The IL-18 antagonist IL-18-binding protein is produced in the human ovarian cancer microenvironment

GD2 Target Antigen and CAR T Cells: Does It Take More Than Two to Tango?

Over the past decade, chimeric antigen receptor T cells have emerged as a breakthrough cancer therapy in selected hematologic malignancies. Translating the success of this therapy to solid tumors is challenging. In this issue, we discuss strategies potentially useful to increase the chimeric antigen receptor T-cell efficacy in this clinical indication. See related article by Fischer-Riepe et al., p. 3564.

The potential role of interleukins and interferons in ovarian cancer

Ovarian cancer poses significant challenges and remains a highly lethal disease with limited treatment options. In the context of ovarian cancer, interleukins (ILs) and interferons (IFNs), important cytokines that play crucial roles in regulating the immune system, have emerged as significant factors influencing its development. This article provides a comprehensive review of the involvement of various ILs, including those from the IL-1 family, IL-2 family, IL-6 family, IL-8 family, IL-10 family, and IL-17 family, in ovarian cancer. The focus is on their impact on tumor growth, metastasis, and their role in evading immune responses within the tumor microenvironment. Additionally, the article conducts an in-depth examination of the oncogenic or antitumor roles of each IL in the context of ovarian cancer pathogenesis and progression. Besides, we elucidated the enhancements in the treatment of ovarian cancer through the utilization of type-I IFN and type-II IFN. Recent research has shed light on the intricate mechanisms through which specific ILs and IFNs contribute to the advancement of the disease. By incorporating recent findings, this review also seeks to inspire further investigations into unexplored mechanisms, fostering ongoing research to develop more effective therapeutic strategies for ovarian cancer. Moreover, through an in-depth analysis of IL- and IFN-associated clinical trials, we have highlighted their promising potential of in the treatment of ovarian cancer. These clinical trials serve to reinforce the significant outlook for utilizing ILs and IFNs as therapeutic agents in combating this disease.

Interleukin-18 in cancer immunology and immunotherapy

INTRODUCTION

Interleukin-18 (IL-18) is a myeloid leukocyte inflammatory mediator whose main known function is to elicit IFNγ secretion from T and NK cells.

AREAS COVERED

This function offers potential in cancer immunotherapy but as a single treatment, preclinical and clinical antitumor activities are modest. IL-18 bioactivity is chiefly downregulated by a decoy soluble receptor named IL18-binding protein (IL-18BP) that is induced by IFNγ as a negative feedback mechanism. Recent advances indicate promising efficacy of IL-18 at armoring CAR-T cells for the treatment of hematological malignancies. Preclinical research has also yielded IL-18 constructs that do not bind IL-18BP but have preserved activity on the receptor and exert markedly increased antitumor effects. Indeed, agents of this kind are undergoing clinical trials. The synergistic effects of IL-18 and IL-12 in combination to induce IFNγ are extremely potent but are toxic if systemically delivered. In mouse models, IL-12 and decoy-resistant variants of IL-18 can be efficaciously used as local treatments for tumors by exploiting mRNA intratumoral co-delivery. Moreover, antitumor T cells can be transiently engineered with mRNAs encoding this combination of cytokines to attain efficacious synergistic effects also upon intratumoral delivery.

EXPERT OPINION

IL-18 certainly holds promise for immunotherapy in combination with other agents and for local approaches.

The Role of IL-18 in P2RX7-Mediated Antitumor Immunity

Cancer is the leading cause of death worldwide despite the variety of treatments that are currently used. This is due to an innate or acquired resistance to therapy that encourages the discovery of novel therapeutic strategies to overcome the resistance. This review will focus on the role of the purinergic receptor P2RX7 in the control of tumor growth, through its ability to modulate antitumor immunity by releasing IL-18. In particular, we describe how the ATP-induced receptor activities (cationic exchange, large pore opening and NLRP3 inflammasome activation) modulate immune cell functions. Furthermore, we recapitulate our current knowledge of the production of IL-18 downstream of P2RX7 activation and how IL-18 controls the fate of tumor growth. Finally, the potential of targeting the P2RX7/IL-18 pathway in combination with classical immunotherapies to fight cancer is discussed.

mRNAs encoding IL-12 and a decoy-resistant variant of IL-18 synergize to engineer T cells for efficacious intratumoral adoptive immunotherapy

Interleukin-12 (IL-12) gene transfer enhances the therapeutic potency of adoptive T cell therapies. We previously reported that transient engineering of tumor-specific CD8 T cells with IL-12 mRNA enhanced their systemic therapeutic efficacy when delivered intratumorally. Here, we mix T cells engineered with mRNAs to express either single-chain IL-12 (scIL-12) or an IL-18 decoy-resistant variant (DRIL18) that is not functionally hampered by IL-18 binding protein (IL-18BP). These mRNA-engineered T cell mixtures are repeatedly injected into mouse tumors. Pmel-1 T cell receptor (TCR)-transgenic T cells electroporated with scIL-12 or DRIL18 mRNAs exert powerful therapeutic effects in local and distant melanoma lesions. These effects are associated with T cell metabolic fitness, enhanced miR-155 control on immunosuppressive target genes, enhanced expression of various cytokines, and changes in the glycosylation profile of surface proteins, enabling adhesiveness to E-selectin. Efficacy of this intratumoral immunotherapeutic strategy is recapitulated in cultures of tumor-infiltrating lymphocytes (TILs) and chimeric antigen receptor (CAR) T cells on IL-12 and DRIL18 mRNA electroporation.

An emerging role of inflammasomes in spinal cord injury and spinal cord tumor

Spinal cord injury (SCI) and spinal cord tumor are devastating events causing structural and functional impairment of the spinal cord and resulting in high morbidity and mortality; these lead to a psychological burden and financial pressure on the patient. These spinal cord damages likely disrupt sensory, motor, and autonomic functions. Unfortunately, the optimal treatment of and spinal cord tumors is limited, and the molecular mechanisms underlying these disorders are unclear. The role of the inflammasome in neuroinflammation in diverse diseases is becoming increasingly important. The inflammasome is an intracellular multiprotein complex and participates in the activation of caspase-1 and the secretion of pro-inflammatory cytokines such as interleukin (IL)-1β and IL-18. The inflammasome in the spinal cord is involved in the stimulation of immune-inflammatory responses through the release of pro-inflammatory cytokines, thereby mediating further spinal cord damage. In this review, we highlight the role of inflammasomes in SCI and spinal cord tumors. Targeting inflammasomes is a promising therapeutic strategy for the treatment of SCI and spinal cord tumors.

Small secretory proteins of immune cells can modulate gynecological cancers

Small secretory proteins of immune cells are mostly Cytokines, which include chemokines, interleukins, interferons, lymphokines and tumor necrosis factors but not hormones or growth factors. These secretory proteins are the molecular messengers and primarily involved in autocrine, paracrine and endocrine signaling as immunomodulating agents. Hence, these proteins actually regulate the cells of immune system to communicate with one another to produce a synchronized, robust, still self-regulated response to a specific antigen. Chemokines are smaller secreted proteins that control overall immune cell movement and location; these chemokines are divided into 4 subgroups, namely, CXC, CC, CX3C and C according to the position of 4 conserved cysteine residues. Complete characterization of cytokines and chemokines can exploit their vast signaling networks to develop cancer treatments. These secretory proteins like IL-6, IL-10, IL-12, TNFα, CCL2, CXCL4 & CXCL8 are predominantly expressed in most of the gynecological cancers, which directly stimulate immune effector cells and stromal cells at the tumor site and augment tumor cell recognition by cytotoxic T-cells. Hence; these secretory proteins are the major regulators, which can actually modulate all kinds of gynecological cancers. Furthermore, advancements in adoptive T-cell treatment have relied on the use of multiple cytokines/chemokines to establish a highly regulated environment for anti-tumor T cell growth. A number of in vitro studies as well as animal models and clinical subjects have also shown that cytokines/chemokines have broad antitumor activity, which has been translated into a number of cancer therapy approaches. This review will focus on the foremost cytokines & chemokines involved in the majority of the gynecological malignancies and discuss their basic biology as well as clinical applications.

Interleukin-18 Binding Protein in Immune Regulation and Autoimmune Diseases

Natural soluble antagonist and decoy receptor on the surface of the cell membrane are evolving as crucial immune system regulators as these molecules are capable of recognizing, binding, and neutralizing (so-called inhibitors) their targeted ligands. Eventually, these soluble antagonists and decoy receptors terminate signaling by prohibiting ligands from connecting to their receptors on the surface of cell membrane. Interleukin-18 binding protein (IL-18BP) participates in regulating both Th1 and Th2 cytokines. IL-18BP is a soluble neutralizing protein belonging to the immunoglobulin (Ig) superfamily as it harbors a single Ig domain. The Ig domain is essential for its binding to the IL-18 ligand and holds partial homology to the IL-1 receptor 2 (IL-1R2) known as a decoy receptor of IL-1α and IL-1β. IL-18BP was defined as a unique soluble IL-18BP that is distinct from IL-18Rα and IL-18Rβ chain. IL-18BP is encoded by a separated gene, contains 8 exons, and is located at chr.11 q13.4 within the human genome. In this review, we address the difference in the biological activity of IL-18BP isoforms, in the immunity balancing Th1 and Th2 immune response, its critical role in autoimmune diseases, as well as current clinical trials of recombinant IL-18BP (rIL-18BP) or equivalent.

A methylation-driven genes prognostic signature and the immune microenvironment in epithelial ovarian cancer

Aberrant gene methylation has been implicated in the development and progression of tumors. In this study, we aimed to identity methylation driven genes involved in epithelial ovarian cancer (EOC) to establish a prognostic signature for patients with EOC. We identified and verified 6 MDGs that are closely related to the prognosis of ovarian cancer. A prognostic risk score model and nomogram for predicting the prognosis of ovarian cancer were constructed based on the six MDGs. It can also effectively reflect the immune environment and immunotherapy response of ovarian cancer. These MDGs have great significance to the implementation of individualized treatment and disease monitoring of ovarian cancer patients.

Single-Molecule RNA Sequencing Reveals IFNγ-Induced Differential Expression of Immune Escape Genes in Merkel Cell Polyomavirus-Positive MCC Cell Lines

Merkel cell carcinoma (MCC) is a rare and highly aggressive cancer, which is mainly caused by genomic integration of the Merkel cell polyomavirus and subsequent expression of a truncated form of its large T antigen. The resulting primary tumor is known to be immunogenic and under constant pressure to escape immune surveillance. Because interferon gamma (IFNγ), a key player of immune response, is secreted by many immune effector cells and has been shown to exert both anti-tumoral and pro-tumoral effects, we studied the transcriptomic response of MCC cells to IFNγ. In particular, immune modulatory effects that may help the tumor evade immune surveillance were of high interest to our investigation. The effect of IFNγ treatment on the transcriptomic program of three MCC cell lines (WaGa, MKL-1, and MKL-2) was analyzed using single-molecule sequencing via the Oxford Nanopore platform. A significant differential expression of several genes was detected across all three cell lines. Subsequent pathway analysis and manual annotation showed a clear upregulation of genes involved in the immune escape of tumor due to IFNγ treatment. The analysis of selected genes on protein level underlined our sequencing results. These findings contribute to a better understanding of immune escape of MCC and may help in clinical treatment of MCC patients. Furthermore, we demonstrate that single-molecule sequencing can be used to assess characteristics of large eukaryotic transcriptomes and thus contribute to a broader access to sequencing data in the community due to its low cost of entry.

IL-18 and IL-18 binding protein are related to disease severity and parasitemia during falciparum malaria

BACKGROUND

Several inflammatory molecules participate in the immune response to malaria. Interleukin (IL)-18 is an inflammatory cytokine activated by NLRP3 inflammasomes. In clinical falciparum malaria, with and without HIV co-infection, data on IL-18 and in particular on its binding protein, IL-18bp, is scarce.

METHODS

Clinical data and blood samples were collected from adults in Mozambique with P. falciparum infection, with (n = 70) and without (n = 61) HIV co-infection, from HIV-infected patients with similar symptoms without malaria (n = 58) and from healthy controls (n = 52). In vitro studies were performed in endothelial cells using hemozoin crystals.

RESULTS

(i) IL-18 and IL-18bp were markedly up-regulated during falciparum malaria with particular high levels in malaria patients co-infected with HIV and severe malaria disease. (ii) In the malaria group as a whole, both IL-18 and IL-18bp were positively correlated with disease severity, parasitemia, and endothelial cell activation as assessed by vWF in plasma. (iii) Whereas there was no change in IL-18 levels in malaria patients co-infected with HIV during follow-up, the patients with malaria only had slightly increased IL-18 levels. Further, the IL-18pb levels declined and thereby contributed to an increase in IL-18/IL-18bp ratio in all subgroups of malaria patients. (iv) IL-27, previously shown to be up-regulated in this malaria cohort, markedly induced a release of IL-18bp from endothelial cells in vitro, and notably, this presumably anti-inflammatory effect was counteracted by hemozoin.

CONCLUSIONS

Our findings suggest that the IL-18 system could be an important mediator in the immune pathogenesis during falciparum malaria, potentially also representing a target for therapy.

Stem-like tumor cells and proinflammatory cytokines in the ascitic fluid of ovarian cancer patients

Ovarian cancer (OC) is able to develop implantation metastases in the abdominal cavity. Ascites is potentially useful for evaluating cancer features. The aim of the study was to assess the content of stem-like tumor cells and inflammatory mediators in ascites of OC. The prospective study included 11 patients with primary OC having ascites, 8 patients with benign ovarian tumors having ascites and 22 healthy women. In ascitic fluid obtained by laparocentesis, the populations of tumor stem-like cells were determined on a Cytoflex S` flow cytometer (Beckman Coulter, USA) and CytExpert Software using monoclonal antibodies to CD45, CD44 and CD133. The cytokine profiles of ascitic fluid and blood serum (IL-1β, IL-18, IL-4, IL-10 and VEGF) were assessed by ELISA. Stem-like cells were found in all samples. 5 cell populations were evaluated. The number of cells expressing both markers: CD44 + and CD133+, was the lowest. The highest, about 32%, was the number of CD44+ cells. The number of cells CD45-CD44+CD133- in ascites strongly positively correlated with the content of IL-10 in ascites, and the numbers of CD45-CD133+ and CD45-CD44-CD133+ - with the level of VEGF in blood serum. No correlations were found between the numbers of stem-like cells and the disease stage or the level of CA125 in blood. The combination of IL-4 and IL-10 in ascites had the greatest significance in predicting the disease stage. These results suggest a relationship between the levels of VEGF, IL-10, and cancer stem cells in the OC ascites. Stem-like cells in OC ascites are heterogeneous and are present even at an early stage of the disease. It seems promising to study cell populations and cytokine profile of ascites together, to assess the biomarker potential of their combination.

IL-30† (IL-27A): a familiar stranger in immunity, inflammation, and cancer

Over the years, interleukin (IL)-27 has received much attention because of its highly divergent, sometimes even opposing, functions in immunity. IL-30, the p28 subunit that forms IL-27 together with Ebi3 and is also known as IL-27p28 or IL-27A, has been considered a surrogate to represent IL-27. However, it was later discovered that IL-30 can form complexes with other protein subunits, potentially leading to overlapping or discrete functions. Furthermore, there is emerging evidence that IL-30 itself may perform immunomodulatory functions independent of Ebi3 or other binding partners and that IL-30 production is strongly associated with certain cancers in humans. In this review, we will discuss the biology of IL-30 and other IL-30-associated cytokines and their functions in inflammation and cancer.

Studying the ways that interleukin IL-30 regulates immune responses may provide novel insights into tumor development and inflammatory conditions. Interleukins are a diverse family of proteins involved in intercellular communications and immunity, where they can exert divergent and even opposing functions. Booki Min at Northwestern University in Chicago, USA, and co-workers reviewed the current understanding of IL-30 and its links to inflammation and cancer. IL-30 forms the IL-27 complex with the Ebi3 protein and was thought to be a surrogate for IL-27 in terms of activity. However, recent insights suggest that IL-30 may perform discrete immune modulation functions. Elevated IL-30 secretion is linked to prostate and breast cancer development. Extensive research is needed into the formation of IL-30, its associated protein interactions, and the development of a suitable animal model.

The Dual Role of STAT1 in Ovarian Cancer: Insight Into Molecular Mechanisms and Application Potentials

The signal transducer and activator of transcription 1 (STAT1) is a transducer protein and acts as a transcription factor but its role in ovarian cancer (OC) is not completely understood. Practically, there are two-faced effects of STAT1 on tumorigenesis in different kinds of cancers. Existing evidence reveals that STAT1 has both tumor-suppressing and tumor-promoting functions involved in angiogenesis, cell proliferation, migration, invasion, apoptosis, drug resistance, stemness, and immune responses mainly through interacting and regulating target genes at multiple levels. The canonical STAT1 signaling pathway shows that STAT1 is phosphorylated and activated by the receptor-activated kinases such as Janus kinase in response to interferon stimulation. The STAT1 signaling can also be crosstalk with other signaling such as transforming growth factor-β signaling involved in cancer cell behavior. OC is often diagnosed at an advanced stage due to symptomless or atypical symptoms and the lack of effective detection at an early stage. Furthermore, patients with OC often develop chemoresistance and recurrence. This review focuses on the multi-faced role of STAT1 and highlights the molecular mechanisms and biological functions of STAT1 in OC.

Cytokines Orchestrating the Natural Killer-Myeloid Cell Crosstalk in the Tumor Microenvironment: Implications for Natural Killer Cell-Based Cancer Immunotherapy

Natural killer (NK) cells are endowed with germline-encoded receptors that enable them to detect and kill malignant cells without prior priming. Over the years, overwhelming evidence has identified an essential role for NK cells in tumor immune surveillance. More recently, clinical trials have also highlighted their potential in therapeutic settings. Yet, data show that NK cells can be dysregulated within the tumor microenvironment (TME), rendering them ineffective in eradicating the cancer cells. This has been attributed to immune suppressive factors, including the tumor cells per se, stromal cells, regulatory T cells, and soluble factors such as reactive oxygen species and cytokines. However, the TME also hosts myeloid cells such as dendritic cells, macrophages, neutrophils, and myeloid-derived suppressor cells that influence NK cell function. Although the NK-myeloid cell crosstalk can promote anti-tumor responses, myeloid cells in the TME often dysregulate NK cells via direct cell-to-cell interactions down-regulating key NK cell receptors, depletion of nutrients and growth factors required for NK cell growth, and secretion of metabolites, chemokines and cytokines that ultimately alter NK cell trafficking, survival, and cytotoxicity. Here, we review the complex functions of myeloid-derived cytokines in both supporting and suppressing NK cells in the TME and how NK cell-derived cytokines can influence myeloid subsets. We discuss challenges related to these interactions in unleashing the full potential of endogenous and adoptively infused NK cells. Finally, we present strategies aiming at improving NK cell-based cancer immunotherapies via pathways that are involved in the NK-myeloid cell crosstalk in the TME.

Integrated multi-omics analysis of genomics, epigenomics, and transcriptomics in ovarian carcinoma

In this study, we identified prognostic biomarkers in ovarian carcinoma by integrating multi-omics DNA copy number variation (CNV) and methylation variation (MET) data. CNV, MET, and messenger RNA (mRNA) expression were examined in 351 ovarian carcinoma patients. Genes for which expression was correlated with DNA copy-number or DNA methylation were identified; three ovarian carcinoma gene subtypes were defined based on these correlations. Overall survival and B cell scores were lower, while the macrophage cell score was higher, in the DNA imprinting centre 1 (iC1) subtype than in the iC2 and iC3 subtypes. Comparison of CNV, MET, and mRNA expression among the subtypes identified two genes, ubiquitin B (UBB) and interleukin 18 binding protein (IL18BP), that were associated with prognosis. Mutation spectrum results based on subtype indicated that UBB and IL18BP expression may be influenced by mutation loci. Mutation levels were higher in iC1 samples than in iC2 or iC3 samples, indicating that the iC1 subtype is associated with disease progression. This integrated multi-omics analysis of genomics, epigenomics, and transcriptomics provides new insight into the molecular mechanisms of ovarian carcinoma and may help identify biomolecular markers for early disease diagnosis.

IL-18BP is a secreted immune checkpoint and barrier to IL-18 immunotherapy

Cytokines were the first modern immunotherapies to produce durable responses in advanced cancer, but their application has been hampered by modest efficacy and limited tolerability^1,2. In an effort to identify alternative cytokine pathways for immunotherapy, we found that components of the Interleukin-18 (IL-18) pathway are upregulated on tumor infiltrating lymphocytes (TIL), suggesting that IL-18 therapy could enhance anti-tumor immunity. However, recombinant IL-18 previously failed to demonstrate efficacy in clinical trials³. Here we show that IL-18BP, a high-affinity IL-18 decoy receptor, is frequently upregulated in diverse human and murine tumors and limits the anti-tumor activity of IL-18 in mice. Using directed evolution, we engineered a ‘decoy-resistant’ IL-18 (DR-18), which maintains signaling potential, but is impervious to inhibition by IL-18BP. In contrast to wild-type IL-18, DR-18 exhibits potent anti-tumor efficacy in mouse tumor models by promoting the development of poly-functional effector CD8⁺ T cells, decreasing the prevalence of exhausted CD8⁺ T cells expressing TOX, and expanding the pool of stem-like TCF1⁺ precursor CD8⁺ T cells. DR-18 also enhances NK cell activity and maturation to effectively treat anti-PD-1 resistant tumors that have lost MHC class I surface expression. These results highlight the potential of the IL-18 pathway for immunotherapeutic intervention and implicate IL-18BP as a major therapeutic barrier.

Cytokine-Induced Guanylate Binding Protein 1 (GBP1) Release from Human Ovarian Cancer Cells

We showed that IL-27 shares several effects with IFN-γ in human cancer cells. To identify novel extracellular mediators, potentially involved in epithelial ovarian cancer (EOC) biology, we analyzed the effect of IL-27 or IFN-γ on the secretome of cultured EOC cells by mass-spectrometry (nano-UHPLC-MS/MS). IL-27 and IFN-γ modulate the release of a limited fraction of proteins among those induced in the whole cell. We focused our attention on GBP1, a guanylate-binding protein and GTPase, which mediates several biological activities of IFNs. Cytokine treatment induced GBP1, 2, and 5 expressions in EOC cells, but only GBP1 was secreted. ELISA and immunoblotting showed that cytokine-stimulated EOC cells release full-length GBP1 in vitro, through non-classical pathways, not involving microvesicles. Importantly, full-length GBP1 accumulates in the ascites of most EOC patients and ex-vivo EOC cells show constitutive tyrosine-phosphorylated STAT1/3 proteins and GBP1 expression, supporting a role for Signal Transducer And Activator Of Transcription (STAT)-activating cytokines in vivo. High GBP1 gene expression correlates with better overall survival in the TCGA (The Cancer Genome Atlas) dataset of EOC. In addition, GBP1 transfection partially reduced EOC cell viability in an MTT assay. Our data show for the first time that cytokine-stimulated tumor cells release soluble GBP1 in vitro and in vivo and suggest that GBP1 may have anti-tumor effects in EOC.

IL-18/IL-18BP and IL-22/IL-22BP: Two interrelated couples with therapeutic potential

Interleukin (IL)-18 and IL-22 are key components of cytokine networks that play a decisive role in (pathological) inflammation, host defense, and tissue regeneration. Tight regulation of cytokine-driven signaling, inflammation, and immunoactivation is supposed to enable nullification of a given deleterious trigger without mediating overwhelming collateral tissue damage or even activating a cancerous face of regeneration. In fact, feedback regulation by specific cytokine opponents is regarded as a major means by which the immune system is kept in balance. Herein, we shine a light on the interplay between IL-18 and IL-22 and their opponents IL-18 binding protein (IL-18BP) and IL-22BP in order to provide integrated information on their biology, pathophysiological significance, and prospect as targets and/or instruments of therapeutic intervention.

IL-18 and IL-1β Gene Polymorphisms: The Plausible Risk Factors for Chronic Hepatitis B

Chronic inflammation is the main risk factor for induction of liver cirrhosis and also hepatocellular carcinoma in chronic hepatitis B (CHB) patients. Although our knowledge is growing regarding molecular mechanisms of immune responses against viruses, the main mechanisms that lead to the progression of chronic inflammation and then CHB are yet to be clarified. IL-18 and IL-1β are the members of the IL-1 family and produced in the cytoplasm of a wide range of immune and nonimmune cells and activated by inflammasome pathways. The cytokines play key roles in the pathologies of CHB. IL-18 and IL-1β productions are altered in CHB patients. It has been hypothesized that the polymorphisms within IL-18 and IL-1β genes may be the main reasons for the induction of chronic inflammation in CHB patients. This review article discusses the related investigations regarding the main correlation between the polymorphisms within IL-18 and IL-1β genes and CHB pathogenesis.

Interleukin-18 in Health and Disease

Interleukin (IL)-18 was originally discovered as a factor that enhanced IFN-γ production from anti-CD3-stimulated Th1 cells, especially in the presence of IL-12. Upon stimulation with Ag plus IL-12, naïve T cells develop into IL-18 receptor (IL-18R) expressing Th1 cells, which increase IFN-γ production in response to IL-18 stimulation. Therefore, IL-12 is a commitment factor that induces the development of Th1 cells. In contrast, IL-18 is a proinflammatory cytokine that facilitates type 1 responses. However, IL-18 without IL-12 but with IL-2, stimulates NK cells, CD4⁺ NKT cells, and established Th1 cells, to produce IL-3, IL-9, and IL-13. Furthermore, together with IL-3, IL-18 stimulates mast cells and basophils to produce IL-4, IL-13, and chemical mediators such as histamine. Therefore, IL-18 is a cytokine that stimulates various cell types and has pleiotropic functions. IL-18 is a member of the IL-1 family of cytokines. IL-18 demonstrates a unique function by binding to a specific receptor expressed on various types of cells. In this review article, we will focus on the unique features of IL-18 in health and disease in experimental animals and humans.

Activated Eosinophils Exert Antitumorigenic Activities in Colorectal Cancer

Immunotherapies targeting T lymphocytes are revolutionizing cancer therapy but only benefit a subset of patients, especially in colorectal cancer. Thus, additional insight into the tumor microenvironment (TME) is required. Eosinophils are bone marrow-derived cells that have been largely studied in the context of allergic diseases and parasite infections. Although tumor-associated eosinophilia has been described in various solid tumors including colorectal cancer, knowledge is still missing regarding eosinophil activities and even the basic question of whether the TME promotes eosinophil recruitment without additional manipulation (e.g., immunotherapy) is unclear. Herein, we report that eosinophils are recruited into developing tumors during induction of inflammation-induced colorectal cancer and in mice with the Apc^{min /+} genotype, which develop spontaneous intestinal adenomas. Using adoptive transfer and cytokine neutralization experiments, we demonstrate that the TME supported prolonged eosinophil survival independent of IL5, an eosinophil survival cytokine. Tumor-infiltrating eosinophils consisted of degranulating eosinophils and were essential for tumor rejection independently of CD8⁺ T cells. Transcriptome and proteomic analysis revealed an IFNγ-linked signature for intratumoral eosinophils that was different from that of macrophages. Our data establish antitumorigenic roles for eosinophils in colorectal cancer. These findings may facilitate the development of pharmacologic treatments that could unleash antitumor responses by eosinophils, especially in colorectal cancer patients displaying eosinophilia.

Investigation of Interleukin-27 in the Sera of Nonmelanoma Skin Cancer Patients

IL-27 has been shown to have both tumor promoting and suppressing functions. IL-27, with its diverse influences on immune responses, has not been studied extensively in nonmelanoma skin cancers (NMSC), including Squamous and Basal Cell Carcinomas (SCC and BCC), and its roles in tumor initiation, progression, and its probable use in NMSC treatment have yet to be unveiled. A cross-sectional analytical study was designed to investigate the serum levels of IL-27 in NMSC patients in comparison to normal individuals. Levels of IL-27 in the sera of 60 NMSC patients along with 28 healthy controls were measured by means of quantitative enzyme-linked immunosorbent assay (ELISA). In this study we observed that IL-27 serum levels were significantly higher in NMSC patients in comparison to healthy individuals (0.0134 versus 0.0008 ng/ml; P<0.001). Furthermore, when subcategorized based on pathological diagnosis, both BCC and SCC patients had higher levels of IL-27 in their sera compared to controls (P=0.002 and P=0.033; respectively). However, these levels were not different among SCC and BCC patients. According to our results, it seems that IL-27 is involved in antitumor immune responses in NMSCs. On the other hand, these observations might be indicative of this cytokine involvement in NMSC tumorigenesis and progression. Therefore, administration of this cytokine for therapeutic purposes in patients with such conditions should be erred on the side of caution.

Deficiency of IL-18 Aggravates Esophageal Carcinoma Through Inhibiting IFN-γ Production by CD8+T Cells and NK Cells

To investigate the potential role of interleukin-18 (IL-18) in immunomodulation during tumorigenesis of esophageal carcinoma and elucidate the underlying molecular mechanism, we employed IL-18 knockout mice for this purpose. Carcinogen 4-nitroquinoline 1-oxide (4NQO) was administrated in drinking water to induce occurrence of esophageal squamous cell carcinoma (ESCC). T cell activation as indicated by the surface CD molecules was analyzed with flow cytometry. The serous content of interferon-γ (IFN-γ) along with other cytokines was determined by inflammatory human cytokine cytometric bead array. The cytotoxicity assay was performed by co-culture of tumor cells with immune cells and relative cell viability was determined by lactate dehydrogenase (LDH) assay. Apoptotic cells were stained with Annexin-V/propidium iodide (PI) and analyzed by flow cytometry. Cell proliferation was measured with Cell Counting Kit-8 (CCK-8) assay. Our data demonstrated that deficiency of IL-18 promoted the progression and development of 4NQO-induced ESCC. Loss of IL-18 suppressed the activation of T cells in the esophagus. Deficiency of IL-18 inhibited the IFN-γ production by CD8⁺ T cells and natural killer (NK) cells. Absence of IL-18 inhibited the cytotoxicity of CD8⁺ T cells and NK cell in vitro. Moreover, deficiency of IL-18 promoted the apoptosis of CD8⁺ T cells and inhibited the proliferation of CD8⁺ T cells in vitro. Our data elucidated the immunomodulatory role of IL-18 during tumorigenesis of ESCC, whose deficiency compromised antitumor immunity and contributed to immune escape of esophageal carcinoma. Our results also indicated the therapeutic potential of exogenous IL-18 against ESCC, which warrants further investigations.

Proteomic analysis uncovers common effects of IFN-γ and IL-27 on the HLA class I antigen presentation machinery in human cancer cells

IL-27, a member of the IL-12-family of cytokines, has shown anti-tumor activity in several pre-clinical models due to anti-proliferative, anti-angiogenic and immune-enhancing effects. On the other hand, IL-27 demonstrated immune regulatory activities and inhibition of auto-immunity in mouse models. Also, we reported that IL-27, similar to IFN-γ, induces the expression of IL-18BP, IDO and PD-L1 immune regulatory molecules in human cancer cells. Here, a proteomic analysis reveals that IL-27 and IFN-γ display a broad overlap of functions on human ovarian cancer cells. Indeed, among 990 proteins modulated by either cytokine treatment in SKOV3 cells, 814 showed a concordant modulation by both cytokines, while a smaller number (176) were differentially modulated. The most up-regulated proteins were common to both IFN-γ and IL-27. In addition, functional analysis of IL-27-regulated protein networks highlighted pathways of interferon signaling and regulation, antigen presentation, protection from natural killer cell-mediated cytotoxicity, regulation of protein polyubiquitination and proteasome, aminoacid catabolism and regulation of viral protein levels.

Importantly, we found that IL-27 induced HLA class I molecule expression in human cancer cells of different histotypes, including tumor cells showing very low expression. IL-27 failed only in a cancer cell line bearing a homozygous deletion in the B2M gene. Altogether, these data point out to a broad set of activities shared by IL-27 and IFN-γ, which are dependent on the common activation of the STAT1 pathway. These data add further explanation to the anti-tumor activity of IL-27 and also to its dual role in immune regulation.

IL-27 mediates HLA class I up-regulation, which can be inhibited by the IL-6 pathway, in HLA-deficient Small Cell Lung Cancer cells

Background

Recently, immunotherapy with anti-PD-1 antibodies has shown clinical benefit in recurrent Small Cell Lung Cancer (SCLC). Since anti-PD-1 re-activates anti-tumor Cytotoxic T Lymphocyte (CTL) responses, it is crucial to understand the mechanisms regulating HLA class I, and PD-L1 expression in HLA-negative SCLC. Here we addressed the role of IL-27, a cytokine related to both IL-6 and IL-12 families.

Methods

The human SCLC cell lines NCI-N592, -H69, -H146, -H446 and -H82 were treated in vitro with different cytokines (IL-27, IFN-γ, IL-6 or a soluble IL-6R/IL-6 chimera [sIL-6R/IL-6]) at different time points and analyzed for tyrosine-phosphorylated STAT proteins by Western blot, for surface molecule expression by immunofluorescence and FACS analyses or for specific mRNA expression by QRT-PCR. Relative quantification of mRNAs was calculated by the ΔΔCT method. The Student’s T test was used for the statistical analysis of experimental replicates.

Results

IL-27 triggered STAT1/3 phosphorylation and up-regulated the expression of surface HLA class I antigen and of TAP1 and TAP2 mRNA in four out of five SCLC cell lines tested. The IL-27-resistant NCI-H146 cells showed up-regulation of HLA class I by IFN-γ. IFN-γ also induced expression of PD-L1 in SCLC cells, while IL-27 was less potent in this respect. IL-27 failed to activate STAT1/3 phosphorylation in NCI-H146 cells, which display a low expression of the IL-27RA and GP130 receptor chains. As GP130 is shared in IL-27R and IL-6R complexes, we assessed its functionality in response to sIL-6R/IL-6. sIL-6R/IL-6 failed to trigger STAT1/3 signaling in NCI-H146 cells, suggesting low GP130 expression or uncoupling from signal transduction. Although both sIL-6R/IL-6 and IL-27 triggered STAT1/3 phosphorylation, sIL-6R/IL-6 failed to up-regulate HLA class I expression, in relationship to the weak activation of STAT1. Finally sIL-6R/IL-6 limited IL-27-effects, particularly in NCI-H69 cells, in a SOCS3-independent manner, but did not modify IFN-γ induced HLA class I up-regulation.

Conclusions

In conclusion, IL-27 is a potentially interesting cytokine for restoring HLA class I expression for SCLC combined immunotherapy purposes. However, the concomitant activation of the IL-6 pathway may limit the IL-27 effect on HLA class I induction but did not significantly alter the responsiveness to IFN-γ.

Electronic supplementary material

The online version of this article (10.1186/s13046-017-0608-z) contains supplementary material, which is available to authorized users.

Dual Roles of IL-27 in Cancer Biology and Immunotherapy

IL-27 is a pleiotropic two-chain cytokine, composed of EBI3 and IL-27p28 subunits, which is structurally related to both IL-12 and IL-6 cytokine families. IL-27 acts through a heterodimer receptor consisting of IL-27Rα (WSX1) and gp130 chains, which mediate signaling predominantly through STAT1 and STAT3. IL-27 was initially reported as an immune-enhancing cytokine that supports CD4+ T cell proliferation, T helper (Th)1 cell differentiation, and IFN-γ production, acting in concert with IL-12. However, subsequent studies demonstrated that IL-27 displays complex immune-regulatory functions, which may result in either proinflammatory or anti-inflammatory effects in relationship to the biological context and experimental models considered. Several pieces of evidence, obtained in preclinical tumor models, indicated that IL-27 has a potent antitumor activity, related not only to the induction of tumor-specific Th1 and cytotoxic T lymphocyte (CTL) responses but also to direct inhibitory effects on tumor cell proliferation, survival, invasiveness, and angiogenic potential. Nonetheless, given its immune-regulatory functions, the effects of IL-27 on cancer may be dual and protumor effects may also occur. Here, we will summarize IL-27 biological activities and its functional overlaps with the IFNs and discuss its dual role in tumors in the light of potential applications to cancer immunotherapy.

IL-27 induces the expression of IDO and PD-L1 in human cancer cells

IL-27 is a member of the IL-12 family that is produced by macrophages and dendritic cells. IL-27 inhibits the growth and invasiveness of different cancers and therefore represents a potential anti-tumor agent. By contrast, it may exert immune-regulatory properties in different biological systems. We reported that IL-27 induces the expression of the IL-18 inhibitor IL-18BP, in human Epithelial Ovarian Cancer (EOC) cells, thus potentially limiting the immune response. Here, we tested whether IL-27 may modulate other immune-regulatory molecules involved in EOC progression, including Indoleamine 2,3-dioxygenase (IDO) and Programmed Death-Ligand (PD-L)1. IDO and PD-L1 were not constitutively expressed by EOC cells in vitro, but IL-27 increased their expression through STAT1 and STAT3 tyrosine phosphorylation. Differently, cells isolated from EOC ascites showed constitutive activation of STAT1 and STAT3 and IDO expression. These findings, together with the expression of IL-27 in scattered leukocytes in EOC ascites and tissues, suggest a potential role of IL-27 in immune-regulatory networks of EOC. In addition, IL-27 induced IDO or PD-L1 expression in monocytes and in human PC3 prostate and A549 lung cancer cells. A current paradigm in tumor immunology is that tumor cells may escape from immune control due to “adaptive resistance” mediated by T cell-secreted IFN-γ, which induces PD-L1 and IDO expression in tumor cells. Our present data indicate that also IL-27 has similar activities and suggest that the therapeutic use of IL-27 as anti-cancer agent may have dual effects, in some tumors.

IL-18BP is decreased in osteoporotic women: Prevents Inflammasome mediated IL-18 activation and reduces Th17 differentiation

IL-18BP is a natural antagonist of pro-inflammatory IL-18 cytokine linked to autoimmune disorders like rheumatoid arthritis. However, its role in post menopausal osteoporosis is still unknown. In this study, we investigated the role of IL-18BP on murine osteoblasts, its effect on osteoblasts-CD4+ T cells and osteoblasts-CD11b+ macrophage co-culture. mIL-18BPd enhances osteoblast differentiation and inhibits the activation of NLRP3 inflammasome and caspase-1 which process IL-18 to its active form. Using estrogen deficient mice, we also determined the effect of mIL-18BP on various immune and skeletal parameters. Ovariectomized mice treated with mIL-18BPd exhibited decrease in Th17/Treg ratio and pro-inflammatory cytokines. mIL-18BPd treatment restored trabecular microarchitecture, preserved cortical bone parameters likely attributed to an increased number of bone lining cells and reduced osteoclastogenesis. Importantly, these results were corroborated in female osteoporotic subjects where decreased serum IL-18BP levels and enhanced serum IL-18 levels were observed. Our study forms a strong basis for using humanized IL-18BP towards the treatment of postmenopausal osteoporosis.

Glycoproteomic study reveals altered plasma proteins associated with HIV elite suppressors

HIV elite suppressors (ES) or controllers are individuals achieving control of viremia by their natural immunological mechanisms without highly active antiretroviral therapy (HAART). Study of the mechanisms responsible for the immunological suppression of viremia in ES may lead to the detection of individuals with ES and the effective control of HIV infection. We hypothesize that plasma glycoproteins play essential roles in the immune system of ES since plasma proteins are critical and highly relevant in anti-viral immunity and most plasma proteins are glycoproteins. To examine glycoproteins associated with ES, plasma samples from ES individuals (n=20), and from individuals on HAART (n=20), with AIDS (n=20), and no HIV infection (n=10) were analyzed by quantitative glycoproteomics. We found that a number of glycoproteins changed between ES versus HAART, AIDS and HIV- individuals. In sharp contrast, the level of plasma glycoproteins in the HAART cohort showed fewer changes compared with AIDS and HIV- individuals. These results showed that although both ES and HAART effectively suppress viremia, ES appeared to profoundly affect immunologically relevant glycoproteins in plasma as consequence of or support for anti-viral immunity. Bioinformatic analysis revealed that altered proteins in ES plasma were mainly associated with inflammation. This analysis suggests that overlapping, while distinguishable, glycoprotein profiles for inflammation and immune activation appeared to be present between ES and non-ES (HAART+AIDS) cohorts, indicating different triggers for inflammation and immune activation between natural and treatment-related viral suppression.