NETosis: Sculpting tumor metastasis and immunotherapy

Neutrophil extracellular traps and reactive oxygen species: Predictors of prognosis in bladder cancer

Neutrophils, the most abundant leukocytes in circulation, have become the subject of intensive research due to growing evidence of their role as modulators of cancer with both anti- and pro-tumorigenic effects. However, their prognostic function related to the release of neutrophil extracellular traps (NETs) and production of reactive oxygen species (ROS) has not yet been elucidated in the context of bladder cancer (BC). This study aimed to evaluate the ability of circulating neutrophils from BC patients to undergo NETosis and produce ROS-both spontaneously and following activation with phorbol 12-myristate 13-acetate (PMA)-using flow cytometry and immunofluorescence techniques. Their relevance to clinicopathological characteristics was also evaluated. Our results showed that PMA-treated neutrophils had increased early NETosis in patients with stage II (P = 0.048) and T2 (P = 0.014) compared to those with stage III and T3, respectively. These cells also showed a significant increase in ROS production in patients with T2 compared to those with T3 (P = 0.026) and T4 (P = 0.014), as well as in patients with stage II compared to stage IV (P = 0.048). Additionally, spontaneous ROS production was higher in patients without lymphovascular invasion than in those with invasion (P = 0.013). The increased activity of neutrophils observed in earlier stages (stage II and T2) suggests a potential protective mechanism in the early phases of cancer progression. It also highlights NETosis and ROS production by neutrophils as possible biomarkers for assessing disease progression. These findings provide insights into the complex interactions of neutrophils within the tumor microenvironment and lay the groundwork for further investigations into targeted therapies, potentially improving prognostic evaluations and treatment outcomes for patients.

Lipotoxicity, lipid peroxidation and ferroptosis: a dilemma in cancer therapy

The vulnerability of tumor cells to lipid peroxidation, driven by redox imbalance and lipid overabundance within the tumor microenvironment (TME), has become a focal point for novel antitumor strategies. Ferroptosis, a form of regulated cell death predicated on lipid peroxidation, is emerging as a promising approach. Beyond their role in directly eliminating tumor cells, lipid peroxidation and its products, such as 4-hydroxynonenal (HNE), exert an additional influence by damaging DNA and shaping an environment conducive to tumor growth and metastasis. This process polarizes macrophages towards a pro-inflammatory phenotype, dampens the antigen-presenting capacity of dendritic cells (DCs), and undermines the cytotoxic functions of T and NK cells. Furthermore, it transforms neutrophils into pro-tumorigenic polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs). The lipid peroxidation of stroma cells also contributes to tumor progression. Although advanced nanotherapies have shown the ability to target tumor cells precisely, they often overlook the nuanced effects of lipid peroxidation products. In this review, we highlight a synergistic mechanism in which lipid peroxidation products and ferroptosis contribute to an immunosuppressive state that is temporally distinct from cell death. This insight broadens our understanding of ferroptosis-derived immunosuppression, encompassing all types of immune cells within the TME. This review aims to catalyze further research in this underexplored area, emphasizing the potential of lipid peroxidation products to hinder the clinical translation of ferroptosis-based therapies.

Targeting neutrophil extracellular traps in cancer progression and metastasis

Neutrophils serve as pivotal effectors and regulators of the intricate immune system. Their contributions are indispensable, encompassing the obliteration of pathogens and a significant role in both cancer initiation and progression. Conversely, malignancies profoundly affect neutrophil activity, maturation, and lifespans. Cancer cells manipulate their biology to enhance or suppress the key functions of neutrophils. This manipulation is one of the most remarkable defensive mechanisms used by neutrophils, including the formation of neutrophil extracellular traps (NETs). NETs are filamentous structures comprising DNA, histones, and proteins derived from cytotoxic granules. In this review, we discuss the bidirectional interplay in which cancer elicits NET formation, and NETs concurrently facilitate cancer progression. Here, we discuss how vascular dysfunction and thrombosis induced by neutrophils and NETs contribute to an elevated risk of mortality from cardiovascular complications in patients with cancer. Ultimately, we propose a series of therapeutic strategies that hold promise for effectively targeting NETs in clinical settings.

Corticosteroid-Dependent Association between Prognostic Peripheral Blood Cell-Free DNA Levels and Neutrophil-Mediated NETosis in Patients with Glioblastoma

PURPOSE

Noninvasive prognostic biomarkers to inform clinical decision-making are an urgent unmet need for the management of patients with glioblastoma (GBM). We previously showed that higher circulating cell-free DNA (ccfDNA) concentration is associated with worse survival in GBM. However, the biology underlying this is unknown.

EXPERIMENTAL DESIGN

We prospectively enrolled 129 patients with treatment-naïve GBM with blood drawn prior to initial resection (baseline) and at the time of the first postradiotherapy MRI. We performed ccfDNA methylation deconvolution to determine cellular sources of ccfDNA. ELISA was performed to detect citrullinated histone 3 (citH3), a marker of neutrophil extracellular traps (NET). Multiplex proteomic analysis was used to measure soluble inflammatory proteins.

RESULTS

We found that neutrophils contributed the highest proportion of prognostic ccfDNA. The percentage of ccfDNA derived from neutrophils was correlated with total [ccfDNA] but only in patients receiving preoperative corticosteroids. At baseline and on therapy, [citH3] was significantly higher in the plasma of patients with GBM receiving corticosteroids compared with corticosteroid-naïve GBM or no-cancer controls. Unsupervised hierarchical clustering of ccfDNA methylation patterns yielded two clusters, with one enriched for patients with the NETosis phenotype and who received corticosteroids. Unsupervised clustering of circulating inflammatory proteins yielded similar results.

CONCLUSIONS

These data suggest neutrophil-mediated NETosis is the dominant source of prognostic ccfDNA in patients with GBM and may be associated with glucocorticoid exposure. If further studies show that pharmacological inhibition of NETosis can mitigate the deleterious effects of corticosteroids, these plasma markers will have important clinical utility as noninvasive correlative biomarkers.

Metabolism-Related Programmed Cell Death: Unveiling Prognostic Biomarkers, Immune Checkpoints, and Therapeutic Strategies in Ovarian Cancer

BACKGROUND

Ovarian cancer (OC), the gynecologic malignancy with the poorest prognosis, is driven by metabolic reprogramming and dysregulated programmed cell death (PCD). However, their interplay and prognostic significance remain inadequately understood.

METHODS

Transcriptomic data from OC patients and healthy controls (TCGA and GTEx) were analyzed to identify differentially expressed genes (DEGs) intersecting with metabolism-related (MRGs) and PCD-related genes (PCDRGs). Prognostic genes were determined using univariate Cox regression, LASSO, multivariate Cox regression, and stepwise analyses. Consensus clustering revealed enrichment differences, while a risk model and nomogram were developed for outcome prediction. Associations between prognostic genes, immune microenvironment, and drug sensitivity were also assessed.

RESULTS

A total of 166 candidate genes were identified, with PLA2G2D, LPCAT3, ARG1, PLA2G4A, and EXOSC3 emerging as significant prognostic markers. The risk model demonstrated marked survival differences, while the nomogram showed robust calibration for survival prediction. Differential immune cell infiltration was observed between risk groups. Additionally, Sinularin and Fulvestrant exhibited variable sensitivity, validated through molecular docking models.

CONCLUSION

Metabolism-related PCD genes were identified as pivotal prognostic markers in OC, providing critical insights for prognostic evaluation and targeted therapy development.

Interactions between ferroptosis and tumour development mechanisms: Implications for gynaecological cancer therapy (Review)

Ferroptosis is a form of programmed cell death that is distinct from apoptosis. The mechanism involves redox‑active metallic iron and is characterized by an abnormal increase in iron‑dependent lipid reactive oxygen species, which results in high levels of membrane lipid peroxides. The relationship between ferroptosis and gynaecological tumours is complex. Ferroptosis can regulate tumour proliferation, metastasis and chemotherapy resistance, and targeting ferroptosis is a promising antitumour approach. Ferroptosis interacts with mechanisms related to tumorigenesis and development, such as macrophage polarization, the neutrophil trap network, mitochondrial autophagy and cuproptosis. The present review examines recent information on the interaction between the molecular mechanism of ferroptosis and other tumour‑related mechanisms, as well as the involvement of ferroptosis in gynaecological tumours, to identify implications for gynaecological cancer therapy.

Identification of the shared gene signatures in retinoblastoma and osteosarcoma by machine learning

Osteosarcoma (OS) is the most prevalent secondary sarcoma associated with retinoblastoma (RB). However, the molecular mechanisms driving the interactions between these two diseases remain incompletely understood. This study aims to explore the transcriptomic commonalities and molecular pathways shared by RB and OS, and to identify biomarkers that predict OS prognosis effectively. RNA sequences and patient information for OS and RB were obtained from the University of California Santa Cruz (UCSC) Xena and Gene Expression Omnibus databases. When RB and OS were first identified, a common gene expression profile was discovered. Weighted Gene Co-expression Network Analysis (WGCNA) revealed co-expression networks associated with OS after immunotyping patients. To evaluate the genes shared by RB and OS, univariate and multivariate Cox regression analysis were then carried out. Three machine learning methods were used to pick key genes, and risk models were created and verified. Next, medications that target independent prognostic genes were found using the Cellminer database. The comparison of differential gene expression between OS and RB revealed 1216 genes, primarily linked to the activation and proliferation of immune cells. WGCNA identified 12 modules related to OS immunotyping, with the grey module showing a strong correlation with the immune-inflamed phenotype. This module intersected with differential genes from RB, producing 65 RB-associated OS Immune-inflamed Genes (ROIGs). Analysis identified 6 hub genes for model construction through univariate Cox regression and three machine learning techniques. A risk model based on these hub genes was established, demonstrating significant prognostic value for OS. Genes shared between OS and RB contribute to the progression of both cancers through multiple pathways. The ROIGs risk score model independently predicts the overall survival of OS patients. Additionally, this study highlights genes with potential as therapeutic targets or biomarkers for clinical use.

HSYA ameliorates venous thromboembolism by depleting the formation of TLR4/NF-κB pathway-dependent neutrophil extracellular traps

Neutrophil extracellular traps (NETs), released by activated neutrophils, are implicated in various medical conditions, including venous thromboembolism (VTE). To develop effective therapeutic strategies for VTE, it is crucial to elucidate the mechanisms involved. In this study, we explored the role of NETs in VTE pathogenesis and assessed the impact of hydroxyl safflower yellow pigment A (HSYA) treatment on VTE pathogenesis. Various biochemical, pharmacological, and functional assessments were performed in human samples and VTE mouse models. Our findings revealed that NETs formation was enhanced in VTE patients and mouse model. NETs were shown to reduce the viability and integrity of endothelial cells and facilitated ferroptosis in human umbilical vein endothelial cells (HUVECs) in a concentration-dependent manner. Depletion of NETs using the NE inhibitor Alvelestat significantly alleviated ferroptosis in VTE mice. Similarly, NETs depletion markedly attenuated thrombus formation and vein wall thickness in VTE mice. Notably, NETs treatment induced a significant elevation in total N6-Methyladenosine (m6A) RNA methylation level in HUVECs, with the most significant increase observed in methyltransferase-like 3 (METTL3). Mechanistically, the TLR4/NF-κB pathway was activated, and silencing METTL3 reversed the NETs-induced activation of this pathway in HUVECs. Rescue assays illustrated that METTL3 regulated the viability and ferroptosis of NETs-stimulated HUVECs by mediating TLR4 mRNA stability. Additionally, we found that HSYA exerted protective effects against ferroptosis in NETs-induced HUVECs and VTE mice. In summary, HSYA ameliorates VTE by depleting neutrophil extracellular traps through the inhibition of the TLR4/NF-κB pathway, thus providing a novel therapeutic strategy for treating VTE.

Nasal mRNA Nanovaccine with Key Activators of Dendritic and MAIT Cells for Effective Against Lung Tumor Metastasis in Mice Model

Background

Lung metastasis is a leading cause of cancer-related death. mRNA-based cancer vaccines have been demonstrated to be effective at inhibiting tumor growth. Intranasal immunization has emerged as a more effective method of inducing local immune responses against cancer cells in the lungs.

Methods

An innovative layered double hydroxide- and 5-OP-RU-based mRNA nanovaccine (Mg/Al LDH-5-OP-RU/mRNA) was synthesized via coprecipitation. The particle size distribution and zeta potential were measured, and the nanovaccine was observed by transmission electron microscopy. The functions and properties of the nanovaccine were evaluated via an mRNA-targeted delivery assay and measurement of dendritic cell (DC) and mucosa-associated invariant T (MAIT) cell maturation and activation. In addition, the cytotoxicity, antigen-specific T cell activation, cytokines, protective ability, and therapeutic ability of the nanovaccine were assessed in a mouse tumor model. Further, the immune cell composition was evaluated in tumors.

Results

The Mg/Al LDH-5-OP-RU/mRNA nanovaccine was efficiently delivered into lung-draining mediastinal lymph nodes (MLNs), and it activated dendritic cells (DCs) and mucosa-associated invariant T (MAIT) cells after intranasal administration. Moreover, the optimized dual-activating mRNA nanovaccine efficiently transfected DC cells and expressed antigen proteins in DC cells. An HPV-associated tumor model revealed that the intranasal delivery of the Mg/Al LDH-5-OP-RU/E7 mRNA nanovaccine significantly prevented the lung metastasis of tumors and had a therapeutic effect on established metastatic tumor nodules in the lungs. Mechanistically, the enhanced activation of DC and MAIT cells induced by the Mg/Al LDH-5-OP-RU/E7 mRNA nanovaccine increased the production of immune-stimulating cytokines and decreased the secretion of immunosuppressive cytokines, which led to the expansion and activation of memory T cells targeting the E7 antigen, a reduction in the population of neutrophils, and differentiation of tumor -associated macrophages to the M1 phenotype in the lungs.

Conclusion

These results highlight the potential of the innovative nasal mRNA nanovaccine for both preventing and treating tumor metastasis in the lungs.

Identification of a biomarker to predict doxorubicin/cisplatin chemotherapy efficacy in osteosarcoma patients using primary, recurrent and metastatic specimens

BACKGROUND

Doxorubicin and cisplatin are both first-line chemotherapeutics for osteosarcoma (OS) treatment. However, the efficacy of doxorubicin/cisplatin chemotherapy varies considerably. Thus, identifying an efficient diagnostic biomarker to distinguish patients with good and poor responses to doxorubicin/cisplatin chemotherapy is of paramount importance.

METHODS

To predict the efficacy of doxorubicin/cisplatin chemotherapy, we analyzed the differentially expressed proteins in 37 resected OS samples, which were categorized into the primary group (PG), the recurrent group (RG) and the metastatic group (MG). The characteristics of the enriched differentially expressed proteins were assessed via GO and KEGG analyses. Protein‒protein interactions were identified to determine the relationships among the differentially expressed proteins. Receiver operating characteristic (ROC) curve analyses were performed to explore the clinical significance of the differentially expressed proteins. Parallel reaction monitoring (PRM) was used to validate the candidate proteins. Immunohistochemical (IHC) staining was performed to confirm the expression of cathepsin (CTSG) in patients with good and poor response to doxorubicin/cisplatin.

RESULTS

A total of 9458 proteins were identified and quantified, among which 143 and 208 exhibited significant changes (|log2FC|>1, p < 0.05) in the RG and MG compared with the PG, respectively. GO and KEGG enrichment led to the identification of neutrophil extracellular traps (NETs). ROC curve analyses revealed 74 and 86 proteins with areas under the curve greater than 0.7 in the RG and MG, respectively. PRM validation revealed the statistical significance of CTSG, which is involved in NET formation, at the protein level in both the RG and MG. IHC staining of another cohort revealed that CTSG was prominently upregulated in the poor response group after treatment with doxorubicin/cisplatin.

CONCLUSION

CTSG and its associated NETs are potential biomarkers with which the efficacy of doxorubicin/cisplatin chemotherapy could be predicted in OS patients.

Global research trends and focus on the link between neutrophil extracellular traps and tumor: a bibliometric and visualization analysis from 2006 to 2024

Background

Neutrophil extracellular traps (NETs) have long been consistently considered an innate immune defense against foreign pathogens, but this oversimplified view has decelerated the progression of perceiving NET biology in chronic diseases. It is now increasingly accepted that NETs are not exclusive to anti-infection responses, but are also central players with a double-edged sword role in cancer progression. NETs have gradually emerged as tumor diagnostic, predictive, and prognostic biomarkers, and strenuous endeavors have been devoted to tapping their potential as new therapeutic targets. Correspondingly, the boom in studies on NETs and tumors in recent years has achieved a series of scientific outputs, which opens up a new perspective for perceiving the sophisticated landscapes of the tumor immune microenvironment. However, there is still much room to translate NET-targeted immunotherapies into clinical practice. Therefore, it is necessary to explore the knowledge structure and latent hotspots of the links between NETs and tumors using bibliometric analysis.

Methods

NETs and tumor publications from 2006 to 2024 were extracted from the Web of Science Core Collection. Bibliometric analysis and visualization were conducted using Microsoft Excel, VOSviewer, CiteSpace, and R-bibliometrix.

Results

The analysis included 1,339 publications authored by 7,747 scholars affiliated with 1,926 institutions across 70 countries/regions with relevant articles published in 538 journals. Despite China's maximum number of publications, the United States has continued to dominate the field as a global cooperation center with overwhelming citation counts. Frontiers in Immunology published the most number of publications, whereas Blood was the most cited journal. Wagner, Denisa D. and Kaplan, Mariana J. are concurrently in both the top 10 most prolific authors and cited author lists. Tumor microenvironment and immunotherapy will likely be the focus of future research.

Conclusions

A comprehensive bibliometric analysis was first conducted to map the current landscape and knowledge structure of the link between NETs and tumors in the hope of providing guidance and fresh perspectives for further research in this field. NETs are promising antitumor targets, and perhaps the eventual destination in the realm is to translate NET-targeted immunotherapies into clinical practice.

NETs: Important players in cancer progression and therapeutic resistance

Neutrophil extracellular traps (NETs) are web-like structures composed of cytoplasmic contents, DNA chromatin and various granular proteins released by neutrophils in response to viruses, bacteria, immune complexes and cytokines. Studies have shown that NETs can promote the occurrence, development and metastasis of tumors. In this paper, the mechanism underlying the formation and degradation of NETs and the malignant biological behaviors of NETs, such as the promotion of tumor cell proliferation, epithelial mesenchymal transition, extracellular matrix remodeling, angiogenesis, immune evasion and tumor-related thrombosis, are described in detail. NETs are being increasingly studied as therapeutic targets for tumors. We have summarized strategies for targeting NETs or interfering with NET-cancer cell interactions and explored the potential application value of NETs as biomarkers in cancer diagnosis and treatment, as well as the relationship between NETs and therapeutic resistance.

Prognostic impact and immunotherapeutic implications of NETosis-related gene signature in gastric cancer patients

The role of NETosis and its related molecules remains unclear in gastric cancer. The data used in this study was directly downloaded from the Cancer Genome Atlas (TCGA) database. All analysis and plots are completed in R software using diverse R packages. In our study, we collected the list of NETosis-related genes from previous publications. Based on the list and expression profile of gastric cancer patients from the TCGA database, we identified the NETosis-related genes significantly correlated with patients survival. Then, CLEC6A, BST1 and TLR7 were identified through LASSO regression and multivariate Cox regression analysis for prognosis model construction. This prognosis model showed great predictive efficiency in both training and validation cohorts. We noticed that the high-risk patients might have a worse survival performance. Next, we explored the biological enrichment difference between high- and low-risk patients and found that many carcinogenic pathways were upregulated in the high-risk patients. Meanwhile, we investigated the genomic instability, mutation burden and immune microenvironment difference between high- and low-risk patients. Moreover, we noticed that low-risk patients were more sensitive to immunotherapy (85.95% vs. 56.22%). High-risk patients were more sensitive to some small molecules compounds like camptothecin_1003, cisplatin_1005, cytarabine_1006, nutlin-3a (-)_1047, gemcitabine_1190, WZ4003_1614, selumetinib_1736 and mitoxantrone_1810. In summary, our study comprehensively explored the role of NETosis-related genes in gastric cancer, which can provide direction for relevant studies.