Expression Levels In Gastric Cancer Tissues Research Articles

Inhibition of gastric cancer cell apoptosis by long noncoding RNA TRPM2-AS via mitogen-activated protein kinase and activators of transduction-3.

Long noncoding RNA TRPM2-AS has emerged as a novel regulator in cancer initiation and progression of various cancers. However, the function and underlying mechanism of TRPM2-AS in the progression of gastric cancer (GC) remain poorly understood. GEO and TCGA databases were used for isolation of differential lncRNA expression. TRPM2-AS expression levels in GC tissues and cells were measured by quantitative polymerase chain reaction method. TRPM2-AS subcellular location was detected by fluorescence in situ hybridization analysis. The functional roles of TRPM2-AS in cells were analyzed by loss and gain function assays. By using bioinformatics and quantitative polymerase chain reaction methods, TRPM2-AS expression levels were proved to be upregulated in GSE70880 dataset, TCGA database, and 26 GC tissues, which was partly induced by SP1. The results of clinical assays showed that TRPM2-AS could be an indicator for early-stage GC diagnosis. Fluorescence in situ hybridization analysis showed that TRPM2-AS was located in both nucleus and cytoplasm. Functional experiments displayed that knockdown of TRPM2-AS inhibited proliferation, migration, and invasion in GC cells. Furthermore, depression of TRPM2-AS suppressed cell growth though promotion of cell apoptosis. The expression levels of cleaved PARP, caspase 9, caspase 3, and Bax were significantly increased in BGC823 with TRPM2-AS knockdown. In addition, knockdown of TRPM2-AS reduced and phosphorylate signal transducer and activator of transcription 3 and increased and phosphorylate p38 mitogen-activated protein kinase. This study demonstrated that SP1-regulated TRPM2-AS is involved in GC cell apoptosis probably via p38 mitogen-activated protein kinase and signal transducer and activator of transcription 3 pathways, indicating that TRPM2-AS might be a potential therapeutic target in GC.

Identification and Expression of Several Circular RNAs and Knockdown of hsa_circ_0005556 Exerts Oncogenic Functions by miR-767-5p in Gastric Cancer.

BackgroundGastric cancer (GC) remains one of the most fatal digestive cancers in the world; nevertheless, its etiology remains vague. With the development of bioinformatics analysis, numerous circular RNAs (circRNAs) have been found to be dysregulated in GC. However, the functions of a large portion of dysregulated circRNAs in GC need further validation. In this study, we aimed to validate the biological functions of circ_0005556, which was previously identified to be dysregulated in GC.Material/MethodsLevels of circRNAs and miRNAs in GC tissues and cells were estimated by qRT-PCR. The target miRNAs of circ_0005556 were predicted by bioinformatics methods. The interplay between circ_0005556 and miR-767-5p was validated by dual-luciferase reporter and circRNA immunoprecipitation assays. The effects of circ_0005556 and miR-767-5p on GC cell viability, apoptosis, migration, and invasion were assessed by MTT, flow cytometry, wound-healing and in vitro transwell experiments, respectively.ResultsThe upregulation of circ_0005556 was validated by qRT-PCR in GC tissues and cells, and a higher circ_0005556 level indicated a poorer prognosis. miR-767-5p was demonstrated to target circ_0005556 in GC cells, and a negative correlation was found between their expression levels in GC tissues. Knockdown of circ_0005556 promoted miR-767-5p expression in GC cells. Knockdown of circ_0005556 was revealed to repress GC cell viability, invasion, and migration and to promote GC cell apoptosis. Moreover, overexpression of miR-767-5p could significantly augment the repressive impacts of circ_0005556 knockdown on GC cell progression in vitro.ConclusionsThe in vitro knockdown of circ_0005556 remarkably repressed GC cell progression by increasing the expression of miR-767-5p.

Integrative Analysis of Differential lncRNA/mRNA Expression Profiling in Helicobacter pylori Infection-Associated Gastric Carcinogenesis.

Helicobacter pylori (H. pylori) infection is the greatest known risk factor for gastric cancer (GC). Long non-coding RNAs (lncRNAs) are implicated in multiple biological processes. However, their contribution in H. pylori-associated GC remains largely unknown. We performed transcriptome sequencing to investigate differential lncRNA and mRNA expression profiles in gastric AGS cells infected with the H. pylori strain 7.13 or 43504. We identified significantly differentially expressed (SDE) mRNAs and lncRNAs following H. pylori infection. A co-expression network of lncRNAs and mRNAs was constructed via WGCNA analysis. Moreover, several of the most significantly upregulated genes were selected for further validation by qRT-PCR analysis in H. pylori-infected gastric cells and transgenic INS-GAS mice. We finally evaluated these genes in human GC tissues. A total of 158442 genes were identified between uninfected and infected cells. Of these, 298 mRNAs and 73 lncRNAs were consistently differentially expressed following infection with the H. pylori 7.13 and 43504 strains, respectively. The expression levels of most upregulated mRNAs (DDIT4, NDRG1, CHAC1, IL32, RELB, CTH, and SLC7A1) and lncRNAs (lncRNA36068, lncRNA51663, lncRNA49853, lncRNA49852, and FLJ46906) were validated by qRT-PCR analysis. We found that H. pylori infection significantly induced the transcript levels of the coding genes RELB and SLC7A11 in in vitro and in vivo assays, which was supported by their high expression levels in GC tissues. In addition, lncRNA51663 and FLJ46906 were remarkably increased in H. pylori-infected cells and consistently overexpressed in human GC tissues compared to adjacent normal tissues. Our study identified mRNA and lncRNA expression profiles related to H. pylori infection. These results may provide important insights regarding lncRNAs in H. pylori-induced gastric carcinogenesis.

Identification of novel biomarkers, MUC5AC, MUC1, KRT7, GAPDH, CD44 for gastric cancer

Gastric cancer (GC) is one of the most common malignant tumors in the world, and it is also the third largest cause of cancer-related death in the world. As far as we know, no biomarker has been widely accepted for early diagnosis and prognosis prediction of gastric cancer. The purpose of this study is to find potential biomarkers to predict the prognosis of GC. The gene expression profiles of GSE2685 were downloaded from GEO database. Morpheus was used to calculate the differentially expressed genes (DEGs) between primary advanced gastric cancer tissues and noncancerous gastric tissues. The gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes pathway (KEGG) enrichment analyses were performed, and protein–protein interaction (PPI) network of DEGs was constructed. Kaplan–Meier Plotter was used to determine the overall survival (OS) outcomes of UC5AC, MUC1, KRT7, GAPDH, CD44, and GEPIA was used to determine the Pearson correlation analysis. In total, 710 DEGs were identified in GC, including 396 upregulated genes and 314 downregulated genes. GO enrichment revealed that they were mainly enriched in binding, catalytic activity, cellular process and cell. KEGG pathway revealed that they were mainly enriched in metabolic pathways, pathways in cancer and PI3K-Akt signaling pathway. MUC5AC, MUC1, KRT7, GAPDH, CD44 were identified from the PPI network. MUC5AC, MUC1, KRT7, GAPDH, CD44 were demonstrated to have prognostic value for patients with GC. MUC5AC, MUC1 exhibited low expression levels in GC tissues, KRT7, GAPDH, CD44 presented high expression levels in GC tissues. In particular, KRT7 is hardly expressed in normal gastric tissues. MUC5AC and MUC1 were negatively correlated with GAPDH, CD44, respectively; and GAPDH was positively correlated with CD44 and KRT7, respectively. Moreover. MUC5AC, MUC1, KRT7, GAPDH, and CD44 are not only related to GC but also to apoptosis pathway. Results from the present study suggested that MUC5AC, MUC1, KRT7, GAPDH, CD44 may represent novel prognostic biomarkers for GC.

Overexpression of long non-coding RNA RP11-363E7.4 inhibits proliferation and invasion in gastric cancer.

LncRNA RP11‐363E7.4 has been shown to be downregulated in gastric cancer (GC), while the effect of lncRNA RP11‐363E7.4 on GC and its potential molecular mechanisms is unclear. The purpose of this study was to explore the functional role and underlying molecular mechanisms of lncRNA RP11‐363E7.4 involved in GC progress.To address the question, quantitative real‐time PCR assay was performed to confirm lncRNA RP11‐363E7.4 expression levels in GC tissues and cell lines. Cell proliferation, apoptosis, migration and invasion were estimated using Cell Counting Kit‐8, colony formation, scratch wound healing and Transwell assays. Potential molecular mechanisms were evaluated using western blot assay. The results showed that lncRNA RP11‐363E7.4 was significantly downregulated in GC cell lines and 82 paired tissues. The correlation between expression and clinicopathological features indicated that low expression of lncRNA RP11‐363E7.4 was associated with T stage (P = .010). Functional experiments showed that overexpression of lncRNA RP11‐363E7.4 prevented proliferation, migration, and invasion and induced apoptosis of GC cells. Western blot assay revealed that lncRNA RP11‐363E7.4 functioned via the p53, Bax/Bcl‐2, β‐catenin pathway. In summary, this study revealed that lncRNA RP11‐363E7.4 functioned as a tumour suppressor by inhibiting proliferation, migration, and invasion and inducing apoptosis of GC cells. Significance of the study:LncRNA RP11‐363E7.4 has been shown to be downregulated in GC, while the effect of lncRNA RP11‐363E7.4 on GC and its potential molecular mechanism is unclear. We revealed that lncRNA RP11‐363E7.4 functioned as a tumour suppressor by inhibiting proliferation, migration, and invasion and inducing apoptosis of GC cells. LncRNA RP11‐363E7.4 might become an attractive diagnostic and prognostic biomarker of GC and a promising target for GC treatment.

Comprehensive Analysis of lncRNAs Associated with the Pathogenesis and Prognosis of Gastric Cancer.

Integrated analysis of accumulated data is an effective way to obtain reliable potential diagnostic molecular in gastric cancer (GC). The study aimed to identify potential lncRNAs associated with the pathogenesis and prognosis in GC. Raw noncoding RNA microarray data (GSE53137, GSE95667, and GSE111762) was downloaded from Gene Expression Omnibus (GEO) database. Differentially expressed genes between GC and adjacent normal gastric tissue samples were screened by an integrated analysis of multiple gene expression profile after gene reannotation and batch normalization. Differentially expressed genes were further confirmed by the cancer genome atlas (TCGA) database. Competing endogenous RNA (ceRNA) network, survival analysis, and gene set enrichment analysis (GSEA) were extensively applied to identify hub lncRNAs and discover potential biomarkers related to diagnosis and prognosis of GC. qPCR was applied to confirm hub lncRNA expression levels in GC tissues. In total, 17 integrated differential lncRNAs were obtained after intersections of differential genes between GEO and TCGA database. Four lncRNAs (HMGA1P4, UBE2Q1-AS1, MAGI2-AS3, MIR22HG) concentrated in ceRNA network were validated by qPCR in GC tissues, which were consistent with informatics results. The clinicopathological association revealed that four lncRNAs might be effective in GC progression. Further study revealed that GC patients with lower MAGI2-AS3 expression was evidently longer than those with higher MAGI2-AS3 expression (p = 0.015). Multivariate analysis revealed MAGI2-AS3 was independently associated with overall survival in GC. GSEA showed GC samples were differentially enriched in pyrimidine metabolism, RNA degradation, cell cycle, oxidative phosphorylation etc., and most significantly enriched in ribosome pathway in MAGI2-AS3 low expression phenotype. Four lncRNAs, including HMGA1P4, UBE2Q1-AS1, MAGI2-AS3, and MIR22HG may contribute to GC development, and MAGI2-AS3 might be associated with the prognosis of GC.

Hsa_circ_0065149 is an Indicator for Early Gastric Cancer Screening and Prognosis Prediction.

Circular RNAs (circRNAs) are an endogenous RNAs with a covalently closed cyclic structure. They have emerged recently as key regulators in the development and progression of human cancers. However, the clinical values of most circRNAs in gastric cancer (GC) are unknown. Hsa_circ_0065149, one of the dysregulated circRNAs in gastric carcinogenesis detected by circRNA microarray, was chose as a targeted circRNA in this study. We firstly enlarged sample size and identified the level changes of hsa_circ_0065149 among four stages of gastric tumorigenesis from healthy gastric mucosa, gastritis, intestinal metaplasia to GC. Then, the potential relationship between hsa_circ_0065149 expression levels and GC patients' clinicopathological factors was investigated. Moreover, the clinical significance of hsa_circ_0065149 in plasma exosomes and gastric juice were explored. Receiver operating characteristic (ROC) curve and Kaplan-Meier survival curve were constructed to evaluate diagnostic and prognostic values. Finally, bioinformatics analysis was performed to excavate the potential functions of hsa_circ_0065149. Hsa_circ_0065149 expression was only significantly down-regulated in gastric cancer, not changed among healthy gastric mucosa and gastritis intestinal metaplasia. Low hsa_circ_0065149 expression levels in GC tissues were significantly associated with tumor diameter (P= 0.034) and perineural invasion (P= 0.037). GC patients with low hsa_circ_0065149 levels had a much longer overall survival than those in high group (P= 0.020). More important, hsa_circ_0065149 levels were significantly decreased in plasma exosomes of early GC patients. As a screening biomarker for early GC, hsa_circ_0065149 in plasma exosomes has higher sensitivity and specificity than traditional clinical biomarkers. Bioinformatics analysis suggest that the abnormal expression of hsa_circ_0065149 may play an important role during gastric carcinogenesis. Those results indicate that hsa_circ_0065149 in exosmoes is an indicator for early GC screening and prognosis prediction.

Long noncoding RNA THAP9-AS1 is induced by Helicobacter pylori and promotes cell growth and migration of gastric cancer.

BackgroundLong noncoding RNAs (LncRNAs) have been confirmed to play crucial roles in cancer biology. Gastric cancer (GC) is the third leading cause of cancer related death, and Helicobacter pylori (H. pylori) is the major risk factor for GC. In this study, we focused on the roles of H. pylori-related lncRNAs in the progression of GC.MethodDifferentially expressed lncRNAs were identified through RNA-seq analysis of H. pylori-infected GC cells.ResultsWe found that the expression of the lncRNA THAP9-AS1 was up-regulated after infection of GC cells with H. pylori and was higher in GC tissues than in gastritis tissues. Colony formation, CCK8 and transwell assays were executed to show that THAP9-AS1 can promote GC cell proliferation and migration in vitro. Our study identified the pro-oncogenic lncRNA THAP9-AS1, which has a higher expression level in GC tissues than in gastritis tissues and which promoted the proliferation and migration of GC cells in vitro.ConclusionThese findings may provide a potential therapeutic target for H. pylori-associated GC.

HIT000218960 promotes gastric cancer cell proliferation and migration through upregulation of HMGA2 expression.

The aim of the present study was to elucidate whether the long non-coding RNA (lncRNA) HIT000218960 could accelerate the proliferative and migratory ability of gastric cancer (GC) cells by regulating high-mobility group AT-hook 2 (HMGA2) gene. The reverse transcription-quantitative polymerase chain reaction was used to determine HIT000218960 and HMGA2 expression levels in GC tissues and cells. The HMGA2 protein level was detected by western blotting. A χ2 test was used to determine the association between the HIT000218960 expression level and the clinical characteristics of patients with GC. GC cells were transfected with small interfering (si)-negative control, si-HIT000218960 and si-HIT000218960+pcDNA-HMGA2, prior to assessing the cell proliferative and migratory ability using the Cell Counting Kit-8 and Transwell assays, respectively. HIT000218960 and HMGA2 were highly expressed in GC tissues compared with in healthy tissues. In addition, HIT000218960 and HMGA2 were positively correlated in GC tissues. The HIT000218960 expression level was associated with tumor size, Tumor-Node-Metastasis staging and lymph node metastasis in patients with GC. HIT000218960 silencing decreased the proliferative and migratory ability of HGC27 and NCI-N87 cells; however, HMGA2 overexpression partly reversed this inhibitory effect. The results of the present study indicated that HIT000218960 could promote HGC27 and NCI-N87 cell proliferation and migration, which may be mediated by HMGA2.

Effect and mechanism of long noncoding RNAs HOTAIR on occurrence and development of gastric cancer.

In this study, we aimed at looking for the long noncoding RNA (lncRNA) abnormally expressed in gastric cancer (GC) tissues and analyzing the association of its expression level with the clinicopathological feature and patient prognosis. The biological function of this lncRNA in occurrence and development of GC was studied in vivo and in vitro. The underlying molecular mechanism was further discussed. We investigated the lncRNA expression level in GC tissues and normal gastric mucosa tissues by lncRNA chips analysis. The expression of lncRNA HOTAIR was detected by quantitative real time polymerase chain reaction (qRT-PCR). The relationship between HOTAIR expression level and prognosis was investigated by analyzing clinical samples. The influence of HOTAIR downregulation on GC cell proliferation, chemosensitivity, apoptosis, and invasion were determined by bromodeoxyuridine (BrdU) incorporation assay, flow cytometry analysis, and transwell assay. Tumor xenograft model was developed to study the influence of downregulated HOTAIR on tumor growth and metastasis. lncRNA HOTAIR had an extremely high expression level in GC cells, and predicted poor prognosis in patients. Downregulation of HOTAIR could promote chemosensitivity, induce apoptosis of GC cells, and significantly inhibit GC cell proliferation, invasion, and metastasis in vivo and in vitro. It was proved that HOTAIR played a positive role in GC occurrence and development according to the study in its mechanism, function, and clinical manifestation so that it could be expected to become a new target in GC prevention and treatment.

LINC00152 down-regulated miR-193a-3p to enhance MCL1 expression and promote gastric cancer cells proliferation.

The present work aimed to probe into the effect of long non-coding RNA (lncRNA) LINC00152 on gastric cancer (GC) cells proliferation by regulating miR-193a-3p and its target gene MCL1. Transfected si-LINC00152 was used to down-regulate LINC00152, and cells proliferation was measured by the cell counting kit-8 (CCK-8) assay. Cell apoptosis and cell cycle were analyzed by flow cytometry (FCM). Besides, we also detected the potential functional effects of differential expression of LINC00152 in vivo using nude mouse xenograft model. We overexpressed and downexpressed miR-193a-3p to study the in vitro effect of miR-193a-3p on GC cells proliferation and vitality. And MCL1 was silenced by shRNA to investigate the effect of MCL1 on proliferation of GC cells. In this research, LINC00152 was proven to have a higher expression level in GC tissues than in the adjacent normal tissues. GC cells proliferation was inhibited after LINC00152 was down-regulated. LINC00152 inhibited the expression of miR-193a-3p, which negatively regulated MCL1. In addition, GC cells proliferation was inhibited by cell transfection with shRNA-MCL1, and enhanced by transfection with miR-193a-3p mimics. Our study suggested that LINC00152 was overexpressed in GC tissues, and it down-regulated miR-193a-3p to enhance MCL1 expression thereby promoting GC cells proliferation.

Gene expression and prognosis of NOX family members in gastric cancer.

IntroductionNicotinamide adenine dinucleotide phosphate (NADPH) oxidases (NOX) are frequently deregulated in several human malignancies, including gastric cancer (GC). NOX-derived reactive oxygen species have been reported to contribute to gastric carcinogenesis and cancer progression. However, the expression and prognostic role of individual NOX in GC patients remain elusive.Methods and materialsWe investigated genetic alteration and mRNA expression of NOX family in GC patients via the cBioPortal, Human Protein Atlas, and Oncomine databases. Furthermore, we evaluated prognostic value of distinct NOX in GC patients through “The Kaplan–Meier plotter” database.ResultsOur analysis demonstrated that mRNA deregulation of NOX genes was common alteration in GC patients. Compared with normal tissues, NOX1/2/4 mRNA expression levels in GC tissues were higher, while NOX5 and DUOX1/2 expression levels were lower. Importantly, our results indicated that high mRNA expression of NOX2 was associated with better overall survival whereas NOX4 and DUOX1 were correlated with worse overall survival in all GC patients, particularly in intestinal-type GC patients. In addition, our data also shed light on the diverse roles of individual NOX members in GC patients with different clinicopathological features, including human epidermal growth factor receptor 2 status, clinical stages, pathological grades, and different choices of treatments of GC patients.ConclusionThese findings suggest that individual NOX family genes, especially NOX2/4, and DUOX1, are potential prognostic markers in GC and implicate that the use of NOX inhibitor targeting NOX4 and DUOX1 may be an effective strategy for GC therapy.

MiR-122-5p inhibits cell migration and invasion in gastric cancer by down-regulating DUSP4

ABSTRACTObjective: To explore the relationship between miR-122-5p and DUSP4 and their effects on gastric cancer (GC) cell mobility and invasiveness.Methods: Abnormally expressed miRNAs and mRNAs were analyzed using microarrays. The miR-122-5p and DUSP4 mRNA expression levels in GC tissues and cells were determined by RT-qPCR. The target relationship between miR-122-5p and DUSP4 was validated by dual luciferase reporter assay. GC cell mobility and invasiveness were respectively observed by wound healing assay and transwell invasion assay. Western blot and immunohistochemistry were used for detection of the expressions of DUSP4 protein and MMP2 and MMP9 proteins related to cell invasion and migration. The migration and invasion abilities of gastric cancer cells in vivo were evaluated according to the number of lung metastatic nodules in mice.Results: The expression of miR-122-5p in GC tissues and cells was significantly down-regulated, whereas DUSP4 expression was up-regulated. Bioinformatics prediction strategies and dual luciferase reporter assay verified the binding sites of miR-122-5p on 3′UTR of DUSP4 and the target relationship between miR-122-5p and DUSP4. Overexpression of miR-122-5p and knockdown of DUSP4 in BGC-823 cells observantly suppressed GC cell mobility and invasiveness, whereas downregulation of miR-122-5p expression promoted cell metastasis. MiR-122-5p inhibited GC cell mobility and invasiveness and pulmonary tumor metastasis via downregulation of DUSP4.Conclusion: MiR-122-5p restrained migration and invasion abilities of GC cells by repressing DUSP4.

Over-expression of oncigenic pesudogene DUXAP10 promotes cell proliferation and invasion by regulating LATS1 and \u03b2-catenin in gastric cancer

BackgroundRecently, the pesudogenes have emerged as critical regulators in human cancers tumorigenesis and progression, and been identified as a key revelation in post-genomic biology. However, the expression pattern, biological function and mechanisms responsible for these molecules in human gastric cancer (GC) are not fully understood.MethodsIn this study, we globally assessed the transcriptomic differences of pesudogenes in gastric cancer using publicly available microarray data. DUXAP10 expression levels in GC tissues and cells was detected using quantitative real-time PCR (qPCR). DUXAP10 siRNAs and over-expression vector were transfected into GC cells to down-regulate or up-regulate DUXAP10 expression. Loss- and gain-of function assays were performed to investigate the role of DUXAP10 in GC cells cell proliferation, and invasion. RIP, RNA pulldown, and ChIP assays were used to determine the mechanism of DUXAP10’s regulation of underlying targets.ResultsThe pesudogene DUXAP10 is the only pseudogene that significantly over-expressed in all four GEO datasets, and frequently over-expressed in many other cancers including Liver Hepatocellular carcinoma, Bladder cancer, and Esophageal Cancer. High DUXAP10 expression is associated with GC patients poor prognosis, and knockdown of DUXAP10 significantly inhibits cells proliferation, migration and invasion in GC. Mechanistic investigation shows that DUXAP10 can interact with PRC2 and LSD1 to repress LATS1 expression at transcriptional level, and bind with HuR to maintain the stability of β-catenin mRNA and increase its protein levels at post-transcriptional level.ConclusionsOverall, our findings illuminate how increased DUXAP10 confers an oncogenic function in GC development and progression that may serve as a candidate prognostic biomarker and target for clinical management of GC.

Long noncoding RNA‑ATB promotes cell proliferation, migration and invasion in gastric cancer.

Long noncoding RNA (lncRNA)‑activated by transforming growth factor (TGF)-β (lncRNA-ATB) was recognized as an unfavorable prognostic factor in various cancers; however, its regulatory role in gastric cancer (GC) remains elusive. The present study aimed to measure lncRNA‑ATB expression in GC and to explore its involvement in GC progression. lncRNA‑ATB expression levels were measured in 40pairs of GC tissues and their normal adjacent tissues, as well as in 5GC cell lines and a normal gastric mucosal cell line by reverse transcription-quantitative polymerase chain reaction. Knockdown experiments were performed to explore the effect of lncRNA‑ATB on the cell proliferation, invasion and migration. The results demonstrated that lncRNA‑ATB expression levels in GC tissues and GC cell lines were significantly higher than in the adjacent normal tissues and normal gastric mucosal cells. Further analysis of the correlation between the clinicopathological features and lncRNA‑ATB expression indicated that higher expression of lncRNA‑ATB was correlated with increased invasion depth, more distant metastasis and advanced tumor‑node‑metastasis stage. Inaddition, downregulated lncRNA‑ATB expression suppressed cellular proliferation, invasion and migration of GC cells. In conclusion, these data suggested that lncRNA‑ATB may serve as a clinical outcome predictor and potential therapeutic target in GC.

High TREM2 expression correlates with poor prognosis in gastric cancer

Triggering receptor expressed on myeloid cells 2 (TREM2) is a member of the immunoglobulin superfamily and associates with TYRO protein tyrosine kinase-binding protein at the cell membrane to form a receptor signaling complex. Gastric cancer (GC) is one of the most common human cancers in the world. We found that TREM2 expressions in GC and adjacent tissues were significantly different. The goal of this study was to measure TREM2 protein and mRNA expression levels in GC tissues and evaluate their value as potential prognostic markers. We analyzed TREM2 mRNA and protein expression by quantitative real-time polymerase chain reaction and immunohistochemistry, respectively, in 317 samples of GC tissue, matched normal tissue, or benign gastric lesions. The associations between TREM2 level and various clinicopathologic characteristics were assessed, and the correlation between TREM2 expression and prognosis of GC patients was analyzed using Oncomine and Kaplan-Meier Plotter online resources. TREM2 mRNA and protein expression levels were both significantly higher in GC compared with normal gastric tissues (P<.0001 and P<.001, respectively). Among the clinicopathological characteristics evaluated, differentiation (P<.05), N stage (P<.001), and TNM stage (P<.001) were all significantly associated with high TREM2 expression. TREM2 levels were inversely correlated with patient prognosis. Our data suggest that TREM2 expression could be an effective prognostic biomarker for GC.

MeCP2 regulated glycogenes contribute to proliferation and apoptosis of gastric cancer cells.

Aberrant glycogene and glycan expression is intimately associated with carcinogenesis, invasion, and metastasis of gastric cancer (GC); however the regulatory mechanisms for glycogenes in GC cells remain unclear. Methyl-CpG-binding protein 2 (MeCP2) regulates genes by binding to methylated promoters, and in our previous work we found that it is overexpressed in GC cell lines and tissues, functioning as an oncogene. In this study we detected the expression of 212 glycogenes in MeCP2 silenced GC cells versus control using the Agilent Whole Human Genome Microarray and mining the data through bioinformatic analysis. A total of 10 glycogenes exhibited increased expression (FC ≥ 2, P < 0.05), while 16 showed decreased expression (FC ≤ 2, P < 0.05) in the MeCP2 silenced cells, which corresponded to down-regulation of Lewis antigens (UEA-I), T/Tn antigens (PNA), and mature N-glycans (PHA-E and PHA-E+L) and up-regulation of lactosylceramide, a precursor oligosaccharide of N-glycans. Examination of the TCGA Gastric Cancer databases demonstrated that nine glycogenes (24.6%) were oppositely regulated by MeCP2 in MeCP2 knockdown BGC-823 cells relative to their expression level in GC tissues, and might be downstream genes of MeCP2. Individual gene analysis suggested that neutral alpha-glucosidase AB (GANAB) knockdown can rescue the effects of MeCP2 overexpression on GC cells. MeCP2 promotes GANAB by binding to the second methylated CpG island (206 bp, -12916 to -13122) of the GANAB promoter. In conclusion, glycogenes can be either up- or down-regulated by MeCP2 directly or indirectly to alter the glycopatterning and affect the proliferation and apoptosis of GC cells.

Low Expression of FBXO45 Is Associated with Gastric Cancer Progression and Poor Prognosis.

F-Box protein 45 (FBXO45) is reported to be associated with cancer aggressiveness. We investigated the relationship between FBXO45 and clinicopathological factors in gastric cancer (GC). We used immunohistochemistry to investigate FBXO45 expression in 104 GC samples; the prognostic value of FBXO45 was also calculated. FBXO45 levels in GC were higher than in normal tissues. Patients with relatively low FBXO45 expression (n=58) had increased cancer progression and poorer prognosis than those with high expression (n=46). Low FBXO45 expression was an independent negative prognostic factor in patients with GC. Using the public Kaplan-Meier plotter database, we showed that survival in patients with low expression of FBXO45 in GC was shorter than that in those with high FBXO45 expression, regardless of lymph node metastasis. A low FBXO45 expression level in GC tissues may be a powerful predictor of poor prognosis. FBXO45 might, therefore, be a promising candidate for a molecular targeted therapy in GC.

MAGI1 inhibits migration and invasion via blocking MAPK/ERK signaling pathway in gastric cancer.

ObjectiveTo explore the association of membrane-associated guanylate kinase inverted 1 (MAGI1) with gastric cancer (GC) and the related molecular mechanisms.MethodsThe reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry (IHC) were utilized to measure the MAGI1 expression level in GC tissues. Quantitative real-time PCR and Western blotting were used to ensure the MAGI1 expression in GC cell lines. Small hairpin RNA (shRNA) was applied for knockdown of endogenous MAGI1 in GC cells. MTT assay and colony formation assay, scratch wounding migration assay and transwell chamber migration assay, as well as transwell chamber invasion assay were employed respectively to investigate the GC cell proliferation, migration and invasion in MAGI1-knockdown and control GC cells. The potential molecular mechanism mediated by MAGI1 was studied using Western blotting and RT- PCR.ResultsRT-PCR and IHC verified MAGI1 was frequently expressed in matched adjacent noncancerous mucosa compared with GC tissues and the expression of MAGI1 was related to clinical pathological parameters. Functional assays indicated that MAGI1 knockdown significantly promoted GC cell migration and invasion. Further mechanism investigation demonstrated that one pathway of MAGI1 inhibiting migration and invasion was mainly by altering the expression of matrix metalloproteinases (MMPs) and epithelial-mesenchymal transition (EMT)-related molecules via inhibiting MAPK/ERK signaling pathway.ConclusionsMAGI1 was associated with GC clinical pathological parameters and acted as a tumor suppressor via inhibiting of MAPK/ERK signaling pathway in GC.

Evaluation of a novel functional single-nucleotide polymorphism (rs35010275 G>C) in MIR196A2 promoter region as a risk factor of gastric cancer in a Chinese population.

Single-nucleotide polymorphisms (SNPs) in microRNAs (miRNAs) have been suggested to influence the occurrence and progression of cancer through altering the expression and biological function of miRNAs. The aim of this study was to investigate whether the potential functional SNPs in MIR196A2 promoter had effect on the susceptibility to gastric cancer (GC) in a Chinese population.We conducted a 2-stage case-control study (753 cases and 854 controls in testing set; 940 cases and 1061 controls in validation set) to evaluate the association between 2 potential functional SNPs in MIR196A2 promoter (rs12304647 A>C and rs35010275 G>C) and GC risk. The luciferase reporter assay and electrophoretic mobility shift assay were used to examine the functionality of the important polymorphism.We found that the rs35010275 C allele was significantly associated with the decreased risk of GC (adjusted odds ratio = 0.85, 95% confidence interval = 0.77-0.94) in the combined case-control studies. The miR-196a expression levels in GC tissues were significantly higher than that in corresponding adjacent normal tissues (P < 0.001). Besides, each allele of rs35010275 displayed completely opposite effects to influence the transcription activity of MIR196A2 promoter via recruiting different transcription factors or complexes.The functional rs35010275 G>C polymorphism in MIR196A2 promoter was significantly associated with miR-196a expression and influenced the genetic susceptibility to GC.