IL-1R8 is a checkpoint in NK cells regulating anti-tumour and anti-viral activity

Bioinformatics analysis and validation of genes related to paclitaxel's anti-breast cancer effect through immunogenic cell death

Research indicated that Paclitaxel (PTX) can induce immunogenic cell death (ICD) through immunogenic modulation. However, the combination of PTX and ICD has not been extensively studied in breast cancer (BRCA). The TCGA-BRCA and GSE20685 datasets were enrolled in this study. Samples from the TCGA-BRCA dataset were consistently clustered based on selected immunogenic cell death-related genes (ICD-RGs). Next, candidate genes were obtained by overlapping differentially expressed genes (DEGs) between BRCA and normal groups, intersecting genes common to DEGs between cluster1 and cluster2 and hub module genes, and target genes of PTX from five databases. The univariate Cox algorithm and the least absolute shrinkage and selection operator (LASSO) were performed to obtain biomarkers and build a risk model. Following observing the immune microenvironment in differential risk subgroups, single-gene gene set enrichment analysis (GSEA) was carried out in all biomarkers. Finally, the expression of biomarkers was analyzed. Enrichment analysis showed that 626 intersecting genes were linked with inflammatory response. Further five biomarkers (CHI3L1, IL18, PAPLN, SH2D2A, and UBE2L6) were identified and a risk model was built. The model's performance was validated using GSE20685 dataset. Furthermore, the biomarkers were enriched with adaptive immune response. Lastly, the experimental results indicated that the alterations in IL18, SH2D2A, and CHI3L1 expression after treatment matched those in the public database. In this study, Five PTX-ICD-related biomarkers (CHI3L1, IL18, PAPLN, SH2D2A, and UBE2L6) were identified to aid in predicting BRCA treatment outcomes.

Neutrophils Mediate Protection Against Colitis and Carcinogenesis by Controlling Bacterial Invasion and IL22 Production by γδ T Cells

Neutrophils are the most abundant leukocytes in human blood and play a primary role in resistance against invading microorganisms and in the acute inflammatory response. However, their role in colitis and colitis-associated colorectal cancer is still under debate. This study aims to dissect the role of neutrophils in these pathologic contexts by using a rigorous genetic approach. Neutrophil-deficient mice (Csf3r-/- mice) were used in classic models of colitis and colitis-associated colorectal cancer and the role of neutrophils was assessed by histologic, cellular, and molecular analyses coupled with adoptive cell transfer. We also performed correlative analyses using human datasets. Csf3r-/- mice showed increased susceptibility to colitis and colitis-associated colorectal cancer compared with control Csf3r+/+ mice and adoptive transfer of neutrophils in Csf3r-/- mice reverted the phenotype. In colitis, Csf3r-/- mice showed increased bacterial invasion and a reduced number of healing ulcers in the colon, indicating a compromised regenerative capacity of epithelial cells. Neutrophils were essential for γδ T-cell polarization and IL22 production. In patients with ulcerative colitis, expression of CSF3R was positively correlated with IL22 and IL23 expression. Moreover, gene signatures associated with epithelial-cell development, proliferation, and antimicrobial response were enriched in CSF3Rhigh patients. Our data support a model where neutrophils mediate protection against intestinal inflammation and colitis-associated colorectal cancer by controlling the intestinal microbiota and driving the activation of an IL22-dependent tissue repair pathway.

IL-37 dampens immunosuppressive functions of MDSCs via metabolic reprogramming in the tumor microenvironment

Interleukin-37 (IL-37) has been shown to inhibit tumor growth in various cancer types. However, the immune regulatory function of IL-37 in the tumor microenvironment is unclear. Here, we established a human leukocyte antigen-I (HLA-I)-matched humanized patient-derived xenograft hepatocellular carcinoma (HCC) model and three murine orthotopic HCC models to study the function of IL-37 in the tumor microenvironment. We found that IL-37 inhibited HCC growth and promoted T cell activation. Further study revealed that IL-37 impaired the immunosuppressive capacity of myeloid-derived suppressor cells (MDSCs). Pretreatment of MDSCs with IL-37 before adoptive transfer attenuated their tumor-promoting function in HCC tumor-bearing mice. Moreover, IL-37 promoted both glycolysis and oxidative phosphorylation in MDSCs, resulting in the upregulation of ATP release, which impaired the immunosuppressive capacity of MDSCs. Collectively, we demonstrated that IL-37 inhibited tumor development through dampening MDSCs' immunosuppressive capacity in the tumor microenvironment via metabolic reprogramming, making it a promising target for future cancer immunotherapy.

Bioengineering strategies to enhance the interleukin-18 bioactivity in the modern toolbox of cancer immunotherapy

Cytokines are the first modern immunotherapeutic agents used for activation immunotherapy. Interleukin-18 (IL-18) has emerged as a potent anticancer immunostimulatory cytokine over the past three decades. IL-18, structurally is a stable protein with very low toxicity at biological doses. IL-18 promotes the process of antigen presentation and also enhances innate and acquired immune responses. It can induce the production of proinflammatory cytokines and increase tumor infiltration of effector immune cells to revert the immunosuppressive milieu of tumors. Furthermore, IL-18 can reduce tumorigenesis, suppress tumor angiogenesis, and induce tumor cell apoptosis. These characteristics present IL-18 as a promising option for cancer immunotherapy. Although several preclinical studies have reported the immunotherapeutic potential of IL-18, clinical trials using it as a monotherapy agent have reported disappointing results. These results may be due to some biological characteristics of IL-18. Several bioengineering approaches have been successfully used to correct its defects as a bioadjuvant. Currently, the challenge with this anticancer immunotherapeutic agent is mainly how to use its capabilities in a rational combinatorial therapy for clinical applications. The present study discussed the strengths and weaknesses of IL-18 as an immunotherapeutic agent, followed by comprehensive review of various promising bioengineering approaches that have been used to overcome its disadvantages. Finally, this study highlights the promising application of IL-18 in modern combinatorial therapies, such as chemotherapy, immune checkpoint blockade therapy, cell-based immunotherapy and cancer vaccines to guide future studies, circumventing the barriers to administration of IL-18 for clinical applications, and bring it to fruition as a potent immunotherapy agent in cancer treatment.

IL-1 Family Members in Bone Sarcomas

IL-1 family members have multiple pleiotropic functions affecting various tissues and cells, including the regulation of the immune response, hematopoietic homeostasis, bone remodeling, neuronal physiology, and synaptic plasticity. Many of these activities are involved in various pathological processes and immunological disorders, including tumor initiation and progression. Indeed, IL-1 family members have been described to contribute to shaping the tumor microenvironment (TME), determining immune evasion and drug resistance, and to sustain tumor aggressiveness and metastasis. This review addresses the role of IL-1 family members in bone sarcomas, particularly the highly metastatic osteosarcoma (OS) and Ewing sarcoma (EWS), and discusses the IL-1-family-related mechanisms that play a role in bone metastasis development. We also consider the therapeutic implications of targeting IL-1 family members, which have been proposed as (i) relevant targets for anti-tumor and anti-metastatic drugs; (ii) immune checkpoints for immune suppression; and (iii) potential antigens for immunotherapy.

Inhibitory receptors and checkpoints on NK cells: Implications for cancer immunotherapy

With the success of immunosuppressive checkpoint in tumor therapy, the corresponding adverse response and drug resistance defects have been exposed. T cells and NK cells are the body's immune system of the two substantial main forces. in recent years, study of T cell checkpoints appeared a certain block, such as PD-1 the effect not benign, on the distribution of NK cell surface excitatory and inhibitory receptors under normal conditions to maintain steady, could be targeted in the tumor treatment blockade have therapeutic effect. This paper reviews the function of NK cells and the effects of corresponding receptors in various types of tumors, providing a direction for the selection of appropriate gate control sites for future treatment.

Interplay between inflammasomes and PD-1/PD-L1 and their implications in cancer immunotherapy

The inflammasomes play crucial roles in inflammation and cancer development, while the PD-1/PD-L1 pathway is critical for immune suppression in the tumor microenvironment (TME). Recent research indicates a reciprocal regulatory relationship between inflammasomes and PD-1/PD-L1 signaling in cancer development and PD-1 blockade treatment. By activating in diverse cells in tumor tissues, inflammasome upregulates PD-L1 level in the TME. Moreover, the regulation of PD-1/PD-L1 activity by inflammasome activation involves natural killer cells, tumor-associated macrophages and myeloid-derived suppressor cells. Conversely, PD-1 blockade can activate the inflammasome, potentially influencing treatment outcomes. The interplay between inflammasomes and PD-1/PD-L1 has profound and intricate effects on cancer development and treatment. In this review, we discuss the crosstalk between inflammasomes and PD-1/PD-L1 in cancers, exploring their implications for tumorigenesis, metastasis and immune checkpoint inhibitor (ICI) resistance. The combined therapeutic strategies targeting both inflammasomes and checkpoint molecules hold promising potential as treatments for cancer.

The anti-inflammatory cytokine IL-37 improves the NK cell-mediated anti-tumor response

IL-37 is a member of the IL-1 superfamily exerting anti-inflammatory functions in a number of diseases. Extracellular IL-37 triggers the inhibitory receptor IL-1R8 that is known to regulate different NK cell pathways and functional activities including their anti-tumor effect. However, the effect of IL-37 on human NK cell functions is still to be unveiled. This study aimed to investigate the functional effect of IL-37 in human NK cells activated with IL-15. We found that IL-37 enhanced both NK cell cytotoxic activity against different tumor cell lines and cytokines production. These effects were associated with increased phosphorylation of ERK and NF-Kb. The improved NK cell activity was also strictly related to a time-dependent GSK3β-mediated degradation of IL-1R8. The enhanced activation profile of IL-37 treated NK cells possibly due to IL-1R8 degradation was confirmed by the results with IL-1R8-silenced NK cells. Lastly, in line with these data, through the analysis of the TNM plot database of a large group of patients, IL-37 mRNA expression was found to be significantly lower in colon and skin cancers than in normal tissues. Colon adenocarcinoma and neuroblastoma patients with higher IL-37 mRNA levels had significantly higher overall survival, suggesting that the presence of IL-37 might be considered an independent positive prognostic factor for this tumor. Our results provide novel information on the mechanisms regulating IL-1R8 function in human NK cells, highlighting the IL-37-IL-1R8 axis as a potential new target to improve the anti-tumor immune response.

Microenvironmental signals shaping NK-cell reactivity in cancer

Since the postulation of the "missing-self" concept, much progress has been made in defining requirements for NK-cell activation. Unlike T lymphocytes that process signals from receptors in a hierarchic manner dominated by the T-cell receptors, NK cells integrate receptor signals more "democratically." Signals originate not only the downstream of cell-surface receptors triggered by membrane-bound ligands or cytokines, but are also mediated by specialized microenvironmental sensors that perceive the cellular surrounding by detecting metabolites or the availability of oxygen. Thus, NK-cell effector functions are driven in an organ and disease-dependent manner. Here, we review the latest findings on how NK-cell reactivity in cancer is determined by the reception and integration of complex signals. Finally, we discuss how this knowledge can be exploited to guide novel combinatorial approaches for NK-cell-based anticancer therapies.

NK cell exhaustion in the tumor microenvironment

Natural killer (NK) cells kill mutant cells through death receptors and cytotoxic granules, playing an essential role in controlling cancer progression. However, in the tumor microenvironment (TME), NK cells frequently exhibit an exhausted status, which impairs their immunosurveillance function and contributes to tumor immune evasion. Emerging studies are ongoing to reveal the properties and mechanisms of NK cell exhaustion in the TME. In this review, we will briefly introduce the maturation, localization, homeostasis, and cytotoxicity of NK cells. We will then summarize the current understanding of the main mechanisms underlying NK cell exhaustion in the TME in four aspects: dysregulation of inhibitory and activating signaling, tumor cell-derived factors, immunosuppressive cells, and metabolism and exhaustion. We will also discuss the therapeutic approaches currently being developed to reverse NK cell exhaustion and enhance NK cell cytotoxicity in the TME.

Interleukin-1 family cytokines in liver cell death: a new therapeutic target for liver diseases

INTRODUCTION

Liver cell death represents a basic biological process regulating the progression of liver diseases via distinct mechanisms. Accumulating evidence has uncovered participation of interleukin (IL)-1 family cytokines in liver cell death. Upon activation of cell death induced by hepatotoxic stimuli, IL1 family cytokines released by hepatic dead cells stimulate recruitment of immune cells, which in turn influence inflammation and subsequent liver injury, thus highlighting their potential as therapeutic targets in liver diseases. Enhancing our comprehension of mechanisms underlying IL1 family cytokine signaling in cell death responses could pave the way for novel therapeutic interventions aimed at addressing liver cell death-related liver pathologies.

AREAS COVERED

This review summarizes the recent findings reported in preclinical and clinical studies on mechanisms of liver cell death, alongside participation of IL1 family members consisting of IL1α, ILβ, IL18, and IL33 in liver cell death and their significant implications in liver diseases.

EXPERT OPINION

Discovery of new and innovative therapeutic approaches for liver diseases will need close cooperation between fundamental and clinical scientists to better understand the multi-step processes behind IL1 family cytokines' contributions to liver cell death.

NK Cells in Cancer: Mechanisms of Dysfunction and Therapeutic Potential

Natural killer cells (NK) are innate lymphocytes endowed with the ability to recognize and kill cancer cells. Consequently, adoptive transfer of autologous or allogeneic NK cells represents a novel opportunity in cancer treatment that is currently under clinical investigation. However, cancer renders NK cells dysfunctional, thus restraining the efficacy of cell therapies. Importantly, extensive effort has been employed to investigate the mechanisms that restrain NK cell anti-tumor function, and the results have offered forthcoming solutions to improve the efficiency of NK cell-based therapies. The present review will introduce the origin and features of NK cells, summarize the mechanisms of action and causes of dysfunction of NK cells in cancer, and frame NK cells in the tumoral microenvironment and in the context of immunotherapies. Finally, we will discuss therapeutic potential and current limitations of NK cell adoptive transfer in tumors.

Modulation of T-cell function by myeloid-derived suppressor cells in hematological malignancies

Myeloid-derived suppressor cells (MDSCs) are pathologically activated neutrophils and monocytes that negatively regulate the immune response to cancer and chronic infections. Abnormal myelopoiesis and pathological activation of myeloid cells generate this heterogeneous population of myeloid-derived suppressor cells. They are characterized by their distinct transcription, phenotypic, biochemical, and functional features. In the tumor microenvironment (TME), myeloid-derived suppressor cells represent an important class of immunosuppressive cells that correlate with tumor burden, stage, and a poor prognosis. Myeloid-derived suppressor cells exert a strong immunosuppressive effect on T-cells (and a broad range of other immune cells), by blocking lymphocyte homing, increasing production of reactive oxygen and nitrogen species, promoting secretion of various cytokines, chemokines, and immune regulatory molecules, stimulation of other immunosuppressive cells, depletion of various metabolites, and upregulation of immune checkpoint molecules. Additionally, the heterogeneity of myeloid-derived suppressor cells in cancer makes their identification challenging. Overall, they serve as a major obstacle for many cancer immunotherapies and targeting them could be a favorable strategy to improve the effectiveness of immunotherapeutic interventions. However, in hematological malignancies, particularly B-cell malignancies, the clinical outcomes of targeting these myeloid-derived suppressor cells is a field that is still to be explored. This review summarizes the complex biology of myeloid-derived suppressor cells with an emphasis on the immunosuppressive pathways used by myeloid-derived suppressor cells to modulate T-cell function in hematological malignancies. In addition, we describe the challenges, therapeutic strategies, and clinical relevance of targeting myeloid-derived suppressor cells in these diseases.

Interleukin-37 promotes DMBA/TPA skin cancer through SIGIRR-mediated inhibition of glycolysis in CD103+DC cells

Interleukin 37 (IL-37), a member of the IL-1 family, is considered a suppressor of innate and adaptive immunity and, hence is a regulator of tumor immunity. However, the specific molecular mechanism and role of IL-37 in skin cancer remain unclear. Here, we report that IL-37b-transgenic mice (IL-37tg) treated with the carcinogenic 7,12-dimethylbenzoanthracene (DMBA)/12-o-tetradecylphorbol-13-acetate (TPA) exhibited enhanced skin cancer and increased tumor burden in the skin by inhibiting the function of CD103⁺ dendritic cells (DCs). Notably, IL-37 induced rapid phosphorylation of adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK), and via single immunoglobulin IL-1-related receptor (SIGIRR), inhibited the long-term Akt activation. Specifically, by affecting the SIGIRR-AMPK-Akt signaling axis, which is related to the regulation of glycolysis in CD103⁺DCs, IL-37 inhibited their anti-tumor function. Our results show that a marked correlation between the CD103⁺DC signature (IRF8, FMS-like tyrosine kinase 3 ligand, CLEC9A, CLNK, XCR1, BATF3, and ZBTB46) and chemokines C-X-C motif chemokine ligand 9, CXCL10, and CD8A in a mouse model with DMBA/TPA-induced skin cancer. In a word, our results highlight that IL-37 as an inhibitor of tumor immune surveillance through modulating CD103⁺DCs and establishing an important link between metabolism and immunity as a therapeutic target for skin cancer.

IL-1R8: A molecular brake of anti-tumor and anti-viral activity of NK cells and ILC

Interleukin-1 receptor family members (ILRs) and Toll-Like Receptors (TLRs) play pivotal role in immunity and inflammation and are expressed by most cell types including cells of both the innate and adaptive immune system. In this context, IL-1 superfamily members are also important players in regulating function and differentiation of adaptive and innate lymphoid cells. This system is tightly regulated in order to avoid uncontrolled activation, which may lead to detrimental inflammation contributing to autoimmune or allergic responses. IL-1R8 (also known as TIR8 or SIGIRR) is a member of the IL-1R family that acts as a negative regulator dampening ILR and TLR signaling and as a co-receptor for human IL-37. Human and mouse NK cells, that are key players in immune surveillance of tumors and infections, express high level of IL-1R8. In this review, we will summarize our current understanding on the structure, expression and function of IL-1R8 and we will also discuss the emerging role of IL-1R8 as an important checkpoint regulating NK cells function in pathological conditions including cancer and viral infections.

Locally sourced: site-specific immune barriers to metastasis

Tumour cells migrate very early from primary sites to distant sites, and yet metastases often take years to manifest themselves clinically or never even surface within a patient's lifetime. This pause in cancer progression emphasizes the existence of barriers that constrain the growth of disseminated tumour cells (DTCs) at distant sites. Although the nature of these barriers to metastasis might include DTC-intrinsic traits, recent studies have established that the local microenvironment also controls the formation of metastases. In this Perspective, I discuss how site-specific differences of the immune system might be a major selective growth restraint on DTCs, and argue that harnessing tissue immunity will be essential for the next stage in immunotherapy development that reliably prevents the establishment of metastases.

Tissue resident iNKT17 cells facilitate cancer cell extravasation in liver metastasis via interleukin-22

During metastasis, cancer cells invade, intravasate, enter the circulation, extravasate, and colonize target organs. Here, we examined the role of interleukin (IL)-22 in metastasis. Immune cell-derived IL-22 acts on epithelial tissues, promoting regeneration and healing upon tissue damage, but it is also associated with malignancy. Il22-deficient mice and mice treated with an IL-22 antibody were protected from colon-cancer-derived liver and lung metastasis formation, while overexpression of IL-22 promoted metastasis. Mechanistically, IL-22 acted on endothelial cells, promoting endothelial permeability and cancer cell transmigration via induction of endothelial aminopeptidase N. Multi-parameter flow cytometry and single-cell sequencing of immune cells isolated during cancer cell extravasation into the liver revealed iNKT17 cells as source of IL-22. iNKT-cell-deficient mice exhibited reduced metastases, which was reversed by injection of wild type, but not Il22-deficient, invariant natural killer T (iNKT) cells. IL-22-producing iNKT cells promoting metastasis were tissue resident, as demonstrated by parabiosis. Thus, IL-22 may present a therapeutic target for prevention of metastasis.

A TMEM16J variant leads to dysregulated cytosolic calcium which may lead to renal disease

SIGIRR (single immunoglobulin IL-1 related receptor), PKP3 (plakophilin 3), and TMEM16J (anoctamin 9), a putative calcium-activated ion channel and phospholipid scramblase, control the immune response and the extent of inflammation. Variants of SIGIRR/PKP3/TMEM16J lead to severe inflammatory diseases such as pneumonia, enterocolitis, and kidney graft rejection. Meta-analysis of genome-wide association studies identified TMEM16J-T604A as a promotor for chronic kidney disease (CKD), but the disease mechanism and function of TMEM16J remain unknown. Here, we demonstrate TMEM16J as a calcium-activated calcium-permeable channel, which is expressed in the endoplasmic reticulum (ER). TMEM16J controls the intracellular distribution of calcium, and inhibits intracellular receptor-mediated Ca²⁺ signals and Ca²⁺ -dependent activation of ion channels, but augments transcription and release of pro-inflammatory cytokines. Renal epithelial cells expressing the variant TMEM16J-T604A show enhanced calcium signals when compared to cells expressing wt-TMEM16J, and demonstrate spontaneous transcription and release of cytokines. This study identifies TMEM16J as an important regulator of intracellular Ca²⁺ signals, ion channel activity, and cytokine release. TMEM16J may therefore affect immune response in renal tissue and immune cells.

Size-advantage of monovalent nanobodies against the macrophage mannose receptor for deep tumor penetration and tumor-associated macrophage targeting

Rationale: Nanobodies (Nbs) have emerged as an elegant alternative to the use of conventional monoclonal antibodies in cancer therapy, but a detailed microscopic insight into the in vivo pharmacokinetics of different Nb formats in tumor-bearers is lacking. This is especially relevant for the recognition and targeting of pro-tumoral tumor-associated macrophages (TAMs), which may be located in less penetrable tumor regions. Methods: We employed anti-Macrophage Mannose Receptor (MMR) Nbs, in a monovalent (m) or bivalent (biv) format, to assess in vivo TAM targeting. Intravital and confocal microscopy were used to analyse the blood clearance rate and targeting kinetics of anti-MMR Nbs in tumor tissue, healthy muscle tissue and liver. Fluorescence Molecular Tomography was applied to confirm anti-MMR Nb accumulation in the primary tumor and in metastatic lesions. Results: Intravital microscopy demonstrated significant differences in the blood clearance rate and macrophage targeting kinetics of (m) and (biv)anti-MMR Nbs, both in tumoral and extra-tumoral tissue. Importantly, (m)anti-MMR Nbs are superior in reaching tissue macrophages, an advantage that is especially prominent in tumor tissue. The administration of a molar excess of unlabelled (biv)anti-MMR Nbs increased the (m)anti-MMR Nb bioavailability and impacted on its macrophage targeting kinetics, preventing their accumulation in extra-tumoral tissue (especially in the liver) but only partially influencing their interaction with TAMs. Finally, anti-MMR Nb administration not only allowed the visualization of TAMs in primary tumors, but also at a distant metastatic site. Conclusions: These data describe, for the first time, a microscopic analysis of (m) and (biv)anti-MMR Nb pharmacokinetics in tumor and healthy tissues. The concepts proposed in this study provide important knowledge for the future use of Nbs as diagnostic and therapeutic agents, especially for the targeting of tumor-infiltrating immune cells.

The Tumor Microenvironment of Hepatocellular Carcinoma: Untying an Intricate Immunological Network

HCC, the most prevalent form of primary liver cancer, is prototypically an inflammation-driven cancer developing after years of inflammatory insults. Consequently, the hepatic microenvironment is a site of complex immunological activities. Moreover, the tolerogenic nature of the liver can act as a barrier to anti-tumor immunity, fostering cancer progression and resistance to immunotherapies based on immune checkpoint inhibitors (ICB). In addition to being a site of primary carcinogenesis, many cancer types have high tropism for the liver, and patients diagnosed with liver metastasis have a dismal prognosis. Therefore, understanding the immunological networks characterizing the tumor microenvironment (TME) of HCC will deepen our understanding of liver immunity, and it will underpin the dominant mechanisms controlling both spontaneous and therapy-induced anti-tumor immune responses. Herein, we discuss the contributions of the cellular and molecular components of the liver immune contexture during HCC onset and progression by underscoring how the balance between antagonistic immune responses can recast the properties of the TME and the response to ICB.

Inflammatory-driven NK cell maturation and its impact on pathology

NK cells are innate lymphocytes involved in a large variety of contexts and are crucial in the immunity to intracellular pathogens as well as cancer due to their ability to kill infected or malignant cells. Thus, they harbor a strong potential for clinical and therapeutic use. NK cells do not require antigen exposure to get activated; their functional response is rather based on a balance between inhibitory/activating signals and on the diversity of germline-encoded receptors they express. In order to reach optimal functional status, NK cells go through a step-wise development in the bone marrow before their egress, and dissemination into peripheral organs via the circulation. In this review, we summarize bone marrow NK cell developmental stages and list key factors involved in their differentiation before presenting newly discovered and emerging factors that regulate NK cell central and peripheral maturation. Lastly, we focus on the impact inflammatory contexts themselves can have on NK cell development and functional maturation.

SIGIRR deficiency contributes to CD4 T cell abnormalities by facilitating the IL1/C/EBPβ/TNF-α signaling axis in rheumatoid arthritis

Background

Rheumatoid arthritis (RA) is a complex autoimmune disease with multiple etiological factors, among which aberrant memory CD4 T cells activation plays a key role in the initiation and perpetuation of the disease. SIGIRR (single immunoglobulin IL-1R-related receptor), a member of the IL-1 receptor (ILR) family, acts as a negative regulator of ILR and Toll-like receptor (TLR) downstream signaling pathways and inflammation. The aim of this study was to investigate the potential roles of SIGIRR on memory CD4 T cells in RA and the underlying cellular and molecular mechanisms.

Methods

Single-cell transcriptomics and bulk RNA sequencing data were integrated to predict SIGIRR gene distribution on different immune cell types of human PBMCs. Flow cytometry was employed to determine the differential expression of SIGIRR on memory CD4 T cells between the healthy and RA cohorts. A Spearman correlation study was used to determine the relationship between the percentage of SIGIRR+ memory CD4 T cells and RA disease activity. An AIA mouse model (antigen-induced arthritis) and CD4 T cells transfer experiments were performed to investigate the effect of SIGIRR deficiency on the development of arthritis in vivo. Overexpression of SIGIRR in memory CD4 T cells derived from human PBMCs or mouse spleens was utilized to confirm the roles of SIGIRR in the intracellular cytokine production of memory CD4 T cells. Immunoblots and RNA interference were employed to understand the molecular mechanism by which SIGIRR regulates TNF-α production in CD4 T cells.

Results

SIGIRR was preferentially distributed by human memory CD4 T cells, as revealed by single-cell RNA sequencing. SIGIRR expression was substantially reduced in RA patient-derived memory CD4 T cells, which was inversely associated with RA disease activity and related to enhanced TNF-α production. SIGIRR-deficient mice were more susceptible to antigen-induced arthritis (AIA), which was attributed to unleashed TNF-α production in memory CD4 T cells, confirmed by decreased TNF-α production resulting from ectopic expression of SIGIRR. Mechanistically, SIGIRR regulates the IL-1/C/EBPβ/TNF-α signaling axis, as established by experimental evidence and cis-acting factor bioinformatics analysis.

Conclusion

Taken together, SIGIRR deficiency in memory CD4 T cells in RA raises the possibility that receptor induction can target key abnormalities in T cells and represents a potentially novel strategy for immunomodulatory therapy.

IL-37 alleviates Coxsackievirus B3-induced viral myocarditis via inhibiting NLRP3 inflammasome-mediated pyroptosis

Our study aims to verify the potential effects and underlying mechanisms of IL-37 in Coxsackievirus B3 (CVB3)-induced viral myocarditis (VMC). VMC model was established by intraperitoneal injection of CVB3 into 6-week-old male balb-c mice on day 0. Each mouse of the IL-37-control group and IL-37-VMC CVB3 groups was intraperitoneally injected with IL-37 on day 4 and day 7. The cardiac function was evaluated by transthoracic echocardiography including LVEF, LVFE, IVSs and IVSd. Myocardial injury was measured by Elisa for serum cTnI. The inflammation infiltration and fibrosis were evaluated by hematoxylin and eosin (HE) staining and Masson staining. The expression levels of NLRP3 inflammasome components in pyroptosis were determined by western blot, Elisa, and immunofluorescent analysis. We also detected the expression of IL-37-IL-1R8 in PBMCs by immunofluorescence after injection with CVB3 and IL-37. Compared with the VMC group, mice received CVB3 and IL-37 have improved cardiac function, reduced inflammation infiltration and fibrosis, and with lower expression of cTnI, IL-1β, IL-18 and NLRP3 inflammasome component. IL-37 weakened the upregulation of GSDMD and phosphorylation of NF-κB p65 induced by CVB3. Exogenous addition of IL-37 with CVB3 further increases the production of IL-37-IL-1R8 -IL-18RA complex in vitro. Our findings indicate that IL-37 alleviates CVB3-induced VMC, which may be produced by inhibiting NLRP3 inflammasome-mediated pyroptosis, NF-κB signaling pathway, and IL-37-IL-1R8 -IL-18RA complex.

Cellular Immunotherapy for Medulloblastoma

Medulloblastoma (MB) is the most common malignant brain tumor in children, making up ~20% of all primary pediatric brain tumors. Current therapies consist of maximal surgical resection and aggressive radio- and chemotherapy. A third of the treated patients cannot be cured and survivors are often left with devastating long-term side effects. Novel efficient and targeted treatment is desperately needed for this patient population. Cellular immunotherapy aims to enhance and utilize immune cells to target tumors, and has been proven successful in various cancers. However, for MB, the knowledge and possibilities of cellular immunotherapy are limited. In this review, we provide a comprehensive overview of the current status of cellular immunotherapy for MB, from fundamental in vitro research to in vivo models and (ongoing) clinical trials. In addition, we compare our findings to cellular immunotherapy in glioma, an MB-like intracranial tumor. Finally, future possibilities for MB are discussed to improve efficacy and safety.

Mitochondrial fragmentation in liver cancer: Emerging player and promising therapeutic opportunities

Hepatocellular carcinoma (HCC) is the leading cause of cancer-related death worldwide. Enhanced mitochondrial fragmentation (MF) is associated with poor prognosis in HCC patients. However, its molecular mechanism in HCC remains elusive. Although enhanced MF activates effector T cells and dendritic cells, it induces immunoescape by decreasing the number and cytotoxicity of natural killer cells in the HCC immune microenvironment. Therefore, the influence of MF on the activity of different immune cells is a great challenge. Enhanced MF contributes to maintaining stemness by promoting the asymmetric division of liver cancer stem cells (LCSCs), suggesting that MF may become a potential target for HCC recurrence, metastasis, and chemotherapy resistance. Moreover, mechanistic studies suggest that MF may promote tumour progression through autophagy, oxidative stress, and metabolic reprogramming. Human-induced hepatocyte organoids are a recently developed system that can be genetically manipulated to mimic cancer initiation and identify potential preventive treatments. We can use it to screen MF-related candidate inhibitors of HCC progression and further explore the role of MF in hepatocarcinogenesis. We herein describe the mechanisms by which MF contributes to HCC development, discuss potential therapeutic approaches, and highlight the possibility that MF modulation has a synergistic effect with immunotherapy.

NK cell immunometabolism as target for liver cancer therapy

Natural killer (NK) cells are being used effectively as a potential candidate in tumor immunotherapy. However, the migration and transport of NK cells to solid tumors is inadequate. NK cell dysfunction, tumor invasiveness, and metastasis are associated with altered metabolism of NK cells in the liver cancer microenvironment. However, in liver cancers, metabolic impairment of NK cells is still not understood fully. Evidence from various sources has shown that the interaction of NK cell's immune checkpoints with its metabolic checkpoints is responsible for the regulation of the development and function of these cells. How immune checkpoints contribute to metabolic programming is still not fully understood, and how this can be beneficial needs a better understanding, but they are emerging to be incredibly compelling to rebuilding the function of NK cells in the tumor. It is expected to represent a potential aim that focuses on improving the efficacy of therapies based on NK cells for treating liver cancer. Here, the recent advancements made to understand the NK cell's metabolic reprogramming in liver cancer have been summarized, along with the possible interplay between the immune and the metabolic checkpoints in NK cell function. Finally, an overview of some potential metabolic-related targets that can be used for liver cancer therapy treatment has been presented.

Molecular characterization and functional analysis of DIGIRR from golden pompano (Trachinotus ovatus)

Mammalian single immunoglobulin (Ig) interleukin-1 receptor related molecule (SIGIRR), an important member of the Toll/interleukin-1 receptor (TIR) family, plays important balancing roles in the inflammatory responses. In the present study, the double Ig interleukin-1 receptor related molecule (DIGIRR), the homologous of SIGIRR, was characterized in golden pompano (Trachinotus ovatus) (termed as trDIGIRR). The full-length cDNA of trDIGIRR was 2,167 bp with an open reading frame (ORF) of 1,572 bp encoding 523 amino acids. The trDIGIRR contained several conserved domains including a signal peptide, two Ig domains, a transmembrane domain and a TIR domain, and shared high sequence identities with its teleost counterparts. Realtime qPCR analysis revealed that the trDIGIRR was distributed in all tissues examined, with high expressions in intestine, liver and head kidney. The expressions of trDIGIRR were induced by Vibrio alginolyticus, lipopolysaccharide (LPS) and polyinosinic-polycytidylic acid (poly I:C) challenge. Further analysis revealed that trDIGIRR was mainly located in the cytoplasm. In addition, the co-immunoprecipitation (co-IP) assay identified that trDIGIRR could interact with myeloid differentiation factor 88 (MyD88), but not interact with TIR domain containing adaptor protein inducing interferon-β (TRIF). Our results provide basis for studying the immune role of fish DIGIRR.

Macrophages as tools and targets in cancer therapy

Tumour-associated macrophages are an essential component of the tumour microenvironment and have a role in the orchestration of angiogenesis, extracellular matrix remodelling, cancer cell proliferation, metastasis and immunosuppression, as well as in resistance to chemotherapeutic agents and checkpoint blockade immunotherapy. Conversely, when appropriately activated, macrophages can mediate phagocytosis of cancer cells and cytotoxic tumour killing, and engage in effective bidirectional interactions with components of the innate and adaptive immune system. Therefore, they have emerged as therapeutic targets in cancer therapy. Macrophage-targeting strategies include inhibitors of cytokines and chemokines involved in the recruitment and polarization of tumour-promoting myeloid cells as well as activators of their antitumorigenic and immunostimulating functions. Early clinical trials suggest that targeting negative regulators (checkpoints) of myeloid cell function indeed has antitumor potential. Finally, given the continuous recruitment of myelomonocytic cells into tumour tissues, macrophages are candidates for cell therapy with the development of chimeric antigen receptor effector cells. Macrophage-centred therapeutic strategies have the potential to complement, and synergize with, currently available tools in the oncology armamentarium.

Macrophages can promote tumorigenesis and enhance the antitumour response. This Review discusses the molecular mechanisms underlying the reprogramming of macrophages in the tumour microenvironment and provides an overview of macrophage-targeted therapies for the treatment of cancer.

The unique role of innate lymphoid cells in cancer and the hepatic microenvironment

Cancer is a complex disease, and despite incredible progress over the last decade, it remains the leading cause of death worldwide. Liver cancers, including hepatocellular carcinoma (HCC), and liver metastases are distinct from other cancers in that they typically emerge as a consequence of long-term low-grade inflammation. Understanding the mechanisms that underpin inflammation-driven tissue remodeling of the hepatic immune environment is likely to provide new insights into much needed treatments for this devastating disease. Group 1 innate lymphoid cells (ILCs), which include natural killer (NK) cells and ILC1s, are particularly enriched in the liver and thought to contribute to the pathogenesis of a number of liver diseases, including cancer. NK cells are an attractive, but underexplored, therapeutic target in hepatic disease due to their role in immunosurveillance and their ability to recognize and eliminate malignant cells. ILC1s are closely related to and share many phenotypic features with NK cells but are less well studied. Thus, their utility in immunotherapeutic approaches is not yet well understood. Here, we review our current understanding of ILCs in cancer with a particular focus on liver and liver-related diseases.

Harnessing natural killer cells for cancer immunotherapy: dispatching the first responders

Natural killer (NK) cells have crucial roles in the innate immunosurveillance of cancer and viral infections. They are 'first responders' that can spontaneously recognize abnormal cells in the body, rapidly eliminate them through focused cytotoxicity mechanisms and potently produce pro-inflammatory cytokines and chemokines that recruit and activate other immune cells to initiate an adaptive response. From the initial discovery of the diverse cell surface receptors on NK cells to the characterization of regulatory events that control their function, our understanding of the basic biology of NK cells has improved dramatically in the past three decades. This advanced knowledge has revealed increased mechanistic complexity, which has opened the doors to the development of a plethora of exciting new therapeutics that can effectively manipulate and target NK cell functional responses, particularly in cancer patients. Here, we summarize the basic mechanisms that regulate NK cell biology, review a wide variety of drugs, cytokines and antibodies currently being developed and used to stimulate NK cell responses, and outline evolving NK cell adoptive transfer approaches to treat cancer.

NK Cells and Other Cytotoxic Innate Lymphocytes in Colorectal Cancer Progression and Metastasis

Colorectal cancer (CRC) is one of the most common malignancies and leading causes of cancer-related deaths worldwide. Despite its complex pathogenesis and progression, CRC represents a well-fitting example of how the immune contexture can dictate the disease outcome. The presence of cytotoxic lymphocytes, both CD8⁺ T cells and natural killer (NK) cells, represents a relevant prognostic factor in CRC and is associated with a better overall survival. Together with NK cells, other innate lymphocytes, namely, innate lymphoid cells (ILCs), have been found both in biopsies of CRC patients and in murine models of intestinal cancer, playing both pro- and anti-tumor activities. In particular, several type 1 innate lymphoid cells (ILC1) with cytotoxic functions have been recently described, and evidence in mice shows a role for both NK cells and ILC1 in controlling CRC metastasis. In this review, we provide an overview of the features of NK cells and the expanding spectrum of innate lymphocytes with cytotoxic functions. We also comment on both the described and the potential roles these innate lymphocytes can play during the progression of intestinal cancer leading to metastasis. Finally, we discuss recent advances in the molecular mechanisms underlying the functional regulation of cytotoxic innate lymphocytes in CRC.

Myeloid derived suppressor cells and innate immune system interaction in tumor microenvironment

The tumor microenvironment is a complex domain that not only contains tumor cells but also a plethora of other host immune cells. By nature, the tumor microenvironment is a highly immunosuppressive milieu providing growing conditions for tumor cells. A major immune cell population that contributes most in the development of this immunosuppressive microenvironment is the MDSC, a heterogenous population of immature cells. Although found in small numbers only in the bone marrow of healthy individuals, they readily migrate to the lymph nodes and tumor site during cancer pathogenesis. MDSC mediated disruption of antitumor T cell activity is a major cause of the immunosuppression at the tumor site, but recent findings have shown that MDSC mediated dysfunction of other major immune cells might also play an important role. In this article we will review how crosstalk with MDSC alters the activity of both conventional and unconventional immune cells that inhibits the antitumor immunity and promotes cancer progression.

SIGIRR Downregulation and Interleukin-1 Signaling Intrinsic to Renal Cell Carcinoma

Renal cell carcinoma is highly inflamed, and tumor cells are embedded into a microenvironment enriched with IL1. While inflammatory pathways are well characterized in the immune system, less is known about these same pathways in epithelial cells; it is unclear if and how innate immune signals directly impact on cancer cells, and if we could we manipulate these for therapeutic purposes. To address these questions, we first focused on the inflammatory receptors belonging to the IL1- and Toll-like receptor family including negative regulators in a small cohort of 12 clear cell RCC (ccRCC) patients’ samples as compared to their coupled adjacent normal tissues. Our data demonstrated that renal epithelial cancer cells showed a specific and distinctive pattern of inflammatory receptor expression marked by a consistent downregulation of the inhibitory receptor SIGIRR mRNA. This repression was confirmed at the protein level in both cancer cell lines and primary tissues. When we analyzed in silico data of different kidney cancer histotypes, we identified the clear cell subtype as the one where SIGIRR was mostly downregulated; nonetheless, papillary and chromophobe tumor types also showed low levels as compared to their normal counterpart. RNA-sequencing analysis demonstrated that IL1 stimulation of the ccRCC cell line A498 triggered an intrinsic signature of inflammatory pathway activation characterized by the induction of distinct “pro-tumor” genes including several chemokines, the autocrine growth factor IL6, the atypical co-transcription factor NFKBIZ, and the checkpoint inhibitor PD-L1. When we looked for the macroareas most represented among the differentially expressed genes, additional clusters emerged including pathways involved in cell differentiation, angiogenesis, and wound healing. To note, SIGIRR overexpression in A498 cells dampened IL1 signaling as assessed by a reduced induction of NFKBIZ. Our results suggest that SIGIRR downregulation unleashes IL1 signaling intrinsic to tumor cells and that manipulating this pathway may be beneficial in ccRCC.

MSLN Correlates With Immune Infiltration and Chemoresistance as a Prognostic Biomarker in Ovarian Cancer

Mesothelin (MSLN) is a glycoprotein with various expression degrees in different tumors including mesothelioma, ovarian cancer, pancreatic cancer, etc. MSLN is considered to play an important role in cell survival, proliferation, and tumor progression. Although the expression of MSLN in tumors makes it a potential therapeutic target, its mechanism of action is still unclear, especially its correlation with immune cells infiltration in the tumor microenvironment has not been investigated. In this study, we detected the overexpression of MSLN in ovarian cancer using database analysis and tissue-array staining. We further evaluated the diagnostic value of MSLN and found it was associated with poor overall survival in ovarian cancer. In addition, the high expression of MSLN was significantly related to the immune-related genes and chemoresistant genes. We confirmed the overexpression of MSLN in the chemoresistant ovarian cancer cell lines. Our research suggests that MSLN participates in a variety of pathways related to the suppression of immune activation and promotion of chemoresistance, leading to a poor prognosis in ovarian cancer.

The theory of tumor ecosystem

Cancer cells can be conceived as “living organisms” interacting with cellular or non‐cellular components in the host internal environment, not only the local tumor microenvironment but also the distant organ niches, as well as the immune, nervous and endocrine systems, to construct a self‐sustainable tumor ecosystem. With increasing evidence for the systemic tumor‐host interplay, we predict that a new era of cancer therapy targeting the ecosystemic vulnerability of human malignancies has come. Revolving around the tumor ecosystem scoped as different hierarchies of primary, regional, distal and systemic onco‐spheres, we comprehensively review the tumor‐host interaction among cancer cells and their local microenvironment, distant organ niches, immune, nervous and endocrine systems, highlighting material and energy flow with tumor ecological homeostasis as an internal driving force. We also substantiate the knowledge of visualizing, modelling and subtyping this dynamically intertwined network with recent technological advances, and discuss ecologically rational strategies for more effective cancer therapies.

Interleukin 1 receptor 8 deficiency does not impact atherosclerosis

No abstract.

Negative Regulation of the IL-1 System by IL-1R2 and IL-1R8: Relevance in Pathophysiology and Disease

Interleukin-1 (IL-1) is a primary cytokine of innate immunity and inflammation. IL-1 belongs to a complex family including ligands with agonist activity, receptor antagonists, and an anti-inflammatory cytokine. The receptors for these ligands, the IL-1 Receptor (IL-1R) family, include signaling receptor complexes, decoy receptors, and negative regulators. Agonists and regulatory molecules co-evolved, suggesting the evolutionary relevance of a tight control of inflammatory responses, which ensures a balance between amplification of innate immunity and uncontrolled inflammation. IL-1 family members interact with innate immunity cells promoting innate immunity, as well as with innate and adaptive lymphoid cells, contributing to their differentiation and functional polarization and plasticity. Here we will review the properties of two key regulatory receptors of the IL-1 system, IL-1R2, the first decoy receptor identified, and IL-1R8, a pleiotropic regulator of different IL-1 family members and co-receptor for IL-37, the anti-inflammatory member of the IL-1 family. Their complex impact in pathology, ranging from infections and inflammatory responses, to cancer and neurologic disorders, as well as clinical implications and potential therapeutic exploitation will be presented.

The Interleukin-1 (IL-1) Superfamily Cytokines and Their Single Nucleotide Polymorphisms (SNPs)

Interleukins (ILs)—which are important members of cytokines—consist of a vast group of molecules, including a wide range of immune mediators that contribute to the immunological responses of many cells and tissues. ILs are immune-glycoproteins, which directly contribute to the growth, activation, adhesion, differentiation, migration, proliferation, and maturation of immune cells; and subsequently, they are involved in the pro and anti-inflammatory responses of the body, by their interaction with a wide range of receptors. Due to the importance of immune system in different organisms, the genes belonging to immune elements, such as ILs, have been studied vigorously. The results of recent investigations showed that the genes pertaining to the immune system undergo progressive evolution with a constant rate. The occurrence of any mutation or polymorphism in IL genes may result in substantial changes in their biology and function and may be associated with a wide range of diseases and disorders. Among these abnormalities, single nucleotide polymorphisms (SNPs) can represent as important disruptive factors. The present review aims at concisely summarizing the current knowledge available on the occurrence, properties, role, and biological consequences of SNPs within the IL-1 family members.

IL-1R8 silencing improves the anti-tumor function of freshly isolated human NK cells

The inhibitory receptor interleukin-1 receptor 8 (IL-1R8) has been recently recognized to be expressed also by human natural killer (NK) cells. This study was aimed to design and optimize IL-1R8 silencing conditions in human NK cells to precisely establish the activity of such receptor in these cells. Electroporation of freshly isolated or IL-2-cultured NK cells with small interfering RNA (siRNA), resulted in a marked, even though variable, IL-1R8-silencing. Although the expression profile revealed downregulation of most genes involved in several intracellular pathways, some genes related to proliferation, expression of some chemokine receptors, antibody-dependent cell cytotoxicity and cytotoxic activity were upregulated in IL-1R8-silenced NK cells. Furthermore, upon IL-15 activation, the majority of genes involved in NK cell function were upregulated in IL-1R8-siRNA—compared with control—siRNA-transfected NK cells. More importantly, in agreement with these findings, the reduction of IL-1R8 gene expression levels resulted in enhanced expression of NK cell activation markers, production of cytokines and chemokines, and cytotoxic activity against several NK cell targets with different susceptibility to NK-mediated lysis. Similar results were obtained following stimulation with IL-18. All together these data, deeply impacting on the main effector functions of human NK cells, can lead to a better understanding of IL-1R8-mediated regulation on these cells and to the design of new strategies for improving NK cell-mediated anti-tumor responses.

Innate Immunity and Cancer Pathophysiology

Chronic inflammation increases the risk of several cancers, including gastric, colon, and hepatic cancers. Conversely, tumors, similar to tissue injury, trigger an inflammatory response coordinated by the innate immune system. Cellular and molecular mediators of inflammation modulate tumor growth directly and by influencing the adaptive immune response. Depending on the balance of immune cell types and signals within the tumor microenvironment, inflammation can support or restrain the tumor. Adding to the complexity, research from the past two decades has revealed that innate immune cells are highly heterogeneous and plastic, with variable phenotypes depending on tumor type, stage, and treatment. The field is now on the cusp of being able to harness this wealth of data to (a) classify tumors on the basis of their immune makeup, with implications for prognosis, treatment choice, and clinical outcome, and (b) design therapeutic strategies that activate antitumor immune responses by targeting innate immune cells.

Interleukin-37 promotes colitis-associated carcinogenesis via SIGIRR-mediated cytotoxic T cells dysfunction

Interleukin-37b (hereafter called IL-37) was identified as fundamental inhibitor of natural and acquired immunity. The molecular mechanism and function of IL-37 in colorectal cancer (CRC) has been elusive. Here, we found that IL-37 transgenic (IL-37tg) mice were highly susceptible to colitis-associated colorectal cancer (CAC) and suffered from dramatically increased tumor burdens in colon. Nevertheless, IL-37 is dispensable for intestinal mutagenesis, and CRC cell proliferation, apoptosis, and migration. Notably, IL-37 dampened protective cytotoxic T cell-mediated immunity in CAC and B16-OVA models. CD8⁺ T cell dysfunction is defined by reduced retention and activation as well as failure to proliferate and produce cytotoxic cytokines in IL-37tg mice, enabling tumor evasion of immune surveillance. The dysfunction led by IL-37 antagonizes IL-18-induced proliferation and effector function of CD8⁺ T cells, which was dependent on SIGIRR (single immunoglobulin interleukin-1 receptor-related protein). Finally, we observed that IL-37 levels were significantly increased in CRC patients, and positively correlated with serum CRC biomarker CEA levels, but negatively correlated with the CD8⁺ T cell infiltration in CRC patients. Our findings highlight the role of IL-37 in harnessing antitumor immunity by inactivation of cytotoxic T cells and establish a new defined inhibitory factor IL-37/SIGIRR in cancer-immunity cycle as therapeutic targets in CRC.

Polymorphonuclear Myeloid-Derived Suppressor Cells Are Abundant in Peripheral Blood of Cancer Patients and Suppress Natural Killer Cell Anti-Tumor Activity

Tumor microenvironment (TME) includes a wide variety of cell types and soluble factors capable of suppressing immune-responses. While the role of NK cells in TME has been analyzed, limited information is available on the presence and the effect of polymorphonuclear (PMN) myeloid-derived suppressor cells, (MDSC). Among the immunomodulatory cells present in TME, MDSC are potentially efficient in counteracting the anti-tumor activity of several effector cells. We show that PMN-MDSC are present in high numbers in the PB of patients with primary or metastatic lung tumor. Their frequency correlated with the overall survival of patients. In addition, it inversely correlated with low frequencies of NK cells both in the PB and in tumor lesions. Moreover, such NK cells displayed an impaired anti-tumor activity, even those isolated from PB. The compromised function of NK cells was consequent to their interaction with PMN-MDSC. Indeed, we show that the expression of major activating NK receptors, the NK cytolytic activity and the cytokine production were inhibited upon co-culture with PMN-MDSC through both cell-to-cell contact and soluble factors. In this context, we show that exosomes derived from PMN-MDSC are responsible of a significant immunosuppressive effect on NK cell-mediated anti-tumor activity. Our data may provide a novel useful tool to implement the tumor immunoscore. Indeed, the detection of PMN-MDSC in the PB may be of prognostic value, providing clues on the presence and extension of both adult and pediatric tumors and information on the efficacy not only of immune response but also of immunotherapy and, possibly, on the clinical outcome.

Challenges and Recent Advances in NK Cell-Targeted Immunotherapies in Solid Tumors

Natural killer (NK) cell is a powerful malignant cells killer, providing rapid immune responses via direct cytotoxicity without the need of antigen processing and presentation. It plays an essential role in preventing early tumor, metastasis and minimal residual disease. Although adoptive NK therapies achieved great success in clinical trials against hematologic malignancies, their accumulation, activation, cytotoxic and immunoregulatory functions are severely impaired in the immunosuppressive microenvironment of solid tumors. Now with better understandings of the tumor evasive mechanisms from NK-mediated immunosurveillance, immunotherapies targeting the key molecules for NK cell dysfunction and exhaustion have been developed and tested in both preclinical and clinical studies. In this review, we introduce the challenges that NK cells encountered in solid tumor microenvironment (TME) and the therapeutic approaches to overcome these limitations, followed by an outline of the recent preclinical advances and the latest clinical outcomes of NK-based immunotherapies, as well as promising strategies to optimize current NK-targeted immunotherapies for solid tumors.

The journey of SARS-CoV-2 in human hosts: a review of immune responses, immunosuppression, and their consequences

Coronavirus disease 2019 (COVID-19) is a highly infectious viral disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Laboratory findings from a significant number of patients with COVID-19 indicate the occurrence of leukocytopenia, specifically lymphocytopenia. Moreover, infected patients can experience contrasting outcomes depending on lymphocytopenia status. Patients with resolved lymphocytopenia are more likely to recover, whereas critically ill patients with signs of unresolved lymphocytopenia develop severe complications, sometimes culminating in death. Why immunodepression manifests in patients with COVID-19 remains unclear. Therefore, the evaluation of clinical symptoms and laboratory findings from infected patients is critical for understanding the disease course and its consequences. In this review, we take a logical approach to unravel the reasons for immunodepression in patients with COVID-19. Following the footprints of the virus within host tissues, from entry to exit, we extrapolate the mechanisms underlying the phenomenon of immunodepression.

Key Activating and Inhibitory Ligands Involved in the Mobilization of Natural Killer Cells for Cancer Immunotherapies

Natural killer (NK) cells are the most potent arm of the innate immune system and play an important role in immunity, alloimmunity, autoimmunity, and cancer. NK cells recognize “altered-self” cells due to oncogenic transformation or stress due to viral infection and target to kill them. The effector functions of NK cells depend on the interaction of the activating and inhibitory receptors on their surface with their cognate ligand expressed on the target cells. These activating and inhibitory receptors interact with major histocompatibility complex I (MHC I) expressed on the target cells and make decisions to mount an immune response. NK cell immune response includes cytolytic activity and secretion of cytokines to help with the ongoing immune response. The advancement of our knowledge on the expression of inhibitory and activating molecules led us to exploit these molecules in the treatment of cancer. This review discusses the importance of activating and inhibitory receptors on NK cells and their clinical importance in cancer immunotherapy.

The Biological Role and Therapeutic Potential of NK Cells in Hematological and Solid Tumors

NK cells are an attractive target for cancer immunotherapy due to their potent antitumor activity. The main advantage of using NK cells as cytotoxic effectors over T cells is a reduced risk of graft versus host disease. At present, several variants of NK-cell-based therapies are undergoing clinical trials and show considerable effectiveness for hematological tumors. In these types of cancers, the immune cells themselves often undergo malignant transformation, which determines the features of the disease. In contrast, the current use of NK cells as therapeutic agents for the treatment of solid tumors is much less promising. Most studies are at the stage of preclinical investigation, but few progress to clinical trials. Low efficiency of NK cell migration and functional activity in the tumor environment are currently considered the major barriers to NK cell anti-tumor therapies. Various therapeutic combinations, genetic engineering methods, alternative sources for obtaining NK cells, and other techniques are aiming at the development of promising NK cell anticancer therapies, regardless of tumorigenesis. In this review, we compare the role of NK cells in the pathogenesis of hematological and solid tumors and discuss current prospects of NK-cell-based therapy for hematological and solid tumors.

NLRP3 Inflammasome Mediates Immune-Stromal Interactions in Vasculitis

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The immunological and metabolic landscape in primary and metastatic liver cancer

The liver is the sixth most common site of primary cancer in humans, and generally arises in a background of cirrhosis and inflammation. Moreover, the liver is frequently colonized by metastases from cancers of other organs (particularly the colon) because of its anatomical location and organization, as well as its unique metabolic and immunosuppressive environment. In this Review, we discuss how the hepatic microenvironment adapts to pathologies characterized by chronic inflammation and metabolic alterations. We illustrate how these immunological or metabolic changes alter immunosurveillance and thus hinder or promote the development of primary liver cancer. In addition, we describe how inflammatory and metabolic niches affect the spreading of cancer metastases into or within the liver. Finally, we review the current therapeutic options in this context and the resulting challenges that must be surmounted.