Over-expressing transporters associated with antigen processing increases antitumor immunity response in prostate cancer

As we know, prostate cancer down-regulates expression of HLA-1 Antigen Processing Machinery (APM) and has defects in the antigen presentation pathway. In vitro, the prostate cancer cell (PC-3 cells) infected with Lentivirus TAP1 can efficiently over-express TAP1 and Tapasin, and HLA-1 was also up-regulated on the surface of the infected cells. The lentivirus TAP1 infection increased the apoptosis rate of PC-3 cells. In addition, with the co-cluture PC-3 cells and lymphocytes, TAP1 augmented the expression of CD3+CD8+CD38+ T cell. Importantly, administration of Lentivirus TAP1 to prostate cancer cells in a xenograft mouse model can prolong survival and increase the CD4+ T cells, and CD8+ T cells as well as decrease Foxp3+ T cells in the tumor microenvironment. In summary, a recombinant lentivirus expressing TAP1 can effectively increase prostate cancer tumor-specific immune response.