Colorectal Cancer Metastases in the Liver Establish Immunosuppressive Spatial Networking between Tumor-Associated SPP1+ Macrophages and Fibroblasts

Tetrahydrocurcumin alleviates colorectal tumorigenesis by modulating the SPP1/CD44 axis and preventing M2 tumor-associated macrophage polarization

BACKGROUND

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.

PURPOSE

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

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Fibrinogen-like 2 in tumor-associated macrophage-derived extracellular vesicles shapes an immunosuppressive microenvironment in colorectal liver metastases by promoting tumor stemness and neutrophil extracellular traps formation

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.

Cancer-associated fibroblast-derived SEMA3C facilitates colorectal cancer liver metastasis via NRP2-mediated MAPK activation

Liver metastasis remains the predominant cause of mortality in patients with colorectal cancer (CRC). Nevertheless, the mechanisms underlying the initiation of colorectal cancer liver metastasis remain poorly elucidated. During the metastatic process of CRC cells from the primary site to the liver, we performed time-resolved analyses and identified a subset of tumor cells spatially located in the primary tumor and temporally distributed in the early stages of liver metastasis. These cells were termed liver metastasis-initiating cells (LMICs). LMICs exhibit high stemness, low proliferation, active interaction with surrounding stromal components, and a close association with liver metastasis. Notably, we found significant interactions between cancer-associated fibroblasts (CAFs) and LMICs via the SEMA3C-NRP2 receptor-ligand pair. Further in vivo and in vitro experiments confirmed that CAF-secreted SEMA3C could bind to the NRP2 receptor, which activates the MAPK pathway and promotes colorectal cancer liver metastasis. Our findings suggest potential therapeutic strategies for the early prevention of colorectal cancer liver metastasis.

TAMs-derived SPP1, regulated by HIF-1α/STAT3 signaling pathway, influences colorectal cancer malignant progression by activation of EMT via integrin αvβ3

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.

Research progress of CD73-adenosine signaling regulating hepatocellular carcinoma through tumor microenvironment

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.

Tumor-associated macrophages remodel the suppressive tumor immune microenvironment and targeted therapy for immunotherapy

Despite the significant advances in the development of immune checkpoint inhibitors (ICI), primary and acquired ICI resistance remains the primary impediment to effective cancer immunotherapy. Residing in the tumor microenvironment (TME), tumor-associated macrophages (TAMs) play a pivotal role in tumor progression by regulating diverse signaling pathways. Notably, accumulating evidence has confirmed that TAMs interplay with various cellular components within the TME directly or indirectly to maintain the dynamic balance of the M1/M2 ratio and shape an immunosuppressive TME, consequently conferring immune evasion and immunotherapy tolerance. Detailed investigation of the communication network around TAMs could provide potential molecular targets and optimize ICI therapies. In this review, we systematically summarize the latest advances in understanding the origin and functional plasticity of TAMs, with a focus on the key signaling pathways driving macrophage polarization and the diverse stimuli that regulate this dynamic process. Moreover, we elaborate on the intricate interplay between TAMs and other cellular constituents within the TME, that is driving tumor initiation, progression and immune evasion, exploring novel targets for cancer immunotherapy. We further discuss current challenges and future research directions, emphasizing the need to decode TAM-TME interactions and translate preclinical findings into clinical breakthroughs. In conclusion, while TAM-targeted therapies hold significant promise for enhancing immunotherapy outcomes, addressing key challenges-such as TAM heterogeneity, context-dependent plasticity, and therapeutic resistance-remains critical to achieving optimal clinical efficacy.

PERK+ Macrophages Drive Immunotherapy Resistance in Lymph Node Metastases of Oral Squamous Cell Carcinoma

PURPOSE

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.

PATIENTS AND METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Phenotypic heterogeneity and plasticity in colorectal cancer metastasis

Phenotypic heterogeneity and plasticity in colorectal cancer (CRC) has a crucial role in tumor progression, metastasis, and therapy resistance. However, the regulatory factors and the extrinsic signals driving phenotypic heterogeneity remain unknown. Using a combination of single-cell multiomics and spatial transcriptomics data from primary and metastatic CRC patients, we reveal cancer cell states with regenerative and inflammatory phenotypes that closely resemble metastasis-initiating cells in mouse models. We identify an intermediate population with a hybrid regenerative and stem phenotype. We reveal the transcription factors AP-1 and nuclear factor κB (NF-κB) as their key regulators and show localization of these states in an immunosuppressive niche both at the invasive edge in primary CRC and in liver metastasis. We uncover ligand-receptor interactions predicted to activate the regenerative and inflammatory phenotype in cancer cells. Together, our findings reveal regulatory and signaling factors that mediate distinct cancer cell states and can serve as potential targets to impair metastasis.

Intercellular communication between FAP+ fibroblasts and SPP1+ macrophages in prostate cancer via multi-omics

Background

Prostate cancer (PCa) presents substantial heterogeneity and unpredictability in its progression. Despite therapeutic advancements, mortality from advanced PCa remains a significant challenge. Understanding the intercellular communication within the tumor microenvironment (TME) is critical for uncovering mechanisms driving tumorigenesis and identifying novel therapeutic targets.

Methods

We employed an integrative approach combining bulk RNA sequencing, single-cell RNA sequencing (scRNA-seq), and spatial transcriptomics to investigate interactions between FAP+ fibroblasts and tumor-associated macrophages in PCa. Key findings were validated using immunohistochemical and immunofluorescence staining techniques.

Results

Analysis of 23,519 scRNA-seq data from 23 prostate samples revealed a pronounced accumulation of FAP+ fibroblasts in tumor tissues. Spatial transcriptomics and bulk RNA sequencing demonstrated strong associations between FAP+ fibroblasts and SPP1+ macrophages. Notably, tumor-specific intercellular signaling pathways, such as CSF1/CSF1R and CXCL/ACKR1, were identified, highlighting their potential role in fostering an immunosuppressive TME.

Conclusion

Our findings unveil a distinct pattern of crosstalk between FAP+ fibroblasts and SPP1+ macrophages in PCa, shedding light on potential therapeutic targets for advanced PCa.

Conserved spatial subtypes and cellular neighborhoods of cancer-associated fibroblasts revealed by single-cell spatial multi-omics

Cancer-associated fibroblasts (CAFs) are a multifaceted cell population essential for shaping the tumor microenvironment (TME) and influencing therapy responses. Characterizing the spatial organization and interactions of CAFs within complex tissue environments provides critical insights into tumor biology and immunobiology. In this study, through integrative analyses of over 14 million cells from 10 cancer types across 7 spatial transcriptomics and proteomics platforms, we discover, validate, and characterize four distinct spatial CAF subtypes. These subtypes are conserved across cancer types and independent of spatial omics platforms. Notably, they exhibit distinct spatial organizational patterns, neighboring cell compositions, interaction networks, and transcriptomic profiles. Their abundance and composition vary across tissues, shaping TME characteristics, such as levels, distribution, and state composition of tumor-infiltrating immune cells, tumor immune phenotypes, and patient survival. This study enriches our understanding of CAF spatial heterogeneity in cancer and paves the way for novel approaches to target and modulate CAFs.

SPP1 + macrophages cause exhaustion of tumor-specific T cells in liver metastases

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.

Osteopontin promotes tumor microenvironment remodeling and therapy resistance

Osteopontin (OPN) is a multifunctional secretory protein which can be expressed and secreted by a variety of tumor cells and immune cells. Tumor microenvironment remodeling provides favorable conditions for tumor progression, immune escape and therapy resistance. As a bridge molecule in crosstalk between tumor cells and tumor microenvironment, OPN can not only come from tumor cells to regulate the functions of various immune cells, promoting the formation of immunosuppressive environment, but also can be secreted by immune cells to act on tumor cells, leading to tumor progression, thus constructing a positive feedback regulatory network. Here, we summarize the molecular structure, source and receptor of OPN, and clarify the mechanism of OPN on tumor-associated macrophages, dendritic cells, myeloid-derived suppressor cells, tumor progression and therapy resistance to comprehensively understand the great potential of OPN as a tumor biomarker and therapeutic target.

Single cell analysis reveals that SPP1+ macrophages enhance tumor progression by triggering fibroblast extracellular vesicles

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.

LAMA4+ CD90+ eCAFs provide immunosuppressive microenvironment for liver cancer through induction of CD8+ T cell senescence

Despite significant advances in cancer biology research and treatment, clinical outcomes for patients with liver cancer remain unsatisfactory. The biological and molecular mechanisms underlying the bidirectional signaling between tumor cells and the tumor microenvironment (TME), which promotes tumor progression in the liver, remain to be elucidated. Fibroblasts are crucial regulators of tumor progression and response to therapy; however, our understanding of their roles remains limited. Here, we integrated single-cell RNA sequencing and spatial transcriptomic data of pan-liver cancers to characterize the different subtypes of cancer-associated fibroblasts (CAFs). siRNA transfection was used for knockdown the expression of LAMA4. Western blot assay was used for gene expression analysis. Flow cytometry was used to detect proliferation, toxicity and cytolytic capacity of CD8+ T cells. To establish a spontaneous murine hepatocellular carcinoma (HCC) model, a combined DEN and CCL4 approach was performed. Notably, we identified CD90+ extracellular matrix CAFs (eCAFs) associated with poor prognosis. These CD90+ eCAFs, located distal to the tumor nest, overlapped with the distribution of CD8+ T cells. Functional experiments demonstrated that CD90+ eCAFs recruited CD8+ T cells and inhibited their function through secretion of LAMA4. Further investigation revealed that LAMA4 induced the CD8+ T cell senescence through a DNA damage signaling pathway mediated by the receptor ITGA6. In a mouse model of spontaneous HCC, targeting LAMA4 can inhibit the progression of malignant transformation and synergize with anti-PD-1 therapy. Our study reveals the function of specific CAFs subtypes and highlights the importance of interactions with the immune system.

The metabolic underpinnings of sebaceous lipogenesis

Sebaceous glands synthesize and secrete sebum, a mélange of lipids and other cellular products that safeguards the mammalian integument. Differentiating sebocytes delaminate from the basal membrane and dislodge towards the gland's middle, where they eventually undergo a poorly understood death mode in which the whole cell becomes a secretion product (holocrine secretion). Supported by recent transcriptomics data, this review examines the idea that peripheral sebocytes have a remarkable ability to draw nutrients from the blood and become committed to unrestrainedly invest all available resources into synthetic processes for accomplishing sebum synthesis, thereby exploiting core metabolic fluxes as glycogen turnover, glutamine-directed anaplerosis, the pentose phosphate pathway and de novo lipogenesis. Finally, we propose that metabolic-driven processes are an important mechanistic component of holocrine secretion. A deeper understanding of these metabolic adaptations could indicate novel strategies for modulating sebum synthesis, a key pathogenic factor in acne and other skin diseases.

Characterizing macrophage diversity in colorectal malignancies through single-cell genomics

Colorectal cancer (CRC) is one of the most common malignant tumors of the digestive tract, with increasing incidence and mortality rates, posing a significant burden on human health. Its progression relies on various mechanisms, among which the tumor microenvironment and tumor-associated macrophages (TAMs) have garnered increasing attention. Macrophage infiltration in various solid tumors is associated with poor prognosis and is linked to chemotherapy resistance in many cancers. These significant biological behaviors depend on the heterogeneity of macrophages. Tumor-promoting TAMs comprise subpopulations characterized by distinct markers and unique transcriptional profiles, rendering them potential targets for anticancer therapies through either depletion or reprogramming from a pro-tumoral to an anti-tumoral state. Single-cell RNA sequencing technology has significantly enhanced our research resolution, breaking the traditional simplistic definitions of macrophage subtypes and deepening our understanding of the diversity within TAMs. However, a unified elucidation of the nomenclature and molecular characteristics associated with this diversity remains lacking. In this review, we assess the application of conventional macrophage polarization subtypes in colorectal malignancies and explore several unique subtypes defined from a single-cell omics perspective in recent years, categorizing them based on their potential functions.

Intratumoral microbiota-aided fusion radiomics model for predicting tumor response to neoadjuvant chemoimmunotherapy in triple-negative breast cancer

BACKGROUND

Neoadjuvant chemoimmunotherapy (NACI) has emerged as the standard treatment for early-stage triple-negative breast cancer (TNBC). However, reliable biomarkers for identifying patients who are likely to benefit from NACI are lacking. This study aims to develop an intratumoral microbiota-aided radiomics model for predicting pathological complete response (pCR) in patients with TNBC.

METHODS

Intratumoral microbiota are characterized by 16S rDNA sequencing and quantified through experimental assays. Single-cell RNA sequencing is performed to analyze the tumor microenvironment of tumors with various responses to NACI. Radiomics features are extracted from tumor regions on longitudinal magnetic resonance images (MRIs) scanned before and after NACI in the training set. On the basis of treatment response (pCR or non-pCR) and intratumoral microbiota scoring, we select key radiomics features and construct a fusion model integrating multi-timepoint (pre-NACI and post-NACI) MRI to predict the efficacy of immunotherapy, followed by independent external validation.

RESULTS

A total of 124 patients are enrolled, with 88 in the training set and 36 in the validation set. Tumors from patients who achieves pCR present a significantly greater intratumoral microbiota load than tumors from patients who achieve non-pCR (p < 0.05). Additionally, tumors in non-pCR group exhibit greater infiltration of tumor-associated SPP1+ macrophages, which is negatively correlated with the microbiota load. On the basis of intratumoral microbiota scoring, we select 17 radiomics features and use them to construct the fusion radiomics model. The fusion model achieves the highest AUC of 0.945 in the training set, outperforming pre-NACI (AUC = 0.875) and post-NACI (AUC = 0.917) models. In the validation set, this model maintains a superior AUC of 0.873, surpassing those of pre-NACI (AUC = 0.769) and post-NACI (AUC = 0.802) models. Clinically, the fusion model distinguishes patients who achieve pCR from those who do not with an accuracy of 77.8%. Decision curve analysis demonstrates the superior net clinical benefit of this model across varying risk thresholds.

CONCLUSIONS

Our intratumoral microbiota-aided radiomics model could serve as a powerful and noninvasive tool for predicting the response of patients with early-stage TNBC to NACI.

Mapping glioma progression: single-cell RNA sequencing illuminates cell-cell interactions and immune response variability

BACKGROUND

Glioma, the most common primary cancer of the central nervous system, characterizes significant heterogeneity, presenting major challenges for therapeutic approaches and prognosis. In this study, the interactions between malignant glioma cells and macrophages/monocytes, as well as their influence on tumor progression and treatment responses, were explored using comprehensive single-cell RNA sequencing analysis.

METHODS

RNA-seq data from the TCGA and CGGA databases were integrated and an in-depth analysis of glioma samples was performed using single-cell RNA sequencing, functional enrichment analysis, developmental trajectory analysis, cell-cell communication analysis, and gene regulatory network analysis. Furthermore, a prognostic model based on risk scores was developed, and its predictive performance was assessed through immune cell infiltration analysis and immune treatment response evaluation.

RESULTS

Fourteen distinct glioma cellular subpopulations, seven primary cell types, and four macrophage/monocyte subtypes were identified. Developmental trajectory analysis offered insights into the origins and heterogeneity of malignant cells as well as macrophages/monocytes. Cell communication analysis revealed the interaction of macrophages and monocytes with malignant cells through several pathways, including the macrophage migration inhibitory factor and secreted phosphoprotein 1 pathways, engaging in key ligand-receptor interactions that influence tumor behavior. Categorization based on these communication characteristics was significantly correlated with overall survival. Immune cell infiltration analysis highlighted variations in immune cell abundance across different subgroups, possibly linked to differing responses to immunotherapy. This predictive model, comprising 29 prognostic genes, demonstrated high accuracy and robustness across multiple independent cohorts.

CONCLUSION

This study reveals the complex heterogeneity of the glioma microenvironment and enhances the understanding of diverse characteristics of glioma cell subsets. At the same time, it lays a foundation for the development of therapeutic strategies and prognostic models targeting the glioma microenvironment.

Quantifying and interpreting biologically meaningful spatial signatures within tumor microenvironments

The tumor microenvironment (TME) plays a crucial role in orchestrating tumor cell behavior and cancer progression. Recent advances in spatial profiling technologies have uncovered novel spatial signatures, including univariate distribution patterns, bivariate spatial relationships, and higher-order structures. These signatures have the potential to revolutionize tumor mechanism and treatment. In this review, we summarize the current state of spatial signature research, highlighting computational methods to uncover spatially relevant biological significance. We discuss the impact of these advances on fundamental cancer biology and translational research, address current challenges and future research directions.

Integrative single cell transcriptomic analysis reveals 3p deletion associated tumor microenvironment and chemoresistance in head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC) remains a prevalent and lethal malignancy, with a five-year survival rate of just 50% for cases of locally advanced disease. Chromosomal aberrations, particularly the deletion of the short arm of chromosome 3 (3p), have been strongly associated with poor prognosis and more aggressive tumor phenotypes. The tumor microenvironment (TME) plays a pivotal role in tumor progression and resistance to therapy. This study aims to elucidate the impact of 3p deletion on the TME, immune cell infiltration, and treatment response in HNSCC, to identify novel therapeutic targets to improve patient outcomes. We analyzed single-cell RNA sequencing (scRNA-seq) data from the Gene Expression Omnibus (GEO) and bulk transcriptome data from The Cancer Genome Atlas (TCGA). Pseudo-time trajectory and cell-cell communication analyses were performed with the Monocle and CellChat packages. The Wilcoxon test was used to evaluate the differential gene expression between wild-type (wt) and mutant (mut) groups. Prognostic models were developed using the Least Absolute Shrinkage and Selection Operator (LASSO) algorithm and Cox regression analyses to find the genes related to survival, with survival analysis conducted via Kaplan-Meier curves. Gene set enrichment analysis (GSEA) was employed to investigate pathway dysregulation, and immune cell infiltration was assessed using various immune scoring methodologies to explore the differences immune environment. The Tumor Immune Dysfunction and Exclusion (TIDE) database was utilized to predict the potential efficacy of immune checkpoint inhibitors. mRNA and protein expression levels of SPP1 were examined by RT-qPCR and Western blotting, while cell proliferation was assessed using the CCK8 assay. The mut group demonstrated significant alterations in cellular composition, characterized by increased endothelial cells and macrophages and decreased fibroblasts and CD8 + T cells, indicative of an immunosuppressive TME. Differential expression analysis revealed downregulation of immune pathways, including antigen processing and presentation, T cell receptor signaling, and B cell receptor signaling pathways in the mut group, along with enhanced metabolic activity in glycolysis and lipid metabolism. The prognostic model identified nine key genes associated with poor survival in HNSCC. The mut group exhibited poorer overall survival and a more immunosuppressive microenvironment compared to the wt group, which correlated with the outcomes observed in high-risk versus low-risk groups. High-risk patients also showed a diminished response to immunotherapy compared to low-risk patients. Additionally, SPP1 emerged as a critical gene associated with chemotherapy resistance and macrophage M2 polarization. This study demonstrates that 3p deletion significantly reshapes the TME, contributing to poor prognosis in HNSCC by fostering an immunosuppressive environment and enhancing chemoresistance. These findings highlight the potential for developing targeted therapies that address the genetic and immunological landscape of HNSCC.

Pathogenetic development, diagnosis and clinical therapeutic approaches for liver metastasis from colorectal cancer (Review)

Colorectal cancer (CRC) is a prevalent malignancy and a significant proportion of patients with CRC develop liver metastasis (CRLM), which is a major contributor to CRC‑related mortality. The present review aimed to comprehensively examine the pathogenetic development and diagnosis of CRLM and the clinical therapeutic approaches for treatment of this disease. The molecular mechanisms underlying CRLM were discussed, including the role of the tumour microenvironment and epithelial‑mesenchymal transition. The present review also highlighted the importance of early detection and the current challenges in predicting the development of CRLM. Various treatment strategies were reviewed, including surgical resection, chemotherapy and immunotherapy, and the potential of novel therapies, such as selective internal radiation therapy and Traditional Chinese Medicine. Despite recent advancements in treatment options, the treatment of CRLM remains a therapeutic challenge due to the complexity of the liver microenvironment and the heterogeneity of CRC. The present review emphasized the need for a multidisciplinary approach and the integration of emerging therapies to improve patient outcomes.

Analyze the Diversity and Function of Immune Cells in the Tumor Microenvironment From the Perspective of Single-Cell RNA Sequencing

BACKGROUND

Cancer development is closely associated with complex alterations in the tumor microenvironment (TME). Among these, immune cells within the TME play a huge role in personalized tumor diagnosis and treatment.

OBJECTIVES

This review aims to summarize the diversity of immune cells in the TME, their impact on patient prognosis and treatment response, and the contributions of single-cell RNA sequencing (scRNA-seq) in understanding their functional heterogeneity.

METHODS

We analyzed recent studies utilizing scRNA-seq to investigate immune cell populations in the TME, focusing on their interactions and regulatory mechanisms.

RESULTS

ScRNA-seq reveals the functional heterogeneity of immune cells, enhances our understanding of their role in tumor antibody responses, and facilitates the construction of immune cell interaction networks. These insights provide guidance for the development of cancer immunotherapies and personalized treatment approaches.

CONCLUSION

Applying scRNA-seq to immune cell analysis in the TME offers a novel pathway for personalized cancer treatment. Despite its promise, several challenges remain, highlighting the need for further advancements to fully integrate scRNA-seq into clinical applications.

Spatial transcriptomic analysis of tumor microenvironment in esophageal squamous cell carcinoma with HIV infection

BACKGROUND

Human Immunodeficiency Virus (HIV) is one of the most prevalent viruses, causing significant immune depletion in affected individuals. Current treatments can control HIV and prolong patients' lives, but new challenges have emerged. Increasing incidence of cancers occur in HIV patients. Esophageal squamous cell carcinoma (ESCC) is one of the most common cancers observed in HIV patients. However, the spatial cellular characteristics of HIV-related ESCC have not been explored, and the differences between HIV-ESCC and typical ESCC remain unclear.

METHODS

We performed spatial transcriptome sequencing on HIV-ESCC samples to depict the microenvironment and employed cell communication analysis and multiplex immunofluorescence to investigate the molecular mechanism in HIV-ESCC.

RESULTS

We found that HIV-ESCC exhibited a unique cellular composition, with fibroblasts and epithelial cells intermixed throughout the tumor tissue, lacking obvious spatial separation, while other cell types were sparse. Besides, HIV-ESCC exhibited an immune desert phenotype, characterized by a low degree of immune cell infiltration, with only a few SPP1+ macrophages showing immune resistance functions. Cell communication analysis and multiplex immunofluorescence staining revealed that tumor fibroblasts in HIV-ESCC interact with CD44+ epithelial cells via COL1A2, promoting the expression of PIK3R1 in epithelial cells. This interaction activates the PI3K-AKT signaling pathway, which contributes to the progression of HIV-ESCC.

CONCLUSIONS

Our findings depict the spatial microenvironment of HIV-ESCC and elucidate a molecular mechanism in the progression of HIV-ESCC. This will provide us insights into the molecular basis of HIV-ESCC and potential treatment strategies.

The role of macrophages in liver metastasis: mechanisms and therapeutic prospects

Metastasis is a hallmark of advanced cancer, and the liver is a common site for secondary metastasis of many tumor cells, including colorectal, pancreatic, gastric, and prostate cancers. Macrophages in the tumor microenvironment (TME) promote tumor cell metastasis through various mechanisms, including angiogenesis and immunosuppression, and play a unique role in the development of liver metastasis. Macrophages are affected by a variety of factors. Under conditions of hypoxia and increased acidity in the TME, more factors are now found to promote the polarization of macrophages to the M2 type, including exosomes and amino acids. M2-type macrophages promote tumor cell angiogenesis through a variety of mechanisms, including the secretion of factors such as VEGF, IL-1β, and TGF-β1. M2-type macrophages are subjected to multiple regulatory mechanisms. They also interact with various cells within the tumor microenvironment to co-regulate certain conditions, including the creation of an immunosuppressive microenvironment. This interaction promotes tumor cell metastasis, drug resistance, and immune escape. Based on the advent of single-cell sequencing technology, further insights into macrophage subpopulations in the tumor microenvironment may help in exploring new therapeutic targets in the future. In this paper, we will focus on how macrophages affect the TME, how tumor cells and macrophages as well as other immune cells interact with each other, and further investigate the mechanisms involved in liver metastasis of tumor cells and their potential as therapeutic targets.

Identification of pro-fibrotic cellular subpopulations in fascia of gluteal muscle contracture using single-cell RNA sequencing

Fibrosis is a common and integral pathological feature in various chronic diseases, capable of affecting any tissue or organ. Fibrosis within deep fascia is implicated in many myofascial disorders, including gluteal muscle contracture (GMC), Dupuytren's disease, plantar fasciitis, iliotibial band syndrome, and chronic muscle pain. Despite its clinical significance, deep fascia fibrosis remains considerably under-researched compared to other fibrotic conditions. Single-cell RNA-sequencing (scRNA-seq) has been used to investigate cellular heterogeneity in fibrotic tissues. However, to our knowledge, only a few studies have applied scRNA-seq to explore cellular heterogeneity in deep fascia, and none have specifically examined fibrotic fascia. In this study, we performed scRNA-seq analysis on fibrotic fascia associated with GMC and compared them to nonfibrotic control fascial samples. Our findings show that fibroblast and macrophage cells play critical roles in pathological tissue remodeling within fibrotic deep fascia. We observed an upregulation of various collagens, proteoglycans, and extracellular matrix (ECM) glycoproteins in contracture deep fascia, attributed to the widespread activation of fibroblast subclusters. Additionally, two pro-fibrotic macrophage subpopulations, SPP1+ MP and ECM-like MP, appear to facilitate ECM deposition in fibrotic deep fascia by either regulating fibroblast activation or directly contributing to ECM production. The SPP1+ MP and ECM-like MP cells, as well as the signal interaction between SPP1+ MP and fibroblast cells, present potential therapeutic target for treating GMC and other related myofascial disorders.

Single-cell and spatial analysis reveals the interaction between ITLN1+ foam cells and SPP1+ macrophages in atherosclerosis

Introduction

Cardiovascular disease (CVD) caused by atherosclerosis (AS) remains the leading cause of mortality in developed countries. Understanding cellular heterogeneity within the inflammatory microenvironment is crucial for advancing disease management strategies. This study investigates the regulatory functions of distinct cell populations in AS pathogenesis, focusing on the interaction between vascular smooth muscle cell (VSMC)-derived ITLN1+ foam cells and SPP1+ FABP5+ macrophages.

Methods

We employed single-cell RNA sequencing to characterize cell populations within AS plaques. Correlation analyses and the CellChat package were utilized to elucidate intercellular communication networks among various cell types. The functional roles of key subsets of macrophages and VSMCs were assessed using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses. Pseudotime trajectory analysis was conducted to explore the dynamics of VSMC differentiation. Additionally, spatial transcriptomics analysis was used to demonstrate the physical interactions between different cell subpopulations.

Results

We identified significant infiltration of macrophage clusters in AS, with SPP1+ FABP5+ macrophages being highly enriched in AS plaques. These macrophages were associated with lipid transport, storage, and cell migration pathways. A distinct subset of ITLN1+ foam cells derived from VSMCs exhibited robust expression of foam cell markers and lipid metabolism-related genes. Pseudotime trajectory analysis indicated that ITLN1+ foam cells represent a terminal stage of VSMC differentiation, characterized by elevated expression of genes linked to lipid synthesis and AS progression. Spatial transcriptomics and CellChat analysis revealed a significant interaction between ITLN1+ foam cells and SPP1+ FABP5+ macrophages, mediated by the MIF-(CD74 + CD44) and SPP1-CD44 ligand-receptor axes.

Discussion

Our findings underscore the critical crosstalk between ITLN1+ foam cells and SPP1+ macrophages in promoting lipid accumulation and AS progression. Targeting this cell-cell interaction may offer new therapeutic avenues for managing atherosclerosis. Further validation of these mechanisms is necessary to develop effective immunotherapeutic strategies against AS.

Single-cell and spatial-resolved profiling reveals cancer-associated fibroblast heterogeneity in colorectal cancer metabolic subtypes

BACKGROUND

Colorectal cancer (CRC) presents significant treatment challenges due to its high heterogeneity and complex intercellular interactions. Further exploration of CRC subtypes and interactions among tumor-specific clusters will facilitate the development of personalized treatment strategies.

METHODS

Single-cell RNA sequencing and bulk RNA sequencing datasets were integrated to determine CRC metabolic subtypes by hierarchical clustering. The analysis was further extended to cellchat, pseudotime, immune infiltration, and clinicopathological relevance to explore the characteristics of secreted frizzled related protein 2 (SFRP2) + cancer-associated fibroblast (CAF) clusters, and validated by spatial transcriptomics (ST), in vivo experiments, and multiple immunohistochemistry (mIHC).

RESULTS

CRC samples were stably classified into three heterogeneous metabolic subtypes, each exhibiting different microenvironment and CAF heterogeneity, particularly in the distribution of SFRP2 + CAF, which was aligned with metabolic activity. SFRP2 + CAF exhibits high extracellular matrix (ECM) activity and is closely involved in cellular communication, not only promoting the malignant progression of cancer cells but also inducing the differentiation of Tregs. Compared to responders of chemotherapy, the proportion of SFRP2 + CAFs is significantly increased in non-responders. Importantly, mIHC and ST analyses confirm that cancer cells with low expression of agmatinase (AGMAT) can recruit SFRP2 + CAFs, and Treg infiltration surrounding SFRP2 + CAFs was observed. AGMAT combined with oxaliplatin showed the best efficacy in vivo, which may be associated with the inhibition of SFRP2 + CAF infiltration.

CONCLUSIONS

Our study identified and described the potential protumor biological properties of SFRP2 + CAFs, and AGMAT may be a valuable target for disrupting their properties.

Neutrophil-induced pyroptosis promotes survival in patients with hepatoblastoma

BACKGROUND

Hepatoblastoma (HB) is the predominant hepatic malignancy among children. Despite therapeutic options for HB were gradually refined in recent years, patients with metastasis suffer from an unsatisfactory prognosis. Pyroptosis is a type of programmed and inflammatory necrosis. Neutrophils are crucial in innate immunity, which were shown to be associated with tumor progression. Our study strived to unravel the relationship between neutrophil-induced pyroptosis (NIP) and HB.

METHODS

The clinical and bulk RNA sequencing data of 38 patients with HB were obtained from Shanghai Children's Medical Center. We established NIP score based on the LASSO regression. The single-cell RNA sequencing data (GSE186975) were used for for key genes identification, cellular communication, and differentiation trajectories of neutrophils. KEGG, GO, GSVA, and ssGSEA enrichment were used to analyze biological functions, including neutrophil extracellular traps (NETs), NOD-like receptors pathway, neutrophil activation, neutrophil-mediated cytotoxicity, and others.

RESULTS

We constructed a NIP score based on the expression of three genes related to neutrophil and pyroptosis, namely ELANE, CASP1, and NOD2, which was positively correlated with a favorable prognosis of HB. Moreover, we clarified the function of ELANE in HB microenvironmwnt. Immunohistochemistry and transcriptome analysis unraveled a significant correlation between NETs and pyroptosis in HB, suggesting the key role of NETs-related neutrophils in inducing pyroptosis and prolonging survival. We also found upregulated tumor-promoting and immunosuppression-related pathways in the HB microenvironment. In addition, we clarified the growth trajectories and phenotypic changes of neutrophils in the immune microenvironment of HB, which can serve as potential targets for immunotherapy.

CONCLUSIONS

The novel NIP score for patients with HB shows high predictive value for survival. Moreover, we identified biological function, cellular communication, and growth trajectories of neutrophils in HB. Our findings broaden insights into the treatment of HB.

An Analysis Regarding the Association Between DAZ Interacting Zinc Finger Protein 1 (DZIP1) and Colorectal Cancer (CRC)

Colorectal cancer (CRC) is the third most common malignant disease worldwide, and its incidence is increasing, but the molecular mechanisms of this disease are highly heterogeneous and still far from being fully understood. Increasing evidence suggests that fibrosis mediated by abnormal activation of fibroblasts based in the microenvironment is associated with a poor prognosis. However, the function and pathogenic mechanisms of fibroblasts in CRC remain unclear. Here, combining scrna-seq and clinical specimen data, DAZ Interacting Protein 1 (DZIP1) was found to be expressed on fibroblasts and cancer cells and positively correlated with stromal deposition. Importantly, pseudotime-series analysis showed that DZIP1 levels were up-regulated in malignant transformation of fibroblasts and experimentally confirmed that DZIP1 modulates activation of fibroblasts and promotes epithelial-mesenchymal transition (EMT) in tumor cells. Further studies showed that DZIP1 expressed by tumor cells also has a driving effect on EMT and contributes to the recruitment of more fibroblasts. A similar phenomenon was observed in xenografted nude mice. And it was confirmed in xenograft mice that downregulation of DZIP1 expression significantly delayed tumor formation and reduced tumor size in CRC cells. Taken together, our findings suggested that DZIP1 was a regulator of the CRC mesenchymal phenotype. The revelation of targeting DZIP1 provides a new avenue for CRC therapy.

Effects of macrophages in OSCC progression

Macrophages are crucial immune cells within the tumor microenvironment (TME), involved in regulating tumor proliferation, invasion, metastasis, ECM remodeling, angiogenesis, and immunosuppression. Although more and more experimental evidence and clinical data indicate that macrophages are involved in the onset and progression of oral squamous cell carcinoma (OSCC), the exact pathogenesis of OSCC associated with macrophages has not been fully elucidated. Enhanced knowledge of the molecular mechanisms involving macrophages in OSCC will aid in the creation of treatments targeted specifically at macrophages. This review outlines the pro-tumoral and anti-tumoral effects of macrophages in OSCC, emphasizing the interaction between OSCC cells and macrophages. It can provide theoretical basis for the establishment of complex regulatory network centered on macrophages and explore novel therapeutic strategies for OSCC.

Characteristics of successful expansion of tumor-infiltrating lymphocytes from colorectal cancer liver metastasis

Adoptive cell therapy (ACT) utilizing tumor-infiltrating lymphocytes (TILs) has emerged as a successful treatment modality for various malignancies. However, TILs cultured from colorectal cancer (CRC) liver metastasis remain underexplored. Fifteen CRC liver metastasis tissues underwent initial expansion (IE) of TILs and rapid expansion (REP). Histologic examination including the level of stromal TILs and Klintrup-Mäkinen score, were assessed by pathologists and deep learning-derived spatial analysis. We performed correlation analysis between expanded TILs and histopathologic factors. All cases exhibited successful IE, with a mean IE TIL count per fragment and total IE TIL per case of 2.59 ± 2.79e5 cells and 167.79 ± 126.97e5 cells, respectively. Five cases underwent REP, with a median fold change of 3,610 (range, 1,136-4,925). The median CD4+/CD8 + ratio in IE TILs and REP TILs were 3.66 and 0.68, respectively. A significant correlation was observed between the mean number of expanded TILs per fragment and KM score (p = 0.022). Successful expansion of TILs from CRC liver metastasis was achieved. Assessment of KM score may serve as a predictive tool for the obtainable TILs before IE. These findings lay the groundwork for future studies to establish effective ACT in patients with metastatic CRC.

Multi-omic profiling highlights factors associated with resistance to immuno-chemotherapy in non-small-cell lung cancer

Although immune checkpoint blockade (ICB) therapies have shifted the treatment paradigm for non-small-cell lung cancer (NSCLC), many patients remain resistant. Here we characterize the tumor cell states and spatial cellular compositions of the NSCLC tumor microenvironment (TME) by analyzing single-cell transcriptomes of 232,080 cells and spatially resolved transcriptomes of tumors from 19 patients before and after ICB-chemotherapy. We find that tumor cells and secreted phosphoprotein 1-positive macrophages interact with collagen type XI alpha 1 chain-positive cancer-associated fibroblasts to stimulate the deposition and entanglement of collagen fibers at tumor boundaries, obstructing T cell infiltration and leading to poor prognosis. We also reveal distinct states of tertiary lymphoid structures (TLSs) in the TME. Activated TLSs are associated with improved prognosis, whereas a hypoxic microenvironment appears to suppress TLS development and is associated with poor prognosis. Our study provides novel insights into different cellular and molecular components corresponding to NSCLC ICB-chemotherapeutic responsiveness, which will benefit future individualized immuno-chemotherapy.

Genetic and microenvironmental evolution of colorectal liver metastases under chemotherapy

Drug resistance limits the efficacy of chemotherapy for colorectal cancer liver metastasis (CRLM). However, the evolution of CRLM during drug treatment remains poorly elucidated. Multi-omics and treatment response data from 115 samples of 49 patients with CRLM undergoing bevacizumab (BVZ)-based chemotherapy show little difference in genomic alterations in 92% of cases, while remarkable differences are observed at the transcriptomic level. By decoupling intrinsic and acquired resistance, we find that hepatocyte and myeloid cell infiltration contribute to 38.5% and 23.1% of acquired resistance, respectively. Importantly, SMAD4 mutations and chr20q copy-number gain are associated with intrinsic chemoresistance. Gene interference experiments suggest that SMAD4R361H/C mutations confer BVZ and 5-fluorouracil (5-FU) resistance through STAT3 signaling. Notably, supplementing BVZ and 5-FU with the STAT3 inhibitor GB201 restores therapeutic efficacy in SMAD4R361H/C cancer cells. Our study uncovers the evolutionary dynamics of CRLM and its microenvironment during treatment and offers strategies to overcome drug resistance.

Neoadjuvant immunotherapy for dMMR and pMMR colorectal cancers: therapeutic strategies and putative biomarkers of response

Approximately 15% of locally advanced colorectal cancers (CRC) have DNA mismatch repair deficiency (dMMR), resulting in high microsatellite instability and a high tumour mutational burden. These cancers are frequently sensitive to therapy with immune-checkpoint inhibitors (ICIs) in the metastatic setting. This sensitivity seems to be even more pronounced in locally advanced disease, and organ preservation has become a realistic aim in ongoing clinical trials involving patients with dMMR rectal cancer. By contrast, metastatic CRCs with proficient DNA mismatch repair (pMMR) are generally resistant to ICIs, although a proportion of locally advanced pMMR tumours seem to have a high degree of sensitivity to ICIs. In this Review, we describe the current and emerging clinical evidence supporting the use of neoadjuvant ICIs in patients with dMMR and pMMR CRC, and the potential advantages (based on a biological rationale) of such an approach. We discuss how neoadjuvant 'window-of-opportunity' trials are being leveraged to progress biomarker discovery and we provide an overview of potential predictive biomarkers of response to ICIs, exploring the challenges faced when evaluating such biomarkers in biopsy-derived samples. Lastly, we describe how these discoveries might be used to drive a rational approach to trialling novel immunotherapeutic strategies in patients with pMMR CRC, with the ultimate aim of disease eradication and the generation of long-term immunosurveillance.

Revolutionizing prognostic predictions in colorectal cancer: Macrophage‑driven transcriptional insights from single‑cell RNA sequencing and gene co‑expression network analysis

Tumor-associated macrophages have become important biomarkers for cancer diagnosis, prognosis and therapy. The dynamic changes in macrophage subpopulations significantly impact the outcomes of cancer immunotherapy. Hence, identifying additional macrophage-related biomarkers is essential for enhancing prognostic predictions in colorectal cancer (CRC) immunotherapy. CRC single-cell RNA sequencing (scRNA-seq) data was obtained from the Gene Expression Omnibus (GEO) database. The data were processed, normalized and clustered using the 'Seurat' package. Cell types within each cluster were annotated using the 'SingleR' package. Weighted gene co-expression network analysis identified modules corresponding to specific cell types. A non-negative matrix factorization algorithm was employed to segregate different clusters based on the selected module. Differentially expressed genes (DEGs) were identified across various clusters and a prognostic model was constructed using lasso regression and Cox regression analyses. The robustness of the model was validated using The Cancer Genome Atlas (TCGA) database and GEO microarrays. Additionally, the prognosis, immune characteristics and response to immune checkpoint inhibitor (ICI) therapy were individually analyzed. The scRNA-seq data from GSE200997, consisting of 23 samples, were analyzed. Dimensionality reduction and cluster identification allowed the isolation of the primary myeloid cell subpopulations. The macrophage-related brown module was identified, which was further divided into two clusters. Using the DEGs from these clusters, a prognostic model was developed, comprising five macrophage-related genes. The robustness of the model was confirmed using microarray datasets GSE17536, GSE38832 and GSE39582, as well as TCGA cohort. Patients classified as high-risk by the present model exhibited poorer survival rates, lower tumor mutation burden, reduced microsatellite instability, lower tumor purity, more severe tumor immune dysfunction and exclusion, and less benefit from ICIs therapy compared with low-risk patients. The present prognostic model shows promise as a biomarker for risk stratification and predicting therapeutic efficacy in patients with CRC. However, further well-designed prospective studies are necessary to validate the findings.

Biological Roles and Clinical Therapeutic Applications of Tumor-Associated Macrophages in Colorectal Liver Metastasis

Colorectal cancer (CRC) commonly metastasizes to the liver, and this poses a significant clinical challenge. Tumor-associated macrophages (TAMs), key players within the TME, play a significant role in promoting CRC metastasis by secreting various chemokines, growth factors, and cytokines. This review not only aims to enhance our knowledge of TAMs' functions in CRC progression and metastasis but also examines innovative therapeutic strategies to address the clinical problem of colorectal liver metastasis (CLM). By targeting TAMs, we may be able to develop more effective treatments and offer hope to patients suffering from this devastating disease.

Characterization of metastasis-specific macrophages in colorectal cancer for prognosis prediction and immunometabolic remodeling

This study develops a prognostic model to predict metastasis and prognosis in colorectal cancer liver metastases by identifying distinct macrophage subsets. Using scRNA-seq data from primary colorectal cancer and liver metastases, we dissected the cellular landscape to find unique macrophage subpopulations, particularly EEF1G + macrophages, which were prevalent in liver metastases. The study leveraged data from GSE231559, TCGA, and GEO databases to construct an 8-gene risk model named EMGS, based on the EEF1G + macrophage gene signature. Patients were divided into high-risk and low-risk groups using the median EMGS score, with the high-risk group showing significantly worse survival. This group also demonstrated upregulated pathways associated with tumor progression, such as epithelial-mesenchymal transition and angiogenesis, and downregulated metabolic pathways. Moreover, the high-risk group presented an immunosuppressive microenvironment, with a higher TIDE score indicating lower effectiveness of immunotherapy. The study identifies potential drugs targeting the high-risk group, suggesting therapeutic avenues to improve survival. Conclusively, the EMGS score identifies colorectal cancer patients at high risk of liver metastases, highlighting the role of specific macrophage subsets in tumor progression and providing a basis for personalized treatment strategies.

Insights into CSF-1R Expression in the Tumor Microenvironment

The colony-stimulating factor 1 receptor (CSF-1R) plays a pivotal role in orchestrating cellular interactions within the tumor microenvironment (TME). Although the CSF-1R has been extensively studied in myeloid cells, the expression of this receptor and its emerging role in other cell types in the TME need to be further analyzed. This review explores the multifaceted functions of the CSF-1R across various TME cellular populations, including tumor-associated macrophages (TAMs), myeloid-derived suppressor cells (MDSCs), dendritic cells (DCs), cancer-associated fibroblasts (CAFs), endothelial cells (ECs), and cancer stem cells (CSCs). The activation of the CSF-1R by its ligands, colony-stimulating factor 1 (CSF-1) and Interleukin-34 (IL-34), regulates TAM polarization towards an immunosuppressive M2 phenotype, promoting tumor progression and immune evasion. Similarly, CSF-1R signaling influences MDSCs to exert immunosuppressive functions, hindering anti-tumor immunity. In DCs, the CSF-1R alters antigen-presenting capabilities, compromising immune surveillance against cancer cells. CSF-1R expression in CAFs and ECs regulates immune modulation, angiogenesis, and immune cell trafficking within the TME, fostering a pro-tumorigenic milieu. Notably, the CSF-1R in CSCs contributes to tumor aggressiveness and therapeutic resistance through interactions with TAMs and the modulation of stemness features. Understanding the diverse roles of the CSF-1R in the TME underscores its potential as a therapeutic target for cancer treatment, aiming at disrupting pro-tumorigenic cellular crosstalk and enhancing anti-tumor immune responses.

Immune modulation of the liver metastatic colorectal cancer microenvironment via the oral CAPOX-mediated cGAS-STING pathway

We evaluated modulation of the immunosuppressive tumor microenvironment in both local and liver metastatic colorectal cancer (LMCC), focusing on tumor-associated macrophages, which are the predominant immunosuppressive cells in LMCC. We developed an orally administered metronomic chemotherapy regimen, oral CAPOX. This regimen combines capecitabine and a nano-micelle encapsulated, lysine-linked deoxycholate and oxaliplatin complex (OPt/LDC-NM). The treatment effectively modulated immune cells within the tumor microenvironment by activating the cGAS-STING pathway and inducing immunogenic cell death. This therapy modulated immune cells more effectively than did capecitabine monotherapy, the current standard maintenance chemotherapy for colorectal cancer. The macrophage-modifying effect of oral CAPOX was mediated via the cGAS-STING pathway. This is a newly identified mode of immune cell activation induced by metronomic chemotherapy. Moreover, oral CAPOX synergized with anti-PD-1 antibody (αPD-1) to enhance the T-cell-mediated antitumor immune response. In the CT26. CL25 subcutaneous model, combination therapy achieved a 91 % complete response rate with a confirmed memory effect against the tumor. This combination also altered the immunosuppressive tumor microenvironment in LMCC, which αPD-1 monotherapy could not achieve. Oral CAPOX and αPD-1 combination therapy outperformed the maximum tolerated dose for treating LMCC, suggesting metronomic therapy as a promising strategy.

Functional heterogeneity of cancer-associated fibroblasts with distinct neoadjuvant immunotherapy plus chemotherapy response in esophageal squamous cell carcinoma

Novel neoadjuvant immunotherapy combined with chemotherapy (neoICT) has improved outcomes for patients with esophageal squamous-cell carcinoma (ESCC), but challenges persist in low response rates and therapy resistance. Little is known about the intra-tumoral heterogeneity in the ESCC tumor microenvironment (TME) that underlies differential responses to neoadjuvant therapy. We applied single-cell RNA sequencing (scRNA-seq) profiling and multiplexed immunofluorescence staining to thoroughly decipher the TME in ESCC specimens from a neoadjuvant anti-PD1 combination therapy clinical trial. The cancer-associated fibroblasts (CAFs) population showed the significant alteration in abundance following neoadjuvant therapy. Specifically, IL6 + CCL2 + immunomodulatory CAFs and a novel CD248 + mechanoresponsive CAFs subset exhibited increasing infiltration. Mechanistically, CD248 + mechanoresponsive CAFs approached and lined the tumor nest to physically block the infiltration of CD8 + T cells and drug delivery, while IL6 + CCL2 + immunomodulatory CAFs induced therapeutic resistance with distinct IL-6 expression. Among patients treated with neoICT, we observed prominent CAF-T cell interactions. In particular, the NECTIN2-TIGIT ligand-receptor pair was enriched in treated samples, and TIGIT was identified as the major inhibitory checkpoint of T cells. Our findings demonstrate distinct alterations in TME constituent responses to neoadjuvant immunotherapy and identify functional phenotypes of CAFs associated with unfavorable therapeutic responses in patients. This provides potential targets to enhance responses to neoadjuvant therapy in ESCC.

Overexpression of Osteopontin-a and Osteopontin-c Splice Variants Are Worse Prognostic Features in Colorectal Cancer

Background: Osteopontin (OPN) is a glycoprotein involved in various physiological and pathological processes, and its aberrant expression in cancer cells is closely linked to tumor progression. In colorectal cancer (CRC), OPN is overexpressed, but the roles of its splice variants (OPN-SVs), OPNa, OPNb, and OPNc, are not well understood. This study aimed to characterize the expression patterns of OPN-SVs and their potential diagnostic and prognostic implications in CRC using transcriptomic data deposited in TSVdb and TCGA. Methods: The expression patterns of each OPN-SV were analyzed using transcriptomic data deposited in TSVdb and TCGA, which were correlated to patient data available at cBioPortal. Results: Bioinformatic analysis revealed that OPNa, OPNb, and OPNc are overexpressed in CRC samples compared to non-tumor samples. Notably, OPNa and OPNc are overexpressed in CRC stages (II, III, and IV) compared to stage I. Higher levels of OPNa and OPNc transcripts are associated with worse overall survival (OS) and shorter progression-free survival (PFS) in CRC patients. Additionally, the expression of OPNa, OPNb, and OPNc is correlated with BRAFV600E mutations in CRC samples. Conclusions: These findings suggest that OPNa and OPNc, in particular, have potential as diagnostic and prognostic biomarkers, paving the way for their further evaluation in CRC diagnosis and prognosis.

A Paradoxical Tumor Antigen Specific Response in the Liver

Functional tumor-specific CD8+ T cells are essential for an effective anti-tumor immune response and the efficacy of immune checkpoint inhibitor therapy. In comparison to other organ sites, we found higher numbers of tumor-specific CD8+ T cells in primary, metastatic liver tumors in murine tumor models. Despite their abundance, CD8+ T cells in the liver displayed an exhausted phenotype. Depletion of CD8+ T cells showed that liver tumor-reactive CD8+ T failed to control liver tumors but was effective against subcutaneous tumors. Similarly, analysis of single-cell RNA sequencing data from patients showed a higher frequency of exhausted tumor-reactive CD8+ T cells in liver metastasis compared to paired primary colon cancer. High-dimensional, multi-omic analysis combining proteomic CODEX and scRNA-seq data revealed enriched interaction of SPP1+ macrophages and CD8+ tumor-reactive T cells in profibrotic, alpha-SMA rich regions in the liver. Liver tumors grew less in Spp1-/- mice and the tumor-specific CD8+ T cells were less exhausted. Differential pseudotime trajectory inference analysis revealed extrahepatic signaling promoting an intermediate cell (IC) population in the liver, characterized by co-expression of VISG4, CSF1R, CD163, TGF-βR, IL-6R, SPP1. scRNA-seq of a third data set of premetastatic adenocarcinoma showed that enrichment of this population may predict liver metastasis. Our data suggests a mechanism by which extrahepatic tumors facilitate the formation of liver metastasis by promoting an IC population inhibiting tumor-reactive CD8+ T cell function.

Phenotypic and spatial heterogeneity of CD8+ tumour infiltrating lymphocytes

CD8+ T cells are the workhorses executing adaptive anti-tumour response, and targets of various cancer immunotherapies. Latest advances have unearthed the sheer heterogeneity of CD8+ tumour infiltrating lymphocytes, and made it increasingly clear that the bulk of the endogenous and therapeutically induced tumour-suppressive momentum hinges on a particular selection of CD8+ T cells with advantageous attributes, namely the memory and stem-like exhausted subsets. A scrutiny of the contemporary perception of CD8+ T cells in cancer and the subgroups of interest along with the factors arbitrating their infiltration contextures, presented herein, may serve as the groundwork for future endeavours to probe further into the regulatory networks underlying their differentiation and migration, and optimise T cell-based immunotherapies accordingly.

Enhancing cancer immunotherapy: Nanotechnology-mediated immunotherapy overcoming immunosuppression

Immunotherapy is an important cancer treatment method that offers hope for curing cancer patients. While immunotherapy has achieved initial success, a major obstacle to its widespread adoption is the inability to benefit the majority of patients. The success or failure of immunotherapy is closely linked to the tumor's immune microenvironment. Recently, there has been significant attention on strategies to regulate the tumor immune microenvironment in order to stimulate anti-tumor immune responses in cancer immunotherapy. The distinctive physical properties and design flexibility of nanomedicines have been extensively utilized to target immune cells (including tumor-associated macrophages (TAMs), T cells, myeloid-derived suppressor cells (MDSCs), and tumor-associated fibroblasts (TAFs)), offering promising advancements in cancer immunotherapy. In this article, we have reviewed treatment strategies aimed at targeting various immune cells to regulate the tumor immune microenvironment. The focus is on cancer immunotherapy models that are based on nanomedicines, with the goal of inducing or enhancing anti-tumor immune responses to improve immunotherapy. It is worth noting that combining cancer immunotherapy with other treatments, such as chemotherapy, radiotherapy, and photodynamic therapy, can maximize the therapeutic effects. Finally, we have identified the challenges that nanotechnology-mediated immunotherapy needs to overcome in order to design more effective nanosystems.

Determinants of Metastatic Colorectal Cancer With Permanent Liver- Limited Disease

Colorectal cancer (CRC) is a complex and genetically heterogeneous disease presenting a specific metastatic pattern, with the liver being the most common site of metastasis. Around 20%-25% of patients with CRC will develop exclusively hepatic metastatic disease throughout their disease history. With its specific characteristics and therapeutic options, liver-limited disease (LLD) should be considered as a specific entity. The identification of these patients is particularly relevant in view of the growing interest in liver transplantation in selected patients with advanced CRC. Identifying why some patients will develop only LLD remains a challenge, mainly because of a lack of a systemic understanding of this complex and interlinked phenomenon given that cancer has traditionally been investigated according to distinct physiological compartments. Recently, multidisciplinary efforts and new diagnostic tools have made it possible to study some of these complex issues in greater depth and may help identify targets and specific treatment strategies to benefit these patients. In this review we analyze the underlying biology and available tools to help clinicians better understand this increasingly common and specific disease.

[Endothelial cells and fibroblasts mediate the microenvironmental regulatory network of carotid body paraganglioma]

Objective:To explore the gene expression characteristics of endothelial cells and fibroblasts in the microenvironment of SDHD-mutated carotid body tumors（SDHD-CBT）, to fine the functional enrichment of each subcluster, and to further explore the network of cell-cell interactions in the microenvironment of SDHD-CBT. Methods:The bioinformatics analysis was used to download and reanalyze the single-nuclear RNA sequencing data of SDHD-CBT, SDHB mutated thoracic and abdominal paraganglioma（SDHB-ATPGL）, SDHB-CBT, and normal adrenal medulla（NAM）, to clarify the information of cell populations of the samples. We focused on exploring the gene expression profiles of endothelial cells and fibroblasts subclusters, and performed functional enrichment analysis based on Gene Ontology（GO） resources. CellChat was used to compare the cell-cell interactions networks of different clinical samples and predict significant signaling pathways in SDHD-CBT. Results:A total of 7 cell populations were profiled. The main subtypes of endothelial cells in SDHD-CBT are arterial and venous endothelial cells, and the main subtypes of fibroblasts are myofibroblasts and pericytes. Compared to NAM, SDHB-CBT and SDHB-ATPGL, cell communication involving endothelial cells and fibroblasts in SDHD-CBT is more abundant, with significant enrichment in pathways such as FGF, PTN, WNT, PROS, PERIOSTIN, and TGFb. Conclusion:Endothelial cells and fibroblasts in SDHD-CBT are heterogeneous and involved in important cellular interactionprocesses, in which the discovery of FGF，PTN，WNT，PROS，PERIOSTIN and TGFb signals may play an important role in the regulation of microenvironment of SDHD-CBT.

Heterogeneity of hepatocellular carcinoma that responds differently to combination therapy with TACE and Sorafenib as determined by digital spatial gene expression profiling

BACKGROUND

The combination of Sorafenib and transcatheter arterial chemoembolization (TACE) exhibits limited efficacy in the treatment of certain advanced hepatocellular carcinomas (HCC), and the molecular mechanisms underlying resistance to this combination remain unclear.

OBJECTIVE

This study aims to underscore the distinctive contribution of GeoMx DSP technology in elucidating the molecular intricacies of HCC resistance to the Sorafenib and TACE combination.

METHODS

Patients with advanced HCC during the waiting period before liver transplantation were classified into sensitive and resistant groups based on their response to Sorafenib and TACE combination therapy. Employing GeoMx DSP technology for comprehensive gene expression profiling, we identified pivotal molecular targets linked to resistance against combination therapy.

RESULTS

The investigation scrutinized intra-tumoral and inter-individual variances, unveiling a spectrum of crucial molecular targets, such as PLG, PLVAP, immunoglobulin genes, ORM1, and NR4A1, among others. Additionally, we explored signaling pathways associated with treatment responsiveness, including the PPAR signaling pathway. Notably, we emphasized the significance of the immune microenvironment characterized by heightened SPP1 expression in HCC resistance to combination therapy. In the resistant group, SPP1+ tumor-associated macrophage (TAM) infiltration was notably pronounced (p = 0.037), while T-cell depletion showed a mitigated presence (p = 0.013).

CONCLUSION

The study reveals intra- and inter-individual heterogeneity in HCC that is differentially responsive to the combination of Sorafenib and TACE, highlighting multiple key molecular targets associated with treatment resistance. The immune microenvironment is important, and in particular, SPP1+ TAM infiltration may play a key role. Meanwhile, the introduction of immunotherapy in patients resistant to combination therapy may lead to positive results.

Mechanisms of metastatic colorectal cancer

Despite extensive research and improvements in understanding colorectal cancer (CRC), its metastatic form continues to pose a substantial challenge, primarily owing to limited therapeutic options and a poor prognosis. This Review addresses the emerging focus on metastatic CRC (mCRC), which has historically been under-studied compared with primary CRC despite its lethality. We delve into two crucial aspects: the molecular and cellular determinants facilitating CRC metastasis and the principles guiding the evolution of metastatic disease. Initially, we examine the genetic alterations integral to CRC metastasis, connecting them to clinically marked characteristics of advanced CRC. Subsequently, we scrutinize the role of cellular heterogeneity and plasticity in metastatic spread and therapy resistance. Finally, we explore how the tumour microenvironment influences metastatic disease, emphasizing the effect of stromal gene programmes and the immune context. The ongoing research in these fields holds immense importance, as its future implications are projected to revolutionize the treatment of patients with mCRC, hopefully offering a promising outlook for their survival.

The Role of Myeloid Cells on the Development of Hepatic Metastases in Gastrointestinal Cancer

The development of hepatic metastases is the leading cause of mortality in gastrointestinal (GI) cancers and substantial research efforts have been focused on elucidating the intricate mechanisms by which tumor cells successfully migrate to, invade, and ultimately colonize the liver parenchyma. Recent evidence has shown that perturbations in myeloid biology occur early in cancer development, characterized by the initial expansion of specific innate immune populations that promote tumor growth and facilitate metastases. This review summarizes the pathophysiology underlying the proliferation of myeloid cells that occurs with incipient neoplasia and explores the role of innate immune-host interactions, specifically granulocytes and neutrophil extracellular traps, in promoting hepatic colonization by tumor cells through the formation of the "premetastatic niche". We further summarize the role of additional myeloid subpopulations such as monocytes and macrophages, dendritic cells, platelets, and eosinophils on promoting disease metastases in GI cancers. Lastly, we describe burgeoning therapeutic approaches aimed at targeting specific myeloid populations to reduce liver metastases and highlight the inherent challenges that exist in studying the efficacy of these treatments in preclinical models. As the inception and outgrowth of liver metastases are primary drivers of prognosis in GI malignancies; further research into the complex mechanisms involved in this critical process is urgently needed.

Integrating single-cell transcriptomics to reveal the ferroptosis regulators in the tumor microenvironment that contribute to bladder urothelial carcinoma progression and immunotherapy

Background

Ferroptosis, as a novel form of programmed cell death, plays a crucial role in the occurrence and development of bladder cancer (BCa). However, the regulatory mechanisms of ferroptosis in the tumor microenvironment (TME) of BCa remain to be elucidated.

Methods

Based on single-cell RNA (scRNA) transcriptomic data of BCa, we employed non-negative matrix factorization (NMF) dimensionality reduction clustering to identify novel ferroptosis-related cell subtypes within the BCa TME, aiming to explore the biological characteristics of these TME cell subtypes. Subsequently, we conducted survival analysis and univariate Cox regression analysis to explore the prognostic significance of these cell subtypes. We investigated the relationship between specific subtypes and immune infiltration, as well as their implications for immunotherapy. Finally, we discovered a valuable and novel biomarker for BCa, supported by a series of in vitro experiments.

Results

We subdivided cancer-associated fibroblasts (CAFs), macrophages, and T cells into 3-5 small subpopulations through NMF and further explored the biological features. We found that ferroptosis played an important role in the BCa TME. Through bulk RNA-seq analysis, we further verified that ferroptosis affected the progression, prognosis, and immunotherapy response of BCa by regulating the TME. Especially ACSL4+CAFs, we found that high-level infiltration of this CAF subtype predicted worse prognosis, more complex immune infiltration, and less response for immunotherapy. Additionally, we found that this type of CAF was associated with cancer cells through the PTN-SDC1 axis, suggesting that SDC1 may be crucial in regulating CAFs in cancer cells. A series of in vitro experiments confirmed these inferences: SDC1 promoted the progression of BCa. Interestingly, we also discovered FTH1+ macrophages, which were closely related to SPP1+ macrophages and may also be involved in the regulation of BCa TME.

Conclusion

This study revealed the significant impact of ferroptosis on bladder cancer TME and identified novel ferroptosis-related TME cell subpopulations, ACSL4+CAFs, and important BCa biomarker SDC1.