A novel approach to rescue immune escape in oral squamous cell carcinoma: Combined use of interferon-γ and LY294002.

Major histocompatibility complex (MHC) class I molecules have been found to be downmodulated in many tumors. The antigen-processing machinery (APM) genes, especially transporters associated with antigen processing (TAP)-1 and tapasin play important roles in the processing of class I antigens. In this study, we investigated the expression of TAP-1 and tapasin in oral squamous cell carcinoma (OSCC); the result indicated significant down-regulation in the expression of these genes. Interferon (IFN)-γ treatment was applied. After the addition of IFN-γ, unexpectedly, the phosphoinositide 3-kinase (PI3K)/AKT signaling pathway was activated, which induced the proliferation of tumor cells. With the combined application of LY294002 (specific inhibitor of AKT signaling) and IFN-γ, tumor cell apoptosis was induced and the expression of TAP-1 and tapasin was still up-regulated. Hence, our method is a novel and efficient approach to use IFN-γ for rescuing the cells from immunosurveillance.