IL-33 Induces Sema4A Expression in Dendritic Cells and Exerts Antitumor Immunity

Integrative analysis of semaphorins family genes in colorectal cancer: implications for prognosis and immunotherapy

Background

Semaphorins (SEMAs), originally identified as axon guidance factors, have been found to play crucial roles in tumor growth, invasiveness, neoangiogenesis, and the modulation of immune responses. However, the prognostic value of SEMA-related genes in colorectal cancer (CRC) remains unclear.

Methods

We applied a novel machine learning framework that incorporated 10 machine learning algorithms and their 101 combinations to construct a SEMAs-related score (SRS). Multi-omics analysis was performed, including single-cell RNA sequencing (scRNA-seq), and spatial transcriptome (ST) to gain a more comprehensive understanding of the SRS. A series of cell experiments were conducted to prove the impact of key genes on CRC biological behavior.

Result

A consensus SRS was finally constructed based on a 101-combination machine learning computational framework, demonstrating outstanding performance in predicting overall survival. Moreover, distinct biological functions, mutation burden, immune cell infiltration, and immunotherapy response were observed between the high- and low-SRS groups. scRNA-seq and ST demonstrated unique cellular heterogeneity in CRC. We observed that SRS-high and SRS-low malignant epithelial cells exhibit different biological characteristics. High SRS malignant epithelial cells interact with myeloid and endothelial cells via SPP1 and COL4A2-ITGAV-ITGB8 pathways, respectively. Low SRS cells engage with myeloid and endothelial cells through MIF and JAG1-NOTCH4 pathways. Additionally, knocking down SEMA4C significantly inhibits the proliferation and invasion of CRC cells, while promoting apoptosis in vitro.

Conclusion

SRS could serve as an effective tool to predict survival and identify potential patients benefiting from immunotherapy in CRC. It also reveals tumor heterogeneity and provides valuable biological insights in CRC.

IL-21 and IL-33 May Be Effective Biomarkers to Predict the Efficacy of PD-1 Monoclonal Antibody for Advanced Cholangiocarcinoma

Background and Objective: Treatment options for patients with advanced biliary tract cancer (BTC) are limited. The programmed cell death protein-1 (PD-1) inhibitors may have synergistic effects with chemotherapy. Therefore, the aim of our study was to provide real-world data on treatment outcomes in BTC patients receiving chemotherapy alone versus a combination of chemotherapy and PD-1 inhibitors. Additionally, we explored potential markers predictive of PD-1 inhibitor efficacy in this combined therapy. Methods: We conducted a review of patients at Changzhou First People's Hospital who received PD-1 inhibitors in combination with chemotherapy or chemotherapy alone as first-line treatment for advanced BTC. The primary endpoints of the study were progression-free survival (PFS) and overall survival (OS). Kaplan-Meier survival curves and the log-rank test were used to analyze the data. Immunohistochemistry showed the expression of interleukin-21 (IL-21), interleukin-33 (IL-33), and Eomes in the tumor tissue of patients who received PD-1 inhibitors in combination with chemotherapy. Results: The study enrolled 61 patients receiving PD-1 inhibitors combined with chemotherapy and 65 receiving chemotherapy alone. The median OS and PFS for patients receiving PD-1 inhibitors in combination with chemotherapy were 11.7 and 6.7 months, respectively. These durations were significantly longer than those for chemotherapy alone: OS of 10.3 months (95% CI: 0.16-0.21, p = 0.031) and PFS of 5.3 months (95% Confidence interval (CI) 0.25-0.32, p = 0.018). High IL-21 expression or low IL-33 expression in tumor tissue correlated with better response rates to chemotherapy combined with PD-1 inhibitors. Conclusions: Combining PD-1 inhibitors with chemotherapy shows good antitumor activity, making it an effective way to treat BTC. The expression profiles of IL-21 and IL-33 hold promise as potential markers for guiding the chemotherapy combined with immunotherapy in BTC patients.

Downregulation of semaphorin 4A in keratinocytes reflects the features of non-lesional psoriasis

Psoriasis is a multifactorial disorder mediated by IL-17-producing T cells, involving immune cells and skin-constituting cells. Semaphorin 4A (Sema4A), an immune semaphorin, is known to take part in T helper type 1/17 differentiation and activation. However, Sema4A is also crucial for maintaining peripheral tissue homeostasis and its involvement in skin remains unknown. Here, we revealed that while Sema4A expression was pronounced in psoriatic blood lymphocytes and monocytes, it was downregulated in the keratinocytes of both psoriatic lesions and non-lesions compared to controls. Imiquimod application induced more severe dermatitis in Sema4A knockout (KO) mice compared to wild-type (WT) mice. The naïve skin of Sema4A KO mice showed increased T cell infiltration and IL-17A expression along with thicker epidermis and distinct cytokeratin expression compared to WT mice, which are hallmarks of psoriatic non-lesions. Analysis of bone marrow chimeric mice suggested that Sema4A expression in keratinocytes plays a regulatory role in imiquimod-induced dermatitis. The epidermis of psoriatic non-lesion and Sema4A KO mice demonstrated mTOR complex 1 upregulation, and the application of mTOR inhibitors reversed the skewed expression of cytokeratins in Sema4A KO mice. Conclusively, Sema4A-mediated signaling cascades can be triggers for psoriasis and targets in the treatment and prevention of psoriasis.

Unveiling the multifaceted antitumor effects of interleukin 33

Interleukin 33 (IL-33), once predominantly recognized for its pro-tumoral activities, has emerged as a multifunctional cytokine with antitumor properties. IL-33 pleiotropic activities include activation of Th1 CD4+ T cells, CD8+ T cells, NK cells, dendritic cells, eosinophils, as well as type 2 innate lymphoid cells. Regarding this immunomodulatory activity, IL-33 demonstrates synergistic interactions with various cancer therapies, including immune checkpoint blockade and chemotherapy. Combinatorial treatments leveraging IL-33 exhibit enhanced antitumor efficacy across different tumor models, promising novel avenues for cancer therapy. Despite its antitumor effects, the complex interplay of IL-33 within the tumor microenvironment underscores the need for further investigation. Understanding the mechanisms underlying IL-33's dual role as both a promoter and inhibitor of tumor progression is essential for refining therapeutic strategies and fully realizing its potential in cancer immunotherapy. This review delves into the intricate landscape of IL-33 effects within the tumor microenvironment, highlighting its pivotal role in orchestrating immune responses against cancer.

Semaphorins in tumor microenvironment: Biological mechanisms and therapeutic progress

Hallmark features of the tumor microenvironment include immune cells, stromal cells, blood vessels, and extracellular matrix (ECM), providing a conducive environment for the growth and survival of tumors. Recent advances in the understanding of cancer biology have highlighted the functional role of semaphorins (SEMAs). SEMAs are a large and diverse family of widely expressed secreted and membrane-binding proteins, which were initially implicated in axon guidance and neural development. However, it is now clear that they are widely expressed beyond the nervous system and participate in regulating immune responses and cancer progression. In fact, accumulating evidence disclosed that different SEMAs can either stimulate or restrict tumor progression, some of which act as important regulators of tumor angiogenesis. Conversely, limited information is known about the functional relevance of SEMA signals in TME. In this setting, we systematically elaborate the role SEMAs and their major receptors played in characterized components of TME. Furthermore, we provide a convergent view of current SEMAs pharmacological progress in clinical treatment and also put forward their potential application value and clinical prospects in the future.

Semaphorin4A promotes lung cancer by activation of NF-κB pathway mediated by PlexinB1

Background

Lung cancer (LC) is the most prevalent cancer with a poor prognosis. Semaphorin4A (Sema4A) is important in many physiological and pathological processes. This study aimed to explore the role and mechanism of Sema4A in LC.

Methods

Firstly, Sema4A expression was analyzed by the available dataset and detected in human normal bronchial epithelial cell line (HBE) and LC cell line (NCI-H460). Then, LC cells were transfected with Sema4A siRNA, and the cells were stimulated by PlexinB1, PlexinB2, PlexinD1 blocking antibodies, IgG antibody, BAY 11-7082 (an inhibitor for NF-κB pathway) and Sema4A-Fc protein, alone or in combination. After transfection, PlexinB1 mRNA expression was analyzed. Next, the biological functions, including proliferative, migratory, invasive abilities and viability of the cells were detected by colony formation, scratch, Transwell and MTT assays, respectively. NF-κB, Stat3 and MAPK protein expressions were determined by western blot. Furthermore, the secretion of IL-6 in LC cells was tested by ELISA.

Results

Sema4A was highly expressed in LC tissues and cells, could activate the NF-κB pathway and upregulate PlexinB1 mRNA expression. Furthermore, we observed that Sema4A knockdown suppressed the biological functions of NCI-H460 cells, while Sema4A-Fc protein reversed the situation. However, Sema4A-induced biological functions and activation in the NF-κB pathway were inhibited by PlexinB1 blocking antibody. Consistently, Sema4A promoted IL-6 production, which was down-regulated by PlexinB1 blocking antibody and BAY 11-7082.

Conclusions

Sema4A may facilitate LC development via the activation of the NF-κB pathway mediated by PlexinB1, suggesting that Sema4A would be a novel therapeutic target for LC treatment.

Tumor-derived semaphorin 4A improves PD-1-blocking antibody efficacy by enhancing CD8+ T cell cytotoxicity and proliferation

Immune checkpoint inhibitors (ICIs) have caused revolutionary changes in cancer treatment, but low response rates remain a challenge. Semaphorin 4A (Sema4A) modulates the immune system through multiple mechanisms in mice, although the role of human Sema4A in the tumor microenvironment remains unclear. This study demonstrates that histologically Sema4A-positive non-small cell lung cancer (NSCLC) responded significantly better to anti-programmed cell death 1 (PD-1) antibody than Sema4A-negative NSCLC. Intriguingly, SEMA4A expression in human NSCLC was mainly derived from tumor cells and was associated with T cell activation. Sema4A promoted cytotoxicity and proliferation of tumor-specific CD8⁺ T cells without terminal exhaustion by enhancing mammalian target of rapamycin complex 1 and polyamine synthesis, which led to improved efficacy of PD-1 inhibitors in murine models. Improved T cell activation by recombinant Sema4A was also confirmed using isolated tumor-infiltrating T cells from patients with cancer. Thus, Sema4A might be a promising therapeutic target and biomarker for predicting and promoting ICI efficacy.

Design of a potential Sema4A-based multi-epitope vaccine to combat triple-negative breast cancer: an immunoinformatic approach

Immunotherapy is revamping the therapeutic strategies for TNBC owing to its higher mutational burden and tumour-associated antigens. One of the most intriguing developments in cancer immunotherapy is the focus on peptide-based cancer vaccines. Thus, the current work aims to develop an efficient peptide-based vaccine against TNBC that targets Sema4A, which has recently been identified as a major regulator of TNBC progression. Initially, the antigenic peptides derived from Sema4A were determined and evaluated based on their capability to provoke immunological responses. The assessed epitopes were then linked with a suitable adjuvant (RpfB and RpfE) and appropriate linkers (AAY, GPGPG, KK and EAAAK) to preclude junctional immunogenicity. Eventually, docking and dynamics simulations are performed against TLR-2, TLR-4, TLR-7 and TLR-9 to assess the interaction between the vaccine construct and TLR receptors, as the TLR signalling pathway is critical in the host immune response. The developed vaccine was then exposed to in silico cloning and immune simulation analysis. The findings suggest that the designed vaccine could potentially evoke significant humoral and cellular immune responses in the intended organism. Considering these outcomes, the final multi-epitope vaccine could be employed to serve as an effective choice for TNBC management and may open new avenues for further studies.

Dual Immune Regulatory Roles of Interleukin-33 in Pathological Conditions

Interleukin-33 (IL-33), a member of the IL-1 cytokine family and a multifunctional cytokine, plays critical roles in maintaining host homeostasis and in pathological conditions, such as allergy, infectious diseases, and cancer, by acting on multiple types of immune cells and promoting type 1 and 2 immune responses. IL-33 is rapidly released by immune and non-immune cells upon stimulation by stress, acting as an “alarmin” by binding to its receptor, suppression of tumorigenicity 2 (ST2), to trigger downstream signaling pathways and activate inflammatory and immune responses. It has been recognized that IL-33 displays dual-functioning immune regulatory effects in many diseases and has both pro- and anti-tumorigenic effects, likely depending on its primary target cells, IL-33/sST2 expression levels, cellular context, and the cytokine microenvironment. Herein, we summarize our current understanding of the biological functions of IL-33 and its roles in the pathogenesis of various conditions, including inflammatory and autoimmune diseases, infections, cancers, and cases of organ transplantation. We emphasize the nature of context-dependent dual immune regulatory functions of IL-33 in many cells and diseases and review systemic studies to understand the distinct roles of IL-33 in different cells, which is essential to the development of more effective diagnoses and therapeutic approaches for IL-33-related diseases.

Semaphorins as Potential Immune Therapeutic Targets for Cancer

Semaphorins are a large class of secreted or membrane-bound molecules. It has been reported that semaphorins play important roles in regulating several hallmarks of cancer, including angiogenesis, metastasis, and immune evasion. Semaphorins and their receptors are widely expressed on tumor cells and immune cells. However, the biological role of semaphorins in tumor immune microenvironment is intricate. The dysregulation of semaphorins influences the recruitment and infiltration of immune cells, leading to abnormal anti-tumor effect. Although the underlying mechanisms of semaphorins on regulating tumor-infiltrating immune cell activation and functions are not fully understood, semaphorins can notably be promising immunotherapy targets for cancer.

Inhalant Mammal-Derived Lipocalin Allergens and the Innate Immunity

A major part of important mammalian respiratory allergens belongs to the lipocalin family of proteins. By this time, 19 respiratory mammalian lipocalin allergens have been registered in the WHO/IUIS Allergen Nomenclature Database. Originally, lipocalins, small extracellular proteins (molecular mass ca. 20 kDa), were characterized as transport proteins but they are currently known to exert a variety of biological functions. The three-dimensional structure of lipocalins is well-preserved, and lipocalin allergens can exhibit high amino acid identities, in several cases more than 50%. Lipocalins contain an internal ligand-binding site where they can harbor small principally hydrophobic molecules. Another characteristic feature is their capacity to bind to specific cell-surface receptors. In all, the physicochemical properties of lipocalin allergens do not offer any straightforward explanations for their allergenicity. Allergic sensitization begins at epithelial barriers where diverse insults through pattern recognition receptors awaken innate immunity. This front-line response is manifested by epithelial barrier-associated cytokines which together with other components of immunity can initiate the sensitization process. In the following, the crucial factor in allergic sensitization is interleukin (IL)-4 which is needed for stabilizing and promoting the type 2 immune response. The source for IL-4 has been searched widely. Candidates for it may be non-professional antigen-presenting cells, such as basophils or mast cells, as well as CD4+ T cells. The synthesis of IL-4 by CD4+ T cells requires T cell receptor engagement, i.e., the recognition of allergen peptides, which also provides the specificity for sensitization. Lipocalin and innate immunity-associated cell-surface receptors are implicated in facilitating the access of lipocalin allergens into the immune system. However, the significance of this for allergic sensitization is unclear, as the recognition by these receptors has been found to produce conflicting results. As to potential adjuvants associated with mammalian lipocalin allergens, the hydrophobic ligands transported by lipocalins have not been reported to enhance sensitization while it is justified to suppose that lipopolysaccharide plays a role in it. Taken together, type 2 immunity to lipocalin allergens appears to be a harmful immune response resulting from a combination of signals involving both the innate and adaptive immunities.