E-cadherin and gastric cancer: cause, consequence, and applications. Biomed Res Int. 2014;2014:637308. [PMID: 25184143 PMCID: PMC4145387 DOI: 10.1155/2014/637308]

Inhibitory effects of Lactobacillus reuteri strain I300 against Helicobacter pylori adhesion, invasion, and inflammatory response in gastric epithelial cells in vitro

The increasing rate of Helicobacter pylori (H. pylori) antibiotic resistance has attenuated the effectiveness of conventional antibiotic-based treatment regimens. This study was aimed at investigating the in vitro inhibitory effects of Lactobacillus reuteri (L. reuteri) strain I300 against H. pylori. The inhibitory effects of live L. reuteri I300 and its different formulations I300L, I300G, and I300T were examined on H. pylori adhesion and invasion to AGS cells. Auto-aggregation and co-aggregation assays and also scanning electron microscopy were performed, evaluating L. reuteri capacity to auto-aggregate and co-aggregate with H. pylori. RT-qPCR and ELISA were used to investigate the expression, and production level of inflammation-related cytokines TNF-α, IL-8, and IL-10. E-cadherin expression level was also measured, determining L. reuteri potential effect on AGS cells integrity. L. reuteri presented a time-dependent capacity to auto-aggregate and co-aggregate with H. pylori. Live L. reuteri and its formulations significantly reduced H. pylori adhesion and invasion of AGS cells. H. pylori treatment with L. reuteri reduced proinflammatory cytokines TNF-α and IL-8 production while increasing anti-inflammatory cytokine IL-10 production. L. reuteri promoted the epithelial cell-cell contact by upregulating E-cadherin expression. This study indicated L. reuteri I300 as a potential probiotic strain with co-aggregation capacity and inhibitory effects against H. pylori adhesion, invasion, and inflammation.

DNMT1 promotes the proliferation and migration of gastric cancer cells by inducing microRNA-125a-5p methylation to promote SERPINE1 protein

BACKGROUND

Gastric cancer (GC) is a malignant tumor originating from gastric mucosal epithelial cells that has high morbidity and mortality. microRNAs (miR) are important diagnostic markers and therapeutic targets in this disease.

AIM

To explore the mechanism of miR-125a-5p in the pathogenesis of GC.

METHODS

The expression levels of miR-125a-5p, SERPINE1 and DNMT1 in GC cells and tissues were detected by real-time polymerase chain reaction (PCR) and Western blotting. Methylation-specific PCR was used to detect the level of miR-125a-5p methylation. A cell counting kit 8 assay, scratch test, and a Transwell assay were performed to detect the proliferation, migration, and invasiveness of HGC27 cells, respectively. The expression of the epithelial mesenchymal transition (EMT)-related proteins E-cadherin, N-cadherin and vimentin in HGC27 cells was detected by Western blotting, while the expression of vimentin was detected by immunofluorescence.

RESULTS

This study revealed that miR-125a-5p was expressed at low levels in GC clinical samples and cells and that miR-125a-5p overexpression inhibited the proliferation, migration, invasiveness and EMT of GC cells. Mechanistically, miR-125a-5p can reduce GC cell proliferation, promote E-cadherin expression, inhibit N-cadherin and vimentin expression, and reduce the EMT of GC cells, thus constraining GC cells to a certain extent. Moreover, DNMT1 inhibited miR-125a-5p expression by increasing the methylation of the miR-125a-5p promoter, thereby promoting the expression of SERPINE1, which acts together with miR-125a-5p to exert antagonistic effects on GC.

CONCLUSION

Our study revealed that DNMT1 promoted SERPINE1 protein expression by inducing miR-125a-5p methylation, which led to the proliferation, migration and occurrence of EMT in GC cells.

Advancing gastric cancer treatment: nanotechnology innovations and future prospects

Gastric cancer (GC) is the fifth most common cancer worldwide, particularly prevalent in Asia, especially in China, where both its incidence and mortality rates are significantly high. Meanwhile, nanotechnology has demonstrated great potential in the treatment of GC. In particular, nanodrug delivery systems have improved therapeutic efficacy and targeting through various functional modifications, such as targeting peptides, tumor microenvironment responsiveness, and instrument-based methods. For instance, silica (SiO2) has excellent biocompatibility and can be used as a drug carrier, with its porous structure enhancing drug loading capacity. Polymer nanoparticles regulate drug release rates and mechanisms by altering material composition and preparation methods. Lipid nanoparticles efficiently encapsulate hydrophilic drugs and promote cellular uptake, while carbon-based nanoparticles can be used in biosensors and drug delivery. Targets such as integrins, HER2 receptors, and the tumor microenvironment have been used to improve drug efficacy in GC treatment. Nanodrug delivery techniques not only enhance drug efficacy and delivery capabilities but also selectively target tumor cells. Currently, there is a lack of systematic summarization and synthesis regarding the relationship between nanodrug delivery systems and GC treatment, which to some extent hinders researchers and clinicians from efficiently searching for and referencing related studies, thereby reducing work efficiency. This study aims to systematically summarize the existing research on the relationship between nanodrug delivery systems and GC treatment, making it easier for professionals to search and reference, and thereby promoting further research on the role of nanodrug delivery systems and their clinical applications in GC. This review discusses the applications of functionalized nanocarriers in the treatment of GC in recent years, including surface modifications with targeted markers, the combination of phototherapy, chemotherapy, and immunotherapy, along with their advantages and challenges. It also examines the future prospects of targeted nanomaterials in GC treatment. The review particularly focuses on the combined application of nanocarriers in multiple treatment modalities, such as phototherapy, chemotherapy, and immunotherapy, demonstrating their potential in multimodal treatments. Furthermore, it thoroughly explores the specific challenges that nanocarriers face in GC treatment, such as biocompatibility, drug release control, and clinical translation issues, while providing a systematic outlook on future developments. Additionally, this study emphasizes the potential value and feasibility of nanocarriers in clinical applications, contrasting with most reviews that focus on basic research. Through these innovations, we offer new perspectives and directions for the development of nanotechnology in the treatment of GC.

HtrA-Dependent E-Cadherin Shedding Impairs the Epithelial Barrier Function in Primary Gastric Epithelial Cells and Gastric Organoids

Impaired E-cadherin (Cdh1) functions are closely associated with cellular dedifferentiation, infiltrative tumor growth and metastasis, particularly in gastric cancer. The class-I carcinogen Helicobacter pylori (H. pylori) colonizes gastric epithelial cells and induces Cdh1 shedding, which is primarily mediated by the secreted bacterial protease high temperature requirement A (HtrA). In this study, we used human primary epithelial cell lines derived from gastroids and mucosoids from different healthy donors to investigate HtrA-mediated Cdh1 cleavage and the subsequent impact on bacterial pathogenesis in a non-neoplastic context. We found a severe impairment of Cdh1 functions by HtrA-induced ectodomain cleavage in 2D primary cells and mucosoids. Since mucosoids exhibit an intact apico-basal polarity, we investigated bacterial transmigration across the monolayer, which was partially depolarized by HtrA, as indicated by microscopy, the analyses of the transepithelial electrical resistance (TEER) and colony forming unit (cfu) assays. Finally, we investigated CagA injection and observed efficient CagA translocation and tyrosine phosphorylation in 2D primary cells and, to a lesser extent, similar effects in mucosoids. In summary, HtrA is a crucially important factor promoting the multistep pathogenesis of H. pylori in non-transformed primary gastric epithelial cells and organoid-based epithelial models.

Molecular Classifications in Gastric Cancer: A Call for Interdisciplinary Collaboration

Gastric cancer (GC) is a heterogeneous disease, often diagnosed at advanced stages, with a 5-year survival rate of approximately 20%. Despite notable technological advancements in cancer research over the past decades, their impact on GC management and outcomes has been limited. Numerous molecular alterations have been identified in GC, leading to various molecular classifications, such as those developed by The Cancer Genome Atlas (TCGA) and the Asian Cancer Research Group (ACRG). Other authors have proposed alternative perspectives, including immune, proteomic, or epigenetic-based classifications. However, molecular stratification has not yet transitioned into clinical practice for GC, and little attention has been paid to alternative molecular classifications. In this review, we explore diverse molecular classifications in GC from a practical point of view, emphasizing their relationships with clinicopathological factors, prognosis, and therapeutic approaches. We have focused on classifications beyond those of TCGA and the ACRG, which have been less extensively reviewed previously. Additionally, we discuss the challenges that must be overcome to ensure their impact on patient treatment and prognosis. This review aims to serve as a practical framework to understand the molecular landscape of GC, facilitate the development of consensus molecular categories, and guide the design of innovative molecular studies in the field.

Predictive Factors Associated with Survival in Female Gastric Cancer Patients in Southeast Asia

Introduction

Association of Southeast Asian Nations (ASEAN) countries have high Helicobacter pylori infections, and gastric cancer (GC) is a leading fatal cancer in this region, especially in female patients. This study aimed to compare clinical manifestations, histopathological subtypes, and prognostic factors associated with the overall survival rate of female GC patients in this important region.

Methods

This retrospective cohort study was conducted between 2007 and 2022 at a tertiary care center in Thailand. All clinical information, endoscopic findings, and histological types were extensively reviewed. Furthermore, all qualified studies in ASEAN published in PubMed and Scopus between 2000 and 2022 were extracted and thoroughly analyzed. Young female GC patients are defined as those ≤50 years of age.

Results

A total of 98 Thai female GC patients were included, with a mean age of 58.99 ± 14 years; 70.4% were elderly women. The common presenting symptoms were weight loss (69.4%) and dyspepsia (68.4%). Younger female GC patients had significantly more common diffuse-type GC than elderly female GC patients (82.8% vs. 53.6%, p-value = 0.007). Moreover, elderly female GC patients demonstrated significantly better survival than younger female GC patients (44.8% vs. 20.7%, odds ratio = 3.49; 95% confidence interval: 1.20-10.14, p-value = 0.022). Furthermore, a total of 1,491 female GC patients from ASEAN were reviewed and included in this study, aged 15 to 93 years. The top three countries with the highest proportion of female GC from ASEAN were Indonesia (66.7%), Thailand (44.9%), and Singapore (38.4%).

Conclusion

GC in women is not uncommon in ASEAN and presents at an advanced stage with a grave prognosis. This study showed that ASEAN countries with the highest disease burden were Indonesia, Thailand, and Singapore. Overall, survival rates for female GC patients in ASEAN countries were relatively low, highlighting the need for proactive measures such as intensive H. pylori eradication and the development of early detection methods for GC.

Upregulation of E-cadherin by the combination of methionine restriction and HDAC2 intervention for inhibiting gastric carcinoma metastasis

Invasion and metastasis are the leading causes of death in individuals with malignant tumors, including gastric cancer. In this study, we aim to explore the effect and related mechanisms of methionine restriction (MR) on gastric carcinoma metastasis. In the MR cell model, gastric carcinoma cells are cultured in the MR medium, and in the animal model, BALB/c nude rodents are administered with a methionine-free diet after receiving injections of MKN45 cells into the caudal vein. Transwell assay is used to detect cell invasion and migration. Chromatin immunoprecipitation is performed to investigate the levels of H3K9me2, H3K27Ac, and H3K27me3 in the E-cadherin promoter. The results show that MR inhibits gastric carcinoma cell migration, invasion, and lung metastasis. MR increases E-cadherin while reducing the H3K27me3 level in the E-cadherin promoter. E-cadherin expression in gastric carcinoma cells is adversely regulated by HDAC2. Overexpressing HDAC2 reduces the H3K27Ac level in the E-cadherin promoter, while interfering with HDAC2 increases the H3K27Ac level. HDAC2 interference under MR conditions further upregulates E-cadherin expression and inhibits gastric carcinoma cell migration, invasion, and lung metastasis. MR combined with HDAC2 interference promotes E-cadherin expression by mediating the methylation and acetylation of E-cadherin, thus inhibiting the invasion, migration, and lung metastasis of gastric carcinoma cells. Our study provides a new theoretical basis for the inhibitory effect of MR on gastric cancer.

The Importance of Th2 Immune Responses in Mediating the Progression of Gastritis-Associated Metaplasia to Gastric Cancer

Gastric cancer is one of the leading causes of cancer deaths worldwide, with chronic gastritis representing the main predisposing factor initiating the cascade of events leading to metaplasia and eventually progressing to cancer. A widely accepted classification distinguishes between autoimmune and environmental atrophic gastritis, mediated, respectively, by T cells promoting the destruction of the oxyntic mucosa, and chronic H. pylori infection, which has also been identified as the major risk factor for gastric cancer. The original dogma posits Th1 immunity as a main causal factor for developing gastritis and metaplasia. Recently, however, it has become evident that Th2 immune responses play a major role in the events causing chronic inflammation leading to tumorigenesis, and in this context, many different cell types and cytokines are involved. In particular, the activity of cytokines, such as IL-33 and IL-13, and cell types, such as mast cells, M2 macrophages and eosinophils, are intertwined in the process, promoting chronic gastritis-dependent and more diffuse metaplasia. Herein, we provide an overview of the critical events driving the pathology of this disease, focusing on the most recent findings regarding the importance of Th2 immunity in gastritis and gastric metaplasia.

Gastric Carcinoma with low ROR alpha, low E- Cadherin and High LAPTM4B Immunohistochemical Profile; is associated with unfavorable prognosis in Egyptian patients

In view of multiplicity of carcinogenic pathways of gastric carcinoma (GC), poor survival and chemotherapy resistance, more analysis of these pathways is required for prediction of prognosis and developing new therapeutic targets. Knocking down of RORα; induces tumor cell proliferation and epithelial-mesenchymal transition (EMT). LAPTM4B has been suggested to be associated with EMT which promote tumor invasion. This work aimed to investigate prognostic role of RORα, LAPTM4B, and E-Cadherin expression in GC. This retrospective immunohistochemical study assesses the expression of RORα, LAPTM4B, and E-Cadherin in 73 primary gastric carcinomas. Low RORα and high LAPTM4B expression in GC cases were associated with unfavorable prognostic factors such as positive lymph nodes, and high tumor budding. E-Cadherin heterogeneous staining was associated with poor prognostic criteria, such as diffuse type GC and high tumor budding. Low RORα, high LAPTM4B, and heterogeneous E-Cadherin were the most common immunohistochemical profile in GC cases. Low RORα expression showed poor prognostic impact on overall patient survival. In conclusion, RORα and LAPTM4B may have crucial role in GC aggressiveness. The predominance of low RORα, high LAPTM4B, and heterogeneous or negative E-Cadherin immunohistochemical profile in GC cases with unfavorable pathological parameters suggested that this profile may predict tumor behavior.

The roles EpCAM plays to enhance the malignancy of gastric cancer

BACKGROUND

Gastric cancer (GC) remains a global challenge due to its high morbidity and mortality rates especially in Asia as well as poor response to treatment. As a member of the adhesion protein family and transmembrane glycoprotein, EpCAM expressed excessively in cancer cells including GC cells. The database assay showed that EpCAM is excessively expressed and easily mutated in cancers, especially in early stage of GC.

METHODS

To explore the roles EpCAM plays in oncogenesis and progression of GC, the expression of EpCAM was deleted in GC cells with CRISPR/Cas9 method, and then the changes of cell proliferation, apoptosis, motility and motility associated microstructures in EpCAM-deleted GC cells (EpCAM-/-SGC7901) were detected to evaluate the rules EpCAM played.

RESULTS

The results showed that EpCAM deletion caused cell proliferation, motility and the development of motility-relevant microstructures inhibited significantly, apoptotic trend and contact inhibition enhanced in EpCAM-deleted GC cells. The results of western blot suggested that EpCAM modulates the expression of epithelial/endothelial mesenchymal transition (EMT) correlated genes. All results as above indicated that EpCAM plays important roles to enhance the oncogenesis, malignancy and progression as a GC enhancer.

CONCLUSIONS

Combining our results and published data together, the interaction of EpCAM with other proteins was also discussed and concluded in the discussion. Our results support that EpCAM can be considered as a novel target for the diagnosis and therapy of GC in future.

The global prevalence of gastric cancer in Helicobacter pylori-infected individuals: a systematic review and meta-analysis

BACKGROUND

Helicobacter pylori is a gastrointestinal pathogen that infects around half of the world's population. H. pylori infection is the most severe known risk factor for gastric cancer (GC), which is the second highest cause of cancer-related deaths globally. We conducted a systematic review and meta-analysis to assess the global prevalence of GC in H. pylori-infected individuals.

METHODS

We performed a systematic search of the PubMed, Web of Science, and Embase databases for studies of the prevalence of GC in H. pylori-infected individuals published from 1 January 2011 to 20 April 2021. Metaprop package were used to calculate the pooled prevalence with 95% confidence interval. Random-effects model was applied to estimate the pooled prevalence. We also quantified it with the I2 index. Based on the Higgins classification approach, I2 values above 0.7 were determined as high heterogeneity.

RESULTS

Among 17,438 reports screened, we assessed 1053 full-text articles for eligibility; 149 were included in the final analysis, comprising data from 32 countries. The highest and lowest prevalence was observed in America (pooled prevalence: 18.06%; 95% CI: 16.48 - 19.63; I2: 98.84%) and Africa (pooled prevalence: 9.52%; 95% CI: 5.92 - 13.12; I2: 88.39%). Among individual countries, Japan had the highest pooled prevalence of GC in H. pylori positive patients (Prevalence: 90.90%:95% CI: 83.61-95.14), whereas Sweden had the lowest prevalence (Prevalence: 0.07%; 95% CI: 0.06-0.09). The highest and lowest prevalence was observed in prospective case series (pooled prevalence: 23.13%; 95% CI: 20.41 - 25.85; I2: 97.70%) and retrospective cohort (pooled prevalence: 1.17%; 95% CI: 0.55 - 1.78; I 2: 0.10%).

CONCLUSIONS

H. pylori infection in GC patients varied between regions in this systematic review and meta-analysis. We observed that large amounts of GCs in developed countries are associated with H. pylori. Using these data, regional initiatives can be taken to prevent and eradicate H. pylori worldwide, thus reducing its complications.

The putative pleiotropic functions of meprin β in gastric cancer

BACKGROUND

The gastric microbiome and inflammation play a key role in gastric cancer (GC) by regulating the immune response in a complex manner and by inflammatory events supporting carcinogenesis. Meprin β is a zinc endopeptidase and participates in tissue homeostasis, intestinal barrier function and immunological processes. It influences local inflammatory processes, dysbiosis and the microbiome. Here, we tested the hypothesis that meprin β is expressed in GC and of tumor biological significance.

PATIENTS AND METHODS

Four hundred forty whole mount tissue sections of patients with therapy-naive GC were stained with an anti-meprin β antibody. The histoscore and staining pattern were analyzed for each case. Following dichotomization at the median histoscore into a "low" and "high" group, the expression was correlated with numerous clinicopathological patient characteristics.

RESULTS

Meprin β was found intracellularly and at the cell membrane of GC. Cytoplasmic expression correlated with the phenotype according to Lauren, microsatellite instability and PD-L1 status. Membranous expression correlated with intestinal phenotype, mucin-1-, E-cadherin-, β-catenin status, mucin typus, microsatellite instability, KRAS mutation and PD-L1-positivity. Patients with cytoplasmic expression of meprin β showed a better overall and tumor-specific survival.

CONCLUSIONS

Meprin β is differentially expressed in GC and has potential tumor biological relevance. It might function as a tumor suppressor or promotor depending on histoanatomical site and context.

Identification and validation of biomarkers for epithelial-mesenchymal transition-related cells to estimate the prognosis and immune microenvironment in primary gastric cancer by the integrated analysis of single-cell and bulk RNA sequencing data

BACKGROUND

The epithelial-mesenchymal transition (EMT) is associated with gastric cancer (GC) progression and immune microenvironment. To better understand the heterogeneity underlying EMT, we integrated single-cell RNA-sequencing (scRNA-seq) data and bulk sequencing data from GC patients to evaluate the prognostic utility of biomarkers for EMT-related cells (ERCs), namely, cancer-associated fibroblasts (CAFs) and epithelial cells (ECs).

METHODS

scRNA-seq data from primary GC tumor samples were obtained from the Gene Expression Omnibus (GEO) database to identify ERC marker genes. Bulk GC datasets from the Cancer Genome Atlas (TCGA) and GEO were used as training and validation sets, respectively. Differentially expressed markers were identified from the TCGA database. Univariate Cox, least-absolute shrinkage, and selection operator regression analyses were performed to identify EMT-related cell-prognostic genes (ERCPGs). Kaplan-Meier, Cox regression, and receiver-operating characteristic (ROC) curve analyses were adopted to evaluate the prognostic utility of the ERCPG signature. An ERCPG-based nomogram was constructed by integrating independent prognostic factors. Finally, we evaluated the correlations between the ERCPG signature and immune-cell infiltration and verified the expression of ERCPG prognostic signature genes by in vitro cellular assays.

RESULTS

The ERCPG signature was comprised of seven genes (COL4A1, F2R, MMP11, CAV1, VCAN, FKBP10, and APOD). Patients were divided into high- and low-risk groups based on the ERCPG risk scores. Patients in the high-risk group showed a poor prognosis. ROC and calibration curves suggested that the ERCPG signature and nomogram had a good prognostic utility. An immune cell-infiltration analysis suggested that the abnormal expression of ERCPGs induced the formation of an unfavorable tumor immune microenvironment. In vitro cellular assays showed that ERCPGs were more abundantly expressed in GC cell lines compared to normal gastric tissue cell lines.

CONCLUSIONS

We constructed and validated an ERCPG signature using scRNA-seq and bulk sequencing data from ERCs of GC patients. Our findings support the estimation of patient prognosis and tumor treatment in future clinical practice.

Epigenetic Mechanisms of Aging and Aging-Associated Diseases

Aging is an inevitable outcome of life, characterized by a progressive decline in tissue and organ function. At a molecular level, it is marked by the gradual alterations of biomolecules. Indeed, important changes are observed on the DNA, as well as at a protein level, that are influenced by both genetic and environmental parameters. These molecular changes directly contribute to the development or progression of several human pathologies, including cancer, diabetes, osteoporosis, neurodegenerative disorders and others aging-related diseases. Additionally, they increase the risk of mortality. Therefore, deciphering the hallmarks of aging represents a possibility for identifying potential druggable targets to attenuate the aging process, and then the age-related comorbidities. Given the link between aging, genetic, and epigenetic alterations, and given the reversible nature of epigenetic mechanisms, the precisely understanding of these factors may provide a potential therapeutic approach for age-related decline and disease. In this review, we center on epigenetic regulatory mechanisms and their aging-associated changes, highlighting their inferences in age-associated diseases.

Current advances in understanding the molecular profile of hereditary diffuse gastric cancer and its clinical implications

Hereditary diffuse gastric cancer (HDGC) is an autosomal dominant cancer syndrome attributed to germline CDH1 mutations that carries a high risk for early onset DGC. HDGC raises a significant health issue due to its high penetrance and mortality unless diagnosed early. The definitive treatment is to undergo prophylactic total gastrectomy which is associated with significant morbidity., highlighting the urgent need for alternative treatment methods. However, there is limited literature examining potential therapeutic strategies building on emerging insights into the molecular basis of progressive lesions in the context of HDGC. The aim of this review is to summarise the current understanding of HDGC in the context of CDH1 pathogenic variants followed by a review of the proposed mechanisms for progression. In addition, we discuss the development of novel therapeutic approaches and highlight pertinent areas for further research. A literature search was therefore performed for relevant studies examining CDH1 germline variants, second-hit mechanisms of CDH1, pathogenesis of HDGC and potential therapeutic strategies in databases, including PubMed, ScienceDirect and Scopus. Germline mutations are mostly truncating CDH1 variants affecting extracellular domains of E-cadherin, generally due to frameshift, single nucleotide variants or splice site mutations. A second somatic hit of CDH1 most commonly occurs via promoter methylation as shown in 3 studies, but studies are limited with a small sample size. The multi-focal development of indolent lesions in HDGC provide a unique opportunity to understand genetic events that drive the transition to the invasive phenotype. To date, a few signalling pathways have been shown to facilitate the progression of HDGC, including Notch and Wnt. In in-vitro studies, the ability to inhibit Notch signalling was lost in cells transfected with mutant forms of E-cadherin, and increased Notch-1 activity correlated with apoptosis resistance. Furthermore, in patient samples, overexpression of Wnt-2 was associated with cytoplasmic and nuclear β-catenin accumulation and increased metastatic potential. As loss-of-function mutations are challenging to target therapeutically, these findings pave the way towards a synthetic lethal approach in CDH1-deficient cells with some promising results in-vitro. In future, if we could better understand the molecular vulnerabilities in HDGC, there may be opportunities to offer alternative treatment pathways to avoid gastrectomy.

Clinical and prognostic features of E-cadherin in adenocarcinoma of the esophagogastric junction patients

OBJECTIVE

The expression, activity, and functional role of E-cadherin in adenocarcinoma of the esophagogastric junction (AEG) are unclear. In this research, we evaluated the expression of E-cadherin in AEG, as well as its clinicopathological significance and prognostic value.

METHODS

A total of 65 AEG samples and 10 normal paracancerous tissues undergoing AEG resection in thoracic surgery were collected. The samples were immunohistochemically examined for expression levels of E-cadherin. The Chi-square test was used to determine if E-cadherin expression correlated with the clinicopathological features of AEG patients. The link between clinicopathological features and 5-year survival rates was investigated using Kaplan-Meier survival curves and multifactorial Cox regression analysis.

RESULTS

In AEG tissues, E-cadherin expression was considerably reduced. Differentiation grade ( P = 0.013), infiltration depth ( P = 0.033), and clinicopathological stage ( P = 0.045) were substantially linked to the level of E-cadherin expression. Five-year survival rates of AEG patients were affected by E-cadherin expression ( P = 0.037), tumor differentiation ( P = 0.010), lymph node metastasis ( P < 0.001), and clinicopathological stage ( P = 0.037). Tumor differentiation ( P = 0.033) and lymph node metastasis ( P = 0.001) were independent risk factors for shorter overall survival.

CONCLUSION

E-cadherin expression in AEG was significantly decreased, which was strongly related to tumor differentiation, infiltration, and clinicopathological stage. An E-cadherin deficiency would lead to poor prognosis in AEG patients. E-cadherin may play a crucial role in AEG invasion and metastasis. Low expression of E-cadherin may be a potential early biomarker and overall survival predictor for AEG patients.

E-cadherin is a biomarker for ferroptosis sensitivity in diffuse gastric cancer

Gastric cancer is the third most common cause of cancer-related death worldwide. Diffuse-type gastric cancer (DGC) is a particularly aggressive subtype that is both difficult to detect and treat. DGC is distinguished by weak cell-cell cohesion, most often due to loss of the cell adhesion protein E-cadherin, a common occurrence in highly invasive, metastatic cancer cells. In this study, we demonstrate that loss-of-function mutation of E-cadherin in DGC cells results in their increased sensitivity to the non-apoptotic, iron-dependent form of cell death, ferroptosis. Homophilic contacts between E-cadherin molecules on adjacent cells suppress ferroptosis through activation of the Hippo pathway. Furthermore, single nucleotide mutations observed in DGC patients that ablate the homophilic binding capacity of E-cadherin reverse the ability of E-cadherin to suppress ferroptosis in both cell culture and xenograft models. Importantly, although E-cadherin loss in cancer cells is considered an essential event for epithelial-mesenchymal transition and subsequent metastasis, we found that circulating DGC cells lacking E-cadherin expression possess lower metastatic ability, due to their increased susceptibility to ferroptosis. Together, this study suggests that E-cadherin is a biomarker predicting the sensitivity to ferroptosis of DGC cells, both in primary tumor tissue and in circulation, thus guiding the usage of future ferroptosis-inducing therapeutics for the treatment of DGC.

A-Kinase Anchoring Protein 9 Promotes Gastric Cancer Progression as a Downstream Effector of Cadherin 1

Background

Genetic studies identified a dozen of frequently mutated genes in gastric cancer, such as cadherin 1 (CDH1) and A-kinase anchoring protein 9 (AKAP9). Of note, genetic alterations including depletion and amplification frameshift mutations of AKAP9 have been observed in 10–15% of gastric cancer patients. However, it is unknown of the expression and role of AKAP9 in gastric cancer. This study is aimed to characterize the expression and function of AKAP9 in gastric cancer.

Methods

Using qRT-PCR, we analyzed the mRNA levels of AKAP9 in gastric cancer patient samples. We investigated the role of AKAP9 in gastric cancer by performing cell proliferation assay, transwell assay, and mouse xenograft assay.

Results

AKAP9 was upregulated in gastric cancer patients. Overexpression of AKAP9 promoted cell proliferation, migration, and gastric tumor growth. Loss of CDH1 elevated AKAP9 mRNA and protein levels.

Conclusion

Our study demonstrates that AKAP9 functions as an oncoprotein to promote gastric cancer cell proliferation, migration, and tumor growth. Moreover, we reveal a possible molecular link showing that AKAP9 is a critical effector downstream of CDH1 in gastric cancer.

Signaling pathways and therapeutic interventions in gastric cancer

Gastric cancer (GC) ranks fifth in global cancer diagnosis and fourth in cancer-related death. Despite tremendous progress in diagnosis and therapeutic strategies and significant improvements in patient survival, the low malignancy stage is relatively asymptomatic and many GC cases are diagnosed at advanced stages, which leads to unsatisfactory prognosis and high recurrence rates. With the recent advances in genome analysis, biomarkers have been identified that have clinical importance for GC diagnosis, treatment, and prognosis. Modern molecular classifications have uncovered the vital roles that signaling pathways, including EGFR/HER2, p53, PI3K, immune checkpoint pathways, and cell adhesion signaling molecules, play in GC tumorigenesis, progression, metastasis, and therapeutic responsiveness. These biomarkers and molecular classifications open the way for more precise diagnoses and treatments for GC patients. Nevertheless, the relative significance, temporal activation, interaction with GC risk factors, and crosstalk between these signaling pathways in GC are not well understood. Here, we review the regulatory roles of signaling pathways in GC potential biomarkers, and therapeutic targets with an emphasis on recent discoveries. Current therapies, including signaling-based and immunotherapies exploited in the past decade, and the development of treatment for GC, particularly the challenges in developing precision medications, are discussed. These advances provide a direction for the integration of clinical, molecular, and genomic profiles to improve GC diagnosis and treatments.

Capsaicin Inhibits Inflammation and Gastric Damage during H pylori Infection by Targeting NF-kB–miRNA Axis

Helicobacter pylori (H. pylori) infection is considered as one of the strongest risk factors for gastric disorders. Infection triggers several host pathways to elicit inflammation, which further proceeds towards gastric complications. The NF-kB pathway plays a central role in the upregulation of the pro-inflammatory cytokines during infection. It also regulates the transcriptional network of several inflammatory cytokine genes. Hence, targeting NF-kB could be an important strategy to reduce pathogenesis. Moreover, treatment of H. pylori needs attention as current therapeutics lack efficacy due to antibiotic resistance, highlighting the need for alternative therapeutic approaches. In this study, we investigated the effects of capsaicin, a known NF-kB inhibitor in reducing inflammation and gastric complications during H. pylori infection. We observed that capsaicin reduced NF-kB activation and upregulation of cytokine genes in an in vivo mice model. Moreover, it affected NF-kB–miRNA interplay to repress inflammation and gastric damages. Capsaicin reduced the expression level of mir21 and mir223 along with the pro-inflammatory cytokines. The repression of miRNA further affected downstream targets such as e-cadherin and Akt. Our data represent the first evidence that treatment with capsaicin inhibits inflammation and induces antimicrobial activity during H. pylori infection. This alternative approach might open a new avenue in treating H. pylori infection, thus reducing gastric problems.

Helicobacter pylori infection induces stem cell-like properties in Correa cascade of gastric cancer

Gastric cancer (GC) is the fourth leading cause of cancer-related death. Its poor prognosis is attributed to unclear pathogenesis. Currently, the most widely accepted model for elucidating the mechanism of GC is the Correa cascade, which covers several histological lesions of the gastric mucosa. GC stem cells (CSCs) are crucial for oncogenesis in the Correa cascade and GC progression. As Helicobacter pylori (H. pylori) is the etiological factor in the Correa cascade, growing evidence suggests that enhancement of gastric stem cell-like properties and increase in CSCs correlate with H. pylori infection. In this paper, we review recent studies that present pathogenic mechanisms by which H. pylori induces gastric stem cell-like properties and CSCs, which may supplement the existing Correa model of GC. First, the dysfunction of developmental signaling pathways associated with H. pylori infection leads to the enhancement of gastric stemness. Second, H. pylori infection promotes alteration of the gastric mucosal microenvironment. In addition, epithelial-mesenchymal transition (EMT) may contribute to H. pylori-induced gastric stemness. Taken together, understanding these pathogeneses will provide potential therapeutic targets for the treatment of CSCs and malignant GC in H. pylori induced-Correa cascade of GC.

E-Cadherin Signaling in Salivary Gland Development and Autoimmunity

E-cadherin, the major epithelial cadherin, is located in regions of cell–cell contact known as adherens junctions. E-cadherin contributes to the maintenance of the epithelial integrity through homophylic interaction; the cytoplasmic tail of E-cadherin directly binds catenins, forming a dynamic complex that regulates several intracellular signal transduction pathways, including epithelial-to-mesenchymal transition (EMT). Recent progress uncovered a novel and critical role for this adhesion molecule in salivary gland (SG) development and in SG diseases. We summarize the structure and regulation of the E-cadherin gene and transcript in view of the role of this remarkable protein in SG morphogenesis, focusing, in the second part of the review, on altered E-cadherin expression in EMT-mediated SG autoimmunity.

Ferroptosis at the intersection of lipid metabolism and cellular signaling

Ferroptosis, a newly emerged form of regulated necrotic cell death, has been demonstrated to play an important role in multiple diseases including cancer, neurodegeneration, and ischemic organ injury. Mounting evidence also suggests its potential physiological function in tumor suppression and immunity. The execution of ferroptosis is driven by iron-dependent phospholipid peroxidation. As such, the metabolism of biological lipids regulates ferroptosis via controlling phospholipid peroxidation, as well as various other cellular processes relevant to phospholipid peroxidation. In this review, we provide a comprehensive analysis by focusing on how lipid metabolism impacts the initiation, propagation, and termination of phospholipid peroxidation; how multiple signal transduction pathways communicate with ferroptosis via modulating lipid metabolism; and how such intimate cross talk of ferroptosis with lipid metabolism and related signaling pathways can be exploited for the development of rational therapeutic strategies.

HER2-CDH1 Interaction via Wnt/B-Catenin Is Associated with Patients' Survival in HER2-Positive Metastatic Gastric Adenocarcinoma

Trastuzumab is a human epidermal growth factor receptor 2 (HER2) inhibitor used to treat HER2+ metastatic gastric cancer (mGC). The present study aims to investigate the relationship between CDH1 mRNA expression and HER2-positivity in mGC using a multiplexed gene expression profile in two series of gastric cancer (GC): Series 1 (n = 38): HER2+ and HER2- mGC; Series 2 (n = 36) HER2- GC with and without metastasis. To confirm the results, the same expression profiles were analyzed in 354 GC from The Cancer Genome Atlas (TCGA) dataset. The difference in gene expression connected HER2 overexpression with canonical wingless-type (Wnt)/β-catenin pathway and immunohistochemical (IHC) expression loss of E-cadherin (E-CAD). CDH1 mRNA expression was simultaneously associated with the rs16260-A variant and an increase in E-CAD expression. Differences in retinoic acid receptor alfa (RARA), RPL19 (coding for the 60S ribosomal L19 protein), catenin delta 1 (CTNND1), and epidermal growth factor (EGF) mRNA levels-all included in the Wnt/β-catenin pathway-were found associated with overall survival (OS). RARA, CTNND1, and EGF resulted in independent OS prognostic factors. EGF was confirmed as an independent factor along with TNM stage in HER2-overpressed mGC from TCGA collection. Our study highlighted factors involved in the WNT/β-catenin pathway that interconnected E-CAD with HER2 overexpression and patient survival.

Matrix Metalloproteinases in Helicobacter pylori-Associated Gastritis and Gastric Cancer

Gastric cancer is one of the leading causes of the cancer-related mortality worldwide. The etiology of this disease is complex and involves genetic predisposition and environmental factors, including Helicobacter pylori. Infection of the stomach with H. pylori leads to gastritis and gastric atrophy, which can progress stepwise to gastric cancer. Matrix metalloproteinases (MMPs) actively participate in the pathology development. The further progression of gastric cancer seems to be less dependent on bacteria but of intra-tumor cell dynamics. Bioinformatics data confirmed an important role of the extracellular matrix constituents and specific MMPs in stomach carcinoma invasion and metastasis, and revised their potential as predictors of the disease outcome. In this review, we describe, in detail, the impact of MMPs in H. pylori-associated gastritis and gastric cancer.

E-Cadherin-Deficient Epithelial Cells Are Sensitive to HDAC Inhibitors

Inactivating germline mutations in the CDH1 gene (encoding the E-cadherin protein) are the genetic hallmark of hereditary diffuse gastric cancer (HDGC), and somatic CDH1 mutations are an early event in the development of sporadic diffuse gastric cancer (DGC) and lobular breast cancer (LBC). In this study, histone deacetylase (HDAC) inhibitors were tested for their ability to preferentially inhibit the growth of human cell lines (MCF10A and NCI-N87) and murine organoids lacking CDH1 expression. CDH1^-/- breast and gastric cells were more sensitive to the pan-HDAC inhibitors entinostat, pracinostat, mocetinostat and vorinostat than wild-type cells, with an elevated growth inhibition that was, in part, attributable to increased apoptosis. CDH1-null cells were also sensitive to more class-specific HDAC inhibitors, but compared to the pan-inhibitors, these effects were less robust to genetic background. Increased sensitivity to entinostat was also observed in gastric organoids with both Cdh1 and Tp53 deletions. However, the deletion of Tp53 largely abrogated the sensitivity of the Cdh1-null organoids to pracinostat and mocetinostat. Finally, entinostat enhanced Cdh1 expression in heterozygous Cdh1^+/- murine organoids. In conclusion, entinostat is a promising drug for the chemoprevention and/or treatment of HDGC and may also be beneficial for the treatment of sporadic CDH1-deficient cancers.

Cadherin Signaling in Cancer and Autoimmune Diseases

Cadherins mediate cell–cell adhesion through a dynamic process that is strongly dependent on the cellular context and signaling. Cadherin regulation reflects the interplay between fundamental cellular processes, including morphogenesis, proliferation, programmed cell death, surface organization of receptors, cytoskeletal organization, and cell trafficking. The variety of molecular mechanisms and cellular functions regulated by cadherins suggests that we have only scratched the surface in terms of clarifying the functions mediated by these versatile proteins. Altered cadherins expression is closely connected with tumorigenesis, epithelial–mesenchymal transition (EMT)-dependent fibrosis, and autoimmunity. We review the current understanding of how cadherins contribute to human health and disease, considering the mechanisms of cadherin involvement in diseases progression, as well as the clinical significance of cadherins as therapeutic targets.

Bioinformatics Analysis of Hub Genes and Potential Therapeutic Agents Associated with Gastric Cancer

Purpose

The current treatment methods available for advanced gastric cancer are not very promising. Hence, it is important to explore novel biomarkers and potential therapeutic agents to treat gastric cancer (GC). This study aimed to identify hub genes associated with GC prognosis and explore potential drugs for its treatment.

Materials and Methods

Three gene expression data of GC and normal tissues were downloaded from the Gene Expression Omnibus (GEO) and processed to identify the differentially expressed genes (DEGs). We conducted a comprehensive analysis of DEGs, including functional enrichment analysis, construction of protein-protein interaction (PPI) network, identification of hub genes, survival analysis and expression verification of hub genes. Finally, we constructed the network of miRNA-mRNA, and predicted the drugs that might be effective for GC treatment.

Results

A total of 340 DEGs, including 94 up-regulated and 246 down-regulated genes, were identified. Among the up-regulated DEGs, the enrichment terms were primarily related to tumorigenesis and tumor progression, extracellular matrix organization, and collagen catabolic process. Additionally, 10 hub genes (FN1, COL3A1, COL1A2, BGN, THBS2, COL5A2, THBS1, COL5A1, SPARC, and COL4A1) were identified, out of which 7 genes were significantly associated with poor overall survival (OS) in GC. The expression levels of these 7 hub genes were verified using real-time PCR, immunohistochemistry, and the GEPIA2 (Gene Expression Profiling Interactive Analysis) server. A regulatory network of miRNA-mRNA was also constructed, and the top 4 interactive miRNAs (hsa-miR-29b-3p, hsa-miR-140-3p, hsa-miR-29a-3p, and hsa-miR-29c-3p) that targeted the most hub genes were identified. Finally, fourteen small molecules were predicted to be effective in treating GC.

Conclusion

The identification of the hub genes, miRNA-mRNA network, and potential candidate drugs associated with GC provides new insights into the molecular mechanisms and treatment of GC.

Crosstalk between E-Cadherin/β-Catenin and NF-κB Signaling Pathways: The Regulation of Host-Pathogen Interaction during Leptospirosis

Approximately 1 million cases of leptospirosis, an emerging infectious zoonotic disease, are reported each year. Pathogenic Leptospira species express leucine-rich repeat (LRR) proteins that are rarely expressed in non-pathogenic Leptospira species. The LRR domain-containing protein family is vital for the virulence of pathogenic Leptospira species. In this study, the biological mechanisms of an essential LRR domain protein from pathogenic Leptospira were examined. The effects of Leptospira and recombinant LRR20 (rLRR20) on the expression levels of factors involved in signal transduction were examined using microarray, quantitative real-time polymerase chain reaction, and western blotting. The secreted biomarkers were measured using an enzyme-linked immunosorbent assay. rLRR20 colocalized with E-cadherin on the cell surface and activated the downstream transcription factor β-catenin, which subsequently promoted the expression of MMP7, a kidney injury biomarker. Additionally, MMP7 inhibitors were used to demonstrate that the secreted MMP7 degrades surface E-cadherin. This feedback inhibition mechanism downregulated surface E-cadherin expression and inhibited the colonization of Leptospira. The degradation of surface E-cadherin activated the NF-κB signal transduction pathway. Leptospirosis-associated acute kidney injury is associated with the secretion of NGAL, a downstream upregulated biomarker of the NF-κB signal transduction pathway. A working model was proposed to illustrate the crosstalk between E-cadherin/β-catenin and NF-κB signal transduction pathways during Leptospira infection. Thus, rLRR20 of Leptospira induces kidney injury in host cells and inhibits the adhesion and invasion of Leptospira through the upregulation of MMP7 and NGAL.

Aberrant expression of SFRP1, SFRP3, DVL2 and DVL3 Wnt signaling pathway components in diffuse gastric carcinoma

Diffuse gastric carcinoma (DGC) is characterized by poorly cohesive cells, highly invasive growth patterns, poor prognosis and resistance to the majority of available systemic therapeutic strategies. It has been previously reported that the Wnt/β-catenin signaling pathway serves a prominent role in the tumorigenesis of gastric carcinoma. However, the mechanism underlying the dysregulation of this pathway in DGC has not been fully elucidated. Therefore, the present study aimed to investigate the expression profiles of Wnt antagonists, secreted frizzled-related protein 1 (SFRP1) and secreted frizzled-related protein 3 (SFRP3), and dishevelled protein family members, dishevelled segment polarity protein 2 (DVL2) and dishevelled segment polarity protein 3 (DVL3), in DGC tissues. The association between the expression levels of these factors and the clinicopathological parameters of the patients was determined. Protein and mRNA expression levels in 62 DGC tumor tissues and 62 normal gastric mucosal tissues obtained from patients with non-malignant disease were measured using immunohistochemical and reverse transcription-quantitative PCR (RT-qPCR) analysis. Significantly lower protein expression levels of SFRP1 (P<0.001) and SFRP3 (P<0.001), but significantly higher protein expression levels of DVL2 (P<0.001) and DVL3 (P<0.001) were observed in DGC tissues compared with in control tissues by immunohistochemistry. In addition, significantly lower expression levels of SFRP1 (P<0.05) and higher expression levels of DVL3 (P<0.05) were found in in DGC tissues compared with those in normal gastric mucosal tissues using RT-qPCR. According to correlation analysis between the SFRP1, SFRP3, DVL2 and DVL3 protein expression levels and the clinicopathological characteristics of patients with DGC, a statistically significant correlation was found between the SFRP3 volume density and T stage (r=0.304; P=0.017) and between the SFRP3 volume density and clinical stage (r=0.336; P=0.008). In conclusion, the findings of the present study suggested that the Wnt signaling pathway components SFRP1, SFRP3, DVL2 and DVL3 may be aberrantly expressed in DGC tissues, implicating their possible role in the development of this malignant disease. The present data also revealed a positive relationship between SFRP3 protein expression and the clinical and T stage of DGC.

MicroRNA-140-3p represses the proliferation, migration, invasion and angiogenesis of lung adenocarcinoma cells via targeting TYMS (thymidylate synthetase)

MicroRNA (miR)-140-3p has been proved to repress lung adenocarcinoma (LUAD), and our study aims to further evaluate the mechanism. Bioinformatic analyses were performed. The viability, proliferation, migration, invasion and angiogenesis of transfected LUAD cells were all determined via Cell Counting Kit-8, colony formation, Scratch, Transwell, and tube formation assays. The targeting relationship between miR-140-3p and thymidylate synthetase (TYMS) was confirmed by dual-luciferase reporter assay. Relative expressions of miR-140-3p, TYMS, epithelial-to-mesenchymal transition- (E-cadherin, N-cadherin, vimentin), angiogenesis- (vascular endothelial growth factor (VEGF)), and apoptosis-related factors (cleaved caspase-3, B-cell lymphoma-2 (Bcl-2), Bcl-2-associated X protein (Bax)) were quantified by quantitative real-time polymerase chain reaction or Western blot. TYMS was high-expressed yet miR-140-3p was low-expressed in LUAD cells. Upregulation of miR-140-3p inhibited TYMS expression, viability, colony formation, migration, invasion, and tube length within LUAD cells, while downregulation of miR-140-3p did oppositely. Silenced TYMS, the downstream target gene of miR-140-3p, reversed the effects of miR-140-3p downregulation on TYMS expression, cell viability, colony formation, migration, invasion, and tube length as well as the metastasis-, apoptosis- and angiogenesis-related proteins in LUAD cells. Upregulation of miR-140-3p inhibited the proliferation, migration, invasion and angiogenesis of LUAD cells via targeting TYMS.

TGF-β-MTA1-SMAD7-SMAD3-SOX4-EZH2 Signaling Axis Promotes Viability, Migration, Invasion and EMT of Hepatocellular Carcinoma Cells

Introduction

Enhancer of zeste homolog 2 (EZH2) is implicated in hepatocellular carcinoma (HCC), but whether transforming growth factor-β (TGF-β)-metastasis associated 1 (MTA1)-SMAD7-SMAD3-SRY-Box Transcription Factor 4 (SOX4)-EZH2 signaling axis, in which EZH2 participates, is also involved in HCC remained unknown.

Methods

Data on EZH2 expression in liver hepatocellular carcinoma (LIHC) and its relation with prognosis of HCC patients were predicted and analyzed using online databases. Following transfection with or without TGF-β1, HCC cell viability, migration and invasion were determined with MTT, Scratch and Transwell assays. Relative expressions of epithelial-to-mesenchymal transition (EMT)-related factors (N-Cadherin, Vimentin, and E-Cadherin) and TGF-β-MTA1-SMAD7-SMAD3-SOX4-EZH2 signaling axis factors (TGF-β, MTA1, SMAD7, phosphorylated-SMAD3, SOX4 and EZH2) were calculated via reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and Western blot.

Results

EZH2 was upregulated in HCC, which was related to poor prognosis. Silencing EZH2 suppressed EZH2 expression and HCC cell viability, migration, and invasion, and increased E-Cadherin expression yet decreased N-Cadherin and Vimentin expression, whereas EZH2 overexpression did conversely. Also, silencing EZH2 reversed the effects of TGF-β1 on promoting viability, migration, and invasion, as well as N-Cadherin and Vimentin expressions, yet suppressing E-Cadherin expression in HCC cells. In addition, TGF-β1 promoted TGF-β, MTA1, SOX4 and EZH2 expressions and p-SMAD3/SMAD3 ratio yet suppressed SMAD7, whereas silencing EZH2 solely reversed the effects of TGF-β1 on EZH2 expression in HCC cells.

Conclusion

The present study provides a theoretical basis for TGF-β-MTA1-SMAD7-SMAD3-SOX4-EZH2 signaling cascade in viability, migration, invasion, and EMT of HCC cells. Inhibiting these signals may represent a therapeutic pathway for the treatment of metastatic HCC.

Long non-coding RNA PCED1B antisense RNA 1 promotes gastric cancer progression via modulating microRNA-215-3p / C-X-C motif chemokine receptor 1 axis

Long non-coding RNAs (lncRNAs) emerge as vital modulators and tissue-specific biomarkers of multiple cancers, including gastric cancer (GC). Instead, the expression characteristics, biological function and molecular mechanism of lncRNA PCED1B antisense RNA 1 (PCED1B-AS1) in GC await more elaboration. In this study, 48 cases of GC tissues and matched non-cancerous tissues were collected, and PCED1B-AS1, microRNA-215-3p (miR-215-3p) and C-X-C motif chemokine receptor 1 (CXCR1) expression levels were detected by qRT-PCR. Besides, CCK-8, EdU, Transwell and Western blot assays were conducted to assess the impact of PCED1B-AS1 or miR-215-3p on cell growth, migration, invasion and epithelial-mesenchymal transition (EMT). The interaction between genes was verified by bioinformatics analysis, rna immunoprecitipation (RIP) and dual-luciferase reporter gene assays. We demonstrated that, PCED1B-AS1 expression level was raised in GC tissues and cell lines, and increased expression of PCED1B-AS1 was in association with tumor size, TNM stage and lymph node metastasis in GC patients. Additionally, PCED1B-AS1 overexpression promoted GC cells proliferation, migration, invasion and EMT, and miR-215-3p overexpression counteracted the biological effects of PCED1B-AS1. Mechanistically, PCED1B-AS1 specifically inhibited miR-215-3p expressions, thus up-regulating CXCR1 expressions. In conclusion, PCED1B-AS1 accelerates GC progression via adsorbing miR-215-3p and up-regulating CXCR1, indicating that PCED1B-AS1 is a novel therapeutic target for treating GC.

Helicobacter pylori in Human Stomach: The Inconsistencies in Clinical Outcomes and the Probable Causes

Pathogenic potentials of the gastric pathogen, Helicobacter pylori, have been proposed, evaluated, and confirmed by many laboratories for nearly 4 decades since its serendipitous discovery in 1983 by Barry James Marshall and John Robin Warren. Helicobacter pylori is the first bacterium to be categorized as a definite carcinogen by the International Agency for Research on Cancer (IARC) of the World Health Organization (WHO). Half of the world’s population carries H. pylori, which may be responsible for severe gastric diseases like peptic ulcer and gastric cancer. These two gastric diseases take more than a million lives every year. However, the role of H. pylori as sole pathogen in gastric diseases is heavily debated and remained controversial. It is still not convincingly understood, why most (80–90%) H. pylori infected individuals remain asymptomatic, while some (10–20%) develop such severe gastric diseases. Moreover, several reports indicated that colonization of H. pylori has positive and negative associations with several other gastrointestinal (GI) and non-GI diseases. In this review, we have discussed the state of the art knowledge on “H. pylori factors” and several “other factors,” which have been claimed to have links with severe gastric and duodenal diseases. We conclude that H. pylori infection alone does not satisfy the “necessary and sufficient” condition for developing aggressive clinical outcomes. Rather, the cumulative effect of a number of factors like the virulence proteins of H. pylori, local geography and climate, genetic background and immunity of the host, gastric and intestinal microbiota, and dietary habit and history of medicine usage together determine whether the H. pylori infected person will remain asymptomatic or will develop one of the severe gastric diseases.

PARP1 Is Targeted by miR-519a-3p and Promotes the Migration, Invasion, and Tube Formation of Ovarian Cancer Cells

Background: Poly ADP-ribose polymerase 1 (PARP1) has been discovered to be implicated in ovarian cancer (OC), but its interaction with microRNA (miR)-519a-3p remained poorly understood. This study aimed to uncover their roles and interactions in OC. Materials and Methods: Clinical tissue from OC patients and adjacent normal tissue were collected, and the survival rates of OC patients with high or low PARP1 expression were analyzed by Kaplan-Meier curve. After transfection, OC cell viability, migration, and tube formation were detected with cell counting kit-8 (CCK-8) assay, scratch assay, and tube formation assay, respectively. Target gene of miR-519a-3p and potential binding sites between them were predicted with TargetScan and confirmed using dual-luciferase reporter assay. Relative expressions of miR-519a-3p, PARP1, E-cadherin, N-cadherin, SNAIL, vascular endothelial growth factor (VEGF), and p53 were measured by quantitative real-time polymerase chain reaction and Western blot as needed. Results: PARP1 expression was upregulated in OC, which was related to poor prognosis of OC patients. Silencing PARP1 decreased PARP1 expression and suppressed viability, migration, invasion, and tube formation in OC cells, while overexpressed PARP1 did the opposite. PARP1 was the target gene of miR-519a-3p, and it reversed the effects of miR-519a-3p on the migration, invasion, and tube formation of OC cells by upregulating the expressions of PAR, PARP1, N-cadherin, SNAIL, and VEGF and downregulating those of E-cadherin and p53. Conclusion: PARP1, a target gene of miR-519a-3p, promoted the migration, invasion, and tube formation of OC cells, providing a possible therapeutic target for treatment of OC patients.

Clinicopathological profile and its association with peritoneal disease among gastric cancer patients

BACKGROUND

There are no clinicopathological criteria or test to predict peritoneal metastasis either in primary or recurrent gastric cancer. The early prediction will help in altering or adding other adjuvant potential therapy modalities like HIPEC and maintenance chemotherapy.

METHODS

Paraffin based blocks of 110 gastric tumor specimens were subjected to IHC staining to assess VEGF, Her 2 neu, E cadherin, bcl 2 and p 53 expression and its association with peritoneal disease evaluated.

RESULTS

Her 2 neu uptake was present in 17.3%, bcl-2 expression in 19.1%, P53 expression in 40.9%, VEGF in 41.8% and E cadherin expression in 49.1% patients. On univariate analysis, a younger age(p = .029), female sex(p = .026), positive VEGF expression (p = .001) and p53 expression(p = .015) were significantly associated with peritoneal disease. A binomial logistic regression was performed to ascertain the effects of independent variables evaluated on univariate analysis. Of the 10 predictors variables, only three were statistically significant: tumor type, P53, and VEGF. Positive VEGF expression had 48.7, E cadherin 2.6 and Her2neu 1.5 times higher odds of exhibiting peritoneal disease.

CONCLUSION

A younger age, female sex, distal 2/3rd, diffuse variant, VEGF staining in >10% cells and decrease p53 expression were associated with peritoneal disease.

MiR-205 Promotes the Viability, Migration, and Tube Formation of Cervical Cancer Cells In Vitro by Targeting GATA3

Background: Both microRNA (miR)-205 and GATA Binding Protein 3 (GATA3) were involved in cervical cancer (CC), yet their correlation remained poorly understood. The authors' study aimed to unveil their correlation in CC. Materials and Methods: Clinical cervical tissue samples were collected. Survival rates of CC patients with high or low miR-205 and GATA3 expressions were analyzed using Kaplan-Meier curve. CC cell viability, migration, and tube formation were measured by cell counting kit-8 assay, scratch assay, and tube formation assay, respectively. The potential binding sites between miR-205 and GATA3 were predicted by TargetScan, and confirmed with dual-luciferase reporter assay. Relative expressions of miR-205, GATA3, vascular endothelial growth factor, E-cadherin, N-cadherin, and vimentin were quantified with quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot as needed. Results: MiR-205 was increased, yet GATA3 was decreased in CC, indicating that they were negatively correlated. Upregulating miR-205 increased miR-205 expression and CC cell viability and promoted migration and tube formation, yet decreased GATA3 expression, while downregulating miR-205 exerted the opposite effects. GATA3 was the target gene of miR-205, and reversed the effect of miR-205 on GATA3 expression and cell viability, migration, and tube formation in CC cells by reversing the effects of miR-205 on migration- and tube formation-related protein expressions. Conclusion: MiR-205 promotes CC cell viability, migration, and tube formation in vitro by targeting GATA3, providing new evidence for the implication of miR-205 in CC and a possible therapeutic method for CC. Clinical Trial Registration number: ZLK-20181103-01.

Clinical Significance of CLDN18.2 Expression in Metastatic Diffuse-Type Gastric Cancer

Purpose

Isoform 2 of tight junction protein claudin-18 (CLDN18.2) is a potential target for gastric cancer treatment. A treatment targeting CLDN18.2 has shown promising results in gastric cancer. We investigated the clinical significance of CLDN18.2 and other cell-adherens junction molecules (Rho GTPase-activating protein [RhoGAP] and E-cadherin) in metastatic diffuse-type gastric cancer (mDGC).

Materials and Methods

We evaluated CLDN18.2, RhoGAP, and E-cadherin expression using two-plex immunofluorescence and quantitative data analysis of H-scores of 77 consecutive mDGC patients who received first-line platinum-based chemotherapy between March 2015 and February 2017.

Results

CLDN18.2 and E-cadherin expression was significantly lower in patients with peritoneal metastasis (PM) than those without PM at the time of diagnosis (P=0.010 and 0.013, respectively), whereas it was significantly higher in patients who never developed PM from diagnosis to death than in those who did (P=0.001 and 0.003, respectively). Meanwhile, CLDN18.2 and E-cadherin expression levels were significantly higher in patients with bone metastasis than in those without bone metastasis (P=0.010 and 0.001, respectively). Moreover, we identified a positive correlation between the expression of CLDN18.2 and E-cadherin (P<0.001), RhoGAP and CLDN18.2 (P=0.004), and RhoGAP and E-cadherin (P=0.001). Conversely, CLDN18.2, RhoGAP, and E-cadherin expression was not associated with chemotherapy response and survival.

Conclusions

CLDN18.2 expression was reduced in patients with PM but significantly intact in those with bone metastasis. Furthermore, CLDN18.2 expression was positively correlated with other adherens junction molecules, which is clinically associated with mDGC and PM pathogenesis.

Dexamethasone Reduces Cell Adhesion and Migration of T47D Breast Cancer Cell Line

BACKGROUND

Aberrant expression of cell adhesion molecules and matrix metalloproteinase (MMPs) plays a pivotal role in tumor biological processes including progression and metastasis of cancer cells. Targeting these processes and detailed understanding of their underlying molecular mechanism is an essential step in cancer treatment. Dexamethasone (Dex) is a type of synthetic corticosteroid hormone used as adjuvant therapy in combination with current cancer treatments such as chemotherapy in order to alleviate its side effects like acute nausea and vomiting. Recent evidences have suggested that Dex may have antitumor characteristics.

OBJECTIVE

Dex affects the migration and adhesion of T47D breast cancer cells as well as cell adhesion molecules e.g., cadherin and integrin, and MMPs by regulating the expression levels of associated genes.

METHODS

In this study, we evaluated the cytotoxicity of Dex on the T47D breast cancer cell line through MTT assay. Cell adhesion assay and wound healing assay were performed to determine the impact of Dex on cell adhesion and cell migration, respectively. Moreover, real-time PCR was used to measure the levels of α and β integrin, E-cadherin, N-cadherin, MMP-2, and MMP-9.

RESULTS

Dex decreased the viability of T47D cells in a time and dose-dependent manner. Cell adhesion and migration of T47D cells were reduced upon Dex treatment. The expression of α and β integrin, E-cadherin, N-cadherin, MMP-2, and MMP-9 were altered in response to the Dex treatment.

CONCLUSION

Our findings demonstrated that Dex may have a role in the prevention of metastasis in this cell line.

Molecular Alterations in Metastatic Ovarian Cancer From Gastrointestinal Cancer

Reports indicate that most metastatic ovarian cancer (MOC) originates from gastrointestinal cancer (GIC). Notably, GICs metastasize to the ovary frequently via 3 main routes including hematogenous spread, lymphogenous spread, and transcoelomic spread. Nonetheless, the mechanism of the progression remains unknown, and only a handful of literature exists on the molecular alteration implicated in MOC from GIC. This work collected existing evidence and literature on the vital molecules of the metastatic pathway and systematically analyzed them geared toward exploring the mechanism of the metastatic pathway of MOC. Further, this review described dominating molecular alteration in the metastatic process from cancer cells detaching away from lesions to arrive at the ovary, including factors for regulating signaling pathways in epithelial-interstitial transformation, invading, and surviving in the circulatory system or abdominal cavity. We interrogated the basis of the ovary as a distant metastatic site. This article provides new insights into the metastatic pathway and generates novel therapeutic targets for effective treatment and satisfactory outcomes in GIC patients.

Reactive Oxygen Species-Mediated Mitochondrial Dysfunction Triggers Sodium Valproate-Induced Cytotoxicity in Human Colorectal Adenocarcinoma Cells

BACKGROUND

Colorectal cancer (CRC) is one of the frequently diagnosed cancers worldwide. Currently used chemotherapeutic drugs have several side effects. Histone deacetylase (HDAC) enzyme inhibitors possess potential anti-cancer effects. Therefore, we investigated the cytotoxic potential of sodium valproate, a HDAC inhibitor in human colorectal adenocarcinoma (HT-29) cells.

METHODS

MTT assay was used to analyze the cytotoxicity of HT-29 cells. Intracellular reactive oxygen species (ROS) induction was evaluated by dichloro-dihydro-fluorescein diacetate staining. Dual staining with acridine orange/ethidium bromide was used to investigate the morphology-related apoptotic cell death. Mitochondrial membrane potential was analyzed by rhodamine 123 staining. E-cadherin protein expression was examined by immunofluorescence staining.

RESULTS

Sodium valproate at 2 and 4 mM/mL treatments significantly induced cytotoxicity. Increased intracellular ROS expression was observed in the cells treated with sodium valproate. This treatment also induced mitochondrial dissipation, apoptosis-related morphological damage, and E-cadherin expression in HT-29 cells.

CONCLUSIONS

Our present results suggest that sodium valproate is cytotoxic to HT-29 cells due to its pro-oxidative and apoptosis inducing potential. Sodium valproate can be used as an adjuvant along with standard chemotherapeutic agents in CRC patients after necessary in vivo and clinical studies.

Molecular mediators of peritoneal metastasis in pancreatic cancer

Pancreatic cancer is the third leading cause of cancer death in the USA, and pancreatic ductal adenocarcinoma (PDA) constitutes 85% of pancreatic cancer diagnoses. PDA frequently metastasizes to the peritoneum, but effective treatment of peritoneal metastasis remains a clinical challenge. Despite this unmet need, understanding of the biological mechanisms that contribute to development and progression of PDA peritoneal metastasis is sparse. By contrast, a vast number of studies have investigated mechanisms of peritoneal metastasis in ovarian and gastric cancers. Here, we contrast similarities and differences between peritoneal metastasis in PDA as compared with those in gastric and ovarian cancer by outlining molecular mediators involved in each step of the peritoneal metastasis cascade. This review aims to provide mechanistic insights that could be translated into effective targeted therapies for patients with peritoneal metastasis from PDA.

Epigenetic Mechanisms in Gastric Cancer: Potential New Therapeutic Opportunities

Gastric cancer (GC) is one of the deadliest malignancies worldwide. Complex disease heterogeneity, late diagnosis, and suboptimal therapies result in the poor prognosis of patients. Besides genetic alterations and environmental factors, it has been demonstrated that alterations of the epigenetic machinery guide cancer onset and progression, representing a hallmark of gastric malignancies. Moreover, epigenetic mechanisms undergo an intricate crosstalk, and distinct epigenomic profiles can be shaped under different microenvironmental contexts. In this scenario, targeting epigenetic mechanisms could be an interesting therapeutic strategy to overcome gastric cancer heterogeneity, and the efforts conducted to date are delivering promising results. In this review, we summarize the key epigenetic events involved in gastric cancer development. We conclude with a discussion of new promising epigenetic strategies for gastric cancer treatment.

Clinical and genomic characteristics of mucosal signet-ring cell carcinoma in Helicobacter pylori-uninfected stomach

BACKGROUND

Gastric cancer develops even in Helicobacter pylori(H. pylori)-uninfected patients and its typical histological feature is signet ring cell carcinoma (SRCC) within the mucosal layer. However, the biological characteristics of SRCC remain unclear. We aimed to clarify the pathological and genetic features of SRCC in H. pylori-uninfected patients.

METHODS

Seventeen H. pylori-uninfected patients with mucosal SRCCs were enrolled and their clinicopathological characteristics were compared with those of H. pylori-infected patients with mucosal SRCCs. Seven SRCCs without H. pylori-infected, including two invasive SRCCs, and seven H. pylori-infected SRCCs were subjected to a genetic analysis using next-generation sequencing.

RESULTS

H. pylori-uninfected patients with mucosal SRCCs revealed male dominancy and a significantly higher prevalence of smokers among them as compared with the H. pylori-infected patients with SRCC. A CDH1 mutation (frame shift indel) was detected in one H. pylori-uninfected cancer not only in the mucosal SRCC but also in the invasive portion. A TP53 mutation was detected in one SRCC without H. pylori-infected. In the control group, ARID1A and TP53 mutations were detected in one SRCC each. The C to A mutation, which is a characteristic smoking-induced mutation, was not found in any of the samples.

CONCLUSIONS

Some SRCCs in H. pylori-uninfected patients may have a malignant potential similar to that of SRCCs in H. pylori-infected patients. Smoking may not be the main carcinogenic factor for the development of SRCCs among the H. pylori-uninfected patients.

Overexpression of negative regulator of ubiquitin-like proteins 1 (NUB1) inhibits proliferation and invasion of gastric cancer cells through upregulation of p27Kip1 and inhibition of epithelial-mesenchymal transition

BACKGROUND

Gastric cancer (GC), one of the most common causes of malignant tumors, is characterized by a high degree of heterogeneity, which represents a bottleneck in gaining comprehensive insights into its pathogenesis. Negative regulator of ubiquitin-like proteins 1 (NUB1) is a transcription factor that negatively regulates ubiquitylation system. Although the abnormal expression of NUB1 has been reported in many types of cancer, its expression pattern and functions in GC are poorly understood.

MATERIALS AND METHODS

The link between NUB1 expression and clinicopathological characteristics was analyzed by immunohistochemical staining, and the suitability of NUB1 as a prognostic marker was explored using a public database on mRNA expression levels. NUB1 overexpression was performed by lentiviral transfection. Cell proliferation was estimated using the cell counting kit-8 (CCK-8) assay. The effect on NUB1 on cell cycle was analyzed by fluorescence-activated cell sorting (FACS). Real-time PCR (RT-PCR) and western blotting experiments were used to explore the mechanism of p27Kip1 regulation by NUB1. Cell migration and invasion were determined by wound healing and transwell assays, respectively. Expression levels of epithelial-mesenchymal transition (EMT) indicator proteins were determined by western blotting.

RESULTS

In this study, based on a comparative analysis of cancer tissues from 116 post-operative GC patients with the respective paracancerous healthy tissues, we found that NUB1 was downregulated in GC tissues. At the same time, a low expression level of NUB1 was closely related to poor prognosis. Results from In vitro cancer cell experiments verified that overexpressed NUB1 inhibited GC proliferation, migration, and invasion. In addition, NUB1 upregulated the expression of p27Kip1 and blocked the G1/S phase transition in cell cycle. Finally, NUB1 inhibited the process of EMT by upregulating E-cadherin and downregulating N-cadherin, vimentin, and matrix metalloproteinase-2 (MMP-2).

CONCLUSION

Reduced NUB1 levels were positively associated to poor prognosis of GC, whereas NUB1 overexpression inhibited the proliferation and blocked the G1/S phase transition in GC cells. This may be strongly coupled to the post-translational modification mechanism (PTM), which could, in turn, reduce the level of ubiquitinylated p27Kip1 and upregulate its expression. In addition, NUB1 overexpression inhibited GC migration and invasion by regulating EMT. In view of the positive tumor-suppressive effect of NUB1 on GC occurrence and progression reported here, this study enhances our understanding of the molecular mechanism of NUB1-mediated GC regulation, and may provide insights into novel drug targets or anti-tumor strategies with better accuracy and efficacy.

Ribosomal DNA copy number is associated with P53 status and levels of heavy metals in gastrectomy specimens from gastric cancer patients

The ribosomal DNA (rDNA) can act as a sensor and responder of cancer-associated stress. Here we investigated rDNA copy number in gastric cancers and its association with existing biomarkers and metals exposure. This study was performed on paired tumor and adjacent normal tissues obtained from 65 gastric cancer patients who underwent gastrectomy. Immunohistochemistry was used to assess HER-2, E-cadherin, EGFR, CK (pan), CK20, CK7, TopoⅡ, CAM5.2, P53, and Ki-67 expression. Inductively coupled plasma mass spectrometry (ICP-MS) was used to detect the concentrations of 17 metals in gastric tissues. rDNA copy number was detected by qPCR in genomic DNA isolated from tissue samples. Associations between the expression of existing markers, metal concentrations, and rDNA copy number were evaluated. Within patients with gastric cancer, the copy number of the 45S rDNA components (18S, 5.8S, 28S) and the 5S rDNA in tumor tissues were significantly higher than those in adjacent normal tissues, whereas mitochondrial DNA (mtDNA) copy number was significantly lower in tumor tissues than that in adjacent normal tissues. Further analysis revealed that the increase in 18S, 5.8S, and 28S rDNA copy number in tumor tissues was diminished in the context of EGFR and P53 loss. Moreover, analysis of metals revealed particularly high concentrations of As, Cd, Cr, Cu and Fe in the gastric tissues of these patients. Intriguingly, rDNA copy number variation across individuals was correlated with the concentrations of some metals. The rDNA was amplified in tumor tissues of gastric cancer patients, and its amplification may be associated with metals exposure. The expression of EGFR and P53 may influence rDNA copy number, with diminished amplification of the rDNA in cancers that were negative for these biomarkers. Our observation further our understanding of rDNA copy number in gastric cancer and its potential as a simple and useful marker in gastric cancer monitoring.

Gastric Cancer in Young Adults: A Different Clinical Entity from Carcinogenesis to Prognosis

Approximately 5.0% of gastric cancer (GC) patients are diagnosed before the age of 40 and are not candidates for screening programs in most countries and regions. The incidence of gastric cancer in young adults (GCYA) has declined over time in most countries except in the United States. Genetic alterations, environmental factors, and lifestyle may predispose some young adults to GC. According to molecular classifications, the cancer of most GCYA patients belongs to the genomically stable or microsatellite stable/epithelial-mesenchymal transition subtype, with the common genetic aberrations being mutations in CDH1. What characterizes GCYA are a higher prevalence in females, more aggressive tumor behaviors, diagnosis at advanced stages, fewer comorbidities and being better treatment candidates, and a similar or better survival outcome when compared with older patients. Considering the greater loss of life-years in younger patients, lowering the incidence of GC and diagnosing at a relatively early stage are the two most effective ways to decrease GC mortality. To achieve these goals, the low awareness of GCYA among general people, policy-makers, clinicians, and researchers should be changed.

Identification of potential key genes in gastric cancer using bioinformatics analysis

Gastric cancer (GC) is one of the most common types of cancer worldwide. Patients must be identified at an early stage of tumor progression for treatment to be effective. The aim of the present study was to identify potential biomarkers with diagnostic value in patients with GC. To examine potential therapeutic targets for GC, four Gene Expression Omnibus (GEO) datasets were downloaded and screened for differentially expressed genes (DEGs). Gene Ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were subsequently performed to study the function and pathway enrichment of the identified DEGs. A protein-protein interaction (PPI) network was constructed. The CytoHubba plugin of Cytoscape was used to calculate the degree of connectivity of proteins in the PPI network, and the two genes with the highest degree of connectivity were selected for further analysis. Additionally, the two DEGs with the largest and smallest log Fold Change values were selected. These six key genes were further examined using Oncomine and the Kaplan-Meier plotter platform. A total of 99 upregulated and 172 downregulated genes common to all four GEO datasets were screened. The DEGs were primarily enriched in the Biological Process terms: ‘extracellular matrix organization’, ‘collagen catabolic process’ and ‘cell adhesion’. These three KEGG pathways were significantly enriched in the categories: ‘ECM-receptor interaction’, ‘protein digestion and absorption’, and ‘focal adhesion’. Based on Oncomine, expression of ATP4A and ATP4B were downregulated in GC, whereas expression of the other genes were all upregulated. The Kaplan-Meier plotter platform confirmed that upregulated expression of the identified key genes was significantly associated with worse overall survival of patients with GC. The results of the present study suggest that FN1, COL1A1, INHBA and CST1 may be potential biomarkers and therapeutic targets for GC. Additional studies are required to explore the potential value of ATP4A and ATP4B in the treatment of GC.

Novel Variants and Copy Number Variation in CDH1 Gene in Iranian Patients with Sporadic Diffuse Gastric Cancer

INTRODUCTION

The aim of this study was to survey the nucleotide changes and copy number variations (CNV) in the CDH1 gene in Iranian patients with sporadic diffuse gastric cancer (SDGC).

MATERIALS AND METHODS

In this study, 28 patients were examined who upon gastrectomy had been diagnosed with SDGC according to the familial history and histopathological criteria which was confirmed by the pathologist. DNA extraction was performed from formalin-fixed paraffin-embedded tissues using a phenol-chloroform method following xylene deparaffinization. Determination of DNA sequence by Sanger was performed using PCR amplification of 16 exons and boundaries of intron/exon of CDH1 gene. Multiplex ligation-dependent probe amplification (MLPA) was performed on patients with pathogenic disorders in the sequence.

RESULTS

In total, patients included 20 males and 8 females. Of all patients, 12 patients were under 45 years old (early onset gastric cancer, EODC) and 16 patients were older. The tumor was diagnosed in the early TNM stage (I, II) in six patients and in late stages (III, IV) in 19 cases. Altogether, 16 variants (three exonic with one new variant and 13 intronic with nine new variants) were found in DNA sequencing of the CDH1 gene in five samples. Also, using MLPA, a new duplication in exon 9 and one deletion in exon 2 were detected in two other patients. Altogether, CDH1 variants were identified in seven out of 28 patients (25%).

CONCLUSION

Our study revealed several novel somatic variants in the CDH1 gene in Iranian patients with sporadic diffuse GC. Our data supports the hypothesis that mutations in CDH1 gene, and particularly the mutations we describe, should be considered, even in sporadic cases of gastric cancer. The presence of these mutations in patients raises important issues regarding genetic counseling and diagnostic test in DGC patients.

Circular RNAs and gastrointestinal cancers: Epigenetic regulators with a prognostic and therapeutic role

Both environmental and genetic factors are involved in the initiation and development of gastrointestinal cancer. Covalent closed circular RNAs (circRNAs) are produced by a mechanism called "back-splicing" from mRNAs. They are highly stable and show cell and tissue specific expression patterns. Although some functions such as "microRNA sponge" and "RNA binding protein sponge" have been reported for a small number of circRNAs, the function of thousands of other circRNAs is still unknown. Dysregulation of circRNAs has been reported in many GI cancers and are involved in metastasis and invasion. CircRNAs have been reported to be useful as prognostic markers and targets for developing new treatments. We first describe the properties and biogenesis of circRNAs. We then summarize recent reports about circRNA functions, expression status, and their potential to be used as biomarkers in GI cancers including, gastric cancer, colorectal cancer, esophageal cancer, hepatocellular carcinoma, gallbladder cancer and pancreatic cancer.