CAF-macrophage crosstalk in tumour microenvironments governs the response to immune checkpoint blockade in gastric cancer peritoneal metastases

Targeting myeloid cells with platelet-derived extracellular vesicles to overcome resistance of immune checkpoint blockade therapy

Immune checkpoint blockade (ICB) therapy is designed to boost antitumor immune responses, yet it may unintentionally alter the chemokine profile, which can attract suppressive myeloid cells to the tumor, leading to acquired immune resistance. To address this, we developed a platform that targets myeloid cells post-ICB therapy using platelet-derived extracellular vesicles (PEVs). Unlike free drug administration, this system selectively targets anti-PD-L1-treated tumors through the CXCL-CXCR2 axis, effectively redirecting myeloid cells and overcoming ICB resistance. Consequently, mice exhibited robust responses to subsequent ICB therapy cycles, resulting in significantly enhanced tumor clearance and prolonged survival. The PEVs' targeting capability was also effective in tumors treated with chemotherapy and radiotherapy, suggesting a wide range of potential applications. In summary, PEVs offer a versatile platform for targeted immunomodulation to counteract acquired immune resistance during ICB therapy.

Tumor immune microenvironment remodeling after neoadjuvant therapy in gastric cancer: Update and new challenges

Gastric cancer (GC) is a malignant tumor with one of the highest morbidity and death rates in the world. Neoadjuvant therapy, including neoadjuvant chemotherapy (NAC) and NAC combined with immunotherapy, can improve the resection and long-term survival rates. However, not all patients respond well to neoadjuvant therapy. It has been confirmed that immune cells in the tumor immune microenvironment, including T cells, B cells, and natural killer cells, can affect the efficacy of neoadjuvant therapy. This paper summarizes current preclinical and clinical evidence to more fully describe the effects of neoadjuvant therapy on the immune microenvironment of GC, to provide the impetus to identify biomarkers to predict the potency of neoadjuvant therapy, and to identify the mechanisms of drug resistance, which should promote the development of individualized and accurate treatments for GC patients.

Overcoming the novel glycan-lectin checkpoints in tumor microenvironments for the success of the cross-presentation-based immunotherapy

In pursuit of meeting the ever-rising demand for cancer therapies, cross-presentation-based glyconanovaccines (GNVs) targeting C-type lectin receptors (CLRs) on DCs have shown significant potential as cutting-edge cancer immunotherapy. GNVs are an attractive approach to induce anti-cancer cytotoxic T lymphocyte responses. Despite immune checkpoints (ICs) being well established and an obstacle to the success of GNVs, glycan-lectin circuits are emerging as unique checkpoints due to their immunomodulatory functions. Given the role of aberrant tumor glycosylation in promoting immune evasion, mitigating these effects is crucial for the efficacy of GNVs. Lectins, such as siglecs and galectins, are detrimental to the tumor immune landscape as they promote an immunosuppressive TME. From this perspective, this review aims to explore glycan-lectin ICs and their influence on the efficacy of GNVs. We aim to discuss various ICs in the TME followed by drawbacks of immune checkpoint inhibitors (ICIs). We will also emphasize the altered glycosylation profile of tumors, addressing their immunosuppressive nature along with ways in which CLRs, siglecs, and galectins contribute to immune evasion and cancer progression. Considering the resistance towards ICIs, current and prospective approaches for targeting glycan-lectin circuits and future prospects of these endeavors in harnessing the full potential of GNVs will also be highlighted.

Integrative Analysis of EPHX4 as a Novel Prognostic and Diagnostic Biomarker in Lung Adenocarcinoma

Lung adenocarcinoma (LUAD) remains a leading cause of cancer-related mortality, necessitating the identification of novel biomarkers for improved prognosis and diagnosis. This study investigates the role of epoxide hydrolase 4 (EPHX4), a member of the epoxide hydrolase family, in LUAD. Using data sourced from The Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression (GTEx) databases, which were subsequently validated by the Gene Expression Omnibus (GEO), we analyzed levels of EPHX4 expression, mutation, and methylation in tumors versus normal tissues. Our findings revealed a significant upregulation of EPHX4 in LUAD tissues compared to normal lung tissues (p < 0.001), correlating with poorer overall survival (OS), disease-specific survival (DSS), and progression-free interval (PFI). Furthermore, EPHX4 exhibited considerable diagnostic potential, as demonstrated by an area under the curve (AUC) of 0.854 in a Receiver Operating Characteristic (ROC) analysis. Notably, EPHX4 expression was associated with immune infiltration, specifically Th2 cells, neutrophils, and macrophages, along with immune checkpoint molecules including PD-L1, PD-L2, and TIM-3. Additionally, EPHX4 was involved in pivotal tumor-associated pathways, particularly cell cycle regulation. In conclusion, an elevated EPHX4 expression is indicative of poorer prognosis in LUAD and may play a role in immune evasion and cell cycle dysregulation, highlighting its potential as a promising biomarker for the diagnosis and prognostic prediction of LUAD.

Activated Immune and Complement C3 Are Potential Contributors in MASH via Stimulating Neutrophil Extracellular Traps

The number of metabolic dysfunction-associated steatotic liver disease (MASLD) patients is increasing rapidly. More attention has been paid to the relationship between immunity and MASLD. This study explored the roles of serum autoantibodies, immunoglobulins, and complements in MASLD. A total of 182 MASLD patients were investigated and grouped by autoantibody or NAS scores. Correlation between immunology and clinical features was assessed. In addition, metabolic dysfunction-associated steatohepatitis (MASH) models were constructed to verify the findings. Neutrophils were isolated from mice and treated with complement C3 to investigate the association between C3 and neutrophil extracellular traps (NETs). IgG, IgM, and NAS scores in the autoantibody positive group were significantly higher than those in the autoantibody negative group. Antinuclear antibodies (ANA), IgA, IgE, IgG, C3, C4, ALT, and AST were related to MASH. Meanwhile, IgA and C3 correlated with the severity of MASLD. The ROC curve showed that IgA > 2.990 g/L or C3 > 1.115 g/L predicted the presence of MASH. More importantly, IgG, activated C3, and NETs were increased in MASH. C3 stimulation directly induced NET formation in the neutrophils. Immunity systems were activated in MASH and elevated IgG activated C3 to stimulate the production of NETs, thus exacerbating MASH.

Targeting PTBP3-Mediated Alternative Splicing of COX11 Induces Cuproptosis for Inhibiting Gastric Cancer Peritoneal Metastasis

Numerous aberrant splicing events are implicated in tumor progression, yet comprehensive reports on splicing factors and events associated with peritoneal metastasis in gastric cancer (GCPM) are lacking. In this study, PTBP3 is found to be significantly overexpressed in peritoneal metastatic tissues of gastric cancer compared to primary tumor tissues, and higher PTBP3 expression correlates with poorer prognosis. Using gastric cancer cells and patient-derived organoids (PDO), the role of PTBP3 in promoting tumor invasion and proliferation is investigated. Mechanistically, through full-length transcriptome sequencing, PTBP3 mediates exon 4 skipping in its target gene COX11, leading to shorter transcripts that impair COX11 protein function, reducing mitochondrial copper content and enabling tumor cells to evade cuproptosis. Antisense oligonucleotide (ASO) drugs targeting the short COX11 transcripts effectively degrade mRNA, disrupting copper homeostasis. In PDO-based xenograft models, exogenous copper ionophores combined with ASO drugs induce excessive copper accumulation in mitochondria, triggering proteotoxic stress and cuproptosis. Overall, PTBP3-mediated exon 4 skipping in COX11 pre-mRNA is critical for tumor cell survival and progression in GCPM, offering potential therapeutic strategies targeting copper metabolism.

PD-1 involvement in CD8+ tumor-infiltrating lymphocytes in patients with colonic-derived peritoneal adenocarcinoma

Immune checkpoint blockade with anti-programmed cell death protein 1 (PD-1) antibody has become a hot topic for the treatment of human malignancies. Here, we aimed to investigate whether the percentage of PD-1 in CD8+ tumor-infiltrating lymphocytes correlates with the progression of colonic-derived peritoneal adenocarcinoma (PA). Peripheral blood and tissue samples from 40 patients with colonic-derived PA were collected and subjected to multicolor flow cytometry analysis of the percentage of peripheral PD-1+CD8+ T cells. The multiple immunofluorescence method was used to detect the positive percentages of PD-1 and CD8 in the tissues. The enrolled patients were divided into groups by recurrence interval (less than 6 months, greater than two years) and differentiation grade (low, well/moderate). In the colonic-derived PA tissues, the percentages of cells positive for PD-1, CD8, and PD-1+CD8+ were higher in the paracancer tissues compared with cancerous tissues. PD-1+CD8+ T cells had an increased presence in peripheral blood than in tissues. Our data also indicated that colonic-derived PA patients with less than a six-month recurrence interval presented higher levels of PD-1 in CD8+ tumor-infiltrating lymphocytes in than the two-year recurrence group. The level of PD-1+CD8+T cells in the tissue correlated with the clinical outcome of colonic-derived PA. Higher percentages of PD-1+CD8+T cells correlated with a shorter progression-free survival (PFS). PD-1 in CD8+ tumor-infiltrating lymphocytes may have a good predictive value for immunotherapy of colonic-derived PA and act as the prognostic factor for PFS.

Single-cell profiling uncovers the intricate pathological niche diversity in brain, lymph node, bone, and adrenal metastases of lung cancer

PURPOSE

The aim of this study is to explore the pathological niche of cancer metastasis and the site-specific interactions between tumor cells and the microenvironment, understand the mechanisms driving metastasis progression and identify potential therapeutic targets.

METHODS

Data from four lung cancer metastasis datasets (GSE123902, GSE131907, GSE148071, and GSE186344) were downloaded and subjected to stringent quality control and filtering. Cell types were identified using canonical markers, and pseudotime trajectory analysis was performed to evaluate cell differentiation. Functional and pathway enrichment analyses, including ssGSEA and GO/KEGG, were conducted. CellphoneDB was used to analyze intercellular communication, ranking receptor-ligand interactions based on communication strength.

RESULTS

Eleven cell types were identified after quality control, revealing significant heterogeneity and site-specific functionality in lung cancer metastases. CTLs showed notable activity in antigen presentation and T-cell differentiation pathways, with DNAJB1⁺ CTLs playing a dominant role in cytotoxicity and immune regulation. B cells, myeloid cells, and CAFs were involved in immune modulation, defense, and matrix remodeling through specific signaling pathways. Tumor cell subclusters drove proliferation, migration, and immune evasion via immune-regulatory, Hippo, and TGF-beta pathways. No overlapping pathways were observed across metastatic sites. Cell communication analysis identified PPIA-BSG and APP-CD74 as key axes in brain and lymph node metastases, while FN1-Integrin and CTLA4-CD86 dominated in bone and adrenal metastases, respectively.

CONCLUSIONS

In summary, this study highlights the functional heterogeneity and site-specific interactions of cells in lung cancer metastases, providing insights into the mechanisms shaping metastatic niches and potential therapeutic strategies.

Comprehensive Analyses of Single-Cell and Bulk RNA Sequencing Data From M2 Macrophages to Elucidate the Immune Prognostic Signature in Patients with Gastric Cancer Peritoneal Metastasis

Purpose

The peritoneum is a common site of metastasis in gastric cancer (GC), associated with poor prognosis and significant morbidity. The proclivity of GCs to metastasize to the peritoneum has been hypothesized to occur due the latter's immunosuppressive microenvironment, such as stromal infiltration and M2 macrophage enrichment, which are associated with increased risk of PM. As far as we know, a model that can effectively predict the prognosis of patients with GCPM is still lacking. Consequently, we constructed a prognostic risk model based on M2 macrophages associated with gastric cancer peritoneal metastasis, aiming to enhance predictive precision and guide tailored therapeutic interventions.

Methods

M2 macrophage-associated genes were identified in combination with marker genes from single-cell RNA sequencing (scRNA-seq) and modular genes from weighted gene coexpression network analysis (WGCNA). A prognostic model was constructed via LASSO analysis and validated in internal and external cohorts. We further compared the immune microenvironment, immune checkpoints, and chemotherapeutic drug sensitivity between patient groups stratified by risk to clarify the immune landscape in the GCPM.

Results

Our study identified 38 M2 macrophage-related genes via single-cell and bulk RNA sequencing. We developed a prognostic model based on the expression levels of 4 signature genes: DAB2, SPARC, PLTP, and FOLR2. The feasibility of the model was validated with internal and external validation sets (TCGA, GSE62254 and IMvigor210). The model also supported the prediction results of prognosis on the basis of the immunohistochemical results. Notably, patients with higher risk scores had a lower proportion of MSI-H and TMB, a higher prevalence of stages III-IV, and a lower likelihood of responding favorably to immunotherapy.

Conclusion

Our prognostic risk model could effectively predict the prognosis and response to chemo-immune therapy in patients with GCPM. The risk score is a promising independent prognostic factor that is closely correlated with the immune microenvironment and clinicopathological characteristics.

Cancer associated fibroblasts in cancer development and therapy

Cancer-associated fibroblasts (CAFs) are key players in cancer development and therapy, and they exhibit multifaceted roles in the tumor microenvironment (TME). From their diverse cellular origins, CAFs undergo phenotypic and functional transformation upon interacting with tumor cells and their presence can adversely influence treatment outcomes and the severity of the cancer. Emerging evidence from single-cell RNA sequencing (scRNA-seq) studies have highlighted the heterogeneity and plasticity of CAFs, with subtypes identifiable through distinct gene expression profiles and functional properties. CAFs influence cancer development through multiple mechanisms, including regulation of extracellular matrix (ECM) remodeling, direct promotion of tumor growth through provision of metabolic support, promoting epithelial-mesenchymal transition (EMT) to enhance cancer invasiveness and growth, as well as stimulating cancer stem cell properties within the tumor. Moreover, CAFs can induce an immunosuppressive TME and contribute to therapeutic resistance. In this review, we summarize the fundamental knowledge and recent advances regarding CAFs, focusing on their sophisticated roles in cancer development and potential as therapeutic targets. We discuss various strategies to target CAFs, including ECM modulation, direct elimination, interruption of CAF-TME crosstalk, and CAF normalization, as approaches to developing more effective treatments. An improved understanding of the complex interplay between CAFs and TME is crucial for developing new and effective targeted therapies for cancer.

FAP upregulates PD-L1 expression in cancer-associated fibroblasts to exacerbate T cells dysfunction and suppress anti-tumor immunity

FAP-positive cancer-associated fibroblasts (CAFs), recognized as a critical subset of CAFs, have been implicated in fostering an immunosuppressive tumor microenvironment in various cancers. However, their potential mechanisms of immunosuppression, particularly in modulating T cells, remain elusive. In this study, multiple internal cohorts consisting of 328 patients as well as 5 external cohorts were integrated to delineate the association between unfavorable prognosis or therapeutic resistance and FAP+ CAFs in gastric cancer patients. Subsequently, using in vivo mice models and in vitro co-culture system, we found that elevated infiltration levels of FAP+ CAF exacerbated immunosuppression in the tumor microenvironment by facilitating CD8+ T cells dysfunction. Mechanistically, FAP impeded the degradation of STAT1 protein in CAFs, thereby sustaining PD-L1 transcription and fostering T cell exhaustion. Treatment with PD-L1 neutralizing antibodies effectively attenuated FAP-mediated immunosuppression, restoring anti-tumor immunity of T cells. Overall, our findings underscore the vital role of FAP+ CAFs in directly suppressing T cell-mediated anti-tumor immunity via PD-L1 upregulation, paving the way for the development of FAP-targeted therapies in clinical settings.

Clinical significance of the tumor microenvironment on immune tolerance in gastric cancer

In the realm of oncology, the tumor microenvironment (TME)-comprising extracellular matrix components, immune cells, fibroblasts, and endothelial cells-plays a pivotal role in tumorigenesis, progression, and response to therapeutic interventions. Initially, the TME exhibits tumor-suppressive properties that can inhibit malignant transformation. However, as the tumor progresses, various factors induce immune tolerance, resulting in TME behaving in a state that promotes tumor growth and metastasis in later stages. This state of immunosuppression is crucial as it enables TME to change from a role of killing tumor cells to a role of promoting tumor progression. Gastric cancer is a common malignant tumor of the gastrointestinal tract with an alarmingly high mortality rate. While chemotherapy has historically been the cornerstone of treatment, its efficacy in prolonging survival remains limited. The emergence of immunotherapy has opened new therapeutic pathways, yet the challenge of immune tolerance driven by the gastric cancer microenvironment complicates these efforts. This review aims to elucidate the intricate role of the TME in mediating immune tolerance in gastric cancer and to spotlight innovative strategies and clinical trials designed to enhance the efficacy of immunotherapeutic approaches. By providing a comprehensive theoretical framework, this review seeks to advance the understanding and application of immunotherapy in the treatment of gastric cancer, ultimately contributing to improved patient outcomes.

OSBPL3 modulates the immunosuppressive microenvironment and predicts therapeutic outcomes in pancreatic cancer

BACKGROUND

Pancreatic cancer is characterized by a complex tumor microenvironment that hinders effective immunotherapy. Identifying key factors that regulate the immunosuppressive landscape is crucial for improving treatment strategies.

METHODS

We constructed a prognostic and risk assessment model for pancreatic cancer using 101 machine learning algorithms, identifying OSBPL3 as a key gene associated with disease progression and prognosis. We integrated multi-dataset analyses, single-cell transcriptomic data, and functional experiments to explore the role of OSBPL3 in pancreatic cancer.

RESULTS

Our risk prediction model, developed using machine learning algorithms, demonstrated high predictive accuracy across multiple datasets. Notably, the "rf" algorithm model showed an AUC of 1 in the training set and AUCs of 0.887 and 0.977 in two validation datasets. Ridge regression analysis identified OSBPL3 as a core prognostic feature gene. High OSBPL3 expression in pancreatic cancer samples was associated with immunosuppressive characteristics, including reduced CD8 + T cell infiltration and increased immunosuppressive cell populations such as Treg cells and M2 macrophages. Transcriptomic sequencing following OSBPL3 knockdown revealed enrichment of immune-related pathways, suggesting OSBPL3's influence on the immune microenvironment. Single-cell analyses further confirmed OSBPL3's role in shaping the immunosuppressive landscape by modulating Treg cells and M2 macrophages. Additionally, OSBPL3 expression was linked to resistance to immunotherapy, with high OSBPL3 expression associated with lower Immunophenoscore (IPS) scores, indicating poor responsiveness to immunotherapy.

CONCLUSIONS

Our study reveals OSBPL3 as a critical regulator of the immunosuppressive microenvironment in pancreatic cancer and a potential therapeutic target. Targeting OSBPL3 may enhance the efficacy of immunotherapy and improve patient outcomes. Further research is warranted to explore OSBPL3 as a biomarker for predicting immunotherapy response and as a potential therapeutic target in combination with anti-PD1 therapy.