Tonic 4-1BB Costimulation in Chimeric Antigen Receptors Impedes T Cell Survival and Is Vector-Dependent

• Published in: Cell reports (Cambridge) Vol. 21; no. 1; pp. 17 - 26
• Main Authors: Gomes-Silva, Diogo, Mukherjee, Malini, Srinivasan, Madhuwanti, Krenciute, Giedre, Dakhova, Olga, Zheng, Yueting, Cabral, Joaquim M.S., Rooney, Cliona M., Orange, Jordan S., Brenner, Malcolm K., Mamonkin, Maksim
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 03.10.2017; Elsevier
• Subjects: 4-1BB; 4-1BB Ligand - genetics; 4-1BB Ligand - immunology; adoptive T cell therapy; Animals; Antigens, Neoplasm - genetics; Antigens, Neoplasm - immunology; Cell Death; Cell Survival; chimeric antigen receptor; costimulation; fas Receptor - genetics; fas Receptor - immunology; Gammaretrovirus - genetics; Gammaretrovirus - metabolism; Gene Expression Regulation, Leukemic; Genetic Vectors - chemistry; Genetic Vectors - metabolism; Humans; Lentivirus - genetics; Lentivirus - metabolism; Leukemia-Lymphoma, Adult T-Cell - genetics; Leukemia-Lymphoma, Adult T-Cell - immunology; Leukemia-Lymphoma, Adult T-Cell - pathology; Mice; Mice, Inbred NOD; Mutant Chimeric Proteins - genetics; Mutant Chimeric Proteins - immunology; Neoplasm Transplantation; NF-kappa B - genetics; NF-kappa B - immunology; Receptors, Antigen, T-Cell - genetics; Receptors, Antigen, T-Cell - immunology; Signal Transduction; T cells; T-Lymphocytes - immunology; T-Lymphocytes - pathology; T-Lymphocytes - transplantation; Tumor Necrosis Factor Receptor Superfamily, Member 9 - genetics; Tumor Necrosis Factor Receptor Superfamily, Member 9 - immunology; adoptive T cell therapy; 4-1BB; chimeric antigen receptor; costimulation; T cells
• ISSN: 2211-1247; 2211-1247
• DOI: 10.1016/j.celrep.2017.09.015

Antigen-independent tonic signaling by chimeric antigen receptors (CARs) can increase differentiation and exhaustion of T cells, limiting their potency. Incorporating 4-1BB costimulation in CARs may enable T cells to resist this functional exhaustion; however, the potential ramifications of tonic 4-1BB signaling in CAR T cells remain unclear. Here, we found that tonic CAR-derived 4-1BB signaling can produce toxicity in T cells via continuous TRAF2-dependent activation of the nuclear factor κB (NF-κB) pathway and augmented FAS-dependent cell death. This mechanism was amplified in a non-self-inactivating gammaretroviral vector through positive feedback on the long terminal repeat (LTR) promoter, further enhancing CAR expression and tonic signaling. Attenuating CAR expression by substitution with a self-inactivating lentiviral vector minimized tonic signaling and improved T cell expansion and anti-tumor function. These studies illuminate the interaction between tonic CAR signaling and the chosen expression platform and identify inhibitory properties of the 4-1BB costimulatory domain that have direct implications for rational CAR design. [Display omitted] •Tonic 4-1BB signaling in CARs causes T cell apoptosis, impeding antitumor activity•Tonic 4-1BB signaling enhances CAR expression from gammaretroviral LTR promoters•Reducing CAR expression in retro- or SIN lentiviral vectors attenuates this toxicity Gomes-Silva et al. model tonic signaling from chimeric antigen receptors (CARs) harboring the 4-1BB endodomain and describe a mechanism through which this signaling produces toxicity in T cells. CAR-driven tonic 4-1BB signaling activates the LTR promoter in gammaretroviral vectors, thus further amplifying the toxicity and undermining CAR T cell anti-tumor activity.