial tissue and that EMT-like and MET-like processes might be involved in the pathogenesis of pelvic endometriosis.

METHODS

We investigated commonly used molecular markers for EMT, including cytokeratin, E-cadherin, N-cadherin, vimentin, S100A4 and dephosphorylated beta-catenin by immunohistochemistry in different forms of pelvic endometriosis: deep infiltrating endometriosis, ovarian endometriosis and superficial peritoneal endometriosis (red and black lesions), as well as samples of menstrual endometrium, other benign ovarian cysts (mucinous and serous cyst adenoma), and abdominal scar endometriosis for comparison.

RESULTS

Epithelial cells of red peritoneal lesions and ovarian endometriosis showed less epithelial marker (cytokeratin, P < 0.0001) expression and more mesenchymal marker (vimentin and/or S100A4, P < 0.0001) expression than those of menstrual endometrium. In contrast, epithelial cells of black peritoneal lesions and deep infiltrating endometriosis showed more epithelial marker (E-cadherin) expression than those of menstrual endometrium (P < 0.03), red peritoneal lesions (P < 0.0001) and ovarian endometriosis (P< 0.0001), but maintained expression of some mesenchymal markers (vimentin, S100A4). In addition, dephosphorylated beta-catenin protein expression was significantly higher in epithelial cells of deep infiltrating endometriosis (P < 0.0001) than in epithelial cells of red and black peritoneal lesions and ovarian endometriosis.

CONCLUSIONS

EMT-like and MET-like processes might be involved in the pathogenesis of pelvic endometriosis.

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.