Inflammatory microenvironment contributes to epithelial-mesenchymal transition in gastric cancer

Poorly cohesive gastric cancer with increased epithelial‑mesenchymal transition is associated with a poor prognosis

The present study examined the surgical outcome and prognosis of patients with poorly cohesive carcinoma (PCC), and characterized the molecular pathological factors, epithelial-mesenchymal transition (EMT) and interstitial signals of the disease. A total of 281 patients who underwent gastric cancer (GC) surgery between April 2015 and August 2020 were included. Furthermore, tissue samples from another 197 patients with GC who underwent surgery between 1999 and 2003 were assessed using a tissue microarray. Preoperatively treated cases and endoscopic submucosal dissection cases were excluded, and multiple blocks containing the invasion region were collected for tissue microarray. For tissue microarray analysis, the clinicopathological factors of protein wnt3a (wnt3a), leucine-rich repeat-containing G-protein coupled receptor 5, transforming growth factor-β-induced, phosphorylated serine/threonine-protein kinase mTOR and E-cadherin expression were collected as EMT markers. The results of the surgical case evaluation and tissue microarray indicated that PCC was more common in younger patients and women, as the ratio of women to men was higher in the PCC group compared with that in the non-PCC group. However, none of the results revealed that the prognosis was worse in all patients with PCC compared with the non-PCC group. Furthermore, in the tissue microarray study, PCC samples exhibited significantly decreased expression of the cell adhesion molecule E-cadherin, suggesting enhanced EMT, which activates wnt3a signaling. PCC with increased EMT was significantly associated with a poor prognosis.

Collagen synthase P4HA3 as a novel biomarker for colorectal cancer correlates with prognosis and immune infiltration

Objective

In this study, we aimed to determine whether proly4-hydroxylase-III (P4HA3) could be used as a biomarker for the diagnosis of colorectal cancer (CRC) as well as for determining prognosis.

Methods

We used The Cancer Genome Atlas (TCGA) database to analyze P4HA3 expression in CRC and further investigated the association between P4HA3 and clinicopathological parameters, immune infiltration, and prognosis of patients with CRC. Enrichment analysis was conducted to investigate the potential biological role of P4HA3 in CRC. To verify the results of TCGA analysis, we performed immunohistochemical staining of 180 clinical CRC tissue samples to probe into the relationship of P4HA3 expression with lymphocyte infiltration and immune checkpoints expression.

Results

The expression of P4HA3 was significantly higher in CRC tissues and associated with a higher degree of malignancy and poorer prognosis in CRC. The results of enrichment analysis indicated that P4HA3 may be associated with the epithelial-mesenchymal transition process and the immune response. Immunohistochemical staining results showed that high P4HA3 expression was associated with high infiltration levels of CD8+ and Foxp3+ TILs and high PD-1/PD- L1 expression. Lastly, patients with CRC co-expressing P4HA3 and PD-1 had a significantly worse prognosis.

Conclusion

High expression of P4HA3 is associated with adverse clinical features and immune cell infiltration in CRC, and has the potential to serve as a biomarker for predicting CRC prognosis.

Integrative analysis revealed a correlation of PIAS family genes expression with prognosis, immunomodulation and chemotherapy

BACKGROUND

Protein inhibitor of activated STATs (PIAS) has pleiotropic biological effects, such as protein post-translational modification, transcriptional coregulation and gene editing. It is reported that PIAS family genes are also correlated with immune cells infiltration in cancers that highlights their unnoticed biological role in tumor progression. However, the relationship of their expression with prognosis, immune cell infiltration, tumor microenvironment, and immunotherapy in pan-cancer has been rarely reported.

METHODS

The multi-omics data were used to investigate the expression level of PIAS family members in pan-cancer, and the prognostic value of their expression in different tumors was analyzed by univariate Cox regression and Kaplan-Meier. Correlation analysis was used to investigate the relationship of PIAS gene expression with tumor microenvironment, immune infiltrating subtypes, stemness score and drug sensitivity. In addition, we also used wound healing and transwell assays to verify the biological effects of PIAS family gene expression on invasion and metastasis of HCC cells.

RESULTS

We found that PIAS family genes expression is significantly heterogeneous in tumors by multi-genomic analysis, and associated with poor prognosis in patients with multiple types of cancer. Furthermore, we also found that genetic alterations of PIAS family genes were not only common in different types of human tumors, but were also significantly associated with disease-free survival (DFS) across pan-cancer. Single-cell analysis revealed that PIAS family genes were mainly distributed in monocytes/macrophages. Additionally, we also found that their expression was associated with tumor microenvironment (including stromal cells and immune cells) and stemness score (DNAss and RNAss). Drug sensitivity analysis showed that PIAS family genes were able to predict the response to chemotherapy and immunotherapy. PIAS family genes expression is closely related to tumor metastasis, especially PIAS3. High PIAS3 expression significantly promotes the migration and invasion of liver cancer cell lines (HCC-LM3 and MHCC97-H).

CONCLUSIONS

Taking together, these findings contribute to determine whether the PIAS family genes are a potential oncogenic target gene, which have important contribution for the development of cancer immunotherapy.

Integrated analysis of single-cell and bulk RNA-sequencing data reveals the prognostic value and molecular function of THSD7A in gastric cancer

The biological role and prognostic value of thrombospondin domain-containing 7A (THSD7A) in gastric cancer remain unclear. Our purpose was to determine the molecular mechanisms underlying the functioning of THSD7A and its prognostic value in gastric cancer. Gastric cancer-associated single cell and bulk RNA sequencing data obtained from two databases, were analyzed. We used bulk RNA sequencing to examine the differential expression of THSD7A in gastric cancer and normal gastric tissues and explored the relationship between THSD7A expression and clinicopathological characteristics. Kaplan-Meier survival and Cox analyses revealed the prognostic value of THSD7A. Gene set enrichment and immune infiltration analyses were used to determine the cancer-promoting mechanisms of THSD7A and its effect on the immune microenvironment. We explored the relationship between THSD7A expression and sensitivity of anti-tumor drugs and immune checkpoint levels. Biological functions of THSD7A were validated at single-cell and in vitro levels. THSD7A expression was significantly increased in gastric cancer samples. High THSD7A expression was associated with poor clinical phenotypes and prognoses. Cox analysis showed that THSD7A was an independent risk factor for patients with gastric cancer. Enrichment analysis suggested that epithelial-mesenchymal transition and inflammatory responses may be potential pro-cancer mechanisms of THSD7A. Upregulation of THSD7A promoted infiltration by M2 macrophages and regulatory T cells. High THSD7A expression suppressed the sensitivity of patients with gastric cancer to drugs, such as 5-fluorouracil, bleomycin, and cisplatin, and upregulated immune checkpoints, such as HAVCR2, PDCD1LG2, TIGIT, and CTLA4. At the single cell level, THSD7A was an endothelial cell-associated gene and endothelial cells overexpressing THSD7A showed unique pro-oncogenic effects. In vitro experiments confirmed that THSD7A was overexpressed in gastric cancer samples and cells, and that knocking out THSD7A significantly inhibited gastric cancer cell proliferation and invasion. THSD7A overexpression may be a unique prognostic marker and therapeutic target in gastric cancer. Therefore, our study provides a new perspective on the precise treatment of gastric cancer.

Unveiling the immunomodulatory shift: Epithelial-mesenchymal transition Alters immune mechanisms of amniotic epithelial cells

Epithelial-mesenchymal transition (EMT) changes cell phenotype by affecting immune properties of amniotic epithelial cells (AECs). The present study shows how the response to lipopolysaccharide of cells collected pre- (eAECs) and post-EMT (mAECs) induces changes in their transcriptomics profile. In fact, eAECs mainly upregulate genes involved in antigen-presenting response, whereas mAECs over-express soluble inflammatory mediator transcripts. Consistently, network analysis identifies CIITA and Nrf2 as main drivers of eAECs and mAECs immune response, respectively. As a consequence, the depletion of CIITA and Nrf2 impairs the ability of eAECs and mAECs to inhibit lymphocyte proliferation or macrophage-dependent IL-6 release, thus confirming their involvement in regulating immune response. Deciphering the mechanisms controlling the immune function of AECs pre- and post-EMT represents a step forward in understanding key physiological events wherein these cells are involved (pregnancy and labor). Moreover, controlling the immunomodulatory properties of eAECs and mAECs may be essential in developing potential strategies for regenerative medicine applications.

Automated Assessment of the Area of Infiltration by CD8+ Cells in Gastric Carcinoma and Areas of Normal Mucosa as a Significant Prognostic Factor

In 139 patients with verified gastric cancer, the infiltration of the postoperative material with CD8+ cells was analyzed. Automated morphometric analysis of immunostained slides was performed separately in different specimen sites (tumor center, invasive edge, and peritumoral mucosa). The mean area of infiltrating CD8+ cells in the tumor center and in the invasive edge was not predictive, while in the peritumoral mucosa it provided a new negative predictive factor (hazard ratio 2.10; confidence interval 0.87-4.92, Cox regression) reliably associated with the TNM stage (hazard ratio 1.91; confidence interval 0.91-4.61, Cox regression).

Cancer-associated fibroblasts refine the classifications of gastric cancer with distinct prognosis and tumor microenvironment characteristics

Background

Cancer-associated fibroblasts (CAFs) are essential tumoral components of gastric cancer (GC), contributing to the development, therapeutic resistance and immune-suppressive tumor microenvironment (TME) of GC. This study aimed to explore the factors related to matrix CAFs and establish a CAF model to evaluate the prognosis and therapeutic effect of GC.

Methods

Sample information from the multiply public databases were retrieved. Weighted gene co-expression network analysis was used to identify CAF-related genes. EPIC algorithm was used to construct and verify the model. Machine-learning methods characterized CAF risk. Gene set enrichment analysis was employed to elucidate the underlying mechanism of CAF in the development of GC.

Results

A three-gene (GLT8D2, SPARC and VCAN) prognostic CAF model was established, and patients were markedly divided according to the riskscore of CAF model. The high-risk CAF clusters had significantly worse prognoses and less significant responses to immunotherapy than the low-risk group. Additionally, the CAF risk score was positively associated with CAF infiltration in GC. Moreover, the expression of the three model biomarkers were significantly associated with the CAF infiltration. GSEA revealed significant enrichment of cell adhesion molecules, extracellular matrix receptors and focal adhesions in patients at a high risk of CAF.

Conclusion

The CAF signature refines the classifications of GC with distinct prognosis and clinicopathological indicators. The three-gene model could effectively aid in determining the prognosis, drug resistance and immunotherapy efficacy of GC. Thus, this model has promising clinical significance for guiding precise GC anti-CAF therapy combined with immunotherapy.

The Role of EMT-Related lncRNAs in Ovarian Cancer

Ovarian cancer (OC) is one of the deadliest cancers worldwide; late diagnosis and drug resistance are two major factors often responsible for high morbidity and treatment failure. Epithelial-to-mesenchymal transition (EMT) is a dynamic process that has been closely linked with cancer. Long non-coding RNAs (lncRNAs) have been also associated with several cancer-related mechanisms, including EMT. We conducted a literature search in the PubMed database in order to sum up and discuss the role of lncRNAs in regulating OC-related EMT and their underlying mechanisms. Seventy (70) original research articles were identified, as of 23 April 2023. Our review concluded that the dysregulation of lncRNAs is highly associated with EMT-mediated OC progression. A comprehensive understanding of lncRNAs' mechanisms in OC will help in identifying novel and sensitive biomarkers and therapeutic targets for this malignancy.

The Roles of Innate Lymphoid Cells in the Gastric Mucosal Immunology and Oncogenesis of Gastric Cancer

Innate lymphoid cells (ILCs) are a group of innate immune cells that have garnered considerable attention due to their critical roles in regulating immunity and tissue homeostasis. They are particularly abundant in the gastrointestinal tract, where they have been shown to interact with commensal bacteria, pathogens, and other components of the local microenvironment to influence host immune responses to infection and oncogenesis. Their tissue-residency properties enable gastric ILCs a localized and rapid response to alert and stress, which indicates their key potential in regulating immunosurveillance. In this review, we discuss the current understanding of the role of ILCs in the gastric mucosa, with a focus on their interactions with the gastric microbiota and Helicobacter pylori and their contributions to tissue homeostasis and inflammation. We also highlight recent findings on the involvement of ILCs in the pathogenesis of gastric cancer and the implications of targeting ILCs as a therapeutic approach. Overall, this review provides an overview of the diverse functions of ILCs in gastric mucosa and highlights their potential as targets for future therapies for gastric cancer.

Prevention of malignant digestive system tumors should focus on the control of chronic inflammation

Chronic inflammation, through a variety of mechanisms, plays a key role in the occurrence and development of digestive system malignant tumors (DSMTs). In this study, we feature and provide a comprehensive understanding of DSMT prevention strategies based on preventing or controlling chronic inflammation. The development and evaluation of cancer prevention strategies is a longstanding process. Cancer prevention, especially in the early stage of life, should be emphasized throughout the whole life course. Issues such as the time interval for colon cancer screening, the development of direct-acting antiviral drugs for liver cancer, and the Helicobacter pylori vaccine all need to be explored in long-term, large-scale experiments in the future.

Cytokine-Like Protein 1 (CYTL1) as a Key Target of M-Stage Immune Infiltration in Stomach Adenocarcinoma

Background

Stomach adenocarcinoma (STAD) has an extremely high fatality rate worldwide, and survival after metastasis is extremely poor. Cytokine-like protein 1 (CYTL1) has prognostic significance in various tumors. We aimed to explore the impact and underlying molecular mechanisms of CYTL1 in STAD through bioinformatics analysis.

Methods

We used R software to analyze CYTL1 expression in STAD samples (n = 375) and normal samples (n = 32) in The Cancer Genome Atlas database. Kaplan-Meier analysis was used to verify the relationship between CYTL1 expression and overall survival (OS) and disease-specific survival (DSS) based on the clinical characteristics and subgroups of patients with STAD. Furthermore, univariate and multivariate Cox regression analyses were used to verify the outcome variables of OS and DSS in patients with STAD. Receiver operating characteristic curves were used to test the predictive power of CYTL1. The biological functions and signaling pathways of CYTL1 were determined using gene set enrichment analysis (GSEA), and the immune infiltration patterns of CYTL1 and correlation of immune-related markers were analyzed using single-sample GSEA (ssGSEA) and an estimate algorithm.

Results

In our research, low CYTL1 expression (tumor vs. normal) was noted in patients with STAD. High CYTL1 expression was detrimental to OS and DSS and had good diagnostic performance (AUC = 0.731). In the subtype analysis of STAD, T3 and T4 stages, N0 and N1 stages, M0 stage, gender (female), and age (≤65 years) showed different performances between OS and DSS. Univariate and multivariate Cox analyses identified CYTL1 as an independent factor, and logistic regression analysis indicated that CYTL1 was associated with M stage (OR = 3.406) and sex (OR = 1.535). GSEA of the differential genes of CYTL1 showed the possible involvement of immunity. ssGSEA and estimation algorithms were used to further evaluate whether immune cells were closely related to CYTL1 expression, and many markers of immune cells also had statistical significance with the expression of CYTL1.

Conclusion

CYTL1 may, thus, act as an independent prognostic factor for STAD and regulate STAD progression by affecting the immune microenvironment.

Manpixiao Decoction Halted the Malignant Transformation of Precancerous Lesions of Gastric Cancer: From Network Prediction to In-Vivo Verification

Manpixiao decoction (MPX), a traditional Chinese medicine formula, is mainly used to improve the gastric mucosal pathology and stomach discomfort in patients with gastric precancerous lesions. Precancerous lesion of gastric cancer (PLGC) refers to intestinal metaplasia and/or dysplasia based on gastric mucosal atrophy. Effective prevention and treatment of PLGC is of great significance to reduce the incidence of gastric cancer. Because of the complexity of the etiology and pathogenesis of PLGC, there is no unified and effective treatment plan in western medicine. In recent years, traditional Chinese medicine has shown obvious advantages in the treatment of PLGC and the prevention of its further progression to gastric cancer, relying on its multi-approach and multi-target comprehensive intervention characteristics. This study is designed to examine the protective effect of MPX against PLGC and further to reveal the engaged mechanism via integrating network pharmacology and in vivo experimental evidence. Network pharmacology results demonstrated that inflammation, immune responses, and angiogenesis might be associated with the efficacy of MPX in the treatment of PLGC, in which the PI3K-Akt, cellular senescence, P53 and protein processing in endoplasmic reticulum were involved. Then, we established a rat model of PLGC using a combination of N-methyl-N′-nitro-N-nitrosoguanidine (MNNG), sodium salicylate, irregular fasting, and ranitidine, and observed the effects after MPX treatment. Our result showed that MPX improved the pathological condition of gastric mucosa in PLGC rats and reduced the incidence of gastric cancer. Next, the analysis of serum inflammatory cytokines showed that MPX reduced the inflammation-related cytokines (such as IL-1α, IL-7, CSF-1, and CSF-3) in the serum. Additionally, MPX also had a regulation effect on the “protein/protein phosphorylation-signaling pathway” network in the core region of the PLGC rats. It is showed that MPX can inhibit the phosphorylation of PI3K-AKT, and downregulates the EGFR, β-catenin, and N-cadherin protein levels. These results indicate that MPX halted the PLGC progression through inhibiting EGFR-PI3K-AKT related epithelial-mesenchymal transition process.

The Role of Tumor Microenvironment and Immune Response in Colorectal Cancer Development and Prognosis

Colorectal cancer (CRC) is one of the most common cancers worldwide. The patient’s prognosis largely depends on the tumor stage at diagnosis. The pathological TNM Classification of Malignant Tumors (pTNM) staging of surgically resected cancers represents the main prognostic factor and guidance for decision-making in CRC patients. However, this approach alone is insufficient as a prognostic predictor because clinical outcomes in patients at the same histological tumor stage can still differ. Recently, significant progress in the treatment of CRC has been made due to improvements in both chemotherapy and surgical management. Immunotherapy-based approaches are one of the most rapidly developing areas of tumor therapy. This review summarizes the current knowledge about the tumor microenvironment (TME), immune response and its interactions with CRC development, immunotherapy and prognosis.

Epithelial-Mesenchymal Plasticity Induced by Discontinuous Exposure to TGFβ1 Promotes Tumour Growth

Simple Summary

In this manuscript, we used a non-genetically manipulated EMT/MET cell line model to demonstrate that epithelial mesenchymal plasticity occurring in normal cells generates co-existing phenotypically and functionally divergent cell subpopulations which result in fast growing tumours in vivo.

Abstract

Transitions between epithelial and mesenchymal cellular states (EMT/MET) contribute to cancer progression. We hypothesize that EMT followed by MET promotes cell population heterogeneity, favouring tumour growth. We developed an EMT model by on and off exposure of epithelial EpH4 cells (E-cells) to TGFβ1 that mimics phenotypic EMT (M-cells) and MET. We aimed at understanding whether phenotypic MET is accompanied by molecular and functional reversion back to epithelia by using RNA sequencing, immunofluorescence (IF), proliferation, wound healing, focus formation and mamosphere formation assays as well as cell xenografts in nude mice. Phenotypic reverted epithelial cells (RE-cells) obtained after MET induction presented epithelial morphologies and proliferation rates resembling E cells. However, the RE transcriptomic profile and IF staining of epithelial and mesenchymal markers revealed a uniquely heterogeneous mixture of cell subpopulations with a high self-renewal ability. RE cell heterogeneity was stably maintained for long periods after TGFβ1 removal both in vitro and in large tumours derived from the nude mice. Overall, we show that phenotypic reverted epithelial cells (RE cells) do not return to the molecular and functional epithelial state and present mesenchymal features related to aggressiveness and cellular heterogeneity that favour tumour growth in vivo. This work strengthens epithelial cell reprogramming and cellular heterogeneity fostered by inflammatory cues as a tumour growth-promoting factor in vivo.

Identification of key pathways and genes in vestibular schwannoma using bioinformatics analysis

The aim of the present study is to identify novel promising marks and targets of diagnosis, therapy and prognosis for patients with vestibular schwannoma at the molecular level. The gene expression profiles of GSE54934, GSE39645 and GSE56597 datasets were obtained respectively from the Gene Expression Omnibus database. The differentially expressed genes (DEGs) were identified by comparing between gene expression profiles of the vestibular schwannoma tissues and normal tissues. Subsequently, Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis and protein-protein interaction (PPI) network analysis were performed. The function and pathway enrichment analysis were performed for DEGs with DAVID. Reverse transcription-quantitative PCR were conducted to confirm the expression of BCL2, AGT, IL6 and ITGA2 in human Schwann cells and vestibular schwannoma cells. A total of 4,025, 1,1291 and 1,513 DEGs were identified from GSE54934, GSE56597 and GSE39645 datasets, respectively. GO and KEGG analysis showed that the mutual upregulated genes were mainly enriched in cell division, mitotic nuclear division, and transition of mitotic cell cycle, whilst mutual downregulated genes were enriched in chemical synaptic transmission, neurotransmitter transport, and synaptic vesicle membrane. Subsequently, 20 genes, including BCL2, AGT, IL6 and ITGA2 were selected as hub genes with high degrees after PPI network analysis. The significant differential expression of those genes were detected among vestibular schwannoma tissues compared with normal nerve tissues. In conclusion, BCL2, AGT, IL6 and ITGA2 are significantly higher expressed in vestibular schwannoma tissues compared with human Schwann tissues. The DEGs identified in the present study provide novel targets for the diagnosis and treatment of vestibular schwannoma.

Measurement of soluble PD-1 and soluble PD-L1 as well as PD-L1 and PD-1 from perioperative patients with gastric carcinoma

BACKGROUND

Till now, no experiment has been performed to detect programmed death ligand 1 (PD-L1)/programmed death 1 (PD-1), soluble PD-L1/soluble PD-1 simultaneously in perioperative patients of gastric carcinoma. Our experiment aims at determining the clinical significance and possible mechanism of soluble PD-L1/soluble PD-1 in gastric carcinoma.

METHODS

Thirty patients undergone gastrectomy were selected as the experimental group. Tissue's programmed death ligand 1 and peripheral programmed death 1 were detected using immunofluorescence and flow cytometry. Soluble PD-L1 and soluble PD-1 were detected using enzyme-linked immunosorbent assay.

RESULTS

First, preoperative programmed death 1 was higher than control group and decreased to normal post-operatively. Preoperatively ,elevated levels of programmed death 1 on cluster of differentiation (CD)4 T cells indicated less lymphatic metastasis (P < 0.01) and small tumor volume (P < 0.01); elevated programmed death 1 of CD8 T cells indicated big tumor volume (P < 0.01) and well histological differentiation (P < 0.01). Second, preoperative soluble PD-L1 and soluble PD-1 are lower than in control group. Post-operatively, the soluble PD-1 rose to normal, but the soluble PD-L1 showed no change. Third, programmed death ligand 1 can be observed in carcinoma tissue. Fourth, the area under the curve of soluble PD-1 (0.675) for diagnosis was worse than that of soluble PD-L1 (0.885). Kaplan-Meier analysis showed that soluble PD-1 < 245.26 pg/ml in post-operative serum predicted a poor prognosis (overall survival percentage: 60%) at 2 years (P < 0.05). Multivariate analysis revealed that carcinoembryonic antigen (>5 ng/l) and soluble PD-1 after gastrectomy (>245.26 pg/ml) were independent prognostic factors for overall survival (hazard ratio: 20.812, 95% confidence interval: 1.217-355.916, P = 0.036; hazard ratio: 0.028, 95% confidence interval: 0.001-0.786, P = 0.036, respectively).

CONCLUSIONS

We propose that soluble PD-1 combined with programmed death ligand 1 are effective not only in protecting T cells from the adhesion by programmed death ligand 1 but also in preventing the occurrence and the development of tumor as well. Through multivariate analysis, we found that soluble PD-1 was an independent protective factor for post-operative prognosis of gastric carcinoma patients, which indirectly verified the vital function of soluble PD-1. Soluble PD-1 might be promising predictive biomarkers for the diagnosis and prognosis of gastric carcinoma patients.

Identification of a Novel Epithelial-Mesenchymal Transition-Related Gene Signature for Endometrial Carcinoma Prognosis

(1) Background: Endometrial cancer is the most prevalent cause of gynecological malignant tumor worldwide. The prognosis of endometrial carcinoma patients with distant metastasis is poor. (2) Method: The RNA-Seq expression profile and corresponding clinical data were downloaded from the Cancer Genome Atlas database and the Gene Expression Omnibus databases. To predict patients’ overall survival, a 9 EMT-related genes prognosis risk model was built by machine learning algorithm and multivariate Cox regression. Expressions of nine genes were verified by RT-qPCR. Responses to immune checkpoint blockades therapy and drug sensitivity were separately evaluated in different group of patients with the risk model. (3) Endometrial carcinoma patients were assigned to the high- and low-risk groups according to the signature, and poorer overall survival and disease-free survival were showed in the high-risk group. This EMT-related gene signature was also significantly correlated with tumor purity and immune cell infiltration. In addition, eight chemical compounds, which may benefit the high-risk group, were screened out. (4) Conclusions: We identified a novel EMT-related gene signature for predicting the prognosis of EC patients. Our findings provide potential therapeutic targets and compounds for personalized treatment. This may facilitate decision making during endometrial carcinoma treatment.

Cancer Stem Cells and the Tumor Microenvironment in Gastric Cancer

Gastric cancer (GC) remains one of the leading causes of cancer-related death worldwide. Cancer stem cells (CSCs) might be responsible for tumor initiation, relapse, metastasis and treatment resistance of GC. The tumor microenvironment (TME) comprises tumor cells, immune cells, stromal cells and other extracellular components, which plays a pivotal role in tumor progression and therapy resistance. The properties of CSCs are regulated by cells and extracellular matrix components of the TME in some unique manners. This review will summarize current literature regarding the effects of CSCs and TME on the progression and therapy resistance of GC, while emphasizing the potential for developing successful anti-tumor therapy based on targeting the TME and CSCs.

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.

Weighted Gene Co-expression Network Analysis Identifies a Cancer-Associated Fibroblast Signature for Predicting Prognosis and Therapeutic Responses in Gastric Cancer

Background: Cancer-associated fibroblasts (CAFs) are the most prominent cellular components in gastric cancer (GC) stroma that contribute to GC progression, treatment resistance, and immunosuppression. This study aimed at exploring stromal CAF-related factors and developing a CAF-related classifier for predicting prognosis and therapeutic effects in GC.

Methods: We downloaded mRNA expression and clinical information of 431 GC samples from Gene Expression Omnibus (GEO) and 330 GC samples from The Cancer Genome Atlas (TCGA) databases. CAF infiltrations were quantified by the estimate the proportion of immune and cancer cells (EPIC) method, and stromal scores were calculated via the Estimation of STromal and Immune cells in MAlignant Tumors using Expression data (ESTIMATE) algorithm. Stromal CAF-related genes were identified by weighted gene co-expression network analysis (WGCNA). A CAF risk signature was then developed using the univariate and least absolute shrinkage and selection operator method (LASSO) Cox regression model. We applied the Spearman test to determine the correlation among CAF risk score, CAF markers, and CAF infiltrations (estimated via EPIC, xCell, microenvironment cell populations-counter (MCP-counter), and Tumor Immune Dysfunction and Exclusion (TIDE) algorithms). The TIDE algorithm was further used to assess immunotherapy response. Gene set enrichment analysis (GSEA) was applied to clarify the molecular mechanisms.

Results: The 4-gene (COL8A1, SPOCK1, AEBP1, and TIMP2) prognostic CAF model was constructed. GC patients were classified into high– and low–CAF-risk groups in accordance with their median CAF risk score, and patients in the high–CAF-risk group had significant worse prognosis. Spearman correlation analyses revealed the CAF risk score was strongly and positively correlated with stromal and CAF infiltrations, and the four model genes also exhibited positive correlations with CAF markers. Furthermore, TIDE analysis revealed high–CAF-risk patients were less likely to respond to immunotherapy. GSEA revealed that epithelial–mesenchymal transition (EMT), TGF-β signaling, hypoxia, and angiogenesis gene sets were significantly enriched in high–CAF-risk group patients.

Conclusion: The present four-gene prognostic CAF signature was not only reliable for predicting prognosis but also competent to estimate clinical immunotherapy response for GC patients, which might provide significant clinical implications for guiding tailored anti-CAF therapy in combination with immunotherapy for GC patients.

Inhibition of MIR4435-2HG on Invasion, Migration, and EMT of Gastric Carcinoma Cells by Mediating MiR-138-5p/Sox4 Axis

Background

The previous investigations have identified that long non-coding RNA (lncRNAs) act as crucial regulators in gastric carcinoma. However, the function of lncRNA MIR4435-2HG in the modulation of gastric carcinoma remains elusive. Here, we aimed to explore the role of MIR4435-2HG in gastric carcinoma.

Method

The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) were applied to select the differently expressed lncRNAs in gastric carcinoma. The qRT-PCR was applied to analyze MIR4435-2HG expression in carcinoma tissues and cell lines. The effect of MIR4435-2HG on proliferation, invasion, migration, and apoptosis of gastric carcinoma cells was detected by Cell Counting Kit-8 (CCK-8) assays, transwell assays, and flow cytometry in vitro. A subcutaneous tumor model was constructed to examine the tumor growth of gastric carcinoma cells after knocking out MIR4435-2HG. RNA immunoprecipitation and luciferase reporting assays were applied to evaluate the interaction of MIR4435-2HG, miR-138-5p, and Sox4.

Results

The bioinformatics analysis based on TCGA and GEO databases indicated that MIR4435-2HG was obviously elevated in gastric carcinoma samples. The qRT-PCR analysis revealed that MIR4435-2HG was upregulated in clinical gastric carcinoma tissues and cells. The high expression of MIR4435-2HG is associated with the poor survival rate of patients. The knockout of MIR4435-2HG could repress the proliferation, invasion, migration, and epithelial–mesenchymal transition (EMT) and accelerate the apoptosis of gastric carcinoma cells. Moreover, the deletion of MIR4435-2HG was able to attenuate the tumor growth in vivo. Mechanically, we identified that MIR4435-2HG enhanced Sox4 expression by directly interacting with miR-138-5p as a competitive endogenous RNA (ceRNA) in gastric carcinoma cells, in which Sox4 was targeted by miR-138-5p.

Conclusion

MIR4435-2HG is elevated in gastric carcinoma cells and contributes to the growth, metastasis, and EMT of gastric carcinoma cells by targeting miR-138-5p/Sox4 axis. MIR4435-2HG may be applied as a potential therapeutic target in gastric carcinoma.

Emerging therapeutic targets for gastric cancer from a host-Helicobacter pylori interaction perspective

INTRODUCTION

Gastric cancer (GC) has the higher genetic, cytologic, and architectural heterogeneity compared to other gastrointestinal cancers. By inducing gastric inflammation, Helicobacter pylori (HP) may lead to GC through combining bacterial factors with host factors. In this regard, identification of the major therapeutic targets against the host-HP interactions plays a critical role in GC prevention, diagnosis, and treatment.

AREAS COVERED

This study offers new insights into the promising therapeutic targets against the angiogenesis, invasion, or metastasis of GC from a host-HP interaction perspective. To this end, MEDLINE, EMBASE, LILACS, AIM, and IndMed databases were searched for relevant articles since 1992.

EXPERT OPINION

Wnt signaling and COX pathway have a well-documented history in the genesis of GC by HP and might be considered as the most promising targets for early GC treatment. Destroying HP may decrease the risk of GC, but it cannot fully hinder the GC development induced by HP infection. Therefore, targeting HP-activated pathways, especially COX-2/Wnt/beta-catenin/VEGF, TLR2/TLR9/COX-2, COX2-PGE2, and NF-κB/COX-2, as well as EPHA2, MMPs, and miR-543/SIRT1 axis, can be an effective measure in the early treatment of GC. However, different clinical trials and large, multi-center cohorts are required to validate these potentially effective targets for GC therapy.

Epithelial Mesenchymal Transition and Immune Response in Metaplastic Breast Carcinoma

Metaplastic breast carcinoma (MBC) is a heterogeneous group of infrequent triple negative (TN) invasive carcinomas with poor prognosis. MBCs have a different clinical behavior from other types of triple negative breast cancer (TNBC), being more resistant to standard chemotherapy. MBCs are an example of tumors with activation of epithelial–mesenchymal transition (EMT). The mechanisms involved in EMT could be responsible for the increase in the infiltrative and metastatic capacity of MBCs and resistance to treatments. In addition, a relationship between EMT and the immune response has been seen in these tumors. In this sense, MBC differ from other TN tumors showing a lower number of tumor-infiltrating lymphocytes (TILS) and a higher percentage of tumor cells expressing programmed death-ligand 1 (PD-L1). A better understanding of the relationship between the immune system and EMT could provide new therapeutic approaches in MBC.

lncRNAs as Hallmarks for Individualized Treatment of Gastric Cancer

Gastric cancer is global cancer with a high mortality rate. A growing number of studies have found the abnormal expression of lncRNA (long noncoding RNA) in many tumors, which plays a role in promoting or inhibiting cancer. Similarly, lncRNA abnormal expression plays an essential biological function in gastric cancer. This article focuses on lncRNA involvement in the development of gastric cancer in terms of cell cycle disorder, apoptosis inhibition, metabolic remodeling, promotion of tumor inflammation, immune escape, induction of angiogenesis, and epithelial mesenchymal transition (EMT). The involvement of lncRNA in the development of gastric cancer is related to drug resistance, such as cisplatin and multi-drug resistance. It can also be used as a potential marker for the diagnosis and prognosis of gastric cancer and a target for the treatment. With an in-depth understanding of the mechanism of lncRNA in gastric cancer, new ideas for personalized treatment of gastric cancer are expected.

TRAIL promotes epithelial-to-mesenchymal transition by inducing PD-L1 expression in esophageal squamous cell carcinomas

Background

Tumor necrosis factor-associated apoptosis-inducing ligand (TRAIL) was initially considered an immunity guard; however, its function remains controversial. Besides immune cells, lung and colon cancer cells have also been reported to express TRAIL, which can promote tumor invasion and metastasis. However, the biological function and underlying mechanism of action of TRAIL in esophageal squamous cell carcinoma (ESCC) remain poorly elucidated.

Methods

The ESCC cells stemness, migration, and proliferation ability was assessed by sphere formation, Transwell, and CCK8 assay. The stemness- and epithelial-mesenchymal transition (EMT)- related genes expression levels were analyzed by Western blot and RT-qPCR. The signal activation was conducted by Western blot. The xenograft mouse experiments and lung metastasis model were performed to confirm our findings in vitro.

Results

Herein, we found that TRAIL is a negative predictor in patients with ESCC. To further investigate the biological function of TRAIL, we established TRAIL knockdown and overexpression ESCC cell lines and found that TRAIL induced EMT and promoted tumor aggressiveness. Furthermore, we demonstrated that TRAIL- overexpressing cells upregulated PD-L1 expression, which was dependent on the p-ERK/STAT3 signaling pathway. We obtained similar results when using recombinant human TRAIL. Finally, we validated the biological role and mechanism of action of TRAIL in vivo.

Conclusions

These findings demonstrate that TRAIL promotes ESCC progression by enhancing PD-L1 expression, which induces EMT. This may explain the failure of TRAIL preclinical trials.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-021-01972-0.

H. pylori infection induces CXCL8 expression and promotes gastric cancer progress through downregulating KLF4

Tumour-derived CXCL8 facilitates the movement of myeloid-derived suppressor cells, which are able to restrain antitumour immune responses to the tumour microenvironment. Kruppel-like factor 4 (KLF4) is a potential tumour suppressor in gastric cancer (GC). However, knowledge regarding correlations between KLF4 and CXCL8 in GC is limited. We use cellular and molecular biological methods to assess whether these two factors interact in GC. Expression CXCL8 and KLF4 was altered in human GC tissues compared to normal gastric tissues in opposite ways. Additionally, cytotoxin-associated gene A protein (CagA) gene transduction or Helicobacter pylori (H. pylori) infection upregulated CXCL8 expression. Knockdown of KLF4 expression increased CXCL8 protein and RNA expression, whereas its overexpression had the opposite effect. CXCL8-mediated enhancement of GC cell migration and proliferation was reversed by upregulation of KLF4 expression. Further mechanistic research revealed that KLF4 binds the CXCL8 promoter, suppressing CXCL8 transcription. Moreover, CXCL8 stimulation reduced KLF4 protein expression and promoted GC cell proliferation and migration, eventually promoting neoplasm growth in vivo. Together, our findings demonstrate that CagA promotes CXCL8 and inhibits KLF4. CXCL8 is a decisive downstream target gene of KLF4, and KLF4 negatively regulates CXCL8 in GC. Furthermore, CXCL8's negative regulation of KLF4 in vivo and in vitro, indicates that CagA may downregulate KLF4 by inducing CXCL8 expression, low expression of KLF4 further promotes that of CXCL8, forming a vicious circle in GC. Targeted KLF4 activation might improve the immunosuppressive microenvironment through direct negative regulation of CXCL8, providing a new potential target to strengthen the efficacy of immunotherapy in GC patients.

Icariside II: Anticancer Potential and Molecular Targets in Solid Cancers

Icariside II, an active flavonoid, is extracted from the traditional Chinese medicinal herb Epimedii. It possesses multiple biological and pharmacological properties, including anti-inflammatory, anticancer, and anti-osteoporotic properties. In recent years, apoptosis has become the hot spot in anticancer therapies. Icariside II exerts positive effects on inducing apoptosis and inhibiting proliferation in various cancers. The antitumorigenic activity of Icariside II was also proven through cell cycle arrest, triggering autophagy, reducing cellular metabolism, and inhibiting cancer metastasis and tumor-associated angiogenesis. Additionally, Icariside II, as a natural product, contributed to a synergistic effect alongside chemotherapeutic drugs. Due to its poor aqueous solubility and permeability, more strategies were developed to improve its therapeutic effects. This review aimed to summarize the chemopreventive properties of Icariside II in solid tumors and reveal its underlying molecular mechanisms.

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.

Epigenetic Age Acceleration of Stomach Adenocarcinoma Associated With Tumor Stemness Features, Immunoactivation, and Favorable Prognosis

Background: Abnormal DNA methylation (DNAm) age has been assumed to be an indicator for canceration and all-cause mortality. However, associations between DNAm age and molecular features of stomach adenocarcinoma (STAD), and its prognosis have not been systematically studied.

Method: We calculated the DNAm age of 591 STAD samples and 115 normal stomach samples from The Cancer Genome Atlas (TCGA) and gene expression omnibus (GEO) database using the Horvath’s clock model. Meanwhile, we utilized survival analysis to evaluate the prognostic value of DNAm age and epigenetic age acceleration shift. In addition, we performed weighted gene co-expression network analysis (WGCNA) to identify DNAm age-associated gene modules and pathways. Finally, the association between DNAm age and molecular features was performed by correlation analysis.

Results: DNA methylation age was significantly correlated with chronological age in normal gastric tissues (r = 0.85, p < 0.0001), but it was not associated with chronological age in STAD samples (r = 0.060, p = 0.2369). Compared with tumor adjacent normal tissue, the DNAm age of STAD tissues was significantly decreased. Meanwhile, chronological age in STAD samples was higher than its DNAm age. Both DNAm age and epigenetic acceleration shift were associated with the prognosis of STAD patients. By using correlation analysis, we also found that DNAm age was associated with immunoactivation and stemness in STAD samples.

Conclusion: In summary, epigenetic age acceleration of STAD was associated with tumor stemness, immunoactivation, and favorable prognosis.

Emerging role of tumor cell plasticity in modifying therapeutic response

Resistance to cancer therapy is a major barrier to cancer management. Conventional views have proposed that acquisition of resistance may result from genetic mutations. However, accumulating evidence implicates a key role of non-mutational resistance mechanisms underlying drug tolerance, the latter of which is the focus that will be discussed here. Such non-mutational processes are largely driven by tumor cell plasticity, which renders tumor cells insusceptible to the drug-targeted pathway, thereby facilitating the tumor cell survival and growth. The concept of tumor cell plasticity highlights the significance of re-activation of developmental programs that are closely correlated with epithelial-mesenchymal transition, acquisition properties of cancer stem cells, and trans-differentiation potential during drug exposure. From observations in various cancers, this concept provides an opportunity for investigating the nature of anticancer drug resistance. Over the years, our understanding of the emerging role of phenotype switching in modifying therapeutic response has considerably increased. This expanded knowledge of tumor cell plasticity contributes to developing novel therapeutic strategies or combination therapy regimens using available anticancer drugs, which are likely to improve patient outcomes in clinical practice.

Celastrus Orbiculatus Extracts Inhibit the Metastasis through Attenuating PI3K/Akt/mTOR Signaling Pathway in Human Gastric Cancer

BACKGROUND

Rapamycin receptor inhibitors have been applied in the clinic and achieved satisfactory therapeutic effect recently. The mechanisms did not clearly show how the Celastrus Orbiculatus Extracts (COE) inhibited the expression of the mammalian Target of Rapamycin (mTOR) in human gastric cancer cells. The aim of this study was to investigate whether the COE inhibited the metastasis through the mTOR signaling pathway in human gastric cancer MGC-803 cells.

METHODS

The abnormal expression level of mTOR protein was detected by immunohistochemistry in human gastric cancer tissue. The MGC-803/mTOR- cells were constructed by knockdown of mTOR using lentivirus infection technique. The human gastric cancer MGC-803/mTOR- cells were treated with different concentrations (20, 40, 80 μg/ml) of COE for 24 hours. The ability of cell metastasis was analyzed by the cell invasion and migration assay. The expression levels of PI3K/Akt/mTOR signaling pathway were detected by Western Blotting.

RESULTS

COE inhibited the proliferation, invasion and migration of MGC-803/mTOR- cells in a concentrationdependent manner. The expression of E-cadherin protein increased, and the expression of N-cadherin and Vimentin decreased simultaneously in the MGC-803/mTOR- cells. 4EBP1, p-4EBP1, P70S6k, p-P70S6k, mTOR, p-mTOR, PI3K and Akt proteins in MGC-803/mTOR- cells were reduced in a dose-dependent manner.

CONCLUSION

COE could not only inhibit cell growth, invasion and migration, but also inhibit the epithelialmesenchymal transition of gastric cancer cells. The molecular mechanism of COE inhibited the metastasis which may be related to the PI3K/Akt/mTOR signal pathway. This study provides ideas for the development of new anti-gastric cancer drugs.

Expression of Angiogenic Proteins in Tumor and Stroma Affects Survival in Patients With Gastric Cancer

BACKGROUND

Gastric cancer is one of the most frequent malignancies worldwide. Angiogenic growth factors play a crucial role in mediating the crosstalk between cancer cells and the surrounding microenvironment. In this exploratory study, we investigate the impact of angiogenic proteins within the tumor cell or stroma compartment on survival of patients with gastric cancer.

MATERIALS AND METHODS

In 29 patients, tumor and stromal compartments were separated using laser capture microdissection. Angiogenic protein expression was measured using a bead-based immunoassay and correlated with tumor stage and overall survival.

RESULTS

Overall survival was significantly shorter in patients with a high stroma concentration of vascular endothelial growth factor (VEGF)-A (23.5 (±17.6) versus 33.6 (±21.0) mo; P = 0.009) and stem cell factor (22.2 (±18.5) versus 33.6 (±21.8) mo; P = 0.01) compared with patients with a low stroma concentration. High stromal VEGF-D showed a trend toward worse survival (26.8 (±22.0) versus 37.2 (±19.0) mo; P = 0.09). We did not observe any significant correlation between tumor-specific expression of angiogenic cytokines and survival.

CONCLUSIONS

This translational study highlights the difference in clinical impact between tumor and stromal expression of angiogenic proteins. Compartment-specific concentrations of VEGF-A and stem cell factor affect the clinical prognosis and help to identify the best therapy for patients with gastric cancer.

Mechanisms of the Epithelial-Mesenchymal Transition and Tumor Microenvironment in Helicobacter pylori-Induced Gastric Cancer

Helicobacter pylori (H. pylori) is one of the most common human pathogens, affecting half of the world’s population. Approximately 20% of the infected patients develop gastric ulcers or neoplastic changes in the gastric stroma. An infection also leads to the progression of epithelial–mesenchymal transition within gastric tissue, increasing the probability of gastric cancer development. This paper aims to review the role of H. pylori and its virulence factors in epithelial–mesenchymal transition associated with malignant transformation within the gastric stroma. The reviewed factors included: CagA (cytotoxin-associated gene A) along with induction of cancer stem-cell properties and interaction with YAP (Yes-associated protein pathway), tumor necrosis factor α-inducing protein, Lpp20 lipoprotein, Afadin protein, penicillin-binding protein 1A, microRNA-29a-3p, programmed cell death protein 4, lysosomal-associated protein transmembrane 4β, cancer-associated fibroblasts, heparin-binding epidermal growth factor (HB-EGF), matrix metalloproteinase-7 (MMP-7), and cancer stem cells (CSCs). The review summarizes the most recent findings, providing insight into potential molecular targets and new treatment strategies for gastric cancer.

Immunological Aspects of the Tumor Microenvironment and Epithelial-Mesenchymal Transition in Gastric Carcinogenesis

Infection with Helicobacter pylori, a Gram-negative, microaerophilic pathogen often results in gastric cancer in a subset of affected individuals. This explains why H. pylori is the only bacterium classified as a class I carcinogen by the World Health Organization. Several studies have pinpointed mechanisms by which H. pylori alters signaling pathways in the host cell to cause diseases. In this article, the authors have reviewed 234 studies conducted over a span of 18 years (2002-2020). The studies investigated the various mechanisms associated with gastric cancer induction. For the past 1.5 years, researchers have discovered new mechanisms contributing to gastric cancer linked to H. pylori etiology. Alongside alteration of the host signaling pathways using oncogenic CagA pathways, H. pylori induce DNA damage in the host and alter the methylation of DNA as a means of perturbing downstream signaling. Also, with H. pylori, several pathways in the host cell are activated, resulting in epithelial-to-mesenchymal transition (EMT), together with the induction of cell proliferation and survival. Studies have shown that H. pylori enhances gastric carcinogenesis via a multifactorial approach. What is intriguing is that most of the targeted mechanisms and pathways appear common with various forms of cancer.

Communication between EMT and PD-L1 signaling: New insights into tumor immune evasion

Immune checkpoint blockage has been considered a breakthrough in cancer treatment, achieving encouraging anti-tumor effects in some advanced solid malignancies. However, low response rate and therapeutic resistance represent significant challenges in this field. In addition to its typical role in embryonic development and tissue fibrosis, epithelial-mesenchymal transition (EMT) plays a pivotal role in tumor immunosuppression and immune evasion. Previous studies revealed that EMT is associated with activation of different immune checkpoint molecules, including PD-L1. EMT-induced immune escape promotes cancer progression and may also provide a platform for discovery of novel therapeutic approaches and predictive biomarkers for checkpoint inhibitor therapeutic response. Here, we summarize recent findings focused on EMT-induced immune suppression and evasion in the tumor microenvironment (TME). EMT transcription factors (EMT-TFs), immune cells, cell plasticity and their regulatory role in the immune response are thoroughly reviewed. Bidirectional regulation between EMT and PD-L1 signaling is discussed in terms of cancer immune escape and possible combined therapies. Additionally, we investigated the value of preclinical or clinical trials using EMT targeted therapy combined with PD-L1 inhibitors. This review may help to further understand the role of EMT and PD-L1 signaling in cancer immune evasion. Meanwhile, additional molecular mechanistic studies and clinical trials are urgently needed.

Patient-Derived Xenograft Models of Breast Cancer and Their Application

Recently, patient-derived xenograft (PDX) models of many types of tumors including breast cancer have emerged as a powerful tool for predicting drug efficacy and for understanding tumor characteristics. PDXs are established by the direct transfer of human tumors into highly immunodeficient mice and then maintained by passaging from mouse to mouse. The ability of PDX models to maintain the original features of patient tumors and to reflect drug sensitivity has greatly improved both basic and clinical study outcomes. However, current PDX models cannot completely predict drug efficacy because they do not recapitulate the tumor microenvironment of origin, a failure which puts emphasis on the necessity for the development of the next generation PDX models. In this article, we summarize the advantages and limitations of current PDX models and discuss the future directions of this field.

Role of Cancer-Associated Fibroblast in Gastric Cancer Progression and Resistance to Treatments

Although the survival of gastric cancer (GC) patients has gradually improved, the outcomes of advanced GC patients remain unsatisfactory despite standard treatment with conventional chemotherapy or targeted agents. Several studies have shown that cancer-associated fibroblasts (CAFs), a major component of tumor stroma in GC, may have significant roles in GC progression and resistance to treatments. CAFs are a major source of various secreted molecules in the tumor microenvironment, which stimulate cancer cells and other noncancerous components of GC. Surprisingly, these factors could be involved in gastric carcinogenesis. Cytokines, including interleukin-6 and interleukin-11, or growth factors, such as fibroblast growth factor produced from CAFs, can directly activate GC cells and consequently lead to the development of an aggressive phenotype. Galectin-1 or hepatocyte growth factor can be involved in CAF-derived neovascularization in GC. In addition, recent studies showed that CAFs can affect tumor immunity through M2 polarization of tumor-associated macrophages. Finally, the current study aimed to introduce several inhibitory agents and evaluate their suppressive effects on CAFs in patients with GC progression. However, further studies are required to evaluate their safety and select appropriate patients for application in clinical settings.

The Role of TGF-β and Its Receptors in Gastrointestinal Cancers

Early detection of gastrointestinal tumors improves patient survival. However, patients with these tumors are typically diagnosed at an advanced stage and have poor prognosis. The incidence and mortality of gastrointestinal cancers, including esophageal, gastric, liver, colorectal, and pancreatic cancers, are increasing worldwide. Novel diagnostic and therapeutic agents are required to improve patient survival and quality of life. The tumor microenvironment, which contains nontumor cells, signaling molecules such as growth factors and cytokines, and extracellular matrix proteins, plays a critical role in cancer cell proliferation, invasion, and metastasis. Transforming growth factor beta (TGF-β) signaling has dual roles in gastrointestinal tumor development and progression as both a tumor suppressor and tumor promoter. Here, we review the dynamic roles of TGF-β and its receptors in gastrointestinal tumors and provide evidence that targeting TGF-β signaling may be an effective therapeutic strategy.

Association between Polymorphisms in Inflammatory Response-Related Genes and the Susceptibility, Progression and Prognosis of the Diffuse Histological Subtype of Gastric Cancer

The chronic inflammatory microenvironment and immune cell dysfunction have been described as critical components for gastric tumor initiation and progression. The diffuse subtype is related to poor clinical outcomes, pronounced inflammation, and the worst prognosis. We investigated the association of polymorphisms in inflammatory response-related genes (COX-2, OGG1, TNFB, TNFA, HSPA1L, HSPA1B, VEGFA, IL17F, LGALS3, PHB, and TP53) with gastric cancer susceptibility, progression and prognosis in a Brazilian sample, focusing on the diffuse subtype. We also performed the analysis regarding the total sample of cases (not stratified for tumor subtypes), allowing the comparison between the findings. We further investigated the polymorphisms in linkage disequilibrium and performed haplotype association analyses. In the case-control study, rs1042522 (TP53) was associated with a stronger risk for developing gastric cancer in the sample stratified for diffuse subtype patients when compared to the risk observed for the total cases; CTC haplotype (rs699947/rs833061/rs2010963 VEGFA) was associated with risk while rs699947 was associated with protection for gastric malignancy in the total sample. Regarding the associations with the clinicopathological features of gastric cancer, for the diffuse subtype we found that rs699947 and rs833061 (VEGFA) were associated with outcomes related to a worse progression while rs5275 (COX-2), rs909253 (TNFB), and rs2227956 (HSPA1L) were associated to a better progression of the disease. In the total sample, rs699947 and rs833061 (VEGFA), rs4644 (LGALS3), and rs1042522 (TP53) were able to predict a worse progression while rs5275 (COX-2), rs2227956 (HSPA1L), and rs3025039 (VEGFA) a better progression. Besides, rs909253 (TNFB) predicted protection for the overall and disease-free survivals for gastric cancer. In conclusion, these results helped us to clarify the potential role of these polymorphisms in genes involved in the modulation of the inflammatory response in the pathogenesis of gastric cancer.

Intensive formation of coccoid forms as a feature strongly associated with highly pathogenic Helicobacter pylori strains

The variability of Helicobacter pylori morphology and the heterogeneity of virulence factors expressed by these bacteria play a key role as a driving force for adaptation to the hostile stomach environment. The aim of the study was to determine the relationship between the presence of certain genes encoding virulence factors and H. pylori morphology. One reference and 13 clinical H. pylori strains with a known virulence profile (vacA, cagA, babA2, dupA, and iceA) were used in this study. Bacteria were cultured for 1 h and 24 h in stressogenic culture conditions, i.e., serum-free BHI broths at suboptimal conditions (room temperature and atmosphere, without shaking). H. pylori cell morphology was observed by light and scanning electron microscopy. The vacA polymorphism and the cagA and babA2 presence were positively correlated with the reduction in cell size. Exposure to short-time stressogenic conditions caused more intense transformation to coccoid forms in highly pathogenic H. pylori type I strains (35.83% and 47.5% for type I s1m2 and I s1m1, respectively) than in intermediate-pathogenic type III (8.17%) and low pathogenic type II (9.92%) strains. The inverse relationship was observed for the number of rods, which were more common in type III (46.83%) and II (48.42%) strains than in type I s1m2 (19.25%) or I s1m1 (6.58%) strains. Our results suggest that there is a close relationship between the presence of virulence genes of H. pylori strains and their adaptive morphological features.

ITGAE Defines CD8+ Tumor-Infiltrating Lymphocytes Predicting a better Prognostic Survival in Colorectal Cancer

Background

Tumor-infiltrating lymphocytes (TIL) in colorectal tumor tissue are significantly correlated with a favorable prognosis, such as CD8+ lymphocytes, which are also called tumor-reactive lymphocytes. However, not all tumor-infiltrating T cells confer benefit to patients. Therefore, it is of substantial benefit to identify a biomarker to demarcate these tumor-reactive lymphocytes.

Methods

We investigated whether ITGAE could be used to discriminate reactive CD8+ lymphocytes in colorectal cancer (CRC). TCGA colorectal cancer data sets (n1 = 492, n2 = 386) and FUSCC set (n3 = 276) were used in this study. Further phenotyping of ITGAE+ cells and the mechanistic basis were investigated.

Findings

In the training and testing sets from TCGA, ITGAE expression, which is strongly correlated with cytotoxic T cell markers (CD8/CD3/PD1), independently predicted longer disease-free survival (DFS) and overall survival (OS). In line with this, the association between ITGAE+ lymphocytes and survival has been confirmed in the FUSCC cohort for validation (P = .026). ITGAE + cells in the series always co-stained with CD8 were preferentially located in the tumor. Interestingly, ITGAE+ lymphocytes tended to associate with the epithelial–mesenchymal transition (EMT) with decreased Snail and increased E-cadherin expression accompanied. Finally, gene set enrichment analysis showed that immune activation was significantly enriched in the high ITGAE+ TIL group, accompanied by enriched EMT-related pathways.

Interpretation

Because of the specified expression of tumor-reactive CD8+ T-cells, ITGAE may be a promising biomarker for the rapid identification of immune infiltration in CRC.

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ITGAE expression independently predicted longer disease-free survival (DFS) and overall survival (OS) in colorectal cancers.

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ITGAE could be used to discriminate CD8+ TIL populations

We demonstrate here in colorectal cancers for the first time that ITGAE+ CD8+ lymphocytes infiltration plays a vital role in the antitumor immune response and ITGAE has been identified as a biomarker of tumor-reactive CD8+ TIL. In mechanism, ITGAE+ lymphocytes may even associate with interferon-response chemokines and EMT signaling, then serves as an independent predictor in colorectal cancers.

Tumor-associated macrophage-derived cytokines enhance cancer stem-like characteristics through epithelial-mesenchymal transition

Cancer stem cells are a small population of cells with the potential for self-renewal and multi-directional differentiation and are an important source of cancer initiation, treatment resistance, and recurrence. Epithelial-mesenchymal transition (EMT) is a process in which epithelial cells lose their epithelial phenotype and convert to mesenchymal cells. Recent studies have shown that cancer cells undergoing EMT can become stem-like cells. Many kinds of tumors are associated with chronic inflammation, which plays a role in tumor progression. Among the various immune cells mediating chronic inflammation, macrophages account for ~30%-50% of the tumor mass. Macrophages are highly infiltrative in the tumor microenvironment and secrete a series of inflammatory factors and cytokines, such as transforming growth factor (TGF)-β, IL-6, IL-10, and tumor necrosis factor (TNF)-α, which promote EMT and enhance the stemness of cancer cells. This review summarizes and discusses recent research findings on some specific mechanisms of tumor-associated macrophage-derived cytokines in EMT and cancer stemness transition, which are emerging targets of cancer treatment.

Relationship between infiltrating lymphocytes in cancerous ascites and dysfunction of Cajal mesenchymal cells in the small intestine

Malignant ascites changes the microenvironment of the peritoneal cavity and damages abdominal functional host cells such as interstitial cells of Cajal (ICC), causing gastrointestinal dysfunction and poor prognosis. Besides tumor cells, malignant ascites contains large numbers of lymphocytes and macrophagocytes. These inflammatory cells act as a 'double arrow' and it is not clear whether they cause injury to ICCs. Our study demonstrates the presence of T lymphocytes in malignant ascites and shows that these cells may have a critical role in inducing damage to ICC via Caspases and Fas/FasL. These inflammatory cells were contributory to gastric dysfunction in our GI tumor-induced ascites mouse models.

Hypoxia Enhances Fusion of Oral Squamous Carcinoma Cells and Epithelial Cells Partly via the Epithelial-Mesenchymal Transition of Epithelial Cells

Increasing evidence and indications showed that cell fusion is crucial in tumor development and metastasis, and hypoxia, a closely linked factor to tumor microenvironment, which can lead to EMT, induces angiogenesis and metastasis in tumor growth. However, the relationship between hypoxia and fusion has not been reported yet. EMT will change some proteins in the epithelial cell surface and the changes of proteins in cell surface may increase cell fusion. This study found that hypoxia promotes the spontaneous cell fusion between Oral Squamous Carcinoma Cells (OSCCs) and Human Immortalized Oral Epithelial Cells (HIOECs). At the same time, Hypoxia can lead to EMT, and hypoxia-pretreated HIOECs increased fusion rate with OSCC, while the fusion rate was significantly reduced by DAPT, a kind of EMT blocker. Therefore, epithelial cells can increase spontaneously cell fusion with OSCC by EMT. Our study may provide a new insight to link among tumor microenvironment, cell fusion, and cancer.

The role of cancer-associated fibroblast MRC-5 in pancreatic cancer

Background: Our previous study showed that cancer-associated fibroblast MRC-5 promoted hepatocellular carcinoma progression by enhancing migration and invasion capability. However, few studies have explored the role of MRC-5 in pancreatic cancer (PC). In this study, we examined the exact role and associated mechanisms of MRC-5. Methods: The conditioned media for MRC-5 was used to culture PC cell lines SW1990 and PANC-1. Cell proliferation was compared based on colony formation assays of PC cells in normal media and of PC cells cultured with conditioned media of MRC-5. Cell migration and invasion were assayed by transwell chambers. The expression of EMT-related proteins and apoptosis-related proteins was evaluated using Western blot. And confocal microscopy was used to further detect the expression of EMT-related proteins. qRT-PCR was used to confirm the expression changes of related genes at the mRNA level. We also used flow cytometry to examine the cell cycle, apoptotic rate, and expression of CD3, CD4, CD14, CD25, CD45, CD61, CD90, TLR1, and TLR4. Results: MRC-5 repressed the colony formation ability of PC cells and significantly inhibited cell migration and invasion potential. MRC-5 induced S-phase cell cycle arrest but did not augment the apoptotic effects in PC cells. We hypothesized that the weakened malignant biological behavior of PC cells was correlated with MRC-5-induced altered expression of the cancer stem cell marker CD90; the immune-related cell surface molecules CD14, CD25, TLR4, and TLR1; and cell polarity complexes Par, Scribble, and Crumbs. Conclusion: MRC-5 limits the malignant activities of PC cells by suppressing cancer stem cell expansion, remolding epithelial polarity, and blocking the protumoral cascade reaction coupled to TLR4, TLR1, CD14, and CD25.

Tumor-associated macrophages remodeling EMT and predicting survival in colorectal carcinoma

The immune contexture, a composition of the tumor microenvironment, plays multiple important roles in cancer stem cell (CSC) and epithelial-mesenchymal transition (EMT), and hence critically influences tumor initiation, progression and patient outcome. Tumor-associated macrophages (TAMs) are abundant in immune contexture, however their roles in CSC, EMT and prognosis of colorectal cancer (CRC) have not been elucidated. In 419 colorectal carcinomas, immune cell types (CD68⁺ macrophages, CD3⁺, CD4⁺ or CD8⁺ T lymphocytes, CD20⁺ B lymphocytes), EMT markers (E-cadherin and Snail) as well as the stem cell marker (CD44v6) were detected in tumor center (TC) and tumor invasive front (TF) respectively by immunohistochemistry. Tumor buds, that represent EMT phenotype, were also counted. It was found CD68⁺ macrophages were the most infiltrating immune cells in CRC. By correlation analysis, more CD68⁺_TF macrophages were associated with more CD44v6 expression (p < 0.001), lower Snail_TF expression (p = 0.08) and fewer tumor buds (p < 0.001). More CD68⁺_TF macrophages were significantly related to more CD3⁺_TF T lymphocytes (p = 0.002), CD8⁺_TF T lymphocytes (p < 0.001) and CD20⁺_TF B lymphocytes counts (p = 0.004). Strong CD68⁺_TF macrophages infiltration also predicted long term overall survival. CRC patients with more tumor buds had worse survival. However, strong CD68⁺_TF macrophages infiltration could reverse the unfavorable results since patients with more tumor buds but increasing CD68⁺_TF macrophages infiltration had the favorable outcome, similar to lower tumor buds groups. This study provided direct morphological evidence that tumor-associated macrophages in the invasive front play critical roles in fighting with the unfavorable results of tumor buds, thus resulting favorable outcomes for CRC patients.

Interaction with neutrophils promotes gastric cancer cell migration and invasion by inducing epithelial-mesenchymal transition

Emerging evidence has revealed that neutrophils have phenotypic and functional plasticity. Neutrophils could be polarized towards a pro-tumor phenotype by tumor-derived factors. In the present study, we investigated the role of the interaction with neutrophils on the functions of gastric cancer cells in vitro. Human promyelocytic leukemia HL-60 cells were induced to differentiate into neutrophil-like cells (HL-60N) using dimethyl sulfoxide (DMSO). Human gastric cancer cells were co-cultured with HL-60N cells or treated with the conditioned medium (CM) of cancer-activated HL-60N cells. The migration and invasion of gastric cancer cells were significantly enhanced while their proliferation was minimally altered. The expression of pro-inflammatory factors including IL-6, IL-8, IL-1β, and TNFα was significantly increased in cancer-activated HL-60N cells, which induced the activation of the ERK pathway and epithelial-mesenchymal transition (EMT) in gastric cancer cells. Blocking the ERK pathway activation reversed the promoting effects of cancer-activated HL-60N cells on gastric cancer cell migration and invasion. In addition, mouse gastric cancer cell derived CM could also increase the expression of pro-inflammatory factors in mouse bone marrow neutrophils, which in turn enhanced the migration and invasion of mouse gastric cancer cells. Collectively, our findings revealed that the interaction with neutrophils promoted gastric cancer cell migration and invasion through the activation of the ERK pathway and the induction of EMT, indicating that neutrophils may play an important role in gastric cancer metastasis. Therefore, targeting neutrophil-cancer cell interaction may provide a new strategy for the treatment of gastric cancer.

PD-1 and PD-L1 co-expression predicts favorable prognosis in gastric cancer

While the prognosis of gastric cancer (GC) remains poor, PD-1 and PD-L1/L2 are promising prognostic biomarkers. We evaluated PD-1 and PD-L1/L2 expression in tumor cells (TCs) and tumor-infiltrating immune cells (TIICs). We determined the Helicobacter pylori (Hp) and Epstein-Barr virus (EBV) infection status in a GC cohort (n=340), then analyzed the relationship between the expression of PD-1, PD-L1/L2 and GC prognosis. We found that PD-1, PD-L1, and PD-L2 mRNA levels were up-regulated in GC tissues, and were positively correlated with one another (P=0.043, P=0.008 and P=0.035). PD-1 protein expression in TIICs was observed in 22.6% of GC patients. The PD-L1 and PD-L2 positivity rates were 40.3% and 53.8% in TCs, respectively, and 60.0% and 60.9% in TIICs, respectively. PD-L1 was up-regulated in EBV-infected GC patients in both TCs (P=0.009) and TIICs (P=0.003). Hp status was not associated with PD-1 or PD-L1/PD-L2 expression. In TIICs, PD-L1 expression was independently associated with better GC prognosis (HR=0.72, 95%CI: 0.53-0.99). Co-expression of PD-1 and PD-L1, but not PD-L2, was a favorable prognostic marker that indicated a dose effect on the mortality risk of GC patients (P-value for trend=0.005). Comprehensive evaluation of PD-1 and PD-L1 in TCs and TIICs could help predict the prognosis of gastric cancers, as well as reveal patients who might benefit from targeted treatment.

Low expression of hsa_circ_0006633 in human gastric cancer and its clinical significances

Circular RNAs are new type of endogenous RNAs, which play an important role in the regulation of gene expression and indicate a great capacity in clinical diagnosis and treatments of diseases. However, the role of circular RNAs in gastric cancer remains unknown. In this study, we chose hsa_circ_0006633 as the target circular RNA and measured its levels in human gastric cancer tissues, plasma, and gastric cell lines by real-time quantitative reverse transcription polymerase chain reaction. Hsa_circ_0006633 levels at multiple stages of gastric tumorigenesis were then explored, and its relationships with clinicopathological features were analyzed as well. We found that the expression levels of hsa_circ_0006633 in four gastric cancer cell lines, HGC-27, SGC-7901, MGC-803, and AGS, were downregulated than those in normal gastric mucosal epithelial cell line GES-1. Then, we further detected that it was downregulated in 79.2% (76/96) gastric cancer tissues compared with the adjacent non-tumorous tissues. The lower expression of hsa_circ_0006633 was associated with cancer distal metastasis ( p = 0.037) and tissue carcinoembryonic antigen level ( p = 0.041). In addition, hsa_circ_0006633 expression was significantly decreased in gastritis and dysplasia tissues comparing with the healthy control. Moreover, plasma hsa_circ_0006633 levels were significantly increased in gastric cancer compared with healthy control. Our data imply that hsa_circ_0006633 may play an important role in gastric carcinogenesis and is also a potential biomarker for screening gastric cancer.