Anti-prostate cancer effects of CTL cell induction in vitro by recombinant adenovirus mediated PSMA/4-1BBL dendritic cells: an immunotherapy study

This study aimed to examine anti-prostate cancer immune response induced by dendritic cells (DCs) transduced with PSMA/4-1BBL recombinant adenoviruses in vitro. Ad-PSMA, Ad-4-1BBL, and Ad-GFP were transfected into DCs derived from peripheral blood of healthy volunteers. Ad-PSMA/4-1BBL-DC, Ad-PSMA-DC, Ad-4-1BBL-DC, Ad-GFP-DC, and normal-DC, PSMA and 4-1BBL protein levels in DCs were detected by western blot. IL-12, IFN-γ and IL-10 were measured by ELISA. Mixed lymphocyte reaction and the cytotoxicity of each group targeted to LNCap, Du145, and 22RV prostate cancer cells were determined by CCK-8 assay. PSMA and 4-1BBL protein could express on DC successfully, the IL-12 supernatant content (134.29 ± 2.22 pg) was higher than others (P < 0.05). The ability to stimulate autologous T lymphocyte proliferation in the co-transfection group was higher than others (P < 0.05). When the DCs were co-cultured with CTLs, the PSMA/4-1BBL-DC-CTL group showed the highest content of IFN-γ (1176.10 ± 14.37pg/5 x 10(6) cells), but the lowest IL-10 content (75.14 ± 2.01 pg/5 x 10(6) cells) (P < 0.05), and the strongest anti-tumor effect when the effector to target ratio was 40:1, along with a higher killing ratio of LNCap cells than others (P < 0.05). Overall, Mature DCs transfected with Ad-PSMA/4- 1BBL not only showed high secretion of IL-12, but also induced CTLs to stimulate and enhance the killing effect of PSMA specific effector cells to PSMA positively expressing prostate cancer cells. Furthermore, the DCs infected with two kinds of tumor-associated antigens would induce more effective tumor-specific CTL induction.