Significance of interleukin-33 and its related cytokines in patients with breast cancers

Pregnancy Reduces Il33+ Hybrid Progenitor Accumulation in the Aged Mammary Gland

Aging increases breast cancer risk while an early first pregnancy reduces a woman's life-long risk. Several studies have explored the effect of either aging or pregnancy on mammary epithelial cells (MECs), but the combined effect of both remains unclear. Here, we interrogate the functional and transcriptomic changes at single cell resolution in the mammary gland of aged nulliparous and parous mice to discover that pregnancy normalizes age-related imbalances in lineage composition, while also inducing a differentiated cell state. Importantly, we uncover a minority population of Il33 -expressing hybrid MECs with high cellular potency that accumulate in aged nulliparous mice but is significantly reduced in aged parous mice. Functionally, IL33 treatment of basal, but not luminal, epithelial cells from young mice phenocopies aged nulliparous MECs and promotes formation of organoids with Trp53 knockdown. Collectively, our study demonstrates that pregnancy blocks the age-associated loss of lineage integrity in the basal layer through a decrease in Il33+ hybrid MECs, potentially contributing to pregnancy-induced breast cancer protection.

The effect of interleukin-33 expression on prognosis in patients with nasopharyngeal carcinoma

INTRODUCTION

Interleukin-33 (IL-33) is a newly defined inflammatory cytokine that is a member of the interleukin-1 (IL-1) gene family. This cytokine is expressed in structural cells, such as the vascular endothelium, bronchial epithelial cells, keratinocytes, epithelial cells of the stomach, and fibroblastic reticular cells of lymphoid tissues. Several studies suggest that IL-33 plays a role in head-and-neck cancer. The aim of this study was to retrospectively examine IL-33 expression in nasopharyngeal carcinoma (NPC) and to evaluate its relationship between clinicopathological characteristics and prognosis.

METHODS

In this monocentric, retrospective analysis, the data of 43 cases diagnosed with primary NPC and 20 cases with normal nasopharyngeal tissue (diagnosed between 2014 and 2020) were evaluated regarding the relationship between the immunohistochemically analyzed IL-33 expression status and corresponding clinicopathological parameters.

RESULTS

The mean age was 56.9 years. The majority (67.4%) of the patients had an early tumor stage (T1-T2). IL-33 expression was positive in 56% of the cases. The five-year overall survival rate was 77% for all patients, 90% for the patients with positive IL-33 expression, and 55% for those without IL-33 expression (p = 0.008, univariate analysis). In multivariate analysis, IL-33 expression was shown to be the only independent prognostic marker for nasopharyngeal carcinoma (p = 0.014).

CONCLUSION

This retrospective study showed that IL-33 expression could be considered an independent factor affecting positively prognosis in NPC.

Interleukin-33 Expression on Treatment Outcomes and Prognosis in Brazilian Breast Cancer Patients Undergoing Neoadjuvant Chemotherapy

Interleukin-33 (IL-33), a member of the interleukin-1(IL-1) family of cytokines, remains poorly understood in the context of human breast cancer and its impact on treatment outcomes. This study aimed to elucidate IL-33 expression patterns within tumor samples from a cohort of Brazilian female breast cancer patients undergoing neoadjuvant chemotherapy while exploring its correlation with clinicopathological markers. In total, 68 samples were meticulously evaluated, with IL-33 expression quantified through a quantitative polymerase chain reaction. The findings revealed a substantial upregulation of IL-33 expression in breast cancer patient samples, specifically within the Triple-negative and Luminal A and B subtypes, when compared to controls (healthy breast tissues). Notably, the Luminal B subtype displayed a marked elevation in IL-33 expression relative to the Luminal A subtype (p < 0.05). Moreover, a progressive surge in IL-33 expression was discerned among Luminal subtype patients with TNM 4 staging criteria, further underscoring its significance (p < 0.005). Furthermore, chemotherapy-naïve patients of Luminal A and B subtypes exhibited heightened IL-33 expression (p < 0.05). Collectively, our findings propose that chemotherapy could potentially mitigate tumor aggressiveness by suppressing IL-33 expression in breast cancer, thus warranting consideration as a prognostic marker for gauging chemotherapy response and predicting disease progression in Luminal subtype patients. This study not only sheds light on the intricate roles of IL-33 in breast cancer but also offers valuable insights for future IL-33-related research endeavors within this context.

Decoding the IL-33/ST2 Axis: Its Impact on the Immune Landscape of Breast Cancer

Interleukin-33 (IL-33) has emerged as a critical cytokine in the regulation of the immune system, showing a pivotal role in the pathogenesis of various diseases including cancer. This review emphasizes the role of the IL-33/ST2 axis in breast cancer biology, its contribution to cancer progression and metastasis, its influence on the tumor microenvironment and cancer metabolism, and its potential as a therapeutic target. The IL-33/ST2 axis has been shown to have extensive pro-tumorigenic features in breast cancer, starting from tumor tissue proliferation and differentiation to modulating both cancer cells and anti-tumor immune response. It has also been linked to the resistance of cancer cells to conventional therapeutics. However, the role of IL-33 in cancer therapy remains controversial due to the conflicting effects of IL-33 in tumorigenesis and anti-tumor response. The possibility of targeting the IL-33/ST2 axis in tumor immunotherapy, or as an adjuvant in immune checkpoint blockade therapy, is discussed.

Plasma IL-33 levels and immune activation in HIV-TB coinfection: a cross-sectional study in Yaoundé, Cameroon

Introduction

HIV-1 and Mtb are characterized by immune activation and unbalances production of cytokines, but the expression of IL33 in HIV/TB coinfection remain understudied. This study aimed to evaluate the level of IL-33 in plasma of HIV and M. tuberculosis (HIV/TB) coinfected patients compared to patients with respective mono infections in Yaoundé.

Methods

a cross-sectional study was conducted among patients attending the pneumology service and HIV treatment center of the Yaoundé Jamot Hospital. Plasma samples of 157 HIV/TB coinfected patients (n =26, 50% males and 50% females, mean age 39), HIV-1 monoinfected patients (n = 41, 41% males and 59% females, mean age 35), TB monoinfected patients (n = 48, 56% males and 44% females, mean age 37) and healthy controls (n = 42, 29% males and 71% females, mean age 32) were examined by enzyme-linked immunoassay (ELISA) to detect the levels of IL-33 cytokine.

Results

plasma level of IL-33 were higher in HIV/TB coinfected (33.1±30.9 pg/ml) and TB monoinfected individuals (15.1±2.9 pg/ml) compared to healthy controls (14.0±3.4 pg/ml) and could not be detected in most of the HIV-1 monoinfected individuals (12.6±8.7 pg/ml). Interestingly, the increased plasma level of IL-33 in HIV/TB coinfected patients showed a statistically significant difference between healthy controls (33.1±30.9 pg/ml vs 14.0±3.4 pg/ml, P<0.0001) and HIV-1 monoinfected patients (33.1±30.9 pg/ml vs 12.6±8.7 pg/ml, P=0.0002). We further found that IL-33 was higher in patients with high viral load group (40.6±59.7 pg/ml vs 12.6±1.8 pg/ml), P= 0.47) whereas patients under highly active antiretroviral therapy (HAART) showed decreased level of IL-33 concentration as the number of years under ART increased. Our data showed a positive association between plasma IL-33 and viral load in the context of HIV/TB coinfection in our study population with a positive Pearson coefficient of r=0.21.

Conclusion

this study indicates that plasma level of IL-33 differs among HIV/TB coinfected patients and respective monoinfections patients. The increased level of plasma IL-33 reveals that IL-33 measurement in HIV-1 monoinfected patients may represent an early predictor of development of tuberculosis.

An exploration of the correlations between seven psychiatric disorders and the risks of breast cancer, breast benign tumors and breast inflammatory diseases: Mendelian randomization analyses

Background

Previous observational studies have showed that certain psychiatric disorders may be linked to breast cancer risk, there is, however, little understanding of relationships between mental disorders and a variety of breast diseases. This study aims to investigate if mental disorders influence the risks of overall breast cancer, the two subtypes of breast cancer (ER+ and ER-), breast benign tumors and breast inflammatory diseases.

Methods

During our research, genome-wide association study (GWAS) data for seven psychiatric disorders (schizophrenia, major depressive disorder, bipolar disorder, post-traumatic stress disorder, panic disorder, obsessive-compulsive disorder and anorexia nervosa) from the Psychiatric Genomics Consortium (PGC) and the UK Biobank were selected, and single-nucleotide polymorphisms (SNPs) significantly linked to these mental disorders were identified as instrumental variables. GWAS data for breast diseases came from the Breast Cancer Association Consortium (BCAC) as well as the FinnGen consortium. We performed two-sample Mendelian randomization (MR) analyses and multivariable MR analyses to assess these SNPs' effects on various breast diseases. Both heterogeneity and pleiotropy were evaluated by sensitivity analyses.

Results

When the GWAS data of psychiatric disorders were derived from the PGC, our research found that schizophrenia significantly increased the risks of overall breast cancer (two-sample MR: OR 1.05, 95%CI [1.03-1.07], p = 3.84 × 10^-6; multivariable MR: OR 1.06, 95%CI [1.04-1.09], p = 2.34 × 10^-6), ER+ (OR 1.05, 95%CI [1.02-1.07], p = 5.94 × 10^-5) and ER- (two-sample MR: OR 1.04, 95%CI [1.01-1.07], p = 0.006; multivariable MR: OR 1.06, 95%CI [1.02-1.10], p = 0.001) breast cancer. Nevertheless, major depressive disorder only showed significant positive association with overall breast cancer (OR 1.12, 95%CI [1.04-1.20], p = 0.003) according to the two-sample MR analysis, but not in the multivariable MR analysis. In regards to the remainder of the mental illnesses and breast diseases, there were no significant correlations. While as for the data from the UK Biobank, schizophrenia did not significantly increase the risk of breast cancer.

Conclusions

The correlation between schizophrenia and breast cancer found in this study may be false positive results caused by underlying horizontal pleiotropy, rather than a true cause-and-effect relationship. More prospective studies are still needed to be carried out to determine the definitive links between mental illnesses and breast diseases.

Hypoxia induces downregulation of the tumor-suppressive sST2 in colorectal cancer cells via the HIF-nuclear IL-33-GATA3 pathway

As a decoy receptor, soluble ST2 (sST2) interferes with the function of the inflammatory cytokine interleukin (IL)-33. Decreased sST2 expression in colorectal cancer (CRC) cells promotes tumor growth via IL-33-mediated bioprocesses in the tumor microenvironment. In this study, we discovered that hypoxia reduced sST2 expression in CRC cells and explored the associated molecular mechanisms, including the expression of key regulators of ST2 gene transcription in hypoxic CRC cells. In addition, the effect of the recovery of sST2 expression in hypoxic tumor regions on malignant progression was investigated using mouse CRC cells engineered to express sST2 in response to hypoxia. Our results indicated that hypoxia-dependent increases in nuclear IL-33 interfered with the transactivation activity of GATA3 for ST2 gene transcription. Most importantly, hypoxia-responsive sST2 restoration in hypoxic tumor regions corrected the inflammatory microenvironment and suppressed tumor growth and lung metastasis. These results indicate that strategies targeting sST2 in hypoxic tumor regions could be effective for treating malignant CRC.

Knowledge mapping of interleukin-33: a bibliometric study

Interleukin-33 (IL-33) is a member of the IL-1 family of cytokines. IL-33 is associated with the expression of tissue damage or necrosis after increasing and being released into the cell, it influences the suppression of tumorigenicity 2 (ST2) receptor expression of a variety of immune cells (including mast cells and type 2 congenital lymphocytes). Furthermore, during type 2 innate immune reactions and allergic inflammation IL-33 plays a central role in immune amplification and "alarming"; thus, regulating immune responeses. IL-33 is closely related to inflammation-related diseases such as allergic diseases, autoimmune diseases, infectious diseases, and tumors. It is essential in maintaining tissue homeostasis, eliminating inflammation, and repairing tissue damage. We searched the Web of Science Core Collection (WoSCC) database for relevant publications on IL-33 from 2005 to 2021 and screened them according to specific inclusion criteria. A total of 2626 articles were included in our analysis. Using Microsoft Excel 2019 (Redmond, WA), VOSviewer 1.6.11 (The Centre for Science and Technology Studies, CWTS), and Citespace5.8. R2 (Drexel University, Philadelphia, PA) were used for data processing and visualization. Countries/regions, journals, authors, co-cited references, and keywords were analyzed. We discovered that IL-33 plays an important role as a cytokine in numerous diseases, especially allergic diseases. Studying its mechanism of action is of great importance for developing novel drugs and therapeutics.

Knowledge mapping and research trends of IL-33 from 2004 to 2022: a bibliometric analysis

Background

IL-33 has been studied widely but its comprehensive and systematic bibliometric analysis is yet available. The present study is to summarize the research progress of IL-33 through bibliometric analysis.

Methods

The publications related to IL-33 were identified and selected from the Web of Science Core Collection (WoSCC) database on 7 December 2022. The downloaded data was analyzed with bibliometric package in R software. CiteSpace and VOSviewer were used to conduct IL-33 bibliometric and knowledge mapping analysis.

Results

From 1 January 2004 to 7 December 2022, 4711 articles on IL-33 research published in 1009 academic journals by 24652 authors in 483 institutions from 89 countries were identified. The number of articles had grown steadily over this period. The United States of America(USA) and China are the major contributors in the field of research while University of Tokyo and University of Glasgow are the most active institutions. The most prolific journal is Frontiers in Immunology, while the Journal of Immunity is the top 1 co-cited journal. Andrew N. J. Mckenzie published the most significant number of articles and Jochen Schmitz was co-cited most. The major fields of these publications are immunology, cell biology, and biochemistry & molecular biology. After analysis, the high-frequency keywords of IL-33 research related to molecular biology (sST2, IL-1), immunological effects (type 2 immunity, Th2 cells), and diseases (asthma, cancer, cardiovascular diseases). Among these, the involvement of IL-33 in the regulation of type 2 inflammation has strong research potential and is a current research hotspot.

Conclusion

The present study quantifies and identifies the current research status and trends of IL-33 using bibliometric and knowledge mapping analysis. This study may offer the direction of IL-33-related research for scholars.

Interleukin-33 and Soluble ST2 as Potential Biomarkers of Cancer in Opium Users: A Nested Case-Control Study

BACKGROUND

Opium abuse is one of the social hazards in the Middle Eastern countries. Opium consumption attributes to various malignancies. However, the exact molecular mechanism of this correlation still remains unclear. Cancer and inflammation are closely correlated. Interleukin-33 (IL-33) and its receptors, transmembrane ST2 (ST2L) and soluble ST2 (sST2), have been significantly associated with tumorigenicity. The present study aimed to investigate whether IL-33 and sST2 levels serve as cancer biomarkers in opium users.

METHODS

Serum samples were collected from 100 opium users and 100 healthy non-opium users in a nested case-control design. The subjects with over five years of history of opium abuse were enrolled. To assess the incidence of malignancies, the opium users were followed up from 2014 to 2019. Serum levels of IL-33 and sST2 were measured using an ELISA kit. For comparison of IL-33 and sST2 levels between the groups, two-tailed Student's t test and Mann-Whitney U test were utilized, accordingly. Logistic regression analysis was performed to evaluate the influence of confounders on the incidence of cancer.

RESULTS

During the five-year follow-up, eight opium users were diagnosed with cancer. Cancer was developed by 9.3 folds in the individuals abusing opium compared to that in the non-opium users (P=0.040, OR=9.3; 95%CI [1.1-79.4]). Serum levels of IL-33 were found to be significantly higher in the opium users than those in the healthy control group (P=0.001). The sST2 levels were significantly lower in the opium users (P=0.001). The opium users with cancer exhibited significantly higher levels of IL-33 and lower levels of sST2 than the cancer-free ones (P=0.001).

CONCLUSION

Decline in sST2 levels and rise in the level of IL-33 are valuable biomarkers in predicting cancers. Regarding the significant alterations in the levels of these biomarkers in the opium users, as well as those in the opium users diagnosed with cancer, IL-33 and sST2 may serve as potential biomarkers in the early prediction of cancer.

IL-33 biology in cancer: An update and future perspectives

Interleukin-33 (IL-33) is a member of the IL-1 family of cytokines that is constitutively expressed in the nucleus of epithelial, endothelial and fibroblast-like cells. Upon cell stress, damage or necrosis, IL-33 is released into the cytoplasm to exert its prime role as an alarmin by binding to its specific receptor moiety, ST2. IL-33 exhibits pleiotropic function in inflammatory diseases and particularly in cancer. IL-33 may play a dual role as both a pro-tumorigenic and anti-tumorigenic cytokine, dependent on tumor and cellular context, expression levels, bioactivity and the nature of the inflammatory environment. In this review, we discuss the differential contribution of IL-33 to malignant or inflammatory conditions, its multifaceted effects on the tumor microenvironment, while providing possible explanations for the discrepant findings described in the literature. Additionally, we examine the emerging and divergent functions of IL-33 in the nucleus, and aspects of IL-33 biology that are currently under-addressed.

IL-33 promotes gastric tumour growth in concert with activation and recruitment of inflammatory myeloid cells

Interleukin-33 (IL-33) is an IL-1 family cytokine known to promote T-helper (Th) type 2 immune responses that are often deregulated in gastric cancer (GC). IL-33 is overexpressed in human gastric tumours suggesting a role in driving GC progression although a causal link has not been proven. Here, we investigated the impact of IL-33 genetic deficiency in the well-characterized gp130^F/F mouse model of GC. Expression of IL-33 (and it’s cognate receptor, ST2) was increased in human and mouse GC progression. IL-33 deficient gp130^F/F/Il33^−/− mice had reduced gastric tumour growth and reduced recruitment of pro-tumorigenic myeloid cells including key mast cell subsets and type-2 (M2) macrophages. Cell sorting of gastric tumours revealed that IL-33 chiefly localized to gastric (tumour) epithelial cells and was absent from tumour-infiltrating immune cells (except modest IL-33 enrichment within CD11b⁺ CX3CR1⁺CD64⁺MHCII⁺ macrophages). By contrast, ST2 was absent from gastric epithelial cells and localized exclusively within the (non-macrophage) immune cell fraction together with mast cell markers, Mcpt1 and Mcpt2. Collectively, we show that IL-33 is required for gastric tumour growth and provide evidence of a likely mechanism by which gastric epithelial-derived IL-33 drives mobilization of tumour-promoting inflammatory myeloid cells.

Selenium nanoparticles and quercetin suppress thioacetamide-induced hepatocellular carcinoma in rats: Attenuation of inflammation involvement

The current study investigates the anti-inflammatory and hepatoprotective effects of selenium (Se) formulated as nanoparticles (SeNPs) and in combination with quercetin (QCT) against thioacetamide (TAA)-induced hepatocellular carcinoma (HCC) in rats. ​​​​​​Seventy-two male Sprague-Dawley rats were divided into six groups (n = 12). Three control groups; normal, SeNPs; group received SeNPs only and HCC; group received TAA. In addition, three preventive groups; SeNPs + TAA, QCT + TAA, and QCT + SeNPs + TAA. Induction of HCC was detected histopathologically and by the raise of the serum level of alpha-fetoprotein (AFP). Oxidative stress was evaluated by the hepatic levels of reduced glutathione (GSH), glutathione peroxidase (GPx), and malondialdehyde (MDA) spectrophotometrically. The oncogenic pathway of p53/β-catenin/cyclin D1 was assessed by immunohistochemistry. The inflammatory markers; interleukin-33 (IL-33), IL-6, and IL-1β were assessed by enzyme-linked immune sorbent assay. SeNPs prevented the elevation of serum AFP and hepatic IL-33, IL-1β, and IL-6 in comparison to HCC or QCT + TAA groups. SeNPs + TAA exhibited a lower positive hepatic staining of p53, β-catenin, and cyclin D1 in comparison to HCC or QCT + TAA groups. Moreover, SeNPs improved the overall oxidative balance indicated by low hepatic MDA and enhanced GSH and GPx when compared to HCC or QCT + TAA groups. ​​SeNPs alone and in combination with QCT were found to suppress the progression of HCC in rats via the enhancement of the oxidative stress and then inflammatory status and the prevention of the deregulation of the oncogenic axis pathway of p53/β-catenin/cyclin D.

Breast cancer in schizophrenia could be interleukin-33-mediated

Recent epidemiological and genetic studies have revealed an interconnection between schizophrenia and breast cancer. The mutual underlying pathophysiological mechanisms may be immunologically driven. A new cluster of molecules called alarmins may be involved in sterile brain inflammation, and we have already reported the potential impact of interleukin-33 (IL-33) on positive symptoms onset and the role of its soluble trans-membranes full length receptor (sST2) on amelioration of negative symptoms in schizophrenia genesis. Furthermore, these molecules have already been shown to be involved in breast cancer etiopathogenesis. In this review article, we aim to describe the IL-33/suppressor of tumorigenicity 2 (ST2) axis as a crossroad in schizophrenia-breast cancer comorbidity. Considering that raloxifene could be tissue-specific and improve cognition and that tamoxifen resistance in breast carcinoma could be improved by strategies targeting IL-33, these selective estrogen receptor modulators could be useful in complementary treatment. These observations could guide further somatic, as well as psychiatric therapeutical protocols by incorporating what is known about immunity in schizophrenia.

Proteomic Research on the Antitumor Properties of Medicinal Mushrooms

Medicinal mushrooms are increasingly being recognized as an important therapeutic modality in complementary oncology. Until now, more than 800 mushroom species have been known to possess significant pharmacological properties, of which antitumor and immunomodulatory properties have been the most researched. Besides a number of medicinal mushroom preparations being used as dietary supplements and nutraceuticals, several isolates from mushrooms have been used as official antitumor drugs in clinical settings for several decades. Various proteomic approaches allow for the identification of a large number of differentially regulated proteins serendipitously, thereby providing an important platform for a discovery of new potential therapeutic targets and approaches as well as biomarkers of malignant disease. This review is focused on the current state of proteomic research into antitumor mechanisms of some of the most researched medicinal mushroom species, including Phellinus linteus, Ganoderma lucidum, Auricularia auricula, Agrocybe aegerita, Grifola frondosa, and Lentinus edodes, as whole body extracts or various isolates, as well as of complex extract mixtures.

The Janus Face of IL-33 Signaling in Tumor Development and Immune Escape

Simple Summary

Interleukin-33 (IL-33) is often released from damaged cells, acting as a danger signal. IL-33 exerts its function by interacting with its receptor suppression of tumorigenicity 2 (ST2) that is constitutively expressed on most immune cells. Therefore, IL-33/ST2 signaling can modulate immune responses to participate actively in a variety of pathological conditions, such as cancer. Like a two-faced Janus, which faces opposite directions, IL-33/ST2 signaling may play contradictory roles on its impact on cancer progression through both immune and nonimmune cellular components. Accumulating evidence demonstrates both pro- and anti-tumorigenic properties of IL-33, depending on the complex nature of different tumor immune microenvironments. We summarize and discuss the most recent studies on the contradictory effects of IL-33 on cancer progression and treatment, with a goal to better understanding the various ways for IL-33 as a therapeutic target.

Abstract

Interleukin-33 (IL-33), a member of the IL-1 cytokine family, plays a critical role in maintaining tissue homeostasis as well as pathological conditions, such as allergy, infectious disease, and cancer, by promoting type 1 and 2 immune responses. Through its specific receptor ST2, IL-33 exerts multifaceted functions through the activation of diverse intracellular signaling pathways. ST2 is expressed in different types of immune cells, including Th2 cells, Th1 cells, CD8⁺ T cells, regulatory T cells (T_reg), cytotoxic NK cells, group 2 innate lymphoid cells (ILC2s), and myeloid cells. During cancer initiation and progression, the aberrant regulation of the IL-33/ST2 axis in the tumor microenvironment (TME) extrinsically and intrinsically mediates immune editing via modulation of both innate and adaptive immune cell components. The summarized results in this review suggest that IL-33 exerts dual-functioning, pro- as well as anti-tumorigenic effects depending on the tumor type, expression levels, cellular context, and cytokine milieu. A better understanding of the distinct roles of IL-33 in epithelial, stromal, and immune cell compartments will benefit the development of a targeting strategy for this IL-33/ST2 axis for cancer immunotherapy.

Plasma IL-33 levels are decreased in patients with high-risk myelodysplastic syndrome and show no correlation with pro-inflammatory IL-6 levels

Aberrant inflammatory signaling has been shown to be a key pathogenic driver in myelodysplastic syndromes (MDS). Abnormal IL-33 expression has been implicated in inflammatory, immune-related disorders and, some tumors. However, its role in MDS remains widely unknown. This study aimed to evaluate the relationship between plasma levels of IL-33, clinical and prognostic data and, IL-6 levels in 101 patients with MDS. A comparative group of 59 healthy individuals was also evaluated. Plasma levels of cytokines were determined by enzyme-linked immunosorbent assay. Lower levels of IL-33 were found in patients with MDS when compared to the control group (p = 0.001), mainly in patients with more advanced stages of the disease and worse prognosis. No significant correlation between the levels of IL-33 and IL-6 was observed (r = 0.175; p = 0.081). These results reinforce the close association between immunological disorders and the pathogenesis of MDS. A greater understanding of the role of inflammatory cytokines in the disease can potentially provide new diagnosis and prognosis markers and new therapeutic targets.

Role of the IL-33/ST2 receptor axis in ovarian cancer progression

Ovarian cancer remains a significant health problem for women in the world due to its diagnosis at advanced stages of disease and the high mortality rate of patients. To date, ovarian cancer is frequently treated with tumor reduction surgery followed by platinum/paclitaxel-based chemotherapy; however, most patients eventually develop relapsed disease. The mRNA expression levels of interleukin-33 (IL-33) and the suppressor of tumorigenicity 2 (ST2) receptor are significantly upregulated in ovarian cancer tissues and metastatic tumor lesions. In addition, IL-33 and ST2 expression has been associated with a poor overall survival in patients with epithelial ovarian cancer. The IL-33 receptor ST2 is expressed as both a membrane-anchored receptor (ST2L) activated by IL-33, and as a soluble variant that exhibits anti-inflammatory properties. In the present review, the functions of the IL-33/ST2L axis in cells and their aberrant expression levels in ovarian cancer were discussed. In addition, targeting their expression as a novel strategy for the control of ovarian cancer progression was emphasized.

PD-1 blockade combined with IL-33 enhances the antitumor immune response in a type-1 lymphocyte-mediated manner

PD-1 immune checkpoint blockade and cytokine IL-33 have shown significant therapeutic effects in tumor immunotherapy. These therapies promote CD8⁺ T cell activation, proliferation, and effector functions. However, there were few research about the combined therapy efficacy. In this study, we established B16-empty vector and B16-IL33 melanoma mouse models and treated with PD-1 monoclonal antibody. We reported that PD-1 blockade combined with cytokine IL-33 further inhibited tumor progression and prolonged the survival of tumor-bearing mice. Mechanistically, the combination therapy was found to further facilitate CD4⁺ and CD8⁺ T lymphocytes accumulation, and enhance the antitumor effects of CD4⁺or CD8⁺tumor-infiltrating lymphocytes by promoting type-1 immune response within the tumor microenvironment using flow cytometry and quantitative real time polymerase chain reaction. Thus, PD-1 blockade combined with IL-33 has application potential in tumor immunotherapy. Further, this study provides a new promising strategy and theoretical basis for tumor combination immunotherapy.

IL‑33/ST2 promotes the malignant progression of gastric cancer via the MAPK pathway

Gastric cancer (GC) remains one of the commonest malignant tumors and the second leading cause of cancer-related deaths worldwide. IL-33 is highly expressed in tumor tissues and serum of patients with GC. However, the function of the IL-33 and IL-33 receptor ST2 in the malignant progression of GC is yet to be elucidated. The present study aimed to explore the effect of the IL-33/ST2 axis on the biological functions of GC cells. The expression of ST2 in GC tissues was measured by immunohistochemistry. GC cell lines (AGS and MKN45) were treated with IL-33, and the expression of ST2 was downregulated by using specific siRNA. The effects of the IL-33/ST2 axis on cell proliferation, migration, invasion, cell cycle and apoptosis was detected by CCK8, Transwell, wound healing, flow cytometry and western blotting assays. The present study found that ST2 was highly expressed in GC tissues compared with normal tissues. IL-33 promoted the proliferation and cell cycle progression of GC cells, and upregulated the expression levels of CDK4, CDK6 and cyclin D1. Furthermore, IL-33 inhibited the apoptosis of GC cells and regulated the expression of apoptosis-associated proteins. In addition, IL-33 stimulated the invasion and migration of GC cells. However, the transfection of ST2 small interfering (si)RNA attenuated the effects of IL-33. Finally, IL-33 stimulation increased the phosphorylation levels of ERK1/2, JNK and p38. The transfection of ST2 siRNA could significantly inhibit the IL-33-induced ERK1/2, JNK and p38 activation. In conclusion, it was found that ST2 was highly expressed in GC tissues. IL-33/ST2 promoted the malignant progression of GC cells by inducing the activation of ERK1/2, JNK and p38.

IL-33 Promotes the Growth of Non-Small Cell Lung Cancer Cells Through Regulating miR-128-3p/CDIP1 Signalling Pathway

BACKGROUND

Non-small cell lung cancer (NSCLC) is one of the leading causes of cancer-related deaths, and it is also the most frequently diagnosed cancer. Previous studies indicate that IL-33 plays a crucial role in the development of NSCLC. In recent years, the role of miRNAs in cancer has become increasingly clear. However, reports focused on the relation between IL-33 and miRNAs in NSCLC have been limited.

METHODS

The expression of IL-33 and miR-128-3p was detected by qPCR. MTT, EdU, and colony formation assays were used to detect the proliferation ability of NSCLC cells. Transwell assay was used to investigate the migration and invasion of NSCLC cells. The expression of bax, cyt-c, and caspase 3 was detected by Western blot. Finally, in vivo tumor xenograft was used to detect the effects of IL-33 and miR-128-3p on tumor growth capacity.

RESULTS

IL-33 was notably increased in the serum and tumor tissue of NSCLC patients. The in vitro function study revealed that IL-33 significantly promotes the proliferation, migration, and invasion of the NSCLC cells. In vivo experiments further confirmed the pro-tumor effect of IL-33 on NSCLC. The study on the underlying mechanism elucidated that IL-33 regulates the expression of miR-128-3p, which can directly target and inhibit the expression of CDIP1. Furthermore, IL-33 regulates the expression of downstream apoptotic proteins such as bax, cyt-c, and caspase3. Rescue experiments demonstrated that miR-28-3p can reverse the effect of IL-33.

CONCLUSION

These findings indicated that IL-33 and miR-128-3p may play a potential role in the diagnosis and treatment of NSCLC.

Dual role of interleukin-33 in tumors

Interleukin-33 (IL-33) is a new member of the IL-1 cytokine family which plays roles in the nucleus as a nuclear factor and is released by damaged or necrotic cells to act as a cytokine. It can be released via damaged or necrotic cells and functions as a cytokine. The released IL-33 activates the downstream NF-κB and MAPKs signaling pathways through the isomers of the specific receptor ST2 and the interleukin-1 receptor accessory protein (IL-1RAcP), resulting in danger signals and the activated multiple immune responses. IL-33 is abnormally expressed in various tumors and involves in tumorigenesis, development, and metastasis. Moreover, IL-33 can play both pro-tumor and anti-tumor roles in the same type of tumor.

MicroRNA-488 inhibits proliferation and motility of tumor cells via downregulating FSCN1, modulated by Notch3 in breast carcinomas

As important modulators in multiple physiological processes, microRNAs (miRNAs) have been reported in various malignant tumors, including breast cancer. The current study investigated the function of a new tumor suppressor microRNA, miR-488, and its molecular mechanism of metastasis in breast cancers. CCK8 and transwell assays revealed that the upregulated miR-488 level significantly inhibited the proliferation and migration of breast cancer cells. As a potential downstream gene, the mRNA and protein level of FSCN1 was suppressed by increased miR-488 and vice versa. Luciferase assay showed that miR-488 directly bind to the 3'UTR of FSCN1 and suppressed the translation process of FSCN1. The promoter region of miR-488 was directly bound by Notch3 and promoted the expression of miR-488 transcriptionally. Immunohistochemistry results revealed that in patients with breast cancer, the expression of Notch3 and were negatively correlated with the FSCN1 levels significantly. Therefore, the current finding predicted miR-488 as a tumor suppressor molecule in breast cancer, and demonstrated that Notch3/miR-488/FSCN1 axis is established and involved in regulating the metastasis of breast cancers, providing novel therapeutic targets for patients with breast cancers.

High level of interleukin-33 in cancer cells and cancer-associated fibroblasts correlates with good prognosis and suppressed migration in cholangiocarcinoma

Interleukin 33 (IL-33) promotes cholangiocarcinoma (CCA) genesis in a mouse model, however, its function in human CCA has not been clearly understood. This study was aimed to investigate IL-33 level in CCA tissues and its clinicopathological correlations. The results revealed that IL-33 was found in both cancer cells and stromal cancer-associated fibroblast (CAFs) staining patterns which were divided into high (CH) and low level (CL) in cancer cells; and presence (FP) and absence (FA) in CAFs. Kaplan-Meier analysis showed that patients in the CL group were significantly correlated with a short 2-year survival time (P = 0.027). The CL/FP group had a shorter survival time compared to the other groups with statistical significance for 2-year (P = 0.030) and 5-year (P = 0.023) survivals. In contrast, CH/FP patients had significantly greater 2-year (P = 0.003) and 5-year (P = 0.003) survivals. Univariate and multivariate analysis confirmed that CL/FP was a significantly independent risk factor whereas CH/FP was a significant protective factor in CCA patients. High IL-33 expressing CCA cells had low migration, but they showed increased migration when IL-33 expression was knocked down. The low level of recombinant human IL-33 (rhIL-33) (0.002 - 2 ng/ml) could promote CCA cell migration, in contrast to the suppressive effect at a high dose (20 - 200 ng/ml). In conclusion, the combination of high IL-33 level in cancer cells and CAFs is a potentially good prognosis marker in CCA patients. The in vitro migration suppressive effect of IL-33 may be the potential mechanism supporting its role as a good prognostic marker in CCA patients. The obtained results strengthen IL-33 as a promising predictor and therapeutic target for CCA.

The Contradictory Role of Interleukin-33 in Immune Cells and Tumor Immunity

Interleukin (IL)-33 is a member of the IL-1 superfamily and is a crucial cytokine playing the role of a dual-function molecule. IL-33 mediates its function by interacting with its receptor suppression of tumorigenicity 2 (ST2), which is constitutively expressed on T helper (Th)1 cells, Th2 cells, and other immune cells. Previously, we summarized findings on IL-33 and performed an intensive study of the correlation between IL-33 and tumor. IL-33 enables anti-tumor immune responses through Th1 cells and natural killer (NK) cells and plays a role in tumor immune escape in cancers via Th2 cells and regulatory T cells. Herein, we discuss the contradictory role of IL-33 in immune cells in different cancer, and our summaries may be helpful for better understanding of the development of research on IL-33 and tumor immunity.

Interleukin‑33 expression in ovarian cancer and its possible suppression of peritoneal carcinomatosis

Refractory peritoneal carcinomatosis is a common terminal feature of epithelial ovarian cancer (EOC). Previous reports have suggested that immunotherapy is a promising therapeutic strategy for EOC. Interleukin (IL)‑33 is a member of the IL‑1 superfamily of cytokines. The role of IL‑33 in tissue inflammation and promoting type 2 immune responses has been established, and recently, there is accumulating evidence to suggest the involvement of IL‑33 in carcinogenesis. In this study, we focused on the association between the tumor expression of IL‑33 and ovarian peritoneal carcinomatosis. We used an immunosufficient murine model of peritoneal carcinomatosis and human EOC samples. The overexpression of IL‑33 in the ID8 mouse EOC cell line tumors significantly prolonged the survival of immunocompetent mice in the peritoneal carcinomatosis setting, but not in the subcutaneous model. In addition, the silencing of IL‑33 in ID8‑T6 cells (subclone with high dissemination potential) significantly shortened the survival of the tumor‑bearing mice. This was likely due to the intratumoral accumulation of CD8+ and CD4+ T cells, and a decrease in CD11b+Gr1+ cells. Furthermore, IL‑33 induced the intraperitoneal microenvironment favoring tumor elimination through the inhibition of differentiation into CD11b+Gr1+ cells. On the whole, the findings of this study suggest IL‑33 to be a cytokine that reflects antitumor peritoneal conditions. Further investigation of the antitumorigenic role of IL‑33 may aid in the development of more effective therapeutic approaches for the treatment of EOC with peritoneal carcinomatosis.

Interleukin 33/ST2 Axis Components Are Associated to Desmoplasia, a Metastasis-Related Factor in Colorectal Cancer

In colorectal cancer (CRC), cancer-associated fibroblasts (CAFs) are the most abundant component from the tumor microenvironment (TM). CAFs facilitate tumor progression by inducing angiogenesis, immune suppression and invasion, thus altering the organization/composition of the extracellular matrix (i.e., desmoplasia) and/or activating epithelial-mesenchymal transition (EMT). Soluble factors from the TM can also contribute to cell invasion through secretion of cytokines and recently, IL-33/ST2 pathway has gained huge interest as a protumor alarmin, promoting progression to metastasis by inducing changes in TM. Hence, we analyzed IL-33 and ST2 content in tumor and healthy tissue lysates and plasma from CRC patients. Tissue localization and distribution of these molecules was evaluated by immunohistochemistry (using localization reference markers α-smooth muscle actin or α-SMA and E-cadherin), and clinical/histopathological information was obtained from CRC patients. In vitro experiments were conducted in primary cultures of CAFs and normal fibroblasts (NFs) isolated from tumor and healthy tissue taken from CRC patients. Additionally, migration and proliferation analysis were performed in HT29 and HCT116 cell lines. It was found that IL-33 content increases in left-sided CRC patients with lymphatic metastasis, with localization in tumor epithelia associated with abundant desmoplasia. Although ST2 content showed similarities between tumor and healthy tissue, a decreased immunoreactivity was observed in left-sided tumor stroma, associated to metastasis related factors (advanced stages, abundant desmoplasia, and presence of tumor budding). A principal component analysis (including stromal and epithelial IL-33/ST2 and α-SMA immunoreactivity with extent of desmoplasia) allowed us to distinguish clusters of low, intermediate and abundant desmoplasia, with potential to develop a diagnostic signature with benefits for further therapeutic targets. IL-33 transcript levels from CAFs directly correlated with CRC cell line migration induced by CAFs conditioned media, with rhIL-33 inducing a mesenchymal phenotype in HT29 cells. These results indicate a role of IL-33/ST2 in tumor microenvironment, specifically in the interaction between CAFs and epithelial tumor cells, thus contributing to invasion and metastasis in left-sided CRC, most likely by activating desmoplasia.

Stromal interleukin-33 promotes regulatory T cell-mediated immunosuppression in head and neck squamous cell carcinoma and correlates with poor prognosis

Regulatory T cells (Tregs) mediate immunosuppressive signals that can contribute to the progression of head and neck squamous cell carcinoma (HNSCC). Interleukin-33 (IL-33) is defined as an 'alarmin', an endogenous factor that is expressed during tissue and cell damage, which has been shown to promote Treg proliferation in non-lymphoid organs. However, the interaction between IL-33 and Tregs in the HNSCC tumor microenvironment remains uncertain. In this study, we examined IL-33+ and Foxp3+ cells by immunohistochemistry in 68 laryngeal squamous cell cancer patients, followed by functional analysis of IL-33 in Tregs. In addition, the suppressive function of Tregs was assessed by cell proliferation assays. The level of stromal IL-33 was significantly upregulated in advanced versus early stage HNSCC patients and positively correlated with Foxp3+ Treg infiltration as well as a poor prognosis. ST2 is regarded as the only receptor of IL-33. Infiltrated ST2-expressing Tregs were responsive to IL-33, and the percentage of Tregs was increased upon IL-33 stimulation. Functional investigation demonstrated that IL-33 increased the proportion of Foxp3+GATA3+ Tregs and improved the suppressive functions of Tregs by inducing IL-10 and TGF-β1 as well as decreasing the proliferation of responder T cells. Blockade of ST2 abrogated the immunosuppression caused by IL-33. Our data demonstrate that stromal IL-33 both expands the Treg population and enhances their functions in the tumor microenvironment. Furthermore, stromal IL-33 has prognostic value for tumor progression. Thus, stromal IL-33 is a potential target for future HNSCC immunotherapy.

Increased Expression of sST2 in Early HIV Infected Patients Attenuated the IL-33 Induced T Cell Responses

T cell responses were less functional and persisted in an exhausted state in chronic HIV infection. Even in early phase of HIV infection, the dysfunction of HIV-specific T cells can be observed in rapid progressors, but the underlying mechanisms are not fully understood. Cytokines play a central role in regulating T cell function. In this study, we sought to elucidate whether IL-33/ST2 axis plays roles in the regulation of T cell function in HIV infection. We found that the level of IL-33 was upregulated in early HIV-infected patients compared with that in healthy controls and has a trend associated with disease progression. In vitro study shows that IL-33 promotes the expression of IFN-γ by Gag stimulated CD4+ and CD8+T cells from HIV-infected patients to a certain extent. However, soluble ST2 (sST2), a decoy receptor of IL-33, was also increased in early HIV infected patients, especially in those with progressive infection. We found that anti-ST2 antibodies attenuated the effect of IL-33 to CD4+ and CD8+T cells. Our data indicates that elevated expression of IL-33 in early HIV infection has the potential to enhance the function of T cells, but the upregulated sST2 weakens the activity of IL-33, which may indirectly contribute to the dysfunction of T cells and rapid disease progression. This data broadens the understanding of HIV pathogenesis and provides critical information for HIV intervention.

Contribution of IL-33 to the Pathogenesis of Colorectal Cancer

The development of colorectal cancer (CRC) is not only determined by transformed cells per se, but also by factors existing in their immune microenvironment. Accumulating scientific evidence has revealed that interleukin (IL)-33, an IL-1 family member, plays an essential role in the regulation of immune response and is relevant in CRC pathogenesis. Data from both human and experimental studies demonstrated that IL-33 inhibits host anti-tumor immunity, remodels tumor stroma and enhances angiogenesis, thereby promoting the development of CRC. These pro-tumor effects of IL-33 are mainly mediated by IL-33 receptor ST2 (also known as IL-1RL1). Based on those findings, it is currently hypothesized that the IL-33/ST2 pathway is a potential biomarker and therapeutic target for colorectal tumorigenesis. Herein, we summarize the recent discoveries in understanding the critical role of the IL-33/ST2 pathway in contributing to the pathogenesis of colorectal tumorigenesis and discuss its potential implications for the future development of effective anti-tumor strategies.

IL-33 Released in the Liver Inhibits Tumor Growth via Promotion of CD4+ and CD8+ T Cell Responses in Hepatocellular Carcinoma

IL-33 released by epithelial cells and immune cells functions as an alarmin and can induce both type 1 and type 2 immune responses. However, the role of IL-33 release in tumor development is still not clear. In this study, we examined the function of released IL-33 in murine hepatocellular carcinoma (HCC) models by hydrodynamically injecting either IL-33-expressing tumor cells or IL-33-expressing plasmids into the liver of tumor-bearing mice. Tumor growth was greatly inhibited by IL-33 release. This antitumor effect of IL-33 was dependent on suppression of tumorigenicity 2 (ST2) because it was diminished in ST2^-/- mice. Moreover, HCC patients with high IL-33 expression have prolonged overall survival compared with the patients with low IL-33 expression. Further study showed that there were increased percentages and numbers of activated and effector CD4⁺ and CD8⁺ T cells in both spleen and liver in IL-33-expressing tumor-bearing mice. Moreover, IFN-γ production of the CD4⁺ and CD8⁺ T cells was upregulated in both spleen and liver by IL-33. The cytotoxicity of CTLs from IL-33-expressing mice was also enhanced. In vitro rIL-33 treatment could preferentially expand CD8⁺ T cells and promote CD4⁺ and CD8⁺ T cell activation and IFN-γ production. Depletion of CD4⁺ and CD8⁺ T cells diminished the antitumor activity of IL-33, suggesting that the antitumor function of released IL-33 was mediated by both CD4⁺ and CD8⁺ T cells. Taken together, we demonstrated in murine HCC models that IL-33 release could inhibit tumor development through its interaction with ST2 to promote antitumor CD4⁺ and CD8⁺ T cell responses.

The Pleiotropic Immunomodulatory Functions of IL-33 and Its Implications in Tumor Immunity

Interleukin-33 (IL-33) is a IL-1 family member of cytokines exerting pleiotropic activities. In the steady-state, IL-33 is expressed in the nucleus of epithelial, endothelial, and fibroblast-like cells acting as a nuclear protein. In response to tissue damage, infections or necrosis IL-33 is released in the extracellular space, where it functions as an alarmin for the immune system. Its specific receptor ST2 is expressed by a variety of immune cell types, resulting in the stimulation of a wide range of immune reactions. Recent evidences suggest that different IL-33 isoforms exist, in virtue of proteolytic cleavage or alternative mRNA splicing, with potentially different biological activity and functions. Although initially studied in the context of allergy, infection, and inflammation, over the past decade IL-33 has gained much attention in cancer immunology. Increasing evidences indicate that IL-33 may have opposing functions, promoting, or dampening tumor immunity, depending on the tumor type, site of expression, and local concentration. In this review we will cover the biological functions of IL-33 on various immune cell subsets (e.g., T cells, NK, Treg cells, ILC2, eosinophils, neutrophils, basophils, mast cells, DCs, and macrophages) that affect anti-tumor immune responses in experimental and clinical cancers. We will also discuss the possible implications of diverse IL-33 mutations and isoforms in the anti-tumor activity of the cytokine and as possible clinical biomarkers.

Interleukins Associated with Breast Cancer

A tumor consists of a group of cells with abnormal growth, capable of acquiring unique characteristics that provide them with the ability to display mercurial migration patterns, adapting to microenvironments and their chemical and physical factors. Interleukins are small proteins secreted mainly by CD3+ and CD4+ T lymphocytes that mediate the "essential for cancer progression" interactions between cells. Interleukins are implicated in both the development and differentiation of different cells (NK, B, and T leukocytes) and, in general, play a major role in many diseases, including breast cancer, due to their unique participation in systemic inflammation and immune system modulation. During the past decade, interleukins proved to be decisive for future immunotherapy, predisposing a more reliable treatment with fewer side effects on normal proliferating cells. The aim of this review is to provide an overview of the role of interleukins implicated in breast cancer progression.

The Pro-tumorigenic IL-33 Involved in Antitumor Immunity: A Yin and Yang Cytokine

Interleukin-33 (IL-33), considered as an alarmin released upon tissue stress or damage, is a member of the IL-1 family and binds the ST2 receptor. First described as a potent initiator of type 2 immune responses through the activation of T helper 2 (T_H2) cells and mast cells, IL-33 is now also known as an effective stimulator of T_H1 immune cells, natural killer (NK) cells, iNKT cells, and CD8 T lymphocytes. Moreover, IL-33 was shown to play an important role in several cancers due to its pro and anti-tumorigenic functions. Currently, IL-33 is a possible inducer and prognostic marker of cancer development with a direct effect on tumor cells promoting tumorigenesis, proliferation, survival, and metastasis. IL-33 also promotes tumor growth and metastasis by remodeling the tumor microenvironment (TME) and inducing angiogenesis. IL-33 favors tumor progression through the immune system by inducing M2 macrophage polarization and tumor infiltration, and upon activation of immunosuppressive cells such as myeloid-derived suppressor cells (MDSC) or regulatory T cells. The anti-tumor functions of IL-33 also depend on infiltrated immune cells displaying T_H1 responses. This review therefore summarizes the dual role of this cytokine in cancer and suggests that new proposals for IL-33-based cancer immunotherapies should be considered with caution.

Interleukin-33 and ST2 Signaling in Tumor Microenvironment

Interleukin-33 (IL-33) is one of the members of the IL-1 family of cytokines and a ligand of ST2 and IL-1 receptor accessory protein (IL-1RAcP) that is known to affect Th2 inflammatory response with partial effects on Th1 responses. This cytokine is released by epithelial and smooth muscle cells of the airway system during their injury by several environmental stimuli, such as allergens, viruses, helminths, and pollutants. IL-33 is an alarmin that acts as an endogenous danger signal, and it has been known to affect various types of cells, such as mast cells, basophils, eosinophils, T cells, and specific subsets of innate lymphoid cells (ILCs). In recent findings, this cytokine is believed to have a critical role in several types of cancers, such as lung cancer, liver cancer, and head and neck squamous cell cancer. The expression of IL-33/ST2 in cancer tissues shows a close association with tumor growth and tumor progression in several types of cancer, suggesting the IL-33/ST2 pathway as a potential target for therapy.

The Role of IL-33/ST2 Pathway in Tumorigenesis

Cancer is initiated by mutations in critical regulatory genes; however, its progression to malignancy is aided by non-neoplastic cells and molecules that create a permissive environment known as the tumor stroma or microenvironment (TME). Interleukin 33 (IL-33) is a dual function cytokine that also acts as a nuclear factor. IL-33 typically resides in the nucleus of the cells where it is expressed. However, upon tissue damage, necrosis, or injury, it is quickly released into extracellular space where it binds to its cognate receptor suppression of tumorigenicity 2 (ST2)L found on the membrane of target cells to potently activate a T Helper 2 (Th2) immune response, thus, it is classified as an alarmin. While its role in immunity and immune-related disorders has been extensively studied, its role in tumorigenesis is only beginning to be elucidated and has revealed opposing roles in tumor development. The IL-33/ST2 axis is emerging as a potent modulator of the TME. By recruiting a cohort of immune cells, it can remodel the TME to promote malignancy or impose tumor regression. Here, we review its multiple functions in various cancers to better understand its potential as a therapeutic target to block tumor progression or as adjuvant therapy to enhance the efficacy of anticancer immunotherapies.

Extracts of Cordyceps sinensis inhibit breast cancer cell metastasis via down-regulation of metastasis-related cytokines expression

ETHNOPHARMACOLOGICAL RELEVANCE

Cordyceps sinensis is a traditional Chinese medicine and has been used as adjuvant treatments for cancer and it has been also demonstrated to be effective in cancer patients.

AIM OF THE STUDY

The objective of the present study is to investigate the anti-metastasis effects of water extracts of Cordyceps sinensis (WECS) in breast cancer and the potential mechanisms.

MATERIALS AND METHODS

The cytotoxicity of WECS on 4T1 breast cancer cells was evaluated in vitro using cell counting kit-8 (CCK8) assay. The in vivo anti-metastatic activity of intraperitoneally administered WECS and its effect on animal survival were measured in a mouse breast cancer metastasis model. To explore the molecular mechanisms of the anti-metastasis effect of WECS, the expression of matrix metalloprotein-9 (MMP-9) in serum was determined by enzyme-linked immunosorbent assay (ELISA). In addition, a protein array was used to examine the cytokine expression profiles in lung homogenates.

RESULTS

Treatment with WECS (0.10-0.40mg/ml) significantly inhibited 4T1 cell viability in vitro. In animal studies, 50mg/kg WECS significantly reduced the number of metastatic lung nodules and the weight of lung, without affecting body weight of mice. Furthermore, WECS increased the survival rate of 4T1 tumor bearing mice in a dose dependent manner, and at high dose, WECS (50mg/kg) significantly increased the life span of the mice compared to untreated control group. The expression level of MMP-9 in serum was decreased about 50% in 50mg/kg WECS treated group compared to control group. The results of protein array showed that the expression of CC chemokine ligand 17 (CCL17), MMP-9, osteopontin (OPN), interleukin-33 (IL-33), CC chemokine ligand 12 (CCL12) and CC chemokine ligand 6 (CCL6) in the lungs of 4T1 tumor bearing mice was increased more than two fold compared with normal mice. Among them, the expression of CCL17, MMP-9, OPN, IL-33 was significantly reduced by treatment of 50mg/kg WECS.

CONCLUSION

Our results demonstrated that WECS has potent anti-metastasis activity in a mouse breast cancer metastasis model possibly by down-regulation the expression of several metastasis-related cytokines.

MicroRNAs as Potential Serum Biomarkers for Early Detection of Ectopic Pregnancy

Diagnosis of ectopic pregnancy relies on both ultrasound findings and human chorionic gonadotropin (hCG) measurements but due to the need for serial tests, tubal rupture and death represent major maternal and fetal risks. Early detection of ectopic pregnancy is essential and thus a noninvasive diagnostic tool seems crucial for the prevention of adverse effects since studies suggest there is a specific relationship between ectopic pregnancy and increasing microRNA factors. Human fluids in women with ectopic pregnancy reveal a particular change in comparison to healthy women. In addition to certain placental microRNAs circulating through plasma that present a specific concentration and serum profile, microRNAs seem to be possible biomarkers for the detection of pregnancy complications linked to placental pathologies. The aim of this study is to review current literature considering the expression levels of several circulating microRNAs that have shown to be novel potential biomarkers for the diagnosis of tubal ectopic pregnancy.

Lower expression level of IL-33 is associated with poor prognosis of pulmonary adenocarcinoma

Objective

Lung cancer is one of the deadliest malignancies. The immune checkpoint-blockade (ICB) tumor therapy has led to striking improvement of long-term survival for some lung cancer patients. However, the response rate of immunotherapy is still low for lung cancer. Studying the tumor microenvironment (TME) should shed light on improvement of immunotherapy of lung cancer. Interleukin-33 (IL-33), an “alarmin” cytokine, has been implicated in tumor associated immune responses and inflammatory diseases of the lung. The role of IL-33 in lung cancer progression, however, remains elusive. This study is designed to characterize IL-33 expression in lung tumor tissues and establish the clinical significance of IL-33 in non-small cell lung cancer lung cancer (NSCLC).

Materials and methods

Tumor tissue specimens from patients suffering from NSCLC were analyzed for expression of IL-33 protein by immunohistochemistry and expression of IL-33 and ST2 mRNA by RT-quantitative PCR (RT-QPCR). The expression data were analyzed for their association with clinical and pathological parameters of NSCLC. In addition, the association between expression levels of IL-33 mRNA and patient survival was determined using 5 independent expression profiling datasets of human lung cancer.

Results and conclusion

The expression levels of IL-33 and ST2 were significantly down-regulated in both adenocarcinoma and squamous cell carcinoma of the lung when compared to adjacent normal lung tissues. In addition, the level of IL-33 protein was inversely correlated with tumor grade and size. Moreover, analysis of TCGA and GEO lung cancer expression datasets revealed that higher expression levels of IL-33 mRNA were correlated with longer overall survival of patients suffering from adenocarcinoma of the lung. These data indicate that the expression levels of IL-33 are inversely associated with lung cancer progression, consistent with the hypothesis that IL-33 is involved in immune surveillance of NSCLC.

Interleukin-33 in Malignancies: Friends or Foes?

The human Interleukin-33 (IL-33), a member of the IL-1 family, is the cytokine as a cell endogenous alarmin, released by damaged or necrotic barrier cells (endothelial and epithelial cells). The signal transduction of IL-33 relies on recognition and interaction with specific receptor ST2, mainly expressed in immune cells. In both innate and adoptive immunity, IL-33 regulates the homeostasis in response to stress from within/out the microenvironment. Various, even negative biofunctions of IL-33 pathways have now been widely verified in pathogenesis among immunological mechanisms, like Th2-related immune-stimuli, inflammation/infection-induced tissue protectors. A larger versatility in studies of IL-33 on malignancies now focuses on: (1) promoting myeloid-derived suppressor cells (MDSC), (2) intervention toward CD8⁺ T, Natural Killer (NK) cell infiltration, group 2 innate lymphoid cells (ILC2) proliferation, dendritic cells (DC) activation, and (3) inhibiting tumor growth and/or further metastasis as an immunoadjuvant. Although IL-33 functioned pro-tumorigenically in various cancers, for some cancer types the findings so far are controversial. This review begins from a summarized introduction of IL-33, to its remarkable implications and molecular transduction pathway in malignant neoplasms, ends with latest inspiration for IL-33 in treatment.

IL-33 facilitates endocrine resistance of breast cancer by inducing cancer stem cell properties

Breast cancers with estrogen receptor (ER) expressions account for the majority of all clinical cases. Due to hormone therapy with tamoxifen, prognoses of patients with ER-positive breast cancer are significantly improved. However, endocrine resistance to tamoxifen is common and inevitable, leading to compromised efficacy of hormone therapy. Herein, we identify a crucial role of IL-33 in inducing endocrine resistance of breast cancer. IL-33 overexpression in breast cancer cells results in resistance to tamoxifen-induced tumor growth inhibition, while IL-33 knockdown corrects this problem. Mechanistically, IL-33 induces breast cancer stem cell properties evidenced by mammosphere formation and xenograft tumorigenesis, as well as expression of cancer stem cell genes including ALDH1A3, OCT4, NANOG and SOX2. In breast cancer patients, higher serum IL-33 levels portend advanced clinical stages, poorly differentiated cancer cells and tumor recurrence. IL-33 expression levels in patients' freshly isolated breast cancer cells predicts tamoxifen resistance and cancer stem cell features in individual patient. Collectively, IL-33 induces endocrine resistance of breast cancer by promoting cancer stem cell properties. These findings provide novel mechanisms connecting IL-33 with cancer pathogenesis and pinpoint IL-33 as a promising target for optimizing hormone therapy in clinical practice.

The role and prognostic value of inducible nitric oxide synthase (iNOS) and interleukin-33 (IL-33) in serous and mucinous epithelial ovarian tumours

Understanding different mechanisms contributing to the aggressive behaviour of epithelial ovarian cancer (EOC) is a large challenge. Interaction between inflammation, immunity and carcinogenesis occurs in different cancers; however, the potential roles of different molecules involved in these processes in relation to ovarian carcinogenesis were not fully investigated. Inducible nitric oxide synthase (iNOS) and interleukin-33 (IL-33) are implicated in carcinogenesis. iNOS is an NOS isoform that generates nitric oxide, which plays important roles in various stages of carcinogenesis. IL-33 is a cytokine implicated in modulation of anti-tumour immunity and tumour growth. This work aimed at studying the immunohistochemical expression of iNOS and IL-33 in serous and mucinous epithelial ovarian tumours to investigate their role and prognostic significance. Immunohistochemical expressions of iNOS and IL-33 were assessed in 90 patients with epithelial ovarian tumours (45 serous and 45 mucinous tumours, categorized as benign, borderline, and malignant tumours). iNOS and IL-33 showed significantly higher expressions in borderline and malignant serous and mucinous tumours compared to benign ones (p=0.0001). The differences between borderline and malignant tumours were statistically insignificant (p=0.2351&0.6321). iNOS showed significantly higher expression with increasing tumour grade in malignant mucinous tumours (p=0.0011). IL-33 showed significantly higher expression with increasing tumour grade in both malignant serous and mucinous tumours (p=0.0074 and 0.0007). Upregulation of iNOS and IL-33 expression in borderline and malignant epithelial ovarian tumours indicates their involvement in the development and progression of EOC, and their increased expression in less differentiated cancers suggests their association with poor prognosis in this category of tumours.

The Role of IL-33-Dependent Inflammation in the Tumor Microenvironment

There is compelling evidence that inflammation contributes to tumorigenesis. Inflammatory mediators within the tumor microenvironment can either promote an antitumor immune response or support tumor pathogenesis. Therefore, it is critical to determine the relative contribution of tumor-associated inflammatory pathways to cancer development. Interleukin-33 (IL-33) is a member of the IL-1 family of cytokines that is released upon tissue stress or damage to operate as an alarmin. IL-33 has been primarily implicated in the induction of type-2 immune responses. However, recent findings have shown a role of IL-33 in several cancers where it may exert multiple functions. In this review, we will present the current knowledge on the role of IL-33 in the microenvironment of different tumors. We will highlight which cells produce and which cells are activated by IL-33 in cancer. Furthermore, we will explain how IL-33 modulates the tumor-associated inflammatory microenvironment to restrain or promote tumorigenesis. Finally, we will discuss the issues to be addressed first before potentially targeting the IL-33 pathway for cancer therapy.

Deletion of IL-33R attenuates VEGF expression and enhances necrosis in mammary carcinoma

Interleukin-33 (IL-33)/IL-33 receptor (IL-33R, ST2) signaling pathway promotes mammary cancer growth and metastasis by inhibiting anti-tumor immunity. However, the role of IL-33/IL-33R axis in neoangiogenesis and tumor necrosis is not elucidated. Therefore, the aim of this study was to investigate the role of IL-33/IL-33R axis in mammary tumor necrosis. Deletion of IL-33R (ST2) gene in BALB/c mice enhanced tumor necrosis and attenuated tumor growth in 4T1 breast cancer model, which was associated with markedly decreased expression of vascular endothelial growth factor (VEGF) and IL-33 in mammary tumor cells. We next analyzed IL-33, IL-33R and VEGF expression and microvascular density (MVD) in breast tumors from 40 female patients with absent or present tumor necrosis. We found significantly higher expression of IL-33, IL-33R and VEGF in breast cancer tissues with absent tumor necrosis. Both, IL-33 and IL-33R expression correlated with VEGF expression in tumor cells. Further, VEGF expression positively correlated with MVD in perinecrotic zone. Taking together, our data indicate that IL-33/IL-33R pathway is critically involved in mammary tumor growth by facilitating expression of pro-angiogenic VEGF in tumor cells and attenuating tumor necrosis. These data add an unidentified mechanism by which IL-33/IL-33R axis facilitates tumor growth.

Discovery of a Metastatic Immune Escape Mechanism Initiated by the Loss of Expression of the Tumour Biomarker Interleukin-33

A new paradigm for understanding immune-surveillance and immune escape in cancer is described here. Metastatic carcinomas express reduced levels of IL-33 and diminished levels of antigen processing machinery (APM), compared to syngeneic primary tumours. Complementation of IL-33 expression in metastatic tumours upregulates APM expression and functionality of major histocompatibility complex (MHC)-molecules, resulting in reduced tumour growth rates and a lower frequency of circulating tumour cells. Parallel studies in humans demonstrate that low tumour expression of IL-33 is an immune biomarker associated with recurrent prostate and kidney renal clear cell carcinomas. Thus, IL-33 has a significant role in cancer immune-surveillance against primary tumours, which is lost during the metastatic transition that actuates immune escape in cancer.

Role of IL-33 expression in oncogenesis and development of human hepatocellular carcinoma

Interleukin-33 (IL-33), a newly-discovered cytokine belonging to the IL-1 family, serves an important role in inflammation. However, it is not clear whether IL-33 is of clinical significance in hepatocarcinogenesis. The present study was designed to investigate the role of IL-33 during oncogenesis and development of hepatocellular carcinoma (HCC). IL-33 protein expression was detected in 76 HCC (including 36 para-carcinoma), 33 cirrhosis, 30 hepatitis, and 20 normal liver tissues using immunohistochemistry. IL-33 mRNA expression in carcinoma and para-carcinoma tissues was evaluated by reverse transcription-polymerase chain reaction (RT-PCR). The possible correlation between IL-33 and clinicopathological parameters of HCC was also analyzed. Significant differences in IL-33 expression were not observed among normal, hepatic, and cirrhotic tissues (P>0.05), whereas the level of protein positive rate was markedly reduced in HCC tissues (P<0.01). Positive staining of IL-33 in non-cancerous liver (NCL) tissues (i.e. normal, hepatitis, and liver cirrhosis) was located predominantly in the nucleus and occasionally in the cytoplasm of hepatocytes; however, the expression in HCC tissues was mostly restricted to the cytoplasm. A significant alteration in protein localization was observed in HCC tissues as compared with NCL tissues (P<0.01). In comparison with HCC tissues, cytoplasmic staining of IL-33 was increased in para-carcinoma tissues. RT-PCR assay further confirmed relatively high mRNA expression levels of IL-33 in para-carcinoma tissues. IL-33 expression was significantly negatively associated with tumor histological grade (r=−0.279, P=0.015), but not with year, gender, tumor size, clinical stage, HCC with hepatitis and cirrhosis background, lymph node metastasis or intrahepatic vascular embolism (P>0.05). Therefore, the aberrant expression of IL-33 is associated with oncogenesis and progression of HCC and the cytoplasmic accumulation of the protein may serve a role in hepatocarcinogenesis.