E‐cadherin interactions are required for Langerhans cell differentiation

Human skin contains the following two distinct DC subsets: (i) Langerhans cells (LCs), expressing Langerin but not DC‐specific intercellular adhesion molecule‐3‐grabbing nonintegrin (DC‐SIGN), are predominantly localized in the epidermis; and (ii) dermal DCs, expressing DC‐SIGN but not Langerin, are observed mainly in the dermis. It is not known whether localization in the epidermis provides cues for LC differentiation. Here, we show that E‐cadherin expressed by epidermal keratinocytes (KCs) is crucial for differentiation of LCs. Monocytes differentiated into LC‐like cells in presence of IL‐4, GM‐CSF, and TGF‐β1. However, these LC‐like cells expressed not only Langerin but also DC‐SIGN. Notably, co‐culturing of these LC‐like cells with KCs expressing E‐cadherin or recombinant E‐cadherin strongly decreased expression of DC‐SIGN and further induced a phenotype similar to purified epidermal LCs. Moreover, pretreatment of LC‐like cells with anti‐E‐cadherin‐specific antibody completely abolished their Langerin expression, indicating the requirement of E‐cadherin–E‐cadherin interactions for the differentiation into Langerin⁺ cells. These findings suggest that E‐cadherin expressed by KCs provide environmental cues that induce differentiation of LCs in the epidermis.     

Interaction of KLRG1 with E‐cadherin: New functional and structural insights

The killer cell lectin‐like receptor G1 (KLRG1) is an inhibitory receptor expressed by memory T cells and NK cells in man and mice. It is frequently used as a cell differentiation marker and members of the cadherin family are ligands for KLRG1. The present study provides new insights into the interaction of mouse KLRG1 with E‐cadherin. Firstly, we demonstrate that co‐engagement of KLRG1 and CD3/TCR in a spatially linked manner was required for inhibition arguing against the notion that KLRG1‐ligation per se transmits inhibitory signals. Secondly, experiments with T cells carrying Y₇F‐mutant KLRG1 molecules with a replacement of the tyrosine residue to phenylalanine in the single ITIM indicated that the inhibitory activity of KLRG1 is counteracted to some degree by increased interaction of KLRG1⁺ T cells with E‐cadherin expressing target cells. Thirdly, we demonstrate that deletion of the first or the second external domain of E‐cadherin abolished reactivity in KLRG1‐reporter cell assays. Finally, we made the intriguing observation that KLRG1 formed multimeric protein complexes in T cells in addition to the previously described mono‐ and dimeric molecules.     

Changes in E‐ and N‐cadherin expression in developing rat adenohypophysis

Recently, we showed that hormone‐producing cells express N‐cadherin, while folliculo‐stellate cells and marginal layer cells express E‐cadherin in the adult rat anterior pituitary gland. These cells are believed to originate from a single cell population of the adenohypophyseal placode. In the present study, we immunohistochemically examined the divergence of cadherin types during pituitary histogenesis. Pituitary glands were excised from rats of embryonic day 11 (E11) through postnatal day 60 (P60) and paraffin sections were prepared. E‐ and N‐cadherins were immunostained sequentially using monoclonal and polyclonal primary antibodies and fluorescent secondary antibodies. At E11, E‐cadherin was expressed over oral epithelium, while N‐cadherin expression was limited to the primordium of Rathke's pouch. When Rathke's pouch was formed at E13, E‐ and N‐cadherin were broadly expressed in the entire cell population. N‐cadherin was expressed particularly intensely in the layer of cells that faced the lumen. From E14 through E16, the majority of cells expressed both types of cadherins; however, the cell population to become the pars tuberalis expressed N‐cadherin but not E‐cadherin. From E18 through E20, when many hormone‐producing cells appear, the number of cells that expressed N‐cadherin alone increased. However, some cell populations in the pars distalis and multilayered marginal cells still expressed both cadherins. After birth, most of the cells came to express only one of the cadherin types. These results may suggest that undetermined adenohypophyseal cells express both E‐ and N‐cadherin, but come to express either E‐ or N‐cadherin during cytogenesis. Anat Rec, 2007. © 2007 Wiley‐Liss, Inc.     

Immunohistochemical analysis of the expression of E‐cadherin and ZEB1 in non‐small cell lung cancer

We performed an immunohistochemical analysis of the expression of zinc‐finger E‐box binding homeobox 1 (ZEB1), a master regulator of epithelial‐mesenchymal transition (EMT), and determined its relationship with E‐cadherin in 157 non‐small cell lung carcinomas (93 adenocarcinomas, 36 squamous cell carcinomas, 18 large cell carcinomas, and 10 pleomorphic carcinomas). Although the expression of E‐cadherin was low in the subset of adenocarcinomas (10%) and squamous cell carcinomas (11%), ZEB1 expression was only observed in one case of squamous cell carcinoma and none of the adenocarcinomas. In contrast, the low expression of E‐cadherin (50% and 90%, respectively) and the positive expression of ZEB1 (11% and 50%, respectively) were more frequently observed in poorly differentiated carcinomas (large cell carcinomas and pleomorphic carcinomas). Overall, the expression of ZEB1 was inversely correlated with that of E‐cadherin. Furthermore, the distribution of ZEB1‐positive cancer cells was more restricted than in the area in which the expression of E‐cadherin was lost, and the former was detected within the latter. We concluded that the expression of ZEB1 was not necessarily associated with the low expression of E‐cadherin in lung adenocarcinomas and squamous cell carcinomas. The expression of ZEB1 correlated with an undifferentiated and/or sarcomatoid morphology that may occur in the late stage of EMT.     

Homo- and heterotypic cell-cell contacts in Merkel cells and Merkel cell carcinomas: heterogeneity and indications for cadherin switching

Werling A M, Doerflinger Y, Brandner J M, Fuchs F, Becker J C, Schrama D, Kurzen H, Goerdt S & Peitsch W K
(2011) Histopathology 58, 286–303
Homo‐ and heterotypic cell–cell contacts in Merkel cells and Merkel cell carcinomas: heterogeneity and indications for cadherin switching Aims: Merkel cell carcinomas (MCCs) are rare but aggressive tumours associated recently with Merkel cell polyomavirus (MCV). As development and progression of several types of carcinomas can be promoted by changes in cell adhesion proteins, the aim of this study was to examine homo‐ and heterotypic cell contacts of Merkel cells and MCCs. Methods and results: Merkel cells of healthy glabrous epidermis and 52 MCCs were analysed by double‐label immunostaining, immunofluorescence and confocal microscopy. Merkel cells were connected to keratinocytes by E‐ and P‐cadherin, desmoglein 2 and desmocollin 2. In contrast, the vast majority of MCCs (90%) contained N‐cadherin, but only 67% and 65% contained E‐ and P‐cadherin, respectively. Interestingly, P‐cadherin was absent significantly more frequently in lymph node metastases than in primary tumours and by trend in more advanced clinical stages. Moreover, major subsets of MCCs synthesized desmoglein 2 and, surprisingly, tight junction proteins. No significant differences were observed upon stratification for MCV DNA, detected in 84% of tumours by real‐time polymerase chain reaction. Conclusions: Assuming that MCCs originate from Merkel cells, our data indicate a switch from E‐ and P‐cadherin to N‐cadherin during tumorigenesis. Whether the unexpected heterogeneity of junctional proteins can be exploited for prognostic and therapeutic purposes will need to be examined.     

Stromal CD10 expression and relationship to the E‐cadherin/β‐catenin complex in breast carcinoma

Kim H‐S, Kim G Y, Kim Y W, Park Y‐K, Song J‐Y & Lim S‐J
(2010) Histopathology 56, 708–719
Stromal CD10 expression and relationship to the E‐cadherin/β‐catenin complex in breast carcinoma Aims: Previous investigations have indicated that stromal CD10 expression, and altered levels of both E‐cadherin and β‐catenin, are associated with the biological aggressiveness of human carcinoma. The aim was to evaluate stromal CD10 expression and the association of stromal CD10 with E‐cadherin and β‐catenin in breast carcinoma. Methods and results: The expression of CD10, E‐cadherin and β‐catenin was immunohistochemically analysed in tissue microarrays containing 104 cases of invasive ductal carcinoma (IDC) and 10 cases of ductal carcinoma in situ (DCIS). Stromal CD10 was detected in 49.5% (50/101) of the IDC. No immunoreactivity was identified in the stromal cells of normal breast, DCIS or intraductal components of IDC. Accumulation of the cytoplasmic β‐catenin was found in 87.0% (87/100) of the IDC. Stromal CD10 expression in IDC was significantly correlated with tumour size (P = 0.027), stage (P < 0.001) and histological grade (P = 0.006), the presence of nodal (P = 0.048) and distant (P = 0.015) metastases, oestrogen receptor‐negative status (P = 0.016), cytoplasmic β‐catenin accumulation (P = 0.031) and lower overall survival rate (P = 0.041). Conclusions: Stromal CD10 expression in IDC may constitute an important prognostic marker. Stromal CD10 expression with associated aggressive features might be related to aberrant β‐catenin expression.     

Prognostic significance of single isolated cells with decreased E‐cadherin expression in pseudomyxoma peritonei

Pseudomyxoma peritonei (PMP) cases can be classified into the prognosis‐related subtypes of disseminated peritoneal adenomucinosis (DPAM) and peritoneal mucinous carcinomatosis (PMCA). To investigate the mechanisms of mucinous invasion and the differing prognoses of these two subtypes, we examined the expression levels of proteins involved in cellular adhesion and invasion, including E‐cadherin, vimentin, β‐catenin, and S100A4, in single isolated tumor cells (SICs) and cohesive cellular strips within mucin pools isolated from DPAM (n = 31) and PMCA (n = 21) patients. In both PMCA and DPAM cases, SICs showed a complete loss of E‐cadherin expression, whereas cells in cohesive cellular clusters retained E‐cadherin expression. The frequency of high numbers of SICs (>8) in PMCA cases was significantly greater than that in DPAM cases (86% and 26%, respectively) and was correlated with poor progression‐free survival (P = 0.019) in a univariate analysis. In both PMP subtypes, strong vimentin expression was identified in most of the SICs but not the cohesive cellular strips. The relatively slow progression of DPAM may be attributable to the smaller number of SICs that lack E‐cadherin expression and have increased vimentin expression, whereas the rapid progression of PMCA may be due to larger numbers of these SICs.     

Catenin‐δ1, negatively regulated by miR‐145, promotes tumour aggressiveness in gastric cancer

Increasing evidence supports the association of catenin‐δ1 (CTNND1, p120ctn) with tumour development and progression. However, the mechanism and clinical significance of CTNND1 deregulation in gastric cancer remain unknown. The expression level and cellular localization of CTNND1 were determined by immunohistochemistry in 126 human gastric cancer and 50 non‐tumourous tissues. The cellular localization of CTNND1 and epithelial cadherin (E‐cadherin) were detected by immunofluorescence. Cell proliferation, apoptosis, migration and invasion assays were performed to assess the effect of CTNND1 cDNA or CTNND1 siRNA transfection on gastric cancer cells. Luciferase assay, western blot analysis and in vivo assays were used to determine whether CTNND1 could be regulated by miR‐145. The results demonstrate that the cytoplasmic localization of CTNND1 protein, rather than expression level, was indicative of higher clinical stage, positive lymph node metastasis and poorer prognosis in gastric cancers. CTNND1 could promote gastric cancer cell migration and invasion with little effect on cellular proliferation and apoptosis. CTNND1 was proved to be a direct target gene for miR‐145. Besides suppressing cytoplasmic CTNND1 expression, miR‐145 could recover the membranous localization of CTNND1 and E‐cadherin. We conclude that cytoplasmic CTNND1 can serve as an independent prognostic factor for patients with gastric cancers. MiR‐145 inhibits invasion of gastric cancer cells not only by down‐regulating cytoplasmic CTNND1 expression but also by inducing the translocation of CTNND1 and E‐cadherin from the cytoplasm to the cell membrane through down‐regulating N‐cadherin. Copyright © 2014 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.     

E‐cadherin germline mutations define an inherited cancer syndrome dominated by diffuse gastric cancer

To extend earlier observations of germline E‐cadherin mutations in kindreds with an inherited susceptibility to diffuse gastric cancer, we searched for germline E‐cadherin mutations in five further families affected predominantly by diffuse gastric cancer and one family with a history of diffuse gastric cancer and early‐onset breast cancer. Heterozygous inactivating mutations were found in the E‐cadherin gene in each of these families. No mutation hotspots were identified. These results demonstrate that germline mutation of the E‐cadherin gene is a common cause of hereditary diffuse gastric cancer and suggest a role for these mutations in the incidence of breast cancer. Hum Mutat 14:249–255, 1999. © 1999 Wiley‐Liss, Inc.     

Slug regulates E‐cadherin expression in metastatic adenocarcinoma cells isolated from pleural fluid

Slug protein is a key regulator of epithelial‐mesenchymal transition, but its expression in cancer is less well studied. To evaluate the expression of slug, E‐cadherin and vimentin in adenocarcinoma cells from malignant pleural effusions, we analyzed 121 malignant pleural fluid specimens. Twenty‐eight nonmalignant pleural fluid specimens were analyzed as control. Besides clinical cytological diagnosis tests, immunofluorescence, immunocytochemistry and Western blotting methods were used. Results showed strong membrane staining of E‐cadherin in adenocarcinoma cells from pleural fluid. Slug mainly showed nucleus staining. Cytoplasma positive of vimentin was found in adenocarcinoma cells isolated from pleural fluid. Slug, E‐cadherin and vimentin expression was found in 43/121 (36%), 87/121 (72%) and 102/121 (84%) cases, respectively. Our data showed elevated levels of slug were accompanied by down regulation of E‐cadherin and the expression of vimentin in adenocarcinoma cells. In addition, there was no relationship between slug expression and patient's age or gender or tumor site. Hyperplasia epithelium cells from nonmalignant pleural fluid were uniformly negative for E‐cadherin and slug. In conclusion, the results demonstrated the inverse expression of slug and E‐cadherin in the majority of malignant pleural fluid cases compared with nonmalignant pleural fluid. The slug protein may be helpful to access the prognosis of patients with pleural fluid. Diagn. Cytopathol. 2013. © 2011 Wiley Periodicals, Inc.     

Switch of cadherin expression as a diagnostic tool for Leydig cell tumours

Leydig cell tumours comprise about 3% of all testicular tumours. The pathogenesis of Leydig cell tumours is still poorly understood. We investigated testis with Leydig cell hyperplasia and Leydig cell tumours for their expression pattern of P‐ and N‐cadherin. We could show a switch of expression of P‐ and N‐cadherin in Leydig cell hyperplasia and Leydig cell tumours in comparison with normal Leydig cells. Cadherins could be established as a new immunohistochemical marker for this testicular tumour entity; their possible role in tumour genesis will be discussed.     

αE‐catenin is a candidate tumor suppressor for the development of E‐cadherin‐expressing lobular‐type breast cancer

Although mutational inactivation of E‐cadherin (CDH1) is the main driver of invasive lobular breast cancer (ILC), approximately 10–15% of all ILCs retain membrane‐localized E‐cadherin despite the presence of an apparent non‐cohesive and invasive lobular growth pattern. Given that ILC is dependent on constitutive actomyosin contraction for tumor development and progression, we used a combination of cell systems and in vivo experiments to investigate the consequences of α‐catenin (CTNNA1) loss in the regulation of anchorage independence of non‐invasive breast carcinoma. We found that inactivating somatic CTNNA1 mutations in human breast cancer correlated with lobular and mixed ducto‐lobular phenotypes. Further, inducible loss of α‐catenin in mouse and human E‐cadherin‐expressing breast cancer cells led to atypical localization of E‐cadherin, a rounded cell morphology, and anoikis resistance. Pharmacological inhibition experiments subsequently revealed that, similar to E‐cadherin‐mutant ILC, anoikis resistance induced by α‐catenin loss was dependent on Rho/Rock‐dependent actomyosin contractility. Finally, using a transplantation‐based conditional mouse model, we demonstrate that inducible inactivation of α‐catenin instigates acquisition of lobular features and invasive behavior. We therefore suggest that α‐catenin represents a bona fide tumor suppressor for the development of lobular‐type breast cancer and as such provides an alternative event to E‐cadherin inactivation, adherens junction (AJ) dysfunction, and subsequent constitutive actomyosin contraction. © 2018 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.     

E‐cadherin immunohistochemistry in breast pathology: uses and pitfalls

E‐cadherin immunohistochemistry is used commonly in surgical pathology practice to help distinguish lobular carcinoma in situ from ductal carcinoma in situ and invasive lobular carcinoma from invasive ductal carcinoma in histologically problematic or indeterminate cases. However, the interpretation of E‐cadherin immunostains is not always straightforward. Failure to recognize the pitfalls and limitations of E‐cadherin immunostains can lead to an erroneous diagnosis which may result in inappropriate patient management, particularly for patients with in‐situ lesions. In this paper we review the uses and, particularly, the pitfalls in the interpretation of E‐cadherin immunostains in distinguishing lobular from ductal lesions of the breast.