The Role of IL-17 in the Pathogenesis of Oral Squamous Cell Carcinoma

Inflammatory cytokines and oral cancer risk: an integrated study combining two-sample Mendelian randomization with experimental validation

OBJECTIVE

This study aimed to investigate the causal relationship between inflammatory cytokines and oral cavity cancer risk using Mendelian randomization analysis and experimental validation.

METHODS

Two-sample Mendelian randomization was conducted using summary-level genome-wide association study data on 41 inflammatory cytokines and oral cavity cancer risk in Europeans. Single nucleotide polymorphisms associated with cytokines (p < 5 × 10-6) and oral cancer were selected as instrumental variables, excluding those in linkage disequilibrium. Inverse-variance weighted analysis was used as the primary method, supplemented by MR Egger, weighted median, simple and weighted mode methods. Sensitivity analyses included heterogeneity, horizontal pleiotropy, leave-one-out, and funnel plot assessments. Multivariable MR analysis adjusted for smoking, alcohol, periodontitis and malnutrition was performed. The findings were further validated through expression analysis in TCGA database and clinical samples, as well as functional studies in oral cancer cells.

RESULTS

In univariate MR analysis, increased beta-nerve growth factor (OR: 1.53, 95% CI: 1.06-2.20), and decreased macrophage colony stimulating factor (OR: 0.87, 95% CI: 0.78-0.98) and interleukin-18 (OR: 0.80, 95% CI: 0.65-0.98) were causally associated with higher oral cancer risk. In multivariable MR analysis, the effects remained significant after adjusting for exposures. No reverse causation was found. Expression analysis revealed significant upregulation of NGF in oral cancer tissues compared to adjacent normal tissues, while CSF1 and IL-18 showed no significant differences. Functional studies demonstrated that NGF overexpression promoted cell proliferation, colony formation, invasion, and migration while inhibiting apoptosis in oral cancer cells.

CONCLUSIONS

This integrated study combining MR analysis and experimental validation provides evidence for causal effects of increased beta-nerve growth factor along with decreased macrophage colony stimulating factor and interleukin-18 on higher oral cavity cancer risk, independent of known risk factors. The oncogenic role of NGF was further confirmed through functional studies, suggesting these inflammatory cytokines may represent etiologic targets for oral cancer prevention.

Multifaceted roles of IL-17 in bone and tendon health

The interleukin-17 (IL-17) family, encompassing IL-17A to IL-17F, plays pivotal roles across various biomedical fields. IL-17A, a prominent cytokine, has garnered significant attention. However, the pathological effects of IL-17 can often be unpredictable. This review delves into the multifaceted roles of IL-17 family members in bone healing, tendon ossification, and aging. IL-17 is central in modulating the inflammatory response during bone healing, influencing osteoblast and osteoclast activities, and promoting bone regeneration. In the context of tendon ossification, IL-17 orchestrates the proliferation, differentiation, and apoptosis of fibroblasts, instigating inflammatory responses. It also impacts the functionality of tendon stem cells and the composition of the extracellular matrix, correlating with indicators of tendon senescence. By understanding these dynamic changes, we gain deeper insights into IL-17's crucial function in bone and tendon tissues, highlighting its potential in modulating inflammatory responses. As research continues to evolve, promising therapeutic interventions targeting IL-17 are on the horizon, addressing disease challenges and paving the way for new, effective treatments.

AIM2 promotes the progression of HNSCC via STAT1 mediated transcription and IL-17/MAPK signaling

Chronic inflammation has been recognized as one of the hallmarks of head and neck squamous cell carcinoma (HNSCC), Absent In Melanoma 2(AIM2) has emerged as important regulators of chronic inflammatory, and participated in initiation, progression of kinds of human cancers. Nonetheless, the biological functions and underlying mechanisms of AIM2 in HNSCC remain inadequately understood. Based on the bioinformatics analysis of public databases, we identified elevated AIM2 expression in HNSCC, which positively correlates with disease stage and HPV infection, thereby possessing both diagnostic and prognostic significance. Immunohistochemistry on clinical samples revealed that AIM2 expression was frequently upregulated in cancerous tissues compared to paracancerous tissues, exhibiting a significant association with Ki-67 expression. Modulating AIM2 expression in HNSCC cell lines through transfection with inhibitors or mimics demonstrated that ectopic AIM2 expression enhances cell growth, migration, tumorigenesis, and metastasis both in vitro and in vivo. A dual luciferase reporter assay indicated that the transcription factor STAT1 can bind directly to the AIM2 promoter region and activate its transcription. The STAT1 inhibitor, fludarabine, reduces AIM2 expression and subsequently diminishes cell proliferation. Mechanistically, AIM2 exerts its tumor-promoting effects through the IL-17-MAPK signaling pathway. Collectively, our data demonstrate that AIM2, transcriptionally activated by STAT1, exhibits oncogenic functions by promoting the IL-17-MAPK signaling pathway, suggesting that AIM2 may be a new intervention targets for the diagnostic and treatment of HNSCC.

Interleukin-6 promotes the epithelial mesenchymal transition in canine tonsillar squamous cell carcinoma cells

Canine oral squamous cell carcinoma (CoSCC) is often associated with suppurative inflammation. Metastasis of malignant tumors is one of the signs of major interest in oncology because it speaks of disease progression, where the involvement of interleukin-6 (IL-6) in cancer progression is so far unknown. Therefore, the aim of this study was the determination of the role of IL-6 in metastasis in CoSCC cells model through expression analysis of mRNA and protein using real-time PCR and western blotting and assessment of cell migration and invasion. The messenger RNA (mRNA) expression level of IL-6 was elevated in CoSCC tissues, and the IL-6 receptor protein was expressed in CoSCC cell lines. Furthermore, IL-6 levels were associated and showed negative correlation with survival time (rs = -0.92857) in dogs with tonsillar SCC. Recombinant canine IL-6 (rcIL-6) treatment promoted migration and invasion, in addition to increasing the viable cell number of the tonsillar SCC cell line (TSCCLN#6). Consistently, the protein expression of phosphorylated ERK1/2 and STAT3 and Fascin1 (FSCN1) was upregulated by treatment with rcIL-6 in a dose-dependent manner. Treatment with ERK or STAT3 inhibitors abolished the effects of rcIL-6, and the ERK inhibitor successfully downregulated the expression of FSCN1. In conclusion, IL-6 may be involved in tonsillar CoSCC invasion and metastasis through the activation of the mitogen-activated protein kinase and Janus tyrosine kinase/signal transducer and activator of transcription signaling.

Tumour-Associated Macrophages in Oral Squamous Cell Carcinoma

OBJECTIVE

Tumour-associated macrophages (TAMs) are crucial in the progression and treatment response of oral squamous cell carcinoma (OSCC). TAMs infiltrate OSCC, adopting an M2-like phenotype that promotes tumour growth, metastasis and immune suppression. The current narrative review explored the roles of TAMs in OSCC, focusing on their impact on the tumour microenvironment, invasion, metastasis, angiogenesis, immunosuppression and potential therapeutic targeting.

METHODS

A comprehensive analysis of the current literature on TAMs in OSCC was conducted. Specifically, we evaluated the biological functions of TAMs, their interactions within the tumour microenvironment, and their influence on disease progression and treatment outcomes.

RESULTS

TAMs contribute to OSCC progression by secreting cytokines, such as IL-10 and TGF-β, that inhibit effector immune cells. They facilitate angiogenesis, extracellular matrix remodelling and the epithelial-mesenchymal transition, which are essential for tumour invasion and metastasis. TAMs support cancer stem cells and recruit regulatory T cells and myeloid-derived suppressor cells, enhancing resistance to therapies. Their presence correlates with advanced OSCC stages, lymph node metastasis and poor prognosis.

CONCLUSION

TAMs regulate OSCC progression and therapy resistance. Reprogramming them to an M1-like phenotype or depleting them enhances treatments. Understanding TAM-OSCC interactions is crucial for developing interventions against their tumour-promoting functions and restoring anti-tumour immunity.

The Impact of Oral Microbiome Dysbiosis on the Aetiology, Pathogenesis, and Development of Oral Cancer

Oral squamous cell carcinoma (OSCC) is the most common head and neck cancer. Although the oral cavity is an easily accessible area for visual examination, the OSCC is more often detected at an advanced stage. The global prevalence of OSCC is around 6%, with increasing trends posing a significant health problem due to the increase in morbidity and mortality. The oral cavity microbiome has been the target of numerous studies, with findings highlighting the significant role of dysbiosis in developing OSCC. Dysbiosis can significantly increase pathobionts (bacteria, viruses, fungi, and parasites) that trigger inflammation through their virulence and pathogenicity factors. In contrast, chronic bacterial inflammation contributes to the development of OSCC. Pathobionts also have other effects, such as the impact on the immune system, which can alter immune responses and contribute to a pro-inflammatory environment. Poor oral hygiene and carbohydrate-rich foods can also increase the risk of developing oral cancer. The risk factors and mechanisms of OSCC development are not yet fully understood and remain a frequent research topic. For this reason, this narrative review concentrates on the issue of dysbiosis as the potential cause of OSCC, as well as the underlying mechanisms involved.

Astaxanthin Synergizes with Ionizing Radiation (IR) in Oral Squamous Cell Carcinoma (OSCC)

Astaxanthin (ATX) is known for its antioxidant and anti-inflammation functions yet its role in cancers requires more research. This study is aimed to reveal the potential synergetic effect of ATX with ionizing radiation (IR) in OSCC. Cell survival was measured after human OSCC cells including CAL27 and SCC9, and normal human oral keratinocytes (NHOKs) were treated with different concentrations of ATX for 24 h. Colony formation assays were performed after OSCC cells were treated with IR, ATX (20 μ M), or combined and survival fraction was analyzed. Malondialdehyde (MDA), glutathione (GSH), and intercellular iron levels were measured. Western blot method was used to measure the ferroptosis-related proteins, GPX4, SLC7A11, and ACSL4. In xenograft mice model, we evaluated the tumor volumes, tumor growth, and examined the GPX4/ACSL4 proteins in tumor tissues using Immunohistochemistry (IHC). ATX inhibited viability of OSCC cells but not NHOK. In OSCC cells, ATX further enhanced the cell death induced by IR. In addition, ATX promoted the MDA content, Iron levels but inhibited the GSH regulated by IR in cells. ATX could synergize with IR, further inhibiting GPX4, SLC7A11 and promoting ACSL4 in OSCC cells. In vivo, ATX and IR treatment inhibited OSCC tumor growth and the group with combined treatment showed the most inhibitory effect. GPX4 was inhibited by IR and further inhibited in the combined group while ACSL4 was promoted by IR and enhanced more significantly in the combined group. ATX might synergize with IR treatment in OSCC partly via ferroptosis.