P-cadherin expression in gastric carcinoma: its regulation mechanism and prognostic significance

Engineering the Interactions of Classical Cadherin Cell-Cell Adhesion Proteins

Classical cadherins are calcium-dependent cell-cell adhesion proteins that play key roles in the formation and maintenance of tissues. Deficiencies in cadherin adhesion are hallmarks of numerous cancers. In this article, we review recent biophysical studies on the regulation of cadherin structure and adhesion. We begin by reviewing distinct cadherin binding conformations, their biophysical properties, and their response to mechanical stimuli. We then describe biophysical guidelines for engineering Abs that can regulate adhesion by either stabilizing or destabilizing cadherin interactions. Finally, we review molecular mechanisms by which cytoplasmic proteins regulate the conformation of cadherin extracellular regions from the inside out.

3D Chromatin Architecture Re-Wiring at the CDH3/CDH1 Loci Contributes to E-Cadherin to P-Cadherin Expression Switch in Gastric Cancer

Cadherins are cell-cell adhesion molecules, fundamental for cell architecture and polarity. E-cadherin to P-cadherin switch can rescue adherens junctions in epithelial tumours. Herein, we disclose a mechanism for E-cadherin to P-cadherin switch in gastric cancers. CDH1 and CDH3 mRNA expression was obtained from 42 gastric tumours' RNA-seq data. CRISPR-Cas9 was used to knock out CDH1 and a putative regulatory element. CDH1-depleted and parental cells were submitted to proteomics and enrichment GO terms analysis; ATAC-seq/4C-seq with a CDH1 promoter viewpoint to assess chromatin accessibility and conformation; and RT-PCR/flow cytometry to assess CDH1/E-cadherin and CDH3/P-cadherin expression. In 42% of gastric tumours analysed, CDH1 to CDH3 switch was observed. CDH1 knockout triggered CDH1/E-cadherin complete loss and CDH3/P-cadherin expression increase at plasma membrane. This switch, likely rescuing adherens junctions, increased cell migration/proliferation, commonly observed in aggressive tumours. E- to P-cadherin switch accompanied increased CDH1 promoter interactions with CDH3-eQTL, absent in normal stomach and parental cells. CDH3-eQTL deletion promotes CDH3/CDH1 reduced expression. These data provide evidence that loss of CDH1/E-cadherin expression alters the CDH3 locus chromatin conformation, allowing a CDH1 promoter interaction with a CDH3-eQTL, and promoting CDH3/P-cadherin expression. These data highlight a novel mechanism triggering E- to P-cadherin switch in gastric cancer.

Mucinous, endometrioid, and serous ovarian cancers with peritoneal dissemination are potent candidates for P-cadherin targeted therapy: a retrospective cohort study

BACKGROUND

Aberrant expression of P-cadherin has been reported in various cancers, and has been attracting attention as a target for cancer treatment. Ovarian cancer, the leading cause of death among gynecologic malignancies, is classified into four histological subtypes: serous, mucinous, endometrioid, and clear cell, and each has distinct biological behavior. Although a negative survival impact in serous ovarian cancer patients and some functional role in peritoneal dissemination have been reported, differences of P-cadherin expression in histological subtypes and the proportion and distribution of positive cells remain to be investigated. The aims of this study were to clarify the histological and distributional profiles of P-cadherin expression in ovarian cancer for development of target-therapy in near future.

METHODS

A total of 162 primary, 60 metastatic, and 8 recurrent tumors (all cases from 162 ovarian cancer patients) were enrolled in the study. Immunohistochemistry was performed for P-cadherin expression. Associations with clinicopathological characteristics and survival were analyzed.

RESULTS

P-cadherin expression showed a strong correlation with the FIGO stage, histological subtypes, positive peritoneal dissemination (P < 0.01), positive distant metastasis (P < 0.05), and trend toward negative overall survival probability (P = 0.050). P-cadherin was intensely and broadly expressed in mucinous, endometrioid, and serous subtypes (P < 0.01). Disseminated tumors demonstrated similar P-cadherin expression to primary tumors whereas metastatic lymph nodes demonstrated significantly decreased expression (P < 0.01).

CONCLUSIONS

Mucinous, endometrioid, and serous ovarian cancer patients accompanied with peritoneal disseminations are the most potent candidates for P-cadherin targeted drug delivery strategies. P-cadherin-targeted therapy may benefit and improve survival of poor-prognosis populations.

Role of Cadherins in Cancer-A Review

Cadherins play an important role in tissue homeostasis, as they are responsible for cell-cell adhesion during embryogenesis, tissue morphogenesis, differentiation and carcinogenesis. Cadherins are inseparably connected with catenins, forming cadherin-catenin complexes, which are crucial for cell-to-cell adherence. Any dysfunction or destabilization of cadherin-catenin complex may result in tumor progression. Epithelial mesenchymal transition (EMT) is a mechanism in which epithelial cadherin (E-cadherin) expression is lost during tumor progression. However, during tumorigenesis, many processes take place, and downregulation of E-cadherin, nuclear β-catenin and p120 catenin (p120) signaling are among the most critical. Additional signaling pathways, such as Receptor tyrosine kinase (RTK), Rho GTPases, phosphoinositide 3-kinase (PI3K) and Hippo affect cadherin cell-cell adhesion and also contribute to tumor progression and metastasis. Many signaling pathways may be activated during tumorigenesis; thus, cadherin-targeting drugs seem to limit the progression of malignant tumor. This review discusses the role of cadherins in selected signaling mechanisms involved in tumor growth. The clinical importance of cadherin will be discussed in cases of human and animal cancers.

Significance of P-cadherin overexpression and possible mechanism of its regulation in intrahepatic cholangiocarcinoma and pancreatic cancer

It has become evident that P-cadherin, one of the classical cadherins, contributes to the malignant behavior of several types of cancer. In this study, we analyzed the expression of P-cadherin and its clinicopathological and prognostic values in intrahepatic cholangiocarcinoma (ICC) and pancreatic cancer. Furthermore, we investigated the functional role of P-cadherin in these cancer cells by knockdown and overexpression in vitro and by analyzing the correlation between the P-cadherin expression and its promoter methylation status. Thirty of 59 ICC cases (51%) and 36 of 73 pancreatic cancer cases (49%) stained positive for P-cadherin with mainly membranous distribution in tumor cells by immunohistochemistry. P-cadherin expression was significantly correlated with several clinicopathological factors, which reflect tumor behavior, and was identified as an independent adverse prognostic factor for disease-free survival in patients with ICC (relative risk [RR] 2.93, P = 0.04) and pancreatic cancer (RR 2.68, P = 0.005) via multivariate analyses. P-cadherin downregulation by siRNA suppressed migration and invasion, and P-cadherin overexpression induced the opposite effects in both ICC and pancreatic cancer cells, without any effects on cell proliferation. P-cadherin expression was related to its promoter methylation status in both cell lines and cancer tissues. In summary, P-cadherin overexpression may serve as a useful biomarker of invasive phenotype and poor prognosis; P-cadherin expression was found to be regulated by its promoter methylation. These results suggest that P-cadherin represents a novel therapeutic target for the treatment of ICC and pancreatic cancer.

Is the ABCB1 gene associated with the increased risk of gastric cancer development?--preliminary research

One of the most common malignant diseases, both worldwide and in Poland, is gastric cancer. The pathogenesis of gastric cancer development is not entirely clear. Next to the environmental risk factors, such as Helicobacter pylori infection or dietary habits, the host genetic factors as predispositions to gastric cancer development are discussed. A transmembrane protein that could be associated with predisposition to cancer development is P-glycoprotein (P-gp). Physiologically, P-gp is present in normal tissue of the gastrointestinal tract, where it plays a protective role by transporting xenobiotics from a cell into extracellular environment. P-gp is encoded by the highly polymorphic ABCB1 gene. The most frequent polymorphisms at positions 1236, 2677, and 3435 may affect both the function and amount of protein, thereby leading to a loss of its physiological function, which could increase the predisposition to development of many diseases, including cancer. In this study, the potential significance of the ABCB1 gene in the development and progression of gastric cancer was evaluated. In 19 tissue samples collected from patients with gastric cancer, the ABCB1 gene polymorphisms were identified at positions 1236 and 2677 by automated sequencing and SNP 3435 by the RFLP method. The relative level of ABCB1 expression was measured in 10 samples of gastric cancer and morphologically normal tissues by real-time PCR. For SNPs at positions 1236, 2677, and 3435, no statistically significant differences in genotype frequencies between gastric cancer patients and healthy individuals were found. However, genotype TT for all studied polymorphisms occurred more frequently in the group of gastric cancer patients (31.6, 26.3, 42.1%, respectively) than in the group of healthy individuals (14.6, 13.5, 21.9%, respectively). The lowest relative expression levels of ABCB1 mRNA were observed for genotypes CC of SNP 1236, CC of SNP 3435, and GG of SNP 2677 (median: 0.215, 0.160, 0.160, respectively). There was a tendency that mutant homozygote TT for SNPs at positions 1236, 2677, and 3435 occurred more frequently in the subgroup of patients with Tis or stage I of TNM classification (SNP 1236 p = 0.0760; SNP 2677 p = 0.0813; SNP 3435 p = 0.0760) than in the subgroup of patients with stage II or III. Also the expression levels were lowest (median 0.740) in the group of patients with the less advanced clinical stage of cancer (Tis or I). Preliminary research showed that the ABCB1 gene polymorphisms at positions 1236, 2677, and 3435 were not related to an increased susceptibility of gastric cancer development. However, they may be associated with the inhibition of gastric cancer progression.

The prognostic value of P-cadherin in non-muscle-invasive bladder cancer

OBJECTIVES

This research aims to specify the prognostic value of P-cadherin on recurrence and progression in non-muscle-invasive bladder cancers (NMIBC).

METHODS

A total of 110 NMIBC cases were collected and P-cadherin protein was assessed by immunohistochemical test in these samples. Correlations between P-cadherin expression and clinicopathologic features were analyzed. For recurrence-free and progression-free survival, Kaplan-Meier log-rank test was used. Then Cox univariate and multivariate analyses were further performed.

RESULTS

P-cadherin high expression correlated with tumor progression (P = 0.031). Kaplan-Meier results showed that patients with high P-cadherin expression had worse progression-free survival (P = 0.034) but not recurrence-free survival (P = 0.133) than low-expression patients. Cox regression results showed P-cadherin expression was an independent predictor for progression (P = 0.042) but not recurrence (P = 0.139) in NMIBC.

CONCLUSIONS

Our results demonstrated that P-cadherin expression correlated with tumor progression and could be taken as an independent predictor for progression in NMIBC.

Research and clinical applications of molecular biomarkers in gastrointestinal carcinoma (Review)

Gastrointestinal (GI) carcinoma is a common malignant disease worldwide. Its development and progression is a multistage process involving a multifactorial etiology. Although the detailed mechanisms of the development of GI carcinoma remain controversial, the elucidation of its molecular biology over the last few years has resulted in a better perspective on its epidemiology, carcinogenesis and pathogenesis. More significantly, it is currently possible to use biological indicators or biomarkers in differential diagnosis, prognostic evaluation and specific clinical interventions. In this review, we aimed to describe the biomarkers of pathogenesis, invasion, metastasis and prognosis of GI carcinoma and discuss their potential clinical applications. The majority of these biomarkers, such as tumor-associated antigens, oncogenes and tumor suppressor genes, metastasis-associated genes, cell adhesion molecules, cytokines, growth factors and microRNAs, are currently broadly applicable.

Down-regulation of P-cadherin with PF-03732010 inhibits cell migration and tumor growth in gastric cancer

P-cadherin is frequently up-regulated in solid tumors such as gastric, colon, lung, pancreatic and breast cancers. Although P-cadherin promotes cadherin-mediated cell adhesion, the gastric cancer-linked regulation of P-cadherin has not been extensively investigated. In this study, we found epigenetic regulation of P-cadherin in human gastric cancer cells that was induced by treatment with DNA demethylating drug and histone deacetylase inhibitor. Silencing P-cadherin by using siRNA induces apoptosis in gastric cells and blocks expression of Tie-2, an angiogenic receptor tyrosine kinase. In contrast, ectopically expressed P-cadherin by generating P-cadherin stable cell line enhances Tie-2 expression and cell mobility. We also demonstrated that inhibition of P-cadherin by PF-03732010, a fully humanized anti-P-cadherin IgG1 monoclonal antibody, suppressed cell migration in vitro and tumor growth in BALB/c nude mice bearing SNU620 gastric cancer xenograft. The data reported here are the first to reveal that the inhibition of P-cadherin decreases tumor cell migration and blocks a tumorigenesis by down-regulation of Tie-2 in gastric cancer. This demonstrates the potential for P-cadherin to be used as a target for treatment of gastric cancer.

Epithelial E- and P-cadherins: role and clinical significance in cancer

E-cadherin and P-cadherin are major contributors to cell-cell adhesion in epithelial tissues, playing pivotal roles in important morphogenetic and differentiation processes during development, and in maintaining integrity and homeostasis in adult tissues. It is now generally accepted that alterations in these two molecules are observed during tumour progression of most carcinomas. Genetic or epigenetic alterations in E- and P-cadherin-encoding genes (CDH1 and CDH3, respectively), or alterations in their proteins expression, often result in tissue disorder, cellular de-differentiation, increased invasiveness of tumour cells and ultimately in metastasis. In this review, we will discuss the major properties of E- and P-cadherin molecules, its regulation in normal tissue, and their alterations and role in cancer, with a specific focus on gastric and breast cancer models.

Gastric cancer: basic aspects

Gastric cancer (GC) is a world health burden, ranging as the second cause of cancer death worldwide. Etiologically, GC arises not only from the combined effects of environmental factors and susceptible genetic variants but also from the accumulation of genetic and epigenetic alterations. In the last years, molecular oncobiology studies brought to light a number of genes that are implicated in gastric carcinogenesis. This review is intended to focus on the recently described basic aspects that play key roles in the process of gastric carcinogenesis. Genetic variants of the genes IL-10, IL-17, MUC1, MUC6, DNMT3B, SMAD4, and SERPINE1 have been reported to modify the risk of developing GC. Several genes have been newly associated with gastric carcinogenesis, both through oncogenic activation (GSK3β, CD133, DSC2, P-Cadherin, CDH17, CD168, CD44, metalloproteinases MMP7 and MMP11, and a subset of miRNAs) and through tumor suppressor gene inactivation mechanisms (TFF1, PDX1, BCL2L10, XRCC, psiTPTE-HERV, HAI-2, GRIK2, and RUNX3). It also addressed the role of the inflammatory mediator cyclooxygenase-2 (COX-2) in the process of gastric carcinogenesis and its importance as a potential molecular target for therapy.

Organomegaly and tumors in transgenic mice with targeted expression of HpaII methyltransferase in smooth muscle cells

Current data suggest that angiogenesis, smooth muscle cell migration, differentiation and proliferation may be epigenetically regulated. Prokaryotic DNA methyltransferases have been proposed as tools to modify mammalian DNA methylation. In order to assess the impact of DNA hypermethylation on smooth muscle pathophysiology, we expressed an HpaII site-specific methyltransferase transgene in smooth muscle cells in mice. The enzyme is expected to target only a subset (CCGG) of unmethylated CpG dinucleotides, thus avoiding possible deleterious effects of widespread hypermethylation. Transgenics of two independent lines were born at expected frequencies, showed no obvious abnormalities and were fertile. Nevertheless, ~30% of > 1 year-old transgenics developed organomegaly and ~20% showed a range of tumors. Global DNA methylation was unchanged in transgenic tissue whether hyperplastic or normal, but tumor DNA showed a pronounced global hypermethylation. DNA hypermethylation was not indiscriminate, as five tested tumor suppressor genes showed promoter CpG and non-CpG hypermethylation and transcriptional down-regulation, whereas the methylation status of one intergenic CpG islands, repeated elements (n=2) and non-tumor suppressor gene promoters (n=3) was unchanged. Our work is the first report on the effects of HpaII methyltransferase on endogenous chromatin and in a whole animal. Furthermore, our data expand previous findings that imply that global DNA hypomethylation is not an obligate oncogenic pathway at least in the tumor types examined here.