Clinical implications of the novel cytokine IL-38 expressed in lung adenocarcinoma: Possible association with PD-L1 expression

IL-38 promotes the development of prostate cancer

Introduction

Prostate Cancer (PCa) remains a significant concern in male cancer-related mortality. Tumour development is intricately regulated by the complex interactions between tumour cells and their microenvironment, making it essential to determine which is/are key factor(s) that influence the progression of PCa within the tumour microenvironment.

Materials and methods

The current study utilised histopathology and immunohistochemistry to determine the expression of IL-38 in PCa and analysed the correlation between the expression level of IL-38 within PCa and clinical pathological characteristics.

Results

There was a significant increase in IL-38 expression in PCa tissues compared to adjacent non-PCa tissues (P < 0.0001). In addition, IL-38 expression was significantly higher in tumour cells with a high proliferation index compared to those with a low value-added index. ROC curve analysis demonstrated that IL-38 has high specificity and sensitivity for the diagnosis of PCa (AUC=0.76). Moreover, we Probed the cellular source of IL-38 in prostate cancer tissue by immunofluorescence double staining. Additionally, within PCa, the expression of IL-38 was inversely correlated with the expression levels of CD8 and PD-1. Survival analysis revealed a significantly lower overall survival rate for PCa patients with high IL-38 expression (P=0.0069), and when IL-38 was co-expressed with CD8, the survival rate of the IL-38high/CD8low group was decreased significantly. Multivariate analysis indicated that the expression level of IL-38 and TNM staging were independent predictors of survival in PCa patients.

Conclusion

These findings suggest that IL-38 plays a crucial role in the development of PCa, and the exploration of the correlation between IL-38 and various immune factors in the tumour microenvironment further reveals its mechanism of action, making it a potential target for immunotherapy in PCa.

The emerging role of IL-38 in diseases: A comprehensive review

INTRODUCTION

Interleukin-38 (IL-38) is a new type of anti-inflammatory cytokine, which is mainly expressed in the immunity-related organs and is involved in various diseases including cardiovascular and cerebrovascular diseases, lung diseases, viral infectious diseases and autoimmune diseases.

AIM

This review aims to detail the biological function, receptors and signaling of IL-38, which highlights its therapeutic potential in related diseases.

CONCLUSION

This article provides a comprehensive review of the association between interleukin-38 and related diseases, using interleukin-38 as a keyword and searching the relevant literature through Pubmed and Web of science up to July 2023.

IL-36 expression is increased in NSCLC with IL-36 stimulation of lung cancer cells promoting a pro-tumorigenic phenotype

The IL-36 cytokines are a recently described subset of the IL-1 family of cytokines, and have been shown to play a role in the pathogenesis of respiratory diseases such as asthma and COPD. Given the common aetiological links between COPD and lung cancer development, as well as the involvement of other IL-1 family members in lung tumorigenesis, the aim of this work was to investigate the role of IL-36 cytokines in the pathogenesis of lung cancer. In this study we demonstrate that expression of IL-36 cytokines and receptor mRNA and protein are significantly increased in lung cancer tissue compared to adjacent non-tumour tissue. In vitro assays showed that stimulation of two lung cancer cell lines, SKMES-1 human squamous cell and LLC murine lung cancer, with IL-36R agonists resulted in increased cellular migration and proliferation. All IL-36 cytokines induced the expression of pro-inflammatory chemokines in both lung cancer cell lines with synergistic effects identified upon co-stimulation of cells with IL-17, IL-22 and TNFα. Furthermore, we report that IL-36 cytokines induce protein expression of the immune checkpoint inhibitor protein PD-L1 on lung cancer cells. Taken together, this data indicates that targeting IL-36R signalling may be a useful targeted therapy for lung cancer patients with IL-36R⁺ cancer cells.

Serum interleukin-38 and -41 levels as candidate biomarkers in male infertility

BACKGROUND

Interleukin (IL)-38 and IL-41 are novel cytokines, but their role in male infertility (MI) is unknown. The purpose of this study was to measure the levels of serum IL-38 and IL-41 in patients with MI and correlate these levels with semen indexes.

METHODS

Eighty-two patients with MI and 45 healthy controls (HC) were recruited for this study. Semen parameters were detected using computer-aided sperm analysis, Papanicolaou staining, ELISA, flow cytometry, peroxidase staining and enzyme methods. Serum IL-38 and IL-41 levels were determined by ELISA.

RESULTS

Serum IL-38 levels were decreased (P < 0.01) in patients with MI compared with HC. Serum IL-41 levels were significantly higher in patients with MI than in HC (P < 0.0001). In patients with MI, serum IL-38 levels were positively correlated with semen white blood cell counts (r = 0.29, P = 0.009), and there was a positive correlation between semen white blood cell counts and sperm concentration (r = 0.28, P = 0.0100) and seminal plasma elastase (r = 0.67, P < 0.0001). Receiver operating characteristic curve analysis showed that the area under the curve of IL-38 for diagnosing MI was 0.5637 (P > 0.05), and the area under the curve of IL-41 for diagnosing MI was 0.7646 (P < 0.0001).

CONCLUSIONS

Serum IL-38 levels were significantly lower, and serum IL-41 levels were higher in patients with MI. These results suggest that IL-38 and IL-41 may be novel biomarkers for the diagnosis of MI.

Head and Neck Cancer Immunotherapy: Molecular Biological Aspects of Preclinical and Clinical Research

Breakthrough research in the field of immune checkpoint inhibitors and the development of a human papilloma virus vaccine triggered a plethora of research in the field of cancer immunotherapy. Both had significant effects on the treatment of head and neck squamous cell carcinoma. The advent of preclinical models and multidisciplinary approaches including bioinformatics, genetic engineering, clinical oncology, and immunology helped in the development of tumour-infiltrating lymphocytes (TILs) and chimeric antigen receptor (CAR) T-cell therapy. Here, we discuss different immunotherapies such as adoptive T-cell transfer, immune checkpoint inhibitors, interleukins, and cancer vaccines for the treatment of head and neck cancer. This review showcases the intrinsic relation between the understanding and implementation of basic biology and clinical practice. We also address potential limitations of each immunotherapy approach and the advantages of personalized immunotherapy. Overall, the aim of this review is to encourage further research in the field of immunotherapy for head and neck cancer.

IL-38 blockade induces anti-tumor immunity by abrogating tumor-mediated suppression of early immune activation

Immune checkpoint inhibitors that overcome T cell suppressive mechanisms in tumors have revolutionized the treatment of cancer but are only efficacious in a small subset of patients. Targeting suppressive mechanisms acting on innate immune cells could significantly improve the incidence of clinical response by facilitating a multi-lineage response against the tumor involving both adaptive and innate immune systems. Here, we show that intra-tumoral interleukin (IL)-38 expression is a feature of a large frequency of head and neck, lung and cervical squamous cancers and correlates with reduced immune cell numbers. We generated IMM20324, an antibody that binds human and mouse IL-38 proteins and inhibits the binding of IL-38 to its putative receptors, interleukin 1 receptor accessory protein-like 1 (IL1RAPL) and IL-36R. In vivo, IMM20324 demonstrated a good safety profile, delayed tumor growth in a subset of mice in an EMT6 syngeneic model of breast cancer, and significantly inhibited tumor expansion in a B16.F10 melanoma model. Notably, IMM20324 treatment resulted in the prevention of tumor growth following re-implantation of tumor cells, indicating the induction of immunological memory. Furthermore, exposure of IMM20324 correlated with decreased tumor volume and increased levels of intra-tumoral chemokines. Together, our data suggest that IL-38 is expressed in a high frequency of cancer patients and allows tumor cells to suppress anti-tumor immunity. Blockade of IL-38 activity using IMM20324 can re-activate immunostimulatory mechanisms in the tumor microenvironment leading to immune infiltration, the generation of tumor-specific memory and abrogation of tumor growth.

The role of IL-38 in intestinal diseases - its potential as a therapeutic target

IL-38, an anti-inflammatory cytokine, is a key regulator of homeostasis in host immunity. Intestinal immunity plays a critical role in defence against pathogenic invasion, as it is the largest surface organ and the most common entry point for micro-organisms. Dysregulated IL-38 activity is observed in several autoimmune diseases including systemic lupus erythematosus and atherosclerosis. The protective role of IL-38 is well illustrated in experimental colitis models, showing significantly worse colitis in IL-38 deficient mice, compared to wildtype mice. Moreover, exogenous IL-38 has been shown to ameliorate experimental colitis. Surprisingly, upregulated IL-38 is detected in inflamed tissue from inflammatory bowel disease patients, consistent with increased circulating cytokine levels, demonstrating the complex nature of host immunity in vivo. However, colonic IL-38 is significantly reduced in malignant tissues from patients with colorectal cancer (CRC), compared to adjacent non-cancerous tissue. Additionally, IL-38 expression in CRC correlates with 5-year survival, tumour size and differentiation, suggesting IL-38 plays a protective role during the development of CRC. IL-38 is also an independent biomarker for the prognosis of CRC, offering useful information in the management of CRC. Taken together, these data demonstrate the role of IL-38 in the maintenance of normal intestinal mucosal homeostasis, but that dysregulation of IL-38 contributes to initiation of chronic inflammatory bowel disease (resulting from persistent local inflammation), and that IL-38 provides protection during the development of colorectal cancer. Such data provide useful information for the development of novel therapeutic targets in the management of intestinal diseases for more precise medicine.

Serum levels of novel anti-inflammatory cytokine Interleukin-38 in diabetes patients infected with latent tuberculosis (DM-LTB-3)

IL-38 is a recently discovered, novel anti-inflammatory cytokine, which belongs to the IL-1β family. The role played by this cytokine in diabetes-tuberculosis nexus is not known. Serum levels of IL-38, TNF-α, IL-6, and IL-1β in Normal Glucose Tolerance (NGT) and chronic Diabetes (DM) subjects, both with and without latent tuberculosis (LTB) (n = 256) were quantified by ELISA. While, serum levels of IL-38 were significantly reduced, the levels of TNF-α, IL-6, and IL-1β were not altered, in LTB infected diabetes patients. While no significant secretion of IL-38 was detected in the quantiferon supernatant, secretion of TNF-α, IL-6, and IL-1β was significantly reduced in LTB infected diabetes patients. The decreased systemic levels of IL-38 and reduced in vitro secretion of other pro-inflammatory cytokines might represent a crucial pathway associated with diabetes-tuberculosis nexus.

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

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

Interleukin-36 Cytokines in Infectious and Non-Infectious Lung Diseases

The IL-36 family of cytokines were identified in the early 2000’s as a new subfamily of the IL-1 cytokine family, and since then, the role of IL-36 cytokines during various inflammatory processes has been characterized. While most of the research has focused on the role of these cytokines in autoimmune skin diseases such as psoriasis and dermatitis, recent studies have also shown the importance of IL-36 cytokines in the lung inflammatory response during infectious and non-infectious diseases. In this review, we discuss the biology of IL-36 cytokines in terms of how they are produced and activated, as well as their effects on myeloid and lymphoid cells during inflammation. We also discuss the role of these cytokines during lung infectious diseases caused by bacteria and influenza virus, as well as other inflammatory conditions in the lungs such as allergic asthma, lung fibrosis, chronic obstructive pulmonary disease, cystic fibrosis and cancer. Finally, we discuss the current therapeutic advances that target the IL-36 pathway and the possibility to extend these tools to treat lung inflammatory diseases.

Immunobiological Properties and Clinical Applications of Interleukin-38 for Immune-Mediated Disorders: A Systematic Review Study

Exponential growth in the usage of "cytokines" (as seroimmunobiomarkers) has facilitated more accurate prognosis, early diagnosis, novel, and efficient immunotherapeutics. Numerous studies have reported immunopathophysiological and immunopathological processes of interleukin-38 (IL-38). Therefore, in this systematic review article, the authors aimed to present an updated comprehensive overview on the immunobiological mechanisms, diagnostic, and immune gene-based therapeutic potentials of IL-38. According to our inclusion and exclusion criteria, a total of 216 articles were collected from several search engines and databases from the January 2012 to July 2021 time interval by using six main keywords. Physiologic or pathologic microenvironments, optimal dosage, and involved receptors affect the functionalities of IL-38. Alterations in serum levels of IL-38 play a major role in the immunopathogenesis of a wide array of immune-mediated disorders. IL-38 shows anti-inflammatory activities by reduction or inhibition of pro-inflammatory cytokines, supporting the therapeutic aspects of IL-38 in inflammatory autoimmune diseases. According to the importance of pre-clinical studies, it seems that manipulation of the immune system by immunomodulatory properties of IL-38 can increase the accuracy of diagnosis, and decipher optimal clinical outcomes. To promote our knowledge, more collaboration is highly recommended among laboratory scientists, internal/infectious diseases specialists, oncologists, immunologists, diseases-specific biomarkers scientists, and basic medical researchers.

Interleukin-38 Suppresses Cell Migration and Proliferation and Promotes Apoptosis of Colorectal Cancer Cell Through Negatively Regulating Extracellular Signal-Regulated Kinases Signaling

Inflammatory cytokines has been of great interest in the field of colorectal cancer (CRC) tumor immunology in recent years. As an anti-inflammatory interleukin (IL), IL-38 may contribute to the early diagnosis of CRC and improve the prognosis of CRC patients. This study was designed to investigate the role of circulating IL-38 and the regulatory mechanism of IL-38 in CRC. Expression of IL-38 were detected by ELISA and immunohistochemical staining. The influence of IL-38 on CRC were evaluated by Western blot and cell biology assays after CRC cells were treated by rhIL-38 or LM22B-10. We also verified the anti-tumor activity of IL-38 in transgenic mouse model. The expression of IL-38 was found to be correlated with progression of CRC. IL-38 inhibits CRC metastasis, proliferation and facilitates apoptosis through suppressing the activation of extracellular signal-regulated kinases (ERK) signaling pathway inducing the decrease of downstream genes, which were partially abrogated by ERK activator LM22B-10 in vitro. We also found that IL-38 overexpression inhibits tumorigenesis in vivo. Our findings indicate that IL-38 may serve as a serum prediction marker to identify the prognosis of CRC patients. IL-38 may inhibit the progression of CRC by negatively regulation on ERK signaling pathway.

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

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

IL-36 cytokines in inflammatory and malignant diseases: not the new kid on the block anymore

The IL-36 family of cytokines were first identified in 2000 based on their sequence homology to IL-1 cytokines. Over subsequent years, the ability of these cytokines to either agonise or antagonise an IL-1R homologue, now known as the IL-36 Receptor (IL-36R), was identified and these cytokines went through several cycles of renaming with the current nomenclature being proposed in 2010. Despite being identified over 20 years ago, it is only during the last decade that the function of these cytokines in health and disease has really begun to be appreciated, with both homeostatic functions in wound healing and response to infection, as well as pathological functions now ascribed. In the disease context, over activation of IL-36 has now been associated with many inflammatory diseases including Psoriasis and inflammatory bowel diseases, with roles in cancer also now being investigated. This review summarises the current knowledge of IL-36 biology, its role in inflammatory diseases and focuses on an emerging role for IL-36 in cancer.

Biology of interleukin-38 and its role in chronic inflammatory diseases

Interleukin (IL)-38 is the tenth member of the IL-1 cytokine family. IL-38 shares high similarity with IL-36Ra and IL-1Ra and can bind to their receptors, thus exerting an anti-inflammatory effect. Despite the lack of a signal peptide, IL-38 can be released from several cell types, but its maturation process remains obscure. The role of IL-38 in numerous inflammatory diseases, especially in autoimmune diseases, has been extensively studied. In this review, we discuss the characteristics, biological functions and pathways of IL-38, as well as its role in several chronic inflammatory diseases. Better understanding the role of IL-38 will pave the way for clinical treatments in the near future.

Interleukin-38 ameliorates poly(I:C) induced lung inflammation: therapeutic implications in respiratory viral infections

Interleukin-38 has recently been shown to have anti-inflammatory properties in lung inflammatory diseases. However, the effects of IL-38 in viral pneumonia remains unknown. In the present study, we demonstrate that circulating IL-38 concentrations together with IL-36α increased significantly in influenza and COVID-19 patients, and the level of IL-38 and IL-36α correlated negatively and positively with disease severity and inflammation, respectively. In the co-cultured human respiratory epithelial cells with macrophages to mimic lung microenvironment in vitro, IL-38 was able to alleviate inflammatory responses by inhibiting poly(I:C)-induced overproduction of pro-inflammatory cytokines and chemokines through intracellular STAT1, STAT3, p38 MAPK, ERK1/2, MEK, and NF-κB signaling pathways. Intriguingly, transcriptomic profiling revealed that IL-38 targeted genes were associated with the host innate immune response to virus. We also found that IL-38 counteracts the biological processes induced by IL-36α in the co-culture. Furthermore, the administration of recombinant IL-38 could mitigate poly I:C-induced lung injury, with reduced early accumulation of neutrophils and macrophages in bronchoalveolar lavage fluid, activation of lymphocytes, production of pro-inflammatory cytokines and chemokines and permeability of the alveolar-epithelial barrier. Taken together, our study indicates that IL-38 plays a crucial role in protection from exaggerated pulmonary inflammation during poly(I:C)-induced pneumonia, thereby providing the basis of a novel therapeutic target for respiratory viral infections.

Reduced concentrations of the B cell cytokine interleukin 38 are associated with cardiovascular disease risk in overweight subjects

The IL‐1 family member IL‐38 (IL1F10) suppresses inflammatory and autoimmune conditions. Here, we report that plasma concentrations of IL‐38 in 288 healthy Europeans correlate positively with circulating memory B cells and plasmablasts. IL‐38 correlated negatively with age (p = 0.02) and was stable in 48 subjects for 1 year. In comparison with primary keratinocytes, IL1F10 expression in CD19⁺ B cells from PBMC was lower, whereas cell‐associated IL‐38 expression was comparable. In vitro, IL‐38 is released from CD19⁺ B cells after stimulation with rituximab. Intravenous LPS in humans failed to induce circulating IL‐38, compared to 100‐fold induction of IL‐6 and IL‐1 receptor antagonist. In a cohort of 296 subjects with body mass index > 27 at high risk for cardiovascular disease, IL‐38 plasma concentrations were significantly lower than in healthy subjects (p < 0.0001), and lowest in those with metabolic syndrome (p < 0.05). IL‐38 also correlated inversely with high sensitivity C‐reactive protein (p < 0.01), IL‐6, IL‐1Ra, and leptin (p < 0.05). We conclude that a relative deficiency of the B cell product IL‐38 is associated with increased systemic inflammation in aging, cardiovascular and metabolic disease, and is consistent with IL‐38 as an anti‐inflammatory cytokine.

IL-36 family cytokines in protective versus destructive inflammation

The IL-1 family of cytokines and receptors are critical regulators of inflammation. Within the IL-1 family and in contrast to its IL-1 and IL-18 subfamilies, the IL-36 subfamily is still poorly characterized. Three pro-inflammatory agonists IL-36α, IL-36β, IL-36γ, one IL-36 receptor (IL-1R6) antagonist, IL-36RA, and one putative IL-1R6 antagonist, IL-38, have been grouped into the IL-36 cytokine subfamily. IL-36 agonists signal through a common receptor complex to serve as early triggers of inflammatory responses by activating and cross-regulating a number of inflammatory pathways including NF-κB, MAPK and IFN signaling. IL-36RA binds to IL-1R6 to limit inflammatory signaling, while IL-38 may be an antagonist of more than one IL-1 family receptor. Expression patterns of IL-36 family cytokines, being most prominently expressed in epithelial barrier tissues such as the skin and intestines as well as in immune cells, suggest a role in protecting these barriers from infection. Dysregulation of IL-36 family cytokine signaling at physiological barriers, most prominently the skin, induces autoimmune inflammation. However, transferring the potential of IL-36 to induce tissue damage to tumors might benefit cancer patients. Here we summarize signaling pathways regulated by IL-36 family cytokines, including IL-38, and the consequences for physiological protective and pathophysiological destructive inflammation. Moreover, we discuss the limits of current knowledge on IL-36 family function to open potential avenues for research in the future.

Interleukin-38 promotes tumor growth through regulation of CD8+ tumor-infiltrating lymphocytes in lung cancer tumor microenvironment

BACKGROUND

Interleukin (IL)-38 was discovered in 2001 and is a member of the IL-1 family of cytokines. IL-38 shows anti-inflammatory activity in several inflammatory diseases. In lung adenocarcinoma, we previously demonstrated that high IL-38 expression in tumor cells was associated with poor prognosis. However, the role of IL-38 in the tumor microenvironment has not been clarified.

METHODS

IL-38-plasmid-transfected Lewis lung carcinoma cells (LLC-IL38) and empty vector-transfected LLC cells (LLC-vector) were established. Cell proliferation in vitro and tumor growth in vivo were examined, and immunohistochemical staining was used to assess tumor-infiltrating lymphocytes (TILs). A CD8⁺ lymphocyte depletion model was established to show the association between IL-38 and CD8⁺ lymphocytes. Moreover, we examined the association between IL-38 expression and CD8⁺ TILs in human samples, analyzing immunohistochemical staining in 226 patients with radically resected lung adenocarcinoma.

RESULTS

Tumor growth of LLC-IL38 in vivo was significantly increased compared with that of LLC-vector, although cell proliferation of LLC-IL38 in vitro was lower than that of LLC-vector. CD8⁺ TILs were significantly decreased in LLC-IL38 tumor compared with LLC-vector tumor. The difference in tumor growth between LLC-IL38 and LLC-vector became insignificant after depletion of CD8⁺ lymphocytes. In immunohistochemical staining in tissues from patients with lung adenocarcinoma, multivariate analysis showed high IL-38 expression was an independent negative predicter of high density of CD8⁺ TILs.

CONCLUSION

We demonstrated that high IL-38 expression in tumor cells was significantly associated with reduction of CD8⁺ TILs and tumor progression. These results suggest that IL-38 could be a therapeutic target for lung cancer.

IL-34, IL-36 and IL-38 in colorectal cancer-key immunoregulators of carcinogenesis

Colorectal cancer (CRC) is still a big killer nowadays, but the precise underlying mechanism remains to be explored. It is believed that imbalance of host immunity in the local microenvironment plays a critical role in the tumorigenesis of CRC. IL-34 is inversely correlated with overall survival in CRC patients, perhaps via regulating terminal differentiation of a subset of macrophages (M2). It is believed that the recruitment/differentiation of M2 macrophages within the cancer simply represents an increase in number, but the function of these M2 macrophages may be compromised. IL-36s (IL-36α, β and γ) are constitutively expressed in non-cancer colon tissue, but colonic IL-36α, IL-36β and IL-36γ are substantially reduced in the CRC tissues (~ 80%). IL-36α is an independent factor affecting the survival of CRC patients. The level of IL-36α and/or IL-36γ in CRC tissue could potentially be used as biomarkers for predicting the prognosis of CRC at both the later or early stages of CRC. IL-38 is also an anti-inflammatory cytokine. Colonic IL-38 is ~ 95% lower in CRC compared to non-CRC colonic tissue, consistent with the positive correlation between differentiation of CRC, and colonic tumour expression of IL-38. IL-38 is a reliable/sensitive biomarker for distinguishing between CRC and non-cancer colonic tissue. There is a positive correlation between colonic IL-38 in CRC and prognosis and/or overall survival, particularly in advanced CRC, supporting IL-38 probably being a reliable and consistent independent factor in predicting the prognosis of CRC. The findings above may be useful in exploring therapeutic targeting for precision medicine.

Interleukin-38 in colorectal cancer: a potential role in precision medicine

Colorectal cancer (CRC) is a leading cause of cancer-related death, partly due to a lack of reliable biomarkers for early diagnosis. To improve the outcome of CRC, it is critical to provide diagnosis at an early stage using promising sensitive/specific marker(s). Using immunohistochemistry and histopathology, IL-38 expression was determined in tissue arrays of CRC with different TNM status and depth of tumour invasion. Data were compared to IL-38 in adjacent non-cancer tissue and correlated with demographic information, including survival. A substantial reduction of IL-38 was detected in the CRC tissue compared to adjacent non-cancer colonic tissue. IL-38 correlated with the extent of tumour differentiation (P < 0.0001); CRC location in the left side of the colon (P < 0.05), and smaller tumour size (≤ 5 cm; P < 0.05). Receiver operating characteristic (ROC) curve analysis demonstrated both high specificity and high sensitivity of IL-38 for the diagnosis of CRC [area under the curve (AUC) = 0.89)]. By sub-group analysis, AUC of IL-38 for the diagnosis of CRC was higher in poorly differentiated, right-sided CRC or tumour size > 5 cm (all AUC > 0.9). Significantly, longer survival was observed for the IL-38^high versus the IL-38^low groups in CRC patients (P = 0.04). Survival was also longer for IL-38^high patients with lymph node metastasis (P = 0.01) and TNM stage III-IV (P = 0.02). Multivariate analysis demonstrated that IL-38 (P = 0.05) and tumour invasion depth (P = 0.04) were independent factors for survival. High IL38 in CRC is an independent prognostic factor for the longer survival of CRC patients. IL-38 signalling may constitute a therapeutic target in CRC.

Interleukin 30 to Interleukin 40

Cytokines are important molecules that regulate the ontogeny and function of the immune system. They are small secreted proteins usually produced upon activation of cells of the immune system, including lymphocytes and myeloid cells. Many cytokines have been described, and several have been recognized as pivotal players in immune responses and in human disease. In fact, several anticytokine antibodies have proven effective therapeutics, especially in various autoimmune diseases. In the last 15 years, new cytokines have been described, and many remain poorly understood. Among the most recent cytokines discovered are interleukins-30 (IL-30) to IL-40. Several of these are members of other cytokine superfamilies, including several IL-1 superfamily members (IL-33, IL-36, IL-37, and IL-38) as well as several new members of the IL-12 family (IL-30, IL-35, and IL-39). The rest (IL-31, IL-32, IL-34, and IL-40) are encoded by genes that do not belong to any cytokine superfamily. Our aim of this review was to present a concise version of the information available on these novel cytokines to facilitate their understanding by members of the immunological community.

IL-38: A New Player in Inflammatory Autoimmune Disorders

Interleukin (IL)-38, a newly discovered IL-1 family cytokine, is expressed in several tissues and secreted by various cells. IL-38 has recently been reported to exert an anti-inflammatory function by binding to several receptors, including interleukin-36 receptor (IL-36R), interleukin-1 receptor accessory protein-like 1 (IL-1RAPL1), and interleukin-1 receptor 1 (IL-1R1) to block binding with other pro-inflammatory cytokines and inhibit subsequent signaling pathways; thereby regulating the differentiation and function of T cells, peripheral blood mononuclear cells, macrophages, and dendritic cells. Inflammatory autoimmune diseases, which are common immune-mediated inflammatory syndromes, are characterized by an imbalance between T helper cells (Ths), especially Th1s and Th17s, and regulatory T cells (Tregs). Recent findings have shown that abnormal expression of IL-38 in inflammatory autoimmune diseases, such as rheumatoid arthritis, psoriatic arthritis, systemic lupus erythematosus, primary Sjogren's syndrome, psoriasis, inflammatory bowel disease, hidradenitis suppurativa, ankylosing spondylitis, and glaucoma, involves Th1s, Th17s, and Tregs. In this review, the expression, regulation, and biological function of IL-38 are discussed, as are the roles of IL-38 in various inflammatory autoimmune disorders. Current data support that the IL-38/IL-36R and/or IL-38/IL-1RAPL1 axis primarily play an anti-inflammatory role in the development and resolution of inflammatory autoimmune diseases and indicate a possible therapeutic benefit of IL-38 in these diseases.

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.

Attenuated Airway Eosinophilic Inflammations in IL-38 Knockout Mouse Model

BACKGROUND

The role of IL-38, a new member of the IL-1 family, in airway eosinophilic inflammatory conditions such as asthma is unclear. To investigate the role of IL-38 in airway eosinophilic inflammation, an IL-38-gene deficient (KO) murine asthma model was analyzed.

METHODS

The numbers of eosinophils and neutrophils, and levels of IL-5, IL-13 and IL-17A protein and mRNA in bronchoalveolar lavage fluid (BALF) and lung tissue were compared between wild-type (WT) and IL-38-KO mice after OVA sensitization and challenge. The effects of additional purified recombinant mouse (rm) IL-38 protein were investigated in the IL-38-KO murine asthma model.

RESULTS

The IL-38 and IL-5 mRNA in WT mice was significantly higher after OVA challenge than after saline challenge (p<0.05). The number of airway eosinophils in IL-38-KO mice was significantly lower than in WT mice after OVA challenge (p<0.01). BALF analysis confirmed the lower number of airway eosinophils in IL-38-KO mice and showed that this was significantly associated with lower IL-5 protein levels (r=0.92, p<0.0001). However, the additional rm IL-38 protein did not neutralize airway eosinophilia in IL-38-KO mice.

CONCLUSION

IL-38 may enhance airway eosinophilic inflammation in asthma through IL-5 induction.

Is Interleukin-38 a key player cytokine in atherosclerosis immune gene therapy?

Atherosclerosis, a chronic inflammatory disease of the arteries associated with lipids and other metabolic alterations is a leading cause of death all around the world and its rate is raising as a result of unhealthy lifestyles. Reports by World Health Organization indicate that 31% of all death occurrences are due to heart attacks and strokes. Today, the most common medicines for treating atherosclerosis are statins which are HMG-coA reductase inhibitors. Beside their benefits in treating atherosclerosis, some side effects have been reported as well. Thus, therapeutic methods based on statins should be evaluated to result in more beneficial effects. Since atherosclerosis is an inflammatory disorder, an anti-inflammatory component can decrease the impact of this disease. Interleukin-38, a newly discovered anti-inflammatory cytokine, which acts as an Interleukin-36 receptor antagonist can block Nuclear Factor KB and Activator protein-1 signaling pathways, and block atherogenic core formation accordingly. This novel proposed immune gene therapy can be applied to atherosclerosis treatment in a trial study. In this hypothesis, Interleukin-38 gene is transferred into bone marrow Mesenchymal Stem Cells of atherosclerotic mouse model Apo E-/- via an adenoviral vector. It is expected that Interleukin-38 gene expression by Mesenchymal Stem Cells can efficiently remedy atherosclerosis without the side effects of statins.

Radiological Features of Programmed Cell Death-Ligand 2-positive Lung Adenocarcinoma: A Single-institution Retrospective Study

AIM

Programmed cell death-ligand 1 and 2 (PD-L1 and PD-L2) are ligands of the programmed cell death-1 (PD1) receptor. PD1/PD-L1 inhibitors have shown clinical efficacy in non-small cell lung cancer (NSCLC). However, relatively little is known about the expression of PD-L2, or its association with the clinicopathological features of NSCLC. Here, the radiological features of PD-L2-positive lung adenocarcinoma were evaluated.

MATERIALS AND METHODS

PD-L1 and PD-L2 expression were evaluated by immunohistochemical staining of surgically-resected specimens from 393 patients with primary lung adenocarcinoma who underwent preoperative thin-section computed tomography (CT), 222 of whom also underwent ¹⁸F-fluorodeoxyglucose positron-emission tomography/CT (¹⁸F-FDG-PET/CT).

RESULTS

Among the 393 specimens, 132 (33.6%) and 266 (67.7%) were positive for PD-L1 and PD-L2 expression, respectively. Multivariate analysis showed that the absence of surrounding ground glass opacity and the presence of air bronchogram were significantly associated with PD-L2 expression; however, there was no significant association between PD-L2 expression and the consolidation/tumor ratio. In 222 ¹⁸F-FDG-PET/CT, the maximum standardized uptake value was significantly higher in patients with PD-L2-positive compared to those with PD-L2-negative tumors.

CONCLUSION

PD-L2-positive lung adenocarcinomas are less radiologically malignant and invasive than their PD-L1-positive counterparts.

Reduced interleukin-38 in non-small cell lung cancer is associated with tumour progression

Lung cancer continues to be the leading cause of cancer-related deaths worldwide due to its high incidence, malignant behaviour and lack of major advancements in treatment strategy. The occurrence and development of lung cancer is closely related to inflammation. Thus, we conducted the present study to investigate the effects of IL-38 (interleukin-38), a newly identified anti-inflammatory factor, on non-small cell lung cancer (NSCLC), which accounts for about 85% of all lung cancers. We first evaluated the IL-38 expression in 384 pairs of NSCLC samples and their adjacent normal mucosa by real-time PCR, ELISA (enzyme-linked immunoassay) and tissue microarrays. Then the role of IL-38 on patient survival rates, cancer progression and their sensitivity to chemotherapy drugs was assessed. IL-38 was barely expressed in the NSCLC tissues but highly expressed in the adjacent normal tissues. The downregulation of IL-38 was significantly correlated with the results of the American Joint Committee on Cancer stage and degree of differentiation, and it was also shown to be an independent prognostic indicator of disease-free survival and overall survival for patients with NSCLC. Overexpression of IL-38 in NSCLC cells suppressed cell migration, invasion, proliferation and colony formation through suppressing β-catenin. IL-38 inhibited NSCLC formation in a mice model and sensitized the cancer cells to chemotherapy drugs. Our results show that IL-38 plays an inhibitory role in NSCLC development and functions as a novel prognostic indicator and a potential therapeutic target.

The enigmatic role of IL-38 in inflammatory diseases

IL-38 is the most recently discovered cytokine of the IL-1 family and is considered a potential inhibitor of the IL-1 and Toll-like receptor families. IL-38 exerts anti-inflammatory properties, especially on macrophages, by inhibiting secretion of pro-inflammatory cytokines, leading to reduced T-lymphocyte TH17 maturation. IL-38 has been studied most extensively in the context of chronic inflammatory diseases, particularly arthritis, where it is considered an attractive new drug candidate. IL-38 research has entered a new phase, with the realization that IL-38 is important in the pathophysiology of TH17 dependent-diseases (psoriasis, psoriatic arthritis and ankylosing spondylitis). In this review, we provide a critical evaluation of several controversial issues concerning IL-38 function and regulation. There is effectively contrasting data regarding IL-38: it is produced in conditions such as apoptosis, necrosis or inflammation, but data is lacking regarding IL-38 processing and biological function. Furthermore, the receptor for IL-38 has yet to be identified, although three candidate receptors - IL-1R1, IL-36R and IL-1RAPL1-have been proposed. Future studies will hopefully uncover new aspects of this enigmatic cytokine.