IL-37 mediates the antitumor activity in renal cell carcinoma

Modulating inflammation with interleukin 37 treatment ameliorates murine Autosomal Dominant Polycystic Kidney Disease

Autosomal Dominant Polycystic Kidney Disease (ADPKD) is a leading cause of kidney failure and is associated with substantial morbidity and mortality. Interstitial inflammation is attributed to the action of infiltrating macrophages and is a feature thought to aggravate disease progression. Here, we investigated the therapeutic potential of the anti-inflammatory IL37b cytokine as a treatment for ADPKD using genetic mouse models, demonstrating that transgenic expression of human IL37b reduced collecting duct cyst burden in both early and adult-onset ADPKD rodent models. Moreover, injection of recombinant human IL37b could also reduce cyst burden in early onset ADPKD mice, an observation not associated with increased macrophage number at early stages of cyst formation. Interestingly, transgenic IL37b expression also did not alter macrophage numbers in advanced disease. Whole kidney RNA-seq highlighted an IL37b-mediated upregulation of the interferon signaling pathway and single-cell RNA-seq established that these changes originate at least partly from kidney resident macrophages. We further found that blocking type I interferon signaling in mice expressing IL37b resulted in increased cyst number, confirming this as an important pathway by which IL37b exerts its beneficial effects. Thus, our studies show that IL37b promotes interferon signaling in kidney resident macrophages which suppresses cyst initiation, identifying this protein as a potential therapy for ADPKD.

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 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.

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.

Tanshinone IIA-regulation of IL-6 antagonizes PM2 .5 -induced proliferation of human bronchial epithelial cells via a STAT3/miR-21 reciprocal loop

Particulate matter 2.5 (PM_2.5 ), a component of atmospheric particulate matter, leads to changes in gene expression and cellular functions. Epidemiological evidence confirms that PM_2.5 has a positive correlation with lung injury. However, the molecular mechanisms involved remain poorly understood, and preventive methods are needed. In the present study, with human bronchial epithelial (HBE) cells in culture, we showed that low concentrations of PM_2.5 resulted in acceleration of the G1/S transition and cell proliferation. Consistent with these effects, expression of the pro-inflammatory factor interleukin-6 (IL-6) was elevated in HBE cells exposed to PM_2.5 . Accordingly, signal transducer and activator of transcription 3 (STAT3) was activated, which down-regulated expression of cyclin D1. In addition, PM_2.5 exposure led to higher levels of miR-21, and there was a reciprocal loop between miR-21 and STAT3. For HBE cells, tanshinone IIA (Tan IIA) reversed the PM_2.5 -induced cell cycle alteration and cell proliferation, and reduced the expression of cytokines (IL-6, STAT3, and miR-21). These results show that, for HBE cells, Tan IIA attenuates the PM_2.5 -induced G1/S alteration and cell proliferation, and indicate that it has potential clinical application for PM_2.5 -induced respiratory injuries.

Extracellular IL-37 promotes osteogenic and odontogenic differentiation of human dental pulp stem cells via autophagy

The osteogenic and odontogenic differentiation of dental pulp stem cells (DPSCs) contribute to restoration and regeneration of dental tissue. Previous study indicated that interleukin-37 (IL-37) was an anti-inflammatory factor that affected other pro-inflammatory signals. The aim of this study was to explore the effects of IL-37 on the differentiation of DPSCs. DPSCs were cultured in growth medium with different concentrations of IL-37. We selected the optimal concentration for the following experiments by alkaline phosphatase (ALP) activity analysis, quantitative reverse-transcription polymerase chain reaction (qRT-PCR) and Western blot. Cell counting kit assay (CCK-8) and 5-Ethynyl-2'-Deoxyuridine (EdU) assay were conducted to assess the effects of IL-37 on the proliferation of DPSCs. ALP activity assay and staining, alizarin red S (ARS) staining, qRT-PCR, Western blot as well as immunofluorescence staining were conducted to assess differentiation ability of DPSCs. Western blot, immunofluorescence staining and transmission electron microscopy (TEM) were utilized to examine cell autophagy. Results showed that IL-37 enhanced the osteogenic and odontogenic differentiation ability of DPSCs with no significant influence on the proliferation of DPSCs. Autophagy in DPSCs was activated by IL-37. Activation of autophagy enhanced osteogenesis and odontogenesis of DPSCs, whereas inhibition of autophagy suppressed DPSCs osteogenic and odontogenic differentiation. In conclusion, IL-37 increased osteogenic and odontogenic differentiation via autophagy.

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.

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.

IL-37 Exerts Anti-Inflammatory Effects in Fetal Membranes of Spontaneous Preterm Birth via the NF-κB and IL-6/STAT3 Signaling Pathway

Spontaneous preterm birth (sPTB), defined as delivery before 37 weeks of gestation, is thought to be a multifactorial syndrome. However, the inflammatory imbalance at the maternal-fetal interface promotes excessive secretion of inflammatory factors and induces apoptosis and degradation of the extracellular matrix (ECM), which can subsequently lead to preterm birth. As an anti-inflammatory molecule in the IL-1 family, interleukin-37 (IL-37) mainly plays an inhibiting role in a variety of inflammatory diseases. However, as a typical inflammatory disease, no previous studies have been carried out to explore the role of IL-37 in sPTB. In this study, a series of molecular biological experiments were performed in clinical samples and human amniotic epithelial cell line (Wistar Institute Susan Hayflick (WISH)) to investigate the deficiency role of IL-37 and the potential mechanism. Firstly, the results indicated that the expression of IL-37 in human peripheral plasma and fetal membranes was significantly decreased in the sPTB group. Afterward, it is proved that IL-37 could significantly suppress the production of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6) in WISH cells. Simultaneously, once silence IL-37, LPS-induced apoptosis and activity of matrix metalloproteinases (MMPs) 2 and 9 were significantly increased. In addition, the western blot data showed that IL-37 performed its biological effects by inhibiting the NF-κB and IL-6/STAT3 pathway. In conclusion, our results suggest that IL-37 limits excessive inflammation and subsequently inhibits ECM remodeling and apoptosis through the NF-κB and IL-6/STAT3 signaling pathway in the fetal membranes.

RETRACTED: Interleukin-36 receptor antagonist is associated with the progression of renal cell carcinoma

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal). This article has been retracted at the request of the Editor-in-Chief. This article has similarities to seven other papers that have been published. They have similar Kaplan-Meier curves, and tables and table values. These similar graphics and tables apply to different disease states, target mediators and numbers of patients in different studies. After the comments of Dr Elisabeth Bik https://pubpeer.com/publications/39A1613F4546DA16064BA441B29A0F regarding this article, the journal requested the author to provide the raw data. However, the author did not respond. Dr Elisabeth Bik is acknowledged for pointing out the irregularities in these papers.

Epigenetic reprogramming in periodontal disease: Dynamic crosstalk with potential impact in oncogenesis

Periodontitis is a chronic multifactorial inflammatory disease associated with microbial dysbiosis and characterized by progressive destruction of the periodontal tissues. Such chronic infectious inflammatory disease is recognized as a major public health problem worldwide with measurable impact in systemic health. It has become evident that the periodontal disease phenotypes are not only determined by the microbiome effect, but the extent of the tissue response is also driven by the host genome and epigenome patterns responding to various environmental exposures. More recently there is mounting evidence indicating that epigenetic reprogramming in response to combined intrinsic and environmental exposures, might be particularly relevant due its plasticity and potential application towards precision health. The complex epigenetic crosstalk is reflected in the prognosis and progress of periodontal diseases and may also lead to a favorable landscape for cancer development. This review discusses epigenomics modifications focusing on the role of DNA methylation and pathways linking microbial infection and inflammatory pathways, which are also associated with carcinogenesis. There is a more clear vision whereas 'omics' technologies applied to unveil relevant epigenetic factors could play a significant role in the treatment of periodontal disease in a personalized mode, evidencing that public health approach should coexist with precision individualized treatment.

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.

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 balance of serum IL-18/IL-37 levels is disrupted during the development of oral squamous cell carcinoma

Growing evidences have demonstrated a pivotal role of chronic inflammation in oral squamous cell carcinoma (OSCC) through the modulation of inflammatory cells and cytokine production. IL-37 is newly discovered anti-inflammatory member of IL-1 family and can bind to IL-18 receptor to inhibit IL-18 (pro-inflammatory member of IL-1 family) function. Investigation on the balance of IL-18/IL-37 would provide new insights into the function of IL-1 family in OSCC. Thus, serum IL-18 and IL-37 levels of OSCC patients (n = 108), leukoplakia patients (n = 40), and healthy donors (n = 36) were collected to analyze the balance of IL-18 and IL-37, and also determine their diagnostic value and prognostic significance in OSCC. The results showed that OSCC patients had high IL-18 and low IL-37 levels in serum and peripheral blood mononuclear cell (PBMC). The ratio of IL-18/IL-37 in serum efficiently distinguished non-cancer individuals from OSCC patients (cut off value: 2.15). Moreover, patients with high IL-18 and low IL-37 were susceptible to develop advanced tumor stage and lymph node metastasis (Odd ratios of IL-18/IL-37 is 4.903 and 12.613, respectively). Meanwhile, higher IL-18/IL-37 ratio could predict shorter overall survival and disease-free survival of OSCC patients, although it was not an independent prognostic factor. We further analyze the correlations of serum IL-18/IL-37 with immunocytes in peripheral blood and found that high IL-18 level was associated with more CD19⁺ B cells, while serum IL-37 seem to be associated with reduced percentage of CD3⁺CD8⁺ T cells, indicating its balance could change the adaptive immune response. Unexpectedly, we first revealed the different function of IL-18/IL-37 in serum and tumor tissues. High mRNA expression of IL-18 in tumor tissues correlated with low lymph node metastasis rate and low tumor stage, which was contradictory to the pro-tumor role of IL-18 in serum. In conclusion, enhanced ratio of IL-18/IL-37 level in serum could be an efficient biomarker for OSCC. Its balance might regulate CD19⁺ B cells and CD3⁺ CD8⁺ T cells for OSCC progression.

Vaccinia virus expressing IL-37 promotes antitumor immune responses in hepatocellular carcinoma

The aim of this study was to investigate the effect of vaccinia virus expressing IL-37 (VV-IL-37) on cell proliferation, migration and invasion of hepatocellular carcinoma (HCC) and its possible underlying molecular mechanisms. In this study, we constructed a cancer-targeted vaccinia virus carrying the IL-37 gene knocked in the region of the viral thymidine kinase (TK) gene. Human HCC cell lines were assayed in vitro for cell proliferation, migration and invasion. Serum level, relative mRNA level and protein level of IL-37 in HCC cell lines SMMC7721 and Bel7402 were tested by ELISA assay, qRT-PCR and western blot, respectively. The levels of IL-2, IFN-γ and TNF-α in HCC tumor tissues were also analyzed by ELISA. STAT3 and p-STAT3 expression in tumor tissues were determined by western blot. Our results showed that VV-IL-37 efficiently infected and inhibited HCC cells proliferation, migration and invasion via decreasing STAT3 phosphorylation. In vivo, VV-IL-37 expressed IL-37 at a high level in the transplanted tumor, reduced STAT3 activity, and eventually inhibited tumor growth. In conclusion, we demonstrate that VV-IL-37 promotes antitumor immune responses in HCC.

Interleukin-37 Inhibits Colon Carcinogensis During Chronic Colitis

Inflammatory bowel disease increases the risk of developing colon cancer. Interleukin (IL-) 37 is a fundamental inhibitor of innate immunity by reducing systemic and local inflammation. IL-37 protein is expressed in healthy and diseased bowel and liver tissue. Here, we tested whether transgenic expression of human IL-37 protects IL-10 deficient (IL-10KO) mice from chronic colitis. IL-37tg mice were crossbred with IL-10KO mice. Homozygous IL-10KO/IL-37tg and IL10KO drank 2% dextran sulfate sodium (DSS) in water for 5 days to induce mild colitis. Colon carcinogenesis was triggered by intragastric administration of celecoxib. Endpoints were clinical parameters of colitis, cytokine responses in LPS-stimulated whole blood and explanted colon specimen and qPCR analysis of colon biopsies. Colon inflammation and number of adenoma-carcinoma were analyzed by histology. During the DSS-induction phase IL-10KO and IL-10KO/IL-37tg mice had a similar weight loss due to mild acute colitis. From day 115 there was a significantly improved weight gain in IL-10KO/IL37-tg mice, though colon length was similar. After ex vivo LPS stimulation whole blood of IL-10KO/IL-37tg compared to IL-10KO mice released less IL-6, IL-17, IFNγ, and TNFα and ex vivo colon cultures showed reduced IL-6 production both indicative of reduced inflammatory conditions under the influence of IL-37. Six out of 10 IL-10KO mice developed colon adenoma and carcinoma. Only one adenoma but no carcinoma was detected in colons of IL-10KO/IL-37tg mice. In conclusion, IL-37 transgene expression protects IL-10KO mice from colon carcinogenesis. It remains unclear whether IL-37 has direct tumor suppressing properties.

Extracellular IL-37 promotes osteogenic differentiation of human bone marrow mesenchymal stem cells via activation of the PI3K/AKT signaling pathway

Interleukin (IL)-37, a pivotal anti-inflammatory cytokine and a fundamental inhibitor of innate immunity, has recently been shown to be abnormally expressed in several autoimmune-related orthopedic diseases, including rheumatoid arthritis, ankylosing spondylitis, and osteoporosis. However, the role of IL-37 during osteogenic differentiation of mesenchymal stem cells (MSCs) remains largely unknown. In this study, extracellular IL-37 significantly increased osteoblast-specific gene expression, the number of mineral deposits, and alkaline phosphatase activity of MSCs. Moreover, a signaling pathway was activated in the presence of IL-37. The enhanced osteogenic differentiation of MSCs due to supplementation of IL-37 was partially rescued by the presence of a PI3K/AKT signaling inhibitor. Using a rat calvarial bone defect model, IL-37 significantly improved bone healing. Collectively, these findings indicate that extracellular IL-37 enhanced osteogenesis of MSCs, at least in part by activation of the PI3K/AKT signaling pathway.

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.

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.

Knockdown of Delta-like 3 restricts lipopolysaccharide-induced inflammation, migration and invasion of A2058 melanoma cells via blocking Twist1-mediated epithelial-mesenchymal transition

AIMS

To investigate the effects and mechanisms of DLL3 in inflammation-mediated A2058 melanoma cell invasion and metastasis.

MATERIALS AND METHODS

Melanoma A2058 cells was stimulated with lipopolysaccharide (LPS), with or without transfection of DLL3 siRNA, or DLL3 overexpression vector, or Twist1 siRNA. Cell migration and invasion were detected by wound healing and transwell invasion assay. The production of inflammatory factors TNF-α and IL-6 was measured by ELISA. The expression of Notch signaling-related molecules was detected by PCR and western blot. The protein expression of MMP1, MMP9, VEGF, DLL3, and EMT-related molecules was tested by western blot.

KEY FINDINGS

LPS treatment increased migration and invasion of A2058 cells, accompanied by increased expression of TNF-α and IL-6. DLL3 was both upregulated in the LPS- or TNF-α-stimulated A2058 cells, and DLL3 knockdown inhibited LPS-induced inflammation, migration and invasion of A2058 cells, accompanied by down-regulation of MMP1, MMP9 and VEGF. Besides, DLL3 knockdown inhibits the expression of Twist1, a key EMT regulating factor, as well as the EMT hallmarks slug, N-cadherin and vimentin. Moreover, Twist1 silence inhibited EMT, and limited LPS-induced migration and invasion of A2058 cells, with decreased expression of MMP1, MMP9 and VEGF and reduced production of TNF-α and IL-6 in LPS-stimulated A2058 cells.

SIGNIFICANCE

Knockdown of DLL3 restricts LPS-induced inflammation, migration and invasion of A2058 melanoma cells via blocking Twist1-mediated EMT. Therefore, targeting DLL3 may be a promising therapeutic strategy against inflammation-aggravated melanoma progression.

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.

LncRNA ZEB2-AS1 contributes to the tumorigenesis of gastric cancer via activating the Wnt/β-catenin pathway

Studies have shown that long noncoding RNA Zinc finger E-box-binding homeobox 2 antisense RNA 1 (ZEB2-AS1) is involved in the progression of lung cancer, bladder cancer, and hepatocellular carcinoma. However, its role in the pathogenesis of gastric cancer remains unknown. The Wnt/β-catenin pathway contributes to the development of gastric cancer. ZEB2-AS1 expression was firstly detected in the gastric carcinoma tissue samples as well as in gastric cancer cells. Knockdown of ZEB2-AS1 was performed by ZEB2-AS1-shRNA, and the viability, migration, invasion, and apoptosis of gastric cancer cells were determined by CCK-8, scratch assay, transwell, and flow cytometry, respectively. Furthermore, levels of Ki-67, PCNA, VEGF, MMP9, epithelial-mesenchymal transition (EMT) markers (E-cadherin, Vimentin and ZEB2), cleaved caspase 3/8/9 and PARP, active β-catenin, c-Myc, cyclinD1, and AXIN2 were assayed by Western blot or real-time PCR. Additionally, the role and mechanism of ZEB2-AS1 were confirmed in a xenograft nude mouse model. We found ZEB2-AS1 expression was increased in gastric carcinoma samples, and it was correlated with tumor progression. Also, its expression was elevated in gastric cancer cells. Knockdown of ZEB2-AS1 reduced the proliferation, migration, invasion, and EMT, but increased the apoptosis of gastric carcinoma cells. Furthermore, ZEB2-AS1 downregulation remarkably suppressed the expression of Ki-67, PCNA, VEGF and MMP9, and the activation of Wnt/β-catenin signaling, whereas elevated the levels of cleaved caspase 3/8/9 and PARP in gastric cancer cells. And ZEB2 overexpression reversed the effects of ZEB2-AS1 downregulation on the proliferation, EMT and inactivation of Wnt/β-catenin signaling. Additionally, ZEB2-AS1 knockdown inhibited tumor growth, Ki-67 staining, and the expression of VEGF, MMP9, active β-catenin, c-Myc, cyclinD1, and AXIN2 in mice. In conclusion, ZEB2-AS1 promotes the tumorigenesis of gastric carcinoma that is related to the upregulation of ZEB2 and the activation of the Wnt/β-catenin pathway.

IL-37: An anti-inflammatory cytokine with antitumor functions

BACKGROUND

IL-37 is a newly identified IL-1 family cytokine. Unlike other members in IL-1 family, IL-37 has been demonstrated to be an anti-inflammatory cytokine in many inflammatory and autoimmune diseases. IL-37 is regarded as a dual-function cytokine as both the extracellular and intracellular IL-37 are biologically functional. Extracellular IL-37 can bind to IL-18Rα and IL-1R8 to form a triple complex, regulating the downstream STAT3 and PTEN signaling. Intracellular IL-37 can interact with Smad3, translocate into nucleus, and regulate downstream target gene expressions. Recently, the role of IL-37 in tumor development has been extensively studied.

RECENT FINDINGS

IL-37 has been found to play an antitumor role in various types of tumors, such as non-small cell lung cancer, hepatocellular carcinoma, and renal cell carcinoma. Many mechanism studies have been carried out to elaborate the possible effects of IL-37 on tumor growth, immune responses, and tumor angiogenesis. More importantly, the function of IL-37 may be dependent on its concentration and receptor expression. It can form dimers at high concentrations to be inactivated, thus inhibiting its anti-inflammatory function. We focused on the role of IL-37 in various tumor types and provided the hypothesis regarding the underlying mechanisms.

CONCLUSION

IL-37 may affect tumor development through multiple mechanisms: (1) IL-37 directly influences tumor cell viability; (2) IL-37 regulates the immune response to promote the antitumor immunity; and (3) IL-37 suppresses tumor angiogenesis in the tumor microenvironment. Future studies are warranted to further investigate the mechanisms of these multifaceted functions of IL-37 in animal models and cancer patients.

Effects of exogenous IL-37 on the biological characteristics of human lung adenocarcinoma A549 cells and the chemotaxis of regulatory T cells

BACKGROUND

This study aims to investigate the effects of exogenous interleukin (IL)-37 on the biological characteristics of human lung adenocarcinoma A549 cells and the chemotaxis of regulatory T (Treg) cells.

METHODS

After isolating the CD4+ CD25+ Treg cells from the peripheral blood, flow cytometry was used to detect the purity of the Treg cells. A549 cells were divided into blank (no transfection), empty plasmid (transfection with pIRES2-EGFP empty plasmid) or IL-37 group (transfection with pIRES2-EGFP-IL-37 plasmid). RT-PCR was used to detect mRNA expression of IL-37 and ELISA to determine IL-37 and MMP-9 expressions. Western blotting was applied to detect the protein expressions of PCNA, Ki-67, Cyclin D1, CDK4, cleaved caspase-3 and cleaved caspase-9. MTT assay, flow cytometry, scratch test and transwell assay were performed to detect cell proliferation, cycle, apoptosis, migration and invasion. Effect of exogenous IL-37 on the chemotaxis of Treg cells was measured through transwell assay. Xenograft models in nude mice were eastablished to detect the impact of IL-37 on A549 cells.

RESULTS

The IL-37 group had a higher IL-37 expression, cell apoptosis in the early stage and percentage of cells in the G0/G1 phase than the blank and empty plasmid groups. The IL-37 group had a lower MMP-9 expression, optical density (OD), percentage of cells in the S and G2/M phases, migration, invasion and chemotaxis of CD4+CD25+ Foxp3+ Treg cells. The xenograft volume and weight of nude mice in the IL-37 group were lower than those in the blank and empty plasmid groups. Compared with the blank and empty plasmid groups, the IL-37 group had significantly reduced expression of PCNA, Ki-67, Cyclin D1 and CDK4 but elevated expression of cleaved caspase-3 and cleaved caspase-9.

CONCLUSION

Therefore, exogenous IL-37 inhibits the proliferation, migration and invasion of human lung adenocarcinoma A549 cells as well as the chemotaxis of Treg cells while promoting the apoptosis of A549 cells.

Prognostic significance of nomograms integrating IL-37 expression, neutrophil level, and MMR status in patients with colorectal cancer

Interleukin (IL)‐37 and neutrophils are considered to be involved in human cancer, but their prognostic significance in colorectal cancer (CRC) has not been elucidated. The aim of this study was to evaluate the prognostic value of IL‐37 expression and neutrophil levels in CRC. We retrospectively analyzed IL‐37 expression, CD66b⁺ neutrophil levels, and mismatch repair (MMR) status in 337 paraffin‐embedded CRC specimens from the training cohort by immunohistochemistry. Their prognostic values were assessed using Kaplan‐Meier curves and multivariate Cox regression models. Moreover, several risk factors were used to form nomograms to evaluate survival, and the performance of the nomograms was assessed with respect to calibration, discrimination, and clinical usefulness. Further validation was performed in an independent cohort of 245 cases. Low IL‐37 expression and high CD66b⁺ neutrophil levels were significantly associated with diminished disease‐free survival (DFS) and overall survival (OS), and patients with MMR‐deficient CRC had better clinical outcomes. Furthermore, multivariate Cox analysis identified IL‐37, CD66b⁺ neutrophils, and MMR status as independent prognostic factors for DFS and OS. Two nomograms integrating the three markers with four clinicopathological risk factors were developed and validated for predicting DFS and OS with good calibration and discrimination (C‐index: training cohort, 0.798 (95% confidence interval:0.764‐0.832) and 0.828 (0.796‐0.860), respectively; validation cohort, 0.739 (0.696‐0.783) and 0.761 (0.715‐0.808), respectively). Decision curve analysis demonstrated that the nomograms were clinically useful. Intratumoral IL‐37, CD66b⁺ neutrophils, and MMR status were independent prognostic factors for CRC patients. Nomograms incorporating these biomarkers and clinicopathological features could be conveniently used to facilitate the individualized prediction of DFS and OS.

Interleukin-37 mediates the antitumor activity in colon cancer through β-catenin suppression

The occurrence and development of colon cancer is closely related to inflammation. Thus, we conducted the present retrospective study to investigate the effects of IL-37 (Interleukin 37), a newly identified anti-inflammatory factor, on colon cancer development. We first evaluated the IL-37 expression in 186 pairs of colon cancer samples and their adjacent normal mucosa by real-time PCR, ELISA (Enzyme-linked immunoassay) and tissue microarrays. Then the role of IL-37 on patient survival rates, colon cancer progression and their sensitivity to chemotherapy drugs were assessed. IL-37 was barely expressed in the colon cancer tissue but highly expressed in the adjacent normal tissue. The down-regulation of IL-37 was significantly correlated with the results of American Joint Committee on Cancer stage, nodal involvement, invasion depth, distant metastasis, differentiation and it was also shown to be an independent prognostic indicator of disease-free survival and overall survival for patients with colon cancer. Overexpression of IL-37 in colon cancer cell suppressed cell migration, invasion, proliferation, colony formation and cancer stem cells through suppressing β-catenin. IL-37 inhibited colon tumor formation in the mice model and sensitize the cancer cell to chemotherapy drugs. Our results showed that IL-37 plays an inhibitory role in colon cancer development and function as a novel prognostic indicator and a potential therapeutic target.

Reviews of Interleukin-37: Functions, Receptors, and Roles in Diseases

Interleukin-37 (IL-37) is an IL-1 family cytokine discovered in recent years and has 5 different isoforms. As an immunosuppressive factor, IL-37 can suppress excessive immune response. IL-37 plays a role in protecting the body against endotoxin shock, ischemia-reperfusion injury, autoimmune diseases, and cardiovascular diseases. In addition, IL-37 has a potential antitumor effect. IL-37 and its receptors may serve as novel targets for the study, diagnosis, and treatment of immune-related diseases and tumors.

IL-37 inhibits invasion and metastasis in non-small cell lung cancer by suppressing the IL-6/STAT3 signaling pathway

Background

IL‐37 has been identified as a fundamental inhibitor of inflammatory and immunity responses. It plays a crucial protective role in several cancers, but its anti‐tumor activity and the potential regulatory mechanism of IL‐37 in non‐small cell lung cancer (NSCLC) is largely unclear.

Methods

Enzyme‐linked immunosorbent assay was used to detect plasma IL‐37 expression in NSCLC patients and healthy controls. The NSCLC cell line A549 was cultured with recombinant human IL‐37 or recombinant human IL‐6 protein. A549 invasion and metastasis were detected using Transwell invasion and scratch wound healing assays, respectively. Protein expression of STAT3, pSTAT3, E‐cadherin, vimentin, and N‐cadherin were detected using Western blotting, and messenger RNA expression of STAT3, E‐cadherin, vimentin, and N‐cadherin was assessed in each group using real time PCR.

Results

IL‐37 plasma expression was decreased in NSCLC patients, and the downregulation of IL‐37 was correlated with tumor stage. In vitro, IL‐37 inhibited invasion and migration in A549 cells, while IL‐6 promoted invasion and migration in A549 cells. pSTAT3, vimentin, and N‐cadherin expression was increased. E‐cadherin expression was lower in the IL‐6 group than in the control group; however, the opposite pattern was observed in the IL‐37 + IL‐6 group.

Conclusion

Our results showed that IL‐37 plays an inhibitory role in NSCLC progression, possibly by suppressing STAT3 activation and decreasing epithelial‐to‐mesenchymal transition by inhibiting IL‐6 expression. IL‐37 could serve as a potential novel tumor suppressor in NSCLC.

IL-37 suppresses hepatocellular carcinoma growth by converting pSmad3 signaling from JNK/pSmad3L/c-Myc oncogenic signaling to pSmad3C/P21 tumor-suppressive signaling

IL-37 has been characterized as a fundamental inhibitor of innate immunity and a tumor suppressor in several cancers. However, the molecular mechanism of IL-37 in hepatocellular carcinoma (HCC) is largely unclear. In this study we found IL-37 expression was down-regulated in human HCC tissues and cell lines, and was negatively correlated with tumor size, vascular invasion, as well as overall-survial and disease-free survival (OS and DFS) of HCC. Multivariate Cox analysis revealed that IL-37 was an independent prognostic indicator for OS and DFS in HCC. Functional studies further showed that IL-37 overexpression significantly suppressed tumor growth by confining HCC to G2/M cell cycle arrest in vitro and in vivo. Mechanistically, we determined that IL-37 promoted Smad3 phospho-isoform signaling conversion from JNK/pSmad3L/c-Myc oncogenic signaling to pSmad3C/p21 tumor-suppressive signaling. Consistently, we detected a significant negative correlation between IL-37 expression and pSmad3L levels in a cohort of HCC biopsies; and the expression of pSmad3L predicted poorer outcome. These data highlight the importance of IL-37 in the cell proliferation and progression of HCC, and suggests that IL-37 may be a valuable biomarker for HCC prognosis.

The Low Expression of IL-37 Involved in Multiple Myeloma - Associated Angiogenesis

BACKGROUND Angiogenesis plays a significant role in complex inflammatory and angiogenic processes and is also involved in multiple myeloma (MM) pathogenesis. IL-37 is a proinflammatory cytokine in antitumor activity. Our purpose was to evaluate the IL-37 clinical significance on MM. MATERIAL AND METHODS We measured serum levels of IL-37 in 45 patients with different stages of MM and 30 healthy control subjects and correlated IL-37 with numerous cytokines, such as angiogenesis factors including vascular endothelial growth factor (VEGF) and angiotensin-2 (Ang-2). We also measured the tube formation of human umbilical vein endothelial cells (HUVECs) after pretreatment with recombinant human IL-37 (rhIL-37). RESULTS Serum IL-37 level was lower in the patients with MM than in the healthy control subjects, whereas VEGF and Ang-2 levels were higher, depending on International Staging System stage. Serum IL-37 level had a negative correlation to VEGF and Ang-2 levels, and VEGF had a positive correlation to Ang-2 level. The tube formation of HUVECs was suppressed by the rhIL-37 pretreatment. CONCLUSIONS Our results indicate that serum level of IL-37 plays a part in the pathophysiology of MM progression. Therefore, IL-37 serum level may be a biomarker for disease stage and angiogenesis processes.

IL-1 family cytokines in cancer immunity – a matter of life and death

IL-1 cytokines constitute a family of biologically active proteins with pleiotropic function especially in immunity. Both protective as well as deleterious properties of individual IL-1 family cytokines in tumor biology have been described. The function of IL-1-family cytokines depends on the producing source, the present (inflammatory) microenvironment and N-terminal proteolytical processing. Each of these determinants is shaped by different modes of cell death. Here we summarize the properties of IL-1 family cytokines in tumor biology, and how they are modulated by cell death.

The role of IL-37 in cancer

Interleukin 37 (IL-37) is a new member of the IL-1 family which all have a similar β-barrel structure. Since its discovery, IL-37 has been studied extensively in immunological field. It has been established that IL-37 possesses anti-inflammatory characteristics both in innate immune response as well as in acquired immune responses by downregulating pro-inflammatory molecules. This review will discuss the role of IL-37 in immunological processes and neoplastic pathogenesis.

Interleukin-37 expression and its potential role in oral leukoplakia and oral squamous cell carcinoma

Interleukin 37 (IL-37) has been reported to play a significant role in innate immune response and to be involved in several kinds of cancers. However, the investigation of association between IL-37 and oral mucosa carcinogenesis hasn't been clearly established. The aim of the study was to assess IL-37 expression and explore its role in oral mucosa carcinogenesis. The expression of IL-37 increased from normal control (NC) to Oral leukoplakia (OLK) and oral squamous cell carcinoma (OSCC). Moreover, statistically highly significant difference was present between scores of OLK with and without mild/moderate dysplasia (P < 0.001). In addition, IL-37 expression was lower in OSCC with lymph node metastasis than those without metastasis (P < 0.01). What's more, overexpression of IL-37 in RAW264.7 cells remarkably reduced the pseudopodia, vacuolization and the expression of IL-6, TNF-α, and IL-1β. Finally, we found IL-37 and its receptor IL-18Rα but not its binding partner IL-18BP have similar tissue location and expression trend in different stages of oral mucosa carcinogenesis. Overall, IL-37 can be used as a biomarker for early oral tumorigenesis and for malignant transformation risk assessment of premalignant lesions.