The hypoxia-driven crosstalk between tumor and tumor-associated macrophages: mechanisms and clinical treatment strategies

A turn on fluorescent probe for nitroreductase activity and its application in real-time imaging of tumor hypoxia

Nitroreductase (NTR) is an endogenous reductase overexpressed in hypoxic tumors, with its levels closely correlated to the degree of hypoxia. This correlation has significant clinical implications for the analysis of tumor hypoxia, as it allows for the indirect detection of nitroreductases. Due to their simplicity, noninvasive nature, and excellent spatiotemporal resolution, various fluorescence methods have been developed for the analysis of nitroreductase and tumor hypoxia. In this study, we present the design, synthesis, in vitro evaluation, and biological application of an NTR-activated fluorescent probe, F-NTR. Utilizing an oxanthrene fluorophore as the core component, F-NTR incorporates a 4-nitrobenzene recognition group. This innovative probe, which introduces a nitro group, demonstrates high selectivity and reactivity towards nitroreductase (NTR) due to its reducing properties. Furthermore, probe F-NTR is capable of accurately identifying hypoxic environments, which provides a basis for precise detection and localization of tumors. This work lays the groundwork for future investigations into cell metabolism, tumor metabolism, and the surgical management of solid tumors under hypoxic conditions.

Polysaccharides from traditional Chinese medicine and their nano-formulated delivery systems for cancer immunotherapy

Cancer immunotherapy has evolved into a new generation strategy in the field of anti-tumor treatment. Polysaccharides derived from Traditional Chinese Medicine (TCM) are gaining recognition as powerful immunomodulators in cancer therapy, noted for their multi-target and multi-pathway actions. Owing to their beneficial properties such as water solubility, biocompatibility, and chemical structure modifiability, TCM polysaccharides can also serve as carriers for hydrophobic drugs in the development of innovative drug delivery systems, enhancing synergistic antitumor effects. In this article, we summarize the diverse mechanisms of immunoregulation by TCM polysaccharides in tumor therapy. The applications of these polysaccharides as both active ingredients and drug carriers within nanodelivery systems for cancer immunotherapy are also introduced. Additionally, extensive research on TCM polysaccharides in clinical settings has been collected. Furthermore, discussions are presented on the development prospects and challenges faced by these polysaccharides in the field of tumor immunotherapy. Our goal is to improve researchers' comprehension of TCM polysaccharides in cancer immunotherapy, providing promising strategies to optimize cancer treatment and benefit diverse patient populations.

Emerging nanomedicines for macrophage-mediated cancer therapy

Tumor-associated macrophages (TAMs) contribute to tumor progression by promoting angiogenesis, remodeling the tumor extracellular matrix, inducing tumor invasion and metastasis, as well as immune evasion. Due to the high plasticity of TAMs, they can polarize into different phenotypes with distinct functions, which are primarily categorized as the pro-inflammatory, anti-tumor M1 type, and the anti-inflammatory, pro-tumor M2 type. Notably, anti-tumor macrophages not only directly phagocytize tumor cells, but also present tumor-specific antigens and activate adaptive immunity. Therefore, targeted regulation of TAMs to unleash their potential anti-tumor capabilities is crucial for improving the efficacy of cancer immunotherapy. Nanomedicine serves as a promising vehicle and can inherently interact with TAMs, hence, emerging as a new paradigm in cancer immunotherapy. Due to their controllable structures and properties, nanomedicines offer a plethora of advantages over conventional drugs, thus enhancing the balance between efficacy and toxicity. In this review, we provide an overview of the hallmarks of TAMs and discuss nanomedicines for targeting TAMs with a focus on inhibiting recruitment, depleting and reprogramming TAMs, enhancing phagocytosis, engineering macrophages, as well as targeting TAMs for tumor imaging. We also discuss the challenges and clinical potentials of nanomedicines for targeting TAMs, aiming to advance the exploitation of nanomedicine for cancer immunotherapy.

Nanomaterials-driven in situ vaccination: a novel frontier in tumor immunotherapy

In situ vaccination (ISV) has emerged as a promising strategy in cancer immunotherapy, offering a targeted approach that uses the tumor microenvironment (TME) to stimulate an immune response directly at the tumor site. This method minimizes systemic exposure while maintaining therapeutic efficacy and enhancing safety. Recent advances in nanotechnology have enabled new approaches to ISV by utilizing nanomaterials with unique properties, including enhanced permeability, retention, and controlled drug release. ISV employing nanomaterials can induce immunogenic cell death and reverse the immunosuppressive and hypoxic TME, thereby converting a "cold" tumor into a "hot" tumor and facilitating a more robust immune response. This review examines the mechanisms through which nanomaterials-based ISV enhances anti-tumor immunity, summarizes clinical applications of these strategies, and evaluates its capacity to serve as a neoadjuvant therapy for eliminating micrometastases in early-stage cancer patients. Challenges associated with the clinical translation of nanomaterials-based ISV, including nanomaterial metabolism, optimization of treatment protocols, and integration with other therapies such as radiotherapy, chemotherapy, and photothermal therapy, are also discussed. Advances in nanotechnology and immunotherapy continue to expand the possible applications of ISV, potentially leading to improved outcomes across a broad range of cancer types.

Matrix metalloproteinase-driven epithelial-mesenchymal transition: implications in health and disease

Epithelial-mesenchymal transition (EMT) is a process in which epithelial cells, defined by apical-basal polarity and tight intercellular junctions, acquire migratory and invasive properties characteristic of mesenchymal cells. Under normal conditions, EMT directs essential morphogenetic events in embryogenesis and supports tissue repair. When dysregulated, EMT contributes to pathological processes such as organ fibrosis, chronic inflammation, and cancer progression and metastasis. Matrix metalloproteinases (MMPs)-a family of zinc-dependent proteases that degrade structural components of the extracellular matrix-sit at the nexus of this transition by dismantling basement membranes, activating pro-EMT signaling pathways, and cleaving adhesion molecules. When normally regulated, MMPs promote balanced ECM turnover and support the cyclical remodeling necessary for proper development, wound healing, and tissue homeostasis. When abnormally regulated, MMPs drive excessive ECM turnover, thereby promoting EMT-related pathologies, including tumor progression and fibrotic disease. This review provides an integrated overview of the molecular mechanisms by which MMPs both initiate and sustain EMT under physiological and disease conditions. It discusses how MMPs can potentiate EMT through TGF-β and Wnt/β-catenin signaling, disrupt cell-cell junction proteins, and potentiate the action of hypoxia-inducible factors in the tumor microenvironment. It discusses how these pathologic processes remodel tissues during fibrosis, and fuel cancer cell invasion, metastasis, and resistance to therapy. Finally, the review explores emerging therapeutic strategies that selectively target MMPs and EMT, ranging from CRISPR/Cas-mediated interventions to engineered tissue inhibitors of metalloproteinases (TIMPs), and demonstrates how such approaches may suppress pathological EMT without compromising its indispensable roles in normal biology.

Hypoxia-induced PRPF19 modulates TPT1 alternative splicing to facilitate cisplatin resistance in high-grade serous ovarian cancer

High-grade Serous Ovarian Cancer (HGSOC) is the most common and lethal subtype of ovarian cancer, and chemoresistance is a significant obstacle to its prognosis. The DNA damage response is one of the important mechanisms contributing to chemoresistance. Pre-mRNA processing factor 19 (PRPF19) is essential in DNA damage repair as it can recruit DNA repair proteins. However, the functional role of PRPF19 in HGSOC, especially in chemoresistance, has not been investigated. Herein, we demonstrated that PRPF19 was highly expressed in HGSOC and was associated with poor prognosis. Knockdown of PRPF19 inhibited HGSOC cell proliferation and tumor growth in vivo. In cisplatin-resistant HGSOC cell lines, we observed that knockdown of PRPF19 enhanced cell sensitivity to cisplatin. Mechanistically, PRPF19 silencing induced DNA damage in HGSOC cells, leading to DNA double-strand breaks and ɣH2AX nuclear lesion formation. In addition, mRNA-seq analysis revealed that overexpression of PRPF19 modulates alternative splicing of TPT1, thereby upregulating its expression. Notably, we found that PRPF19 was upregulated under hypoxia. Further examination revealed that hypoxia-inducible factor (HIF)-1α bound to PRPF19 and upregulated PRPF19 expression. In conclusion, these findings suggest that PRPF19 exerts a tumor-promoting effect in HGSOC and may be a novel target for overcoming chemoresistance.

Computational Pathology Detection of Hypoxia-Induced Morphologic Changes in Breast Cancer

Understanding the tumor hypoxic microenvironment is crucial for grasping tumor biology, clinical progression, and treatment responses. This study presents a novel application of artificial intelligence in computational histopathology to evaluate hypoxia in breast cancer. Weakly supervised deep learning models can accurately detect morphologic changes associated with hypoxia in routine hematoxylin and eosin (H&E)-stained whole slide images (WSIs). The HypOxNet model was trained on H&E-stained WSIs from breast cancer primary sites (n = 1016) at ×40 magnification using data from The Cancer Genome Atlas. Hypoxia Buffa signature was used to measure hypoxia scores, which ranged from -43 to 47, and stratified the samples into hypoxic and normoxic based on these scores. This stratification represented the weak labels associated with each WSI. HypOxNet achieved an average area under the curve of 0.82 on test sets, identifying significant differences in cell morphology between hypoxic and normoxic tissue regions. Importantly, once trained, the HypOxNet model required only the readily available H&E-stained slides, making it especially valuable in low-resource settings where additional gene expression assays are not available. These artificial intelligence-based hypoxia detection models can potentially be extended to other tumor types and seamlessly integrated into pathology workflows, offering a fast, cost-effective alternative to molecular testing.

Integrated single-cell and bulk transcriptomic analysis identifies a novel macrophage subtype associated with poor prognosis in breast cancer

BACKGROUND

Tumor-associated macrophages (TAMs) are pivotal components of the breast cancer (BC) tumor microenvironment (TME), significantly influencing tumor progression and response to therapy. However, the heterogeneity and specific roles of TAM subpopulations in BC remain inadequately understood.

METHODS

We performed an integrated analysis of single-cell RNA sequencing (scRNA-seq) and bulk RNA sequencing (RNA-seq) data from BC patients to comprehensively characterize TAM heterogeneity. Utilizing the MetaTiME computational framework and consensus clustering, we identified distinct TAM subtypes and assessed their associations with clinical outcomes and treatment responses. A machine learning-based predictive model was developed to evaluate the prognostic significance of TAM-related gene expression profiles.

RESULTS

Our analysis revealed three distinct TAM subgroups. Notably, we identified a novel macrophage subtype, M_Macrophage-SPP1-C1Q, characterized by high expression of SPP1 and C1QA, representing an intermediate differentiation state with unique proliferative and oncogenic properties. High infiltration of M_Macrophage-SPP1-C1Q was significantly associated with poor overall survival (OS) and chemotherapy resistance in BC patients. We developed a Random Forest (RF)-based predictive model, Macro.RF, which accurately stratified patients based on survival outcomes and chemotherapy responses, independent of established prognostic parameters.

CONCLUSION

This study uncovers a previously unrecognized TAM subtype that drives poor prognosis in BC. The identification of M_Macrophage-SPP1-C1Q enhances our understanding of TAM heterogeneity within the TME and offers a novel prognostic biomarker. The Macro.RF model provides a robust tool for predicting clinical outcomes and guiding personalized treatment strategies in BC patients.

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.

Immune Cell-NSPC interactions: Friend or foe in CNS injury and repair?

Neural stem/progenitor cells (NSPCs) play a crucial role in central nervous system (CNS) development, regeneration, and repair. However, their functionality and therapeutic potential are intricately modulated by interactions with immune cells, particularly macrophages and microglia. Microglia, as CNS-resident macrophages, are distinct from peripheral macrophages in their roles and characteristics, contributing to specialized functions within the CNS. Recent evidence suggests that microglia, as CNS-resident macrophages, contribute to the quality assurance of NSPCs by eliminating stressed or dysfunctional cells, yet the mechanisms underlying this process remain largely unexplored. Furthermore, macrophage polarization states, such as M1 and M2, appear to differentially influence NSPC quality, potentially impacting neurogenesis and regenerative outcomes. Identifying surface markers indicative of NSPC stress could provide a strategy for selecting optimal cells for transplantation therapies. Additionally, in vivo clonal labeling approaches may enable precise tracking of NSPC fate and their interactions with immune cells. Beyond macrophages and microglia, the roles of other immune cells, including T cells and neutrophils, particularly in injury and neurodegenerative disease contexts, in the context of CNS injury and disease are emerging areas of interest. Here, I discuss the emerging evidence supporting the interplay between the immune system and NSPCs, highlighting critical gaps in knowledge and proposing future research directions to harness immune-mediated mechanisms for optimizing neural regeneration and transplantation strategies.

An on-Demand Oxygen Nano-vehicle Sensitizing Protein and Nucleic Acid Drug Augment Immunotherapy

Hypoxia severely limits the antitumor immunotherapy for breast cancer. Although efforts to alleviate tumor hypoxia and drug delivery using diverse nanostructures achieve promising results, the creation of a versatile controllable oxygen-releasing nano-platform for co-delivery with immunostimulatory molecules remains a persistent challenge. To address this problem, a versatile oxygen controllable releasing vehicle PFOB@F127@PDA (PFPNPs) is developed, which effectively co-delivered either protein drug lactate oxidase (LOX) or nucleic acids drug unmethylated cytosine-phosphate-guanine oligonucleotide (CpG ODNs). Upon photothermal heating, this platform triggered oxygen release, thereby augmenting LOX-mediated lactate detection rates, and improving T cells infiltrating and cytokine expression. Moreover, under an oxygenated tumor microenvironment (TME), PFPNPs co-delivered with CpG ODNs effectively reprogrammed the immunosuppressive TME by repolarizing macrophages to an M1-like phenotype, promoting dendritic cells maturation, and increasing tumor-infiltrating T cells while decreasing the ratio of regulatory T cells (Tregs). Our study demonstrated that this controlled oxygen-releasing platform possessed adaptive drug-loading capabilities to meet varied immunotherapeutic demands in clinical settings.

Injured Myocardium-Targeted Theranostic Nanoplatform for Multi-Dimensional Immune-Inflammation Regulation in Acute Myocardial Infarction

Pyroptosis is a key mode of programmed cell death during the early stages following acute myocardial infarction (AMI), driving immune-inflammatory responses. Cardiac resident macrophages (CRMs) are the primary mediators of cardiac immunity, and they serve a dual role through their shaping of both myocardial injury and post-AMI myocardial repair. To appropriately regulate AMI-associated inflammation, HM4oRL is herein designed, an innovative bifunctional therapeutic nanoplatform capable of inhibiting cardiomyocyte pyroptosis while reprogramming inflammatory signaling. This HM4oRL platform is composed of a core of 4-Octyl itaconate (4-OI)-loaded liposomes, a middle layer consisting of a metal-polyphenol network (MPN) film, and an optimized outer hybrid immune-cell membrane layer. The unique properties of this hybrid membrane layer facilitated HM4oRL targeting to the injured myocardium during early-stage AMI in mice, whereupon the release of 4-Ol and modified MPN synergistically inhibited cardiomyocyte pyroptosis while suppressing inflammatory monocytes/macrophage responses at the infarcted site. Mechanistically, HM4oRL preserved cardiac metabolic homeostasis through AMPK signaling activation, establishing favorable microenvironmental conditions for the reprogramming of CRM-mediated inflammation. Ultimately, HM4oRL treatment is able to resolve inflammation, enhance neovascularization, and suppress myocardial fibrosis, reducing the infarct size and enhancing post-AMI cardiac repair such that it is an innovative approach to the targeted treatment of AMI.

M2 Macrophage-Derived Exosomal circ_0088494 Inhibits Ferroptosis via Promoting H3K4me1 Modification of STEAP3 in Cutaneous Squamous Cell Carcinoma

Cutaneous squamous cell carcinoma (cSCC) is a common type of cutaneous cancer globally. M2 macrophage-derived exosomes (M2 exosomes) facilitate the development of cancer. Ferroptosis, a newly uncovered form of cell death, is linked to cancer progression. The present research planned to study the function and potential mechanism of M2 exosomes on ferroptosis in cSCC. Patients with cSCC were recruited to gather adjacent noncancerous specimens and cSCC tissues. Mononuclear macrophage (THP-1) cells were differentiated into M2 macrophages before exosome extraction, and then the exosomes were added into cSCC cells (A431 and SCL-1). Erastin was applied to induce ferroptosis. Cell viability, mitochondrial superoxide, lipid-ROS, malondialdehyde (MDA), and iron level were detected to validate ferroptosis in cSCC cells. Proteins and RNAs were tested by applying western blot and RT-qPCR. The combination between molecules was validated by ChIP and RIP. Six-transmembrane epithelial antigen of the prostate 3 (STEAP3) was elevated in cSCC specimens, which correlated to reduced ferroptosis. cSCC tissues presented an increase in the number of M2 macrophages. Erastin-elicited ferroptosis was repressed by M2 macrophages, while exosome inhibitor GW4869 neutralized the outcome of M2 macrophages. Furthermore, M2 exosomes repressed ferroptosis of cSCC cells via circ_0088494, which might be related to the upregulation of STEAP3. M2 exosomes-derived circ_0088494 promoted histone 3 lysine 4 monomethylation (H3K4me1) modification of STEAP3 by recruiting histone-lysine N-methyltransferase 2D (KMT2D). The effect of circ_0088494-silenced M2 exosomes on ferroptosis was antagonized by STEAP3 overexpression. M2 exosomes-derived circ_0088494 recruited KMT2D to promote H3K4me1 modification of STEAP3, thereby inhibiting ferroptosis in cSCC. This study might provide a novel target for cSCC treatment.

PLIN2 Promotes Lipid Accumulation in Ascites-Associated Macrophages and Ovarian Cancer Progression by HIF1α/SPP1 Signaling

A major characteristic of ovarian cancer (OC) is its unique route of metastasis via ascites. The immune microenvironment in ascites remains understudied, leaving the mechanism of ascites-mediated abdominal metastasis obscure. Here, a single-cell transcriptomic landscape of CD45+ immune cells across multiple anatomical sites is depicted, including primary tumors, metastatic lesions, and ascites, from patients diagnosed with high-grade serous ovarian carcinoma (HGSOC). A novel subset of perilipin 2 high (PLIN2hi) macrophages are identified that are enriched in ascites and positively correlated with OC progression, hence being designated as "ascites-associated macrophages (AAMs)". AAMs are lipid-loaded with overexpression of the lipid droplet protein PLIN2. Overexpression or suppression of PLIN2 can enhance or inhibit tumor cell migration, invasion, and vascular permeability in vitro, which is also confirmed in vivo. Mechanistically, it is demonstrated that PLIN2 boosts HIF1α/SPP1 signaling in macrophages, thereby exerting pro-tumor functions. Finally, a PLIN2-targeting liposome is designed to efficiently suppress ascites production and tumor metastasis. Taken together, this work provides a comprehensive characterization of the cancer-promoting function and lipid-rich property of ascites-enriched PLIN2hi macrophages, establishes a link between lipid metabolism and hypoxia within the context of the ascites microenvironment, and elucidates the pivotal role of ascites in trans-coelomic metastasis of OC.

Manganese dioxide-based in situ vaccine boosts antitumor immunity via simultaneous activation of immunogenic cell death and the STING pathway

In situ vaccine (ISV) can activate the anti-tumor immune system by inducing immunogenic cell death (ICD) at the tumor site. However, the development of tumor ISV still faces challenges due to insufficient tumor antigens released by tumor cells and the existence of tumor immunosuppressive microenvironment (TIME). Targeting the STING pathway has been reported to enhance the adjuvant effects of in situ tumor vaccines by initiating innate immunity. Based on this, we developed a potent in situ cancer vaccine, MBMA-RGD ISV, which simultaneously induces ICD and activates the STING pathway to achieve sustained anti-tumor immunity. Specifically, a water-soluble prodrug Mit-ALA was synthesized from the chemotherapeutic agent mitoxantrone (Mit) and the photosensitizer precursor 5-aminolevulinic acid (5-ALA) by pH-responsive ester bonds, which was then loaded into pre-synthesized BSA-MnO2 nanoparticles and functionalized with the targeting Arg-Gly-Asp (RGD) peptide to obtain MBMA-RGD ISV. This ISV actively targets tumor cells by binding integrin receptors and then gradually releases antitumor components in response to tumor microenvironment (TME). The released 5-ALA is metabolized in mitochondria to produce photosensitizer PpIX. Under laser irradiation, the photodynamic property of PpIX coupled with the photothermal effect of Mit synergistically induced ICD, resulting in the release of tumor antigens and evoking adaptive immunity. Meanwhile, released Mn2+ and Mit synergistically activate the STING pathway by inducing DNA damage, further enhancing antitumor immunity. Moreover, large amounts of oxygen released by MnO2 relieved the hypoxia microenvironment, thus sensitizing photodynamic therapy and improving the immunosuppressive state of TME. Therefore, MBMA-RGD ISV efficiently activates systemic antitumor immunity in vitro and in vivo, providing new strategies and ideas for the development of tumor ISV. STATEMENT OF SIGNIFICANCE: Using a biocompatible BSA-MnO2 nanoplatform, we developed a dual-prodrug tumor in situ vaccine (ISV) with tumor microenvironment-responsive action for synergistic cancer immunotherapy. Once internalized by tumor cells, the MBMA-RGD ISV responded to intracellular H+, H2O2, and GSH, releasing its therapeutic "cargo." Under laser irradiation, the combined effects of photodynamic therapy (PDT) and photothermal therapy (PTT) induced immunogenic cell death (ICD), effectively recruiting and stimulating dendritic cells (DCs). Concurrently, STING pathway activation, triggered by DNA damage, enhanced DC maturation. Moreover, the MnO2 component alleviated hypoxia within the tumor microenvironment by releasing significant amounts of oxygen, which facilitated the repolarization of macrophages from the M2 phenotype to the M1 phenotype. Therefore, MBMA-RGD ISV demonstrated potent suppression of tumor metastasis and recurrence without notable side effects in mouse tumor models.

From silent partners to potential therapeutic targets: macrophages in colorectal cancer

Cancer cells grow and survive in the tumor microenvironment, which is a complicated process. As a key part of how colorectal cancer (CRC) progresses, tumor-associated macrophages (TAMs) exhibit a double role. Through angiogenesis, this TAM can promote the growth of cancers. Although being able to modify and adjust immune cells is a great advantage, these cells can also exhibit anti-cancer properties including direct killing of cancer cells, presenting antigens, and aiding T cell-mediated responses. The delicate regulatory mechanisms between the immune system and tumors are composed of a complex network of pathways regulated by several factors including hypoxia, metabolic reprogramming, cytokine/chemokine signaling, and cell interactions. Decoding and figuring out these complex systems become significant in building targeted treatment programs. Targeting TAMs in CRC involves disrupting chemokine signaling or adhesion molecules, reprogramming them to an anti-tumor phenotype using TLR agonists, CD40 agonists, or metabolic modulation, and selectively removing TAM subsets that promote tumor growth. Multi-drug resistance, the absence of an accurate biomarker, and drug non-specificity are also major problems. Combining macrophage-targeted therapies with chemotherapy and immunotherapy may revolutionize treatment. Macrophage studies will advance with new technology and multi-omics methodologies to help us understand CRC and build specific and efficient treatments.

The immunometabolic topography of tuberculosis granulomas governs cellular organization and bacterial control

Despite being heavily infiltrated by immune cells, tuberculosis (TB) granulomas often subvert the host response to Mycobacterium tuberculosis (Mtb) infection and support bacterial persistence. We previously discovered that human TB granulomas are enriched for immunosuppressive factors typically associated with tumor-immune evasion, raising the intriguing possibility that they promote tolerance to infection. In this study, our goal was to identify the prime drivers for establishing this tolerogenic niche and to determine if the magnitude of this response correlates with bacterial persistence. To do this, we conducted a multimodal spatial analysis of 52 granulomas from 16 non-human primates (NHP) who were infected with low dose Mtb for 9-12 weeks. Notably, each granuloma's bacterial burden was individually quantified allowing us to directly ask how granuloma spatial structure and function relate to infection control. We found that a universal feature of TB granulomas was partitioning of the myeloid core into two distinct metabolic environments, one of which is hypoxic. This hypoxic environment associated with pathologic immune cell states, dysfunctional cellular organization of the granuloma, and a near-complete blockade of lymphocyte infiltration that would be required for a successful host response. The extent of these hypoxia-associated features correlated with worsened bacterial burden. We conclude that hypoxia governs immune cell state and organization within granulomas and is a potent driver of subverted immunity during TB.

CCL20 in the tumor microenvironment: implications for cancer progression and therapeutic approaches

Increasing knowledge of the immunosuppressive tumor microenvironment in cancer-related processes has led to the developing of novel immune-based therapies that have changed the cancer treatment paradigm. In the tumor microenvironment, the plethora of soluble factors secreted by tumor cells interacts with immune cells and non-immune components to deliver signals necessary for tumor progression. Accordingly, targeting tumor-derived factors inducing this immunosuppressive tumor microenvironment has become an appealing therapeutic potential in advancing cancer treatment. CCL20, a chemokine best known to induce leucocyte migration in response to pathological and inflammatory conditions, has been implicated in tumor proliferation, angiogenesis, metastasis, immunosuppression, and therapeutic resistance. Notably, CCL20 and its receptor CCR6 are important in tumor microenvironment interactions. This review discusses the interaction between the CCL20-CCR6 axis and the tumor microenvironment and how these interactions promote tumor progression. Also, an outline of studies utilizing CCL20 in combination with other standard cancer treatments has been shed.

Ultrasonic-Controlled Drug Release Prevents Protumorigenic Transition and Improves Sequential Targeting Effect to Enhance Treatment of Residual Hepatocellular Carcinoma

Insufficient radio-frequency ablation (IRFA) of hepatocellular carcinoma accelerates the recurrence of residual tumor, leading to a poor prognosis. Neutrophils (NEs), as the initial leukocytes to infiltrate the IRFA-associated inflammatory area, were utilized as drug carriers due to their inherent chemotactic properties for targeted delivery of chemotherapy drugs to the inflammatory site where residual tumor persists post-IRFA. Previous research has highlighted that the immunosuppressive cytokines in the tumor microenvironment could promote the transition of NEs into a protumorigenic phenotype. However, it is unclear whether NEs used as drug delivery carriers undergo similar changes and how this transition affects treatment effectiveness. Here, we present novel findings demonstrating the phenotypic transition of NEs in the residual tumor microenvironment from an antitumorigenic to a protumorigenic state following IRFA treatment. More critically, we found for the first time that NE carriers undergo a comparable phenotypic transition in the residual tumor, thereby attenuating the therapeutic outcome. Ingeniously, coloading NE carriers with perfluorohexane not only enabled ultrasound imaging but also facilitated spatiotemporally controllable drug release through ultrasound irradiation, thus preventing the protumorigenic transition of NE carriers and maintaining an inflammatory microenvironment at the residual tumor zone. This significantly improved the sequential targeting effect of NE carriers and ultimately enhanced the treatment of residual tumor post-IRFA. Our study provided novel insights into the modulatory role of the immune microenvironment on the phenotypic transition of live NE carriers in the drug delivery system and presented a strategy to prevent adverse effects and enhance residual tumor treatment.

Immune Cell Interactions and Immune Checkpoints in the Tumor Microenvironment of Gastric Cancer

Gastric cancer (GC) ranks as the fifth most prevalent malignant neoplasm globally, with an increased death rate despite recent advancements in research and therapeutic options. Different molecular subtypes of GC have distinct interactions with the immune system, impacting the tumor microenvironment (TME), prognosis, and reaction to immunotherapy. Tumor-infiltrating lymphocytes (TILs) in the TME are crucial for preventing tumor growth and metastasis, as evidenced by research showing that patients with GC who have a significant density of TILs have better survival rates. But cancer cells have evolved a variety of mechanisms to evade immune surveillance, both sialic acid-binding immunoglobulin-like lectin 15 (Siglec-15) and Programmed Death-Ligand 1 (PD-L1) playing a pivotal role in the development of an immunosuppressive TME. They prevent T cell activation and proliferation resulting in a decrease in the immune system's capacity to recognize and eliminate malignant cells. These immune checkpoint molecules function via different but complementary mechanisms, the expression of Siglec-15 being mutually exclusive with PD-L1 and, therefore, providing a different therapeutic approach. The review explores how TILs affect tumor growth and patient outcomes in GC, with particular emphasis on their interactions within the TME and potential targeting of the PD-L1 and Siglec-15 pathways for immunotherapy.

Understanding the Dual Role of Macrophages in Tumor Growth and Therapy: A Mechanistic Review

Macrophages are heterogeneous cells that are the mediators of tissue homeostasis. These immune cells originated from monocytes and are classified into two basic categories, M1 and M2 macrophages. M1 macrophages exhibit anti-tumorous inflammatory reactions due to the behavior of phagocytosis. M2 macrophages or tumor-associated macrophages (TAMs) are the most abundant immune cells in the tumor microenvironment (TME) and have a basic role in tumor progression by interacting with other immune cells in TME. By the expression of various cytokines, chemokines, and growth factors, TAMs lead to strengthening tumor cell proliferation, angiogenesis, and suppression of the immune system which further support invasion and metastasis. This review discusses recent and updated mechanisms regarding tumor progression by M2 macrophages. Moreover, the current therapeutic approaches targeting TAMs, their advantages, and limitations are also summarized, and further treatment approaches are outlined along with an elaboration of the tumor regression role of macrophages. This comprehensive review article possibly helps to understand the mechanisms underlying the tumor progression and regression role of macrophages in a comparative way from a basic level to the advanced one.

Regulation of PHD2 by HIF-1α in Erythroid Cells: Insights into Erythropoiesis Under Hypoxia

The hypoxia-inducible factor (HIF) pathway has been demonstrated to play a pivotal role in the process of high-altitude adaptation. PHD2, a key regulator of the HIF pathway, has been found to be associated with erythropoiesis. However, the relationship between changes in Phd2 abundance and erythroid differentiation under hypoxic conditions remains to be elucidated. A hemin-induced K562 erythroid differentiation model was used to explore the effects of PHD2 knockdown under hypoxia. Erythroid differentiation was assessed by flow cytometry and immunofluorescence. HIF-1α's regulation of PHD2 was examined using luciferase assays and ChIP-seq. CRISPR/Cas9 was applied to knock out EGLN1 and HIF1A, and a fluorescent reporter system was developed to track PHD2 expression. PHD2 knockdown enhanced erythroid differentiation, evident by increased CD71 and CD235a expression. Reporter assays and ChIP-seq identified an HIF-1α binding site in the EGLN1 5' UTR, confirming HIF-1α as a regulator of PHD2 expression. The fluorescent reporter system provided real-time monitoring of endogenous PHD2 expression, showing that HIF-1α significantly modulates PHD2 levels under hypoxic conditions. PHD2 influences erythropoiesis under hypoxia, with HIF-1α regulating its expression. This feedback loop between HIF-1α and PHD2 sheds light on mechanisms driving erythroid differentiation under low-oxygen conditions.

Hypoxia-responsive liposome enhances intracellular delivery of photosensitizer for effective photodynamic therapy

Liposomes, especially polyethylene glycol (PEG)-modified long-circulating liposomes, have been approved for market use, due to good biocompatibility, passive tumor targeting, and sustained drug release. PEG-modified long-circulating liposomes address issues such as poor stability and rapid clearance by the reticuloendothelial system. However, they still face challenges like hindering drug uptake by tumor cells and preventing tumor penetration. Inspired by the hypoxic tumor microenvironment, we constructed a hypoxia-responsive liposome (PAO-L) to enhance the intracellular uptake and photodynamic therapy (PDT) effect of chlorin e6 (Ce6). The intelligent hypoxia-cleavable PEG-AZO-OA (PAO) was prepared by coupling PEG and octadecylamine (OA) to hypoxia-sensitive azobenzene-4,4'-dicarboxylic acid (AZO) through amide reaction. The synthesized PAO was further incorporated into Ce6-loaded liposomes to enhance the circulation stability, while promote the tumor penetration and internalization by the responsive shedding of PEG from liposome surface upon reaching the hypoxic tumor tissue. PAO-L mediated PDT significantly inhibited the growth of B16F10 and 4T1 tumors, as well as lung metastasis of 4T1 breast cancer. The excellent therapeutic effect and good tolerability make PAO-L a promising candidate for enhanced PDT.

Biopsy location and tumor-associated macrophages in predicting malignant glioma recurrence using an in-silico model

Predicting the biological behavior and time to recurrence (TTR) of high-grade diffuse gliomas (HGG) after maximum safe neurosurgical resection and combined radiation and chemotherapy plays a pivotal role in planning clinical follow-up, selecting potentially necessary second-line treatment and improving the quality of life for patients diagnosed with a malignant brain tumor. The current standard-of-care (SoC) for HGG includes follow-up neuroradiological imaging to detect recurrence as early as possible and relies on several clinical, neuropathological, and radiological prognostic factors, which have limited accuracy in predicting TTR. In this study, using an in-silico analysis, we aim to improve predictive power for TTR by considering the role of (i) prognostically relevant information available through diagnostics used in the current SoC, (ii) advanced image-based information not currently part of the standard diagnostic workup, such as tumor-normal tissue interface (edge) features and quantitative data specific to biopsy positions within the tumor, and (iii) information on tumor-associated macrophages. In particular, we introduced a state-of-the-art spatio-temporal model of tumor-immune interactions, emphasizing the interplay between macrophages and glioma cells. This model serves as a synthetic reality for assessing the predictive value of various features. We generated a cohort of virtual patients based on our mathematical model. Each patient's dataset includes simulated T1Gd and Fluid-attenuated inversion recovery (FLAIR) MRI volumes. T1-weighted imaging highlights anatomical structures with high contrast, providing clear detail on brain morphology, whereas FLAIR suppresses fluid signals, improving the visualization of lesions near fluid-filled spaces, which is particularly helpful for identifying peritumoral edema. Additionally, we simulated results on macrophage density and proliferative activity, either in a specified part of the tumor, namely the tumor core or edge ("localized"), or unspecified ("non-localized"). To enhance the realism of our synthetic data, we imposed different levels of noise. Our findings reveal that macrophage density at the tumor edge contributed to a high predictive value of feature importance for the selected regression model. Moreover, there are lower MSE values for the "localized" biopsy in prediction accuracy toward recurrence post-resection compared with "non-localized" specimens in the noisy data. In conclusion, the results show that localized biopsies provided more information about tumor behavior, especially at the interface of tumor and normal tissue (Edge).

The Physiological and Therapeutic Role of CD47 in Macrophage Function and Cancer

BACKGROUND

Immunotherapy is an emerging strategy in cancer therapeutics aimed at modulating the immune system to inhibit pro-tumor pathways and increase a tumor's sensitivity to chemotherapy. Several clinically approved immunotherapy treatments, such as monoclonal antibody treatments, have been successful in solid tumors such as breast, colorectal, and pancreatic. However, an outstanding challenge of these strategies is tumor cell resistance. One target of interest for immune cell modulation is targeting macrophages that enter the tumor microenvironment. More specifically, an immune checkpoint of interest is CD47. CD47 is a transmembrane protein that inhibits phagocytic activity by acting as a "don't eat me" signal. In both mice and humans, healthy cells can express CD47, while solid malignancies like colorectal and breast cancer express it most strongly.

METHODS

Analysis of literature data on the physiological and functional roles of tissue-resident macrophages, along with the structure and mechanisms of action of the CD47 pathway was explored. We also explored how CD47 can influence different aspects of the tumor microenvironment (i.e. cellular metabolism and hypoxia) in addition to current clinical strategies and challenges associated with targeting CD47.

RESULTS

Overall, it was discovered that CD47 is overexpressed in a variety of cancer types in addition to normal tissue, making it a promising treatment regimen to enhance the capability of macrophages to phagocytose tumor cells. However, treatment efficacy is varied in pre-clinical and clinical models due to various challenges such as off-target effects.

CONCLUSION

This review emphasizes the diverse functionality of macrophages in normal and cancerous tissue, while also emphasizing the importance of macrophage targeting and their clinical significance.

ZFP36L2 Is a Potential Prognostic Marker of IL1β+ Osteosarcoma

Background: Osteosarcoma stands as the predominant bone malignancy afflicting children and young adults. Despite strides in treatment, the enduring reality is that the long-term survival rates for patients grappling with recurrences and metastases linger at a mere 30%. This underscores the pressing demand for novel prognostic markers and therapeutic avenues to improve outcomes and offer hope to those battling this formidable disease. ZFP36L2, a member of the tristetraprolin family of CCCH zinc finger proteins, stands out for its pivotal role in posttranscriptional modifications and its ability to modify tumor microenvironments. Methods: We obtained RNA-seq data from TCGA and GTEx cohorts to investigate the expression of ZFP36L2 in tumor and normal tissues. We also utilized GO/KEGG analysis and immune infiltration analysis to verify the relationship between ZFP36L2 and immune cells. A Kaplan-Meier survival curve was used to study the relationship between ZFP36L2 and IL1β in osteosarcoma. Single-cell data analysis and cell-cell communication analysis were used to discover the therapeutic potential of ZFP36L2 in osteosarcoma. Results: This study elucidates the specific expression pattern of ZFP36L2 in tumors. ZFP36L2 is associated with metastasis in sarcoma, but has no statistically significant correlation with survival rate. ZFP36L2 has been shown to be associated with T cells and macrophages in the tumor microenvironment through GO/KEGG analysis and immune infiltration analysis. The survival analysis results show that ZFP36L2 can serve as a biomarker in IL1β+ osteosarcoma. Single-cell sequencing analysis shows that ZFP36L2 is present in IL1β+ macrophages. Cell-cell communication analysis indicates that ZFP36L2 targets TNF in IL1β+ osteosarcoma, thereby improving prognosis. Conclusions: ZFP36L2 has potential as a prognostic marker in IL1β+ osteosarcoma patients.

The Role of Macrophages in Hepatocellular Carcinoma and Their Therapeutic Potential

Hepatocellular carcinoma (HCC) represents a significant clinical burden globally and is predicted to continue to increase in incidence for the foreseeable future. The treatment of HCC is complicated by the fact that, in the majority of cases, it develops on a background of advanced chronic inflammatory liver disease. Chronic inflammation can foster an immunosuppressive microenvironment that promotes tumour progression and metastasis. In this setting, macrophages make up a major immune component of the HCC tumour microenvironment, and in this review, we focus on their contribution to HCC development and progression. Tumour-associated macrophages (TAMs) are largely derived from infiltrating monocytes and their potent anti-inflammatory phenotype can be induced by factors that are found within the tumour microenvironment, such as growth factors, cytokines, hypoxia, and extracellular matrix (ECM) proteins. In general, experimental evidence suggest that TAMs can exhibit a variety of functions that aid HCC tumour progression, including the promotion of angiogenesis, resistance to drug therapy, and releasing factors that support tumour cell proliferation and metastasis. Despite their tumour-promoting profile, there is evidence that the underlying plasticity of these cells can be targeted to help reprogramme TAMs to drive tumour-specific immune responses. We discuss the potential for targeting TAMs therapeutically either by altering their phenotype within the HCC microenvironment or by cell therapy approaches by taking advantage of their infiltrative properties from the circulation into tumour tissue.

Candida albicans-Derived β-Glucan as a Novel Modulator of Tumor Microenvironment: Targeting Macrophage Polarization and Inducing Ferroptosis in Lung Cancer

Introduction

Tumor-associated macrophages (TAMs) play a crucial role in the tumor microenvironment (TME), and their polarization state significantly influences patient outcomes. This study investigates the inhibitory effects of β-glucan extracted from Candida albicans on lung cancer progression, focusing on its impact on TAM polarization and the induction of ferroptosis, a form of regulated cell death.

Methods

Utilizing both in vivo animal models and in vitro cellular assays, we assessed the impact of β-glucan on tumor growth, cellular proliferation, and migration. We evaluated TAM polarization by analyzing the expression of M1 and M2 markers and identified differentially expressed genes (DEGs) related to ferroptosis. The role of ferroptosis in TAM polarization was further confirmed by assessing the protein levels of ACSL4 and GPX4, intracellular ferrous ion levels, and lipid peroxides.

Results

β-glucan treatment significantly reduced tumor size and weight, along with cellular proliferation and migration, suggesting a potent suppressive effect on lung cancer cell growth. β-glucan promoted an M1-like phenotype in TAMs, as evidenced by increased CD86 expression and decreased CD206 expression, and modulated cytokine mRNA levels. RNA sequencing analysis post β-glucan treatment identified a substantial number of DEGs enriched in the ferroptosis pathway. The induction of ferroptosis by β-glucan was further confirmed through the significant upregulation of ACSL4 and downregulation of GPX4, alongside increased intracellular ferrous ion levels and lipid peroxides. The ferroptosis inhibitor Fer-1 abrogated these effects, highlighting the specificity of β-glucan-mediated polarization.

Conclusion

These results collectively provide novel insights into the immunotherapeutic potential of β-glucan from Candida albicans and its role in modulating TAM polarization and lung cancer growth, offering a promising avenue for cancer treatment strategies.

Myofibroblast-derived exosomes enhance macrophages to myofibroblasts transition and kidney fibrosis

A critical event in the pathogenesis of kidney fibrosis is the transition of macrophages into myofibroblasts (MMT). Exosomes play an important role in crosstalk among cells in the kidney and the development of renal fibrosis. However, the role of myofibroblast-derived exosomes in the process of MMT and renal fibrosis progression remains unknown. Here, we examined the role of myofibroblast-derived exosomes in MMT and kidney fibrogenesis. In vitro, transforming growth factor-β1 stimulated the differentiation of kidney fibroblasts into myofibroblasts and promoted exosome release from myofibroblasts. RAW264.7 cells were treated with exosomes derived from myofibroblasts. We found purified exosomes from myofibroblasts trigger the MMT. By contrast, inhibition of exosome production with GW4869 or exosome depletion from the conditioned media abolished the ability of myofibroblasts to induce MMT. Mice treatment with myofibroblast-derived exosomes (Myo-Exo) exhibited severe fibrotic lesion and more abundant MMT cells in kidneys with folic acid (FA) injury, which was negated by TANK-banding kinase-1 inhibitor. Furthermore, suppression of exosome production reduced collagen deposition, extracellular matrix protein accumulation, and MMT in FA nephropathy. Collectively, Myo-Exo enhances the MMT and kidney fibrosis. Blockade of exosomes mediated myofibroblasts-macrophages communication may provide a novel therapeutic target for kidney fibrosis.

TDERS, an exosome RNA-derived signature predicts prognosis and immunotherapeutic response in clear cell renal cell cancer: a multicohort study

Background

Tumor-derived exosomes are involved in tumor progression and immune invasion and might function as promising noninvasive approaches for clinical management. However, there are few reports on exosom-based markers for predicting the progression and adjuvant therapy response rate among patients with clear cell renal cell carcinoma (ccRCC).

Methods

The signatures differentially expressed in exosomes from tumor and normal tissues from ccRCC patients were correspondingly deregulated in ccRCC tissues. We adopted a two-step strategy, including Lasso and bootstrapping, to construct a novel risk stratification system termed the TDERS (Tumor-Derived Exosome-Related Risk Score). During the testing and validation phases, we leveraged multiple external datasets containing over 2000 RCC cases from eight cohorts and one inhouse cohort to evaluate the accuracy of the TDERS. In addition, enrichment analysis, immune infiltration signatures, mutation landscape and therapy sensitivity between the high and low TDERS groups were compared. Finally, the impact of TDERS on the tumor microenvironment (TME) was also analysed in our single-cell datasets.

Results

TDERS consisted of 12 mRNAs deregulated in both exosomes and tissues from patients with ccRCC. TDERS achieved satisfactory performance in both prognosis and immune checkpoint inhibitor (ICI) response across all ccRCC cohorts and other pathological types, since the average area under the curve (AUC) to predict 5-year overall survival (OS) was larger than 0.8 across the four cohorts. Patients in the TDERS high group were resistant to ICIs, while mercaptopurine might function as a promising agent for those patients. Patients with a high TDERS were characterized by coagulation and hypoxia, which induced hampered tumor antigen presentation and relative resistance to ICIs. In addition, single cells from 12 advanced samples validated this phenomenon since the interaction between dendritic cells and macrophages was limited. Finally, PLOD2, which is highly expressed in fibro- and epi‑tissue, could be a potential therapeutic target for ccRCC patients since inhibiting PLOD2 altered the malignant phenotype of ccRCC in vitro.

Conclusion

As a novel, non-invasive, and repeatable monitoring tool, the TDERS could work as a robust risk stratification system for patients with ccRCC and precisely inform treatment decisions about ICI therapy.

Targeting of TAMs: can we be more clever than cancer cells?

АBSTRACT: With increasing incidence and geography, cancer is one of the leading causes of death, reduced quality of life and disability worldwide. Principal progress in the development of new anticancer therapies, in improving the efficiency of immunotherapeutic tools, and in the personification of conventional therapies needs to consider cancer-specific and patient-specific programming of innate immunity. Intratumoral TAMs and their precursors, resident macrophages and monocytes, are principal regulators of tumor progression and therapy resistance. Our review summarizes the accumulated evidence for the subpopulations of TAMs and their increasing number of biomarkers, indicating their predictive value for the clinical parameters of carcinogenesis and therapy resistance, with a focus on solid cancers of non-infectious etiology. We present the state-of-the-art knowledge about the tumor-supporting functions of TAMs at all stages of tumor progression and highlight biomarkers, recently identified by single-cell and spatial analytical methods, that discriminate between tumor-promoting and tumor-inhibiting TAMs, where both subtypes express a combination of prototype M1 and M2 genes. Our review focuses on novel mechanisms involved in the crosstalk among epigenetic, signaling, transcriptional and metabolic pathways in TAMs. Particular attention has been given to the recently identified link between cancer cell metabolism and the epigenetic programming of TAMs by histone lactylation, which can be responsible for the unlimited protumoral programming of TAMs. Finally, we explain how TAMs interfere with currently used anticancer therapeutics and summarize the most advanced data from clinical trials, which we divide into four categories: inhibition of TAM survival and differentiation, inhibition of monocyte/TAM recruitment into tumors, functional reprogramming of TAMs, and genetic enhancement of macrophages.

Crosstalk of pyroptosis and cytokine in the tumor microenvironment: from mechanisms to clinical implication

In the realm of cancer research, the tumor microenvironment (TME) plays a crucial role in tumor initiation and progression, shaped by complex interactions between cancer cells and surrounding non-cancerous cells. Cytokines, as essential immunomodulatory agents, are secreted by various cellular constituents within the TME, including immune cells, cancer-associated fibroblasts, and cancer cells themselves. These cytokines facilitate intricate communication networks that significantly influence tumor initiation, progression, metastasis, and immune suppression. Pyroptosis contributes to TME remodeling by promoting the release of pro-inflammatory cytokines and sustaining chronic inflammation, impacting processes such as immune escape and angiogenesis. However, challenges remain due to the complex interplay among cytokines, pyroptosis, and the TME, along with the dual effects of pyroptosis on cancer progression and therapy-related complications like cytokine release syndrome. Unraveling these complexities could facilitate strategies that balance inflammatory responses while minimizing tissue damage during therapy. This review delves into the complex crosstalk between cytokines, pyroptosis, and the TME, elucidating their contribution to tumor progression and metastasis. By synthesizing emerging therapeutic targets and innovative technologies concerning TME, this review aims to provide novel insights that could enhance treatment outcomes for cancer patients.

The Hippo Pathway in Breast Cancer: The Extracellular Matrix and Hypoxia

As one of the most prevalent malignant neoplasms among women globally, the optimization of therapeutic strategies for breast cancer has perpetually been a research hotspot. The tumor microenvironment (TME) is of paramount importance in the progression of breast cancer, among which the extracellular matrix (ECM) and hypoxia are two crucial factors. The alterations of these two factors are predominantly regulated by the Hippo signaling pathway, which promotes tumor invasiveness, metastasis, therapeutic resistance, and susceptibility. Hence, this review focuses on the Hippo pathway in breast cancer, specifically, how the ECM and hypoxia impact the biological traits and therapeutic responses of breast cancer. Moreover, the role of miRNAs in modulating ECM constituents was investigated, and hsa-miR-33b-3p was identified as a potential therapeutic target for breast cancer. The review provides theoretical foundations and potential therapeutic direction for clinical treatment strategies in breast cancer, with the aspiration of attaining more precise and effective treatment alternatives in the future.

Using Multi-Omics Analysis to Explore Diagnostic Tool and Optimize Drug Therapy Selection for Patients with Glioma Based on Cross-Talk Gene Signature

Background

The heterogeneity of prognosis and treatment benefits among patients with gliomas is due to tumor microenvironment characteristics. However, biomarkers that reflect microenvironmental characteristics and predict the prognosis of gliomas are limited. Therefore, we aimed to develop a model that can effectively predict prognosis, differentiate microenvironment signatures, and optimize drug selection for patients with glioma.

Materials and Methods

The CIBERSORT algorithm, bulk sequencing analysis, and single-cell RNA (scRNA) analysis were employed to identify significant cross-talk genes between M2 macrophages and cancer cells in glioma tissues. A predictive model was constructed based on cross-talk gene expression, and its effect on prognosis, recurrence prediction, and microenvironment characteristics was validated in multiple cohorts. The effect of the predictive model on drug selection was evaluated using the OncoPredict algorithm and relevant cellular biology experiments.

Results

A high abundance of M2 macrophages in glioma tissues indicates poor prognosis, and cross-talk between macrophages and cancer cells plays a crucial role in shaping the tumor microenvironment. Eight genes involved in the cross-talk between macrophages and cancer cells were identified. Among them, periostin (POSTN), chitinase 3 like 1 (CHI3L1), serum amyloid A1 (SAA1), and matrix metallopeptidase 9 (MMP9) were selected to construct a predictive model. The developed model demonstrated significant efficacy in distinguishing patient prognosis, recurrent cases, and characteristics of high inflammation, hypoxia, and immunosuppression. Furthermore, this model can serve as a valuable tool for guiding the use of trametinib.

Conclusions

In summary, this study provides a comprehensive understanding of the interplay between M2 macrophages and cancer cells in glioma; utilizes a cross-talk gene signature to develop a predictive model that can predict the differentiation of patient prognosis, recurrence instances, and microenvironment characteristics; and aids in optimizing the application of trametinib in glioma patients.

Targeted modulation of myeloid-derived suppressor cells in the tumor microenvironment: Implications for cancer therapy

Myeloid-derived suppressor cells (MDSCs) represent a heterogeneous population of immature myeloid cells originating from the bone marrow, known for their potent immunosuppressive functions that contribute to tumor immune evasion and progression. This paper provides a comprehensive analysis of the multifaceted interactions between MDSCs and tumors, exploring their distinct phenotypes and immunosuppressive mechanisms. Key roles of MDSCs in tumor biology are discussed, including their involvement in the formation of the pre-metastatic niche, facilitation of angiogenesis, enhancement of vascular permeability, suppression of tumor cell apoptosis, and promotion of resistance to cancer therapies. Additionally, the review highlights recent advances in the development of MDSC-targeting therapies, with a focus on their potential to enhance anti-tumor immunity. The therapeutic potential of Traditional Chinese Medicine (TCM) in modulating MDSC quantity and function is also explored, suggesting a novel approach to cancer treatment by integrating traditional and modern therapeutic strategies.

Jiedu recipe, a compound Chinese herbal medicine, suppresses hepatocellular carcinoma metastasis by inhibiting the release of tumor-derived exosomes in a hypoxic microenvironment

OBJECTIVE

Tumor-derived exosomes (TDEs) play crucial roles in intercellular communication. Hypoxia in the tumor microenvironment enhances secretion of TDEs and accelerates tumor metastasis. Jiedu recipe (JR), a traditional Chinese medicinal formula, has demonstrated efficacy in preventing the metastasis of hepatocellular carcinoma (HCC). However, the underlying mechanism remains largely unknown.

METHODS

Animal experiments were performed to investigate the metastasis-preventing effects of JR. Bioinformatics analysis and in vitro assays were conducted to explore the potential targets and active components of JR. TDEs were assessed using nanoparticle tracking analysis (NTA) and Western blotting (WB). Exosomes derived from normoxic or hypoxic HCC cells (H-TDEs) were collected to establish premetastatic mouse models. JR was intragastrically administered to evaluate its metastasis-preventive effects. WB and lysosomal staining were performed to investigate the effects of JR on lysosomal function and autophagy. Bioinformatics analysis, WB, NTA, and immunofluorescence staining were used to identify the active components and potential targets of JR.

RESULTS

JR effectively inhibited subcutaneous-tumor-promoted lung premetastatic niche development and tumor metastasis. It inhibited the release of exosomes from tumor cells under hypoxic condition. JR treatment promoted both lysosomal acidification and suppressed secretory autophagy, which were dysregulated in hypoxic tumor cells. Quercetin was identified as the active component in JR, and the epidermal growth factor receptor (EGFR) was identified as a potential target. Quercetin inhibited EGFR phosphorylation and promoted the nuclear translocation of transcription factor EB (TFEB). Hypoxia-impaired lysosomal function was restored, and secretory autophagy was alleviated by quercetin treatment.

CONCLUSION

JR suppressed HCC metastasis by inhibiting hypoxia-stimulated exosome release, restoring lysosomal function, and suppressing secretory autophagy. Quercetin acted as a key component of JR and regulated TDE release through EGFR-TFEB signaling. Our study provides a potential strategy for retarding tumor metastasis by targeting H-TDE secretion. Please cite this article as: Jia WT, Xiang S, Zhang JB, Yuan JY, Wang YQ, Liang SF, Lin WF, Zhai XF, Shang Y, Ling CQ, Cheng BB. Jiedu recipe, a compound Chinese herbal medicine, suppresses hepatocellular carcinoma metastasis by inhibiting the release of tumor-derived exosomes in a hypoxic microenvironment through the EGFR-TFEB signaling pathway. J Integr Med. 2024; 22(6): 697-709.

Unleashing nanotechnology to redefine tumor-associated macrophage dynamics and non-coding RNA crosstalk in breast cancer

Breast cancer is a significant global health issue. Tumor-associated macrophages (TAMs) are crucial in influencing the tumor microenvironment and the progression of the disease. TAMs exhibit remarkable plasticity in adopting distinct phenotypes ranging from pro-inflammatory and anti-tumorigenic (M1-like) to immunosuppressive and tumor-promoting (M2-like). This review elucidates the multifaceted roles of TAMs in driving breast tumor growth, angiogenesis, invasion, and metastatic dissemination. Significantly, it highlights the intricate crosstalk between TAMs and non-coding RNAs (ncRNAs), including microRNAs, long noncoding RNAs, and circular RNAs, as a crucial regulatory mechanism modulating TAM polarization and functional dynamics that present potential therapeutic targets. Nanotechnology-based strategies are explored as a promising approach to reprogramming TAMs toward an anti-tumor phenotype. Various nanoparticle delivery systems have shown potential for modulating TAM polarization and inhibiting tumor-promoting effects. Notably, nanoparticles can deliver ncRNA therapeutics to TAMs, offering unique opportunities to modulate their polarization and activity.

Profiling hypoxia signaling reveals a lncRNA signature contributing to immunosuppression in high-grade glioma

Background

Hypoxic conditions in glioma are linked to tumor aggressiveness, poor prognosis, and treatment resistance. Long non-coding RNAs (lncRNAs) play key roles in the hypoxic and immune microenvironment of cancers, but their link to hypoxia-induced immunosuppression in high-grade glioma (HGG) is not well-studied.

Methods

Gene expression profiles from TCGA and CGGA, along with clinical and genomic data, were analyzed. Bioinformatics methods including Consensus Clustering, Pearson correlation, and Cox regression analyses were used. Cell proliferation was assessed using cell counting kit-8 and colony formation assays. Glioma-macrophage interactions were evaluated using a co-culture model.

Results

Hypoxia subtype clustering showed hypoxic stress correlates with worse HGG prognosis. Eight hypoxia-related lncRNAs (AP000695.4, OSMR-AS1, AC078883.3, RP11-545E17.3, LINC01057, LINC01503, TP73-AS1, and LINC00672) with prognostic value were identified, forming a risk signature that separated patients into distinct prognostic groups. Multivariate Cox regression confirmed the signature as an independent prognostic factor. High-risk patients had greater hypoxia, leading to an immunosuppressive environment and immunotherapy resistance via tumor-associated macrophages (TAMs). TP73-AS1 significantly influenced hypoxia-induced TAM infiltration and M2 polarization.

Conclusions

We profiled hypoxic stress in HGG and developed an 8-lncRNA hypoxia-related signature predicting patient survival and immunotherapy response, emphasizing its role in hypoxia-induced immunosuppression.

A quartet of cancer stem cell niches in hepatocellular carcinoma

Hepatocellular Carcinoma (HCC), the most prevalent type of primary liver cancer, is known for its aggressive behavior and poor prognosis. The Cancer Stem Cell theory, which postulates the presence of a small population of self-renewing cells called Cancer Stem Cells (CSCs), provides insights into various clinical and molecular features of HCC such as tumor heterogeneity, metabolic adaptability, therapy resistance, and recurrence. These CSCs are nurtured in the tumor microenvironment (TME), where a mix of internal and external factors creates a tumor-supportive niche that is continuously evolving both spatially and temporally, thus enhancing the tumor's complexity. This review details the origins of hepatic CSCs (HCSCs) and the factors influencing their stem-like qualities. It highlights the reciprocal crosstalk between HCSCs and the TME (hypoxic, vascular, invasive, and immune niches), exploring the signaling pathways involved and how these interactions control the malignant traits of CSCs. Additionally, it discusses potential therapeutic approaches targeting the HCSC niche and their possible uses in clinical practice.

Firing up "cold" tumors: Ferroptosis causes immune activation by improving T cell infiltration

Immune checkpoint blocking (ICB), a tumor treatment based on the mechanism of T-cell activation, has shown high efficacy in clinical trials, but not all patients benefit from it. Immune checkpoint inhibitors (ICIs) do not respond to cold tumors that lack effective T-cell infiltration but respond well to hot tumors with sufficient T-cell infiltration. How to convert an unresponsive cold tumor into a responsive hot tumor is an important topic in cancer immunotherapy. Ferroptosis, a newly discovered immunogenic cell death (ICD) form, has great potential in cancer therapy. In the process of deeply understanding the mechanism of cold tumor formation, it was found that ferroptosis showed a powerful immune-activating effect by improving T-cell infiltration, and the combination of ICB therapy significantly enhanced the anti-tumor efficacy. This paper reviews the complex relationship between T cells and ferroptosis, as well as summarizes the various mechanisms by which ferroptosis enhances T cell infiltration: reactivation of T cells and reversal of immunosuppressive tumor microenvironment (TME), as well as recent advances of ICI in combination with targeted ferroptosis therapies, which provides guidance for better improving the ICB efficacy of cold tumors.

A single-cell RNA-seq dataset describing macrophages in NSCLC tumor and peritumor tissues

Examining tumor-associated macrophages in the immune microenvironment of non-small cell lung cancer (NSCLC) is essential for gaining an understanding of the genesis and development of NSCLC as well as for identifying key clinical therapeutic targets. Although previous studies have reported the diverse phenotypes and functions of macrophages in tumor tissues, thereby highlighting their significant role in the tumor microenvironment, the characteristic differences and correlations between tumor and peritumor tissue-derived macrophages that are necessary for an understanding of NSCLC progression remain unclear. Based on single-cell RNA sequencing, we generated a comprehensive dataset of transcriptomes from NSCLC tumor and peritumor tissues, thereby facilitating comprehensive analysis and providing significant insights. In summary, our dataset will serve as a valuable transcriptomic resource for further studies investigating NSCLC development.

Characterization of the Breast Cancer Liver Metastasis Microenvironment via Machine Learning Analysis of the Primary Tumor Microenvironment

Breast cancer liver metastases (BCLM) are hypovascular lesions that resist intravenously administered therapies and have grim prognosis. Immunotherapeutic strategies targeting BCLM critically depend on the tumor microenvironment (TME), including tumor-associated macrophages. However, a priori characterization of the BCLM TME to optimize therapy is challenging because BCLM tissue is rarely collected. In contrast to primary breast tumors for which tissue is usually obtained and histologic analysis performed, biopsies or resections of BCLM are generally discouraged due to potential complications. This study tested the novel hypothesis that BCLM TME characteristics could be inferred from the primary tumor tissue. Matched primary and metastatic human breast cancer samples were analyzed by imaging mass cytometry, identifying 20 shared marker clusters denoting macrophages (CD68, CD163, and CD206), monocytes (CD14), immune response (CD56, CD4, and CD8a), programmed cell death protein 1, PD-L1, tumor tissue (Ki-67 and phosphorylated ERK), cell adhesion (E-cadherin), hypoxia (hypoxia-inducible factor-1α), vascularity (CD31), and extracellular matrix (alpha smooth muscle actin, collagen, and matrix metalloproteinase 9). A machine learning workflow was implemented and trained on primary tumor clusters to classify each metastatic cluster density as being either above or below median values. The proposed approach achieved robust classification of BCLM marker data from matched primary tumor samples (AUROC ≥ 0.75, 95% confidence interval ≥ 0.7, on the validation subsets). Top clusters for prediction included CD68+, E-cad+, CD8a+PD1+, CD206+, and CD163+MMP9+. We conclude that the proposed workflow using primary breast tumor marker data offers the potential to predict BCLM TME characteristics, with the longer term goal to inform personalized immunotherapeutic strategies targeting BCLM.

SIGNIFICANCE

BCLM tissue characterization to optimize immunotherapy is difficult because biopsies or resections are rarely performed. This study shows that a machine learning approach offers the potential to infer BCLM characteristics from the primary tumor tissue.

A new perspective on the therapeutic potential of tumor metastasis: targeting the metabolic interactions between TAMs and tumor cells

Tumor-associated macrophages (TAMs) undergo metabolic reprogramming, encompassing glucose, amino acid, fatty acid metabolism, tricarboxylic acid (TCA) cycle, purine metabolism, and autophagy, within the tumor microenvironment (TME). The metabolic interdependencies between TAMs and tumor cells critically influence macrophage recruitment, differentiation, M2 polarization, and secretion of epithelial-mesenchymal transition (EMT)-related factors, thereby activating intratumoral EMT pathways and enhancing tumor cell invasion and metastasis. Tumor cell metabolic alterations, including hypoxia, metabolite secretion, aerobic metabolism, and autophagy, affect the TME's metabolic landscape, driving macrophage recruitment, differentiation, M2 polarization, and metabolic reprogramming, ultimately facilitating EMT, invasion, and metastasis. Additionally, macrophages can induce tumor cell EMT by reprogramming their aerobic glycolysis. Recent experimental and clinical studies have focused on the metabolic interactions between macrophages and tumor cells to control metastasis and inhibit tumor progression. This review highlights the regulatory role of TAM-tumor cell metabolic codependencies in EMT, offering valuable insights for TAM-targeted therapies in highly metastatic tumors. Modulating the metabolic interplay between tumors and TAMs represents a promising therapeutic strategy for treating patients with metastatic cancers.

Spatial resolved transcriptomics reveals distinct cross-talk between cancer cells and tumor-associated macrophages in intrahepatic cholangiocarcinoma

BACKGROUND

Multiple studies have shown that tumor-associated macrophages (TAMs) promote cancer initiation and progression. However, the reprogramming of macrophages in the tumor microenvironment (TME) and the cross-talk between TAMs and malignant subclones in intrahepatic cholangiocarcinoma (iCCA) has not been fully characterized, especially in a spatially resolved manner. Deciphering the spatial architecture of variable tissue cellular components in iCCA could contribute to the positional context of gene expression containing information pathological changes and cellular variability.

METHODS

Here, we applied spatial transcriptomics (ST) and digital spatial profiler (DSP) technologies with tumor sections from patients with iCCA.

RESULTS

The results reveal that spatial inter- and intra-tumor heterogeneities feature iCCA malignancy, and tumor subclones are mainly driven by physical proximity. Tumor cells with TME components shaped the intra-sectional heterogenetic spatial architecture. Macrophages are the most infiltrated TME component in iCCA. The protein trefoil factor 3 (TFF3) secreted by the malignant subclone can induce macrophages to reprogram to a tumor-promoting state, which in turn contributes to an immune-suppressive environment and boosts tumor progression.

CONCLUSIONS

In conclusion, our description of the iCCA ecosystem in a spatially resolved manner provides novel insights into the spatial features and the immune suppressive landscapes of TME for iCCA.

A Hypoxia-Decidual Macrophage Regulatory Axis in Normal Pregnancy and Spontaneous Miscarriage

The significance of hypoxia at the maternal-fetal interface is proven to be self-explanatory in the context of pregnancy. During the first trimester, low oxygen conditions play a crucial role in processes such as angiogenesis, trophoblast invasion and differentiation, and immune regulation. Recently, there has been increasing research on decidual macrophages, which contribute to the maintenance of immune tolerance, placental and fetal vascular development, and spiral artery remodeling, to investigate the effects of hypoxia on their biological behaviors. On these grounds, this review describes the dynamic changes in oxygen levels at the maternal-fetal interface throughout gestation, summarizing current knowledge on how the hypoxic environment sustains a successful pregnancy by regulating retention, differentiation and efferocytosis of decidual macrophages. Additionally, we explore the relationship between spontaneous miscarriages and an abnormal hypoxia-macrophage axis, shedding light on the underlying mechanisms. However, further studies are essential to elucidate these pathways in greater detail and to develop targeted interventions that could improve pregnancy outcomes.

Metabolic reprogramming and immune evasion: the interplay in the tumor microenvironment

Tumor cells possess complex immune evasion mechanisms to evade immune system attacks, primarily through metabolic reprogramming, which significantly alters the tumor microenvironment (TME) to modulate immune cell functions. When a tumor is sufficiently immunogenic, it can activate cytotoxic T-cells to target and destroy it. However, tumors adapt by manipulating their metabolic pathways, particularly glucose, amino acid, and lipid metabolism, to create an immunosuppressive TME that promotes immune escape. These metabolic alterations impact the function and differentiation of non-tumor cells within the TME, such as inhibiting effector T-cell activity while expanding regulatory T-cells and myeloid-derived suppressor cells. Additionally, these changes lead to an imbalance in cytokine and chemokine secretion, further enhancing the immunosuppressive landscape. Emerging research is increasingly focusing on the regulatory roles of non-tumor cells within the TME, evaluating how their reprogrammed glucose, amino acid, and lipid metabolism influence their functional changes and ultimately aid in tumor immune evasion. Despite our incomplete understanding of the intricate metabolic interactions between tumor and non-tumor cells, the connection between these elements presents significant challenges for cancer immunotherapy. This review highlights the impact of altered glucose, amino acid, and lipid metabolism in the TME on the metabolism and function of non-tumor cells, providing new insights that could facilitate the development of novel cancer immunotherapies.

Immunotherapy and the ovarian cancer microenvironment: Exploring potential strategies for enhanced treatment efficacy

Despite progress in cancer immunotherapy, ovarian cancer (OC) prognosis continues to be disappointing. Recent studies have shed light on how not just tumour cells, but also the complex tumour microenvironment, contribute to this unfavourable outcome of OC immunotherapy. The complexities of the immune microenvironment categorize OC as a 'cold tumour'. Nonetheless, understanding the precise mechanisms through which the microenvironment influences the effectiveness of OC immunotherapy remains an ongoing scientific endeavour. This review primarily aims to dissect the inherent characteristics and behaviours of diverse cells within the immune microenvironment, along with an exploration into its reprogramming and metabolic changes. It is expected that these insights will elucidate the operational dynamics of the immune microenvironment in OC and lay a theoretical groundwork for improving the efficacy of immunotherapy in OC management.

Integrated Analysis of Phagocytic and Immunomodulatory Markers in Cervical Cancer Reveals Constellations of Potential Prognostic Relevance

Despite improvements in vaccination, screening, and treatment, cervical cancer (CC) remains a major healthcare problem on a global scale. The tumor microenvironment (TME) plays an important and controversial role in cancer development, and the mechanism of the tumor's escape from immunological surveillance is still not clearly defined. We aim to investigate the expression of CD68 and CD47 in patients with different histological variants of CC, tumor characteristics, and burden. This is a retrospective cohort study performed on paraffin-embedded tumor tissues from 191 patients diagnosed with CC between 2014 and 2021 at the Medical University Pleven, Bulgaria. Slides for immunohistochemical (IHC) evaluation were obtained, and the expression of CD68 was scored in intratumoral (IT) and stromal (ST) macrophages (CD68+cells) using a three-point scoring scale. The CD47 expression was reported as an H-score. All statistical analyses were performed using R v. 4.3.1 for Windows. Infiltration by CD68-IT cells in the tumor depended on histological type and the expression of CD47. Higher levels of the CD47 H-score were significantly more frequent among patients in the early stage. Higher levels of infiltration by CD68-ST cells were associated with worse prognosis, and the infiltration of CD68-IT cells was associated with reduced risk of death from neoplastic disease. TME is a complex ecosystem that has a major role in the growth and development of tumors. Macrophages are a major component of innate immunity and, when associated with a tumor process, are defined as TAM. Tumor cells try to escape immunological surveillance in three ways, and one of them is reducing immunogenicity by the overexpression of negative coreceptors by T-lymphocytes and their ligands on the surface of tumor cells. One such mechanism is the expression of CD47 in tumor cells, which sends a "don't eat me" signal to the macrophages and, thus, prevents phagocytosis. To our knowledge, this is the first study that has tried to establish the relationship between the CD47 and CD68 expression levels and some clinicopathologic features in CC. We found that the only clinicopathological feature implicating the level of CD68 infiltration was the histological variant of the tumor, and only for CD68-IT-high levels were these observed in SCC. High levels of CD47 expression were seen more frequently in pT1B than pT2A and pT2B in the FIGO I stage than in the FIGO II and III stages. Infiltration by large numbers of CD68-IT cells was much more common among patients with a high expression of CD47 in tumor cells. A high level of infiltration by CD68-ST cells was associated with a worse prognosis, and a high level of infiltration by CD68-ST cells was associated with a lower risk of death from cancer.

Single-nuclei sequencing of uterine serous carcinoma reveals racial differences in immune signaling

Significant racial disparities exist between Black and White patients with uterine serous carcinoma (USC). While the reasons for these disparities are unclear, several studies have demonstrated significantly different rates of driver mutations between racial groups, including TP53. However, limited research has investigated the transcriptional differences of tumors or the composition of the tumor microenvironment (TME) between these groups. Here, we report the single-nuclei RNA-sequencing profiles of primary USC tumors from diverse racial backgrounds. We find that there are significant differences between the tumors of Black and White patients. Tumors from Black patients exhibited higher expression of specific genes associated with aggressiveness, such as PAX8, and axon guidance and synaptic signaling pathways. We also demonstrated that T cell populations are reduced in the tumor tissue compared to matched benign, while anti-inflammatory macrophage populations are retained within the TME. Furthermore, we investigated the connection between PAX8 overexpression and immunosuppression in USC through regulation of several cytokines and chemokines. Notably, we show that PAX8 activity can influence macrophage gene expression and protein secretion. These studies provide a detailed understanding of the USC transcriptome and TME, and identify differences in tumor biology from patients of different racial backgrounds.

The Effects of Hypoxia on the Immune-Metabolic Interplay in Liver Cancer

M2-like macrophages promote tumor growth and cancer immune evasion. This study used an in vitro model to investigate how hypoxia and tumor metabolism affect macrophage polarization. Liver cancer cells (HepG2 and VX2) and macrophages (THP1) were cultured under hypoxic (0.1% O2) and normoxic (21% O2) conditions with varying glucose levels (2 g/L or 4.5 g/L). Viability assays and extracellular pH (pHe) measurements were conducted over 96 hours. Macrophages were exposed to the tumor-conditioned medium (TCM) from the cancer cells, and polarization was assessed using arginase and nitrite assays. GC-MS-based metabolic profiling quantified TCM meta-bolites and correlated them with M2 polarization. The results showed that pHe in TCMs decreased more under hypoxia than normoxia (p < 0.0001), independent of glucose levels. The arginase assay showed hypoxia significantly induced the M2 polarization of macrophages (control group: p = 0.0120,0.1%VX2-TCM group: p = 0.0149, 0.1%HepG2-TCM group: p < 0.0001, 0.1%VX2-TCMHG group: p = 0.0001, and 0.1%HepG2-TCMHG group: p < 0.0001). TCMs also induced M2 polarization under normoxic conditions, but the strongest M2 polarization occurred when both tumor cells and macrophages were incubated under hypoxia with high glucose levels. Metabolomics revealed that several metabolites, particularly lactate, were correlated with hypoxia and M2 polarization. Under normoxia, elevated 2-amino-butanoic acid (2A-BA) strongly correlated with M2 polarization. These findings suggest that targeting tumor hypoxia could mitigate immune evasion in liver tumors. Lactate drives acidity in hypoxic tumors, while 2A-BA could be a therapeutic target for overcoming immunosuppression in normoxic conditions.