The five year survival rate for ovarian cancer (OC) patients has remained at 47% for over two decades. OC is characterized by a highly suppressive tumor microenvironment and current research efforts focus on reversing this immune suppression. One way to activate the immune response against OC is using epigenetic therapeutics, which stimulate an interferon response in cancer cells by inducing the transcription of repetitive elements (REs)—genomic regions that resemble the genetic material of some viruses. As REs are normally silent in terminally differentiated cells, their upregulation in tumor cells suggests that these genomic elements can be used as inducible treatment targets. T cells specific for an RE-derived antigen, the non-functional envelope gene of endogenous retrovirus K (ERV-K-Env), can recognize their cognate antigen and kill OC cells while sparing healthy cells. Whether these T cells will be more lytic when combined with immunogenic epigenetic therapy is unknown. Aside from ERV-K-Env, other epigenetically upregulated REs serve as an unexplored pool of tumor-associated antigens that may be novel treatment targets. I hypothesize that combining epigenetic therapy with RE-specific T cells will have potent immunogenic and targeted anti-tumor efficacy in OC. In Aim 1, I will determine the effect of combination epigenetic therapy and ERK-K-Env-specific T cells in OC. Preliminary data suggest this candidate RE, ERV-K-Env, is a targetable tumor-associated antigen in OC. I hypothesize that combining epigenetic therapy with ex vivo expanded ERV-K-Env-specific T cells will result in targeted immunogenic OC cell killing. ERV-K-Env-specific T cells will be expanded ex vivo from whole blood donors and assessed in vitro for antigen specificity. I will co-culture the expanded T cells with epigenetically treated OC cells and assess T cell activation and cytotoxicity in vitro and in vivo. In Aim 2, I will identify and target additional tumor-associated RE peptides as novel OC tumor antigens. Preliminary data from my lab suggest that epigenetic treatment results in the upregulation of REs and their presentation on the surface of OC cells to the immune system. I hypothesize that diverse tumor-associated REs upregulated by epigenetic therapy can be therapeutically relevant T cell targets in OC. Bioinformatic tools will be used to identify which REs upregulated by epigenetic therapy have the potential to be T cell antigens. I will validate the immunogenicity of these antigens by expanding RE-specific T cells from healthy donors and assess the clinical relevance of the experimentally validated REs as treatment targets using OC patient T cells. Completion of the proposed project will provide new knowledge on the combination of epigenetic therapy with RE-specific T cells as a novel immunogenic and potentially curative treatment strategy for OC. Collectively, these innovative interdisciplinary experiments will shed light on the understudied role of REs as t...