Gastric Carcinoma Samples Research Articles

CDKN2A somatic copy number amplification in normal tissues surrounding gastric carcinoma reduces cancer metastasis risk in droplet digital PCR analysis.

The CDKN2A gene is frequently affected by somatic copy number variations (SCNVs, including deletions and amplifications [SCNdel and SCNamp]) in the cancer genome. Using surgical gastric margin tissue samples (SMs) as the diploid reference in SCNV analysis via CDKN2A/P16-specific real-time PCR (P16-Light), we previously reported that the CDKN2A SCNdel was associated with a high risk of metastasis of gastric carcinoma (GC). However, the status of CDKN2A SCNVs in SMs and their clinical significance have not been reported. Peripheral white blood cell (WBC) and frozen GC and SM tissue samples were collected from patients (n = 80). Droplet digital PCR (ddPCR) was used to determine the copy number (CN) of the CDKN2A gene in tissue samples using paired WBCs as the diploid reference. A novel P16-ddPCR system was initially established with a minimal proportion (or limit, 10%) of the detection of CDKN2A CN alterations. While CDKN2A SCNamp events were detected in both SMs and GCs, fewer CDKN2A SCNdel events were detected in SMs than in GCs (15.0% vs. 41.3%, P = 4.77E-04). Notably, significantly more SCNamp and fewer SCNdel of the CDKN2A gene were detected in SMs from GC patients without metastasis than in those from patients with lymph node metastasis by P16-ddPCR (P = 0.023). The status of CDKN2A SCNVs in SM samples was significantly associated with overall survival (P = 0.032). No cancer deaths were observed among the 11 patients with CDKN2A SCNamp. CDKN2A SCNVs in SMs identified by P16-ddPCR are prevalent and significantly associated with GC metastasis and overall survival.

Identification of gastric signet ring cell carcinoma based on endoscopic images using few-shot learning

BackgroundDeep learning (DL) models perform poorly when there are limited gastric signet ring cell carcinoma (SRCC) samples. Few-shot learning (FSL) can address the small sample problem. MethodsEfficientNetV2-S was first pretrained on ImageNet and then pretrained on esophageal endoscopic images (i.e., base classes: normal vs. early cancer vs. advanced cancer) using transfer learning. Second, images of gastric benign ulcers, adenocarcinoma and SRCC, i.e., novel classes (n = 50 per class), were included. Image features were extracted as vectors using the dual pretrained EfficientNetV2-S. Finally, a k-nearest neighbor classifier was used to identify SRCC. The above proposed 3-way 3-shot FSL framework was conducted in three rounds. ResultsDual pretrained FSL performed better than single pretrained FSL, endoscopists and traditional EfficientNetV2-S models. Dual pretrained FSL obtained the highest accuracy (79.4%), sensitivity (68.8%), recall (68.8%), precision (69.3%) and F1-score (0.691), and the senior endoscopist achieved the highest specificity of 93.6% when identifying SRCC. The macro-AUC and F1-score for dual pretraining (0.763 and 0.703, respectively) were higher than those for single pretraining (0.656 and 0.537, respectively), along with endoscopists and traditional EfficientNetV2-S models. The 2-way 3-shot FSL also performed better. ConclusionThe proposed FSL framework showed practical performance in the differentiation of SRCC on endoscopic images, suggesting the potential of FSL in the computer-aided diagnosis for rare diseases.

The Generation and Application of Monoclonal Antibodies to Detect SAPCD2 Expression in Precancerous and Malignant Gastric Lesions.

Suppressor APC domain containing 2 (SAPCD2) is involved in cell cycle regulation and its mRNA levels are higher in cancer tissues. But, the function of SAPCD2 in cancer development remains unclear. To generate mouse monoclonal antibodies (mAbs) specific to SAPCD2 and thus clarify the function of SAPCD2 in the development of gastric carcinoma (GC). Methods: Purified SAPCD2-GST immunized BALB/c mouse spleen cells were collected and fused with myeloma cells to obtain monoclonal antibody hybridoma. A group of monoclonal antibodies exhibiting high specificity and sensitivity against SAPCD2 has been generated and characterized by IHC, WB, IP, IF, and ELISA. By immunohistochemical analysis, the SAPCD2 expression was evaluated in 228 clinical samples of gastric mucosal lesions, including precancerous lesions and GC samples. We identified a highly specific and sensitive clone of s12 in eukaryotic cells and performed an IHC analysis. We found that 81.3% of 107 GC tissues were SAPCD2-positive, compared with the 26.2% in the matched adjacent normal-appearing tissues (P<0.001). Furthermore, among the 121 gastritis tissues, SAPCD2 was overexpressed in precancerous gastric lesions such as dysplasia (Dys, 78.9%), intestinal metaplasia (IM, 44.7%), and chronic atrophic gastritis (CAG, 6.1%) compared with that in chronic non-atrophic gastritis (CNAG, 3.2%) (P<0.001). The SAPCD2-positivity rate was 81.3% in GC, suggesting that the expression of SAPCD2 increased with the severity of the lesion (P<0.001). In summary, we have described novel monoclonal antibodies against SAPCD2, which are highly expressed in GC tissues and may serve as the basis for an early clinical marker for GC development.

Joint effect of THBS2 and VCAN accelerating the poor prognosis of gastric cancer.

Gastric cancer is the most common malignant tumor of the digestive system. The progression from gastritis to gastric cancer may be related to genetic factors, but the specific molecular mechanism remains unclear. Therefore, an in-depth study of the molecular mechanism of gastritis and gastric cancer is significant. We downloaded two gene profiles, GSE2669 and GSE116312, from the Gene Expression Omnibus (GEO) database. This study aims to apply bioinformatics technology to mine differentially expressed genes (DEGs), DEGs annotation, protein-protein interaction (PPI) network creation, and hub gene identification and expression between gastric cancer patients and gastritis patients. Overall survival analysis of hub genes, analysis by comparative toxicogenomics database for hub genes in gastric cancer, THBS2 and VCAN protein expression by immunohistochemistry for gastric cancer and gastritis as well as design of the biological process (BP) neural network was implemented. The MSLN, SPP1, THBS2, SPARC, FN1, IGFBP7, VCAN were up-regulated in gastric carcinoma samples, while FGA was down-regulated. The protein expression of THBS2 and VCAN in gastric cancer was significantly higher than that in gastritis. VCAN protein expression was positively associated with tumor invasion (P = 0.011) and HER2 overexpression (P = 0.031). Strong correlation among THBS2, VCAN, and gastric cancer based on the BP neural network. THBS2 and VCAN may be potential targets for improving gastric cancer patients' diagnosis and clinical efficacy.

The Role of Long Non-Coding RNA LINC00467 in Gastric Carcinoma: High Proliferation, Migration and Autophagy

The goal of this study is to investigate the role of long non-coding RNA LINC00467 in gastric carcinoma (GC) progression. Differential expressions of LINC00467 in GC samples were detected. By analyzing the follow-up data of recruited GC patients, the influence of LINC00467 on their prognosis was assessed. After knockdown of LINC00467 in SGC7901 and MKN45 cells, cell autophagy was examined by GFP-LC3 puncta assay and Western blot analyses on autophagy-associated genes. Additionally, cell growth and migration were assessed using cell counting kit-8 (CCK-8), 5-ethynyl-2′-deoxyuridine (EdU), and transwell assays. The connection between LINC00467 and miR-18a-5p was studied through a luciferase assay and Pearson correlation analysis. Increased expression of LINC00467 was observed in GC samples and its elevated levels predicted a poor outcome for GC patients. The suppression of LINC00467 reduced the proliferative and migratory capacities of SGC7901 and MKN45 cells. LINC00467 level was closely linked to autophagy activity in GC. The level of miR-18a-5p was decreased in GC tissues and had an inverse correlation with LINC00467, which was established as the target of miR-18a-5p. Upregulated LINC00467 induces growth, metastasis and autophagy activity in GC through negatively regulating miR-18a-5p level, thus leading to the poor prognosis in GC patients.

Vimentin binds to a novel tumor suppressor protein, GSPT1-238aa, encoded by circGSPT1 with a selective encoding priority to halt autophagy in gastric carcinoma

Circular RNAs (circRNAs) are covalently closed, endogenous molecules that are widespread in eukaryotes. Recent evidence indicates that circRNAs play important roles in carcinogenesis. Several circRNAs have been reported to comprise translatable RNA; however, whether circRNAs encode functional proteins remains unknown. In our study, circRNA sequencing was carried out using five pathologically diagnosed gastric carcinoma (GC) samples and their paired adjacent normal tissues, we characterized the circRNA GSPT1 (circGSPT1), which is expressed at low levels in GC. Antibody detections, and mass spectrometry were used to validate active circRNA translation. The spanning junction open reading frame in circGSPT1, driven by an internal ribosome entry site (IRES), encodes a functional peptide, termed GSPT1-238aa. Interestingly, GSPT1-238aa tends to select the start codon used to initiate translation. This is the first finding of selective translation driven by IRES. CircGSPT1 and GSPT1-238aa halted the proliferation, migration, and invasion in GC cells in vitro. We also confirmed that the vimentin/Beclin1/14-3-3 complex interacts with GSPT1-238aa and modulates autophagy via the PI3K/AKT/mTOR signaling pathway in GC cells. Our study reveals that GSPT1-238aa, a novel protein encoded by circGSPT1, halts GC tumorigenesis. We also provide insights into the function and underlying molecular mechanisms of GSPT1-238aa in GC and suggest that this protein represents a novel target for GC treatment.

MRNA microarray profiling identifies a novel circulating HTRA2 for detection of gastric cancer.

BackgroundmRNAs have been shown to be critical biomarkers or therapeutic targets for human diseases. However, only a few of them have been studied as blood‐based biomarkers for gastric carcinoma (GC) detection.MethodsmRNA expression profiles for GC were screened using plasma samples from 10 GC patients with different TNM stages and 5 healthy individuals as controls. One candidate tumor‐related mRNA named HTRA2 was then evaluated in GC samples with quantitative real‐time polymerase chain reaction (qRT‐PCR). TCGAportal, UALCAN, and TISCH database were used to explore the function of HTRA2 in GC. Finally, the effect generated by HTRA2 expression on cell proliferating, invading, and migrating processes was assessed in vitro with knockdown and over‐expression strategies.ResultsHTRA2 displayed noticeable increase inside GC plasma compared with control cases. Higher expression of HTRA2 displayed a correlation to higher clinicopathological stage and worse prognosis. HTRA2 knocking down down‐regulated GC cells' proliferating, invading, and migrating states, while HTRA2 over‐expression exerted the inconsistent influence. HTRA2 protein, which may interact with PINK1, PARL, and CYCS, was mainly located in the mitochondria of cells and primarily involved cellular response and metabolic signaling pathway. Immune factors may interact with HTRA2 in GC, and HTRA2 was found noticeably linked with immunosuppressor such as CD274, IDO1, and TIGIT.ConclusionOne plasma HTRA2 can be an emerging diagnosis‐related biomarker to achieve GC detecting process, but the particular regulatory effect still needs to be further explored.

Integrin \u03b21 orchestrates the abnormal cell-matrix attachment and invasive behaviour of E-cadherin dysfunctional cells

BackgroundTumour progression relies on the ability of cancer cells to penetrate and invade neighbouring tissues. E-cadherin loss is associated with increased cell invasion in gastric carcinoma, and germline mutations of the E-cadherin gene are causative of hereditary diffuse gastric cancer. Although E-cadherin dysfunction impacts cell–cell adhesion, cell dissemination also requires an imbalance of adhesion to the extracellular matrix (ECM).MethodsTo identify ECM components and receptors relevant for adhesion of E-cadherin dysfunctional cells, we implemented a novel ECM microarray platform coupled with molecular interaction networks. The functional role of putative candidates was determined by combining micropattern traction microscopy, protein modulation and in vivo approaches, as well as transcriptomic data of 262 gastric carcinoma samples, retrieved from the cancer genome atlas (TCGA).ResultsHere, we show that E-cadherin mutations induce an abnormal interplay of cells with specific components of the ECM, which encompasses increased traction forces and Integrin β1 activation. Integrin β1 synergizes with E-cadherin dysfunction, promoting cell scattering and invasion. The significance of the E-cadherin-Integrin β1 crosstalk was validated in Drosophila models and found to be consistent with evidence from human gastric carcinomas, where increased tumour grade and poor survival are associated with low E-cadherin and high Integrin β1 levels.ConclusionsIntegrin β1 is a key mediator of invasion in carcinomas with E-cadherin impairment and should be regarded as a biomarker of poor prognosis in gastric cancer.

Inhibition of MIR4435-2HG on Invasion, Migration, and EMT of Gastric Carcinoma Cells by Mediating MiR-138-5p/Sox4 Axis.

BackgroundThe previous investigations have identified that long non-coding RNA (lncRNAs) act as crucial regulators in gastric carcinoma. However, the function of lncRNA MIR4435-2HG in the modulation of gastric carcinoma remains elusive. Here, we aimed to explore the role of MIR4435-2HG in gastric carcinoma.MethodThe Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) were applied to select the differently expressed lncRNAs in gastric carcinoma. The qRT-PCR was applied to analyze MIR4435-2HG expression in carcinoma tissues and cell lines. The effect of MIR4435-2HG on proliferation, invasion, migration, and apoptosis of gastric carcinoma cells was detected by Cell Counting Kit-8 (CCK-8) assays, transwell assays, and flow cytometry in vitro. A subcutaneous tumor model was constructed to examine the tumor growth of gastric carcinoma cells after knocking out MIR4435-2HG. RNA immunoprecipitation and luciferase reporting assays were applied to evaluate the interaction of MIR4435-2HG, miR-138-5p, and Sox4.ResultsThe bioinformatics analysis based on TCGA and GEO databases indicated that MIR4435-2HG was obviously elevated in gastric carcinoma samples. The qRT-PCR analysis revealed that MIR4435-2HG was upregulated in clinical gastric carcinoma tissues and cells. The high expression of MIR4435-2HG is associated with the poor survival rate of patients. The knockout of MIR4435-2HG could repress the proliferation, invasion, migration, and epithelial–mesenchymal transition (EMT) and accelerate the apoptosis of gastric carcinoma cells. Moreover, the deletion of MIR4435-2HG was able to attenuate the tumor growth in vivo. Mechanically, we identified that MIR4435-2HG enhanced Sox4 expression by directly interacting with miR-138-5p as a competitive endogenous RNA (ceRNA) in gastric carcinoma cells, in which Sox4 was targeted by miR-138-5p.ConclusionMIR4435-2HG is elevated in gastric carcinoma cells and contributes to the growth, metastasis, and EMT of gastric carcinoma cells by targeting miR-138-5p/Sox4 axis. MIR4435-2HG may be applied as a potential therapeutic target in gastric carcinoma.

TRNA-Derived Fragment tRF-Glu-TTC-027 Regulates the Progression of Gastric Carcinoma via MAPK Signaling Pathway.

Transfer RNA-derived RNA fragments (tRFs) belong to non-coding RNAs (ncRNAs) discovered in most carcinomas. Although some articles have demonstrated the characteristics of tRFs in gastric carcinoma (GC), the underlying mechanisms still need to be elucidated. Meanwhile, it was reported that the MAPK pathway was momentous in GC progression. Thus we focused on investigating whether tRF-Glu-TTC-027 could act as a key role in the progression of GC with the regulation of the MAPK pathway. We collected the data of the tRNA-derived fragments expression profile from six paired clinical GC tissues and corresponding adjacent normal samples in this study. Then we screened tRF-Glu-TTC-027 for analysis by using RT-PCR. We transfected GC cell lines with tRF-Glu-TTC-027 mimics or mimics control. Then the proliferation, migration, and invasion assays were performed to assess the influence of tRF-Glu-TTC-027 on GC cell lines. Fluorescence in situ hybridization assay was conducted to confirm the cell distribution of tRF-Glu-TTC-027. We confirmed the mechanism that tRF-Glu-TTC-027 influenced the MAPK signaling pathway and observed a strong downregulation of tRF-Glu-TTC-027 in clinical GC samples. Overexpression of tRF-Glu-TTC-027 suppressed the malignant activities of GC in vitro and in vivo. MAPK signaling pathway was confirmed to be a target pathway of tRF-Glu-TTC-027 in GC by western blot. This is the first study to show that tRF-Glu-TTC-027 was a new tumor-suppressor and could be a potential object for molecular targeted therapy in GC.

EBV as a high infection risk factor promotes RASSF10 methylation and induces cell proliferation in EBV-associated gastric cancer

Epstein-Barr virus (EBV) is the first identified human tumor-related DNA virus, and has a high infection among people worldwide. Recent studies have showed that nearly 10% of gastric cancers have shown EBV infection and this kind of gastric cancer has been identified as a new subtype: EBV associated Gastric cancer (EBVaGC). Furthermore, it has been reported that tumor related genes in the EBVaGC showed frequent methylation modifications compared to those in the EBV negative gastric cancer (EBVnGC). To fully understand the role of EBV in EBVaGC, we analyzed and found that 16.67% of gastric carcinoma samples showed positive EBER1 signals. Mechanically, EBV-encoded Latent membrane protein 1 (LMP1) inhibited the expression of RASSF10, and promoted tumorigenesis by recruiting DNMT1 and inducing the DNA methylation of RASSF10. Altogether, it allows us a better understanding of the possible mechanism of EBV-induced gene hypermethylation in gastric cancer genome. Targeting EBV-induced DNA methylation is a potential therapeutic modality of EBVaGC.

Upregulation of microRNA-650 by PBX1 is correlated with the development of Helicobacter pylori-associated gastric carcinoma.

Helicobacter pylori (HP) infection induces the development of gastric carcinoma (GC), one of the most frequent and fatal cancers worldwide, via a progressive cascade. The roles of microRNAs (miRNAs) involved in the cascade and the behind mechanisms, however, are still unclear. This study was designed to investigate the expression of miR-650, a well-recognized oncogenic miRNA in GC samples and to analyze the associations between this miRNA and HP infection, and the molecular mechanism. Following miRNA- and mRNA-based microarray analyses, miR-650, pre-B-cell leukemia transcription factor 1 (PBX1), and LATS2 were filtered as targets. After that, function assays were implemented to assess their function in GC cells. miR-650 was upregulated in HP+ tissues and cells, and inhibition of miR-650 attenuated cell proliferation, invasion, migration, yet enhanced apoptosis. PBX1 was overexpressed in HP+ tissues and cells and promoted miR-650 transcription. Overexpression of PBX1 abrogated the effect of the miR-650 inhibitor on GC cells. miR-650 targeted LATS2, and LATS2 was poorly expressed in HP+ tissues and cell lines. Simultaneous knockdown of miR-650 and LATS2 reduced GC cell apoptosis. These results display that upregulation of miR-650 induced by HP infection and PBX1 dampens LATS2 in GC cells, potentially offering novel intervention targets for GC.

Identification of ALDH3A2 as a novel prognostic biomarker in gastric adenocarcinoma using integrated bioinformatics analysis

BackgroundExtensive research has revealed that genes play a pivotal role in tumor development and growth. However, the underlying involvement of gene expression in gastric carcinoma (GC) remains to be investigated further.MethodsIn this study, we identified overlapping differentially expressed genes (DEGs) by comparing tumor tissue with adjacent normal tissue using the Gene Expression Omnibus (GEO) and the Cancer Genome Atlas (TCGA) database.ResultsOur analysis identified 79 up-regulated and ten down-regulated genes. Functional enrichment analysis and prognosis analysis were conducted on the identified genes, and the fatty aldehyde dehydrogenase (FALDH) gene, ALDH3A2, was chosen for more detailed analysis. We performed Gene Set Enrichment Analysis (GSEA) and immunocorrelation analysis (infiltration, copy number alterations, and checkpoints) to elucidate the mechanisms of action of ALDH3A2 in depth. The immunohistochemical (IHC) result based on 140 paraffin-embedded human GC samples indicated that ALDH3A2 was over-expressed in low-grade GC cases and the OS of patients with low expression of ALDH3A2 was significantly shorter than those with high ALDH3A2 expression. In vitro results indicated that the expression of ALDH3A2 was negatively correlated with PDCD1, PDCD1LG2, and CTLA-4.ConclusionWe conclude that ALDH3A2 might be useful as a potential reference value for the relief and immunotherapy of GC, and also as an independent predictive marker for the prognosis of GC.

An immune-relevant signature of nine genes as a prognostic biomarker in patients with gastric carcinoma.

BackgroundAs one of the most common malignant tumors worldwide, the morbidity and mortality of gastric carcinoma (GC) are gradually increasing. The aim of this study was to construct a signature according to immune-relevant genes to predict the survival outcome of GC patients using The Cancer Genome Altas (TCGA).MethodsUnivariate Cox regression analysis was used to assess the relationship between immune-relevant genes regarding the prognosis of patients with GC. The least absolute shrinkage and selection operator (LASSO) Cox regression model was used to select prognostic immune-relevant genes and to establish the signature for the prognostic evaluation of patients with GC. Multivariate Cox regression analysis and Kaplan–Meier survival analysis were used to assess the independent prognostic ability of the immune-relevant gene signature.ResultsA total of 113 prognostic immune-relevant genes were identified using univariate Cox proportional hazards regression analysis. A signature of nine immune-relevant genes was constructed using the LASSO Cox regression. The GC samples were assigned to two groups (low- and high risk) according to the optimal cutoff value of the signature score. Compared with the patients in the high-risk group, patients in the low-risk group had a significantly better prognosis in the TCGA and GSE84437 cohorts (log-rank test P < 0.001). Multivariate Cox regression analysis demonstrated that the signature of nine immune-relevant genes might serve as an independent predictor of GC.ConclusionsOur results showed that the signature of nine immune-relevant genes may potentially serve as a prognostic prediction for patients with GC, which may contribute to the decision-making of personalized treatment for the patients.

High expression of ghrelin and obestatin prepropeptide in tumor tissues predicted adverse overall survival in gastric carcinoma patients.

Background:Gastric cancer (GC) is the most prevailing digestive tract malignant tumor worldwide with high mortality and recurrence rates. However, its potential molecular mechanism and prognostic biomarkers are still not fully understood. We aim to screen novel prognostic biomarkers related to GC prognosis using comprehensive bioinformatic tools.Methods:Four gene expression microarray data were downloaded from the Gene Expression Omnibus (GEO) database (GSE26942, GSE33335, GSE63089, and GSE79973). Differentially expressed genes (DEGs) between gastric carcinoma and normal gastric tissue samples were identified by an integrated bioinformatic analysis. Gene Ontology (GO) term enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were performed using statistical software R. STRING and Cytoscape software were employed to construct protein–protein interaction (PPI) networks. Hub genes with a high score of connectivity identified from the PPI network were identified. Prognostic values of hub genes were evaluated in GSE15459 dataset. Hub genes related to GC overall survival were further validated in GEPIA (Gene Expression Profiling Interactive Analysis) online tool.Results:A total of 12 upregulated DEGs and 59 downregulated DEGs were identified when the 4 microarray data overlapped. Among them, 10 hub genes with a high score of connectivity were identified. High expression of ghrelin and obestatin prepropeptide (GHRL), BGN, TIMP metallopeptidase inhibitor 1, thrombospondin 2, secreted phosphoprotein 1, and low expression of CHGA were associated with a poor overall survival of gastric cancer (all log rank P < .05). After validation in GEPIA database, only GHRL was confirmed associated with a poor overall survival of gastric cancer (log rank P = .04).Conclusions:GHRL could be used as a novel biomarker for the prediction of a poor overall survival of gastric cancer, and could be a novel therapeutic target for gastric cancer treatment. However, future experimental studies are still required to validate these findings.

EBV-miR-BART10-3p and EBV-miR-BART22 promote metastasis of EBV-associated gastric carcinoma by activating the canonical Wnt signaling pathway.

Epstein-Barr virus (EBV)-associated gastric carcinoma (EBVaGC) constitutes the largest subpopulation in EBV-associated tumors worldwide. To date, 44 mature EBV-encoded microRNAs (EBV miRNAs) have been identified, but their roles in EBVaGC development are still poorly understood. In this study, we aimed to investigate the roles and targets of ebv-miR-BART10-3p (BART10-3p) and ebv-miR-BART22 (BART22) in EBVaGC. EBV miRNA expression in EBVaGCs was evaluated by deep sequencing and qRT-PCR, and relationships between BART10-3p or BART22 expression and clinicolpathological characteristics and survival rates of patients with EBVaGC were analyzed. The roles of BART10-3p and BART22 and their underlying mechanisms were further investigated through exogenous overexpression or silencing in EBVaGC cells, and validated in clinical EBVaGC tissue samples. BART10-3p and BART22 were found to be highly expressed in the EBVaGC cell lines SNU719 and YCCEL1. Higher expression of BART10-3p or BART22 in primary EBVaGC samples was significantly associated with lymph node metastasis and a worse 5-year overall survival. BART10-3p and BART22 promoted cell migration and invasion by targeting adenomatous polyposis coli (APC) and Dickkopf 1 (DKK1), thereby activating the Wnt signaling pathway and, consequently, upregulating downstream Twist and downregulating downstream E-cadherin. In 874 primary gastric carcinoma samples, APC and DKK1 were found to be lower expressed in EBVaGC than in EBV-negative samples, and their expression levels were inversely correlated with those of BART10-3p and BART22 in 71 EBVaGC samples. From our data we conclude that BART10-3p and BART22 play vital roles in promoting EBVaGC metastasis by targeting APC and DKK1 and, subsequently, activating the Wnt signaling pathway, thereby providing novel prognostic biomarkers and potential therapeutic targets for EBVaGC.

Mining the role of RECQL5 in gastric cancer and seeking potential regulatory network by bioinformatics analysis

AimThe role of RecQ protein-like 5 (RECQL5) in gastric carcinoma (GC) is still unclear. Here, we investigated the role of RECQL5 in human GC and its potential regulatory network via bioinformatics analysis. MethodsBioinformatic analysis was performed using data in the Oncomine database, Kaplan- Meier Plotter online software, MethHC database, catalogue of somatic mutations in cancer (COSMIC), cbioportal database and String database. Then, we verified the association between RECQL5 expression and GC prognosis by immunohistochemistry (IHC). The independent prognostic factors were determined by Cox multivariate analysis. ResultsIt was found that both the mRNA and protein expression levels of RECQL5 were downregulated in GC samples (P < .05). Low RECQL5 expression indicated a poor prognosis in GC patients and is the independent prognostic factors for GC. No correlation between RECQL5 mRNA and DNA methylation was found using the MethHC database. The analysis of the COSMIC database showed a high proportion of missense mutation in GC. The functional enrichment analysis predicted that RECQL5 plays a role in DNA repair and cellular responses to DNA damage stimulus. RECQL5 might be enriched in homologous recombination pathways and Fanconi anemia pathway. Bioinformatics analysis identified 5 genes, namely POLR2D, POLR2G, DXO, KIN, and EIF2D, that were significantly correlated with RECQL5. ConclusionThe low expression of RECQL5 predicts poor overall survival in GC. RECQL5 may be a novel tumor suppressor for patients with GC.

NDRG1 suppresses vasculogenic mimicry and tumor aggressiveness in gastric carcinoma.

N-myc downstream regulated gene 1 (NDRG1) has been well characterized as a suppressor of metastasis in numerous types of carcinoma. NDRG1 inhibits the metastatic progression of cancer cells via its inhibitory effects on a wide variety of cellular signaling pathways. Vasculogenic mimicry (VM) refers to the unique ability of aggressive tumor cells to mimic the pattern of embryonic vasculogenic networks, and is the main reason for the poor prognosis and failure of antivascular therapy in gastric carcinoma (GC). Tumor cells can mimic the function of endothelial cells to exhibit VM through epithelial-mesenchymal transition (EMT). However, the potential function of NDRG1 in metastatic GC progression in patients has not yet been fully elucidated. To date, data regarding the function of NDRG1 in VM formation in GC have not been reported. The aim of the present study was to elucidate these unknown areas. To this end, 228 samples of human GC were used to identify the protein expression levels of NDRG1, VM-associated proteins and EMT-associated proteins via immunohistochemistry, and their clinical significance was assessed. In addition, the data of 415 patients with GC were collected from The Cancer Genome Atlas database. A functional enrichment analysis concerning NDRG1 was performed using Metascape and the Gene Set Enrichment Analysis (GSEA). In conclusion, the results of the present study indicate that NDRG1 is negatively correlated with poor prognosis through suppression of VM formation in GC. The results of the present study demonstrated that NDRG1 decreases EMT-associated protein expression and that HER2 expression may serve a significant role in this process. The Metascape and GSEA results also indirectly support this conclusion. The present study discusses the status NDRG1 as a prognostic and selective biomarker in GC, as well as current and future NDRG1-targeted therapies.

LncRNA ZEB2-AS1 contributes to the tumorigenesis of gastric cancer via activating the Wnt/β-catenin pathway.

Studies have shown that long noncoding RNA Zinc finger E-box-binding homeobox 2 antisense RNA 1 (ZEB2-AS1) is involved in the progression of lung cancer, bladder cancer, and hepatocellular carcinoma. However, its role in the pathogenesis of gastric cancer remains unknown. The Wnt/β-catenin pathway contributes to the development of gastric cancer. ZEB2-AS1 expression was firstly detected in the gastric carcinoma tissue samples as well as in gastric cancer cells. Knockdown of ZEB2-AS1 was performed by ZEB2-AS1-shRNA, and the viability, migration, invasion, and apoptosis of gastric cancer cells were determined by CCK-8, scratch assay, transwell, and flow cytometry, respectively. Furthermore, levels of Ki-67, PCNA, VEGF, MMP9, epithelial-mesenchymal transition (EMT) markers (E-cadherin, Vimentin and ZEB2), cleaved caspase 3/8/9 and PARP, active β-catenin, c-Myc, cyclinD1, and AXIN2 were assayed by Western blot or real-time PCR. Additionally, the role and mechanism of ZEB2-AS1 were confirmed in a xenograft nude mouse model. We found ZEB2-AS1 expression was increased in gastric carcinoma samples, and it was correlated with tumor progression. Also, its expression was elevated in gastric cancer cells. Knockdown of ZEB2-AS1 reduced the proliferation, migration, invasion, and EMT, but increased the apoptosis of gastric carcinoma cells. Furthermore, ZEB2-AS1 downregulation remarkably suppressed the expression of Ki-67, PCNA, VEGF and MMP9, and the activation of Wnt/β-catenin signaling, whereas elevated the levels of cleaved caspase 3/8/9 and PARP in gastric cancer cells. And ZEB2 overexpression reversed the effects of ZEB2-AS1 downregulation on the proliferation, EMT and inactivation of Wnt/β-catenin signaling. Additionally, ZEB2-AS1 knockdown inhibited tumor growth, Ki-67 staining, and the expression of VEGF, MMP9, active β-catenin, c-Myc, cyclinD1, and AXIN2 in mice. In conclusion, ZEB2-AS1 promotes the tumorigenesis of gastric carcinoma that is related to the upregulation of ZEB2 and the activation of the Wnt/β-catenin pathway.

Rituximab Treatment Prevents Lymphoma Onset in Gastric Cancer Patient-Derived Xenografts

Patient-Derived Xenografts (PDXs), entailing implantation of cancer specimens in immunocompromised mice, are emerging as a valuable translational model that could help validate biologically relevant targets and assist the clinical development of novel therapeutic strategies for gastric cancer.More than 30% of PDXs generated from gastric carcinoma samples developed human B-cell lymphomas instead of gastric cancer. These lymphomas were monoclonal, Epstein Barr Virus (EBV) positive, originated tumorigenic cell cultures and displayed a mutational burden and an expression profile distinct from gastric adenocarcinomas. The ability of grafted samples to develop lymphomas did not correlate with patient outcome, nor with the histotype, the lymphocyte infiltration level, or the EBV status of the original gastric tumor, impeding from foreseeing lymphoma onset. Interestingly, lymphoma development was significantly more frequent when primary rather than metastatic samples were grafted.Notably, the development of such lympho-proliferative disease could be prevented by a short rituximab treatment upon mice implant, without negatively affecting gastric carcinoma engraftment.Due to the high frequency of human lymphoma onset, our data show that a careful histologic analysis is mandatory when generating gastric cancer PDXs. Such care would avoid misleading results that could occur if testing of putative gastric cancer therapies is performed in lymphoma PDXs. We propose rituximab treatment of mice to prevent lymphoma development in PDX models, averting the loss of human-derived samples.