Novel Systemic Therapies for Advanced Gastric Cancer

System biology approaches for drug repurposing

Drug repurposing, or drug repositioning, refers to the identification of alternative therapeutic applications for established medications that go beyond their initial indications. This strategy has becoming increasingly popular since it has the potential to significantly reduce the overall costs of drug development by around $300 million. System biology methodologies have been employed to facilitate medication repurposing, encompassing computational techniques such as signature matching and network-based strategies. These techniques utilize pre-existing drug-related data types and databases to find prospective repurposed medications that have minimal or acceptable harmful effects on patients. The primary benefit of medication repurposing in comparison to drug development lies in the fact that approved pharmaceuticals have already undergone multiple phases of clinical studies, thereby possessing well-established safety and pharmacokinetic properties. Utilizing system biology methodologies in medication repurposing offers the capacity to expedite the discovery of viable candidates for drug repurposing and offer novel perspectives for structure-based drug design.

In Silico Investigation of Novel Compounds as Inhibitors of Acetylcholinesterase Enzyme for the Treatment of Alzheimer's Diseases

Alzheimer's disease (AD) is a "progressive, neurodegenerative disease that occurs when nerve cells in the brain die." There are only 4 drugs approved by the United States Food and Drug Administration (FDA). Three (donepezil, rivastigmine, and galantamine) out of these four drugs are anticholinesterase inhibitors, while the fourth one memantine is an N-methyl-D-aspartate (NMDA) receptor inhibitor. Currently, two immunotherapy drugs that target amyloid protein (donanemab and lecanemab) are being considered for the treatment of Alzheimer's disease at an early stage. All these drug molecules are still not the complete answer to the treatment of Alzheimer's disease. A recent report from the Office of National Statistics showed that AD is the leading cause of death in 2022. Therefore, there is an urgency to develop more drugs that can treat AD. Based on this urgency, we aim to investigate how bioactive and already approved drugs could be repurposed for inhibiting the anticholinesterase enzyme using computational studies. To achieve this, the data science tool-Python coding was compiled on Jupyter Notebook to mine bioactive compounds from the ChEMBL database. The most bioactive compounds obtained were further investigated using Molecular Operating Environment (MOE) software to carry out molecular docking and ligand analysis, and this was followed by molecular dynamics simulation production at 35 ns using GROMACS 2022.4 on Archer 2 machine. The molecular dynamic analysis was carried out using HeroMDanalysis software. Data mining of the ChEMBL database was carried out for lipase inhibitors, and this gave CHEMBL-ID 1240685, a peptide molecule, the most active compound at the time of data mining. Further literature studies gave Zoladex an FDA-approved drug for the treatment of breast cancer as another compound of interest. The in silico studies were carried out against the anticholinesterase enzyme using two FDA-approved drugs donepezil and galantamine as a template for comparing the in silico activities of the repurposed drugs. A very useful receptor for this study was PDB-1DX6, a cocrystallized galantamine inhibitor of acetylcholinesterase enzyme. The molecular docking analysis (using ligand interactions) and molecular dynamic analysis (root mean square deviation (RMSD) and root mean square fluctuation (RMSF)) showed that the two peptide molecules CHEMBL-1240685 and Zoladex gave the best binding energy and stability when compared to the FDA-approved drugs (donepezil and galantamine). Finally, further literature studies revealed that Zoladex affects memory reduction; therefore, it was dropped as a possible repurposed drug. Our research showed that CHEMBL-1240685 is a potential compound that could be investigated for the inhibition of anticholinesterase enzyme and might be another drug molecule that could be used to treat Alzheimer's disease.

Current trends and future prospects of drug repositioning in gastrointestinal oncology

Gastrointestinal (GI) cancers comprise a significant number of cancer cases worldwide and contribute to a high percentage of cancer-related deaths. To improve survival rates of GI cancer patients, it is important to find and implement more effective therapeutic strategies with better prognoses and fewer side effects. The development of new drugs can be a lengthy and expensive process, often involving clinical trials that may fail in the early stages. One strategy to address these challenges is drug repurposing (DR). Drug repurposing is a developmental strategy that involves using existing drugs approved for other diseases and leveraging their safety and pharmacological data to explore their potential use in treating different diseases. In this paper, we outline the existing therapeutic strategies and challenges associated with GI cancers and explore DR as a promising alternative approach. We have presented an extensive review of different DR methodologies, research efforts and examples of repurposed drugs within various GI cancer types, such as colorectal, pancreatic and liver cancers. Our aim is to provide a comprehensive overview of employing the DR approach in GI cancers to inform future research endeavors and clinical trials in this field.

Novel HER2-targeted therapy to overcome trastuzumab resistance in HER2-amplified gastric cancer

Trastuzumab is used to treat HER2-amplified metastatic gastric cancer; however, most patients become trastuzumab-resistant within a year. Knowledge of the mechanisms underlying trastuzumab resistance is required to overcome this limitation. Here, we aimed to elucidate this resistance mechanism using four trastuzumab-resistant (TR) cell lines and investigate the efficacy of HER2-targeted therapies to overcome treatment resistance. Each TR cell line had different phenotypic characteristics. Interestingly, HER2 expression remained as high as the parental cell lines in TR cell lines, suggesting that HER2-targeted agents were still useful. As expected, three tyrosine kinase inhibitors (lapatinib, neratinib, and tucatinib) and one antibody-drug conjugate (trastuzumab deruxtecan: T-DXd) exhibited good antitumor effects against TR cell lines. We further investigated the potential biological mechanism of T-DXd. When treated with trastuzumab or T-DXd, HER2 or its downstream signals were disrupted in parental cell lines, but not in TR cell lines. Moreover, T-DXd induced the expression of pH2A.X and cPARP and caused cell cycle arrest in the S or G2-M phase in TR cell lines. T-DXd showed promising antitumor activity in both parental and TR cell lines, suggesting that it is a potential candidate for overcoming trastuzumab resistance.

Nivolumab Plus Chemotherapy for Advanced Gastric, Gastroesophageal Junction, and Esophageal Adenocarcinoma: Analysis of Number Needed To Treat and Number Needed To Harm

PURPOSE

Nivolumab, a programmed cell death protein (PD)-1 inhibitor, was approved by the US Food and Drug Administration in 2021 advanced/metastatic gastric cancer, gastroesophageal junction cancer, and esophageal adenocarcinoma, in combination with fluoropyrimidine and platinum-based chemotherapy. In the present study, the number needed to treat (NNT) for overall survival (OS), progression-free survival (PFS), and objective response rate (ORR)-and the number needed to harm (NNH) for tolerability outcomes-with nivolumab + chemotherapy versus chemotherapy alone were determined.

METHODS

NNT and NNH were calculated as the reciprocal of the risk difference between the two treatment arms, with the 95% CIs calculated as the reciprocals of the upper and lower bounds of the 95% CI of the risk difference, using data from the CheckMate 649 study.

FINDINGS

Among all treated patients, the NNTs for OS over 1 and 2 years were 15.15 and 12.05; for PFS, 10.87 and 19.61; and for ORR over the entire trial period, 8.95. The corresponding NNTs in the subgroup with PD-L1 CPS ≥5 were less. The NNH for grade ≥3 treatment-related adverse events (TEAEs) over 1 year among all treated patients was 7.02.

IMPLICATIONS

The small estimated NNT values in this study suggest that patients would benefit from nivolumab + chemotherapy, and while the NNH for grade ≥3 TRAEs was small, the NNH for any individual TRAE were large or negative.

ISLR interacts with MGAT5 to promote the malignant progression of human gastric cancer AGS cells

Objectives

Gastric cancer is a common malignant tumor with high morbidity and mortality. The present study aimed to investigate the role of the immunoglobulin superfamily containing leucine-rich repeat (ISLR) gene in gastric cancer and examine whether ISLR could interact with N-acetylglucosaminyltransferase V (MGAT5) to affect the malignant progression of gastric cancer.

Materials and Methods

The expression of ISLR and MGAT5 in human normal gastric epithelial cells and human gastric cancer cells, and the transfection efficiency of ISLR interference plasmids and MGAT5 overexpression plasmids were all detected by reverse transcription-quantitative PCR (RT-qPCR) and western blot. The viability, proliferation, migration and invasion, and epithelial-mesenchymal transition (EMT) of gastric cancer cells after indicated transfection were detected by Cell counting kit-8 (CCK-8) assay, 5-ethynyl-2'-deoxyuridine (EdU) staining, wound healing assay, and transwell assay. The interaction between ISLR and MGAT5 was confirmed by co-immunoprecipitation. The expression of proteins related to migration, invasion, and EMT was detected by immunofluorescence and western blot.

Results

As a result, ISLR was highly expressed in gastric cancer and was associated with poor prognosis. Interference with ISLR inhibited the viability, proliferation, migration, invasion, and EMT of gastric cancer cells. ISLR interacted with MGAT5 in gastric cancer cells. MGAT5 overexpression weakened the effects of ISLR knockdown on suppressing the viability, proliferation, migration, invasion, and EMT of gastric cancer cells.

Conclusion

ISLR interacted with MGAT5 to promote the malignant progression of gastric cancer.

Case report: Significant response to PD-L1 inhibitor after resistance to PD-1 inhibitor in an advanced alpha-fetoprotein-positive gastric cancer

Alpha-fetoprotein-positive gastric cancer (AFPGC) is a type of gastric cancer with a high degree of malignancy. The disease is more common in the elderly, with a high prevalence in males and generally atypical clinical manifestations. For advanced patients, the current treatment options are limited and, to date, few cases of advanced AFPGC have been treated successfully with conventional chemotherapy. With the development of molecular biology and immunology, tumor immunotherapy offers more therapeutic options to patients with advanced gastric cancer. This study describes a case of advanced gastric cancer in a young woman with a high blood alpha-fetoprotein (AFP) level (>54,000 ng/mL). The patient showed initial promising results when programmed cell death-1 (PD-1) inhibitor treatment was combined with chemotherapy after systemic chemotherapy failed. When the disease progressed again after 129 days, adjustment of the treatment regimen to Atezolizumab in combination with Irinotecan and Surufatinib capsules achieved partial remission (PR). There were no immune-related pneumonia, myocarditis, or other adverse effects observed. The patient currently has an overall survival of more than 14 months. This case demonstrated that switching from PD-1 inhibitor to programmed cell death-Ligand 1 (PD-L1) inhibitor therapy may overcome potential resistance. It providing a reference for immunotherapy of patients with AFP-positive advanced gastric cancer.

System and network biology-based computational approaches for drug repositioning

Recent advances in computational biology have not only fastened the drug discovery process but have also proven to be a powerful tool for the search of existing molecules of therapeutic value for drug repurposing. The system biology-based drug repurposing approaches shorten the time and reduced the cost of the whole process when compared to de novo drug discovery. In the present pandemic situation, these computational approaches have emerged as a boon to tackle the COVID-19 associated morbidities and mortalities. In this chapter, we present the overview of system biology-based network system approaches which can be exploited for the drug repurposing of disease. Besides, we have included information on relevant repurposed drugs which are currently used for the treatment of COVID-19.

Significance of Tumor Mutation Burden Combined With Immune Infiltrates in the Progression and Prognosis of Advanced Gastric Cancer

Gastric cancer (GC) is a serious malignant tumor with high mortality and poor prognosis. The prognosis and survival are much worse for advanced gastric cancer (AGC). Recently, immunotherapy has been widely promoted for AGC patients, and studies have shown that tumor mutation burden (TMB) is closely related to immunotherapy response. Here, RNA-seq data, matched clinical information, and MAF files were downloaded from the cancer genome atlas (TCGA)-STAD project in the TCGA database. The collation and visual analysis of mutation data were implemented by the “maftools” package in R. We calculated the TMB values for AGC patients and divided the patients into high- and low-TMB groups according to the median value of TMB. Then, the correlation between high or low TMB and clinicopathological parameters was calculated. Next, we examined the differences in gene expression patterns between the two groups by using the “limma” R package and identified the immune-related genes among the DEGs. Through univariate Cox regression analysis, 15 genes related to prognosis were obtained. Furthermore, the two hub genes (APOD and SLC22A17) were used to construct a risk model to evaluate the prognosis of AGC patients. ROC and survival curves and GEO data were used as a validation set to verify the reliability of this risk model. In addition, the correlation between TMB and tumor-infiltrating immune cells was examined. In conclusion, our results suggest that AGC patients with high TMB have a better prognosis. By testing the patient’s TMB, we could better guide immunotherapy and understand patient response to immunotherapy.

Significance of Tumor Mutation Burden Combined With Immune Infiltrates in the Progression and Prognosis of Advanced Gastric Cancer

Gastric cancer (GC) is a serious malignant tumor with high mortality and poor prognosis. The prognosis and survival are much worse for advanced gastric cancer (AGC). Recently, immunotherapy has been widely promoted for AGC patients, and studies have shown that tumor mutation burden (TMB) is closely related to immunotherapy response. Here, RNA-seq data, matched clinical information, and MAF files were downloaded from the cancer genome atlas (TCGA)-STAD project in the TCGA database. The collation and visual analysis of mutation data were implemented by the “maftools” package in R. We calculated the TMB values for AGC patients and divided the patients into high- and low-TMB groups according to the median value of TMB. Then, the correlation between high or low TMB and clinicopathological parameters was calculated. Next, we examined the differences in gene expression patterns between the two groups by using the “limma” R package and identified the immune-related genes among the DEGs. Through univariate Cox regression analysis, 15 genes related to prognosis were obtained. Furthermore, the two hub genes (APOD and SLC22A17) were used to construct a risk model to evaluate the prognosis of AGC patients. ROC and survival curves and GEO data were used as a validation set to verify the reliability of this risk model. In addition, the correlation between TMB and tumor-infiltrating immune cells was examined. In conclusion, our results suggest that AGC patients with high TMB have a better prognosis. By testing the patient’s TMB, we could better guide immunotherapy and understand patient response to immunotherapy.

Estrogen-related receptor-gamma influences Helicobacter pylori infection by regulating TFF1 in gastric cancer

Helicobacter pylori infection is a crucial factor in the development of gastric cancer (GC). Molecular therapeutic targets and mechanisms contributing to H. pylori infection-associated GC induction are poorly understood and this study aimed to fill that research gap. We found that the nuclear receptor estrogen-related receptor gamma (ESRRG) is a candidate factor influencing H. pylori infection-driven GC. ESRRG suppressed H. pylori infection and cell growth induced by H. pylori infection in GC cells and organoid models In addition, H. pylori infection downregulates ESRRG expression. Gene expression profiling revealed that trefoil factor 1 (TFF1), a well-known tumor suppressor in GC, is a downstream target of ESRRG. Mechanistically, ESRRG directly binds to the TFF1 promoter and induces TFF1 gene expression. Furthermore, TFF1 activation by ESRRG was inhibited by nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB)/p65, which is induced by inflammation, such as by H. pylori infection. Our current study provides new molecular insights into how ESRRG regulates H. pylori infection, contributing to GC development. We suggest that modulation of ESRRG-suppressing H. pylori infection could be a therapeutic target for the treatment of GC patients.

The impact of microRNAs on myeloid-derived suppressor cells in cancer

Inflammation promotes cancer development. To a large extent, this can be attributed to the recruitment of myeloid-derived suppressor cells (MDSCs) to tumors. These cells are known for establishing an immunosuppressive tumor microenvironment by suppressing T cell activities. However, MDSCs also promote metastasis and angiogenesis. Critically, as small non-coding RNAs that regulate gene expression, microRNAs (miRNAs) control MDSC activities. In this review, we discuss how miRNA networks regulate key MDSC signaling pathways, how they shape MDSC development, differentiation and activation, and how this impacts tumor development. By targeting the expression of miRNAs in MDSCs, we can alter their main signaling pathways. In turn, this can compromise their ability to promote multiple hallmarks of cancer. Therefore, this may represent a new powerful strategy for cancer immunotherapy.

MicroRNA-29b-3p Inhibits the Migration and Invasion of Gastric Cancer Cells by Regulating the Autophagy-Associated Protein MAZ

Purpose

The purpose of this study was to investigate the relationship between microRNA-29b-3p (miR-29b-3p) and myc-associated zinc finger protein (MAZ) expression and the effects of this interaction on the proliferation, migration, and invasion of gastric cancer cells.

Methods

qPCR and Western blots were used to detect the expression of miR-29b-3p and MAZ. The dual luciferase reporter gene system was used to explore whether MAZ is the target of miR-29b-3p. Cell function experiments and a mouse tumorigenesis model were used to determine the effects of miR-29b-3p overexpression and MAZ depletion on proliferation, migration, and invasion in gastric cancer cell lines and on tumor growth.

Results

The expression level of miR-29b-3p was low and the expression level of MAZ was high in gastric cancer cells compared with normal human gastric mucosal epithelial cells. MAZ was the target gene of miR-29b-3p. The upregulation of miR-29b-3p reduces the expression of MAZ. Overexpression of miR-29b-3p and downregulation of MAZ inhibited the proliferation and migration of cancer cells and induced apoptosis by controlling the expression of autophagy-related proteins. MiR-29b-3p mimics inhibit tumor growth in mice.

Conclusion

MiR-29b-3p inhibits the migration and invasion of gastric cancer cells by regulating the autophagy-related protein MAZ.

Association of tumor-infiltrating T lymphocytes with intestinal-type gastric cancer molecular subtypes and outcome

While host immune response is likely to be important for the prognosis of gastric cancer patients, detailed information on the T lymphocyte infiltration in different gastric cancer subtypes is lacking. Here, we studied the presence of CD3, CD8, and FOXP3 (Forkhead box p3) expressing T lymphocytes in a retrospective cohort of 190 intestinal gastric and gastroesophageal adenocarcinomas. The cancers represented four distinct molecular subtypes: Epstein-Barr virus-positive (EBV+), mismatch-repair-deficient (MMR-D), aberrant TP53, and the "other" subtype. The absolute numbers of CD3+, CD8+, and FOXP3+ T lymphocytes were analyzed in relation with these molecular subtypes and selected clinicopathological parameters. Overall, there was a large variation in the amount of infiltrating T lymphocyte in all molecular subtypes. Among the subtypes, EBV+ cancers differed from the other subtypes in increased lymphocyte infiltration and high CD8+/FOXP3+ ratio. While the TP53 aberrant subtype did not differ in the absolute amount of T lymphocyte, the ratio of CD8+/FOXP3+ and CD3+/FOXP3+ cells was highest in this subtype, possibly reflecting immunosuppression associated with genomic instability. Increased CD3+ and CD8+ T lymphocyte infiltrates were associated with better survival, and remained as independent prognostic factors in a multivariate analysis. This study is the first to investigate lymphocytic infiltration within four molecular subtypes of intestinal-type gastric cancer in a European cohort. The results provide an important addition to the current knowledge of T lymphocyte-dependent immune response in gastric cancer and its prognostic significance.

p16 methylation is a potential predictive marker for abemaciclib sensitivity in gastric cancer

Cell cycle control is often disrupted in gastric cancer (GC), making it an attractive therapeutic target. Abemaciclib is a specific CDK4/6 inhibitor that has been shown to improve treatment efficacy in hormone receptor-positive advanced breast cancer; however, its potential therapeutic value and predictive markers have not yet been revealed in GC. In this study, we investigated the efficacy of abemaciclib using preclinical GC models representing defined molecular subtypes from The Cancer Genome Atlas. In these 49 GC cell lines, Epstein-Barr virus (EBV) and high microsatellite instability (MSI-H)-type cell lines were p16 methylated and sensitive to abemaciclib; further, genomically stable (GS), and chromosomal instability (CIN)-type cell lines with p16 methylation and intact Rb were also found to be responsive. In addition, we found that GC patients with p16 methylation often displayed a poor prognosis. Collectively, these data provide a foundation for clinical trials to assess the therapeutic efficacy of abemaciclib in GC and suggest that p16 methylation could be used as a predictive marker to identify patients with GC who may benefit from abemaciclib-based therapies.

Drug Repositioning: New Approaches and Future Prospects for Life-Debilitating Diseases and the COVID-19 Pandemic Outbreak

Traditionally, drug discovery utilises a de novo design approach, which requires high cost and many years of drug development before it reaches the market. Novel drug development does not always account for orphan diseases, which have low demand and hence low-profit margins for drug developers. Recently, drug repositioning has gained recognition as an alternative approach that explores new avenues for pre-existing commercially approved or rejected drugs to treat diseases aside from the intended ones. Drug repositioning results in lower overall developmental expenses and risk assessments, as the efficacy and safety of the original drug have already been well accessed and approved by regulatory authorities. The greatest advantage of drug repositioning is that it breathes new life into the novel, rare, orphan, and resistant diseases, such as Cushing's syndrome, HIV infection, and pandemic outbreaks such as COVID-19. Repositioning existing drugs such as Hydroxychloroquine, Remdesivir, Ivermectin and Baricitinib shows good potential for COVID-19 treatment. This can crucially aid in resolving outbreaks in urgent times of need. This review discusses the past success in drug repositioning, the current technological advancement in the field, drug repositioning for personalised medicine and the ongoing research on newly emerging drugs under consideration for the COVID-19 treatment.

High expression of GNB4 predicts poor prognosis in patients with Helicobacter pylori-positive advanced gastric cancer

Background

Helicobacter pylori (H. pylori) is recognized as the most evident etiologic factor of infection-related gastric cancer (GC) and its involvement in GC initiation and progression has been well investigated. However, only a limited number of studies were performed to identify prognostic biomarkers and evaluate their clinical significance in GC patients infected with H. pylori. This study was conducted to investigate the clinical significance as well as its potential prognostic value of GNB4 in H. pylori-positive GC patients receiving standard treatment.

Methods

Retrospective statistical analysis was performed on 448 H. pylori-positive GC patients, with 137 early gastric cancer (EGC) patients undergoing radical gastrectomy alone and 311 advanced gastric cancer (AGC) patients receiving the same surgical procedure followed by fluorouracil-based chemotherapy. GNB4 expression was detected by immunohistochemistry staining on patient samples. H. pylori infection was routinely examined on endoscopic biopsy and/or surgical specimen of GC patients.

Results

High expression of GNB4 was 65.7% (90/137) in EGC and 62.7% (195/311) in AGC patients infected with H. pylori, respectively. In EGC patients, GNB4 expression was not associated with either clinicopathological parameters or 5-year overall survival (OS). In AGC patients however, high expression of GNB4 was significantly associated with patient’s pathological stage (P=0.047). Univariate analysis showed that tumor invasion depth (P=0.001), lymph node metastasis (P<0.001), pathological stage (P<0.001) as well as high expression of GNB4 (P=0.002) were significantly associated with 5-year OS. Multivariate analysis further identified lymph node metastasis (P=0.013) and GNB4 high expression (P=0.020) as independent prognostic factors for long-term outcome of H. pylori-positive AGC patients.

Conclusions

This study demonstrates that high expression of GNB4 is significantly associated with pathological stage of AGC patients with H. pylori infection. GNB4 expression independently predicts the 5-year OS of H. pylori-positive AGC patients undergoing radical gastrectomy and adjuvant chemotherapy.

Identification and validation of stromal-tumor microenvironment-based subtypes tightly associated with PD-1/PD-L1 immunotherapy and outcomes in patients with gastric cancer

Background

Immunotherapies targeting programmed cell death 1 (PD-1) and programmed death-ligand 1 (PD-L1) have been approved for gastric cancer (GC) patients. However, a large proportion of patients with T-cell-inflamed tumor microenvironment do not respond to the PD-1/PD-L1 blockade. The stromal component of the tumor microenvironment has been associated with immunotherapy. This study aims to explore the clinical significance of the non-immune cells in the tumor microenvironment and their potential as biomarkers for immunotherapy.

Methods

A total of 383 patients with GC from the Cancer Genome Atlas (TCGA) cohort, 300 patients with GC from the GSE62254 cohort in Gene Expression Omnibus (GEO) were included in the study. A stromal score was generated using the ESTIMATE algorithm, and the likelihood of response to PD-1/PD-L1 immunotherapy of GC patients was predicted using the TIDE algorithm. The prognostic value of the stromal score from GC cases was evaluated by the Kaplan–Meier method and Cox regression analysis. Gene set enrichment analysis (GSEA) was also conducted.

Results

The stromal score showed significant differences in different molecular subtypes and T stages. Multivariate analyses further confirmed that the stromal score was an independent indicator of overall survival (OS) in the two cohorts. The low stromal score group showed higher tumor mutation burden (TMB) and micro-satellite instability (MSI), and was more sensitive to immune checkpoint inhibitor according to the TIDE algorithm. Activation of the transforming growth factor and epithelial–mesenchymal transition were observed in the high stromal score subtype, which is associated with T-cell suppression, and may be responsible for resistance to PD-1/PD-L1 therapy. BPIFB2 was confirmed as a hub gene relevant to immunotherapy.

Conclusion

The stromal score was associated with cancer progression and molecular subtypes, and may serve as a novel biomarker for predicting the prognosis and response to immunotherapy in patients with GC.

Zinc Finger Protein 521, Negatively Regulated by MicroRNA-204-5p, Promotes Proliferation, Motility and Invasion of Gastric Cancer Cells

OBJECTIVE

This study aims to investigate the expression, role, and detailed mechanism of microRNA-204-5p and zinc finger protein 521 in gastric cancer.

METHODS

Immunohistochemistry was adopted to detect the expressions of zinc finger protein 521 in 82 cases of gastric cancer tissues. Western blot was used to detect the expressions of zinc finger protein 521 in gastric cancer cells and adjacent cells. Moreover, the correlation between zinc finger protein 521 and the prognosis of patients were also evaluated. Cell Counting Kit 8 assay and colony formation assay were performed to figure out the impact of zinc finger protein 521 on the proliferation of gastric cancer cells. By conducting flow cytometry, the effect of zinc finger protein 521 on the apoptosis of gastric cancer cells was determined. The scratch wound healing assay and transwell invasion assay were carried out to determine the effect of zinc finger protein 521 on regulating the motility and invasion of gastric cancer cells. Ultimately, the targeting relationship and interaction between microRNA-204-5p and zinc finger protein 521 were verified by real-time polymerase chain reaction, Western blot, and dual luciferase reporter gene assay.

RESULTS

Compared with adjacent cells, zinc finger protein 521 was highly expressed in gastric cancer cells, which was related to TNM stage (P = .0388), tumor size (P = .0168), and local lymph node metastasis (P = .0024). Overexpressed zinc finger protein 521 can promote the proliferation, migration, and invasion of gastric cancer cells and inhibit the apoptosis. Zinc finger protein 521 is a target gene of microRNA-106-5p, and there was a negative correlation between the expression of zinc finger protein 521 and microRNA-204-5p.

CONCLUSION

Zinc finger protein 521 can arrest the apoptosis and enhance the proliferation, migration, and invasion of gastric cancer cells via regulating microRNA-204-5p. Our study may provide novel clues for the treatment of patients with gastric cancer.

Review of the Application of Nanovesicles and the Human Interstitial Fluid in Gastrointestinal Premalignant Lesion Detection, Diagnosis, Prognosis and Therapy

Premalignant lesions arise from cells that abnormally proliferate and have a tendency to become cancerous. Developing methods to specifically target and remove these premalignant lesions is imperative to the prevention of malignant progression into gastrointestinal (GI) tumors. However, accurate detection and diagnosis of GI precancerous lesions is challenging, as these lesions show little or no structural change. Thus, this prevents early intervention and reduces the success rate of therapy. In this review, we performed a systematic analysis of the technological advancements in the combined application of nanovesicles (NVs) and the human interstitial fluid (HIF) to specifically target GI premalignant lesions. NVs, which include quantum dots (QDs), are small membranous vehicles of a nanometer diameter that are widely used as drug delivery vectors, therapeutic effectors and diagnostic sensors. HIF is the fluid that is present in human interstitial tissues (HITs) in which signaling molecules and agents travel and can be found throughout the body. HIF is exploited by tumor cells for their invasion, migration and spread. Because the HITs span the entire submucosa of the gastrointestinal tract, they have been increasingly targeted in GI tumor therapy. The challenges involved in the combined application of NVs and HIF in the detection, diagnosis, prognosis and therapy of GI premalignant lesions are also discussed.

Gastric cancer-derived mesenchymal stromal cells trigger M2 macrophage polarization that promotes metastasis and EMT in gastric cancer

Resident macrophages in the tumor microenvironment exert a dual role in tumor progression. So far, the mechanism of intratumoral macrophage generation is still largely unknown. In the present study, the importance of macrophages in the pro-tumor role of gastric cancer-derived mesenchymal stromal cells (GC-MSCs) was observed in a mouse xenograft model with macrophage depletion. In gastric cancer tissues, high expression levels of Ym-1, Fizz-1, arginase-1, and CCR-2, as well as a low expression level of iNOS, were verified, and co-localization of GC-MSCs and tumor-associated macrophages (TAMs) was observed by dual immunofluorescence histochemistry. TAMs isolated from gastric cancer tissues predominantly displayed an M2 phenotype. In a co-culture system, the contribution of GC-MSCs to M2 polarization of macrophages was confirmed by the M2-related protein expression, M2-like immunophenotype and cytokine profile of GC-MSC-primed macrophages in vitro. Blockade of IL-6/IL-8 by neutralizing antibodies significantly attenuated the promoting effect of GC-MSCs on M2-like macrophage polarization via the JAK2/STAT3 signaling pathway. In addition, GC-MSC-primed macrophages promoted the migration and invasion of gastric cancer cells, and the process of EMT in gastric cancer cells was significantly enhanced by GC-MSC-primed macrophage treatment. Our study showed that tumor-promoting GC-MSCs contribute to M2 macrophage polarization within the gastric cancer niche through considerable secretion of IL-6 and IL-8. These GC-MSC-primed macrophages can subsequently prompt gastric cancer metastasis via EMT promotion in gastric cancer cells.

CMIP promotes Herceptin resistance of HER2 positive gastric cancer cells

Gastric cancer remains one of the most malignant human cancers with poor prognosis. Herceptin is a well-received antibody drug for HER2 positive gastric cancer. Primary Herceptin resistance and acquired Herceptin resistance retarded the use of Herceptin for gastric cancer. We herein reported CMIP (C-Maf-inducing protein) was overexpressed in Herceptin-resistant gastric cancer cells MKN45-HR and NCI-N87-HR; CMIP promoted Herceptin resistance of HER2 positive gastric cancer cells. SOX2 was examined to be positively regulated by CMIP and also promoted Herceptin resistance of HER2 positive gastric cancer cells. SOX2 might mediate the Herceptin resistance promoting role of CMIP in gastric cancer cells. Elevated expression of CMIP was associated with poor clinicopathological features including tumor size, lymph node metastasis and clinical stage in HER2 positive gastric cancer patients. Inhibitors of CMIP could be used as potential adjuvant therapeutic drugs for HER2 positive gastric cancer.

GJB4 promotes gastric cancer cell proliferation and migration via Wnt/CTNNB1 pathway

Background

Gap junction beta-4 protein (GJB4), or connexin 30.3, a member of integral membrane proteins, has been shown to involve and may function as a tumor promoter in tumorigenesis. However, the role of GJB4 in gastric cancer (GC) is still unclear.

Materials and methods

We used Progression-free survival Kaplan-Meier analysis and Western blot analysis to detect the expression of GJB4 in GC tissues and cells. In addition, both in vitro and in vivo assays were used to determine the effect of GJB4 on malignant behavior in GC cells.

Results

We found that GJB4 was overexpressed in gastric cancer tissues and cells compared with normal tissues and cells. The high GJB4 expression was significantly associated with poor overall survival of GC patients. Knocking down GJB4 in GC cells significantly suppressed cell proliferation and migration. We found that the effects of GJB4-knockdown on GC cells were associated with downregulation of CTNNB1 and its downstream MYC, MMP7 and CCND1 expression. In addition, we found that the promotive effect of GJB4 overexpression on cell proliferation and migration was negated by XAV-939, which is the inhibitor of Wnt/CTNNB1 pathway. Therefore, we revealed a novel mechanism by which GJB4 could activate the Wnt/CTNNB1 pathway to promote GC cell's proliferation and migration.

Conclusion

This study offer insights into GJB4 function and indicate that GJB4 is a promising biomarker and therapeutic target for gastric cancer patients.

Clinical Implementation of Precision Medicine in Gastric Cancer

Gastric cancer (GC) is one of the deadliest malignancies in the world. Currently, clinical treatment decisions are mostly made based on the extent of the tumor and its anatomy, such as tumor-node-metastasis staging. Recent advances in genome-wide molecular technology have enabled delineation of the molecular characteristics of GC. Based on this, efforts have been made to classify GC into molecular subtypes with distinct prognosis and therapeutic response. Simplified algorithms based on protein and RNA expressions have been proposed to reproduce the GC classification in the clinical field. Furthermore, a recent study established a single patient classifier (SPC) predicting the prognosis and chemotherapy response of resectable GC patients based on a 4-gene real-time polymerase chain reaction assay. GC patient stratification according to SPC will enable personalized therapeutic strategies in adjuvant settings. At the same time, patient-derived xenografts and patient-derived organoids are now emerging as novel preclinical models for the treatment of GC. These models recapitulate the complex features of the primary tumor, which is expected to facilitate both drug development and clinical therapeutic decision making. An integrated approach applying molecular patient stratification and patient-derived models in the clinical realm is considered a turning point in precision medicine in GC.

[Expression of PSMA 7 and its effect on proliferation, invasion, migration and tumorigenesis of gastric cancer]

OBJECTIVE

To study the expression of PSMA7 and its effect on proliferation, invasion and migration of gastric cancer and subcutaneous tumorigenesis in nude mice. >and subcutaneous tumorigenesis in nude mice.

METHODS

Specimens of tumor tissues and paired adjacent tissues were collected from 60 patients with gastric cancer for detecting the expression levels of PSMA7 using immunohistochemical method. Gastric cancer cell line SGC7901 was transfected with a lentiviral vector to inhibit PSMA7 expression, and the changes in cell proliferation and invasion were observed using cell counting kit-8 (CCK-8), clone formation assay and Transwell assay. A BALB/c mouse model bearing subcutaneous gastric cancer xenograft was established using SGC7901 cells with stable PSMA7 knockdown to assess the effect of low expression of PSMA7 on xenograft growth.

RESULTS

Gastric cancer tissues expressed significantly higher levels of PSMA7 than the paired adjacent tissues (P < 0.05). In SGC7901 cells, interference of PSMA7 expression significantly inhibited the cell proliferation and invasion (P < 0.05). In the tumor-bearing BALB/c mice, the xenografts derived from SGC7901 cells with PSMA7 expression interference showed significant growth suppression as compared with the control xenografts (P < 0.05).

CONCLUSIONS

PPSMA 7 is overexpressed in gastric cancer tissues, and PSMA7 knockdown inhibits the proliferation, invasion, migration and subcutaneous tumorigenesis of gastric cancer cells in nude mice.

Polymorphisms in RAS/RAF/MEK/ERK Pathway Are Associated with Gastric Cancer

The RAS/RAF/MEK/ERK pathway regulates certain cellular functions, including cell proliferation, differentiation, survival, and apoptosis. Dysregulation of this pathway leads to the occurrence and progression of cancers mainly by somatic mutations. This study aimed to assess if polymorphisms of the RAS/RAF/MEK/ERK pathway are associated with gastric cancer. A case-control study of 242 gastric cancer patients and 242 controls was performed to assess the association of 27 single nucleotide polymorphisms (SNPs) in the RAS/RAF/MEK/ERK pathway genes with gastric cancer. Analyses performed under the additive model (allele) showed four significantly associated SNPs: RAF1 rs3729931 (Odds ratio (OR) = 1.54, 95%, confidence interval (CI): 1.20–1.98, p-value = 7.95 × 10⁻⁴), HRAS rs45604736 (OR = 1.60, 95% CI: 1.16–2.22, p-value = 4.68 × 10⁻³), MAPK1 rs2283792 (OR = 1.45, 95% CI: 1.12–1.87, p-value = 4.91 × 10⁻³), and MAPK1 rs9610417 (OR = 0.60, 95% CI: 0.42–0.87, p-value = 6.64 × 10⁻³). Functional annotation suggested that those variants or their proxy variants may have a functional effect. In conclusion, this study suggests that RAF1 rs3729931, HRAS rs45604736, MAPK1 rs2283792, and MAPK1 rs9610417 are associated with gastric cancer.

The combination of apatinib and S-1 for the treatment of advanced gastric cancer in China: A meta-analysis of randomized controlled trials

BACKGROUND

Apatinib-targeted therapy is considered a promising treatment option for malignancies. This study systematically evaluated the efficacy and safety of the combination of apatinib and S-1 for the treatment of patients with advanced gastric cancer (GC).

METHODS

Clinical trials were searched from the PubMed, Cochrane Library, Embase, CNKI, and Wanfang databases. Outcome measures including therapeutic efficacy, quality of life (QoL), and adverse events were extracted and evaluated.

RESULTS

Data from 8 trials including 393 patients with advanced GC were included. The results indicated that, compared with S-1 alone, the combination of apatinib with S-1 significantly improved patient partial response rate (odds ratio [OR] = 1.91, 95% confidence interval [CI] = 1.21-3.02, P = .005), overall response rate (ORR, OR = 2.40, 95% CI = 1.51-3.82, P = .0002), and disease control rate (DCR, OR = 2.78, 95% CI = 1.51-5.10, P = .0010), whereas the rates of complete response (CR, OR = 2.38, 95% CI = 0.93-6.12, P = .07) and stable disease (SD, OR = 0.99, 95% CI = 0.64-1.54, P = .97) and QoL (OR = 1.22, 95% CI = 0.51-2.92, P = .66) did not differ significantly. Moreover, the group receiving the combined therapy had higher rates of hand-foot syndrome (OR = 2.23, 95% CI = 1.19-4.17, P = .01), hypertension (OR = 8.85, 95% CI = 4.07-19.26, P < .00001), albuminuria (OR = 11.25, 95% CI = 3.32-38.06, P = .0001), and hemoglobin reduction (OR = 3.19, 95% CI = 1.32-7.67, P = .010), whereas analysis of other adverse events did not show significant differences (P > .05).

CONCLUSION

The combination of apatinib and S-1 is more effective for GC treatment than S-1 alone. However, this combined treatment could lead to increased hand-foot syndrome, hypertension, albuminuria, and hemoglobin reduction. Therefore, the benefits and risks should be considered before treatment.

Never-in-mitosis A-related kinase 8, a novel target of von-Hippel-Lindau tumor suppressor protein, promotes gastric cancer cell proliferation

Previous research has revealed that the von-Hippel-Lindau tumor suppressor protein (pVHL) may downregulate never-in-mitosis A-related kinase 8 (NEK8) via hypoxia-inducible factor-α (HIF-α). The HIF-independent functions of pVHL also serve an important role in its tumor-suppressor action. In the present study, the association between pVHL and NEK8 was demonstrated in the human gastric cancer cell line, SGC-7901, indicating a direct interaction of pVHL with NEK8. Subsequently, it was reported that MG-132, a specific proteasome inhibitor, may attenuate pVHL overexpression-induced reductions in NEK8 protein expression levels. In addition, the present study revealed that pVHL may stimulate the rapid degradation of NEK8 protein and promote its ubiquitination. The association between the expression profile of NEK8 and the survival status of patients with gastric cancer was analyzed from an online database. Kaplan-Meier survival plots indicated that higher expression levels of NEK8 may lead to poor survival, as suggested by the transcriptomic data of 1,065 patients with gastric cancer. It was found that NEK8-knockdown mediated by RNA interference inhibited SGC-7901 and SNU-1 proliferation, colony formation and migration in vitro, and tumor growth in vivo. Collectively, the present study proposed that NEK8 may be a novel target of pVHL as a ubiquitin E3 ligase, and may serve a role as a potential oncoprotein in human gastric cancer.

Novel prognostic biomarkers of gastric cancer based on gene expression microarray: COL12A1, GSTA3, FGA and FGG

Gastric cancer (GC) is the fifth most common malignancy and the third leading cause of cancer-associated mortality in the world. However, its mechanisms of occurrence and development have not been clearly elucidated. Furthermore, there is no effective tumor marker for GC. Using DNA microarray analysis, the present study revealed genetic alterations, screened out core genes as novel markers and discovered pathways for potential therapeutic targets. Differentially expressed genes (DEGs) between GC and adjacent normal tissues were identified, followed by pathway enrichment analysis of DEGs. Next, the protein-protein interaction (PPI) network of DEGs was built and visualized. Analyses of modules in the PPI network were then performed to identify the functional core genes. Finally, survival analysis of core genes was conducted. A total of 256 genes were identified as DEGs between the GC samples and normal samples, including 169 downregulated and 87 upregulated genes. Through Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis, the present study identified a total of 143 GO terms and 21 pathways. Six clusters of functional modules were identified, and the genes associated with these modules were screened out as the functional core genes. Certain core genes, including collagen type 12 α1 chain (COL12A1), glutathione S-transferase α3 (GSTA3), fibrinogen α chain (FGA) and fibrinogen γ chain (FGG), were the first reported to be associated with GC. Survival analysis suggested that these four genes, COL12A1 (P=0.002), GSTA3 (P=3.4×10⁻⁶), FGA (P=0.00075) and FGG (P=1.4×10-5), were significant poor prognostic factors and therefore, potential targets to improve diagnosis, optimize chemotherapy and predict prognostic outcomes.

Disappearance of bone metastases in chemotherapy-resistant gastric cancer treated with antigen peptide-pulsed dendritic cell-activated cytotoxic T lymphocyte immunotherapy: A case report

The adoptive transfer of cytotoxic T lymphocytes (CTLs) stimulated by specific tumor antigen peptide-pulsed dendritic cells (DCs) is one of the most promising immunotherapeutic strategies currently available for patients with gastric cancer (GC). The present case report describes a patient with chemotherapy-resistant stage IV GC with multiple bone metastases, who had been treated with antigen peptide-pulsed DC-CTLs. DCs and CTLs were transfused into the patient subcutaneously and intravenously with simultaneous oral administration of low-dose cyclophosphamide. Following 3 cycles of combination therapy, marked remission regarding the number of metastatic bone lesions was achieved, confirmed by the use of enhanced computerized tomography, computerized tomography and magnetic resonance imaging. After 1 year, 8 cycles of adoptive immunotherapy were administered, and a further decrease in the number of metastatic bone lesions was observed in addition to a marked improvement in the patient's quality of life. Therefore, personalized antigen peptide-pulsed DC-CTLs combined with oral administration of low-dose cyclophosphamide may serve as a promising anticancer therapy to eradicate tumor cells, and therefore this approach is recommended for future cases of a similar nature.