THE FUNCTION OF CASPASE-8 IN CANCER, ANTI-CANCER IMMUNITY, AND CAR-T CELL FUNCTION

Project Summary/Abstract: Caspase-8 is the primary protein that drives the extrinsic apoptotic pathway, and is frequently mutated, contains polymorphisms, or downregulated in various cancers. Through the literature and many previous findings in our lab, we have identified potential apoptotic and non-apoptotic roles of caspase-8 in modulating T cell killing

and inflammatory signaling. Further, my preliminary data identifies differences in T cell effector markers/function as well as potential macrophage cytokine signaling. Taken together, these findings implicate Caspase-8 in interferon responses, macrophage cytokine production, and T cell effector function, all of which have known

importance in anti-cancer immunity. However, despite the downregulation of Caspase-8 in various cancers and its widespread inflammatory functions in apoptotic and non-apoptotic signaling pathways, its roles in promoting or inhibiting anticancer immunity or affecting immunotherapies have not been explored.

Thus, the two proposed project aims seek to interrogate the role of Caspase-8 in tumor cells as well as the tumor microenvironment, with a focus on its potential roles on anticancer immunity and CAR-T cell function. The goal of Aim 1 seeks to understand the roles of Caspase-8 in cancer cells which influence anti-cancer

immunity. Specifically, this aim will compare relevant murine cancer cells with or without Caspase-8 to identify differences in (1) proliferation and inflammatory signaling, (2) resistance to CAR-T cell induced killing (3) in vivo growth and immune cell infiltration. The goal of Aim 2 seeks to understand the roles of Caspase-8 in the tumor microenvironment (TME),

including immune cells and stromal cells, which influence anticancer immunity. Specifically, this aim will compare how caspase-8 in the TME alters (1) macrophage polarization, in vivo tumor growth, and immune infiltration, and (2) ability for CAR-T cells to induce death in relevant murine cancer cells.

The training plan focuses on extending my previous experience in cancer biology and current experience in the field of cell death into the field of immunology by exposing me to advanced techniques in the field of immuno-oncology. From presenting at departmental journal clubs, lab meetings, and seminars, to institutional

and international conferences, I will improve my presentation skills. Through a K99 application and manuscript preparation, I will continue to maintain my writing skills. Finally, through advanced coursework and shadowing, I will increase my knowledge and experience in the fields of immunotherapies and clinical trials.

The training environment at St. Jude boasts numerous cores which assist with mouse work and gene editing, while the Immunology department itself boasts flow cytometry and Immunologic Imaging cores specifically designated for the department. In addition to the many cores, St. Jude hosts numerous symposiums

and provides funding for postdoctoral fellows to receive additional training via courses and conferences.