Tumor-infiltrating CD4+ T cells in patients with gastric cancer

Ascites-derived hsa-miR-181a-5p serves as a prognostic marker for gastric cancer-associated malignant ascites

BACKGROUND

Peritoneal carcinomatosis was the main reason leading to gastric cancer (GC)-related death. We aimed to explore the roles of dysregulated microRNAs (miRNAs) and related immune regulation activities in GC-associated malignant ascites.

METHODS

GSE126399 were downloaded from GEO database. Differentially expressed miRNAs in GC ascites samples was firstly screened, and critical miRNAs were further investigated by LASSO (least absolute shrinkage and selection operator) logistic regression and random forest (RF) algorithm. Receiver operating characteristic of critical miRNAs was also constructed. Moreover, functional analysis, immune cell infiltration associated with differentially expressed mRNAs were further analyzed. After selecting key modules by weighted gene co-expression network analysis, mRNAs related with survival performance and transcription factor (TF)-miRNA-mRNA network were constructed.

RESULTS

Hsa-miR-181b-5p was confirmed as critical differentially expressed miRNAs in GC ascites. Then, the tumor samples were divided into high- and low- expression groups divided by mean expression levels of hsa-miR-181b-5p, and subjects with high hsa-miR-181b-5p levels had better survival outcomes. In total, 197 differentially expressed mRNAs associated with hsa-miR-181b-5p levels were obtained, and these mRNAs were mainly enriched in muscle activity and vascular smooth muscle contraction. Hsa-miR-181b-5 was positively related with activated CD4 T cells and negatively related with eosinophil. 17 mRNAs were selected as mRNAs significantly related with prognosis of GC, such as PDK4 and RAMP1. Finally, 75 TF-miRNA-mRNA relationships were obtained, including 15 TFs, hsa-miR-181b-5p, and five mRNAs.

CONCLUSION

Our data suggest that the differentially expressed hsa-miR-181b-5p in ascites samples of GC patients may be a valuable prognostic marker and a potential target for therapeutic intervention, which should be validated in the near future.

Regulation and impact of tumor-specific CD4+ T cells in cancer and immunotherapy

CD4+ T cells are crucial in generating and sustaining immune responses. They orchestrate and fine-tune mammalian innate and adaptive immunity through cell-based interactions and the release of cytokines. The role of these cells in contributing to the efficacy of antitumor immunity and immunotherapy has just started to be uncovered. Yet, many aspects of the CD4+ T cell response are still unclear, including the differentiation pathways controlling such cells during cancer progression, the external signals that program them, and how the combination of these factors direct ensuing immune responses or immune-restorative therapies. In this review, we focus on recent advances in understanding CD4+ T cell regulation during cancer progression and the importance of CD4+ T cells in immunotherapies.

Evolving perspectives regarding the role of the PD-1/PD-L1 pathway in gastric cancer immunotherapy

Gastric cancer (GC) is an increasing global health problem and is one of the leading cancers worldwide. Traditional therapies, such as radiation and chemotherapy, have made limited progress in enhancing their efficacy for advanced GC. The development of immunotherapy for advanced GC has considerably improved with a deeper understanding of the tumor microenvironment. Immunotherapy using checkpoint inhibitors is a new therapeutic option that has made substantial advances in the treatment of other malignancies and is increasingly used in other clinical oncology treatments. Particularly, therapeutic antibodies targeting the programmed cell death protein-1 (PD-1)/programmed cell death ligand 1 (PD-L1) pathway have been effectively used in the clinical treatment of cancer. Monoclonal antibodies blocking the PD-1/PD-L1 pathway have been developed for cancer immunotherapy to enhance T cell function to restore the immune response and represent a breakthrough in the treatment of GC. This review provides an outline of the progress of PD-1/PD-L1 blockade therapy and its expression characteristics and clinical application in advanced GC.

The role of CD4+ T cells in tumor and chronic viral immune responses

Immunotherapies are mainly aimed to promote a CD8+ T cell response rather than a CD4+ T cell response as cytotoxic T lymphocytes (CTLs) can directly kill target cells. Recently, CD4+ T cells have received more attention due to their diverse roles in tumors and chronic viral infections. In antitumor and antichronic viral responses, CD4+ T cells relay help signals through dendritic cells to indirectly regulate CD8+ T cell response, interact with B cells or macrophages to indirectly modulate humoral immunity or macrophage polarization, and inhibit tumor blood vessel formation. Additionally, CD4+ T cells can also exhibit direct cytotoxicity toward target cells. However, regulatory T cells exhibit immunosuppression and CD4+ T cells become exhausted, which promote tumor progression and chronic viral persistence. Finally, we also outline immunotherapies based on CD4+ T cells, including adoptive cell transfer, vaccines, and immune checkpoint blockade. Overall, this review summarizes diverse roles of CD4+ T cells in the antitumor or protumor and chronic viral responses, and also highlights the immunotherapies based on CD4+ T cells, giving a better understanding of their roles in tumors and chronic viral infections.

PHF5A facilitates the development and progression of gastric cancer through SKP2-mediated stabilization of FOS

BACKGROUND

Gastric cancer (GC) is the fifth most common cancer and the third most common cause of cancer death worldwide. Plant homeodomain (PHD)-finger domain protein PHF5A has been demonstrated to play a promoting role in a variety of cancers. This study aimed to clarify the role of PHF5A in the progression of GC and its potential mechanism of action.

METHODS

Immunohistochemical staining experiments were performed based on tissues from clinical GC patients to reveal PHF5A expression. A series of functional experiments in vitro and in vivo were used to clarify the role of PHF5A in GC.

RESULTS

Clinically, PHF5A was abundantly expressed in GC and existed clinical value indicating poor prognosis. In addition, GC cells with knockdown of PHF5A expression showed slowed proliferation, enhanced sensitivity to apoptosis and inhibition of migration. Mechanically, knockdown of PHF5A led to decreased protein stability of FOS, which was mediated ubiquitination of E3 ubiquitin ligase S-phase kinase-associated protein 2 (SKP2). Moreover, downregulation of FOS attenuated the promotion of PHF5A overexpression on GC cells. Consistently, Pladienolide B (PHF5A inhibitor) treatment reversed the induction of PHF5A overexpression on the malignant phenotypes and tumor formation of GC cells.

CONCLUSION

Knockdown of PHF5A inhibited the progression of GC through SKP2-mediated ubiquitination of FOS, which may be a promising candidate target with potential therapeutic value.

Integrated analysis from multicentre studies identities m7G-related lncRNA-derived molecular subtypes and risk stratification systems for gastric cancer

Introduction

Gastric cancer (GC) is the fourth leading cause of cancer death worldwide. Due to the lack of effective chemotherapy methods for advanced gastric cancer and poor prognosis, the emergence of immunotherapy has brought new hope to gastric cancer. Further research is needed to improve the response rate to immunotherapy and identify the populations with potential benefits of immunotherapy. It is unclear whether m7G-related lncRNAs influence tumour immunity and the prognosis of immunotherapy.

Methods

This study evaluated 29 types of immune cells and immune functions in gastric cancer patients, and m7G-related lncRNAs and their molecular subtypes were identified. In addition, we also studied the biological function characteristics of m7G-related lncRNA molecular subtypes. Finally, the patient's risk score was calculated based on m7G-related lncRNAs, and a nomogram of staging and risk groups was established to predict the prognosis. For experimental verification, RT-qPCR were preformed from the native cohort.

Results

After identifying m7G-related lncRNAs and their molecular subtypes, we found three molecular subtypes, the B subtype had the highest level of infiltration, and the B subtype may benefit more from immunotherapy. We divided GC patients into two regulator subtypes based on biological function. The two subtypes have significant immunological differences and can be used to judge ICI treatment. We established a risk score formula based on five lncRNAs, including LINC00924, LINC00944, LINC00865, LINC00702, and ZFAS1. Patients with poor prognoses were closely related to patients in the high-risk group. After comprehensive analysis of different risk groups, the efficacy of the high-risk group on bleomycin, cisplatin, docetaxel, doxorubicin and etoposide was better than that of the low-risk group, suggesting that risk subgroups based on risk scores play a guiding role in chemotherapy and that the high-risk group may benefit more from immunotherapy. RT-qPCR results showed that LINC00924, LINC00944, and LINC00865 were highly expressed in tumour tissues, while LINC00702 and ZFAS1 were expressed at low levels in tumour tissues.

Discussion

In conclusion, we were the first to discover that m7G-related lncRNAs play a vital role in the tumour immune microenvironment of gastric cancer, and a risk prediction model was established to identify patients with potential benefits from immunotherapy and predict the prognosis of GC patients.

Exhausted T cells hijacking the cancer-immunity cycle: Assets and liabilities

T cell exhaustion is an alternative differentiation path of T cells, sometimes described as a dysfunction. During the last decade, insights of T cell exhaustion acting as a bottle neck in the field of cancer immunotherapy have undoubtedly provoked attention. One of the main drivers of T cell exhaustion is prolonged antigen presentation, a prerequisite in the cancer-immunity cycle. The umbrella term "T cell exhaustion" comprises various stages of T cell functionalities, describing the dynamic, one-way exhaustion process. Together these qualities of T cells at the exhaustion continuum can enable tumor clearance, but if the exhaustion acquired timeframe is exceeded, tumor cells have increased possibilities of escaping immune system surveillance. This could be considered a tipping point where exhausted T cells switch from an asset to a liability. In this review, the contrary role of exhausted T cells is discussed.

Parallel single-cell and bulk transcriptome analyses reveal key features of the gastric tumor microenvironment

BACKGROUND

The tumor microenvironment (TME) has been shown to strongly influence treatment outcome for cancer patients in various indications and to influence the overall survival. However, the cells forming the TME in gastric cancer have not been extensively characterized.

RESULTS

We combine bulk and single-cell RNA sequencing from tumors and matched normal tissue of 24 treatment-naïve GC patients to better understand which cell types and transcriptional programs are associated with malignant transformation of the stomach. Clustering 96,623 cells of non-epithelial origin reveals 81 well-defined TME cell types. We find that activated fibroblasts and endothelial cells are most prominently overrepresented in tumors. Intercellular network reconstruction and survival analysis of an independent cohort imply the importance of these cell types together with immunosuppressive myeloid cell subsets and regulatory T cells in establishing an immunosuppressive microenvironment that correlates with worsened prognosis and lack of response in anti-PD1-treated patients. In contrast, we find a subset of IFNγ activated T cells and HLA-II expressing macrophages that are linked to treatment response and increased overall survival.

CONCLUSIONS

Our gastric cancer single-cell TME compendium together with the matched bulk transcriptome data provides a unique resource for the identification of new potential biomarkers for patient stratification. This study helps further to elucidate the mechanism of gastric cancer and provides insights for therapy.

The depths of PD-1 function within the tumor microenvironment beyond CD8+ T cells

Programmed cell death-1 (PD-1; CD279) is a cell surface receptor that is expressed in both innate and adaptive immune cells. The role of PD-1 in adaptive immune cells, specifically in CD8+ T cells, has been thoroughly investigated but its significance in other immune cells is yet to be well established. This review will address the role of PD-1 based therapies in enhancing non-CD8+ T cell immune responses within cancer. Specifically, the expression and function of PD-1 in non-CD8+ immune cell compartments such as CD4+ T helper cell subsets, myeloid cells and innate lymphoid cells (ILCs) will be discussed. By understanding the immune cell specific function of PD-1 within tissue resident innate and adaptive immune cells, it will be possible to stratify patients for PD-1 based therapies for both immunogeneic and non-immunogeneic neoplastic disorders. With this knowledge from fundamental and translational studies, PD-1 based therapies can be utilized to enhance T cell independent immune responses in cancers.

A novel cell senescence-related IncRNA survival model associated with the tumor immune environment in colorectal cancer

Long noncoding RNAs have a major role in tumorigenesis, development, and metastasis in colorectal cancer (CRC), participate in the regulation of cell senescence and are related to the prognosis of CRC. Therefore, it is important to validate cell senescence-related lncRNAs that correlate with prognosis in CRC.

Liposomal β-Sitosterol Suppresses Metastasis of CT26/luc Colon Carcinoma via Inhibition of MMP-9 and Evoke of Immune System

β-sitosterol (SITO) has been reported with anticancer effects; however, with poor bioavailability. The current study aimed to investigate whether liposomal encapsulated β-sitosterol (LS) has a better inhibition effect on tumor metastasis than β-sitosterol in a CT26/luc lung metastasis mouse model and the possible underlying mechanism. LS was liposomal-encapsulated SITO and was delivered to mice by oral gavage. The cell viability was determined by the MTT assay, and invasiveness of the tumor cells and related protein expression were evaluated with the invasion assay and Western blotting. For therapeutic efficacy evaluation, male BALB/c mice were treated with PBS, SITO, and LS once a day for 7 days prior to intravenous injections of CT26/luc cells; treatments were continued twice a week post-cell inoculation throughout the entire experiment. Tumor growth inhibition was monitored by bioluminescent imaging (BLI). IL-12, IL-18, and IFN-γ in the intestinal epithelium were determined by ELISA. The results show that LS treatment had a better invasion inhibition with lower cytotoxicity than SITO when the same dose was utilized. Notably, mice treated with LS significantly exhibited fewer metastases to the lungs and other tissues/organs compared with the Control and SITO groups. Additionally, the IL-12, IL-18, and IFN-γ levels were significantly increased in the LS-treated mice compared with the Control and SITO groups. The underlying mechanism may be through the inhibition of MMP-9 and elicitation of the antitumoral Th1 immune response, such as increasing CD4⁺ and CD8⁺ T cells, IL-12, IL-18, and IFN-γ.

microRNA-128-3p inhibits CD4+ regulatory T cells enrichment by targeting interleukin 16 in gastric cancer

Previous studies have confirmed that microRNA (miR)-128-3p is expressed at low levels in gastric cancer (GC), and low miR-128-3p expression promotes the growth of GC cells. However, whether the dysregulation of miR-128-3p expression affects tumor-infiltrating lymphocytes (TILs) and leads to immune escape remains unclear. In the present study, predictive bioinformatics approaches showed that miR-128-3p expression was inversely correlated with tumor-infiltrating lymphocyte enrichment. When CD4 + T cells and regulatory T cells (Tregs) were enriched, lower miR-128-3p expression was associated with worse overall survival. However, when numbers of CD8 + T cells were decreased, the upregulation of miR-128-3p expression had a favorable effect on GC prognosis. Dual-luciferase reporter assays and cell biology experiments revealed that interleukin 16 (IL16) was the target of miR-128-3p and was negatively regulated by miR-128-3p. In addition, GC cells were cocultured with T lymphocytes, and the subsequent flow cytometric analysis showed that overexpression of miR-128-3p in tumor cells decreased the percentages of CD4+ CD25+ Foxp3+ Tregs by downregulating IL16 expression in GC, whereas miR-128-3p inhibition had the opposite effect. Moreover, the recombinant IL16 reversed the effects of miR-128-3p overexpression, and a competitive antibody against the IL16 receptor CD4 also reversed the effects of miR-128-3p knockdown. These studies identified the mechanism by which the miR-128-3p/IL16 axis promotes the infiltration of CD4+ Tregs in GC, and this mechanism will be a promising therapeutic target in GC immunotherapy.

LncRNAs Target Ferroptosis-Related Genes and Impair Activation of CD4+ T Cell in Gastric Cancer

Gastric cancer (GC) is a malignant disease of the digestive tract and a life-threatening disease worldwide. Ferroptosis, an iron-dependent cell death caused by lipid peroxidation, is reported to be highly correlated with gastric tumorigenesis and immune cell activity. However, the underlying relationship between ferroptosis and the tumor microenvironment in GC and potential intervention strategies have not been unveiled. In this study, we profiled the transcriptome and prognosis data of ferroptosis-related genes (FRGs) in GC samples of the TCGA-STAD dataset. The infiltrating immune cells in GC were estimated using the CIBERSORT and XCELL algorithms. We found that the high expression of the hub FRGs (MYB, PSAT1, TP53, and LONP1) was positively correlated with poor overall survival in GC patients. The results were validated in an external GC cohort (GSE62254). Further immune cell infiltration analysis revealed that CD4⁺ T cells were the major infiltrated cells in the tumor microenvironment of GC. Moreover, the hub FRGs were significantly positively correlated with activated CD4⁺ T cell infiltration, especially Th cells. The gene features in the high-FRG score group were enriched in cell division, DNA repair, protein folding, T cell receptor, Wnt and NIK/NF-kappaB signaling pathways, indicating that the hub FRGs may mediate CD4⁺ T cell activation by these pathways. In addition, an upstream transcriptional regulation network of the hub FRGs by lncRNAs was also developed. Three lncRNAs (A2M-AS1, C2orf27A, and ZNF667-AS1) were identified to be related to the expression of the hub FRGs. Collectively, these results showed that lncRNA A2M-AS1, C2orf27A, and ZNF667-AS1 may target the hub FRGs and impair CD4⁺ T cell activation, which finally leads to poor prognosis of GC. Effective interventions for the above lncRNAs and the hub FRGs can help promote CD4⁺ T cell activation in GC patients and improve the efficacy of immunotherapy. These findings provide a novel idea of GC immunotherapy and hold promise for future clinical application.

CD4 T-Cell Exhaustion: Does It Exist and What Are Its Roles in Cancer?

In chronic infections and in cancer, persistent antigen stimulation under suboptimal conditions can lead to the induction of T-cell exhaustion. Exhausted T cells are characterized by an increased expression of inhibitory markers and a progressive and hierarchical loss of function. Although cancer-induced exhaustion in CD8 T cells has been well-characterized and identified as a therapeutic target (i.e., via checkpoint inhibition), in-depth analyses of exhaustion in other immune cell types, including CD4 T cells, is wanting. While perhaps attributable to the contextual discovery of exhaustion amidst chronic viral infection, the lack of thorough inquiry into CD4 T-cell exhaustion is particularly surprising given their important role in orchestrating immune responses through T-helper and direct cytotoxic functions. Current work suggests that CD4 T-cell exhaustion may indeed be prevalent, and as CD4 T cells have been implicated in various disease pathologies, such exhaustion is likely to be clinically relevant. Defining phenotypic exhaustion in the various CD4 T-cell subsets and how it influences immune responses and disease severity will be crucial to understanding collective immune dysfunction in a variety of pathologies. In this review, we will discuss mechanistic and clinical evidence for CD4 T-cell exhaustion in cancer. Further insight into the derivation and manifestation of exhaustive processes in CD4 T cells could reveal novel therapeutic targets to abrogate CD4 T-cell exhaustion in cancer and induce a robust antitumor immune response.

TIGIT Induces (CD3+) T Cell Dysfunction in Colorectal Cancer by Inhibiting Glucose Metabolism

T-cell immunoglobulin and immunoreceptor tyrosine-based inhibitory motif domain (TIGIT) is an immunosuppressive receptor expressed on the surface of immune cells, suppressing immune responses by activating the intracellular negative regulatory signals. TIGIT plays an important role in the pathogenesis of various tumors, but its immune escape in colorectal cancer remains unclear. We found that the proportion of CD3+TIGIT+ T cells was increased in peripheral blood and cancer tissue in colorectal cancer patients when compared with the healthy donors. These cells exhibited functional defects, low proliferative activity, impaired cytokine production and reduced glucose metabolism. A strong association was also observed between the elevated TIGIT expression and poor prognosis in this cohort. In the in vitro co-culture assays of T cells and tumor cells, the suppressed glucose metabolic activity of T cells was reversed by TIGIT blockade. In addition, this blockade induced the apoptosis and reduced G2/M transit in tumor cells. The antitumor efficacy of TIGIT Ab therapy was further demonstrated in a human colorectal xenograft mice model while co-blockers of TIGIT and PD-1 exhibited synergistic suppressing effects on tumor growth. These results suggest that while TIGIT induces CD3+ T cell dysfunction in colorectal cancer, co-targeting TIGIT and PD-1 can lead to an effective antitumor response and may serve as a novel therapeutic strategy for colorectal patients.

Immunophenotype of Gastric Tumors Unveils a Pleiotropic Role of Regulatory T Cells in Tumor Development

Gastric cancer (GC) patients display increased regulatory T cell (Tregs) numbers in peripheral blood and among tumor-infiltrating lymphocytes. Nevertheless, the role of Tregs in GC progression remains controversial. Here, we sought to explore the impact of Tregs in GCs with distinct histology, and whether Tregs can directly influence tumor cell behavior and GC development. We performed a comprehensive immunophenotyping of 82 human GC cases, through an integrated analysis of multispectral immunofluorescence detection of T cells markers and patient clinicopathological data. Moreover, we developed 3D in vitro co-cultures with Tregs and tumor cells that were followed by high-throughput and light-sheet imaging, and their biological features studied with conventional/imaging flow cytometry and Western blotting. We showed that Tregs located at the tumor nest were frequent in intestinal-type GCs but did not associate with increased levels of effector T cells. Our in vitro results suggested that Tregs preferentially infiltrated intestinal-type GC spheroids, induced the expression of IL2Rα and activation of MAPK signaling pathway in tumor cells, and promoted spheroid growth. Accumulation of Tregs in intestinal-type GCs was increased at early stages of the stomach wall invasion and in the absence of vascular and perineural invasion. In this study, we proposed a non-immunosuppressive mechanism through which Tregs might directly modulate GC cells and thereby promote tumor growth. Our findings hold insightful implications for therapeutic strategies targeting intestinal-type GCs and other tumors with similar immune context.

Persistent anti-NY-ESO-1-specific T cells and expression of differential biomarkers in a patient with metastatic gastric cancer benefiting from combined radioimmunotherapy treatment: a case report

Combined radioimmunotherapy is currently being investigated to treat patients with cancer. Anti-programmed cell death-1 (PD-1) immunotherapy offers the prospect of long-term disease control in solid tumors. Radiotherapy has the ability to promote immunogenic cell death leading to the release of tumor antigens, increasing infiltration and activation of T cells. New York esophageal squamous cell carcinoma-1 (NY-ESO-1) is a cancer-testis antigen expressed in 20% of advanced gastric cancers and known to induce humoral and cellular immune responses in patients with cancer. We report on the dynamic immune response to the NY-ESO-1 antigen and important immune-related biomarkers in a patient with metastatic gastric cancer treated with radiotherapy combined with anti-PD-1 pembrolizumab antibody.Our patient was an 81-year-old man diagnosed with locally advanced unresectable mismatch repair-deficient gastric cancer having progressed to a metastatic state under a second line of systemic treatment consisting of an anti-PD-1 pembrolizumab antibody. The patient was subsequently treated with local radiotherapy administered concomitantly with anti-PD-1, with a complete response on follow-up radiologic assessment. Disease control was sustained with no further therapy for a period of 12 months before relapse. We have identified an NY-ESO-1-specific interferon-γ (IFN-γ) secretion from the patients' T cells that was significantly increased at response (****p˂0.0001). A novel promiscuous immunogenic NY-ESO-1 peptide P39 (P_153-167) restricted to the four patient's HLA-DQ and HLA-DP alleles was identified. Interestingly, this peptide contained the known NY-ESO-1-derived HLA-A2-02:01(P_157-165) immunogenic epitope. We have also identified a CD107⁺ cytotoxic T cell subset within a specific CD8⁺/HLA-A2-NY-ESO-1 T cell population that was low at disease progression, markedly increased at disease resolution and significantly decreased again at disease re-progression. Finally, we identified two groups of cytokines/chemokines. Group 1 contains five cytokines (IFN-γ, tumor necrosis factor-α, interleukin-2 (IL-2), IL-5 and IL-6) that were present at disease progression, significantly downregulated at disease resolution and dramatically upregulated again at disease re-progression. Group 2 contains four biomarkers (perforin, soluble FAS, macrophage inflammatory protein-3α and C-X-C motif chemokine 11/Interferon-inducible T Cell Alpha Chemoattractant that were present at disease progression, significantly upregulated at disease resolution and dramatically downregulated again at disease re-progression. Combined radioimmunotherapy can enhance specific T cell responses to the NY-ESO-1 antigen that correlates with beneficial clinical outcome of the patient.

Systematic profiling of alternative splicing in Helicobacter pylori-negative gastric cancer and their clinical significance

Background

Alternative splicing (AS) may cause structural and functional variations in the protein to promote the proliferation of tumor cells. However, there is no comprehensive analysis of the clinical significance of AS in Helicobacter pylori-negative gastric cancer (HP⁻ GC).

Methods

The clinical, gene expression profile data and AS events of 138 HP⁻ GC patients were obtained from the database named the cancer genome atlas. Differently expressed AS (DEAS) events were determined by a comparison of the PSI values between HP⁻ GC samples and adjacent normal samples. Unsupervised clustering analysis, proportional regression and Kaplan–Meier analysis were used to explore the association between clinical data and immune features and to establish two nomograms about the prognosis of HP⁻ GC. Finally, splicing networks were constructed using Cytoscape.

Results

A total of 48141 AS events and 1041 DEAS events were found in HP⁻ GC. Various functions and pathways of DEAS events parent genes were enriched, such as cell-substrate junction, cell leading edge, focal adhension, and AMPK signaling. Seven overall survival (OS)-related and seven disease-free survival (DFS)-related AS events were used to construct the prognostic signatures. Based on the independent prognostic factors, two nomograms were established and showed excellent performance. Then, splicing regulatory networks among the correlations suggested that splicing factors were significantly associated with prognostic DEASs. Finally, the unsupervised clustering analysis revealed that DEAS-based clusters were associated with clinical characteristics, tumor microenvironment, tumor mutation burden, and immune features.

Conclusion

Seven OS-related and seven DFS-related AS events have been found to be correlated with the prognosis of HP⁻ GC and can be used as prognostic factors to establish an effective nomogram.

The Immune Microenvironment Impacts Survival in Western Patients with Gastric Adenocarcinoma

BACKGROUND

Expression of CD3+ T cells, CD8+ cytotoxic T cells, CD45RO+ memory T cells, and FOXP3+ regulatory T cells at the invasive margin (IM) and tumor center (TC) has correlated with survival in gastric adenocarcinoma (GA) patients from East Asia, independent of anatomic staging. The reason for improved survival in East Asians compared with Western patients is a subject of debate. This study examined the immune profiles of a cohort of Western patients with GA, and their association with overall survival (OS).

METHODS

Immunohistochemistry (IHC) using antibodies to CD3, CD4, CD8, CD45RO, and FOXP3 was performed on a randomly selected resected GA specimens from 88 Western patients. Cutoffs for high or low expression of each marker were determined with maximally selected rank statistics, and multivariable Cox proportional-hazards models constructed to evaluate the relationship between OS and expression of each marker at the IM and TC.

RESULTS

Immune cell density was independent of anatomic staging. High expression of CD3, CD4, CD8, and CD45RO at the IM along with CD4 and FOXP3 at the TC were associated with improved OS. A combined marker of CD3, CD8, CD45RO, and FOXP3 associated with OS in East Asian GA was also validated.

DISCUSSION

This is the first report in US patients to demonstrate that high expression of multiple subsets of T lymphocytes in GA is associated with better OS independent of clinical factors and anatomic stage. Further evaluation of immune-modulating mechanisms may explain survival differences between Western and Eastern patients and provide opportunity for novel treatments.

S-15 in combination of Akt inhibitor promotes the expansion of CD45RA-CCR7+ tumor infiltrating lymphocytes with high cytotoxic potential and downregulating PD-1+Tim-3+ cells as well as regulatory T cells

Background

Autologous tumor-infiltrating lymphocytes (Tils) immunotherapy is a promising treatment in patients with advanced hepatocellular cancer. Although Tils treatment has shown great promise, their persistence and the efficacy after adoptive-transfer are insufficient and remain a challenge. Studies have demonstrated that IL-15 and Akt inhibitor can regulate T cell differentiation and memory. Here, we constructed S-15 (Super human IL-15), a fusion protein consisting of human IL-15, the sushi domain of the IL-15 receptor α chain and human IgG-Fc. Herein we compared the effects of S-15 with IL-2 or in combination with Akti on the expansion and activation of Tils.

Methods

Hepatocellular cancer tissues were obtained from 6 patients, Tils were expanded using IL-2, IL-2/S-15, IL-2/Akti or in combination IL-2/S-15/Akti. At day 10, anti-CD3 antibody was added to the culture media and expanded to day 25. The composition, exhaustion and T-cell differentiation markers (CD45RA/CCR7) were analyzed by flow cytometry.

Results

We found that IL-2/S-15/Akti expanded Tils and showed the highest percentage of central memory CD45RA^-CCR7⁺ phenotype prior to anti-CD3 antibody activation and after anti-CD3 antibody activation. T cells cultured with IL-2/S-15/Akti exhibited a mixture of CD4⁺, CD8⁺, and CD3⁺CD4^-CD8^- T cells; S-15 in combination with Akt inhibitor downregulated the expression of PD-1⁺Tim-3⁺ on Tils and decreased the Tregs in Tils. Additionally, the Tils expanded in the presence of the Akt inhibitor and S-15 showed enhanced antitumor activity as indicated by the increase in IFN-γ producing tumor infiltrating CD8⁺ T cells and without comprising the Tils expansion.

Conclusion

Our study elucidates that IL-2/S-15/Akti expanded Tils and represent a viable source for the cellular therapy for patients with hepatocellular cancer.

Function of fibroblast growth factor 2 in gastric cancer occurrence and prognosis

The present study aimed to explore the role of fibroblast growth factor 2 (FGF2) in the development and prognosis of gastric cancer (GC). The relationship between FGF2 mRNA expression levels and the clinical characteristics of GC was investigated using microarray data from four GC cohorts involving 726 patients obtained from the Gene Expression Omnibus. The results of the present study indicated that FGF2 expression levels were an independent factor affecting the prognosis of GC. The primary functions of FGF2 were related to cell adhesion and angiogenesis, and patients with high levels of FGF2 expression had poorer TNM staging and prognosis; these differences were statistically significant. In terms of immune infiltration, a higher extent of M2 macrophage intrusion was observed in patients with higher levels of FGF2. However, the degree of infiltration by dendritic and CD4⁺ T cells was lower, and this difference was statistically significant. Multivariate Cox proportional hazards model analysis revealed that age, TNM staging and FGF2 expression levels were independent prognostic factors for GC. In summary, FGF2 expression was demonstrated to be an independent prognostic factor in GC, and higher levels of FGF2 may promote the progression of this malignancy.

Gastric Cancer in the Era of Immune Checkpoint Blockade

Gastric cancer (GC) is one of the most important malignancies worldwide because of its high incidence and mortality. The very low survival rates are mainly related to late diagnosis and limited treatment options. GC is the final clinical outcome of a stepwise process that starts with a chronic and sustained inflammatory reaction mounted in response to Helicobacter pylori infection. The bacterium modulates innate and adaptive immunity presumably as part of the strategies to survive, which favors the creation of an immunosuppressive microenvironment that ultimately facilitates GC progression. T-cell exhaustion, which is characterized by elevated expression of immune checkpoint (IC) proteins, is one of the most salient manifestations of immunosuppressive microenvironments. It has been consistently demonstrated that the tumor-immune microenvironment(TIME)‐exhausted phenotype can be reverted by blocking ICs with monoclonal antibodies. Although these therapies are associated with long-lasting response rates, only a subset of patients derive clinical benefit, which varies according to tumor site. The search for biomarkers to predict the response to IC inhibition is a matter of intense investigation as this may contribute to maximize disease control, reduce side effects, and minimize cost. The approval of pembrolizumab for its use in GC has rocketed immuno-oncology research in this cancer type. In this review, we summarize the current knowledge centered around the immune contexture and recent findings in connection with IC inhibition in GC.

Induction/reversal of drug resistance in gastric cancer by non-coding RNAs (Review)

Gastric cancer (GC) is one of the most prevalent and malignant types of cancer worldwide. In China, it is the second most common type of cancer and the malignancy with the highest incidence and mortality rate. Chemotherapy for GC is not always effective due to the development of drug resistance. Drug resistance, which is frequently observed in GC, undermines the success rate of chemotherapy and the survival of patients with GC. The dysregulation of non‑coding RNAs (ncRNAs), primarily microRNAs (miRNAs or miRs) and long non‑coding RNAs (lncRNAs), is involved in the development of GC drug resistance via numerous mechanisms. These mechanisms contribute to the involvement of a large and complex network of ncRNAs in drug resistance. In this review, we focus on and summarize the latest research on the specific mechanisms of action of miRNAs and lncRNAs that modulate drug resistance in GC. In addition, we discuss future prospects and clinical applications of ncRNAs as potential targeted therapies against the chemoresistance of GC.

The Therapeutic Strategies of Regulatory T Cells in Malignancies and Stem Cell Transplantations

Regulatory T cells (Treg cells) are considered one of the main dynamic cell types within the immune system. Because Treg cells suppress immune responses, they have potential roles in immunological self-tolerance and may help to maintain immune homeostasis. Promoting Treg cell function and increasing their numbers might be useful in treating autoimmune disorders, as well as preventing allograft rejection. However, studies of mice and humans demonstrate that Treg cells promote cancer progression and suppress antitumor immunity. Therefore, suppressing Treg cell function or reducing their numbers could support the immune system's response to pathogenic microorganisms and tumors. As a result, there is great interest in investigating the Treg cells role in the treatment of hematological and nonhematological malignancies. Consequently, Treg cells could be a fundamentally important target for pathologies of the immune system. Targeting effector Treg cells could help to distinguish and selectively decrease these cells while preserving other Treg cells needed to suppress autoimmunity. Currently, a promising way to treat malignancies and other autoimmune disorders is stem cell transplantation. Stem cell transplants (SCT) can help to manage the production of Treg cells and also may produce more efficient Treg cells, thereby suppressing clinical disease progression. Specifically, mature T cells within the engrafted stem cells mediate this SCT beneficial effect. During SCT, the recipient's immune system is replaced with a donor, which allows for improved immune system function. In addition, SCT can protect from disease relapse, as graft-versus-host disease (GvHD) in transplant patients can be protective against cancer recurrence. The current review will define the role of regulatory T cells in treatment of malignancy. Additionally, it will summarize current promising research regarding the utility of regulatory T cells in stem cell transplantation.

The effects of Tim-3 activation on T-cells in gastric cancer progression

The incidence of gastric cancer is high, especially in China. The present study aims to provide a novel therapeutic target for gastric cancer. Peripheral blood, cancerous and paracancerous tissues were collected from patients with gastric cancer. T-cell immunoglobulin mucin domain-3 (Tim-3) expression in T-cells was measured and the correlation between Tim-3 expression and the T staging of gastric cancer was analyzed. The levels of T-cell secreted interferon (IFN)-γ and tumor necrosis factor (TNF)-α were assessed following Tim-3 signaling pathway activation. A nude mouse model of gastric cancer was established and Tim-3-stimulated T-cells were injected into the mice to evaluate tumor growth. The results of the present study demonstrated that Tim-3 expression levels from the paracancerous and cancerous gastric tissues were significantly increased compared with the peripheral blood, while its expression was significantly increased in cancerous compared with paracancerous gastric tissues. With the T staging of gastric cancer increasing, the expression of Tim-3 gradually increased. The activation of the Tim-3 signaling pathway in T-cells may inhibit IFN-γ and TNF-α secretion, and the results from the nude mice tumor model demonstrated that the inhibitory effect on tumor growth by T-cells was reduced by Tim-3 signaling pathway activation. The expression level of Tim-3 on the surface of tumor infiltrating T-cells in gastric cancer tissue increases significantly and the increased Tim-3 signaling may inhibit the function of T-cells. The results suggest that the increased expression of Tim-3 on T-cells may be involved the development of gastric cancer.

Prognostic significance of tumor immune microenvironment and immunotherapy: Novel insights and future perspectives in gastric cancer

Despite a decrease in gastric cancer incidence, the development of novel biologic agents and combined therapeutic strategies, the prognosis of gastric cancer remains poor. Recently, the introduction of modern immunotherapy, especially using immune checkpoint inhibitors, led to an improved prognosis in many cancers. The use of immunotherapy was also associated with manageable adverse event profiles and promising results in the treatment of patients with gastric cancer, especially in heavily pretreated patients. These data have led to an accelerated approval of some checkpoint inhibitors in this setting. Understanding the complex relationship between the host immune microenvironment and tumor and the immune escape phenomenon leading to cancer occurrence and progression will subsequently lead to the identification of prognostic immune markers. Furthermore, this understanding will result in the discovery of both new mechanisms for blocking tumor immunosuppressive signals and pathways to stimulate the local immune response by targeting and modulating different subsets of immune cells. Due to the molecular heterogeneity of gastric cancers associated with different clinico-biologic parameters, immune markers expression and prognosis, novel immunotherapy algorithms should be personalized and addressed to selected subsets of gastric tumors, which have been proven to elicit the best clinical responses. Future perspectives in the treatment of gastric cancer include tailored dual immunotherapies or a combination of immunotherapy with other targeted agents with synergistic antitumor effects.