Abstract 268: DNA-launched HPV E7 nanoparticle vaccine induces potent anti-tumor cytolytic T-cell responses

Abstract

Abstract Nanotechnology-based approaches have provided promising tools for development of novel cancer immunotherapeutic immunogens through the decoration of multiple antigens on nanoparticle scaffolds. However, challenges with inducing robust cytolytic T cell responses critical to anti-tumor immunity, as well as purification and scalability, have hampered their clinical translation. To address these challenges, here we present the design and characterization of a DNA-launched nanoparticle vaccine displaying the HPV E7 epitope for inducing anti-tumor immune responses. We designed a nanovaccine construct by scaffolding the HPV E7 epitope with bacterial enzyme lumazine synthase. We demonstrate that through electroporation-facilitated DNA vaccination encoding the antigen-scaffold construct, this nanovaccine self-assembles in vivo into nanoparticles displaying 60 copies of the antigen on its surface. Compared to vaccination with CpG-adjuvanted HPV E7 peptide, the DNA-launched nanovaccine induced significantly greater antigen-specific CD8+ T cell responses upon stimulation with the HPV E7 peptide as well as with the epitope natively expressed on the target tumor cells. In a flank model of TC-1 lung cancer, the DNA-launched nanovaccine achieved complete tumor protection in 70% of mice when administered prophylactically. With therapeutic treatment, the nanovaccine achieved complete tumor regression in 60% of mice. In addition, anti-tumor immunity was retained upon rechallenge over 100 days after initial tumor challenge, supporting the induction of immune memory. These promising results, along with its facile characterization and scalability, support that DNA-launched nanovaccines that self-assemble in vivo can induce significant anti-tumor cellular immunity and are ideally positioned for study in clinical translation. Citation Format: Kevin Liaw, Ziyang Xu, Nicholas Tursi, Neethu Chokkalingam, Daniel Kulp, David Weiner. DNA-launched HPV E7 nanoparticle vaccine induces potent anti-tumor cytolytic T-cell responses [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 268.