N1 versus N2 and PMN-MDSC: A critical appraisal of current concepts on tumor-associated neutrophils and new directions for human oncology

TRAIL induces cytokine production via the NFkB2 pathway promoting neutrophil chemotaxis and neutrophil-mediated immune-suppression in triple negative breast cancer cells

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a potential cancer therapeutic that induces apoptosis in cancer cells while sparing the non-malignant cells in preclinical models. However, its efficacy in clinical trials has been limited, suggesting unknown mechanisms modulating TRAIL activity in patients. We hypothesized that TRAIL treatment elicits transcriptional changes in triple negative breast cancer (TNBC) cells that alter the immune milieu. RNAseq analysis of MDA-MB-231 cells along with validation in additional cell lines demonstrated that TRAIL induced cytokines such as CXCLs 1, 2, 3, 8,11 and IL-6, which are known to modify neutrophil function. Mechanistically, TRAIL dependent induction of the cytokines was predominantly mediated by death receptor 5, caspase-8 and the non-canonical NFKB2 pathway. These cytokines produced by TRAIL-treated TNBC cells enhanced chemotaxis of normal human donor isolated neutrophils. Using TNBC xenograft models, TRAIL induced activation of NFkB2 pathway, cytokine production and increased neutrophil recruitment into the tumors. Moreover, preincubation of neutrophils in supernatants from TRAIL-treated TNBC cells significantly impaired neutrophil function as measured by reduced respiratory burst and cytotoxic effect against TNBC cells. Transcriptomic analysis of neutrophils incubated with either TRAIL alone or supernatant of TRAIL-treated TNBC cells revealed increased expression of inflammatory cytokines, immune modulatory genes, immune checkpoint genes, and genes implicated in delayed neutrophil apoptosis. Functional studies showed that these neutrophils suppress T cell proliferation and augment Treg suppressive phenotype. Collectively, our study demonstrates a novel role of TRAIL-induced NFKB2-dependent cytokine production that promotes neutrophil chemotaxis and neutrophil-mediated immune suppression.

MYO1F in neutrophils is required for the response to immune checkpoint blockade therapy

Tumor-associated neutrophils (TANs) represent a significant barrier to the effectiveness of immune checkpoint blockade (ICB) therapy. A comprehensive understanding of TANs' regulatory mechanisms is therefore essential for predicting ICB efficacy and improving immunotherapy strategies. Our study reveals that MYO1F is selectively downregulated in neutrophils within both human cancers and murine tumor models, showing a negative correlation with ICB response. Mechanistically, MYO1F normally inhibits neutrophil immunosuppression and proliferation by restraining STAT3 activity. However, during tumorigenesis, tumor-derived TGF-β1 disrupts the binding of SPI1 to intron 8 of Myo1f via DNA methylation, thereby suppressing Myo1f transcription. The resultant decrease in MYO1F reprograms neutrophils into an immunosuppressive state through the STAT3-dependent signaling pathways. This immunosuppressive state further contributes to tumor microenvironment (TME) remodeling by inducing CTL exhaustion. These findings establish MYO1F as a critical regulator within TANs, highlighting its significant role in modulating ICB therapy efficacy.

Tumor cells that resist neutrophil anticancer cytotoxicity acquire a prometastatic and innate immune escape phenotype

In the tumor host, neutrophils may exhibit protumor or antitumor activity. It is hypothesized that in response to host-derived or therapy-induced factors, neutrophils adopt diverse functional states to ultimately execute these differential functions. Here, we provide an alternative scenario in which the response of an individual tumor cell population determines the overall protumor versus antitumor outcome of neutrophil‒tumor interactions. Experimentally, we show that human neutrophils, which are sequentially stimulated with bacteria and secreted factors from tumor cells, kill a certain proportion of tumor target cells. However, the majority of the tumor cells remained resistant to this neutrophil-mediated killing and underwent a functional, phenotypic and transcriptomic switch that was reminiscent of partial epithelial‒to-mesenchymal transition. This cell biological switch was associated with physical escape from NK-mediated killing and resulted in enhanced metastasis to the lymph nodes in a preclinical orthotopic mouse model. Mechanistically, we identified the antimicrobial neutrophil granule proteins neutrophil elastase (NE) and matrix metalloprotease-9 (MMP-9) as the molecular mediators of this functional switch. We validated these data in patients with head and neck cancer and identified bacterially colonized intratumoral niches that were enriched for mesenchymal tumor cells and neutrophils expressing NE and MMP-9. Our data reveal the parallel execution of tumor cytotoxic and prometastatic activity by activated neutrophils and identify NE and MMP-9 as mediators of lymph node metastasis. The identified mechanism explains the functional dichotomy of tumor-associated neutrophils at the level of the tumor target cell response and has implications for superinfected cancers and the dysbiotic tumor microenvironment.

Geranyl hydroquinone alleviates rheumatoid arthritis-associated pain by suppressing neutrophil accumulation, N1 polarization and ROS production in mice

Pain hypersensitivity is a hallmark of rheumatoid arthritis (RA); however, the underlying mechanisms and effective therapies remain largely undefined. Emerging studies suggest that neutrophils play a significant role in the pathology of RA, yet their involvement in RA-associated pain is still unclear. The present study investigates whether neutrophil activity contributes to pain pathogenesis in RA. Our flow cytometry analysis reveals that the accumulation and N1 polarization (indicated by the ratio of CD45+CD66b+CD95+ subset) of neutrophils occur in synovial fluid samples from RA patients, positively correlating with pain scores. In the collagen-induced rheumatoid arthritis (CIA) model, mice demonstrate neutrophil accumulation, N1 polarization (indicated by the ratio of CD45+Ly-6G+CD95+ subset), and reactive oxygen species (ROS) production in affected paw tissues. Geranyl hydroquinone (GHQ), a natural meroterpenoid with antioxidative properties, reverses N1 polarization and ROS production in synovial neutrophils from RA patients in vitro. Moreover, a 10-day oral administration of GHQ alleviates pain hypersensitivity and reduces neutrophil accumulation, N1 polarization, and ROS production in CIA mice. Notably, GHQ treatment reverses TNF-α-evoked ROS production in neutrophils in vitro through downregulating gene expression associated with the ROS pathway. Further, liquid chromatography-tandem mass spectrometry and biochemical analyses indicate that GHQ binds to microsomal glutathione S-transferase 3 (MGST3) in neutrophils. In vitro and in vivo evidence demonstrates that the RA-specific analgesic and antioxidative effects of GHQ require MGST3. Lastly, GHQ administration exhibits superior therapeutic effects compared to methotrexate, a first-line disease-modifying antirheumatic drug, in CIA mice. Collectively, our findings indicate that neutrophil accumulation, N1 polarization and ROS production contribute to RA-associated pain, suggesting that targeting these pathways, such as with GHQ, could be a viable strategy for RA treatment.

Role of Neutrophils in Anti-Tumor Activity: Characteristics and Mechanisms of Action

As one of the leading components in the immune system, neutrophils in the tumor microenvironment (TME) have received considerable attention in recent years. The tumor-killing effects of neutrophils in a variety of tumors have been reported. However, the functions of neutrophils in tumors remain to be completely elucidated, and both anti-tumor and tumor-promotion activities have been reported. This review focuses on the characteristics of neutrophils and their mechanisms of action in the TME, with an emphasis on their anti-tumor activity, including reactive oxygen species (ROS)-induced tumor killing, cytotoxic T lymphocytes (CTLs)-induced tumor killing, trogocytosis, cytotoxic enzymes, and trained immunity. Furthermore, the possible targets and methods of tumor treatment regimens for neutrophils are explored, with the aim of exploring the use of neutrophils in the future as a potential anti-tumor treatment strategy.

Natural killer cells: the immune frontline against circulating tumor cells

Natural killer (NK) play a key role in controlling tumor dissemination by mediating cytotoxicity towards cancer cells without the need of education. These cells are pivotal in eliminating circulating tumor cells (CTCs) from the bloodstream, thus limiting cancer spread and metastasis. However, aggressive CTCs can evade NK cell surveillance, facilitating tumor growth at distant sites. In this review, we first discuss the biology of NK cells, focusing on their functions within the tumor microenvironment (TME), the lymphatic system, and circulation. We then examine the immune evasion mechanisms employed by cancer cells to inhibit NK cell activity, including the upregulation of inhibitory receptors. Finally, we explore the clinical implications of monitoring circulating biomarkers, such as NK cells and CTCs, for therapeutic decision-making and emphasize the need to enhance NK cell-based therapies by overcoming immune escape mechanisms.

Large-scale bulk and single-cell RNA sequencing combined with machine learning reveals glioblastoma-associated neutrophil heterogeneity and establishes a VEGFA+ neutrophil prognostic model

BACKGROUND

Neutrophils play a key role in the tumor microenvironment (TME); however, their functions in glioblastoma (GBM) are overlooked and insufficiently studied. A detailed analysis of GBM-associated neutrophil (GBMAN) subpopulations may offer new insights and opportunities for GBM immunotherapy.

METHODS

We analyzed single-cell RNA sequencing (scRNA-seq) data from 127 isocitrate dehydrogenase (IDH) wild-type GBM samples to characterize the GBMAN subgroups, emphasizing developmental trajectories, cellular communication, and transcriptional networks. We implemented 117 machine learning combinations to develop a novel risk model and compared its performance to existing glioma models. Furthermore, we assessed the biological and molecular features of the GBMAN subgroups in patients.

RESULTS

From integrated large-scale scRNA-seq data (498,747 cells), we identified 5,032 neutrophils and classified them into four distinct subtypes. VEGFA+GBMAN exhibited reduced inflammatory response characteristics and a tendency to interact with stromal cells. Furthermore, these subpopulations exhibited significant differences in transcriptional regulation. We also developed a risk model termed the "VEGFA+neutrophil-related signature" (VNRS) using machine learning methods. The VNRS model showed higher accuracy than previously published risk models and was an independent prognostic factor. Additionally, we observed significant differences in immunotherapy responses, TME interactions, and chemotherapy efficacy between high-risk and low-risk VNRS score groups.

CONCLUSION

Our study highlights the critical role of neutrophils in the TME of GBM, allowing for a better understanding of the composition and characteristics of GBMAN. The developed VNRS model serves as an effective tool for evaluating the risk and guiding clinical treatment strategies for GBM.

CLINICAL TRIAL NUMBER

Not applicable.

Targeting S100A8/A9-NCF1 axis in tumor microenvironment to prevent tumor metastasis by self-assembled peptide nanofibers

The immunosuppressive microenvironment plays a crucial role in driving and accelerating tumor metastasis. S100A8/A9, produced by myeloid-derived suppressor cells, is a potential therapeutic target for metastatic cancer due to its role in promoting premetastatic niche formation. Previous studies have revealed that the S100A9-targeted peptide (H6, MEWSLEKGYTIK) fused to the Fc region of mouse IgG2b antibodies exhibits antitumor effects; however, the mechanism remains unclear. Here, dual-function peptide nanofibers (H6-Q11) were constructed, consisting of peptide H6 and self-assembly peptide (Q11, QQKFQFQFEQQ), which achieved high avidity for S100A9. In vivo studies showed that H6-Q11 nanofibers significantly prolonged lung retention and inhibited pulmonary metastasis from melanoma and breast cancer without obvious toxicity. Immunological analyses indicated that treatment with H6-Q11 nanofibers decreased the infiltration of immunosuppressive cells while promoting the recruitment of immune effector cells to the lungs, potentially correlated with disturbances of S100A8/A9-NCF1 signaling in the tumor microenvironment. Our findings support a potential clinical application of S100A9-targeted peptide nanofibers as candidate nanomedicine for inhibiting tumor metastasis.

Tumor‑associated neutrophils: Critical regulators in cancer progression and therapeutic resistance (Review)

Cancer is the second leading cause of death among humans worldwide. Despite remarkable improvements in cancer therapies, drug resistance remains a significant challenge. The tumor microenvironment (TME) is intimately associated with therapeutic resistance. Tumor‑associated neutrophils (TANs) are a crucial component of the TME, which, along with other immune cells, play a role in tumorigenesis, development and metastasis. In the current review, the roles of TANs in the TME, as well as the mechanisms of neutrophil‑mediated resistance to cancer therapy, including immunotherapy, chemotherapy, radiotherapy and targeted therapy, were summarized. Furthermore, strategies for neutrophil therapy were discussed and TANs were explored as potential targets for cancer treatment. In conclusion, the need to explore the precise roles, recruitment pathways and mechanisms of action of TANs was highlighted for the purpose of developing therapies that precisely target TANs and reverse drug resistance.

Prognostic significance of cytotoxic-T-lymphocytes to immunosuppressive lymphocytes ratio (CIL) in laryngeal squamous cell carcinoma

Immunoscore (IS), based on CD3/CD8, has been proposed to characterize the immune landscape of the tumor immune microenvironment and has demonstrated an association with the prognosis of laryngeal squamous cell carcinoma (LSCC). However, traditional IS does not include immunosuppressive cells. The purpose of this study is to evaluate the prognostic performance of cytotoxic-T-lymphocytes to immunosuppressive cells ratio (CIL) in laryngeal squamous cell carcinoma (LSCC) patients. Two cohorts were included in this study: The training cohort (N = 75) consisted of tumor tissue microarrays from LSCC patients in our department, and the validation cohort (N = 116) utilized bulk RNA-seq data from the TCGA database. Patients with high IS or CIL showed significantly prolonged overall survival and disease-free survival in both cohorts. Upon analyzing the relative contribution of each parameter, it was found that CIL exhibited the highest significance among the factors examined. It emerged as the strongest predictor of overall survival, emphasizing its crucial influence in determining the outcomes. The prognostic ability of IS-TCGA was similar to the original IS. Additionally, high CILM2-TCGA was associated with prolonged survival of patients with LSCC in the TCGA dataset. CIL, which is easier to construct than IS, proves to be reliable in predicting survival outcomes for patients with LSCC.

A comprehensive review on targeting diverse immune cells for anticancer therapy: Beyond immune checkpoint inhibitors

Although immune checkpoint inhibitors (ICIs) have revolutionized cancer treatment, primary resistance and acquired resistance continue to limit their efficacy for many patients. To address resistance and enhance the anti-tumor activity within the tumor immune microenvironment (TIME), numerous therapeutic strategies targeting both innate and adaptive immune cells have emerged. These include combination therapies with ICIs, chimeric antigen receptor T-cell (CAR-T), chimeric antigen receptor macrophages (CAR-Ms) or chimeric antigen receptor natural killer cell (CAR-NK) therapy, colony stimulating factor 1 receptor (CSF1R) inhibitors, dendritic cell (DC) vaccines, toll-like receptor (TLR) agonists, cytokine therapies, and chemokine inhibition. These approaches underscore the significant potential of the TIME in cancer treatment. This article provides a comprehensive and up-to-date review of the mechanisms of action of various innate and adaptive immune cells within the TIME, as well as the therapeutic strategies targeting each immune cell type, aiming to deepen the understanding of their therapeutic potential.

Exploring Neutrophil Heterogeneity and Plasticity in Health and Disease

Neutrophils, the most abundant polymorphonuclear leukocytes, are critical first responders to infection, and have historically been underappreciated in terms of their functional complexity within the immune response. Once viewed primarily as short-lived, innate immune cells with limited functional plasticity, recent research has illuminated their considerable heterogeneity and diverse functional roles, which extend beyond their involvement in steady-state immunity. This review seeks to provide an updated analysis of neutrophil development, maturation, heterogeneity, and plasticity, with a focus on how these characteristics influence immune modulation in both healthy and diseased tissues. Beginning with the origin of neutrophils, we explore their maturation into effector cells and their evolving roles in immune defense under homeostatic and disease-associated conditions. We then delve into their heterogeneity, discussing recent breakthroughs in neutrophil research that challenge the traditional view of neutrophils as a uniform population. We address the significant advances that have been made in identifying distinct neutrophil subsets, the emerging complexities of their plasticity, and the challenges that remain in fully understanding their functional diversity. Finally, we highlight future directions and opportunities for continued exploration in this rapidly advancing field, shedding light on how these insights could open new avenues for therapeutic interventions.

Efficacy Assessment and Prognostic Value of Inflammatory Markers in Patients with Stage IV Acral and Cutaneous Melanoma Receiving PD-1 Inhibitors

Background

Malignant melanoma (MM) is a highly aggressive cancer. Different subtypes have different sensitivities to immunotherapy and lack peripheral blood markers. Few studies have examined the role of inflammatory markers in predicting the overall survival (OS) in stage IV acral melanoma (AM) and cutaneous melanoma (CM) patients receiving immunotherapy.

Purpose

This study aimed to investigate the value of inflammatory markers in efficacy and prognosis for stage IV melanoma patients who underwent immunotherapy.

Patients and Methods

This multicenter study reviewed the clinicopathological characteristics and inflammatory markers of 94 stage IV AM and CM patients receiving PD-1 inhibitors therapy. Pearson's chi-squared test or Fisher's exact test was used to compare baseline characteristics. The optimal cut-off values for these markers were stratified using time-dependent receiver operating characteristic curves (t-ROC). Kaplan-Meier (KM) curves and Log rank test were used to explore the relationship between inflammatory markers and survival outcomes. Cox regression analysis was performed to screen for independent prognostic factors and a nomogram was constructed. The model ability was tested by the C-index, t-ROC, calibration curves, and decision curve analysis curves.

Results

High NLR level was significantly correlated with lymph node metastasis and 3 or above metastatic sites (P=0.009, P=0.012). High PNI level favored a better ECOG PS (P=0.023). According to the KM curves, patients with baseline NLR>2.37, PNI<=42.65, and RLR>11.08 had worse OS (P<0.001, P<0.001, P<0.001). Cox regression analysis based on P<0.05 showed that M1c/M1d (P<0.001), NLR (P=0.003), and PNI (P<0.001) were significantly correlated with OS, and were visualized in a nomogram. C-index, t-ROC, area under the curve (AUC), and calibration curves revealed promising discrimination and accuracy of the nomogram. Decision curve analysis curves showed good clinical utility.

Conclusion

We established a prognostic predictive model based on distant metastatic sites, NLR, and PNI, and verified its superior performance and potential for clinical application.

IL-8 contributes to functional diversity of tumor-infiltrating neutrophils: A new target for cancer immunotherapy

In this issue of Developmental Cell, Tang et al. identify CD74high neutrophils as a subpopulation promoted by IL-8 in the tumor microenvironment of non-small lung cancer (NSCLC). These CD74high neutrophils support anti-tumor T cell responses and enhance the efficacy of anti-PD-1 immunotherapy and targeted therapy in NSCLC.

Glucose Metabolism Reprogramming of Immune Cells in the Microenvironment of Pancreatic and Hepatobiliary Cancers

BACKGROUND AND AIM

Pancreatic and hepatobiliary cancers are increasing in prevalence and contribute significantly to cancer-related mortality worldwide. Emerging therapeutic approaches, particularly immunotherapy, are gaining attention for their potential to harness the patient's immune system to combat these tumors. Understanding the role of immune cells in the tumor microenvironment (TME) and their metabolic reprogramming is key to developing more effective treatment strategies. This review aims to explore the relationship between immune cell function and glucose metabolism in the TME of pancreatic and hepatobiliary cancers.

METHODS

This review synthesizes current research on the metabolic adaptations of immune cells, specifically focusing on glucose metabolism within the TME of pancreatic and hepatobiliary cancers. We examine the mechanisms by which immune cells influence tumor progression through metabolic reprogramming and how these interactions can be targeted for therapeutic purposes.

RESULTS

Immune cells in the TME undergo significant metabolic changes, with glucose metabolism playing a central role in modulating immune responses. These metabolic shifts not only affect immune cell function but also influence tumor behavior and progression. The unique metabolic features of immune cells in pancreatic and hepatobiliary cancers provide new opportunities for targeting immune responses to combat these malignancies more effectively.

CONCLUSION

Understanding the complex relationship between immune cell glucose metabolism and tumor progression in the TME of pancreatic and hepatobiliary cancers offers promising therapeutic strategies. By modulating immune responses through targeted metabolic interventions, it may be possible to improve the efficacy of immunotherapies and better combat these aggressive cancers.

Neutrophil heterogeneity and plasticity: unveiling the multifaceted roles in health and disease

Neutrophils, the most abundant circulating leukocytes, have long been recognized as key players in innate immunity and inflammation. However, recent discoveries unveil their remarkable heterogeneity and plasticity, challenging the traditional view of neutrophils as a homogeneous population with a limited functional repertoire. Advances in single-cell technologies and functional assays have revealed distinct neutrophil subsets with diverse phenotypes and functions and their ability to adapt to microenvironmental cues. This review provides a comprehensive overview of the multidimensional landscape of neutrophil heterogeneity, discussing the various axes along which diversity manifests, including maturation state, density, surface marker expression, and functional polarization. We highlight the molecular mechanisms underpinning neutrophil plasticity, focusing on the complex interplay of signaling pathways, transcriptional regulators, and epigenetic modifications that shape neutrophil responses. Furthermore, we explore the implications of neutrophil heterogeneity and plasticity in physiological processes and pathological conditions, including host defense, inflammation, tissue repair, and cancer. By integrating insights from cutting-edge research, this review aims to provide a framework for understanding the multifaceted roles of neutrophils and their potential as therapeutic targets in a wide range of diseases.

Neutrophils: From Inflammatory Bowel Disease to Colitis-Associated Colorectal Cancer

Inflammatory bowel disease (IBD) is a non-specific inflammatory disease of digestive tract, primarily manifesting as ulcerative colitis (UC) and Crohn's disease (CD). The precise etiology of IBD remains elusive. The interplay of genetic factors, environmental influences, and intestinal microbiota contributes to the establishment of an uncontrolled immune environment within the intestine, which can progressively lead to atypical hyperplasia and ultimately to malignancy over a long period. This colorectal malignant tumor that arises from chronic IBD is referred to as colitis-associated colorectal cancer (CAC). Dysregulation in the quantity and functionality of neutrophils plays a significant role in the onset, progression, and recurrence of IBD, as well as in the transition from IBD to CAC. Neutrophils affect the pathophysiology of IBD through various mechanisms, including the production of reactive oxygen species (ROS), degranulation, the release of inflammatory mediators and chemokines, and the formation of neutrophil extracellular traps (NETs). These processes can induce DNA mutations, thereby facilitating the development of colon cancer. Given the incomplete understanding of the disease mechanisms underlying IBD and CAC, effective treatment and prevention strategies remain challenging. Consequently, a comprehensive review of the functional roles of neutrophils in IBD and CAC is essential for advancing our understanding of IBD pathogenesis and identifying potential therapeutic targets.

The heterogeneity of neutrophils in cancer and its implication for therapeutic targeting

Neutrophils have a pivotal role in safeguarding the host against pathogens and facilitating tissue remodeling. They possess a large array of tools essential for executing these functions. Neutrophils have a critical role in cancer, where they are largely associated with negative clinical outcome and resistance to therapy. However, the specific role of neutrophils in cancer is complex and controversial, owing to their high functional diversity and acute sensitivity to the microenvironment. In this Perspective, we discuss the accumulated evidence that suggests that the functional diversity of neutrophils can be ascribed to two principal functional states, each with distinct characteristics: classically activated neutrophils and pathologically activated immunosuppressive myeloid-derived suppressor cells. We discuss how the antimicrobial factors in neutrophils can contribute to tumor progression and the fundamental mechanisms that govern the pathologically activated myeloid-derived suppressor cells. These functional states play divergent roles in cancer and thus require separate consideration in therapeutic targeting.

Effect of neutrophils on tumor immunity and immunotherapy resistance with underlying mechanisms

Neutrophils are key mediators of the immune response and play essential roles in the development of tumors and immune evasion. Emerging studies indicate that neutrophils also play a critical role in the immunotherapy resistance in cancer. In this review, firstly, we summarize the novel classification and phenotypes of neutrophils and describe the regulatory relationships between neutrophils and tumor metabolism, flora microecology, neuroendocrine and tumor therapy from a new perspective. Secondly, we review the mechanisms by which neutrophils affect drug resistance in tumor immunotherapy from the aspects of the immune microenvironment, tumor antigens, and epigenetics. Finally, we propose several promising strategies for overcoming tumor immunotherapy resistance by targeting neutrophils and provide new research ideas in this area.

Neutrophil and Colorectal Cancer

Colorectal cancer (CRC) is often associated with metastasis and recurrence and is the leading cause of cancer-related mortality. In the progression of CRC, recent studies have highlighted the critical role of neutrophils, particularly tumor-associated neutrophils (TANs). TANs have both tumor-promoting and tumor-suppressing activities, contributing to metastasis, immunosuppression, angiogenesis, and epithelial-to-mesenchymal transition. Tumor-promoting TANs promote tumor growth by releasing proteases, reactive oxygen species, and cytokines, whereas tumor-suppressing TANs enhance immune responses by activating T cells and natural killer cells. Understanding the mechanisms underlying TAN mobilization, plasticity, and their role in the tumor microenvironment has revealed potential therapeutic targets. This review provides a comprehensive overview of TAN biology in CRC and discusses both the tumor-promoting and tumor-suppressing functions of neutrophils. Novel therapeutic approaches targeting TANs, such as chemokine receptor antagonists, aim to modulate neutrophil reprogramming and offer promising avenues for improving treatment outcomes of CRC.

Cryoablation-induced neutrophil Ca2+ elevation and NET formation exacerbate immune escape in colorectal cancer liver metastasis

BACKGROUND

Liver metastasis poses a significant barrier to effective immunotherapy in patients with colorectal cancer. Cryoablation has emerged as a vital supplementary therapeutic approach for these patients. However, its impact on the tumor microenvironment following the ablation of liver metastases remains unclear.

METHODS

We acquired multi-omics time-series data at 1 day, 5 days, and 14 days post-cryoablation, based on tumor and peripheral blood samples from clinical patients, cell co-culture models, and a liver metastases mouse model built on the MC38 cell line in C57BL/6 J mice. This dataset included single-cell transcriptomic sequencing, bulk tissue transcriptomic sequencing, 4D-Label-Free proteomics, flow cytometry data, western blot data, and histological immunofluorescence staining of pathological specimens.

RESULTS

We found that a neutrophil-related inflammatory state persisted for at least 14 days post-cryoablation. During this period, neutrophils underwent phenotypic changes, shifting from the N1 to the N2 type. Cryoablation also caused a significant increase in intracellular Ca2+ concentration in neutrophils, which triggered the formation of PAD4-dependent neutrophil extracellular traps (NETs), further promoting immune evasion. Moreover, animal studies demonstrated that depleting or inhibiting the CXCL2-CXCR2 signaling axis within neutrophils, or degrading NETs, could effectively restore the host's anti-tumor immune response.

CONCLUSIONS

These findings underscore the critical role of neutrophils and their NETs in immune escape following cryoablation. Targeting the CXCL2-CXCR2-Ca2+-PAD4 axis could enhance the therapeutic response to PD-1 antibodies, providing a potential strategy to improve treatment outcomes for colorectal cancer with liver metastases.

BioTextQuest v2.0: An evolved tool for biomedical literature mining and concept discovery

The process of navigating through the landscape of biomedical literature and performing searches or combining them with bioinformatics analyses can be daunting, considering the exponential growth of scientific corpora and the plethora of tools designed to mine PubMed(®) and related repositories. Herein, we present BioTextQuest v2.0, a tool for biomedical literature mining. BioTextQuest v2.0 is an open-source online web portal for document clustering based on sets of selected biomedical terms, offering efficient management of information derived from PubMed abstracts. Employing established machine learning algorithms, the tool facilitates document clustering while allowing users to customize the analysis by selecting terms of interest. BioTextQuest v2.0 streamlines the process of uncovering valuable insights from biomedical research articles, serving as an agent that connects the identification of key terms like genes/proteins, diseases, chemicals, Gene Ontology (GO) terms, functions, and others through named entity recognition, and their application in biological research. Instead of manually sifting through articles, researchers can enter their PubMed-like query and receive extracted information in two user-friendly formats, tables and word clouds, simplifying the comprehension of key findings. The latest update of BioTextQuest leverages the EXTRACT named entity recognition tagger, enhancing its ability to pinpoint various biological entities within text. BioTextQuest v2.0 acts as a research assistant, significantly reducing the time and effort required for researchers to identify and present relevant information from the biomedical literature.

The ketogenic diet modulates tumor-associated neutrophil polarization via the AMOT-YAP/TAZ axis to inhibit colorectal cancer progression

Despite significant advances in the diagnosis and treatment of colorectal cancer (CRC), the prognosis for late-stage patients remains poor, highlighting the urgent need for new preventive and therapeutic strategies. Recent studies have focused on the ketogenic diet (KD) and its metabolite, β-hydroxybutyrate (BHB), for their tumor-suppressive effects and modulation of inflammatory responses. Using the azoxymethane (AOM) / dextran sulfate sodium (DSS)-induced mouse CRC model, we found that the ketogenic diet and BHB inhibit pro-tumor N2-type tumor-associated neutrophils (TANs) while promoting the polarization of TANs towards the anti-tumor N1 type. This shift in TANs polarization affects tumor growth and metastasis. The underlying mechanism involves BHB acting on the intracellular receptor histone deacetylases 3 (HDAC3), which modulates the activation of the AMOT-YAP/TAZ axis, leading to the inhibition of pro-carcinogenic factor transcription and release. Moreover, clinical cohort data corroborate these findings, showing that CRC patients with elevated BHB levels have significantly lower rates of lymph node involvement, which is associated with a higher infiltration ratio of anti-carcinogenic N1-type TANs in the tumor microenvironment (TME). These results suggest that BHB levels could serve as a prognostic biomarker for CRC. In conclusion, our findings indicate that BHB derived from KD regulates TANs polarization in CRC via the HDAC3-AMOT-YAP/TAZ axis, effectively inhibiting tumor growth and metastasis. These insights establish a novel theoretical basis for employing the KD in the treatment of CRC and for developing cancer adjuvant immunotherapy strategy based on the polarization of neutrophils.

Exploring the relationship between ulcerative colitis, colorectal cancer, and prostate cancer

Chronic systemic inflammation caused by diseases such as ulcerative colitis (UC) and Crohn's disease (CD) increases the risk of developing colorectal cancer (CRC). Recent evidence indicates that patients with UC are more susceptible to prostate cancer (PCa), and individuals with PCa may also be at a higher risk of developing CRC. However, these relationships are not well defined. A better understanding of this phenomenon could improve the identification of high-risk populations. In this study, we characterized these relationships with experiments using preclinical mouse models of dextran sulfate sodium (DSS)-induced colitis (DSS-UC) and DSS/azoxymethane (AOM)-induced CRC (DSS/AOM-CRC) in wild-type and conditional transgenic mice of PCa. We showed that DSS-induced UC was more severe in mice with PCa and resulted in the development of CRC in the absence of AOM. We further showed that PCa-free mice that developed DSS-induced UC also showed histological changes in the normal prostate that resembled proliferative inflammatory atrophy. Finally, we used immunohistochemical immune profiling to show that mice with PCa-induced chronic systemic inflammation accumulated Gr1+ myeloid cells in the normal colon and exposure to DSS further enriched these cells in active colitis regions and colon tumors. Our study provides evidence to support a link between systemic chronic inflammation and cancer.

Consensus, debate, and prospective on pancreatic cancer treatments

Pancreatic cancer remains one of the most aggressive solid tumors. As a systemic disease, despite the improvement of multi-modality treatment strategies, the prognosis of pancreatic cancer was not improved dramatically. For resectable or borderline resectable patients, the surgical strategy centered on improving R0 resection rate is consensus; however, the role of neoadjuvant therapy in resectable patients and the optimal neoadjuvant therapy of chemotherapy with or without radiotherapy in borderline resectable patients were debated. Postoperative adjuvant chemotherapy of gemcitabine/capecitabine or mFOLFIRINOX is recommended regardless of the margin status. Chemotherapy as the first-line treatment strategy for advanced or metastatic patients included FOLFIRINOX, gemcitabine/nab-paclitaxel, or NALIRIFOX regimens whereas 5-FU plus liposomal irinotecan was the only standard of care second-line therapy. Immunotherapy is an innovative therapy although anti-PD-1 antibody is currently the only agent approved by for MSI-H, dMMR, or TMB-high solid tumors, which represent a very small subset of pancreatic cancers. Combination strategies to increase the immunogenicity and to overcome the immunosuppressive tumor microenvironment may sensitize pancreatic cancer to immunotherapy. Targeted therapies represented by PARP and KRAS inhibitors are also under investigation, showing benefits in improving progression-free survival and objective response rate. This review discusses the current treatment modalities and highlights innovative therapies for pancreatic cancer.

Significance of Immune and Non-Immune Cell Stroma as a Microenvironment of Hepatocellular Carcinoma-From Inflammation to Hepatocellular Carcinoma Progression

Hepatocellular carcinoma (HCC) is the most common liver cancer as well as the most prevalent cause of death in the adult patient population with cirrhosis. The occurrence of HCC is primarily caused by chronic liver inflammation that might occur because of a viral infection, non-alcoholic fatty liver disease (NAFLD), or various lifestyle-associated factors. The objective of this review was to summarize the current knowledge regarding the microenvironment of HCC, indicating how immune- and non-immune-cell stroma might affect the onset and progression of HCC. Therefore, in the following narrative review, we described the role of tumor-infiltrating neutrophils, bone-marrow-derived cells, tumor-associated mast cells, cancer-associated fibroblasts, tumor-associated macrophages, liver-sinusoidal endothelial cells, lymphocytes, and certain cytokines in liver inflammation and the further progression to HCC. A better understanding of the HCC microenvironment might be crucial to introducing novel treatment strategies or combined therapies that could lead to more effective clinical outcomes.

TRAIL-induced cytokine production via NFKB2 pathway promotes neutrophil chemotaxis and immune suppression in triple negative breast cancers

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a potential cancer therapeutic that induces apoptosis in cancer cells while sparing the non-malignant cells in preclinical models. However, its efficacy in clinical trials has been limited, suggesting unknown modulatory mechanisms responsible for the lack of TRAIL activity in patients. Here, we hypothesized that TRAIL treatment elicits transcriptional changes in triple negative breast cancer (TNBC) cells that alter the immune milieu. To test this, we performed an RNAseq analysis of MDA-MB-231 cells treated with TRAIL, followed by validation in additional TNBC cell lines. TRAIL significantly induces expression of multiple cytokines such as CXCLs 1, 2, 3, 8,11 and IL-6, which are known to modify neutrophil function. Mechanistically, the induction of these cytokines was predominantly mediated by death receptor 5, caspase 8 (but not caspase 8 enzymatic activity), and the non-canonical NFKB2 pathway. The cytokines produced by the TRAIL-treated TNBC cells enhanced chemotaxis of healthy human donor isolated neutrophils. In vivo , TRAIL treated TNBC murine xenograft tumors showed activation of the NFKB2 pathway, elevated production of CXCLs and IL-6, and increased neutrophil recruitment into the tumors. Moreover, donor isolated neutrophils preincubated in supernatants from TRAIL-treated TNBC cells exhibited impaired cytotoxic effect against TNBC cells. Transcriptomic analysis of neutrophils incubated with either TRAIL alone or supernatant of TRAIL-treated TNBC cells revealed increased expression of inflammatory cytokines, immune modulatory genes, immune checkpoint genes, and genes implicated in delayed neutrophil apoptosis. Functional studies with these neutrophils confirmed their suppressive effect on T cell proliferation and an increase in Treg suppressive phenotype. Collectively, our study demonstrates a novel role of TRAIL-induced NFKB2-dependent cytokine production that promotes neutrophil chemotaxis and immune suppression.

Cancer stem cells: advances in knowledge and implications for cancer therapy

Cancer stem cells (CSCs), a small subset of cells in tumors that are characterized by self-renewal and continuous proliferation, lead to tumorigenesis, metastasis, and maintain tumor heterogeneity. Cancer continues to be a significant global disease burden. In the past, surgery, radiotherapy, and chemotherapy were the main cancer treatments. The technology of cancer treatments continues to develop and advance, and the emergence of targeted therapy, and immunotherapy provides more options for patients to a certain extent. However, the limitations of efficacy and treatment resistance are still inevitable. Our review begins with a brief introduction of the historical discoveries, original hypotheses, and pathways that regulate CSCs, such as WNT/β-Catenin, hedgehog, Notch, NF-κB, JAK/STAT, TGF-β, PI3K/AKT, PPAR pathway, and their crosstalk. We focus on the role of CSCs in various therapeutic outcomes and resistance, including how the treatments affect the content of CSCs and the alteration of related molecules, CSCs-mediated therapeutic resistance, and the clinical value of targeting CSCs in patients with refractory, progressed or advanced tumors. In summary, CSCs affect therapeutic efficacy, and the treatment method of targeting CSCs is still difficult to determine. Clarifying regulatory mechanisms and targeting biomarkers of CSCs is currently the mainstream idea.

Mechanisms underlying neutrophils adhesion to triple-negative breast cancer cells via CD11b-ICAM1 in promoting breast cancer progression

BACKGROUND

Triple-negative breast cancer (TNBC) is recognized as the most aggressive and immunologically infiltrated subtype of breast cancer. A high circulating neutrophil-to-lymphocyte ratio (NLR) is strongly linked to a poor prognosis among patients with breast cancer, emphasizing the critical role of neutrophils. Although the involvement of neutrophils in tumor metastasis is well documented, their interactions with primary tumors and tumor cells are not yet fully understood.

METHODS

Clinical data were analyzed to investigate the role of neutrophils in breast cancer. In vivo mouse model and in vitro co-culture system were used for mechanism researches. Blocking experiments were further performed to identify therapeutic agents against TNBC.

RESULTS

TNBC cells secreted GM-CSF to sustain the survival of mature neutrophils and upregulated CD11b expression. Through CD11b, neutrophils specifically binded to ICAM1 on TNBC cells, facilitating adhesion. Transcriptomic sequencing combined with human and murine functional experiments revealed that neutrophils, through direct CD11b-ICAM1 interactions, activated the MAPK signaling pathway in TNBC cells, thereby enhancing tumor cell invasion and migration. Atorvastatin effectively inhibited ICAM1 expression in tumor cells, and tumor cells with ICAM1 knockout or treated with atorvastatin were unresponsive to neutrophil activation. The MAPK pathway and MMP9 expression were significantly inhibited in the tumor tissues of TNBC patients treated with atorvastatin.

CONCLUSIONS

Targeting CD11b-ICAM1 with atorvastatin represented a potential clinical approach to reduce the malignant characteristics of TNBC.

Tumour Microenvironment: The General Principles of Pathogenesis and Implications in Diffuse Large B Cell Lymphoma

Diffuse large B cell lymphoma (DLBCL) is the most common type of non-Hodgkin lymphoma worldwide, constituting around 30-40% of all cases. Almost 60% of patients develop relapse of refractory DLBCL. Among the reasons for the therapy failure, tumour microenvironment (TME) components could be involved, including tumour-associated macrophages (TAMs), myeloid-derived suppressor cells (MDSCs), tumour-associated neutrophils (TANs), cancer-associated fibroblasts (CAFs), and different subtypes of cytotoxic CD8+ cells and T regulatory cells, which show complex interactions with tumour cells. Understanding of the TME can provide new therapeutic options for patients with DLBCL and improve their prognosis and overall survival. This review provides essentials of the latest understanding of tumour microenvironment elements and discusses their role in tumour progression and immune suppression mechanisms which result in poor prognosis for patients with DLBCL. In addition, we point out important markers for the diagnostic purposes and highlight novel therapeutic targets.

A novel blood-based epigenetic biosignature in first-episode schizophrenia patients through automated machine learning

Schizophrenia (SCZ) is a chronic, severe, and complex psychiatric disorder that affects all aspects of personal functioning. While SCZ has a very strong biological component, there are still no objective diagnostic tests. Lately, special attention has been given to epigenetic biomarkers in SCZ. In this study, we introduce a three-step, automated machine learning (AutoML)-based, data-driven, biomarker discovery pipeline approach, using genome-wide DNA methylation datasets and laboratory validation, to deliver a highly performing, blood-based epigenetic biosignature of diagnostic clinical value in SCZ. Publicly available blood methylomes from SCZ patients and healthy individuals were analyzed via AutoML, to identify SCZ-specific biomarkers. The methylation of the identified genes was then analyzed by targeted qMSP assays in blood gDNA of 30 first-episode drug-naïve SCZ patients and 30 healthy controls (CTRL). Finally, AutoML was used to produce an optimized disease-specific biosignature based on patient methylation data combined with demographics. AutoML identified a SCZ-specific set of novel gene methylation biomarkers including IGF2BP1, CENPI, and PSME4. Functional analysis investigated correlations with SCZ pathology. Methylation levels of IGF2BP1 and PSME4, but not CENPI were found to differ, IGF2BP1 being higher and PSME4 lower in the SCZ group as compared to the CTRL group. Additional AutoML classification analysis of our experimental patient data led to a five-feature biosignature including all three genes, as well as age and sex, that discriminated SCZ patients from healthy individuals [AUC 0.755 (0.636, 0.862) and average precision 0.758 (0.690, 0.825)]. In conclusion, this three-step pipeline enabled the discovery of three novel genes and an epigenetic biosignature bearing potential value as promising SCZ blood-based diagnostics.

Neutrophils in glioma microenvironment: from immune function to immunotherapy

Glioma is a malignant tumor of the central nervous system (CNS). Currently, effective treatment options for gliomas are still lacking. Neutrophils, as an important member of the tumor microenvironment (TME), are widely distributed in circulation. Recently, the discovery of cranial-meningeal channels and intracranial lymphatic vessels has provided new insights into the origins of neutrophils in the CNS. Neutrophils in the brain may originate more from the skull and adjacent vertebral bone marrow. They cross the blood-brain barrier (BBB) under the action of chemokines and enter the brain parenchyma, subsequently migrating to the glioma TME and undergoing phenotypic changes upon contact with tumor cells. Under glycolytic metabolism model, neutrophils show complex and dual functions in different stages of cancer progression, including participation in the malignant progression, immune suppression, and anti-tumor effects of gliomas. Additionally, neutrophils in the TME interact with other immune cells, playing a crucial role in cancer immunotherapy. Targeting neutrophils may be a novel generation of immunotherapy and improve the efficacy of cancer treatments. This article reviews the molecular mechanisms of neutrophils infiltrating the central nervous system from the external environment, detailing the origin, functions, classifications, and targeted therapies of neutrophils in the context of glioma.

AIRE is expressed in breast cancer TANs and TAMs to regulate the extrinsic apoptotic pathway and inflammation

The autoimmune regulator (AIRE) is a transcriptional regulator expressed in the thymus and is necessary for maintaining immunological self-tolerance. Extrathymic AIRE expression is rare, and a role for AIRE in tumor-associated innate immune cells has not yet been established. In this study, we show that AIRE is expressed in human pro-tumor neutrophils. In breast cancer, AIRE was primarily located to tumor-associated neutrophils (TANs), and to a lesser extent to tumor-associated macrophages (TAMs) and tumor cells. Expression of AIRE in TAN/TAMs, but not in cancer cells, was associated with an adverse prognosis. We show that the functional role for AIRE in neutrophils and macrophages is to regulate expression of immune mediators and the extrinsic apoptotic pathway involving the Fas/TNFR death receptors and cathepsin G. Here, we propose that the role for AIRE in TAN/TAMs in breast tumors is to regulate cell death and inflammation, thus promoting tumor progression.

How murine neutrophils are hijacked within the microenvironment of pancreatic cancer

Discoveries made in the past decades have brought out that, in addition to their classical primary defensive functions against infections, polymorphonuclear neutrophils play key effector roles not only in chronic inflammatory and immune-mediated diseases but also in cancer. In addition, depending on their differentiation/activation status and/or on the physiological or pathological microenvironment in which they reside, neutrophils have been shown to behave as highly plastic cells, able to acquire new phenotypes/functional states. All these features are well manifested in cancer and modulated during tumor progression. Herein, we discuss intriguing data by Lai Ng's group that have shed light on the origin and development of terminally differentiated, proangiogenic, tumor-associated neutrophils, facilitating tumor growth in a murine orthotopic model of pancreatic ductal adenocarcinoma. These findings help to progress toward the ambitious goal of selectively targeting only the skewed pathological neutrophil populations present within the tumor microenvironment.

A novel tumor-associated neutrophil gene signature for predicting prognosis, tumor immune microenvironment, and therapeutic response in breast cancer

Tumor-associated neutrophils (TANs) can promote tumor progression. This study aimed to investigate the molecular signature that predict the prognosis and immune response of breast cancer (BRCA) based on TAN-related gene (TANRG) expression data. The RNA-seq data of BRCA were gathered from The Cancer Genome Atlas (TCGA) and gene expression omnibus (GEO) datasets. Univariate Cox regression analysis and the least absolute shrinkage and selection operator for selecting prognostic genes. A neo-TAN-related risk signature was constructed by multivariate Cox regression analysis. Time-dependent receiver operating characteristic (ROC) curve analyses and Kaplan-Meier analyses were performed to validate the signature in GEO cohorts and the triple-negative breast cancer (TNBC) subtype. We constructed an independent prognostic factor model with 11 TANRGs. The areas under the ROC curve (AUCs) of the TCGA training cohorts for 3-, 5-, and 7-year overall survival were 0.72, 0.73, and 0.73, respectively. The AUCs of the GEO test cohorts for 3-, 5-, and 7-year overall survival were 0.83, 0.89, and 0.94 (GSE25066) and 0.67, 0.69, and 0.73 (GSE58812), respectively. The proportion of immune subtypes differed among the different risk groups. The IC50 values differed significantly between risk groups and can be used as a guide for systemic therapy. The prognostic model developed by TANRGs has excellent predictive performance in BRCA patients. In addition, this feature is closely related to the prediction of survival, immune activity and treatment response in BRCA patients.

Targeting neutrophils: Mechanism and advances in cancer therapy

BACKGROUND

Cancer is a thorny problem which cannot be conquered by mankind at present and recent researchers have put their focus on tumor microenviroment. Neutrophils, the prominent leukocytes in peripheral blood that accumulate in tumours, serves as frontline cells in response to tumour progression owing to the rapid development of micro biotechnology. Hence, targeted therapy with these neutrophils has made targeting treatment a promising field in cancer therapy.

MAIN BODY

We broadly summarise some studies on the phenotypes and functions of tumour-associated neutrophils as well as the unique web-like products of neutrophils that play a role in cancer progression-neutrophil extracellular traps-and the interactions between neutrophils and the tumour microenvironment. Moreover, several targeted neutrophils therapeutic studies have made some progress and provided potential strategies for the treatment of cancer.

CONCLUSION

This review aims to offer a holistic perspective on therapeutic interventions targeting neutrophils to further inspire more researches on cancer therapies.

Mononuclear myeloid cells can shape neutrophils in brain tumors

In most human solid cancer types, a high frequency of intratumoral neutrophils is associated with poor prognosis. In a recent study, Maas et al. identified an intratumoral niche in which mononuclear myeloid cells drive proinflammatory neutrophil activation in brain tumors. This study sheds new light on the intratumoral modulation of neutrophils.

Myeloid-derived suppressor cells in cancer and cancer therapy

Anticancer agents continue to dominate the list of newly approved drugs, approximately half of which are immunotherapies. This trend illustrates the considerable promise of cancer treatments that modulate the immune system. However, the immune system is complex and dynamic, and can have both tumour-suppressive and tumour-promoting effects. Understanding the full range of immune modulation in cancer is crucial to identifying more effective treatment strategies. Myeloid-derived suppressor cells (MDSCs) are a heterogeneous population of myeloid cells that develop in association with chronic inflammation, which is a hallmark of cancer. Indeed, MDSCs accumulate in the tumour microenvironment, where they strongly inhibit anticancer functions of T cells and natural killer cells and exert a variety of other tumour-promoting effects. Emerging evidence indicates that MDSCs also contribute to resistance to cancer treatments, particularly immunotherapies. Conversely, treatment approaches designed to eliminate cancer cells can have important additional effects on MDSC function, which can be either positive or negative. In this Review, we discuss the interplay between MDSCs and various other cell types found in tumours as well as the mechanisms by which MDSCs promote tumour progression. We also discuss the relevance and implications of MDSCs for cancer therapy.

Integrins in Health and Disease-Suitable Targets for Treatment?

Integrin receptors are heterodimeric surface receptors that play multiple roles regarding cell-cell communication, signaling, and migration. The four members of the β2 integrin subfamily are composed of an alternative α (CD11a-d) subunit, which determines the specific receptor properties, and a constant β (CD18) subunit. This review aims to present insight into the multiple immunological roles of integrin receptors, with a focus on β2 integrins that are specifically expressed by leukocytes. The pathophysiological role of β2 integrins is confirmed by the drastic phenotype of patients suffering from leukocyte adhesion deficiencies, most often resulting in severe recurrent infections and, at the same time, a predisposition for autoimmune diseases. So far, studies on the role of β2 integrins in vivo employed mice with a constitutive knockout of all β2 integrins or either family member, respectively, which complicated the differentiation between the direct and indirect effects of β2 integrin deficiency for distinct cell types. The recent generation and characterization of transgenic mice with a cell-type-specific knockdown of β2 integrins by our group has enabled the dissection of cell-specific roles of β2 integrins. Further, integrin receptors have been recognized as target receptors for the treatment of inflammatory diseases as well as tumor therapy. However, whereas both agonistic and antagonistic agents yielded beneficial effects in animal models, the success of clinical trials was limited in most cases and was associated with unwanted side effects. This unfavorable outcome is most probably related to the systemic effects of the used compounds on all leukocytes, thereby emphasizing the need to develop formulations that target distinct types of leukocytes to modulate β2 integrin activity for therapeutic applications.

NETosis: Sculpting tumor metastasis and immunotherapy

The process of neutrophil extracellular traps (NETs) formation, called NETosis, is a peculiar death modality of neutrophils, which was first observed as an immune response against bacterial infection. However, recent work has revealed the unique biology of NETosis in facilitating tumor metastatic process. Neutrophil extracellular traps released by the tumor microenvironment (TME) shield tumor cells from cytotoxic immunity, leading to impaired tumor clearance. Besides, tumor cells tapped by NETs enable to travel through vessels and subsequently seed distant organs. Targeted ablation of NETosis has been proven to be beneficial in potentiating the efficacy of cancer immunotherapy in the metastatic settings. This review outlines the impact of NETosis at almost all stages of tumor metastasis. Furthermore, understanding the multifaceted interplay between NETosis and the TME components is crucial for supporting the rational development of highly effective combination immunotherapeutic strategies with anti-NETosis for patients with metastatic disease.

Stimuli-responsive nanodelivery systems for amplifying immunogenic cell death in cancer immunotherapy

Immunogenic cell death (ICD) is a special pattern of tumor cell death, enabling to elicit tumor-specific immune response via the release of damage-associated molecular patterns and tumor-associated antigens in the tumor microenvironment. ICD-induced immunotherapy holds the promise for completely eliminating tumors and long-term protective antitumor immune response. Increasing ICD inducers have been discovered for boosting antitumor immunity via evoking ICD. Nonetheless, the utilization of ICD inducers remains insufficient owing to serious toxic reactions, low localization efficiency within the tumor microenvironmental niche, etc. For overcoming such limitations, stimuli-responsive multifunctional nanoparticles or nanocomposites with ICD inducers have been developed for improving immunotherapeutic efficiency via lowering toxicity, which represent a prospective scheme for fostering the utilization of ICD inducers in immunotherapy. This review outlines the advances in near-infrared (NIR)-, pH-, redox-, pH- and redox-, or NIR- and tumor microenvironment-responsive nanodelivery systems for ICD induction. Furthermore, we discuss their clinical translational potential. The progress of stimuli-responsive nanoparticles in clinical settings depends upon the development of biologically safer drugs tailored to patient needs. Moreover, an in-depth comprehending of ICD biomarkers, immunosuppressive microenvironment, and ICD inducers may accelerate the advance in smarter multifunctional nanodelivery systems to further amplify ICD.

Functional immunophenotyping of blood neutrophils identifies novel endotypes of viral response in preschool children with recurrent wheezing

BACKGROUND

Preschool children with recurrent wheezing are heterogeneous, with differing responses to respiratory viral infections. Although neutrophils are crucial for host defense, their function has not been studied in this population.

OBJECTIVE

We performed functional immunophenotyping on isolated blood neutrophils from 52 preschool children with recurrent wheezing (aeroallergen sensitization, n = 16; no sensitization, n = 36).

METHODS

Blood neutrophils were purified and cultured overnight with polyinosinic:polycytidylic acid [poly(I:C)] as a viral analog stimulus. Neutrophils underwent next-generation sequencing with Reactome pathway analysis and were analyzed for cytokine secretion, apoptosis, myeloperoxidase, and extracellular DNA release. CD14+ monocytes were also exposed to neutrophil culture supernatant and analyzed for markers of M1 and M2 activation.

RESULTS

A total of 495 genes, related largely to the innate immune system and neutrophil degranulation, were differently expressed in children with versus without aeroallergen sensitization. Functional experiments identified more neutrophil degranulation and extracellular trap formation (ie, more myeloperoxidase and extracellular DNA) and less neutrophil proinflammatory cytokine secretion in children with aeroallergen sensitization. Neutrophils also shifted CD14+ monocytes to a more anti-inflammatory (ie, M2) phenotype in sensitized children and a more proinflammatory (ie, M1) phenotype in nonsensitized children. Although both groups experienced viral exacerbations, annualized exacerbation rates prompting unscheduled health care were also higher in children without aeroallergen sensitization after enrollment.

CONCLUSIONS

Systemic neutrophil responses to viral infection differ by allergic phenotype and may be less effective in preschool children without allergic inflammation. Further studies of neutrophil function are needed in this population, which often has less favorable therapeutic responses to inhaled corticosteroids and other therapies directed at type 2-high inflammation.

Exploiting innate immunity for cancer immunotherapy

Immunotherapies have revolutionized the treatment paradigms of various types of cancers. However, most of these immunomodulatory strategies focus on harnessing adaptive immunity, mainly by inhibiting immunosuppressive signaling with immune checkpoint blockade, or enhancing immunostimulatory signaling with bispecific T cell engager and chimeric antigen receptor (CAR)-T cell. Although these agents have already achieved great success, only a tiny percentage of patients could benefit from immunotherapies. Actually, immunotherapy efficacy is determined by multiple components in the tumor microenvironment beyond adaptive immunity. Cells from the innate arm of the immune system, such as macrophages, dendritic cells, myeloid-derived suppressor cells, neutrophils, natural killer cells, and unconventional T cells, also participate in cancer immune evasion and surveillance. Considering that the innate arm is the cornerstone of the antitumor immune response, utilizing innate immunity provides potential therapeutic options for cancer control. Up to now, strategies exploiting innate immunity, such as agonists of stimulator of interferon genes, CAR-macrophage or -natural killer cell therapies, metabolic regulators, and novel immune checkpoint blockade, have exhibited potent antitumor activities in preclinical and clinical studies. Here, we summarize the latest insights into the potential roles of innate cells in antitumor immunity and discuss the advances in innate arm-targeted therapeutic strategies.

A novel neutrophil extracellular traps-related lncRNA signature predicts prognosis in patients with early-stage lung adenocarcinoma

BACKGROUND

Neutrophil extracellular traps (NETs) could entrap tumour cells and promote their dissemination and metastasis. Further analysis of NETs-related molecules is expected to provide a new strategy for prognosis prediction and treatment of lung adenocarcinoma (LUAD) patients.

METHODS

The model construction was established through co-expression analysis, Lasso Cox regression, univariate and multivariate COX regression, Gene ontology and Kyoto Encyclopedia of Genes and Genomes pathway. The potential drugs and analysed drug sensitivity were screened by pRRophetic packages.

RESULTS

In this study, we constructed a 15 NETs-related long non-coding RNAs (lncRNAs) prognostic prediction model (AC091057.1, SPART-AS1, AC023796.2, AL031600.2, AC084781.1, AC032011.1, FAM66C, C026355.2, AL096870.2, AC092718.5, PELATON, AC008635.1, AL162632.3, AC087501.4 and AC123768.3) for patients with early-stage LUAD based on public databases and datasets. The signature is associated with immune cell functions, tumour mutation burden and treatment sensitivity in LUAD patients. Additionally, we found that FAM66C is highly expressed in lung cancer patients for the first time, which is associated with poor prognosis. FAM66C knockdown significantly inhibited the proliferation and migration ability of the tumour cells.

CONCLUSIONS

In conclusion, this model is a new and effective prognostic and efficacy predictive biomarker, FAM66C plays an oncogene role in the process of LUAD development. It may provide a new theoretical basis for the clinical diagnosis and treatment in LUAD patients in early stage.

Chitinase 3-like-1 Expression in the Microenvironment Is Associated with Neutrophil Infiltration in Bladder Cancer

Bladder cancer is a common cancer with well-established therapeutic strategies. However, recurrence occurs in 50% of patients with non-muscle-invasive bladder cancer, and 20% of patients progress to muscle-invasive bladder cancer. The 5-year survival rate for muscle-invasive bladder cancer patients is disappointingly low, ranging from 36% to 48%. A molecular marker of interest is chitinase 3-like-1 (CHI3L1), which is elevated in various cancers, including bladder cancer. In addition to its role in cancer cells, CHI3L1 also has regulatory abilities in immune cells. Neutrophil infiltration has been shown to positively correlate with overall survival, progression-free survival, and relapse-free survival in bladder cancer patients. However, the relationship between CHI3L1 and neutrophils remain poorly understood. Therefore, this study investigated the relationship between CHI3L1 level and protumor neutrophil infiltration in bladder cancer. We analyzed the GSE128959 dataset and the data of a bladder cancer cohort undergoing chemotherapy. We observed higher expression of CHI3L1 in bladder cancer patients with invasive or chemotherapy-resistance. Our results revealed a positive correlation between CHI3L1 expression and protumor neutrophil infiltration. Elevated CHI3L1 expression was associated with genes which were related to the recruitment and infiltration of neutrophils. Consequently, CHI3L1 may serve as a novel evaluation factor for the degree of neutrophil infiltration in advanced bladder cancer in those scheduled for chemotherapy.

Detection of myeloid-derived suppressor cells by flow cytometry

Recently discovered heterogeneous myeloid-derived suppressor cells (MDSCs) are some of the most discussed immunosuppressive cells in contemporary immunology, especially in the tumor microenvironment, and are defined primarily by their T cell immunosuppressive function. The importance of these cells extend to other chronic pathological conditions as well, including chronic infection, inflammation, and tissue remodeling. In many of these conditions, their accumulation/expansion correlates with disease progression, poor prognosis, and reduced survival, which highlights the potential of how these cells may be used in a clinical setting as both prognostic factor and therapeutic target. In healthy individuals, these cells are usually not present in the circulation. Therefore, monitoring this cell population is of potential clinical significance, and utility in basic research. However, these cells have a complex phenotype without one single marker of sufficient specificity for their identification. Flow cytometry is a powerful tool allowing multi-parameter analysis of heterogeneous cell populations, which makes it ideally suitable for the complex phenotypic analysis essential for identification and enumeration of circulating MDSCs. This approach has the potential to provide a novel clinically useful tool for assessment of prognosis and treatment outcomes. The protocol in this chapter describes a flow cytometric analysis to identify and quantify MDSCs from human or mouse whole blood leukocytes and peripheral blood mononuclear cells, as well as a single cell suspension from solid tissue, by using multicolor fluorescence-conjugated antibodies against their surface markers.