Exosomal microRNAs Targeting TP53 Gene as Promising Prognostic Markers for Head and Neck Squamous Cell Carcinoma

Differential gene expression profile in Porphyromonas gingivalis treated human gingival keratinocytes and their role in the development of HNSCC

Background

Periodontitis is considered to be one of the major risk factors associated with cancers of the oral cavity. Periodontogenic pathogens such as Porphyromonas gingivalis, Treponema denticola, Tannerella forsythia, Fusobacterium nucleatum and Aggregatibacter actinomycetemcomitans are the important pathogens associated with periodontitis. Chronic exposure to bacterial components induces changes in the nearby cells. Hence, the present study has been designed to identify the molecular mechanisms that could be associated with the two disease conditions viz., periodontitis and head and neck cancer.

Objective

The present study investigated the differential gene expression profile in human gingival keratinocytes treated with P. gingivalis (Pg), a bacterium associated with periodontal disease, and its possible association with the development of Head and Neck Squamous Cell Carcinoma (HNSCC).

Methods

The study followed a computational design. Multiple tools and databases, such as GEOmnibus, STRING, Metascape, PANTHER, and UALCAN, cBioportal, were used to derive an association between gene expression during infection with P. gingivalis, and the resulting gene expression profiles were analyzed in the HNSCC dataset.

Results

The study revealed 29 genes from a pool of transcripts acquired after comparing the Pg-HIGK and Sham-HIGK. Among them, 3 genes i.e., FST, VRK3, and SGK1, were found to be overexpressed and significantly influenced patient survival. The upregulation of FST was found to correlate with poor prognosis in HNSCC patients.

Conclusion

The study provided insights into the possible association of FST, VRK3 and SGK1 in the development of HNSCC. Further investigations are warranted to confirm the functional role of these genes in establishing the cancer phenotype in patients with chronic infection with Pg.

Exosomal microRNA let-7c-5p enhances cell malignant characteristics by inhibiting TAGLN in oral cancer

Background

Oral cancer, a malignancy that is prevalent worldwide, is often diagnosed at an advanced stage. MicroRNAs (miRNAs) in circulating exosomes have emerged as promising cancer biomarkers. The role of miRNA let-7c-5p in oral cancer remains underexplored, and its potential involvement in tumorigenesis warrants comprehensive investigation.

Methods

Serum samples from 30 patients with oral cancer and 20 healthy controls were used to isolate exosomes and quantify their RNA content. Isolation of the exosomes was confirmed through transmission electron microscopy. Quantitative PCR was used to assess the miRNA profiles. The effects of let-7c-5p and TAGLN overexpression on oral cancer cell viability, migration, and invasion were analyzed via CCK-8 and Transwell assays. Moreover, we conducted mRNA sequencing of exosomal RNA from exosomes overexpressing let-7c-5p to delineate the gene expression profile and identify potential let-7c-5p target genes.

Results

let-7c-5p was upregulated in serum-derived exosomes of patients with oral cancer. Overexpression of let-7c-5p in the TCA8113 and CAL-27 cell lines enhanced their proliferative, migratory, and invasive capacities, and overexpression of let-7c-5p cell-derived exosomes promoted oral cancer cell invasiveness. Exosomal mRNA sequencing revealed 2,551 differentially expressed genes between control cell-derived exosomes and overexpressed let-7c-5p cell-derived exosomes. We further identified TAGLN as a direct target of let-7c-5p, which has been implicated in modulating the oncogenic potential of oral cancer cells. Overexpression of TAGLN reverses the promoting role of let-7c-5p on oral cancer cells.

Conclusion

Our findings highlight the role of exosomal let-7c-5p in enhancing oral cancer cell aggressiveness by downregulating TAGLN expression, highlighting its potential as a diagnostic and therapeutic strategy.

Analysis of differentially expressed genes in dysplastic oral keratinocyte cell line and their role in the development of HNSCC

Dysplasia is the presence of abnormal types of cells in a tissue precipitated by over or diminished expression of certain genes. These cells act as a precursor to cancer. Dysplastic oral keratinocyte (DOK) cell lines have an aneuploid complex karyotype. They provide an opportunity to study the action of specific carcinogens on malignant transformations. This study aimed to identify the differentially expressed genes in dysplastic cells and their possible association with head and neck squamous cell carcinoma (HNSCC). These genes can be developed as diagnostic, prognostic, or therapeutic leads.The list of genes related to oral keratinocyte dysplasia and head and neck cancer was accessed from the GEO (Gene Expression Omnibus) database. Gene expression profiling was done between dysplastic oral keratinocytes and normal human oral keratinocytes. Gene expression and Kaplan Meier survival analysis were performed using the UALCAN database to assess the correlations between dysregulated genes identified in dysplastic keratinocytes and primary tumors of HNSCC. The GEO omnibus dataset identified numerous differentially expressed genes of which the top 10 up and downregulated genes in dysplastic oral keratinocytes were curated for further analysis. The expression profile of these genes was assessed using the HNSCC dataset (TCGA, Firehose Legacy). Among all the genes assessed, only one gene, the OLR1 gene encoding oxidized low-density lipoprotein, was found to be overexpressed in both the groups viz., dysplastic keratinocytes and HNSCC cases with a strong correlation with the survival status of patients. There was significant correlation between the gene expression pattern observed in dysplastic keratinocytes and the primary tumor of the HNSCC group, with an exotic gene that was seldom discussed in association with cancer, viz., OLR1. Exploration into other top-ranking differentially expressed genes in dysplastic cases would aid in identifying the candidate gene associated with both phenotypes.

Head and neck cancer: pathogenesis and targeted therapy

Head and neck cancer (HNC) is a highly aggressive type of tumor characterized by delayed diagnosis, recurrence, metastasis, relapse, and drug resistance. The occurrence of HNC were associated with smoking, alcohol abuse (or both), human papillomavirus infection, and complex genetic and epigenetic predisposition. Currently, surgery and radiotherapy are the standard treatments for most patients with early-stage HNC. For recurrent or metastatic (R/M) HNC, the first-line treatment is platinum-based chemotherapy combined with the antiepidermal growth factor receptor drug cetuximab, when resurgery and radiation therapy are not an option. However, curing HNC remains challenging, especially in cases with metastasis. In this review, we summarize the pathogenesis of HNC, including genetic and epigenetic changes, abnormal signaling pathways, and immune regulation mechanisms, along with all potential therapeutic strategies such as molecular targeted therapy, immunotherapy, gene therapy, epigenetic modifications, and combination therapies. Recent preclinical and clinical studies that may offer therapeutic strategies for future research on HNC are also discussed. Additionally, new targets and treatment methods, including antibody-drug conjugates, photodynamic therapy, radionuclide therapy, and mRNA vaccines, have shown promising results in clinical trials, offering new prospects for the treatment of HNC.

Understanding exosomes: Part 3-therapeutic + diagnostic potential in dentistry

Exosomes are the smallest subset of extracellular signaling vesicles secreted by most cells with the ability to communicate with other tissues and cell types over long distances. Their use in regenerative medicine has gained tremendous momentum recently due to their ability to be utilized as therapeutic options for a wide array of various diseases. Over 5000 publications are currently being published on this topic yearly, many of which in the dental space. This extensive review article is the first scoping review aimed at summarizing all therapeutic uses of exosomes in regenerative dentistry. A total of 944 articles were identified as using exosomes in the dental field for either their regenerative/therapeutic potential or for diagnostic purposes derived from the oral cavity. In total, 113 research articles were selected for their regenerative potential (102 in vitro, 60 in vivo, 50 studies included both). Therapeutic exosomes were most commonly derived from dental pulps, periodontal ligament cells, gingival fibroblasts, stem cells from exfoliated deciduous teeth, and the apical papilla which have all been shown to facilitate the regenerative potential of a number of tissues including bone, cementum, the periodontal ligament, nerves, aid in orthodontic tooth movement, and relieve temporomandibular joint disorders, among others. Results demonstrate that the use of exosomes led to positive outcomes in 100% of studies. In the bone field, exosomes were found to perform equally as well or better than rhBMP2 while significantly reducing inflammation. Periodontitis animal models were treated with simple gingival injections of exosomes and benefits were even observed when the exosomes were administered intravenously. Exosomes are much more stable than growth factors and were shown to be far more resistant against degradation by periodontal pathogens found routinely in a periodontitis environment. Comparative studies in the field of periodontal regeneration found better outcomes for exosomes even when compared to their native parent stem cells. In total 47 diagnostic studies revealed a role for salivary/crevicular fluid exosomes for the diagnosis of birth defects, cardiovascular disease, diabetes, gingival recession detection, gingivitis, irritable bowel syndrome, neurodegenerative disease, oral lichen planus, oral squamous cell carcinoma, oropharyngeal cancer detection, orthodontic root resorption, pancreatic cancer, periodontitis, peri-implantitis, Sjögren syndrome, and various systemic diseases. Hence, we characterize the exosomes as possessing "remarkable" potential, serving as a valuable tool for clinicians with significant advantages.

MicroRNAs targeting CDKN2A gene as a potential prognostic marker in head and neck squamous cell carcinoma

Epigenetic factors are known to markedly influence the functions of a gene by modification of transcripts, via methylation or acetylation and degradation of mRNA transcripts. The CDKN2A encodes cyclin-dependent kinase inhibitor 2A, a tumour suppressor protein. Genetic and epigenetic alterations in this gene have been demonstrated in several cancer types. The non-coding RNAs with a special emphasis on microRNAs have long been explored for their potential role in the epigenetic modification of gene expression. The present study aims to identify the microRNAs targeting CDKN2A gene transcripts and demonstrate their prognostic significance in head and neck squamous cell carcinoma (HNSCC). Computational approaches were employed to identify the microRNAs targeting CDKN2A. The gene and protein expression profile of CDKN2A was analyzed using UALCAN. A significant upregulation of CDKN2A was observed in the primary tumour tissues (p=<10-12). Interestingly, the protein expression, although found to be statistically significant (p=0.0129) did not correlate well with the gene expression profile. The microRNAs targeting CDKN2A were further analyzed to identify the possible reason for the decrease in protein expression. Among the 44 microRNAs targeting CDKN2A gene transcripts, hsa-miR-3681-3p, hsa-miR-542-5p, hsa-miR-4519 were found to be upregulated and hsa-miR-134-5p was found to be downregulated with a significant association with survival status of HNSCC patients. The hsa-miR-542-5p was found to correlate well with the survival and hence can be considered as the key microRNA associated with HNSCC. However, further validation of this microRNA is warranted to confirm its role in the process of carcinogenesis.

Pharmacological impact of microRNAs in head and neck squamous cell carcinoma: Prevailing insights on molecular pathways, diagnosis, and nanomedicine treatment

Head and neck squamous cell carcinoma is a disease that most commonly produce tumours from the lining of the epithelial cells of the lips, larynx, nasopharynx, mouth, or oro-pharynx. It is one of the most deadly forms of cancer. About one to two percent of all neo-plasm-related deaths are attributed to head and neck squamous cell carcinoma, which is responsible for about six percent of all cancers. MicroRNAs play a critical role in cell proliferation, differentiation, tumorigenesis, stress response, triggering apoptosis, and other physiological process. MicroRNAs regulate gene expression and provide new diagnostic, prognostic, and therapeutic options for head and neck squamous cell carcinoma. In this work, the role of molecular signaling pathways related to head and neck squamous cell carcinoma is emphasized. We also provide an overview of MicroRNA downregulation and overexpression and its role as a diagnostic and prognostic marker in head and neck squamous cell carcinoma. In recent years, MicroRNA nano-based therapies for head and neck squamous cell carcinoma have been explored. In addition, nanotechnology-based alternatives have been discussed as a promising strategy in exploring therapeutic paradigms aimed at improving the efficacy of conventional cytotoxic chemotherapeutic agents against head and neck squamous cell carcinoma and attenuating their cytotoxicity. This article also provides information on ongoing and recently completed clinical trials for therapies based on nanotechnology.