Neutrophils promote motility of cancer cells via a hyaluronan-mediated TLR4/PI3K activation loop

Immune Checkpoint Inhibitors and Immunosuppressive Tumor Microenvironment: Current Challenges and Strategies to Overcome Resistance

Immune checkpoint inhibitors (ICIs) are shown to improve cancer treatment effectiveness by boosting the immune system of the patient. Nevertheless, the unique and highly suppressive TME poses a significant challenge, causing heterogeneity of response or resistance in a considerable number of patients. This review focuses on the evasive attributes of the TME. Immune evasion mechanism in TME include immunosuppressive cells, cytokine and chemokine signaling, metabolic alterations and overexpression of immune checkpoint molecules such as PD-1, CTLA-4, LAG-3, TIM-3, TIGIT, BTLA and their interactions within the TME. In addition, this review focuses on the overcoming resistance by targeting immunosuppressive cells, normalizing tumor blood vessels, blocking two or three checkpoints simultaneously, combining vaccines, oncolytic viruses and metabolic inhibitors with ICIs or other therapies. This review also focuses on the necessity of finding predictive markers for the stratification of patients and to check response of ICIs treatment. It remains to be made certain by new research and intelligent innovations how these discoveries of the TME and its interplay facilitate ICI treatment and change the face of cancer treatment.

Mel4-coated hyaluronic acid-laden etafilcon A contact lenses: Improved wettability with retained antimicrobial properties

Soft contact lenses are a common mode of vision correction used worldwide. However, contact lens wearers often experience discomfort and are at risk of developing microbial infections. To address these issues, we designed Mel4-coated hyaluronic acid-laden etafilcon contact lenses to improve wettability while providing antimicrobial properties. The process involved the interaction of the etafilcon lens, which carries a net negative charge, with positively charged Mel4 (a cationic antimicrobial peptide). This was followed by interaction with hyaluronic acid (a negatively charged polymer). The components were then crosslinked using EDC-NHS [N-(3-dimethyl aminopropyl)-N'-ethyl carbodiimide hydrochloride and N-Hydroxy succinimide] to form amide bonds between the compounds and the lens. In this study, four batches of lenses were prepared: the first consisted of conventional HA-soaked lenses (SM-HA-L), the second consisted of lenses soaked in Mel4 and HA (SM-Mel4-HA-L), the third batch consisted of HA crosslinked with the lens (HA-Cr-L), and the fourth consisted of lenses soaked in Mel4 and HA, followed by crosslinking (Mel4-HA-Cr-L). During the washing and sterilization steps, SM-HA-L lenses showed high leaching compared to SM-Mel4-HA-L lenses, while HA-Cr-L and Mel4-HA-Cr-L lenses showed no leaching. A hyaluronidase breakdown assay revealed 5.37 μg, 9.28 μg, 8.04 μg, and 6.07 μg of HA per lens for SM-HA-L, SM-Mel4-HA-L, HA-Cr-L, and Mel4-HA-Cr-L, respectively. The wettability (contact angle) of SM-Mel4-HA-L lenses was improved compared to HA-Cr-L and Mel4-HA-Cr-L lenses. In vitro release studies showed no leaching of HA, indicating permanent entrapment or binding of HA to the contact lens surface. Both the SM-Mel4-HA-L lenses and crosslinked Mel4-HA-Cr-L lenses could significantly reduce the adhesion of Pseudomonas aeruginosa 6294 and Staphylococcus aureus 31 to the lenses. In conclusion, the presence of HA improved wettability, while Mel4 retained its antimicrobial activity, highlighting its potential to advance existing contact lens technology with improved wettability and antimicrobial properties.

Exosomes play a crucial role in remodeling the tumor microenvironment and in the treatment of gastric cancer

Gastric cancer (GC) is a common and frequent malignant cancer of the digestive system with a poor prognosis. In addition to common therapies such as surgical resection and chemotherapy, novel biological interventions are quite valuable for research. Exosomes are extracellular vesicles (EVs) that originate from various cell types and contain proteins, RNA, DNA, and other components that transmit biological signals and mediate intercellular communication. Numerous studies have shown that exosomes shape the tumor microenvironment (TME) by affecting hypoxia, inflammation, immunity, metabolism, and interstitial changes in the tumor, playing a crucial role in the development and metastasis of GC. This article reviews the important role of exosomes in the TME of GC and explores their potential clinical applications in GC treatment.

Toll-like Receptor 4 Signaling Mediates Gastritis and Gastric Cancer

The stomach is a crucial digestive organ in the human body, highly susceptible to inflammation or pathogen invasion, which can lead to various gastric diseases, including gastric cancer. Toll-like receptors (TLRs) are the first line of defense against pathogen invasion. TLR4, a member of the TLRs family, recognizes pathogen and danger-related molecular patterns to induce inflammatory responses. Helicobacter pylori (H. pylori) is a significant factor in gastric health, and TLR4 recognizes H. pylori -LPS to trigger an inflammatory response. Downstream TLR4 signaling generates proinflammatory cytokines that initiate inflammation in the gastric mucosa. In addition, TLR4 gene polymorphisms can increase health risks. This study aims to investigate the contribution of TLR4 to the inflammatory response in gastric diseases and the relation between TLR4 and H. pylori, TLR4 gene polymorphisms, and how TLR4 affects gastric diseases' possible pathways to provide further insight for future prevention and clinical treatment strategies.

Neutrophils in cancer: from biology to therapy

The view of neutrophils has shifted from simple phagocytic cells, whose main function is to kill pathogens, to very complex cells that are also involved in immune regulation and tissue repair. These cells are essential for maintaining and regaining tissue homeostasis. Neutrophils can be viewed as double-edged swords in a range of situations. The potent killing machinery necessary for immune responses to pathogens can easily lead to collateral damage to host tissues when inappropriately controlled. Furthermore, some subtypes of neutrophils are potent pathogen killers, whereas others are immunosuppressive or can aid in tissue healing. Finally, in tumor immunology, many examples of both protumorigenic and antitumorigenic properties of neutrophils have been described. This has important consequences for cancer therapy, as targeting neutrophils can lead to either suppressed or stimulated antitumor responses. This review will discuss the current knowledge regarding the pro- and antitumorigenic roles of neutrophils, leading to the concept of a confused state of neutrophil-driven pro-/antitumor responses.

Gamma-Glutamyl Transpeptidase to Neutrophil Ratio as Prognostic Indicator for Hepatocellular Carcinoma Patients Post-Curative Resection

Background

The close association between inflammation and the clinical outcomes of hepatocellular carcinoma (HCC) has been extensively documented. This study aims to analyze the association between a novel inflammatory indicator, the gamma-glutamyl transpeptidase to neutrophil ratio (GNR), and HCC prognosis following curative resection.

Methods

A cohort of 204 eligible HCC cases were included. Based on an optimal cut-off value determined utilizing the X-tile software, patients were categorized into low- and high-GNR groups. The overall survival (OS) and recurrence-free survival (RFS) rates were assessed using the Kaplan-Meier analysis method with Log rank tests. Multivariate Cox proportional hazard regression was used to investigate the independent association between GNR and HCC prognosis. Restricted cubic splines were used to explore the nonlinear relationship between GNR and the risk of death or recurrence.

Results

The low GNR group exhibited significantly higher 3-year OS and RFS rates than the high GNR group. Multivariate Cox analysis indicated that a high GNR level was independently associated with poor OS and RFS. A linear correlation between GNR and the risk of death, as well as a nonlinear inverted "U" shape correlation between GNR and the risk of recurrence, were observed.

Conclusion

The findings provide evidence supporting the independent association of GNR with HCC prognosis. These results offer promise for enhancing prognosis assessments and guiding active monitoring strategies for patients with HCC post-curative resection.

Using single-cell RNA sequencing and bulk RNA sequencing data to reveal a correlation between smoking and neutrophil activation in esophageal carcinoma patients

BACKGROUND

Cigarette smoking is considered as a major risk factor for esophageal carcinoma (ESCA) patients. Neutrophil activation plays a key role in cancer development and progression. However, the relationship between cigarette smoking and neutrophils in ESCA patients remained unclear.

METHODS

Single-cell RNA sequencing (scRNA-seq) and bulk RNA sequencing data were obtained from public databases. Uniform manifold approximation and projection (UMAP) was used to perform downscaling and clustering based on scRNA-seq data. The module genes associated with smoking in ESCA patients were filtered by weighted gene co-expression network analysis (WGCNA). Using the "AUCell" package, the enrichment of different cell subpopulations and gene collections were assessed. "CellChat" and "CellphoneDB" were used to infer the probability and significance of ligand-receptor interactions between different cell subpopulations.

RESULTS

WGCNA was performed to screened module genes associated with smoking in ESCA patients from MEdarkquosie, MEturquoise, and MEgreenyellow. Next, eight cell clusters were identified, and using the AUCell score, we determined that neutrophil clusters were more active in the gene modules associated with smoking in ESCA patients. Two neutrophil subtypes, Neutrophils 1 and Neutrophils 2, exhibited greater enrichment in inflammatory response regulation, intercellular adhesion, and regulation of T cell activation. Furthermore, we found that neutrophils may pass through AMPT-(ITGA5 + ITGB1) and ICAM1-AREG in order to promote the development of ESCA, and that the expression levels of the receptor genes insulin-degrading enzyme and ITGB1 were significantly and positively correlated with cigarette smoking per day.

CONCLUSION

Combining smoking-related gene modules and scRNA-seq, the current findings revealed the heterogeneity of neutrophils in ESCA and a tumor-promoting role of neutrophils in the tumor microenvironment of smoking ESCA patients.

Prognostic value of inflammatory markers NLR, PLR, and LMR in gastric cancer patients treated with immune checkpoint inhibitors: a meta-analysis and systematic review

Background

Immune checkpoint inhibitors (ICIs) represent a groundbreaking approach to cancer therapy. Inflammatory markers such as the neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and lymphocyte-to-monocyte ratio (LMR) have emerged as potential indicators strongly associated with tumor prognosis, albeit their prognostic significance remains contentious. The predictive value of NLR, PLR, LMR in patients with gastric cancer (GC) treated with ICIs has not been fully explored; therefore, we conducted a meta-analysis to examine the potential of inflammatory markers NLR, PLR, and LMR as survival predictors in this population.

Methods

A comprehensive search was conducted across PubMed, Embase, Web of Science, and Cochrane databases, with the search cut-off date set as March 2024. Hazard ratios (HR) and their corresponding 95% confidence intervals (CI) were calculated to assess the prognostic significance of NLR, PLR, and LMR for both progression-free survival (PFS) and overall survival (OS).

Results

Fifteen cohort studies involving 1336 gastric cancer patients were finally included in this meta-analysis. The results of the meta-analysis showed that high levels of NLR were associated with poorer OS and PFS in GC patients receiving ICIs, with combined HRs of OS [HR=2.01, 95%CI (1.72,2.34), P<0.01], and PFS PFS[HR=1.59, 95%CI (1.37,1.86), P<0.01], respectively; high levels of PLR were associated with poorer OS and PFS, and the combined HR was OS [HR=1.57, 95%CI (1.25,1.96), P<0.01], PFS [HR=1.52,95%CI (1.20, 1.94), P<0.01], respectively; and there was an association between elevated LMR and prolonged OS and PFS, and the combined HR was OS [HR=0.62, 95%CI (0.47,0.81), P<0.01], and PFS [HR=0.69, 95%CI (0.50,0.95), P<0.01].

Conclusion

In gastric cancer (GC) patients treated with immune checkpoint inhibitors (ICIs), elevated neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) were associated with poorer overall survival (OS) and progression-free survival (PFS), while high lymphocyte-to-monocyte ratio (LMR) was linked to improved OS and PFS. Subgroup analyses suggested that NLR might be particularly pertinent to the prognosis of GC patients. In conclusion, the inflammatory markers NLR, PLR, and LMR serve as effective biomarkers for prognostic assessment in GC patients, offering valuable insights for therapeutic decision-making in the realm of GC immunotherapy. Prospective studies of high quality are eagerly awaited to validate these findings in the future.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/#myprospero, identifier CRD42024524321.

Gastric cancer immunosuppressive microenvironment heterogeneity: implications for therapy development

Although immunotherapy has revolutionized solid tumor treatment, durable responses in gastric cancer (GC) remain limited. The heterogeneous tumor microenvironment (TME) facilitates immune evasion, contributing to resistance to conventional and immune therapies. Recent studies have highlighted how specific TME components in GC acquire immune escape capabilities through cancer-specific factors. Understanding the underlying molecular mechanisms and targeting the immunosuppressive TME will enhance immunotherapy efficacy and patient outcomes. This review summarizes recent advances in GC TME research and explores the role of the immune-suppressive system as a context-specific determinant. We also provide insights into potential treatments beyond checkpoint inhibition.

Multi-model analysis of gallbladder cancer reveals the role of OxLDL-absorbing neutrophils in promoting liver invasion

BACKGROUND

Gallbladder cancer (GBC) is the most common and lethal malignancy of the biliary tract that lacks effective therapy. In many GBC cases, infiltration into adjacent organs or distant metastasis happened long before the diagnosis, especially the direct liver invasion, which is the most common and unfavorable way of spreading.

METHODS

Single-cell RNA sequencing (scRNA-seq), spatial transcriptomics (ST), proteomics, and multiplexed immunohistochemistry (mIHC) were performed on GBC across multiple tumor stages to characterize the tumor microenvironment (TME), focusing specifically on the preferential enrichment of neutrophils in GBC liver invasion (GBC-LI).

RESULTS

Multi-model Analysis reveals the immunosuppressive TME of GBC-LI that was characterized by the enrichment of neutrophils at the invasive front. We identified the context-dependent transcriptional states of neutrophils, with the Tumor-Modifying state being associated with oxidized low-density lipoprotein (oxLDL) metabolism. In vitro assays showed that the direct cell-cell contact between GBC cells and neutrophils led to the drastic increase in oxLDL uptake of neutrophils, which was primarily mediated by the elevated OLR1 on neutrophils. The oxLDL-absorbing neutrophils displayed a higher potential to promote tumor invasion while demonstrating lower cancer cytotoxicity. Finally, we identified a neutrophil-promoting niche at the invasive front of GBC-LI that constituted of KRT17+ GBC cells, neutrophils, and surrounding fibroblasts, which may help cultivate the oxLDL-absorbing neutrophils.

CONCLUSIONS

Our study reveals the existence of a subset of pro-tumoral neutrophils with a unique ability to absorb oxLDL via OLR1, a phenomenon induced through cell-cell contact with KRT17+ GBC cells in GBC-LI.

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.

Prognostic significance and immune escape implication of tumor-infiltrating neutrophil plasticity in human head and neck squamous cell carcinoma

Tumor-infiltrating neutrophils play a crucial role in the progression of head and neck squamous cell carcinoma (HNSCC). Here, we aimed to statistically quantify the plasticity of HNSCC-infiltrating N2/N1 neutrophils and examine its impacts on survival and immune infiltration landscape. A retrospective study of 80 patients who underwent curative surgical resection for HNSCC between 2014 and 2017 was conducted in this study. HNSCC-infiltrating neutrophil phenotypes were classified using immunofluorescence staining, and the N2/N1 neutrophil plasticity was evaluated via the ratio of N2/N1 neutrophils. We then assessed the correlations between N2/N1 neutrophil plasticity, clinicopathological characteristics, and immune infiltration landscape using rigorous statistical methods. Infiltration variations of N1 and N2 neutrophils were observed between the tumor nest (TN) and tumor stroma (TS), with TN exhibiting higher N2 neutrophil infiltration and lower N1 neutrophil infiltration. High ratios of N2/N1 neutrophils were correlated with advanced TNM stage, large tumor size and invasion of adjacent tissue. High infiltration of N2 neutrophils was associated with decreased overall and relapse-free survival, which were opposite for N1 neutrophils. The independent prognostic role of N2/N1 neutrophil plasticity, particularly within the TN region, was confirmed by multivariate analyses. Moreover, the ratio of N2/N1 neutrophils within the TN region showed correlations with high CD8+ T cells infiltration and low FOXP3+ Tregs infiltration. We identify HNSCC-infiltrating N2/N1 neutrophil plasticity as a crucial prognostic indictor which potentially reflects the tumor microenvironment (TME) and immune escape landscape within HNSCC tissues. Further investigations and validations may provide novel therapeutic strategies for personalized immunomodulation in HNSCC patients.

Tumor associated neutrophils governs tumor progression through an IL-10/STAT3/PD-L1 feedback signaling loop in lung cancer

Tumor-associated neutrophils (TANs) can exist in either a pro-inflammatory or an anti-inflammatory state, known as N1 and N2, respectively. Anti-inflammatory TANs have been shown to correlate with poor prognosis and tumor progression in patients. To explore the role and mechanisms of TANs in lung cancer development, we isolated neutrophils from both peripheral blood and tumor tissues of patients/mice, and assessed their functional interaction with lung cancer cells both in vitro and in vivo. Our results revealed that tumor-derived neutrophils (or TANs) promote the tumorigenic and metastatic potential of lung cancer cells. Upon tumorigenesis, TANs display a N2-like status and secrete the cytokine IL-10 to facilitate the activation of c-Met/STAT3 signaling, which ultimately enhances distant metastasis in vivo. Meanwhile, the transcription factor STAT3 increases PD-L1 level in tumor cells, which promotes neutrophils polarization towards a N2-like status, leading to a positive feedback loop between TANs, IL-10, STAT3, PD-L1, and TANs themselves. Blocking IL-10, we additionally eliminated metastatic tumor nodules and enhanced the anticancer effects of chemotherapy in a Lewis mouse model. Our findings suggest a positive feedback loop between tumor cells and TANs that controls tumor progression and patient outcome in lung cancer.

Bcl-xL targeting eliminates ageing tumor-promoting neutrophils and inhibits lung tumor growth

Elevated peripheral blood and tumor-infiltrating neutrophils are often associated with a poor patient prognosis. However, therapeutic strategies to target these cells are difficult to implement due to the life-threatening risk of neutropenia. In a genetically engineered mouse model of lung adenocarcinoma, tumor-associated neutrophils (TAN) demonstrate tumor-supportive capacities and have a prolonged lifespan compared to circulating neutrophils. Here, we show that tumor cell-derived GM-CSF triggers the expression of the anti-apoptotic Bcl-xL protein and enhances neutrophil survival through JAK/STAT signaling. Targeting Bcl-xL activity with a specific BH3 mimetic, A-1331852, blocked the induced neutrophil survival without impacting their normal lifespan. Specifically, oral administration with A-1331852 decreased TAN survival and abundance, and reduced tumor growth without causing neutropenia. We also show that G-CSF, a drug used to combat neutropenia in patients receiving chemotherapy, increased the proportion of young TANs and augmented the anti-tumor effect resulting from Bcl-xL blockade. Finally, our human tumor data indicate the same role for Bcl-xL on pro-tumoral neutrophil survival. These results altogether provide preclinical evidence for safe neutrophil targeting based on their aberrant intra-tumor longevity.

Immune microenvironment of cervical cancer and the role of IL-2 in tumor promotion

The tumor microenvironment (TME) is a heterogeneous mixture of resident and tumor cells that maintain close communication through their secretion products. The composition of the TME is dynamic and complex among the different types of cancer, where the immune cells play a relevant role in the elimination of tumor cells, however, under certain circumstances they contribute to tumor development. In cervical cancer (CC) the human papilloma virus (HPV) shapes the microenvironment in order to mediate persistent infections that favors transformation and tumor development. Interleukin-2 (IL-2) is an important TME cytokine that induces CD8+ effector T cells and NKs to eliminate tumor cells, however, IL-2 can also suppress the immune response through Treg cells. Recent studies have shown that CC cells express the IL-2 receptor (IL-2R), that are induced to proliferate at low concentrations of exogenous IL-2 through alterations in the JAK/STAT pathway. This review provides an overview of the main immune cells that make up the TME in CC, as well as the participation of IL-2 in the tumor promotion. Finally, it is proposed that the low density of IL-2 produced by immunocompetent cells is used by tumor cells through its IL-2R as a mechanism to proliferate simultaneously depleting this molecule in order to evade immune response.

EFHD1 expression is correlated with tumor-infiltrating neutrophils and predicts prognosis in gastric cancer

Background

Gastric cancer (GC) ranks third in terms of mortality worldwide. The tumor microenvironment is critical for the progression of gastric cancer. This study investigated the association between EF-hand domain containing 1 (EFHD1) expression and its clinical significance in the tumor microenvironment (TME) of gastric cancer.

Methods

We used bioinformatic analyses to assess the relevance of EFHD1 mRNA in the TME of gastric carcinoma tissues and its relationship with clinical features. Therefore, we performed multiplex immunohistochemistry analyses to determine the potential role of the EFHD1 protein in the TME of gastric cancer.

Results

EFHD1 expression increased dramatically in gastric cancer tissues compared to levels in non-cancerous tissue samples (t = 6.246, P < 0.001). The EFHD1 protein presentation was associated with invasion depth (χ2 = 19.120, P < 0.001) and TNM stages (χ2 = 14.468, P = 0.002). Notably, EFHD1 protein expression was significantly related to CD66b + neutrophil infiltration of the intratumoral (r = 0.420, P < 0.001) and stromal (r = 0.367, P < 0.001) TME in gastric cancer. Additionally, Cox regression analysis revealed that EFHD1 was an independent prognostic predictor (hazard ratio [HR] = 2.262, P < 0.001) in patients with gastric cancer.

Conclusions

Our study revealed the pattern of EFHD1 overexpression in the TME of patients with gastric cancer and demonstrated its utility as a biomarker for unfavorable clinical outcomes, thereby providing a potential immunotherapy target.

Tumor necrosis factor-α-inducible protein 8-like protein 3 (TIPE3): a novel prognostic factor in colorectal cancer

BACKGROUND

To explore the correlation of tumor necrosis factor-α-induced protein 8-like protein 3 (TIPE3) expressions in colorectal cancer (CRC) with tumor-immune infiltration and patient prognosis.

METHODS

Formalin-fixed paraffin-embedded tumor samples from CRC patients (n = 110) were used in this study. Immunohistochemistry staining of TIPE3 and three prognostic immune biomarkers (CD8, CD20, and CD66b) was conducted in the tumor tissues and adjacent normal tissues. A Cox regression analysis of univariate and multivariate variables was performed to assess the correlation between TIPE3 and patient prognosis.

RESULT

We found that TIPE3 was mainly expressed in the cytoplasm, with a small amount in the nucleus. The expression of TIPE3 in tumor tissues is significantly higher than in adjacent normal tissues, and it is significantly correlated with the survival rate of patients in tumor tissues (p = 0.0038) and adjacent normal tissues (p<0.0001). Patients with a high TIPE3 expression had a lower survival rate, while patients with a low TIPE3 expression had a higher survival rate. Univariate regression analysis showed that the TIPE3 expression in tumor tissues (p = 0.007), the TIPE3 expression in adjacent normal tissues (p<0.001), the number of CD8+ T cells in tumor tissues (p = 0.020), the number of CD20+ B cells in tumor tissues (p = 0.023), the number of CD20+ B cells in adjacent normal tissues (p = 0.023), the number of CD66b+ neutrophils in tumor tissues (p = 0.005), the number of CD66b+ neutrophils in adjacent normal tissues (p<0.001), lymphatic metastasis (p = 0.010), TNM stage (p = 0.013), and tumor grade (p = 0.027) were significantly correlated with overall survival (OS). These prognostic factors were then subjected to multivariate regression analysis, and the results showed that the expression of TIPE3, the number of CD8+ T cells, and the number of CD66b+ neutrophils were prognostic factors affecting the OS rate of CRC patients.

CONCLUSION

We found that the TIPE3 protein is upregulated in CRC cancer tissues and is correlated with survival rate.

Interplay between tumor-derived factors and tumor-associated neutrophils: opportunities for therapeutic interventions in cancer

Neutrophils have emerged as important players in the tumor microenvironment, largely attributed to their plasticity and heterogeneity. Evidence accumulated thus far indicates that neutrophils signaled by external cues can promote tumor progression via several mechanisms. Hence, in our quest to target tumor-associated neutrophils to improve treatment, understanding the mechanisms by which tumor-derived factors regulate neutrophils to gain pro-tumor functions and the feedback loop by which these neutrophils promote tumor progression is very crucial. Herein, we review the published data on how tumor-derived factors alter neutrophils phenotype to promote tumor progression with particular emphasis on immunosuppression, autophagy, angiogenesis, tumor proliferation, metastasis, and therapeutic resistance. These deeper insights could provide a wider view and novel therapeutic approach to neutrophil-targeted therapy in cancer.

Role of Annexin A1 Secreted by Neutrophils in Melanoma Metastasis

Annexin A1 (AnxA1) is highly secreted by neutrophils and binds to formyl peptide receptors (FPRs) to trigger anti-inflammatory effects and efferocytosis. AnxA1 is also expressed in the tumor microenvironment, being mainly attributed to cancer cells. As recruited neutrophils are player cells at the tumor sites, the role of neutrophil-derived AnxA1 in lung melanoma metastasis was investigated here. Melanoma cells and neutrophils expressing AnxA1 were detected in biopsies from primary melanoma patients, which also presented higher levels of serum AnxA1 and augmented neutrophil-lymphocyte ratio (NLR) in the blood. Lung melanoma metastatic mice (C57BL/6; i.v. injected B16F10 cells) showed neutrophilia, elevated AnxA1 serum levels, and higher labeling for AnxA1 in neutrophils than in tumor cells at the lungs with metastasis. Peritoneal neutrophils collected from naïve mice were co-cultured with B16F10 cells or employed to obtain neutrophil-conditioned medium (NCM; 18 h incubation). B16F10 cells co-cultured with neutrophils or with NCM presented higher invasion, which was abolished if B16F10 cells were previously incubated with FPR antagonists or co-cultured with AnxA1 knockout (AnxA1^-/-) neutrophils. The depletion of peripheral neutrophils during lung melanoma metastasis development (anti-Gr1; i.p. every 48 h for 21 days) reduced the number of metastases and AnxA1 serum levels in mice. Our findings show that AnxA1 secreted by neutrophils favors melanoma metastasis evolution via FPR pathways, addressing AnxA1 as a potential biomarker for the detection or progression of melanoma.

Hyaluronic Acid as a Modern Approach in Anticancer Therapy-Review

Hyaluronic acid (HA) is a linear polysaccharide and crucial component of the extracellular matrix (ECM), maintaining tissue hydration and tension. Moreover, HA contributes to embryonic development, healing, inflammation, and cancerogenesis. This review summarizes new research on the metabolism and interactions of HA with its binding proteins, known as hyaladherins (CD44, RHAMM), revealing the molecular basis for its distinct biological function in the development of cancer. The presence of HA on the surface of tumor cells is a sign of an adverse prognosis. The involvement of HA in malignancy has been extensively investigated using cancer-free naked mole rats as a model. The HA metabolic components are examined for their potential impact on promoting or inhibiting tumor formation, proliferation, invasion, and metastatic spread. High molecular weight HA is associated with homeostasis and protective action due to its ability to preserve tissue integrity. In contrast, low molecular weight HA indicates a pathological condition in the tissue and plays a role in pro-oncogenic activity. A systematic approach might uncover processes related to cancer growth, establish novel prognostic indicators, and identify potential targets for treatment action.

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

Research on tumor-associated neutrophils (TAN) currently surges because of the well-documented strong clinical relevance of tumor-infiltrating neutrophils. This relevance is illustrated by strong correlations between high frequencies of intratumoral neutrophils and poor outcome in the majority of human cancers. Recent high-dimensional analysis of murine neutrophils provides evidence for unexpected plasticity of neutrophils in murine models of cancer and other inflammatory non-malignant diseases. New analysis tools enable deeper insight into the process of neutrophil differentiation and maturation. These technological and scientific developments led to the description of an ever-increasing number of distinct transcriptional states and associated phenotypes in murine models of disease and more recently also in humans. At present, functional validation of these different transcriptional states and potential phenotypes in cancer is lacking. Current functional concepts on neutrophils in cancer rely mainly on the myeloid-derived suppressor cell (MDSC) concept and the dichotomous and simple N1-N2 paradigm. In this manuscript, we review the historic development of those concepts, critically evaluate these concepts against the background of our own work and provide suggestions for a refinement of current concepts in order to facilitate the transition of TAN research from experimental insight to clinical translation.

Tumor-associated neutrophils and neutrophil-targeted cancer therapies

Neutrophils are the frontline cells in response to microbial infections and are involved in a range of inflammatory disorders in the body. In recent years, neutrophils have gained considerable attention in their involvement of complex roles in tumor development and progression. Tumor-associated neutrophils (TANs) that accumulate in local region could be triggered by external stimuli from tumor microenvironment (TME) and switch between anti- and pro-tumor phenotypes. The anti-tumor neutrophils kill tumor cells through direct cytotoxic effects as well as indirect effects by activating adaptive immune responses. In contrast, the pro-tumor phenotype of neutrophils might be associated with cell proliferation, angiogenesis, and immunosuppression in TME. More recently, neutrophils have been proposed as a potential target in cancer therapy for their ability to diminish the pro-tumor pathways, such as by immune checkpoint blockade. This review discusses the complex roles of neutrophils in TME and highlights the strategies in neutrophil targeting in cancer treatment with a particular focus on the progresses of ongoing clinical trials involving neutrophil-targeted therapies.

Neutrophils Promote Glioblastoma Tumor Cell Migration after Biopsy

Glioblastoma is diagnosed by biopsy or, if clinically feasible, tumor resection. However, emerging evidence suggests that this surgical intervention may increase the risk of tumor cell spread. It has been hypothesized that the damage to the tumor leads to infiltration of immune cells that consequently form an environment that favors tumor cell motility. In mouse glioma models, it was previously found that biopsy induced migration of tumor cells in vivo and that recruitment of monocytes from the blood was involved in this effect. However, the role of neutrophils in this process is still unclear. Here, we study the contribution of neutrophils on the pro-migratory effect of surgical interventions in glioma. Using repetitive intravital microscopy, in vivo migration of glioma tumor cells before and after biopsy was compared in mice systemically depleted of neutrophils. Interestingly, macrophages/microglia were almost completely absent from neutrophil-depleted tumors, indicating that neutrophils may be indirectly involved in biopsy-induced migration of glioma tumor cells through the recruitment of macrophages to the tumor. To further investigate whether neutrophils have the potential to also directly promote glioblastoma tumor cell migration, we performed in vitro migration assays using human neutrophils. Indeed, wound-healing of human primary glioblastoma tumor cell lines was promoted by human neutrophils. The pro-migratory effects of human neutrophils on glioblastoma tumor cells could also be recapitulated in transwell migration assays, indicating that soluble factor(s) are involved. We therefore provide evidence for both an indirect and direct involvement of neutrophils in tumor spread following biopsy of glioblastoma tumors.

Neutrophils as potential therapeutic targets in hepatocellular carcinoma

The success of atezolizumab plus bevacizumab treatment contributed to a shift in systemic therapies for hepatocellular carcinoma (HCC) towards combinations that include cancer immunotherapeutic agents. Thus far, the principal focus of cancer immunotherapy has been on interrupting immune checkpoints that suppress antitumour lymphocytes. As well as lymphocytes, the HCC environment includes numerous other immune cell types, among which neutrophils are emerging as an important contributor to the pathogenesis of HCC. A growing body of evidence supports neutrophils as key mediators of the immunosuppressive environment in which some cancers develop, as well as drivers of tumour progression. If neutrophils have a similar role in HCC, approaches that target or manipulate neutrophils might have therapeutic benefits, potentially including sensitization of tumours to conventional immunotherapy. Several neutrophil-directed therapies for patients with HCC (and other cancers) are now entering clinical trials. This Review outlines the evidence in support of neutrophils as drivers of HCC and details their mechanistic roles in development, progression and metastasis, highlighting the reasons that neutrophils are well worth investigating despite the challenges associated with studying them. Neutrophil-modulating anticancer therapies entering clinical trials are also summarized.

Peritumoral CD16b positive-neutrophil accumulation strongly correlates with regional lymph node metastasis in thoracic esophageal squamous cell cancer

BACKGROUND

The mechanism underlying cancer cell metastasis from the tumor to regional lymph nodes is not yet fully understood. We hypothesized that peritumoral neutrophil accumulation promotes regional lymph node metastasis in thoracic esophageal squamous cell cancer.

METHODS

Between 2010 and 2019, 126 thoracic esophageal squamous cell cancer patients received curative (R0) esophagectomy without preoperative treatment in our hospital. Using paraffin-embedded resected tumors, we performed immunohistochemical analysis of CD16b-positive neutrophil accumulation in the peritumoral area, which was defined as a 1-mm region centered on the border separating the malignant cell nests from the host tissue. The relationship between the density of peritumoral CD16b staining and pathological lymph node metastasis or 5-year overall survival was evaluated.

RESULTS

Although the clinicopathological characteristics of CD16b-high and CD16b-low patients did not differ, greater pathological lymph node metastasis (P < .001) and lymphatic invasion by the tumor (P = .024) and a poorer 5-year survival (P = .010) were seen in CD16b-high patients. Moreover, CD16b-positive neutrophil density was generally higher in the peritumoral area than within the tumor itself. Univariate and multivariate analyses showed that CD16b-positive neutrophil accumulation was an independent factor for lymph node metastasis with an odds ratio >25 (P < .001). On the other hand, blood neutrophil counts did not correlate with lymph node metastasis.

CONCLUSION

Peritumoral accumulation of CD16b-positive neutrophils is an independent factor strongly correlated with lymph node metastasis in thoracic esophageal squamous cell cancer.

Neutrophils: Driving inflammation during the development of hepatocellular carcinoma

The relationship between immune and inflammatory responses in hepatocellular carcinoma (HCC) has garnered significant interest. In the peripheral blood and tumour microenvironment (TME), neutrophils, which are innate immune cells, crucially respond to various inflammatory factors, leading to tumour progression. To some extent, they affect the clinical treatment strategy and survival among HCC patients. A high circulating neutrophil-to-lymphocyte ratio is a reliable factor that can be used to predict poor outcomes in HCC patients. However, the mechanisms underlying the protumoural effects of circulating neutrophils remain poorly understood. Besides, the distinct role and function of neutrophils at the site of HCC remain relatively unclear, which is partially attributed to their substantial heterogeneity compared with other immune cells. In this review, we firstly discuss the current information available, detailing distinct subsets, functional phenotypes, and the impact of circulating and tumour-infiltrating neutrophils on tumourigenesis in HCC. Furthermore, we describe recent pre-clinical and clinical studies concerning neutrophils for evaluating the feasibility of targeting diverse protumoural aspects to improve therapeutic efficacy, thus paving the way for neutrophil-based treatment, especially in combination with immunotherapy.

Impact of immune cells on the hallmarks of cancer: A literature review

Tumor-infiltrating immune cells (TIICs) are critical players in the tumor microenvironment, modulating cancer cell functions. TIICs are highly heterogenic and plastic and may either suppress cancers or provide support for tumor growth. A wide range of studies have shed light on how tumor-associated macrophages, dendritic cells, neutrophils, mast cells, natural killer cells and lymphocytes contribute for the establishment of several hallmarks of cancer and became the basis for successful immunotherapies. Many of those TIICs play pivotal roles in several hallmarks of cancer. This review contributes to elucidate the multifaceted roles of immune cells in cancer development, highlighting molecular components that constitute promising therapeutic targets. Additional studies are needed to clarify the relation between TIICs and hallmarks such as enabling replicative immortality, evading growth suppressors, sustaining proliferative signaling, resisting cell death and genome instability and mutation, to further explore their therapeutic potential and improve the outcomes of cancer patients.

Probiotics in Counteracting the Role of Neutrophils in Cancer Metastasis

Neutrophils are known for their role geared towards pathogen clearance by different mechanisms that they initiate, primarily by the release of neutrophil extracellular traps (NETs). However, their immune-surveillance capacity accompanied with plasticity in existing as interchangeable subsets, discovered recently, has revealed their property to contribute to complex cancer pathologies including tumor initiation, growth, angiogenesis and metastasis. Although there is a growing body of evidence suggesting a critical balance between the protumoral and antitumoral neutrophil phenotypes, an in-depth signaling pathway analysis would aid in determination of anticipatory, diagnostic and therapeutic targets. This review presents a comprehensive overview of the potential pathways involved in neutrophil-triggered cancer metastasis and introduces the influence of the microbial load and avenues for probiotic intervention.

Prognostic Utility of Pretreatment Neutrophil-Lymphocyte Ratio in Advanced Larynx Cancer

Purpose:

Neutrophil-lymphocyte ratio has been explored as a prognosticator in several cancer types, but its association with larynx cancer outcomes is not well known. We aimed to identify an optimal NLR cutoff point and examine the prognostic utility of this biomarker in patients with locoregionally advanced larynx cancer treated with curative intent.

Methods:

In the Veterans Affairs’ (VA) national database, we identified patients with locoregionally advanced (T3-4N0-3M0) laryngeal squamous cell carcinoma diagnosed between 2000 and 2017 and treated with curative intent. NLR cutoff points were calculated using Contal/O’Quigley’s method. Outcomes of larynx cancer-specific survival (CSS), overall survival (OS), and non-larynx cancer survival (NCS) were evaluated in multivariable Cox and Fine-Gray models.

Results:

In 1047 patients, the optimal pretreatment NLR cutoff was identified as 4.17 - 722 patients with NLR ⩽ 4.17, 325 patients with NLR > 4.17. The elevated NLR cohort had a higher proportion of T4 disease (39.4% vs 28.4%), node positive disease (52.3% vs 43.1%), and surgical treatment (43.7% vs 35.2%). In multivariable analysis, NLR > 4.17 was independently associated with worse OS (HR 1.31, 95% CI 1.12-1.54, P = .001) and worse CSS (HR 1.46, 95% CI 1.17-1.83, P < .001), but not with NCS (HR 0.94, 95% CI 0.75-1.18, P = .58).

Conclusion:

In locoregionally advanced larynx cancer treated with curative intent, we identified elevated NLR to be associated with inferior OS and CSS. Further prospective studies are needed to investigate pretreatment NLR and our identified 4.17 cutoff as a potential larynx cancer-specific marker for this high risk population.

Leveling Up the Controversial Role of Neutrophils in Cancer: When the Complexity Becomes Entangled

Neutrophils are the most abundant immune cell in the circulation of human and act as gatekeepers to discard foreign elements that have entered the body. They are essential in initiating immune responses for eliminating invaders, such as microorganisms and alien particles, as well as to act as immune surveyors of cancer cells, especially during the initial stages of carcinogenesis and for eliminating single metastatic cells in the circulation and in the premetastatic organs. Since neutrophils can secrete a whole range of factors stored in their many granules as well as produce reactive oxygen and nitrogen species upon stimulation, neutrophils may directly or indirectly affect carcinogenesis in both the positive and negative directions. An intricate crosstalk between tumor cells, neutrophils, other immune cells and stromal cells in the microenvironment modulates neutrophil function resulting in both anti- and pro-tumor activities. Both the anti-tumor and pro-tumor activities require chemoattraction towards the tumor cells, neutrophil activation and ROS production. Divergence is seen in other neutrophil properties, including differential secretory repertoire and membrane receptor display. Many of the direct effects of neutrophils on tumor growth and metastases are dependent on tight neutrophil–tumor cell interactions. Among them, the neutrophil Mac-1 interaction with tumor ICAM-1 and the neutrophil L-selectin interaction with tumor-cell sialomucins were found to be involved in the neutrophil-mediated capturing of circulating tumor cells resulting in increased metastatic seeding. On the other hand, the anti-tumor function of neutrophils was found to rely on the interaction between tumor-surface-expressed receptor for advanced glycation end products (RAGE) and Cathepsin G expressed on the neutrophil surface. Intriguingly, these two molecules are also involved in the promotion of tumor growth and metastases. RAGE is upregulated during early inflammation-induced carcinogenesis and was found to be important for sustaining tumor growth and homing at metastatic sites. Cathepsin G was found to be essential for neutrophil-supported lung colonization of cancer cells. These data level up the complexity of the dual role of neutrophils in cancer.

Exosome-derived noncoding RNAs in gastric cancer: functions and clinical applications

Exosomes are a subpopulation of the tumour microenvironment (TME) that transmit various biological molecules to promote intercellular communication. Exosomes are derived from nearly all types of cells and exist in all body fluids. Noncoding RNAs (ncRNAs) are among the most abundant contents in exosomes, and some ncRNAs with biological functions are specifically packaged into exosomes. Recent studies have revealed that exosome-derived ncRNAs play crucial roles in the tumorigenesis, progression and drug resistance of gastric cancer (GC). In addition, regulating the expression levels of exosomal ncRNAs can promote or suppress GC progression. Moreover, the membrane structures of exosomes protect ncRNAs from degradation by enzymes and other chemical substances, significantly increasing the stability of exosomal ncRNAs. Specific hallmarks within exosomes that can be used for exosome identification, and specific contents can be used to determine their origin. Therefore, exosomal ncRNAs are suitable for use as diagnostic and prognostic biomarkers or therapeutic targets. Regulating the biogenesis of exosomes and the expression levels of exosomal ncRNAs may represent a new way to block or eradicate GC. In this review, we summarized the origins and characteristics of exosomes and analysed the association between exosomal ncRNAs and GC development.

Neutrophil extracellular traps promote gastric cancer metastasis by inducing epithelial‑mesenchymal transition

The risks of tumor recurrence following the successful resection of the primary tumor have been known for decades; however, the precise mechanisms underlying treatment failures remain unknown. The formation of neutrophil extracellular traps (NETs) has increasingly been demonstrated to be associated with thrombi formation in cancer patients, as well as with the development and metastasis of cancer. The present study demonstrated that the level of peripheral blood NETs in patients with gastric cancer (GC) was associated with tumor progression, and patients with stage III/IV disease exhibited significant differences compared with the healthy controls and patients with stage I/II disease, which may be associated with an increased risk of metastasis. In addition, plasma from patients with stage III/IV GC was more prone to stimulate neutrophils to form NETs; thus, it was hypothesized that the formation of NETs may be affected by the tumor microenvironment. A higher deposition of NETs in GC tissues compared with normal resection margins was also identified. In vitro, following treatment with phorbol myristate acetate, which promotes the formation of NETs, or with DNAse-1/GSK-484, which inhibits the formation of NETs, it was found that the tumor migratory ability was altered; however, no significant changes were observed in cell proliferation and cell cycle progression. Epithelial-mesenchymal transition (EMT) is a key event associated with dissemination and metastasis in GC pathogenesis. Finally, the present study demonstrated that NETs promote a more aggressive mesenchymal phenotype and promote the progression of GC in vitro and in vivo. On the whole, to the best of our knowledge, the present study reports a previously unknown role of NETs in the regulation of GC, which is associated with EMT and migration. Therefore, targeting NETs may prove to be therapeutically beneficial.

Prognostic utility of pretreatment neutrophil-lymphocyte ratio in survival outcomes in localized non-small cell lung cancer patients treated with stereotactic body radiotherapy: Selection of an ideal clinical cutoff point

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Neutrophil-lymphocyte ratio is a promising prognostic marker for several cancers.

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NLR is not useful as a marker of lung cancer survival in localized lung cancer.

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NLR has potential as a marker of competing mortality risk in localized lung cancer.

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NLR cutoff of 4.0 is proposed as a clinically useful cutoff point.

Background and purpose

Neutrophil-lymphocyte ratio (NLR) has been associated with overall survival (OS) in non-small cell lung cancer (NSCLC). We aimed to assess the utility of NLR as a predictor of lung cancer-specific survival (LCS) and identify an optimal, pretreatment cutoff point in patients with localized NSCLC treated with stereotactic body radiotherapy (SBRT) within the Veterans Affairs’ (VA) national database.

Materials and methods

In the VA database, we identified patients with biopsy-proven, clinical stage I NSCLC treated with SBRT between 2006 and 2015. Cutoff points for NLR were calculated using Contal/O’Quigley’s and Cox Wald methods. Primary outcomes of OS, LCS, and non-lung cancer survival (NCS) were evaluated in Cox and Fine-Gray models.

Results

In 389 patients, optimal NLR cutoff was identified as 4.0. In multivariable models, NLR > 4.0 was associated with decreased OS (HR 1.44, p = 0.01) and NCS (HR 1.68, p = 0.01) but not with LCS (HR 1.32, p = 0.09). In a subset analysis of 229 patients with pulmonary function tests, NLR > 4.0 remained associated with worse OS (HR 1.51, p = 0.02) and NCS (HR 2.18, p = 0.01) while the association with LCS decreased further (HR 1.22, p = 0.39).

Conclusion

NLR was associated with worse OS in patients with localized NSCLC treated with SBRT; however, NLR was only associated with NCS and not with LCS. Pretreatment NLR, with a cutoff of 4.0, offers potential as a marker of competing mortality risk which can aid in risk stratification in this typically frail and comorbid population. Further studies are needed to validate pretreatment NLR as a clinical tool in this setting.

Granulocytes and Cells of Granulocyte Origin-The Relevant Players in Colorectal Cancer

Colorectal cancer (CRC) is one of the most common malignancy and cause of cancer death worldwide, and it still remains a therapeutic challenge for western medicine. There is strong evidence that, in addition to genetic predispositions, environmental factors have also a substantial impact in CRC development. The risk of CRC is attributed, among others to dietary habits, alcohol consumption, whereas physical activity, food containing dietary fiber, dairy products, and calcium supplements have a protective effect. Despite progress in the available therapies, surgery remains a basic treatment option for CRC. Implementation of additional methods of treatment such as chemo- and/or targeted immunotherapy, improved survival rates, however, the results are still far from satisfactory. One of the reasons may be the lack of deeper understanding of the interactions between the tumor and different types of cells, including tumor infiltrating granulocytes. While the role of neutrophils is quite well explored in many cancers, role of eosinophils and basophils is often underestimated. As part of this review, we focused on the function of different granulocyte subsets in CRC, emphasizing the beneficial role of eosinophils and basophils, as well as dichotomic mode of neutrophils action. In addition, we addressed the current knowledge on cells of granulocyte origin, specifically granulocytic myeloid derived suppressor cells (Gr-MDSCs) and their role in development and progression of CRC.

Neutrophil-to-lymphocyte ratio correlates with prognosis and response to chemotherapy in patients with non-M3 de novo acute myeloid leukemia

Background

Neutrophil-to-lymphocyte (NLR) ratio can predict survival outcome and assess response to chemotherapy in several tumors. However, the values of NLR in acute myeloid leukemia (AML) remains unknown.

Methods

A retrospective review of 181 patients with de novo AML excluding acute promyelocytic leukemia (M3) was conducted in our institute. We categorized the patients into two groups by defining NLR =2.0 as the cut-off point. NLR was calculated by the ratio of the number of neutrophils to lymphocytes in the peripheral blood (PB). The baseline clinicopathologic parameters were compared using Chi-squared test or Kruskal-Wallis H test. Kaplan-Meier analysis was used to assess survival, and overall survival (OS) and disease-free survival (DFS) were analyzed using the Cox regression with log-rank tests.

Results

We found AML patients with low NLR (<2.0) had longer OS and DFS than those with high NLR (≥2.0). NLR, absolute neutrophil count (ANC), and absolute lymphocyte count (ALC) were significantly associated with OS and DFS in all AML patients. NLR, ANC, and ALC were associated with OS and DFS only in those case with myeloblasts over 50% in bone marrow (BM). Furthermore, the median NLR was dramatically increased in low NLR group when patients achieved complete remission (CR).

Conclusions

Pretreatment NLR as a marker can predict the prognosis and NLR can assess the response to chemotherapy in patients with non-M3 AML, especially in those cases with myeloblasts over 50% in BM.

Neutrophils as Orchestrators in Tumor Development and Metastasis Formation

Several lines of clinical and experimental evidence suggest that immune cell plasticity is a central player in tumorigenesis, tumor progression, and metastasis formation. Neutrophils are able to promote or inhibit tumor growth. Through their interaction with tumor cells or their crosstalk with other immune cell subsets in the tumor microenvironment, they modulate tumor cell survival. Here, we summarize current knowledge with regards to the mechanisms that underlie neutrophil–mediated effects on tumor establishment and metastasis development. We also discuss the tumor-mediated effects on granulopoiesis and neutrophil precursors in the bone marrow and the involvement of neutrophils in anti-tumor therapeutic modalities.

Cell Migration Guided by Cell-Cell Contacts in Innate Immunity

The directed migration of leukocytes to sites of damage or infection is necessary for a productive immune response. There is substantial evidence supporting a key role for chemoattractants in directed migration, however, less is known about how cell-cell contacts affect the migratory behavior of leukocytes in innate immunity. Here, we explore how cell-cell contacts can affect the directed migration of innate immune cells, including their role in attracting, repelling, or stopping cell motility. Further investigation of cell contact dynamics as guidance cues may yield new insights into the regulation of innate immunity.

Tumor-Associated Neutrophils and Macrophages-Heterogenous but Not Chaotic

Tumor-associated macrophages (TAMs) and tumor-associated neutrophils (TANs) have been extensively studied. Their pleotropic roles were observed in multiple steps of tumor progression and metastasis, and sometimes appeared to be inconsistent across different studies. In this review, we collectively discussed many lines of evidence supporting the mutual influence between cancer cells and TAMs/TANs. We focused on how direct interactions among these cells dictate co-evolution involving not only clonal competition of cancer cells, but also landscape shift of the entire tumor microenvironment (TME). This co-evolution may take distinct paths and contribute to the heterogeneity of cancer cells and immune cells across different tumors. A more in-depth understanding of the cancer-TAM/TAN co-evolution will shed light on the development of TME that mediates metastasis and therapeutic resistance.

Atypical immunometabolism and metabolic reprogramming in liver cancer: Deciphering the role of gut microbiome

Hepatocellular carcinoma (HCC) is the fourth leading cause of cancer-related mortality worldwide. Much recent research has delved into understanding the underlying molecular mechanisms of HCC pathogenesis, which has revealed to be heterogenous and complex. Two major hallmarks of HCC include: (i) a hijacked immunometabolism and (ii) a reprogramming in metabolic processes. We posit that the gut microbiota is a third component in an entanglement triangle contributing to HCC progression. Besides metagenomic studies highlighting the diagnostic potential in the gut microbiota profile, recent research is pinpointing the gut microbiota as an instigator, not just a mere bystander, in HCC. In this chapter, we discuss mechanistic insights on atypical immunometabolism and metabolic reprogramming in HCC, including the examination of tumor-associated macrophages and neutrophils, tumor-infiltrating lymphocytes (e.g., T-cell exhaustion, regulatory T-cells, natural killer T-cells), the Warburg effect, rewiring of the tricarboxylic acid cycle, and glutamine addiction. We further discuss the potential involvement of the gut microbiota in these characteristics of hepatocarcinogenesis. An immediate highlight is that microbiota metabolites (e.g., short chain fatty acids, secondary bile acids) can impair anti-tumor responses, which aggravates HCC. Lastly, we describe the rising 'new era' of immunotherapies (e.g., immune checkpoint inhibitors, adoptive T-cell transfer) and discuss for the potential incorporation of gut microbiota targeted therapeutics (e.g., probiotics, fecal microbiota transplantation) to alleviate HCC. Altogether, this chapter invigorates for continuous research to decipher the role of gut microbiome in HCC from its influence on immunometabolism and metabolic reprogramming.

LDGs versus NDGs in patients with oral squamous cell carcinoma (OSCC)

BACKGROUND

The significant role played by neutrophils in cancer biology is indisputable; yet, their subpopulations may exhibit a contrasting role. The phenomenon of polarization of neutrophils and signaling modulators in the course of a neoplastic process has gained increased attention in recent times. The present study's objective was to quantitatively assess low-density neutrophils (LDNs) and normal-density neutrophils (NDNs) populations including IL-17 expression in confrontation with Th17 lymphocytes in patients with oral squamous cell carcinoma (OSCC). The neutrophil to lymphocyte ratio (NLR) biomarker value was determined. Besides, the influence of rhIL-17 on the proliferation level of the squamous cell carcinoma (SCC) malignant line cells was tested.

METHODS

Leukocytes were isolated in the density gradient and the CD16+ population was magnetically sorted. The percentages of neutrophil subpopulations, lymphocyte Th17, and IL-17 expression in the studied cells were determined on a flow cytometer. Squamous cell carcinoma proliferation was assessed with the MTT test.

RESULT

The existence of two populations of human neutrophils was determined: LDNs and NDNs. A higher percentage of LDNs and Th17 was observed with the concomitant lower percentage of NDNs in patients with OSCC as compared with the control group. NLR was elevated in patients with cancer. The highest IL-17 expression was obtained in the LDNs population in these patients. However, no influence of IL-17 on SCC proliferation could be determined.

CONCLUSION

The present study demonstrated a strong relationship between IL-17 concentration and the count of LDNs or Th17 in the course of OSCC, which may serve as a reference point for new therapies. Moreover, the obtained LDNs/NDNs and NLR values in patients with cancer prove their usefulness in diagnostic and prognostic in patients with OSCC.

Diagnostic, Therapeutic Predictive, and Prognostic Value of Neutrophil Extracellular Traps in Patients With Gastric Adenocarcinoma

Neutrophils are a significant population of infiltrated immune cells in the tumor microenvironment. Neutrophil extracellular traps (NETs) are implicated in the biological behavior of many malignant tumors. NETs can be degraded into soluble nucleosomes, leading to the release of fragments containing DNA and granule proteins into the peripheral blood (PB). Using human gastric cancer (GC) biopsies and PB samples, we investigated the specific value of NETs in GC from a clinical perspective. In summary, the formation of NETs was discovered in the tissue microenvironment and PB of GC patients. The amounts of NETs and neutrophil accumulation decreased from tumor tissue to paratumor tissue. In addition, the level of NETs in the PB gradually declined through the following patient populations: advanced disease patients, preoperative patients, postoperative patients, benign disease patients, and healthy controls. The levels of NETs in the plasma and serum were significantly correlated. As a serum biomarker, NETs had a better diagnostic value than carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA19-9) in GC. The neutrophil count and neutrophil to lymphocyte ratio (NLR) were significantly associated with the level of NETs in the PB. The existence of lymph node metastasis indicated a high level of NETs in the serum. Moreover, the level of NETs in the PB was inversely correlated with short-term efficacy in GC patients who had received advanced first-line treatment. The higher baseline level of NETs in the PB of patients with negative HER2 status was correlated with worse progression-free survival (PFS). And the level of NETs in the PB was a unfavorable independent prognostic factor for PFS in patients with advanced GC who had received first-line treatment. Thus, NETs have novel diagnostic, therapeutic predictive, and prognostic value in GC patients.

CD66b+ neutrophils and α-SMA+ fibroblasts predict clinical outcomes and benefits from postoperative chemotherapy in gastric adenocarcinoma

Background

Emerging evidence indicates that the tumor microenvironment (TME) influences tumor progression through the various cells it contains. Tumor‐associated neutrophils (TANs) and cancer‐associated fibroblasts (CAFs) are prominent constituents of diverse malignant solid tumors and are crucial in the TME and cancer evolution. However, the relationships and combined prognostic value of these two cell types are not known in gastric adenocarcinoma (GAC).

Materials and Methods

In total, 215 GAC patients who underwent curative surgery were enrolled. TANs were assessed by immunohistochemical staining for CD66b, and CAFs were evaluated by immunohistochemical staining for α‐smooth muscle actin (α‐SMA).

Results

The percentages of patients with high‐density TANs and CAFs in GAC tissue were 47.9% (103/215) and 43.3% (93/215), respectively. The densities of TANs and CAFs in GAC tissue samples were markedly elevated and independently correlated with GAC clinical outcomes. A strong correlation (R = .348, P < .001) was detected between TANs and CAFs in GAC. The combination of TANs and CAFs produced a more exact outcome than either factor alone. Patients with an α‐SMA^lowCD66b^high (hazard ratio [HR] = 1.791; 95% CI: 1.062‐3.021; P = .029), α‐SMA^highCD66b^low (HR = 2.402; 95% CI: 1.379‐4.183; P = .002), or α‐SMA^highCD66b^high (HR = 3.599; 95% CI: 2.330‐5.560; P < .001) phenotype were gradually correlated with poorer disease‐free survival than the subset of patients with an α‐SMA^lowCD66b^low phenotype. The same results were observed for disease‐specific survival in the subgroups. Noticeably, in stage II‐III patients with the α‐SMA^lowCD66b^low phenotype, an advantage was obtained with postoperative chemotherapeutics, and the risk of a poor prognosis was reduced compared with stage II‐III patients with the α‐SMA^lowCD66b^high, α‐SMA^highCD66b^low or α‐SMA^highCD66b^high phenotype (HR: 0.260, 95% CI: 0.124‐0.542, P < .001 for disease‐free survival; and HR: 0.258, 95% CI: 124‐0.538, P < .001 for disease‐specific survival).

Conclusion

Overall, we concluded that the combination of CD66b⁺ TANs and α‐SMA⁺ CAFs could be used as an independent factor for patient outcomes and to identify GAC patients who might benefit from the administration of postoperative chemotherapeutics.

Neutrophils in the Tumor Microenvironment

Neutrophils are the first responders to inflammation, infection, and injury. As one of the most abundant leukocytes in the immune system, neutrophils play an essential role in cancer progression, through multiple mechanisms, including promoting angiogenesis, immunosuppression, and cancer metastasis. Recent studies demonstrating elevated neutrophil to lymphocyte ratios suggest neutrophil as a potential therapeutic target and biomarker for disease status in cancer. This chapter will discuss the phenotypic and functional changes in the neutrophil in the tumor microenvironment, the underlying mechanism(s) of neutrophil facilitated cancer metastasis, and clinical potential of neutrophils as a prognostic/diagnostic marker and therapeutic target.

Tumor Associated Neutrophils. Their Role in Tumorigenesis, Metastasis, Prognosis and Therapy

Tumor Associated Neutrophils (TANs) are engaged into the tumor microenvironment by cytokines and chemokines, can be distinguished according to their activation and cytokine status and effects on tumor cell growing in N1 and N2 TANs. N1 TANs exert an antitumor activity, by direct or indirect cytotoxicity. N2 TANs stimulate immunosuppression, tumor growth, angiogenesis and metastasis by DNA instability, or by cytokines and chemokines release. In tumor patients, either a high number of TANs and Neutrophil-to-Lymphocyte Ratio (NLR) do correlate with poor prognosis, and, so far, TAN counts and NLR can be regarded as biomarkers. Owing to the pivotal role of TANs in stimulating tumor progression, therapeutic strategies to target TANs have been suggested, and two major approaches have been proposed: (a) targeting the CXCL-8/CXCR-1/CXCR-2 axis, thereby blocking TANs or (b) targeting substances produced by polymorpho-nuclear cells that promote tumor growth. Many studies have been accomplished either in vitro and in animal models, whereas clinical studies are restrained, presently, due to the risk of inducing immunosuppression. In this review, we deeply discuss the anti-tumorigenic or pro-tumorigenic activity of TANs. In particular, TANs relevance in tumor prognosis and in vitro therapeutic strategies are widely described. On-going clinical trials, aimed to inhibit neutrophil recruitment into the tumor are also accurately debated.

Glycolytic activation of peritumoral monocytes fosters immune privilege via the PFKFB3-PD-L1 axis in human hepatocellular carcinoma

BACKGROUND & AIMS

Programmed cell death 1 ligand 1 (PD-L1) expression on antigen-presenting cells is essential for T cell impairment, and PD-L1-expressing macrophages may mechanistically shape and therapeutically predict the clinical efficacy of PD-L1 or programmed cell death 1 blockade. We aimed to elucidate the mechanisms underlying PD-L1 upregulation in human tumor microenvironments, which remain poorly understood despite the clinical success of immune checkpoint inhibitors.

METHODS

Monocytes/macrophages were purified from peripheral blood, non-tumor, or paired tumor tissues of patients with hepatocellular carcinoma (HCC), and their possible glycolytic switch was evaluated. The underlying regulatory mechanisms and clinical significance of metabolic switching were studied with both ex vivo analyses and in vitro experiments.

RESULTS

We found that monocytes significantly enhanced the levels of glycolysis at the peritumoral region of human HCC. The activation of glycolysis induced PD-L1 expression on these cells and subsequently attenuated cytotoxic T lymphocyte responses in tumor tissues. Mechanistically, tumor-derived soluble factors, including hyaluronan fragments, induced the upregulation of a key glycolytic enzyme, PFKFB3, in tumor-associated monocytes. This enzyme not only modulated the cellular metabolic switch but also mediated the increased expression of PD-L1 by activating the nuclear factor kappa B signaling pathway in these cells. Consistently, the levels of PFKFB3⁺CD68⁺ cell infiltration in peritumoral tissues were negatively correlated with overall survival and could serve as an independent prognostic factor for survival in patients with HCC.

CONCLUSIONS

Our results reveal a mechanism by which the cellular metabolic switch regulates the pro-tumor functions of monocytes in a specific human tumor microenvironment. PFKFB3 in both cancer cells and tumor-associated monocytes is a potential therapeutic target in human HCC.

LAY SUMMARY

Programmed cell death 1 ligand 1 (PD-L1) expressed on antigen-presenting cells, rather than tumor cells, has been reported to play an essential role in checkpoint blockade therapy. A fundamental understanding of mechanisms that regulate the expression of PD-L1 on tumor-infiltrating monocytes/macrophages will undoubtedly lead to the possibility of developing novel PD-L1 blockade strategies with high specificity and efficiency. The current study unveils a novel mechanism by which metabolic switching links immune activation responses to immune tolerance in the tumor milieu, identifying potential targets for future immune-based anti-cancer therapies.

Neutrophils: Homing in on the myeloid mechanisms of metastasis

The metastasis cascade is complex and comprises several stages including local invasion into surrounding tissue, intravasation and survival of tumour cells in the circulation, and extravasation and colonisation of a distant site. It is increasingly clear that these processes are driven not only by signals within the tumour cells, but are also profoundly influenced by stromal cells and signals in the tumour microenvironment. Amongst the many cell types within the tumour microenvironment, immune cells such as lymphocytes, macrophages and neutrophils play a prominent role in tumour development and progression. Neutrophils, however, have only recently emerged as important players, particularly in metastasis. Here we review the current evidence suggesting a multi-faceted role for neutrophils in the metastatic cascade.

Pre-treatment neutrophil-lymphocyte ratio is associated with overall mortality in localized non-small cell lung cancer treated with stereotactic body radiotherapy

BACKGROUND

Neutrophil-lymphocyte ratio (NLR) has been associated with mortality in several disease sites. We hypothesized that NLR is associated with inferior outcomes in localized non-small cell lung cancer (NSCLC) treated with stereotactic body radiotherapy (SBRT).

METHODS

We evaluated the association of pre-treatment NLR, obtained within 6 months of starting SBRT, with overall survival, as well as primary tumor, regional, and distant recurrence. Multivariate Cox regression was then used to assess pre-treatment NLR as a predictor of mortality. We validated our findings in an independent cohort of patients treated at two other institutions. In a secondary analysis, we also evaluated the association of post-treatment NLR with mortality in the training cohort.

RESULTS

A total of 156 patients and 166 tumors were included in the training cohort with a median follow-up of 13.4 months. After dichotomization by median, NLR > 3.6 was associated with mortality on univariate (p = 0.010) and multivariate analysis (p = 0.023). In the validation cohort, NLR > 3.6 was similarly associated with mortality on univariate (p = 0.031) and multivariate (p = 0.007) analysis. In a secondary analysis in the training cohort, we found post-treatment NLR was significantly increased compared to pre-treatment NLR (p < 0.001) and associated with mortality on univariate analysis (p = 0.005) and multivariate analysis (p = 0.010).

CONCLUSIONS

Pre-treatment NLR > 3.6 is associated with mortality in patients treated with SBRT. This finding was validated in an independent cohort of patients treated at two other institutions. Additionally, post-treatment NLR was significantly increased from pre-treatment and associated with overall survival.

Preoperative Neutrophil-to-Lymphocyte Ratio Plus Platelet-to-Lymphocyte Ratio Predicts the Outcomes after Curative Resection for Hepatocellular Carcinoma

BACKGROUND

In recent years, inflammation-based scoring systems have been reported to predict survival in Hepatocellular Carcinoma (HCC). The aim of our study was to validate combined preoperative Neutrophil-to-Lymphocyte ratio (NLR)-Platelet-to-Lymphocyte ratio (PLR) in predicting overall survival (OS) and recurrence free survival (RFS) in patients who underwent curative resection for HCC.

METHODS

We conducted a retrospective study of HCC patients underwent liver resection with curative intent from January 2010 to December 2013. Receiver-operating characteristic (ROC) curve analysis was used to determine the optimal cut-off values for NLR and PLR. Patients with both NLR and PLR elevated were allocated a score of 2; patients showing one or neither of these indices elevated were accorded a score of 1 or 0, respectively.

RESULTS

132 patients with a median age of 66 years (range 18-87) underwent curative resection for HCC. Overall morbidity was 30.3%, 30-day mortality was 2.3%, and 90-day mortality was 6.8%. At a median follow-up of 24 months (range 1-88), 25% patients died, and 40.9% had recurrence. On multivariate analysis, elevated preoperative NLR-PLR was predictive of both OS (HR 2.496; CI 1.156-5.389; p=0.020) and RFS (HR 1.917; CI 1.161-3.166; p=0.011). The 5-year OS was 76% for NLR-PLR=0 group, 21.7% for the NLR-PLR=1 group, and 61.1% for the NLR-PLR=2 group, respectively. The 5-year RFS was 39.3% for the NLR-PLR=0 group, 18.4% for the NLR-PLR=1 group, and 21.1% for the NLR-PLR=2 group, respectively.

CONCLUSION

The preoperative NLR-PLR is predictive of both OS and RFS in patients with HCC undergoing curative liver resection.

Hyaluronan fragments produced during tissue injury: A signal amplifying the inflammatory response

Inflammation is a complex mechanism that plays a key role during diseases. Dynamic features of the extracellular matrix (ECM), in particular, during phases of tissue inflammation, have long been appreciated, and a great deal of several investigations has focused on the effects of ECM derivatives on cell function. It has been well defined that during inflammatory and tissue injury, ECM components were degraded. ECM degradation direct consequence is the loss of cell homeostasis, while a further consequence is the generation of fragments from larger precursor molecules. These bio-functional ECM shred defined matrikines as capable of playing different actions, especially when they function as powerful initiators, able to prime the inflammatory mechanism. Non-sulphated glycosaminoglycan hyaluronan (HA) is the major component of the ECM that undergoes specific modulation during tissue damage and inflammation. HA fragments at very low molecular weight are produced as a result of HA depolymerization. Several evidence has considered the plausibility that HA breakdown products play a modulatory action in the sequential stages of inflammation, although the effective mechanism of these HA derivative compounds act is not completely defined. This review will focus on the pro-inflammatory effects of HA fragments in recent years obtained by in vitro investigations.