Inhibition of the CCR6-CCL20 axis prevents regulatory T cell recruitment and sensitizes head and neck squamous cell carcinoma to radiation therapy

Defining enteric bacterial pathogenesis using organoids: Citrobacter rodentium uses EspC, an atypical mucinolytic protease, to penetrate mouse colonic mucus

Enteric bacterial pathogens pose significant threats to human health; however, the mechanisms by which they infect the mammalian gut in the face of daunting host defenses remain to be fully defined. For the attaching and effacing (A/E) bacterial family member and murine pathogen Citrobacter rodentium, its virulence strategy appears to involve penetration of the colonic mucus barrier to reach the underlying epithelium. To better define these interactions, we grew colonoids under air-liquid interface (ALI) conditions, producing a thick mucus layer that mimicked in vivo mucus composition and glycosylation. C. rodentium's penetration of ALI-derived mucus was dramatically enhanced upon exposure to sialic acid, in concert with the secretion of two serine protease autotransporter of Enterobacteriaceae (SPATE) proteins, Pic and EspC. Despite Pic being a class II SPATE, and already recognized as a mucinase, it was EspC, a class I SPATE family member, that degraded ALI-derived mucus, despite class I SPATEs not previously shown to possess mucinase activity. Confirming this finding, E. coli DH5α carrying a plasmid that expresses C. rodentium-derived EspC was able to degrade the mucus. Moreover, recombinant EspC alone also displayed mucinolytic activity in a dose-dependent manner. Collectively, our results reveal the utility of ALI-derived mucus in modeling microbe-host interactions at the intestinal mucosal surface, as well as identify EspC as an atypical class I SPATE that shows significant mucinolytic activity toward ALI-derived mucus.

CCL20-CCR6 signaling in tumor microenvironment: Functional roles, mechanisms, and immunotherapy targeting

Chemokine CC motif ligand 20 (CCL20) is a molecule with immunomodulatory properties that is involved in the regulation of diseases such as chronic inflammation, autoimmune diseases, and cancer. It operates by binding to its specific receptor, CC chemokine receptor type 6 (CCR6), and activating a complex intracellular signaling network. Building on its established role in inflammatory diseases, recent research has expanded our understanding of CCL20 to encompass its critical contributions to the tumor microenvironment (TME), highlighting its significance in cancer progression. Numerous studies have emphasized its prominent role in regulating immune responses. Consequently, Monoclonal antibodies against CCL20 and inhibitors of CCR6 have been successfully developed to block downstream signaling, making the CCL20-CCR6 axis a promising and critical target in the TME. This offers potential immunotherapeutic strategies for cancers. In this review, we summarize the biological consequences of CCL20-CCR6 mediated signaling, its role and mechanisms in the TME, and its potential applications. We suggest that the CCL20-CCR6 axis may be a novel biomarker for tumor diagnosis and prognosis, as well as a therapeutic target in various cancers.

Radiotherapy modulates autophagy to reshape the tumor immune microenvironment to enhance anti-tumor immunity in esophageal cancer

The combination of radiotherapy and immunotherapy exerts synergistic antitumor in a range of human cancers, and also in esophageal cancer. Radiotherapy-induced tumor immune microenvironment (TIME) reprogramming is an essential basis for the synergistic antitumor between radiotherapy and immunotherapy. Radiotherapy can induce autophagy in tumor cells and immune cells of TIME, and autophagy activation is involved in the modification of immunological characteristics of TIME. The TIME landscape of esophageal cancer, especially ESCC, can be affected by radiotherapy or autophagy regulation. In this review, we depicted that local radiotherapy-induced autophagy could promote the maturation, migration, infiltration, and function of immune cells by complicated mechanisms to make TIME from immune "cold" to "hot", resulting in the synergistic antitumor of RT and IO. We argue that unraveling the relevance of radiotherapy-initiated autophagy to driving radiotherapy reprogramming TIME will open new ideas to explore new targets or more efficiently multimodal therapeutic interventions in ESCC.

Nucleic Acid Drugs in Radiotherapy

Radiotherapy remains a cornerstone of cancer treatment, using high-energy radiation to induce DNA damage in tumor cells, leading to cell death. However, its efficacy is often hindered by challenges such as radiation resistance and side effects. As a powerful class of functional molecules, nucleic acid drugs (NADs) present a promising solution to these limitations. Engineered to target key pathways like DNA repair and tumor hypoxia, NADs can enhance radiotherapy sensitivity. NADs can also serve as delivery vehicles for radiotherapy agents such as radionuclides, improving targeting accuracy and minimizing side effects. This review explores the role of NADs in optimizing radiotherapy, highlighting their mechanisms, clinical applications, and synergies with radiotherapy, ultimately offering a promising strategy for improving patient outcomes in cancer therapy.

CCL20 in the tumor microenvironment: implications for cancer progression and therapeutic approaches

Increasing knowledge of the immunosuppressive tumor microenvironment in cancer-related processes has led to the developing of novel immune-based therapies that have changed the cancer treatment paradigm. In the tumor microenvironment, the plethora of soluble factors secreted by tumor cells interacts with immune cells and non-immune components to deliver signals necessary for tumor progression. Accordingly, targeting tumor-derived factors inducing this immunosuppressive tumor microenvironment has become an appealing therapeutic potential in advancing cancer treatment. CCL20, a chemokine best known to induce leucocyte migration in response to pathological and inflammatory conditions, has been implicated in tumor proliferation, angiogenesis, metastasis, immunosuppression, and therapeutic resistance. Notably, CCL20 and its receptor CCR6 are important in tumor microenvironment interactions. This review discusses the interaction between the CCL20-CCR6 axis and the tumor microenvironment and how these interactions promote tumor progression. Also, an outline of studies utilizing CCL20 in combination with other standard cancer treatments has been shed.

Recurrent and Metastatic Head and Neck Cancer: Mechanisms of Treatment Failure, Treatment Paradigms, and New Horizons

Background: Head and neck cancer is a deadly disease with over 500,000 cases annually worldwide. Metastatic head and neck cancer accounts for a large proportion of the mortality associated with this disease. Many advances have been made in our understanding of the mechanisms of metastasis. The application of immunotherapy to locally recurrent or metastatic head and neck cancer has not only improved oncologic outcomes but has also provided valuable insights into the mechanisms of immune evasion and ultimately treatment failure. Objectives: This review paper will review our current understanding of biological mechanisms of treatment failure and metastasis. Published and ongoing clinical trials in the management of metastatic head and neck cancer will also be summarized. Methods: A narrative review was conducted to address the current understanding of the mechanisms of treatment failure and current treatment paradigms in recurrent and metastatic head and neck carcinoma. Conclusions: Our understanding of treatment failure in this disease is rapidly evolving. Immunotherapy represents a valuable new tool in the fight against recurrent and metastatic head and neck squamous cell carcinoma. Integrating patient and tumor specific data via artificial intelligence and deep learning will allow for a precision oncology approach, thereby achieving better prognostication and management of patients with this deadly disease.

Emerging combined CAR-NK cell therapies in cancer treatment: Finding a dancing partner

In recent decades, immunotherapy with chimeric antigen receptors (CARs) has revolutionized cancer treatment and given hope where other cancer therapies have failed. CAR-natural killer (NK) cells are NK cells that have been engineered ex vivo with a CAR on the cell membrane with high specificity for specific target antigens of tumor cells. The impressive results of several studies suggest that CAR-NK cell therapy has significant potential and successful performance in cancer treatment. Despite its effectiveness, CAR-NK cell therapy can have significant challenges when it comes to treating cancer. These challenges include tumor heterogeneity, antigen escape, an immunosuppressive tumor microenvironment, limited tissue migration from blood, exhaustion of CAR-NK cells, and inhibition by immunosuppressive checkpoint molecule signaling, etc. In CAR-T cell therapy, the use of combined approaches has shown encouraging outcomes for tumor regression and improved cancer treatment compared to single therapies. Therefore, to overcome these significant challenges in CAR-NK cells, innovative combination therapies of CAR-NK cells with other conventional therapies (e.g., chemotherapy and radiotherapy) or other immunotherapies are needed to counteract the above challenges and thereby increase the activity of CAR-NK cells. This review comprehensively discusses various cancer-treatment approaches in combination with CAR-NK cell therapy in the hope of providing valuable insights that may improve cancer treatment in the near future.

Tumor-infiltrating regulatory T cell: A promising therapeutic target in tumor microenvironment

ABSTRACT

Regulatory T cell (Tregs) predominantly maintain the immune balance and prevent autoimmunity via their immunosuppressive functions. However, tumor-infiltrating Tregs (TI-Tregs) may mediate tumor immune tolerance in complex tumor microenvironments, resulting in poor prognosis. Distinguishing specific TI-Treg subpopulations from peripheral Tregs and intratumoral conventional T cells (Tconvs) has recently emerged as an important topic in antitumor therapy. In this review, we summarize novel therapeutic approaches targeting both the metabolic pathways and hallmarks of TI-Tregs in preclinical and clinical studies. Although the phenotypic and functional diversity of TI-Tregs remains unclear, our review provides new insights into TI-Treg-based therapies and facilitates precision medicine for tumor treatment.

The CCR6-CCL20 Axis Promotes Regulatory T-cell Glycolysis and Immunosuppression in Tumors

Regulatory T cells (Treg) are important players in the tumor microenvironment. However, the mechanisms behind their immunosuppressive effects are poorly understood. We found that CCR6-CCL20 activity in tumor-infiltrating Tregs is associated with greater glycolytic activity and ablation of Ccr6 reduced glycolysis and lactic acid production while increasing compensatory glutamine metabolism. Immunosuppressive activity toward CD8+ T cells was abrogated in Ccr6-/- Tregs due to reduction in activation-induced glycolysis. Furthermore, Ccr6-/- mice exhibited improved survival across multiple tumor models compared to wild-type mice and Treg and CD8+ T-cell depletion abrogated the improvement. In addition, Ccr6 ablation further promoted the efficacy of anti-PD-1 therapy in a preclinical glioma model. Follow-up knockdown of Ccl20 with siRNA also demonstrated improvement in antitumor efficacy. Our results unveil CCR6 as a marker and regulator of Treg-induced immunosuppression and identify approaches to target the metabolic determinants of Treg immunosuppressive activity.

Single-cell sequencing reveals immune features of treatment response to neoadjuvant immunochemotherapy in esophageal squamous cell carcinoma

Neoadjuvant immunochemotherapy (nICT) has dramatically changed the treatment landscape of operable esophageal squamous cell carcinoma (ESCC), but factors influencing tumor response to nICT are not well understood. Here, using single-cell RNA sequencing paired with T cell receptor sequencing, we profile tissues from ESCC patients accepting nICT treatment and characterize the tumor microenvironment context. CXCL13+CD8+ Tex cells, a subset of exhausted CD8+ T cells, are revealed to highly infiltrate in pre-treatment tumors and show prominent progenitor exhaustion phenotype in post-treatment samples from responders. We validate CXCL13+CD8+ Tex cells as a predictor of improved response to nICT and reveal CXCL13 to potentiate anti-PD-1 efficacy in vivo. Post-treatment tumors from non-responders are enriched for CXCL13+CD8+ Tex cells with notably remarkable exhaustion phenotype and TNFRSF4+CD4+ Tregs with activated immunosuppressive function and a significant clone expansion. Several critical markers for therapeutic resistance are also identified, including LRRC15+ fibroblasts and SPP1+ macrophages, which may recruit Tregs to form an immunosuppressive landscape. Overall, our findings unravel immune features of distinct therapeutic response to nICT treatment, providing a rationale for optimizing individualized neoadjuvant strategy in ESCC.

Novel plasma protein biomarkers: A time-dependent predictive model for Alzheimer's disease

BACKGROUND

The accurate prediction of Alzheimer's disease (AD) is crucial for the efficient management of its progression. The objective of this research was to construct a new risk predictive model utilizing novel plasma protein biomarkers for predicting AD incidence in the future and analyze their potential biological correlation with AD incidence.

METHODS

A cohort of 440 participants aged 60 years and older from the Alzheimer's Disease Neuroimaging Initiative (ADNI) longitudinal cohort was utilized. The baseline plasma proteomics data was employed to conduct Cox regression, LASSO regression, and cross-validation to identify plasma protein signatures predictive of AD risk. Subsequently, a multivariable Cox proportional hazards model based on these signatures was constructed. The performance of the risk prediction model was evaluated using time-dependent receiver operating characteristic (t-ROC) curves and Kaplan-Meier curves. Additionally, we analyzed the correlations between protein signature expression in plasma and predicted AD risk, the time of AD onset, the expression of protein signatures in cerebrospinal fluid (CSF), the expression of CSF and plasma biomarkers, and APOE ε4 genotypes. Colocalization and Mendelian randomization analyses was conducted to investigate the association between protein features and AD risk. GEO database was utilized to analyze the differential expression of protein features in the blood and brain of AD patients.

RESULTS

We identified seven protein signatures (APOE, CGA, CRP, CCL26, CCL20, NRCAM, and PYY) that independently predicted AD incidence in the future. The risk prediction model demonstrated area under the ROC curve (AUC) values of 0.77, 0.76, and 0.77 for predicting AD incidence at 4, 6, and 8 years, respectively. Furthermore, the model remained stable in the range of the 3rd to the 12th year (ROC ≥ 0.74). The low-risk group, as defined by the model, exhibited a significantly later AD onset compared to the high-risk group (P < 0.0001). Moreover, all protein signatures exhibited significant correlations with AD risk (P < 0.001) and the time of AD onset (P < 0.01). There was no strong correlation between the protein expression levels in plasma and CSF, as well as AD CSF biomarkers. APOE, CGA, and CRP exhibited significantly lower expression levels in APOE ε4 positive individuals (P < 0.05). Additionally, colocalization analysis reveals a significant association between AD and SNP loci in APOE. Mendelian randomization analysis shows a negative correlation between NRCAM and AD risk. Transcriptomic analysis indicates a significant downregulation of NRCAM and PYY in the peripheral blood of AD patients (P < 0.01), while APOE, CGA, and NRCAM are significantly downregulated in the brains of AD patients (P < 0.0001).

CONCLUSION

Our research has successfully identified protein signatures in plasma as potential risk biomarkers that can independently predict AD onset in the future. Notably, this risk prediction model has demonstrated commendable predictive performance and stability over time. These findings underscore the promising utility of plasma protein signatures in dynamically predicting the risk of AD, thereby facilitating early screening and intervention strategies.

Overexpression of CCL-20 and CXCL-8 genes enhances tumor escape and resistance to cemiplimab, a programmed cell death protein-1 (PD-1) inhibitor, in patients with locally advanced and metastatic cutaneous squamous cell carcinoma

Cemiplimab has demonstrated relevant clinical activity in cutaneous squamous cell carcinoma (cSCC) but mechanisms of primary and acquired resistance to immunotherapy are still unknown. We collected clinical data from locally advanced and/or metastatic cSSC patients treated with cemiplimab in two Italian University centers. In addition, gene expression analysis by using Nanostring Technologies platform to evaluate 770 cancer- and immune-related genes on 20 tumor tissue samples (9 responders and 11 non-responders to cemiplimab) was performed. We enrolled 81 patients with a median age of 82 years. After 16.4 months of median follow-up, 12- and 24-months PFS were 53% and 42%, respectively; while 12- and 24-months OS were 71% and 61%, respectively. Treatment was well tolerated. Overall response rate (ORR) was 58%, with a disease control rate (DCR) of 77.8%. The difference between genes expressed in responder versus non-responder patient samples was substantial, particularly for genes involved in immune system regulation. Cemiplimab-resistant tumors were associated with over-expression of CCL-20 and CXCL-8. Cemiplimab confirmed efficacy and safety data in real-life cSCC patients. Overexpression of CCL-20 and CXCL-8 could represent biomarkers of lack of response to immunotherapy.

Immune cell topography of head and neck cancer

BACKGROUND

Approximately 50% of head and neck squamous cell carcinomas (HNSCC) recur after treatment with curative intent. Immune checkpoint inhibitors are treatment options for recurrent/metastatic HNSCC; however, less than 20% of patients respond. To increase this response rate, it is fundamental to increase our understanding of the spatial tumor immune microenvironment (TIME).

METHODS

In total, 53 HNSCC specimens were included. Using a seven-color multiplex immunohistochemistry panel we identified tumor cells, CD163+macrophages, B cells, CD8+T cells, CD4+T helper cells and regulatory T cells (Tregs) in treatment-naive surgical resection specimens (n=29) and biopsies (n=18). To further characterize tumor-infiltrating CD8+T cells, we stained surgical resection specimens (n=12) with a five-color tumor-resident panel including CD103, Ki67, CD8 and pan-cytokeratin. Secretome analysis was performed on matched tumor suspensions (n=11) to measure protein levels.

RESULTS

Based on CD8+T cell infiltrates, we identified four different immunotypes: fully infiltrated, stroma-restricted, immune-excluded, and immune-desert. We found higher cytokine levels in fully infiltrated tumors compared with other immunotypes. While the highest immune infiltrates were observed in the invasive margin for all immune cells, CD163+macrophages and Tregs had the highest tendency to infiltrate the tumor center. Within the tumor center, especially B cells stayed at the tumor stroma, whereas CD163+macrophages, followed by T cells, were more often localized within tumor fields. Also, B cells were found further away from other cells and often formed aggregates while T cells and CD163+macrophages tended to be more closely located to each other. Across resection specimens from various anatomical sites within the head and neck, oral cavity tumors exhibited the highest densities of Tregs. Moreover, the distance from B cells and T cells to tumor cells was shortest in oral cavity squamous cell carcinoma (OCSCC), suggesting more interaction between lymphocytes and tumor cells. Also, the fraction of T cells within 10 µm of CD163+macrophages was lowest in OCSCC, indicating fewer myeloid/T-cell suppressive interactions in OCSCC.

CONCLUSIONS

We comprehensively described the TIME of HNSCC using a unique data set of resection specimens. We discovered that the composition, as well as the relative localization of immune cells in the TIME, differed in distinct anatomical sites of the head and neck.

Spotlight on pro-inflammatory chemokines: regulators of cellular communication in cognitive impairment

Cognitive impairment is a decline in people's ability to think, learn, and remember, and so forth. Cognitive impairment is a global health challenge that affects the quality of life of thousands of people. The condition covers a wide range from mild cognitive impairment to severe dementia, which includes Alzheimer's disease (AD) and Parkinson's disease (PD), among others. While the etiology of cognitive impairment is diverse, the role of chemokines is increasingly evident, especially in the presence of chronic inflammation and neuroinflammation. Although inflammatory chemokines have been linked to cognitive impairment, cognitive impairment is usually multifactorial. Researchers are exploring the role of chemokines and other inflammatory mediators in cognitive dysfunction and trying to develop therapeutic strategies to mitigate their effects. The pathogenesis of cognitive disorders is very complex, their underlying causative mechanisms have not been clarified, and their treatment is always one of the challenges in the field of medicine. Therefore, exploring its pathogenesis and treatment has important socioeconomic value. Chemokines are a growing family of structurally and functionally related small (8-10 kDa) proteins, and there is growing evidence that pro-inflammatory chemokines are associated with many neurobiological processes that may be relevant to neurological disorders beyond their classical chemotactic function and play a crucial role in the pathogenesis and progression of cognitive disorders. In this paper, we review the roles and regulatory mechanisms of pro-inflammatory chemokines (CCL2, CCL3, CCL4, CCL5, CCL11, CCL20, and CXCL8) in cognitive impairment. We also discuss the intrinsic relationship between the two, hoping to provide some valuable references for the treatment of cognitive impairment.

TRIM Expression in HNSCC: Exploring the Link Between Ubiquitination, Immune Infiltration, and Signaling Pathways Through Bioinformatics

Objective

Ubiquitination is an important post-translational modification. However, the significance of the TRIM family of E3 ubiquitin ligases in head and neck squamous cell carcinoma (HNSCC) has not been determined. In this study, the roles of TRIM E3 ubiquitin ligases in lymphovascular invasion in head and neck squamous cell carcinoma (HNSCC) were evaluated.

Materials and Methods

TRIM expression and related parameters were obtained from UbiBrowser2.0, UALCAN, TIMER, TISIDB, LinkedOmics, STRING, and GeneMANIA databases. Immunohistochemistry was used to confirm their expression.

Results

TRIM2, TRIM11, TRIM28, and TRIM56 were upregulated in HNSCC with lymphovascular invasion. TRIM expression was strongly associated with immune infiltration, including key treatment targets, like PD-1 and CTL4. Co-expressed genes and possible ubiquitination substrates included tumor-related factors. The TRIMs had predicted roles in ubiquitination-related pathways and vital signaling pathways, eg, MAPK, PI3K-Akt, and JAK-STAT signaling pathways.

Conclusion

Ubiquitination mediated by four TRIMs might be involved in the regulation of tumor immunity, laying the foundation for future studies of the roles of the TRIM family on the prediction and personalized medicine in HNSCC. The four TRIMs might exert oncogenic effects by promoting lymphovascular invasion in HNSCC.

High Serum Levels of CCL20 Are Associated with Recurrence and Unfavorable Overall Survival in Advanced Melanoma Patients Receiving Immunotherapy

BACKGROUND

Immune checkpoint inhibition has revolutionized melanoma therapy, but many patients show primary or secondary resistance. Biomarkers are, therefore, urgently required to predict response prior to the initiation of therapy and to monitor disease progression.

METHODS

In this prospective study, we analyzed the serum C-C motif chemokine ligand 20 (CCL20) concentration using an enzyme-linked immunosorbent assay. Blood was obtained at baseline before the initiation of immunotherapy with anti-PD-1 monotherapy or Nivolumab and Ipilimumab in advanced melanoma patients (stages III and IV) enrolled at the University Medical Center Hamburg-Eppendorf. The CCL20 levels were correlated with clinico-pathological parameters and disease-related outcomes.

RESULTS

An increased C-C motif chemokine ligand 20 (CCL20) concentration (≥0.34 pg/mL) at baseline was associated with a significantly impaired progression-free survival (PFS) in the high-CCL20 group (3 months (95% CI: 2-6 months) vs. 11 months (95% CI: 6-26 months)) (p = 0.0033) and could be identified as an independent negative prognostic factor for PFS in univariate (Hazard Ratio (HR): 1.98, 95% CI 1.25-3.12, p = 0.004) and multivariate (HR: 1.99, 95% CI 1.21-3.29, p = 0.007) Cox regression analysis, which was associated with a higher risk than S100 (HR: 1.74). Moreover, high CCL20 levels were associated with impaired overall survival (median OS not reached for low-CCL20 group, p = 0.042) with an HR of 1.85 (95% CI 1.02-3.37, p = 0.043) in univariate analysis similar to the established prognostic marker S100 (HR: 1.99, 95% CI: 1.02-3.88, p = 0.043).

CONCLUSIONS

CCL20 may represent a novel blood-based biomarker for the prediction of resistance to immunotherapy that can be used in combination with established strong clinical predictors (e.g., ECOG performance score) and laboratory markers (e.g., S100) in advanced melanoma patients. Future prospective randomized trials are needed to establish CCL20 as a liquid biopsy-based biomarker in advanced melanoma.

PITPNC1 Suppress CD8+ T cell immune function and promote radioresistance in rectal cancer by modulating FASN/CD155

BACKGROUND

Radioresistance is a primary factor contributing to the failure of rectal cancer treatment. Immune suppression plays a significant role in the development of radioresistance. We have investigated the potential role of phosphatidylinositol transfer protein cytoplasmic 1 (PITPNC1) in regulating immune suppression associated with radioresistance.

METHODS

To elucidate the mechanisms by which PITPNC1 influences radioresistance, we established HT29, SW480, and MC38 radioresistant cell lines. The relationship between radioresistance and changes in the proportion of immune cells was verified through subcutaneous tumor models and flow cytometry. Changes in the expression levels of PITPNC1, FASN, and CD155 were determined using immunohistochemistry and western blotting techniques. The interplay between these proteins was investigated using immunofluorescence co-localization and immunoprecipitation assays. Additionally, siRNA and lentivirus-mediated gene knockdown or overexpression, as well as co-culture of tumor cells with PBMCs or CD8+ T cells and establishment of stable transgenic cell lines in vivo, were employed to validate the impact of the PITPNC1/FASN/CD155 pathway on CD8+ T cell immune function.

RESULTS

Under irradiation, the apoptosis rate and expression of apoptosis-related proteins in radioresistant colorectal cancer cell lines were significantly decreased, while the cell proliferation rate increased. In radioresistant tumor-bearing mice, the proportion of CD8+ T cells and IFN-γ production within immune cells decreased. Immunohistochemical analysis of human and animal tissue specimens resistant to radiotherapy showed a significant increase in the expression levels of PITPNC1, FASN, and CD155. Gene knockdown and rescue experiments demonstrated that PITPNC1 can regulate the expression of CD155 on the surface of tumor cells through FASN. In addition, co-culture experiments and in vivo tumor-bearing experiments have shown that silencing PITPNC1 can inhibit FASN/CD155, enhance CD8+ T cell immune function, promote colorectal cancer cell death, and ultimately reduce radioresistance in tumor-bearing models.

CONCLUSIONS

PITPNC1 regulates the expression of CD155 through FASN, inhibits CD8+ T cell immune function, and promotes radioresistance in rectal cancer.

A new target of radiotherapy combined with immunotherapy: regulatory T cells

Radiotherapy is one important treatment for malignant tumours. It is widely believed today that radiotherapy has not only been used as a local tumour treatment method, but also can induce systemic anti-tumour responses by influencing the tumour microenvironment, but its efficacy is limited by the tumour immunosuppression microenvironment. With the advancement of technology, immunotherapy has entered a golden age of rapid development, gradually occupying a place in clinical tumour treatment. Regulatory T cells (Tregs) widely distributing in the tumour microenvironment play an important role in mediating tumour development. This article analyzes immunotherapy, the interaction between Tregs, tumours and radiotherapy. It briefly introduces immunotherapies targeting Tregs, aiming to provide new strategies for radiotherapy combined with Immunotherapy.

Synergistic treatment strategy: combining CAR-NK cell therapy and radiotherapy to combat solid tumors

Immunotherapy, notably chimeric antigen receptor (CAR) modified natural killer (NK) cell therapy, has shown exciting promise in the treatment of hematologic malignancies due to its unique advantages including fewer side effects, diverse activation mechanisms, and wide availability. However, CAR-NK cell therapies have demonstrated limited efficacy against solid tumors, primarily due to challenges posed by the solid tumor microenvironment. In contrast, radiotherapy, a well-established treatment modality, has been proven to modulate the tumor microenvironment and facilitate immune cell infiltration. With these observations, we hypothesize that a novel therapeutic strategy integrating CAR-NK cell therapy with radiotherapy could enhance the ability to treat solid tumors. This hypothesis aims to address the obstacles CAR-NK cell therapies face within the solid tumor microenvironment and explore the potential efficacy of their combination with radiotherapy. By capitalizing on the synergistic advantages of CAR-NK cell therapy and radiotherapy, we posit that this could lead to improved prognoses for patients with solid tumors.

Clinicopathological characteristics and molecular analysis of lymphocyte-rich hepatocellular carcinoma

Lymphocyte-rich hepatocellular carcinoma (LR-HCC), a newly proposed subtype of HCC, is characterized with abundant lymphocyte infiltration in the tumor. LR-HCC has a relatively good prognosis and is quite rare (<1% of all HCC). We examined LR-HCC clinicopathological and molecular characteristics by analyzing 451 surgically resected HCC cases without any prior treatment history at our hospital between 2012 and 2021. Clinicopathological features of LR-HCC and other HCCs (non-LR-HCC) were compared. Neoplastic and nonneoplastic hepatocytes from LR-HCC (n = 4) were collected with a laser microdissection system; RNA was extracted, followed by microarray analysis to examine lymphocytic infiltration-related molecular targets. Immunohistochemical staining of identified molecular target was performed in LR-HCC and non-LR-HCC. CD3, CD20, and CD8 immunostaining was also performed in LR-HCCs. There were 28 cases of LR-HCC (6%). No statistically significant differences were found in clinicopathological features, except for gross type, between LR-HCC and non-LR-HCC cases. The LR-HCC 5-year survival rate was >90%. Microarray analysis revealed high CCL20 expression in LR-HCC cases; immunohistochemical study showed significantly higher CCL20 expression in LR-HCC (P < 0.01) than in non-LR-HCC. CCR6, the only CCL20 receptor, was observed in infiltrating lymphocytes and HCC cells in LR-HCC. There were significantly more CD3-positive cells than CD20-positive cells (P < 0.0001) in tumor-infiltrating lymphocytes, most of which were CD8-positive T cells. In conclusion, there were no significant differences in clinicopathological characteristics between LR-HCC and non-LR-HCC, except for gross and LR microscopic features. CCL20 expression in LR-HCC may contribute to infiltration of large numbers of CD8-positive lymphocytes.

Mechanisms of radiotherapy resistance and radiosensitization strategies for esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is the sixth most common cause of cancer-related mortality worldwide, with more than half of them occurred in China. Radiotherapy (RT) has been widely used for treating ESCC. However, radiation-induced DNA damage response (DDR) can promote the release of cytokines and chemokines, and triggers inflammatory reactions and changes in the tumor microenvironment (TME), thereby inhibiting the immune function and causing the invasion and metastasis of ESCC. Radioresistance is the major cause of disease progression and mortality in cancer, and it is associated with heterogeneity. Therefore, a better understanding of the radioresistance mechanisms may generate more reversal strategies to improve the cure rates and survival periods of ESCC patients. We mainly summarized the possible mechanisms of radioresistance in order to reveal new targets for ESCC therapy. Then we summarized and compared the current strategies to reverse radioresistance.

Establishment of a Novel Anti-Human CCR6 Monoclonal Antibody C6Mab-19 with the High Binding Affinity in Flow Cytometry

CC chemokine receptor 6 (CCR6) is a member of the G-protein-coupled receptor family that is highly expressed in B lymphocytes, effector and memory T cells, regulatory T cells, and immature dendritic cells. CCR6 has been revealed to have important functions in many pathological conditions, such as cancer, intestinal bowel disease, psoriasis, and autoimmune diseases. The only CCR6 chemokine ligand, CC motif chemokine ligand 20 (CCL20), is also involved in pathogenesis by interacting with CCR6. The CCL20/CCR6 axis is drawing attention as an attractive therapeutic target for various diseases. In this study, we developed novel monoclonal antibodies (mAbs) against human CCR6 (hCCR6) using the peptide immunization method, which are applicable to flow cytometry and immunohistochemistry. The established anti-hCCR6 mAb, clone C6Mab-19 (mouse IgG1, kappa), reacted with hCCR6-overexpressed Chinese hamster ovary-K1 (CHO/hCCR6), human liver carcinoma (HepG2), and human differentiated hepatoma (HuH-7) cells in flow cytometry. The dissociation constant (KD) of C6Mab-19 was determined as 3.0 × 10-10 M for CHO/hCCR6, 6.9 × 10-10 M for HepG2, and 1.8 × 10-10 M for HuH-7. Thus, C6Mab-19 could bind to exogenously and endogenously expressed hCCR6 with extremely high affinity. Furthermore, C6Mab-19 could stain formalin-fixed paraffin-embedded lymph node tissues from a patient with non-Hodgkin lymphoma by immunohistochemistry. Therefore, C6Mab-19 is suitable for detecting hCCR6-expressing cells and tissues and could be useful for pathological analysis and diagnosis.

Identification of the Binding Epitope of an Anti-Mouse CCR6 Monoclonal Antibody (C6Mab-13) Using 1× Alanine Scanning

CC chemokine receptor 6 (CCR6) is one of the members of the G-protein-coupled receptor (GPCR) family that is upregulated in many immune-related cells, such as B lymphocytes, effector and memory T cells, regulatory T cells, and immature dendritic cells. The coordination between CCR6 and its ligand CC motif chemokine ligand 20 (CCL20) is deeply involved in the pathogenesis of various diseases, such as cancer, psoriasis, and autoimmune diseases. Thus, CCR6 is an attractive target for therapy and is being investigated as a diagnostic marker for various diseases. In a previous study, we developed an anti-mouse CCR6 (mCCR6) monoclonal antibody (mAb), C₆Mab-13 (rat IgG₁, kappa), that was applicable for flow cytometry by immunizing a rat with the N-terminal peptide of mCCR6. In this study, we investigated the binding epitope of C₆Mab-13 using an enzyme-linked immunosorbent assay (ELISA) and the surface plasmon resonance (SPR) method, which were conducted with respect to the synthesized point-mutated-peptides within the 1-20 amino acid region of mCCR6. In the ELISA results, C₆Mab-13 lost its ability to react to the alanine-substituted peptide of mCCR6 at Asp11, thereby identifying Asp11 as the epitope of C₆Mab-13. In our SPR analysis, the dissociation constants (K_D) could not be calculated for the G9A and D11A mutants due to the lack of binding. The SPR analysis demonstrated that the C₆Mab-13 epitope comprises Gly9 and Asp11. Taken together, the key binding epitope of C₆Mab-13 was determined to be located around Asp11 on mCCR6. Based on the epitope information, C₆Mab-13 could be useful for further functional analysis of mCCR6 in future studies.

A meta-validated immune infiltration-related gene model predicts prognosis and immunotherapy sensitivity in HNSCC

BACKGROUND

Tumor microenvironment (TME) is of great importance to regulate the initiation and advance of cancer. The immune infiltration patterns of TME have been considered to impact the prognosis and immunotherapy sensitivity in Head and Neck squamous cell carcinoma (HNSCC). Whereas, specific molecular targets and cell components involved in the HNSCC tumor microenvironment remain a twilight zone.

METHODS

Immune scores of TCGA-HNSCC patients were calculated via ESTIMATE algorithm, followed by weighted gene co-expression network analysis (WGCNA) to filter immune infiltration-related gene modules. Univariate, the least absolute shrinkage and selection operator (LASSO), and multivariate cox regression were applied to construct the prognostic model. The predictive capacity was validated by meta-analysis including external dataset GSE65858, GSE41613 and GSE686. Model candidate genes were verified at mRNA and protein levels using public database and independent specimens of immunohistochemistry. Immunotherapy-treated cohort GSE159067, TIDE and CIBERSORT were used to evaluate the features of immunotherapy responsiveness and immune infiltration in HNSCC.

RESULTS

Immune microenvironment was significantly associated with the prognosis of HNSCC patients. Total 277 immune infiltration-related genes were filtered by WGCNA and involved in various immune processes. Cox regression identified nine prognostic immune infiltration-related genes (MORF4L2, CTSL1, TBC1D2, C5orf15, LIPA, WIPF1, CXCL13, TMEM173, ISG20) to build a risk score. Most candidate genes were highly expressed in HNSCC tissues at mRNA and protein levels. Survival meta-analysis illustrated high prognostic accuracy of the model in the discovery cohort and validation cohort. Higher proportion of progression-free outcomes, lower TIDE scores and higher expression levels of immune checkpoint genes indicated enhanced immunotherapy responsiveness in low-risk patients. Decreased memory B cells, CD8+ T cells, follicular helper T cells, regulatory T cells, and increased activated dendritic cells and activated mast cells were identified as crucial immune cells in the TME of high-risk patients.

CONCLUSIONS

The immune infiltration-related gene model was well-qualified and provided novel biomarkers for the prognosis of HNSCC.