Reprogramming Virus-Primed Immunity for Targeted Immunotherapy of Ovarian Cancer

/ABSTRACT Epithelial ovarian cancer (EOC) remains the most lethal gynecologic malignancy. Development of immune therapies in EOC has been challenging, and clinical trials of immune checkpoint blockade (ICB) and bispecific T cell engagers (BiTEs) have been met with only limited success. The immunosuppressive TME and poor T cell priming in EOC result in lack/exclusion of T cell effectors necessary for ICB or BiTE efficacy. We have demonstrated that engineered oncolytic viruses such as Newcastle Disease Virus (NDV) expressing IL-12 can promote priming of tumor-specific T cell responses and result in a large number of activated tumor-infiltrating lymphocytes (TILs), however, we find that a large proportion of these TILs is dominated by anti-viral T cells. The central premise of our proposal aims to transform the dominant antiviral response from a liability into a therapeutic asset targeting both EOC cells and immunosuppressive TME. We hypothesize that T cell response generated by NDV infection represents an abundant and therapeutically tractable effector population that can be redirected with BiTEs to target cancer cells and other immunosuppressive cell populations in the TME, while capitalizing on the NDV potential to promote tumor-specific immunity. To test our hypothesis, we will take advantage of syngeneic mouse models of EOC and of organotypic slice cultures of human EOCs to evaluate the therapeutic and biologic impact of redirection of NDV-induced T cells against cancer cells, myeloid cells, and cancer-associated fibroblasts and will test it in the setting of distinct TME phenotypes and heterogeneous target antigen expression. In Aim 1, we will evaluate NDV-IL12 and cancer-directed (MUC16 and CLDN6) BiTE efficacy in vitro against murine and human EOC cell lines, ex vivo in human EOC slice cultures, and in vivo in murine orthotopic models of homologous recombination repair-deficient and -proficient EOC. In Aim 2, by employing BiTEs against TREM2, FOLR2, CD9, and FAP we will determine whether redirecting antiviral T cells toward myeloid or stromal targets improves anti-tumor effector T cell infiltration, activation, and cytotoxicity within the TME and will determine whether combinations with cancer cell-directed BiTEs further promote therapeutic efficacy. In Aim 3, we will take advantage of our innovative spatial genomics platform (Perturb-Map) that utilizes protein code (Pro-Code)-tagged cell libraries to enable simultaneous in vivo spatial resolution of multiple clonal EOC neighborhoods with distinct TME phenotypes. In these models of heterogeneous EOC TMEs we will test whether BiTE-redirected T cell killing of tumor, myeloid, or stromal cells is differentially impacted by distinct underlying TME phenotypes. Separately, MUC16-positive and -negative tumor cell lines will be used in mixedpopulation models and distinct tumor site models to test whether BiTE-redirected T cells initiate secondary endogenous T cell responses against untargeted tumor antigens locally and at distant sites. This proposal directly addresses key barriers to immunotherapy success in EOC and may define broadly applicable strategies for overcoming immune resistance in ovarian cancer and other tumors. Mouse model remains the best system for preclinical studies of tumor immunology and testing of immunotherapeutic approaches and will be utilized in this proposal along with other in vitro systems. Since the studies in the current proposal assess the development of immune responses and their impact on tumor growth and tumor microenvironment, computational and in vitro approaches are unfortunately inadequate for such studies. Project Number: 1R01CA317668-01 | Fiscal Year: 2026 | NIH Institute/Center: National Cancer Institute (NCI) | Principal Investigator: Dmitriy Zamarin | Institution: ICAHN SCHOOL OF MEDICINE AT MOUNT SINAI, NEW YORK, NY | Award Amount: $696,221 | Activity Code: R01 | Study Section: Translational Immuno-oncology Study Section[TIO] View on NIH RePORTER: https://reporter.nih.gov/project-details/11430004