Biological relevance of E-cadherin-catenin complex proteins in primary epithelial ovarian tumours

E-Cadherin Expression in Relation to Clinicopathological Parameters and Survival of Patients with Epithelial Ovarian Cancer

It is generally accepted that loss/reduction of E-cadherin expression on tumor cells promotes their migration, invasiveness, and metastasis. It is also an indicator of cancer cells' aggressiveness. The aim of this study was to assess how the expression of E-cadherin varies in primary ovarian cancer tissue in regard to overall survival of patients; FIGO stage; grade; histopathological type of tumor; and potential factors discriminating malignant and nonmalignant ovarian tumors. Our analysis was based on literature research (1 January 2000-8 November 2021) conducted according to the PRISMA guidelines. Most studies support the assumption that loss/reduced expression of E-cadherin results in shorter overall survival of EOC patients. Moreover, most research has shown that there is a correlation between the low level of E-cadherin and the advancement stage of disease, especially in high-grade serous ovarian carcinoma type. However, E-cadherin expression seems to not be helpful to distinguish malignant and nonmalignant tumors. In conclusion, reduced E-cadherin expression in primary ovarian cancer tissue may indicate a less favorable disease outcome and is associated with high advancement of the disease.

Glucocorticoids induce differentiation and chemoresistance in ovarian cancer by promoting ROR1-mediated stemness

Glucocorticoids are routinely used in the clinic as anti-inflammatory and immunosuppressive agents as well as adjuvants during cancer treatment to mitigate the undesirable side effects of chemotherapy. However, recent studies have indicated that glucocorticoids may negatively impact the efficacy of chemotherapy by promoting tumor cell survival, heterogeneity, and metastasis. Here, we show that dexamethasone induces upregulation of ROR1 expression in ovarian cancer (OC), including platinum-resistant OC. Increased ROR1 expression resulted in elevated RhoA, YAP/TAZ, and BMI-1 levels in a panel of OC cell lines as well as primary ovarian cancer patient-derived cells, underlining the translational relevance of our studies. Importantly, dexamethasone induced differentiation of OC patient-derived cells ex vivo according to their molecular subtype and the phenotypic expression of cell differentiation markers. High-throughput drug testing with 528 emerging and clinical oncology compounds of OC cell lines and patient-derived cells revealed that dexamethasone treatment increased the sensitivity to several AKT/PI3K targeted kinase inhibitors, while significantly decreasing the efficacy of chemotherapeutics such as taxanes, as well as anti-apoptotic compounds such as SMAC mimetics. On the other hand, targeting ROR1 expression increased the efficacy of taxane drugs and SMAC mimetics, suggesting new combinatorial targeted treatments for patients with OC.

Dependence and Guidance Receptors-DCC and Neogenin-In Partial EMT and the Actions of Serine Proteases

The Epithelial-Mesenchymal Transition (EMT) is an important concept in understanding the processes of oncogenesis, especially with respect to the relationship between cell proliferation and metastatic properties such as spontaneous cell motility, chemotaxic migration and tissue invasion. EMT is now recognized as a more complex phenomenon than an all-or-nothing event, in which different components of the EMT may have distinct roles in the physio-pathological regulation of cell function and which may in turn depend on differential interactions with cell constituents and metabolic products. This mini-review summarizes recent work on the induction of cancer properties in parallel with the presence of EMT activities in the presence of serine proteases, with the focus on those tumor suppressors known as “dependence” receptors such as neogenin and Deleted in Colorectal Cancer (DCC). It is concluded that various forms of partial EMT should be given more detailed investigation and consideration as the results could have valuable implications for the development of disease-specific and patient-specific therapies.

Serine protease modulation of Dependence Receptors and EMT protein expression

Expression of the tumour suppressor Deleted in Colorectal Cancer (DCC) and the related protein neogenin is reduced by the mammalian serine protease chymotrypsin or the bacterial serine protease subtilisin, with increased cell migration. The present work examines whether these actions are associated with changes in the expression of cadherins, β-catenin and vimentin, established markers of the Epithelial-Mesenchymal Transition (EMT) which has been linked with cell migration and tumour metastasis. The results confirm the depletion of DCC and neogenin and show that chymotrypsin and subtilisin also reduce expression of β-catenin in acutely prepared tissue sections but not in human mammary adenocarcinoma MCF-7 or MDA-MB-231 cells cultured in normal media, or primary normal human breast cells. A loss of β-catenin was also seen in low serum media but transfecting cells with a dcc-containing plasmid induced resistance. E-cadherin was not consistently affected but vimentin was induced by low serum-containing media and was increased by serine proteases in MCF-7 and MDA-MB-231 cells in parallel with increased wound closure. Vimentin might contribute to the promotion of cell migration. The results suggest that changes in EMT proteins depend on the cells or tissues concerned and do not parallel the expression of DCC and neogenin. The increased cell migration induced by serine proteases is not consistently associated with the expression of the EMT proteins implying either that the increased migration may be independent of EMT or supporting the view that EMT is not itself consistently related to migration. (241).

Prognostic significance of β-catenin expression in patients with ovarian cancer: A meta-analysis

AIM

The purpose of this study was to evaluate the impact of β-catenin immunohistochemical expression on the prognostic of ovarian cancer (OC) for that β-catenin could be responsible for the development and progress of OC.

METHODS

We searched various databases to identify eligible studies, and Review Managers 5.2 software was fulfilled in the meta-analysis.

RESULTS

A total of 11 studies were defined and composed in 1858 cases. β-catenin expression was significantly correlated with poor overall survival (OS) in OC patients (HR: 2.48, 95% CI: 1.38-4.47, P = 0.003), and showed a significant degree of heterogeneity (I² = 83%, P < 0.00001). Subgroup analysis indicated that accumulation in the nucleus and/or cytoplasm, rather than membrane, considerably influences the survival of OC patients independently.

CONCLUSION

Nucleus and/or cytoplasma of β-catenin expression might be associated with tumor progression and could be a possible potential predictive factor of poor prognosis in OC patients.

Genome-wide analysis of DNA Methylation profiles on sheep ovaries associated with prolificacy using whole-genome Bisulfite sequencing

Background

Ovulation rate and litter size are important reproductive traits in sheep with high economic value. Recent work has revealed a potential link between DNA methylation and prolificacy. However, a genome-wide study that sought to identify potential DNA methylation sites involved in sheep prolificacy indicated that it is still unknown. Here, we aimed to investigate the genome-wide DNA methylation profiles of Hu sheep ovaries by comparing a high-prolificacy group (HP, litter size of three for at least 2 consecutive lambings) and low prolificacy group (LP, litter size of one for at least 2 consecutive lambings) using deep whole-genome bisulfite sequencing (WGBS).

Results

First, our results demonstrated lower expression levels of DNA methyltransferase (DNMT) genes in the ovaries of the HP group than that in the ovaries of the LP group. Both groups showed similar proportions of methylation at CpG sites but different proportions at non-CpG sites. Subsequently, we identified 70,899 differential methylated regions (DMRs) of CG, 16 DMRs of CHG, 356 DMRs of CHH and 12,832 DMR-related genes(DMGs). Gene Ontology (GO) analyses revealed that some DMGs were involved in regulating female gonad development and ovarian follicle development. Finally, we found that 10 DMGs, including BMP7, BMPR1B, CTNNB1, FST, FSHR, LHCGR, TGFB2 and TGFB3, are more likely to be involved in prolificacy of Hu sheep, as assessed by correlation analysis and listed in detail.

Conclusions

This study revealed the global DNA methylation pattern of sheep ovaries associated with high and low prolificacy groups, which may contribute to a better understanding of the epigenetic regulation of sheep reproductive capacity.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-017-4068-9) contains supplementary material, which is available to authorized users.

Alternatively spliced protein arginine methyltransferase 1 isoform PRMT1v2 promotes the survival and invasiveness of breast cancer cells

Protein arginine methylation is catalyzed by protein arginine methyltransferases (PRMTs) and plays an important role in many cellular processes. Aberrant PRMT expression has been observed in several common cancer types; however, their precise contribution to the cell transformation process is not well understood. We previously reported that the PRMT1 gene generates several alternatively spliced isoforms, and our initial biochemical characterization of these isoforms revealed that they exhibit distinct substrate specificity and subcellular localization. We focus here on the PRMT1v2 isoform, which is the only predominantly cytoplasmic isoform, and we have found that its relative expression is increased in breast cancer cell lines and tumors. Specific depletion of PRMT1v2 using RNA interference caused a significant decrease in cancer cell survival due to an induction of apoptosis. Furthermore, depletion of PRMT1v2 in an aggressive cancer cell line significantly decreased cell invasion. We also demonstrate that PRMT1v2 overexpression in a non-aggressive cancer cell line was sufficient to render them more invasive. Importantly, this novel activity is specific to PRMT1v2, as overexpression of other isoforms did not enhance invasion. Moreover, this activity requires both proper subcellular localization and methylase activity. Lastly, PRMT1v2 overexpression altered cell morphology and reduced cell-cell adhesion, a phenomenon that we convincingly linked with reduced β-catenin protein expression. Overall, we demonstrate a specific role for PRMT1v2 in breast cancer cell survival and invasion, underscoring the importance of identifying and characterizing the distinct functional differences between PRMT1 isoforms.

Colorectal adenocarcinoma: a pediatric case review with a focus on mismatch repair gene mutations and E-cadherin expression

Colorectal adenocarcinoma (CRAC) is exceedingly rare in the pediatric population (fewer than 2 cases per 1 million children). There are 2 major categories of pediatric colorectal adenocarcinoma syndromes: polyposis-related and hereditary nonpolyposis colorectal cancer, also known as Lynch syndrome. Germ line mutations in DNA mismatch repair (MMR) genes (eg, MLH1, MSH2, PMS2, MSH6) have been established as the molecular genetic basis of Lynch syndrome. Another prognostic factor in adult CRAC is the reduced expression of epithelial cadherin (E-cadherin), which has been associated with poor outcome in some adult CRAC cases; however, its role in predicting prognoses in pediatric cases remains unclear. Seven pediatric patients with primary CRAC were reviewed. Available molecular genetic test results were evaluated, and immunohistochemical labeling for MMR proteins and E-cadherin were performed on 5 patients. Four of the 5 patients in our study with available paraffin blocks showed loss of MMR protein expression, consistent with Lynch syndrome. In cases stained for E-cadherin, 3 were strongly positive and 2 were weakly positive; however, with the small sample size and the relatively short follow-up period, an accurate correlation between E-cadherin and prognosis cannot be reached with any degree of certainty. Our findings highlight the importance of genetic testing for MMR gene mutations in children with colorectal cancer and suggest further investigation into the prognostic role of E-cadherin in pediatric CRAC.

E-cadherin nuclear staining is useful for the diagnosis of ovarian adult granulosa cell tumor

We recently have demonstrated nuclear localization of E-cadherin in ovarian adult granulosa cell tumors (Histopathology 2011;58:423). The purpose of the present study is to investigate the diagnostic utility of E-cadherin nuclear staining for the differential diagnosis between ovarian adult granulosa cell tumor and its morphological mimics. Tissue samples taken from 81 ovarian tumors and 20 extraovarian tumors were immunohistochemically stained using monoclonal anti-E-cadherin antibody recognizing cytoplasmic domain (clone 36 supplied by BD Biosciences, San Jose, CA). The ovarian tumors consisted of 30 adult granulosa cell tumors, 3 Sertoli-stromal cell tumors, 14 fibrothecomas, 5 carcinoid tumors, 1 large cell neuroendocrine carcinoma, 18 endometrioid adenocarcinomas, and 10 poorly differentiated serous adenocarcinomas. Extraovarian tumors consisted of 16 uterine endometrial stromal neoplasms and 4 pulmonary small cell carcinomas. Only tumor cells with nuclear staining were considered positive in this study. Ninety percent of adult granulosa cell tumors, 67% of Sertoli-stromal cell tumors, 64% of fibrothecomas, 75% of endometrial stromal neoplasms, 75% of small cell carcinomas, and the one large cell neuroendocrine carcinoma showed E-cadherin nuclear expression, whereas all the ovarian carcinoid tumors, endometrioid adenocarcinomas, and poorly differentiated serous adenocarcinomas were negative. E-cadherin nuclear staining is useful in distinguishing between adult granulosa cell tumors and ovarian adenocarcinomas or carcinoid tumors. However, it is of limited use for distinguishing between adult granulosa cell tumors and endometrial stromal neoplasms or small cell carcinomas. E-cadherin should be included in the immunohistochemical panel for an accurate diagnosis of ovarian adult granulosa cell tumors.

EZH2 supports ovarian carcinoma cell invasion and/or metastasis via regulation of TGF-beta1 and is a predictor of outcome in ovarian carcinoma patients

It was suggested that the enhancer of zeste homolog 2 (EZH2) gene is a putative candidate oncogene in several types of human cancer. The potential oncogenic role of EZH2 and its clinical/prognostic significance, however, in ovarian carcinoma are unclear. In this study, EZH2 expression was examined by immunohistochemistry (IHC) in cohorts of normal and tumorous ovarian tissues. High expression of EZH2 was examined in none of the normal ovaries, in 3% of the cystadenomas, in 23% of the borderline tumors and in 50% of the ovarian carcinomas, respectively. In the ovarian carcinomas, high expression of EZH2 was positively correlated with an ascending histological grade and/or advanced stage of the disease (P < 0.05). Moreover, high expression of EZH2 in ovarian carcinoma was determined to be a strong and an independent predictor of short overall survival (P < 0.05). In ovarian carcinoma HO-8910 and UACC-326 cell lines, EZH2 knockdown by RNA interference led to a G(1) phase cell cycle arrest, reduced cell growth/proliferation and inhibited cell migration and/or invasion in vitro. In addition, EZH2 knockdown was found to reduce transforming growth factor-beta1 (TGF-beta1) expression and increase E-cadherin expression either in the transcript or in the protein levels. Furthermore, a significant positive correlation between overexpression of EZH2 and TGF-beta1 in ovarian carcinoma tissues was observed (P < 0.001). These findings suggest a potential important role of EZH2 in the control of cell migration and/or invasion via the regulation of TGF-beta1 expression, and the high expression of EZH2, as detected by IHC, is an independent molecular marker for shortened survival time of patients with ovarian carcinoma.

Wnt signaling in ovarian tumorigenesis

Data are emerging implicating Wnt signaling in ovarian tumorigenesis. We sought to review the current literature on the subject and discuss the pathway's potential role as a prognostic marker and therapeutic target. We conducted a systematic literature review of studies investigating the association between Wnt signaling and ovarian cancer. Search strategies included online searching of the MEDLINE database and hand searching of relevant publications and reviews. Additional reports were collected by systematically reviewing all references from retrieved papers. Twenty-nine papers were identified that directly investigate Wnt signaling and ovarian cancer. Mutations in the CTNNB1 gene that codes for beta-catenin, the key effector in the pathway, are directly linked to carcinogenic transformation but are mostly found in ovarian endometrioid adenocarcinomas, a histologic subtype of epithelial ovarian cancer. These mutations, along with others, lead to deregulation of the pathway and transcription of target genes. Differences in various intra- and extracellular components of the Wnt pathway have been demonstrated between normal ovarian and cancer cell lines and between benign tissue and ovarian cancer. These differences implicate Wnt signaling in the molecular events that lead to ovarian cancer development despite the fact that gene mutations are uncommon. The data suggest that Wnt signaling plays a role in ovarian tumorigenesis. The exact mechanisms by which this occurs need to be further elucidated. Wnt signaling is probably involved via multiple, diverse mechanisms. Further research in this area is warranted.

Antisense suppression of pygopus2 results in growth arrest of epithelial ovarian cancer

PURPOSE

The Pygopus proteins are critical elements of the canonical Wnt/beta-catenin transcriptional complex. In epithelial ovarian cancer, constitutively active Wnt signaling is restricted to one (endometrioid) tumor subtype. The purpose of this study was to determine the level of expression and growth requirements of human Pygopus2 (hPygo2) protein in epithelial ovarian cancer.

EXPERIMENTAL DESIGN

Expression and subcellular localization of hPygo2 was determined in epithelial ovarian cancer cell lines and tumors using Northern blot, immunoblot, and immunofluorescence. Immunohistochemistry was done on 125 archived patient epithelial ovarian cancer tumors representing all epithelial ovarian cancer subtypes. T-cell factor-dependent transcription levels were determined in epithelial ovarian cancer cells using TOPflash/FOPflash in vivo assays. Phosphorothioated antisense oligonucleotides were transfected into cell lines and growth assayed by cell counting, anchorage-independent colony formation on soft agar, and xenografting into severe combined immunodeficient mice.

RESULTS

All six epithelial ovarian cancer cell lines and 82% of the patient samples overexpressed nuclear hPygo2 compared with control cells and benign disease. Depletion of hPygo2 by antisense oligonucleotides in both Wnt-active (TOV-112D) and Wnt-inactive serous (OVCAR-3, SKOV-3) and clear cell (TOV-21G) carcinoma cell lines halted growth, assessed using tissue culture, anchorage-independent, and xenograft assays.

CONCLUSIONS

hPygo2 is unexpectedly widely expressed in, and required in the absence of, Wnt signaling for malignant growth of epithelial ovarian cancer, the deadliest gynecologic malignancy. These findings strongly suggest that inhibition of hPygo2 may be of therapeutic benefit for treating this disease.

Clinical evaluation of E-cadherin expression and its regulation mechanism in epithelial ovarian cancer

E-cadherin plays an important role in maintaining tissue architecture. Loss of E-cadherin expression has often been associated with cancer metastasis. This study assessed the immuno-expression of E-cadherin and methylation of CDH1 and correlated them with clinical features in primary epithelial ovarian cancer. Moreover, epithelial ovarian cancer cell SKOV3 was used to explore the mechanism how the demethylating agent 5-Aza inhibited cancer metastasis. Of 80 patients with primary ovarian cancer, we found that decreased immunoexpression pattern of E-cadherin was associated with clinical stage, lymph node metastasis, and degree of differentiation. Methylation of CDH1 detected by MSP occurred frequently and was correlated with reduced expression of E-cadherin protein. 5-Aza treatment could lead to re-expression of functional E-cadherin, followed by decreased MMP-2 and MMP-9 activity and inhibition of cell invasion in SKOV3 cells. Therefore, we conclude that assessment of E-cadherin immunoreactivity or methylation of CDH1 may be a useful prognostic indicator in ovarian cancer, complementary to established prognostic factors. The mechanism underlying 5-Aza's anti-metastasis activity is associated with restored functional expression of E-cadherin and decreased MMPs activity. Correction of aberrant DNA methylation by 5-Aza may provide a new strategy for ovarian cancer prevention and therapy.