Comparison of gene-expression profiles between diffuse- and intestinal-type gastric cancers using a genome-wide cDNA microarray

Cancer-associated fibroblasts promote gastric cancer cell proliferation by paracrine FGF2-driven ribosome biogenesis

The cancer-associated fibroblast (CAF)-derived secretome plays critical roles in tumor progression by remodelling tumor microenvironment. Tumorigenesis is accompanied by the transformation of normal fibroblasts (NF) into CAF, leading to significant changes in their secretome. This work aims to identify the differential components of secretome between NFs and CAFs and reveal their functions in gastric cancer (GC). Firstly, our molecular typing studies and immune infiltration analysis showed that CAF infiltration level was increased and showed a significant association with clinical characteristics and poor prognosis of GC patients. Secondly, RNA-seq analysis revealed that a total of 1531 genes showed significant expression changes between NF and CAF. According to the annotation of the Human Protein Atlas (HPA) database, 147 genes encode secreted proteins, including FGF2. Particularly, the cell co-culture and RNA sequencing studies confirmed that exogenous recombinant FGF2 protein treatment promoted GC cell proliferation by enhancing ribosome biogenesis. The rescue assay showed that CAF-secreted FGF2 protein promotes GC cell growth and proliferation in a FGFR1-dependent manner. Our finding provides evidence that targeting blockade of CAF-derived FGF2 protein might be a promising treatment for GC.

Neoadjuvant camrelizumab and apatinib combined with chemotherapy versus chemotherapy alone for locally advanced gastric cancer: a multicenter randomized phase 2 trial

Prospective evidence regarding the combination of programmed cell death (PD)-1 and angiogenesis inhibitors in treating locally advanced gastric cancer (LAGC) is limited. In this multicenter, randomized, phase 2 trial (NCT04195828), patients with gastric adenocarcinoma (clinical T2-4N + M0) were randomly assigned (1:1) to receive neoadjuvant camrelizumab and apatinib combined with nab-paclitaxel plus S-1 (CA-SAP) or chemotherapy SAP alone (SAP) for 3 cycles. The primary endpoint was the major pathological response (MPR), defined as <10% residual tumor cells in resection specimens. Secondary endpoints included R0 resection rate, radiologic response, safety, overall survival, and progression-free survival. The modified intention-to-treat population was analyzed (CA-SAP [n = 51] versus SAP [n = 53]). The trial has met pre-specified endpoints. CA-SAP was associated with a significantly higher MPR rate (33.3%) than SAP (17.0%, P = 0.044). The CA-SAP group had a significantly higher objective response rate (66.0% versus 43.4%, P = 0.017) and R0 resection rate (94.1% versus 81.1%, P = 0.042) than the SAP group. Nonsurgical grade 3-4 adverse events were observed in 17 patients (33.3%) in the CA-SAP group and 14 (26.4%) in the SAP group. Survival results were not reported due to immature data. Camrelizumab and apatinib combined with chemotherapy as a neoadjuvant regimen was tolerable and associated with favorable responses for LAGC.

PI3K/AKT/mTOR inhibitors as potential extracellular matrix modulators for targeting EMT subtype gastric tumors

Targeting the extracellular matrix (ECM) is considered as a promising strategy in cancer therapeutics. This study was designed to identify the potential ECM modulators for gastric cancer therapeutics. Exploration of the expression profiles of gastric tumors revealed the elevated expression of ECM genes in gastric tumor tissues compared to the adjacent normal tissues with increased expression in diffuse subtype gastric tumors and specifically in epithelial to mesenchymal transition (EMT) molecular subtype tumors. Consensus ECM gene set was derived from the expression profiles of gastric tumors. The correlative analysis was performed between the expression pattern of the ECM gene set and the drug sensitivity pattern of a panel of drugs across gastric cancer cell lines. Negative correlation between the expression of ECM genes and sensitivity of a number of drugs targeting PI3K/mTOR signaling, chromatin histone acetylation and ABL signaling was observed. These pathways are known for their role in cell-mediated adhesion, differentiation and epithelial to mesenchymal transition. The current results reveal the possibility of using PI3K/AKT/mTOR modulators for targeted gastric cancer therapy in patients with dysregulated ECM.

Activation of hypermethylated P2RY1 mitigates gastric cancer by promoting apoptosis and inhibiting proliferation

The P2RY1 receptor is known to cause cancer by activating the ERK signal pathway, and its DNA methylation status and corresponding regulatory mechanism remain unknown. This study used the DNA methylation chip to profile the genome-wide DNA methylation level in gastric cancer tissues. The proliferation and apoptosis of the SGC7901 gastric cancer cell line were determined after treatment with a selective P2RY1 receptor agonist, MRS2365. The promoter region of P2RY1 was found to be highly methylated with four hypermethylated sites (|Δβ value| > 0.2) in diffuse gastric cancer and was validated by bioinformatics analysis in the TCGA database. Also, immunohistochemical staining data obtained from the HPA database demonstrated the downregulated expression of proteins encoded by P2RY1 in stomach cancer tissue. The analysis of MRS2365-treated cells by annexin V/propidium iodide staining and caspase-3 activity assays indicated the induction of apoptosis in SGC7901 cells. The P2RY1 receptor activation in human SGC7901 gastric cancer cells via the MRS2365 agonist induced apoptosis and reduced cell growth. High DNA methylation in the promoter region of P2RY1 might have contributed to the reduced expression of P2RY1's mRNA, which was likely responsible for the "aggressive" nature of the diffuse gastric cancer.

Multilevel proteomic analyses reveal molecular diversity between diffuse-type and intestinal-type gastric cancer

Diffuse-type gastric cancer (DGC) and intestinal-type gastric cancer (IGC) are the major histological types of gastric cancer (GC). The molecular mechanism underlying DGC and IGC differences are poorly understood. In this research, we carry out multilevel proteomic analyses, including proteome, phospho-proteome, and transcription factor (TF) activity profiles, of 196 cases covering DGC and IGC in Chinese patients. Integrative proteogenomic analysis reveals ARIDIA mutation associated with opposite prognostic effects between DGC and IGC, via diverse influences on their corresponding proteomes. Systematical comparison and consensus clustering analysis identify three subtypes of DGC and IGC, respectively, based on distinct patterns of the cell cycle, extracellular matrix organization, and immune response-related proteins expression. TF activity-based subtypes demonstrate that the disease progressions of DGC and IGC were regulated by SWI/SNF and NFKB complexes. Furthermore, inferred immune cell infiltration and immune clustering show Th1/Th2 ratio is an indicator for immunotherapeutic effectiveness, which is validated in an independent GC anti-PD1 therapeutic patient group. Our multilevel proteomic analyses enable a more comprehensive understanding of GC and can further advance the precision medicine.

The diverse repertoire of ISG15: more intricate than initially thought

ISG15, the product of interferon (IFN)-stimulated gene 15, is the first identified ubiquitin-like protein (UBL), which plays multifaceted roles not only as a free intracellular or extracellular molecule but also as a post-translational modifier in the process of ISG15 conjugation (ISGylation). ISG15 has only been identified in vertebrates, indicating that the functions of ISG15 and its conjugation are restricted to higher eukaryotes and have evolved with IFN signaling. Despite the highlighted complexity of ISG15 and ISGylation, it has been suggested that ISG15 and ISGylation profoundly impact a variety of cellular processes, including protein translation, autophagy, exosome secretion, cytokine secretion, cytoskeleton dynamics, DNA damage response, telomere shortening, and immune modulation, which emphasizes the necessity of reassessing ISG15 and ISGylation. However, the underlying mechanisms and molecular consequences of ISG15 and ISGylation remain poorly defined, largely due to a lack of knowledge on the ISG15 target repertoire. In this review, we provide a comprehensive overview of the mechanistic understanding and molecular consequences of ISG15 and ISGylation. We also highlight new insights into the roles of ISG15 and ISGylation not only in physiology but also in the pathogenesis of various human diseases, especially in cancer, which could contribute to therapeutic intervention in human diseases.

Identification of Ubiquitin-Related Gene-Pair Signatures for Predicting Tumor Microenvironment Infiltration and Drug Sensitivity of Lung Adenocarcinoma

Simple Summary

Lung adenocarcinoma (LUAD) has a high mortality and incidence rate. The therapeutic efficacy of LUAD varies with the individual heterogeneity of the tumor microenvironment (TME). It is necessary to explore more biomarkers and targets to improve the prognosis of patients. Ubiquitination pathways are involved in the biological process of regulating the anti-tumor immunity of immune cells and immunosuppression of tumor cells in the TME of patients. In this study, we clarified the characteristics of ubiquitin-related gene pairs (UbRGPs) and identified the relationship between the status of the TME and UbRGPs of patients with LUAD. A prognostic signature based on six UbRGPs was established, which performed well in predicting the immune infiltration and tumor mutation burden (TMB) in the TME and the response of LUAD to immuno-, chemo-, and targeted therapy. In conclusion, the UbRGPs signature is an independent prognostic indicator and has great potential in assisting the clinical therapy for patients with LUAD.

Abstract

Lung adenocarcinoma (LUAD) is a common pathological type of lung cancer worldwide, and new biomarkers are urgently required to guide more effective individualized therapy for patients. Ubiquitin-related genes (UbRGs) partially participate in the initiation and progression of lung cancer. In this study, we used ubiquitin-related gene pairs (UbRGPs) in tumor tissues to access the function of UbRGs in overall survival, immunocyte infiltration, and tumor mutation burden (TMB) of patients with LUAD from The Cancer Genome Atlas (TCGA) database. In addition, we constructed a prognostic signature based on six UbRGPs and evaluated its performance in an internal (TCGA testing set) and an external validation set (GSE13213). The prognostic signature revealed that risk scores were negatively correlated with the overall survival, immunocyte infiltration, and expression of immune checkpoint inhibitor-related genes and positively correlated with the TMB. Patients in the high-risk group showed higher sensitivity to partially targeted and chemotherapeutic drugs than those in the low-risk group. This study contributes to the understanding of the characteristics of UbRGPs in LUAD and provides guidance for effective immuno-, chemo-, and targeted therapy.

Diffuse gastric cancer: Emerging mechanisms of tumor initiation and progression

Gastric cancer is globally the fourth leading cause of cancer-related deaths. Patients with diffuse-type gastric cancer (DGC) particularly have a poor prognosis that only marginally improved over the last decades, as conventional chemotherapies are frequently ineffective and specific therapies are unavailable. Early-stage DGC is characterized by intramucosal lesions of discohesive cells, which can be present for many years before the emergence of advanced DGC consisting of highly proliferative and invasive cells. The mechanisms underlying the key steps of DGC development and transition to aggressive tumors are starting to emerge. Novel mouse- and organoid models for DGC, together with multi-omic analyses of DGC tumors, revealed contributions of both tumor cell-intrinsic alterations and gradual changes in the tumor microenvironment to DGC progression. In this review, we will discuss how these recent findings are leading towards an understanding of the cellular and molecular mechanisms responsible for DGC initiation and malignancy, which may provide opportunities for targeted therapies.

Peroxisome proliferator-activated receptor-α expression is associated with histological type in human gastric carcinoma

Gastric carcinoma is one of the most common types of cancer worldwide and a leading cause of cancer-related mortality. Gastric carcinoma is histologically subdivided into differentiated and undifferentiated carcinoma, with the latter including poorly differentiated carcinoma and signet ring cell carcinoma (SRCC). Poorly differentiated carcinoma and SRCC have a worse prognosis compared with differentiated carcinoma. Peroxisome proliferator-activated receptors (PPARs) are nuclear hormone receptors and the PPAR-α subtype regulates important cellular functions, including cell proliferation, energy metabolism, oxidative stress, immune responses and cell differentiation. The aim of the present study was to elucidate the associations between clinicopathological factors and PPAR-α expression in patients with gastric carcinoma. The immunohistochemical staining of specimens obtained from 57 patients showed that PPAR-α expression was slightly weaker in undifferentiated carcinoma than in differentiated carcinoma (P<0.01). PPAR-α expression also significantly differed between poorly differentiated carcinoma (both positive and negative: 14/20, 70%) and SRCC (not expressed: 0/7, 0%) (P<0.01). However, PPAR-α expression was not significantly affected by age, lymph node invasion, venous invasion, lymph node metastasis, depth of invasion or stage. Collectively, the present results demonstrated that the downregulated expression of PPAR-α may play a key role in the biological transformation of tumors. Therefore, PPAR-α appears to be an important protein related to histology and may hold promise as a prognostic marker. Further studies with a larger number of subjects are needed to elucidate the relationship between PPAR-α expression and tumor progression and to analyze long-term clinical survival.

Single-cell analysis of gastric pre-cancerous and cancer lesions reveals cell lineage diversity and intratumoral heterogeneity

Single-cell transcriptomic profiles analysis has proposed new insights for understanding the behavior of human gastric cancer (GC). GC offers a unique model of intratumoral heterogeneity. However, the specific classes of cells involved in carcinogenetic passage, and the tumor microenvironment of stromal cells was poorly understood. We characterized the heterogeneous cell population of precancerous lesions and gastric cancer at the single-cell resolution by RNA sequencing. We identified 10 gastric cell subtypes and showed the intestinal and diffuse-type cancer were characterized by different cell population. We found that the intestinal and diffuse-type cancer cells have the differential metaplastic cell lineages: intestinal-type cancer cells differentiated along the intestinal metaplasia lineage while diffuse-type cancer cells resemble de novo pathway. We observed an enriched CCND1 mutation in premalignant disease state and discovered cancer-associated fibroblast cells harboring pro-stemness properties. In particular, tumor cells could be categorized into previously proposed molecular subtypes and harbored specific subtype of malignant cell with high expression level of epithelial-myofibroblast transition which was correlated with poor clinical prognosis. In addition to intratumoral heterogeneity, the analysis revealed different cellular lineages were responsible for potential carcinogenetic pathways. Single-cell transcriptomes analysis of gastric pre-cancerous lesions and cancer may provide insights for understanding GC cell behavior, suggesting potential targets for the diagnosis and treatment of GC.

NF-Y subunits overexpression in gastric adenocarcinomas (STAD)

NF-Y is a pioneer transcription factor-TF-formed by the Histone-like NF-YB/NF-YC subunits and the regulatory NF-YA. It binds to the CCAAT box, an element enriched in promoters of genes overexpressed in many types of cancer. NF-YA is present in two major isoforms-NF-YAs and NF-YAl-due to alternative splicing, overexpressed in epithelial tumors. Here we analyzed NF-Y expression in stomach adenocarcinomas (STAD). We completed the partitioning of all TCGA tumor samples (450) according to molecular subtypes proposed by TCGA and ACRG, using the deep learning tool DeepCC. We analyzed differentially expressed genes-DEG-for enriched pathways and TFs binding sites in promoters. CCAAT is the predominant element only in the core group of genes upregulated in all subtypes, with cell-cycle gene signatures. NF-Y subunits are overexpressed, particularly NF-YA. NF-YAs is predominant in CIN, MSI and EBV TCGA subtypes, NF-YAl is higher in GS and in the ACRG EMT subtypes. Moreover, NF-YAlhigh tumors correlate with a discrete Claudinlow cohort. Elevated NF-YB levels are protective in MSS;TP53+ patients, whereas high NF-YAl/NF-YAs ratios correlate with worse prognosis. We conclude that NF-Y isoforms are associated to clinically relevant features of gastric cancer.

Construction and Validation of a Novel Prognostic Signature for Intestinal Type of Gastric Cancer

Background

Intestinal type of gastric cancer (IGC) is the largest subtype of gastric cancer (GC) by Lauren classification. The purpose of this present study was to construct a prognostic signature for IGC patients, based on the high-grade dysplasia (HGD) and IGC tissues, to improve and enhance the prognostic accuracy.

Methods

The microarray datasets and associated clinical characteristics of HGD and IGC were obtained from the Gene Expression Omnibus (GEO) database. Based on the differential expression analysis between HGD and IGC, the prognostic-related differential expression genes (DEGs) were identified in a training set by univariate COX regression analysis. The least absolute shrinkage and selection operator (LASSO) regression was used to construct an optimal prognostic signature. The enrichment analysis was performed by using Gene Set Enrichment Analysis (GSEA). The performance of the nomogram was assessed by the calibration curve and concordance index (C-index). The results were validated by using a testing set.

Results

We identified 35 prognostic-related DGEs in the training set. The nine-gene signature was established by LASSO analysis. The nine-gene signature was an independent risk factor in both the training and testing sets. The areas under the curve (AUC) values of receiver operating characteristic (ROC) analysis were 0.733 and 0.700 for the training and testing sets, respectively. In GSEA analysis, the gene expression in high-risk group was enriched in hedgehog signaling, epithelial mesenchymal transition, and angiogenesis. The nomogram for IGC showed good performance with C-index of 0.81 (95% CI: 0.76-0.86) and 0.70 (95% CI: 0.63-0.77) in the training and testing sets, respectively.

Conclusion

We identified and verified a nine-gene signature for the prognostic prediction of IGC patients, which might identify subgroups of IGC patients and select more suitable therapeutic options.

A blood-based transcriptomic signature for noninvasive diagnosis of gastric cancer

BACKGROUND

Delayed detection of tumours contributes to poor prognosis in patients with gastric cancer (GC). The invasive nature of endoscopy and the absence of an effective serum markers highlight the need to develop novel, noninvasive biomarkers.

METHODS

We performed biomarker discovery and validation to identify candidate genes in three gene expression data sets. After validating the gene panel in clinical tissues, we translated the gene panel into serum samples by performing training and validation in 89 samples from GC patients and 54 from healthy donors in two independent cohorts.

RESULTS

We identified a nine-gene panel in the discovery phase, with subsequent validation in tissue specimens. Using a serum training cohort, we developed a 5-gene risk prediction formulae for the diagnosis of GC; bootstrapped analysis exhibited an AUC of 0.896. We validated this 5-gene biomarker panel using an independent serum cohort, yielding an AUC of 0.947. This biomarker panel successfully identified GC, regardless of tumour histology. Notably, biomarker performance for detection of stage 1 and 2 GC displayed an AUC of 0.928 and 0.980 in both serum cohorts.

CONCLUSIONS

We identified a novel 5-gene biomarker panel for noninvasive diagnosis of GC, which might serve as a potential diagnostic tool for early detection.

Recent advances of miRNAs in the development and clinical application of gastric cancer

Gastric cancer (GC) is one of the most common malignant tumors. The mechanism of how GC develops is vague, and therapies are inefficient. The function of microRNAs (miRNAs) in tumorigenesis has attracted the attention from many scientists. During the development of GC, miRNAs function in the regulation of different phenotypes, such as proliferation, apoptosis, invasion and metastasis, drug sensitivity and resistance, and stem-cell-like properties. MiRNAs were evaluated for use in diagnostic and prognostic predictions and exhibited considerable accuracy. Although many problems exist for the application of therapy, current studies showed the antitumor effects of miRNAs. This paper reviews recent advances in miRNA mechanisms in the development of GC and the potential use of miRNAs in the diagnosis and treatment of GC.

Epigenetics and therapeutic targets in gastrointestinal malignancies

Gastrointestinal (GI) malignancies account for substantial mortality and morbidity worldwide. They are generally promoted by dysregulated signal transduction and epigenetic pathways, which are controlled by specific enzymes. Recent studies demonstrated that histone deacetylases (HDACs) together with DNA methyltransferases (DNMTs) have crucial roles in the signal transduction/epigenetic pathways in GI regulation. In this review, we discuss various enzyme targets and their functional mechanisms responsible for the regulatory processes of GI malignancies. We also discuss the epigenetic therapeutic targets that are mainly facilitated by DNMT and HDAC inhibitors, which have functional consequences and clinical outcomes for GI malignancies.

Interferon-stimulated gene 15 accelerates replication fork progression inducing chromosomal breakage

DNA replication is highly regulated by the ubiquitin system, which plays key roles upon stress. The ubiquitin-like modifier ISG15 (interferon-stimulated gene 15) is induced by interferons, bacterial and viral infection, and DNA damage, but it is also constitutively expressed in many types of cancer, although its role in tumorigenesis is still largely elusive. Here, we show that ISG15 localizes at the replication forks, in complex with PCNA and the nascent DNA, where it regulates DNA synthesis. Indeed, high levels of ISG15, intrinsic or induced by interferon-β, accelerate DNA replication fork progression, resulting in extensive DNA damage and chromosomal aberrations. This effect is largely independent of ISG15 conjugation and relies on ISG15 functional interaction with the DNA helicase RECQ1, which promotes restart of stalled replication forks. Additionally, elevated ISG15 levels sensitize cells to cancer chemotherapeutic treatments. We propose that ISG15 up-regulation exposes cells to replication stress, impacting genome stability and response to genotoxic drugs.

Unsupervised Hierarchical Clustering Identifies Immune Gene Subtypes in Gastric Cancer

Objectives: The pathogenesis of heterogeneity in gastric cancer (GC) is not clear and presents as a significant obstacle in providing effective drug treatment. We aimed to identify subtypes of GC and explore the underlying pathogenesis. Methods: We collected two microarray datasets from GEO (GSE84433 and GSE84426), performed an unsupervised cluster analysis based on gene expression patterns, and identified related immune and stromal cells. Then, we explored the possible molecular mechanisms of each subtype by functional enrichment analysis and identified related hub genes. Results: First, we identified three clusters of GC by unsupervised hierarchical clustering, with average silhouette width of 0.96, and also identified their related representative genes and immune cells. We validated our findings using dataset GSE84426. Subtypes associated with the highest mortality (subtype 2 in the training group and subtype C in the validation group) showed high expression of SPARC, COL3A1, and CCN. Both subtypes also showed high infiltration of fibroblasts, endothelial cells, hematopoietic stem cells, and a high stromal score. Furthermore, subtypes with the best prognosis (subtype 3 in the training group and subtype A in the validation group) showed high expression of FGL2, DLGAP1-AS5, and so on. Both subtypes also showed high infiltration of CD4⁺ T cells, CD8⁺ T cells, NK cells, pDC, macrophages, and CD4⁺ T effector memory cells. Conclusion: We found that GC can be classified into three subtypes based on gene expression patterns and cell composition. Findings of this study help us better understand the tumor microenvironment and immune milieu associated with heterogeneity in GC and provide practical information to guide personalized treatment.

More than Meets the ISG15: Emerging Roles in the DNA Damage Response and Beyond

Maintenance of genome stability is a crucial priority for any organism. To meet this priority, robust signalling networks exist to facilitate error-free DNA replication and repair. These signalling cascades are subject to various regulatory post-translational modifications that range from simple additions of chemical moieties to the conjugation of ubiquitin-like proteins (UBLs). Interferon Stimulated Gene 15 (ISG15) is one such UBL. While classically thought of as a component of antiviral immunity, ISG15 has recently emerged as a regulator of genome stability, with key roles in the DNA damage response (DDR) to modulate p53 signalling and error-free DNA replication. Additional proteomic analyses and cancer-focused studies hint at wider-reaching, uncharacterised functions for ISG15 in genome stability. We review these recent discoveries and highlight future perspectives to increase our understanding of this multifaceted UBL in health and disease.

Enhancement of Migration and Invasion of Gastric Cancer Cells by IQGAP3

Although gastric cancer is one of the most common causes of cancer death in the world, mechanisms underlying this type of tumor have not been fully understood. In this study, we found that IQGAP3, a member of the IQGAP gene family, was significantly up-regulated in human gastric cancer starting from the early stages of tumor progression. Overexpression of IQGAP3 in 293T and NIH3T3 cells, which have no endogenous IQGAP3 expression, resulted in morphological change with multiple dendritic-like protrusions and enhanced migration. Overexpression of IQGAP3 also led to reduced cell–cell adhesion in 293T cells, likely as a result of its interactions with e-cadherin or β-catenin proteins. Additionally, IQGAP3 accumulated along the leading edge of migrating cells and at the cleavage furrow of dividing cells. In contrast, suppression of IQGAP3 by short-interfering RNA (siRNA) markedly reduced invasion and anchorage-independent growth of MKN1 and TMK-1 gastric cancer cells. We further confirmed that IQGAP3 interacted with Rho family GTPases, and had an important role in cytokinesis. Taken together, we demonstrated that IQGAP3 plays critical roles in migration and invasion of human gastric cancer cells, and regulates cytoskeletal remodeling, cell migration and adhesion. These findings may open a new avenue for the diagnosis and treatment of gastric cancer.

A population-based study on intestinal and diffuse type adenocarcinoma of the oesophagus and stomach in the Netherlands between 1989 and 2015

AIM

To investigate the nationwide time trends in incidence and survival of oesophageal and gastric adenocarcinomas according to the Laurén classification (intestinal, diffuse and mixed type).

METHODS

All patients diagnosed in the Netherlands with oesophageal or gastric adenocarcinoma between 1989 and 2015 were included. A syntax was developed to determine the histological subtype based on pathology reports as archived in the Dutch pathology registry. These reports were linked to individual data from the Netherlands Cancer Registry. Relative survival was used to assess survival.

RESULTS

The histological subtype could be determined in 18.691 (84.1%) oesophageal and in 32.312 (83.5%) gastric adenocarcinomas. Among these, 79% were intestinal and 21% diffuse type in oesophageal cancers, compared to 55% intestinal and 44% diffuse type in gastric cancers. Relative median survival of intestinal type tumours was longer than that of diffuse type tumours, that is, 12.1 versus 9.4 months for oesophageal carcinomas, and 10.1 versus 7.6 months for gastric carcinomas, respectively. Between 1989 and 2015, the relative median survival of non-metastatic intestinal and diffuse type oesophageal adenocarcinoma improved from 12.0 to 30.0 months, and from 12.0 to 19.2 months, respectively. The same was true for intestinal type gastric carcinoma (from 22.8 to 27.6 months) but for diffuse type gastric carcinoma, the increase was less (from 16.8 to 18.0 months).

CONCLUSION

In this nationwide study, histological subtypes of oesophageal and gastric adenocarcinomas differed in incidence and survival times. These findings may call for a differentiated treatment approach.

The Extracellular Matrix: An Accomplice in Gastric Cancer Development and Progression

The extracellular matrix (ECM) is a dynamic and highly organized tissue structure, providing support and maintaining normal epithelial architecture. In the last decade, increasing evidence has emerged demonstrating that alterations in ECM composition and assembly strongly affect cellular function and behavior. Even though the detailed mechanisms underlying cell-ECM crosstalk are yet to unravel, it is well established that ECM deregulation accompanies the development of many pathological conditions, such as gastric cancer. Notably, gastric cancer remains a worldwide concern, representing the third most frequent cause of cancer-associated deaths. Despite increased surveillance protocols, patients are usually diagnosed at advanced disease stages, urging the identification of novel diagnostic biomarkers and efficient therapeutic strategies. In this review, we provide a comprehensive overview regarding expression patterns of ECM components and cognate receptors described in normal gastric epithelium, pre-malignant lesions, and gastric carcinomas. Important insights are also discussed for the use of ECM-associated molecules as predictive biomarkers of the disease or as potential targets in gastric cancer.

Hospital Utilization in Patients With Gastric Cancer and Factors Affecting In-Hospital Mortality, Length of Stay, and Costs

INTRODUCTION

Although gastric cancer (GC) rates have been declining in the United States, it continues to be a major cause of morbidity. This study examined trends in hospital admissions, in-hospital mortality, length of stay (LOS), and inpatient costs related to GC. In addition, various factors associated with in-hospital mortality, LOS, and inpatient costs were examined.

METHODS

National inpatient sample-the largest publicly available all-payer inpatient care database-was interrogated to obtain information about various demographic and hospital-related factors (including those mentioned above) in patients who were primarily admitted for GC between the years 1998 to 2013. These trends were analyzed. Multivariate analysis was also performed to identify risk factors associated with LOS, costs, and mortality.

RESULTS

A total of 679,330 hospital discharges with the principal diagnosis of GC were obtained. Hospital stays increased by approximately 340 stays per year (±110; P=0.00079). However, inpatient mortality rate and LOS declined by 0.36% per year (±0.024%; P<0.0001), and 0.11 days per year (±0.01; P<0.0001), respectively. The inpatient charges have increased at the rate of $3241 per year (±133.3; P<0.0001). Differences in mortality rate, LOS, and inpatient costs were affected by multiple factors.

CONCLUSIONS

Despite the overall decline in GC incidence, the incidence of hospitalizations per 100,000 US population related to GC did not change significantly. Although LOS and mortality declined, inpatient charges increased over the study period.

Sox11 promotes head and neck cancer progression via the regulation of SDCCAG8

Background

SOX11 is a transcription factor that plays an important role in mantle cell lymphoma development. However, its functional role in head and neck squamous cell carcinoma (HNSCC) remains unknown.

Methods

Protein expression was measured with Western blotting, immunohistochemistry or quantitative proteomics, and gene expression was measured with quantitative RT-PCR. Functional role of SOX11 in HNSCC was evaluated with MTS/apoptosis, migration, invasion assays and a xenograft model. A SOX11-targeting gene, SDCCAG8, was confirmed with chromatin immunoprecipitation (ChIP), luciferase reporter and rescue assays.

Results

SOX11 was up-regulated in recurrent versus primary HNSCC and in highly invasive versus low invasive HNSCC cell lines. Silencing SOX11 in HNSCC cell lines significantly inhibited the cell proliferation, migration, invasion and resistance to Cisplatin, and vice versa. Quantitative proteomic analysis of SOX11-silencing HNSCC cells revealed a number of differentially expressed proteins, including a down-regulated tumor antigen SDCCAG8. Silencing of SDCCAG8 in HNSCC cells also significantly inhibited the cell proliferation, migration and invasion, and vice versa. ChIP assays demonstrated that endogenous SOX11 strongly bound to Sdccag8 gene promoter in highly invasive HNSCC cells. When over-expressed in low invasive HNSCC cells, wild type SOX11 but not mutant SOX11 induced the promoter activity of Sdccag8 and significantly induced the expression of SDCCAG8. However, exogenous mutant SOX11 abolished the expression of SDCCAG8 in highly invasive HNSCC cells. In addition, the inhibitory effects of SOX11 knockdown were partially rescued by over-expression of SDCCAG8 in HNSCC cells.

Conclusion

Collectively, our findings indicate SOX11 promotes HNSCC progression via the regulation of SDCCAG8.

Electronic supplementary material

The online version of this article (10.1186/s13046-019-1146-7) contains supplementary material, which is available to authorized users.

Gene regulatory network construction identified NFYA as a diffuse subtype-specific prognostic factor in gastric cancer

Lauren classification is a pathology-based gastric cancer (GC) subtyping system, which is widely used in the clinical treatment of patients with GC. However, genome-scale molecular characteristics to distinguish between diffuse (DF) and intestinal (IT) GC remain incompletely characterized, particularly at the transcriptional regulatory level. In the present study, gene regulatory networks were constructed using the Passing Attributes between Networks for Data Assimilation (PANDA) algorithm for DF, IT and mixed GC. The results indicated that >85% of transcription factor (TF)-target edges were shared among all three GC subtypes. In TF enrichment analysis, 13 TFs, including nuclear transcription factor Y subunit α (NFYA) and forkhead box L1, were activated in DF GC, whereas 8 TFs, including RELA proto-oncogene and T-cell leukemia homeobox 1 (TLX1), were activated in IT GC. Out of these identified TFs, NFYA [Hazard ratio (HR) (95% confidence interval, CI)=0.560 (0.349, 0.900), P=0.017] and sex determining region Y [HR (95% CI)=0.603 (0.375, 0.969), P=0.037] were identified as independent prognostic factors in DF GC, but not in IT GC, whereas TLX1 [HR (95% CI)=0.547 (0.321, 0.9325), P=0.027] was identified as an independent prognostic factor in IT GC, but not in DF GC. Verification at the cellular level was also performed; interference of NFYA expression using small interfering RNA in MGC803 cells (DF GC-derived cells) markedly inhibited cell growth and colony formation. Similar effects were also detected in SGC-7901 cells (IT GC-derived cells), but to a lesser extent. In conclusion, identified gene regulatory networks differed between distinct GC subtypes, in which the same TFs had different biological effects. Specifically, NFYA was identified as a DF subtype-specific independent prognostic factor in GC.

Up-Regulation of miR-21, miR-25, miR-93, and miR-106b in Gastric Cancer

Background:

Differential expression profile of microRNAs (miRNAs) could be a diagnosis signature for monitoring gastric cancer (GC) progression. In this study, we focus on the comparison of expression levels of miR-21, miR-25, miR-93, miR-106b, and miR-375 during the sequential pattern of GC development, including normal gastric, gastric dysplasia, and GC sample.

Methods:

We used SYBR Green-based quantitative-PCR to quantify miRNAs expression.

Results:

Our analysis revealed the increased expression levels of miR-21 (p = 0.034), miR-25 (p = 0.0003), miR-93 (p = 0.0406), and miR-106b (p = 0.023) in GC samples. In addition, GC patients with positive lymph node metastasis showed the up-regulation of miR-25, miR-93, and miR-106b (p < 0.05).

Conclusion:

Our findings suggested that the expression of miR-21, miR-25, miR-93, and miR-106b altered in GC, and some of them may be further investigated as biomarkers for GC early detection and prognosis prediction.

hTERT promotes tumor progression by enhancing TSPAN13 expression in osteosarcoma cells

Telomerase complex maintains the length of the telome, cbre, and protects erosion of the physical ends of the eukaryotic chromosome in all actively dividing cells including cancer cells. Telomerase activation extends the lifespan of cells in culture by maintaining the length of the telomere. Compared to terminally differentiated somatic cells, telomerase activity remains high in over 90% of cancer cells. It has now become clear that the role of telomerase is much more complex than just telomere lengthening. The remaining 10% of cancers deploy ALT (alternative lengthening of telomeres) pathway to maintain telomere length. Telomerase inhibitors offer a good therapeutic option. Also, telomerase-associated molecules can be targeted provided their roles are clearly established. In any case, it is necessary to understand the major role of telomerase in cancer cells. Many studies have already been done to explore gene profiling of a telomerase positive cell by knocking down expression of hTERT (telomerase reverse transcriptase). To complement these studies, we performed global gene profiling of a telomerase negative cell by ectopically expressing hTERT and studied changes in the global gene expression patterns. Analysis of microarray data for telomerase negative cells ectopically expressing telomerase showed 76 differentially regulated genes, out of which 39 genes were upregulated, and 37 were downregulated. Three upregulated genes such as TSPAN13, HMGCS2, DLX5, and three downregulated genes like DHRS2, CRYAB, and PDLIM1 were validated by real-time PCR. Knocking down of TSAPN13 in hTERT overexpressing U2OS cells enhanced the apoptosis of the cells. TSPAN13 knockdown in these cells suppressed mesenchymal properties and enhanced epithelial character.

ISG15 in the tumorigenesis and treatment of cancer: An emerging role in malignancies of the digestive system

The interferon-stimulated gene 15 ubiquitin-like modifier (ISG15) encodes an IFN-inducible, ubiquitin-like protein. The ISG15 protein forms conjugates with numerous cellular proteins that are involved in a multitude of cellular functions, including interferon-induced immune responses and the regulation of cellular protein turnover. The expression of ISG15 and ISG15-mediated conjugation has been implicated in a wide range of human tumors and cancer cell lines, but the roles of ISG15 in tumorigenesis and responses to anticancer treatments remain largely unknown. In this review, we discuss the findings of recent studies with regard to the role of ISG15 pathways in cancers of the digestive system.

Silencing of Discoidin Domain Receptor-1 (DDR1) Concurrently Inhibits Multiple Steps of Metastasis Cascade in Gastric Cancer

Accumulating evidence suggests that a unique set of receptor tyrosine kinases, known as discoidin domain receptors (DDRs), plays a role in cancer progression by interacting with the surrounding collagen matrix. In this study, we investigated the expression and role of DDR1 in human gastric cancer metastasis. Proliferation, migration, invasion, and tube formation assays were conducted in DDR1-expressing MKN74 gastric cancer cells and corresponding DDR1-silenced cells. The effects of DDR1 on tumor growth and metastasis were examined in orthotopically implanted and experimental liver metastasis models in nude mice. The expression of DDR1 in surgical specimens was analyzed by immunohistochemistry. DDR1 was expressed in human gastric cancer cell lines, and its expression in human gastric tumors was associated with poor prognosis. Among seven gastric cancer cell lines, MKN74 expressed the highest levels of DDR1. DDR1-silenced MKN74 cells showed unaltered proliferation activity. In contrast, migration, invasion, and tube formation were significantly reduced. When examined in an orthotopic nude mouse model, DDR1-silenced implanted tumors significantly reduced angiogenesis and lymphangiogenesis, thereby leading to reductions in lymph node metastasis and liver metastasis. In a model of experimental liver metastasis, DDR1-silenced cells almost completely inhibited liver colonization and metastasis. DDR1 deficiency led to reduced expression of the genes encoding vascular endothelial growth factor (VEGF)-A, VEGF-C, and platelet-derived growth factor-B. These results suggest that DDR1 is involved in gastric cancer tumor progression and that silencing of DDR1 inhibits multiple steps of the gastric cancer metastasis process.

Ubiquitin-like modifications in the DNA damage response

Genomic DNA is damaged at an extremely high frequency by both endogenous and environmental factors. An improper response to DNA damage can lead to genome instability, accelerate the aging process and ultimately cause various human diseases, including cancers and neurodegenerative disorders. The mechanisms that underlie the cellular DNA damage response (DDR) are complex and are regulated at many levels, including at the level of post-translational modification (PTM). Since the discovery of ubiquitin in 1975 and ubiquitylation as a form of PTM in the early 1980s, a number of ubiquitin-like modifiers (UBLs) have been identified, including small ubiquitin-like modifiers (SUMOs), neural precursor cell expressed, developmentally down-regulated 8 (NEDD8), interferon-stimulated gene 15 (ISG15), human leukocyte antigen (HLA)-F adjacent transcript 10 (FAT10), ubiquitin-fold modifier 1 (UFRM1), URM1 ubiquitin-related modifier-1 (URM1), autophagy-related protein 12 (ATG12), autophagy-related protein 8 (ATG8), fan ubiquitin-like protein 1 (FUB1) and histone mono-ubiquitylation 1 (HUB1). All of these modifiers have known roles in the cellular response to various forms of stress, and delineating their underlying molecular mechanisms and functions is fundamental in enhancing our understanding of human disease and longevity. To date, however, the molecular mechanisms and functions of these UBLs in the DDR remain largely unknown. This review summarizes the current status of PTMs by UBLs in the DDR and their implication in cancer diagnosis, therapy and drug discovery.

The novel long noncoding RNA RP11-357H14.17 acts as an oncogene by promoting cell proliferation and invasion in diffuse-type gastric cancer

Current evidence indicates that long noncoding RNAs (lncRNAs) play pivotal roles in human cancers. The present study aims to assess differentially expressed lncRNAs related to diffuse-type gastric carcinoma (DGC). Next-generation RNA sequencing was carried out to detect aberrantly expressed lncRNAs in DGC. Real-time polymerase chain reaction (RT-PCR) was performed to evaluate RP11–357H14.17 gene expression levels in DGC cell lines/tissues comparatively with normal gastric epithelial cell lines and adjacent normal tissues. The associations of RP11–357H14.17 expression levels with the clinicopathological features were also analyzed. The regulatory effects of RP11–357H14.17 on the biological behaviors of DGC cells were evaluated by MTT, colony formation assays, flow cytometry for apoptosis, wound healing assay, and transwell migration and invasion assays. RP11–357H14.17 expression was remarkably increased in DGC tissues and cell lines compared with normal gastric epithelial cells and adjacent normal tissues. High levels of RP11–357H14.17 were associated with increased tumor size, deeper depth of invasion, lymphatic metastasis, and advanced pathological stage. Further experiments demonstrated that the DGC cells MGC-803 transfected with si-RP11–357H14.17 showed reduced cell proliferation, migration, invasion, enhanced G1 phase arrest and cell apoptosis. These findings suggest that the novel lncRNA RP11–357H14.17 is associated with poor prognosis, and may serve as a potential prognostic biomarker and target for new antineoplastic therapies in human DGC.

A Downmodulated MicroRNA Profiling in Patients with Gastric Cancer

Objective. Here, we aim to investigate the microRNA (miR) profiling in human gastric cancer (GC). Methods. Tumoral and matched peritumoral gastric specimens were collected from 12 GC patients who underwent routine surgery. A high-throughput miR sequencing method was applied to detect the aberrantly expressed miRs in a subset of 6 paired samples. The stem-loop quantitative real-time polymerase chain reaction (qRT-PCR) assay was subsequently performed to confirm the sequencing results in the remaining 6 paired samples. The profiling results were also validated in vitro in three human GC cell lines (BGC-823, MGC-803, and GTL-16) and a normal gastric epithelial cell line (GES-1). Results. The miR sequencing approach detected 5 differentially expressed miRs, hsa-miR-132-3p, hsa-miR-155-5p, hsa-miR-19b-3p, hsa-miR-204-5p, and hsa-miR-30a-3p, which were significantly downmodulated between the tumoral and peritumoral GC tissues. Most of the results were further confirmed by qRT-PCR, while no change was observed for hsa-miR-30a-3p. The in vitro finding also agreed with the results of both miR sequencing and qRT-PCR for hsa-miR-204-5p, hsa-miR-155-5p, and hsa-miR-132-3p. Conclusion. Together, our findings may serve to identify new molecular alterations as well as to enrich the miR profiling in human GC.

Integrated Analysis Identifies Molecular Signatures and Specific Prognostic Factors for Different Gastric Cancer Subtypes

BACKGROUND

Gastric cancer (GC) is the fifth leading cause of cancer-related deaths worldwide. As an effective and easily performed method, microscopy-based Lauren classification has been widely accepted by gastrointestinal surgeons and pathologists for GC subtyping, but molecular characteristics of different Lauren subtypes were poorly revealed.

METHODS

GSE62254 was used as a derivation cohort, and GSE15459 was used as a validation cohort. The difference between diffuse and intestinal GC on the gene expression level was measured. Gene ontology (GO) enrichment analysis was performed for both subgroups. Hierarchical clustering and heatmap exhibition were also performed. Kaplan-Meier plot and Cox proportional hazards model were used to evaluate survival grouped by the given genes or hierarchical clusters.

RESULTS

A total of 4598 genes were found differentially expressed between diffuse and intestinal GC. Immunity- and cell adhesion-related GOs were enriched for diffuse GC, whereas DNA repair- and cell cycle-related GOs were enriched for intestinal GC. We proposed a 40-gene signature (χ2=30.71, P<.001) that exhibits better discrimination for prognosis than Lauren classification (χ2=12.11, P=.002). FRZB [RR (95% CI)=1.824 (1.115-2.986), P=.017] and EFEMP1 [RR (95% CI)=1.537 (0.969-2.437), P=.067] were identified as independent prognostic factors only in diffuse GC but not in intestinal GC patients. KRT23 [RR (95% CI)=1.616 (0.938-2.785), P=.083] was identified as an independent prognostic factor only in intestinal GC patients but not in diffuse GC patients. Similar results were achieved in the validation cohort.

CONCLUSION

We found that GCs with different Lauren classifications had different molecular characteristics and identified FRZB, EFEMP1, and KRT23 as subtype-specific prognostic factors for GC patients.

Droplet-based microtumor model to assess cell-ECM interactions and drug resistance of gastric cancer cells

Gastric cancer (GC) is a common aggressive malignant tumor with high incidence and mortality worldwide. GC is classified into intestinal and diffuse types according to the histo-morphological features. Because of distinctly different clinico-pathological features, new cancer therapy strategies and in vitro preclinical models for the two pathological variants of GC is necessary. Since extracellular matrix (ECM) influence the biological behavior of tumor cells, we hypothesized that GC might be more similarly modeled in 3D with matrix rather than in 2D. Herein, we developed a microfluidic-based a three-dimensional (3D) in vitro gastric cancer model, with subsequent drug resistance assay. AGS (intestinal type) and Hs746T (diffuse type) gastric cancer cell lines were encapsulated in collagen beads with high cellular viability. AGS exhibited an aggregation pattern with expansive growth, whereas Hs746T showed single-cell-level infiltration. Importantly, in microtumor models, epithelial-mesenchymal transition (EMT) and metastatic genes were upregulated, whereas E-cadherin was downregulated. Expression of ß-catenin was decreased in drug-resistant cells, and chemosensitivity toward the anticancer drug (5-FU) was observed in microtumors. These results suggest that in vitro microtumor models may represent a biologically relevant platform for studying gastric cancer cell biology and tumorigenesis, and for accelerating the development of novel therapeutic targets.

Integrated analysis identified an intestinal-like and a diffuse-like gene sets that predict gastric cancer outcome

The two major histological types of gastric cancer, intestinal and diffuse subtypes, have distinct epidemiological and pathophysiological features and were also suggested to be of diverse clinical outcomes. Although the gene expression spectrum of gastric cancer subtypes has been reported by previous studies, its linkage with gastric cancer clinical features and outcomes remains elusive. We investigated large-sample online gastric cancer datasets for seeking genes correlated with the clinical diversities between gastric cancer intestinal and diffuse subtypes. Genes differently expressed between the two subtypes were assessed by multiple statistical analysis and were testified on cellular level by quantitative RT-PCR. Related genes were combined to generate a risk signature, and their mutual linkages were also explored. Among genes overexpressed in intestinal subtype, ATPIF1, PRDX2, PRKAR2A, and SMC1A were correlated with positive prognosis. Among genes overexpressed in diffuse subtype, DTNA, GPR161, IDS, RHOQ, and TSHZ2 were correlated with negative prognosis. These nine genes were all novel independent prognostic factors. When used in combination as signatures, these two gene sets displayed strong efficacy for prediction of the prognosis and clinical variables in gastric and colorectal cancer. Hence, these two genes sets were respectively defined as the favorable intestinal-like and adverse diffuse-like gene sets. We identified nine novel genes correlated with the clinical diversity between the intestinal and diffuse subtypes of gastric cancer. The malignant changes from the intestinal to diffuse subtype might be due to the reduction of the four intestinal-like genes, as well as the elevation of the five diffuse-like genes.

Annexin A1 sustains tumor metabolism and cellular proliferation upon stable loss of HIF1A

Despite the approval of numerous molecular targeted drugs, long-term antiproliferative efficacy is rarely achieved and therapy resistance remains a central obstacle of cancer care. Combined inhibition of multiple cancer-driving pathways promises to improve antiproliferative efficacy. HIF-1 is a driver of gastric cancer and considered to be an attractive target for therapy. We noted that gastric cancer cells are able to functionally compensate the stable loss of HIF-1α. Via transcriptomics we identified a group of upregulated genes in HIF-1α-deficient cells and hypothesized that these genes confer survival upon HIF-1α loss. Strikingly, simultaneous knock-down of HIF-1α and Annexin A1 (ANXA1), one of the identified genes, resulted in complete cessation of proliferation. Using stable isotope-resolved metabolomics, oxidative and reductive glutamine metabolism was found to be significantly impaired in HIF-1α/ANXA1-deficient cells, potentially explaining the proliferation defect. In summary, we present a conceptually novel application of stable gene inactivation enabling in-depth deconstruction of resistance mechanisms. In theory, this experimental approach is applicable to any cancer-driving gene or pathway and promises to identify various new targets for combination therapies.

Epigenetic modification of TLR4 promotes activation of NF-κB by regulating methyl-CpG-binding domain protein 2 and Sp1 in gastric cancer

Toll-like receptor 4 (TLR4) is important in promoting the immune response in various cancers. Recently, TLR4 is highly expressed in a stage-dependent manner in gastric cancer, but the regulatory mechanism of TLR4 expression has been not elucidated it. Here, we investigated the mechanism underlying regulation of TLR4 expression through promoter methylation and histone modification between transcriptional regulation and silencing of the TLR4 gene in gastric cancer cells. Chromatin immunoprecipitation was carried out to screen for factors related to TLR4 methylation such as MeCP2, HDAC1, and Sp1 on the TLR4 promoter. Moreover, DNA methyltransferase inhibitor 5-aza-deoxycytidine (5-aza-dC) induced demethylation of the TLR4 promoter and increased H3K4 trimethylation and Sp1 binding to reactivate silenced TLR4. In contrast, although the silence of TLR4 activated H3K9 trimethylation and MeCP2 complex, combined treatment with TLR4 agonist and 5-aza-dC upregulated H3K4 trimethylation and activated with transcription factors as Sp1 and NF-κB. This study demonstrates that recruitment of the MeCP2/HDAC1 repressor complex increases the low levels of TLR4 expression through epigenetic modification of DNA and histones on the TLR4 promoter, but Sp1 activates TLR4 high expression by hypomethylation and NF-κB signaling in gastric cancer cells.

A systems biology approach to detect key pathways and interaction networks in gastric cancer on the basis of microarray analysis

The aim of the present study was to explore key molecular pathways contributing to gastric cancer (GC) and to construct an interaction network between significant pathways and potential biomarkers. Publicly available gene expression profiles of GSE29272 for GC, and data for the corresponding normal tissue, were downloaded from Gene Expression Omnibus. Pre‑processing and differential analysis were performed with R statistical software packages, and a number of differentially expressed genes (DEGs) were obtained. A functional enrichment analysis was performed for all the DEGs with a BiNGO plug‑in in Cytoscape. Their correlation was analyzed in order to construct a network. The modularity analysis and pathway identification operations were used to identify graph clusters and associated pathways. The underlying molecular mechanisms involving these DEGs were also assessed by data mining. A total of 249 DEGs, which were markedly upregulated and downregulated, were identified. The extracellular region contained the most significantly over‑represented functional terms, with respect to upregulated and downregulated genes, and the closest topological matches were identified for taste transduction and regulation of autophagy. In addition, extracellular matrix‑receptor interactions were identified as the most relevant pathway associated with the progression of GC. The genes for fibronectin 1, secreted phosphoprotein 1, collagen type 4 variant α‑1/2 and thrombospondin 1, which are involved in the pathways, may be considered as potential therapeutic targets for GC. A series of associations between candidate genes and key pathways were also identified for GC, and their correlation may provide novel insights into the pathogenesis of GC.

Profiling age-related epigenetic markers of stomach adenocarcinoma in young and old subjects

The purpose of our study is to identify epigenetic markers that are differently expressed in the stomach adenocarcinoma (STAD) condition. Based on data from The Cancer Genome Atlas (TCGA), we were able to detect an age-related difference in methylation patterns and changes in gene and miRNA expression levels in young (n = 14) and old (n = 70) STAD subjects. Our analysis identified 323 upregulated and 653 downregulated genes in old STAD subjects. We also found 76 miRNAs with age-related expression patterns and 113 differentially methylated genes (DMGs), respectively. Our further analysis revealed that significant upregulated genes (n = 35) were assigned to the cell cycle, while the muscle system process (n = 27) and cell adhesion-related genes (n = 57) were downregulated. In addition, by comparing gene and miRNA expression with methylation change, we identified that three upregulated genes (ELF3, IL1β, and MMP13) known to be involved in inflammatory responses and cell growth were significantly hypomethylated in the promoter region. We further detected target candidates for age-related, downregulated miRNAs (hsa-mir-124–3, hsa-mir-204, and hsa-mir-125b-2) in old STAD subjects. This is the first report of the results from a study exploring age-related epigenetic biomarkers of STAD using high-throughput data and provides evidence for a complex clinicopathological condition expressed by the age-related STAD progression.

Deregulation of the cell polarity protein Lethal giant larvae 2 (Lgl2) correlates with gastric cancer progression

BACKGROUND

We investigated the roles of Lethal giant larvae 2 (Lgl2), an epithelial cell polarity protein, during gastric carcinogenesis and gastric cancer (GC) progression and evaluated the correlation of Lgl2 with epithelial-mesenchymal transition (EMT) markers.

METHODS

Lgl2 protein and mRNA expression were determined by immunohistochemistry and mRNA in situ hybridization in a large series of GC and preneoplastic lesions. Additionally, expression of 7 EMT markers was examined by immunohistochemistry.

RESULTS

Loss of membrane Lgl2 staining in GC was observed in 347 of 409 GCs. Lgl2 loss was associated with diffuse histological type (P < 0.001), advanced stage (P = 0.021), and worse prognosis (P = 0.047). Furthermore, Lgl2 loss correlated with reduced E-cadherin expression (P < 0.01) and increased expression of vimentin (P < 0.01). Combined analysis of Lgl2 and the EMT markers, S100A4 and MMP2, improved predictions of patient outcomes. During gastric carcinogenesis, membrane expression of Lgl2 was progressively lost in 4 % of normal mucosa, 75 % of intestinal metaplasia, 58 % of gastric dysplasia, 69 % of intestinal type GC, and 96 % of diffuse type GC.

CONCLUSIONS

Our results suggest that Lgl2 loss occurs at an early stage of gastric carcinogenesis and contributes to GC progression.

Decreased ITIH5 expression is associated with poor prognosis in primary gastric cancer

Inter-α-trypsin inhibitors (ITIs) are a family of serine protease inhibitors that comprise one light chain and a variable set of heavy chains (ITI heavy chains, ITIHs). ITIH5 is a new member of the ITIH family that contains two domains conserved in all known ITIHs: vault protein IT and von Willebrand type A. Recent studies suggest that ITIH5 expression may be altered in certain types of cancer. This study aimed to investigate ITIH5 expression in clinical tumor specimens from gastric cancer patients and its prognostic value for gastric cancer. ITIH5 expression was detected in fresh gastric cancer tissues (T) and the matched adjacent non-tumor tissues (ANT) using real-time quantitative reverse transcription-PCR and Western blotting. ITIH5 expression was retrospectively detected in 331 paraffin-embedded, banked samples using immunohistochemical staining. ITIH5 mRNA and protein expression was significantly downregulated in gastric cancer tissues compared to the ANT. There was a significant association between ITIH5 expression and histological grade (P = 0.020), N classification (P = 0.047), and clinical stage (P = 0.011). Patients with low ITIH5 expression had shorter survival compared to those with high ITIH5 expression. Multivariate analysis showed that ITIH5 expression was an independent prognostic factor for overall survival of gastric cancer patients (P = 0.034). Our data suggest that ITIH5 could play an important role in gastric cancer and may serve as a valuable prognostic biomarker and potential molecular therapy target for gastric cancer.

Saracatinib impairs the peritoneal dissemination of diffuse-type gastric carcinoma cells resistant to Met and fibroblast growth factor receptor inhibitors

Diffuse-type gastric carcinomas (DGC) exhibit more aggressive progression and poorer prognosis than intestinal-type and other gastric carcinomas. To identify potential therapeutic targets, we examined protein tyrosine phosphorylation in a panel of DGC and other gastric cancer cell lines. Protein tyrosine phosphorylation was significantly enhanced or altered in DGC cell lines compared with that in other gastric cancer cell lines. Affinity purification and mass spectrometry analysis of tyrosine-phosphorylated proteins identified Met as a protein that is preferentially expressed and phosphorylated in DGC cell lines. Unexpectedly, Met inhibitors blocked cell growth, Met downstream signaling and peritoneal dissemination in vivo in only a subset of cell lines that exhibited remarkable overexpression of Met. Likewise, only cell lines with overexpression of fibroblast growth factor receptor 2 (FGFR2) or phosphorylation of FRS2 were sensitive to an FGFR2 inhibitor. A Src inhibitor saracatinib impaired growth in cell lines that are insensitive to both Met and FGFR2 inhibitors. Saracatinib also effectively impaired peritoneal dissemination of Met-independent and FGFR2-independent SGC cells. Moreover, DGC cell lines exhibited nearly mutually exclusive susceptibility to Met, FGFR and Src inhibitors. These results suggest that DGC have distinct sensitivities to molecular target drugs and that targeting Src is beneficial in the treatment of DGC insensitive to Met and FGFR inhibition.

Epigenetic biomarkers: potential applications in gastrointestinal cancers

Genetics and epigenetics coregulate the cancer initiation and progression. Epigenetic mechanisms include DNA methylation, histone modification, chromatin remodeling, and noncoding RNAs. Aberrant epigenetic modifications play a fundamental role in the formation of gastrointestinal cancers. Advances in epigenetics offer a better understanding of the carcinogenesis and provide new insights into the discovery of biomarkers for diagnosis, and prognosis prediction of human cancers. This review aims to overview the epigenetic aberrance and the clinical applications as biomarkers in gastrointestinal cancers mainly gastric cancer and colorectal cancer.

Converting a microarray signature into a diagnostic test: a trial of custom 74 gene array for clarification and prediction the prognosis of gastric cancer

Background

Gastric cancer (GC) is associated with high mortality rates and an unfavorable prognosis at advanced stages. In addition, there are no effective methods for diagnosing gastric cancer at an early stage or for predicting the outcome for the purpose of selecting patient-specific treatment options. Therefore, it is important to investigate new methods for GC diagnosis.

Methodology/Principal Findings

To facilitate its use in a diagnostic setting, a group of 74 genes with diagnostic and prognostic information was translated into a customized microarray containing a reduced set of 1,042 probes suitable for high throughput processing. In this report, we demonstrate for the first time that the custom mini-array can be used as a reliable diagnostic tool in gastric cancer. With an AUC value of 0.565 (95% CI 0.305-0.825) indicating a perfect test, the sensitivity and specificity of diagnosis from the ROC curve were calculated to be 70% and 80%, respectively.

Conclusions/Significance

The data clearly demonstrate the reproducibility and robustness of the small custom-made microarray. The array is an excellent tool for classifying and predicting the outcome of disease in gastric cancer patients.

FoxM1 promotes glioma cells progression by up-regulating Anxa1 expression

Forkhead box M1 (FoxM1) is a member of the forkhead transcription factor family and is overexpression in malignant gliomas. However, the molecular mechanisms by which FoxM1lead to glioma carcinogenesis and progression are still not well known. In the present study, we show that Anxa1 was overexpression in gliomas and predicted the poor outcome. Furthermore, Anxa1 closely related to the FoxM1 expression and was a direct transcriptional target of FoxM1. Overexpression of FoxM1 up-regulated Anxa1 expression, whereas suppression of FoxM1 expression down-regulated Anxa1 expression in glioma cells. Finally, FoxM1 enhanced the proliferation, migration, and angiogenesis in Anxa1-dependent manner both in vitro and in vivo. Our findings provide both clinical and mechanistic evidences that FoxM1 contributes to glioma development by directly up-regulating Anxa1 expression.