Abstract 698: Developing a self-targeted cancer immunotherapy using engineered whole tumor cell-based vaccine

Abstract The administration of inactivated tumor cell lysate is known to induce a potent antitumor immune response, however, their therapeutic efficacy as shown in Phase I-III clinical trials is limited. This could be attributed to the lack of direct cytotoxic effect on tumor cells and the inability to trigger a strong antitumor immune response. Unlike inactivated tumor cells, living tumor cells possess a unique potential to home to and self-target tumors. Therefore, repurposing the tumor cells’ self-homing property and natural source of neoantigens is advantageous for self-targeted cancer immunotherapy. In this study, we developed a genetically engineered living whole cancer cell-based therapeutic with direct tumor killing and immunostimulatory roles. We switched the tumor cells from death ligands sensitive to resistant using CRISPR/Cas9 and subsequently engineered them to release dual cell killing and immunomodulatory agents. These engineered therapeutic tumor cells (ThTC) eliminated established tumor and activating antitumor immune cell trafficking and antigen-specific T cell activation signaling. This mechanism-based efficacy of ThTC translated into a marked survival benefit and long-term immunity in primary, recurrent, and metastatic cancer models in immunocompromised, immunocompetent and humanized mice. Arming naturally neoantigen-rich tumor cells with multidisciplinary therapeutics represents promising cell-based immunotherapy for solid tumors and establishes a roadmap towards clinical translation. Citation Format: Kok-Siong Chen, Natalia Claire Mendonca, Paulo Borges, Khalid Shah. Developing a self-targeted cancer immunotherapy using engineered whole tumor cell-based vaccine [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 698.