Clinical importance and therapeutic implication of E-cadherin gene methylation in human ovarian cancer

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.

Epithelial-mesenchymal interconversions in ovarian cancer: The levels and functions of E-cadherin in intraabdominal dissemination

The metastatic process of ovarian cancer (OC) is almost exclusively defined by direct shedding of tumor cells into the abdominal cavity, followed by clustering into multicellular aggregates and posterior peritoneal anchorage. This process relies on dynamic intercellular interactions which are modified by epithelial- mesenchymal interconversions and, therefore, E-cadherin expression variability. Although widely accepted as a tumor suppressor in many types of cancer, E-cadherin is currently known to have a dynamic expression and a much more complex role in OC. First, high E-cadherin expression is considered a sign of metaplasia in the normal ovarian epithelium, due to its association with epithelial growth factor receptor (EGFR) mediated cell proliferation. Subsequently, it is the decreased expression of E-cadherin that allows the acquisition of a more invasive phenotype, leading to the spread of primary tumor cells into the peritoneal fluid. This downregulation seems to depend on complex regulatory mechanisms, from molecular proteolysis to microenvironment interference and epigenetic regulation. E-cadherin cleavage and its resulting fragments appear to be essential to the process of dissemination and even to the formation of multicellular aggregates. Paradoxically, the maintenance of some E-cadherin expression seems to promote intercellular adhesion, resistance, and survival while decreasing cancer response to chemotherapy. Multiple studies have shown that reversing epithelial-mesenchymal transaction (EMT) and increasing E-cadherin expression prevents OC intraperitoneal dissemination, but findings that simultaneously correlate E-cadherin downregulation to higher chemotherapy sensitivity should not be ignored. Nevertheless, EMT and E-cadherin seem to have a potential interest as therapeutic targets in novel approaches to OC treatment.

Aberrant Methylation Status of Tumour Suppressor Genes in Ovarian Cancer Tissue and Paired Plasma Samples

Ovarian cancer is a highly heterogeneous disease and its formation is affected by many epidemiological factors. It has typical lack of early signs and symptoms, and almost 70% of ovarian cancers are diagnosed in advanced stages. Robust, early and non-invasive ovarian cancer diagnosis will certainly be beneficial. Herein we analysed the regulatory sequence methylation profiles of the RASSF1, PTEN, CDH1 and PAX1 tumour suppressor genes by pyrosequencing in healthy, benign and malignant ovarian tissues, and corresponding plasma samples. We recorded statistically significant higher methylation levels (p < 0.05) in the CDH1 and PAX1 genes in malignant tissues than in controls (39.06 ± 18.78 versus 24.22 ± 6.93; 13.55 ± 10.65 versus 5.73 ± 2.19). Higher values in the CDH1 gene were also found in plasma samples (22.25 ± 14.13 versus 46.42 ± 20.91). A similar methylation pattern with positive correlation between plasma and benign lesions was noted in the CDH1 gene (r = 0.886, p = 0.019) and malignant lesions in the PAX1 gene (r = 0.771, p < 0.001). The random forest algorithm combining methylation indices of all four genes and age determined 0.932 AUC (area under the receiver operating characteristic (ROC) curve) prediction power in the model classifying malignant lesions and controls. Our study results indicate the effects of methylation changes in ovarian cancer development and suggest that the CDH1 gene is a potential candidate for non-invasive diagnosis of ovarian cancer.

The role of GRHL2 and epigenetic remodeling in epithelial-mesenchymal plasticity in ovarian cancer cells

Cancer cells exhibit phenotypic plasticity during epithelial-mesenchymal transition (EMT) and mesenchymal-epithelial transition (MET) involving intermediate states. To study genome-wide epigenetic remodeling associated with EMT plasticity, we integrate the analyses of DNA methylation, ChIP-sequencing of five histone marks (H3K4me1, H3K4me3, H3K27Ac, H3K27me3 and H3K9me3) and transcriptome profiling performed on ovarian cancer cells with different epithelial/mesenchymal states and on a knockdown model of EMT suppressor Grainyhead-like 2 (GRHL2). We have identified differentially methylated CpG sites associated with EMT, found at promoters of epithelial genes and GRHL2 binding sites. GRHL2 knockdown results in CpG methylation gain and nucleosomal remodeling (reduction in permissive marks H3K4me3 and H3K27ac; elevated repressive mark H3K27me3), resembling the changes observed across progressive EMT states. Epigenetic-modifying agents such as 5-azacitidine, GSK126 and mocetinostat further reveal cell state-dependent plasticity upon GRHL2 overexpression. Overall, we demonstrate that epithelial genes are subject to epigenetic control during intermediate phases of EMT/MET involving GRHL2.

Chronic cadmium exposure aggravates malignant phenotypes of nasopharyngeal carcinoma by activating the Wnt/β-catenin signaling pathway via hypermethylation of the casein kinase 1α promoter

BACKGROUND

Our previous study has shown that cadmium (Cd) exposure is not only a risk factor for nasopharyngeal carcinoma (NPC), but also correlated with the clinical stage and lymph node metastasis. However, the underlying molecular events of Cd involved in NPC progression remain to be elucidated.

PURPOSE

The objective of this study was to decipher how Cd impacts the malignant phenotypes of NPC cells.

METHODS

NPC cell lines CNE-1 and CNE-2 were continuously exposed with 1 μM Cd chloride for 10 weeks, designating as chronic Cd treated NPC cells (CCT-NPC). MTT assay, colony formation assay and xenograft tumor growth were used to assess cell viability in vitro and in vivo. Transwell assays were performed to detect cell invasion and migration. The protein levels of E-cadherin, N-cadherin, Vimentin as well as β-catenin and casein kinase 1α(CK1α) were measured by Western blot. Immunofluorescence staining was used to observe the distribution of filament actin (F-actin), β-catenin and CK1α. The mRNA levels of downstream target genes of β-catenin were detected by RT-PCR. Wnt/β-catenin signaling activity was assessed by TOPFlash/FOPFlash dual luciferase report system. MS-PCR was used to detect the methylation status of CK1α. Finally, the activation of Wnt/β-catenin pathway and cell biological properties were examined following treatment of CCT-NPC cells with 5-aza-2-deoxy-cytidine(5-aza-CdR).

RESULTS

CCT-NPC cells showed an increase in cell proliferation, colony formation, invasion and migration compared to the parental cells. Cd also induced cytoskeleton reorganization and epithelial-to-mesenchymal transition. Upregulation and nuclear translocation of β-catenin and increased luciferase activity accompanied with transcription of downstream target genes were found in CCT-NPC cells. Treatment of CCT-CNE1 cells with 5-aza-CdR could reverse the hypermethylation of CK1α and attenuate the cell malignancy.

CONCLUSION

These results support a role for chronic Cd exposure as a driving force for the malignant progression of NPC via epigenetic activation of the Wnt/β-catenin pathway.

Transmembrane protease, serine 4 (TMPRSS4) is upregulated in IPF lungs and increases the fibrotic response in bleomycin-induced lung injury

Idiopathic pulmonary fibrosis (IPF) is a chronic and progressive lung disease characterized by epithelial cell activation, expansion of the fibroblast population and excessive extracellular matrix accumulation. The mechanisms are incompletely understood but evidence indicates that the deregulation of several proteases contributes to its pathogenesis. Transmembrane protease serine 4 (TMPRSS4) is a novel type II transmembrane serine protease that may promote migration and facilitate epithelial to mesenchymal transition (EMT), two critical processes in the pathogenesis of IPF. Thus, we hypothesized that over-expression of TMPRSS4 in the lung could promote the initiation and/or progression of IPF. In this study we first evaluated the expression and localization of TMPRSS4 in IPF lungs by real time PCR, western blot and immunohistochemistry. Then we examined the lung fibrotic response in wild-type and TMPRSS4 deficient mice using the bleomycin-induced lung injury model. We found that this protease is upregulated in IPF lungs, where was primarily expressed by epithelial and mast cells. Paralleling the findings in vivo, TMPRSS4 was expressed by alveolar and bronchial epithelial cells in vitro and unexpectedly, provoked an increase of E-cadherin. No expression was observed in normal human or IPF lung fibroblasts. The lung fibrotic response evaluated at 28 days after bleomycin injury was markedly attenuated in the haplodeficient and deficient TMPRSS4 mice. By morphology, a significant reduction of the fibrotic index was observed in KO and heterozygous mice which was confirmed by measurement of collagen content (hydroxyproline: WT: 164±21.1 μg/lung versus TMPRSS4 haploinsufficient: 110.2±14.3 μg/lung and TMPRSS4 deficient mice: 114.1±24.2 μg/lung (p<0.01). As in IPF, TMPRSS4 was also expressed in epithelial and mast cells. These findings indicate that TMPRSS4 is upregulated in IPF lungs and that may have a profibrotic role.

CDH4 suppresses the progression of salivary adenoid cystic carcinoma via E-cadherin co-expression

The cadherin-4 gene (CDH4) of the cadherin family encodes non-epithelial R-cadherin (R-cad); however, the function of this gene in different types of cancer remains controversial. In this study, we found higher expression of CDH4 mRNA in a salivary adenoid cystic carcinoma (SACC) cell line with low metastatic potential (SACC-83) than in a cell line with high metastatic potential (SACC-LM). By analyzing 67 samples of SACC tissues and 40 samples of paraneoplastic normal tissues, we found R-cad highly expressed in 100% of normal paraneoplastic tissue but only expressed in 64% of SACC tumor tissues (P<0.001). Knockdown of CDH4 expression in vitro promoted the growth, mobility and invasion of SACC cells, and in vivo experiments showed that decreased CDH4 expression enhanced SACC tumorigenicity. Furthermore, CDH4 suppression resulted in down-regulation of E-cadherin (E-cad), which is encoded by CDH1 gene and is a well-known tumor suppressor gene by inhibition of cell proliferation and migration. These results indicate that CDH4 may play a negative role in the growth and metastasis of SACC via co-expression with E-cadherin.

Downregulated Expression of E-cadherin and TP53 in Patients with Gastric Diseases: the Involvement of H. pylori Infection and Its Virulence Markers

PURPOSE

Gastritis caused by infection with Helicobacter pylori is characterized by chronic inflammation and damage in gastric tissue, which is a main risk factor for gastric cancer. Associated with H. pylori, the TP53 gene tumor suppressor and the cell adhesion glycoprotein epithelial cadherin develop a relevant role in the integrity and carcinogenesis of the epithelium. We aimed to detection of H. pylori and its main virulence markers and measured the messenger RNA (mRNA) expression levels of E-cadherin and TP53 genes.

METHODS

The detection of H. pylori and its virulence markers, as well as the mRNA expression levels of E-cadherin and TP53 genes, were obtained for 161 samples of gastric biopsies including 37 with normal gastric tissue, 70 with gastritis, 24 from neoplastic tissue, and 27 from adjacent non-neoplastic by means of a quantitative real-time polymerase chain reaction.

RESULTS

The mRNA expression levels of E-cadherin and TP53 were found to be decreased in patients with gastritis, independently of H. pylori infection. In samples from gastric patients, the neoplastic tissue showed an accentuated decrease of expression; on the other hand, the expression of E-cadherin was normal in adjacent non-neoplastic.

CONCLUSIONS

No evidence was found of the involvement of the cagA and vacA genes in the decreased expression of E-cadherin and TP53. The process of carcinogenesis is complex, and the decrease of the E-cadherin gene expression and TP53 gene expression appears to contribute significantly.

The association between CDH1 promoter methylation and patients with ovarian cancer: a systematic meta-analysis

Background

The down-regulation of E-cadherin gene (CDH1) expression has been regarded as an important event in cancer invasion and metastasis. However, the association between CDH1 promoter methylation and ovarian cancer remains unclear. A meta-analysis was conducted to evaluate the potential role of CDH1 promoter methylation in ovarian cancer.

Methods

Relevant articles were identified by searches of PubMed, EMBASE, Cochrane Library, CNKI and Wanfang databases. The pooled odds ratio (OR) and corresponding 95 % confidence interval (CI) were calculated to assess the strength of association.

Results

Nine studies were performed using the fixed-effects model in this study, including 485 cancer tissues and 255 nonmalignant tissues. The findings showed that CDH1 promoter methylation had an increased risk of ovarian cancer in cancer tissues (OR = 8.71, P < 0.001) in comparison with nonmalignant tissues. Subgroup analysis of the ethnicity showed that the OR value of CDH1 methylation in Asian population subgroup (OR = 13.20, P < 0.001) was higher than that in Caucasian population subgroup (OR = 3.84, P = 0.005). No significant association was found between ovarian cancer and low malignant potential (LMP) tumor (P = 0.096) among 2 studies, and between CDH1 promoter methylation and tumor stage and tumor histology (all P > 0.05). There was not any evidence of publication bias by Egger’s test (all P > 0.05).

Conclusions

CDH1 promoter methylation can be a potential biomarker in ovarian cancer risk prediction, especially Asians can be more susceptible to CDH1 methylation. However, more studies are still done in the future.

The clinicopathological significance and potential drug target of E-cadherin in NSCLC

Human epithelial cadherin (E-cadherin), a member of transmembrane glycoprotein family, encoded by the E-cadherin gene, plays a key role in cell-cell adhesion, adherent junction in normal epithelial tissues, contributing to tissue differentiation and homeostasis. Although previous studies indicated that inactivation of the E-cadherin is mainly induced by hypermethylation of E-cadherin gene, evidence concerning E-cadherin hypermethylation in the carcinogenesis and development of non-small cell lung carcinoma (NSCLC) remains controversial. In this study, we conducted a meta-analysis to quantitatively evaluate the effects of E-cadherin hypermethylation on the incidence and clinicopathological characteristics of NSCLC. A comprehensive search of PubMed and Embase databases was performed up to October 2014. Analyses of pooled data were performed. Odds ratios (ORs) were calculated and summarized. Our meta-analysis combining 18 published articles demonstrated that the hypermethylation frequencies in NSCLC were significantly higher than those in normal control tissues, OR = 3.55, 95 % confidence interval (CI) = 1.98-6.36, p < 0.0001. Further analysis showed that E-cadherin hypermethylation was not strongly associated with the sex or smoking status in NSCLC patients. In addition, E-cadherin hypermethylation was also not strongly associated with pathological types, differentiated status, clinical stages, or metastatic status in NSCLC patients. The results from the current study indicate that the hypermethylation frequency of E-cadherin in NSCLC is strongly associated with NSCLC incidence and it may be an early event in carcinogenesis of NSCLC. We also discussed the potential value of E-cadherin as a drug target that may bring new direction and hope for cancer treatment through gene-targeted therapy.