Tissue-resident memory (TRM) T cells have emerged as key players in cancer immunosurveillance, and their presence has been linked to a favorable clinical outcome in solid cancer patients. Liver metastases exhibit a highly immunosuppressive tumor microenvironment, however, the role and clinical impact of TRM cell infiltration in colorectal cancer remain elusive. The expression of several tissue residency and activation biomarkers has been investigated on tumor-infiltrating lymphocytes isolated from 26 patients' colorectal cancer liver metastases (CRC liver metastases) and compared to 16 peripheral blood samples of patients with CRC liver metastases. Cytokine production was also evaluated in in vitro-activated TRM and non-TRM cells. The prognostic value of TRM cells was also assessed in a well-defined cohort of CRC liver metastases. Here we identified two subsets of TRM cells expressing CD103 and/or CD69 showing significantly higher expression of tissue residency and activation biomarkers. CD103+CD69+ TRM cells subset showed almost exclusive expression of tumor reactivity biomarkers PD-1 and CD39. Supporting this observation, CD103+CD69+ TRM cells showed a more oligoclonal TCR repertoire. Both TRM subsets presented higher cytotoxic and functional capacity compared to non-TRM cells. Our study shows that only the presence of CD103+CD69+ TRM cells is associated with longer recurrence-free survival of colorectal cancer patients with liver metastases. Taken together, our work demonstrates the existence of a phenotypic heterogeneity of TRM cells in colorectal cancer liver metastases. In this study, we identified a population of CD103+CD69+ TRM cells exhibiting the characteristics of tumor reactivity and correlated with better patients' prognosis, with potential implications in optimal therapeutic strategies determination.

Colorectal cancer (CRC) is a major global health burden, with immunotherapy often limited by immune tolerance and resistance. This study introduces an innovative approach using Selenium Nanoparticles-Loaded Extracellular Vesicles combined with Interleukin-32 and Engineered Probiotic Escherichia coli Nissle 1917 (SeNVs@NE-IL32-EcN) to enhance CD8+ T cell-mediated immune responses and overcome immunotherapy resistance.

Single-cell RNA sequencing (scRNA-seq) and transcriptomic analyses were performed to identify key immune cells and regulators involved in CRC immunotherapy resistance, focusing on CD8+ T cells and the regulatory factor IL32. A humanized xenograft mouse model was used to evaluate the impact of IL32 and SeNVs@NE-IL32-EcN on tumor growth and immune responses. The SeNVs@NE-IL32-EcN complex was synthesized through a reverse micelle method and functionalized using extracellular vesicles. Its morphology, size, antioxidant activity, and safety were characterized using electron microscopy, dynamic light scattering (DLS), and in vitro co-culture assays.

Single-cell analyses revealed a significant reduction in CD8+ T cell infiltration in immunotherapy-resistant CRC patients. IL32 was identified as a key regulator enhancing CD8+ T cell cytotoxic activity through granzyme B and IFN-γ secretion. Treatment with SeNVs@NE-IL32-EcN significantly improved the proliferation and activity of CD8+ T cells and reduced tumor progression in humanized mouse models. In vitro and in vivo results demonstrated the complex's biocompatibility, antioxidant properties, and ability to enhance CRC immunotherapy while mitigating immune tolerance.

SeNVs@NE-IL32-EcN offers a novel nano-biomaterial strategy that integrates nanotechnology and probiotic therapy to enhance CD8+ T cell-mediated immunity and overcome CRC immunotherapy resistance. This study lays the foundation for future therapeutic applications in cancer treatment by advancing immune-modulating biomaterials.

Recent studies show that secreted phosphoprotein 1 (SPP1) is linked to the progression of various cancers, including colorectal cancer (CRC). SPP1 also promotes M2 macrophage polarization, contributing to immune evasion in the tumor microenvironment. Tetrahydrocurcumin (THC) has been reported to alleviate CRC, but the mechanism remains unclear.

The study aimed to explore how THC modulated the SPP1/CD44 axis to inhibit M2 polarization and suppress CRC development.

Azoxymethane/dextran sulfate sodium (AOM/DSS)-induced mouse model was used to assess the anti-CRC effects of THC. Transcriptome sequencing was conducted to identify the key targets of THC in CRC. The effects of THC on CRC cells were evaluated by CCK-8, colony formation, migration assays, immunofluorescence staining and flow cytometry. Human monocytic cells, THP-1, and colon cancer cell line, HCT116, were co-cultured, both directly or indirectly, to mimic the tumor-macrophage interactions, and investigate the role of SPP1/CD44 axis and the intervention effect of THC.

THC significantly inhibited CRC carcinogenesis in mice and improved pathologic symptoms, serum inflammatory markers, and intestinal barrier integrity. THC inhibited CRC cell proliferation, migration and colony formation, while promoting apoptosis. Transcriptome analysis identified SPP1 as a key target of THC against CRC. SPP1 facilitated CRC progression by activating the ERK signaling pathway and maintaining the M2-like phenotype of macrophage, which further exacerbated this response. THC inhibited CRC development by targeting the SPP1/CD44 axis, rather than the integrin pathway.

SPP1 played a crucial role in maintaining the M2 phenotype of macrophage and promoting CRC cells proliferation. THC inhibited the activation of ERK signals in CRC cells and phenotypic transformation of M2-like macrophages through the SPP1/CD44 axis, thereby regulating the tumor immune microenvironment to exert anti-CRC effect.

The aberrant accumulation of intracellular disulfides promotes cancer cell disulfidptosis; however, how disulfide stress influences tumour-infiltrating CD8+ T cell function remains unknown. Here we demonstrate that lactate dehydrogenase B (LDHB) facilitates intratumoural CD8+ T cell disulfidptosis and exhaustion, leading to impaired antitumour immunity. SLC7A11-mediated cystine uptake by CD8+ T cells induces disulfidptosis, which plays critical roles in the development of exhausted CD8+ T cells. LDHB restricts glucose-6-phosphate dehydrogenase (G6PD) activity in exhausted CD8+ T cells by interacting with G6PD, causing NADPH depletion and consequently triggering disulfidptosis. Accordingly, the loss of LDHB in T cells prevents disulfidptosis-dependent CD8+ T cell exhaustion and improves antitumour immunity. Mechanistically, STAT3 directs LDHB expression to limit G6PD activity and mediate disulfidptosis in exhausted CD8+ T cells. Our results highlight the distinct roles of disulfidptosis and ferroptosis in driving CD8+ T cell exhaustion and suggest a potential therapeutic strategy to target LDHB in cancer immunotherapy.

Colorectal cancer liver metastasis (CRLM) is a leading cause of death in colorectal cancer (CRC) patients and is characterized by an immunosuppressive tumor microenvironment (TME). This study employs mouse in vivo selection to isolate highly metastatic CRLM derivatives for profiling their transcriptomic, proteomic, and metabolomic alterations associated with CRLM. Notably, the expression of SLAMF3 is significantly upregulated in CRLM derivatives and its knockdown effectively suppresses CRLM in mice. RUNX1 transcriptionally upregulates SLAMF3 expression and combined targeting of the RUNX1/SLAMF3 axis synergistically suppresses liver metastasis in mice. In parallel, SLAMF3 suppresses macrophage-mediated phagocytosis of CRC cells through the SHP-1/2/mTORC1 pathway. Conversely, SLAMF3 knockdown promotes M1 polarization in liver metastases and activates the CCL signaling pathway between macrophages and CD8+ T cells. It also reduces the exhausted CD8+ T cells in liver metastases and the expression of inhibitory receptors PD-1 and TIM-3, thus alleviating the immunosuppressive TME. Clinically, activation of the RUNX1/SLAMF3 axis is closely associated with CRLM progression and correlates with a reduced proportion of clinically beneficial C1QC⁺ tumor-associated macrophages (TAMs). Collectively, these findings identify the RUNX1/SLAMF3 axis as a key driver of immunosuppressive TME remodeling and CRLM progression, highlighting its potential as a promising therapeutic target for CRLM.

Investigating the mechanisms underlying the development of an immunosuppressive microenvironment within colorectal liver metastases (CRLM) is important for identifying synergistic targets for immunotherapy. The regulatory role of tumor-associated macrophage-derived extracellular vesicles (TAM-EVs) in the immune microenvironment of CRLM has not yet been fully explored. Here, we found that TAM-EVs shaped the immunosuppressive microenvironment at the invasive front in murine CRLM models, thus dampening anti-PD-1 immunotherapy. This environment is characterized by an increased tumor stemness potential and abundant neutrophil extracellular traps (NETs) formation. Mechanistically, TAM-EVs-derived fibrinogen-like 2 (FGL2) interacts with the FCGR2B receptor in tumor cells, which further activates a p-STAT3/IL-1β positive feedback loop to increase the stemness potential of cancer cells, whereas IL-1β mediates the communication between cancer cells and neutrophils. The use of an anti-IL-1β monoclonal antibody can reduce NETs production and synergize with anti-PD-1 immunotherapy, which offers clinical translational significance for CRLM therapy. The FGL2/p-STAT3/IL-1β loop correlates with an immunosuppressive microenvironment and poor prognosis in human patients with CRLM. Our results revealed the potential of enhancing the efficacy of immunotherapy via the targeted clearance of NETs using anti-IL-1β monoclonal antibodies, which have significant clinical translational value in the treatment of CRLM.

Liver metastasis of colorectal cancer (CRC) is characterized by a high recurrence rate after surgery, which may be related to the rerecruitment of residual tumor cells by other factors that promote cancer cell growth in the tumor microenvironment. Tumor-associated macrophages (TAMs), as key immune components, showed high expression of secretory phosphoprotein-1 (SPP1) at the site of liver metastasis in colorectal cancer patients. However, the factors and mechanisms driving the elevated expression of SPP1 in TAMs remain poorly understood, as do the potential effects of SPP1 on colorectal cancer progression. In this study, we investigated the factors that contributed to the high expression of SPP1 in TAMs and its role in promoting the M2 polarization of TAMs. Additionally, we examined the direct impact of SPP1 derived from TAMs on the malignant phenotype of colorectal cancer. The results showed that the two major characteristics of the tumor microenvironment-hypoxia and acidity-synergistically increased the expression of SPP1 in TAMs through the HIF-1α/STAT3 signaling pathway, Moreover, elevated SPP1 protein promoted the M2-like polarization of TAMs by reducing mitochondrial damage and affecting metabolic reprogramming. In addition, TAMs-derived SPP1 could directly influence the malignant progression of colorectal cancer by interacting with αvβ3 integrin through paracrine on the surface of cancer cells. Inhibiting HIF-1α involved in the regulation of SPP1 and blocking the direct action of SPP1 with cancer cells could effectively inhibit liver metastasis of CRC. These findings suggested that blocking the upstream signaling pathway of SPP1 or inhibiting its downstream target could be a promising therapeutic strategy to prevent or reduce liver metastasis recurrence in CRC.

Adenosine signaling pathway is a kind of signal regulation hub widely existing in human body, which is involved in a series of physiological processes such as energy supply of body cells. CD73 is a highly concerned signaling protein in purine adenosine pathway, and its role in tumor development and prognosis has been paid more and more attention in recent years, especially in hepatocellular carcinoma (HCC). In this paper, the specific mechanism by which CD73-adenosine signaling regulates tumor microenvironment (TME) of liver cancer tumors was analyzed in detail, highlighting the importance of this pathway as a therapeutic target to combat tumor immunosuppression and enhance the anti-tumor immune response to prevent and treat hepatocellular carcinoma (HCC). In addition, a variety of current targeted therapeutic strategies for adenosine metabolic pathways are summarized, including the development of new drugs in the stage of preclinical research and clinical trials, and the mechanism of action, implementation possibility, and clinical effects of these therapies are discussed. By summarizing the latest scientific research results, in this review, we attempt to paint a panorama of the mechanism of adenosine action in tumor immunotherapy, with the aim to provide a solid theoretical basis and practical guidance for subsequent research and clinical application, ultimately promoting the development of more accurate and efficient tumor immunotherapy.

The optimal chemotherapy backbone and specific population of triple-negative breast cancer (TNBC) patients that benefit from neoadjuvant immunotherapy are not well established. This prospective, single-arm, phase II TREND trial assessed the efficacy and safety of tislelizumab plus nab-paclitaxel and epirubicin/cyclophosphamide-based chemotherapy as a neoadjuvant treatment for TNBC (ChiCTR2000035262). The primary endpoint was pathological complete response (pCR), with the secondary endpoints including safety assessment and objective response rate (ORR). ScRNA-seq, bulk RNA-seq, TCR-seq, cyTOF and WES were performed on pre-treatment and post-treatment samples. Among 53 total enrolled patients, 44 completed the combined neoadjuvant therapy, and 30 of 44 patients (68.18%) achieved pCR. Additionally, 14 out of 44 patients had a complete response (31.82%), with an ORR of 93.18%. The most commonly observed treatment-related adverse events (TRAEs) were alopecia, nausea and liver injury with 6 cases classified as grade 3 or higher adverse events. Immune response-related pathways, including TNF signaling pathway, T cell receptor signaling pathway, were enriched in pCR group. Pre-treatment model was identified and construct to predict response to immunotherapy. CDKN1A+ CD8 T lymphocytes were enriched in pCR group after neoadjuvant immunotherapy. Dynamic change of immune-related pathways at an early stage during the neoadjuvant immunotherapy may be associated with the treatment efficacy. In conclusion, neoadjuvant treatment of tislelizumab with nab-paclitaxel and anthracycline-based chemotherapy showed promising clinical activity and was well-tolerated among TNBC patients, without high incidence of TRAEs. These findings provide evidence supporting neoadjuvant tislelizumab with chemotherapy as an effective rational approach for treating TNBC.

Evidence from observational studies suggests an association between free cholesterol and gastric cancer. Immune cells play a crucial role in the tumor microenvironment of gastric cancer, and free cholesterol can influence immune cells in various ways, thereby impacting gastric cancer. The mechanisms by which free cholesterol regulates and activates the immune response to exert antitumor effects, as well as the causal relationship between free cholesterol and gastric cancer, remain unclear.

We employed a two-sample Mendelian randomization (MR) approach to investigate the causal relationship between 233 metabolites and gastric cancer. Additionally, we validated our findings using data from GWAS databases of similar traits. Using publicly available genetic data, we analyzed the causal relationship between 731 types of immune cells and gastric cancer. Furthermore, we explored the mediating role of regulatory T cells in the causal relationship between free cholesterol and gastric cancer through multivariable Mendelian randomization. Finally, we validated our results using data from the TCGA database and single-cell sequencing data.

We found a causal relationship between free cholesterol levels and gastric cancer (odds ratio [OR] = 0.89, confidence interval [CI] = 0.81-0.98, P < 0.05). We also observed a causal relationship between free cholesterol levels and regulatory T cells (odds ratio [OR] = 0.86, confidence interval [CI] = 0.75-0.98, P < 0.05), and between regulatory T cells and gastric cancer (odds ratio [OR] = 1.04, confidence interval [CI] = 1.01-1.07, P < 0.05). Additionally, our multivariable Mendelian randomization analysis indicated that regulatory T cells mediate the causal relationship between free cholesterol levels and gastric cancer. Furthermore, through single-cell sequencing analysis and data analysis from the TCGA database, we found that the expression of the free cholesterol uptake protein LDLR is negatively correlated with Treg infiltration, which further influences the occurrence and development of gastric cancer.

Our analysis indicates a causal relationship between free cholesterol levels and gastric cancer, with regulatory T cells acting as mediators. Modulating free cholesterol levels to influence regulatory T cells may offer new insights and prospects for the prevention and treatment of gastric cancer.

Macrophages play a critical role in shaping the immune landscape of various diseases, with secreted phosphoprotein 1 (SPP1)-expressing macrophages emerging as a distinct subset implicated in both cancerous and non-cancerous conditions. Leveraging recent advances in single-cell RNA sequencing, numerous studies have identified SPP1+ macrophages across diverse pathological contexts, shedding light on their functional heterogeneity. In cancer, SPP1+ tumour-associated macrophages contribute to tumour growth, angiogenesis, and immune evasion, often interacting with T cells and stromal components to sustain an immunosuppressive microenvironment. Conversely, in non-cancerous diseases, these macrophages exhibit both profibrotic and disease-promoting properties, depending on the tissue context. This review provides a comprehensive synthesis of the latest findings on SPP1+ macrophages, highlighting their roles in tumour progression, immune suppression, tissue remodelling, and fibrosis. By comparing their shared traits and tissue-specific differences, we explore how SPP1+ macrophages adapt to distinct microenvironments and influence disease progression. Understanding their conserved and context-dependent functions may open new avenues for therapeutic targeting.

Ovarian cancer (OC) is a formidable gynecological tumor marked with the highest mortality rate. The lack of effective biomarkers and treatment drugs places a substantial proportion of patients with OC at significant risk of mortality, primarily due to metastasis. Glycolysis metabolism, lipid metabolism, choline metabolism, and sphingolipid metabolism are closely intertwined with the occurrence and progression of OC. Thus, it is of utmost significance to identify potent prognostic biomarkers and delve into the exploration of novel therapeutic drugs and targets, in pursuit of advancing the treatment of OC.

Single-cell RNA sequencing (scRNA-seq) data related to OC were analyzed using AUCell scores to identify subpopulations at the single-cell level. The "AddModuleScore" function of the "Seurat" package was adopted to score and select marker genes from four gene sets: glycolysis metabolism, lipid metabolism, choline metabolism, and sphingolipid metabolism. A prognostic model for metabolism-related genes (MRGs) was constructed and validated using OC-related marker genes selected from bulk RNAseq data. The MRG-based prognostic model was further utilized for functional analysis of the model gene set, pan-cancer analysis of genomic variations, spatial transcriptomics analysis, as well as GO and KEGG enrichment analysis. CIBERSORT and ESTIMATE algorithms were utilized for assessing the immune microenvironment of TCGA-ovarian serous cystadenocarcinoma (OV) samples. Furthermore, the Tracking Tumor Immunophenotype (TIP) database was employed to examine the anti-cancer immune response in patients with OC. To gain a more in-depth understanding of the process, the frequency of somatic mutations and different types of mutated genes were visualized through the somatic mutation profile of the TCGA database. Moreover, the benefits of immune checkpoint inhibitor (ICI) therapy in individuals with OC were predicted in the TIDE database. In addition, the CMap database was used to predict small-molecule drugs for the treatment of OC. Furthermore, immunohistochemistry, RT-qPCR, CCK-8, Transwell assay, and in vivo tumor xenograft experiments were conducted to validate the prognostic ability of the MRG Triggering Receptor Expressed on Myeloid Cells-1 (TREM1) in OC.

Monocytes were selected using AUCell scoring, and two subpopulations of monocytes, marked by the expression of C1QC+ tumor-associated macrophages (TAMs) and FCN1+ resident tissue macrophages (RTMs), were identified as marker genes for OC. Subsequently, a prognostic model consisting of 12 MRGs was constructed and validated. Genomic exploration of the prognostic model unveiled an array of biological functions linked with metabolism. Furthermore, copy number variation (CNV), mRNA expression, single nucleotide variation (SNV), and methylation were significantly different across diverse tumors. Analysis of the TIP database demonstrated that the low-risk group, as determined by the MRG-based prognostic model, exhibited significantly higher anti-cancer immune activity relative to the high-risk group. Furthermore, predictions from the TIDE database revealed that individuals in the high-risk group were more prone to immune evasion when treated with ICIs. The resulting data identified candesartan and PD-123319 as potential therapeutic drugs for OC, possibly acting on the target ATGR2. In vitro and in vivo experiments elucidated that the targeted downregulation of TREM1 effectively inhibited the proliferation and migration of OC cells.

The MRG-based prognostic model constructed through the combined analysis of glycolysis metabolism, lipid metabolism, choline metabolism, and sphingolipid metabolism is potentially effective as a prognostic biomarker. Furthermore, candesartan and PD-123319 may be potential therapeutic drugs for OC, possibly acting on the target ATGR2.

HPV infection is common among women and can result in serious illnesses. This research utilizes single-cell RNA-sequencing (scRNA-seq) to study the connection between cellular heterogeneity and HPV integrations in cervical histopathology. scRNA-seq was used to examine heterogeneity among normal patients and those in three disease stages: high-grade squamous intraepithelial lesions (HSIL), microinvasive carcinoma (MIC), and cervical squamous epithelium carcinoma cancer (CSCC) tissues. A method was developed to identify HPV integration events from scRNA-seq data. Our results indicated an increase in squamous epithelial cells and a decrease in columnar epithelial cells as the disease progressed from normal to CSCC. We discovered HPV genes that were differentially expressed across normal patients and those in the three disease stages. Notably, HPV integration events were more common in squamous epithelial cells at the single-cell level. The ratio of HPV-integrated cells increased as the disease progressed from normal tissue to CSCC, eventually stabilizing. Several genes, such as EGR1, S100A11, S100A8, KRT5, RPL34, ATP1B1, RPS4X and EEF2, were frequently integrated by HPV across patients. In contrast, genes like PAN3, BABAM2, SPEN, TCIM-SIRLNT, TEX41-PABPC1P2 and KCNV1-LINC01608 showed frequent integration events across cells. KRT5, ATP1B1, RPS4X, PAN3 and SPEN were novel recurrent HPV-integrated genes we observed at the patient or cell level in this study. Additionally, we found that HPV genes from various HPV types exhibited integration preferences in various samples and disease stages. This provides a valuable insight into the mechanism of HPV-induced cervical cancer from a single-cell standpoint, highlighting its clinical relevance.

Neoadjuvant anti-PD-1 immunotherapy combined with chemotherapy has shown promising pathologic responses in various cancers, including oral squamous cell carcinoma (OSCC). However, the pathologic response of lymph node (LN) metastases remains poorly understood. This study aims to systematically evaluate the pathologic response rates (pRR) of LN metastases in patients with OSCC and identify potential targets to improve therapeutic outcomes.

We assessed the pRRs of LN metastases and matched primary tumors (PT) in patients with OSCC enrolled in a randomized, two-arm, phase II clinical trial (NCT04649476). Single-cell and spatial transcriptomics and multiplex IHC were performed to analyze the tumor microenvironment and identify potential therapeutic targets in LN metastases. A neoadjuvant orthotopic OSCC mouse model was established to evaluate the therapeutic potential of these targets.

We observed significant heterogeneity in pathologic regression of LN metastases, with lower pRRs compared with PTs. pRRs in LN metastases were correlated with overall and disease-free survival in patients with OSCC. We identified an abundance of macrophages in LN metastases exhibiting an unfolded protein response and activated protein kinase RNA-like endoplasmic reticulum kinase (PERK) signaling. These macrophages contributed to an extracellular matrix-enriched microenvironment through interactions with fibroblasts, which hindered T cell-mediated cytotoxicity. Pharmacologic inhibition of the PERK pathway significantly enhanced anti-PD-1 therapy in LN metastases and PTs in the mouse model.

Our study confirms that the pathologic response of LN metastases in patients with OSCC undergoing neoadjuvant immunotherapy or immunochemotherapy is inferior to that of PTs. It suggests that targeting the PERK pathway in macrophages could be a potential strategy to enhance treatment outcomes.

Colorectal cancer (CRC) is one of the most common malignancies in the world. However, the main causes of metastasis and immune cell infiltration in CRC are still unclear. This experiment was conducted to identify the key genes of metastasis and macrophage infiltration in CRC according to single-cell sequencing (scRNA-seq) data. By analyzing the data of GSE261012 and GSE234804 in the Gene Expression Omnibus (GEO) database, the key node genes for the stages of tumorigenesis, epithelial-mesenchymal transition, and metastasis of CRC were found. These genes were modeled by lasso regression by The Cancer Genome Atlas (TCGA) database, and ZFAND2A was identified as a key gene for metastasis and macrophage infiltration in CRC. Finally, the specific function of ZFAND2A in cancer cell activity was explored in vitro by qRT-PCR, WB analysis, CCK-8, and transwell assay. The specific function of ZFAND2A in macrophage polarization was explored in vitro by qRT-PCR, ELISA, and flow cytometry. We identified crucial gene expression in the entire process of CRC tumor progression, including tumorigenesis, epithelial-mesenchymal transition, and metastasis. Ten thousand six hundred and thirty-seven genes were determined as genes associated with tumor progression and metastasis. Among them, six genes were identified to be related to CRC prognosis. The results of TCGA data indicated that ZFAND2A showed lower expression in tumors and was related to a good prognosis of CRC. Overexpression of ZFAND2A inhibits the proliferation and migration of CRC cells. Additionally, there was a correlation between ZFAND2A expression and macrophage infiltration. Increasing ZFAND2A promotes M1 polarization in macrophages. Our findings provide new potential biomarkers for the metastatic mechanisms and prognosis of CRC. In addition, ZFAND2A is expected to become a potential therapeutic target for CRC.

Malignant tumors represent a significant threat to human health. Among the various therapeutic strategies available, cancer immunotherapy-encompassing adoptive cell transfer (ACT) and immune checkpoint blockade therapy-has emerged as a particularly promising approach following surgical resection, radiotherapy, chemotherapy, and molecular targeted therapies. This form of treatment elicits substantial antigen-specific immune responses, enhances or restores anti-tumor immunity, thereby facilitating the control and destruction of tumor cells, and yielding durable responses across a range of cancers, which can lead to the eradication of tumor lesions and the prevention of recurrence. Tumor-infiltrating lymphocytes (TILs), a subset of ACT, are characterized by their heterogeneity and are found within tumor tissues, where they play a crucial role in mediating host antigen-specific immune responses against tumors. This review aims to explore recent advancements in the understanding of TILs biology, their prognostic implications, and their predictive value in therapeutic contexts.

Metabolic dysfunction-associated steatotic liver disease (MASLD) affects over 30% of the global population and spans a spectrum of liver abnormalities, including simple steatosis, inflammation, fibrosis, cirrhosis, and hepatocellular carcinoma (HCC). Recent studies have identified triggering receptors expressed on myeloid cells 2 (TREM2)-expressing macrophages as key regulators of MASLD progression. TREM2 plays a pivotal role in regulating macrophage-mediated processes such as efferocytosis, inflammatory control, and fibrosis resolution. Additionally, soluble TREM2 (sTREM2) was proposed as a noninvasive biomarker for diagnosing and monitoring MASLD progression. However, the molecular mechanisms through which TREM2 influences MASLD pathogenesis remain incompletely understood. This review summarizes the current understanding of TREM2-expressing macrophages in MASLD, with the goal of illuminating future research and guiding the development of innovative therapeutic strategies targeting TREM2 signaling pathways.

Single-cell transcriptome sequencing technology has been applied to decode the cell types and functional states of immune cells, revealing their tissue-specific gene expression patterns and functions in cancer immunity. Comprehensive assessments of immune cells within and across tissues will provide us with a deeper understanding of the tumor immune system in general. Here, we present Cross-tissue Immune cell type or state Enrichment analysis of gene lists for Cancer (CIEC), the first web-based application that integrates database and enrichment analysis to estimate the cross-tissue immune cell types or states. CIEC version 1.0 consists of 480 samples covering primary tumor, adjacent normal tissue, lymph node, metastasis tissue, and peripheral blood from 323 cancer patients. By applying integrative analysis, we constructed an immune cell type/state map for each context, and adopted our previously developed Kyoto Encyclopedia of Genes and Genomes (KEGG) Orthology Based Annotation System (KOBAS) algorithm to estimate the enrichment for context-specific immune cell types/states. In addition, CIEC also provides an easy-to-use online interface for users to comprehensively analyze the immune cell characteristics mapped across multiple tissues, including expression map, correlation, similar gene detection, signature score, and expression comparison. We believe that CIEC will be a valuable resource for exploring the intrinsic characteristics of immune cells in cancer patients and for potentially guiding novel cancer-immune biomarker development and immunotherapy strategies. CIEC is freely accessible at http://ciec.gene.ac/.

This study investigates key microscopic regions involved in colorectal cancer liver metastasis (CRLM), focusing on the crucial role of cancer-associated fibroblasts (CAFs) in promoting tumor progression and providing molecular- and metabolism-level insights for its diagnosis and treatment using multi-omics. We followed 12 fresh surgical samples from 2 untreated CRLM patients. Among these, 4 samples were used for spatial transcriptomics (ST), 4 for spatial metabolomics, and 4 for single-cell RNA sequencing (scRNA-seq). Additionally, 92 frozen tissue samples from 40 patients were collected. Seven patients were used for immunofluorescence and RT-qPCR, while 33 patients were used for untargeted metabolomics. ST revealed that the spatial regions of CRLM consists of 7 major components, with fibroblast-dominated regions being the most prominent. These regions are characterized by diverse cell-cell interactions, and immunosuppressive and tumor growth-promoting environments. scRNA-seq identified that SPP1+ fibroblasts interact with CD44+ tumor cells, as confirmed through immunofluorescence. Spatial metabolomics revealed suberic acid and tetraethylene glycol as specific metabolic components of this structure, which was further validated by untargeted metabolomics. In conclusion, an SPP1+ fibroblast-rich spatial region with metabolic reprogramming capabilities and immunosuppressive properties was identified in CRLM, which potentially facilitates metastatic outgrowth through interactions with tumor cells.

Functional tumor-specific CD8+ T cells are essential for effective anti-tumor immune response and immune checkpoint inhibitor therapy. Here we show that, compared to other organ sites, primary, metastatic liver tumors in murine models contain a higher number of tumor-specific CD8+ T cells which are also dysfunctional. High-dimensional, multi-omic analysis of patient samples reveals a higher frequency of exhausted tumor-reactive CD8+ T cells and enriched interactions between these cells and SPP1+ macrophages in profibrotic, alpha-SMA rich regions specifically in the liver. Differential pseudotime trajectory inference analysis reveals that extrahepatic signaling promotes an intermediate cell (IC) population in the liver, characterized by co-expression of VISG4, CSF1R, CD163, TGF-βR, IL-6R, and SPP1. Analysis of premetastatic adenocarcinoma patient samples reveals enrichment of this population may predict liver metastasis. These findings suggest a mechanism by which extrahepatic tumors drive liver metastasis by promoting an IC population that inhibits tumor-reactive CD8+ T cell function.

The SPP1+ tumor-associated macrophages (TAMs) have been implicated in tumor metastasis and immune evasion. However, the prognostic significance of SPP1+ TAMs in hepatocellular carcinoma (HCC) remains largely unexplored. This study aimed to identify SPP1+ TAMs-related genes and construct a model to predict overall survival (OS) in HCC patients.

Single-cell RNA sequencing (scRNA-seq) datasets from HCC patients were analyzed to identify SPP1+ TAMs. SPP1+ TAMs-related risk score (STRS) was developed using Mendelian randomization (MR) analysis and Least Absolute Shrinkage and Selection Operator (LASSO) regression. HCC patients from the Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) cohorts were stratified into high- and low-STRS groups based on STRS. Kaplan-Meier survival analysis, receiver operating characteristic (ROC) curve analysis, and functional enrichment analysis were performed to assess the prognostic value of STRS.

SPP1+ TAMs exhibited strong associations with immunosuppressive functions. 16 SPP1+ TAMs-related genes were used to construct STRS. Patients in the high-STRS group had significantly worse OS than those in the low-STRS group (p < 0.001). ROC analysis demonstrated robust predictive power, with AUC values ranging from 0.685 to 0.748 for 1-year OS, 0.717 to 0.739 for 2-year OS, and 0.719 to 0.738 for 3-year OS. The STRS model also exhibited strong predictive capability for the distinction of drug resistance.

This study identified SPP1+ TAMs-related genes as key prognostic indicators in HCC. The STRS model provides an effective tool for predicting patient survival and may facilitate personalized treatment strategies for HCC. These findings enhance the understanding of TAMs-driven immune modulation in HCC and highlight potential therapeutic targets for improving patient outcomes.

Patients with liver metastatic colorectal cancer (mCRC) have a poor prognosis and are the leading cause of death in colorectal cancer (CRC) patients, but the mechanisms associated with CRC metastasis have not been fully elucidated. In this study, we obtained data from the Gene Expression Omnibus database and characterized the single-cell profiles of CRC, mCRC and healthy samples at single-cell resolution, and explored the cells that influence CRC metastasis. We find that AQP1+ CRC identified as highly malignant tumor cells exhibited proliferative and metastatic characteristics. Immunosuppressive properties are present in the tumor microenvironment (TME), while NOTCH3+ Fib is identified to play a facilitating role in the metastatic colonization of CRC. Importantly, we reveal that tumor-associated macrophages (TAM) characterized by SPP1-specific high expression may be involved in TME remodeling through intercellular communication. Specifically, SPP1+ TAM mediates the generation of Fib-derived extracellular vesicle through the APOE-LRP1 axis, which in turn delivers tumor growth-promoting factors in the TME. This study deepens the understanding of the mechanism of TME in mCRC and lays the scientific foundation for the development of therapeutic regimens for mCRC patients.

SPP1+ macrophages have been identified as key players in the colorectal cancer (CRC) tumor microenvironment, but their function remains unclear. This study integrated single-cell and spatial transcriptomics with bulk sequencing to investigate the roles and mechanisms of SPP1 + macrophages in CRC. Our findings revealed a pronounced elevation of SPP1 + macrophages in CRC, especially within tumor territories. These macrophages served as markers for CRC initiation, progression, metastasis, and potential prognosis. Furthermore, they showed heightened transcriptional activity in genes linked to angiogenesis, epithelial-mesenchymal transition, glycolysis, hypoxia, and immunosuppression. SPP1 protein amplified CRC cell migration and invasion, potentially mediating cellular crosstalk via the SPP1-CD44, SPP1-PTGER4, and SPP1-a4b1 complex axes. Patients with a high proportion of SPP1 + macrophages could benefit more from immune checkpoint blockade therapy. Interestingly, CSF1R expression was significantly enriched in C1QC + macrophages versus SPP1 + macrophages, possibly explaining limited anti-CSF1R monotherapy effects. In conclusion, we propose an SPP1 + macrophage model in CRC, highlighting such macrophages as a promising therapeutic target due to their malignancy markers.

BRAF mutation affects the biological characteristics and microenvironment of the tumor during the development of colorectal cancer. Tumor-associated lymph nodes are the key sites of immune response. This study aimed to systematically evaluate the impact of BRAF gene mutations on the remodeling of the CRC immune microenvironment, with a particular focus on their effects on the maturation and function of TLS·In this study, clinical samples of CRC patients were collected, and immune cell subsets were analyzed by single-cell RNA sequencing, and pseudo-temporal locus analysis and spatial transcriptome analysis were performed to explore intercellular communication and functional enrichment analysis. The distribution and maturity of TLS were evaluated by immunohistochemistry and multiple fluorescence staining techniques, and statistical analysis was performed.The results showed that BRAF mutation significantly affected the number and maturity of lymphatic structures infiltrated by tumors, and was negatively correlated with patient prognosis. BRAF mutations lead to alterations in T cell subsets, particularly the dual role of CD4+ CXCL13 cells in TLS maturation. B-cell subpopulation analysis revealed functional deficits in CRC patients with BRAF mutations, which further drove the remodeling of the tumor immune microenvironment.

The very prevalent nature, genetic variability, and intricate tumor microenvironment (TUME) of colorectal cancer (COREC) are its defining features. In order to better understand the molecular and cellular make-up of COREC, this work used single-cell RNA sequencing (SRNAS) to isolate and characterize important cell types as well as their interactions within the TUME. Our analysis of 51,204 cells yielded six distinct types: epithelial, fibroblast, endothelial, T&NK, B, and myeloid. C3 B cells were shown to be the most active in immunological regulation, according to chemokine signaling study, which was one of seven clusters of B cells that were thoroughly subtyped. The examination of copy number variation (CONUV) revealed a great deal of genetic variability, especially in epithelial cells. We traced the activity of three key transcription factor clusters (M1, M2, and M3) across all B cell subtypes using transcription factor analysis. We created a predictive model that correctly sorts patients according to survival results by using marker genes from C3 B cells. In addition, the relationship between genetic changes and the immune system was better understood by tumor mutational burden (TUMUB) and immune infiltration studies. Our research sheds light on the genetic complexity and cellular variety of COREC, which in turn opens up new possibilities for targeted treatments and individualized approaches to patient care.

This study investigates the T-cell receptor (TCR) repertoires in colorectal cancer (CRC) patients by analyzing three distinct datasets: one bulk sequencing dataset of 205 patients with various tumor stages, all newly diagnosed at Sheba Medical Center between 2017 and 2022, with minimal recruitment in 2014 and 2016, and two (public) single-cell sequencing datasets of 10 and 12 patients. Despite the significant variability in the TCR repertoire and the low likelihood of sequence overlap, our analysis reveals an interesting set of TCR sequences across these data. Notably, we observe elevated presence of mucosal-associated invariant T (MAIT) cells in both metastatic and non-metastatic patients. Furthermore, we identify nine identical TCR alpha and TCR beta pairs that appear in both single-cell datasets, with 13 out of 18 sequences from these sequences also appearing in the bulk data. Clinical risk analysis over the bulk dataset, using a subset of these unique sequences, demonstrates a correlation between TCR repertoire disease stage and risk. These findings enhance our understanding of the TCR landscape in CRC and underscore the potential of TCR sequences as biomarkers for disease outcome.

The relationship between immune cells and colorectal cancer (CRC) development has been extensively studied; however, the mediating role of gut microbiota in this relationship remains poorly understood.

We utilized summary data from genome-wide association studies (GWAS) to analyze 731 immune cell phenotypes, 473 gut microbiota, and CRC-related data. A two-step mediation analysis was employed to identify mediating gut microbiota. The primary analysis method was inverse variance weighting (IVW), supplemented by MR-Egger, simple mode, weighted median, and weighted mode analyses. Robustness of the results was ensured through systematic sensitivity analyses.

Our analysis identified 13 immune cell phenotypes significantly associated with CRC, including 10 protective factors and 3 risk factors. Additionally, 13 gut microbiota showed significant associations with CRC, comprising 8 protective factors and 5 risk factors. Mediation analysis revealed that 4-gut microbiota (1 order, 1 family, 1 genus, and 1 unclassified) mediated the relationship between immune cells and CRC. For instance, unclassified CAG - 977 mediated the effects of FSC-A on NK and NKT %lymphocyte on CRC risk, with mediation proportions of 11% and 12.3%, respectively. Notably, 22.3% of the protective effect of EM CD8br %CD8br on CRC was mediated through order Francisellales.

This study provides evidence for a potential causal relationship between immune cells, gut microbiota, and CRC, highlighting the mediating role of specific gut microbiota. These findings offer new insights into the pathogenesis of CRC and may inform future therapeutic strategies.

Lysosomal dysfunction has been implicated in the progression of colon adenocarcinoma (COAD), yet the prognostic significance and therapeutic potential of lysosome-related genes (LRGs) remain underexplored. In this study, we construct a 6-LRG-based prognostic risk stratification model (DPP7, ADAM8, CD1B, LRP2, ATP6V1C2, and PLAAT3) by integrating LASSO and Cox regression analyses. Stratifying patients based on median risk scores, we demonstrate that high-risk patients exhibit significantly worse clinical outcomes across the TCGA cohort and five independent GEO datasets. Furthermore, this panel outperforms 136 previously published models in terms of predictive accuracy for 1-, 3-, and 5-year survival rates. Validation multiplex immunofluorescence using an in-house tissue microarray cohort confirms the 6-LRG signature serves as an independent prognostic factor. Additionally, high-risk patients exhibit distinct immunosuppressive tumor microenvironment and aggressive malignancy characteristics. Functional depletion of DPP7 significantly inhibits tumor cell proliferation, migration, and metastasis in both in vitro and in vivo settings. Moreover, DPP7 silencing attenuates epithelial-mesenchymal transition, as evidenced by the upregulation of E-cadherin and downregulation of N-cadherin, Vimentin, and Snail. In conclusion, this study establishes an LRG-based model for COAD prognostic prediction and nominates DPP7 as a promising therapeutic target for COAD treatment.

Liver metastasis is the most common site of metastasis in colorectal cancer, and the prognosis of colorectal cancer patients with liver metastasis is extremely poor. Revealing the key genes of CLM and implementing targeted interventions is of great significance for colorectal cancer patients. By using the weighted gene co-expression network analysis (WGCNA) algorithm, key gene modules related to metastasis in colorectal cancer were identified. Subsequently, immune-regulating and prognostic-influencing key gene sets were identified from these modules to construct a prognostic model related to colorectal cancer metastasis. Genetic background differences underlying this model were analyzed using colorectal cancer methylation and mutation data, followed by Gene Ontology (GO) analysis and Gene Set Enrichment Analysis (GSEA) analysis of the relevant biological processes associated with the model. The value of predicting tumor drug response through the model was assessed using drug half maximal inhibitory concentration (IC50) data from colorectal cancer cell lines. Subsequently, utilizing single-cell sequencing data about liver metastasis, the colorectal cancer immune microenvironment reflected in the predictive model was analyzed, and a key gene set of the model was identified. Lastly, experimental validation was conducted to investigate the regulatory effects of photodynamic therapy (PDT) on the key genes of the model, and the cytotoxic effect of PDT on colorectal cancer was confirmed. An immune-related gene prognostic model regulating CLM was constructed, consisting of HSPA1A, ULBP2, RBP7, OXT, SLC11A1, INHBB, and ICOS. This model can predict the clinical response of colorectal cancer patients to Oxaliplatin, Cisplatin, Irinotecan, and 5-Fluorouracil. Single-cell sequencing results demonstrate that the model is associated with an immunosuppressive microenvironment in CLM. The higher the model's riskscore, the weaker the MHC-I, MHC-II, and various tumor immune signaling pathway networks in the colorectal cancer microenvironment. Causal analysis reveals that SLC11A1, ICOS, and HSPA1A play key roles in this model. PDT can kill colorectal cancer cells, inhibit colorectal cancer cell metastasis, significantly influence the expression of genes such as SLC11A1, ICOS, and HSPA1A in these processes, and suppress the infiltration of macrophages in the colorectal microenvironment, inhibiting the immune escape process of PD-1/PD-L1. A prognostic model based on immunity regulated by PDT has been established for assessing the prognosis of CLM patients, as well as clinical responses to chemotherapy drugs and immunotherapy.

Despite recent progress in cancer treatment, liver metastases persist as an unmet clinical need. Here, we show that arming liver and tumor-associated macrophages in vivo to co-express tumor antigens (TAs), IFNα, and IL-12 unleashes robust anti-tumor immune responses, leading to the regression of liver metastases. Mechanistically, in vivo armed macrophages expand tumor reactive CD8+ T cells, which acquire features of progenitor exhausted T cells and kill cancer cells independently of CD4+ T cell help. IFNα and IL-12 produced by armed macrophages reprogram antigen presenting cells and rewire cellular interactions, rescuing tumor reactive T cell functions. In vivo armed macrophages trigger anti-tumor immunity in distinct liver metastasis mouse models of colorectal cancer and melanoma, expressing either surrogate tumor antigens, naturally occurring neoantigens or tumor-associated antigens. Altogether, our findings support the translational potential of in vivo armed liver macrophages to expand and rejuvenate tumor reactive T cells for the treatment of liver metastases.

Background/Objectives: Bone metastasis is a frequent and life-threatening event in advanced cancers, affecting up to 70-85% of prostate cancer patients. Understanding the cellular and molecular mechanisms underlying bone metastasis is essential for developing targeted therapies. This study aimed to systematically characterize the heterogeneity and microenvironmental adaptation of prostate cancer bone metastases using single-cell transcriptomics. Methods: We integrated the largest single-cell transcriptome dataset to date, encompassing 124 samples from primary prostate tumors, various bone metastatic sites, and non-malignant tissues (e.g., benign prostatic hyperplasia, normal bone marrow). After quality control, 602,497 high-quality single-cell transcriptomes were analyzed. We employed unsupervised clustering, gene expression profiling, mutation analysis, and metabolic pathway reconstruction to characterize cancer cell subtypes and tumor microenvironmental remodeling. Results: Cancer epithelial cells dominated the tumor microenvironment but exhibited pronounced heterogeneity, posing challenges for conventional clustering methods. By integrating genetic and metabolic features, we revealed key evolutionary trajectories of epithelial cancer cells during metastasis. Notably, we identified a novel epithelial subpopulation, NEndoCs, characterized by unique differentiation patterns and distinct spatial distribution across metastatic niches. We also observed significant metabolic reprogramming and recurrent mutations linked to prostate-to-bone microenvironmental transitions. Conclusions: This study comprehensively elucidates the mutation patterns, metabolic reprogramming, and microenvironment adaptation mechanisms of bone metastasis in prostate cancer, providing key molecular targets and clinical strategies for the precise treatment of bone metastatic prostate cancer.

We conducted a spatial analysis of stage III colorectal adenocarcinomas using Hyperion Imaging Mass Cytometry, examining 52 tumors to assess the tumor microenvironment at the single-cell level. This approach identified 10 distinct cell phenotypes in the tumor microenvironment, including stromal and immune cells, with a subset showing a proliferative phenotype. By focusing on spatial neighborhood interactions and tissue niches, particularly regions with tumor-infiltrating lymphocytes, we investigated how cellular organization relates to clinicopathological and molecular features such as microsatellite instability (MSI) and recurrence. We determined that microsatellite stable (MSS) colorectal cancers had an increased risk of recurrence if they had the following features: 1) a low level of stromal tumor-infiltrating lymphocytes, and 2) low interactions between CD4 + T cells and stromal cells. Our results point to the utility of spatial single-cell interaction analysis in defining novel features of the tumor immune microenvironments and providing useful clinical cell-related spatial biomarkers.

Colorectal cancer (CRC) remains one of the leading causes of cancer-related death worldwide, with increasing incidence in younger ages highlighting the need for new or alternative therapy, of which is immune checkpoint inhibitors. Antibody-based immune checkpoint inhibitors targeting the interaction between programmed cell death protein 1 (PD-1) and programmed death-ligand 1 (PD-L1) have revolutionized cancer treatment, including CRC. However, the low response rate in CRC highlights the need for additional research and innovative therapies. Small molecule inhibitors have risen as another strategy worth exploring, considering their potential to target a wide array of PD-1/PD-L1-related pathways. This review focuses on the potential of small molecule inhibitors targeting the PD-1/PD-L1 axis in CRC. Exploring various classes of small molecule inhibitors, including those that directly block the PD-1/PD-L1 interaction and others that target upstream regulators or downstream signaling pathways involved in PD-1/PD-L1-mediated immune suppression. Additionally, modulation of post-transcriptional and post-translational processes, thereby influencing the expression, stability, or localization of PD-1/PD-L1 proteins to enhance antitumor immunity, provides a multifaceted treatment approach. By disrupting these pathways, these inhibitors can restore immune system activity against tumor cells, offering new hope for overcoming resistance and improving outcomes in CRC patients who do not respond to conventional immune checkpoint inhibitors (ICIs). Integrating these small molecules into CRC treatment strategies could represent a promising advancement in the battle against the challenging disease.