The complexity of neutrophils in health and disease: Focus on cancer

Bioinformatics Analysis and Experimental Verification Define Different Angiogenesis Subtypes in Endometrial Carcinoma and Identify a Prognostic Signature

Increasing evidence indicates that peripheral blood vessels play a pivotal role in regulating tumor growth with the presence of new blood vessels facilitating tumor growth and metastasis. Nevertheless, the impact of specific molecule-mediated angiogenesis on the tumor immune microenvironment (TIME) and individual prognosis of uterine corpus endometrial carcinoma (UCEC) remains uncertain. The transcriptome information on 217 prognostic angiogenesis-related genes was integrated, and the angiogenesis patterns of 506 UCEC patients in The Cancer Genome Atlas (TCGA) cohort were comprehensively evaluated. We identified five angiogenic subtypes, namely, EC1, EC2, EC3, EC4, and EC5, which differed significantly in terms of prognosis, clinicopathological features, cancer hallmarks, genomic mutations, TIME patterns, and immunotherapy responses. Additionally, an angiogenesis-related prognostic risk score (APRS) was constructed to enable an individualized comprehensive evaluation. In multiple cohorts, APRS demonstrated a powerful predictive ability for the prognosis of UCEC patients. Likewise, APRS was confirmed to be associated with clinicopathological features, genomic mutations, cancer hallmarks, and TIME patterns in UCEC patients. The predictability of APRS for immune checkpoint inhibitor (ICI) therapy was also salient. Subsequently, the expression levels of four angiogenesis-related hub genes were verified by qRT-PCR, immunohistochemistry, and single-cell sequencing data analysis. The effects of four representative genes on angiogenesis were validated by Wound-Healing and Transwell assays, tube formation assay in vitro, and tumor xenograft model in vivo. This study proffered a new classification of UCEC patients based on angiogenesis. The established APRS may contribute to individualized prognosis prediction and immunotherapy selections that are better suited for UCEC patients.

Neutrophil Elastase Remodels Mammary Tumors to Facilitate Lung Metastasis

Metastatic disease remains the leading cause of death due to cancer, yet the mechanism(s) of metastasis and its timely detection remain to be elucidated. Neutrophil elastase (NE), a serine protease secreted by neutrophils, is a crucial mediator of chronic inflammation and tumor progression. In this study, we used the PyMT model (NE+/+ and NE-/-) of breast cancer to interrogate the tumor-intrinsic and -extrinsic mechanisms by which NE can promote metastasis. Our results showed that genetic ablation of NE significantly reduced lung metastasis and improved metastasis-free survival. RNA-sequencing analysis of primary tumors indicated differential regulation of tumor-intrinsic actin cytoskeleton signaling pathways by NE. These NE-regulated pathways are critical for cell-to-cell contact and motility and consistent with the delay in metastasis in NE-/- mice. To evaluate whether pharmacologic inhibition of NE inhibited pulmonary metastasis and phenotypically mimicked PyMT NE-/- mice, we utilized AZD9668, a clinically available and specific NE inhibitor. We found AZD9668 treated PyMT-NE+/+ mice showed significantly reduced lung metastases, improved recurrence-free, metastasis-free and overall survival, and their tumors showed similar molecular alterations as those observed in PyMT-NE-/- tumors. Finally, we identified a NE-specific signature that predicts recurrence and metastasis in patients with breast cancer. Collectively, our studies suggest that genetic ablation and pharmacologic inhibition of NE reduces metastasis and extends survival of mouse models of breast cancer, providing rationale to examine NE inhibitors as a treatment strategy for the clinical management of patients with metastatic breast cancer.

CD14-CD10-CD45+HLA-DR-SSC+ neutrophils may be granulocytic myeloid-derived suppressor cell-like cells and relate to disease progression in non-Hodgkin's lymphoma patients

We explored the frequency of CD14-CD10-CD45+HLA-DR-SSC++ neutrophils (CD10- neutrophils) in patients with non-Hodgkin's lymphoma (NHL), and their immunologic characteristics and clinical significance. Patients with NHL who were newly diagnosed (NDP; n = 33), in remission (RMP; n = 28) and relapsed (RLP; n = 29) were included, and 47 volunteers were recruited as healthy controls (HCs). The frequency of CD10- neutrophils in the peripheral blood from HC and patients with NHL was detected. CD10- and CD10+ neutrophils were sorted, and their cytology was analyzed. CD3+ T cells were also isolated and cultured with the autologous CD10- or CD10+ neutrophils, after which the proliferation and death rates of T cells were determined. The levels of arginase-1 (Arg-1) and reactive oxygen species (ROS) in CD10+ or CD10- neutrophils were examined. Few CD10- neutrophils were detected in HCs but were significantly elevated in patients with NHL, especially in NDP and RLP. In addition, CD10- neutrophils in NDP with advanced stage and high risk were markedly higher than those in NDP with limited stage and low risk. In RMP and RLP, the relapse-free survival and overall survival in patients with high CD10- neutrophils were shorter than those with low CD10- neutrophils. CD10- neutrophils from patients with NHL, which mainly consist of immature neutrophils, inhibit T-cell proliferation and facilitate T-cell death. Furthermore, a significant increase was observed in Arg-1 expression, along with an increase to a certain extent in ROS. CD10- neutrophils in patients with NHL have characteristics of myeloid-derived suppressor cells and may be related to disease progression and poor prognosis.

The Role and Mechanism of Paeoniae Radix Alba in Tumor Therapy

Tumors have a huge impact on human life and are now the main cause of disease-related deaths. The main means of treatment are surgery and radiotherapy, but they are more damaging to the organism and have a poor postoperative prognosis. Therefore, we urgently need safe and effective drugs to treat tumors. In recent years, Chinese herbal medicines have been widely used in tumor therapy as complementary and alternative therapies. Medicinal and edible herbs are popular and have become a hot topic of research, which not only have excellent pharmacological effects and activities, but also have almost no side effects. Therefore, as a typical medicine and food homology, some components of Paeoniae Radix Alba (PRA, called Baishao in China) have been shown to have good efficacy and safety against cancer. Numerous studies have also shown that Paeoniae Radix Alba and its active ingredients treat cancer through various pathways and are also one of the important components of many antitumor herbal compound formulas. In this paper, we reviewed the literature on the intervention of Paeoniae Radix Alba in tumors and its mechanism of action in recent years and found that there is a large amount of literature on its effect on total glucosides of paeony (TGP) and paeoniflorin (PF), as well as an in-depth discussion of the mechanism of action of Paeoniae Radix Alba and its main constituents, with a view to promote the clinical development and application of Paeoniae Radix Alba in the field of antitumor management.

Immune cell networking in solid tumors: focus on macrophages and neutrophils

The tumor microenvironment is composed of tumor cells, stromal cells and leukocytes, including innate and adaptive immune cells, and represents an ecological niche that regulates tumor development and progression. In general, inflammatory cells are considered to contribute to tumor progression through various mechanisms, including the formation of an immunosuppressive microenvironment. Macrophages and neutrophils are important components of the tumor microenvironment and can act as a double-edged sword, promoting or inhibiting the development of the tumor. Targeting of the immune system is emerging as an important therapeutic strategy for cancer patients. However, the efficacy of the various immunotherapies available is still limited. Given the crucial importance of the crosstalk between macrophages and neutrophils and other immune cells in the formation of the anti-tumor immune response, targeting these interactions may represent a promising therapeutic approach against cancer. Here we will review the current knowledge of the role played by macrophages and neutrophils in cancer, focusing on their interaction with other immune cells.

Development of a nomogram for predicting survival of breast cancer patients with neoadjuvant chemotherapy: a dynamic analysis for systemic inflammation response index

Background

The systemic inflammation response index (SIRI) has been reported to associate with survival outcomes in breast cancer patients. However, the effects of baseline SIRI and SIRI change after neoadjuvant chemotherapy (NACT) have not been thoroughly investigated. This study aimed to evaluate the role of baseline SIRI and SIRI change after NACT in predicting survival outcomes, and establish a nomogram based on SIRI.

Methods

A total of 260 patients diagnosed with breast cancer who received NACT between January 2014 and December 2018 at our hospital were included. The clinical data were retrospectively collected from the medical records management system. The associations between clinicopathological factors and baseline SIRI, pathological complete response (pCR) were analyzed by Student's t-test, Chi-squared test, or Fisher's exact test. The association between clinicopathological factors and disease-free survival (DFS) was evaluated by univariate and multivariate Cox regression analyses.

Results

Patients with a tumor-node-metastasis (TNM) stage of I, II, and III were 1.9%, 20.0%, and 78.1% respectively. The median follow-up time was 40 months, and 74 (28.5%) patients had cancer recurrence during the follow-up. Both in the univariate and multivariate analysis, Ki-67, pCR, and baseline SIRI were independent factors associated with DFS. Patients with low baseline SIRI had prolonged DFS compared with those with high baseline SIRI [≤1.6×109 vs. >1.6×109, hazard ratio (HR) =0.545, P=0.028]. In addition, SIRI change after NACT was also an independent factor associated with DFS, and patients with minor SIRI change had longer DFS than patients with major SIRI change (>50% or <-30% vs. ≤50% and ≥-30%, HR =1.721, P=0.037). Nomograms were established based on Ki-67, pCR, and baseline SIRI or SIRI change after NACT with a concordance index of 0.665 and 0.663 respectively, and the nomogram provided a convenient tool for predicting the probability of DFS.

Conclusions

The baseline SIRI and SIRI change after NACT could act as potential biomarkers for predicting survival outcomes in breast cancer. Besides, the nomogram with SIRI is an economic and convenient tool for predicting DFS. Larger prospective studies are needed to verify the results.

TIME Is Ticking for Cervical Cancer

Cervical cancer (CC) is a major health problem among reproductive-age females and comprises a leading cause of cancer-related deaths. Human papillomavirus (HPV) is the major risk factor associated with CC incidence. However, lifestyle is also a critical factor in CC pathogenesis. Despite HPV vaccination introduction, the incidence of CC is increasing worldwide. Therefore, it becomes critical to understand the CC tumor immune microenvironment (TIME) to develop immune cell-based vaccination and immunotherapeutic approaches. The current article discusses the immune environment in the normal cervix of adult females and its role in HPV infection. The subsequent sections discuss the alteration of different immune cells comprising CC TIME and their targeting as future therapeutic approaches.

Autonomous IL-36R signaling in neutrophils activates potent antitumor effector functions

While the rapid advancement of immunotherapies has revolutionized cancer treatment, only a small fraction of patients derive clinical benefit. Eradication of large, established tumors appears to depend on engaging and activating both innate and adaptive immune system components to mount a rigorous and comprehensive immune response. Identifying such agents is a high unmet medical need, because they are sparse in the therapeutic landscape of cancer treatment. Here, we report that IL-36 cytokine can engage both innate and adaptive immunity to remodel an immune-suppressive tumor microenvironment (TME) and mediate potent antitumor immune responses via signaling in host hematopoietic cells. Mechanistically, IL-36 signaling modulates neutrophils in a cell-intrinsic manner to greatly enhance not only their ability to directly kill tumor cells but also promote T and NK cell responses. Thus, while poor prognostic outcomes are typically associated with neutrophil enrichment in the TME, our results highlight the pleiotropic effects of IL-36 and its therapeutic potential to modify tumor-infiltrating neutrophils into potent effector cells and engage both the innate and adaptive immune system to achieve durable antitumor responses in solid tumors.

Neutrophil diversity in inflammation and cancer

Neutrophils are the most abundant circulating leukocytes in humans and the first immune cells recruited at the site of inflammation. Classically perceived as short-lived effector cells with limited plasticity and diversity, neutrophils are now recognized as highly heterogenous immune cells, which can adapt to various environmental cues. In addition to playing a central role in the host defence, neutrophils are involved in pathological contexts such as inflammatory diseases and cancer. The prevalence of neutrophils in these conditions is usually associated with detrimental inflammatory responses and poor clinical outcomes. However, a beneficial role for neutrophils is emerging in several pathological contexts, including in cancer. Here we will review the current knowledge of neutrophil biology and heterogeneity in steady state and during inflammation, with a focus on the opposing roles of neutrophils in different pathological contexts.

NK cells are never alone: crosstalk and communication in tumour microenvironments

Immune escape is a hallmark of cancer. The dynamic and heterogeneous tumour microenvironment (TME) causes insufficient infiltration and poor efficacy of natural killer (NK) cell-based immunotherapy, which becomes a key factor triggering tumour progression. Understanding the crosstalk between NK cells and the TME provides new insights for optimising NK cell-based immunotherapy. Here, we present new advances in direct or indirect crosstalk between NK cells and 9 specialised TMEs, including immune, metabolic, innervated niche, mechanical, and microbial microenvironments, summarise TME-mediated mechanisms of NK cell function inhibition, and highlight potential targeted therapies for NK-TME crosstalk. Importantly, we discuss novel strategies to overcome the inhibitory TME and provide an attractive outlook for the future.

Monitoring Blood Immune Cells in Patients with Advanced Small Cell Lung Cancer Undergoing a Combined Immune Checkpoint Inhibitor/Chemotherapy

In this exploratory prospective observational study on 40 small cell lung cancer (SCLC) patients treated with a combination of chemotherapy and immune checkpoint inhibitors, blood immune cells were characterized by multi-color flow cytometry at the baseline and at the third therapy cycle. The numbers of neutrophils and of T-, B-, and NK cells, as well as the frequency of HLA-DR^low monocytes, 6-SulfoLacNAc (slan)+ non-classical monocytes and circulating dendritic cell (DC) subtypes were determined. The prognostic value of the parameters was evaluated by the patient's survival analysis with overall survival (OS) as the primary endpoint. In addition, blood cell parameters from SCLC patients were compared to those from non-SCLC (NSCLC). The global median OS of patients was 10.4 ± 1.1 months. Disease progression (15% of patients) correlated with a higher baseline neutrophil/lymphocyte ratio (NLR), more HLA-DR^low monocytes, and lower NK cell and DC numbers. The risk factors for poor OS were the presence of brain/liver metastases, a baseline NLR ≥ 6.1, HLA-DR^low monocytes ≥ 21% of monocytes, slan+ non-classical monocytes < 0.12%, and/or CD1c+ myeloid DC < 0.05% of leukocytes. Lymphocytic subpopulations did not correlate with OS. When comparing biomarkers in SCLC versus NSCLC, SCLC had a higher frequency of brain/liver metastases, a higher NLR, the lowest DC frequencies, and lower NK cell numbers. Brain/liver metastases had a substantial impact on the survival of SCLC patients. At the baseline, 45% of SCLC patients, but only 24% of NSCLC patients, had between three and five risk factors. A high basal NLR, a high frequency of HLA-DR^low monocytes, and low levels of slan+ non-classical monocytes were associated with poor survival in all lung cancer histotypes. Thus, the blood immune cell signature might contribute to a better prediction of SCLC patient outcomes and may uncover the pathophysiological peculiarities of this tumor entity.

Assessing Leukocyte Profiles of Salamanders and Other Amphibians: A Herpetologists' Guide

Assessing numbers of leukocytes in salamanders and other amphibians can be useful metrics for understanding health or stress levels of individuals in a population. In this chapter we describe the procedures for obtaining blood samples from amphibians, preparing blood films for microscopy, counting, and identifying cells. We also provide reference values for amphibian leukocytes for use in interpreting leukocyte data. From our assessment of the published and unpublished literature, "non-stressed" salamanders would have a leukocyte profile where 60-70% of cells are lymphocytes, 17-30% are neutrophils, 1-4% are eosinophils, 4-12% are basophils, and 2-6% are monocytes. In Ambystoma spp., the eosinophil abundance can be notably higher (30% of all white blood cells), for reasons unknown. Finally, the neutrophil-lymphocyte ratio of most non-stressed salamanders tends to be between 0.3 and 0.4 (sometimes less), while the ratios of stressed salamanders tend to be over 1.0.

Emerging Role of Neutrophil Extracellular Traps in Gastrointestinal Tumors: A Narrative Review

Neutrophil extracellular traps (NETs) are extracellular fibrous networks consisting of depolymerized chromatin DNA skeletons with a variety of antimicrobial proteins. They are secreted by activated neutrophils and play key roles in host defense and immune responses. Gastrointestinal (GI) malignancies are globally known for their high mortality and morbidity. Increasing research suggests that NETs contribute to the progression and metastasis of digestive tract tumors, among them gastric, colon, liver, and pancreatic cancers. This article explores the formation of NETs and reviews the role that NETs play in the gastrointestinal oncologic microenvironment, tumor proliferation and metastasis, tumor-related thrombosis, and surgical stress. At the same time, we analyze the qualitative and quantitative detection methods of NETs in recent years and found that NETs are specific markers of coronavirus disease 2019 (COVID-19). Then, we explore the possibility of NET inhibitors for the treatment of digestive tract tumor diseases to provide a new, efficient, and safe solution for the future therapy of gastrointestinal tumors.

Heterogeneity of neutrophils in cancer: one size does not fit all

Neutrophils play an essential role in the defense against bacterial infections and orchestrate both the innate and adaptive immune responses. With their abundant numbers, diverse function and short life span, these cells are at the forefront of immune responses, and have gained attention in recent years because of their presence in tumor sites. Neutrophil involvement pertains to tumor cells' ability to construct a suitable tumor microenvironment (TME) that accelerates their own growth and malignancy, by facilitating their interaction with surrounding cells through the circulatory and lymphatic systems, thereby influencing tumor development and progression. Studies have indicated both pro- and anti-tumor properties of infiltrating neutrophils. The TME can exploit neutrophil function, recruitment, and even production, thus resulting in pro-tumor properties of neutrophils, including promotion of genetic instability, tumor cell proliferation, angiogenesis and suppression of anti-tumor or inflammatory response. In contrast, neutrophils can mediate anti-tumor resistance by direct cytotoxicity to the tumor cells or by facilitating anti-tumor functions via crosstalk with T cells. Here, we summarize current knowledge regarding the effects of neutrophil heterogeneity under homeostatic and tumor conditions, including neutrophil phenotype and function, in cancer biology.

Current knowledge on the early stages of human neutropoiesis

Polymorphonuclear neutrophils are no longer considered as a homogeneous population of terminally differentiated and short-lived cells that belong to the innate immune system only. In fact, data from the past decades have uncovered that neutrophils exhibit large phenotypic heterogeneity and functional versatility that render them more plastic than previously thought. Hence, their precise role as effector cells in inflammation, in immune response and in other pathophysiological processes, including tumors, needs to be better evaluated. In such a complex scenario, common knowledge of the differentiation of neutrophils in bone marrow refers to lineage precursors, starting from the still poorly defined myeloblasts, and proceeding sequentially to promyelocytes, myelocytes, metamyelocytes, band cells, segmented neutrophils, and mature neutrophils, with each progenitor stage being more mature and better characterized. Thanks to the development and utilization of cutting-edge technologies, novel information about neutrophil precursors at stages earlier than the promyelocytes, hence closer to the hematopoietic stem cells, is emerging. Accordingly, this review discusses the main findings related to the very early precursors of human neutrophils and provides our perspectives on human neutropoiesis.

Dihydrotanshinone I Inhibits the Lung Metastasis of Breast Cancer by Suppressing Neutrophil Extracellular Traps Formation

Breast cancer (BC) is a common female malignancy, worldwide. BC death is predominantly caused by lung metastasis. According to previous studies, Dihydrotanshinone I (DHT), a bioactive compound in Salvia miltiorrhiza Bunge (S. miltiorrhiza), has inhibitory effects on numerous cancers. Here, we investigated the anti-metastatic effect of DHT on BC, where DHT more strongly inhibited the growth of BC cells (MDA-MB-231, 4T1, MCF-7, and SKBR-3) than breast epithelial cells (MCF-10a). Additionally, DHT repressed the wound healing, invasion, and migration activities of 4T1 cells. In the 4T1 spontaneous metastasis model, DHT (20 mg/kg) blocked metastasis progression and distribution in the lung tissue by 74.9%. DHT reversed the formation of neutrophil extracellular traps (NETs) induced by phorbol 12-myristate 13-acetate, as well as ameliorated NETs-induced metastasis. Furthermore, it inhibited Ly6G⁺Mpo⁺ neutrophils infiltration and H3Cit expression in the lung tissues. RNA sequencing, western blot, and bioinformatical analysis indicated that TIMP1 could modulate DHT acting on lung metastasis inhibition. The study demonstrated a novel suppression mechanism of DHT on NETs formation to inhibit BC metastasis.

The changing landscape of immune cells in the fetal mouse testis

Fetal testis growth involves cell influx and extensive remodeling. Immediately after sex determination in mouse, macrophages enable normal cord formation and removal of inappropriately positioned cells. This study provides new information about macrophages and other immune cells after cord formation in fetal testes, including their density, distribution, and close cellular contacts. C57BL6J mouse testes from embryonic day (E) 13.5 to birth (post-natal day 0; PND0), were examined using immunofluorescence, immunohistochemistry, and RT-qPCR to identify macrophages (F4/80, CD206, MHCII), T cells (CD3), granulocytes/neutrophils (Ly6G), and germ cells (DDX4). F4/80⁺ cells were the most abundant, comprising 90% of CD45⁺ cells at E13.5 and declining to 65% at PND0. Changes in size, shape, and markers (CD206 and MHCII) documented during this interval align with the understanding that F4/80⁺ cells have different origins during embryonic life. CD3⁺ cells and F4/80⁻/MHCII⁺ were absent to rare until PND0. Ly6G⁺ cells were scarce at E13.5 but increased robustly by PND0 to represent half of the CD45⁺ cells. These immunofluorescence data were in accord with transcript analysis, which showed that immune marker mRNAs increased with testis age. F4/80⁺ and Ly6G⁺ cells were frequently inside cords adjacent to germ cells at E13.5 and E15.5. F4/80⁺ cells were often in clusters next to other immune cells. Macrophages inside cords at E13.5 and E15.5 (F4/80^Hi/CD206⁺) were different from macrophages at PND0 (F4/80^Dim/CD206⁻), indicating that they have distinct origins. This histological quantification coupled with transcript information identifies new cellular interactions for immune cells in fetal testis morphogenesis, and highlights new avenues for studies of their functional significance.

Neutrophil Extracellular Traps, Angiogenesis and Cancer

Human neutrophils, the most abundant circulating leukocytes, are fundamental components of the host response against different pathogens. Until a few years ago, neutrophils received limited attention in cancer immunology. Recently, it was discovered that both circulating, and tumor-associated, neutrophils possess functional plasticity when exposed to various inflammatory stimuli and in the tumor microenvironment. Neutrophils and their mediators can exert several pro-tumor activities in cancer and promote metastasis through different mechanisms. Angiogenesis plays a pivotal role in inflammation and tumor growth. Activated human neutrophils release several angiogenic factors [vascular endothelial growth factor-A (VEGF-A), angiopoietin-1 (ANGPT1), CXCL8, hepatocyte growth factor (HGF), and metalloproteinase 9 (MMP-9)] and form neutrophil extracellular traps (NETs). NETs promote tumor growth and metastasis formation through several mechanisms: they can awake dormant cancer cells, capture circulating tumor cells, coat and shield cancer cells, thus preventing CD8⁺- and natural killer (NK) cell-mediated cytotoxicity. ANGPTs released by endothelial and periendothelial mural cells induce platelet-activating factor (PAF) synthesis and neutrophil adhesion to endothelial cells. NETs can directly exert several proangiogenic activities in human endothelial cells and NETs induced by ANGPTs and PAF increase several aspects of angiogenesis in vitro and in vivo. A better understanding of the pathophysiological functions of NETs in cancer and angiogenesis could be of importance in the early diagnosis, prevention and treatment of tumors.

Chemokines as Regulators of Neutrophils: Focus on Tumors, Therapeutic Targeting, and Immunotherapy

Simple Summary

Neutrophils are the main leukocyte subset present in human blood and play a fundamental role in the defense against infections. Neutrophils are also an important component of the tumor stroma because they are recruited by selected chemokines produced by both cancer cells and other cells of the stroma. Even if their presence has been mostly associated with a bad prognosis, tumor-associated neutrophils are present in different maturation and activation states and can exert both protumor and antitumor activities. In addition, it is now emerging that chemokines not only induce neutrophil directional migration but also have an important role in their activation and maturation. For these reasons, chemokines and chemokine receptors are now considered targets to improve the antitumoral function of neutrophils in cancer immunotherapy.

Abstract

Neutrophils are an important component of the tumor microenvironment, and their infiltration has been associated with a poor prognosis for most human tumors. However, neutrophils have been shown to be endowed with both protumor and antitumor activities, reflecting their heterogeneity and plasticity in cancer. A growing body of studies has demonstrated that chemokines and chemokine receptors, which are fundamental regulators of neutrophils trafficking, can affect neutrophil maturation and effector functions. Here, we review human and mouse data suggesting that targeting chemokines or chemokine receptors can modulate neutrophil activity and improve their antitumor properties and the efficiency of immunotherapy.

Polymorphonuclear Neutrophils and Tumors: Friend or Foe?

Tumor microenvironment (TME) is a dynamic network that apart from tumor cells includes also cells of the immune system, e.g., neutrophils, which are recruited from blood circulation. In TME, neutrophils are strongly implicated in the direct and indirect interactions with tumor cells or other immune cells, and they play roles in both preventing and/or facilitating tumor progression and metastasis. The dual role of neutrophils is determined by their high plasticity and heterogeneity. Analogous to the macrophages, neutrophils can express antitumoral (N1) and protumoral (N2) phenotypes which differ substantially in morphology and function. N1 phenotype characterizes with a high cytotoxic and proinflammatory activities, while N2 phenotype with immunosuppressive and prometastatic properties. The antitumoral effect of neutrophils includes for example the production of reactive oxygen species or proapoptotic molecules. The protumoral action of neutrophils relies on releasing of proangiogenic and prometastatic mediators, immunosuppressive factors, as well as on direct helping tumor cells in extravasation process. This chapter summarizes the heterogeneity of neutrophils in TME, as well as their dual role on tumor cells.

Are Circulating Immune Cells a Determinant of Pancreatic Cancer Risk? A Prospective Study Using Epigenetic Cell Count Measures

BACKGROUND

Evidence is accumulating that immune cells play a prominent role in pancreatic cancer etiology but prospective investigations are missing.

METHODS

We conducted a nested case-control study within the European Prospective Investigation into Cancer and Nutrition (EPIC) study with 502 pairs of incident pancreatic cancer cases and matched controls. Relative counts of circulating immune cells (neutrophils and lymphocyte sublineages: total CD3+, CD8+, CD4+, and FOXP3+ regulatory T cells (Tregs) relative to nucleated cells, (white blood cells) were measured by qRT-PCR. ORs with 95% confidence intervals were estimated using logistic regressions, modeling relative counts of immune cells on a continuous scale.

RESULTS

Neither relative counts of immune cell types taken individually, nor mutually adjusted for each other were associated with pancreatic cancer risks. However, in subgroup analyses by strata of lag-time, higher relative counts of Tregs and lower relative counts of CD8+ were significantly associated with an increased pancreatic cancer risks in participants diagnosed within the first 5 years of follow-up.

CONCLUSIONS

These results might reflect reverse causation, due to higher relative counts of Tregs and lower counts of CD8+ cells among individuals with more advanced stages of latent pancreatic cancer, who are closer to the point of developing clinical manifest disease.

IMPACT

We have shown, for the first time, that increased relative counts of regulatory T cells and lower relative counts of CD8+, cytotoxic T cells may be associated with pancreatic cancer risk or relatively late-stage tumor development.See related commentary by Michaud and Kelsey, p. 2176.

Neutrophil-to-lymphocyte and platelet-to-lymphocyte ratios as predictors of outcomes in inflammatory breast cancer

Background: Inflammatory breast cancer (IBC) is uncommon, aggressive and associated with poor survival outcomes. The lack of prognostic biomarkers and therapeutic targets specific to IBC is an added challenge for clinical practice and research. Inflammatory biomarkers such as neutrophil-to-lymphocyte and platelet-to-lymphocyte ratios (NLR and PLR) demonstrated independent prognostic impact for survival in breast cancer. In our study, these biomarkers were investigated in a cohort of patients with nonmetastatic IBC. Methods: A retrospective cohort of 102 IBC patients with nonmetastatic disease was conducted at the Mohammed VI University Hospital (Oujda, Morocco) between January 2010 and December 2014. NLR and PLR were obtained from blood cell count at baseline before neoadjuvant chemotherapy (NACT) from patients' medical records. The receiver operating characteristic was used to find the optimal cut-off. Correlation between these blood-based biomarkers and response to NACT was analyzed by Chi-squared and Fisher's exact test. Their prognostic value for predicting disease-free survival (DFS) and overall survival (OS) was performed based on Cox regression models. Results: Totally, 102 patients with IBC were included in the analysis. Pathologic complete response (pCR) after NACT, defined by the absence of an invasive tumor in the breast tissues and nodes after surgery (ypT0 ypN0), was observed in eight patients (7.8%). NACT response was found to be associated with menopausal status (p = 0.039) and nodal status (p < 0.001). Patients with a low NLR had a higher pCR rate as compared with the high-NLR group (p = 0.043). However, the pCR rate was not significantly associated with age (p = 0.122), tumor side (p = 0.403), BMI (p = 0.615), histological grade (p = 0.059), hormone receptors status (p = 0.206), HER2 (p = 0.491) and PLR (p = 0.096). Pre-treatment blood-based NLR of 2.28 was used as the cut-off value to discriminate between high and low NLR according to the receiver operating characteristic curves. Similarly, a value of 178 was used as the cut off for PLR. Patients with low-NLR had a significantly better 5-year DFS (p < 0.001) and OS (p < 0.001) than the high-NLR group. Moreover, low-PLR was significantly associated with higher DFS (p = 0.001) and OS (p = 0.003). The NLR showed a significant prognostic impact for DFS (HR: 2.57; 95% CI: 1.43-4.61; p = 0.01) and for OS (HR: 2.92; 95% CI: 1.70-5.02; p < 0.001). Similarly, a meaningful association between PLR and 5-year DFS (HR: 1.95; 95% CI: 1.10-3.46; p = 0.021) and OS (HR: 1.82; 95% CI: 1.06-3.14; p = 0.03) was noticed. Conclusions: High NLR and PLR were found associated with reduced DFS and OS in nonmetastatic IBC. Further studies are awaited to confirm these findings.

Role of neutrophil-to-lymphocyte ratio as a prognostic biomarker in patients with breast cancer receiving neoadjuvant chemotherapy: a meta-analysis

OBJECTIVE

The neutrophil-to-lymphocyte ratio (NLR) is recognised as a suitable prognostic biomarker in patients with breast cancer. Nevertheless, the efficacy of this biomarker in predicting the pathological complete response (pCR) and survival in patients with breast cancer receiving neoadjuvant chemotherapy (NACT) is still controversial. This meta-analysis aimed to identify the association between baseline NLR and the prognosis of patients with breast cancer treated with NACT.

DESIGN

Meta-analysis.

DATA SOURCES

Relevant literature published before 1 May 2021 was searched using the Cochrane Library, Embase, PubMed and the Web of Science databases.

ELIGIBILITY CRITERIA

All studies involving patients with breast cancer treated with NACT and peripheral blood pretreatment NLR recorded as a dichotomous variable were included.

DATA EXTRACTION AND SYNTHESIS

Two researchers independently extracted and evaluated OR/HR and its 95% CIs of survival outcomes and clinicopathological parameters.

RESULTS

A total of 19 studies were identified. From each study, the impact of NLR on the pCR, OR and HR, with their 95% CIs were extracted and combined using either a random or fixed-effects model. The results indicate that a higher pCR in patients with a low NLR (OR 1.620, 95% CI 1.209 to 2.169, p＜0.001). In addition, an elevated NLR predicted lower disease-free survival (HR 2.269, 95% CI 1.557 to 3.307, p<0.001) and overall survival (HR 1.691, 95% CI 1.365 to 2.096, p<0.001) in patients with breast cancer treated with NACT.

CONCLUSIONS

NLR is a suitable biomarker for predicting pCR and survival in patients with breast cancer receiving NACT.

Effects of Cadmium Exposure on the Immune System and Immunoregulation

Cadmium (Cd), a biologically non-essential heavy metal, is widespread in the environment, including the air, water, and soil, and is widely present in foods and quantum dot preparations. Cd enters the body primarily through inhalation and ingestion. Its biological half-life in humans is 10-35 years; therefore, Cd poses long-term health risks. While most studies on Cd toxicity have focused on organ and tissue damage, the immunotoxicity of Cd has drawn increasing attention recently. Cd accumulates in immune cells, modulates the function of the immune system, triggers immunological responses, and leads to diverse health problems. Cd acts as an immunotoxic agent by regulating the activity and apoptosis of immune cells, altering the secretion of immune cytokines, inducing reactive oxygen species (ROS) production and oxidative stress, changing the frequency of T lymphocyte subsets, and altering the production of selective antibodies in immune cells. This review summarizes the immunological toxicity of Cd, elucidates the mechanisms underlying Cd toxicity in terms of innate immunity and adaptive immunity, and discusses potential strategies to alleviate the adverse effects of Cd on the immune system.

Neutrophil extracellular traps in cancer

Beyond their well-known functions in the acute phases of the immune response, neutrophils play important roles in the various phases of tumor initiation and progression, through the release of their stored or newly synthesized mediators. In addition to reactive oxygen species, cytokines, chemokines, granule proteins and lipid mediators, neutrophil extracellular traps (NETs) can also be released upon neutrophil activation. NET formation can be achieved through a cell-death process or in association with the release of mitochondrial DNA from viable neutrophils. NETs are described as extracellular fibers of DNA and decorating proteins responsible for trapping and killing extracellular pathogens, playing a protective role in the antimicrobial defense. There is increasing evidence, however, that NETs play multiple roles in the scenario of cancer-related inflammation. For instance, NETs directly or indirectly promote tumor growth and progression, fostering tumor spread at distant sites and shielding cancer cells thus preventing the effects of cytotoxic lymphocytes. NETs can also promote tumor angiogenesis and cancer-associated thrombosis. On the other hand, there is some evidence that NETs may play anti-inflammatory and anti-tumorigenic roles. In this review, we focus on the main mechanisms underlying the emerging effects of NETs in cancer initiation and progression.

Nanomedicine-based strategies to target and modulate the tumor microenvironment

The interest in nanomedicine for cancer theranostics has grown significantly over the past few decades. However, these nanomedicines need to overcome several physiological barriers intrinsic to the tumor microenvironment (TME) before reaching their target. Intrinsic tumor genetic/phenotypic variations, along with intratumor heterogeneity, provide different cues to each cancer type, making each patient with cancer unique. This brings additional challenges in translating nanotechnology-based systems into clinically reliable therapies. To develop efficient therapeutic strategies, it is important to understand the dynamic interactions between TME players and the complex mechanisms involved, because they constitute invaluable targets to dismantle tumor progression. In this review, we discuss the latest nanotechnology-based strategies for cancer diagnosis and therapy as well as the potential targets for the design of future anticancer nanomedicines.

Tumor-associated myeloid cells: diversity and therapeutic targeting

Myeloid cells in tumor tissues constitute a dynamic immune population characterized by a non-uniform phenotype and diverse functional activities. Both tumor-associated macrophages (TAMs), which are more abundantly represented, and tumor-associated neutrophils (TANs) are known to sustain tumor cell growth and invasion, support neoangiogenesis and suppress anticancer adaptive immune responses. In recent decades, several therapeutic approaches have been implemented in preclinical cancer models to neutralize the tumor-promoting roles of both TAMs and TANs. Some of the most successful strategies have now reached the clinic and are being investigated in clinical trials. In this review, we provide an overview of the recent literature on the ever-growing complexity of the biology of TAMs and TANs and the development of the most promising approaches to target these populations therapeutically in cancer patients.