Abstract 1915: Novel synthetic DNA vaccines in prostate cancer immunotherapy

Abstract

Abstract Prostate cancer (PCa) represents the most predominant cancer type among males with an estimated 191,930 cases diagnosed in 2020 with 33,330 deaths globally. Notably, different treatment modalities such as surgery, chemo, radiation and hormone therapy exhibited improved outcomes in early stage PCa patients; however, there exist high recurrence rate in the treated patients and leads to castration resistant prostate cancer, the treatment choices for which are highly restricted. This scenario has pressed us to consider synthetic DNA vaccine-based immunotherapy approach, with ability to induce antigen-specific tumor-killing immune cells. Considering the high heterogeneity of prostate cancer cells, we hypothesized that synthetic DNA vaccines targeting multiple prostate specific antigens would elicit improved immune responses in those who are at high risk as well as advanced stages of prostate cancer. Therefore, we generated synthetic enhanced DNA immunogens as DNA constructs (SEV) targeting STEAP1, PAP, PARM1, PSCA, PCTA and PSP94 through utilization of bioinformatics approaches. The SEVs for prostate cancer antigens elicited potent cellular immunity as well as polyfunctionality of antigen-specific T cells in mice. Further, they were capable of generating robust humoral immune responses to each antigen. The anti-tumor activities of the SEVs were studied in prostate tumor which showed that the induced immune responses delayed tumor progression and enhanced infiltration of anti-tumor CD8+ T cells in the tumor microenvironment in a mouse model challenge system. These data highlight further study of these novel immunogens as synthetic DNA immunogens for immunotherapy of PCa, and perhaps other human cancers. Citation Format: Devivasha Bordoloi, Peng Xiao, Hyeree Choi, Michelle Ho, Alfredo Perales-Puchalt, Makan Khoshnejad, J.Joseph Kim, Laurent Humeau, Alagarsamy Srinivasan, David B. Weiner, Kar Muthumani. Novel synthetic DNA vaccines in prostate cancer immunotherapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1915.