Interleukin-37 mediates the antitumor activity in hepatocellular carcinoma: role for CD57+ NK cells

Spatial immune scoring system predicts hepatocellular carcinoma recurrence

Given the high recurrence rates of hepatocellular carcinoma (HCC) post-resection1-3, improved early identification of patients at high risk for post-resection recurrence would help to improve patient outcomes and prioritize healthcare resources4-6. Here we observed a spatial and HCC recurrence-associated distribution of natural killer (NK) cells in the invasive front and tumour centre from 61 patients. Using extreme gradient boosting and inverse-variance weighting, we developed the tumour immune microenvironment spatial (TIMES) score based on the spatial expression patterns of five biomarkers (SPON2, ZFP36L2, ZFP36, VIM and HLA-DRB1) to predict HCC recurrence risk. The TIMES score (hazard ratio = 88.2, P < 0.001) outperformed current standard tools for patient risk stratification including the TNM and BCLC systems. We validated the model in 231 patients from five multicentred cohorts, achieving a real-world accuracy of 82.2% and specificity of 85.7%. The predictive power of these biomarkers emerged through the integration of their spatial distributions, rather than individual marker expression levels alone. In vivo models, including NK cell-specific Spon2-knockout mice, revealed that SPON2 enhances IFNγ secretion and NK cell infiltration at the invasive front. Our study introduces TIMES, a publicly accessible tool for predicting HCC recurrence risk, offering insights into its potential to inform treatment decisions for early-stage HCC.

Cytokine biomarkers for independent prediction of hepatocellular carcinoma prognosis

Hepatocellular carcinoma (HCC) is a leading cause of cancer-related mortality worldwide. Although various therapeutic modalities have been established for HCC, the overall outcomes of patients after treatment remain unsatisfactory, highlighting the need for valuable independent prognostic biomarkers. Cytokines are a large group of multifunctional secretory proteins and play critical roles in regulating development and progression of many cancer types, including HCC. Moreover, the expression levels of many cytokines in tumor/peritumor tissues and serum/plasma samples have been validated as important biomarkers for independently predicting the prognosis of HCC patients. This review provides a comprehensive summary of literature evidence for the independent prognostic significance of cytokine biomarkers in HCC patients receiving different therapies.

The distinct roles of IL-37 and IL-38 in non-small cell lung carcinoma and their clinical implications

Lung cancer, a significant global health challenge, is primarily classified into non-small cell lung cancer (NSCLC) and small cell lung cancer. Despite advancements in targeted therapies and immunotherapies, NSCLC outcomes remain poor, with low five-year survival rates. Given the lung's constant exposure to the environment and the presence of mucosal-associated lymphoid tissues, immunity plays a crucial role in NSCLC development. Immune checkpoint inhibitors (ICIs) targeting PD-1/PD-L1 have shown promise. However, adverse immune events limit their efficacy. This review highlights the contrasting roles of IL-37 and IL-38 in NSCLC pathogenesis. IL-37, an anti-inflammatory cytokine, suppresses tumour growth. It achieves this by modulating macrophage polarization and dendritic cell maturation. Correlations between intra-tumoral IL-37 expression and improved survival suggest a protective role in NSCLC. This may be mediated through VEGF inhibition and immune regulation. Conversely, IL-38, while anti-inflammatory in certain contexts, exhibits a pro-tumorigenic role in NSCLC. IL-38 enhances tumour progression by increasing pro-inflammatory cytokine secretion and facilitating immune evasion, potentially through NF-κB signalling. Notably, IL-38 negatively regulates IL-37, further promoting tumorigenesis. Emerging data suggest that IL-37 has therapeutic potential in inhibiting NSCLC metastasis and supporting immune modulation. In contrast, IL-38 presents a potential target for mitigating pro-inflammatory microenvironment effects. The distinct roles of these cytokines emphasize the complex immune dynamics in NSCLC. Further exploration of their molecular mechanisms and therapeutic implications is warranted. Targeting IL-37 and IL-38 may offer novel strategies for enhancing NSCLC treatment outcomes.

Interleukin-37 exacerbates liver inflammation and promotes IFN-γ production in NK cells

Interleukin (IL)-37, a unique member of the IL-1 family, is known for its anti-inflammatory properties. However, its effects on immune-mediated liver diseases, such as primary biliary cholangitis (PBC) and acute immune-mediated hepatitis, remain unclear. Using mouse models of autoimmune cholangitis and hepatitis induced by 2-OA-OVA and concanavalin A (Con A) respectively, we introduced the human IL-37 gene via a liver-preferred adeno-associated virus vector (AAV-IL-37) to mice, as mice lack endogenous IL-37. Our findings reveal that IL-37 did not affect autoimmune cholangitis. Surprisingly, IL-37 exacerbated inflammation in Con A-induced hepatitis rather than mitigating it. Mechanistic insights suggest that this exacerbation involves the interferon (IFN)-γ pathway, supported by elevated serum IFN-γ levels in AAV-IL-37-treated Con A mice. Specifically, IL-37 heightened the number of hepatic NK and NKT cells, increased the production of the NK cell chemoattractant CCL5, and elevated the frequency of hepatic NK and NKT cells expressing IFN-γ. Moreover, IL-37 enhanced IFN-γ secretion from NK cells when combined with other proinflammatory cytokines, highlighting its synergistic effect in promoting IFN-γ production. These unexpected outcomes underscore a novel role for IL-37 in exacerbating liver inflammation during immune-mediated liver diseases, implicating its influence on NK cells and the production of IFN-γ by these cells.

The effect and mechanism of IL-37d on neutrophil recruitment in the early stage of tumor metastasis in the lungs

BACKGROUND

Chronic inflammation plays a pivotal role in cancer progression, with tumor-associated neutrophils (TANs) actively shaping the pre-metastatic niche. Interleukin-37 (IL-37), a known immunosuppressive cytokine, is implicated in this regulation, although its precise function remains underexplored.Therefore, this study seeks to further elucidate the inhibitory effect of IL-37d on neutrophil recruitment within the pre-metastatic lung microenvironment and its underlying mechanisms, thereby providing a theoretical foundation for clinical interventions in the early stages of cancer progression.

METHODS

This study investigates the impact of IL-37d on tumor growth, metastasis, and survival in a murine model, with a focus on the molecular mechanisms involved. Specifically, we explored IL-37d's ability to inhibit toll-like receptor 3 (TLR3) activation in lung epithelial cells, reduce calcium-binding proteins S100A8/A9 (S100a8/9) expression, and suppress matrix metalloproteinase 9 (MMP9) activity. We also examined IL-37d's effect on neutrophil migration from the bone marrow to the lungs during early metastasis.

RESULTS

IL-37d treatment significantly reduced lung metastasis and extended survival in mice. Mechanistically, IL-37d inhibited TLR3 activation, downregulated S100a8/9 expression, and reduced MMP9 activity, thereby impairing the migration of bone marrow-derived neutrophils to the lungs. This led to decreased neutrophil infiltration and a disruption of the pre-metastatic niche formation.

CONCLUSION

Our study represents the first investigation into the role of IL-37d in inhibiting tumor metastasis during the early stages by suppressing S100A8/9 and MMP9 expression in lung tissue, thereby reducing neutrophil recruitment and spontaneous migration from the bone marrow.

The role of IL-37 in gastrointestinal diseases

Gastrointestinal mucosal surface is frequently under challenge due to it's the large surface area and most common entry of microbes. IL-37, an anti-inflammatory cytokine, regulates local and systemic host immunity. H. pylori infection leads to the inhibition of IL-37 in the gastric mucosa, contributing to heightened mucosal inflammation and destruction, thereby facilitating increased proliferation of H. pylori. Food allergy, due to immune dysregulation, also contribute to GI injury. On the other hand, elevated levels of IL-37 observed in gastric cancer patients align with reduced host immunity at the cellular and humoral levels, indicating that IL-37 may contribute to the development of gastric cancer via suppressing pro-inflammatory responses. While IL-37 provides protection in an IBD animal model, the detection of highly produced IL-37 in IBD patients suggests a stage-dependent role, being protective in acute inflammation but potentially exacerbates the development of IBD in chronic conditions. Moreover, elevated colonic IL-37 in CRC correlates with overall survival time and disease time, indicating a protective role for IL-37 in CRC. The differential regulation and expression of IL-37 between upper- and lower-GI organs may be attributed to variations in the microbial flora. This information suggests that IL-37 could be a potential therapeutic agent, depending on the stage and location.

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.

The role of IL-36 and 37 in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) has garnered considerable attention due to its morbidity and mortality. Although the precise mechanisms underlying HCC tumorigenesis remain to be elucidated, evidence suggests that host immunity plays a pivotal role in its development. IL-36 and IL-37 are important immunoregulatory cytokines classified as pro-inflammatory and anti-inflammatory respectively. In the context of HCC, the downregulation of intrahepatic IL-36 is inversely correlated with cirrhosis, but positively correlated with 5-year survival rates, suggesting that IL-36 offers protection during HCC development. However, IL-36 may lose its hepatoprotective effects as the disease progresses to HCC in the context of dysregulated immunity in cirrhotic patients. Substantially increased circulating IL-36 in HCC patients is likely a systemic response to HCC stimulation, but is insufficient to suppress progression towards HCC. Intrahepatic IL-37 is suppressed in HCC patients, consistent with the inverse correlation between intrahepatic IL-37 and the level of AFP in HCC patients, suggesting IL-37 exerts hepatoprotection. There is no significant difference in IL-37 among differentiations of HCC or with respect to clinical BCLC stages or cirrhosis status in HCC patients. However, IL-37 protection is demonstrated in an IL-37 transfected HCC animal model, showing significantly reduced tumour size. IL-36/37 may inhibit HCC by enhancing M1 tumour-associated macrophages while not affecting M2 macrophages. The interplay between IL-36 (pro-inflammatory) and IL-37 (anti-inflammatory) is emerging as a crucial factor in host protection against the development of HCC. Further research is needed to investigate the complex mechanisms involved and the therapeutic potential of targeting these cytokines in HCC management.

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.

IL-1R8 expression in DLBCL regulates NK cell recruitment and influences patient prognosis

The precise biological function of Interleukin-1 receptor 8 (IL-1R8) in diffuse large B-cell lymphoma (DLBCL) is still not well understood. Our goal is to decipher the profile of IL-1R8 expression status in DLBCL and to explore how IL-1R8 is involved in DLBCL progression. Utilizing a tissue microarray consisting of 70 samples of DLBCL tumors alongside 15 samples of tonsillitis, our investigation revealed a parallel expression profile of IL-1R8 between the tumor tissues and tonsillitis samples (p > 0.05). Nevertheless, an intriguing association emerged, as heightened expression of IL-1R8 correlated significantly with unfavorable survival outcomes in patients with DLBCL (p < 0.05). The status of IL-1R8 expression did not directly regulate proliferation (p > 0.05) and apoptosis (p > 0.05) in DLBCL cells via CCK8 and apoptotic assays. Subsequent chemotaxis analysis indicated that natural killer (NK) cell recruitment could be suppressed by IL-1R8 signaling in DLBCL, at least partially through CXCL1 inhibition (p < 0.05). The status of IL-1R8 expression in tumor tissues exhibited a negative correlation with the density of CD57+ NK cell infiltration (p < 0.05), while it did not demonstrate a significant association with CD3+ T cells (p > 0.05), CD68+ macrophages (p > 0.05), or S-100+ dendritic cells (p > 0.05). In line with this observation, elevated levels of NK cell infiltration demonstrated a significant positive correlation with improved overall survival (OS) among patients diagnosed with DLBCL (p < 0.05). Our data suggests the immuno-regulating potential of IL-1R8 through NK cell recruitment in DLBCL, providing novel insights into future immuno-modulating therapies.

Novel insights into IL-37: an anti-inflammatory cytokine with emerging roles in anti-cancer process

Interleukin-37 (IL-37) is a newly discovered member of IL-1 family. The cytokine was proved to have extensive protective effects in infectious diseases, allergic diseases, metabolic diseases, autoimmune diseases and tumors since its discovery. IL-37 was mainly produced by immune and some non-immune cells in response to inflammatory stimulus. The IL-37 precursors can convert into the mature forms after caspase-1 cleavage and activation intracellularly, and then bind to Smad-3 and transfer to the nucleus to inhibit the production and functions of proinflammatory cytokines; extracellularly, IL-37 binds to cell surface receptors to form IL-37/IL-18Rα/IL-1R8 complex to exert immunosuppressive function via inhibiting/activating multiple signal pathways. In addition, IL-37 can attenuate the pro-inflammatory effect of IL-18 through directly or forming an IL-37/IL-18BP/IL-18Rβ complex. Therefore, IL-37 has the ability to suppress innate and acquired immunity of the host, and effectively control inflammatory stimulation, which was considered as a new hallmark of cancer. Specifically, it is concluded that IL-37 can inhibit the growth and migration of tumor cells, prohibit angiogenesis and mediate the immunoregulation in tumor microenvironment, so as to exert effective anti-tumor effects. Importantly, latest studies also showed that IL-37 may be a novel therapeutic target for cancer monitoring. In this review, we summarize the immunoregulation roles and mechanisms of IL-37 in anti-tumor process, and discuss its progress so far and potential as tumor immunotherapy.

Research Progress on the Role and Mechanism of IL-37 in Liver Diseases

Cytokines are important components of the immune system that can predict or influence the development of liver diseases. IL-37, a new member of the IL-1 cytokine family, exerts potent anti-inflammatory and immunosuppressive effects inside and outside cells. IL-37 expression differs before and after liver lesions, suggesting that it is associated with liver disease; however, its mechanism of action remains unclear. This article mainly reviews the biological characteristics of IL-37, which inhibits hepatitis, liver injury, and liver fibrosis by inhibiting inflammation, and inhibits the development of hepatocellular carcinoma (HCC) by regulating the immune microenvironment. Based on additional evidence, combining IL-37 with liver disease markers for diagnosis and treatment can achieve more significant effects, suggesting that IL-37 can be developed into a powerful tool for the clinical adjuvant treatment of liver diseases, especially HCC.

Interleukin-37 is involved in the immunopathogenesis of infectious mononucleosis

BACKGROUND

Multiple immunopathological responses to viruses are observed in infectious mononucleosis (IM), a manifestation of primary infection with Epstein-Barr virus (EBV). Protective effects of the negative immunoregulatory molecule interleukin-37 (IL-37) have been observed in various bacterial and viral infections. However, the function of IL-37 in IM remains unknown.

METHODS

Flow cytometry and enzyme-linked immunosorbent assay (ELISA) were used to determine the expression of IL-37 in the peripheral blood of patients diagnosed with IM, and the variation of lymphocyte subsets. Furthermore, the associations between IL-37 expression and the percentage of lymphocyte subgroups were analyzed.

RESULTS

Patients with IM had severe immune dysfunction. The control group had a lower expression of IL-37 than the patients with IM. There were significant associations between IL-37 expression and both the proportion of CD3⁺T cells and the ratio of CD3⁺CD4⁺ to CD3⁺CD8⁺T cells. Patients with higher levels of IL-37 expression had lower levels of the liver inflammation indicators, alanine aminotransferase (ALT) and aspartate aminotransferase (AST).

CONCLUSIONS

IL-37 may affect the immune pathogenesis of patients with IM infected with EBV, and may have immunotherapeutic benefit for EBV-associated illnesses.

Therapeutic Perspectives of IL1 Family Members in Liver Diseases: An Update

Interleukin (IL) 1 superfamily members are a cornerstone of a variety of inflammatory processes occurring in various organs including the liver. Progression of acute and chronic liver diseases regardless of etiology depends on the stage of hepatocyte damage, the release of inflammatory cytokines and disturbances in gut microbiota. IL1 cytokines and receptors can have pro- or anti-inflammatory roles, even dual functionalities conditioned by the microenvironment. Developing novel therapeutic strategies to block the IL1/IL1R signaling pathways seems like a reasonable option. This mode of action is now exploited by anakinra and canakinumab, which are used to treat different inflammatory illnesses, and studies in liver diseases are on the way. In this mini review, we have focused on the IL1 superfamily members, given their crucial role in liver inflammation diseases, specifically discussing their potential role in developing new treatment strategies.

Microbiome-Based Metabolic Therapeutic Approaches in Alcoholic Liver Disease

Alcohol consumption is a global healthcare problem. Chronic alcohol consumption generates a wide spectrum of hepatic lesions, the most characteristic of which are steatosis, hepatitis, fibrosis, and cirrhosis. Alcoholic liver diseases (ALD) refer to liver damage and metabolomic changes caused by excessive alcohol intake. ALD present several clinical stages of severity found in liver metabolisms. With increased alcohol consumption, the gut microbiome promotes a leaky gut, metabolic dysfunction, oxidative stress, liver inflammation, and hepatocellular injury. Much attention has focused on ALD, such as alcoholic fatty liver (AFL), alcoholic steatohepatitis (ASH), alcoholic cirrhosis (AC), hepatocellular carcinoma (HCC), a partnership that reflects the metabolomic significance. Here, we report on the global function of inflammation, inhibition, oxidative stress, and reactive oxygen species (ROS) mechanisms in the liver biology framework. In this tutorial review, we hypothetically revisit therapeutic gut microbiota-derived alcoholic oxidative stress, liver inflammation, inflammatory cytokines, and metabolic regulation. We summarize the perspective of microbial therapy of genes, gut microbes, and metabolic role in ALD. The end stage is liver transplantation or death. This review may inspire a summary of the gut microbial genes, critical inflammatory molecules, oxidative stress, and metabolic routes, which will offer future promising therapeutic compounds in ALD.

The intellectual base and research fronts of IL-37: A bibliometric review of the literature from WoSCC

Background

IL-37 is a recently identified cytokine with potent immunosuppressive functions. The research fronts of IL-37 are worth investigating, and there is no bibliometric analysis in this field. The purpose of this study is to construct the intellectual base and predict research hotspots of IL-37 research both quantitatively and qualitatively according to bibliometric analysis.

Methods

The articles were downloaded from the Web of Science Core Collection (WoSCC) database from the inception of the database to 1 April 2022. CiteSpace 5.8.R3 (64-bit, Drexel University, Philadelphia, PA, USA) and Online Analysis Platform of Literature Metrology (https://bibliometric.com/) were used to perform bibliometric and knowledge-map analyses.

Results

A total of 534 papers were included in 200 academic journals by 2,783 authors in 279 institutions from 50 countries/regions. The journal Cytokine published the most papers on IL-37, while Nature Immunology was the most co-cited journal. The publications belonged mainly to two categories of Immunology and Cell Biology. USA and China were the most productive countries. Meanwhile, the University of Colorado Denver in USA produced the highest number of publications followed by Radboud University Nijmegen in the Netherlands and Monash University in Australia. Charles A. Dinarello published the most papers, while Marcel F. Nold had the most co-citations. Top 10 co-citations on reviews, mechanisms, and diseases were regarded as the knowledge base. The keyword co-occurrence and co-citations of references revealed that the mechanisms and immune-related disorders were the main aspects of IL-37 research. Notably, the involvement of IL-37 in various disorders and the additional immunomodulatory mechanisms were two emerging hotspots in IL-37 research.

Conclusions

The research on IL-37 was thoroughly reviewed using bibliometrics and knowledge-map analyses. The present study is a benefit for academics to master the dynamic evolution of IL-37 and point out the direction for future research.

Expression of IL-37 Correlates With Immune Cell Infiltrate and Fibrosis in Pediatric Autoimmune Liver Diseases

OBJECTIVES

The activation of innate immune mechanisms is key for chronic liver injury. Interleukin-37 (IL-37) is a profound inhibitor of innate and adaptive immune responses, and its overexpression protects mice from liver inflammation and fibrosis. Here, we characterize the hepatic inflammatory infiltrate and expression of IL-37 in children with autoimmune liver diseases.

METHODS

We compared the inflammatory microenvironment of the liver in a retrospective cohort of children with primary sclerosing cholangitis (PSC), autoimmune sclerosing cholangitis (ASC) and autoimmune hepatitis (AIH) by immunohistochemistry. The expression of IL-37 was quantified in liver parenchyma and portal tracts. Double immunofluorescence was used for detection of IL-37 in specific cell types and colocalization with Smad3.

RESULTS

AIH is characterized by a dense lymphoplasmacytic infiltrate whereas ASC shows high numbers of granulocytes in portal tracts. IL-37 expression correlates positively with liver inflammation and fibrosis, the number of infiltrating immune cells and serum markers for hepatic inflammation. IL-37 is mainly expressed in hepatocytes, cholangiocytes and infiltrating immune cells. Double staining revealed IL-37 positivity in T helper and regulatory T cells (Treg), Kupffer (KC) and hepatic stellate cells (HSC). IL-37 colocalizes with intranuclear pSmad3L in areas of liver inflammation.

CONCLUSIONS

Pediatric ASC separates from PSC and AIH by a granulocyte-rich portal infiltrate. Upregulation of IL-37 with liver injury, the expression in Treg as well as KC and HSC and the colocalization of IL-37 with pSmad3L in cholangiocytes and hepatocytes suggest a modulating role to limit hepatic inflammation and fibrosis in pediatric autoimmune liver diseases.

The Prognostic Value of Natural Killer Cells and Their Receptors/Ligands in Hepatocellular Carcinoma: A Systematic Review and Meta-Analysis

Background

Natural killer (NK) cells play major roles in eliminating tumor cells. Preliminary studies have shown that NK cells and their receptors/ligands have prognostic value in malignant tumors. However, the relevance of NK cells and their receptors/ligands level to the prognosis of hepatocellular carcinoma (HCC) remains unclear.

Methods

Several electronic databases were searched from database inception to November 8, 2021. Random effects were introduced to this meta-analysis. The relevance of NK cells and their receptors/ligands level to the prognosis of HCC was evaluated using hazard ratios (HRs) with 95% confidence interval (95%CI).

Results

26 studies were included in the analysis. The pooled results showed that high NK cells levels were associated with better overall survival (HR=0.70, 95%CI 0.57–0.86, P=0.001) and disease-free survival (HR=0.61, 95%CI 0.40-0.93, P=0.022) of HCC patients. In subgroup analysis for overall survival, CD57⁺ NK cells (HR=0.70, 95%CI 0.55-0.89, P=0.004) had better prognostic value over CD56⁺ NK cells (HR=0.69, 95%CI 0.38-1.25, P=0.224), and intratumor NK cells had better prognostic value (HR=0.71, 95%CI 0.55-0.90, P=0.005) over peripheral NK cells (HR=0.66, 95%CI 0.41-1.06, P=0.088). In addition, high level of NK cell inhibitory receptors predicted increased recurrence of HCC, while the prognostic role of NK cell activating receptors remained unclear.

Conclusion

NK cells and their inhibitory receptors have prognostic value for HCC. The prognostic role of NK cell activating receptors is unclear and more high-quality prospective studies are essential to evaluate the prognostic value of NK cells and their receptors/ligands for HCC.

The Role of IL-37 and IL-38 in Colorectal Cancer

Colorectal cancer (CRC) is a major killer. Dysregulation of IL-37 and IL-38, both anti-inflammatory cytokines, is observed in auto-immune diseases. The precise regulatory mechanisms of IL-37/IL-38 during the development of CRC remains unclear, but chronic intestinal inflammation is involved in the carcinogenesis of CRC. Constitutive production of colonic IL-37 and IL-38 is substantially reduced in CRC, consistent with an inverse correlation with CRC differentiation. Reduced colonic IL-37 and IL-38 is relating to CRC invasion and distant metastasis, suggesting a protective role for IL-38 within the tumor micro-environment. IL-38 is reduced in right-sided CRC compared to left-sided CRC, which is in line with multiple risk factors for right-sided CRC, including the embryonic development of the colon, and genetic differences in CRC between these two sides. Finally, colonic IL-37 and tumor associated neutrophils (TAN) seem to be independent biomarkers of prognostic value, whereas colonic IL-38 seems to be a reliable and independent biomarker in predicting the 5-year survival post-surgery in CRC. However, there is room for improvement in available studies, including the extension of these studies to different regions/countries incorporating different races, evaluation of the role of multi-drug resistance, and different subsets of CRC. It would be useful to determine the kinetics of circulating IL-38 and its relationship with drug resistance/targeted therapy. The measurement of colonic IL-38 at the molecular and cellular level is required to explore the contribution of IL-38 pathways during the development of CRC. These approaches could provide insight for the development of personalized medicine.

Dual role of IL-37 in the progression of tumors

Interleukin (IL)-37 is a novel defined cytokine that belongs to IL-1 family, which possesses potent anti-inflammatory and immunosuppressive properties. The IL-37 protein mainly exists in the cytoplasm of monocytes and is also expressed in epithelial cells and T cells. IL-37 is produced as a precursor which works in mature or immature isoforms without a classic signal peptide, and negatively regulates TLR agonist- mediated signaling pathway, proinflammatory cytokines, and IL-1R ligands. IL-37 has been found to be elevated and plays an anti-tumor role in various types of tumors, such as hepatocellular carcinoma, non-small cell lung cancer, and cervical cancer. The tumor microenvironment (TME) refers to the cellular environment where the tumor or cancer stem cells exist. At present, growing evidence shows that changes in TME can regulate metabolism, immunity, secretion, and function, so as to inhibit or promote the progression of the tumor. Therefore, a thorough understanding of the TME is essential for the occurrence and development of tumors. In this review, we will summarize the role of IL-37 in the microenvironment of different tumors, hoping to provide novel perspectives towards the mechanism, prevention, and treatment of tumors.

The interleukin-1 cytokine family members: Role in cancer pathogenesis and potential therapeutic applications in cancer immunotherapy

The interleukin-1 (IL-1) family is one of the first described cytokine families and consists of eight cytokines (IL-1β, IL-1α, IL-18, IL-33, IL-36α, IL-36β, IL-36γ and IL-37) and three receptor antagonists (IL-1Ra, IL-36Ra and IL-38). The family members are known to play an essential role in inflammation. The importance of inflammation in cancer has been well established in the past decades. This review sets out to give an overview of the role of each IL-1 family member in cancer pathogenesis and show their potential as potential anticancer drug candidates. First, the molecular structure is described. Next, both the pro- and anti-tumoral properties are highlighted. Additionally, a critical interpretation of current literature is given. To conclude, the IL-1 family is a toolbox with a collection of powerful tools that can be considered as potential drugs or drug targets.

IL-10 and Its Related Superfamily Members IL-19 and IL-24 Provide Parallel/Redundant Immune-Modulation in Loa loa Infection

BACKGROUND

Interleukin-10 (IL-10) has been implicated as the major cytokine responsible for the modulation of parasite-specific responses in filarial infections; however, the role of other IL-10 superfamily members in filarial infection is less well studied.

METHODS

Peripheral blood mononuclear cells from loiasis patients were stimulated with or without filarial antigen. Cytokine production was quantified using a Luminex platform and T-cell expression patterns were assessed by flow cytometry.

RESULTS

All patients produced significant levels of IL-10, IL-13, IL-5, IL-4, and IL-9 in response to filarial antigen, indicating a common infection-driven response. When comparing microfilaria (mf)-positive and mf-negative patients, there were no significant differences in spontaneous cytokine nor in parasite-driven IL-10, IL-22, or IL-28a production. In marked contrast, mf-positive individuals had significantly increased filarial antigen-driven IL-24 and IL-19 compared to mf-negative subjects. mf-positive patients also demonstrated significantly higher frequencies of T cells producing IL-19 in comparison to mf-negative patients. T-cell expression of IL-19 and IL-24 was positively regulated by IL-10 and IL-1β. IL-24 production was also regulated by IL-37.

CONCLUSION

These data provide an important link between IL-10 and its related family members IL-19 and IL-24 in the modulation of the immune response in human filarial infections.

CLINICAL TRIALS REGISTRATION

NCT00001230.

Interleukin-37b inhibits the growth of murine endometriosis-like lesions by regulating proliferation, invasion, angiogenesis and inflammation

Endometriosis is a gynecological disease with abnormal expression of interleukin (IL)-37 which can suppress inflammation and the immune system. Here we investigated the role of the IL-37b splice variant in endometriosis in vivo and in vitro. In a murine model of endometriosis, in vivo administration of IL-37b significantly inhibited the development of lesions judged by the number (P = 0.0213), size (P = 0.0130) and weight (P = 0.0152) of lesions. IL-37b had no effect on the early stage of lesion formation, however administration in the growth stage of lesions decreased the number (P = 0.0158), size (P = 0.0158) and weight (P = 0.0258) of lesions compared with PBS control, an effect that was not reversed by macrophage depletion. Expressions of inflammatory factors, matrix metalloproteinases and vascular endothelial growth factor-A mRNA/protein were significantly inhibited in ectopic lesions following IL-37b administration, and in uterine segments treated in vitro. In vitro treatment of uterine segments with IL-37b inhibited phosphorylation of Akt and Erk1/2 in uterine segments. Isolated mouse endometrial stromal treated with IL-37b and transfected with pIL-37b plasmid got suppressed cell proliferation, invasion, angiogenesis and the expression of inflammatory factors. In addition, transfection with pIL-37b significantly decreased the phosphorylation of Akt and Erk1/2. IL-37b also inhibited proliferation and the expression of inflammatory and angiogenesis factors in epithelial cell line RL95-2. These findings suggest that IL-37b may inhibit the growth of lesions by regulating proliferation, invasion, angiogenesis and inflammation through Akt and Erk1/2 signaling pathway.

Reduced IL-37 gene expression and CD8 T lymphocytes in patients with metastatic breast cancer

BACKGROUND

However, the exact immunopathological mechanisms in the progression of breast cancer are not clearly understood, various factors including CD8 T lymphocytes have lethal properties on tumor cells. On the other hand, interleukin-37 (IL-37), as a new member of the IL-1 family, is an anti-inflammatory cytokine; however, the exact role of IL-37 in breast cancer has not yet been determined.

OBJECTIVE

This study aimed to evaluate the CD8 T lymphocytes count and IL-37 gene expression in newly diagnosed breast cancer patients with and without metastasis.

METHODS

In this study, blood samples from 36 metastatic and 36 non-metastatic breast cancer patients and 36 healthy individuals as control were collected. After RNA extraction and cDNA synthesis, the relative gene expression was performed using real-time PCR. Also, counting the CD8 T lymphocytes was done by flow cytometry technique.

RESULTS

The results of this study showed that the gene expression of IL-37 in blood samples of metastatic and non-metastatic breast cancer patients was significantly lower than in healthy individuals (P < 0.05). The relative gene expression of the IL-37 in ER+/PR+/HER2+ patients with non-metastatic breast cancer had a significant increase compared to HER2+ patients (P < 0.05). Also, CD8 T lymphocytes count in the samples of patients including non-metastatic and metastatic breast cancer was significantly decreased compared to the healthy individuals (P < 0.05).

CONCLUSIONS

Our findings provide evidence that IL-37 gene expression and CD8 T lymphocytes count, significantly decreased in non-metastatic and metastatic breast cancer. Considering the possible effects of IL-37 on TCD8 cells in tumor immune responses, more research will be done to benefit from the therapeutic effects of this cytokine in the future.

IL-37 Was Involved in Progress of Acute Myeloid Leukemia Through Regulating IL-6 Expression

Background

Interleukin-37, which was discovered in 2000, is a natural suppressor of immune and inflammatory responses. Recent studies reported that IL-37 was abnormally expressed in several tumor patients, including those with hepatocellular carcinoma, gastric cancer, lung cancer, colon cancer, epithelial ovarian cancer, and multiple myeloma. However, the expression and potential function of IL-37 in leukemia remain unknown.

Objective

The aim of this study was to evaluate IL-37 as a prognostic factor and its possible mechanism of action.

Methods

Polymerase chain reaction products were analyzed by agarose gel electrophoresis and were purified and subsequently sequenced by a genetic testing laboratory. Human PBMC was purified from whole blood samples by using Ficoll-Paque PLUS. The concentrations of human IL-37 and human IL-6 were measured using enzyme-linked immunosorbent assay (ELISA) kits.

Results

IL-37, especially isoform b and d, was expressed in the bone marrow of AML, CML, ALL, and CLL. Importantly, IL-37 expression was downregulated in newly diagnosed AML patients and restored in patients in complete remission. Moreover, a significant association was found between IL-37 expression and NPM1 mutation or possible prognosis evaluated by karyotype and gene mutation. Further analysis revealed that IL-37 expression was negatively correlated with IL-6 expression. With regard to the mechanism, recombinant human IL-37 could suppress IL-6 expression stimulated by LPS in PBMC of AML patients.

Conclusion

Our study suggested that IL-37 may be an important prognostic factor in AML and is involved in AML via the IL-6 signaling pathway, indicating that IL-37 is an innovative research strategy for AML pathogenesis and therapy.

The Effect of Unconventional Cytokine Combinations on NK-Cell Responses to Viral Infection

Cytokines are soluble and membrane-bound factors that dictate immune responses. Dogmatically, cytokines are divided into families that promote type 1 cell-mediated immune responses (e.g., IL-12) or type 2 humoral responses (e.g., IL-4), each capable of antagonizing the opposing family of cytokines. The discovery of additional families of cytokines (e.g., IL-17) has added complexity to this model, but it was the realization that immune responses frequently comprise mixtures of different types of cytokines that dismantled this black-and-white paradigm. In some cases, one type of response may dominate these mixed milieus in disease pathogenesis and thereby present a clear therapeutic target. Alternatively, synergistic or blended cytokine responses may obfuscate the origins of disease and perplex clinical decision making. Most immune cells express receptors for many types of cytokines and can mediate a myriad of functions important for tolerance, immunity, tissue damage, and repair. In this review, we will describe the unconventional effects of a variety of cytokines on the activity of a prototypical type 1 effector, the natural killer (NK) cell, and discuss how this may impact the contributions of these cells to health and disease.

IL-1 Family Antagonists in Mouse and Human Skin Inflammation

Interleukin (IL)-1 family cytokines initiate inflammatory responses, and shape innate and adaptive immunity. They play important roles in host defense, but excessive immune activation can also lead to the development of chronic inflammatory diseases. Dysregulated IL-1 family signaling is observed in a variety of skin disorders. In particular, IL-1 family cytokines have been linked to the pathogenesis of psoriasis and atopic dermatitis. The biological activity of pro-inflammatory IL-1 family agonists is controlled by the natural receptor antagonists IL-1Ra and IL-36Ra, as well as by the regulatory cytokines IL-37 and IL-38. These four anti-inflammatory IL-1 family members are constitutively and highly expressed at steady state in the epidermis, where keratinocytes are a major producing cell type. In this review, we provide an overview of the current knowledge concerning their regulatory roles in skin biology and inflammation and their therapeutic potential in human inflammatory skin diseases. We further highlight some common misunderstandings and less well-known observations, which persist in the field despite recent extensive interest for these cytokines.

Modulation of Liver Inflammation and Fibrosis by Interleukin-37

Background and Aims: Chronic inflammation induces liver fibrosis, cirrhosis and potentially liver cancer. Kupffer cells modulate hepatic stellate cells by secreting immunologically active proteins as TGF-β. TGF-β promotes liver fibrosis via the activation of Sma- and Mad-related protein 3. IL-37 broadly suppresses innate and adaptive immune responses. Intracellular IL-37 interacts with Smad3. We hypothesize that IL-37 downregulates the activation of hepatic Kupffer and stellate cells and interferes with the TGF-β signaling cascade to modulate liver fibrogenesis. Methods: The role of IL-37 on liver inflammation and fibrogenesis was assessed in three mouse models as well as isolated Kupffer- and stellate cells. Serum IL-37 was tested by ELISA in a clinical cohort and correlated with liver disease severity. Results: Transgene expression of IL-37 in mice extends survival, reduces hepatic damage, expression of early markers of fibrosis and histologically assessed liver fibrosis after bile duct ligation. IL-37tg mice were protected against CCl4-induced liver inflammation. Colitis-associated liver inflammation and fibrosis was less severe in IL-10 knockout IL-37tg mice. Spontaneous and LPS/TGF-β-induced cytokine release and profibrogenic gene expression was lower in HSC and KC isolated from IL-37tg mice and IL-37 overexpressing, IL-1β stimulated human LX-2 stellate cells. However, administration of recombinant human IL-37 did not modulate fibrosis pathways after BDL in mice, LX2 cells or murine HSCs. In a large clinical cohort, we observed a positive correlation of serum IL-37 levels with disease severity in liver cirrhosis. Conclusions: Predominantly intracellular IL-37 downregulates liver inflammation and fibrosis. The correlation of serum IL-37 with disease severity in cirrhosis suggests its potential as a novel target modulating the course of liver fibrosis.

"Complimenting the Complement": Mechanistic Insights and Opportunities for Therapeutics in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the most common primary malignancy of the liver and a leading cause of death in the US and worldwide. HCC remains a global health problem and is highly aggressive with unfavorable prognosis. Even with surgical interventions and newer medical treatment regimens, patients with HCC have poor survival rates. These limited therapeutic strategies and mechanistic understandings of HCC immunopathogenesis urgently warrant non-palliative treatment measures. Irrespective of the multitude etiologies, the liver microenvironment in HCC is intricately associated with chronic necroinflammation, progressive fibrosis, and cirrhosis as precedent events along with dysregulated innate and adaptive immune responses. Central to these immunological networks is the complement cascade (CC), a fundamental defense system inherent to the liver which tightly regulates humoral and cellular responses to noxious stimuli. Importantly, the liver is the primary source for biosynthesis of >80% of complement components and expresses a variety of complement receptors. Recent studies implicate the complement system in liver inflammation, abnormal regenerative responses, fibrosis, carcinogenesis, and development of HCC. Although complement activation differentially promotes immunosuppressive, stimulant, and angiogenic microenvironments conducive to HCC development, it remains under-investigated. Here, we review derangement of specific complement proteins in HCC in the context of altered complement regulatory factors, immune-activating components, and their implications in disease pathogenesis. We also summarize how complement molecules regulate cancer stem cells (CSCs), interact with complement-coagulation cascades, and provide therapeutic opportunities for targeted intervention in HCC.

Interleukin-37 improves T-cell-mediated immunity and chimeric antigen receptor T-cell therapy in aged backgrounds

Aging‐associated declines in innate and adaptive immune responses are well documented and pose a risk for the growing aging population, which is predicted to comprise greater than 40 percent of the world's population by 2050. Efforts have been made to improve immunity in aged populations; however, safe and effective protocols to accomplish this goal have not been universally established. Aging‐associated chronic inflammation is postulated to compromise immunity in aged mice and humans. Interleukin‐37 (IL‐37) is a potent anti‐inflammatory cytokine, and we present data demonstrating that IL‐37 gene expression levels in human monocytes significantly decline with age. Furthermore, we demonstrate that transgenic expression of interleukin‐37 (IL‐37) in aged mice reduces or prevents aging‐associated chronic inflammation, splenomegaly, and accumulation of myeloid cells (macrophages and dendritic cells) in the bone marrow and spleen. Additionally, we show that IL‐37 expression decreases the surface expression of programmed cell death protein 1 (PD‐1) and augments cytokine production from aged T‐cells. Improved T‐cell function coincided with a youthful restoration of Pdcd1, Lat, and Stat4 gene expression levels in CD4⁺ T‐cells and Lat in CD8⁺ T‐cells when aged mice were treated with recombinant IL‐37 (rIL‐37) but not control immunoglobin (Control Ig). Importantly, IL‐37‐mediated rejuvenation of aged endogenous T‐cells was also observed in aged chimeric antigen receptor (CAR) T‐cells, where improved function significantly extended the survival of mice transplanted with leukemia cells. Collectively, these data demonstrate the potency of IL‐37 in boosting the function of aged T‐cells and highlight its therapeutic potential to overcome aging‐associated immunosenescence.

The role of natural killer cell in gastrointestinal cancer: killer or helper

Gastrointestinal cancer is one of the leading health problems worldwide, with a high morbidity and mortality. To date, harnessing both the innate and adaptive immune system against cancer provides a selective and effective therapeutic strategy for patients. As a first line defense against cancer, natural killer (NK) cells can swiftly target and lyse tumor cells without prior activation. In addition to its pivotal role in innate immunity, NK cells also play unique roles in the adaptive immune system as it enhance anti-tumor adaptive immune responses through secretion of cytokines and retaining an immunological memory. All these characteristics make NK cell a promising anti-cancer agent for patients. In spite of scarce infiltration and impaired function of NK cells in tumors, and the fact that tumors easily develop resistant mechanisms to evade the attacks from endogenous NK cells, multiple strategies have been developed to boost anti-tumor effect of NK cells and abolish tumor resistance. Some examples include adoptive transfer of NK cells after ex vivo activation and expansion; restoration of NK cell function using immune checkpoint inhibitors, and monoclonal antibody or cytokine treatment. Preclinical data have shown encouraging results, suggesting that NK cells hold great potential in cancer therapy. In this review, we discuss NK cells' cytotoxicity and modulation function in GI cancer and the current application in clinical therapy.

Targeting MARCO and IL37R on Immunosuppressive Macrophages in Lung Cancer Blocks Regulatory T Cells and Supports Cytotoxic Lymphocyte Function

The progression and metastatic capacity of solid tumors are strongly influenced by immune cells in the tumor microenvironment. In non-small cell lung cancer (NSCLC), accumulation of anti-inflammatory tumor-associated macrophages (TAM) is associated with worse clinical outcome and resistance to therapy. Here we investigated the immune landscape of NSCLC in the presence of protumoral TAMs expressing the macrophage receptor with collagenous structure (MARCO). MARCO-expressing TAM numbers correlated with increased occurrence of regulatory T cells and effector T cells and decreased natural killer (NK) cells in these tumors. Furthermore, transcriptomic data from the tumors uncovered a correlation between MARCO expression and the anti-inflammatory cytokine IL37. In vitro studies subsequently showed that lung cancer cells polarized macrophages to express MARCO and gain an immune-suppressive phenotype through the release of IL37. MARCO-expressing TAMs blocked cytotoxic T-cell and NK-cell activation, inhibiting their proliferation, cytokine production, and tumor killing capacity. Mechanistically, MARCO⁺ macrophages enhanced regulatory T (Treg) cell proliferation and IL10 production and diminished CD8 T-cell activities. Targeting MARCO or IL37 receptor (IL37R) by antibody or CRISPR knockout of IL37 in lung cancer cell lines repolarized TAMs, resulting in recovered cytolytic activity and antitumoral capacity of NK cells and T cells and downmodulated Treg cell activities. In summary, our data demonstrate a novel immune therapeutic approach targeting human TAMs immune suppression of NK- and T-cell antitumor activities. SIGNIFICANCE: This study defines tumor-derived IL37 and the macrophage scavenger receptor MARCO as potential therapeutic targets to remodel the immune-suppressive microenvironment in patients with lung cancer. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/81/4/956/F1.large.jpg.

NK cell infiltration is associated with improved overall survival in solid cancers: A systematic review and meta-analysis

The immune landscape of a tumor is highly connected to patient prognosis and response to treatment, but little is known about how natural killer (NK) cells predict overall survival (OS) among patients with solid tumors. We present the first meta-analysis on NK cell infiltration into solid tumors as a prognostic indicator for OS, considering cancer types independently, and together. Samples were collected from 1973 to 2016 with results published between 1989 and 2020. From 53 studies, we found that NK cell infiltration corresponds with decreased risk of death (HR=0.34, 95% CI: 0.26-0.46; p<0.0001). Among studies that investigated the prognostic potential of NK cells in specific regions of the tumor, intraepithelial infiltration was better predictive of OS than NK infiltration in the tumor-adjacent stroma. Generally, NK cell infiltration is lower in advanced-stage and lower-grade tumors; nevertheless, it remains prognostically beneficial. This meta-analysis highlights an important prognostic role of NK cells in solid tumors, but exposes that few studies have considered the contributions of NK cells. Toward NK cell-based immunotherapies, it will be important to understand the conditions under which NK cells can be effective agents of tumor control.

The Crosstalk Between Tumor-Associated Macrophages (TAMs) and Tumor Cells and the Corresponding Targeted Therapy

Tumor microenvironment (TME) is composed of tumor cells and surrounding non-tumor stromal cells, mainly including tumor associated macrophages (TAMs), endothelial cells, and carcinoma-associated fibroblasts (CAFs). The TAMs are the major components of non-tumor stromal cells, and play an important role in promoting the occurrence and development of tumors. Macrophages originate from bone marrow hematopoietic stem cells and embryonic yolk sacs. There is close crosstalk between TAMs and tumor cells. With the occurrence of tumors, tumor cells secrete various chemokines to recruit monocytes to infiltrate tumor tissues and further promote their M2-type polarization. Importantly, M2-like TAMs can in turn accelerate tumor growth, promote tumor cell invasion and metastasis, and inhibit immune killing to promote tumor progression. Therefore, targeting TAMs in tumor tissues has become one of the principal strategies in current tumor immunotherapy. Current treatment strategies focus on reducing macrophage infiltration in tumor tissues and reprogramming TAMs to M1-like to kill tumors. Although these treatments have had some success, their effects are still limited. This paper mainly summarized the recruitment and polarization of macrophages by tumors, the support of TAMs for the growth of tumors, and the research progress of TAMs targeting tumors, to provide new treatment strategies for tumor immunotherapy.

Elevated serum levels of interleukin-37 correlate with poor prognosis in gastric cancer

BACKGROUND

interleukin-37 (IL-37) is as a natural suppressor of the innate inflammatory and immune responses. It has also been reported to be involved in carcinogenesis and metastasis. The present case-control study was designed to investigate the role of serum levels of IL-37 in patients with gastric cancer.

METHODS

serum IL-37 levels were determined using the enzyme-linked immunosorbent assay in 180 patients diagnosed with gastric cancer and 100 healthy controls. The association between IL-37 levels and clinical factors was assessed. Univariate and multivariate analyses were performed to investigate the prognostic significance of these parameters in gastric cancer.

RESULTS

serum IL-37 levels in gastric cancer patients (5.606 ± 0.837 pg/ml) were significantly higher than those in healthy controls (2.364 ± 0.210 pg/ml, p < 0.001). High serum IL-37 levels were related to a poorly differentiated histologic type (p = 0.046) and advanced T stage (p = 0.003). The Kaplan-Meier survival analysis indicated that the high-IL-37 group had a poorer overall survival and progression-free survival (overall survival [OS]: 39.0 months vs 13.0 months, p < 0.001, progression-free survival [PFS]: 25.0 months vs 10.0 months, p < 0.001). Multivariate analyses showed serum IL-37 to be an independent prognostic factor for gastric cancer patients (OS: hazard ratios [HR] = 1.842, 95% CI: 1.190-2.854, p = 0.006; PFS: HR = 1.547, 95% CI: 1.014-2.359, p = 0.043).

CONCLUSIONS

in conclusion, serum IL-37 levels were associated with poor overall survival and progression-free survival in gastric cancer patients. IL-37 may be a potential predictor of prognosis in gastric cancer.

Prognostic Significance of Tumor-Infiltrating Natural Killer Cells in Solid Tumors: A Systematic Review and Meta-Analysis

Background: Tumor-infiltrating natural killer (NK) cells (TINKs) are crucial immune cells in tumor defense, and might be related to tumor prognosis. However, the results were discrepant among different studies. The present meta-analysis was performed to comprehensively assess the prognostic value of NK cell markers in solid tumor tissues.

Methods: PubMed, Web of Science, and EMBASE were searched to identify original researches reporting the prognostic significance of TINKs in solid tumors. NK cell markers CD56, CD57, NKp30, and NKp46 were included in the analysis. The hazard ratios (HRs) and 95% confidence intervals (CIs) of pooled overall survival (OS), disease-free survival (DFS), metastasis-free survival (MFS), progression-free survival (PFS), and recurrence-free survival (RFS) were calculated by STATA software 14.0 to assess the prognostic significance.

Results : Of the 56 included studies, there were 18 studies on CD56, 31 studies on CD57, 1 study on NKp30, and 7 studies on NKp46. High levels of CD56, CD57, NKp30, and NKp46 were significantly correlated with better OS of patients with solid malignancies (HR = 0.473, 95%CI: 0.315–0.710, p < 0.001; HR = 0.484, 95%CI: 0.380–0.616, p < 0.001; HR = 0.34, 95%CI: 0.14–0.80, p = 0.014; HR = 0.622, 95%CI: 0.470–0.821, p < 0.001, respectively). Our results also revealed that CD56, CD57, and NKp46 could act as independent prognostic predictors for favorable OS (HR = 0.372, 95%CI: 0.261–0.531, p < 0.001; HR = 0.525, 95%CI: 0.346–0.797, p = 0.003; HR = 0.559, 95%CI: 0.385–0.812, p = 0.002, respectively).

Conclusions : Our results indicated that high levels of NK cell markers in solid tumor tissues could predict favorable prognosis for solid tumor patients.

Interleukin-37 suppresses hepatocellular carcinoma growth through inhibiting M2 polarization of tumor-associated macrophages

Interleukin (IL)-37 has anti-tumor effects in hepatocellular carcinoma (HCC). Evidence shows that tumor-associated macrophages (TAMs) promote tumor progression. This study was designed to investigate the functional role of IL-37-mediated polarization of TAMs in HCC progression. HCC patient-derived TAMs were transfected with lentiviruses expressing IL-37 (LV-IL-37) and IL-37 siRNA and then the conditioned medium from TAMs were used to culture HCC cells (HepG2 and Huh-7). The phenotype of the macrophages was evaluated by detecting M1- or M2- type specific markers and cytokines. Cell proliferation, migration, and invasion were assessed. A tumor xenograft mouse model was generated with a subcutaneous injection of a mixture of HepG2 cells and TAMs/LV-IL-37. HCC patient-derived PBMCs showed M2 polarization and decreased IL-37 expression. Furthermore, IL-37 promoted TAMs polarization from M2 to M1 subtype through inhibiting the IL-6/STAT3 signaling. Moreover, IL-6 upregulation by recombinant human IL-6 (rhIL-6) blocked the IL-37 overexpression-mediated inhibition of HCC cell proliferation, migration, and invasion. In addition, IL-37 overexpression in HCC patient-derived TAMs inhibited tumor growth in vivo. Collectively, IL-37 suppresses HCC growth through inhibiting M2 polarization of TAMs via regulating the IL-6/STAT3 pathway.

Decreased IL-37 expression in hepatocellular carcinoma tissues and liver cancer cell lines

The role of IL-37 in cancer is currently largely unknown. The present study aimed to investigate IL-37 expression in hepatocellular carcinoma (HCC), paracancerous tissues (PT) and liver cancer cell lines, and their associations between IL-37 and NF-κB. A total of 65 HCC and 65 PT tissues were collected. The expression of IL-37 and NF-κB in tissues was detected by immunohistochemistry (IHC) and the data was analyzed using SPSS software. In the in vitro studies, IL-37 gene was transfected into HepG2 and MHCC97H cell lines with Lipofectamine 3000, and the protein regulation of NF-κB by IL-37 was verified by immunofluorescence (IF) and western blotting. In HCC, the positive expression rates of IL-37 and NF-kB were 21.5 and 95.4%, respectively. In PT, strong positive staining of IL-37and weak positive staining of NF-κB were observed. The normal expression levels of IL-37 and NF-κB, the increased IL-37 and decreased NF-κB induced by IL-37 gene transfection were observed through IF in cell lines. In terms of clinical significance, the difference in IL-37 expression between HCC and PT was statistically significant (χ²=55.05; P<0.001). IL-37 expression in HCC but not PT was negatively associated with serum AFP (χ²=6.522; P=0.039). IL-37 expression in PT was associated with sex (χ²=13.12; P=0.003) and tumor size (χ²=7.996; P=0.045). NF-κB expression in PT was associated with age, sex and BCLC stage. Notably, there was a negative correlation between IL-37 and NF-κB in HCC (r=-0.277; P=0.029) but not in PT (P>0.05). IL-37 overexpression downregulated the NF-κB protein by 56.50% in HepG2 cells (P<0.05) and 30.52% in MHCC97H cells (P<0.05). In conclusion, the expression of IL-37 in HCC and PT was specifically associated with serum AFP and tumor size, respectively. IL-37 expression was negatively correlated with NF-κB protein expression in HCC tissues and liver cancer cell lines.

IL-37/ STAT3/ HIF-1α negative feedback signaling drives gemcitabine resistance in pancreatic cancer

Human interleukin (IL)-37 is a member of the IL-1 family with potent anti-inflammatory and immunosuppressive properties. Previously, it has been reported that IL-37 suppresses tumor growth and progression. However, the roles of IL-37 in pancreatic cancer development and chemo-resistance remain unknown.

Methods: Immunohistochemistry was used to analyze the correlation between IL-37 expression and clinicopathological features of pancreatic ductal adenocarcinoma (PDAC). Western-blot and RT-PCR was used to verify the correlation between IL-37 and hypoxia-inducible factor (HIF)-1α. We performed chromatin immunoprecipitation and luciferase assays to validate HIF-1α suppression of IL-37 expression. Moreover, gain- and loss-of-function studies in vitro and in vivo were used to demonstrate the biological function of IL-37 on PDAC development and chemo-resistance.

Results: Our results showed that IL-37 expression was remarkably decreased in PDAC tissues when compared to adjacent normal pancreatic tissues. Reduced IL-37 expression in PDACs was associated with increased PDAC histological grade, tumor size, lymph node metastasis and vessel invasion. IL-37 low patients also have remarkably shorter relapse-free and overall survival. Importantly, IL-37 expression was positively correlated with Gemcitabine efficacy. Mechanistically, HIF-1α attenuated IL-37 transcription by binding to the hypoxia response elements (HREs) in IL-37 promoter. Conversely, IL-37 suppressed HIF-1α expression through STAT3 inhibition. Functionally, downregulation of IL-37 in PDAC cells promoted chemo-resistance, migration and progression in vivo and in vitro.

Conclusions: Collectively, our data uncovered IL-37/ STAT3/ HIF-1α negative feedback signaling drives Gemcitabine resistance in PDAC.

Systematic review of the roles of interleukins in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a primary liver cancer with high morbidity and mortality that is often accompanied by immune system disorders and local lymphocyte infiltration. Tumor-infiltrating lymphocytes, cancer cells, stromal cells, and the numerous cytokines they produce, such as chemokines, interferons, tumor necrosis factors, and interleukins, collectively constitute the tumor microenvironment. As a main type of immune effector, interleukin plays opposing roles in regulating tumor cell progression, adhesion, and migration according to its different subtypes. Many reports have concentrated on the roles that interleukins play in HCC, but understanding them systematically remains challenging. This study reviewed the current data to comprehensively summarize the relationships between HCC progression and human interleukin gene families.

The indirect antiangiogenic effect of IL-37 in the tumor microenvironment

IL-37, a newly identified IL-1 family cytokine, has been shown to play an important role in inflammatory diseases, autoimmune diseases, and carcinogenesis. IL-37 has been suggested to suppress tumoral angiogenesis, whereas some publications showed that IL-37 promoted angiogenesis through TGF-β signaling in both physiologic and pathologic conditions. Therefore, the function of IL-37 in tumoral angiogenesis is not clear and the underlying mechanism is not known. In this current study, we investigated the direct role of IL-37 on endothelial cells, as well as its indirect effect on angiogenesis through functioning on tumor cells both in vitro and in vivo. We found that IL-37 treatment directly promoted HUVEC migration and tubule formation, indicating IL-37 as a proangiogenic factor. Surprisingly, the supernatants from IL-37 overexpressing tumor cell line promoted HUVEC apoptosis and inhibited its migration and tubule formation. Furthermore, we demonstrated that IL-37 suppressed tumor angiogenesis in a murine orthotopic hepatocellular carcinoma model, suggesting its dominant antiangiogenesis role in vivo. Moreover, microarray and qPCR analysis demonstrated that IL-37 reduced the expressions of proangiogenic factors and increased the expressions of antiangiogenic factors by tumor cells. Matrix metalloproteinase (MMP)2 expression was significantly decreased by IL-37 in both cell lines and murine tumor models. MMP9 and vascular endothelial growth factor expressions were also reduced in murine tumors overexpressing IL-37, as well as in cell lines overexpressing IL-37 under hypoxic conditions. In conclusion, although IL-37 could exert direct proangiogenic effects on endothelial cells, it plays an antiangiogenic role via modulating proangiogenic and antiangiogenic factor expressions by tumor cells in the tumor microenvironment.

The mechanism of dysbiosis in alcoholic liver disease leading to liver cancer

Currently, alcoholic liver disease (ALD) is one of the most prevalent chronic liver diseases worldwide, representing one of the main etiologies of cirrhosis and hepatocellular carcinoma (HCC). Although we do not know the exact mechanisms by which only a selected group of patients with ALD progress to the final stage of HCC, the role of the gut microbiota within the progression to HCC has been intensively studied in recent years. To date, we know that alcohol-induced gut dysbiosis is an important feature of ALD with important repercussions on the severity of this disease. In essence, an increased metabolism of ethanol in the gut induced by an excessive alcohol consumption promotes gut dysfunction and bacterial overgrowth, setting a leaky gut. This causes the translocation of bacteria, endotoxins, and ethanol metabolites across the enterohepatic circulation reaching the liver, where the recognition of the pathogen-associated molecular patterns via specific Toll-like receptors of liver cells will induce the activation of the nuclear factor kappa-B pathway, which releases pro-inflammatory cytokines and chemokines. In addition, the mitogenic activity of hepatocytes will be promoted and cellular apoptosis will be inhibited, resulting in the development of HCC. In this context, it is not surprising that microbiota-regulating drugs have proven effectiveness in prolonging the overall survival of patients with HCC, making attractive the implementation of these drugs as co-adjuvant for HCC treatment.

Low expression of IL-37 protein is correlated with high Oct4 protein expression in hepatocellular carcinoma

OBJECTIVE

The function of IL-37 in cancer remains largely unclear. The present research was to probe the protein expression of IL-37 and Oct4 in hepatocellular carcinoma (HCC), para-cancerous tissues (PT) and cancer cell lines, and discuss their relationship.

METHODS

Forty-nine HCC specimens and forty-nine PT samples were collected for immunohistochemical staining of IL-37 and Oct4 protein. Then, the correlations among IL-37, Oct4 and the clinical indicators were analyzed. In further in vitro studies, IL-37 was over expressed in HepG2 and MHCC97H cancer cell lines by gene transfection using a lipo3000 kit. Finally, the protein expression of IL-37 and Oct4 was detected by immunofluorescence and western blot to verify the in vivo correlation between IL and 37 and Oct4.

RESULTS

In HCC, IL-37 protein expression was weakly positive with a positive rate of 12.2% while Oct4 expression was strongly positive with a positive rate of 91.8%. In PT, strong positive IL-37 (83.7%) and weakly positive Oct4 (91.8%) were shown. The increased IL-37 and decreased Oct4 induced by IL-37 gene transfection were observed through IF in cells. In terms of clinical significance, the difference of IL-37 expression between HCC and PT was statistically significant (χ² = 51.815, P = 3.2796 × 10^-11). IL-37 in tumor tissues was associated with serum AFP (χ² = 5.515, P = 0.048) and cirrhosis (χ² = 7.451, P = 0.014). IL-37 expression of PT was link to gender (χ² = 10.376, P = 0.013) and tumor size (χ² = 8.118, P = 0.04). The expression of Oct4 in HCC was related to the patient's gender and cirrhosis. Importantly, there was a negative correlation between IL and 37 and Oct4 in tumor tissues (r = -0.299, P = 0.047) but not in PT (P > 0.05). Oct4 protein expression was down-regulated by IL-37 by 63.35% in HepG2 cells (P < 0.05) and 95.20% in MHCC97H cells (P < 0.05).

CONCLUSION

IL-37 expression in tumor tissues and PT was related to serum AFP and liver cirrhosis, tumor size, respectively. IL-37 protein expression was correlated with Oct4 in cancer cell lines and tumor tissues but not PT. The present study indicated that IL-37 might play a role in the development of HCC.

Inhibition of human cervical cancer cell invasion by IL-37 involving runt related transcription factor 2 suppression

Background

IL-37 is a newly anti-inflammatory cytokine whose function is largely unknown in cancer. Our preliminary experiment found IL-37 could inhibit the invasion of human cervical cancer (CC) cells and influence the expression of RUNX family whose function was also unclear in CC. The present study aims to further investigate the effects of IL-37 on cell invasion and runt related transcription factor 2 (RUNX2) expression in CC cell lines.

Methods

Firstly, plasmid overexpressing IL-37 or RUNX2 was transfected into Siha and C33A cells by Hilymax. Then, the effects of IL-37 on the mRNA expression of RUNX1, RUNX2 and RUNX3 gene were detected by quantitative real-time polymerase chain reaction. Protein expression was measured by Western blot and the grayscale scanning analysis. Finally, the effects of IL-37 or RUNX2 on cell invasion were tested by transwell assay.

Results

IL-37 inhibited the mRNA expression of RUNX1 and RUNX2, and increased that of RUNX3 in CC cells. Among the three RUNX genes, RUNX2 showed the most significant change in mRNA expression (decreased by78.5% in Siha cells and by 61.5% in C33A cells) and thus was chosen for the following study. Overexpressed IL-37 inhibited cell invasion by 36.23% in Siha cells (P<0.05) and 26.21% in C33A cells (P<0.01). Overexpression of RUNX2 promoted cell invasion. Up-regulation of IL-37 suppressed markedly the mRNA and protein expression of RUNX2. Furthermore, overexpressed RUNX2 partially restored the inhibited cell invasion by IL-37 to 86.62% in Siha cells (P<0.01) and 87.08% in C33A cells (P<0.01).

Conclusions

IL-37 can significantly inhibit the cell invasion of Siha and C33A cells, which involves the suppression of RUNX2.

Interleukin-37 is highly expressed in regulatory T cells of melanoma patients and enhanced by melanoma cell secretome

Immune suppression is one of the 10 hallmarks of cancer. Interleukin-37 (IL-37), a member of the IL-1 family, inhibits both innate and adaptive immunity, and has been shown to modulate immune responses in various disease conditions. Yet, IL-37 has rarely been investigated in cancer patients, and its biological role in cancer remains to be elucidated. In this study, we investigated the gene expression of IL-37 in age- and sex-matched blood samples of healthy individuals and melanoma patients, and demonstrated upregulation of IL-37 messenger RNA (mRNA) in the blood samples of melanoma patients. By further analyzing immune cell subsets responsible for the upregulated IL-37 expression, we discovered that IL-37 mRNA was highly expressed in T cells and granulocytes, with the highest expression in regulatory T (Treg ) cells in healthy individuals, and that IL-37 mRNA was upregulated in lymphocytes (T, B, and natural killer cells) in melanoma patient blood. Among all cell subsets, Treg cells from melanoma patients exhibited the highest IL-37 gene expression levels. We provided evidence that melanoma-conditioned media induces IL-37 mRNA and protein expression in multiple lymphocyte populations, particularly in Treg cells. We further confirmed that the IL-1-mediated secretome from human melanoma cells, specifically transforming growth factor-β, induces IL-37 mRNA expression in human Treg cells. Our results suggest a potential immunosuppressive role for IL-1 and IL-37 in melanoma tumorigenesis. Highly elevated IL-37 in specific lymphocyte populations could serve as a biomarker for tumor-induced immunosuppression.

Interleukin-1 Family Cytokines: Keystones in Liver Inflammatory Diseases

The pyrogenic property being the first activity described, members of the interleukin-1 superfamily (IL-1α, IL-1β, IL-18, and the newest members: IL-33, IL-36, IL-37, and IL-38) are now known to be involved in several inflammatory diseases such as obesity, atherosclerosis, cancer, viral and parasite infections, and auto-inflammatory syndromes as well as liver diseases. Inflammation processes are keystones of chronic liver diseases, of which the etiology may be viral or toxic, as in alcoholic or non-alcoholic liver diseases. Inflammation is also at stake in acute liver failure involving massive necrosis, and in ischemia-reperfusion injury in the setting of liver transplantation. The role of the IL-1 superfamily of cytokines and receptors in liver diseases can be either protective or pro-inflammatory, depending on timing and the environment. Our review provides an overview of current understanding of the IL-1 family members in liver inflammation, highlighting recent key investigations, and therapeutic perspectives. We have tried to apply the concept of trained immunity to liver diseases, based on the role of the members of the IL-1 superfamily, first of all IL-1β but also IL-18 and IL-33, in modulating innate lymphoid immunity carried by natural killer cells, innate lymphoid cells or innate T-αβ lymphocytes.

IL-37 induces anti-tumor immunity by indirectly promoting dendritic cell recruitment and activation in hepatocellular carcinoma

Introduction

IL-37 is a cytokine of IL-1 family that plays an important role in innate immunity and inflammation, and has been studied as a tumor suppressor in many cancers. However, it remains unclear whether IL-37 plays a regulatory role in tumor-infiltrating dendritic cells (DCs) in hepatocellular carcinoma (HCC).

Materials and methods

We evaluated the relationship between IL-37 expression and tumor infiltration by DCs in 155 HCC samples through immunohistochemical analysis and Kaplan–Meier survival analysis. The effects of IL-37 on the anti-tumor activity of DCs were investigated by ELISA, flow cytometry, real-time quantitative PCR, cytotoxicity assays and tumorigenicity assays.

Results

The expression level of IL-37 in HCC samples was positively correlated with the degree of CD1a⁺ DCs infiltration. The survival rates of patients with both a high expression of IL-37 and a high infiltration by CD1a⁺ DCs were significantly higher than those of patients with a low expression of IL-37 and a low infiltration by CD1a⁺ DCs. In vitro chemotaxis analysis indicated that HCC cells overexpressing IL-37 recruited more DCs by secreting higher levels of specific chemokines (eg, CCL3 and CCL20). In addition, IL-37 indirectly up-regulated the expression of major histocompatibility class II molecules, CD86 and CD40 on DCs by acting on tumor cells; IL-37 also indirectly enhanced the anti-tumor effect of T lymphocytes by stimulating DCs to secrete cytokines such as IL-2, IL-12, IL-12p70, interferon-α (IFN-α) and IFN-γ. Finally, overexpression IL-37 in HCC cells significantly delayed tumor growth and increased recruitment of CD11c⁺ DCs to tumor tissues was also revealed in vivo mouse model.

Conclusion

DCs play an important role in IL-37 mediated anti-tumor immune responses in HCC, which may contribute to the development of novel cancer immunotherapeutic strategies.

IL-1 Family Members in Cancer; Two Sides to Every Story

The IL-1 family of cytokines currently comprises of seven ligands with pro-inflammatory activity (IL-1α and IL-1β, IL-18, IL-33, IL-36α, IL-36β, IL-36γ) as well as two ligands with anti-inflammatory activity (IL-37, IL-38). These cytokines are known to play a key role in modulating both the innate and adaptive immunes response, with dysregulation linked to a variety of autoimmune and inflammatory diseases. Given the increasing appreciation of the link between inflammation and cancer, the role of several members of this family in the pathogenesis of cancer has been extensively investigated. In this review, we highlight both the pro- and anti-tumorigenic effects identified for almost all members of this family, and explore potential underlying mechanisms accounting for these divergent effects. Such dual functions need to be carefully assessed when developing therapeutic intervention strategies targeting these cytokines in cancer.

Association between IL-37 gene polymorphisms and risk of HBV-related liver disease in a Saudi Arabian population

Interleukin-37 (IL-37) has recently been recognized as a strong anti-inflammatory cytokine having anti-tumor activity against hepatocellular carcinoma (HCC) in hepatitis B virus (HBV)-infected patients. HCC is a typical inflammation-related cancer, and genetic variations within the IL-37 gene may be associated with the risk of HBV infection. Identification of the allelic patterns that genetically have a high disease risk is essential for the development of preventive diagnostics for HBV-mediated liver disease pathogenesis. In this study, we aimed to investigate the association between single nucleotide polymorphisms (SNPs) within the IL-37 gene and disease sequelae associated with HBV infection. We genotyped ten IL-37 SNPs in 1274 patients infected with HBV and 599 healthy controls from a Saudi Arabian population. Among the selected SNPs, two SNPs (rs2723175 and rs2708973) were strongly associated with HBV infection, and six SNPs (rs2723176, rs2723175, rs2723186, rs364030, rs28947200, rs4392270) were associated with HBV clearance, comparing healthy controls and HBV infected-patients respectively. A suggestive association of rs4849133 was identified with active HBV surface antigen (HBsAg) carrier and HBV-related liver disease progression. In conclusion, our findings suggest that variations at the IL-37 gene may be useful as genetic predictive risk factors for HBV infection and HBV-mediated liver disease progression in the Saudi Arabian population.

IL-37 promotes cell apoptosis in cervical cancer involving Bim upregulation

Background: Growing evidence has indicated that interleukin-37 (IL-37) is a potential anticancer molecule that mainly plays an inhibiting role in different kinds of cancers, but data for the role of IL-37 on cell apoptosis in cancers remains rare. The present study aimed to explore the role of IL-37 in cell apoptosis in cervical cancer, and the involved apoptosis-related molecules.

Methods: IL-37 was overexpressed by transfecting the pIRES2-EGFP-IL-37 plasmid in HeLa and C33A cells. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was performed to detect the mRNA expression of IL-37, Bcl-2, Bax and Bim. Western blotting was performed to detect the protein expression of IL-37 and Bim. Cell apoptosis was detected by flow cytometry.

Results: IL-37 upregulated the mRNA expression levels of Bim by 138.40% for HeLa (P<0.05) and 58.95% for C33A (P<0.05), and increased the protein expression levels of BimL by 69.10% (P<0.05) and 56.66% (P<0.05) in HeLa and C33A, respectively. Overexpression of IL-37 increased the apoptosis rates by 152.86% for HeLa (P<0.01) and 25.4% for C33A (P<0.05). Knockdown of Bim by specific siRNA interference fragments (SiBim) reduced the apoptosis rates by 36.00% for HeLa (P<0.05) and 14.66% for C33A (P<0.05). Compared with the IL-37 overexpression group, the apoptosis rate in cotransfecting the IL-37 overexpression plasmid and SiBim group decreased by approximately 31% (P<0.05) and 24.35% (P<0.05) in HeLa and C33A, respectively.

Conclusion: IL-37 upregulated Bim in cervical cancer cells. Furthermore, IL-37 can promote cervical cancer cell apoptosis, but Bim knockdown decreased this promotion through IL-37. Thus, IL-37 can promote cervical cancer cell apoptosis, which involve the upregulation of Bim.