Molecular Characterization of Gastric Carcinoma: Therapeutic Implications for Biomarkers and Targets

The Growth Modulation Index (GMI) as an Efficacy Outcome in Cancer Clinical Trials: A Scoping Review with Suggested Reporting Guidelines

PURPOSE OF REVIEW

The growth modulation index (GMI) is defined as the ratio between the time to progression of a new line of treatment and the previous line. This ratio can be used to determine whether the new line of treatment brings a clinical benefit. It has been proposed as an outcome in trials evaluating non-cytotoxic drugs. Its interest lies in the intra-patient comparison. The terminology employed to refer to the GMI, as well as its definitions, are highly variable in the literature. Some uses of the GMI are arbitrary and not based on any scientific rationale. Our aim is to describe how the GMI is reported in the scientific literature.

RECENT FINDINGS

We carried out a scoping review using PubMed, Scopus, Web of Science and BASE (Bielefeld Academic Search Engine). The algorithm was composed of the terms "growth modulation index", "time to progression ratio" and "progression-free survival ratio". Documents in English, with full-text available, published up to 2023, were included. Among 227 included documents, 166 of which discussed GMI specifically. On these 166 documents, 76 reported on observational studies, 62 on interventional studies and 17 on methodological or statistical developments pertaining to the GMI. All were about oncology. Our review highlights significant variability in the reporting and use of the GMI. To address this, we propose standardized reporting guidelines. Additionally, we emphasize the need for methodological and statistical developments to improve the use of the GMI and to develop novel GMI-based trial designs.

Effect of Minimally Invasive versus Open Distal Gastrectomy on Long-Term Survival in Patients with Gastric Cancer: Individual Patient Data Meta-analysis

BACKGROUND

Minimally invasive distal gastrectomy (MIDG) has been shown to improve short-term outcomes compared with open distal gastrectomy (ODG) in patients with early (EGC) and locally advanced gastric cancer (LAGC). The impact of MIDG on patient survival remains debated. This study aimed to compare the effect of MIDG versus ODG on long-term survival.

PATIENTS AND METHODS

Randomized clinical trial (RCTs) individual patient data (IPD) meta-analysis with restricted mean survival time difference (RMSTD) estimation. Scopus, MEDLINE, Web of Science, and ClinicalTrials.gov were searched. Primary outcomes were 5-year overall (OS), disease free survival (DFS), and cancer specific survival (CSS). RMSTD and 95% confidence intervals (CI) were used as pooled effect size measures. The certainty of evidence was categorized with the Grading of Recommendations, Assessment, Development, and Evaluation framework.

RESULTS

Overall, ten RCTs (5297 patients) were included; 50.4% of patients underwent MIDG. At 60-months follow-up, the OS and DFS estimates for ODG versus MIDG were 0.41 months (95% CI - 0.17, 0.99; high level of certainty) and 0.42 months (95% CI - 0.38, 1.23; high level of certainty). CSS was specified in two RCTs, hence quantitative analysis was not practicable. The 60-month OS and DFS estimates for LAGC (five studies) were 0.32 months (95% CI - 0.80, 1.44; high level of certainty) and 0.31 months (95% CI - 2.02, 1.33; high level of certainty), respectively. The 36-month DFS appraisal for stage III patients (three studies) was - 0.41 months (95% CI - 26.1, 38.2; low level of certainty).

CONCLUSIONS

This meta-analysis found high-certainty evidence that MIDG and ODG demonstrate similar 5-year OS and DFS in patients with both EGC and LAGC.

Minimally Invasive Versus Open Distal Gastrectomy for Locally Advanced Gastric Cancer: Trial Sequential Analysis of Randomized Trials

BACKGROUND

Minimally invasive distal gastrectomy (MIDG) has been shown to be associated with improved short-term outcomes compared to open distal gastrectomy (ODG) in patients with locally advanced gastric cancer (LAGC). The impact of MIDG on long-term patient survival remains debated. Aim was to compare the MIDG vs. ODG effect on long-term survival.

METHODS

Systematic review and trial sequential analysis (TSA) of randomized controlled trials (RCTs). Web of Science, Scopus, MEDLINE, the Cochrane Central Library, and ClinicalTrials.gov were queried. Hazard ratio (HR) and 95% confidence intervals (CI) were used as pooled effect size measures. Five-year overall (OS) and disease-free survival (DFS) were primary outcomes.

RESULTS

Five RCTs were included (2835 patients). Overall, 1421 (50.1%) patients underwent MIDG and 1414 (49.9%) ODG. The ages ranged from 48 to 70 years and 63.4% were males. The pooled 5-year OS (HR = 0.86; 95% CI 0.70-1.04; I2 = 0.0%) and 5-year DFS (HR = 1.03; 95% CI 0.87-1.23; I2 = 0.0%) were similar for MIDG vs. ODG. The TSA shows a cumulative z-curve without crossing the monitoring boundaries line (Z = 1.96), thus suggesting not conclusive 5-year OS and DFS results because the total information size was not sufficient.

CONCLUSIONS

MIDG and ODG seem to have equivalent 5-year OS and DFS in patients with LAGC. However, the cumulative evidence derived from the TSA showed that the actual information size is not sufficient to provide conclusive data.

System analysis based on T-cell exhaustion-related genes identifies PTPRT as a promising diagnostic and prognostic biomarker for gastric cancer

Multiple investigations have demonstrated the crucial involvement of T-cell exhaustion (TEX) in anti-tumor immune response and their strong correlation with prognosis. This study aimed at creating a strong signature using TEX for gastric cancer through bioinformatics analysis and experimental validation. We utilized data from The Cancer Genome Atlas (TCGA) databases to retrieve RNA-seq data from patients with stomach adenocarcinoma (STAD). Genes related to TEX were discovered using gene set variance analysis (GSVA) and weighted gene correlation network analysis (WGCNA). Subsequently, prognostic signature based on TEX was developed using LASSO-Cox analysis. Relationship between key genes and immune cells were examined. Finally, biological function of a key TEX-related gene PTPRT in gastric cancer was verified by in vivo experiment. A total of 29 TEX-related biomarkers were screened by WGCNA and random forest. Among them, five core signatures (PTPRT, CAV2, PPIH, PRDM2, and FGF1), further identified by LASSO-Cox, were considered as strong predictors of prognosis for gastric cancer and associated with immune infiltration. PTPRT gene had the largest number of SNPs, with the most mutation types. In vivo experiments revealed that PTPRT overexpression significantly inhibited tumor malignant progression and accelerated apoptosis through stimulating the secretion of killer cytokines such as TNF-α and IFN-γ. In addition, flow cytometry revealed that PTPRT overexpression alleviated TEX by increasing the abundance of CD8+ T cells, with inhibition of cell surface PD-1 and Tim-3. The predictive prognostic value of TEX gene expression levels was evaluated in patients with gastric cancer, providing a new perspective for precision immuno-oncology studies.

A tumor microenvironment-based classification of gastric cancer for more effective diagnosis and treatment

With approximately one million diagnosed cases and over 700,000 deaths recorded annually, gastric cancer (GC) is the third most common cause of cancer-related deaths worldwide. GC is a heterogeneous tumor. Thus, optimal management requires biomarkers of prognosis, treatment selection, and treatment response. The Cancer Genome Atlas program sub-classified GC into molecular subtypes, providing a framework for treatment personalization using traditional chemotherapies or biologics. Here, we report a comprehensive study of GC vascular and immune tumor microenvironment (TME)-based on stage and molecular subtypes of the disease and their correlation with outcomes. Using tissues and blood circulating biomarkers and a molecular classification, we identified cancer cell and tumor archetypes, which show that the TME evolves with the disease stage and is a major determinant of prognosis. Moreover, our TME-based subtyping strategy allowed the identification of archetype-specific prognostic biomarkers such as CDH1-mutant GC and circulating IL-6 that provided information beyond and independent of TMN staging, MSI status, and consensus molecular subtyping. The results show that integrating molecular subtyping with TME-specific biomarkers could contribute to improved patient prognostication and may provide a basis for treatment stratification, including for contemporary anti-angiogenesis and immunotherapy approaches.

Comprehensive bioinformatic analysis of mind bomb 1 gene in stomach adenocarcinoma

BACKGROUND

The carcinogenesis of stomach adenocarcinoma (STAD) involves many different molecules and multiple pathways, including the NOTCH signaling pathway. As a key factor that functions as a critical link in the NOTCH pathway, mind bomb 1 (MIB1) is upregulated in various tumors and has been reported to promote cell metastasis and invasion. However, studies on the role of MIB1 in STAD are limited. Here, we evaluated the prognostic value of MIB1 in STAD and its association with immune infiltration and copy number variation.

AIM

To elucidate the relationship between MIB1 gene and gastric cancer (GC) and provide a new idea for the treatment of GC.

METHODS

We identified mutations in the MIB1 gene by searching the cBioPortal database and then analyzed their relationship with the overall survival rate and disease-free survival rate using the Kaplan-Meier method. The Cancer Genome Atlas (TCGA) database provided transcript levels for MIB1 in STADs and normal tissues. As a method of distinguishing the STAD tissues from adjacent normal tissues, a receiver operating characteristic (ROC) curve was generated. Kaplan-Meier plotter was used to determine the effect of MIB1 expression on survival. Based on the LinkedOmics database, we were able to identify the coexpressed genes of the MIB1 gene, the top 50 positively correlated genes, and the top 50 negatively correlated genes. STRING was used to construct protein-protein interaction networks related to the MIB1 gene. An analysis of functional enrichment was carried out using the R package “Cluster Profiler”. The relationships between mRNA expression of MIB1 and immune infiltrates were assessed by Tumor IMmune Estimation Resource (TIMER) and the “GSVA package” in R.

RESULTS

According to the cBioPortal database, the MIB1 mutation rate in 287 patients in the TCGA dataset was approximately 6%. Kaplan-Meier survival analysis showed that patients with STAD in the mutated group had a worse prognosis than those in the unmutated group (P = 0.0156). There was a significant upregulation of MIB1 expression in STAD tissues compared to adjacent normal tissues. A high T stage was associated with increased MIB1 mRNA expression. The ROC curve analysis revealed 59.4% sensitivity and 85.6% specificity of MIB1 for differentiating STAD tissues from adjacent normal tissues at a truncation level of 2.248. Kaplan-Meier plotter indicated that patients with higher MIB1 levels had a worse prognosis than those with lower levels (26.4 mo vs 56.2 mo, P = 0.0330). A correlation analysis demonstrated an association between immune infiltrates and MIB1 mRNA expression.

CONCLUSION

Upregulation of MIB1 expression is significantly associated with poor survival rate and immune infiltration in gastric adenocarcinoma. MIB1 may be a biomarker for the poor prognosis of STAD patients and a potential immunotherapeutic target.

Safety and effectiveness of apatinib in elderly patients with metastatic gastric cancer: a sub-analysis from the large-scale, prospective observational study of apatinib for gastric cancer treatment in a real-world clinical setting (AHEAD-G202)

Background

Apatinib was shown to improve the survival of Chinese patients with refractory metastatic gastric cancer (mGC). As an orally administered drug, it has been widely used in elderly patients because the dosing schedule can be adjusted flexibly. However, data on the efficacy and safety of apatinib in elderly patients is scarce. The aim of this study was to evaluate the toxicity and effectiveness of apatinib for elderly patients with mGC in a real-world setting.

Methods

Data from the sub-population of patients who were ≥65 years enrolled in the AHEAD-G202 trial were analyzed. Patients with mGC were prospectively registered and initially received ≤850 mg oral apatinib daily combined or not combined with chemotherapy, at the investigator's discretion. The primary endpoint was safety. The secondary endpoints were overall survival (OS) and progression-free survival (PFS).

Results

A total of 117 patients were included. There were 51 (43.59%) patients in the low-dose (250 mg) group, 60 (51.28%) patients in the mid-dose (425 to 500 mg) group, and 6 (5.13%) patients in the high-dose (850 mg) group according to the initial daily doses. Hypertension (6.84%) was the only grade 3-4 adverse event (AE) with a prevalence of more than 5% and across the low-dose (11.76%), mid-dose (3.33%) and high-dose group (0%). The median OS and PFS were 7.13 months (95% CI: 5.04 to 9.22 months) and 4.27 months (95% CI: 3.24 to 5.29 months), respectively. The OS and PFS were similar among the 65-74 and ≥75 years groups (χ2=1.406, P=0.306; χ2=0.378, P=0.066, respectively). The OS and PFS were also comparable among the 3 dose groups.

Conclusions

Elderly patients with mGC can tolerate and benefit from apatinib therapy. A lower initial daily dosing strategy may be a suitable choice for elderly patients in clinical practice.

Deep Learning-Based Protein Features Predict Overall Survival and Chemotherapy Benefit in Gastric Cancer

Gastric cancer (GC) is one of the most common malignant tumors with a high mortality rate worldwide and lacks effective methods for prognosis prediction. Postoperative adjuvant chemotherapy is the first-line treatment for advanced gastric cancer, but only a subgroup of patients benefits from it. Here, we used 833 formalin-fixed, paraffin-embedded resected tumor samples from patients with TNM stage II/III GC and established a proteomic subtyping workflow using 100 deep-learned features. Two proteomic subtypes (S-I and S-II) with overall survival differences were identified. S-I has a better survival rate and is sensitive to chemotherapy. Patients in the S-I who received adjuvant chemotherapy had a significant improvement in the 5-year overall survival rate compared with patients who received surgery alone (65.3% vs 52.6%; log-rank P = 0.014), but no improvement was observed in the S-II (54% vs 51%; log-rank P = 0.96). These results were verified in an independent validation set. Furthermore, we also evaluated the superiority and scalability of the deep learning-based workflow in cancer molecular subtyping, exhibiting its great utility and potential in prognosis prediction and therapeutic decision-making.

Development and Validation of a Three-Gene Prognostic Signature Based on Tumor Microenvironment for Gastric Cancer

Gastric cancer (GC), which has high morbidity and low survival rate, is one of the most common malignant tumors in the world. The increasing evidences show that the tumor microenvironment (TME) is related to the occurrence and progression of tumors and the prognosis of patients. In this study, we aimed to develop a TME-based prognostic signature for GC. We first identified the differentially expressed genes (DEGs) related to the TME using the Wilcoxon rank-sum test in a training set of GC. Univariate Cox regression analysis was used to identify prognostic-related DEGs. To decrease the overfitting, we performed the least absolute shrinkage and selection operator (LASSO) regression to reduce the number of signature genes and obtained three genes (LPPR4, ADAM12, NOX4). Next, the multivariate Cox regression was performed to construct the risk score model, and a three-gene prognostic signature was developed. According to the signature, patients were classified into high-risk and low-risk groups with significantly different survival. The signature was then applied to three independent validated sets and obtained the same results. We conducted the time-dependent Receiver Operating Characteristic (ROC) curve analysis to evaluate our signature. We further evaluated the differential immune characters between high-risk and low-risk patients to reveal the potential immune mechanism of the impact on the prognosis of the model. Overall, we identified a three-gene prognostic signature based on TME to predict the prognosis of patients with GC and facilitate the development of a precise treatment strategy.

CircTMC5 promotes gastric cancer progression and metastasis by targeting miR-361-3p/RABL6

BACKGROUND

Gastric cancer (GC) is common in East Asia, yet its molecular and pathogenic mechanisms remain unclear. Circular RNAs (circRNAs) are differentially expressed in GC and may be promising biomarkers. Here, we investigated the role and regulatory mechanism of circTMC5 in GC.

METHODS

CircTMC5 expression was detected in human GC and adjacent tissues using microarray assays and qRT-PCR, while the clinicopathological characteristics of patients with GC were used to assess its diagnostic and prognostic value. The circTMC5/miR-361-3p/RABL6 axis was examined in vitro and vivo, and the immune roles of RABL6 were evaluated using bioinformatics analyses and immunohistochemistry (IHC).

RESULTS

CircTMC5 was highly expressed in GC tissues, plasma, and cell lines, and was closely related to histological grade, pathological stage, and T classification in patients with GC. CircTMC5 expression was also an independent prognostic factor for GC and its combined detection with carcinoembryonic antigen may improve GC diagnosis. Low circTMC5 expression correlated with good prognosis, inhibited GC cell proliferation, and promoted apoptosis. Mechanistically, circTMC5 overexpression promoted GC cell proliferation, invasion, and metastasis but inhibited apoptosis by sponging miR-361-3p and up-regulating RABL6 in vitro and vivo, whereas miR-361-3p up-regulation had the opposite effects. RABL6 was highly expressed in GC and was involved in immune regulation and infiltration in GC.

CONCLUSIONS

CircTMC5 promotes GC and sponges miR-361-3p to up-regulate RABL6 expression, thus may have diagnostic and prognostic value in GC. RABL6 also displays therapeutic promise due to its role in the immune regulation of GC.

A Comprehensive Bioinformatic Analysis of NOTCH Pathway Involvement in Stomach Adenocarcinoma

Background

Activation of NOTCH signaling pathways, which are key regulators of multiple cellular functions, has been frequently implicated in cancer pathogenesis, and NOTCH inhibitors have received much recent focus in the context of cancer therapeutics. However, the role and possible involvement of NOTCH pathways in stomach adenocarcinoma (STAD) are unclear. Here, putative regulatory mechanisms and functions of NOTCH pathways in STAD were investigated.

Methods

Publicly available data from the TCGA-STAD database were utilized to explore the involvement of canonical NOTCH pathways in STAD by analyzing RNA expression levels of NOTCH receptors, ligands, and downstream genes. Statistical analysis of the data pertaining to cancer and noncancerous samples was performed using R software packages and public databases/webservers.

Results

Significant differential gene expression between control and STAD samples was noted for all NOTCH receptors (NOTCH1, 2, 3, and 4), the delta-like NOTCH ligands (DLL-3 and 4), and typical downstream genes (HES1 and HEY1). Four genes (NOTCH1, NOTCH2, NOTCH3, and HEY1) presented prognostic values for the STAD outcome in terms of overall survival. Functional enrichment analysis indicated that NOTCH family genes-strongly correlated genes were mainly enriched in several KEGG signaling pathways such as the PI3K-Akt signaling pathway, human papillomavirus infection, focal adhesion, Rap1 signaling pathway, and ECM-receptor interaction. Gene set enrichment analysis (GSEA) results showed that NOTCH family genes-significantly correlated genes were mainly enriched in four signaling pathways, ECM (extracellular matrix), tumor angiogenesis, inflammatory response, and immune regulation.

Conclusions

NOTCH family genes may play an essential role in the progression of STAD by modulating immune cells and mediating ECM synthesis, angiogenesis, focal adhesion, and PI3K-Akt signaling. Multiple NOTCH family genes are valuable candidate biomarkers or therapeutic targets for the management of STAD.

Immunotherapy Efficacy in the Initial Lines of Treatment in Advanced Upper Gastrointestinal Malignancies: A Systematic Review of the Literature

Background

The therapeutic role of immune checkpoint inhibitors (ICIs) has represented the cutting edge of clinical research in upper gastrointestinal (GI) malignancies, with these agents now included in the armamentarium of treatment options for advanced gastric and esophageal cancers.

Methods

We performed a systematic literature review and pooled analysis to map out the currently available robust clinical evidence for the use of ICIs in upper GI cancers. Immunotherapy (IO), either as monotherapy or in combination with chemotherapy, and its role in first-line, maintenance, and second-line settings, as well as in specific clinical and biological subgroups, were critically appraised. All statistical tests were 2-sided.

Results

ICIs, in combination with chemotherapy, have provided statistically significant overall survival benefit in the first-line setting in gastric and gastro-esophageal adenocarcinomas (hazard ratio [HR] = 0.83, 95% confidence interval [CI] = 0.76 to 0.90, P < .001; based on 4 studies) and esophageal squamous cell carcinoma (HR = 0.72, 95% CI = 0.64 to 0.81, P < .001; based on 3 studies), albeit with heterogeneous efficacy according to biomarker expression. Patients with esophageal squamous cell carcinoma, and in particular high programmed cell death ligand-1 expression, derive survival benefit when treated with IO in the second-line setting (HR = 0.74, 95% CI = 0.68 to 0.82, P < .001; for any level of programmed cell death ligand-1 expression). Clinical trials interrogating the combination of IO with chemotherapy in second-line treatment should be seriously considered in upper GI adenocarcinomas. The role of maintenance IO after initial disease control is still unclear and cannot be recommended. Impressive response rates and survival benefit from IO have been reported in patients with microsatellite instability-high tumors (HR = 0.33, 95% CI = 0.19 to 0.57, P < .001), and this warrants further prospective biomarker-driven studies.

Conclusions

IO is changing the treatment landscape in upper GI malignancies. The rapidly developing evidence in the field needs to be critically appraised while further validation of the existing information from ongoing trials is awaited.

Her2-Positive and Microsatellite Instability Status in Gastric Cancer-Clinicopathological Implications

Gastric cancer (GC) is one of the leading causes of cancer-related death. The combination of new molecular classifications with clinicopathological data could contribute to the individualization of patients and to the development of new therapeutic strategies. We examined the various associations in two molecular types of GC: HER2-positive (human epidermal growth factor receptor 2) and microsatellite instability (MSI), assessing their influence on treatment and prognosis. A retrospective study of 142 GC patients was performed with molecular characterization through HER2 overexpression and DNA repair protein expression for MSI. The percentage of HER2-positive tumors was 13.4%, predominantly in men. Correlations were found with intestinal type, metastases, advanced stages and chemotherapy. Almost 75% of HER2-positive patients died. MSI occurred in 16.2%, associated with advanced age, female sex, distal location and intestinal type. These patients had few metastases and low stages. The percentage of deaths was higher among MSI patients who received perioperative chemotherapy. The determination of HER2 and MSI status in GC is important for their association with specific clinicopathological features and for their prognostic and predictive value.

Clinical Evaluation of the Safety and Efficacy of Trifluridine/Tipiracil in the Treatment of Advanced Gastric/Gastroesophageal Junction Adenocarcinoma: Evidence to Date

Trifluridine/tipiracil or TAS-102 (Taiho Oncology, Lonsurf®, Princeton, NJ, USA) is a combination tablet of trifluridine, a thymidine-based nucleoside analog, and tipiracil, a thymidine phosphorylase inhibitor, in a 1:0.5 molar ratio. This drug was first approved for use in metastatic colorectal cancer patients. Recently, the U S Food and Drug Administration (FDA) and the European Medicines Agency (EMA) have granted approval of trifluridine/tipiracil for treatment of metastatic gastric and gastroesophageal junction adenocarcinoma in patients following at least two lines of chemotherapy including fluoropyrimidine and platinum chemotherapy agents, as well as taxanes or irinotecan. This approval was granted after the findings from first a Phase II trial (EPOC1201) investigating trifluridine/tipiracil, and later a global Phase III trial (TAGS trial) that compared trifluridine/tipiracil vs placebo with best supportive care. Both trials primarily utilized trifluridine/tipiracil at a dose of 35 mg/m2 twice daily. In the EPOC1201 trial, the primary end point of disease control rate was greater than 50% after eight weeks of therapy. The most common grade three or four adverse event was neutropenia; additional toxicities included leukopenia, anemia, and anorexia. In the TAGS trial, overall survival in patients treated with trifluridine/tipiracil (5.7 months) was significantly improved as compared to the placebo-controlled group (3.6 months). Treatment with trifluridine/tipiracil not only did not impair quality of life but also tended to reduce the risk of deterioration of quality of life. The results of these studies along with the subsequent FDA and EMA approval have generated an important breakthrough in regard to treatment options for patients with refractory metastatic gastric or gastroesophageal junction adenocarcinoma.

Exploring TCGA database for identification of potential prognostic genes in stomach adenocarcinoma

Background

Stomach adenocarcinoma (STAD) is the fifth most prevalent cancer in the world and ranks third among cancer-related deaths worldwide. The tumour microenvironment (TME) plays an important role in tumorigenesis, development, and metastasis. Hence, we calculated the immune and stromal scores to find the potential prognosis-related genes in STAD using bioinformatics analysis.

Methods

The ESTIMATE algorithm was used to calculate the immune/stromal scores of the STAD samples. Functional enrichment analysis, protein–protein interaction (PPI) network analysis, and overall survival analysis were then performed on differential genes. And we validated these genes using data from the Gene Expression Omnibus database. Finally, we used the Human Protein Atlas (HPA) databases to verify these genes at the protein levels by IHC.

Results

Data analysis revealed correlation between stromal/immune scores and the TNM staging system. The top 10 core genes extracted from the PPI network, and primarily involved in immune responses, extracellular matrix, and cell adhesion. There are 31 genes have been validated with poor prognosis and 16 genes were upregulated in tumour tissues compared with normal tissues at the protein level.

Conclusions

In summary, we identified genes associated with the tumour microenvironment with prognostic implications in STAD, which may become potential therapeutic markers leading to better clinical outcomes.

The expression of epidermal growth factor receptor 1 and human epidermal growth factor receptor 2 based on tumor location affect survival in gastric cancer

To investigate the different expression of epidermal growth factor receptor 1 (EGFR) and human epidermal growth factor receptor 2 (HER2) in gastric cancer based on tumor locations and its impact on patients survival.Gastric cancer is heterogeneous disease, recent years have established a molecular classification and described distribution of molecular subtypes in stomach. However, the difference of EGFR and HER-2 expression among tumor location is still unknown.Between January 2010 and August 2014, 2477 consecutive patients with gastric cancer were treated in our surgery department. The tumor locations were classified into 4 groups: cardia, fundus, corpus, and antrum. Based on tumor locations, the clinicopathologic characteristics, EGFR and HER-2 expression, and follow-up data were analyzed by univariant analysis and Kaplan-Meier analysis retrospectively.There were difference of gender, age, Borrmann type, pathological type, differentiation, T-stage, tumor size, gastrectomy method, and complications among the locations. The positive rate of EGFR expression in fundus was 18.18%, which was lower than cardia (46.21%), corpus (43.62%), and antrum (48.83%) (P < .001). The 5-year survival rate in EGFR positive patients was 50.8%, which was significantly lower than EGFR negative patients (64.0%, P = .021). The positive rate of HER-2 expression in cardia was 48.15%, which was significantly higher than fundus (37.5%), corpus (35.45%), and antrum (38.54%) (P = .009), but HER-2 expression did not correlate with 5-year survive (P = .548).Our results suggest that there exist difference of EGFR and HER-2 expression based on tumor locations, and the distribution of EGFR impact on patients survival. Emphasizing the role of EGFR and HER-2 in the context of location contribute to make appropriate treatment strategy and improve prognosis of gastric cancer.

Reactivation of microRNA-506 inhibits gastric carcinoma cell metastasis through ZEB2

MicroRNAs (miRNAs) are frequently dysregulated in a variety of human cancers, including gastric carcinoma. To improve our understanding of the role of miRNAs in gastric carcinoma and potential identify novel biomarkers or therapeutic agents, we performed microarray analysis to identify differentially expressed miRNAs in gastric carcinoma, compared with paired non-cancerous gastric tissues. We identified significantly differentially expressed miRNAs in gastric carcinoma tissues, including miR-506. We validated the microarray results by quantitative reverse transcription polymerase chain reaction in 26 specimens and confirmed significant downregulation of miR-506 in gastric carcinoma. Bioinformatics analysis predicted ZEB2 (zinc finger E-box-binding homeobox 2) as a potential target of miR-506. MiR-506 levels and ZEB2 levels were inversely correlated in gastric carcinoma, and low miR-506 levels in gastric carcinoma were associated with poor prognosis. Overexpression of miR-506 in gastric carcinoma cells significantly inhibited cell migration and invasion, while depletion of miR-506 in gastric carcinoma cells significantly increased cell migration and invasion. Transplantation of miR-506-overexpressing gastric carcinoma cells developed significantly smaller tumor, compared to the control. Thus, our results suggest that miR-506 may function as a tumor suppressor and targets and inhibits ZEB2 in gastric carcinoma.

MSI and EBV Positive Gastric Cancer's Subgroups and Their Link With Novel Immunotherapy

Gastric cancers have been historically classified based on histomorphologic features. The Cancer Genome Atlas network reported the comprehensive identification of genetic alterations associated with gastric cancer, identifying four distinct subtypes- Epstein-Barr virus (EBV)-positive, microsatellite-unstable/instability (MSI), genomically stable and chromosomal instability. In particular, EBV-positive and MSI gastric cancers seem responsive to novel immunotherapies drugs. The aim of this review is to describe MSI and EBV positive gastric cancer's subgroups and their relationship with novel immunotherapy.

PHTF2 regulates lipids metabolism in gastric cancer

Identification of hub genes and key pathways of gastric cancer was recognized to be essential to elucidate the tumorigenesis of GC. This study was aimed to identify the differentially expressed genes (DEGs) in GC via bioinformatics methods and their related pathways involved in the pathological process of GC. Gene expression profile datasets acquired by microarray chips or RNA-seq were downloaded from GEO dataset and TCGA, and 298 differentially expressed genes was identified. The Gene Ontology (GO) and Kyoto Gene and Genomic Encyclopedia (KEGG) pathways of DEGs were then analyzed by the DAVID database to elucidate the potential molecular functions of DEGs. The protein-protein interaction (PPI) network of DEGs was further analyzed with the STRING database and PHTF2 was identified as a hub gene in the PPI network. Subsequently, PHTF2 was found to be highly expressed in different subtypes of gastric cancer tissues obtained from TCGA database or clinical patients, resulting with a poor prognosis. By GSEA, PHTF2 was found to significantly enrich the fatty acid metabolism pathway in gastric cancer. Moreover, PHTF2-regulated lipids metabolism significantly affected the tumorigenesis of GC cells. In summary, this work identified a new mechanism by which PHTF2 precipitated in the pathological process of GC by regulating cellular lipid metabolism.

HER2 Heterogeneity in Personalized Therapy of Gastro-Oesophageal Malignancies: An Overview by Different Methodologies

Human epidermal growth factor receptor-2 (HER2)-expression gastro-oesophageal adenocarcinomas (GEA) gained interest as an important target for therapy with trastuzumab. In the current review, we focused the current knowledge on HER2 status in dysplastic and neoplastic gastric conditions, analyzing the methodological procedures to identify HER2 expression/amplification, as well as the proposed scoring recommendations. One of the most relevant questions to evaluate the useful impact of HER2 status on therapeutic choice in GEAs is represented by the significant heterogeneity of HER2 protein and gene expression that may affect the targeted treatment selection. Future development of biotechnology will continue to evolve in order to offer more powerful detection systems for the assessment of HER2 status. Finally, liquid biopsy as well as mutation/amplification of several additional genes may furnish an early detection of secondary HER2 resistance mechanisms in GEAs with a better monitoring of the treatment response.

CYP2E1 changes the biological function of gastric cancer cells via the PI3K/Akt/mTOR signaling pathway

The present study investigated the role of cytochrome P450 family 2 subfamily E polypeptide 1 (CYP2E1) in the development and progression of gastric cancer (GC). The expression levels of CYP2E1 in MGC‑803 GC cells and normal GES‑1 cells were investigated via western blotting, and it was identified that the expression of CYP2E1 was different between GES‑1 and MGC‑803 cells. CYP2E1 was overexpressed in MGC‑803 cells using a lentiviral vector GV358. Cell Counting Kit‑8, flow cytometry, cell migration and Matrigel invasion assays suggested that overexpression of CYP2E1 promoted the proliferation and invasion, and inhibited the apoptosis of GC cells. The relationship between CYP2E1 expression and key signaling molecules in the PI3K/Akt/mTOR signaling pathway was assessed. Reverse transcription‑quantitative PCR analysis showed that mTOR mRNA expression was significantly increased after overexpression of CYP2E1 (P<0.05). Western blotting results showed that overexpression of CYP2E1 upregulated the expression of phosphorylated (p)‑Akt, p‑mTOR and p‑p70 ribosomal protein S6 kinase (P70S6K; Ser371) proteins (P<0.05). To further investigate the relationship between CYP2E1 and the PI3K/Akt/mTOR signaling pathway in GC cells, MGC‑803 cells were treated with the PI3K inhibitor LY294002, and changes in the expression levels of PI3K, AKT, mTOR, P70S6K and CYP2E1 were observed. The present results showed that LY294002 downregulated the expression of PI3K, CYP2E1, AKT, mTOR and P70S6K (P<0.05). Therefore, changes in the biological function of GC cells induced by CYP2E1 overexpression may be via the PI3K/Akt/mTOR signaling pathway.

Alteration and prognostic values of collagen gene expression in patients with gastric cancer under different treatments

Collagen (COL) genes participate in tumor extracellular matrix (ECM)-receptor interactions and focal adhesion pathways, which play a crucial role in tumor invasion and metastasis. The prognostic value of COL genes has been shown for several malignancies. In the present study, we analyzed multiple microarray datasets using the Oncomine database to identify alterations of COL genes in gastric cancer (GC). Gene expression levels were analyzed by quantitative real-time polymerase chain reaction (qRT-PCR) and immunohistochemistry (IHC) in GC tissues and matched adjacent tissues. The prognostic value of differentially expressed COL genes in GC was evaluated by Kaplan-Meier survival analysis based on the complete mRNA transcriptomics data from The Cancer Genome Atlas (TCGA). We found that seven COL genes (COL1A2, COL4A1, COL4A2, COL6A1, COL6A2, COL6A3, and COL11A1) were elevated in GC. Among them, stepwise multivariate Cox regression was applied, and it was determined that COL4A1 and COL4A2 were signature and independent prognostic biomarkers in GC patients with obviously different overall survival (OS). High expression of COL4A1, COL4A2, COL6A1, COL6A2, and COL6A3 was correlated with poorer prognosis of GC patients treated by surgery only, while higher expression of COL4A1 and COL11A1 correlated with poorer survival of patients treated by 5-fluorouracil-based adjuvant therapy. Our results indicate that overexpression of COL genes might be utilized as novel prognostic markers for GC and assist with therapy selection.

Low expression of RecQ-like helicase 5 is associated with poor prognosis in patients with gastric cancer

The role of RecQ-like helicase 5 (RECQL5) in gastric cancer (GC) is unclear. This study investigated the expression, clinicopathological association and prognosis of RECQL5 protein in human GC. Firstly, the Oncomine database was used to determine the mRNA expression levels of RECQL5 in GC samples. GC samples and adjacent normal gastric tissue samples were subsequently assessed to determine RECQL5 protein expression levels using immunohistochemistry. The clinicopathological association with RECQL5 expression was analyzed. Multivariate Cox analysis was performed to determine the relationship between RECQL5 expression and survival outcomes. Data from the Oncomine database revealed that RECQL5 mRNA was significantly downregulated in GC tissues compared with that in normal gastric tissues (P<0.05). These results were then validated at the protein level as RECQL5 protein expression was found to be significantly downregulated in GC samples compared with that in normal gastric tissues (P<0.05). Low expression of RECQL5 was significantly associated with depth of tumor invasion, histological differentiation and TNM stage (all P<0.05) and indicated poor prognosis in patients with GC. Multivariate analysis revealed that low RECQL5 expression and depth of invasion were independent prognostic factors for GC (P<0.05). These results suggest that low expression of RECQL5 is associated with carcinogenesis and invasion in GC and with poor overall survival in patients with GC. RECQL5 may be a novel prognostic marker for patients with GC.

Evaluation of PAX8 expression promotes the proliferation of stomach Cancer cells

Background

PAX8 was not only a mitotic factor, but identified as a transcription factor involved in the prognosis of human tumor patients. Elucidating the function of PAX8 on the pathology of stomach cancer was meaningful.

Results

PAX8 was found to be upregulated in primary stomach cancer tissue and the TCGA stomach cancer dataset. Interestingly, SOX13 and PAX8 showed consistent expression patterns, and the combined high PAX8 and SOX18 expression induced a worse prognosis of stomach cancer patients. SOX13 was further identified as a transcription factor of PAX8, and further affect Aurora B and Cyclin B1 expression, two cell cycle related factors of the downstream of PAX8, including. Furthermore, PAX8 depletion inducted G1-phase arrest and the decrease of EdU incorporation, cell viability and colony formation can be rescued by SOX13 overexpression.

Conclusions

SOX13 participated in the elevated expression of PAX8, which promote the proliferation of stomach cancer cells. Therefore, SOX13 mediated PAX8 expression was recognized as a tumor-promoting role in stomach cancer.

SOX13 dependent PAX8 expression promotes the proliferation of gastric carcinoma cells

PAX8 is identified as a regulator in the pathogenesis of human tumours and an indicator of the prognosis for patients. However, the role of PAX8 on proliferation in gastric cancer have not been studied. This study was aimed to explore the expression pattern of PAX8 in gastric cancer, and investigate the effect of PAX8 on the proliferation of gastric cancer cells. PAX8 and SOX13 were identified to be synchronously up-regulated in primary gastric cancer in human gastric cancer tissues and the gastric cancer datasets of TCGA, and gastric cancer patients of combined high PAX8 and SOX13 expression showed poor prognosis. Furthermore, SOX13 can mediate PAX8 and its targeted genes, Aurora B and Cyclin B1, expression in AGS and MGC803 cell lines. Flow cytometry and EdU incorporation assays showed that silencing PAX8 can block the cell cycle of gastric cancer cell in G1 phase and SOX13 expression can rescue the arrested proliferative process induced by PAX8 silenced in CCK8 and colony formation assays. Thus, combined SOX13 and PAX8 expression regulate the proliferation of gastric cancer cells, and both SOX13 and PAX8 play an oncogene function in gastric cancer.

microRNA arm-imbalance in part from complementary targets mediated decay promotes gastric cancer progression

Strand-selection is the final step of microRNA biogenesis in which functional mature miRNAs are generated from one or both arms of precursor. The preference of strand-selection is diverse during development and tissue formation, however, its pathological effect is still unknown. Here we find that two miRNA arms from the same precursor, miR-574-5p and miR-574-3p, are inversely expressed and play exactly opposite roles in gastric cancer progression. Higher-5p with lower-3p expression pattern is significantly correlated with higher TNM stages and poor prognosis of gastric cancer patients. The increase of miR-574-5p/-3p ratio, named miR-574 arm-imbalance is partially due to the dynamic expression of their highly complementary targets in gastric carcinogenesis, moreover, the arm-imbalance of miR-574 is in turn involved and further promotes gastric cancer progression. Our results indicate that miR-574 arm-imbalance contribute to gastric cancer progression and re-modification of the miR-574-targets homeostasis may represent a promising strategy for gastric cancer therapy.

Functional miRNAs derived from the 5p or 3p arm of some miRNA duplexes have opposite roles in cancer progression. Here, the authors show that oncogenic miR-574-5p has greater preference in aggressive gastric cancer as compared with miR-574-3p and this arm preference is partly dependent on complementary targets mediated miRNA decay.

Identification of different gene expressions between diffuse- and intestinal-type spheroid-forming gastric cancer cells

BACKGROUND

Three-dimensional in vitro spheroid models are unique because they are considered for enrichment of specific cell populations with self-renewal ability. In this study, we explored the different mechanisms of gastric cancer spheroid-forming cells according to the Lauren classification.

METHODS

We isolated and enriched cells with self-renewal ability using spheroid-forming methods from gastric cancer cell lines. The expression of candidate target genes was investigated using western blot and qRT-PCR analysis. Lentiviral shRNA knockdown of target gene expression was performed and the effects on spheroid, colony forming, and tumorigenic ability were analyzed.

RESULTS

The SNU-638, SNU-484, MKN-28, and NCI-N87 successfully formed spheroid from single cell and enriched for self-renewal ability from 11 gastric cancer cell lines, including diffuse and intestinal types. The expression of SOX2 and E-cadherin increased in spheroid-forming cells in a diffuse-type cell line (SNU-638 and SNU-484), but not in the intestinal type (MKN-28 and NCI-N87). In contrast, ERBB3 expression was only increased in intestinal-type spheroid cells. The depletion of each candidate target gene expression suppressed self-renewal ability to grow as spheroids and colonies in a soft agar assay. In particular, down-regulated ERBB3 in the intestinal-type cell lines inhibited tumor growth in a mouse xenograft model. We found that high ERBB3 gene expression correlates with decreased survival in the intestinal type of gastric cancer.

CONCLUSIONS

Our results suggest that diffuse- and intestinal-type spheroid-forming cells express genes differently. Our data suggest that these candidate genes from spheroid-forming cells can be used in applications in targeted therapy.

High Proportion of Potential Candidates for Immunotherapy in a Chilean Cohort of Gastric Cancer Patients: Results of the FORCE1 Study

Gastric cancer (GC) is a heterogeneous disease. This heterogeneity applies not only to morphological and phenotypic features but also to geographical variations in incidence and mortality rates. As Chile has one of the highest mortality rates within South America, we sought to define a molecular profile of Chilean GCs (ClinicalTrials.gov identifier: NCT03158571/(FORCE1)). Solid tumor samples and clinical data were obtained from 224 patients, with subsets analyzed by tissue microarray (TMA; n = 90) and next generation sequencing (NGS; n = 101). Most demographic and clinical data were in line with previous reports. TMA data indicated that 60% of patients displayed potentially actionable alterations. Furthermore, 20.5% were categorized as having a high tumor mutational burden, and 13% possessed micro-satellite instability (MSI). Results also confirmed previous studies reporting high Epstein-Barr virus (EBV) positivity (13%) in Chilean-derived GC samples suggesting a high proportion of patients could benefit from immunotherapy. As expected, TP53 and PIK3CA were the most frequently altered genes. However, NGS demonstrated the presence of TP53, NRAS, and BRAF variants previously unreported in current GC databases. Finally, using the Kendall method, we report a significant correlation between EBV+ status and programmed death ligand-1 (PDL1)+ and an inverse correlation between p53 mutational status and MSI. Our results suggest that in this Chilean cohort, a high proportion of patients are potential candidates for immunotherapy treatment. To the best of our knowledge, this study is the first in South America to assess the prevalence of actionable targets and to examine a molecular profile of GC patients.

Long noncoding RNA SNHG16 silencing inhibits the aggressiveness of gastric cancer via upregulation of microRNA-628-3p and consequent decrease of NRP1

Background

MicroRNA-628-3p (miR-628) has been reported to play important roles in the progression of multiple human cancer types. Nonetheless, whether the expression profile of miR-628 is altered in gastric cancer remains unclear and whether its aberrant expression plays a crucial part in the aggressiveness of gastric cancer is yet to be determined. Therefore, in this study, we systematically investigated the involvement of miR-628 in gastric cancer progression.

Materials and methods

MiR-628 expression in gastric cancer tissues and cell lines were determined via reverse transcription-quantitative polymerase chain reaction (RT-qPCR). A CCK-8 assay, flow-cytometric analysis, Transwell assays, and a xenograft model experiment were performed to evaluate the influence of miR-628 overexpression on gastric cancer cells. Notably, the mechanisms underlying the tumor-suppressive activity of miR-628 in gastric cancer cells were explored by bioinformatics analysis, a luciferase reporter assay, RT-qPCR, and Western blotting.

Results

MiR-628 expression was low in gastric cancer tissue samples and cell lines. The low expression of miR-628 was closely associated with the lymph node metastasis, invasive depth and TNM stage among patients with gastric cancer. Further clinical analysis indicated that patients with gastric cancer underexpressing miR-628 had a worse prognosis than did the patients with high miR-628 expression in the tumor. Overexpressed miR-628 restrained proliferation, migration, and invasion; induced apoptosis; and impaired tumor growth of gastric cancer cells. In addition, neuropilin 1 (NRP1) mRNA was validated as the direct target of miR-628 in gastric cancer. Long noncoding RNA small nucleolar RNA host gene 16 (SNHG16) was demonstrated to sponge miR-628 in gastric cancer. Moreover, miR-628 knockdown abrogated the influence of SNHG16 silencing on gastric cancer cells.

Conclusion

Our findings elucidate how the SNHG16–miR-628–NRP1 pathway serves as a regulatory network playing crucial roles in gastric cancer progression, suggesting that this pathway may be a novel target of anticancer therapy.

Updates on Management of Gastric Cancer

PURPOSE OF REVIEW

Gastric adenocarcinoma is the fifth most common and the third most lethal cancer worldwide. Surgery is the only chance of cure, but recurrence is common, even with complete resection.

RECENT FINDINGS

Advances in diagnosis and staging, genomic classification, surgical resection and treatment of peritoneal disease, systemic chemotherapy and chemoradiation, and targeted and immune therapies have led to the current multidisciplinary approach to gastric adenocarcinoma. Treatment of gastric cancer is rapidly evolving in an effort to combat this challenging disease.

The DNA Endonuclease Mus81 Regulates ZEB1 Expression and Serves as a Target of BET4 Inhibitors in Gastric Cancer

DNA replication and repair proteins play an important role in cancer initiation and progression by affecting genomic instability. The DNA endonuclease Mus81 is a DNA structure-specific endonuclease, which has been implicated in DNA replication and repair. In this study, we found that Mus81 promotes gastric metastasis by controlling the transcription of ZEB1, a master regulator of the epithelial-mesenchymal transition (EMT). Our results revealed that Mus81 is highly expressed in gastric cancer samples from patients and cell lines compared with their normal counterparts. Particularly, Mus81 expression positively correlated with ZEB1 expression and Mus81 overexpression was significantly associated with higher incidence of lymph node metastasis in patients. Furthermore, Mus81 promoted migration of gastric cancer cells both in vitro and in vivo We conducted a drug screen using a collection of preclinical and FDA-approved drugs and found that the BRD4 inhibitor AZD5153 inhibited the expression of Mus81 and ZEB1 by regulating the epigenetic factor Sirt5. As expected, AZD5153 treatment significantly reduced the migration of gastric cancer cells overexpressing Mus81 in vitro and in vivo Collectively, we show that Mus81 is a regulator of ZEB1 and promotes metastasis in gastric cancer. Importantly, we demonstrate that the BRD4 inhibitor AZD5153 can potentially be used as an effective antimetastasis drug because of its effect on Mus81.

Next-generation Sequencing in the Management of Gastric and Esophageal Cancers

Next-generation sequencing has enabled genome-wide molecular profiling of gastric and esophageal malignancies at single-nucleotide resolution. The resultant genomic profiles provide information about the specific oncogenic pathways that are the likely driving forces behind tumorigenesis and progression. The abundance of available genomic data has immense potential to redefine management paradigms for these difficult disease processes. The ability to capitalize on the information provided through high-throughput sequencing technologies will define cancer care in the coming decades and could shift the paradigm from current stage-based, organ-specific treatments toward tailored regimens that target the specific culprit pathways driving individual tumors.

FOXS1 is regulated by GLI1 and miR-125a-5p and promotes cell proliferation and EMT in gastric cancer

Gastric cancer (GC) is the fourth most common malignant neoplasm and the second leading cause of cancer death. Identification of key molecular signaling pathways involved in gastric carcinogenesis and progression facilitates early GC diagnosis and the development of targeted therapies for advanced GC patients. Emerging evidence has revealed a close correlation between forkhead box (FOX) proteins and cancer development. However, the prognostic significance of forkhead box S1 (FOXS1) in patients with GC and the function of FOXS1 in GC progression remain undefined. In this study, we found that upregulation of FOXS1 was frequently detected in GC tissues and strongly correlated with an aggressive phenotype and poor prognosis. Functional assays confirmed that FOXS1 knockdown suppressed cell proliferation and colony numbers, with induction of cell arrest in the G0/G1 phase of the cell cycle, whereas forced expression of FOXS1 had the opposite effect. Additionally, forced expression of FOXS1 accelerated tumor growth in vivo and increased cell migration and invasion through promoting epithelial–mesenchymal transition (EMT) both in vitro and in vivo. Mechanistically, the core promoter region of FOXS1 was identified at nucleotides −660~ +1, and NFKB1 indirectly bind the motif on FOXS1 promoters and inhibit FOXS1 expression. Gene set enrichment analysis revealed that the FOXS1 gene was most abundantly enriched in the hedgehog signaling pathway and that GLI1 expression was significantly correlated with FOXS1 expression in GC. GLI1 directly bound to the promoter motif of FOXS1 and significantly decreased FOXS1 expression. Finally, we found that miR-125a-5p repressed FOXS1 expression at the translational level by binding to the 3′ untranslated region (UTR) of FOXS1. Together, these results suggest that FOXS1 can promote GC development and could be exploited as a diagnostic and prognostic biomarker for GC.

Homeobox C10 Influences on the Malignant Phenotype of Gastric Cancer Cell Lines and its Elevated Expression Positively Correlates with Recurrence and Poor Survival

BACKGROUND

The detection of molecules and mechanisms affecting the malignant phenotype of gastric cancer cells may contribute to the identification of biomarkers for metastasis and recurrence, and such molecules may serve as targets of therapy. For this purpose, in this study transcriptome analysis was performed using surgically resected specimens from patients with gastric cancer with synchronous metastasis. We identified homeobox C10 (HOXC10) as the most highly expressed gene in gastric cancer tissues compared with the adjacent noncancerous gastric mucosa.

METHODS

Polymerase chain reaction (PCR) array analysis was performed to identify genes coordinately expressed with HOXC10. The effects of inhibiting HOXC10 on malignant phenotype was evaluated using HOXC10 knockout gastric cancer cell lines, and antibody array analysis was performed to assess the effect of HOXC10 knockout on intracellular signaling. We used a mouse subcutaneous xenograft model to evaluate the tumorigenicity. HOXC10 expression was determined in gastric cancer tissues acquired from 300 patients with gastric cancer.

RESULTS

PCR array analysis revealed that the levels of HOXC10 messenger RNA positively correlated with those of FGFBP1 and SOX10. The phosphorylation of ERK1/2 was decreased in HOXC10 knockout cells. HOXC10 knockout significantly suppressed proliferation by increasing apoptosis and reducing the migration and invasiveness of gastric cancer cells. Mouse xenograft models revealed that the tumorigenicity of HOXC10 knockout cells was attenuated compared with the parental cells. The relatively high expression levels of HOXC10 in gastric cancer tissues were significantly associated with hepatic and peritoneal recurrence, as well as worse prognosis.

CONCLUSIONS

Our results indicated that HOXC10 enhances the malignant phenotype of gastric cancer cells. The expression levels of HOXC10 may therefore serve as a prognostic biomarker and the products of HOXC10 may provide targets of therapy.

Special Issue: Cancer Biomarkers and Targets in Digestive Organs

The identification and development of cancer biomarkers and targets have greatly accelerated progress towards precision medicine in oncology. [...].

Purification of equine IgG3 by lectin affinity and an interaction analysis via microscale thermophoresis

The availability of purified antibodies is a prerequisite for many applications and the appropriate choice(s) for antibody-purification is crucial. Numerous methods have been developed for the purification of antibodies from different sources with affinity chromatography-based methods being the most extensively utilized. These methods are based on high specificity, easy reversibility and biological interactions between two molecules (e.g., between receptor and ligand or antibody and antigen). However, no simple techniques have yet been described to characterize and purify subclasses of immunoglobulins (Ig) from some animals of biotechnology importance such as equines, which are frequently used to produce biotherapeutic antibodies. The sera of these animals present a large number of Ig classes that have a greater complexity than other animals. The implementation of an effective protocol to purify the desired antibody class/subclasses requires meticulous planning to achieve yields at a high purity. The IgG3 subclass of equine-Ig has recently been used as antigen in a new diagnostic test for allergic responses to horse sera-based therapies. Here, we defined a simple method using Jacalin lectin immobilized on Sepharose beads to prepare highly pure equine IgG3 antibodies with a determination of the affinity constants for Jacalin lectin and horse IgG3.

High expression of ZBED1 affects proliferation and apoptosis in gastric cancer

BACKGROUND

ZBED1 (zinc finger BED-type containing 1) is a transcription factor. However, its expression, role and clinical significance in cancer are unclear. The purpose of this study is to investigate the expression of ZBED1 and its effect on the proliferation of gastric cancer (GC).

METHODS

Quantitative PCR was used to detect the mRNA level of ZBED1 in GC tissues and normal gastric tissues. Proliferation and colony formation assays were conducted when ZBED1 was expressed ectopically or silenced by constructed vectors. Moreover, chemotherapy-drug induced apoptosis rates were examined by flow cytometry when ZBED1 was expressed ectopically or silenced.

RESULTS

The mRNA level of ZBED1 was significantly elevated in 10 out of 11 cases of GC tumor tissue specimens. Results of our analysis derived from a public clinical microarray database suggest that a high expression of ZBED1 predicts a poor outcome. ZBED1 promotes cell proliferation and colony formation. Moreover, ZBED1 decreased the chemosensitivity of GC cells.

CONCLUSIONS

ZBED1 expression is up-regulated in GC cells. ZBED1 promotes proliferation and decreases the chemosensitivity of GC cells. ZBED1 may be a potential therapeutic target and predictive biomarker in gastric cancer.

An anti-ASCT2 monoclonal antibody suppresses gastric cancer growth by inducing oxidative stress and antibody dependent cellular toxicity in preclinical models

Glutamine is a major nutrient for cancer cells during rapid proliferation. Alanine-serine-cysteine (ASC) transporter 2 (ASCT2; SLC1A5) mediates glutamine uptake in a variety of cancer cells. We previously reported that KM8094, a novel anti-ASCT2 humanized monoclonal antibody, possesses anti-tumor efficacy in gastric cancer patient-derived xenografts. The aim of this study was to investigate the molecular mechanism underlying the effect of KM8094 and to further substantiate the preclinical feasibility of using KM8094 as a potential therapeutic agent against gastric cancer. First, ASCT2 was found to be highly expressed in cancer tissues derived from gastric cancer patients by an immunohistochemical analysis. Next, we performed in vitro studies using multiple gastric cancer cell lines and observed that several gastric cancer cells expressing ASCT2 showed glutamine-dependent cell growth, which was repressed by KM8094. We found that KM8094 inhibited the glutamine uptake, leading to the reduction of glutathione (GSH) level and the elevation of oxidative stress. KM8094 suppressed the cell cycle progression and increased the apoptosis. Furthermore, KM8094 exerted antibody dependent cellular cytotoxicity (ADCC) against human gastric cancer cells in vitro. Finally, in vivo studies revealed that KM8094 suppressed tumor growth in several gastric cancer xenografts. This effect was enhanced by docetaxel, one of the agents commonly used in gastric cancer therapy. Thus, our findings suggest that KM8094 is a potential new therapeutic agent for gastric cancer expressing ASCT2, which blocks the cellular glutamine metabolism and possesses ADCC activity.

Genomic markers of resistance to targeted treatments in gastric cancer: potential new treatment strategies

Gastric cancer is a highly heterogeneous disease, displaying a complex genomic landscape and an unfavorable outcome with standard therapies. Based on distinctive genomic alterations, novel targeted agents have been developed with the aim of personalizing treatments and improving patient outcome. However, a subgroup of patients is primarily treatment-resistant, and even in the initially sensitive population, secondary resistance emerges, thus limiting therapeutic benefit. In this review, we summarize the clinical data about standard targeted agents in gastric cancer, specifically anti-HER2 treatments and antivascular therapies. We also illustrate the available evidence regarding molecular mechanisms of resistance to these agents and we discuss potential strategies for new targeted treatments that could overcome such resistance.

TERT expression in gastric carcinogenesis: Correlation with clinical features

AIM

To investigate the expression of telomerase reverse transcriptase (TERT) mRNA in gastric cancer and precancerous lesions, and to analyze the relationship between TERT expression and clinicopathologic features and prognosis in gastric cancer.

METHODS

From September 2011 to October 2016, 102 patients with gastric cancer, 32 patients with precancerous lesions, and 30 patients with chronic non-atrophic gastritis were treated at the First Affiliated Hospital of Jiamus University. The expression of TERT mRNA in tissues was detected by real-time quantitative PCR, and the correlation of expression of TERT with clinicopathologic features and prognosis in gastric cancer was analyzed.

RESULTS

The expression of TERT in gastric cancer and precancerous lesions was significantly higher than that in chronic non-atrophic gastritis (P < 0.05). TERT expression was significantly correlated with the depth of invasion, TNM stage, vascular invasion, and lymph node metastasis (P < 0.05). The overall survival rate of gastric cancer patients with high expression of TERT was significantly lower than that of patients with low expression of TERT (HR = 0.420, 95%CI: 0.264-0.668, P < 0.001). The progression-free survival rate of gastric cancer patients with high expression of TERT was also significantly lower than that of patients with low TERT expression (HR = 0.649, 95%CI: 0.421-0.999, P = 0.049). Cox multivariate survival analysis showed that TERT expression was an independent prognostic factor for overall survival in gastric cancer.

CONCLUSION

TERT is highly expressed in gastric cancer and precancerous lesions, and high expression of TERT is significantly associated with the clinicopathologic features and prognosis of gastric cancer patients.