Interleukin 22-producing CD4+ T cells in malignant pleural effusion

IL-22: A key inflammatory mediator as a biomarker and potential therapeutic target for lung cancer

Lung cancer, one of the most prevalent cancers worldwide, stands as the primary cause of cancer-related deaths. As is well-known, the utmost crucial risk factor contributing to lung cancer is smoking. In recent years, remarkable progress has been made in treating lung cancer, particularly non-small cell lung cancer (NSCLC). Nevertheless, the absence of effective and accurate biomarkers for diagnosing and treating lung cancer remains a pressing issue. Interleukin 22 (IL-22) is a member of the IL-10 cytokine family. It exerts biological functions (including induction of proliferation and anti-apoptotic signaling pathways, enhancement of tissue regeneration and immunity defense) by binding to heterodimeric receptors containing type 1 receptor chain (R1) and type 2 receptor chain (R2). IL-22 has been identified as a pro-cancer factor since dysregulation of the IL-22-IL-22R system has been implicated in the development of different cancers, including lung, breast, gastric, pancreatic, and colon cancers. In this review, we discuss the differential expression, regulatory role, and potential clinical significance of IL-22 in lung cancer, while shedding light on innovative approaches for the future.

Immune modulation in malignant pleural effusion: from microenvironment to therapeutic implications

Immune microenvironment and immunotherapy have become the focus and frontier of tumor research, and the immune checkpoint inhibitors has provided novel strategies for tumor treatment. Malignant pleural effusion (MPE) is a common end-stage manifestation of lung cancer, malignant pleural mesothelioma and other thoracic malignancies, which is invasive and often accompanied by poor prognosis, affecting the quality of life of affected patients. Currently, clinical therapy for MPE is limited to pleural puncture, pleural fixation, catheter drainage, and other palliative therapies. Immunization is a new direction for rehabilitation and treatment of MPE. The effusion caused by cancer cells establishes its own immune microenvironment during its formation. Immune cells, cytokines, signal pathways of microenvironment affect the MPE progress and prognosis of patients. The interaction between them have been proved. The relevant studies were obtained through a systematic search of PubMed database according to keywords search method. Then through screening and sorting and reading full-text, 300 literatures were screened out. Exclude irrelevant and poor quality articles, 238 literatures were cited in the references. In this study, the mechanism of immune microenvironment affecting malignant pleural effusion was discussed from the perspectives of adaptive immune cells, innate immune cells, cytokines and molecular targets. Meanwhile, this study focused on the clinical value of microenvironmental components in the immunotherapy and prognosis of malignant pleural effusion.

Characterization of the alternative splicing landscape in lung adenocarcinoma reveals novel prognosis signature associated with B cells

BACKGROUND

Lung cancer is the second most commonly diagnosed cancer and the leading cause of cancer-related death. Malignant pleural effusion (MPE) is a special microenvironment for lung cancer metastasis. Alternative splicing, which is regulated by splicing factors, affects the expression of most genes and influences carcinogenesis and metastasis.

METHODS

mRNA-seq data and alternative splicing events in lung adenocarcinoma (LUAD) were obtained from The Cancer Genome Atlas (TCGA). A risk model was generated by Cox regression analyses and LASSO regression. Cell isolation and flow cytometry were used to identify B cells.

RESULTS

We systematically analyzed the splicing factors, alternative splicing events, clinical characteristics, and immunologic features of LUAD in the TCGA cohort. A risk signature based on 23 alternative splicing events was established and identified as an independent prognosis factor in LUAD. Among all patients, the risk signature showed a better prognostic value in metastatic patients. By single-sample gene set enrichment analysis, we found that among tumor-infiltrating lymphocytes, B cells were most significantly correlated to the risk score. Furthermore, we investigated the classification and function of B cells in MPE, a metastatic microenvironment of LUAD, and found that regulatory B cells might participate in the regulation of the immune microenvironment of MPE through antigen presentation and promotion of regulatory T cell differentiation.

CONCLUSIONS

We evaluated the prognostic value of alternative splicing events in LUAD and metastatic LUAD. We found that regulatory B cells had the function of antigen presentation, inhibited naïve T cells from differentiating into Th1 cells, and promoted Treg differentiation in LUAD patients with MPE.

Macrophage-derived exosome promotes regulatory T cell differentiation in malignant pleural effusion

Introduction

Tumor-associated macrophages are one of the key components of the tumor microenvironment. The immunomodulatory activity and function of macrophages in malignant pleural effusion (MPE), a special tumor metastasis microenvironment, have not been clearly defined.

Methods

MPE-based single-cell RNA sequencing data was used to characterize macrophages. Subsequently, the regulatory effect of macrophages and their secreted exosomes on T cells was verified by experiments. Next, miRNA microarray was used to analyze differentially expressed miRNAs in MPE and benign pleural effusion, and data from The Cancer Genome Atlas (TCGA) was used to evaluate the correlation between miRNAs and patient survival.

Results

Single-cell RNA sequencing data showed macrophages were mainly M2 polarized in MPE and had higher exosome secretion function compared with those in blood. We found that exosomes released from macrophages could promote the differentiation of naïve T cells into Treg cells in MPE. We detected differential expression miRNAs in macrophage-derived exosomes between MPE and benign pleural effusion by miRNA microarray and found that miR-4443 was significantly overexpressed in MPE exosomes. Gene functional enrichment analysis showed that the target genes of miR-4443 were involved in the regulation of protein kinase B signaling and lipid biosynthetic process.

Conclusions

Taken together, these results reveal that exosomes mediate the intercellular communication between macrophages and T cells, yielding an immunosuppressive environment for MPE. miR-4443 expressed by macrophages, but not total miR-4443, might serve as a prognostic marker in patients with metastatic lung cancer.

Th22 Cells/IL-22 Serves as a Protumor Regulator to Drive Poor Prognosis through the JAK-STAT3/MAPK/AKT Signaling Pathway in Non-Small-Cell Lung Cancer

The interaction of immune cells and cytokines in the tumor microenvironment affects the development and prognosis of tumors with an unclear potential regulatory mechanism. Recent studies have elucidated the protumor role of Th22 cells and its lineage-specific cytokine IL-22 in different human cancers. The present study is aimed at investigating the biological effect of Th22 cells/IL-22 and its molecular mechanism in the pathogenesis process of non-small-cell lung cancer (NSCLC). It was initially found that Th22 cells were enriched in the peripheral blood of NSCLC patients. The level of Th22 cells in peripheral blood mononuclear cells (PBMCs) was positively correlated with the TNM stage, lymph node metastasis, and clinical tumor biomarkers. Furthermore, IL-22 not only antagonized the apoptosis inducing and cell cycle arresting effect by chemotherapy and molecular targeted drugs on NSCLC cell lines but also promoted tumor cell proliferation and tumor tissue growth. Moreover, IL-22 activated the JAK-STAT3/MAPK/AKT signaling pathway, both in vitro and in vivo. Conclusively, the present results confirm that Th22 cells/IL-22 may serve as a negative immune regulator in lung cancer.

Th17 cells and their related cytokines: vital players in progression of malignant pleural effusion

Malignant pleural effusion (MPE) is an exudative effusion caused by primary or metastatic pleural carcinosis. Th17 cells and their cytokines are critical components in various disease including MPE. In this review, we summarize current published articles regarding the multifunctional roles of Th17 cells and their related cytokines in MPE. Th17 cells are accumulated in MPE compared with paired serum via certain manners. The upregulation of Th17 cells and the interactions between Th17 cells and other immune cells, such as Th1 cells, Th9 cells, regulatory T cells and B cells, are reported to be involved in the formation and development of MPE. In addition, cytokines, which are elaborated by Th17 cells, including IL-17A, IL-17F, IL-21, IL-22, IL-26, GM-CSF, or associated with Th17 cells differentiation, including IL-1β, IL-6, IL-23, TGF-β, are linked to the pathogenesis of MPE through exerting pro- or anti-tumorigenic functions on their own as well as regulating the generation and differentiation of Th17 cells in MPE. Based on these findings, we proposed that Th17 cells and their cytokines might be diagnostic or prognostic tools and potential therapeutic targets for MPE.

Recruitment of IL-1β-producing intermediate monocytes enhanced by C5a contributes to the development of malignant pleural effusion

Background

Monocytes are involved in tumor growth and metastasis, but the distribution of monocyte phenotypes and their role in the development of malignant pleural effusion (MPE) remains unknown.

Methods

A total of 94 MPE patients (76 diagnosed with adenocarcinoma lung cancer and 18 with squamous cell lung cancer) and 102 volunteers for health examination in Xiangya Hospital from December 2016 to December 2019 were included in the study.

Results

The distribution of monocyte subtypes identified by the expression of CD14 and CD16 were analyzed by flow cytometry. The proportion of CD14⁺⁺CD16⁺ intermediate monocytes were significantly increased in pleural effusion of MPE patients. The complement system components were assayed by immunohistochemistry and ELISA, and higher expression of the classical and alternative pathways were detected in malignant pleural tissue. Transwell assay further revealed that C5a enhanced the infiltration of intermediate monocytes into the pleural cavity by promoting CCL2 production in pleural mesothelial cells (PMCs). In addition, C5a promoted the secretion of IL‐1β by intermediate monocytes. Furthermore, C5a activated in intermediate monocytes and IL‐1β released after C5a stimulation by monocytes promoted the proliferation, migration, adhesion, and epithelial‐to‐mesenchymal transition (EMT) of tumor cells, and attenuated tumor cell apoptosis.

Conclusions

C5a, activated by the classical and alternative pathways of the complement system, not only mediated the infiltration of intermediate monocytes by enhancing CCL2 production in PMCs but also induced IL‐1β release from the recruited monocytes in MPE. The consequence of C5a activation and the subsequent IL‐1β overexpression in intermediate monocytes contributed to MPE progression.

T Helper Cell Subsets in the Pleural Fluid of Tuberculous Patients Differentiate Patients With Non-Tuberculous Pleural Effusions

Background

Tuberculous pleural effusion (TPE) is one of the most common forms of extrapulmonary tuberculosis (Tb). Patients with TPE or malignant pleural effusions (MPE) frequently have a similar lymphocytic pleural fluid profile. Since the etiology of PE in various diseases is different, identifying the cellular components may provide diagnostic clues for understanding the pathogenesis.

Objective

We determined the frequency of T helper (Th) subtypes in the PEs for differentiation of Tb and non-Tb patients.

Methods

Thirty patients with TPE, 30 patients with MPE, 14 patients with empyema (EMP), and 14 patients with parapneumonic effusion (PPE) were enrolled between December 2018 and December 2019. Five-milliliter fresh PE in tubes containing heparin as an anticoagulant was obtained from patients. The frequencies of CD4+IL-9+, CD4+IL-22+, CD+IL-17+, and regulatory T-cells CD4+CD25+ FOXP3+ (Treg) were determined by flow cytometry.

Results

Treg cells have a lower frequency in TPE patients [4.2 (0.362-17.24)] compared with non-TPE patients [26.3 (3.349-76.93, p < 0.0001)]. The frequency of CD4+IL-9+ cells was significantly lower in TPE patients [3.67 (0.87-47.83)] compared with non-TPE groups [13.05 (1.67-61.45), p < 0.0001]. On the contrary, there was no significant difference in the frequency of CD4+IL-17+ and CD4+IL-22+ cells between TPE and non-TPE patients (p = 0.906 and p = 0.2188). Receiver-operator curve (ROC) analysis demonstrated that CD4+CD25+FOXP3+ T cells [optimal cutoff value = 13.6 (%), sensitivity 90%, specificity 75.86%] could be considered as predictor for TPE. However, adenosine deaminase [cutoff value 27.5 (IU/l), sensitivity 90%, specificity 96.5%] levels had an even greater predictive capacity.

Conclusion

ADA, Treg cells, and CD4+IL-9+ cells may differentiate TPE from non-TPE patients. However, these results need validation in an independent large cohort.

Single-cell analysis of diverse immune phenotypes in malignant pleural effusion

The complex interactions among different immune cells have important functions in the development of malignant pleural effusion (MPE). Here we perform single-cell RNA sequencing on 62,382 cells from MPE patients induced by non-small cell lung cancer to describe the composition, lineage, and functional states of infiltrating immune cells in MPE. Immune cells in MPE display a number of transcriptional signatures enriched for regulatory T cells, B cells, macrophages, and dendritic cells compared to corresponding counterparts in blood. Helper T, cytotoxic T, regulatory T, and T follicular helper cells express multiple immune checkpoints or costimulatory molecules. Cell-cell interaction analysis identifies regulatory B cells with more interactions with CD4⁺ T cells compared to CD8⁺ T cells. Macrophages are transcriptionally heterogeneous and conform to M2 polarization characteristics. In addition, immune cells in MPE show the general up-regulation of glycolytic pathways associated with the hypoxic microenvironment. These findings show a detailed atlas of immune cells in human MPE and enhance the understanding of potential diagnostic and therapeutic targets in advanced non-small cell lung cancer.

IL-26 promotes the pathogenesis of malignant pleural effusion by enhancing CD4+ IL-22+ T-cell differentiation and inhibiting CD8+ T-cell cytotoxicity

IL-26 is a newly discovered IL-10 cytokine family member mainly secreted by Th17 cells. However, the relationship between IL-26 and lung cancer remains unclear. The present study reported that IL-26 is involved in the production and promotion of malignant pleural effusion (MPE) for the first time. The concentrations of IL-26 and several Th17-related cytokines in MPE and peripheral blood (PB) from MPE patients were measured. IL-26, IL-10, and IL-6 were elevated in MPE compared to PB. The cell resource of IL-26 was primary Th17 cells measured by flow cytometry, whereas Tc17 cells and macrophages could also contribute to higher concentration of IL-26 in MPE. Abundant IL-6 and IL-23 in MPE could promote the frequency of IL-26 expressed by CD4+ T cells through phosphorylating STAT3 signaling pathway and promoting the expression of a specific Th17 lineage marker RORγt subsequently. IL-26 could selectively increase Th22 proportion through up-regulating the percentage of Ki-67 expressed by CD4+ T cells and the expression of IL-22 secreted by memory CD4+ T cells. In addition, IL-26 could decrease secretion of granzyme B. The tumor-killing activity of CD8+ T cells were inhibited as well when cocultured with malignant cells. Furthermore, the accumulation of IL-26 protein in MPE predicted poor patient survival. In summary, our results indicated that IL-26 was involved in the pathogenesis of MPE by exerting its impacts on both CD4+ T cells and CD8+ T cells.

Malignant Pleural Effusions-A Window Into Local Anti-Tumor T Cell Immunity?

The success of immunotherapy that targets inhibitory T cell receptors for the treatment of multiple cancers has seen the anti-tumor immune response re-emerge as a promising biomarker of response to therapy. Longitudinal characterization of T cells in the tumor microenvironment (TME) helps us understand how to promote effective anti-tumor immunity. However, serial analyses at the tumor site are rarely feasible in clinical practice. Malignant pleural effusions (MPE) associated with thoracic cancers are an abnormal accumulation of fluid in the pleural space that is routinely drained for patient symptom control. This fluid contains tumor cells and immune cells, including lymphocytes, macrophages and dendritic cells, providing a window into the local tumor microenvironment. Recurrent MPE is common, and provides an opportunity for longitudinal analysis of the tumor site in a clinical setting. Here, we review the phenotype of MPE-derived T cells, comparing them to tumor and blood T cells. We discuss the benefits and limitations of their use as potential dynamic biomarkers of response to therapy.

Helper T cells in malignant pleural effusion

Malignant pleural effusion (MPE) is a frequent complication of malignancies and poses a clinical problem. CD4⁺ T lymphocytes are the most frequent cell population in MPE. Traditionally, CD4⁺ T cells are classified into two subsets based on cytokine production profiles, type 1 (Th1) and type 2 (Th2) helper T cells, which exhibit distinct functions. Recently, other T-cell subsets have been added to the Th-cell "portfolio", including regulatory T, Th17, Th9, and Th22 cells. The current review focuses on summarizing the Th-cell phenotypic characteristics, mechanism of Th-cell differentiation, and their pleural space recruitment, based on recent research. We also describe the interplay in MPE among different Th cells, as well as Th cells and lung cancer cells or mesothelial cells. Future research should expand the landscape map of human MPE immune cells, explore the immuno-regulation of B cells, and investigate the communication between macrophages and Th cells in MPE, which may facilitate meaningful advancements in the diagnoses and therapeutics of MPE.

A Double Edged Sword Role of Interleukin-22 in Wound Healing and Tissue Regeneration

Wound healing and tissue regeneration is an intricate biological process that involves repair of cellular damage and maintenance of tissue integrity. Cascades involved in wound healing and tissue regeneration highly overlap with cancer causing pathways. Usually, subsequent tissue damage events include release of a number of cytokines to accomplish post-trauma restoration. IL-22 is one of the cytokines that are immediately produced to initiate immune response against several tissue impairments. IL-22 is a fundamental mediator in inflammation, mucous production, protective role against pathogens, wound healing, and tissue regeneration. However, accumulating evidence suggests pivotal role of IL-22 in instigation of various cancers due to its pro-inflammatory and tissue repairing activity. In this review, we summarize how healing effects of IL-22, when executed in an uncontrollable fashion can lead to carcinogenesis.

IL-17A-Producing γδT Cells Inhibit the Formation of Malignant Pleural Effusions

γδT cells are an important source of IL-17A and play an anti- or protumor role depending on the surrounding microenvironment. The precise role of γδT cells in the development of malignant pleural effusions (MPE) remains unknown. Using flow cytometry, we analyzed the distribution and differentiation of γδT cells in wild-type (WT) and IL-10^-∕- mice. We carefully elucidated the influence of γδT cells on the formation of MPE by depleting γδT cells from WT, IL-10^-∕-, and IL-17a^-∕- mice. The distribution of γδT17 cells in human MPE and peripheral blood was also determined. Our data showed that both γδT cells and IL-17A-producing γδT (γδT17) cells accumulated in murine MPE, and IL-10 deficiency enhanced their accumulation. γδT cells were the main source of IL-17A in MPE for both WT and IL-10^-∕- mice. IL-10 inhibited the chemotactic response of γδT cells to MPE and the proliferation of these cells. IL-10 suppressed γδT cell secretion of IL-17A via RORγt. The ablation of γδT cells accelerated MPE accumulation in both WT and IL-10^-∕- mice, but it did not influence MPE accumulation in IL-17a^-∕- mice. Patients with higher frequencies of γδT17 cells had significantly longer survival times than patients with lower frequencies of γδT17 cells. Taken together, our data demonstrate that γδT17 cells play an inhibitory role in the progression of MPE, and the accumulation of γδT17 cells in MPE is suppressed by IL-10.

Multiplexed molecular profiling of lung cancer with malignant pleural effusion using next generation sequencing in Chinese patients

Lung cancer is the most common type of cancer and the leading cause of cancer-associated death worldwide. Malignant pleural effusion (MPE), which is observed in ~50% of advanced non-small cell lung cancer (NSCLC) cases, and most frequently in lung adenocarcinoma, is a common complication of stage III-IV NSCLC, and it can be used to predict a poor prognosis. In the present study, multiple oncogene mutations were detected, including 17 genes closely associated with initiation of advanced lung cancer, in 108 MPE samples using next generation sequencing (NGS). The NGS data of the present study had broader coverage, deeper sequencing depth and higher capture efficiency compared with NGS findings of previous studies on MPE. In the present study, using NGS, it was demonstrated that 93 patients (86%) harbored EGFR mutations and 62 patients possessed mutations in EGFR exons 18-21, which are targets of available treatment agents. EGFR L858R and exon 19 indel mutations were the most frequently observed alterations, with frequencies of 31 and 25%, respectively. In 1 patient, an EGFR amplification was identified and 6 patients possessed a T790M mutation. ALK + EML4 gene fusions were identified in 6 patients, a ROS1 + CD74 gene fusion was detected in 1 patient and 10 patients possessed a BIM (also known as BCL2L11) 2,903-bp intron deletion. In 4 patients, significant KRAS mutations (G12D, G12S, G13C and A146T) were observed, which are associated with resistance to afatinib, icotinib, erlotinib and gefitinib. There were 83 patients with ERBB2 mutations, but only two of these mutations were targets of available treatments. The results of the present study indicate that MPE is a reliable specimen for NGS based detection of somatic mutations.

Interleukin-22 Mediates the Chemotactic Migration of Breast Cancer Cells and Macrophage Infiltration of the Bone Microenvironment by Potentiating S1P/SIPR Signaling

The interleukin-22 (IL-22) signaling pathway is well known to be involved in the progression of various cancer types but its role in bone metastatic breast cancer remains unclear. We demonstrate using human GEO profiling that bone metastatic breast cancer displays elevated interleukin-22 receptor 1 (IL-22R1) and sphingosine-1-phosphate receptor 1 (S1PR1) expression. Importantly, IL-22 stimuli promoted the expression of IL-22R1 and S1PR1 in aggressive MDA-MB-231 breast cancer cells. IL-22 treatment also increased sphingosine-1-phosphate production in mesenchymal stem cells (MSCs) and induced the sphingosine-1-phosphate (S1P)-mediated chemotactic migration of MDA-MB-231 cells. This effect was inhibited by an S1P antagonist. In addition to the S1PR1 axis, IL-22 stimulated the expression of matrix metalloproteinase-9 (MMP-9), thereby promoting breast cancer cell invasion. Moreover, IL-22 induced IL22R1 and S1PR1 expression in macrophages, myeloid cell, and MCP1 expression in MSCs to facilitate macrophage infiltration. Immunohistochemistry indicated that IL-22R1 and S1PR1 are overexpressed in invasive malignant breast cancers and that this correlates with the MMP-9 levels. Collectively, our present results indicate a potential role of IL-22 in driving the metastasis of breast cancers into the bone microenvironment through the IL22R1-S1PR1 axis.

Janus or Hydra: The Many Faces of T Helper Cells in the Human Tumour Microenvironment

CD4+ T helper (T_H) cells are key regulators in the tumour immune microenvironment (TIME), mediating the adaptive immunological response towards cancer, mainly through the activation of cytotoxic CD8+ T cells. After antigen recognition and proper co-stimulation, naïve T_H cells are activated, undergo clonal expansion, and release cytokines that will define the differentiation of a specific effector T_H cell subtype. These different subtypes have different functions, which can mediate both anti- and pro-tumour immunological responses. Here, we present the dual role of T_H cells restraining or promoting the tumour, the factors controlling their homing and differentiation in the TIME, their influence on immunotherapy, and their use as prognostic indicators.

Lung Cancer Heterogeneity in Modulation of Th17/IL17A Responses

The interplay between tumors and their immune microenvironment is critical for cancer development and progression. The discovery of tumor heterogeneity has provided a window into a complex interplay between tumors, their secreted products, and host immune responses at the cellular and molecular levels. Tumor heterogeneity can also act as a driving force in promoting treatment resistance and correlates with distinct tumor-mediated acquired immune responses. A prevailing question is how genetic aberrations in solid tumors can shape the immune landscape, resulting in pro-tumor or anti-tumor activities. Here we review evidence for clinical and pathophysiological mechanisms that underlie different types of non-small cell lung cancer (NSCLC) and provide new insights for future immunomodulatory-based therapies. Some of the more common driver mutations in NSCLC heterogeneity includes the opposing immune responses in oncogenic mutations in K-ras vs. non-K-ras models and their pro-inflammatory cytokines such as interleukin (IL)17A. We will discuss possible molecular and metabolic mechanisms that may govern the opposing immune responses observed in distinct genetic models of NSCLCs. A deeper understanding of how tumor heterogeneity modulates immune response can improve current therapeutic strategies and provide precise treatment to individual lung cancer patients.

IL-22 Confers EGFR-TKI Resistance in NSCLC via the AKT and ERK Signaling Pathways

Background: The efficacy of an EGFR-targeted treatment strategy for non-small cell lung cancer (NSCLC) is reduced by drug resistance. IL-22 enhances tumor growth and induces chemotherapy resistance in human lung cancer cells. The present study elucidated the IL-22-induced mechanism underlying EGFR-tyrosine kinase inhibitor (TKI) resistance in NSCLC.

Methods: The plasma and tissues of patients who received EGFR-TKIs were utilized to determine the association between IL-22 expression and gefitinib efficacy. The IL-22 effect on the EGFR/ERK/AKT pathways in NSCLC HCC827 and PC-9 cells was determined using the CCK-8 assay, western blot, and flow cytometric analysis. A PC-9 xenograft model of IL-22 exposure was established. Gefitinib was administered to mice in combination with IL-22 or vehicle.

Results: We showed that IL-22 expression was higher in the EGFR-TKI-resistant group compared to EGFR-TKI-sensitive group. IL-22 expression was associated with EGFR-TKI efficacy in plasma. Additional treatment of IL-22 induced gefitinib resistance and reduced apoptosis in PC-9 and HCC827 cell lines. Furthermore, we showed that the effects of IL-22 attributed to p-ERK, p-EGFR, and p-AKT up-regulation. IL-22 neutralizing antibody completely abrogated the effects of IL-22 on apoptosis and AKT/EGFR/ERK signaling. Finally, we showed that IL-22 enhanced tumor growth and induced gefitinib resistance in the PC-9 xenograft model. Moreover, compared with gefitinib alone, the combination of IL-22 and gefitinib led to an increase in Ki67-positive staining and a reduction in TUNEL staining.

Conclusions: Our findings indicate that IL-22 plays a role in tumor progression and EGFR-TKI resistance in NSCLC. Thus, IL-22 might serve as a novel biomarker to overcome resistance of EGFR-TKI.

Progression or suppression: Two sides of the innate lymphoid cells in cancer

Innate lymphoid cells (ILCs) as key players in innate immunity have been shown to be significantly associated with inflammation, lymphoid neogenesis, tissue remodeling, mucosal immunity and lately have been considered a remarkable nominee for either tumor-promoting or tumor-inhibiting functions. This dual role of ILCs, which is driven by intrinsic and extrinsic factors like plasticity of ILCs and the tumor microenvironment, respectively, has aroused interest in ILCs subsets in past decade. So far, numerous studies in the cancer field have revealed ILCs to be key players in the initiation, progression and inhibition of tumors, therefore providing valuable insights into therapeutic approaches to utilize the immune system against cancer. Herein, the most recent achievements regarding ILCs subsets including new classifications, their transcription factors, markers, cytokine release and mechanisms that led to either progression or inhibition of many tumors have been evaluated. Additionally, the available data regarding ILCs in most prevalent cancers and new therapeutic approaches are summarized.

IL-10 promotes malignant pleural effusion in mice by regulating TH 1- and TH 17-cell differentiation and migration

The role of IL-10 in malignant pleural effusion (MPE) remains unknown. By using murine MPE models, we observed that an increase in pleural IL-10 was a significant predictor of increased risk of death. We noted that T_H 1- and T_H 17-cell content in MPE was higher in IL-10^-/- mice than in WT mice, and IL-10 deficiency promoted differentiation into T_H 1 but not into T_H 17 cells. A higher fraction of T_H 1 and T_H 17 cells in the MPE of IL-10^-/- mice expressed CXCR3 compared with WT mice. We also demonstrated that Lewis lung cancer and colon adenocarcinoma cells secreted large amounts of CXCL10, a ligand of CXCR3, which induced the migration of T_H 1 and T_H 17 cells into the MPE, and IFN-γ could promote this signaling cascade. Furthermore, intrapleural injection of mice with CXCL10-deficient tumor cells led to decreased T_H 1- and T_H 17-cell content in MPE, increased MPE volume, and reduced survival of MPE-bearing mice. Taken together, we demonstrated that IL-10 deficiency promoted T-cell differentiation into T_H 1 cells and upregulated the CXCR3-CXCL10 signaling pathway that recruits T_H 1 and T_H 17 cells into MPE, ultimately resulting in decreased MPE formation and longer survival time of mice-bearing MPE.

Microarray expression profile and analysis of circular RNA regulatory network in malignant pleural effusion

Malignant pleural effusion (MPE) is a common complication of lung cancer. Accumulating evidence has suggested that circular RNAs (circRNAs) play important roles in oncogenesis and progression of cancer. However, the expression pattern of circRNAs in MPE remains largely unknown and awaits investigation. The study was designed to elucidate the potential roles of differentially expressed circRNAs in MPE. Herein, we detected a total of 1350 differentially expressed circRNAs and 1727 differentially expressed mRNAs in lung adenocarcinoma-associated malignant pleural effusion (LA-MPE) compared with tuberculous pleural effusion (TPE) by Clariom D Human Microarray. Among the top 5 up-regulated circRNAs (hsa_circ_0067705, hsa_circ_0025542, hsa_circ_0072793, hsa_circ_0084927, and hsa_circ_0085386), four were verified significantly up-regulated in LA-MPE by qRT-PCR and hsa_circ_0085386 had an increasing trend. CircRNA-miRNA-mRNA network for the top 5 up-regulated circRNAs was constructed and pathway analysis indicated that the enriched mRNA targets involved in PI3K-Akt signaling pathway, Axon guidance, Regulation of actin cytoskeleton and Rap1 signaling pathway were potentially regulated by these aberrantly expressed circRNAs. We generated specific circRNA profiles in LA-MPE for the first time. And analysis of circRNA regulatory network could provide evidence that circRNAs are important in MPE development because they participate in cancer-related pathways by sequestering miRNAs. Our findings suggested that aberrantly expressed circRNAs may be involved in the development of LA-MPE.

Activated naïve B cells promote development of malignant pleural effusion by differential regulation of TH1 and TH17 response

Inflammatory signaling networks between tumor cells and immune cells contribute to the development of malignant pleural effusion (MPE). B cells have been found in MPE; however, little is known about their roles there. In the present study, by using mouse MPE models, we noted that although the total B cells in MPE were decreased as compared with the corresponding blood and spleen, the percentage of activated naïve B cells expressing higher levels of CD80, CD86, myosin heavy chain-II, CD44, CD69, and programmed cell death-ligand 1 (PD-L1) molecules were increased in wild-type mouse MPE. Compared with wild-type mice, decreased T helper (T_H)1 cells and increased T_H17 cells were present in B cell-deficient mouse MPE, which paralleled to the reduced MPE volume and longer survival time. Adoptive transfer of activated naïve B cells into B cell-deficient mice was able to increase T_H1 cells and decrease T_H17 cells in MPE and shorten the survival of mice bearing MPE. Furthermore, we demonstrated that activated naïve B cells inhibited T_H17-cell expansion via the PD-1/PD-L1 pathway and promoted naïve CD4⁺ T-cell differentiation into T_H1/T_H17 cells through secreting IL-27/IL-6 independent of the PD-1/PD-L1 pathway. Collectively, our data uncovered a mechanism by which naïve B cells promote MPE formation by regulating T_H1/T_H17 cell responses, making these B cells an attractive target for therapeutic intervention in the fight against cancer.

Targeting interleukin-22 for cancer therapy

Interleukin-22 (IL-22) is a member of IL-10 family of cytokines. IL-22 induces proliferative and anti-apoptotic signaling pathways and production of anti-microbial molecules that enhance tissue regeneration and host defense. IL-22 has also been identified as a cancer-promoting cytokine since deregulation of the IL-22-IL-22R1 system is linked to different cancer entities including lung, breast, gastric, pancreatic and colon cancers. T cells and innate lymphoid cells are the main cellular sources of IL-22. Expression of its specific receptor IL-22R1 is restricted to the non-hematopoietic cells which makes the IL-22-IL-22R1 pathway an attractive target for anti-cancer therapy. For development of such therapies, a better understanding of IL-22 regulation in the tumor microenvironment is needed. We could recently decipher how cancer cells promote IL-22 production by memory T cells via induction of IL-1. Here we will discuss how this knowledge might contribute to developing therapies disregulating the IL-22 pathway for cancer immunotherapy.

Ambiguous roles of innate lymphoid cells in chronic development of liver diseases

Innate lymphoid cells (ILCs) are defined as a distinct arm of innate immunity. According to their profile of secreted cytokines and lineage-specific transcriptional factors, ILCs can be categorized into the following three groups: group 1 ILCs (including natural killer (NK) cells and ILC1s) are dependent on T-bet and can produce interferon-γ; group 2 ILCs (ILC2s) are dependent on GATA3 and can produce type 2 cytokines, including interleukin (IL)-5 and IL-13; and, group 3 ILCs (including lymphoid tissue-like cells and ILC3s) are dependent on RORγt and can produce IL-22 and IL-17. Collaborative with adaptive immunity, ILCs are highly reactive innate effectors that promptly orchestrate immunity, inflammation and tissue repair. Dysregulation of ILCs might result in inflammatory disorders. Evidence regarding the function of intrahepatic ILCs is emerging from longitudinal studies of inflammatory liver diseases wherein they exert both physiological and pathological functions, including immune homeostasis, defenses and surveillance. Their overall effect on the liver depends on the balance of their proinflammatory and antiinflammatory populations, specific microenvironment and stages of immune responses. Here, we review the current data about ILCs in chronic liver disease progression, to reveal their roles in different stages as well as to discuss their therapeutic potency as intervention targets.

Cancer cells induce interleukin-22 production from memory CD4+ T cells via interleukin-1 to promote tumor growth

IL-22 has been identified as a cancer-promoting cytokine that is secreted by infiltrating immune cells in several cancer models. We hypothesized that IL-22 regulation would occur at the interface between cancer cells and immune cells. Breast and lung cancer cells of murine and human origin induced IL-22 production from memory CD4+ T cells. In the present study, we found that IL-22 production in humans is dependent on activation of the NLRP3 inflammasome with the subsequent release of IL-1β from both myeloid and T cells. IL-1 receptor signaling via the transcription factors AhR and RORγt in T cells was necessary and sufficient for IL-22 production. In these settings, IL-1 induced IL-22 production from a mixed T helper cell population comprised of Th1, Th17, and Th22 cells, which was abrogated by the addition of anakinra. We confirmed these findings in vitro and in vivo in two murine tumor models, in primary human breast and lung cancer cells, and in deposited expression data. Relevant to ongoing clinical trials in breast cancer, we demonstrate here that the IL-1 receptor antagonist anakinra abrogates IL-22 production and reduces tumor growth in a murine breast cancer model. Thus, we describe here a previously unrecognized mechanism by which cancer cells induce IL-22 production from memory CD4+ T cells via activation of the NLRP3 inflammasome and the release of IL-1β to promote tumor growth. These findings may provide the basis for therapeutic interventions that affect IL-22 production by targeting IL-1 activity.

Elevated Th22 cells and related cytokines in patients with epithelial ovarian cancer

This study is conducted to investigate the involvement of T-helper (Th) cells and regulatory T cells in epithelial ovarian cancer (EOC).The percentages of Th22, Th17, Th1, and regulatory T cells in the peripheral blood of EOC patients, benign ovarian epithelial neoplasm (BOEN) patients, and healthy control (HC) were examined by flow cytometry. Enzyme-linked immunosorbent assay was used to determine serum levels of interleukin (IL)-22, IL-17, interferon-γ (IFN-γ), and tumor necrosis factor-α (TNF-α).Th22 and Th17 were significantly increased in EOC patients. The plasma concentrations of IL-22 and TNF-α were significantly elevated in EOC patients compared with BOEN patients and HC. In EOC patients, there was an increased trend of Th22, IL-22, and TNF-α in stage III-IV patients compared with stage I-II patients. A positive correlation was seen among Th22, Th17, and Th1 cells in EOC patients. Similarly, positive correlations were detected between Th22 cells and IL-22 or TNF-α and between Th1 cells and interferon-γ (IFN-γ) in EOC patients. Besides, no significant difference was found in Th1 cells and regulatory T cells among EOC and BOEN patients and HC.There is a higher circulating frequency of Th22, Th17 cells, IL-22, and TNF-α concentration in EOC patients, which may conjointly participate in the pathogenesis and growth of EOC.

Inflammatory and Anti-Inflammatory Equilibrium, Proliferative and Antiproliferative Balance: The Role of Cytokines in Multiple Myeloma

Multiple myeloma (MM) is typically exemplified by a desynchronized cytokine system with increased levels of inflammatory cytokines. We focused on the contrast between inflammatory and anti-inflammatory systems by assessing the role of cytokines and their influence on MM. The aim of this review is to summarize the available information to date concerning this equilibrium to provide an overview of the research exploring the roles of serum cytokines in MM. However, the association between MM and inflammatory cytokines appears to be inadequate, and other functions, such as pro-proliferative or antiproliferative effects, can assume the role of cytokines in the genesis and progression of MM. It is possible that inflammation, when guided by cancer-specific Th1 cells, may inhibit tumour onset and progression. In a Th1 microenvironment, proinflammatory cytokines (e.g., IL-6 and IL-1) may contribute to tumour eradication by attracting leucocytes from the circulation and by increasing CD4 ⁺ T cell activity. Hence, caution should be used when considering therapies that target factors with pro- or anti-inflammatory activity. Drugs that may reduce the tumour-suppressive Th1-driven inflammatory immune response should be avoided. A better understanding of the relationship between inflammation and myeloma will ensure more effective therapeutic interventions.

Immune Regulation of Toll-Like Receptor 2 Engagement on CD4+ T Cells in Murine Models of Malignant Pleural Effusion

Toll-like receptor (TLR) 2 has a well-known role in sensing multiple ligands that include microbial products, endotoxin, and some extracellular matrix molecules; however, its role in the development of malignant pleural effusion (MPE) remains unknown. We performed the present study to explore the impact of TLR2 signaling on the development of MPE and to define the underlying mechanisms by which TLR2 works. Development of MPE was compared between TLR2^-/- and wild-type (WT) mice. The effect of TLR2 on differentiation of T helper type 17 (Th17), Th9, and Th2 cells in MPE was explored. The mechanisms of TLR2 on survival of mice bearing MPE were also investigated. MPE volume in TLR2^-/- mice was lower than that in WT mice, and the survival of TLR2^-/- mice bearing MPE was longer than that of WT mice. TLR2 deficiency increased, and TLR2 activation decreased, Th17 cells in MPE, whereas TLR2 signaling showed the contrary effects on Th2 cells. Th9 cells were increased in MPE of TLR2^-/- mice but were not influenced by TLR2 signaling. Intraperitoneal injection of anti-IL-17 monoclonal antibody (mAb), anti-IL-9 mAb, or recombinant mouse IL-4 accelerated the death of TLR2^-/- mice bearing MPE, and intraperitoneal injection anti-IL-17 mAb in TLR2^-/- mice was associated with a significantly shorter survival time than in WT mice. We have demonstrated, for the first time, that TLR2 signaling promotes the development of MPE and accelerates the death of mice bearing MPE by directly suppressing Th17 cell differentiation and directly promoting Th2 cell differentiation, and also by indirectly suppressing Th9 cell differentiation via an IL-17-dependent mechanism.

Malignant pleural effusion: from bench to bedside

Malignant pleural effusion (MPE) is a common but serious condition that is related with poor quality of life, morbidity and mortality. Its incidence and associated healthcare costs are rising and its management remains palliative, with median survival ranging from 3 to 12 months. During the last decade there has been significant progress in unravelling the pathophysiology of MPE, as well as its diagnostics, imaging, and management. Nowadays, formerly bed-ridden patients are genotyped, phenotyped, and treated on an ambulatory basis. This article attempts to provide a comprehensive overview of current advances in MPE from bench to bedside. In addition, it highlights unanswered questions in current clinical practice and suggests future directions for basic and clinical research in the field.

Th1, Th17, CXCL16 and homocysteine elevated after intracranial and cervical stent implantation

The presence of Th1 and Th17 cells has been observed as major inducers in inflammation and immune responses associated stenting. However, there is rare data on the impact of Th1, Th17, CXCL16 and homocysteine after cerebral stent implantation. Here, we performed the statistical analysis to first evaluate the variation of the Th17and Th1 cells and their related cytokines, CXCL16 and homocysteine in the peripheral blood of patients with cerebral stenting. The flow cytometry was used to detect the proportion of Th1 and Th17 cells in peripheral blood mononuclear cells (PBMCs). The enzyme-linked immunosorbent assay was used to measure the serum concentrations of IFN-γ, IL-17 and CXCL16. Plasma homocysteine was examined by immunoturbidimetry. The level of Th1, CXCL16 and homocysteine showed an increase at 3 d, followed by the continuous decrease at 7 d and 3 months. The frequency of Th17 cells increased to a peak at three days, and subsequently decreased with a higher level than baseline. Our data revealed that the variation in Th1, Th17, CXCL16 and homocysteine in peripheral blood of patients with stenting may be implicated in inflammation after intracranial and cervical stent implantation. A better understanding of these factors will provide help for further drug design and clinical therapy.

Increased soluble and membrane-bound PD-L1 contributes to immune regulation and disease progression in patients with tuberculous pleural effusion

Soluble and membrane-bound programmed death ligand-1 (sPD-L1 and mPD-L1, respectively) have been demonstrated to participate in the immune suppression of non-small cell lung cancer. However, the contribution of sPD-L1 and mPD-L1 to immune regulation and disease progression in patients with pleural effusions remains unknown. The present study evaluated the levels of sPD-L1 and membrane-bound PD-1/PD-L1 in the peripheral blood and pleural effusions of patients with tuberculous pleural effusion (TPE), malignant pleural effusion (MPE) and non-tuberculous non-malignant pleural effusion (n-TB n-M). Furthermore, selected T lymphocytes and cluster of differentiation (CD)14⁺ monocytes were co-cultured to investigate the potential effect of the PD-1/PD-L1 pathway in TPE. Levels of sPD-L1 and PD-L1 on CD14⁺ monocytes were increased in the TPE group, as compared with the MPE and n-TB n-M groups. Furthermore, sPD-L1 levels and the expression levels of PD-L1 on CD14⁺ monocytes were demonstrated to be positively correlated with interferon (IFN)-γ concentration in pleural effusions. Therefore, IFN-γ may increase the expression of PD-L1 on CD14⁺ monocytes in vitro. Cell counting kit-8 analysis demonstrated that anti-PD-L1 antibody was able to partially reverse the proliferation of T lymphocytes in the co-culture system. The results of the present study indicated that sPD-L1 or mPD-L1 are associated with the immune regulation and disease progression of TPE, and may serve as possible biomarkers of TPE. Furthermore, sPD-L1 and the PD-1/PD-L1 pathway of TPE may be associated with the Th1 immune response; therefore, an anti-PD-1/PD-L1 pathway suggests a potential immune therapy strategy for the treatment of TPE.

Interleukin-17 inhibits development of malignant pleural effusion via interleukin-9-dependent mechanism

Th17 and Th9 cells have been demonstrated to possess immune regulatory functions in malignant pleural effusion (MPE). However, whether IL-17 can affect differentiation and function of Th9 cells in MPE remains unknown. The objective of the present study was to explore the impact of IL-17 on the in vivo differentiation of Th9 cells in relation to Th2 cells in a murine model of MPE, and to explore whether IL-17 inhibits MPE formation via IL-9‒dependent mechanism. It was found that Th9 and Th2 cells were decreased in MPE from IL-17 ^-/- mice as compared with wild type mice. IL-17 deficiency inhibited Th9 and Th2 cell differentiation via suppressing transcription factors IRF4 and GATA-3, respectively. IL-17 deficiency enhanced MPE formation by promoting angiogenesis and proliferation of pleural tumors, and thus accelerated the death of mice bearing MPE. The in vivo administration of anti-IL-9 neutralizing mAb accelerated the death of WT mice; whereas administration of exogenous IL-9 improved the survival of IL-17 ^-/- mice. Our data provide the first definitive evidence that IL-17 promotes the differentiation of Th9 and Th2 cells in MPE. Our findings also demonstrate that IL-17 inhibits the formation of MPE and improves the survival of mice bearing MPE via an IL-9-dependent mechanism.

The IL-17-Th1/Th17 pathway: an attractive target for lung cancer therapy?

INTRODUCTION

There is strong pharmaceutical development of agents targeting the IL-17-TH17 pathway for the treatment of psoriasis (Ps) and psoriatic arthritis (PsA). Lung cancer accounts for 28% of all cancer-related deaths worldwide, and roughly 80% of patients with newly-diagnosed non-small cell lung cancer (NSCLC) present with metastatic disease, with a poor prognosis of around 12 months. Therefore, there is a high unmet medical need for the development of new and potent systemic treatments in this deadly disease. The emergence of immunotherapies such as anti-PD-1 or anti-PDL1 as candidate therapies in non-small cell lung cancer (NSCLC) indicates that targeting critical immuno-modulatory cytokines including those within the IL-17-Th1/Th17 axis may have proven benefit in the treatment of lung cancer. Areas covered: In this review we describe the current evidence for aberrant IL-17-Th1/Th17 settings in cancer, particularly with regard to targeting this axis in NSCLC. We further discuss the current agents under pharmaceutical development which could potentially target this axis, and discuss the current limitations and areas of concern regarding the use of these in lung cancer. Expert opinion: Current evidence suggests that moving forward agents targeting the IL-17-Th1/Th17 pathway may have novel new oncoimmunology indications in the treatment paradigm for NSCLC.

Interleukin-22 is elevated in lavage from patients with lung cancer and other pulmonary diseases

BACKGROUND

Interleukin-22 (IL-22) is involved in lung diseases such as pneumonia, asthma and lung cancer. Lavage mirrors the local environment, and may provide insights into the presence and role of IL-22 in patients.

METHODS

Bronchoscopic lavage (BL) samples (n = 195, including bronchoalveolar lavage and bronchial washings) were analysed for IL-22 using an enzyme-linked immunosorbent assay. Clinical characteristics and parameters from lavage and serum were correlated with lavage IL-22 concentrations.

RESULTS

IL-22 was higher in lavage from patients with lung disease than in controls (38.0 vs 15.3 pg/ml, p < 0.001). Patients with pneumonia and lung cancer had the highest concentrations (48.9 and 33.0 pg/ml, p = 0.009 and p < 0.001, respectively). IL-22 concentration did not correlate with systemic inflammation. IL-22 concentrations did not relate to any of the analysed cell types in BL indicating a potential mixed contribution of different cell populations to IL-22 production.

CONCLUSIONS

Lavage IL-22 concentrations are high in patients with lung cancer but do not correlate with systemic inflammation, thus suggesting that lavage IL-22 may be related to the underlying malignancy. Our results suggest that lavage may represent a distinct compartment where the role of IL-22 in thoracic malignancies can be studied.

Biological and pathological activities of interleukin-22

Interleukin (IL)-22, a member of the IL-10 family, is a cytokine secreted by several types of immune cells including IL-22(+)CD4(+) T cells (Th22) and IL-22 expressing innate leukocytes (ILC22). Recent studies have demonstrated that IL-22 is a key component in mucosal barrier defense, tissue repair, epithelial cell survival, and proliferation. Furthermore, accumulating evidence has defined both protective and pathogenic properties of IL-22 in a number of conditions including autoimmune disease, infection, and malignancy. In this review, we summarize the expression and signaling pathway and functional characteristics of the IL-22 and IL-22 receptor axis in physiological and pathological scenarios and discuss the potential to target IL-22 signaling to treat human diseases.

Quantitative and Qualitative Analysis of Tumor-Associated CD4⁺ T Cells

CD4(+) T cells comprise a significant portion of tumor-infiltrating lymphocytes. Different subsets of CD4(+) T cells exist and they exert different effector functions in tumor immunity depending on the cytokines produced going from antitumor to pro-tumor. Methods that use small aliquots of cells to identify ex vivo the frequency and functional orientation of tumor-specific CD4(+) T cells in the blood and visualization of the presence of different CD4(+) T cell subsets and their localization at the tumor site are valuable tools to determine their clinical impact in neoplastic diseases.

Interleukin-22 promotes lung cancer cell proliferation and migration via the IL-22R1/STAT3 and IL-22R1/AKT signaling pathways

Lung cancer continues to be an enormous burden on current health care systems throughout the world, with more than a million deaths every year. Previous studies have shown that interleukin-22 (IL-22) promotes survival and resistance to chemotherapy in human lung cancer cells. However, the association of IL-22 expression with recurrence of lung cancer is still unclear. In this study, we found that expression of IL-22 was upregulated in tumor tissues and serum from patients with recurrent non-small cell lung cancer (NSCLC) as compared to primary NSCLC samples. Treatment with IL-22 promoted cell proliferation and enhanced migration and invasion in A549 and H125 cell lines. Furthermore, we revealed that phosphorylation of STAT3 and AKT was highly induced by treatment with IL-22 via IL-22R1. IL-22R1 was also consistently overexpressed in recurrent NSCLC tissues. Finally, we found that siRNA-mediated depletion of IL-22R1 completely abrogated the effects of IL-22 treatment on cell proliferation and migration activity in NSCLC cell lines. Our findings indicate that IL-22 and IL-22R1 may be novel therapeutic targets for treatment of advanced NSCLC.

Intra-tumoral IFN-γ-producing Th22 cells correlate with TNM staging and the worst outcomes in pancreatic cancer

PDAC (pancreatic ductal adenocarcinoma) is the fifth leading cause of cancer-related death. The causes of this cancer remain unknown, but increasing evidence indicates a key role of the host immune response and cytokines in human carcinogenesis. Intra-tumoral IL (interleukin)-22 levels have been shown to be elevated in PDAC patients. However, little is known regarding the expression and clinical relevance of Th22 cells in human PDAC and, furthermore, which TILs (tumour-infiltrating lymphocytes) are the main producers of IL-22 is unknown. In the present study, we characterized the functional proprieties of the different subsets of IL-22-producing TILs and analysed their relationship with the TNM staging system and patient survival. We have demonstrated for the first time that, in PDAC patients, the T-cells co-producing IFN-γ (interferon γ) and exerting perforin-mediated cytotoxicity are the major intra-tumoral source of IL-22. In addition, isolated Th22 cells were able to induce apoptosis, which was antagonized by IL-22. Finally, we observed that the IL-22-producing T-cells were significantly increased in tumour tissue and that this increase was positively correlated with TNM staging of PDAC and poorer patient survival. These novel findings support the dual role of the anti-tumour immune system and that IL-22-producing cells may participate in PDAC pathogenesis. Therefore monitoring Th22 levels could be a good diagnostic parameter, and blocking IL-22 signalling may represent a viable method for anti-PDAC therapies.

Group 3 innate lymphoid cells: regulating host-commensal bacteria interactions in inflammation and cancer

A delicate balance exists between the mammalian immune system and normally beneficial commensal bacteria that colonize the gastrointestinal tract, which is necessary to maintain tissue homeostasis. Dysregulation of these interactions between the host and commensal bacteria is causally associated with chronic inflammation and the development of cancer. In contrast, recent reports have highlighted that commensal bacteria also play an essential role in promoting anti-tumor immune responses in several contexts, highlighting a paradox whereby interactions between the host and commensal bacteria can influence both pro- and anti-tumor immunity. Given the critical roles for group 3 innate lymphoid cells (ILC3s) in regulating inflammation, tissue repair and host-microbe interactions in the intestine, here we discuss new evidence that ILC3s may profoundly influence the development, progression and control of tumors. In this review, we provide an overview of recent advances in understanding the impact of commensal bacteria on tumorigenesis, discuss recent findings identifying ILC3s as critical regulators of host-microbe interactions and highlight the emerging role of this immune cell population in cancer and their potential implication as a therapeutic target.

NSFC spurs significant basic research progress of respiratory medicine in China

Over the years, research in respiratory medicine has progressed rapidly in China. This commentary narrates the role of the National Natural Science Foundation of China (NSFC) in supporting the basic research of respiratory medicine, summarizes the major progress of respiratory medicine in China, and addresses the main future research directions sponsored by the NSFC.

Interleukin (IL)-22 receptor 1 is over-expressed in primary Sjogren's syndrome and Sjögren-associated non-Hodgkin lymphomas and is regulated by IL-18

The aim of this study was to elucidate more clearly the role of interleukin (IL)-18 in modulating the IL-22 pathway in primary Sjögren's syndrome (pSS) patients and in pSS-associated lymphomas. Minor salivary glands (MSGs) from patients with pSS and non-specific chronic sialoadenitis (nSCS), parotid glands biopsies from non-Hodgkin lymphomas (NHL) developed in pSS patients, were evaluated for IL-18, IL-22, IL-22 receptor 1 (IL-22R1), IL-22 binding protein (IL-22BP) and signal transducer and activator of transcription-3 (STAT-3) expression. MSGs IL-22R1-expressing cells were characterized by confocal microscopy and flow cytometry in pSS, nSCS and healthy controls . The effect of recombinant IL-18 and IL-22 on peripheral blood mononuclear cells (PBMCs) from pSS and nSCS was studied by flow cytometry and reverse transcription-polymerase chain reaction (RT-PCR). MSGs of pSS and NHL were characterized by an imbalance between IL-22 and IL-22BP protein expression, with IL-18 and IL-22BP being expressed in a mutually exclusive manner and IL-18 and IL-22R1 being correlated directly. Aberrant expression of IL-22R1, induced by IL-18, was observed only among tissue and circulating myeloid cells of pSS patients and macrophages of NHL tissues of pSS patients, but not nSCS. IL-22R1 expression on PBMC of pSS was functional, as its stimulation with recombinant IL-22 significantly up-regulated the expression of STAT-3, IL-17 and IL-22. An IL-18-dependent aberrant expression of IL-22R1 on cells of haematopoietic origin seems to be a specific immunological signature of patients with pSS and pSS-associated lymphomas.

Toll-like receptor 4 signaling inhibits malignant pleural effusion by altering Th1/Th17 responses

Toll-like receptor 4 (TLR4) is involved in multiple malignancies; however, the role of TLR4 in the pathogenesis of malignant pleural effusion (MPE) remains unknown. The objectives of this study were to explore the impact of TLR4 signaling on the development of MPE in a murine model and to define the underline mechanisms by which TLR works. Development of MPE as well as proliferation and angiogenesis of pleural tumor were determined in TLR4(-/-) and wild type mice. Differentiation of Th1 and Th17 cells as well as their signal transductions was explored. The effects of TLR4 signaling on survival of mice bearing MPE were also investigated. Compared with wild type mice, Th1 cells were augmented, and Th17 cells were suppressed in MPE from TLR4(-/-) mice. The in vitro experiments showed that TLR4 deficiency promoted Th1 cell differentiation via enhancing STAT1 pathway and inhibited Th17 cell differentiation via suppressing STAT3 pathway. TLR4 deficiency promoted MPE formation and, thus, accelerated the death of mice bearing MPE, whereas intraperitoneal injection of anti-IFN-γ mAb or recombinant mouse IL-17 protein into TLR4(-/-) mice was associated with improved survival. Our data provides the first definitive evidence of a role for TLR4 signaling in protective immunity in the development of MPE. Our findings also demonstrate that TLR4 deficiency promotes MPE formation and accelerates mouse death by enhancing Th1 and suppressing Th17 response.

Th22 cell accumulation is associated with colorectal cancer development

AIM

To investigate the expression of Th22 cells and related cytokines in colorectal cancer (CRC) tissues, and the probably mechanism.

METHODS

CRC tumor and paratumor tissues were collected to detect the expression levels of Th22 cells and of related cytokines by immunohistochemistry, flow cytometry and real-time quantitative polymerase chain reaction (RT-qPCR). Interleukin (IL)-22 alone or with a STAT3 inhibitor was co-cultured with RKO cells in vitro to study the effects of IL-22 on colon cancer cells. IL-22 alone or with a STAT3 inhibitor was injected into a BALB/c nude mouse model with subcutaneously transplanted RKO cells to study the effects of IL-22 on colon cancer growth.

RESULTS

The percentage of Th22 cells in the CD4(+) T subset was significantly higher in tumor tissues compared with that in paratumor tissues (1.47% ± 0.083% vs 1.23% ± 0.077%, P < 0.05) as determined by flow cytometry. RT-qPCR analysis revealed that the mRNA expression levels of IL-22, aryl hydrocarbon receptor, CCL20 and CCL22 were significantly higher in tumor tissues compared with those in paratumor tissues. CCL27 mRNA also displayed a higher expression level in tumor tissues compared with that in paratumor tissues; however, these levels were not significantly different (2.58 ± 0.93 vs 2.30 ± 0.78, P > 0.05). IL-22 enhanced colon cancer cell proliferation in vitro and displayed anti-apoptotic effects; these effects were blocked by adding a STAT3 inhibitor. IL-22 promoted tumor growth in BALB/c nude mice; however, this effect was reversed by adding a STAT3 inhibitor.

CONCLUSION

Th22 cells that accumulate in CRC may be associated with the chemotactic effect of the tumor microenvironment. IL-22 is associated with CRC development, most likely via STAT3 activation.

IL22/IL-22R pathway induces cell survival in human glioblastoma cells

Interleukin-22 (IL-22) is a member of the IL-10 cytokine family that binds to a heterodimeric receptor consisting of IL-22 receptor 1 (IL-22R1) and IL-10R2. IL-22R expression was initially characterized on epithelial cells, and plays an essential role in a number of inflammatory diseases. Recently, a functional receptor was detected on cancer cells such as hepatocarcinoma and lung carcinoma, but its presence was not reported in glioblastoma (GBM). Two GBM cell lines and 10 primary cell lines established from patients undergoing surgery for malignant GBM were used to investigate the expression of IL-22 and IL-22R by using quantitative RT-PCR, western blotting and confocal microscopy studies. The role of IL-22 in proliferation and survival of GBM cell lines was investigated in vitro by BrdU and ELISA cell death assays. We report herein that the two subunits of the IL-22R complex are expressed on human GBM cells. Their activation, depending on exogenous IL-22, induced antiapoptotic effect and cell proliferation. IL-22 treatment of GBM cells resulted in increased levels of phosphorylated Akt, STAT3 signaling protein and its downstream antiapoptotic protein Bcl-xL and decreased level of phosphorylated ERK1/2. In addition, IL-22R subunits were expressed in all the 10 tested primary cell lines established from GBM tumors. Our results showed that IL-22R is expressed on GBM established and primary cell lines. Depending on STAT3, ERK1/2 and PI3K/Akt pathways, IL-22 induced GBM cell survival. These data are consistent with a potential role of IL-22R in tumorigenesis of GBM. Since endogenous IL-22 was not detected in all studied GBM cells, we hypothesize that IL-22R could be activated by immune microenvironmental IL-22 producing cells.

Th22 cells increase in poor prognosis multiple myeloma and promote tumor cell growth and survival

There is increased production of plasmacytoid dendritic cells (pDCs) in the bone marrow (BM) of multiple myeloma (MM) patients and these favor Th22 cell differentiation. Here, we found that the frequency of interleukin (IL)-22⁺IL-17^-IL-13⁺ T cells is significantly increased in peripheral blood (PB) and BM of stage III and relapsed/refractory MM patients compared with healthy donors and patients with asymptomatic or stage I/II disease. Th22 cells cloned from the BM of MM patients were CCR6⁺CXCR4⁺CCR4⁺CCR10^- and produced IL-22 and IL-13 but not IL-17. Furthermore, polyfunctional Th22-Th2 and Th22-Th1 clones were identified based on the co-expression of additional chemokine receptors and cytokines (CRTh2 or CXCR3 and IL-5 or interferon gamma [IFNγ], respectively). A fraction of MM cell lines and primary tumors aberrantly expressed the IL-22RA1 and IL-22 induced STAT-3 phosphorylation, cell growth, and resistance to drug-induced cell death in MM cells. IL-13 treatment of normal BM mesenchymal stromal cells (MSCs) induced STAT-6 phosphorylation, adhesion molecule upregulation, and increased IL-6 production and significantly favored MM cell growth compared with untreated BM MSCs. Collectively, our data show that increased frequency of IL-22⁺IL-17^-IL-13⁺ T cells correlates with poor prognosis in MM through IL-22 and IL-13 protumor activity and suggest that interference with IL-22 and IL-13 signaling pathways could be exploited for therapeutic intervention.

Role of Th22 cells in pathogenesis of malignant ascites in patients with hepatic carcinoma

AIM: To examine the frequency of Th22 cells in malignant ascites (MA) from patients with hepatic carcinoma and elucidate the effects of chemokine-chemokine receptor interactions on recruitment of Th22 cells into MA.

METHODS: Twenty-six hepatic carcinoma patients with MA and 15 healthy controls were included. The expression of interleukin-22 (IL-22), chemokine receptor (CCR) 4, CCR6 and CCR10 were examined in patients with MA and healthy controls by flow cytometry. The levels of IL-22, as well as chemokines CCL20, CCL22 and CCL27 in MA and sera were examined by enzyme-linked immunosorbent assay.

RESULTS: The proportions of Th22 cells and IL-22 positive cells were significantly elevated in MA patients compared with those in peripheral blood from both patients with MA and healthy controls. The levels of chemokines CCL20, CCL22 and CCL27 were significantly higher in MA than in serum. Th22 cells expressed high levels of CCR6, CCR4 and CCR10, which are ligands for CCL20, CCL22 and CCL27, respectively. The proportion of Th22 cells had a positive correlation with the proportion of Th17 cells as well as IL-22 level in MA patients.

CONCLUSION: The recruitment of Th22 cells into MA might be induced via a chemokine-dependent mechanism. The overrepresentation of Th22 cells into MA could be induced by CCL20-CCR6, CCL22-CCR4 and/or CCL27-CCR10 axes. These findings suggest that Th22 cells may be implicated in the pathogenesis of MA, and Th22 cells may be a reasonable cellular target for therapeutic intervention.

Tumor antigen-specific CD4+ T cells in cancer immunity: from antigen identification to tumor prognosis and development of therapeutic strategies

CD4(+) T cells comprise a large fraction of tumor infiltrating lymphocytes and it is now established that they may exert an important role in tumor immune-surveillance. Several CD4(+) T cell subsets [i.e. T helper (Th)1, Th2, T regulatory (Treg), Th17, Th22 and follicular T helper (Tfh)] have been described and differentiation of each subset depends on both the antigen presenting cells responsible for its activation and the cytokine environment present at the site of priming. Tumor antigen-specific CD4(+) T cells with different functional activity have been found in the blood of cancer patients and different CD4(+) T cell subsets have been identified at the tumor site by the expression of specific transcription factors and the profile of secreted cytokines. Importantly, depending on the subset, CD4(+) T cells may exert antitumor versus pro-tumor functions. Here we review the studies that first identified the presence of tumor-specific CD4(+) T cells in cancer patients, the techniques used to identify the tumor antigens recognized, the role of the different CD4(+) T cell subsets in tumor immunity and in cancer prognosis and the development of therapeutic strategies aimed at activating efficient antitumor CD4(+) T cell effectors.

The role of the IL-22/IL-22R1 axis in cancer

Interleukin-22 (IL-22) is an IL-10 family cytokine produced by T cells and innate lymphoid cells. The IL-22 signaling pathway orchestrates mucosal immune defense and tissue regeneration through pleiotropic effects including pro-survival signaling, cell migration, dysplasia and angiogenesis. While these functions can prevent initial establishment of tumors, they can also be hijacked by aggressive cancers to enhance tumor growth and metastasis. Thus, the role of the IL-22/IL-22R1 axis in cancer is complex and context-specific. Evidence of IL-22 involvement manifests as dysregulation of IL-22 expression and signaling in patients with many common cancers including those of the gut, skin, lung and liver. Unlike other cancer-associated cytokines, IL-22 has restricted tissue specificity as its unique receptor IL-22R1 is exclusively expressed on epithelial and tissue cells, but not immune cells. This makes it an attractive target for therapy as there is potential achieve anti-tumor immunity with fewer side effects. This review summarizes current findings on functions of IL-22 in association with general mechanisms for tumorigenesis as well as specific contributions to particular cancers, and ponders how best to approach further research in the field.

Th22 cells are associated with hepatocellular carcinoma development and progression

OBJECTIVE

IL-22-producing CD4(+) T helper cells (Th22 cells) have been identified as major inducers of tissue inflammation and immune responses. Currently, no previous study explored the role of Th22 cells in the pathogenesis of hepatocellular carcinoma (HCC). The study aimed to determine the biological function of Th22 cells and its effector IL-22 in HCC patients.

METHODS

Forty-five HCC patients and 19 healthy controls were recruited and their peripheral blood was collected. The fresh HCC tissues, adjacent HCC tissues and ten normal liver tissues were also collected. Flow cytometry analysis was used to determine the frequencies of circulating Th22 cells and Th17 cells. Serum IL-22 levels were tested by enzyme-linked immunosorbent assay (ELISA). Immunohistochemical staining and real-time polymerase chain reaction (PCR) were used to detect IL-22 protein and mRNA in tissues specimens, respectively.

RESULTS

Circulating Th22 cells, Th17 cells and serum IL-22 levels were significantly elevated in HCC patients compared with those of healthy controls (P<0.001). Th22 cells were showed to be positively correlated with IL-22 in HCC patients (P<0.05), but not in healthy controls. No significant differences were found in HCC patients with HBeAg positivity or negativity in term of Th22 cells and serum IL-22 levels. The expression of IL-22 protein and mRNA was highest in HCC tissues, followed by adjacent HCC tissues and normal liver tissues. Furthermore, Th22 cells, serum IL-22 levels and IL-22 mRNA were elevated at stage III-IV compared with stage I-II of HCC (P<0.05).

CONCLUSIONS

Elevation of circulating Th22 cells and IL-22 may be implicated in the pathogenesis of HCC, and potentially be cellular targets for therapeutic intervention.