Current questions for the treatment of advanced gastric cancer

Big data approach in the field of gastric and colorectal cancer research

Big data is characterized by three attributes: volume, variety,, and velocity. In healthcare setting, big data refers to vast dataset that is electronically stored and managed in an automated manner and has the potential to enhance human health and healthcare system. In this review, gastric cancer (GC) and postcolonoscopy colorectal cancer (PCCRC) will be used to illustrate application of big data approach in the field of gastrointestinal cancer research. Helicobacter pylori (HP) eradication only reduces GC risk by 46% due to preexisting precancerous lesions. Apart from endoscopy surveillance, identifying medications that modify GC risk is another strategy. Population-based cohort studies showed that long-term use of proton pump inhibitors (PPIs) associated with higher GC risk after HP eradication, while aspirin and statins associated with lower risk. While diabetes mellitus conferred 73% higher GC risk, metformin use associated with 51% lower risk, effect of which was independent of glycemic control. Nonetheless, nonsteroidal anti-inflammatory drugs (NA-NSAIDs) are not associated with lower GC risk. CRC can still occur after initial colonoscopy in which no cancer was detected (i.e. PCCRC). Between 2005 and 2013, the rate of interval-type PCCRC-3y (defined as CRC diagnosed between 6 and 36 months of index colonoscopy which was negative for CRC) was 7.9% in Hong Kong, with >80% being distal cancers and higher cancer-specific mortality compared with detected CRC. Certain clinical and endoscopy-related factors were associated with PCCRC-3 risk. Medications shown to have chemopreventive effects on PCCRC include statins, NA-NSAIDs, and angiotensin-converting enzyme inhibitors/angiotensin receptor blockers.

Human epidermal growth factor receptor 2 expression level and combined positive score can evaluate efficacy of advanced gastric cancer

BACKGROUND

Although treatment options for gastric cancer (GC) continue to advance, the overall prognosis for patients with GC remains poor. At present, the predictors of treatment efficacy remain controversial except for high microsatellite instability.

AIM

To develop methods to identify groups of patients with GC who would benefit the most from receiving the combination of a programmed cell death protein 1 (PD-1) inhibitor and chemotherapy.

METHODS

We acquired data from 63 patients with human epidermal growth factor receptor 2 (HER2)-negative GC with a histological diagnosis of GC at the Cancer Hospital, Chinese Academy of Medical Sciences between November 2020 and October 2022. All of the patients screened received a PD-1 inhibitor combined with chemotherapy as the first-line treatment.

RESULTS

As of July 1, 2023, the objective response rate was 61.9%, and the disease control rate was 96.8%. The median progression-free survival (mPFS) for all patients was 6.3 months. The median overall survival was not achieved. Survival analysis showed that patients with a combined positive score (CPS) ≥ 1 exhibited an extended trend in progression-free survival (PFS) when compared to patients with a CPS of 0 after receiving a PD-1 inhibitor combined with oxaliplatin and tegafur as the first-line treatment. PFS exhibited a trend for prolongation as the expression level of HER2 increased. Based on PFS, we divided patients into two groups: A treatment group with excellent efficacy and a treatment group with poor efficacy. The mPFS of the excellent efficacy group was 8 months, with a mPFS of 9.1 months after excluding a cohort of patients who received interrupted therapy due to surgery. The mPFS was 4.5 months in patients in the group with poor efficacy who did not receive surgery. Using good/poor efficacy as the endpoint of our study, univariate analysis revealed that both CPS score (P = 0.004) and HER2 expression level (P = 0.015) were both factors that exerted significant influence on the efficacy of treatment the combination of a PD-1 inhibitor and chemotherapy in patients with advanced GC (AGC). Finally, multivariate analysis confirmed that CPS score was a significant influencing factor.

CONCLUSION

CPS score and HER2 expression both impacted the efficacy of immunotherapy combined with chemotherapy in AGC patients who were non-positive for HER2.

BPTF Drives Gastric Cancer Resistance to EGFR Inhibitor by Epigenetically Regulating the C-MYC/PLCG1/Perk Axis

Erlotinib, an EGFR tyrosine kinase inhibitor, is used for treating patients with cancer exhibiting EGFR overexpression or mutation. However, the response rate of erlotinib is low among patients with gastric cancer (GC). The findings of this study illustrated that the overexpression of bromodomain PHD finger transcription factor (BPTF) is partially responsible for erlotinib resistance in GC, and the combination of the BPTF inhibitor AU-1 with erlotinib synergistically inhibited tumor growth both in vivo and in vitro. AU-1 inhibited the epigenetic function of BPTF and decreased the transcriptional activity of c-MYC on PLCG1 by attenuating chromosome accessibility of the PLCG1 promoter region, thus decreasing the expression of p-PLCG1 and p-Erk and eventually improving the sensitivity of GC cells to erlotinib. In patient-derived xenograft (PDX) models, AU-1 monotherapy exhibited remarkable tumor-inhibiting activity and is synergistic anti-tumor effects when combined with erlotinib. Altogether, the findings illustrate that BPTF affects the responsiveness of GC to erlotinib by epigenetically regulating the c-MYC/PLCG1/pErk axis, and the combination of BPTF inhibitors and erlotinib is a viable therapeutic approach for GC.

Role of Metabolomics in Pathogenesis and Prompt Diagnosis of Gastric Cancer Metastasis-A Systematic Review

INTRODUCTION

Gastric cancer is the fourth most frequently diagnosed form of cancer and the third leading cause of cancer-related mortality worldwide. The aim of this review is to identify individual metabolic biomarkers and their association with accurate diagnostic values, which can predict gastric cancer metastasis.

MATERIALS AND METHODS

After searching the keywords, 83 articles were found over a period of 13 years. One was eliminated because it was not written in English, and two were published outside the selected period. Seven scientific papers were qualified for this investigation after eliminating duplicates, non-related articles, systematic reviews, and restricted access studies.

RESULTS

New metabolic biomarkers with predictive value for gastric cancer metastasis and for elucidating metabolic pathways of the metastatic process have been found. The pathogenic processes can be outlined as follows: pro-oxidant capacity, T-cell inactivation, cell cycle arrest, energy production and mitochondrial enzyme impairment, cell viability and pro-apoptotic effect, enhanced degradation of collagen extracellular matrix, migration, invasion, structural protein synthesis, and tumoral angiogenesis.

CONCLUSION

Metabolic biomarkers have been recognized as independent risk factors in the molecular process of gastric cancer metastasis, with good diagnostic and prognostic value.

Tumor-associated macrophage-derived GDNF promotes gastric cancer liver metastasis via a GFRA1-modulated autophagy flux

PURPOSE

Liver metastasis, a lethal malignancy of gastric cancer (GC) patients, execrably impairs their prognosis. As yet, however, few studies have been designed to identify the driving molecules during its formation, except screening evidence pausing before their functions or mechanisms. Here, we aimed to survey a key driving event within the invasive margin of liver metastases.

METHODS

A metastatic GC tissue microarray was used for exploring malignant events during liver-metastasis formation, followed by assessing the expression patterns of glial cell-derived neurotrophic factor (GDNF) and GDNF family receptor alpha 1 (GFRA1). Their oncogenic functions were determined by both loss- and gain-of-function studies in vitro and in vivo, and validated by rescue experiments. Multiple cell biological studies were performed to identify the underlying mechanisms.

RESULTS

In the invasive margin, GFRA1 was identified as a pivotal molecule involved in cellular survival during liver metastasis formation, and we found that its oncogenic role depends on tumor associated macrophage (TAM)-derived GDNF. In addition, we found that the GDNF-GFRA1 axis protects tumor cells from apoptosis under metabolic stress via regulating lysosomal functions and autophagy flux, and participates in the regulation of cytosolic calcium ion signalling in a RET-independent and non-canonical way.

CONCLUSION

From our data we conclude that TAMs, homing around metastatic nests, induce the autophagy flux of GC cells and promote the development of liver metastasis via GDNF-GFRA1 signalling. This is expected to improve the comprehension of metastatic pathogenesis and to provide a novel direction of research and translational strategies for the treatment of metastatic GC patients.

Chromatin and noncoding RNA-mediated mechanisms of gastric tumorigenesis

Gastric cancer (GC) is one of the most common and deadly cancers in the world. It is a multifactorial disease highly influenced by environmental factors, which include radiation, smoking, diet, and infectious pathogens. Accumulating evidence suggests that epigenetic regulators are frequently altered in GC, playing critical roles in gastric tumorigenesis. Epigenetic regulation involves DNA methylation, histone modification, and noncoding RNAs. While it is known that environmental factors cause widespread alterations in DNA methylation, promoting carcinogenesis, the chromatin- and noncoding RNA-mediated mechanisms of gastric tumorigenesis are still poorly understood. In this review, we focus on discussing recent discoveries addressing the roles of histone modifiers and noncoding RNAs and the mechanisms of their interactions in gastric tumorigenesis. A better understanding of epigenetic regulation would likely facilitate the development of novel therapeutic approaches targeting specific epigenetic regulators in GC.

The relationship of different preoperative inflammatory markers with the prognosis of gastric carcinoma

BACKGROUND

It is aimed to determine the prognostic values of preoperative inflammatory biomarkers in patients undergoing curative surgery for gastric carcinoma and to contribute to the development of prognostic modeling.

OBJECTIVE

To investigate the effect of various different preoperative inflammatory markers on the prognosis of gastric carcinoma.

MATERIAL AND METHOD

The medical data and the mortality status of 91 patients who underwent total or subtotal gastrectomy operation for gastric carcinoma at Mersin City Training and Research Hospital between 2016 and 2020 were retrospectively reviewed from the hospital records and patient files. The patients' demographic characteristics, tumor location, histopathological diagnosis, pathological stage, tumor markers, and preoperative inflammatory and hematological markers were analyzed. Based on these data, tumor stage, metastatic lymph node ratio (MLR), lactate dehydrogenase albumin ratio (LAR), neutrophil-lymphocyte ratio (NLR), and platelet lymphocyte ratio (PLR) were calculated. The relationship between these parameters and postoperative survival was analyzed. Statistical analyses were performed with IBM SPSS for Windows, version 17.0 (IBM Corporation, Armonk, New York, United States).

RESULTS

The correlation analysis of the parameters affecting survival showed that, in addition to an advanced tumor stage, inflammatory parameters like NLR, PLR, and LAR adversely affected survival.

CONCLUSION

Preoperative NLR, PLR, LAR, and advanced tumor stage may help determine the survival of gastric carcinoma patients. Multiple studies with larger series are needed on this subject.

Efficacy and Safety of Camrelizumab in Combination with Docetaxel + S-1 Sequenced by Camrelizumab + S-1 for Stage III (PD-1+/MSI-H/EBV+/dMMR) Gastric Cancer: Study Protocol for a Single-Center, Prospective, Open-Label, Single-Arm Trial

Background

Gastric cancer occupies the fourth highest morbidity rate of cancers worldwide. A higher incidence of gastric cancer had been found in East Asia compared to the other regions. Gastrectomy with radical lymph node dissection is the cornerstone of curative treatment for Stage III gastric cancer, and postoperative systemic chemotherapy with docetaxel, S-1 improved patients’ disease-free survival rates. However, advances in immunotherapy bring innovations in the management of patients with gastric cancer. The objective of this study was to explore the efficacy and safety of camrelizumab in combination with docetaxel + S-1, sequenced by camrelizumab + S-1 in stage III gastric cancer patients who are EBV positive, with defective mismatch repair and CPS ≥5.

Methods and analysis

This prospective, open-label, single-arm trial was performed at Renji Hospital. In this study, a total of 70 adult patients aged 18–80 years with Stage III (PD-1+/MSI-H/EBV+/dMMR) gastric cancer confirmed by post-operative pathology will be enrolled after screening. Participants will receive the specific chemotherapy regimen until 1 year after the operation or until tumor recurrence or metastasis. The primary outcome is the 3-year disease-free survival rate measured by the Clopper-Pearson method and 95% confidence intervals. The secondary outcomes include overall survival, incidence and severity of adverse effects, and laboratory abnormalities. The data will be analyzed by the Kaplan-Meier method and log-rank test. The patients will be followed up every 3 months with imaging investigation until clinical remission.

Ethics and dissemination

All participants will provide informed consent. The protocol has been approved by the Shanghai Jiaotong University School of Medicine, Renji Hospital Ethics Committee (KY2019-191). The results will be disseminated through peer-reviewed manuscripts, reports and presentations.

Clinical Trial Registration

ClinicalTrials.gov, identifier: ChiCTR1900027123. Registration date November 2019; first enrolment December 2019; expected end date December 2021; trial status: Ongoing.

Brief Abstract

A clinical trial for Stage III (PD-1+/MSI-H/EBV+/dMMR) gastric cancer patients who accepted anti-PD-1 therapy combined with docetaxel + S-1 as the first-line treatment and explored improvements in three-year disease-free survival rate.

Statins associate with lower risk of biliary tract cancers: A systematic review and meta-analysis

BACKGROUND

Biliary tract cancers (BTCs), encompassing cholangiocarcinoma (CCA), gallbladder (GBC), and ampulla of Vater cancers (AVC), are common hepatobiliary cancer after hepatocellular carcinoma with a high mortality rate. As there is no effective chemopreventive agent to prevent BTCs, this study aimed to explore the role of statins on the risk of BTCs.

METHODS

PubMed, Embase, and Cochrane Library from inception until 24 April 2020 were searched according to the Meta-Analyses of Observational Studies in Epidemiology (MOOSE) guidelines. The adjusted risk ratios (aRRs) of BTCs and individual cancer were pooled using a random-effects model.

RESULTS

Eight observational studies (3 cohort and 5 case-control studies) were included with 10,485,231 patients. The median age was 68.0 years (IQR: 67.0-71.5) and 48.3% were male. Statins were associated with a lower risk of all BTCs (aRR: 0.67; 95% CI: 0.51-0.87). The pooled aRR for CCA was 0.60 (95% CI: 0.38-0.94) and GBC was 0.78 (95% CI: 0.68-0.90). There was only one study on AVC with aRR of 0.96 (95% CI: 0.66-1.41). The pooled aRR for lipophilic and hydrophilic statins was 0.78 (95% CI: 0.69-0.88) and 0.70 (95% CI: 0.61-0.80), respectively. The effects were attenuated in studies that adjusted for aspirin and/or non-steroidal anti-inflammatory drugs (aRR: 0.80, 95% CI: 0.72-0.89) and metformin (aRR: 0.80, 95% CI: 0.72-0.90).

CONCLUSIONS

Statins, both lipophilic and hydrophobic, were associated with a lower risk of BTCs, particularly CCA and GBC.

Silencing of Long Non-coding RNA LINC01106 Represses Malignant Behaviors of Gastric Cancer Cells by Targeting miR-34a-5p/MYCN Axis

Long non-coding RNA LINC01106 is an lncRNA aberrantly expressed in gastric cancer (GC). However, the accurate function remains unclear. The objective of this investigation is to explore detailed regulatory mechanism of lncRNA LINC01106 in GC. The expression of lncRNA LINC01106, MYCN, and miR-34a-5p was determined by quantitative real-time polymerase chain reaction (qRT-PCR). Cell viability was examined using MTT assay. Migratory and invasive abilities of GC cells were evaluated by transwell assay. The targeting relation among lncRNA LINC01106, MYCN, and miR-34a-5p was tested by dual-luciferase reporter (DLR) assay. Relative protein expression of MYCN was assessed via western blot. Besides, a xenograft mouse model was established to assess the role of LINC01106 in GC in vivo. LncRNA LINC01106 and MYCN expression were boosted and miR-34a-5p expression was reduced in GC cells and tissues compared to their controls. Functionally, decreased lncRNA LINC01106 or increased miR-34a-5p restrained GC cells in viability, invasion, and migration in vitro. LINC01106 down-regulation suppressed tumor growth of mice in vivo. In terms of mechanism, lncRNA LINC01106 directly targeted miR-34a-5p and was inversely correlated with miR-34a-5p. MYCN was targeted by miR-34a-5p and was inversely correlated with miR-34a-5p. There was a positive correlation between LINC01106 and MYCN. LINC01106 knockdown led to the suppression of cell invasion, migration, and viability, whereas these effects caused by LINC01106 knockdown were reversed by miR-34a-5p down-regulation or MYCN up-regulation in GC cells. Silencing of lncRNA LINC01106 attenuated cell viability, invasion, and migration by sponging miR-34a-5p to target MYCN in GC.

Circ_0003159 upregulates LIFR expression through competitively binding to miR-221-3p/miR-222-3p to block gastric cancer development

Gastric cancer (GC) remains a major cause of cancer-related deaths. Increasing studies suggest that cancer development is accompanied by the deregulation of circular RNAs. We investigated the function of circ_0003159 in GC. The expression levels of circ_0003159, miR-221-3p/miR-222-3p and leukemia inhibitory factor receptor (LIFR) mRNA were measured by real-time quantitative polymerase chain reaction. Cell colony formation ability was assessed by colony formation assay, and cell viability was assessed by cell counting kit-8 assay. Cell apoptosis was assessed by flow cytometry assay and caspase3 activity. Cell migration and invasion were assessed by transwell assay. Glycolysis energy metabolism was assessed by 5'-triphosphate production, glucose uptake and lactate production. The protein levels of related marker proteins and LIFR were detected by western blot. The relationship between circ_0003159 and miR-221-3p/miR-222-3p, or LIFR and miR-221-3p/miR-222-3p was obtained from bioinformatics tools and verified by dual-luciferase reporter assay. A cancer tumorogenicity xenograft experiment in nude mice was conducted to determine the role of circ_0003159 in tumor growth by AGS cells. Our results showed that circ_0003159 expression was decreased in GC tissues and cells. Circ_0003159 overexpression sequestered GC cell viability, migration, invasion and glycolysis and induced cell apoptosis. MiR-221-3p and miR-222-3p were targets of circ_0003159, and the inhibition of miR-221-3p and miR-222-3p also blocked GC cell viability, migration, invasion and glycolysis and promoted cell apoptosis. LIFR was a common target of miR-221-3p and miR-222-3p. Interestingly, LIFR knockdown reversed the effects of circ_0003159 overexpression on GC cell behaviors. Circ_0003159 increased the expression level of LIFR by targeting miR-221-3p and miR-222-3p. The tumorigenicity assay showed that circ_0003159 overexpression inhibited tumor growth in vivo. In conclusion, circ_0003159 inhibited GC development in vitro and in vivo by enriching the level of LIFR via direct binding to miR-221-3p/miR-222-3p.

Bcl2-associated athanogene 4 promotes the invasion and metastasis of gastric cancer cells by activating the PI3K/AKT/NF-κB/ZEB1 axis

Bcl2-associated athanogene 4 (BAG4) has been found to be aberrantly expressed in several types of human cancers. However, little is known about its expression, role, and clinical significance in gastric cancer (GC). In this study, we aimed to address these issues and to explore the underlying mechanisms. The expression level of BAG4, measured by immunohistochemistry, was significantly higher in GC tissues than in paired normal tissues. Elevated BAG4 expression was positively correlated with T stage, lymph node metastasis, and tumor size of GC and was associated with unfavorable outcomes of the patients. The overexpression of BAG4 promoted the in vitro invasion and in vivo metastasis of GC cells, and opposite results were observed after silencing of BAG4. Silencing of BAG4 significantly reduced the phosphorylation of PI3K, AKT, and p65, whereas overexpression of BAG4 markedly enhanced the phosphorylation of these molecules. At the same time, manipulating BAG4 expression resulted in the corresponding changes in p65 nuclear translocation and ZEB1 expression. Luciferase reporter and chromatin immunoprecipitation assays verified that p65 binds to the promoter of ZEB1 to upregulate its transcription. Our results demonstrate that BAG4 plays an oncogenic role in the invasion and metastasis of GC cells by activating the PI3K/AKT/NF-κB/ZEB1 axis to induce epithelial-mesenchymal transition.

Quantitative difference of oral pathogen between individuals with gastric cancer and individuals without cancer

The loss of teeth and lack of oral hygiene have been associated with the risk of developing gastric cancer (GC) in several populations evidenced in epidemiological studies. In this study, we quantitatively compared the proportion of oral pathogens in individuals with gastric cancer and individuals without cancer in a referral hospital in the city of Belém, Brazil. This study evaluated 192 patients with GC and 192 patients without cancer. Periodontal clinical examination was performed, and all individuals were submitted to the collection of salivary and dental biofilms. When comparing the median periodontal indexes in the gastric and cancer-free groups, it was statistically significant (p < 0.001) in the gastric cancer group compared to the probing depth of the periodontal pocket. Levels of bacterial DNA were observed in saliva and dental plaque, with a statistically significant difference (p < 0.001) between individuals with cancer and without neoplasia in all the bacteria surveyed. Significant relationships (p < 0.001) between biological agents and GC have been found in bacterial species that cause high rates of periodontal pathology and caries. The results suggest a different quantitative association in the presence of oral pathogens between individuals without cancer and patients with GC. As noted, it cannot be said that the bacteria present in the oral cavity increase the risk of gastric cancer or are aggravating factors of the disease. However, it is worth mentioning that, as it is part of the digestive system, the lack of care for the oral cavity can negatively affect the treatment of patients with gastric cancer.

Entecavir vs Tenofovir in Hepatocellular Carcinoma Prevention in Chronic Hepatitis B Infection: A Systematic Review and Meta-Analysis

Entecavir (ETV) and tenofovir disoproxil fumarate (TDF) are recommended as first-line therapies for chronic hepatitis B (CHB) infection. Although both drugs reduce hepatocellular carcinoma (HCC) risk, their comparative effectiveness remains controversial. We aimed to determine whether TDF is superior to ETV in preventing HCC.

Chemopreventive Effect of Metformin on Gastric Cancer Development

Although Helicobacterpylori infection is the most important causative factor for gastric cancer (GC), H. pylori eradication alone does not completely eliminate the GC risk. In addition to H. pylori eradication, other risk factors for GC should be identified and targeted. Diabetes mellitus (DM) confers a 20% increased risk of GC, which could be mediated via several biological mechanisms including the stimulation of cell proliferation via hyperinsulinemia and increased insulin-growth factor production, the promotion of angiogenesis, and DNA damage. With a current global prevalence of 9.3% and a predicted rise to 10.2% by 2030, DM could contribute substantially to the burden of GC cases worldwide. Emerging evidence showed that metformin possesses chemopreventive effects via both direct (e.g., adenosine monophosphate-activated protein kinase activation and subsequent inhibition of the mammalian target of rapamycin pathway) and indirect (e.g., modulation of the interaction between tumor cells and their microenvironment and gut microbiota) pathways. A recent meta-analysis of observational studies showed that metformin use was associated with 24% lower GC risk. However, many available observational studies related to metformin effects suffered from biases including the failure to adjust for the H. pylori infection status and serial glycemic control and time-related biases. Future prospective studies addressing these pitfalls are needed.

LRP4 promotes migration and invasion of gastric cancer under the regulation of microRNA-140-5p

BACKGROUND

Low-density lipoprotein receptor-related protein 4 (LRP4) has been reported to be implicated in multiple types of cancers. However, the significance of LRP4 in gastric cancer (GC) remains poorly elucidated. Therefore, it's urgent to investigate the importance and underlying mechanisms of LRP4 in GC.

OBJECTIVE

To investigate the clinical roles of LRP4 in GC.

METHODS

The LRP4 mRNA and miR-140-5p was measured by qRT-PCR. The protein expression was determined Western blot. Kaplan-Meier survival curves and Cox proportional hazard regression models were performed to evaluate prognosis.

RESULTS

We demonstrated that LRP4 mRNA and protein was up-regulated in GC tissues for the first time. Its high expression was significantly correlated with malignant clinical features including TNM stage and lymph-node metastasis and poor prognosis for GC patients. LRP4 promotes migration, invasion and epithelial-mesenchymal transition (EMT) progress of GC cells. Mechanically, LRP4 regulated PI3K/AKT in GC cells. AKT inhibitors reversed the effects of LRP4. Finally, LRP4 was regulated by miR-140-5p in GC.

CONCLUSIONS

Our findings showed that LRP4 has an important function in GC progression and promotes GC migration, invasion and EMT by regulating PI3K/AKT under regulation of miR-140-5p, providing a potential therapeutic target for GC.

The clinicopathological significance and predictive value for immunotherapy of programmed death ligand-1 expression in Epstein-Barr virus-associated gastric cancer

The effect of anti-programmed cell death 1 (PD-1) antibody in Epstein-Barr virus-associated gastric cancer (EBVaGC) was debatable, and no predictive biomarkers for efficacy have been reported. Public reports on anti-PD-1 antibody monotherapy-treated EBVaGC with available programmed death ligand-1 (PD-L1) expression status were summarized and analyzed. Relevance with clinicopathologic characteristics of PD-L1 expression by immunohistochemistry was analyzed in 159 patients diagnosed with EBVaGC. Relevance with genomic transcriptome and mutation profile of PD-L1 status in EBVaGC was assessed with three datasets, the cancer genome atlas (TCGA), Gene Expression Omnibus (GEO) GSE51575, and GSE62254. Based on the data from 8 reports, patients with positive PD-L1 expression (n = 30) had significantly superior objective response rate (ORR) than patients with negative PD-L1 expression (n = 9) (63.3% vs. 0%, P = .001) in EBVaGC receiving anti-PD-1 antibody monotherapy. PD-L1 positivity was associated with less aggressive clinicopathological characteristics and was an independent predictor for a longer disease-free survival (hazard ratio [HR] and 95% CI: 0.45 [0.22–0.92], P = .03) and overall survival (HR and 95% CI: 0.17 [0.06–0.43], P < .001). Analysis of public EBVaGC transcriptome and mutation datasets revealed enhanced immune-related signal pathways in PD-L1^high EBVaGC and distinct mutation patterns in PD-L1^low EBVaGC. PD-L1 positivity indicates a subtype of EBVaGC with ‘hot’ immune microenvironment, lower aggressiveness, better prognosis, and higher sensitivity to anti-PD-1 immunotherapy.

BCAT1 Activates PI3K/AKT/mTOR Pathway and Contributes to the Angiogenesis and Tumorigenicity of Gastric Cancer

BACKGROUND

Focusing on antiangiogenesis may provide promising choices for treatment of gastric cancer (GC). This study aimed to investigate the mechanistic role of BCAT1 in the pathogenesis of GC, particularly in angiogenesis.

METHODS

Bioinformatics and clinical samples analysis were used to investigate the expression and potential mechanism of BCAT1 in GC. BGC823 cells with BCAT1 overexpression or silencing were induced by lentiviral transduction. Cell phenotypes and angiogenesis were evaluated. The relevant proteins were quantized by Western blotting, immunohistochemistry, or immunofluorescence. Xenograft models were constructed to confirm the role of BCAT1 in vivo.

RESULTS

BCAT1 was overexpressed in GC patients and associated with lower survival. BCAT1 expression was correlated with proliferation-, invasion-, or angiogenesis-related markers expression and pathways. Silencing BCAT1 expression suppressed cell viability, colony formation, cycle progression, invasion, and angiogenesis of BGC823 cells, as well as the tumor growth of xenograft models, whereas overexpressing BCAT1 had the opposite results both in vitro and in vivo. Bioinformatics analysis and Western blotting demonstrated that BCAT1 activated the PI3K/AKT/mTOR pathway. The addition of LY294002 reversed the tumor growth induced by BCAT1 overexpression, further verifying this mechanism.

CONCLUSION

BCAT1 might act as an oncogene by facilitating proliferation, invasion, and angiogenesis through activation of the PI3K/AKT/mTOR pathway. This finding could aid the optimization of antiangiogenesis strategies.

Sema3C promotes hepatic metastasis and predicts poor prognosis in gastric adenocarcinoma

OBJECTIVE

Semaphorin 3C (Sema3C) may regulate tumor metastasis and prognosis. We determined the biological roles of Sema3C in the hepatic metastasis of gastric adenocarcinoma and evaluated its clinical significance as a potential biomarker.

METHODS

Sema3C expression in gastric cancer (GC) cell lines and tissues was measured using RT-qPCR and western blotting. Moreover, Sema3C functions were analyzed using Transwell assays and in vitro metastasis assays in gain- and loss-of-function experiments. Furthermore, the impact of Sema3C on the prognosis of 80 randomly selected patients with GC was investigated by immunohistochemistry. Additionally, the expression of epithelial-mesenchymal transition (EMT) indicators was verified by immunohistochemistry in GC tissues.

RESULTS

Sema3C expression was significantly upregulated in highly metastatic GC cell lines and tissues. Additionally, Sema3C promoted invasion, migration and hepatic metastasis in GC cells. Moreover, Sema3C expression was positively correlated with clinicopathological features in GC and paired hepatic metastatic tissues, and Sema3C expression was an independent prognostic factor. Finally, Sema3C expression was associated with node metastasis, hepatic metastasis and EMT marker expression.

CONCLUSIONS

Sema3C may play roles in regulating the EMT and metastasis of gastric adenocarcinoma, highlighting its potential use as a prognostic factor for hepatic metastasis and poor prognosis in gastric adenocarcinoma.

MicroRNA-552 Accelerates the Progression of Gastric Cancer by Targeting FOXO1 and Regulating PI3K/AKT Pathway

The specific function of microRNA-552 (miR-552) has been investigated in several malignancies, except gastric cancer (GC). Therefore, this study was performed to determine the role of miR-552 in GC.GC tissues and adjacent non-tumor tissues were collected to determine the expressions of miR-552. Quantitative real-time polymerase chain reaction assays (RT-qPCR) and Western blot analysis were carried out to measure expression levels. The regulatory mechanism of miR-552 was explored by (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) MTT Assay, and Transwell assays. The binding site between miR-552 and FOXO1 was verified by dual-luciferase reporter assays. Upregulation of miR-552 expression was detected and associated with worse clinical outcomes in GC. Furthermore, high miR-552 expression predicted poor prognosis in GC patients. Functionally, upregulation of miR-552 promoted cell viability, metastasis, epithelial-mesenchymal transition (EMT), and phosphatidylinositol 3-kinase and protein kinase B (PI3K/AKT) pathway in GC. In addition, miR-552 was confirmed to target forkhead box O1 (FOXO1) directly and inversely regulate its expression in GC. Upregulation of FOXO1 reversed the carcinogenesis of miR-552 in GC. In conclusion, miR-552 serves as a tumor promoter in GC through targeting FOXO1 and regulating EMT and PI3K/AKT pathway.

Effects of Systemic Lidocaine on Postoperative Recovery Quality and Immune Function in Patients Undergoing Laparoscopic Radical Gastrectomy

Objective

This study aimed to explore the effects of lidocaine on postoperative quality of recovery (QoR) and immune function in patients undergoing laparoscopic radical gastrectomy.

Methods

In total, 135 patients were enrolled and were equally randomized to receive low-dose lidocaine (Group LL: 1.5 mg/kg bolus followed by an infusion at 1.0 mg/kg/hour) or high-dose lidocaine (Group HL: 1.5 mg/kg bolus followed by an infusion at 2.0 mg/kg/hour) or Controls (Group C: received a volume-matched normal saline at the same rate). The primary outcome was a QoR-40 score on postoperative day (POD) 1. Secondary outcomes were a QoR-40 score on POD 3, levels of inflammatory factors (IL-6, IL-10, TNF-α) and CD4⁺T cells, CD8⁺T cells proportions, and CD4⁺/CD8⁺ cell ratios and postoperative recovery of bowel function.

Results

There were no statistically significant differences in patient characteristics at baseline. The total QoR-40 scores on POD 1 in Group HL (171.4±3.89) were higher than those in Group LL (166.20±4.05) and in Group C (163.40±4.38) (adjusted P<0.001). Differences in the dimension scores of QoR-40 for pain, physical comfort, and emotional state were significant across the three groups. Lidocaine administration significantly reduced the release of IL-6, IL-10, TNF-α, and attenuated immune changes induced by trauma. Kaplan–Meier curves showed that the median time to the first exhaust and defecation were shorter in the Group HL than in Groups LL and C (1.55 days vs 2.4 days vs 2.6 days, log rank P<0.0001; and 2.86 days vs 3.22 days vs 3.46 days, log rank P=0.002, respectively). Additionally, patients in lidocaine groups required less remifentanil consumption and experienced lower pain intensity, compared with the control group.

Conclusion

Systemic lidocaine improved postoperative recovery, alleviated inflammation and immunosuppression, and accelerated the return of bowel function, and is thus, worthy of clinical application.

Clinical Trials Registration

ChiCTR2000028934.

Increased CD44 Expression and MEK Activity Predict Worse Prognosis in Gastric Adenocarcinoma Patients Undergoing Gastrectomy

PURPOSE

We have shown that activation of the receptor tyrosine kinase (RTK)-RAS pathway in gastric adenocarcinoma (GA) promotes acquisition of cancer stem-like cell (CSC) phenotypes including metastasis and chemotherapy resistance. Here, we evaluated the prognostic value of the CSC marker CD44 and the RTK-RAS activation marker phosphorylated MEK (p-MEK) in patients with resectable GA.

METHODS

CD44 and p-MEK were measured in tumors from GA patients who underwent curative-intent gastrectomy at Fujian Medical University Union Hospital (FMUUH, n = 134) and Memorial Sloan Kettering Cancer Center (MSKCC, n = 56). Overall survival (OS) was estimated by the Kaplan-Meier method, and multivariate analysis was performed by Cox proportional hazards regression modeling.

RESULTS

Despite multiple significant differences in clinicopathologic characteristics between the FMUUH and MSKCC cohorts, high CD44 and high p-MEK expression were both independent negative prognostic factors for OS on univariate analysis in both cohorts (p < 0.05). Both factors were also significant on multivariate analysis when the cohorts were combined (p ≤ 0.003). On subgroup analysis, the 5-year OS of patients with both high CD44 and high p-MEK was 39.5-41.6% compared with 55.4-66.4% for patients with low CD44. High CD44 expression was associated with more advanced TNM stage in the FMUUH cohort and larger tumor size and undifferentiated histology in the MSKCC cohort. High p-MEK was associated with undifferentiated histology in the FMUUH cohort and larger tumor size in the MSKCC cohort.

CONCLUSIONS

Increased CD44 and p-MEK expression are predictive of worse OS in GA patients. Thus, targeting the RTK-RAS pathway may benefit patients with CD44-positive, RAS-activated GA by inhibiting metastasis and reversing chemotherapy resistance.

Molecularly targeted therapy for advanced gastrointestinal noncolorectal cancer treatment: how to choose? Past, present, future

Gastrointestinal cancer is a leading cause of death worldwide. Conventional cytotoxic chemotherapy has been the backbone of advanced gastrointestinal cancer treatment for decades and still represents a key element of the therapeutic armamentarium. However, only small increments in survival outcomes have been reached. New clinical trials are designed, including classic chemotherapy in association with either small-molecule inhibitors or mAb. During the past few years, remarkable progress in molecular biology of gastrointestinal noncolorectal cancers, the discovery of specific targets and the resulting development of systemic drugs that block critical kinases and several molecular pathways have all contributed to progress. New biological agents with molecularly targeted therapies are now available or currently included in clinical trials (EGFR inhibitors (i), antiangiogenic agents, c-METi, IDHi, FGFR2i, BRAFi, Pi3Ki/AKTi/mTORi, NTRKi). When we focus on the current state of precision medicine for gastrointestinal malignancies, it becomes apparent that there is a mixed history of success and failure. The aim of this review is to focus on the studies that have been completed to date with target therapies and to understand which of these are currently the accepted choice in clinical practice and which need further confirmation and approval for inclusion in guidelines. All these findings will enable to guide clinical practice for oncologists in the design of the next round of clinical trials.

ZEB1-induced LINC01559 expedites cell proliferation, migration and EMT process in gastric cancer through recruiting IGF2BP2 to stabilize ZEB1 expression

Gastric cancer (GC) is a common type of tumor that is characterized with high metastatic rate. In recent years, increasing studies have indicated that lncRNAs are involved in the regulation on cancer cell proliferation and migration. However, the functional role of long intergenic non-protein coding RNA 1559 (LINC01559) in GC is still unclear. In this study, we applied quantitative real-time polymerase chain reaction (RT-qPCR) and examined that LINC01559 expression was significantly enhanced in GC cells. Functional assays such as EdU, colony formation, JC-1 and transwell assays displayed that silencing LINC01559 inhibited cell proliferation and migration while promoted cell apoptosis in GC. Besides, western blot analysis and immunofluorescence assays examined the expression of factors related to epithelial-mesenchymal transition (EMT) and indicated that EMT process was blocked by LINC01559 knockdown in GC cells. Besides, LINC01559 silencing inhibited tumor growth in vivo. In addition, Chromatin immunoprecipitation (ChIP) assays demonstrated that zinc finger E-box binding homeobox 1 (ZEB1) served as a transcription factor to combine with LINC01559 promoter and activated the expression of LINC01559 in GC cells. In return, LINC01559 recruited insulin like growth factor 2 mRNA binding protein 2 (IGF2BP2) to stabilize ZEB1 mRNA to up-regulate ZEB1 in GC cells. In short, the findings in this research might provide a novel target for GC treatment.

Luteolin alters MUC1 extracellular domain, sT antigen, ADAM-17, IL-8, IL-10 and NF-κB expression in Helicobacter pylori-infected gastric cancer CRL-1739 cells: A preliminary study

Luteolin is a natural flavonoid possessing certain beneficial pharmacological properties, including anti-oxidant, anti-inflammatory, anti-microbial and anti-cancer properties. The majority of types of gastric cancer with chronic gastritis are caused by infection with Helicobacter pylori (H. pylori). The present study evaluated the effect of luteolin on a number of selected factors that are potentially involved in gastric cancer development. The study was performed using gastric cancer CRL-1739 cells treated with 30 µM luteolin and H. pylori alone or combined. ELISA and reverse transcription PCR were used to assess the expression levels of MUC1, GalNAcα-R (Tn antigen) and NeuAcα2-3Galβ1-3GalNAc-R (sT antigen), ADAM-17, IL-8, IL-10 and NF-κB. H. pylori and luteolin independently and in combination significantly reduced the expression levels of the extracellular domain of MUC1 in gastric cancer cells compared with the untreated control cells. ADAM-17 expression was reduced by treatment with the pathogen and luteolin. Additionally, both factors reduced sT antigen expression. Treatment with 30 ≤M luteolin significantly induced IL-8 expression at the mRNA and protein level, and the mRNA expression levels of IL-10 and NF-κB compared with the control. Both H. pylori and luteolin induced IL-8 protein expression. The present preliminary results suggest that luteolin may be used to treat patients with gastric cancer.

Screening lncRNAs with diagnostic and prognostic value for human stomach adenocarcinoma based on machine learning and mRNA-lncRNA co-expression network analysis

BACKGROUND

Stomach adenocarcinoma (STAD), is one of the most lethal malignancies around the world. The aim of this study was to find the long noncoding RNAs (lncRNAs) acting as diagnostic and prognostic biomarker of STAD.

METHODS

Base on TCGA dataset, the differentially expressed mRNAs (DEmRNAs) and lncRNAs (DElncRNAs) were identified between STAD and normal tissue. The machine learning and survival analysis were performed to evaluate the potential diagnostic and prognostic value of lncRNAs for STAD. We also build the co-expression network and functional annotation. The expression of selected candidate mRNAs and lncRNAs were validated by Quantitative real-time polymerase chain reaction (qRT-PCR) and GSE27342 dataset. GSE27342 dataset were also to perform gene set enrichment analysis.

RESULTS

A total of 814 DEmRNAs and 106 DElncRNAs between STAD and normal tissue were obtained. FOXD2-AS1, LINC01235, and RP11-598F7.5 were defined as optimal diagnostic lncRNA biomarkers for STAD. The area under curve (AUC) of the decision tree model, random forests model, and support vector machine (SVM) model were 0.797, 0.981, and 0.983, and the specificity and sensitivity of the three model were 75.0% and 97.1%, 96.9% and 96%, and 96.9% and 97.1%, respectively. Among them, LINC01235 was not only an optimal diagnostic lncRNA biomarkers, but also related to survival time. The expression of three DEmRNAs (ESM1, WNT2, and COL10A1) and three optimal diagnostic lncRNAs biomarkers (FOXD2-AS1, RP11-598F7.5, and LINC01235) in qRT-PCR validation was were consistent with our integrated analysis. Except for FOXD2-AS1, ESM1, WNT2, COL10A1, and LINC01235 were upregulated in STAD, which was consistent with our integration results. Gene set enrichment analysis results indicated that DNA replication, Cell cycle, ECM-receptor interaction, and P53 signaling pathway were four significantly enriched pathways in STAD.

CONCLUSION

Our study identified three DElncRNAs as potential diagnostic biomarkers of STAD. Among them, LINC01235 also was a prognostic lncRNA biomarkers.

Precision Medicine to Treat Advanced Gastroesophageal Adenocarcinoma: A Work in Progress

Gastroesophageal adenocarcinoma (GEA) represents a heterogeneous disease and, when diagnosed as locally advanced or metastatic, it is characterized by poor prognosis. During the last few years, several molecular classifications have been proposed to try to personalize treatment for those patients diagnosed with advanced disease. Nevertheless, despite the great effort, precision medicine is still far from being a reality. The improvement in the molecular analysis due to the application of high throughput technologies based on DNA and RNA sequencing has opened a novel scenario leading to the personalization of treatment. The possibility to target epidermal growth factor receptor (HER)2, Claudine, Fibroblast Growth Factor Receptors (FGFR), and other alterations with a molecular matched therapy could significantly improve clinical outcomes over advanced gastric cancer patients. On the other hand, the development of immunotherapy could also represent a promising strategy in a selected population. In this review, we sought to describe the novel pathways implicated in GEA progression and the results of the molecular matched therapies.

miR-300/FA2H affects gastric cancer cell proliferation and apoptosis

MicroRNA (miR/miRNA) expression disorders play a crucial role in the development of gastric cancer (GC). Increasing evidence has indicated that miRNAs participate in the process of numerous cancers. Previous research has demonstrated that miR-300 acts as a cancer-promoting factor or tumor suppressor in a number of tumors. However, to the best of our knowledge, the effects of miR-300 on GC cells remain largely unknown. The present study investigated the effects of miR-300 on GC cells and analyzed its molecular mechanism. First, reverse transcription-quantitative polymerase chain reaction showed that miR-300 expression was increased in GC tissues and cell lines, with the highest expression observed in human gastric cancer cell line AGS. Subsequent results indicated that fatty acid 2-hydroxylase (FA2H) was a target of miR-300. FA2H-plasmid inhibited AGS cell proliferation and induced apoptosis. Finally, miR-300 inhibitor reduced cell proliferation and induced apoptosis, whereby these effects were reversed by FA2H-small interfering RNA. Therefore, the data demonstrated that miR-300/FA2H might be a new potential biomarker and therapeutic target for GC treatment.

Gastric cancer: epidemiology, biology, and prevention: a mini review

Gastric cancer is one of the most common causes of cancer-related mortality worldwide. The objective of this article is to review the epidemiology and biology of gastric cancer risk. This literature review explores the biological, clinical, and environmental factors that influence the rates of this disease and discuss the different intervention methods that may not only increase the awareness of gastric cancer but also increase screening in efforts to reduce the risk of gastric cancer. Helicobacter pylori infection is the primary risk factor for gastric cancer. Additional risk factors include geographical location, age, sex, smoking, socioeconomic status, dietary intake, and genetics. Primary and secondary prevention strategies such as dietary modifications and screenings are important measures for reducing the risk of gastric cancer. Interventions, such as H. pylori eradication through chemoprevention trials, have shown some potential as a preventative strategy. Although knowledge about gastric cancer risk has greatly increased, future research is warranted on the differentiation of gastric cancer epidemiology by subsite and exploring the interactions between H. pylori infection, genetics, and environmental factors. Better understanding of these relationships can help researchers determine the most effective intervention strategies for reducing the risk of this disease.

TIPRL, a Novel Tumor Suppressor, Suppresses Cell Migration, and Invasion Through Regulating AMPK/mTOR Signaling Pathway in Gastric Cancer

Invasion and metastasis of gastric cancer after curative resection remain the most common lethal outcomes. However, our current understanding of the molecular mechanism underlying gastric cancer metastasis is far from complete. Herein, we identified TOR signaling pathway regulator (TIPRL) as a novel metastasis suppressor in gastric cancer through genome-wide gene expression profiling analysis using mRNA microarray. Decreased TIPRL expression was detected in clinical gastric cancer specimens, and low TIPRL expression was correlated with more-advanced TNM stage, distant metastasis, and poor clinical outcome. Moreover, TIPRL was identified as a direct target of miR-216a-5p and miR-383-5p. Functional study revealed that re-expression of TIPRL in gastric cancer cell lines suppressed their migratory and invasive capacities, whereas inverse effects were observed in TIPRL-deficient models. Mechanistically, TIPRL downstream effectors and signaling pathways were investigated using mRNA microarray. Gene expression profiling revealed that TIPRL could not modulate the downstream genes at transcriptional levels, thereby implying that the regulation might occur at the post-transcriptional levels. We further demonstrated that TIPRL induced phosphorylation/activation of AMPK, which in turn attenuated phosphorylation of mTOR, p70S6K, and 4E-BP1, thereby leading to inactivation of mTOR signaling and subsequent suppression of cell migration/invasion in gastric cancer. Taken together, TIPRL acts as a novel metastasis suppressor in gastric cancer, at least in part, through regulating AMPK/mTOR signaling, likely representing a promising target for new therapies in gastric cancer.

Towards precision oncology for HER2 blockade in gastroesophageal adenocarcinoma

Gastroesophageal adenocarcinoma (GEA) represents a very heterogeneous disease and patients in advanced stages have a very poor prognosis. Although several molecular classifications have been proposed, precision medicine for HER2-amplified GEA patients still represents a challenge. Despite improvement in clinical outcomes obtained by adding trastuzumab to first-line platinum-based chemotherapy, no other anti-HER2 agents used first-line or beyond progression have demonstrated any benefit. Several factors contribute to this failure. Among them, variable HER2 amplification assessment, tumour heterogeneity, molecular mechanisms of resistance and microenvironmental factors could limit the effectiveness of anti-HER2 blockade. Identifying the factors responsible for both primary and acquired resistance is a priority for providing an improved, personalised approach. In this review, we examine current treatments for HER2-amplified GEA, their potential mechanisms of resistance and the ways to overcome them, investigating the most relevant translational studies with anti-HER2 agents in GEA, as well as novel agents under development in this field.

Myrrh induces the apoptosis and inhibits the proliferation and migration of gastric cancer cells through down-regulating cyclooxygenase-2 expression

OBJECTIVE

The present study is designed to evaluate the anti-tumor effects of myrrh on human gastric cancer both in vitro and in vivo.

METHODS

The gastric cancer cell proliferation was determined by MTT assay. Apoptosis was measured by flow cytometry and Hoechst 33342 staining. Wound healing was performed to evaluate the effects of myrrh on the migration. COX-2, PCNA, Bcl-2, and Bax expressions were detected by Western blot analysis. A xenograft nude mice model of human gastric cancer was established to evaluate the anti-cancer effect of myrrh in vivo.

RESULTS

Myrrh significantly inhibited cellular proliferation, migration, and induced apoptosis in vitro as well as inhibited tumor growth in vivo. In addition, myrrh inhibited the expression of PCNA, COX-2, and Bcl-2 as well as increased Bax expression in gastric cancer cells.

CONCLUSION

Myrrh may inhibit the proliferation and migration of gastric cancer cells, as well as induced their apoptosis by down-regulating the expression of COX-2.

Activation of SREBP-1c alters lipogenesis and promotes tumor growth and metastasis in gastric cancer

PURPOSE

Aggressively growing tumors are characterized by significant variations in metabolites, including lipids, and can involve the elevated synthesis ofde novo fatty acids.

METHODS

Ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS)-based metabolomics and lipidomics were performed to compare human gastric cancer tissues and adjacent normal tissues from clinical patients. A series of cellular and molecular biological methods were applied to validate the lipidomics results.

RESULTS

Palmitic acid (PA) was found to be significantly downregulated in gastric cancer tissues, and it was found that a high concentration of PA specifically inhibited cell proliferation and impaired cell invasiveness and migrationin vitro in AGS, SGC-7901, and MGC-803 gastric cancer cell lines. Moreover, sterol regulatory element-binding protein 1 (SREBP-1c) was activated in human gastric cancer tissues, and it promoted the expression of a series of genes associated with the synthesis of fatty acids, such as SCD1 and FASN. SREBP-1c knockdown rescued the migration and invasion defects in AGS and SGC-7901 gastric cancer cells.

CONCLUSION

Taken together, our findings confirmed the variation in fatty acid synthesis in gastric cancer and identified SREBP-1c as a promising target for gastric cancer treatment.

miRNA-765 mediates multidrug resistance via targeting BATF2 in gastric cancer cells

Elucidation of the mechanisms underlying multidrug resistance (MDR) is required to ensure the efficacy of chemotherapy against gastric cancer (GC). To investigate this issue, here we identified that microRNA-765 (miRNA-765) is up-regulated both in MDR GC cell lines and in specimens from patients who are not responding to chemotherapy. In addition, down-regulation of miRNA-765 increased the sensitivity of GC cells to anticancer drugs, whereas its overexpression had the opposite effect. Moreover, miRNA-765 suppressed drug-induced apoptosis and positively regulated the expression of MDR-related genes. Finally, we showed that the basic leucine zipper ATF-like transcription factor 2, a tumor suppressor gene, is the functional target of miRNA-765. In summary, these results suggest that miRNA-765 may promote MDR via basic leucine zipper ATF-like transcription factor 2 in GC cells.

A functional network of gastric-cancer-associated splicing events controlled by dysregulated splicing factors

Comprehensive understanding of aberrant splicing in gastric cancer is lacking. We RNA-sequenced 19 gastric tumor–normal pairs and identified 118 high-confidence tumor-associated (TA) alternative splicing events (ASEs) based on high-coverage sequencing and stringent filtering, and also identified 8 differentially expressed splicing factors (SFs). The TA ASEs occurred in genes primarily involved in cytoskeletal organization. We constructed a correlative network between TA ASE splicing ratios and SF expression, replicated it in independent gastric cancer data from The Cancer Genome Atlas and experimentally validated it by knockdown of the nodal SFs (PTBP1, ESRP2 and MBNL1). Each SF knockdown drove splicing alterations in several corresponding TA ASEs and led to alterations in cellular migration consistent with the role of TA ASEs in cytoskeletal organization. We have therefore established a robust network of dysregulated splicing associated with tumor invasion in gastric cancer. Our work is a resource for identifying oncogenic splice forms, SFs and splicing-generated tumor antigens as biomarkers and therapeutic targets.

Circular RNAs and gastrointestinal cancers: Epigenetic regulators with a prognostic and therapeutic role

Both environmental and genetic factors are involved in the initiation and development of gastrointestinal cancer. Covalent closed circular RNAs (circRNAs) are produced by a mechanism called "back-splicing" from mRNAs. They are highly stable and show cell and tissue specific expression patterns. Although some functions such as "microRNA sponge" and "RNA binding protein sponge" have been reported for a small number of circRNAs, the function of thousands of other circRNAs is still unknown. Dysregulation of circRNAs has been reported in many GI cancers and are involved in metastasis and invasion. CircRNAs have been reported to be useful as prognostic markers and targets for developing new treatments. We first describe the properties and biogenesis of circRNAs. We then summarize recent reports about circRNA functions, expression status, and their potential to be used as biomarkers in GI cancers including, gastric cancer, colorectal cancer, esophageal cancer, hepatocellular carcinoma, gallbladder cancer and pancreatic cancer.

miR-1294 alleviates epithelial-mesenchymal transition by repressing FOXK1 in gastric cancer

BACKGROUND

MicroRNAs (miRNAs) have been reported play critical roles in regulating tumor development and progression.

OBJECTIVE

This study aimed to investigate the potential effect of miR-1294 in gastric cancer (GC).

METHODS

Reverse transcription quantitative polymerase chain reaction (RT-PCR) were performed to verify the expression level of miR-1294 and Forkhead box protein K1 (FOXK1). Overall survival data of miR-1294 for GC was analysed by log-rank test. Targetscan was used to screen potential target gene of miR-1294. Dual luciferase assay was assessed to investigate the relationship between miR-1294 and FOXK1. The miR-1294 overexpression and knockdown were designed to study the biological function of miR-1294. The migration and invasion of GC cell lines were investigated by wound healing and transwell assays. Western blotting were performed to verify the expression level of epithelial marker, mesenchymal markers and FOXK1. Overexpression of FOXK1 was designed to study the rescue effects of FOXK1 in SGC7901 cell.

RESULTS

miR-1294 was found downregulated in GC patients and cell lines. A higher miR-1294 expression showed a significant longer overall survival than those with a lower miR-1294 expression. miR-1294 directly targets FOXK1 and regulates the expression of FOXK1. In addition, miR-1294 regulates epithelial-mesenchymal transition (EMT) by inhibiting FOXK1 in GC cells and it can be rescued by overexpression of FOXK1.

CONCLUSION

miR-1294 alleviates EMT process in GC by targeting FOXK1.

MiR-1236-3p serves as a new diagnostic and prognostic biomarker for gastric cancer

BACKGROUND

The microRNA plays an important role in tumor progression. MiR-1236-3p acts as a tumor suppressor in various malignancies.

OBJECTIVE

The aim of present study was to explore the expression of miR-1236-3p in gastric cancer (GC) and its correlation with clinicopathological features, and evaluate the feasibility of using it as a prognostic biomarker in GC.

METHODS

Seventy-six pairs of tissue specimens were collected from GC patients. MiR-1236-3p expression level was detected by using qRT-PCR. The diagnostic value of miR-1236-3p was evaluated by receiver operating characteristic curve, and Kaplan-Meier method was used to analyze the overall survival. Prognosis analysis was performed using multivariate cox proportional hazards regression analysis.

RESULTS

The expression of miR-1236-3p was significantly reduced in tumor tissues (P< 0.001). In addition, miR-1236-3p expression was correlated with TNM stage (P= 0.001), lymph node metastasis (P= 0.005) and differentiated degree (P= 0.001). The area under the curve was 0.7016, and its specificity and sensitivity were 60.53% and 73.68%. Kaplan-Meier survival curves showed that patients with high miR-1236-3p expression had better overall survival than those with low expression (P= 0.0190). Multivariate Cox regression analysis showed that the miR-1236-3p expression (P= 0.033) was an independent prognostic factor for overall survival of GC prognosis.

CONCLUSIONS

The study showed that miR-1236-3p is downregulated in GC tissues, and low expression of miR-1236-3p is associated with a poor prognosis in GC. It may be a new diagnostic and prognostic biomarker for GC.

MicroRNA-1269 promotes cell proliferation via the AKT signaling pathway by targeting RASSF9 in human gastric cancer

Background

MicroRNAs (miRNAs) play key roles in tumorigenesis and progression of gastric cancer (GC). miR-1269 has been reported to be upregulated in several cancers and plays a crucial role in carcinogenesis and cancer progression. However, the biological function of miR-1269 in human GC and its mechanism remain unclear and need to be further elucidated.

Methods

The expression of miR-1269 in GC tissues and cell lines was detected by quantitative real-time PCR (qRT-PCR). Target prediction programs (TargetScanHuman 7.2 and miRBase) and a dual-luciferase reporter assay were used to confirm that Ras-association domain family 9 (RASSF9) is a target gene of miR-1269. The expression of RASSF9 was measured by qRT-PCR and Western blotting in GC tissues. MTT and cell counting assays were used to explore the effect of miR-1269 on GC cell proliferation. The cell cycle and apoptosis were measured by flow cytometry. RASSF9 knockdown and overexpression were used to further verify the function of the target gene.

Results

We found that miR-1269 expression was upregulated in human GC tissues and cell lines. The overexpression of miR-1269 promoted GC cell proliferation and cell cycle G1-S transition and suppressed apoptosis. The inhibition of miR-1269 inhibited cell growth and G1-S transition and induced apoptosis. miR-1269 expression was inversely correlated with RASSF9 expression in GC tissues. RASSF9 was verified to be a direct target of miR-1269 by using a luciferase reporter assay. The overexpression of miR-1269 decreased RASSF9 expression at both the mRNA and protein levels, and the inhibition of miR-1269 increased RASSF9 expression. Importantly, silencing RASSF9 resulted in the same biological effects in GC cells as those induced by overexpression of miR-1269. Overexpression of RASSF9 reversed the effects of miR-1269 overexpression on GC cells. Both miR-1269 overexpression and RASSF9 silencing activated the AKT signaling pathway, which modulated cell cycle regulators (Cyclin D1 and CDK2). In contrast, inhibition of miR-1269 and RASSF9 overexpression inhibited the AKT signaling pathway. Moreover, miR-1269 and RASSF9 also regulated the Bax/Bcl-2 signaling pathway.

Conclusions

Our results demonstrate that miR-1269 promotes GC cell proliferation and cell cycle G1-S transition by activating the AKT signaling pathway and inhibiting cell apoptosis via regulation of the Bax/Bcl-2 signaling pathway by targeting RASSF9. Our findings indicate an oncogenic role of miR-1269 in GC pathogenesis and the potential use of miR-1269 in GC therapy.

lncRNA HOTAIR promotes gastric cancer proliferation and metastasis via targeting miR-126 to active CXCR4 and RhoA signaling pathway

HOTAIR, a well-known long noncoding RNAs (lncRNA), has been recognized to contribute to the tumor metastasis in several tumors. But its role in gastric cancer remains elusive. Here, we reported an increase in HOTAIR promoted proliferation and metastasis of gastric cancer cell lines. The HOTAIR and miR-126 level was determined in 15 paired primary gastric cancer tissues and their adjacent noncancerous gastric tissues. Over-expression or downregulation HOTAIR was conducted in AGS or BGC-823 cells to investigate the impact of HOTAIR in proliferation and metastasis. Then dual luciferase reporter assay was utilized to study the interaction between CXCR4 and miR-126. Cells transfected with shHOTAIR or miR-126 mimic were subjected to western blot to investigate the role of SDF-1/CXCR4 signaling in HOTAIR mediated proliferation and metastasis. HOTAIR was highly expressed in gastric cancer tissues and several gastric cancer cell lines. Overexpressed HOTAIR facilitated proliferation and metastasis in vitro while HOTAIR knockdown inhibit proliferation and metastasis. A negative correlation was observed between miR-126 and HOTAIR. And, we also confirmed the decrease in miR-126 in clinic specimen. Furthermore, HOTAIR and miR-126 negatively regulated each other and then increase or decrease CXCR4 expression and downstream pathway, respectively. CXCR4 was confirmed as a direct target of miR-126. Our study demonstrated that high HOTAIR expression promote proliferation and metastasis in gastric cancer via miR-126/CXCR4 axis and downstream signaling pathways.

The efficacy and feasibility of adopting intravenous chemotherapy and oral S-1 as a sequential therapy for postoperative gastric cancer patients

Some postoperative gastric cancer patients have to terminate systemic intravenous chemotherapy early due to adverse drug reactions. We performed a retrospective study to explore the efficacy and feasibility of sequential therapy.We retrospectively analyzed 55 postoperative gastric cancer patients (Group A) who received sequential therapy (intravenous chemotherapy and S-1) and 53 patients (Group B) who received intravenous chemotherapy from January 2012 to December 2013 in our hospital. The therapeutic effect (including 1-year, 5-year tumor recurrence and survival rate) and the incidence of adverse reactions were analyzed.When death and survival for more than 5 years was regarded as the end point of follow-up, the mean follow-up period was 40.6 months (34.7-46.4) in Group A and 39.2 months (33.0-45.3) in Group B. The 1-year tumor recurrence after the operation was 23.6% (13/55, Group A) and 28.3% (15/53, Group B). The 5-year tumor recurrence was 45.5% (25/55, Group A) and 49.1% (26/53, Group B). There was no significant difference in the 1- and 5-year tumor recurrence rates between these two groups (P > .05). The 1-year survival rates of Group A and Group B were 81.8% (45/55) and 79.2% (42/53), respectively, and the 5-year survival rates of Group A and Group B were 47.3% (26/55) and 45.3% (24/53), respectively. No significant difference was observed between these two treatments at either the 1- or 5-year survival benefit (P > .05). However, the patients in Group A had a lower incidence of gastrointestinal reactions (such as nausea and vomiting), leukopenia and liver function damage (P < .05). We also found that patients who underwent sequential therapy might show lower levels of adverse reactions.Our retrospective study provided some evidence to suggest that sequential treatment is effective and safe for postoperative gastric cancer patients who are intolerant to intravenous chemotherapy.

Lysyl oxidase promotes liver metastasis of gastric cancer via facilitating the reciprocal interactions between tumor cells and cancer associated fibroblasts

Background

Liver is one of the most preferred destinations of distant metastasis in gastric cancer (GC). As effective treatment is still limited, the prognosis of GC patients bearing liver metastasis is poor. We filter out lysyl oxidase (LOX) to study its function in the tumor microenvironment (TME) and seek for potential therapeutic targets.

Methods

Transcription analysis on 6 cases of liver metastasis of GC patients with respective paired primary tumors and adjacent normal livers was performed. The filtration out of LOX was done using 5 datasets. 69 GC liver metastasis tissues were utilized to perform immunohistochemistry (IHC) and analyze prognosis. Computed Tomography (CT) combined 3D organ reconstruction bioluminescence imaging was performed to precisely evaluate the metastatic tumor burden on liver of intrasplenic injection mouse model. Human and mouse cancer associated fibroblasts (CAFs) in liver metastasis were separated to culture to study the interaction of LOX and TGF-β1. Patients-derived xenograft (PDX) model was established using liver metastasis of patients to evaluate the therapeutic value of LOX inhibitor β‐aminopropionitrile (BAPN).

Results

CAFs-derived LOX at liver metastatic niche of GC promotes niche formation and outgrowth thus predicts poor prognosis. Meanwhile tumor cells in niche secrete TGF-β1 to nourish CAFs and stimulate them to produce more LOX in turn. The mechanism involved in LOX-mediated proliferation facilitation is enhancement of Warburg effect. The inhibitor of LOX, BPAN could hamper the effect brought by LOX in vivo and in vitro.

Interpretation

Our study has unveiled a positive feedback loop between CAFs and tumor cells in liver metastasis niche of GC. The core molecule is LOX which facilitates Warburg effect. Targeting LOX with its inhibitor BAPN might serve as a potential therapeutic strategy.

Fund

This research was supported by the National Natural Science Foundation of China (31872740), the 100-member plan of the Shanghai Municipal Commission of Health and Family Planning (2017BR043), Shanghai Science and Technology Commission Project(17ZR1416800), Renji Hospital Training Fund (PYMDT-003, PYIII-17–015), National Natural Science Foundation of China (81672358), the Shanghai Municipal Education Commission—Gao feng Clinical MedicineGrant Support (20181708), Program of Shanghai Academic/Technology Research Leader(19XD1403400), Science and Technology Commission of Shanghai Municipality (18410721000), Shanghai Municipal Health Bureau (2018BR32), China Postdoctoral Science Foundation (2018M640403), National Natural Science Foundation of China (81701945) and Youth project of Shanghai Municipal Health Commission(20164Y0045).

GLI1 activation by non-classical pathway integrin αvβ3/ERK1/2 maintains stem cell-like phenotype of multicellular aggregates in gastric cancer peritoneal metastasis

Peritoneal metastasis is one of the most important causes of postoperative death in patients with gastric cancer, and the exact mechanism remains unclear. The proliferation of multicellular aggregates of exfoliated malignant gastric cells in the abdominal cavity is the focus of current research. However, the mechanism how gastric cancer multicellular aggregates survive remains unclear. In this study, we demonstrated that multicellular aggregates of exfoliated gastric cancer cells in the abdominal cavity expressed a stem cell-Like phenotype. We found that Integrin α_vβ₃ not only mediated adhesion of gastric cancer multicellular aggregates to form independent functional units, but also maintained their stem cell-like phenotype by the non-classical pathway Integrin α_vβ₃/ERK1/2/GLI1. In addition, ERK1/2 directly regulates the transcriptional activity of GLI1. GLI1 is a key effector of the Integrin α_vβ₃ pathway in regulating stem cell-like phenotype in multicellular aggregates. Our data indicates that although there is a crosstalk between the non-classical Integrin α_vβ₃ pathway and the classical Hedgehog pathway, the activation of GLI1 is almost independent of the Hedgehog pathway in multicellular aggregates of gastric cancer cells. Our study provides a basis for blocking GLI1 activity in the prevention and treatment of peritoneal metastases of gastric cancer.

Adenosine interaction with adenosine receptor A2a promotes gastric cancer metastasis by enhancing PI3K-AKT-mTOR signaling

The accumulation of adenosine in the tumor microenvironment is associated with tumor progression in many cancers. However, whether adenosine is involved in gastric cancer (GC) metastasis and progression, and the underlying molecular mechanism, is largely unclear. In this study, we find that GC tissues and cell lines had higher A2aR levels than nontumor gastric tissues and cell lines. A2aR expression correlated positively with TNMstage, and associated with poor outcomes. Adenosine enhanced the expression of the stemness and epithelial-mesenchymal transition-associated genes by binding to A2aR. A2aR expression on GC cells promoted metastasis in vivo. The PI3K-AKT-mTOR signaling pathway was involved in adenosine-stimulated GC cell migration and invasion. Our results indicate that adenosine promotes GC cell invasion and metastasis by interacting with A2aR to enhance PI3K-AKT-mTOR pathway signaling.

Application of Big Data analysis in gastrointestinal research

Big Data, which are characterized by certain unique traits like volume, velocity and value, have revolutionized the research of multiple fields including medicine. Big Data in health care are defined as large datasets that are collected routinely or automatically, and stored electronically. With the rapidly expanding volume of health data collection, it is envisioned that the Big Data approach can improve not only individual health, but also the performance of health care systems. The application of Big Data analysis in the field of gastroenterology and hepatology research has also opened new research approaches. While it retains most of the advantages and avoids some of the disadvantages of traditional observational studies (case-control and prospective cohort studies), it allows for phenomapping of disease heterogeneity, enhancement of drug safety, as well as development of precision medicine, prediction models and personalized treatment. Unlike randomized controlled trials, it reflects the real-world situation and studies patients who are often under-represented in randomized controlled trials. However, residual and/or unmeasured confounding remains a major concern, which requires meticulous study design and various statistical adjustment methods. Other potential drawbacks include data validity, missing data, incomplete data capture due to the unavailability of diagnosis codes for certain clinical situations, and individual privacy. With continuous technological advances, some of the current limitations with Big Data may be further minimized. This review will illustrate the use of Big Data research on gastrointestinal and liver diseases using recently published examples.

Clinicopathological, immune and molecular correlates of PD-L2 methylation in gastric adenocarcinomas

Aim: We investigated the significance of PD-L2 DNA methylation in gastric adenocarcinomas. Methods: We analyzed the methylation at different CpG sites within the PD-L2-encoding gene PDCD1LG2 with regard to correlations and associations with gene expression, clinicopathological parameters, molecular features and immune cell infiltrates in two publicly available cohorts (The Cancer Genome Atlas and Singapore cohorts) of a total of 594 gastric adenocarcinoma patients. Results: PD-L2 methylation is significantly associated with transcriptional activity, survival, Epstein–Barr virus infection, PD-L2 gene amplification, CD8+ T-cell infiltration, microsatellite instability and high mutational load (tumor mutational burden, hypermutation). Conclusion: PD-L2 methylation is associated with known predictive biomarkers of response to anti-PD-1 immunotherapies.

NPTX1 promotes metastasis via integrin/FAK signaling in gastric cancer

PURPOSE

This study aimed to investigate the effect of NPTX1 on the prognosis of gastric cancer (GC), as well as the metastatic process in GC.

MATERIALS AND METHODS

The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases were used to analyze the association between NPTX1 expression and prognosis in GC. Quantitative real-time polymerase chain reaction and Western blots were applied to examine the expression of NPTX1 in GC cell lines and expression of genes in downstream pathways. The role of NPTX1 on the migration, invasion, adhesion, and proliferation of GC cell lines was investigated with the transwell assay, the adhesion assay, and the MTT assay. Immunofluorescence staining was used to observe the effect of NPTX1 knockdown on the morphology of cells.

RESULTS

According to the review of TCGA and GEO databases of GC, we found that the expression of NPTX1 increased in cancer tissues and high NPTX1 expression was correlated with poor overall survival, which was associated with lymph node stage in clinicopathologic parameters. Knockdown of NPTX1 attenuated the migration, invasion, and adhesion abilities of GC cells. According to gene set enrichment analysis, NPTX1 was found to be positively related to integrin and focal adhesion (FA). Additionally, NPTX1 knockdown decreased the expression of integrin α1 and integrin α7, followed by deregulation of the expression of p-Src, p-Akt, p-Erk, MMP2, and MMP7, as well as inhibiting the formation of FA complexes and decreasing the length of pseudopods in GC cells.

CONCLUSION

Our study provides strong evidence that NPTX1 plays a crucial role in promoting metastasis and acts as a prognostic indicator in GC.