Gastric Tumor Microenvironment

The extracellular matrix protein EMILIN-1 impacts on the microenvironment by hampering gastric cancer development and progression

BACKGROUND

The contribution of the tumor microenvironment and extracellular matrix to the aggressive biology of Gastric Cancer (GC) has been recently characterized; however, the role of EMILIN-1 in this context is unknown. EMILIN-1 is an essential structural element for the maintenance of lymphatic vessel (LV) integrity and displays anti-proliferative properties as demonstrated in skin and colon cancer. Given the key role of LVs in GC progression, the aim of this study was to investigate the role of EMILIN-1 in GC mouse models.

METHODS

We used the syngeneic YTN16 cells which were injected subcutaneously and intraperitoneally in genetically modified EMILIN-1 mice. In alternative, carcinogenesis was induced using N-Methyl-N-nitrosourea (MNU). Mouse-derived samples and human biopsies were analyzed by IHC and IF to the possible correlation between EMILIN-1 expression and LV pattern.

RESULTS

Transgenic mice developed tumors earlier compared to WT animals. 20 days post-injection tumors developed in EMILIN-1 mutant mice were larger and displayed a significant increase of lymphangiogenesis. Treatment of transgenic mice with MNU associated with an increased number of tumors, exacerbated aggressive lesions and higher levels of LV abnormalities. A significant correlation between the levels of EMILIN-1 and podoplanin was detected also in human samples, confirming the results obtained with the pre-clinical models.

CONCLUSIONS

This study demonstrates for the first time that loss of EMILIN-1 in GC leads to lymphatic dysfunction and proliferative advantages that sustain tumorigenesis, and assess the use of our animal model as a valuable tool to verify the fate of GC upon loss of EMILIN-1.

Tumor microenvironment characteristics of lipid metabolism reprogramming related to ferroptosis and EndMT influencing prognosis in gastric cancer

BACKGROUND

Gastric cancer (GC) is a refractory malignant tumor with high tumor heterogeneity, a low rate of early diagnosis, and poor patient prognosis. Lipid metabolism reprogramming plays a critical role in tumorigenesis and progression, but its prognostic role and regulatory mechanism in GC are rarely studied. Thus, the identification of signatures related to lipid metabolism is necessary and may present a new avenue for improving the overall prognosis of GC.

METHODS

Lipid metabolism-associated genes (LMAGs) with differential expression in tumor and tumor-adjacent tissue were acquired to identify lipid metabolism-associated subtypes. The differentially expressed genes (DEGs) between the two clusters were then utilized for prognostic analysis and signature construction. Additionally, pathway enrichment analysis and immune cell infiltration analysis were employed to identify the characteristics of the prognostic model. Further analyses were conducted at the single-cell level to better understand the model's prognostic mechanism. Finally, the prediction of immunotherapy response was used to suggest potential treatments.

RESULTS

Two lipid metabolism-associated subtypes were identified and 9 prognosis-related genes from the DEGs between the two clusters were collected for the construction of the prognostic model named lipid metabolism-associated signature (LMAS). Then we found the low LMAS patients with favorable prognoses were more sensitive to ferroptosis in the Cancer Genome Atlas of Stomach Adenocarcinoma (TCGA-STAD). Meanwhile, the tumor cells exhibiting high levels of lipid peroxidation and accumulation of reactive oxygen species (ROS) in single-cell levels were primarily enriched in the low LMAS group, which was more likely to induce ferroptosis. In addition, endothelial cells and cancer-associated fibroblasts (CAFs) facilitated tumor angiogenesis, proliferation, invasion, and metastasis through endothelial-mesenchymal transition (EndMT), affecting the prognosis of the patients with high LMAS scores. Moreover, CD1C- CD141- dendritic cells (DCs) also secreted pro-tumorigenic cytokines to regulate the function of endothelial cells and CAFs. Finally, the patients with low LMAS scores might have better efficacy in immunotherapy.

CONCLUSIONS

A LMAS was constructed to guide GC prognosis and therapy. Meanwhile, a novel anti-tumor effect was found in lipid metabolism reprogramming of GC which improved patients' prognosis by regulating the sensitivity of tumor cells to ferroptosis. Moreover, EndMT may have a negative impact on GC prognosis.

TREM1 facilitates the development of gastric cancer through regulating neutrophil extracellular traps-mediated macrophage polarization

Triggering receptor expressed on myeloid cell 1 (TREM1) elevation is associated with the unfavorable prognosis of gastric cancer (GC) patients. This work uncovered the effects and mechanism of TREM1 in GC. IHC staining examined TREM1 expression in GC tissues. TREM1-knockout and TREM1 knock-in mice were generated prior to the construction of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG)-induced GC mice model. H&E staining detected the pathological alternations of gastric tissues. IHC staining tested Ki67 expression. Wright-Giemsa staining performed neutrophil counting and flow cytometry analysis measured neutrophil infiltration. ELISA analyzed serum and tissue myeloperoxidase (MPO) levels and serum MPO-DNA levels. Immunofluorescence, Western blotting and related kits detected NETs formation. Immunofluorescence and IHC staining evaluated macrophage polarization. In MNNG-treated GES-1 cells and phorbal myristate acetate (PMA)-treated neutrophils, TREM1 expression was also examined. CCK-8 method and Western blotting assayed cell proliferation. Western blotting and immunofluorescence detected NETs formation. Flow cytometry analysis detected the changes of macrophage typing. TREM1 was overexpressed in tumor tissues, MNNG-treated GES-1 cells and PMA-treated neutrophils. TREM1 deficiency hindered tumor growth, reduced neutrophil infiltration, NETs formation and stimulated M1 macrophage polarization in MNNG-induced GC models. Neutrophil extracellular traps (NETs) degrader DNase-1 countervailed the impacts of TREM1 on MNNG-induced GC models in vivo. Collectively, TREM1 knockdown obstructed NETs-mediated M2 macrophage polarization to hamper GC progression.

A comprehensive analysis of GAS2 family members identifies that GAS2L1 is a novel biomarker and promotes the proliferation of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a common primary liver cancer with a high incidence and mortality. Members of the growth-arresting-specific 2 (GAS2) family are involved in various biological processes in human malignancies. To date, there is only a limited amount of information available about the expression profile and clinical importance of GAS2 family in HCC. In this study, we found that GAS2L1 and GAS2L3 were distinctly upregulated in HCC specimens compared to non-tumor specimens. Pan-cancer assays indicated that GAS2L1 and GAS2L3 were highly expressed in most cancers. The Pearson's correlation revealed that the expressions of GAS2, GAS2L1 and GAS2L2 were negatively associated with methylation levels. Survival assays indicated that GAS2L1 and GAS2L3 were independent prognostic factors for HCC patients. Immune cell infiltration analysis revealed that GAS2, GAS2L1 and GAS2L3 were associated with several immune cells. Finally, we confirmed that GAS2L1 was highly expressed in HCC cells and its knockdown suppressed the proliferation of HCC cells. Taken together, our findings suggested the expression patterns and prognostic values of GAS2 members in HCC, providing insights for further study of the GAS2 family as sensitive diagnostic and prognostic markers for HCC.

Comprehensive analysis of peroxisome proliferator-activated receptors to predict the drug resistance, immune microenvironment, and prognosis in stomach adenocarcinomas

Background

Peroxisome proliferator-activated receptors (PPARs) exert multiple functions in the initiation and progression of stomach adenocarcinomas (STAD). This study analyzed the relationship between PPARs and the immune status, molecular mutations, and drug therapy in STAD.

Methods

The expression profiles of three PPAR genes (PPARA, PPARD and PPARG) were downloaded from The Cancer Genome Atlas (TCGA) dataset to analyze their expression patterns across pan-cancer. The associations between PPARs and clinicopathologic features, prognosis, tumor microenvironment, genome mutation and drug sensitivity were also explored. Co-expression between two PPAR genes was calculated using Pearson analysis. Regulatory pathways of PPARs were scored using gene set variation analysis (GSVA) package. Quantitative real-time polymerase chain reaction (qRT-PCR), Western blot, Cell Counting Kit-8 (CCK-8) assay and transwell assay were conducted to analyze the expression and function of the PPAR genes in STAD cell lines (AGS and SGC7901 cells).

Results

PPARA, PPARD and PPARG were more abnormally expressed in STAD samples and cell lines when compared to most of 32 type cancers in TCGA. In STAD, the expression of PPARD was higher in Grade 3+4 and male patients, while that of PPARG was higher in patient with Grade 3+4 and age > 60. Patients in high-PPARA expression group tended to have longer survival time. Co-expression analysis revealed 6 genes significantly correlated with the three PPAR genes in STAD. Single-sample GSEA (ssGSEA) showed that the three PPAR genes were enriched in 23 pathways, including MITOTIC_SPINDLE, MYC_TARGETS_V1, E2F_TARGETS and were closely correlated with immune cells, including NK_cells_resting, T_cells_CD4_memory_resting, and macrophages_M0. Immune checkpoint genes (CD274, SIGLEC15) were abnormally expressed between high-PPAR expression and low-PPAR expression groups. TTN, MUC16, FAT2 and ANK3 genes had a high mutation frequency in both high-PPARA/PPARG and low-PPARA/PPARG expression group. Fourteen and two PPARA/PPARD drugs were identified to be able to effectively treat patients in high-PPARA/PPARG and low-PPARA/PPARG expression groups, respectively. We also found that the chemotherapy drug Vinorelbine was positively correlated with the three PPAR genes, showing the potential of Vinorelbine to serve as a treatment drug for STAD. Furthermore, cell experiments demonstrated that PPARG had higher expression in AGS and SGC7901 cells, and that inhibiting PPARG suppressed the viability, migration and invasion of AGS and SGC7901 cells.

Conclusions

The current results confirmed that the three PPAR genes (PPARA, PPARD and PPARG) affected STAD development through mediating immune microenvironment and genome mutation.

Clinical Significance and Immune Infiltration Analyses of a Novel Nerve-Related lncRNA Signature in Gastric Cancer

Gastric cancer (GC) is a progressive disease with high morbidity and mortality. Accumulating evidence indicated that nervous system-cancer crosstalk can affect the occurrence and progression of GC. However, the role of nerve-related lncRNAs (NRLs) in GC remains largely unexplored. In this study, a total of 441 nerve-related genes were collected from the KEGG database, and two approaches, unsupervised clustering and WGCNA, were employed to identify NRLs. Lasso regression analysis was then used to construct the nerve-related lncRNA signature (NRLS). Based on the expression profiles of 5 lncRNAs, we developed a stable NRLS to predict survival in GC patients, and survival analyses showed significantly shorter overall survival (OS) in patients with high NRLS. In addition, the NRLS was found to be positively correlated with immune characteristics, including tumor-infiltrating immune cells, immune modulators, cytokines and chemokines. We then analyzed the role of NRLS in predicting chemotherapy and immunotherapy responses, and constructed the OS nomogram combining NRLS and other clinical features. In conclusion, we constructed a robust NRLS model to stratify GC patients and predict the outcomes of chemotherapy and immunotherapy. This study can provide a new perspective for future individualized treatment of GC.

Metabolic reprogramming involves in transition of activated/resting CD4+ memory T cells and prognosis of gastric cancer

Background

Little is known on how metabolic reprogramming potentially prompts transition of activated and resting CD4+ memory T cells infiltration in tumor microenvironment of gastric cancer (GC). The study aimed to evaluate their interactions and develop a risk model for predicting prognosis in GC.

Methods

Expression profiles were obtained from TCGA and GEO databases. An immunotherapeutic IMvigor210 cohort was also enrolled. CIBERSORT algorithm was used to evaluate the infiltration of immune cells. The ssGSEA method was performed to assess levels of 114 metabolism pathways. Prognosis and correlation analysis were conducted to identify metabolism pathways and genes correlated with activated CD4+ memory T cells ratio (AR) and prognosis. An AR-related metabolism gene (ARMG) risk model was constructed and validated in different cohorts. Flow cytometry was applied to validate the effect of all-trans retinoic acid (ATRA) on CD4+ memory T cells.

Results

Since significantly inverse prognostic value and negative correlation of resting and activated CD4+ memory T cells, high AR level was associated with favorable overall survival (OS) in GC. Meanwhile, 15 metabolism pathways including retinoic acid metabolism pathway were significantly correlated with AR and prognosis. The ARMG risk model could classify GC patients with different outcomes, treatment responses, genomic and immune landscape. The prognostic value of the model was also confirmed in the additional validation, immunotherapy and pan-cancer cohorts. Functional analyses revealed that the ARMG model was positively correlated with pro-tumorigenic pathways. In vitro experiments showed that ATRA could inhibit levels of activated CD4+ memory T cells and AR.

Conclusion

Our study showed that metabolic reprogramming including retinoic acid metabolism could contribute to transition of activated and resting CD4+ memory T cells, and affect prognosis of GC patients. The ARMG risk model could serve as a new tool for GC patients by accurately predicting prognosis and response to treatment.

Integrative analysis of cancer-associated fibroblast signature in gastric cancer

Background

CAFs regulate the signaling of GC cells by promoting their migration, invasion, and proliferation and the function of immune cells as well as their location and migration in the TME by remodeling the extracellular matrix (ECM). This study explored the understanding of the heterogeneity of CAFs in TME and laid the groundwork for GC biomarker and precision treatment development.

Methods

The scRNA-seq and bulk RNA-seq datasets were obtained from GEO and TCGA. The prognostic significance of various CAFs subtypes was investigated using ssGSEA combined with Kaplan-Meier analysis. POSTN expression in GC tissues and CAFs was detected using immunohistochemistry, immunofluorescence, and Western blotting. Differential expression analysis identified the differentially expressed genes (DEGs) between normal and tumor samples in TCGA-STAD. Pearson correlation analysis identified DEGs associated with adverse prognosis CAF subtype, and univariate Cox regression analysis determined prognostic genes associated with CAFs. LASSO regression analysis and Multivariate Cox regression were used to build a prognosis model for CAFs.

Results

We identified five CAFs subtypes in GC, with the CAF_0 subtype associated with poor prognosis. The abundance of CAF_0 correlated with T stage, clinical stage, histological type, and immune cell infiltration levels. Periostin (POSTN) exhibited increased expression in both GC tissues and CAFs and was linked to poor prognosis in GC patients. Through LASSO and multivariate Cox regression analysis, three genes (CXCR4, MATN3, and KIF24) were selected to create the CAFs-score. We developed a nomogram to facilitate the clinical application of the CAFs-score. Notably, the CAFs signature showed significant correlations with immune cells, stromal components, and immunological scores, suggesting its pivotal role in the tumor microenvironment (TME). Furthermore, CAFs-score demonstrated prognostic value in assessing immunotherapy outcomes, highlighting its potential as a valuable biomarker to guide therapeutic decisions.

Conclusion

CAF_0 subtype in TME is the cause of poor prognosis in GC patients. Furthermore, CAFs-score constructed from the CAF_0 subtype can be used to determine the clinical prognosis, immune infiltration, clinicopathological characteristics, and assessment of personalized treatment of GC patients.

Two web-based dynamic prediction models for the diagnosis and prognosis of gastric cancer with bone metastases: evidence from the SEER database

Purpose

Our aim was to identify the clinical characteristics and develop and validate diagnostic and prognostic web-based dynamic prediction models for gastric cancer (GC) with bone metastasis (BM) using the SEER database.

Method

Our study retrospectively analyzed and extracted the clinical data of patients aged 18-85 years who were diagnosed with gastric cancer between 2010 and 2015 in the SEER database. We randomly divided all patients into a training set and a validation set according to the ratio of 7 to 3. Independent factors were identified using logistic regression and Cox regression analyses. Furthermore, we developed and validated two web-based clinical prediction models. We evaluated the prediction models using the C-index, ROC, calibration curve, and DCA.

Result

A total of 23,156 patients with gastric cancer were included in this study, of whom 975 developed bone metastases. Age, site, grade, T stage, N stage, brain metastasis, liver metastasis, and lung metastasis were identified as independent risk factors for the development of BM in GC patients. T stage, surgery, and chemotherapy were identified as independent prognostic factors for GC with BM. The AUCs of the diagnostic nomogram were 0.79 and 0.81 in the training and test sets, respectively. The AUCs of the prognostic nomogram at 6, 9, and 12 months were 0.93, 0.86, 0.78, and 0.65, 0.69, 0.70 in the training and test sets, respectively. The calibration curve and DCA showed good performance of the nomogram.

Conclusions

We established two web-based dynamic prediction models in our study. It could be used to predict the risk score and overall survival time of developing bone metastasis in patients with gastric cancer. In addition, we also hope that these two web-based applications will help physicians comprehensively manage gastric cancer patients with bone metastases.

Development of a novel copper metabolism-related risk model to predict prognosis and tumor microenvironment of patients with stomach adenocarcinoma

Background: Stomach adenocarcinoma (STAD) is the fourth highest cause of cancer mortality worldwide. Alterations in copper metabolism are closely linked to cancer genesis and progression. We aim to identify the prognostic value of copper metabolism-related genes (CMRGs) in STAD and the characteristic of the tumor immune microenvironment (TIME) of the CMRG risk model. Methods: CMRGs were investigated in the STAD cohort from The Cancer Genome Atlas (TCGA) database. Then, the hub CMRGs were screened out with LASSO Cox regression, followed by the establishment of a risk model and validated by GSE84437 from the Expression Omnibus (GEO) database. The hub CMRGs were then utilized to create a nomogram. TMB (tumor mutation burden) and immune cell infiltration were investigated. To validate CMRGs in immunotherapy response prediction, immunophenoscore (IPS) and IMvigor210 cohort were employed. Finally, data from single-cell RNA sequencing (scRNA-seq) was utilized to depict the properties of the hub CMRGs. Results: There were 75 differentially expressed CMRGs identified, 6 of which were linked with OS. 5 hub CMRGs were selected by LASSO regression, followed by construction of the CMRG risk model. High-risk patients had a shorter life expectancy than those low-risk. The risk score independently predicted STAD survival through univariate and multivariate Cox regression analyses, with ROC calculation generating the highest results. This risk model was linked to immunocyte infiltration and showed a good prediction performance for STAD patients' survival. Furthermore, the high-risk group had lower TMB and somatic mutation counters and higher TIDE scores, but the low-risk group had greater IPS-PD-1 and IPS-CTLA4 immunotherapy prediction, indicating a higher immune checkpoint inhibitors (ICIs) response, which was corroborated by the IMvigor210 cohort. Furthermore, those with low and high risk showed differential susceptibility to anticancer drugs. Based on CMRGs, two subclusters were identified. Cluster 2 patients had superior clinical results. Finally, the copper metabolism-related TIME of STAD was concentrated in endothelium, fibroblasts, and macrophages. Conclusion: CMRG is a promising biomarker of prognosis for patients with STAD and can be used as a guide for immunotherapy.

Ferroptosis-Related lncRNAs Act as Novel Prognostic Biomarkers in the Gastric Adenocarcinoma Microenvironment, Immunotherapy, and Chemotherapy

Ferroptosis, a form of programmed cell death akin to necrosis, is managed by iron and is distinguished by lipid peroxidation. Gastric cancer is a highly aggressive form of cancer, responsible for the third highest number of cancer-related deaths globally. Despite this, the potential of ferroptosis to predict the occurrence of this cancer is yet to be determined. In this research, a comprehensive examination was conducted to explore the link between long noncoding RNAs (lncRNAs) and ferroptosis, in order to uncover an lncRNA signature that can predict drug susceptibility and tumor mutational burden (TMB) in gastric adenocarcinoma. We conducted an in-depth analysis of the GC immune microenvironment and immunotherapy, with a particular focus on ferroptosis-related lncRNA prognostic biomarkers, and further explored the correlation between these factors and prognosis, immune infiltration, single nucleotide variation (SNV), and drug sensitivity for gastric adenocarcinoma patients. Through our investigations, we have discovered five lncRNA signatures related to ferroptosis that can accurately forecast the prognosis of gastric adenocarcinoma patients and also regulate the proliferation, migration, and occurrence of ferroptosis in gastric adenocarcinoma cells. In conclusion, this lncRNA signature associated with ferroptosis may be employed as a prognostic indicator for gastric adenocarcinoma, thus presenting a potential solution.

Construction of a hypoxia-immune-related prognostic panel based on integrated single-cell and bulk RNA sequencing analyses in gastric cancer

Introduction

Gastric cancer (GC) is the fifth most common tumor, contributing to the third-highest number of cancer-related deaths. Hypoxia is a major feature of the tumor microenvironment. This study aimed to explore the influence of hypoxia in GC and establish a hypoxia-related prognostic panel.

Methods

The GC scRNA-seq data and bulk RNA-seq data were downloaded from the GEO and TCGA databases, respectively. AddModuleScore() and AUCell() were used to calculate module scores and fractions of enrichment for hypoxia-related gene expression in single cells. Least absolute shrinkage and selection operator cox (LASSO-COX) regression analysis was utilized to build a prognostic panel, and hub RNAs were validated by qPCR. The CIBERSORT algorithm was adopted to evaluate immune infiltration. The finding of immune infiltration was validated by a dual immunohistochemistry staining. The TIDE score, TIS score and ESTIMATE were used to evaluate the immunotherapy predictive efficacy.

Results

Hypoxia-related scores were the highest in fibroblasts, and 166 differentially expressed genes were identified. Five hypoxia-related genes were incorporated into the hypoxia-related prognostic panel. 4 hypoxia-related genes (including POSTN, BMP4, MXRA5 and LBH) were significantly upregulated in clinical GC samples compared with the normal group, while APOD expression decreased in GC samples. Similar results were found between cancer-associated fibroblasts (CAFs) and normal fibroblasts (NFs). A high hypoxia score was associated with advanced grade, TNM stage, N stage, and poorer prognosis. Decreased antitumor immune cells and increased cancer-promoting immune cells were found in patients with high hypoxia scores. Dual immunohistochemistry staining showed high expression of CD8 and ACTA2 in gastric cancer tissue. In addition, the high hypoxia score group possessed higher TIDE scores, indicating poor immunotherapy benefit. A high hypoxia score was also firmly related to sensitivity to chemotherapeutic drugs.

Discussion

This hypoxia-related prognostic panel may be effective in predicting the clinical prognosis, immune infiltrations, immunotherapy, and chemotherapy in GC.

Novel m7G-related lncRNA signature for predicting overall survival in patients with gastric cancer

Presenting with a poor prognosis, gastric cancer (GC) remains one of the leading causes of disease and death worldwide. Long non-coding RNAs (lncRNAs) regulate tumor formation and have been long used to predict tumor prognosis. N7-methylguanosine (m7G) is the most prevalent RNA modification. m7G-lncRNAs regulate GC onset and progression, but their precise mechanism in GC is unclear. The objective of this research was the development of a new m7G-related lncRNA signature as a biomarker for predicting GC survival rate and guiding treatment. The Cancer Genome Atlas database helped extract gene expression data and clinical information for GC. Pearson correlation analysis helped point out m7G-related lncRNAs. Univariate Cox analysis helped in identifying m7G-related lncRNA with predictive capability. The Lasso-Cox method helped point out seven lncRNAs for the purpose of establishing an m7G-related lncRNA prognostic signature (m7G-LPS), followed by the construction of a nomogram. Kaplan-Meier analysis, univariate and multivariate Cox regression analysis, calibration plot of the nomogram model, receiver operating characteristic curve and principal component analysis were utilized for the verification of the risk model's reliability. Furthermore, q-PCR helped verify the lncRNAs expression of m7G-LPS in-vitro. The study subjects were classified into high and low-risk groups based on the median value of the risk score. Gene enrichment analysis confirmed the constructed m7G-LPS' correlation with RNA transcription and translation and multiple immune-related pathways. Analysis of the clinicopathological features revealed more progressive features in the high-risk group. CIBERSORT analysis showed the involvement of m7G-LPS in immune cell infiltration. The risk score was correlated with immune checkpoint gene expression, immune cell and immune function score, immune cell infiltration, and chemotherapy drug sensitivity. Therefore, our study shows that m7G-LPS constructed using seven m7G-related lncRNAs can predict the survival time of GC patients and guide chemotherapy and immunotherapy regimens as biomarker.

Contributions of the receptor for advanced glycation end products axis activation in gastric cancer

Compelling shreds of evidence derived from both clinical and experimental research have demonstrated the crucial contribution of receptor for advanced glycation end products (RAGE) axis activation in the development of neoplasms, including gastric cancer (GC). This new actor in tumor biology plays an important role in the onset of a crucial and long-lasting inflammatory milieu, not only by supporting phenotypic changes favoring growth and dissemination of tumor cells, but also by functioning as a pattern-recognition receptor in the inflammatory response to Helicobacter pylori infection. In the present review, we aim to highlight how the overexpression and activation of the RAGE axis contributes to the proliferation and survival of GC cells as and their acquisition of more invasive phenotypes that promote dissemination and metastasis. Finally, the contribution of some single nucleotide polymorphisms in the RAGE gene as susceptibility or poor prognosis factors is also discussed.

CD93 serves as a potential biomarker of gastric cancer and correlates with the tumor microenvironment

BACKGROUND

The tumor microenvironment (TME) plays an important role in the growth and expansion of gastric cancer (GC). Studies have identified that CD93 is involved in abnormal tumor angiogenesis, which may be related to the regulation of the TME.

AIM

To determine the role of CD93 in GC.

METHODS

Transcriptomic data of GC was investigated in a cohort from The Cancer Genome Atlas. Additionally, RNA-seq data sets from Gene Expression Omnibus (GSE118916, GSE52138, GSE79973, GSE19826, and GSE84433) were applied to validate the results. We performed the immune infiltration analyses using ESTIMATE, CIBERSORT, and ssGSEA. Furthermore, weighted gene co-expression network analysis (WGCNA) was conducted to identify the immune-related genes.

RESULTS

Compared to normal tissues, CD93 significantly enriched in tumor tissues (t = 4.669, 95%CI: 0.342-0.863, P < 0.001). Higher expression of CD93 was significantly associated with shorter overall survival (hazard ratio = 1.62, 95%CI: 1.09-2.4, P = 0.017), less proportion of CD8 T and activated natural killer cells in the TME (P < 0.05), and lower tumor mutation burden (t = 4.131, 95%CI: 0.721-0.256, P < 0.001). Genes co-expressed with CD93 were mainly enriched in angiogenesis. Moreover, 11 genes were identified with a strong relationship between CD93 and the immune microenvironment using WGCNA.

CONCLUSION

CD93 is a novel prognostic and diagnostic biomarker for GC, that is closely related to the immune infiltration in the TME. Although this retrospective study was a comprehensive analysis, the prospective cohort studies are preferred to further confirm these conclusions.

An Update of G-Protein-Coupled Receptor Signaling and Its Deregulation in Gastric Carcinogenesis

G-protein-coupled receptors (GPCRs) belong to a cell surface receptor superfamily responding to a wide range of external signals. The binding of extracellular ligands to GPCRs activates a heterotrimeric G protein and triggers the production of numerous secondary messengers, which transduce the extracellular signals into cellular responses. GPCR signaling is crucial and imperative for maintaining normal tissue homeostasis. High-throughput sequencing analyses revealed the occurrence of the genetic aberrations of GPCRs and G proteins in multiple malignancies. The altered GPCRs/G proteins serve as valuable biomarkers for early diagnosis, prognostic prediction, and pharmacological targets. Furthermore, the dysregulation of GPCR signaling contributes to tumor initiation and development. In this review, we have summarized the research progress of GPCRs and highlighted their mechanisms in gastric cancer (GC). The aberrant activation of GPCRs promotes GC cell proliferation and metastasis, remodels the tumor microenvironment, and boosts immune escape. Through deep investigation, novel therapeutic strategies for targeting GPCR activation have been developed, and the final aim is to eliminate GPCR-driven gastric carcinogenesis.

An integrative pan-cancer analysis reveals the carcinogenic effects of NCAPH in human cancer

BACKGROUND

Non-chromosomal structure maintenance protein condensin complex I subunit H (NCAPH) has been reported to play a regulatory role in a variety of cancers and is associated with tumor poor prognosis. This study aims to explore the potential role of NCAPH with a view to providing insights on pathologic mechanisms.

METHODS

The expression of NCAPH in different tumors was explored by The Cancer Genome Atlas (TCGA) and Genotype Tissue Expression (GTEx). The prognostic value of NCAPH was retrieved through GEPIA and Kaplan-Meier Plotter databases. Tumor Immunity Estimation Resource (TIMER) and Single-Sample Gene Set Enrichment Analysis (GSEA) to search for the association of NCAPH with tumor immune infiltration. The cBioPortal and PhosphoSite Plus databases showed NCAPH phosphorylation status in tumors. Gene set enrichment analysis (GSEA) was performed using bioinformatics.

RESULTS

Our findings revealed that NCAPH showed high expression levels in a wide range of tumor types, and was strongly correlated with the prognosis of patients. Moreover, a higher phosphorylation level at S59, S67, S76, S190, S222 and T38 site was discovered in head and neck squamous cell carcinoma (HNSC). NCAPH overexpression was positively correlated with the infiltration level of CD8+T cells and myeloid dendritic infiltration in breast cancer and thymoma.

CONCLUSIONS

The up-regulation of NCAPH was significantly correlated with the poor prognosis and immune infiltration in pan-cancer, and NCAPH could be served as a potential immunotherapeutic target for cancers.

Cancer-associated fibroblasts, and clinicopathological characteristics and prognosis of gastric cancer: A systematic review and meta-analysis

Objective

To systematically evaluate the relationship between cancer-associated fibroblasts (CAFs) and clinicopathological characteristics and prognosis of gastric cancer, so as to provide new directions and clinical evidence for the diagnosis and treatment of this disease.

Methods

We searched PubMed, Embase, Web of Science, and The Cochrane Library to identify studies on the correlation between tumor-associated fibroblasts and the diagnosis and prognosis of gastric cancer. Two researchers screened the literature independently to extract data, evaluated the quality of the included studies, and used the Review Manager 5.4 software to perform a meta-analysis.

Results

A total of 14 studies involving a total of 2,703 patients were included. The meta-analysis results showed that high expression of CAFs was associated with stage III-IV gastric cancer (relative risk ratio [RR]=1.59; 95% confidence interval [CI]: [1.24-2.04]; P=0.0003), lymph node metastasis (RR=1.51; 95% CI: [1.23-1.87]; P=0.0001), serosal infiltration (RR=1.56, 95% CI: [1.24-1.95]; P=0.0001), diffuse and mixed types in Lauren classification (RR=1.43; 95% CI: [1.18-1.74]; P=0.0003), vascular invasion (RR=1.99; 95% CI: [1.26-3.14]; P=0.003), and overall survival (hazard ratio [HR]=1.38; 95% CI: [1.22-1.56]; P<0.00001). However, the high expression of CAFs was not significantly correlated with poorly differentiated gastric cancer (RR=1.03; 95% CI: [0.96-1.10]; P=0.45) and gastric cancer with tumor diameter >5 cm (RR=1.34; 95% CI: [0.98-1.83]; P=0.07).

Conclusion

The findings of this meta-analysis demonstrated that high expression of CAFs is closely associated with the traditional pathological indicators related to poor prognosis in gastric cancer, and is a valuable prognostic factor in this setting.

Systematic Review Registration

https://www.crd.york.ac.uk/PROSPERO/, identifier CRD42022358165.

TRIM44 regulates tumor immunity in gastric cancer through LOXL2-dependent extracellular matrix remodeling

PURPOSE

Gastric cancer is a gastrointestinal malignancy with high mortality and poor prognosis, and the molecular mechanism of gastric tumorigenesis remains unclear. TRIM44 has been reported to be involved in tumor development. However, the role of TRIM44 in tumor immunity is largely unknown.

METHODS

We analyzed TRIM44 expression in clinical gastric cancer tissues and normal tissues by using western blot, quantitative real-time PCR and bioinformatics analyses. We further investigated the involvement of TRIM44 in tumor immunity in vivo and found that it was dependent on extracellular matrix remodeling. We detected the interaction between TRIM44 and LOXL2 by using immunofluorescence staining and coimmunoprecipitation assays. We observed that TRIM44 mediates the stability of LOXL2 by ubiquitination assays.

RESULTS

TRIM44 expression is high and is correlated with T-cell infiltration in gastric cancer. TRIM44 inhibits gastric tumorigenicity by regulating T-cell-mediated antitumor immunity and modulating the protein level of LOXL2. Mechanistically, TRIM44 directly binds to LOXL2 and affects the stability of LOXL2 to change extracellular matrix remodeling and influence tumor immunity.

CONCLUSION

These findings demonstrate that TRIM44 regulates the stability of LOXL2 to remodel the tumor extracellular matrix to modulate tumor immunity in gastric cancer and that the TRIM44/LOXL2 complex is a promising biomarker for gastric cancer prognosis and might be a novel immunotherapy target.

Machine learning-based identification of a novel prognosis-related long noncoding RNA signature for gastric cancer

Gastric cancer (GC) is one of the most common malignancies with a poor prognosis. Immunotherapy has attracted much attention as a treatment for a wide range of cancers, including GC. However, not all patients respond to immunotherapy. New models are urgently needed to accurately predict the prognosis and the efficacy of immunotherapy in patients with GC. Long noncoding RNAs (lncRNAs) play crucial roles in the occurrence and progression of cancers. Recent studies have identified a variety of prognosis-related lncRNA signatures in multiple cancers. However, these studies have some limitations. In the present study, we developed an integrative analysis to screen risk prediction models using various feature selection methods, such as univariate and multivariate Cox regression, least absolute shrinkage and selection operator (LASSO), stepwise selection techniques, subset selection, and a combination of the aforementioned methods. We constructed a 9-lncRNA signature for predicting the prognosis of GC patients in The Cancer Genome Atlas (TCGA) cohort using a machine learning algorithm. After obtaining a risk model from the training cohort, we further validated the model for predicting the prognosis in the test cohort, the entire dataset and two external GEO datasets. Then we explored the roles of the risk model in predicting immune cell infiltration, immunotherapeutic responses and genomic mutations. The results revealed that this risk model held promise for predicting the prognostic outcomes and immunotherapeutic responses of GC patients. Our findings provide ideas for integrating multiple screening methods for risk modeling through machine learning algorithms.

Remodeling tumor microenvironment with natural products to overcome drug resistance

With cancer incidence rates continuing to increase and occurrence of resistance in drug treatment, there is a pressing demand to find safer and more effective anticancer strategy for cancer patients. Natural products, have the advantage of low toxicity and multiple action targets, are always used in the treatment of cancer prevention in early stage and cancer supplement in late stage. Tumor microenvironment is necessary for cancer cells to survive and progression, and immune activation is a vital means for the tumor microenvironment to eliminate cancer cells. A number of studies have found that various natural products could target and regulate immune cells such as T cells, macrophages, mast cells as well as inflammatory cytokines in the tumor microenvironment. Natural products tuning the tumor microenvironment via various mechanisms to activate the immune response have immeasurable potential for cancer immunotherapy. In this review, it highlights the research findings related to natural products regulating immune responses against cancer, especially reveals the possibility of utilizing natural products to remodel the tumor microenvironment to overcome drug resistance.

Mapping the adult human esophagus in vivo and in vitro

Many esophageal diseases can arise during development or throughout life. Therefore, well-characterized in vitro models and detailed methods are essential for studying human esophageal development, homeostasis and disease. Here, we (1) create an atlas of the cell types observed in the normal adult human esophagus; (2) establish an ancestrally diverse biobank of in vitro esophagus tissue to interrogate homeostasis and injury; and (3) benchmark in vitro models using the adult human esophagus atlas. We created a single-cell RNA sequencing reference atlas using fresh adult esophagus biopsies and a continuously expanding biobank of patient-derived in vitro cultures (n=55 lines). We identify and validate several transcriptionally distinct cell classes in the native human adult esophagus, with four populations belonging to the epithelial layer, including basal, epibasal, early differentiating and terminally differentiated luminal cells. Benchmarking in vitro esophagus cultures to the in vivo reference using single-cell RNA sequencing shows that the basal stem cells are robustly maintained in vitro, and the diversity of epithelial cell types in culture is dependent on cell density. We also demonstrate that cultures can be grown in 2D or as 3D organoids, and these methods can be employed for modeling the complete epithelial layers, thereby enabling in vitro modeling of the human adult esophagus.

Crosstalk between tumor-associated macrophages and tumor cells promotes chemoresistance via CXCL5/PI3K/AKT/mTOR pathway in gastric cancer

BACKGROUND

5-fluorouracil (5-FU)-based chemotherapy regimen has been widely used for the treatment of gastric cancer, but meanwhile the development of chemotherapeutic resistance remains a major clinical challenge. Tumor microenvironment (TME) frequently correlates with the development of chemoresistance in human cancer. As a major component of TME, the role of tumor-associated macrophages (TAMs) in the chemoresistance of gastric cancer has not been fully elucidated.

METHODS

Immunohistochemistry (IHC) was applied to detect the density of TAMs in clinical samples of 103 patients with gastric cancer who had undergone 5-FU-based neoadjuvant chemotherapy. 5-FU-resistant gastric cell lines MKN45-R and HGC27-R were established, macrophages were then separately co-cultured with MKN45-R, HGC27-R cells and their parental cells. The effect of gastric cancer cells on the polarization of macrophages, the biological function of M2-polaried macrophages and the mechanism for promoting 5-FU-resistance were investigated. Then the correlation between the expression of CXC motif chemokine ligand 5 (CXCL5) and the infiltration of hemoglobin scavenger receptor (CD163) positive and mannose receptor (CD206) positive macrophages was analyzed, the prognostic value of CXCL5 expression in clinical samples was further explored.

RESULTS

The high infiltration of macrophages marked by CD68 in gastric cancer samples was significantly associated with the resistance of gastric cancer to chemotherapy. Gastric cancer cells could modulate macrophages to M2-like polarization through indirect co-culture, and chemoresistant cells were more efficient in inducing macrophages polarization to M2 phenotype. Co-culturing M2-polarized macrophages in turn enhanced 5-FU-resistance of gastric cancer cells, and it was further verified that CXCL5 derived from M2-polarized macrophages promoted chemoresistance through activing the PI3K/AKT/mTOR pathway. Besides, high level of CXCL5 could recruit monocytes to form more M2-polarized macrophages. Clinically, high expression of CXCL5 in gastric cancer samples was associated with the high infiltration of CD163 positive macrophages and CD206 positive macrophages, and patients with high expression of CXCL5 presented lower overall survival (OS) rates than those with low expression of CXCL5.

CONCLUSION

Interaction between TAMs and gastric cancer cells promoted chemoresistance in gastric cancer via CXCL5/PI3K/AKT/mTOR pathway. Thus, targeting TAMs and blocking the cell-cell crosstalk between TAMs and gastric cancer cells may represent prospective therapeutic strategies for patients with gastric cancer.

Construction of a Cuprotosis-Related Gene-Based Model to Improve the Prognostic Evaluation of Patients with Gastric Cancer

Background

Gastric cancer (GC) is one of the most serious gastrointestinal malignancies with bad prognosis. The association between GC and cuprotosis-related genes has not been reported.

Methods

The clinical and RNA expression of patients with GC were downloaded from TCGA database. The CIBERSORT package was used to quantify the abundance of specific cell types. Using the Cox regression analysis, we conducted a prognostic nomogram model based on cuprotosis-related differential genes in GC. We evaluated the prognostic power of this model using the Kaplan-Meier (K-M) survival curve analysis, decision curve analysis (DCA), and receiver operating characteristic (ROC) curve analysis.

Results

The plasma cells, monocytes, and mast cells in GC tissue were significantly less than those in adjacent tissue (p < 0.05), while T cell CD4 memory activated macrophage M0, macrophage M1, and macrophages in GC tissue. The number of M2 was significantly more than that in the adjacent tissue (p < 0.05). Additionally, GC patients in the test group, the training group, and all the sample groups had shorter survival time with the increase of the risk factor (p < 0.05). The nomogram of GC based on cuprotosis prognosis-related genes was conducted. The AUC of the nomogram to predict 1-, 3-, and 5-year survival rate was 0.618, 0.618, and 0.625, respectively.

Conclusion

A novel cuprotosis-related gene signature impacts on the prognosis of GC. Our research provides new insights and potential targets for studying the link between GC and cuprotosis point, thereby providing new insights into understanding the molecular mechanism of GC.

Expression profiles of m6A RNA methylation regulators, PD-L1 and immune infiltrates in gastric cancer

Gastric cancer is the fourth most frequent cancer and has a high death rate. Immunotherapy represented by PD-1 has brought hope for the treatment of advanced gastric cancer. Methylation of the m6A genes is linked to the onset and progression of numerous cancers, but there are few studies on gastric cancer. The main purpose of this study aims to analyze the relationship between m6A RNA methylation regulators, PD-L1, prognosis and tumor immune microenvironment (TIME) in gastric cancer. The Cancer Genome Atlas (TCGA) and Genotype Tissue Expression (GTEx) databases were used to acquire transcriptomic data and clinical information from gastric cancer patients. The changes in m6A regulator expression levels in gastric cancer tissues and normal tissues were studied. Consensus clustering analysis was used to separate gastric cancer samples into two categories. We employed Least Absolute Shrinkage, Selection Operator (LASSO) Cox regression analysis, Gene Set Enrichment Analysis (GSEA), and cBioPortal to analyze the m6A regulators, PD-L1 and TIME in gastric cancer. In gastric cancer tissues, the majority of m6A regulatory factors are considerably overexpressed. Two gastric cancer subgroups (Cluster1/2) based on consensus clustering of 21 m6A regulators. PD-L1 and PD-1 expression levels were significantly higher in gastric cancer tissues, and they were significantly linked with METTL3, WTAP, HNRNPD, ZC3H7B, METTL14, FTO, PCIF1, HNRNPC, YTHDF1 and YTDHF2. Cluster1 showed a large increase in resting memory CD4⁺ T cells, regulatory T cells, naïve B cells, active NK cells, and resting Mast cells. Cluster1 and Cluster2 were shown to be involved in numerous critical signaling pathways, including base excision repair, cell cycle, nucleotide excision repair, RNA degradation, and spliceosome pathways. Gastric cancer RiskScores based on prognostic factors have been found as independent prognostic indicators. The amount of tumor-infiltrating immune cells is dynamically affected by changes in the copy number of m6A methylation regulators associated with TIME.

Characterization of Immune-Related Molecular Subtypes and a Prognostic Signature Correlating With the Response to Immunotherapy in Patients With Gastric Cancer

Gastric cancer (GC) is a disease characterized by high molecular and phenotypic heterogeneity and represents a leading cause of cancer-related death worldwide. The tumor immune microenvironment (TIME) affects the response to immunotherapy and the prognosis of patients with GC. Explorations of the TIME in GC and characterization of molecular subtypes might enhance personalized treatment and facilitate clinical decision-making. In this study, two molecular subtypes were defined through unsupervised consensus clustering based on immune-related dysregulated genes. Then, patients with different molecular subtypes of GC were shown to have distinct differences in sensitivity to immune checkpoint blockers (ICBs). The immune-related prognostic signature was established utilizing least absolute shrinkage and selection operator (LASSO)-Cox regression analysis. Three independent external cohorts and the IMvigor210 cohort were introduced to validate the robustness of IPRS. scRNA-seq data of GC samples were used to decipher the underlying mechanisms of how IPRS contributes to the TIME. GC biospecimens were collected for RT-qPCR to further validate our findings. In summary, we characterized the abnormal TIME of GC and constructed a reliable immune-related prognostic signature correlating with the response to immunotherapy. This study may provide new strategies for developing individualized treatments for patients with GC.

The immune microenvironment in gastric adenocarcinoma

Like most solid tumours, the microenvironment of epithelial-derived gastric adenocarcinoma (GAC) consists of a variety of stromal cell types, including fibroblasts, and neuronal, endothelial and immune cells. In this article, we review the role of the immune microenvironment in the progression of chronic inflammation to GAC, primarily the immune microenvironment driven by the gram-negative bacterial species Helicobacter pylori. The infection-driven nature of most GACs has renewed awareness of the immune microenvironment and its effect on tumour development and progression. About 75-90% of GACs are associated with prior H. pylori infection and 5-10% with Epstein-Barr virus infection. Although 50% of the world's population is infected with H. pylori, only 1-3% will progress to GAC, with progression the result of a combination of the H. pylori strain, host susceptibility and composition of the chronic inflammatory response. Other environmental risk factors include exposure to a high-salt diet and nitrates. Genetically, chromosome instability occurs in ~50% of GACs and 21% of GACs are microsatellite instability-high tumours. Here, we review the timeline and pathogenesis of the events triggered by H. pylori that can create an immunosuppressive microenvironment by modulating the host's innate and adaptive immune responses, and subsequently favour GAC development.

Ferroptosis and its Role in Gastric Cancer

Gastric cancer (GC) is the fifth most common cancer and the third leading cause of cancer-related deaths worldwide. Currently, surgery is the treatment of choice for GC. However, the associated expenses and post-surgical pain impose a huge burden on these patients. Furthermore, disease recurrence is also very common in GC patients, thus necessitating the discovery and development of other potential treatment options. A growing body of knowledge about ferroptosis in different cancer types provides a new perspective in cancer therapeutics. Ferroptosis is an iron-dependent form of cell death. It is characterized by intracellular lipid peroxide accumulation and redox imbalance. In this review, we summarized the current findings of ferroptosis regulation in GC. We also tackled on the action of different potential drugs and genes in inducing ferroptosis for treating GC and solving drug resistance. Furthermore, we also explored the relationship between ferroptosis and the tumor microenvironment in GC. Finally, we discussed areas for future studies on the role of ferroptosis in GC to accelerate the clinical utility of ferroptosis induction as a treatment strategy for GC.

Applications and Achievements of Single-Cell Sequencing in Gastrointestinal Cancer

Gastrointestinal cancer represents a public health concern that seriously endangers human health. The emerging single-cell sequencing (SCS) technologies are different from the large-scale sequencing technologies which provide inaccurate data. SCS is a powerful tool for deciphering the single-cell resolutions of cellular and molecular landscapes, revealing the features of single-cell genomes, transcriptomes, and epigenomes. Recently, SCS has been applied in the field of gastrointestinal cancer research for clarifying the origin and heterogeneity of gastrointestinal cancer, acquiring micro-environmental information, and improving diagnostic and treatment methods. This review outlines the applications of SCS in gastrointestinal cancer research and summarizes the most recent advances in the field.

Identification of AKIRIN2 as a potential biomarker and correlation with immunotherapy in gastric adenocarcinoma by integrated bioinformatics analysis

Gastric adenocarcinoma is major type of gastric cancer that endangers human health. AKIRIN2 has been shown to be associated with cholangiocarcinoma promoting invasion and angiogenesis. In this study, AKIRIN2 is highly expressed in Gastric adenocarcinoma through bioinformatics analysis based on Stomach adenocarcinoma samples data from The Cancer Genome Atlas. Correlation analysis showed that the high-expression of AKIRIN2 was associated with poor survival rate compared to the low-expression group. Univariate and multivariate Cox regression analyses determined the correlation between clinical characteristics and overall survival. Next, the correlation between AKIRIN2 and immune infiltration was evaluated. The distribution of 24 immune cells and their correlation with the expression of AKIRIN2 were explored using the immune cell database. In addition, three Immune cell methods were used to verify the positive correlation between immune cells and AKIRIN2. Also, Genomics of Drug Sensitivity in Cancer database was utilized to verify the correlation between AKIRIN2 expression level and the efficacy of chemotherapy and immunotherapy. The results showed that AKIRIN2 is an effective biomarker of Gastric adenocarcinoma prognosis, which can guide chemotherapy and immunotherapy and clarify the progress of Gastric adenocarcinoma promoted by immune microenvironment.

Prediction of Metabolic Profiles from Transcriptomics Data in Human Cancer Cell Lines

The Metabolome and Transcriptome are mutually communicating within cancer cells, and this interplay is translated into the existence of quantifiable correlation structures between gene expression and metabolite abundance levels. Studying these correlations could provide a novel venue of understanding cancer and the discovery of novel biomarkers and pharmacological strategies, as well as laying the foundation for the prediction of metabolite quantities by leveraging information from the more widespread transcriptomics data. In the current paper, we investigate the correlation between gene expression and metabolite levels in the Cancer Cell Line Encyclopedia dataset, building a direct correlation network between the two molecular ensembles. We show that a metabolite/transcript correlation network can be used to predict metabolite levels in different samples and datasets, such as the NCI-60 cancer cell line dataset, both on a sample-by-sample basis and in differential contrasts. We also show that metabolite levels can be predicted in principle on any sample and dataset for which transcriptomics data are available, such as the Cancer Genome Atlas (TCGA).

The ambiguous role of obesity in oncology by promoting cancer but boosting antitumor immunotherapy

Obesity is nowadays considered a pandemic which prevalence's has been steadily increasingly in western countries. It is a dynamic, complex, and multifactorial disease which propitiates the development of several metabolic and cardiovascular diseases, as well as cancer. Excessive adipose tissue has been causally related to cancer progression and is a preventable risk factor for overall and cancer-specific survival, associated with poor prognosis in cancer patients. The onset of obesity features a state of chronic low-grade inflammation and secretion of a diversity of adipocyte-derived molecules (adipokines, cytokines, hormones), responsible for altering the metabolic, inflammatory, and immune landscape. The crosstalk between adipocytes and tumor cells fuels the tumor microenvironment with pro-inflammatory factors, promoting tissue injury, mutagenesis, invasion, and metastasis. Although classically established as a risk factor for cancer and treatment toxicity, recent evidence suggests mild obesity is related to better outcomes, with obese cancer patients showing better responses to treatment when compared to lean cancer patients. This phenomenon is termed obesity paradox and has been reported in different types and stages of cancer. The mechanisms underlying this paradoxical relationship between obesity and cancer are still not fully described but point to systemic alterations in metabolic fitness and modulation of the tumor microenvironment by obesity-associated molecules. Obesity impacts the response to cancer treatments, such as chemotherapy and immunotherapy, and has been reported as having a positive association with immune checkpoint therapy. In this review, we discuss obesity's association to inflammation and cancer, also highlighting potential physiological and biological mechanisms underlying this association, hoping to clarify the existence and impact of obesity paradox in cancer development and treatment.

Immune Score Predicts Outcomes of Gastric Cancer Patients Treated with Adjuvant Chemoradiotherapy

Background

Substantial evidence has demonstrated that tumor-infiltrating lymphocytes (TILs) are correlated with patient prognosis. The TIL-based immune score (IS) affects prognosis in various cancers, but its prognostic impact in gastric cancer (GC) patients treated with adjuvant chemoradiotherapy remains unclear.

Methods

A total of 101 GC patients who received chemoradiotherapy after gastrectomy were retrospectively analyzed in this study. Immunohistochemistry staining for CD3+ and CD8+ T-cell counts in both tumor center (CT) and invasive margin (IM) regions was built into the IS. Patients were then divided into three groups based on their differential IS levels. The correlation between IS and clinical parameters was analyzed. The prognostic impact of IS and clinical parameters was evaluated using Kaplan-Meier analysis and Cox proportional hazard regression analysis. Receiver operating characteristic (ROC) curves were plotted to compare the area under the curve (AUC) of IS with other clinical parameters. Nomograms for disease-free survival (DFS) and overall survival (OS) prediction were constructed based on the identified parameters.

Results

Finally, 20 (19.8%), 57 (56.4%), and 24 (23.8%) GC patients were identified with low, intermediate, and high IS levels, respectively. GC patients with higher IS levels exhibited better DFS (p < 0.001) and OS (p < 0.001). IS was an independent prognostic factor for both DFS (p < 0.001) and OS (p < 0.001) in multivariate analysis. IS presented a better predictive ability than the traditional pathological tumor-node-metastasis (pTNM) staging system (AUC: 0.801 vs. 0.677 and 0.800 vs. 0.660, respectively) with respect to both DFS and OS. The C-index of the nomograms for DFS and OS prediction was 0.737 and 0.774, respectively.

Conclusions

IS is a strong predictive factor for both DFS and OS in GC patients treated with adjuvant chemoradiotherapy, which may complement the traditional pTNM staging system.

Helicobacter pylori and gastric cancer: a lysosomal protease perspective

The intimate involvement of pathogens with the heightened risk for developing certain cancers is an area of research that has captured a great deal of attention over the last 10 years. One firmly established paradigm that highlights this aspect of disease progression is in the instance of Helicobacter pylori infection and the contribution it makes in elevating the risk for developing gastric cancer. Whilst the molecular mechanisms that pinpoint the contribution that this microorganism inflicts towards host cells during gastric cancer initiation have come into greater focus, another picture that has also emerged is one that implicates the host's immune system, and the chronic inflammation that can arise therefrom, as being a central contributory factor in disease progression. Consequently, when taken with the underlying role that the extracellular matrix plays in the development of most cancers, and how this dynamic can be modulated by proteases expressed from the tumor or inflammatory cells, a complex and detailed relationship shared between the individual cellular components and their surroundings is coming into focus. In this review article, we draw attention to the emerging role played by the cathepsin proteases in modulating the stage-specific progression of Helicobacter pylori-initiated gastric cancer and the underlying immune response, while highlighting the therapeutic significance of this dynamic and how it may be amenable for novel intervention strategies within a basic research or clinical setting.

Diabetes mellitus contribution to the remodeling of the tumor microenvironment in gastric cancer

Compelling pieces of evidence derived from both clinical and experimental research has demonstrated the crucial contribution of diabetes mellitus (DM) as a risk factor associated with increased cancer incidence and mortality in many human neoplasms, including gastric cancer (GC). DM is considered a systemic inflammatory disease and therefore, this inflammatory status may have profound effects on the tumor microenvironment (TME), particularly by driving many molecular mechanisms to generate a more aggressive TME. DM is an active driver in the modification of the behavior of many cell components of the TME as well as altering the mechanical properties of the extracellular matrix (ECM), leading to an increased ECM stiffening. Additionally, DM can alter many cellular signaling mechanisms and thus favoring tumor growth, invasion, and metastatic potential, as well as key elements in regulating cellular functions and cross-talks, such as the microRNAs network, the production, and cargo of exosomes, the metabolism of cell stroma and resistance to hypoxia. In the present review, we intend to highlight the mechanistic contributions of DM to the remodeling of TME in GC.

Bioinformatics analysis identifying FBXO45 gene as a potential oncogene in esophageal cancer

BACKGROUND

F-box protein 45 (FBXO45) is a member of the F-box protein family, and is reportedly involved in the progression of many diseases. However, its role in esophageal cancer (ESCA) remains unclear.

METHODS

The expression, clinical characteristics, gene function, pathway, and correlation between the infiltration of different immune cells were analyzed using public data. The pan-cancer expression of FBXO45 was assessed using the TIMER2 database. The expression of FBXO45 in different tumor stages and histology subtypes were evaluated using the UALCAN database. The protein-protein interaction (PPI) network was constructed using the STRING database. Immune cell infiltration data were downloaded from the ImmuCellAI database.

RESULTS

The top 300 genes most positively correlated with FBXO45 were screened into the enrichment analysis. The functional enrichment results showed that FBXO45 was mainly associated with proteasomal protein catabolic process and the regulation of DNA metabolic processing in the biological process (BP) category; spindle, chromosomal region, and focal adhesion in the cellular component category; and ATPase activity and ubiquitin-protein transferase activity terms in the molecular function category. FBXO45 was overexpressed in ESCA and other cancer types. FBXO45 expression was positively associated with the infiltration levels of immunosuppressive cells, such as CD8+ (cluster of differentiation 8+) T cells and NK (natural killer cell) cells, in ESCA. MYCBP2 and SKP1 were most associated with FBXO45.

CONCLUSIONS

Our results suggested that FBXO45 is a potential oncogene in ESCA. Elevated FBXO45 expression indicates a relatively immunosuppressive microenvironment.

The Ferroptosis-Related Noncoding RNA Signature as a Novel Prognostic Biomarker in the Tumor Microenvironment, Immunotherapy, and Drug Screening of Gastric Adenocarcinoma

Background

Ferroptosis is a new type of cell death different from apoptosis, necrosis, autophagy, and pyroptosis. This study aimed to explore the relationship between ferroptosis-related noncoding RNA (ncRNA) and gastric adenocarcinoma with regard to immunity and prognosis.

Methods

Ferroptosis-related ncRNA expression profiles and clinical pathology and overall survival information were collected from The Cancer Genome Atlas (TCGA) and the Gene Expression Omnibus database. The ferroptosis-related ncRNA signature was identified by Cox regression analysis and the least absolute shrinkage and selection operator analysis. The survival analysis, receiver operating characteristic (ROC) analysis, and decision curve analysis were adopted to evaluate the prognostic prediction performance of the signature. The correlation between risk and multiple clinical characteristics was analyzed using the chi-square test. The Gene Ontology, Kyoto Encyclopedia of Genes and Genomes, and gene set enrichment analysis were used for mining functions and pathways. The CIBERSORT, ssGSEA, and ESTIMATE algorithms were used to assess immune infiltration and the tumor microenvironment. The response of immunotherapy was predicted using the Submap algorithm, and the Connectivity Map and the ridge regression model were used to screen and evaluate drugs.

Results

A carcinogenic risk signature was constructed using five ferroptosis-related ncRNAs. It showed an extraordinary ability to predict the prognoses of patients with gastric adenocarcinoma [area under the ROC curve (AUC) after 6 years = 0.689; GSE84426, AUC after 6 years = 0.747]. The lower ferroptosis potential level and lower tumor mutation burden were related to the poor prognoses of patients. The high-risk group had more immune cell recruitment, and the overall effect of the anti-immune checkpoint immunotherapy was not as good as that of the low-risk group. The high- and low-risk groups were enriched in tumor- and immune-related pathways, respectively. The screened antitumor drugs, such as genistein, guanabenz, and betulinic acid, improved the survival of the patients.

Conclusions

The ferroptosis-related ncRNA signature is a potential carcinogenic prognostic biomarker of gastric adenocarcinoma.

Overexpression of NREP Promotes Migration and Invasion in Gastric Cancer Through Facilitating Epithelial-Mesenchymal Transition

The identification of biomarkers and effective therapeutic targets for gastric cancer (GC), the most common cause of cancer-related deaths around the world, is currently a major focus area in research. Here, we examined the utility of Neuronal Regeneration Related Protein (NREP) as a prognostic biomarker and therapeutic target for GC. We assessed the clinical relevance, function, and molecular role of NREP in GC using bioinformatics analysis and experimental validation. Our results showed that in GC, NREP overexpression was significantly associated with a poor prognosis. Our findings also suggested that NREP may be involved in the activation of cancer-associated fibroblasts and the epithelial-mesenchymal transition (EMT), with transforming growth factor β1 mediating both processes. In addition, NREP expression showed a positive correlation with the abundance of M2 macrophages, which are potent immunosuppressors. Together, these results indicate that NREP is overexpressed in GC and affects GC prognosis. Thus, NREP could be a prognostic biomarker and therapeutic target for GC.

Calmodulin 2 Facilitates Angiogenesis and Metastasis of Gastric Cancer via STAT3/HIF-1A/VEGF-A Mediated Macrophage Polarization

Background

Tumor-associated macrophages (TAMs) are indispensable to mediating the connections between cells in the tumor microenvironment. In this study, we intended to research the function and mechanism of Calmodulin2 (CALM2) in gastric cancer (GC)-TAM microenvironment.

Materials and methods

CALM2 expression in GC tissues and GC cells was determined through quantitative real-time PCR (qRT-PCR) and immunohistochemistry (IHC). The correlation between CALM2 level and the survival rate of GC patients was assessed. The CALM2 overexpression or knockdown model was constructed to evaluate its role in GC cell proliferation, migration, and invasion. THP1 cells or HUVECs were co-cultured with the conditioned medium of GC cells. Tubule formation experiment was done to examine the angiogenesis of endothelial cells. The proliferation, migration, and polarization of THP1 cells were measured. A xenograft model was set up in BALB/c male nude mice to study CALM2x’s effects on tumor growth and lung metastasis in vivo. Western Blot (WB) checked the profile of JAK2/STAT3/HIF-1/VEGFA in GC tissues and cells.

Results

In GC tissues and cell lines, CALM2 expression was elevated and positively relevant to the poor prognosis of GC patients. In in-vitro experiments, CALM2 overexpression or knockdown could facilitate or curb the proliferation, migration, invasion, and angiogenesis of HUVECs and M2 polarization of THP1 cells. In in-vivo experiments, CALM2 boosted tumor growth and lung metastasis. Mechanically, CALM2 could arouse the JAK2/STAT3/HIF-1/VEGFA signaling. It was also discovered that JAK2 and HIF-1A inhibition could attenuate the promoting effects of CALM2 on GC, HUVECs cells, and macrophages.

Conclusion

CALM2 modulates the JAK2/STAT3/HIF-1/VEGFA axis and bolsters macrophage polarization, thus facilitating GC metastasis and angiogenesis.

Exosome-derived noncoding RNAs in gastric cancer: functions and clinical applications

Exosomes are a subpopulation of the tumour microenvironment (TME) that transmit various biological molecules to promote intercellular communication. Exosomes are derived from nearly all types of cells and exist in all body fluids. Noncoding RNAs (ncRNAs) are among the most abundant contents in exosomes, and some ncRNAs with biological functions are specifically packaged into exosomes. Recent studies have revealed that exosome-derived ncRNAs play crucial roles in the tumorigenesis, progression and drug resistance of gastric cancer (GC). In addition, regulating the expression levels of exosomal ncRNAs can promote or suppress GC progression. Moreover, the membrane structures of exosomes protect ncRNAs from degradation by enzymes and other chemical substances, significantly increasing the stability of exosomal ncRNAs. Specific hallmarks within exosomes that can be used for exosome identification, and specific contents can be used to determine their origin. Therefore, exosomal ncRNAs are suitable for use as diagnostic and prognostic biomarkers or therapeutic targets. Regulating the biogenesis of exosomes and the expression levels of exosomal ncRNAs may represent a new way to block or eradicate GC. In this review, we summarized the origins and characteristics of exosomes and analysed the association between exosomal ncRNAs and GC development.

An Investigation of the Antigastric Cancer Effect in Tumor Microenvironment of Radix Rhei Et Rhizome: A Network Pharmacology Study

Background

Tumor microenvironment (TME) takes a vital effect on the occurrence and development of cancer. Radix Rhei Et Rhizome (RRER, Da-Huang in pinyin), a classical Chinese herb, has been widely used in gastric cancer (GC) for many years in China. However, inadequate systematic studies have focused on the anti-GC effect of RRER in TME. This study intended to uncover the mechanism of it by network pharmacology.

Methods

We collected compounds and targets of RRER from traditional Chinese medicine system pharmacology database and analysis platform (TCMSP) and SwissTargetPrediction. GC targets were obtained from GeneCards. Protein-protein interaction (PPI) network and RRER-GC-target network were built by STRING and Cytoscape 3.2.1. Furthermore, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis were performed using Database for Annotation, Visualization, and Integrated Discovery (DAVID).

Results

We obtained 92 compounds of RRER. A total of 10 key compounds and 20 key targets were selected by “RRER-GC-target network” topological analysis. GO analysis showed that the biological process mainly involved in response to the tumor necrosis factor, positive regulation of fibroblast proliferation, and DNA damage response, signal transduction by p53 class mediator resulting in cell cycle arrest. Molecular functions included cyclin-dependent protein serine/threonine kinase activity, RNA polymerase II transcription factor activity, ligand-activated sequence-specific DNA binding, and transmembrane receptor protein tyrosine kinase activity. Cellular components mainly were centrosome, cell surface, and membrane. KEGG pathway enrichment results mainly involved in the p53 signaling pathway, estrogen signaling pathway, and regulation of lipolysis in adipocytes.

Conclusion

This study explored the anti-GC mechanism of RRER from the perspective of TME based on network pharmacology, which contributed to the development and application of RRER.

A CT-based Radiomics Model for Prediction of Lymph Node Metastasis in Early Stage Gastric Cancer

RATIONALE AND OBJECTIVES

To develop and validate a CT-based radiomics model for preoperative prediction of lymph node metastasis (LNM) in early stage gastric cancer (EGC).

MATERIALS AND METHODS

Four hundred and sixty-three consecutive EGC patients were enrolled in this retrospective study. Radiomics features were extracted from portal venous phase CT scans. A radiomics signature was built based on highly reproducible features using the least absolute shrinkage and selection operator method. The predictive performance of radiomics signature was tested in the training and testing cohorts. Multivariate logistic regression analysis was conducted to build a radiomics-based model combined radiomics signature and lymph node status according to CT. Performance of the model was determined by its discrimination, calibration, and clinical usefulness.

RESULTS

The radiomics signature comprised six robust features showed significant association with LNM in both cohorts. A radiomics model that incorporated radiomics signature and CT-reported lymph node status showed good calibration and discrimination in the training cohort (AUC = 0.91) and testing cohort (AUC = 0.89). Decision curve analysis confirmed the clinical utility of this model.

CONCLUSION

The CT-based radiomics model showed favorable accuracy for prediction of LNM in EGC and may help to improve clinical decision-making.

CFP is a prognostic biomarker and correlated with immune infiltrates in Gastric Cancer and Lung Cancer

Complement factor properdin (CFP), encodes plasma glycoprotein, is a critical gene that regulates the complement pathway of the innate immune system. However, correlations of CFP in cancers remain unclear. In this study, the expression pattern and prognostic value of CFP in pan-cancer were analyzed via the Oncomine, PrognoScan, GEPIA and Kaplan-Meier plotters. In addition, we used immunohistochemical staining to validate CFP expression in clinical tissue samples. Finally, we evaluated the correlations between CFP and cancer immune infiltrates particularly in stomach adenocarcinoma (STAD) and lung adenocarcinoma (LUAD) by using GEPIA and TIMER databases. The results of database analysis and immunohistochemistry showed that the expression level of CFP in STAD and LUAD was lower than that in normal tissues. Low expression level of CFP was associated with poorer overall survival (OS), first progression (FP), post progression survival (PPS) and was detrimental to the prognosis of STAD and LUAD, specifically in stage 3, stage T3, stage N2 and N3 of STAD (P<0.05). Moreover, expression of CFP had significant positive correlations with the infiltration levels of CD8+ T cells, CD4+ T cells, macrophages, neutrophils and dendritic cells (DCs) in STAD and LUAD. Furthermore, gene markers of infiltrating immune cells exhibited different CFP-related immune infiltration patterns such as tumor-associated-macrophages (TAMs). These results suggest that CFP can serve as a prognostic biomarker for determining prognosis and immune infiltration in STAD and LUAD.

Tumor-Associated Macrophages and Inflammatory Microenvironment in Gastric Cancer: Novel Translational Implications

Gastric cancer (GC) represents the fifth most frequently diagnosed cancer worldwide, with a poor prognosis in patients with advanced disease despite many improvements in systemic treatments in the last decade. In fact, GC has shown resistance to several treatment options, and thus, notable efforts have been focused on the research and identification of novel therapeutic targets in this setting. The tumor microenvironment (TME) has emerged as a potential therapeutic target in several malignancies including GC, due to its pivotal role in cancer progression and drug resistance. Therefore, several agents and therapeutic strategies targeting the TME are currently under assessment in both preclinical and clinical studies. The present study provides an overview of available evidence of the inflammatory TME in GC, highlighting different types of tumor-associated cells and implications for future therapeutic strategies.

Immune Cell Landscape in Gastric Cancer

Background

The tumor-infiltrating immune cells are closely associated with the prognosis of gastric cancer (GC). This article is aimed at determining the composition change of immune cells and immune regulatory factors in GC and normal tissues, depicting their prognosis value in GC, and revealing the relationship between them and GC clinical parameters.

Methods

We used CIBERSORT to calculate the proportion of 22 immune cells in the GC or normal tissues; a t-test was applied to assess the expression difference of immune cells and immune regulatory factors in normal and GC tissues. The relationship of the immune cells, immune regulatory factors, and GC patients' clinical characteristics was assessed by univariate analysis.

Results

In this study, we found that the proportion of macrophages increased, while plasma cells and monocytes decreased in GC tissues. In these immune fractions, Tregs and naïve B cells were found to be correlated with GC patients' prognosis. Interestingly, the expression of immune regulatory factors was ambiguous with their classical function in GC tissues. For example, TIM-3, FOXP3, and CMTM6 were overexpressed, while CD27 and PD-1 were underexpressed in GC tissues. We also found that IDO1, PD-1, TIGIT, and TIM-3 were highly expressed in high-grade GC tissues, the HERC2 expression level was related to patients' gender, and the TIGIT expression level was sensitive to targeted therapy. Furthermore, our results suggested that the infiltration of Tregs and naive B cells was strongly correlated with the T stage, radiation therapy, targeted molecular therapy, and the expression levels of TIM-3 and FOXP3 in GC.

Conclusion

The expression pattern of tumor-infiltrating immune cells and immune regulatory factors was systematically depicted in the GC tumor microenvironment, indicating that individualized treatment based on the tumor-infiltrating immune cells and immune regulatory factors may be beneficial to GC patients.

MUC4 is a novel mediator in H. pylori infection-related pancreatic cancer

Pancreatic cancer (PC) is a common malignant disease worldwide. Among the potential pathogenic factors, Helicobacter pylori (H. pylori) infection has been associated with the tumorigenesis of PC. The present study aimed to identify the differentially expressed genes (DEGs) of H. pylori infection-associated PC and to investigate the key factors involved in PC tumorigenesis. Using bioinformatics methods, overlapping DEGs and key gene were identified from H. pylori-infected gastric mucosa (GM) and H. pylori infection-associated PC. Survival and tumor stage analyses were performed to assess the clinical associations. In addition, mucin 4 (MUC4) mRNA expression levels were measured in patient blood and tumor samples. According to the correlation analyses of four genes co-expressed, potential biological processes were identified. MUC4 was identified to be associated with H. pylori infection, and its levels were significantly upregulated in PC samples compared with those in normal samples in TCGA dataset, the PC cell line and patient tissue samples. H. pylori infection was also associated with MUC4 expression in patients' blood and tissue samples. In conclusion, the results of the present study revealed a potentially pathogenic role of MUC4 in H. pylori infection-associated PC. Thus, the tumorigenesis and metastasis of PC may be prevented by treating the H. pylori infection or using MUC4 antagonists.

Biomarkers for Precision Treatment in Gastric Cancer

BACKGROUND

Gastric cancer (GC) is one of the most lethal cancers worldwide. Although GC was historically considered a single entity within the organ of origin, nowadays it is acknowledged that GC represents a heterogeneous disease. Nevertheless, in this field there is still a lack of biomarkers able to guide the choice of the best treatment options for each patient. This review aims to summarize the prognostic and predictive biomarkers evaluated in GC and their role as a guide for treatment for precision medicine.

SUMMARY

Human epidermal growth factor receptor 2 overexpression represents the only predictive molecular biomarker validated in GC, while its prognostic role is still controversial. Microsatellite instability and Epstein-Barr virus status are promising for prediction of the response to immunotherapy. The role of other biomarkers (ctDNA, programmed death ligand 1 [PD-L1], and TMB), as well as the practical application of molecular classifications, requires further evaluation before use in clinical practice. 18-FDG-PET scan could be useful as a predictive tool in non-metastatic GC patients receiving a perioperative approach. Finally, the tumor microenvironment may have an evolving role in the future.

KEY MESSAGES

GC is a heterogeneous disease and targeted approaches are needed. The finding of prognostic and predictive factors is a hot topic in the field of GC personalized medicine.

Esophageal Microenvironment: From Precursor Microenvironment to Premetastatic Niche

Esophageal cancer (EC) is the sixth most deadly cancer, and its incidence is still increasing year by year. Although the researches on the molecular mechanisms of EC have been widely carried out and incremental progress has been made, its overall survival rate is still low. There is cumulative evidence showing that the esophageal microenvironment plays a vital role in the development of EC. In precancerous lesions of the esophagus, high-risk environmental factors can promote the development of precancerous lesions by inducing the production of inflammatory factors and the recruitment of immune cells. In the tumor microenvironment, tumor-promoting cells can inhibit anti-tumor immunity and promote tumor progression through a variety of pathways, such as bone marrow-derived suppressor cells (MDSCs), tumor-associated fibroblasts (CAFs), and regulatory T cells (Tregs). The formation of extracellular hypoxia and acidic microenvironment and the change of extracellular matrix stiffness are also important factors affecting tumor progression and metastasis. Simultaneously, primary tumor-derived cytokines and bone marrow-derived immune cells can also promote the formation of pre-metastasis niche of EC lymph nodes, which are beneficial to EC lymph node metastasis. Further research on the specific mechanism of these processes in the occurrence, development, and metastasis of each EC subtype will support us to grasp the overall pre-cancerous prevention, targeted treatment, and metastatic assessment of EC.