Abstract 951: A novel oncolytic adenovirus platform with multi-gene immunomodulation for ovarian cancer treatment

Abstract Ovarian cancer (OC) remains a challenging malignancy with limited treatment options and a poor prognosis, emphasizing the urgent need for innovative therapeutic strategies. We have established a conditionally replicating oncolytic adenovirus (CRAd) platform designed to selectively target CA125 transactivation for OC treatment. To enhance therapeutic efficacy, we engineered the CRAd to include two gene-expression cassettes in the E3 region and each cassette can express two genes linked by a P2A peptide, enabling the incorporation of four exogenous genes in one virus. We rationally chose the following cytotoxic and immunoregulatory genes to integrate into one virus to enhance oncolytic and immunoregulatory capacity and amplify the anti-cancer immune response, full-length tumor necrosis factor-related apoptosis-inducing ligand (fl-TRAIL), CD137L, granulocyte-macrophage colony-stimulating factor (GM-CSF), and interferon alpha-2b (IFN-α2b). We successfully generate the virus by transfecting the recombined Ad/Muc16 genome into HEK293 packaging cells. Ovarian cancer cells expressing CA125 were infected with Ad/Muc16, and expression of all four genes were confirmed via ELISA or flow cytometry. The anti-cancer efficacy of Ad/Muc16 was evaluated in immune-competent syngeneic mouse models of ovarian cancer (ID8/C57BL/6 and STOSE/FVB mice). Mouse ovarian cancer cells (ID8 and STOSE) infected with Ad/Muc16 were served as a whole-cell cancer vaccine in a subcutaneous inoculation model to establish an immune response. The vaccinated mice were re-challenged with parental ovarian cancer cells. Ad/Muc16 treatment elicited a robust anti-cancer immune response, significantly suppressing the growth of re-challenged parental cells and prolonging survival compared to control groups. This CRAd platform integrate with multiple genes demonstrates a novel strategy for specific targeting OC by combining oncolytic virotherapy with immune modulation. Citation Format: Er Yue, Edward Wang. A novel oncolytic adenovirus platform with multi-gene immunomodulation for ovarian cancer treatment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 951.