IL-33 in the tumor microenvironment is associated with the accumulation of FoxP3-positive regulatory T cells in human esophageal carcinomas

Progress in investigating the relationship between Schlafen5 genes and malignant tumors

The Schlafen5(SLFN5)gene belongs to the third group of the Schlafen protein family. As a tumor suppressor gene, SLFN5 plays a pivotal role in inhibiting tumor growth, orchestrating cell cycle regulation, and modulating the extent of cancer cell infiltration and metastasis in various malignancies. However, the high expression of SLFN 5 in some tumors was positively correlated with lymph node metastasis, tumor stage, and tumor grade. This article endeavors to elucidate the reciprocal relationship between the SLFN5 gene and malignant tumors, thereby enhancing our comprehension of the intricate mechanisms underlying the SLFN5 gene and its implications for the progression, invasive potential, and metastatic behavior of malignant tumors. At the same time, this paper summarizes the basis of SLFN 5 as a new biomarker of tumor diagnosis and prognosis, and provides new ideas for the target treatment of tumor.

Interleukin-33: Friend or Foe in Gastrointestinal Tract Cancers?

Accumulating evidence suggests that Interleukin-33 (IL-33), a member of the IL-1 family, has crucial roles in tissue homeostasis and repair, type 2 immunity, inflammation, and viral infection. IL-33 is a novel contributing factor in tumorigenesis and plays a critical role in regulating angiogenesis and cancer progression in a variety of human cancers. The partially unraveled role of IL-33/ST2 signaling in gastrointestinal tract cancers is being investigated through the analysis of patients' samples and by studies in murine and rat models. In this review, we discuss the basic biology and mechanisms of release of the IL-33 protein and its involvement in gastrointestinal cancer onset and progression.

IL-33-expressing microvascular endothelial cells in human esophageal squamous cell carcinoma: Implications for pathological features and prognosis

Accumulating evidence suggests that interleukin (IL)-33 plays a critical role in regulating angiogenesis and cancer progression. In this study, we characterized the pathological importance of IL-33 deployed by tumor microvascular endothelial cells (ECs) in human esophageal squamous cell carcinoma (ESCC). The expression of IL-33 in microvascular ECs in 80 cases of ESCC was examined with immunohistochemistry (IHC) and double immunofluorescence. IHC results showed that strong IL-33-immunoreactivity (IR) in microvessels, which were confirmed to be ECs by double immunofluorescence staining with IL-33/CD31 antibodies. Moreover, high proliferative activity was shown in IL-33-positive ECs, and the IL-33 functional receptor ST2 was expressed in microvascular ECs. Clinicopathological analysis revealed that IL-33-positive microvessel density (MVD) was positively correlated with node involvement in patients with ESCC. A log rank test showed a highly significant inverse correlation between the densities of IL-33-positive MVDs and overall survival rate, and patients with higher IL-33-positive MVDs tended to have a lower survival rate (both p < 0.05). Therefore, we concluded that IL-33 deployed by microvascular ECs correlates with advanced pathological features and the long-term survival rate, which provides new insights into the regulatory mechanisms of tumor angiogenesis in the tumor microenvironment and might serve as a promising target in patients with ESCC.

Investigation on the regulatory T cells signature and relevant Foxp3/STAT3 axis in esophageal cancer

BACKGROUND

Regulatory T cells (Tregs) have an important role in accelerating the immunosuppression of tumor. Tregs regulation is a hopeful strategy to improve the dismal prognosis of Esophageal cancer (EC), while its mechanisms have not yet been fully clarified.

METHODS

To characterize the role of Tregs in EC, we comprehensively explored its prognostic value, clinical pathology partnership, related biological functions and potential mechanisms at transcriptome level. Through the integrated analysis of GEO and TCGA datasets, we comprehensively evaluated the Tregs infiltration patterns in EC patients. The correlation between Tregs infiltration and genomic characteristics, as well as biological functions were analyzed by a variety of computational algorithms.

RESULTS

We observed that Tregs were significantly upregulated in EC and involved in various immune processes. According to TCGA and GEO transcriptional classification schemes, Tregs specific genes were observed to be highly expressed in tumor samples, as well as were closely associated with poor prognosis and worse clinical outcomes. In addition, EC patients can be stratified into high-risk and low-risk immune subgroups according to Tregs/macrophages infiltration level, and the results showed significant differences in tumor development, biological processes and probe gene expression pattern. The multi-variate analysis revealed that the interaction between STAT3 and Foxp3 was a potential prognostic signature of Tregs in EC, especially the modulation effect of STAT3 on Foxp3 expression, which has not been well studied in EC. We also identified that STAT3 and Foxp3 expression presented a high accuracy in predicting Tregs infiltration level in EC patients (AUC: 0.817; 95% CI: 0.756-0.878).

CONCLUSIONS

Our results revealed that Tregs have the potential to predict prognosis and tumor deterioration in EC patients. A comprehensive landscape of Tregs regulation mechanisms will help us interpret the immunosuppression of tumor microenvironment (TME) and novel strategies for EC immunotherapy.

Endothelial cells-directed angiogenesis in colorectal cancer: Interleukin as the mediator and pharmacological target

Enhanced angiogenesis is a cancer hallmark and critical for colorectal cancer (CRC) invasion and metastasis. Upon exposure to proangiogenic factors, therefore, targeting tumor-associated proangiogenic factors/receptors hold great promise as a therapeutic modality to treat CRC, particularly metastatic CRC. Accumulating evidence from numerous studies suggests that tumor endothelial cells (ECs) are not only the target of proangiogenic factors, but also function as the cellular source of proangiogenic factors. Studies showed that ECs can produce different proangiogenic factors to participate in the regulation of angiogenesis process, in which ECs-derived interleukins (ILs) show a potential stimulatory effect on angiogenesis via either an direct action on their receptors expressed on progenitor of ECs or an indirect way through enhanced production of other proangiogenic factors. Although a great deal of attention is given to the effects of tumor-derived and immune cell-derived ILs, few studies describe the potential effects of vascular ECs-derived ILs on the tumor angiogenesis process. This review provides an updated summary of available information on proangiogenic ILs, such as IL-1, IL-6, IL-8, IL-17, IL-22, IL-33, IL-34, and IL-37, released by microvascular ECs as potential drivers of the tumor angiogenesis process and discusses their potential as a novel candidate for antiangiogenic target for the treatment of CRC patients.

Increased expression of ST2 on regulatory T cells is associated with cancer associated fibroblast-derived IL-33 in laryngeal cancer

Interleukin (IL)- 33 plays an essential role in regulatory T cell (Treg)-mediated immunosuppression in cancers and underlies the crosstalk between Tregs and the tumor microenvironment. However, the phenotypic characteristics of subset Tregs modulated by IL-33 and its association with the tumor microenvironment are not fully understood. This study aimed to examine the expression of ST2, the receptor of IL-33, on Tregs in tumors and to evaluate their association with cancer associated fibroblasts (CAFs) and reciprocal influences on the prognosis of laryngeal cancer. Our results showed that increased numbers of Tregs were found in laryngeal tumor tissues. Tregs in stromal IL-33-positive tumor tissues demonstrated significantly higher expression of ST2 than those in IL-33^- or adjacent nontumor tissues. ST2-expressing Tregs exhibited upregulation of Ki67 and CTLA4 compared with their ST2^- negative counterparts. Furthermore, IL-33 in the tumor microenvironment was mainly derived from fibroblasts. ST2 expression on Tregs was correlated with the number of IL-33-positive CAFs. High ST2 expression on Tregs, combined high ST2 on Tregs and the presence of IL-33 expressing CAFs was associated with worse survival outcomes in laryngeal cancer. This study indicated that increased expression of ST2 on Tregs is associated with microenvironmental IL-33 signaling derived from CAFs in laryngeal cancer, unraveling the special role of Tregs and fibroblasts in modulating IL-33/ST2 involved immune-evasive tumor microenvironment.

The Role of Tumor Microenvironment in Invasion and Metastasis of Esophageal Squamous Cell Carcinoma

Esophageal squamous cell carcinoma (ESCC) is one of the most common cancers in the world, with a high rate of morbidity. The invasion and metastasis of ESCC is the main reason for high mortality. More and more evidence suggests that metastasized cancer cells require cellular elements that contribute to ESCC tumor microenvironment (TME) formation. TME contains many immune cells and stromal components, which are critical to epithelial–mesenchymal transition, immune escape, angiogenesis/lymphangiogenesis, metastasis niche formation, and invasion/metastasis. In this review, we will focus on the mechanism of different microenvironment cellular elements in ESCC invasion and metastasis and discuss recent therapeutic attempts to restore the tumor-suppressing function of cells within the TME. It will represent the whole picture of TME in the metastasis and invasion process of ESCC.

Associations of interleukin-4 and interleukin-4 receptor loci with esophageal squamous cell carcinoma susceptibility

Some functional polymorphisms in immune-regulating genes could affect the development of esophageal squamous cell carcinoma (ESCC). We enrolled 721 patients with ESCC and 1,208 healthy controls to explore the roles of rs2227282 (C > G) and rs2243283 (C > G) loci in the interleukin-4 (IL4) gene and rs1801275 loci in the interleukin-4 receptor (IL4R) gene for the occurrence of ESCC. As for IL4, the single nucleotide polymorphism rs2227282 (C > G) conferred an overall decreased risk for ESCC (adjusted P = 0.005, power = 0.816 in GG vs. CC genetic models). A stratification analysis of IL4 rs2227282 (C > G) and rs2243283 (C > G) and IL4R rs1801275 (A > G) loci with the ESCC risk revealed that the IL4 rs2243283 (C > G) polymorphism was a protective factor for the susceptibility to ESCC in some subgroups (women: power = 0.932 in CG vs. CC and 0.956 in CG/GG vs. CC; subjects aged ≥63 years: power = 0.844 in CG/GG vs. CC; never-smokers: power = 0.893 in CG vs. CC and 0.882 in CG/GG vs. CC; never-drinkers: power = 0.904 in CG vs. CC and 0.862 in CG/GG vs. CC). We also investigated the association of IL4 rs2227282 and rs2243283 and IL4R rs1801275 loci with the lymph node status. However, a null relationship was found. In conclusion, the present study highlighted that IL4 rs2227282 (C > G) and rs2243283 (C > G) loci are protective factors for the occurrence of ESCC.

Oesophageal squamous cell carcinoma-associated IL-33 rewires macrophage polarization towards M2 via activating ornithine decarboxylase

Background

The tumour microenvironment primarily constitutes macrophages in the form of an immunosuppressive M2 phenotype, which promotes tumour growth. Thus, the development of methodologies to rewire M2‐like tumour‐associated macrophages (TAMs) into the M1 phenotype, which inhibits tumour growth, might be a critical advancement in cancer immunotherapy research.

Methods

The expressions of IL‐33 and indicators related to macrophage polarization in oesophageal squamous cell carcinoma (ESCC) tissues and peripheral blood mononuclear cell (PBMC)–derived macrophages were determined. Inhibition of ornithine decarboxylase (ODC) with small interfering RNA was used to analyse the phenotype of macrophage polarization and polyamine secretory signals. CCK‐8, wound‐healing and Transwell assays were used to detect the proliferation and migration of ECA109 cells in vitro. The tumour xenograft assay in nude mice was used to examine the role of IL‐33 in ESCC development in vivo.

Results

This study showed the substantially elevated IL‐33 expression in ESCC tissues compared with the normal tissues. Additionally, enhanced infiltration of M2‐like macrophages into the ESCC tumour tissue was also observed. We observed a strong correlation between the IL‐33 levels and the infiltration of M2‐like macrophages in ESCC tumours locally. Mechanistically, IL‐33 induces M2‐like macrophage polarization by activating ODC, a key enzyme that catalyses the synthesis of polyamines. Inhibition of ODC suppressed M2‐like macrophage polarization. Finally, in vivo, we confirmed that IL‐33 promotes tumour progression.

Conclusions

This study revealed an oncogenic role of IL‐33 by actively inducing M2‐like macrophage differentiation; thus, contributing to the formation of an immunosuppressive ESCC tumour microenvironment. Thus, IL‐33 could act as a novel target for cancer immunotherapies.

Tumor-Infiltrating Regulatory T-cell Accumulation in the Tumor Microenvironment Is Mediated by IL33/ST2 Signaling

Regulatory T cells (Treg) are enriched in the tumor microenvironment (TME) and suppress antitumor immunity; however, the molecular mechanism underlying the accumulation of Tregs in the TME is poorly understood. In various tumor models, tumor-infiltrating Tregs were highly enriched in the TME and had significantly higher expression of immune checkpoint molecules. To characterize tumor-infiltrating Tregs, we performed bulk RNA sequencing (RNA-seq) and found that proliferation-related genes, immune suppression-related genes, and cytokine/chemokine receptor genes were upregulated in tumor-infiltrating Tregs compared with tumor-infiltrating CD4+Foxp3- conventional T cells or splenic Tregs from the same tumor-bearing mice. Single-cell RNA-seq and T-cell receptor sequencing also revealed active proliferation of tumor infiltrating Tregs by clonal expansion. One of these genes, ST2, an IL33 receptor, was identified as a potential factor driving Treg accumulation in the TME. Indeed, IL33-directed ST2 signaling induced the preferential proliferation of tumor-infiltrating Tregs and enhanced tumor progression, whereas genetic deletion of ST2 in Tregs limited their TME accumulation and delayed tumor growth. These data demonstrated the IL33/ST2 axis in Tregs as one of the critical pathways for the preferential accumulation of Tregs in the TME and suggests that the IL33/ST2 axis may be a potential therapeutic target for cancer immunotherapy.

The Contradictory Role of Interleukin-33 in Immune Cells and Tumor Immunity

Interleukin (IL)-33 is a member of the IL-1 superfamily and is a crucial cytokine playing the role of a dual-function molecule. IL-33 mediates its function by interacting with its receptor suppression of tumorigenicity 2 (ST2), which is constitutively expressed on T helper (Th)1 cells, Th2 cells, and other immune cells. Previously, we summarized findings on IL-33 and performed an intensive study of the correlation between IL-33 and tumor. IL-33 enables anti-tumor immune responses through Th1 cells and natural killer (NK) cells and plays a role in tumor immune escape in cancers via Th2 cells and regulatory T cells. Herein, we discuss the contradictory role of IL-33 in immune cells in different cancer, and our summaries may be helpful for better understanding of the development of research on IL-33 and tumor immunity.

Esophageal Microenvironment: From Precursor Microenvironment to Premetastatic Niche

Esophageal cancer (EC) is the sixth most deadly cancer, and its incidence is still increasing year by year. Although the researches on the molecular mechanisms of EC have been widely carried out and incremental progress has been made, its overall survival rate is still low. There is cumulative evidence showing that the esophageal microenvironment plays a vital role in the development of EC. In precancerous lesions of the esophagus, high-risk environmental factors can promote the development of precancerous lesions by inducing the production of inflammatory factors and the recruitment of immune cells. In the tumor microenvironment, tumor-promoting cells can inhibit anti-tumor immunity and promote tumor progression through a variety of pathways, such as bone marrow-derived suppressor cells (MDSCs), tumor-associated fibroblasts (CAFs), and regulatory T cells (Tregs). The formation of extracellular hypoxia and acidic microenvironment and the change of extracellular matrix stiffness are also important factors affecting tumor progression and metastasis. Simultaneously, primary tumor-derived cytokines and bone marrow-derived immune cells can also promote the formation of pre-metastasis niche of EC lymph nodes, which are beneficial to EC lymph node metastasis. Further research on the specific mechanism of these processes in the occurrence, development, and metastasis of each EC subtype will support us to grasp the overall pre-cancerous prevention, targeted treatment, and metastatic assessment of EC.

ST2 and regulatory T cells in the colorectal adenoma/carcinoma microenvironment: implications for diseases progression and prognosis

ST2 (also known as IL1RL1) is the critical functional receptor for interleukin (IL)-33 in stimulating regulatory T cell (Treg) expansion and function in physiological and pathological conditions. We examined the correlation between ST2 cell expression and FoxP3 positive Tregs in both colorectal adenoma and cancer (CRC) microenvironment by real-time PCR, immunohistochemistry (IHC) and double immunofluorescences. The clinicopathological and prognostic significance of cellular ST2-positive cells and FoxP3-positive Tregs in patients with adenoma and CRC were evaluated. Real-time PCR results revealed increased expression levels of ST2 and FoxP3 mRNAs in both adenoma and CRC tissues as compared with control tissues. IHC analysis confirmed increased densities of ST2-positive cells in both the adenoma/CRC epithelium and stroma, which show a close positive linear association with the densities of FoxP3-positive Tregs in respective compartments. Pathological feature analysis showed that densities of ST2-positive cells in the tumor stroma were notably associated with degree of dysplastic grading in patients with adenoma, and disease stages and lymph node metastasis in patients with CRC. Kaplan-Meier survival curves suggested that CRC patients with high densities of ST2-positive cells in the stroma tend to have a shorter overall survival. We therefore concluded that increased densities of ST2-postive cells relate to Treg accumulation within the adenoma/CRC microenvironment, suggesting the IL-33/ST2 pathway as a potential contributor for immunosuppressive milieu formation that impact disease stage and prognosis in patients with CRC.

Tumoral Expression of CD166 in Human Esophageal Squamous Cell Carcinoma: Implications for Cancer Progression and Prognosis

Accumulating data showed that cancer stem cells (CSCs) identified by cell surface markers contribute to the initiation, progression, and prognosis of human cancers. In this study, the expression of CSC candidates CD166, CD44, and Lgr5 in 65 cases of esophageal squamous cell carcinoma (ESCC) and 16 cases of control esophageal tissues were examined with immunohistochemistry (IHC). The correlation between tumoral expression levels of these CSC candidates and clinicopathological variables was analyzed. IHC results showed that the expression of CD166 in esophageal control tissues was completely negative, but it was in 87.69% (57/65) ESCC tissues. The expression of CD44 and Lgr5 did not differ between esophageal control tissues and ESCC tissues (p > 0.05). In addition, there were not correlations found among the expression levels of CD166, CD44, and Lgr5 in ESCC tissues. Clinicopathological analysis revealed that the tumoral expression level of CD166 correlated with lymph node involvement and TNM staging in patients with ESCC, and lower tumoral expression of CD44 was found in patients with advanced TNM staging. Kaplan-Meier survival curves suggested that expression level of CD166 appeared to have a negative impact on overall survival rate after surgery in patients with ESCC. Such impact was not found in other two CSC candidates. The authors therefore conclude that CD166 is a potential prognostic biomarker and correlates with advanced progression features in patients with ESCC.