IL-33 in Tumor Immunity: Nothing to Sneeze At

Prognostic significance of IL-33 and ST2 expression in head and neck squamous cell carcinoma: a systematic review

Background

Interleukin-33 (IL-33) and Suppression of tumorigenicity 2 (ST2) expression are strongly associated with tumor growth and progression in diverse cancers, indicating the possibility of targeting the IL-33/ST2 axis pathway as a favorable therapeutic approach. However, the specific implications of IL-33/ST2 expression in Head and Neck Squamous Cell Carcinoma (HNSCC) prognosis are not fully understood. Thus, there is a need for more comprehensive research to verify the tasks and clinical significance of IL-33 and ST2 in HNSCC.

Objectives

The objective of this study was to evaluate the potential of differentially expressed IL-33 and ST2 in tumor tissues that could serve as novel biomarkers in HNSCC.

Material & methods

The Web of Science, Scopus, and PubMed electronic databases were searched and analyzed from January 2013 to July 2023.

Results

Nine studies fulfilling the inclusion criteria were analyzed. These selected studies were mainly having observational analytical study design, predominantly conducted within the Southeast Asian population. IL-33, primarily located in the stroma, demonstrates enhanced expression within carcinoma-associated fibroblasts (CAFs). Overexpression of IL-33 in CAFs correlates with its expression in tumor cells, as per some of these reports. Elevated IL-33 levels in CAFs are associated with unfavorable clinical outcomes. Increased IL-33 expression is related to poor nodal metastasis-free survival, indicating an adverse prognosis in HNSCC. In HNSCC, tumor cells and regulatory T cells (Tregs) expressed ST2. The degree of ST2 expression on Tregs corresponds to the abundance of IL-33 expressing CAFs. IL-33 increases the Tregs density and amplifies their suppressive capability. Poorer survival outcomes in HNSCC are linked to elevated ST2 expression in Tregs combined with the existence of IL-33-expressing CAFs.

Conclusion

CAF-driven cancer invasiveness relies on IL-33 signaling via paracrine and autocrine pathways. IL-33 may be a prognostic biomarker and therapeutic target, aiming to improve prognosis and survival in HNSCC. The IL-33/ST2 axis significantly configures the tumor microenvironment and tumor aggressiveness in HNSCC. The role of serum IL33 and ST2 remains to be further studied in HNSCC.

Systematic Review Registration

https://www.crd.york.ac.uk/PROSPERO/i, identifier (CRD42023447963).

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSION

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

IL-33 and IL-33-derived DC-based tumor immunotherapy

Interleukin-33 (IL-33), a member of the IL-1 family, is a cytokine released in response to tissue damage and is recognized as an alarmin. The multifaceted roles of IL-33 in tumor progression have sparked controversy within the scientific community. However, most findings generally indicate that endogenous IL-33 has a protumor effect, while exogenous IL-33 often has an antitumor effect in most cases. This review covers the general characteristics of IL-33 and its effects on tumor growth, with detailed information on the immunological mechanisms associated with dendritic cells (DCs). Notably, DCs possess the capability to uptake, process, and present antigens to CD8+ T cells, positioning them as professional antigen-presenting cells. Recent findings from our research highlight the direct association between the tumor-suppressive effects of exogenous IL-33 and a novel subset of highly immunogenic cDC1s. Exogenous IL-33 induces the development of these highly immunogenic cDC1s through the activation of other ST2+ immune cells both in vivo and in vitro. Recognizing the pivotal role of the immunogenicity of DC vaccines in DC-based tumor immunotherapy, we propose compelling methods to enhance this immunogenicity through the addition of IL-33 and the promotion of highly immunogenic DC generation.

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

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

Discovery of highly immunogenic spleen-resident FCGR3+CD103+ cDC1s differentiated by IL-33-primed ST2+ basophils

Recombinant interleukin-33 (IL-33) inhibits tumor growth, but the detailed immunological mechanism is still unknown. IL-33-mediated tumor suppression did not occur in Batf3-/- mice, indicating that conventional type 1 dendritic cells (cDC1s) play a key role in IL-33-mediated antitumor immunity. A population of CD103+ cDC1s, which were barely detectable in the spleens of normal mice, increased significantly in the spleens of IL-33-treated mice. The newly emerged splenic CD103+ cDC1s were distinct from conventional splenic cDC1s based on their spleen residency, robust effector T-cell priming ability, and surface expression of FCGR3. DCs and DC precursors did not express Suppressor of Tumorigenicity 2 (ST2). However, recombinant IL-33 induced spleen-resident FCGR3+CD103+ cDC1s, which were found to be differentiated from DC precursors by bystander ST2+ immune cells. Through immune cell fractionation and depletion assays, we found that IL-33-primed ST2+ basophils play a crucial role in the development of FCGR3+CD103+ cDC1s by secreting IL-33-driven extrinsic factors. Recombinant GM-CSF also induced the population of CD103+ cDC1s, but the population neither expressed FCGR3 nor induced any discernable antitumor immunity. The population of FCGR3+CD103+ cDC1s was also generated in vitro culture of Flt3L-mediated bone marrow-derived DCs (FL-BMDCs) when IL-33 was added in a pre-DC stage of culture. FL-BMDCs generated in the presence of IL-33 (FL-33-DCs) offered more potent tumor immunotherapy than control Flt3L-BMDCs (FL-DCs). Human monocyte-derived DCs were also more immunogenic when exposed to IL-33-induced factors. Our findings suggest that recombinant IL-33 or an IL-33-mediated DC vaccine could be an attractive protocol for better tumor immunotherapy.

Using Adoptive Cellular Therapy for Localized Protein Secretion

ABSTRACT

Redirection of T cell cytotoxicity by the chimeric antigen receptor (CAR) structure may not be sufficient for optimal antitumor function in the patient tumor microenvironment. Comodifying CAR T cells to secrete different classes of proteins can be used to optimize CAR T cell function, overcome suppressive signals, and/or alter the tumor microenvironment milieu. These modifications aim to improve initial responses to therapy and enhance the durability of response. Furthermore, CAR T cells can deliver these molecules locally to the tumor microenvironment, avoiding systemic distribution. This approach has been tested in preclinical models using a variety of different classes of agonistic and antagonistic proteins, and clinical trials are currently underway to assess efficacy in patients.

The Role of Interleukin-33 in Head and Neck Squamous Cell Carcinoma Is Determined by Its Cellular Sources in the Tumor Microenvironment

Objectives

To investigate the role of interleukin-33 (IL-33) in head and neck squamous cell carcinoma (HNSCC).

Materials and Methods

RNA-seq data of 520 cases of HNSCC were retrieved from The Cancer Genome Atlas. The tumor microenvironment was deconstructed by xCell using bulk RNA-seq data. The cohort was dichotomized by the median IL-33 expression level. Immune cell components and molecular markers were compared between the high and low IL-33 groups. The prognostic value of IL-33 was evaluated by the log-rank test. Differential gene expression analysis and KEGG pathway enrichment analysis were also conducted. The relationship between the IL-33 expression level and the abundance of its potential cellular sources was evaluated by Pearson’s partial correlation test. Subgroup analysis was conducted in laryngeal, oropharyngeal, and oral cavity squamous cell carcinoma (LSCC, OPSCC, and OCSCC).

Results

The role of IL-33 in HNSCC was heterogeneous among tumors at different sites. In LSCC, IL-33 may increase the extent of malignancy of tumor cells and act as a pro-tumor factor. In OCSCC, IL-33 may play a role in orchestrating the immune responses against tumor cells and act as an antitumor factor. The role of IL-33 in OPSCC was undetermined. IL-33 in LSCC was mainly derived from endothelial cells, while IL-33 in OCSCC was mainly derived from endothelial and epithelial cells.

Conclusion

According to the different sources of IL-33 in LSCC and OCSCC, we propose a hypothesis that stroma-derived IL-33 could favor tumor progression, while epithelial-derived IL-33 could favor antitumor immune responses in HNSCC.