N/A, N/AMontes, Raul Caballero2022-09-222022-09-222022-04-14https://hdl.handle.net/10657/11745Adoptive cell therapy using chimeric antigen receptor (CAR)-T cells represents a promising approach for human cancer immunotherapy. In this study, we examine the role of a MAP3K in mediating CAR-T cell function by generating CAR-T cells expressing a stable form of MAP3K lacking its N-terminal region (MAP3KK Delta N). We hypothesize that MAP3K Delta N expression will promote CAR-T cell activation and metabolic fitness in the tumor microenvironment. Using molecular cloning, a retroviral vector encoding a human CD19(hCD19)-specific CAR and mouse MAP3KK Delta N was constructed and confirmed by DNA sequencing. CD8+ T cells were isolated from C57BL/6 mice, activated in vitro, and then transduced with the hCD19-CAR-MAP3K Delta N vector. For functional analysis, B16-hCD19 tumor-bearing mice were injected with CAR-T cells expressing either wildtype MAP3K (MAP3K-WT) or MAP3KK Delta N, and tumor growth was monitored. Expression of MAP3K-WT improved the tumor-suppression function of hCD19-CAR-T cells. Surprisingly, CAR-T cells expressing MAP3KK Delta N displayed a lower antitumor efficacy than those expressing MAP3K-WT. Furthermore, these results were correlated in vitro, where MAP3KK Delta N showed a response similar to control CAR and reduced tumor inhibition in comparison with MAP3K-WT. Expression of MAP3K-WT, but not MAP3KK Delta N, profoundly improves the antitumor function of CAR-T cells. It is possible that MAP3KK Delta N expression results in T cell overactivation, thereby promoting T cell exhaustion and activation-induced cell death. These results suggest that optimal, rather than excessive, T cell activation is critical for potential therapeutic applications using MAP3K expression. However, it is also possible that deletion of the N-terminal portion of MAP3K impairs its facilitation of T cell metabolic functions.en-USThe author of this work is the copyright owner. UH Libraries and the Texas Digital Library have their permission to store and provide access to this work. Further transmission, reproduction, or presentation of this work is prohibited except with permission of the author(s).Poster