Friday, May 9, 2025
5/9/2025
Sensitizing solid tumors to perforin-independent CAR T-cell killing - PROJECT SUMMARY/ABSTRACT Chimeric antigen receptor (CAR) T-cells are T-cells engineered with synthetic receptors that direct their specificity and function toward an antigen of choice. This application has been highly successful in treating a variety of blood-borne cancers, such as B-cell lymphoma where CAR T-cells are directed against CD19 on cancerous B-cells. CAR T-cells against solid tumors have been less efficacious, with one reason being the resistance of tumor cells to T cell-mediated cytotoxicity. Current paradigm suggests that tumor cells are killed by perforin/granzyme-secreting CD8 cytotoxic T cells (CTLs). However, activated CD4 and CD8 T cells also produce TNF and IFNγ, two cytokines that have been reported to have anti-tumor function, but it is not clear whether these cytokines can directly kill tumor targets. I now provide preliminary evidence that T cells can use a combination of TNF and IFNγ, in addition to perforin, to kill B16 melanoma cells. I propose to dissect the mechanism by which the two cytokines synergize to kill target cells. Furthermore, sensitivity to killing by the two cytokines can be enhanced by deleting molecules in the TNF pathway that suppress the death-signaling potential of the kinase RIPK1. Therefore, I hypothesized that this could be a strategy to sensitize solid tumors to killing by both CD8 and CD4 CAR T-cells producing TNF and IFNγ. I will conduct proof-of-concept studies to test this hypothesis. I further propose that the cell death triggered by TNF and IFNγ is inflammatory in nature. I will test if this leads to a downstream immunological response to cause epitope spreading and establishment of a memory response against other tumor-associated antigens, acting essentially as a ‘tumor vaccine.’ This fellowship will combine training in molecular pathways of cell death (provided by the Sponsor Dr. Ting) and in tumor immunology (provided by the Co-Sponsor Dr. Dong). Completion of these aims will provide me with experience in molecular, biochemical, cellular, and in vivo techniques, applied to the tumor immunology setting. Additionally, I will utilize high dimensional transcriptomic approaches to assess how death effects the tumor microenvironment and learn how to analyze this data by single cell analysis, providing me thorough training in applied bioinformatics. I will also be trained in oral and written scientific communications, including grant and manuscript writing. Through programs offered at my institution, I will also have the opportunity to participate in internships, and other training programs, in preparation for the next step in his scientific career.
HHS’ Tracking Accountability in Government Grants System (TAGGS) website provides access to detailed descriptions of grants, loans, aggregated direct payments and other types of financial assistance awarded by the HHS Operating Divisions (OPDIVs) and the Office of the Secretary Staff Divisions (STAFFDIVs).