Viral priming and targeting NK cells against solid tumor malignancies

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DESCRIPTION (provided by applicant): During the last 2 decades I have had continuous NCI-funding in the areas of natural killer (NK) cell biology, development of immunotherapies and hematopoietic cell transplantation (HCT) for hematologic malignancies and acute myeloid leukemia (AML). My team, who pioneered adoptive transfer of NK cells, has the largest world experience having infused >200 haploidentical NK cell products to treat patients with hematologic and solid tumor malignancies. Recently we described a new paradigm in human NK cell biology by identifying a unique functional phenotype in NK cells induced by cytomegalovirus (CMV). These long-lived, highly differentiated NKG2C+/CD27+ cells, which we call "adaptive" NK cells are educated and enriched for the expression of self-inhibitory killer-cell immunoglobulin-like receptors (KIR). They represent the human equivalent of the memory-like Ly49H+ NK cells described in CMV-infected mice. Further, we identified expanded NK cell subsets selectively lacking the proximal signaling molecules FcϵR1γ, EAT-2 and SYK individually or in combination. Importantly, they are epigenetically primed for enhanced cytokine production and survival, and mediate potent antibody-dependent cellular cytotoxicity (ADCC) through CD16. The overarching goal of this Outstanding Investigator Award is to develop strategies to enhance the anti-tumor activity of endogenous NK cells in patients with solid tumor malignancies. The objective is to develop "off the shelf" reagents to activate NK cells, overcome inhibitory receptor signaling, and target them to specific tumor antigens. My group has developed several novel NK cell targeting agents, including bi-specific killer engagers (BiKEs), created by fusing scFv anti-CD16 with scFv for tumor antigens and IL-15/IL-15Rα-Fc complexes targeted to tumor antigens developed with an industry partner. In this proposal, we will evaluate the therapeutic potential for these agents using several strategies. First, epidemiologic genetic studies in patients with solid tumors will define the relationship between CMV and human papillomavirus (HPV) exposure, the development of virally-induced "adaptive" NK cells and the risk of cancer development and response to standard therapies. Second, we will evaluate a novel solid tumor antigen, RHAMM, expressed both on tumors and in the "cancerized" microenvironment. Third, we will use a novel xenogeneic model we will test the anti-tumor efficacy of "adaptive" NK cells targeted to RHAMM with our unique agents. Fourth, after preclinical evaluations, we will conduct phase I clinical trials of the optimal agents to treat sold tumor malignancies and will test the role of viral vaccines in inducing or enhancing "adaptive" NK cell function. Lastly, I will build on my long track record of mentorship to use these investigations as a platform to train future translational scientists. The innovative studies proposed here are well supported by preliminary data and represent an emerging area of considerable excitement in NK cell biology. The successful development of therapies to harness innate "adaptive" NK cells to target solid tumors will have a substantial impact the field of cancer immunotherapy.