Immunolocalization of Akt Isoforms in Oral Squamous Cell Carcinoma

Aberration of signal transducers in PI3K/AKT pathway has been found in many human cancers, and may play a critical role in carcinogenesis. Advanced research on oral cancer treatments, using novel agents targeting on the PI3K/AKT signaling pathway, are being investigated with promising results. Our previous study has shown overexpression and activation of Akt2 in oral cancer cell lines. Objective: The objective of the present study was therefore to investigate the immunolocalization of Akt1 and Akt2 in oral squamous cell carcinoma (OSCC) specimens. Methods: The protein expression of Akt1 and Akt2 in OSCC tissues was studied by immunohistochemical technique (n=20). Semiquantitative analysis of the expression of Akt1 and Akt2 was also performed. Results: The results revealed that Akt1 and Akt2 were expressed in all OSCC cases. Both Akt1 and Akt2 were localized mainly in the cytoplasm of OSCC cells, while the nuclei of OSCC cells and the overlying oral epithelial cells were negatively stained. Generally, Akt2 was expressed more intensely than Akt1 in OSCC cells. Approximately 90% of all OSCC cases exhibited greater than 50% of positively stained OSCC cells against both Akt1 and Akt2. Conclusion: The findings of the present study indicate that Akt1 and Akt2 are overexpressed in OSCC and may be involved in OSCC carcinogenesis. This study was supported by the National Research Council of Thailand to A.I., the Thailand Research Fund (RMU5080035), and the Center of Excellence for Innovation in Chemistry, Commission on Higher Education, Ministry of Education, Thailand, to S.K.