TY - JOUR
T1 - Reversible transgene expression reduces fratricide and permits 4-1BB Costimulation of CAR T cells directed to T-cell malignancies
AU - Mamonkin, Maksim
AU - Mukherjee, Malini
AU - Srinivasan, Madhuwanti
AU - Sharma, Sandhya
AU - Gomes-Silva, Diogo
AU - Mo, Feiyan
AU - Krenciute, Giedre
AU - Orange, Jordan S.
AU - Brenner, Malcolm
N1 - Publisher Copyright:
©2017 American Association for Cancer Research.
PY - 2018/1
Y1 - 2018/1
N2 - T cells expressing second-generation chimeric antigen receptors (CARs) specific for CD5, a T-cell surface marker present on normal and malignant T cells, can selectively kill tumor cells. We aimed to improve this killing by substituting the CD28 costimulatory endodomain (28.z) with 4-1BB (BB.z), as 28.z CD5 CART cells rapidly differentiated into short-lived effector cells. In contrast, 4-1BB costimulation is known to promote development of the central memory subpopulation. Here, we found BB.z CD5 CAR T cells had impaired growth compared with 28.z CD5.CAR T cells, due to increased T-cell-T-cell fratricide. We demonstrate that TRAF signaling from the 4-1BB endodomain upregulated the intercellular adhesion molecule 1, which stabilized the fratricidal immunologic synapse between CD5 CAR T cells. As the surviving BB.z CD5 CAR T cells retained the desired central memory phenotype, we aimed to circumvent the 4-1BB-mediated toxicity using a regulated expression system that reversibly inhibits CAR expression. This system minimized CAR signaling and T-cell fratricide during in vitro expansion in the presence of a small-molecule inhibitor, and restored CAR expression and antitumor function of transduced T cells in vivo. These studies reveal a mechanism by which 4-1BB costimulation impairs expansion of CD5 CAR T cells and offer a solution to mitigate this toxicity.
AB - T cells expressing second-generation chimeric antigen receptors (CARs) specific for CD5, a T-cell surface marker present on normal and malignant T cells, can selectively kill tumor cells. We aimed to improve this killing by substituting the CD28 costimulatory endodomain (28.z) with 4-1BB (BB.z), as 28.z CD5 CART cells rapidly differentiated into short-lived effector cells. In contrast, 4-1BB costimulation is known to promote development of the central memory subpopulation. Here, we found BB.z CD5 CAR T cells had impaired growth compared with 28.z CD5.CAR T cells, due to increased T-cell-T-cell fratricide. We demonstrate that TRAF signaling from the 4-1BB endodomain upregulated the intercellular adhesion molecule 1, which stabilized the fratricidal immunologic synapse between CD5 CAR T cells. As the surviving BB.z CD5 CAR T cells retained the desired central memory phenotype, we aimed to circumvent the 4-1BB-mediated toxicity using a regulated expression system that reversibly inhibits CAR expression. This system minimized CAR signaling and T-cell fratricide during in vitro expansion in the presence of a small-molecule inhibitor, and restored CAR expression and antitumor function of transduced T cells in vivo. These studies reveal a mechanism by which 4-1BB costimulation impairs expansion of CD5 CAR T cells and offer a solution to mitigate this toxicity.
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U2 - 10.1158/2326-6066.CIR-17-0126
DO - 10.1158/2326-6066.CIR-17-0126
M3 - Article
C2 - 29079655
AN - SCOPUS:85040458768
SN - 2326-6066
VL - 6
SP - 47
EP - 58
JO - Cancer immunology research
JF - Cancer immunology research
IS - 1
ER -