IL-36 Signaling in the Tumor Microenvironment

IL-36 antagonism blunts the proliferation and migration of oral squamous cell carcinoma cells

IL-36 is known to mediate inflammation and fibrosis. Nevertheless, IL-36 signalling axis has also been implicated in cancer, although understanding of exact contribution of IL-36 to cancer progression is very limited, partly due to existence of multiple IL-36 ligands with agonistic and antagonistic function. Here we explored the role of IL-36 in oral squamous cell carcinoma (OSCC). Firstly, we analyzed expression of IL-36 ligands and receptor and found that the expression of IL-36γ was significantly higher in head and neck cancer (HNSCC) than that of normal tissues, and that the high expression of IL-36γ predicted poor clinical outcomes. Secondly, we investigated the direct effect of IL-36γ on OSCC cells and found that IL-36γ stimulated proliferation of OSCC cells with high expression of IL-36R expression. Interestingly, IL-36γ also promoted migration of OSCC cells with low to high IL-36R expression. Critically, both proliferation and migration of OSCC cells induced by IL-36γ were abrogated by anti-IL-36R mAb. Fittingly, RNA sequence analysis revealed that IL-36γ regulated genes involved in cell cycle and cell division. In summary, our results showed that IL-36γ can be a tumor-promoting factor, and targeting of IL-36R signalling may be a beneficial targeted therapy for patients with abnormal IL-36 signalling.

Novel therapeutic strategies targeting myeloid-derived suppressor cell immunosuppressive mechanisms for cancer treatment

Cancer is the leading cause of death globally superseded only by cardiovascular diseases, and novel strategies to overcome therapeutic resistance against existing cancer treatments are urgently required. Myeloid-derived suppressor cells (MDSCs) are immature myeloid cells with potent immunosuppressive capacity against well-established anti-tumour effectors such as natural killer cells (NK cells) and T cells thereby promoting cancer initiation and progression. Critically, MDSCs are readily identified in almost all tumour types and human cancer patients, and numerous studies in the past decade have recognised their role in contributing to therapeutic resistance against all four pillars of modern cancer treatment, namely surgery, chemotherapy, radiotherapy and immunotherapy. MDSCs suppress anti-tumour immunity through a plethora of mechanisms including the well-characterised arginase 1 (Arg1), inducible nitric oxide synthase (iNOS) and reactive oxygen species (ROS)-mediated pathways, along with several other more recently discovered. MDSCs are largely absent in healthy homeostatic states and predominantly exist in pathological conditions, making them attractive therapeutic targets. However, the lack of specific markers identified for MDSCs to date greatly hindered therapeutic development, and currently there are no clinically approved drugs that specifically target MDSCs. Methods to deplete MDSCs clinically and inhibit their immunosuppressive function will be crucial in advancing cancer treatment and to overcome treatment resistance. This review provides a detailed overview of the current understandings behind the mechanisms of MDSC-mediated suppression of anti-tumour immunity, and discusses potential strategies to target MDSC immunosuppressive mechanisms to overcome therapeutic resistance.

The role of the interleukin-36 axis in generalized pustular psoriasis: a review of the mechanism of action of spesolimab

Generalized pustular psoriasis (GPP) is a rare, chronic, inflammatory skin disorder characterized by recurrent flares associated with skin erythema, desquamation, and widespread superficial sterile pustules, which may be severe ("lakes of pus"). Systemic symptoms are often present, including malaise, fever, and skin pain. In GPP, innate immune responses are driven by abnormal activation of the interleukin (IL)-36-chemokine-neutrophil axis and excessive neutrophil infiltration. This review highlights the IL-36 pathway in the context of the IL-1 superfamily and describes how unopposed IL-36 signaling can lead to the development of GPP. Targeted inhibition of the IL-36 receptor (IL-36R) is an attractive therapeutic strategy in the treatment of GPP, including flare prevention and sustained disease control. Spesolimab is a first-in-class, humanized, monoclonal antibody that binds specifically to the IL-36R and antagonizes IL-36 signaling. Spesolimab was approved by the US Food and Drug Administration in September 2022 to treat GPP flares in adults and was subsequently approved for GPP flare treatment in other countries across the world. Anti-IL-36R therapy, such as spesolimab, can mitigate flares and address flare prevention in GPP, presumably through rebalancing IL-36 signaling and modulating the pro-inflammatory response of the downstream effectors.

IL-36α inhibits melanoma by inducing pro-inflammatory polarization of macrophages

Interleukin-36α (IL-36α) is essential for various inflammatory conditions, such as psoriasis and rheumatoid arthritis, whereas its role in tumor immunity is unclear. In this study, it was demonstrated that IL-36α could activate the NF-κB and MAPK signaling pathways in macrophages, leading to the expression of IL-1β, IL-6, TNF-α, CXCL1, CXCL2, CXCL3, CXCL5 and iNOS. Importantly, IL-36α has significant antitumor effects, altering the tumor microenvironment and promoting the infiltration of MHC IIhigh macrophages and CD8+ T cells while decreasing the levels of monocyte myeloid-derived suppressor cells, CD4+ T cells and regulatory T cells. This ultimately results in the inhibition of tumor growth and migration. Furthermore, IL-36α synergized with the PD-L1 antibody increased the immune cells infiltration and enhanced the anti-tumor effect of the PD-L1 antibody on melanoma. Collectively, this study reveals a new role for IL-36α in promoting anti-tumor immune responses in macrophages and suggests its potential for cancer immunotherapy.

Transcriptomic and functional analyses reveal a tumour-promoting role for the IL-36 receptor in colon cancer and crosstalk between IL-36 signalling and the IL-17/ IL-23 axis

BACKGROUND

The interleukin (IL)-36 cytokines are a sub-family of the IL-1 family which are becoming increasingly implicated in the pathogenesis of inflammatory diseases and malignancies. Initial studies of IL-36 signalling in tumorigenesis identified an immune-mediated anti-tumorigenic function for these cytokines. However, more recent studies have shown IL-36 cytokines also contribute to the pathogenesis of lung and colorectal cancer (CRC).

METHODS

The aim of this study was to investigate IL-36 expression in CRC using transcriptomic datasets and software such as several R packages, Cytoscape, GEO2R and AnalyzeR. Validation of results was completed by qRT-PCR on both cell lines and a patient cohort. Cellular proliferation was assessed by flow cytometry and resazurin reduction.

RESULTS

We demonstrate that IL-36 gene expression increases with CRC development. Decreased tumoral IL-36 receptor expression was shown to be associated with improved patient outcome. Our differential gene expression analysis revealed a novel role for the IL-36/IL-17/IL-23 axis, with these findings validated using patient-derived samples and cell lines. IL-36γ, together with either IL-17a or IL-22, was able to synergistically induce different genes involved in the IL-17/IL-23 axis in CRC cells and additively induce colon cancer cell proliferation.

CONCLUSIONS

Collectively, this data support a pro-tumorigenic role for IL-36 signalling in colon cancer, with the IL-17/IL-23 axis influential in IL-36-mediated colon tumorigenesis.

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

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

Features and clinical significance of tertiary lymphoid structure in cutaneous squamous cell carcinoma

BACKGROUND

Tertiary lymphoid structure (TLS) plays an important role in anti-tumor immunity, largely reflecting the prognosis. However, its clinical implication in cutaneous squamous cell carcinoma (cSCC) remains unknown.

OBJECTIVES

To explore the features of TLS in cSCC and its association with clinicopathological characteristics.

METHODS

Two independent RNA-seq data of cSCC were used to investigate the tumor immune microenvironment, as well as TLS-related chemokines and cytokines. The density and location of TLSs were assessed in a total of 82 cSCC patients, and the clinicopathologic association was examined.

RESULTS

Bioinformatics analysis showed that a large amount of immune cell infiltration and significant up-regulation of TLS-related chemokines were observed in cSCC. Histologically, TLSs appeared as highly organized structures in 72 (87.8%) cases with different levels of density and maturation, among which 14 cases were in low-density group and 58 cases were in high-density group. Clinically, the presence of TLS was prominently associated with better degree of histopathological grades and higher level of sun exposure. Furthermore, the presence of intratumoral TLS was associated with lower lymphovascular invasion.

CONCLUSIONS

TLS is highly organized in cSCC, and the presence of TLS is a positive prognostic factor for cSCC, which will provide a theoretical basis for the future diagnostic and therapeutic value in cSCC.

The role of IL-36 subfamily in intestinal disease

Interleukin (IL)-36 is a subfamily, of the IL-1 super-family and includes IL-36α, IL-36β, IL-36γ, IL-38 and IL-36Ra. IL-36 cytokines are involved in the pathology of multiple tissues, including skin, lung, oral cavity, intestine, kidneys and joints. Recent studies suggest that IL-36 signaling regulates autoimmune disease in addition to antibacterial and antiviral responses. Most research has focused on IL-36 in skin diseases such as psoriasis, however, studies on intestinal diseases are also underway. This review outlines what is known about the bioactivity of the IL-36 subfamily and its role in the pathogenesis of intestinal diseases such as inflammatory bowel disease, colorectal cancer, gut dysbacteriosis and infection, and proposes that IL-36 may be a target for novel therapeutic strategies to prevent or treat intestinal diseases.

Gene-Edited Interleukin CAR-T Cells Therapy in the Treatment of Malignancies: Present and Future

In recent years, chimeric antigen receptor T cells (CAR-T cells) have been faced with the problems of weak proliferation and poor persistence in the treatment of some malignancies. Researchers have been trying to perfect the function of CAR-T by genetically modifying its structure. In addition to the participation of T cell receptor (TCR) and costimulatory signals, immune cytokines also exert a decisive role in the activation and proliferation of T cells. Therefore, genetic engineering strategies were used to generate cytokines to enhance tumor killing function of CAR-T cells. When CAR-T cells are in contact with target tumor tissue, the proliferation ability and persistence of T cells can be improved by structurally or inductively releasing immunoregulatory molecules to the tumor region. There are a large number of CAR-T cells studies on gene-edited cytokines, and the most common cytokines involved are interleukins (IL-7, IL-12, IL-15, IL-18, IL-21, IL-23). Methods for the construction of gene-edited interleukin CAR-T cells include co-expression of single interleukin, two interleukin, interleukin combined with other cytokines, interleukin receptors, interleukin subunits, and fusion inverted cytokine receptors (ICR). Preclinical and clinical trials have yielded positive results, and many more are under way. By reading a large number of literatures, we summarized the functional characteristics of some members of the interleukin family related to tumor immunotherapy, and described the research status of gene-edited interleukin CAR-T cells in the treatment of malignant tumors. The objective is to explore the optimized strategy of gene edited interleukin-CAR-T cell function.

Airborne particulate matter upregulates expression of early and late adhesion molecules and their receptors in a lung adenocarcinoma cell line

BACKGROUND

Epidemiological evidence associates chronic exposure to particulate matter (PM) with respiratory damage and lung cancer. Inhaled PM may induce systemic effects including inflammation and metastasis. This study evaluated whether PM induces expression of adhesion molecules in lung cancer cells promoting interaction with monocytes.

METHODS

The expression of early and late adhesion molecules and their receptors was evaluated in A549 (human lung adenocarcinoma) cells using a wide range of concentrations of PM_2.5 and PM₁₀. Then we evaluated cellular adhesion between A549 cells and U937 (human monocytes) cells after PM exposure.

RESULTS

We found higher expression of both early and late adhesion molecules and their ligands in lung adenocarcinoma cells exposed to PM_2.5 and PM₁₀ particles present in the air pollution at Mexico City from 0.03 μg/cm² with a statistically significant difference (p ≤ 0.05). PM₁₀ had stronger effect than PM_2.5. Both PM also stimulated cellular adhesion between tumor cells and monocytes.

CONCLUSIONS

This study reveals a comprehensive expression profile of adhesion molecules and their ligands upregulated by PM_2.5 and PM₁₀ in A549 cells. Additionally these particles induced cellular adhesion of lung cancer cells to monocytes. This highlights possible implications of PM in two cancer hallmarks i.e. inflammation and metastasis, underlying the high cancer mortality associated with air pollution.

STINGing the Tumor Microenvironment to Promote Therapeutic Tertiary Lymphoid Structure Development

Tertiary lymphoid structures (TLS), also known as ectopic lymphoid structures (ELS) or tertiary lymphoid organs (TLO), represent a unique subset of lymphoid tissues noted for their architectural similarity to lymph nodes, but which conditionally form in peripheral tissues in a milieu of sustained inflammation. TLS serve as regional sites for induction and expansion of the host B and T cell repertoires via an operational paradigm involving mature dendritic cells (DC) and specialized endothelial cells (i.e. high endothelial venules; HEV) in a process directed by TLS-associated cytokines and chemokines. Recent clinical correlations have been reported for the presence of TLS within tumor biopsies with overall patient survival and responsiveness to interventional immunotherapy. Hence, therapeutic strategies to conditionally reinforce TLS formation within the tumor microenvironment (TME) via the targeting of DC, vascular endothelial cells (VEC) and local cytokine/chemokine profiles are actively being developed and tested in translational tumor models and early phase clinical trials. In this regard, a subset of agents that promote tumor vascular normalization (VN) have been observed to coordinately support the development of a pro-inflammatory TME, maturation of DC and VEC, local production of TLS-inducing cytokines and chemokines, and therapeutic TLS formation. This mini-review will focus on STING agonists, which were originally developed as anti-angiogenic agents, but which have recently been shown to be effective in promoting VN and TLS formation within the therapeutic TME. Future application of these drugs in combination immunotherapy approaches for greater therapeutic efficacy is further discussed.