Dual oncogenic roles of TPD52 and TPD52L2 in gastric cancer progression via PI3K/AKT activation and immunosuppressive microenvironment remodeling

Expression of MDM2 protein appears to be increased in malignancy and correlated to prognosis of tumors, but its role in gastric cancer remains controversial. Our recent investigations indicated that JWA was a novel candidate biomarker for gastric cancer. To evaluate the impact of MDM2 protein expression alone, and in combination with JWA, on the prognostic and predictive of patients with resectable gastric cancer, expression of MDM2 and JWA were examined by immunohistochemistry in three large cohorts (total n = 1131) of patient with gastric cancer. We found that MDM2 protein levels were significantly upregulated in gastric cancer (70.4%, 57 of 81) compared with adjacent non-cancerous tissues. High tumoral MDM2 expression significantly correlated with clinicopathologic characteristics, as well as with shorter overall survival (OS; P < 0.001 for all cohorts) in patients without adjuvant treatment. The effect of adjuvant fluorouracil-leucovorin-oxaliplatin (FLO) in improving OS compared with surgery alone was evident only in the high MDM2 group (hazard ratio = 0.57; 95% confidence interval, 0.37-0.89; P = 0.013). Furthermore, knockdown of MDM2 and overexpression of JWA had a synergistic effect on suppression of gastric cancer cell proliferation and migration. Patients with low MDM2 and high JWA expression had a better outcome of survival compared with the other groups (P < 0.001 for all cohorts). For the first time, our data suggest that MDM2 is a potent prognostic and predictive factor for benefit from adjuvant fluorouracil-leucovorin-oxaliplatin chemotherapy in resectable gastric cancer. The combination of MDM2 expression and JWA could serve as a more effective candidate prognostic biomarker for gastric cancer.

Background: Gastric cancer (GC) is a common and deadly cancer worldwide. Molecular changes underlying the development of GC are not thoroughly understood. Therefore, we constructed and analyzed a novel four-component competing endogenous RNA (ceRNA) network to introduce plausible diagnostic and prognostic biomarkers in GC. Materials and Methods: Transcriptomics and circular RNA (circRNA) data were retrieved from The Cancer Genome Atlas (TCGA) and the Gene Expression Omnibus (GEO) databases, respectively. After batch effect correction, differential expression analysis, and interaction prediction, a ceRNA network including long noncoding RNAs (lncRNAs), circular RNAs (circRNAs), microRNAs (miRNAs), and messenger RNAs (mRNAs) was established. Enrichment analyses were performed, and a protein–protein interaction (PPI) network was constructed. Furthermore, a subnetwork was extracted, and using the quantitative real-time polymerase chain reaction (qRT-PCR) method, the expression changes of two hub ceRNAs were examined. Finally, survival analysis was performed to identify potential prognostic RNAs. Results: A four-component ceRNA network containing 822 nodes and 1365 edges was constructed. Enrichment analyses unveiled important signaling pathways and gene ontologies such as neuroactive ligand–receptor interaction and axonogenesis. The PPI network showed the interactions among mRNAs of the ceRNA network. qRT-PCR indicated downregulation of EPHA5 and SNAP91 mRNAs in GC compared to control tissues. Survival analyses revealed eight mRNAs and one lncRNA as potential prognostic biomarkers in GC. Conclusion: The established four-component network of ceRNAs in GC reveals a comprehensive view of the molecular and cellular characteristics of GC progression, which can be considered as a basis to examine and validate potential diagnostic and prognostic biomarkers as well as therapeutic targets.

Lactate metabolism plays a vital role in tumor progression. Currently, gastric cancer (GC) has a poor prognosis. Therefore, our research aimed to investigate novel biomarkers related to lactate metabolism in patients. Patient data from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) database were divided into subtypes based on the expression of lactate metabolism-related genes (LMRGs). Based on the subtypes, we identified coiled-coil domain containing 80 (CCDC80) for further investigation. Univariate and multivariate Cox regression models were constructed to determine the prognostic value of CCDC80 in GC. We further explored the mechanism by which CCDC80 affects GC prognosis using gene set enrichment analysis (GSEA). Immune infiltration and drug sensitivity analyses were also performed. Finally, immunohistochemical staining was used to evaluate CCDC80 expression in normal and tumor tissues. We observed that CCDC80 was overexpressed in GC samples and was significantly associated with T and pathological stages. Multivariate Cox analysis identified high CCDC80 expression as an independent prognostic marker. GSEA indicated that the oxidative phosphorylation pathway was highly enriched in the low CCDC80 expression group. Moreover, CCDC80 was associated with immune cell infiltration, especially that of M2 macrophages. Patients with higher CCDC80 expression exhibited lower sensitivity to paclitaxel. In conclusion, our findings demonstrate that CCDC80 is a critical regulator in GC progression and immune response and is associated with lactate metabolism, and it could be used as a novel biomarker for prognostic and chemotherapy treatment purposes.

We report that the odd-skipped related 1 (OSR1) gene encoding a zinc-finger transcription factor was preferentially methylated in gastric cancer by genome-wide methylation screening. OSR1 expression was frequently silenced or down-regulated in gastric cancer cell lines. OSR1 expression was also significantly down-regulated at both mRNA and protein levels in primary gastric cancer tissues compared with adjacent normal tissues. The silencing or down-regulation of OSR1 was closely associated with promoter hypermethylation. Overexpression of OSR1 significantly inhibited cell growth, arrested the cell cycle, and induced apoptosis in the gastric cancer cell lines AGS, MKN28, and MGC803. Conversely, knockdown of OSR1 by OSR1-short hairpin RNA significantly enhanced cell growth, promoted the cell cycle, and inhibited apoptosis in the normal gastric epithelial cell line GES1. The dual-luciferase reporter assay revealed that OSR1 activated p53 transcription and repressed the T-cell factor (TCF)/lymphoid enhancer factor (LEF). Complementary DNA expression array and western blotting showed that OSR1 increased the expression of nuclear p53, p21, Fas, and death receptor-5, and suppressed the expression of cyclin D1 and cyclin-dependent kinase 4 in the p53 signalling pathway. In addition, OSR1 suppressed the expression of cytoplasmic β-catenin, TCF-1, and LEF1 in the Wnt/β-catenin signalling pathway. OSR1 methylation was detected in 51.8% of primary gastric cancer patients (85 of 164) by bisulphite genomic sequencing. Multivariate Cox regression analysis showed that OSR1 methylation was an independent predictor of poor survival. Kaplan–Meier survival curves revealed that OSR1 methylation was associated with shortened survival in TNM stage I–III patients. In conclusion, OSR1 acts as a functional tumour suppressor through the transcriptional activation of p53 and repression of TCF/LEF in gastric cancer. Detection of OSR1 methylation may serve as a potential biomarker of the early stage of gastric cancer. © 2014 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

Gastric cancer (GC) has a very poor prognosis as most cases are diagnosed at a late stage, which can be partially attributed to a lack of reliable diagnostic biomarkers. Our study reveals a close correlation between monocyte to macrophage differentiation-associated (MMD) and GC. We analyzed data from The Cancer Genome Atlas (TCGA). A close association between MMD levels and the clinicopathological features of gastric cancer patients was identified using Cox regression analysis and KM plot database analysis. Bioinformatics data were validated by real-time polymerase chain reaction and western blot analysis in GC cells. The impact of MMD on GC was examined using multiple complementary assays, including colony formation assay, CCK-8 assay, cell cycle analysis, apoptosis assessment, wound healing assay, transwell assay, and subcutaneous xenograft tumor formation assay in mice. High levels of MMD were observed in GC tissues. MMD accelerated cell growth and metastasis, and suppressed apoptosis in GC cells. MMD inhibition significantly suppressed the growth of xenograft tumors in mice. Further studies had revealed that MMD expression was suppressed by miR-200b-3p in GC. Dual luciferase experiment indicated that MMD is a direct target gene of miR-200b-3p. MMD might play an oncogenic role in GC by acting as a direct target of miR-200b-3p. MMD plays an oncogenic role in gastric cancer. It may serve as a potential biomarker for GC diagnosis and a therapeutic target.

As one of the most prevalent gastrointestinal diseases, gastric cancer (GC) is the second leading cause of cancer-related deaths worldwide. Since GC has no clinical manifestations in the early stage of the disease, most patients are detected in the later phases of disease and have an unfortunately lower chance of recovery. Circular RNAs (circRNAs), a novel category of non-coding RNAs (ncRNAs), are mainly engaged in the regulation of gene expression at the transcriptional and post-transcriptional levels. Numerous evidences have revealed that circRNAs play key roles in GC as they are involved in cell proliferation, growth, and apoptosis via modulating the expression of some target genes, miRNAs, and proteins. Many studies have addressed the impact of circRNA dysregulation on GC initiation, progression, and invasion via binding to miRNAs or RNA binding proteins. Moreover, changes in circRNA expression are associated with pathological and clinical features of GC highlighting their potentials as diagnostic or prognostic biomarkers in GC. In the current study, the recent findings on the significance of circRNAs in the development and progression of GC are reviewed. We focus on the implications of circRNAs as potential diagnostic or prognostic biomarkers in this malignancy.

Increased expression of S100A6 in many cancer tissues and its association with tumor behavior and patient prognosis were demonstrated, and there are no studies analyzing the serum levels of S100A6 in patients with gastric cancer (GC). Serum S100A6 levels were investigated as a marker of tumor aggressiveness in patients with GC, and the S100A6 gene was examined as a potential therapeutic target in GC. Serum S100A6 levels were detected in 103 GC patients and 72 healthy subjects by ELISA. Clinicopathological features of GC patients were analyzed in correlation to serum S100A6 levels. Two small interfering RNAs against S100A6 (siRNA1-S100A6 and siRNA2-S100A6) were generated and transfected into SGC7901 cells using pSUPER gfp-neo vector, and the effects of S100A6 knockdown on cell proliferation, invasion and apoptosis were evaluated in vitro. The effects of S100A6 silencing on tumor growth and metastasis were evaluated in vivo in a pseudo-metastatic GC nude mouse model. Serum S100A6 levels were significantly higher in GC patients than in healthy controls (P < 0.001). Serum S100A6 levels were significantly correlated with lymph node metastasis, TNM stage, perineural invasion and vascular invasion. Serum S100A6 level was an independent predictor of overall survival. SiRNA-mediated silencing of S100A6 significantly induced apoptosis and decreased proliferation, clone formation and the invasiveness of GC SGC7901 cells in vitro and significantly reduced tumor volume and number in vivo (P < 0.01). Serum S100A6 level may serve as a potential prognostic biomarker in GC. Inhibition of S100A6 decreased the metastatic potential of GC cells.

BackgroundThere have been few available prognostic biomarkers in gastric cancer. We rigorously assessed the clinical relevance of promoter DNA methylation of Cysteine dioxygenase type 1 (CDO1) gene, a cancer-specific aberration, in human gastric cancer.MethodsQuantitative CDO1 methylation value (TaqMeth V) was initially calculated in 138 gastric cancer patients operated in 2005, and its clinical significance was elucidated. As a subsequent expanded set, 154 gastric cancer patients with pathological stage (pStage) II / III with no postoperative therapy were validated between 2000 and 2010.Results(1) Median TaqMeth V of CDO1 gene methylation of gastric cancer was 25.6, ranging from 0 to 120.9. As pStage progressed, CDO1 TaqMeth V became higher (p < 0.0001). (2) The optimal cut-off value was determined to be 32.6; gastric cancer patients with high CDO1 gene methylation showed a significantly worse prognosis than those with low CDO1 gene methylation (p < 0.0001). (3) A multivariate cox proportional hazards model identified high CDO1 gene methylation (p = 0.033) as an independent prognostic factor. (4) The results were recapitulated in the expanded set in pStage III, where high CDO1 gene methylation group had a significantly worse prognosis than low CDO1 gene methylation group (p = 0.0065). Hematogenous metastasis was unique in pStage III with high CDO1 gene methylation (p = 0.0075). (5) Anchorage independent growth was reduced in several gastric cancer cell lines due to forced expression of the CDO1 gene, suggesting that abnormal CDO1 gene expression may represent distant metastatic ability.ConclusionsPromoter DNA hypermethylation of CDO1 gene was rigorously validated as an important prognostic biomarker in primary gastric cancer with specific stage.

Background: This study aimed to confirm the role of enhancer RNAs (eRNAs) in gastric cancer and their clinical utility. Methods: We used Cox survival and relevance analysis to identify the candidate eRNAs in gastric cancer and performed Gene Ontology and Reactome pathway enrichment to determine the potential functions of eRNAs. Correlation between eRNA, tumor-infiltrating immune cells, and drug sensitivity was then analyzed. Results: CDK6-AS1, a long non-coding RNA cyclin-dependent kinase 6, may serve as a poor potential prognostic biomarker candidate in gastric cancer with a positive correlation with its target gene CDK6. The low CDK6-AS1 expression group showed more frequent mutated driver genes than the high expression group. Moreover, CDK6-AS1 is involved in a key oncogenic pathway of the cell cycle and RNA transcription. CDK6-AS1 also shows dysregulations and associations with prognosis at the pan-cancer level. This eRNA may also be associated with immune cell infiltration and drug sensitivity. Conclusion: CDK6-AS1 may be a potential prognostic biomarker and chemotherapeutic drug sensitivity predictor in gastric cancer.

Cartilage oligomeric matrix protein (COMP) is a protein that has been implicated in the development of some tumors, but its exact role in gastric cancer (GC) remains unclear. The study aims to comprehensively examine COMP in GC and to confirm its effects through experimental methods. The research harnessed data from the Cancer Genome Atlas (TCGA) to explore the significance of COMP in GC and its potential as a diagnostic tool. The study also examined the regulatory networks involving COMP, including its interactions with immune cells, immune checkpoint genes, tumor mutational burden (TMB), microsatellite instability (MSI), and the stemness index based on mRNA expression (mRNAsi). Additionally, the study explored the relationship between COMP expression and drug sensitivity in GC. Genomic variations of COMP in GC were assessed. The expression of COMP was validated by the GEPIA2 tool and confirmed with quantitative reverse transcription PCR (qRT-PCR) in cell lines (normal human gastric epithelial cells GES-1 and GC cell lines AGS and HGC-27). Abnormal expression patterns of COMP were observed in various cancers, including GC. Higher levels of COMP in GC were significantly associated with the pathologic T stage and a history of reflux (p < 0.05 for both). Elevated COMP expression was correlated with poorer progression-free survival (PFS) (p = 0.027). COMP expression levels were identified as an independent prognostic factor for GC (p = 0.017). COMP was linked to TCF-dependent signaling in response to ECM receptor interaction, focal adhesion, and other pathways. There was an association between COMP expression and immune infiltration, immune checkpoint genes, TMB/MSI, and mRNAsi in GC. COMP expression was inversely correlated with the sensitivity to several drugs, indicating that higher levels of COMP may reduce the effectiveness of these drugs. COMP was found to be significantly up-regulated in GC cell lines. COMP could serve as a prognostic biomarker and a potential therapeutic target for the treatment of GC.

Gastric cancer (GC) is a common tumors in the digestive tract, and effective treatment methods are still lacking. Bone morphogenetic protein 6 (BMP6) is closely related to the occurrence and development of various tumors, but its relevance to GC is still unclear. The aim of the study was to explore the relationship between BMP6 and the occurrence and development of GC. In this study, we investigated the relationship between BMP6 and the prognosis of GC patients using bioinformatics technology and clinical tissue samples. We also explored the connection between BMP6 and the biological behavior of GC cells through molecular biology experiments and relevant in vivo animal experiments. Finally, we examined the mechanisms by which BMP6 inhibits the onset and progression of GC. Through analysis of The Cancer Genomics Atlas (TCGA) database, we observed that BMP6 is expressed at low levels in GC, and its low expression is associated with a poor prognosis in GC patients. Cell experiments demonstrated that BMP6 expression can influence the proliferation of GC cells both in vitro and in vivo. Furthermore, we discovered that BMP6 is linked to the nuclear factor-κB (NF-κB) pathway, and subsequent experiments confirmed that BMP6 can inhibit the biological activity of GC cells by activating the NF-κB pathway. Our findings suggest that BMP6 is a potential prognostic biomarker in GC and can regulate the biological activity of GC cells through the NF-κB pathway. BMP6 may serve as a promising therapeutic target for GC, and our study introduces novel ideas for the prevention and treatment of this disease.

Objective: This study aimed to identify the hub gene in gastric cancer (GC) tumorigenesis. A biomarker prediction model was constructed and analyzed, and protein expression in histopathological samples was verified in a validation cohort. Methods: Differentially expressed genes (DEGs) were identified from GC projects in The Cancer Genome Atlas (TCGA) database. Functional enrichment analysis of DEGs was performed between the high- and low- Ribonuclease P protein subunit p30 (RPP30) expression groups. ROC analysis was performed to assess RPP30 expression to discriminate GC from normal tissues. Functional enrichment pathways and immune infiltration of DEGs were analyzed using GSEA and ssGSEA. Survival analysis and nomogram construction were performed to predict patient survival. Immunohistochemical staining of GC tissues was performed to validate RPP30 expression in GC and paracancerous samples. Results: Gene expression data and clinical information of 380 cases (375 GC samples and 32 para-cancerous tissues) were collected from TCGA database. The AUC for RPP30 expression was found to be 0.785. The G alpha S signaling pathway was the most significantly enriched signaling pathway. Primary therapy outcome (p < 0.001, HR = 0.243, 95% CI = 0.156–0.379), age (p = 0.012, HR = 1.748, 95% CI = 1.133–2.698), and RPP30 expression (p < 0.001, HR = 2.069, 95% CI = 1.346–3.181) were identified as independent prognostic factors. As a quantitative approach, a nomogram constructed based on RPP30 expression, age, and primary therapy outcome performed well in predicting patient survival. Nineteen of the 25 tissue samples from the validation cohort showed positive RPP30 expression in GC tissues, whereas 16 cases showed negative RPP30 staining in normal tissues. The difference between the two was statistically significant. Conclusion: High RPP30 expression was significantly correlated with disease progression and poor survival in GC, promoting tumorigenesis and angiogenesis via tRNA dysregulation. This study provides new and promising insights into the molecular pathogenesis of tRNA in GC.

Gastric cancer (GC) is one of the most common malignancies in the world and ranks third in terms of cancer-related deaths. The catalytically inactive pseudophosphatase STYX (serine/threonine/tyrosine interacting protein) is a member of the protein tyrosine phosphatase family. It has been recently reported that STYX functions as a potential oncogene in different types of cancers. However, the potential role and regulatory mechanism of STYX in GC remains unknown. In this study, we find that STYX is highly expressed in GC tissues compared with adjacent noncancerous tissues and closely correlates with the prognosis of GC patients. STYX overexpression facilitates the proliferation and migration in GC cells, whereas STYX knockdown has the opposite effects. Nude mice experiments indicate that STYX knockdown in GC cells dramatically suppresses the tumor growth and lung metastasis in vivo. Mechanically, our results suggest that STYX interacts with the F-box protein FBXO31 and disrupts the degradation function of FBXO31 to its target proteins CyclinD1 and Snail1, thereby increasing the level of CyclinD1 and Snail1 in GC. STYX-mediated biological changes can be reversed by the co-expression of STYX and FBXO31 in GC cells. In addition, transcription factor c-Jun can enhance the expression of STYX in GC. The expression of STYX can also be induced by Helicobacter pylori (H. pylori) infection in c-Jun-dependent manner. Together, our present study suggests that STYX plays an oncogenic role in GC by inhibiting FBXO31 function and represents a potential therapeutic target and prognostic biomarker in GC.

Long noncoding RNAs are involved in several kinds of cancers. Here, we reported that ANRIL (CDKN2B-AS1), a 3.8-kb long noncoding RNA, recruiting and binding to PRC2, was generally upregulated in human gastric cancer (GC) tissues. In a cohort of 120 GC patients, the higher expression of ANRIL was significantly correlated with higher TNM stages (P = 0.041) and larger tumor sizes (P = 0.001). Multivariate analyses revealed that ANRIL expression served as an independent predictor for overall survival (OS) (P = 0.036). Further experiments revealed that the knockdown of ANRIL significantly repressed the proliferation of GC cell lines both in vitro and in vivo. We also showed that E2F1 could induce ANRIL and ANRIL-mediated growth promotion is partly due to epigenetic repression of miR-99a/miR-449a in Trans (controlling the targets_mTOR and CDK6/E2F1 pathway) by binding to PRC2, thus forming a positive feedback loop, continuing to promote GC cell proliferation. To our knowledge, this is the first report which showed that the role of ANRIL in the progression of GC and ANRIL could crosstalk with microRNAs in epigenetic level. Our results suggest that ANRIL, as a growth regulator, may serve as a potential prognostic biomarker and target for new therapies in human GC. Citation Format: Zhi Xu, Jinfei Chen, John M. Luk, Wei De. LncRNA ANRIL indicates a potential prognostic biomarker in gastric cancer and promotes tumor growth by silencing of miR-99a/miR-449a. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 157. doi:10.1158/1538-7445.AM2015-157

BackgroundThe goal of this study is to evaluate the effectiveness of S-1/Oxaliplatin vs. Doxifluridine/Oxaliplatin regimen and to identify miRNAs as potential prognostic biomarkers in gastric cancer patients. The expression of candidate miRNAs was quantified from fifty-five late stage gastric cancer FFPE specimens.Experimental DesignGastric cancer patients with KPS>70 were recruited for the trial. The control group was treated with 400 mg/twice/day Doxifluridine plus i.v. with Oxaliplatin at 130 mg/m2/first day/4 week cycle. The testing group was treated with S-1 at 40 mg/twice/day/4 week cycle plus i.v. with Oxaliplatin at 130 mg/m2/first day/4 week cycle. Total RNAs were extracted from normal and gastric tumor specimens. The levels of miRNAs were quantified using real time qRT-PCR expression analysis.ResultsThe overall objective response rate (CR+PR) of patients treated with S-1/Oxaliplatin was 33.3% (CR+PR) vs. 17.6% (CR+PR) with Doxifluridine/Oxaliplatin for advanced stage gastric cancer patients. The average overall survival for patients treated with S-1/Oxaliplatin was 7.80 month vs. 7.30 month with patients treated with Doxifluridine/Oxaliplatin. The expression of miR-181b (P = 0.022) and miR-21 (P = 0.0029) was significantly overexpressed in gastric tumors compared to normal gastric tissues. Kaplan-Meier survival analysis revealed that low levels of miR-21 expression (Log rank test, hazard ratio: 0.17, CI = 0.06–0.45; P = 0.0004) and miR-181b (Log rank test, hazard ratio: 0.37, CI = 0.16–0.87; P = 0.018) are closely associated with better patient's overall survival for both S-1 and Doxifluridine based regimens.ConclusionPatients treated with S-1/Oxaliplatin had a better response than those treated with Doxifluridine/Oxaliplatin. miR-21 and miR-181b hold great potential as prognostic biomarkers in late stage gastric cancer.