Clinical Outcomes Of Gastric Cancer Patients Research Articles

Cytolytic activity score as a biomarker for antitumor immunity and clinical outcome in patients with gastric cancer.

BackgroundA simple measure of immune cytolytic activity (CYT) base on mRNA expression levels of two genes, GZMA and PRF1, was recently reported. Here, we aimed to evaluate the CYT score's potential as a measure of antitumor immunity and predictor of clinical outcome in gastric cancer (GC) patients.Materials and MethodsWe evaluated the correlations between tumor‐infiltrating immune cells and the CYT score in 238 GC samples from The Cancer Genome Atlas (TCGA). Next, we investigated CYT score associations with molecular subtypes, somatic mutation load, and immune checkpoint molecules in GC samples from TCGA and Asian Cancer Research Group (ACRG). Moreover, we evaluated the clinical significance of the CYT score calculated by reverse transcription (RT)‐quantitative PCR (qPCR) data in 123 GC samples and the association of the CYT score with the response to anti‐PD‐1 therapy in 7 GC samples from Kyushu University Hospital.ResultsThe CYT score positively correlated with the proportions of tumor‐infiltrating CD8+ T cells and macrophages and negatively correlated with the proportion of regulatory T cells in GC tissues. A high CYT score was associated with common immune checkpoint molecules, a high mutation, the Epstein–Barr virus subtype, and the microsatellite instability subtype in GC. Moreover, a low CYT score was a poor prognosis factor in patients with GC. Finally, the CYT score was higher in a responder to anti‐PD‐1 therapy compared to nonresponders.ConclusionThe CYT score reflects antitumor immunity and predicts clinical outcome in GC patients.

NUSAP1 Promotes Gastric Cancer Tumorigenesis and Progression by Stabilizing the YAP1 Protein.

The Yes-associated protein (YAP1) is a main effector of the canonical Hippo pathway, which contributes greatly to tumor initiation, progression, and metastasis in multiple cancers, including gastric cancer (GC). Due to limited knowledge of YAP1 upregulation in cancer, it is a great challenge of therapeutic targets toward the Hippo–YAP1 pathway. Here, we identify nucleolar spindle-associated protein 1 (NUSAP1) as a novel binding partner of YAP1. The upregulation of NUSAP1 is associated with unfavorable clinical outcomes in GC patients, and NUSAP1 depletion impairs its oncogenic properties in vitro and in a xenograft model. Mechanistically, we discovered that NUSAP1 functions as a positive regulator of YAP1 protein stability, thereby inducing the transcription of Hippo pathway downstream target genes, such as CTGF and CYR61. More interestingly, we find that the cancer-promoting effects of NUSAP1 on GC cell growth, migration, and invasion are mainly mediated by YAP1. Furthermore, aberrant expression of NUSAP1 and YAP1 is highly correlated in GC cell lines and tissues. We herein clarify the role of the oncogenic NUSAP1–YAP1 axis in GC tumorigenesis and progression and, therefore, provide novel therapeutic targets for GC treatment.

Bioinformatics-based analysis of the association between the A1-chimaerin (CHN1) gene and gastric cancer

ABSTRACT Gastric cancer (GC) is one of the most common causes of cancer-related deaths worldwide and the identification of additional therapeutic targets and biomarkers has become vital. The A1-chimaerin (CHN1) gene encodes a ras-related protein that can be activated or inactivated by binding to GTP or GDP. The present study aimed to assess the expression of CHN1 in GC tissue and cells, to explore its relationship with GC progression, and to discover the potential mechanisms underlying these associations. The ONCOMINE database and The Cancer Genome Atlas (TCGA) were used to determine the transcriptional levels of CHN1 in GC. Western blot and immunohistochemistry were used for detecting protein expression. Correlations between CHN1 levels and the clinical outcomes of GC patients were examined using Kaplan–Meier and Cox regression analyses. Moreover, the CIBERSORT algorithm was used to estimate immune cell infiltration. In GC patients, CHN1 transcription and CHN1 protein expression were upregulated, and a high expression of CHN1 was remarkably linked to poor survival in GC patients. CHN1 expression was associated with immune infiltrates and this gene showed potential involvement in multiple cancer-related pathways. Furthermore, the expression of CHN1 was correlated with the immunotherapeutic response. Finally, our results indicated that the pro-carcinogenic role of CHN1 may involve DNA methylation. To our knowledge, this is the first report characterizing CHN1 expression in GC. Our results show that high CHN1 levels could be used as a clinical biomarker for poor prognosis and that CHN1 inhibitors may have potential as anti-cancer drugs.

LncRNA MYLK-AS1 acts as an oncogene by epigenetically silencing large tumor suppressor 2 (LATS2) in gastric cancer

ABSTRACT Extensive studies showed the vital function of long noncoding RNAs (lncRNAs) in the pathological and physiological progression of tumors. Previous evidence has indicated that lncRNA MYLK Antisense RNA 1 (MYLK-AS1) acts as an oncogene to facilitate the progression of several tumors. Nevertheless, little is known about its biological role in gastric cancer (GC). Our report intended to probe the underlying mechanism and function of MYLK-AS1 in GC. Results revealed that MYLK-AS1 showed an upregulated level in GC. It was worth mentioning that upregulated MYLK-AS1 caused the unfavorable clinical outcome in GC patients. Functional assays indicated that MYLK-AS1 silencing retarded the proliferation, cell cycle, migration, and invasion in GC. Besides, in vivo assay validated that MYLK-AS1 deficiency also restrained tumor growth. Through in-depth mechanism exploration, MYLK-AS1 was uncovered to bind with wnhancer of zeste homolog 2 (EZH2), an epigenetic inhibitor, to inhibit the level of Large Tumor Suppressor 2 (LATS2), thereby exerting carcinogenicity. Conclusively, our research highlighted the importance of MYLK-AS1 in GC, indicating that MYLK-AS1 might be an effective biomarker for GC.

High Centromere Protein-A (CENP-A) Expression Correlates with Progression and Prognosis in Gastric Cancer.

PurposeRecent studies have established the ability of centromere protein-A (CENP-A) to perform as an oncogene, regulating tumor progression. The aim of this research was to explore the relationship between CENP-A expression and clinical significance in gastric cancer (GC) patients.Materials and MethodsExperiments with a microarray were conducted using the Affymetrix U133 plus 2.0 GeneChip Array. Upregulated differentially expressed genes (DEGs) were identified via the GEO2R and intersected using a Venn diagram. Bioinformatic databases Omcomine, GEPIA, and Ualcan were applied to investigate the expression level of CENP-A in GC. The real-time quantitative RT-PCR (qRT-PCR) was used to validate the level of CENP-A mRNA in GC. Immunohistochemistry (IHC) was employed to verify the protein levels of CENP-A, while the relationship between CENP-A expression and patients’ clinical parameters in GC was explored through the use of IHC. Kaplan-Meier analysis was conducted to evaluate the prognostic significance of CENP-A. Additionally, the Kaplan-Meier plotter database (KM plotter) was used to verify the prognostic function of CENP-A in GC patients.ResultsThe results indicated that CENP-A was significantly overexpressed, both in protein and mRNA levels of GC tissues, compared to adjacent noncancerous tissues (P<0.05). Furthermore, we observed that CENP-A expression was positively associated with TNM stage, tumor classification, lymph node metastasis, distant metastasis, and Lauren type (P<0.05). Kaplan-Meier analysis showed that patients with an overexpression of CENP-A had significantly poorer overall survival (OS) times (P<0.05). Multivariate analysis suggested CENP-A may serve as an independent predicting factor for the poor outcome of GC patients.ConclusionOur results show that CENP-A upregulation is significantly correlated with advanced tumor progression and poor prognosis. CENP-A may function as a novel potential biomarker for predicting the clinical outcomes of GC patients.

AMIGO2 Expression as a Potential Prognostic Biomarker for Gastric Cancer.

Although our understanding of the molecular mechanisms of gastric cancer (GC) development and progression is steadily deepening, the clinical outcome of GC patients remains inadequate. The identification of molecules associated with GC will help improve prognosis. We aimed to identify the molecules involved in GC progression and metastasis. Transcriptome analysis was performed on surgically resected gastric tissue from patients with hepatic metastasis. Fourteen cell lines and 230 pairs of primary GC tissues and their corresponding normal adjacent tissues were included in the mRNA expression analysis. Adhesion molecule with Ig like domain 2 (AMIGO2) was identified as a gene of interest. The levels of AMIGO2 mRNA positively correlated with those encoding FOXC2, NODAL, GEMIN2 and negatively correlated with TFPI2. Patients with high AMIGO2 expression experienced significantly shorter disease-free survival and overall survival. High levels of AMIGO2 were associated with poor prognosis. Patients with GC with high AMIGO2 mRNA levels experienced significantly shorter survival, suggesting that AMIGO2 may serve as a prognostic biomarker for GC.

Value of Plasma Methylated SFRP2 in Prognosis of Gastric Cancer.

Secreted frizzled-related protein 2 (SFRP2) in circulating tumor DNA (ctDNA) is related to gastric cancer (GC) proliferation. However, whether methylated SFRP2 in ctDNA serves as the biomarker in GC patients remains unknown. To investigate the relationship between methylated SFRP2 and the clinical outcomes of GC patients. One hundred and forty-eight GC patients receiving systemic chemotherapy were collected during 2015-2017. Aberrant SFRP2 methylation was detected before and after chemotherapy by digital PCR-based technologies. Baseline SFRP2 methylation positively correlated with lymph node status (P < 0.001), distant metastasis (P < 0.001) and TNM stage (P = 0.005). The top 50% methylated SFRP2 had shorter progression-free survival (PFS) and overall survival (OS) than those with bottom 50% in stage III GC patients (median PFS, 11.0 vs. NR months; HR 13.05; 95% CI 3.05-55.95; median OS 17.0 vs. NR months; HR 7.80; 95% CI 1.81-33.60) and stage IV GC patients (median PFS, 4.0 vs. 7.0months; HR 2.74; 95% CI 1.58-4.78; median OS 12.0 vs. 16.0months; HR 3.14; 95% CI 1.67-5.92). Besides, the increased methylated SFPR2 from baseline to post-treatment was related to the worse PFS and OS among stage IV patients (median PFS, 5.0 vs. 7.0months; HR 2.17; 95% CI 1.25-3.76; median OS 12.0 vs. 15.5months; HR 3.51; 95% CI 1.94-6.35), but not to stage III patients. SFRP2 methylation and dynamic change are associated with GC prognosis. Our findings provide potential biomarker detection approach in ctDNA for prognosis prediction and dynamic monitoring among GC patients.

Prognostic Values of Radiosensitivity Genes and CD19 Status in Gastric Cancer: A Retrospective Study Using TCGA Database.

BackgroundThe correlation between the radiosensitivity genes combined with CD19 status and clinical outcome was investigated to identify gastric cancer (GC) patients who would benefit from radiotherapy combined with CAR-T cell therapy.MethodsThe gene expression and clinical features were downloaded from The Cancer Genome Atlas (TCGA) Stomach Cancer (STAD). To identify the hub radiosensitivity genes and CD19 status, 407 patients were categorized into two groups: radiosensitivity (RS) and radioresistance (RR) based on the prognosis. The chi-square test, Mann–Whitney test, and Kaplan–Meier survival analysis were applied to compare the differential expression in these groups and analyze the correlation between the gene expression and clinical outcome and features. Finally, the influencing factors for the prognosis of GC were investigated by multiple Cox regression, especially in RS patients.ResultsA total of 15 differential expression genes, containing two communities with 8 hub radiosensitivity genes, were identified. We also identified a 2-gene signature model with a negative coefficient and calculated the risk score for the prognosis of GC. Also, Helicobacter pylori infection was validated, and the high-risk score of radiosensitivity genes was the risk factor, and high CD19 expression was the protective factor for the prognosis.ConclusionThe radiosensitivity gene signature and CD19 expression predicted the clinical outcome of GC patients.

AMOTL1 enhances YAP1 stability and promotes YAP1-driven gastric oncogenesis

Hippo signaling functions to limit cellular growth, but the aberrant nuclear accumulation of its downstream YAP1 leads to carcinogenesis. YAP1/TEAD complex activates the oncogenic downstream transcription, such as CTGF and c-Myc. How YAP1 is protected in the cytoplasm from ubiquitin-mediated degradation remains elusive. In this study, a member of Angiomotin (Motin) family, AMOTL1 (Angiomotin Like 1), was screened out as the only one to promote YAP1 nuclear accumulation by several clinical cohorts, which was further confirmed by the cellular functional assays. The interaction between YAP1 and AMOTL1 was suggested by co-immunoprecipitation and immunofluorescent staining. The clinical significance of the AMOTL1–YAP1–CTGF axis in gastric cancer (GC) was analyzed by multiple clinical cohorts. Moreover, the therapeutic effect of targeting the oncogenic axis was appraised by drug-sensitivity tests and xenograft-formation assays. The upregulation of AMOTL1 is associated with unfavorable clinical outcomes of GC, and knocking down AMOTL1 impairs its oncogenic properties. The cytoplasmic interaction between AMOTL1 and YAP1 protects each other from ubiquitin-mediated degradation. AMOTL1 promotes YAP1 translocation into the nuclei to activate the downstream expression, such as CTGF. Knocking down AMOTL1, YAP1, and CTGF enhances the therapeutic efficacies of the first-line anticancer drugs. Taken together, AMOTL1 plays an oncogenic role in gastric carcinogenesis through interacting with YAP1 and promoting its nuclear accumulation. A combination of AMOTL1, YAP1, and CTGF expression might serve as a surrogate of Hippo activation status. The co-activation of the AMOTL1/YAP1–CTGF axis is associated with poor clinical outcomes of GC patients, and targeting this oncogenic axis may enhance the chemotherapeutic effects.

Low expression of lncRNA MGC27345 is associated with poor prognosis in gastric cancer patients.

A series of evidence showed that long non-coding RNAs (lncRNAs) play an essential regulatory role in the occurrence and development of human cancer, and is a potential biological target in the fight against cancer. In this research, we investigated the role of lncRNA MGC27345 in gastric cancer (GC), the expression of MGC27345 in GC was detected by quantitative Real-Time PCR in GC tissue from 235 patients. The correlations between MGC27345 expression and clinicopathological variables and survival were evaluated by the Chi-square test. Kaplan-Meier method (log-rank test), univariate and multivariate Cox regression assays were carried out for the identification of the survival and independent risk factors for GC. MGC27345 expression levels were significantly decreased in GC tissues than in adjacent normal specimens. Lower expression of MGC27345 was found in advanced tumor stages. GC patients with low-expression of MGC27345 had a poorer overall survival compare to those with high-expression of MGC27345. Furthermore, MGC27345 was an independent protective prognosis factor in GC development. Our data indicated that MGC27345 may have a diagnostic and prognostic value for patients with advanced gastric cancer and assist to improve clinical outcomes for GC patients.

Genetic polymorphisms in folate-metabolizing genes associated with gastric cancer prognosis in northwest China subjects.

Influence of folate metabolism has long been studied in cancer and copies evidences have suggested that the key genes involved were correlated with GC risk and prognosis. However, their genetically association and contribution for GC prognosis are still elusive. To evaluate the effect of folate metabolism related genes polymorphisms on the prognosis of gastric cancer (GC), the genotype of seven single nucleotide polymorphisms (SNPs) of three genes were selected and genotyped in a cohort of 664 GC patients, including genes of Methylenetetrahydrofolate reductase (MTHFR), Methionine synthase reductase (MTRR), and Methionine synthase (MTR). Kaplan-Meier Curve, long-rank tests and multivariate Cox proportional hazard model were used for prognosis analysis. The results demonstrated that TT or CT/TT genotypes of SNP rs1532268 in MTRR gene coding region are significantly associated with a poorer overall survival (OS) when compared with CC genotype (HR=2.340, 95% CI: 1.240-4.414, p=0.009; or HR=1.502, 95% CI: 1.083-2.085, p=0.015, respectively). Furthermore, comparing to that of the CC genotype, the detrimental effect of rs1532268 TT genotype was also evident in the special subgroups of GC patients, especially in patients with BMI<24 and H. pylori infection. Moreover, significant association between increased relapse and TT genotype of rs1532268 was also observed in patients who are females, BMI<24 and without chemotherapy. In addition, the joint analysis demonstrated that integration of rs1532268 genotypes and BMI, H. pylori infection status, clinical stage and tumor site may significantly improve the predictive abilities for predicting OS of GC patients. In conclusion, it suggested that the MTRR rs1532268 polymorphism is significantly associated with clinical outcomes of GC patients, especially in those with lower BMI (BMI<24) or positive H. pylori infection status, which warrants further validation. And the polymorphism of MTRR rs1532268 may be a potential prognostic factor for GC patients.

Long noncoding RNA VCAN‐AS1 contributes to the progression of gastric cancer via regulating p53 expression

Gastric cancer (GC) is one of the most frequent malignancies worldwide. Long noncoding RNAs (lncRNAs) are found to be largely implicated in various cancers, including GC. However, the function of lncRNA VCAN antisense RNA 1 (VCAN-AS1) in GC remains unclear. Herein, we observed a low level of VCAN-AS1 in normal gastric tissues through NCBI and UCSC, and that VCAN-AS1 upregulation in GC tissues was related to poor prognosis by TCGA. Furthermore, VCAN-AS1 was found markedly enhanced in GC tissues and cell lines, while its upregulation was related with clinical outcomes of GC patients. Besides this, silencing VCAN-AS1 represses cell proliferation, migration, and invasion but enhances apoptosis. More important, we discovered that VCAN-AS1 expression was negatively correlated with wild-type p53 levels in GC tissues and that p53 was negatively modulated by VCAN-AS1 in GC cells. Furthermore, p53 suppression reversed the repression of VCAN-AS1 silence on the biological processes of AGS cells. Intriguingly, we identified that both VCAN-AS1 and TP53 can bind with eIF4A3, one of the core proteins in the exon junction complex. Also, we confirmed that VCAN-AS1 negatively regulates TP53 expression by competitively binding with eIF4A3. Our findings disclosed that VCAN-AS1 contributes to GC progression through interacting with eIF4A3 to downregulate TP53 expression, indicating that VCAN-AS1 is a novel therapeutic strategy for GC treatment.

Abstract 3146: MFG-E8: A novel prognostic marker for gastric cancer

Abstract Gastric cancer is one of the leading causes of cancer-related death all over the world. Milk fat globule-epidermal growth factor (EGF)-factor VIII (MFG-E8) was found to be highly unregulated in a variety of cancers, could induce phagocytosis of apoptotic cells and a significant factor in immune systems. However, its prognostic potential has not been evaluated in gastric cancer (GC). In our former proteomic study, MFG-E8 was found significantly overexpressed in gastric cancer tissues comparing with paired non-cancerous gastric tissues. This study aimed to analyze the association between the expression of MFG-E8 in GC tissues and clinical outcomes in GC patients. In this study, 3 independent cohorts (GSE15460, n = 192; TCGA, n = 380 and ACRG, n = 300) were used to assess MFG-E8 as a biomarker, Kaplan-Meier survival analysis showed that its overexpression was associated with poor prognosis of GC with good discriminative ability in 3 independent cohorts (GSE15460, P &amp;lt;0.001; TCGA, P &amp;lt;0.001 and ACRG, P &amp;lt;0.001). Multivariate analysis further confirmed its prognostic significance (GSE15460, P =0.028; TCGA, P &amp;lt;0.001 and ACRG, P =0.012). These results suggest MFG-E8 may become a potential prognostic factor for GC. Note: This abstract was not presented at the meeting. Citation Format: Sai Ge, Jing Gao, Lin Shen. MFG-E8: A novel prognostic marker for gastric cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3146.

The novel lncRNA p4516 acts as a prognostic biomarker promoting gastric cancer cell proliferation and metastasis.

Purpose: Emerging evidence has shown that long noncoding RNAs (lncRNAs) participate in oncogenesis and tumor progression. We previously found a novel lncRNA p4516 which was closely associated with prognosis by preliminary study of lncRNA expression profile from paired tumors and nontumor tissues in 198 gastric cancer (GC) patients. However, the exact biological functions and the underlying molecular mechanisms of p4516 in gastric tumorigenesis still remain unclear.Materials and methods: The RNA fluorescence in situ hybridization (RNA-FISH) analysis, cytoplasmic and nuclear RNA isolation and qRT-PCR were applied to determine the subcellular localization of p4516. Expression levels of p4516 were assessed using qRT-PCR in both GC cell lines and in 142 primary GC tissues. Correlations between p4516 expression and GC patients’ clinicopathological parameters were analyzed. Gain- and loss-of-function experiments were employed to investigate the role of p4516 in proliferation, migration and invasion both in vitro and in vivo. In addition, Western blotting and immunohistochemical staining were used to examine the protein expression levels.Results: LncRNA p4516 was mainly localized in the nucleus of GC cells and p4516 tended to have higher expression levels in GC cells compared to the normal gastric mucosa-derived cells GES-1. Furthermore, higher expression levels of p4516 correlated with worse clinical outcomes in GC patients and acted as an independent prognostic biomarker. Functional analysis revealed that p4516 participated in the regulation of GC cell proliferation, invasion and migration both in vivo and in vitro. Moreover, p4516 was involved in epithelial–mesenchymal transition (EMT) in GC cells.Conclusion: Our study demonstrated the oncogenic role of novel lncRNA p4516 in the gastric carcinogenesis for the first time. High expression of p4516 may act as prognostic marker in patient with gastric cancer.

Triglyceride-to-high density lipoprotein cholesterol ratio predicts clinical outcomes in patients with gastric cancer.

Correlation of triglyceride (TG)-to-high density lipoprotein cholesterol (HDL-C) ratio (TG/HDL-C) and the survival of gastric cancer (GC) remain unclear. The purpose of this study was to explore the precise effect of preoperative TG/HDL-C on clinical outcomes in GC patients. Patients with GC were enrolled from 2006 to 2014. A total of 957 individuals from a single center were divided into prospective training and retrospective test cohorts. The optimal cutoff value of TG/HDL-C was determined using X-tile software to separate the training cohort into low and high survival groups according to TG/HDL-C levels. Survival analyses were performed using Kaplan-Meier curves and a Cox proportional hazards regression model. Preoperative TG/HDL-C and clinical outcomes were obtained to determine the prognostic significance of serum lipids in the training and test cohorts. We observed that high TG and TG/HDL-C were significantly correlated with poor outcome in GC patients, and high TG/HDL-C harbored the highest area under curve to independently predict 5-year overall survival in two cohorts. Furthermore, c-index of the prognostic nomogram including TG/HDL-C was significantly higher than that without it. In summary, TG/HDL-C was an efficient and independent prognostic factor to predict 5-year case fatality of GC patients and to improve the efficacy of its prognostic nomogram.

Plasmacytoid Dendritic Cells and ICOS+ Regulatory T Cells Predict Poor Prognosis in Gastric Cancer: A Pilot Study

Background: Regulatory T cells (Tregs) and plasmacytoid dendritic cells (pDCs) are the main immunosuppressive cells in tumor microenvironment of gastric cancer (GC). In this prospective study, the association of prognosis with Tregs subsets and pDCs were further analyzed.Methods: pDCs, Tregs population and its expression of inducible costimulator (ICOS) were analyzed in peripheral blood from 41 GC patients by multicolor flow cytometry. These cell populations in carcinoma tissue, peritumor tissue and normal gastric mucosa from 87 GC patients were also detected by immunohistochemistry and double immunofluorescence.Results: Both ICOS+Foxp3+Treg cells (P=0.0341 and P=0.0298, respectively) and pDC (P=0.0237 and P=0.0083, respectively) in peripheral blood and tumor tissue could predict poor clinical outcome in GC patients. However, the total Foxp3+Tregs in the GC tissue didn't correlated with the outcome (P=0.4299). No correlation of CD4+ T cell or CD8+ T cell frequency could be found with clinical outcome neither in peripheral blood nor in tumor tissue.Conclusions: ICOS+Tregs and pDCs could predict poor prognosis of GC, targeting ICOS-L/ICOS costimulation axis may be a potential treatment for GC.

Stromal fibroblast activation protein alpha promotes gastric cancer progression via epithelial-mesenchymal transition through Wnt/ \u03b2-catenin pathway

BackgroundTo investigate the influence of fibroblast activation protein alpha (FAP) derived from cancer-associated fibroblasts (CAFs), as well as potential mechanism of epithelial mesenchymal transition (EMT), on gastric cancer (GC) progression.MethodsCorrelation between CAFs-derived FAP and clinical results has been studied by using 60 GC cases. To confirm this relationship, SGC7901 cells were co-cultured with pre-established FAP-overexpressed fibroblasts in vitro and the characteristics including proliferation, migration, invasion and apoptosis abilities were detected subsequently. Meanwhile, SGC and GES1 cells cocultured with FAP-overexpressed fibroblasts were treated with cis-platinum for apoptotic analysis. The underlying EMT was detected by analyzing expression level of E-cadherin, ZO-1, N-cadherin, Vimentin, α-SMA, DKK1 and LEF-1 through western blot and immunofluorescence staining assay. Finally, the tumor-promoting ability of FAP was investigated by utlizing a xenograft gastric cancer nude mouse model.ResultsIt show that FAP has a high-risk correlation with the malignant level of clinical outcomes in GC patients. FAP promotes the ability of proliferation, migration, invasion, apoptosis-inhibition of SGC7901 cells and induces apoptosis of GES1 cells in vitro. The mechanism study shows that epithelial markers have been down-regulated and mesenchymal markers and Wnt/β-catenin signal pathway related proteins have been up-regulated. Animal assay suggests that tumor burden has been enhanced by FAP significantly in vivo.ConclusionsStromal FAP could be a potential prognostic biomarker in GC by promoting cancer progression via EMT through Wnt/ β-catenin signal pathway.

ECD promotes gastric cancer metastasis by blocking E3 ligase ZFP91-mediated hnRNP F ubiquitination and degradation

The human ortholog of the Drosophila ecdysoneless gene (ECD) is required for embryonic development and cell-cycle progression; however, its role in cancer progression and metastasis remains unclear. Here, we found that ECD is frequently overexpressed in gastric cancer (GC), especially in metastatic GC, and is correlated with poor clinical outcomes in GC patients. Silencing ECD inhibited GC migration and invasion in vitro and metastasis in vivo, while ECD overexpression promoted GC migration and invasion. ECD promoted GC invasion and metastasis by protecting hnRNP F from ubiquitination and degradation. We identified ZFP91 as the E3 ubiquitin ligase that is responsible for hnRNP F ubiquitination at Lys 185 and proteasomal degradation. ECD competitively bound to hnRNP F via the N-terminal STG1 domain (13-383aa), preventing hnRNP F from interacting with ZFP91, thus preventing ZFP91-mediated hnRNP F ubiquitination and proteasomal degradation. Collectively, our findings indicate that ECD promotes cancer invasion and metastasis by preventing E3 ligase ZFP91-mediated hnRNP F ubiquitination and degradation, suggesting that ECD may be a marker for poor prognosis and a potential therapeutic target for GC patients.

Expression of the Hippo transducer TAZ in association with WNT pathway mutations impacts survival outcomes in advanced gastric cancer patients treated with first-line chemotherapy

BackgroundAn extensive crosstalk co-regulates the Hippo and Wnt pathway. Preclinical studies revealed that the Hippo transducers YAP/TAZ mediate a number of oncogenic functions in gastric cancer (GC). Moreover, comprehensive characterization of GC demonstrated that the Wnt pathway is targeted by oncogenic mutations. On this ground, we hypothesized that YAP/TAZ- and Wnt-related biomarkers may predict clinical outcomes in GC patients treated with chemotherapy.MethodsIn the present study, we included 86 patients with advanced GC treated with first-line chemotherapy in prospective phase II trials or in routine clinical practice. Tissue samples were immunostained to evaluate the expression of YAP/TAZ. Mutational status of key Wnt pathway genes (CTNNB1, APC and FBXW7) was assessed by targeted DNA next-generation sequencing (NGS). Survival curves were estimated and compared by the Kaplan–Meier product-limit method and the log-rank test, respectively. Variables potentially affecting progression-free survival (PFS) were verified in univariate Cox proportional hazard models. The final multivariate Cox models were obtained with variables testing significant at the univariate analysis, and by adjusting for all plausible predictors of the outcome of interest (PFS).ResultsWe observed a significant association between TAZ expression and Wnt mutations (Chi-squared p = 0.008). Combined TAZ expression and Wnt mutations (TAZpos/WNTmut) was more frequently observed in patients with the shortest progression-free survival (negative outliers) (Fisher p = 0.021). Uni-and multivariate Cox regression analyses revealed that patients whose tumors harbored the TAZpos/WNTmut signature had an increased risk of disease progression (univariate Cox: HR 2.27, 95% CI 1.27–4.05, p = 0.006; multivariate Cox: HR 2.73, 95% CI 1.41–5.29, p = 0.003). Finally, the TAZpos/WNTmut signature negatively impacted overall survival.ConclusionsCollectively, our findings indicate that the oncogenic YAP/TAZ–Wnt crosstalk may be active in GC, conferring chemoresistant traits that translate into adverse survival outcomes.

Abstract 4720: Novel findings for the clinical significance of RNA editing status of AZIN1 and ADAR 1 and 2 expression levels in gastric cancer patients

Abstract Background. Despite recent advances in surgical techniques and treatment options, gastric cancer (GC) remains the third most common cause of cancer-related deaths worldwide. Besides DNA sequence mutations, epigenetic alterations have emerged as significantly major players in cancer development. A-to-I RNA editing is a post-transcriptional modification that converts adenosines to inosines in both coding and noncoding RNA transcripts, and has recently been recognized has a novel epigenetic mechanism in GC pathogenesis. More specifically, A-to-I editing of AZIN1 transcripts was shown to be regulated by an adenosine deaminase acting on RNA-1 (ADAR1), and edited AZIN1 resulted in an aggressive phenotype during disease progression in some human cancers. The aim of this study was to clarify the clinical consequences of RNA editing status of AZIN1 and the RNA editing enzymes (ADAR1 and 2) in GC patients. Methods. Two hundred eighty-eight gastric specimens from one hundred forty-four patients who underwent surgery for GC were evaluated. We analyzed the RNA editing status of AZIN1 by RNA editing site-specific quantitative PCR (RESSqPCR). RESSqPCR allows quantitation of RNA editing levels using wild-type or edited AZIN1-specific primers, and RNA editing levels are calculated by determining the ratios of Ct values between edited vs. wild-type transcript expression levels. Furthermore, expression levels of ADAR1 and ADAR2 were evaluated by qPCR in GC tissues. Results. We observed a higher frequency of the AZIN1 RNA editing in tumors compared with normal mucosa in GC. RNA editing status of AZIN1 was significantly increased in a stage-dependent manner, and high frequency of RNA editing in AZIN1 significantly correlated with advanced T stage and presence of lymph node metastasis in GC patients. Multivariate analysis revealed that high frequency of RNA editing in the AZIN1 gene was an independent prognostic factor for poor disease free survival and overall survival. Furthermore, significant upregulation of ADAR1 and downregulation of ADAR2 was also observed in GC tissues compared with matched normal mucosa, and these alterations also significantly correlated with disease progression factors and poor prognosis in GC patients. Interestingly, ADAR1 expression level was positively correlated with RNA editing status of AZIN1 in GC tissues. Conclusions. Our findings revealed that altered gene-specific A-to-I editing events mediated by ADAR1 promote disease progression in GC. We conclude that assessment of RNA editing status of the AZIN1 gene might offer a novel and superior biomarker for a more accurate diagnosis of disease staging and may help predict clinical outcomes in GC patients. Citation Format: Yoshinaga Okugawa, Yuji Toiyama, Kunitoshi Shigeyasu, Takashi Ichikawa, Satoshi Oki, Koichiro Mori, Yuka Nagano, Hiromi Yasuda, Shigeyuki Yoshiyama, Masaki Ohi, Koji Tanaka, Yasuhiro Inoue, Toshimitsu Araki, Yasuhiko Mohri, Motoyoshi Tanaka, Chikao Miki, Ajay Goel, Masato Kusunoki. Novel findings for the clinical significance of RNA editing status of AZIN1 and ADAR 1 and 2 expression levels in gastric cancer patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4720. doi:10.1158/1538-7445.AM2017-4720