Bioinformatics and immunohistochemistry analyses of expression levels and clinical significance of CXCL2 and TANs in an oral squamous cell carcinoma tumor microenvironment of Prophyromonas gingivalis infection

Bacteriome and mycobiome dysbiosis in oral mucosal dysplasia and oral cancer

It has long been considered that the oral microbiome is tightly connected to oral health and that dysbiotic changes can be detrimental to the occurrence and progression of dysplastic oral mucosal lesions or oral cancer. Improved understanding of the concepts of microbial dysbiosis together with advances in high-throughput molecular sequencing of these pathologies have charted in greater microbiological detail the nature of their clinical state. This review discusses the bacteriome and mycobiome associated with oral mucosal lesions, oral candidiasis, and oral squamous cell carcinoma, aiming to delineate the information available to date in pursuit of advancing diagnostic and prognostic utilities for oral medicine.

Inflammatory response-related genes predict prognosis in patients with HNSCC

BACKGROUND

Head and neck squamous cell carcinoma (HNSCC) is the most common malignancy of the head and neck, and the inflammatory microenvironment can impact the prognosis of HNSCC. However, the contribution of inflammation to tumour progression has not been fully elucidated.

METHODS

The mRNA expression profiles and corresponding clinical data of HNSCC patients were downloaded from The Cancer Genome Atlas (TCGA) database. The least absolute shrinkage and selection operator (LASSO) Cox analysis model was used to identify prognostic genes. The overall survival (OS) between high- and low-risk patients was compared by Kaplan‒Meier analysis. The independent predictors of OS were determined by univariate and multivariate Cox analyses. Single-sample gene set enrichment analysis (ssGSEA) was used to assess immune cell infiltration and immune-related pathway activity. GSEA was used to analyse Gene Ontology (GO) terms and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. The Gene Expression Profiling Interactive Analysis (GEPIA) database was used to examine prognostic genes in HNSCC patients. Immunohistochemistry was used to verify the protein expression of prognostic genes in HNSCC samples.

RESULTS

An inflammatory response-related gene signature was constructed by LASSO Cox regression analysis. HNSCC patients in the high-risk group showed significantly reduced OS compared with those in the low-risk group. The predictive capacity of the prognostic gene signature was confirmed by ROC curve analysis. Multivariate Cox analysis revealed that the risk score was an independent predictor for OS. Functional analysis indicated that the immune status was markedly different between the two risk groups. The risk score was significantly related to tumour stage and immune subtype. The expression levels of the prognostic genes were significantly related to the sensitivity of cancer cells to antitumour drugs. Furthermore, high expression of the prognostic genes significantly predicted poor prognosis of HNSCC patients.

CONCLUSIONS

The novel signature containing 9 inflammatory response-related genes reflects the immune status of HNSCC and can be used for prognosis prediction. Furthermore, the genes may be potential targets for HNSCC treatment.

PLAU and LAMC2 can predict a poor prognosis in patients with HNSCC

Objectives: Head and neck squamous cell carcinoma (HNSCC) is the most common malignancy of the head and neck. However, the molecular mechanisms governing the development of HNSCC have not been fully elucidated. Materials and Methods: Differentially expressed genes (DEGs) were screened out from The Cancer Genome Atlas (TCGA) and GSE23036 datasets. Weighted gene coexpression network analysis (WGCNA) was used to reveal the correlations among genes and to search for significantly correlated gene modules. The expression levels of genes in HNSCC and normal samples according to antibody-based detected methods was assessed by utilizing the Human Protein Atlas (HPA). The impact of the selected hub genes on the prognosis of HNSCC patients was assessed by analysing immunohistochemistry (IHC) and immunofluorescence (IF) expression levels and clinical data. Results: Twenty-four genes positively correlated with tumour status and 15 genes negatively correlated with tumour status were screened out by WGCNA. PLAU and LAMC2 were associated with a poor prognosis in patients with HNSCC and were finally screened out and verified by GEPIA and HPA database analysis. Immunohistochemistry of samples collected from 175 patients with HNSCC and subsequent statistical analysis also showed that PLAU and LAMC2 were associated with a poor prognosis in patients with HNSCC, and the levels of these two factors were positively correlated. The expression and co-localization of PLAU and LAMC2 in HNSCC tissues were confirmed by double immunofluorescence labeling. Conclusions: There was a positive correlation between PLAU and LAMC2 expression in HNSCC samples, and PLAU and LAMC2 might be independent prognostic biomarkers for HNSCC.

Porphyromonas gingivalis promotes the progression of oral squamous cell carcinoma by activating the neutrophil chemotaxis in the tumour microenvironment

BACKGROUND

We aimed to determine the significance of Porphyromonas gingivalis (P. gingivalis) in promoting tumour progression in the tumour microenvironment (TME) of oral squamous cell carcinoma (OSCC).

METHODS

The Gene Expression Omnibus (GEO) was used to screen out the differentially expressed genes from the two datasets of GEO138206 and GSE87539. Immunohistochemistry and immunofluorescence analysis of samples, cell biological behaviour experiments, and tumour-bearing animal experiments were used to verify the results in vivo and in vitro. The mechanism was revealed at the molecular level, and rescue experiments were carried out by using inhibitors and lentiviruses.

RESULTS

CXCL2 was selected by bioinformatics analysis and was found to be related to a poor prognosis in OSCC patients. Samples with P. gingivalis infection in the TME of OSCC had the strongest cell invasion and proliferation and the largest tumour volume in tumour-bearing animal experiments and exhibited JAK1/STAT3 signalling pathway activation and epithelial-mesenchymal transition (EMT). The expression of P. gingivalis, CXCL2 and TANs were independent risk factors for poor prognosis in OSCC patients. A CXCL2/CXCR2 signalling axis inhibitor significantly decreased the invasion and proliferation ability of cells and the tumour volume in mice. When lentivirus was used to block the CXCL2/CXCR2 signalling axis, the activity of the JAK1/STAT3 signalling pathway was decreased, and the phenotype of EMT was reversed.

CONCLUSION

Porphyromonas gingivalis promotes OSCC progression by recruiting TANs via activation of the CXCL2/CXCR2 axis in the TME of OSCC.

The interplay between oral microbes and immune responses

Oral microbes play a critical role in maintaining oral homeostasis. Microbial dysbiosis promotes disease pathogenesis through several mechanisms. Recent studies have revealed that microbial imbalance and sustained inflammation are involved in disease progression. The adverse interaction triggered by a host immune response to microorganisms can lead to oral and systemic diseases. Here, we reviewed how oral microbes communicate with hosts during the development of local and distant inflammation. Elucidation of these processes may reveal future directions in this field and the potential targets of novel biological therapies for oral and systemic diseases.

The ‘Danse Macabre’—Neutrophils the Interactive Partner Affecting Oral Cancer Outcomes

Over the past few decades, tremendous advances in the prevention, diagnosis, and treatment of cancer have taken place. However for head and neck cancers, including oral cancer, the overall survival rate is below 50% and they remain the seventh most common malignancy worldwide. These cancers are, commonly, aggressive, genetically complex, and difficult to treat and the delay, which often occurs between early recognition of symptoms and diagnosis, and the start of treatment of these cancers, is associated with poor prognosis. Cancer development and progression occurs in concert with alterations in the surrounding stroma, with the immune system being an essential element in this process. Despite neutrophils having major roles in the pathology of many diseases, they were thought to have little impact on cancer development and progression. Recent studies are now challenging this notion and placing neutrophils as central interactive players with other immune and tumor cells in affecting cancer pathology. This review focuses on how neutrophils and their sub-phenotypes, N1, N2, and myeloid-derived suppressor cells, both directly and indirectly affect the anti-tumor and pro-tumor immune responses. Emphasis is placed on what is currently known about the interaction of neutrophils with myeloid innate immune cells (such as dendritic cells and macrophages), innate lymphoid cells, natural killer cells, and fibroblasts to affect the tumor microenvironment and progression of oral cancer. A better understanding of this dialog will allow for improved therapeutics that concurrently target several components of the tumor microenvironment, increasing the possibility of constructive and positive outcomes for oral cancer patients. For this review, PubMed, Web of Science, and Google Scholar were searched for manuscripts using keywords and combinations thereof of “oral cancer, OSCC, neutrophils, TANs, MDSC, immune cells, head and neck cancer, and tumor microenvironment” with a focus on publications from 2018 to 2021.

Role of Porphyromonas gingivalis in oral and orodigestive squamous cell carcinoma

Oral and esophageal squamous cell carcinomas harbor a diverse microbiome that differs compositionally from precancerous and healthy tissues. Though causality is yet to be definitively established, emerging trends implicate periodontal pathogens such as Porphyromonas gingivalis as associated with the cancerous state. Moreover, infection with P. gingivalis correlates with a poor prognosis, and P. gingivalis is oncopathogenic in animal models. Mechanistically, properties of P. gingivalis that have been established in vitro and could promote tumor development include induction of a dysbiotic inflammatory microenvironment, inhibition of apoptosis, increased cell proliferation, enhanced angiogenesis, activation of epithelial-to-mesenchymal transition, and production of carcinogenic metabolites. The microbial community context is also relevant to oncopathogenicity, and consortia of P. gingivalis and Fusobacterium nucleatum are synergistically pathogenic in oral cancer models in vivo. In contrast, oral streptococci, such as Streptococcus gordonii, can antagonize protumorigenic epithelial cell phenotypes induced by P. gingivalis, indicating functionally specialized roles for bacteria in oncogenic communities. Consistent with the notion of the bacterial community constituting the etiologic unit, metatranscriptomic data indicate that functional, rather than compositional, properties of the tumor-associated communities have more relevance to cancer development. A consistent association of P. gingivalis with oral and orodigestive carcinoma could have diagnostic potential for early detection of these conditions that have a high incidence and low survival rates.

Protein tyrosine kinase 7-knockdown inhibits oral squamous cell carcinoma cell viability, proliferation, migration and invasion via downregulating dishevelled segment polarity protein 3 expression

Protein tyrosine kinase 7 (PTK7) expression has been reported to be dysregulated and to regulate various cellular activities in numerous types of cancer. However, to the best of our knowledge, the status and role of PTK7 in oral squamous cell carcinoma (OSCC) remains largely unknown. The present study aimed to investigate the involvement of PTK7 in OSCC progression and to determine the potential underlying mechanisms of action. The expression levels of PTK7 and dishevelled segment polarity protein 3 (DVL3) in OSCC cell lines were analyzed using reverse transcription-quantitative PCR and western blotting. A co-immunoprecipitation assay was used to verify the binding association between PTK7 and DVL3. In addition, OSCC cells were transfected with a short hairpin RNA targeting PTK7 or pcDNA-DVL3 overexpression vectors. The effect of PTK7 on OSCC cell viability, proliferation, migration and invasion, and the underlying mechanisms, were investigated using Cell Counting Kit-8, colony formation, wound healing and Transwell assays, respectively. Western blotting was used to analyze the expression levels of proliferation- and migration-associated proteins. The results revealed that the expression levels of both PTK7 and DVL3 were significantly upregulated in OSCC cell lines. In addition, a binding association was identified between PTK7 and DVL3 in SCC-9 cells. The knockdown of PTK7 expression inhibited OSCC cell viability, proliferation, invasion and migration, while the overexpression of DVL3 reversed the inhibitory effects of PTK7-knockdown on OSCC cells. In conclusion, the results of the present study suggested that PTK7 may be a key regulator of OSCC proliferation, migration and invasion, and PTK7-knockdown may inhibit OSCC cell viability, proliferation, invasion and migration by downregulating DVL3 expression. Therefore, PTK7 and DVL3 may represent potential biomarkers for diagnosis and treatment, as well as promising drug targets for OSCC.