Analysis of the secretome from patients with oral squamous cell carcinoma revealed the presence of the periodontal pathogen Fusobacterium nucleatum and changes in the epithelial mesenchymal transition as a potential mechanism of cancer progression.

Objectives: The aim of this project was to identify pro tumoral periodontal bacteria and the potential mechanisms associated with tumor progression.
Methods: Biopsies from patients with OSCC and healthy controls were obtained and cultured in media for 48hrs to collect the secretome. Then, secretome samples from OSCC and control were characterized by proteomics using TIM TOF pro and analyzed with PEAKS Studio and Scaffold.
Results: The analysis revealed the presence of several proteins from Fusobacterium nucleatum in the secretome of OSCC patients. Then, the expression of epithelial mesenchymal transition (EMT)-associated proteins was analyzed and epithelial markers, such as cytokeratin (KRT)13, collagen a1, E-cadherin and T-cadherin were reduced in OSCC samples. On the other hand, a higher expression of mesenchymal markers such as metalloproteinase (MMP)9, MMP11, MMP14, integrins (ITG)-a6, ITG-b1, ITG-b4 and fibronectin were increased in the secretome of OSCC patients in comparison with control samples.
Conclusions: Our data revelated that the secretome of OSCC patients is associated with the presence of Fusobacterium nucleatum and the acquisition of EMT.