FOXP3+ regulatory T cells and the immune escape in solid tumours

Circular RNAs: key players in tumor immune evasion

Immune responses against tumor antigens play a role in confining tumor growth. In response, cancer cells developed several mechanisms to bypass or defeat these anti-tumor immune responses-collectively referred to as "tumor immune evasion". Recent studies have shown that a group of non-coding RNAs, namely circRNAs affect several aspects of tumor immune evasion through regulation of activity of CD8 + T cells, regulatory T cells, natural killer cells, cytokine-induced killer cells or other immune cells. Understanding the role of circRNAs in this process facilitate design of novel therapies for enhancing the anti-tumor capacity of immune system. This review provides an outline of different roles of circRNAs in the tumor immune evasion.

Prognostic role of tumor-infiltrating lymphocytes in gastric cancer: A systematic review and meta-analysis

BACKGROUND

To analyze the relationship between tumor-infiltrating lymphocytes (TILs) subtypes and infiltration locations and the prognosis of gastric cancer (GC) patients.

METHODS

Eligible articles were obtained through systematic retrieval and rigorous screening, collecting study information and extracting hazard ratio (HR), 95 % confidence interval (CI) for pooled analyses of disease-free survival (DFS) and overall survival (OS).

RESULTS

Higher CD4+ TILs were correlated with favorable OS (HR=0.79, 95 %CI: 0.66-0.94, P = 0.009), the similar results were observed in tumor center and in infiltration margin. Higher CD8+ TILs prolonged DFS (HR=0.69, 95 %CI: 0.51-0.95, P = 0.02) and OS (HR=0.96, 95 %CI: 0.94-0.99, P = 0.006); For OS, tumor center and infiltration margin groups showed positive results. Neither the overall analysis nor the subgroup analyses indicated that the level of FOXP3+ TILs was associated with prognosis (DFS: HR=0.89, 95 %CI: 0.66-1.19, P = 0.42; OS: HR=0.98, 95 %CI: 0.85-1.13, P = 0.75). Pooled results revealed that higher CD3+ TILs were correlated with favorable DFS (HR=0.69, 95 %CI: 0.56-0.84, P = 0.0003) but not OS (HR=1.00, 95 %CI: 0.99-1.01, P = 0.48).

CONCLUSIONS

High infiltrating CD3+, CD4+, CD8+ T cells prolong survival, and FOXP3+ subset is not related to prognosis in GC. For CD4+ and CD8+, positive correlations between the infiltration level and OS were present in tumor center and infiltration margin groups.

Single-cell spatial mapping reveals alteration of cell type composition and tissue microenvironment during early colorectal cancer formation

Colorectal cancer (CRC) is the third leading cause of cancer mortality in the United States. Familial adenomatous polyposis (FAP) is a hereditary syndrome that raises the risk of developing CRC, with total colectomy as the only effective prevention. Even though FAP is rare (0.5% of all CRC cases), this disease model is well suited for studying the early stages of malignant transformation as patients form many polyps reflective of pre-cancer states. In order to spatially profile and analyze the pre-cancer and tumor microenvironment, we have performed single-cell multiplexed imaging for 52 samples: 12 normal mucosa,16 FAP mucosa,18 FAP polyps, 2 FAP adenocarcinoma, and 4 sporadic colorectal cancer (CRCs) using Co-detection by Indexing (CODEX) imaging platform. The data revealed significant changes in cell type composition occurring in early stage polyps and during the malignant transformation of polyps to CRC. We observe a decrease in CD4+/CD8+ T cell ratio and M1/M2 macrophage ratio along the FAP disease continuum. Advanced dysplastic polyps show a higher population of cancer associated fibroblasts (CAFs), which likely alter the pre-cancer microenvironment. Within polyps and CRCs, we observe strong nuclear expression of beta-catenin and higher number neo-angiogenesis events, unlike FAP mucosa and normal colon counterparts. We identify an increase in cancer stem cells (CSCs) within the glandular crypts of the FAP polyps and also detect Tregs, tumor associated macrophages (TAMs) and vascular endothelial cells supporting CSC survival and proliferation. We detect a potential immunosuppressive microenvironment within the tumor 'nest' of FAP adenocarcinoma samples, where tumor cells tend to segregate and remain distant from the invading immune cells. TAMs were found to infiltrate the tumor area, along with angiogenesis and tumor proliferation. CAFs were found to be enriched near the inflammatory region within polyps and CRCs and may have several roles in supporting tumor growth. Neighborhood analyses between adjacent FAP mucosa and FAP polyps show significant differences in spatial location of cells based on functionality. For example, in FAP mucosa, naive CD4+ T cells alone tend to localize near the fibroblast within the stromal compartment. However, in FAP polyp, CD4+T cells colocalize with the macrophages for T cell activation. Our data are expected to serve as a useful resource for understanding the early stages of neogenesis and the pre-cancer microenvironment, which may benefit early detection, therapeutic intervention and future prevention.

Regulatory T-cells: The Face-off of the Immune Balance

Regulatory T-cells (Tregs) play a crucial role in maintaining immune homeostasis, ensuring a balanced immune response. Tregs primarily operate in an antigen-specific fashion, facilitated by their distinct distribution within discrete niches. Tregs have been studied extensively, from their point of origin in the thymus origin to their fate in the periphery or organs. Signals received from antigen-presenting cells (APCs) stimulate Tregs to dampen inflammation. Almost all tumors are characterized by a pathological abundance of immune suppression in their microenvironment. Conversely, the lack thereof proves detrimental to immunological disorders. Achieving a balanced expression of Tregs in relation to other immune compartments is important in establishing an effective and adaptable immune tolerance towards cancer cells and autoantigens. In the context of cancer, it is essential to decrease the frequency of Tregs to overcome tumor suppression. A lower survival rate is associated with the presence of excessive exhausted effector immune cells and an increased frequency of regulatory cells. However, when it comes to treating graft rejection and autoimmune diseases, the focus lies on immune tolerance and the transfer of Tregs. Here, we explore the complex mechanisms that Tregs use in human disease to balance effector immune cells.

Biochemical investigation of FOXP3 genetic polymorphism and its association with biochemical parameters in pre-eclampsia patients

This study addresses the pivotal question of the association between FOXP3 gene polymorphism and pre-eclampsia (PE), employing the Tetra ARMS PCR method for analysis. PE, a multifaceted disorder marked by hypertension and organ dysfunction during pregnancy, led to an exploration of FOXP3 due to its integral role in immune regulation and its implication in various autoimmune and inflammatory disorders. The primary objective was to discern the relationship between FOXP3 gene polymorphism (rs2232365) and the risk of PE. Recruiting 200 PE patients and 100 healthy pregnant women as controls, genomic DNA was extracted from peripheral blood samples, and FOXP3 promoter region polymorphism was meticulously examined using the Tetra ARMS PCR method. The results revealed significant differences in FOXP3 gene polymorphism between PE patients and healthy controls. Specifically, certain alleles and genotypes were more frequent in PE patients, suggesting a potential genetic predisposition to this disorder. Our findings showed that rs2232365 A/G variant was found to be associated with PE under the overdominance model [OR=1.89, CI 95%= 0.99-3.60, P<0.05]. The heterozygous genotype (A/G) of FOXP3 (rs2232365) was associated with increasing the level of clinical and biochemical markers in mild and severe PE patients when compared to controls. Thus, the FOXP3 (rs2232365) A/G variant can be considered a substantial risk factor for PE.

Non-classical action of Ku70 promotes Treg suppressive function through a FOXP3-dependent mechanism in lung adenocarcinoma

Ku70, a DNA repair protein, binds to the damaged DNA ends and orchestrates the recruitment of other proteins to facilitate repair of DNA double-strand breaks. Besides its essential role in DNA repair, several studies have highlighted non-classical functions of Ku70 in cellular processes. However, its function in immune homeostasis and anti-tumor immunity remains unknown. Here, we discovered a marked association between elevated Ku70 expression and unfavorable prognosis in lung adenocarcinoma, focusing specifically on increased Ku70 levels in tumor-infiltrated Treg cells. Using a lung-colonizing tumor model of in mice with Treg-specific Ku70 deficiency, we demonstrated that deletion of Ku70 in Treg cells led to a stronger anti-tumor response and slower tumor growth due to impaired immune-suppressive capacity of Treg cells. Furthermore, we confirmed that Ku70 played a critical role in sustaining the suppressive function of human Treg cells. We found that Ku70 bound to FOXP3 and occupied FOXP3-bound genomic sites to support its transcriptional activities. These findings not only unveil a non-homologous end joining (NHEJ)-independent role of Ku70 crucial for Treg suppressive function, but also underscore the potential of targeting Ku70 as an effective strategy in cancer therapy, aiming to both restrain cancer cells and enhance pulmonary anti-tumor immunity.

A Bioinformatics Investigation of Hub Genes Involved in Treg Migration and Its Synergistic Effects, Using Immune Checkpoint Inhibitors for Immunotherapies

This study aimed to identify hub genes involved in regulatory T cell (Treg) function and migration, offering insights into potential therapeutic targets for cancer immunotherapy. We performed a comprehensive bioinformatics analysis using three gene expression microarray datasets from the GEO database. Differentially expressed genes (DEGs) were identified to pathway enrichment analysis to explore their functional roles and potential pathways. A protein-protein interaction network was constructed to identify hub genes critical for Treg activity. We further evaluated the co-expression of these hub genes with immune checkpoint proteins (PD-1, PD-L1, CTLA4) and assessed their prognostic significance. Through this comprehensive analysis, we identified CCR8 as a key player in Treg migration and explored its potential synergistic effects with ICIs. Our findings suggest that CCR8-targeted therapies could enhance cancer immunotherapy outcomes, with breast invasive carcinoma (BRCA) emerging as a promising indication for combination therapy. This study highlights the potential of CCR8 as a biomarker and therapeutic target, contributing to the development of targeted cancer treatment strategies.

Radiomics Features on Enhanced Computed Tomography Predict FOXP3 Expression and Clinical Prognosis in Patients with Head and Neck Squamous Cell Carcinoma

Forkhead box P3 (FOXP3) has been identified as a novel molecular marker in various types of cancer. The present study assessed the expression of FOXP3 in patients with head and neck squamous cell carcinoma (HNSCC) and its potential as a clinical prognostic indicator, and developed a radiomics model based on enhanced computed tomography (CT) imaging. Data from 483 patients with HNSCC were downloaded from the Cancer Genome Atlas for FOXP3 prognostic analysis and enhanced CT images from 139 patients included in the Cancer Imaging Archives, which were subjected to the maximum relevance and minimum redundancy and recursive feature elimination algorithms for radiomics feature extraction and processing. Logistic regression was used to build a model for predicting FOXP3 expression. A prognostic scoring system for radiomics score (RS), FOXP3, and patient clinicopathological factors was established to predict patient survival. The area under the receiver operating characteristic (ROC) curve (AUC) and calibration curve and decision curve analysis (DCA) were used to evaluate model performance. Furthermore, the relationship between FOXP3 and the immune microenvironment, as well as the association between RS and immune checkpoint-related genes, was analyzed. Results of analysis revealed that patients with HNSCC and high FOXP3 mRNA expression exhibited better overall survival. Immune infiltration analysis revealed that FOXP3 had a positive correlation with CD4 + and CD8 + T cells and other immune cells. The 8 best radiomics features were selected to construct the radiomics model. In the FOXP3 expression prediction model, the AUC values were 0.707 and 0.702 for the training and validation sets, respectively. Additionally, the calibration curve and DCA demonstrated the positive diagnostic utility of the model. RS was correlated with immune checkpoint-related genes such as ICOS, CTLA4, and PDCD1. A predictive nomogram was established, the AUCs were 0.87, 0.787, and 0.801 at 12, 24, and 36 months, respectively, and DCA demonstrated the high clinical applicability of the nomogram. The enhanced CT radiomics model can predict expression of FOXP3 and prognosis in patients with HNSCC. As such, FOXP3 may be used as a novel prognostic marker to improve individualized clinical diagnosis and treatment decisions.

Elesclomol Loaded Copper Oxide Nanoplatform Triggers Cuproptosis to Enhance Antitumor Immunotherapy

The induction of cuproptosis, a recently identified form of copper-dependent immunogenic cell death, is a promising approach for antitumor therapy. However, sufficient accumulation of intracellular copper ions (Cu2+) in tumor cells is essential for inducing cuproptosis. Herein, an intelligent cuproptosis-inducing nanosystem is constructed by encapsulating copper oxide (CuO) nanoparticles with the copper ionophore elesclomol (ES). After uptake by tumor cells, ES@CuO is degraded to release Cu2+ and ES to synergistically trigger cuproptosis, thereby significantly inhibiting the tumor growth of murine B16 melanoma cells. Moreover, ES@CuO further promoted cuproptosis-mediated immune responses and reprogrammed the immunosuppressive tumor microenvironment by increasing the number of tumor-infiltrating lymphocytes and secreted inflammatory cytokines. Additionally, combining ES@CuO with programmed cell death-1 (PD-1) immunotherapy substantially increased the antitumor efficacy in murine melanoma. Overall, the findings of this study can lead to the use of a novel strategy for cuproptosis-mediated antitumor therapy, which may enhance the efficacy of immune checkpoint inhibitor therapy.

FOXP3: A Player of Immunogenetic Architecture in Lung Cancer

The transcription factor forkhead box protein 3 (FOXP3) is considered to be a prominent component of the immune system expressed in regulatory T cells (Tregs). Tregs are immunosuppressive cells that regulate immune homeostasis and self-tolerance. FOXP3 was originally thought to be a Tregs-specific molecule, but recent studies have pinpointed that FOXP3 is expressed in a diversity of benign tumors and carcinomas. The vast majority of the data have shown that FOXP3 is correlated with an unfavorable prognosis, although there are some reports indicating the opposite function of this molecule. Here, we review recent progress in understanding the FOXP3 role in the immunogenetic architecture of lung cancer, which is the leading cause of cancer-related death. We discuss the prognostic significance of tumor FOXP3 expression, tumor-infiltrating FOXP3-lymphocytes, tumor FOXP3 in tumor microenvironments and the potential of FOXP3-targeted therapy.

Regulatory T cells in lung disease and transplantation

Pulmonary disease can refer to the disease of the lung itself or the pulmonary manifestations of systemic diseases, which are often connected to the malfunction of the immune system. Regulatory T (Treg) cells have been shown to be important in maintaining immune homeostasis and preventing inflammatory damage, including lung diseases. Given the increasing amount of evidence linking Treg cells to various pulmonary conditions, Treg cells might serve as a therapeutic strategy for the treatment of lung diseases and potentially promote lung transplant tolerance. The most potent and well-defined Treg cells are Foxp3-expressing CD4+ Treg cells, which contribute to the prevention of autoimmune lung diseases and the promotion of lung transplant rejection. The protective mechanisms of Treg cells in lung disease and transplantation involve multiple immune suppression mechanisms. This review summarizes the development, phenotype and function of CD4+Foxp3+ Treg cells. Then, we focus on the therapeutic potential of Treg cells in preventing lung disease and limiting lung transplant rejection. Furthermore, we discussed the possibility of Treg cell utilization in clinical applications. This will provide an overview of current research advances in Treg cells and their relevant application in clinics.

Metabolic regulation of forkhead box P3 alternative splicing isoforms and their impact on health and disease

Forkhead Box P3 (FOXP3) is crucial for the development and suppressive function of human regulatory T cells (Tregs). There are two predominant FOXP3 splicing isoforms in healthy humans, the full-length isoform and the isoform lacking exon 2, with different functions and regulation mechanisms. FOXP3 splicing isoforms show distinct abilities in the cofactor interaction and the nuclear translocation, resulting in different effects on the differentiation, cytokine secretion, suppressive function, linage stability, and environmental adaptation of Tregs. The balance of FOXP3 splicing isoforms is related to autoimmune diseases, inflammatory diseases, and cancers. In response to environmental challenges, FOXP3 transcription and splicing can be finely regulated by T cell antigen receptor stimulation, glycolysis, fatty acid oxidation, and reactive oxygen species, with various signaling pathways involved. Strategies targeting energy metabolism and FOXP3 splicing isoforms in Tregs may provide potential new approaches for the treatment of autoimmune diseases, inflammatory diseases, and cancers. In this review, we summarize recent discoveries about the FOXP3 splicing isoforms and address the metabolic regulation and specific functions of FOXP3 splicing isoforms in Tregs.

Postoperative Changes in Systemic Immune Tolerance Following Major Oncologic versus Minor Maxillofacial Surgery

BACKGROUND

There is increasing evidence of the benefits of adjuvant and neoadjuvant immunotherapy in the treatment of solid malignancies like oral squamous cell carcinoma (OSCC). To optimize (neo-)adjuvant treatment, the systemic immunomodulatory effects of tumor surgery itself need to be considered. Currently, there is little evidence on the immunological effects of major surgery, such as free microvascular flap reconstruction. The current study aims to analyze how and to what extent maxillofacial surgery affects systemic parameters of immune tolerance.

METHODS

A total of 50 peripheral whole blood samples from patients (Group 1 (G1) = extensive OSCC surgery; Group 2 (G2) = free flap reconstruction without persistent malignant disease; Group 3 (G3) = minor maxillofacial surgery) undergoing surgery were included for real-time quantitative polymerase chain reaction (RT-qPCR) to examine changes in mRNA expression of the biomarkers IL-6, IL-10, FOXP3, and PD-L1. Blood samples were taken immediately before and after surgery as well as on the second, fourth, and tenth postoperative days. Differences in mRNA expression between groups and time points were calculated using statistical tests, including Mann-Whitney U-test and Pearson correlation analysis.

RESULTS

Comparing postoperative expression of G1 and G3, there was a significantly higher PD-L1 expression (p = 0.015) in G1 compared to G3 and a significantly lower IL-6 (p = 0.001) and FOXP3 (p = 0.016) expression. Interestingly, IL-10 expression was higher pre- (0.05) and postoperative (p < 0.001) in G1 compared to G3. Additionally, in G1, there was a significant overexpression of IL-10 post-surgery compared to the preoperative value (p = 0.03) and a downregulated expression of FOXP3 between pre- and 2 d post-surgery (p = 0.04). Furthermore, there was a significant correlation between the duration of surgery and the perioperative expression changes of the analyzed biomarkers. As the duration of surgery increased, the expression of IL-10 and PD-L1 increased, and the expression of IL-6 and FOXP3 decreased.

CONCLUSION

Extensive surgery in OSCC patients is associated with a transient shift toward postoperative systemic immune tolerance compared with patients undergoing minor surgery. However, even extensive surgery causes no signs of long-lasting systemic immunosuppression. The degree of immune tolerance that occurred was associated with the duration of surgery. This supports efforts to minimize the duration of surgery.