Abstract Text: In cancer immunotherapy, there is a need for clinically relevant therapies that tackle solid cancers and minimize systemic toxicity experienced by patients. We utilize genetic circuits that force tumors to release therapeutics that promote localized immune responses, without harming healthy tissues. This project’s aim was to promote tumor-specific allorejection in mouse strains. We developed a genetic circuit that selectively “hijacked” tumors of the C57BL/6 mouse strain, forcing them to express immunologically foreign alloantigens derived from a different strain, BALB/c. Consequently, C57BL/6 tumors would become “foreign” to the body, inducing tumor elimination via CD8 T-cell mediated allorejection. This circuit comprises 3 modules: Modules 1 and 2 (TF-sensor modules) harness tumor-specific activity of transcription factors and promoters; driven by TF-sensor modules, Module 3 (output module) enables tumors to express spleen-derived BALB/c alloantigens. Sensors of 20x and 6x tumor specificities were selected, following flow cytometry with ovarian cancer and melanoma cell lines. For complete circuit assembly, tumor cells (BPPNM, YUMM1.7) were lentivirally infected with all 3 modules and injected into C57BL/6 mice for in vivo validation. BPPNM mice treated with alloantigen-genetic circuits had 51.1% less tumor burden than the non-therapeutic negative controls’ tumors 5 days post-tumor inoculation. YUMM1.7 alloantigen-treated mice had mean tumor burdens ~4x lower than negative control mice 6 days post-tumor inoculation. Alloantigen-treated tumors grew slowly, persisting 19 days post-tumor inoculation. Negative control tumors grew aggressively, prompting euthanization 10 days post-tumor inoculation. These in vivo findings suggest preliminary anti-tumor efficacy of alloantigen-genetic circuits via T-cell responses and lower systemic toxicity.
