Methods: Based on our in vitro cellular carcinogenesis model of oral squamous cell carcinoma (OSCC), comparative proteomic analysis was performed using two-dimensional gel electrophoresis and liquid chromatography-tandem mass chromatography to separate and identify differentially expressed proteins.
Results: Fifty-four protein spots were separated, and 45 proteins were identified. Decreased expression of 24 proteins was found during cancerization from immortalized oral epithelial cells to squamous cancerous cells, and increased expression of 19 proteins was found during the cancerization. According to the Gene Ontology Convention, the identified known proteins were classified to three ontologies of cellular component, molecular function, and biological process. Further validation of five identified proteins (ANXA1, ANXA2, CTSB, KRT17, and S100A6) in the cellular carcinogenesis model and cancerous tissues from OSCC patients confirmed the comparative proteomic results. Moreover, Annexin A1 and A2 expressions were found correlating with the pathological differentiation grade of cancerous tissues.
Conclusion: This work provides a dynamic protein file of differentially expressed proteins to perform further investigations on mechanism researches of OSCC cancerization, as well as potential biomarkers for clinical diagnosis or prognostic monitoring.