Neutrophil extracellular traps produced during inflammation awaken dormant cancer cells in mice

Not just sugar: metabolic control of neutrophil development and effector functions

The mammalian immune system is constantly surveying our tissues to clear pathogens and maintain tissue homeostasis. In order to fulfill these tasks, immune cells take up nutrients to supply energy for survival and for directly regulating effector functions via their cellular metabolism, a process now known as immunometabolism. Neutrophilic granulocytes, the most abundant leukocytes in the human body, have a short half-life and are permanently needed in the defense against pathogens. According to a long-standing view, neutrophils were thought to primarily fuel their metabolic demands via glycolysis. Yet, this view has been challenged, as other metabolic pathways recently emerged to contribute to neutrophil homeostasis and effector functions. In particular during neutrophilic development, the pentose phosphate pathway, glycogen synthesis, oxidative phosphorylation, and fatty acid oxidation crucially promote neutrophil maturation. At steady state, both glucose and lipid metabolism sustain neutrophil survival and maintain the intracellular redox balance. This review aims to comprehensively discuss how neutrophilic metabolism adapts during development, which metabolic pathways fuel their functionality, and how these processes are reconfigured in case of various diseases. We provide several examples of hereditary diseases, in which mutations in metabolic enzymes validate their critical role for neutrophil function.

Wrecking neutrophil extracellular traps and antagonizing cancer-associated neurotransmitters by interpenetrating network hydrogels prevent postsurgical cancer relapse and metastases

Tumor-promoting niche after incomplete surgery resection (SR) can lead to more aggressive local progression and distant metastasis with augmented angiogenesis-immunosuppressive tumor microenvironment (TME). Herein, elevated neutrophil extracellular traps (NETs) and cancer-associated neurotransmitters (CANTs, e.g., catecholamines) are firstly identified as two of the dominant inducements. Further, an injectable fibrin-alginate hydrogel with high tissue adhesion has been constructed to specifically co-deliver NETs inhibitor (DNase I)-encapsulated PLGA nanoparticles and an unselective β-adrenergic receptor blocker (propranolol). The two components (i.e., fibrin and alginate) can respond to two triggers (thrombin and Ca2+, respectively) in postoperative bleeding to gelate, shaping into an interpenetrating network (IPN) featuring high strength. The continuous release of DNase I and PR can wreck NETs and antagonize catecholamines to decrease microvessel density, blockade myeloid-derived suppressor cells, secrete various proinflammatory cytokines, potentiate natural killer cell function and hamper cytotoxic T cell exhaustion. The reprogrammed TME significantly suppress locally residual and distant tumors, induce strong immune memory effects and thus inhibit lung metastasis. Thus, targetedly degrading NETs and blocking CANTs enabled by this in-situ IPN-based hydrogel drug depot provides a simple and efficient approach against SR-induced cancer recurrence and metastasis.

ZBTB46 coordinates angiogenesis and immunity to control tumor outcome

Tumor angiogenesis and immunity show an inverse correlation in cancer progression and outcome1. Here, we report that ZBTB46, a repressive transcription factor and a widely accepted marker for classical dendritic cells (DCs)2,3, controls both tumor angiogenesis and immunity. Zbtb46 was downregulated in both DCs and endothelial cells by tumor-derived factors to facilitate robust tumor growth. Zbtb46 downregulation led to a hallmark pro-tumor microenvironment (TME), including dysfunctional vasculature and immunosuppressive conditions. Analysis of human cancer data revealed a similar association of low ZBTB46 expression with an immunosuppressive TME and a worse prognosis. In contrast, enforced Zbtb46 expression led to TME changes to restrict tumor growth. Mechanistically, Zbtb46-deficient endothelial cells were highly angiogenic, and Zbtb46-deficient bone marrow progenitors upregulated Cebpb and diverted the DC program to immunosuppressive myeloid lineage output, potentially explaining the myeloid lineage skewing phenomenon in cancer4. Conversely, enforced Zbtb46 expression normalized tumor vessels and, by suppressing Cebpb, skewed bone marrow precursors toward immunostimulatory myeloid lineage output, leading to an immune-hot TME. Remarkably, Zbtb46 mRNA treatment synergized with anti-PD1 immunotherapy to improve tumor management in preclinical models. These findings identify ZBTB46 as a critical factor for angiogenesis and for myeloid lineage skewing in cancer and suggest that maintaining its expression could have therapeutic benefits.

Navigating the biophysical landscape: how physical cues steer the journey of bone metastatic tumor cells

Many tumors prefer to metastasize to bone, but the underlying mechanisms remain elusive. The human skeletal system has unique physical properties, that are distinct from other organs, which play a key role in directing the behavior of tumor cells within bone. Understanding the physical journey of tumor cells within bone is crucial. In this review we discuss bone metastasis in the context of how physical cues in the bone vasculature and bone marrow niche regulate the fate of tumor cells. Our objective is to inspire innovative diagnostic and therapeutic approaches for bone metastasis from a mechanobiological perspective.

Immune mediated support of metastasis: Implication for bone invasion

Bone is a common organ affected by metastasis in various advanced cancers, including lung, breast, prostate, colorectal, and melanoma. Once a patient is diagnosed with bone metastasis, the patient's quality of life and overall survival are significantly reduced owing to a wide range of morbidities and the increasing difficulty of treatment. Many studies have shown that bone metastasis is closely related to bone microenvironment, especially bone immune microenvironment. However, the effects of various immune cells in the bone microenvironment on bone metastasis remain unclear. Here, we described the changes in various immune cells during bone metastasis and discussed their related mechanisms. Osteoblasts, adipocytes, and other non-immune cells closely related to bone metastasis were also included. This review also summarized the existing treatment methods and potential therapeutic targets, and provided insights for future studies of cancer bone metastasis.

Mechanisms of metastatic colorectal cancer

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

Intraoperative Cavity Local Delivery System with NETs-Specific Drug Release for Post-Breast Cancer Surgery Recurrence Correction

Postoperative breast cancer recurrence is tricky due to the limited therapeutic options. Transforming growth factors-β (TGF-β) is vital in promoting postoperative tumor recurrence. However, conventional blocking strategies fail to satisfy both bio-safety and sufficient relapse correction. Neutrophil extracellular traps (NETs) are essential for the spatiotemporal dynamics of TGF-β at tumor-resection sites, whose unique mechanism for local TGF-β amplification could remarkably increase the risk of relapse after surgery. Herein, the principle of NETs formation is ingeniously utilized to construct a surgical residual cavity hydrogel that mimics NETs formation. The hydrogel is prepared based on the electrostatic interaction between histidine (His) and sodium alginate (Alg). Then, arginine deiminase 4 (PAD4) protein is released during NETs formation. Simultaneously, the electrical property of His in hydrogel changes automatically, which further lead to promising localized release of anti-TGF-β. The hydrogel system can realize specific and selective drug release at targeted NETs site over a prolonged period while exhibiting excellent biocompatibility. Superior breast cancer recurrence inhibition is achieved by suppressing TGF-β and related indicators, impeding epithelial-mesenchymal transition (EMT) progression, and rectifying the locally exacerbated immunosuppressive environment within NETs. The novel NETs local microenvironment drug release functional hydrogel will provide inspiration for postoperative recurrence correction strategies.

Paraneoplastic leukocytosis induces NETosis and thrombosis in bladder cancer PDX model

Paraneoplastic leukocytosis (PNL) in genitourinary cancer, though rare, can indicate aggressive behavior and poor outcomes. It has been potentially linked to cancer expressing G-CSF and GM-CSF, along with their respective receptors, exerting an autocrine/paracrine effect. In our study, we successfully established four patient-derived xenograft (PDX) lines and related cell lines from urothelial cancer (UC), conducting next-generation sequencing (NGS) for genetic studies. UC-PDX-LN1, originating from bladder cancer, exhibited two druggable targets - HRAS and ERCC2 - responding well to chemotherapy and targeted therapy, though not to tipifarnib, an HRAS inhibitor. Transcriptome analysis post-treatment illuminated potential mechanisms, with index protein analysis confirming their anticancer pathways. Mice implanted with UC-PDX-LN1 mirrored PNL observed in the patient's original tumor. Cytokine array and RT-PCR analyses revealed high levels of G-CSF and GM-CSF in our PDX and cell lines, along with their presence in culture media and tumor cysts.Leukocytosis within small vessels in and around the tumor, associated with NETosis and thrombus formation, suggested a mechanism wherein secreted growth factors were retained, further fueling tumor growth via autocrine/paracrine signaling. Disrupting this cancer cell-NETosis-thrombosis cycle, we demonstrated that anti-neutrophil or anticoagulant interventions enhanced chemotherapy's antitumor effects or prolonged survival in mice, even though these drugs lacked direct antitumor efficacy when used independently. Clinical observations in bladder cancer patients revealed PNL in 1.61% of cases (35/2162) with associated poor prognosis. These findings propose a novel approach, advocating for the combination of anticancer/NETosis/thrombosis strategies for managing UC patients presenting with PNL in clinical settings.

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.

Radiotherapy-Driven Nanoprobes Targeting for Visualizing Tumor Infiltration Dynamics and Inducing Ferroptosis in Myeloid-Derived Suppressor Cells

Myeloid-derived suppressor cells (MDSCs) significantly hinder the immune response to tumor radiotherapy (RT) because of their massive accumulation in tumors after RT, resulting in immunosuppression and poor clinical prognosis. Herein, we developed an anti-PD-L1 antibody-conjugated iron oxide nanoprobe (Fe3O4-αPD-L1) to target and induce ferroptosis in MDSCs, thereby alleviating RT resistance. Overexpression of PD-L1 in MDSCs following RT enables noninvasive in vivo magnetic resonance and positron emission tomography imaging using 89Zr-labeled nanoprobes to track the movement of MDSCs and their infiltration into the tumor. After uptake by MDSCs that infiltrated the tumor, Fe3O4-αPD-L1 nanoprobes were mainly found within the lysosome and triggered the Fenton reaction, resulting in the generation of abundant reactive oxygen species. This process leads to ferroptosis of MDSCs, characterized by lipid peroxidation and mitochondrial dysfunction, and effectively reprograms the immunosuppressive environment within the tumor following RT. This study highlights a strategy for monitoring and regulating the fate of MDSCs to alleviate RT resistance and ultimately achieve improved treatment outcomes.

Recent advances in sialic acid-based active targeting chemoimmunotherapy promoting tumor shedding: a systematic review

Tumors have always been a major public health concern worldwide, and attempts to look for effective treatments have never ceased. Sialic acid is known to be a crucial element for tumor development and its receptors are highly expressed on tumor-associated immune cells, which perform significant roles in establishing the immunosuppressive tumor microenvironment and further boosting tumorigenesis, progression, and metastasis. Obviously, it is essential to consider sophisticated crosstalk between tumors, the immune system, and preparations, and understand the links between pharmaceutics and immunology. Sialic acid-based chemoimmunotherapy enables active targeting drug delivery via mediating the recognition between the sialic acid-modified nano-drug delivery system represented by liposomes and sialic acid-binding receptors on tumor-associated immune cells, which inhibit their activity and utilize their homing ability to deliver drugs. Such a "Trojan horse" strategy has remarkably improved the shortcomings of traditional passive targeting treatments, unexpectedly promoted tumor shedding, and persistently induced robust immunological memory, thus highlighting its prospective application potential for targeting various tumors. Herein, we review recent advances in sialic acid-based active targeting chemoimmunotherapy to promote tumor shedding, summarize the current viewpoints on the tumor shedding mechanism, especially the formation of durable immunological memory, and analyze the challenges and opportunities of this attractive approach.

Prognostic Significance of Plasma Neutrophil Extracellular Trap Levels in Patients with Non-Small Cell Lung Cancer Treated with Immune Checkpoint Inhibitors

Neutrophil extracellular traps (NETs) released from neutrophils are related to cancer progression. However, the relationship between the therapeutic effects of immune checkpoint inhibitors (ICIs) such as anti-PD-1 and anti-PD-L1 antibodies and plasma NET concentration in patients with non-small cell lung cancer (NSCLC) is poorly understood. In this study, concentrations of citrullinated histone H3 (CitH3), a surrogate marker of NETs, in plasma before/after treatment were examined in patients with advanced or recurrent NSCLC undergoing ICI treatment (n = 185). The clinical significances of NET levels before/after treatment and posttreatment changes were statistically evaluated. As a result, multivariate Cox analysis showed that high NET levels before treatment were statistically significant predictors of unfavorable overall survival (OS; p < 0.001, HR 1.702, 95% CI 1.356-2.137) and progression-free survival (PFS; p < 0.001, HR 1.566, 95% CI 1.323-1.855). The Kaplan-Meier curves showed significant separation between the high- and low-NET groups in OS (p = 0.002) and PFS (p < 0.001). Additionally, high NET levels after treatment were also significantly associated with worse OS (p < 0.001) and PFS (p < 0.001) by multivariate Cox analysis. Notably, the pretreatment NET levels were significantly correlated with the plasma levels of NET-related inflammatory cytokines, such as IL-6 and IL-8, and with NET-related gene expression and immune-suppressive profile in peripheral blood mononuclear cells. Our findings suggest that NETs released from activated neutrophils might reduce the clinical efficacy of ICIs in patients with NSCLC.

Differential Regulation of Wingless-Wnt/c-Jun N-Terminal Kinase Crosstalk via Oxidative Eustress in Primary and Metastatic Colorectal Cancer Cells

In the tumor microenvironment (TME), ROS production affects survival, progression, and therapy resistance in colorectal cancer (CRC). H2O2-mediated oxidative stress can modulate Wnt/β-catenin signaling and metabolic reprogramming of the TME. Currently, it is unclear how mild/moderate oxidative stress (eustress) modulates Wnt/β-catenin/APC and JNK signaling relationships in primary and metastatic CRC cells. In this study, we determined the effects of the H2O2 concentration inducing eustress on isogenic SW480 and SW620 cells, also in combination with JNK inhibition. We assessed cell viability, mitochondrial respiration, glycolysis, and Wnt/β-catenin/APC/JNK gene and protein expression. Primary CRC cells were more sensitive to H2O2 eustress combined with JNK inhibition, showing a reduction in viability compared to metastatic cells. JNK inhibition under eustress reduced both glycolytic and respiratory capacity in SW620 cells, indicating a greater capacity to adapt to TME. In primary CRC cells, H2O2 alone significantly increased APC, LEF1, LRP6, cMYC and IL8 gene expression, whereas in metastatic CRC cells, this effect occurred after JNK inhibition. In metastatic but not in primary tumor cells, eustress and inhibition of JNK reduced APC, β-catenin, and pJNK protein. The results showed differential cross-regulation of Wnt/JNK in primary and metastatic tumor cells under environmental eustress conditions. Further studies would be useful to validate these findings and explore their therapeutic potential.

Neutrophils exposed to a cholesterol metabolite secrete extracellular vesicles that promote epithelial-mesenchymal transition and stemness in breast cancer cells

Small extracellular vesicles (sEVs) are emerging as critical mediators of intercellular communication in the tumor microenvironment (TME). Here, we investigate the mechanisms by which sEVs derived from neutrophils treated with the cholesterol metabolite, 27-hydroxycholesterol (27HC), influence breast cancer progression. sEVs released from 27HC treated neutrophils enhance epithelial-mesenchymal transition (EMT) and stem-like properties in breast cancer cells, resulting in loss of adherence, increased migratory capacity and resistance to cytotoxic chemotherapy. Decreased microRNAs (miRs) within the sEVs resulted in activation of the WNT/β-catenin signaling pathway in recipient cells and suggest that this may be a predominant pathway for stem-like phenotype and EMT. Our findings underscore a novel mechanism by which 27HC-modulated neutrophils contribute to breast cancer pathophysiology through EV-mediated intercellular communication, suggesting potential therapeutic targets in cancer treatment.

The Interplay between Extracellular Matrix Remodeling and Cancer Therapeutics

The extracellular matrix (ECM) is an abundant noncellular component of most solid tumors known to support tumor progression and metastasis. The interplay between the ECM and cancer therapeutics opens up new avenues in understanding cancer biology. While the ECM is known to protect the tumor from anticancer agents by serving as a biomechanical barrier, emerging studies show that various cancer therapies induce ECM remodeling, resulting in therapy resistance and tumor progression. This review discusses critical issues in this field including how the ECM influences treatment outcome, how cancer therapies affect ECM remodeling, and the challenges associated with targeting the ECM. Significance: The intricate relationship between the extracellular matrix (ECM) and cancer therapeutics reveals novel insights into tumor biology and its effective treatment. While the ECM may protect tumors from anti-cancer agents, recent research highlights the paradoxical role of therapy-induced ECM remodeling in promoting treatment resistance and tumor progression. This review explores the key aspects of the interplay between ECM and cancer therapeutics.

Mouse Models of Metastasis and Dormancy

Metastasis is the ultimate and often lethal stage of cancer. Metastasis occurs in three phases that may vary across individuals: First, dissemination from the primary tumor. Second, tumor dormancy at the metastatic site where micrometastatic cancer cells remain quiescent or, in dynamic cycles of proliferation and elimination, remaining clinically undetectable. Finally, cancer cells are able to overcome microenvironmental constraints for outgrowth, or the formation of clinically detectable macrometastases that colonize distant organs and are largely incurable. A variety of approaches have been used to model metastasis to elucidate molecular mechanisms and identify putative therapeutic targets. In particular, metastatic dormancy has been challenging to model in vivo due to the sparse numbers of cancer cells in micrometastasis nodules and the long latency times required for tumor outgrowth. Here, we review state-of-the art genetically engineered mouse, syngeneic, and patient-derived xenograft approaches for modeling metastasis and dormancy. We describe the advantages and limitations of various metastasis models, novel findings enabled by such approaches, and highlight opportunities for future improvement.

Neutrophil extracellular traps in cancer

Neutrophil extracellular traps (NETs), which consist of chromatin DNA studded with granule proteins, are released by neutrophils in response to both infectious and sterile inflammation. Beyond the canonical role in defense against pathogens, the extrusion of NETs also contributes to the initiation, metastasis, and therapeutic response of malignant diseases. Recently, NETs have been implicated in the development and therapeutic responses of various types of tumors. Although extensive work regarding inflammation in tumors has been reported, a comprehensive summary of how these web-like extracellular structures initiate and propagate tumor progression under the specific microenvironment is lacking. In this review, we demonstrate the initiators and related signaling pathways that trigger NETs formation in cancers. Additionally, this review will outline the current molecular mechanisms and regulatory networks of NETs during dormant cancer cells awakening, circulating tumor cells (CTCs) extravasation, and metastatic recurrence of cancer. This is followed by a perspective on the current and potential clinical potential of NETs as therapeutic targets in the treatment of both local and metastatic disease, including the improvement of the efficacy of existing therapies.

CD177 on neutrophils engages stress-related behavioral changes in male mice

Persistent psychological stress can affect immune homeostasis and is a key factor in the development of depression. Many efforts are focused on the identifcation of pathways that link the immune system and mood disorders. Here, we found that psychological stress caused an increase in the frequency of brain-associated neutrophils and the level of neutrophil-specific antigen CD177 on peripheral neutrophils in male mice. Upregulated levels of blood CD177 are associated with depression in humans. Neutrophil depletion or Cd177 deficiency protected mice from stress-induced behavioral deficits. Importantly, adoptive transfer of CD177+ neutrophils from stressed mice increased the frequency of brain-associated leukocytes, including neutrophils, and caused behavioral defects in naive mice. These effects may be related to the endothelial adhesion advantage of CD177+ neutrophils and the interference of serine protease on endothelial junction. Our findings suggest a critical link between circulating CD177+ neutrophils and psychological stress-driven behavioral disorder.

Neutrophils in pancreatic ductal adenocarcinoma: bridging preclinical insights to clinical prospects for improved therapeutic strategies

INTRODUCTION

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive malignancy characterized by a dismal five-year survival rate of less than 10%. Neutrophils are key components of the innate immune system, playing a pivotal role in the PDAC immune microenvironment.

AREAS COVERED

This review provides a comprehensive survey of the pivotal involvement of neutrophils in the tumorigenesis and progression of PDAC. Furthermore, it synthesizes preclinical and clinical explorations aimed at targeting neutrophils within the milieu of PDAC, subsequently proposing a conceptual framework to propel further inquiry focused on enhancing the therapeutic efficacy of PDAC through neutrophil-targeted strategies. PubMed and Web of Science databases were utilized for researching neutrophils in pancreatic cancer publications prior to 2024.

EXPERT OPINION

Neutrophils play roles in promoting tumor growth and metastasis in PDAC and are associated with poor prognosis. However, the heterogeneity and plasticity of neutrophils and their complex relationships with other immune cells and extracellular matrix also provide new insights for immunotherapy targeting neutrophils to achieve a better prognosis for PDAC.

In vivo interaction screening reveals liver-derived constraints to metastasis

It is estimated that only 0.02% of disseminated tumour cells are able to seed overt metastases1. While this suggests the presence of environmental constraints to metastatic seeding, the landscape of host factors controlling this process remains largely unclear. Here, combining transposon technology2 and fluorescence niche labelling3, we developed an in vivo CRISPR activation screen to systematically investigate the interactions between hepatocytes and metastatic cells. We identify plexin B2 as a critical host-derived regulator of liver colonization in colorectal and pancreatic cancer and melanoma syngeneic mouse models. We dissect a mechanism through which plexin B2 interacts with class IV semaphorins on tumour cells, leading to KLF4 upregulation and thereby promoting the acquisition of epithelial traits. Our results highlight the essential role of signals from the liver parenchyma for the seeding of disseminated tumour cells before the establishment of a growth-promoting niche. Our findings further suggest that epithelialization is required for the adaptation of CRC metastases to their new tissue environment. Blocking the plexin-B2-semaphorin axis abolishes metastatic colonization of the liver and therefore represents a therapeutic strategy for the prevention of hepatic metastases. Finally, our screening approach, which evaluates host-derived extrinsic signals rather than tumour-intrinsic factors for their ability to promote metastatic seeding, is broadly applicable and lays a framework for the screening of environmental constraints to metastasis in other organs and cancer types.

Collagen XVII promotes dormancy of colorectal cancer cells by activating mTORC2 signaling

Tumor dormancy is the underpinning for cancer relapse and chemoresistance, leading to massive cancer-related death in colorectal cancer (CRC). However, our comprehension of the mechanisms dictating tumor dormancy and strategies for eliminating dormant tumor cells remains restricted. In this study, we identified that collagen XVII (COL17A1), a hemidesmosomal transmembrane protein, can promote the dormancy of CRC cells. The upregulation of COL17A1 was observed to prolong quiescence periods and diminish drug susceptibility of CRC cells. Mechanistically, COL17A1 acts as a scaffold, enhancing the crosstalk between mTORC2 and Akt, thereby instigating the mTORC2-mediated dormant signaling. Notably, the activation of mTORC2 is contingent upon the intracellular domain of COL17A1, regardless of its ectodomain shedding. Our findings underscore a pivotal role of the COL17A1-mTORC2 axis in CRC dormancy, suggesting that mTORC2-specific inhibitors may hold therapeutic prospects for the eradication of dormant tumor cells.

Cancer stem cell mimicry for immune evasion and therapeutic resistance

Cancer stem cells (CSCs) are heterogeneous, possess self-renewal attributes, and orchestrate important crosstalk in tumors. We propose that the CSC state represents "mimicry" by cancer cells that leads to phenotypic plasticity. CSC mimicry is suggested as CSCs can impersonate immune cells, vasculo-endothelia, or lymphangiogenic cells to support cancer growth. CSCs facilitate both paracrine and juxtracrine signaling to prime tumor-associated immune and stromal cells to adopt pro-tumoral phenotypes, driving therapeutic resistance. Here, we outline the ingenuity of CSCs' mimicry in their quest to evade immune detection, which leads to immunotherapeutic resistance, and highlight CSC-mimicry-targeted therapeutic strategies for robust immunotherapy.

Machine learning framework develops neutrophil extracellular traps model for clinical outcome and immunotherapy response in lung adenocarcinoma

Neutrophil extracellular traps (NETs) are novel inflammatory cell death in neutrophils. Emerging studies demonstrated NETs contributed to cancer progression and metastases in multiple ways. This study intends to provide a prognostic NETs signature and therapeutic target for lung adenocarcinoma (LUAD) patients. Consensus cluster analysis performed by 38 reported NET-related genes in TCGA-LUAD cohorts. Then, WGCNA network was conducted to investigate characteristics genes in clusters. Seven machine learning algorithms were assessed for training of the model, the optimal model was picked by C-index and 1-, 3-, 5-year ROC value. Then, we constructed a NETs signature to predict the overall survival of LUAD patients. Moreover, multi-omics validation was performed based on NETs signature. Finally, we constructed stable knockdown critical gene LUAD cell lines to verify biological functions of Phospholipid Scramblase 1 (PLSCR1) in vitro and in vivo. Two NETs-related clusters were identified in LUAD patients. Among them, C2 cluster was provided as "hot" tumor phenotype and exhibited a better prognosis. Then, WGCNA network identified 643 characteristic genes in C2 cluster. Then, Coxboost algorithm proved its optimal performance and provided a prognostic NETs signature. Multi-omics revealed that NETs signature was involved in an immunosuppressive microenvironment and predicted immunotherapy efficacy. In vitro and in vivo experiments demonstrated that knockdown of PLSCR1 inhibited tumor growth and EMT ability. Besides, cocultural assay indicated that the knockdown of PLSCR1 impaired the ability of neutrophils to generate NETs. Finally, tissue microarray (TMA) for LUAD patients verified the prognostic value of PLSCR1 expression. In this study, we focus on emerging hot topic NETs in LUAD. We provide a prognostic NETs signature and identify PLSCR1 with multiple roles in LUAD. This work can contribute to risk stratification and screen novel therapeutic targets for LUAD patients.

The Multifaceted Role of Neutrophils in NSCLC in the Era of Immune Checkpoint Inhibitors

Lung cancer is the most common cause of cancer-related death in both males and females in the U.S. and non-small-cell lung cancer (NSCLC) accounts for 85%. Although the use of first- or second-line immune checkpoint inhibitors (ICIs) exhibits remarkable clinical benefits, resistance to ICIs develops over time and dampens the efficacy of ICIs in patients. Tumor-associated neutrophils (TANs) have an important role in modulating the tumor microenvironment (TME) and tumor immune response. The major challenge in the field is to characterize the TANs in NSCLC TME and understand the link between TAN-related immunosuppression with ICI treatment response. In this review, we summarize the current studies of neutrophil interaction with malignant cells, T-cells, and other components in the TME. Ongoing clinical trials are aimed at utilizing reagents that have putative effects on tumor-associated neutrophils, in combination with ICI. Elevated neutrophil populations and neutrophil-associated factors could be potential therapeutic targets to enhance anti-PD1 treatment in NSCLC.

Citrullinated Histone H3, a Marker for Neutrophil Extracellular Traps, Is Associated with Poor Prognosis in Cutaneous Squamous Cell Carcinoma Developing in Patients with Recessive Dystrophic Epidermolysis Bullosa

Recessive dystrophic epidermolysis bullosa (RDEB) is a rare severe hereditary skin disease characterized by skin and mucosa fragility, resulting in blister formation. The most severe complication in RDEB patients is the development of cutaneous squamous cell carcinoma (SCC), leading to premature death. There is a great deal of evidence suggesting a permissive tumor microenvironment (TME) as a driver of SCC development in RDEB patients. In a cohort of RDEB patients, we characterized the immune profiles of RDEB-SCCs and compared them with clinical, histopathological, and prognostic features. RDEB-SCCs were subdivided into four groups based on their occurrence (first onset or recurrences) and grading according to clinical, histopathological parameters of aggressiveness. Thirty-eight SCCs from 20 RDEB patients were analyzed. Five RDEB patients experienced an unfavorable course after the diagnosis of the first SCC, with early recurrence or metastasis, whereas 15 patients developed multiple SCCs without metastasis. High-risk primary RDEB-SCCs showed a higher neutrophil-to-lymphocyte ratio in the tumor microenvironment and an increased proportion of neutrophil extracellular traps (NETs). Additionally, citrullinated histone H3, a marker of NETs, was increased in the serum of RDEB patients with high-risk primary SCC, suggesting that this modified form of histone H3 may serve as a potential blood marker of unfavorable prognosis in RDEB-SCCs.

Picoliter Single-Cell Reactor for Proteome Profiling by In Situ Cell Lysis, Protein Immobilization, Digestion, and Droplet Transfer

Global profiling of single-cell proteomes can reveal cellular heterogeneity, thus benefiting precision medicine. However, current mass spectrometry (MS)-based single-cell proteomic sample processing still faces technical challenges associated with processing efficiency and protein recovery. Herein, we present an innovative sample processing platform based on a picoliter single-cell reactor (picoSCR) for single-cell proteome profiling, which involves in situ protein immobilization and sample transfer. PicoSCR helped minimize surface adsorptive losses by downscaling the processing volume to 400 pL with a contact area of less than 0.4 mm2. Besides, picoSCR reached highly efficient cell lysis and digestion within 30 min, benefiting from optimal reagent and high reactant concentrations. Using the picoSCR-nanoLC-MS system, over 1400 proteins were identified from an individual HeLa cell using data-dependent acquisition mode. Proteins with copy number below 1000 were identified, demonstrating this system with a detection limit of 1.7 zmol. Furthermore, we profiled the proteome of circulating tumor cells (CTCs). Data are available via ProteomeXchange with the identifier PXD051468. Proteins associated with epithelial-mesenchymal transition and neutrophil extracellular traps formation (which are both related to tumor metastasis) were observed in all CTCs. The cellular heterogeneity was revealed by differences in signaling pathways within individual cells. These results highlighted the potential of the picoSCR platform to help discover new biomarkers and explore differences in biological processes between cells.

Neutrophil-derived migrasomes are an essential part of the coagulation system

Migrasomes are organelles that are generated by migrating cells. Here we report the key role of neutrophil-derived migrasomes in haemostasis. We found that a large number of neutrophil-derived migrasomes exist in the blood of mice and humans. Compared with neutrophil cell bodies and platelets, these migrasomes adsorb and enrich coagulation factors on the surface. Moreover, they are highly enriched with adhesion molecules, which enable them to preferentially accumulate at sites of injury, where they trigger platelet activation and clot formation. Depletion of neutrophils, or genetic reduction of the number of these migrasomes, significantly decreases platelet plug formation and impairs coagulation. These defects can be rescued by intravenous injection of purified neutrophil-derived migrasomes. Our study reveals neutrophil-derived migrasomes as a previously unrecognized essential component of the haemostasis system, which may shed light on the cause of various coagulation disorders and open therapeutic possibilities.

Synergistic antitumor activity by dual blockade of CCR1 and CXCR2 expressed on myeloid cells within the tumor microenvironment

BACKGROUND

Chemokine signaling within the tumor microenvironment can promote tumor progression. Although CCR1 and CXCR2 on myeloid cells could be involved in tumor progression, it remains elusive what effect would be observed if both of those are blocked.

METHODS

We employed two syngeneic colorectal cancer mouse models: a transplanted tumor model and a liver metastasis model. We generated double-knockout mice for CCR1 and CXCR2, and performed bone marrow (BM) transfer experiments in which sub-lethally irradiated wild-type mice were reconstituted with BM from either wild-type, Ccr1-/-, Cxcr2-/- or Ccr1-/-Cxcr2-/- mice.

RESULTS

Myeloid cells that express MMP2, MMP9 and VEGF were accumulated around both types of tumors through CCR1- and CXCR2-mediated pathways. Mice reconstituted with Ccr1-/-Cxcr2-/- BM exhibited the strongest suppression of tumor growth and liver metastasis compared with other three groups. Depletion of CCR1+CXCR2+ myeloid cells led to a higher frequency of CD8+ T cells, whereas the numbers of Ly6G+ neutrophils, FOXP3+ Treg cells and CD31+ endothelial cells were significantly decreased. Furthermore, treatment with a neutralizing anti-CCR1 mAb to mice reconstituted with Cxcr2-/- BM significantly suppressed tumor growth and liver metastasis.

CONCLUSION

Dual blockade of CCR1 and CXCR2 pathways in myeloid cells could be an effective therapy against colorectal cancer.

NETscape or NEThance: tailoring anti-cancer therapy

Neutrophils, major regulators of innate immunity, have recently emerged as key components of the tumor microenvironment. The role of neutrophils in cancer has been linked to their ability to form neutrophil extracellular traps (NETs), structures composed of decondensed DNA decorated with enzymes that are released into the extracellular space. Here, we discuss the pivotal roles of NETs in influencing responses to anticancer therapies such as chemotherapy, radiotherapy, immunotherapy, and targeted therapy. Highlighting recent insights, we delve into the dual nature of NETs in the context of anticancer treatments, examining their potential to either counteract or enhance treatment outcomes. Strategic targeting of NETs may be a promising avenue for crafting combination therapies to counteract resistance or enhance anticancer treatments' efficacy.

Neutrophil extracellular traps modulate chemotherapy efficacy and its adverse side effects

Neutrophils, major regulator of innate immunity have recently emerged as key components of the tumor microenvironment. The role of neutrophils in cancer has been linked to their ability to form neutrophil extracellular traps (NETs), structures composed of decondensed DNA decorated with enzymes that are released into the extracellular space. Here, we discuss the pivotal roles of NETs, in influencing responses to chemotherapy and its severe adverse effect. Highlighting recent insights, we discuss the dual nature of NETs in the context of chemotherapy treatment, examining their potential to either counteract or enhance treatment outcomes. Strategic targeting of NETs emerges as a promising avenue for determining combination therapies that could help counteracting resistance or enhancing chemotherapy efficacy as well as limiting complications due to this type of treatment.

Tumor Dormancy and Reactivation: The Role of Heat Shock Proteins

Tumors are a heterogeneous group of cell masses originating in various organs or tissues. The cellular composition of the tumor cell mass interacts in an intricate manner, influenced by humoral, genetic, molecular, and tumor microenvironment cues that dictate tumor growth or suppression. As a result, tumors undergo a period of a dormant state before their clinically discernible stage, which surpasses the clinical dormancy threshold. Moreover, as a genetically imprinted strategy, early-seeder cells, a distinct population of tumor cells, break off to dock nearby or extravasate into blood vessels to secondary tissues, where they form disseminated solitary dormant tumor cells with reversible capacity. Among the various mechanisms underlying the dormant tumor mass and dormant tumor cell formation, heat shock proteins (HSPs) might play one of the most important roles in how the dormancy program plays out. It is known that numerous aberrant cellular processes, such as malignant transformation, cancer cell stemness, tumor invasion, metastasis, angiogenesis, and signaling pathway maintenance, are influenced by the HSPs. An accumulating body of knowledge suggests that HSPs may be involved in the angiogenic switch, immune editing, and extracellular matrix (ECM) remodeling cascades, crucial genetically imprinted strategies important to the tumor dormancy initiation and dormancy maintenance program. In this review, we highlight the biological events that orchestrate the dormancy state and the body of work that has been conducted on the dynamics of HSPs in a tumor mass, as well as tumor cell dormancy and reactivation. Additionally, we propose a conceptual framework that could possibly underlie dormant tumor reactivation in metastatic relapse.

A Two-Pronged Delivery Strategy Disrupting Positive Feedback Loop of Neutrophil Extracellular Traps for Metastasis Suppression

Neutrophil extracellular traps (NETs) severely affect tumor metastasis through a self-perpetuating feedback loop involving two key steps: (1) mitochondrial aerobic respiration-induced hypoxia promotes NET formation and (2) NETs enhance mitochondrial metabolism to exacerbate hypoxia. Herein, we propose a two-pronged approach with the activity of NET-degrading and mitochondrion-damaging by simultaneously targeting drugs to NETs and tumor mitochondria of this loop. In addition to specifically recognizing and eliminating extant NETs, the NET-targeting nanoparticle also reduces NET-induced mitochondrial biogenesis, thus inhibiting the initial step of the feedback loop and mitigating extant NETs' impact on tumor metastasis. Simultaneously, the mitochondrion-targeting system intercepts mitochondrial metabolism and alleviates tumor hypoxia, inhibiting neutrophil infiltration and subsequent NET formation, which reduces the source of NETs and disrupts another step of the self-amplifying feedback loop. Together, the combination significantly reduces the formation of NET-tumor cell clusters by disrupting the interaction between NETs and tumor mitochondria, thereby impeding the metastatic cascade including tumor invasion, hematogenous spread, and distant colonization. This work represents an innovative attempt to disrupt the feedback loop in tumor metastasis, offering a promising therapeutic approach restraining NET-assisted metastasis.

Predictive value of dynamic changes in peripheral blood inflammation and blood lipid-related indices for the lung cancer treatment efficacy

To investigate the dynamics of inflammation and lipid-related indicators in lung cancer patients and their impact on treatment efficacy. A retrospective analysis was conducted on 133 lung cancer patients who seek for primary treatment at Wujin Hospital Affiliated to Jiangsu University from January 2019 to August 2022. The inflammation and blood lipid-related indicators were collected 1 week before treatment and after 2 cycles of treatment. We compared the changes in these indicators among patients with different treatment methods and outcomes. The diagnostic value of the dynamic changes in each index for disease progression was calculated using the ROC curve. The risk factors influencing disease development were identified using multifactorial logistic regression analysis. After 2 cycles of treatment, the white blood cell count (WBC, P<0.001), neutrophil count (NC, P<0.001), neutrophil-to-lymphocyte ratio (NLR, P<0.001) in the disease progression (PD) group were significantly increased, triglyceride (TG, P=0.023), apolipoprotein A1 (APO-A1, P=0.009) was significantly decreased. The results showed that ∆NC had the highest sensitivity (88.24%) in predicting disease progression, and ∆WBC had the best specificity (77.78%). Multivariate regression analysis showed that ΔWBC (P<0.001), ΔTG (P=0.041), and treatment method (P=0.010) were independent risk factors for disease progression (PD). The changes of WBC and TG before and after treatment are promising indicators for predicting the progression of lung cancer and may offer a new direction for lung cancer treatment.

Shaping the immune-suppressive microenvironment on tumor-associated myeloid cells through tumor-derived exosomes

Tumor-associated myeloid cells (TAMCs) play a crucial role in orchestrating the dynamics of the tumor immune microenvironment. This heterogeneous population encompasses myeloid-derived suppressor cells, tumor-associated macrophages and dendritic cells, all of which contribute to the establishment of an immunosuppressive milieu that fosters tumor progression. Tumor-derived exosomes (TEXs), small extracellular vesicles secreted by tumor cells, have emerged as central mediators in intercellular communication within the tumor microenvironment. In this comprehensive review, we explore the intricate mechanisms through which TEXs modulate immune-suppressive effects on TAMCs and their profound implications in cancer progression. We delve into the multifaceted ways in which TEXs influence TAMC functions, subsequently affecting tumor immune evasion. Furthermore, we elucidate various therapeutic strategies aimed at targeting TEX-mediated immune suppression, with the ultimate goal of bolstering antitumor immunity.

Colorectal cancer and dormant metastases: Put to sleep or destroy?

After reading the review by An et al "Biological factors driving colorectal cancer metastasis", which covers the problem of the metastasis of colorectal cancer (CRC), I had a desire to discuss with readers one of the exciting problems associated with dormant metastases. Most deaths from CRCs are caused by metastases, which can be detected both at diagnosis of the primary tumor and several years or even decades after treatment. This is because tumor cells that enter the bloodstream can be destroyed by the immune system, cause metastatic growth, or remain dormant for a long time. Dormant tumor cells may not manifest themselves throughout a person's life or, after some time and under appropriate conditions, may give rise to the growth of metastases. In this editorial, we will discuss the most important features of dormant metastases and the mechanisms of premetastatic niche formation, as well as factors that contribute to the activation of dormant metastases in CRCs. We will pay special attention to the possible mechanisms involved in the formation of circulating tumor cell complexes and the choice of therapeutic strategies that promote the dormancy or destruction of tumor cells in CRCs.

Biology and Total Synthesis of n-3 Docosapentaenoic Acid-Derived Specialized Pro-Resolving Mediators

Research over the last 25 years related to structural elucidations and biological investigations of the specialized pro-resolving mediators has spurred great interest in targeting these endogenous products in total synthesis. These lipid mediators govern the resolution of inflammation as potent and stereoselective agonists toward individual G-protein-coupled receptors, resulting in potent anti-inflammatory activities demonstrated in many human disease models. Specialized pro-resolving mediators are oxygenated polyunsaturated products formed in stereoselective and distinct biosynthetic pathways initiated by various lipoxygenase and cyclooxygenase enzymes. In this review, the reported stereoselective total synthesis and biological activities of the specialized pro-resolving mediators biosynthesized from the polyunsaturated fatty acid n-3 docosapentaenoic acid are presented.

Effects of surgical trauma and intraoperative blood loss on tumour progression

Surgery is the primary treatment of choice for tumours, and improves prognosis, prolongs survival and is potentially curative. Previous studies have described the effects of anaesthesia and changes in the neuroendocrine, circulatory and sympathetic nervous systems on postoperative cancer progression. There is growing evidence that intraoperative blood loss is an independent prognostic factor for tumour recurrence, postoperative inflammation is a predictor of cancer prognosis, and immunosuppressive status correlates with the degree of surgical damage. This paper outlines the potential mechanisms by which blood loss, surgical trauma and postoperative immunosuppressive status contribute to tumour growth and recurrence by reducing intraoperative haemorrhage and perioperative immunotherapy, thereby reducing tumour growth and recurrence, and improving long-term prognosis.

A New Approach for Assessment of Neutrophil Extracellular Traps Through Immunofluorescence Staining in Whole Blood Smears

Neutrophils, constituting 50%-70% of circulating leukocytes, play crucial roles in host defense and exhibit anti-tumorigenic properties. An elevated peripheral blood neutrophil-to-lymphocyte ratio is associated with decreased survival rates in cancer patients. In response to exposure to various antigens, neutrophils release neutrophil granular proteins, which combine to form web-like structures known as neutrophil extracellular traps (NETs). Previously, the relative percentage of NETs was found to be increased in resected tumor tissue samples from patients with gastrointestinal malignancies. The presence of NETs in peripheral blood is indicative of underlying pathological conditions. Hence, employing a non-invasive method to detect NETs in peripheral blood, along with other diagnostic tests, shows potential as a valuable tool not just for identifying different inflammatory disorders but also for assessing disease severity and determining patient suitability for surgical resection. While reliable methods exist for identifying NETs in tissue, accurately quantifying them in whole blood remains challenging. Many previous methods are time-consuming and rely on a limited set of markers that are inadequate for fully characterizing NETs. Therefore, we established a unique sensitive smear immunofluorescence assay based on blood smears to identify NETs in only as little as 2 μL of whole blood. To identify the NET complexes that have enhanced specificities, this combines the use of various antibodies against neutrophil-specific CD15, NET-specific myeloperoxidase (MPO), citrullinated histone H3 (Cit H3), and nuclear DNA. This protocol offers an easy, affordable, rapid, and non-invasive method for identifying NETs; thus, it can be utilized as a diagnostic marker and targeted through various therapeutic approaches for treating human malignancies. Key features • Characterization of neutrophil extracellular traps in whole blood smears through immunofluorescence staining. • Affordable and quantitative approach to neutrophil extracellular trap detection.

Neutrophil Targeting Platform Reduces Neutrophil Extracellular Traps for Improved Traumatic Brain Injury and Stroke Theranostics

Traumatic brain injuries (TBI) and stroke are major causes of morbidity and mortality in both developing and developed countries. The complex and heterogeneous pathophysiology of TBI and cerebral ischemia-reperfusion injury (CIRI), in addition to the blood-brain barrier (BBB) resistance, is a major barrier to the advancement of diagnostics and therapeutics. Clinical data showed that the severity of TBI and stroke is positively correlated with the number of neutrophils in peripheral blood and brain injury sites. Furthermore, neutrophil extracellular traps (NETs) released by neutrophils correlate with worse TBI and stroke outcomes by impairing revascularization and vascular remodeling. Therefore, targeting neutrophils to deliver NETs inhibitors to brain injury sites and reduce the formation of NETs can be an optimal strategy for TBI and stroke therapy. Herein, the study designs and synthesizes a reactive oxygen species (ROS)-responsive neutrophil-targeting delivery system loaded with peptidyl arginine deiminase 4 (PAD4) inhibitor, GSK484, to prevent the formation of NETs in brain injury sites, which significantly inhibited neuroinflammation and improved neurological deficits, and improved the survival rate of TBI and CIRI. This strategy may provide a groundwork for the development of targeted theranostics of TBI and stroke.

Neutrophil-derived PAD4 induces citrullination of CKMT1 exacerbates mucosal inflammation in inflammatory bowel disease

Peptidyl arginine deiminase 4 (PAD4) plays a pivotal role in infection and inflammatory diseases by facilitating the formation of neutrophil extracellular traps (NETs). However, the substrates of PAD4 and its exact role in inflammatory bowel disease (IBD) remain unclear. In this study, we employed single-cell RNA sequencing (scRNA-seq) and substrate citrullination mapping to decipher the role of PAD4 in intestinal inflammation associated with IBD. Our results demonstrated that PAD4 deficiency alleviated colonic inflammation and restored intestinal barrier function in a dextran sulfate sodium (DSS)-induced colitis mouse model. scRNA-seq analysis revealed significant alterations in intestinal cell populations, with reduced neutrophil numbers and changes in epithelial subsets upon PAD4 deletion. Gene expression analysis highlighted pathways related to inflammation and epithelial cell function. Furthermore, we found that neutrophil-derived extracellular vesicles (EVs) carrying PAD4 were secreted into intestinal epithelial cells (IECs). Within IECs, PAD4 citrullinates mitochondrial creatine kinase 1 (CKMT1) at the R242 site, leading to reduced CKMT1 protein stability via the autophagy pathway. This action compromises mitochondrial homeostasis, impairs intestinal barrier integrity, and induces IECs apoptosis. IEC-specific depletion of CKMT1 exacerbated intestinal inflammation and apoptosis in mice with colitis. Clinical analysis of IBD patients revealed elevated levels of PAD4, increased CKMT1 citrullination, and decreased CKMT1 expression. In summary, our findings highlight the crucial role of PAD4 in IBD, where it modulates IECs plasticity via CKMT1 citrullination, suggesting that PAD4 may be a potential therapeutic target for IBD.

Extracellular proteolysis in cancer: Proteases, substrates, and mechanisms in tumor progression and metastasis

A vast ensemble of extracellular proteins influences the development and progression of cancer, shaped and reshaped by a complex network of extracellular proteases. These proteases, belonging to the distinct classes of metalloproteases, serine proteases, cysteine proteases, and aspartic proteases, play a critical role in cancer. They often become dysregulated in cancer, with increases in pathological protease activity frequently driven by the loss of normal latency controls, diminished regulation by endogenous protease inhibitors, and changes in localization. Dysregulated proteases accelerate tumor progression and metastasis by degrading protein barriers within the extracellular matrix (ECM), stimulating tumor growth, reactivating dormant tumor cells, facilitating tumor cell escape from immune surveillance, and shifting stromal cells toward cancer-promoting behaviors through the precise proteolysis of specific substrates to alter their functions. These crucial substrates include ECM proteins and proteoglycans, soluble proteins secreted by tumor and stromal cells, and extracellular domains of cell surface proteins, including membrane receptors and adhesion proteins. The complexity of the extracellular protease web presents a significant challenge to untangle. Nevertheless, technological strides in proteomics, chemical biology, and the development of new probes and reagents are enabling progress and advancing our understanding of the pivotal importance of extracellular proteolysis in cancer.

Integrating integrins with the hallmarks of cancer

Epithelial cells adhere to a specialized extracellular matrix called the basement membrane which allows them to polarize and form epithelial tissues. The extracellular matrix provides essential physical scaffolding and biochemical and biophysical cues required for tissue morphogenesis, differentiation, function, and homeostasis. Epithelial cell adhesion to the extracellular matrix (i.e., basement membrane) plays a critical role in organizing epithelial tissues, separating the epithelial cells from the stroma. Epithelial cell detachment from the basement membrane classically results in death, though detachment or invasion through the basement membrane represents a critical step in carcinogenesis. Epithelial cells bind to the extracellular matrix via specialized matrix receptors, including integrins. Integrins are transmembrane receptors that form a mechanical linkage between the extracellular matrix and the intracellular cytoskeleton and are required for anchorage-dependent cellular functions such as proliferation, migration, and invasion. The role of integrins in the development, growth, and dissemination of multiple types of carcinomas has been investigated by numerous methodologies, which has led to great complexity. To organize this vast array of information, we have utilized the "Hallmarks of Cancer" from Hanahan and Weinberg as a convenient framework to discuss the role of integrins in the pathogenesis of cancers. This review explores this biology and how its complexity has impacted the development of integrin-targeted anti-cancer therapeutics.

Pancreatectomy Induces Cancer-Promoting Neutrophil Extracellular Traps

BACKGROUND

Neutrophil extracellular traps (NETs) occur when neutrophil chromatin is decondensed and extruded into the extracellular space in a web-like structure. Originally described as an anti-microbial function, this process has been implicated in the pathogenesis of pancreatic disease. In addition, NETs are upregulated during physiologic wound-healing and coagulation. This study evaluated how the inflammatory response to pancreatic surgery influences NET formation.

METHODS

For this study, 126 patients undergoing pancreatectomy gave consent before participation. Plasma was collected at several time points (preoperatively and through the postoperative outpatient visit). Plasma levels of NET markers, including cell-free DNA (cfDNA), citrullinated histone H3 (CitH3), interleukin (IL)-8, IL-6, and granulocyte colony-stimulating factor (G-CSF) were measured using enzyme-linked immunosorbent assay (ELISA). Patient clinical data were retrospectively collected from a prospectively maintained database.

RESULTS

After pancreatic resection, NET markers (cfDNA and CitH3) were elevated, peaking on postoperative days 3 and 4. This increase in NETs was due to an inherent change in neutrophil biology. Postoperatively, NET-inducing cytokines (IL-8, IL-6, and G-CSF) were increased, peaking early in the postoperative course. The patients undergoing the robotic approach had a reduction in NETs during the postoperative period compared with those who underwent the open approach. The patients who experienced a pancreatic leak had an increase in NET markers during the postoperative period.

CONCLUSIONS

Pancreatectomy induces cancer-promoting NET formation. The minimally invasive robotic approach may induce fewer NETs, although the current analysis was limited by selection bias. Pancreatic leak resulted in increased NETs. Further study into the potential for NET inhibition during the perioperative period is warranted.

Advances in the molecular regulation mechanism of tumor dormancy and its therapeutic strategy

Tumor dormancy is a stage in the growth and development of malignant cells and is one of the biological characteristics of malignant cells. Complex transitions involving dormant tumor cells between quiescent and proliferative states pose challenges for tumor eradication. This paper explores the biological features and molecular mechanisms of tumor dormancy and highlights emerging therapies. The strategies discussed promise innovative clinical potential against malignant tumors. Understanding the mechanisms of dormancy can help provide valuable insights into the diagnosis and treatment of malignant tumors to advance the fight against this world problem.

A β-Carboline Derivate PAD4 Inhibitor Reshapes Neutrophil Phenotype and Improves the Tumor Immune Microenvironment against Triple-Negative Breast Cancer

Triple-negative breast cancer is a highly aggressive and heterogeneous breast cancer subtype characterized by early metastasis, poor prognosis, and high recurrence. Targeting histone citrullination-mediated chromatin dysregulation to induce epigenetic alterations shows great promise in TNBC therapy. We report the synthesis, optimization, and evaluation of a novel series of β-carboline-derived peptidyl arginine deiminase 4 inhibitors that exhibited potent inhibition of TNBC cell proliferation. The most outstanding PAD4 inhibitor, compound 28, hindered the PAD4-H3cit-NET signaling pathway and inhibited the growth of solid tumors and pulmonary metastatic nodules in the 4T1 in situ mouse model. Furthermore, 28 improved the tumor immune microenvironment by reshaping neutrophil phenotype, upregulating the proportions of dendritic cells and M1 macrophages, and reducing the amount of myeloid-derived suppressor cells. In conclusion, our work offered 28 as an efficacious PAD4 inhibitor that exerts a combination of conventional chemotherapy and immune-boosting effects, which represents a potential therapy strategy for TNBC.

Neutrophils in Cancer immunotherapy: friends or foes?

Neutrophils play a Janus-faced role in the complex landscape of cancer pathogenesis and immunotherapy. As immune defense cells, neutrophils release toxic substances, including reactive oxygen species and matrix metalloproteinase 9, within the tumor microenvironment. They also modulate the expression of tumor necrosis factor-related apoptosis-inducing ligand and Fas ligand, augmenting their capacity to induce tumor cell apoptosis. Their involvement in antitumor immune regulation synergistically activates a network of immune cells, bolstering anticancer effects. Paradoxically, neutrophils can succumb to the influence of tumors, triggering signaling cascades such as JAK/STAT, which deactivate the immune system network, thereby promoting immune evasion by malignant cells. Additionally, neutrophil granular constituents, such as neutrophil elastase and vascular endothelial growth factor, intricately fuel tumor cell proliferation, metastasis, and angiogenesis. Understanding the mechanisms that guide neutrophils to collaborate with other immune cells for comprehensive tumor eradication is crucial to enhancing the efficacy of cancer therapeutics. In this review, we illuminate the underlying mechanisms governing neutrophil-mediated support or inhibition of tumor progression, with a particular focus on elucidating the internal and external factors that influence neutrophil polarization. We provide an overview of recent advances in clinical research regarding the involvement of neutrophils in cancer therapy. Moreover, the future prospects and limitations of neutrophil research are discussed, aiming to provide fresh insights for the development of innovative cancer treatment strategies targeting neutrophils.

Tumor-neutrophil cross talk orchestrates the tumor microenvironment to determine the bladder cancer progression

The immune landscape of bladder cancer progression is not fully understood, and effective therapies are lacking in advanced bladder cancer. Here, we visualized that bladder cancer cells recruited neutrophils by secreting interleukin-8 (IL-8); in turn, neutrophils played dual functions in bladder cancer, including hepatocyte growth factor (HGF) release and CCL3highPD-L1high super-immunosuppressive subset formation. Mechanistically, c-Fos was identified as the mediator of HGF up-regulating IL-8 transcription in bladder cancer cells, which was central to the positive feedback of neutrophil recruitment. Clinically, compared with serum IL-8, urine IL-8 was a better biomarker for bladder cancer prognosis and clinical benefit of immune checkpoint blockade (ICB). Additionally, targeting neutrophils or hepatocyte growth factor receptor (MET) signaling combined with ICB inhibited bladder cancer progression and boosted the antitumor effect of CD8+ T cells in mice. These findings reveal the mechanism by which tumor-neutrophil cross talk orchestrates the bladder cancer microenvironment and provide combination strategies, which may have broad impacts on patients suffering from malignancies enriched with neutrophils.

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.

Neutrophil extracellular traps promote invasion and metastasis via NLRP3-mediated oral squamous cell carcinoma pyroptosis inhibition

Neutrophil extracellular traps (NETs) are reticular structures composed of neutrophil elastase (NE), cathepsin G (CG) and DNA-histone enzyme complexes. Accumulating evidence has revealed that NETs play important roles in tumor progression, metastasis, and thrombosis. However, our understanding of its clinical value and mechanism of action in oral squamous cell carcinoma (OSCC) is limited and has not yet been systematically described. Here, we aimed to investigate the clinical significance of NETs in OSCC and the mechanisms by which they affect its invasive and metastatic capacity. Our results demonstrated that high enrichment of NETs is associated with poor prognosis in OSCC, and mechanistic studies have shown that NE in NETs promotes invasion and metastasis via NLRP3-mediated inhibition of pyroptosis in OSCC. These findings may provide a new therapeutic approach for OSCC.

Susceptibility of Melanoma Cells to Targeted Therapy Correlates with Protection by Blood Neutrophils

Elevated levels of peripheral blood and tumor tissue neutrophils are associated with poorer clinical response and therapy resistance in melanoma. The underlying mechanism and the role of neutrophils in targeted therapy is still not fully understood. Serum samples of patients with advanced melanoma were collected and neutrophil-associated serum markers were measured and correlated with response to targeted therapy. Blood neutrophils from healthy donors and patients with advanced melanoma were isolated, and their phenotypes, as well as their in vitro functions, were compared. In vitro functional tests were conducted through nonadherent cocultures with melanoma cells. Protection of melanoma cell lines by neutrophils was assessed under MAPK inhibition. Blood neutrophils from advanced melanoma patients exhibited lower CD16 expression compared to healthy donors. In vitro, both healthy-donor- and patient-derived neutrophils prevented melanoma cell apoptosis upon dual MAPK inhibition. The effect depended on cell-cell contact and melanoma cell susceptibility to treatment. Interference with protease activity of neutrophils prevented melanoma cell protection during treatment in cocultures. The negative correlation between neutrophils and melanoma outcomes seems to be linked to a protumoral function of neutrophils. In vitro, neutrophils exert a direct protective effect on melanoma cells during dual MAPK inhibition. This study further hints at a crucial role of neutrophil-related protease activity in protection.