Saturday, April 27, 2024
4/27/2024
PROJECT SUMMARY/ABSTRACT Chimeric antigen receptor (CAR) T cell therapy has revolutionized the treatment of pediatric patients with hematologic malignancies, yet robust responses to this modality in solid tumors have been lacking. As a result, most pediatric patients with relapsed or refractory solid tumors remain in dire need of alternative therapy. Given the inhospitable solid tumor microenvironment, we are unlikely to achieve robust responses without the most highly potent CAR T cells. My previous studies in vitro and in mice have demonstrated that CAR T cell potency can be enhanced by increasing the affinity of CAR for its cognate antigen. Further investigation revealed that in particular cytotoxicity was enhanced, whereas T cell survival and central memory (Tcm) differentiation (both important in CAR T clinical persistence and efficacy) were actually impaired in the high affinity CAR T cells. These findings raise questions regarding the cellular signaling events underlying these discordant effects and highlight the possibility that by reversing these decrements in survival and memory in the high affinity cells, CAR T cell potency could be unleashed even further. This mentored career development proposal will test the hypothesis that increased CAR affinity results in faster and more sustained activation of downstream T cell signaling pathways, enhancing cytotoxic granule release yet overly engaging signaling molecules such as ERK and Akt, tipping the cellular balance away from survival and memory differentiation and toward cell death. To test the hypothesis, I will use selected panels of affinity variants to evaluate the relationship between CAR affinity and the activation kinetics of key signaling pathways by quantitative Western blot. I will further evaluate the impact of CAR affinity on both cytotoxic granule release using microscopy as well as T cell survival and memory differentiation in vitro using flow cytometry. Lastly, I will identify and evaluate targetable mediators of the survival balance operating in high affinity CAR T cells in vitro and in tumor-bearing mice. To do so, I will compare the affinity variant CAR T cells’ survival and Tcm differentiation in the presence or absence of specific inhibitors of pathways (MEK, Akt, and Fas) that when over-activated can impair T cell survival or memory differentiation. These studies are expected to yield potent CAR T cells equipped to address the challenge of solid tumors where both efficient killing and robust persistence are necessary for efficacy. This work is to be completed under the co-mentorship of Drs. Michael Milone and Stephan Grupp and with the guidance of my Scientific Advisory Committee members Drs. Burkhardt, Kambayashi, and Dustin. The training plan developed for this proposal is designed to provide me with skills such as advanced microscopy techniques that are necessary to best address the proposed research questions. The scientific and training components of this proposal will help provide a strong foundation on which transition to an independent investigator.
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).
