Salivary chemical barrier proteins in oral squamous cell carcinoma – alterations in the defense mechanism of the oral cavity

Introduction: Oral squamous cell carcinoma (OSCC) is one of the most frequent types of head and neck cancer and among the European countries; Hungary has the highest rate of incidence and mortality of OSCC. Despite the genetic and environmental risk factors, OSCC is also associated with microbial infections and/or dysbiosis. Saliva serves as the chemical barrier of the oral cavity since the most abundant salivary proteins belong to antimicrobial and immunomodulatory protein (AMP) family.

Aims: Considering that saliva contains many chemical barrier proteins and the fact that OSCC can alter the protein composition secreted into saliva, our aim was to analyze the effect of OSCC on the salivary chemical barrier proteins.

Materials and methods: Publicly available proteomics datasets regarding the analysis of salivary proteins from patients with OSCC and controls were collected and examined in order to identify differentially expressed chemical barrier proteins. Network analysis and gene ontology (GO) classification of the differentially expressed chemical barrier proteins were performed as well.

Results: One hundred and twenty-seven proteins showing different expression pattern between the OSCC and control groups were found. Protein-protein interaction networks of up- and down-regulated proteins were constructed and analyzed. The main hub proteins (IL-6, IL-1B, IL-8, TNF, APOA1, APOA2, APOB, APOC3, APOE, and HP) were identified and the enriched GO terms were examined. Our study highlights the importance of the chemical barrier of saliva in the development of OSCC.

This research was funded by NKFIH K143021 and GINOP-2.3.3-15-2016-00020.