Pham-Danis Catherine, Novak Amanda J, Danis Etienne, McClellan Samantha M, Leach Lillie, Yarnell Michael C, Ebmeier Christopher C, Tasian Sarah K, Kohler M Eric
Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA.
Department of Biomedical Informatics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA; Biostatistics & Bioinformatics Shared Resource, University of Colorado Cancer Center, Aurora, CO 80045, USA.
Cancer Cell. 2025 Mar 10;43(3):482-502.e9. doi: 10.1016/j.ccell.2025.02.008.
Chimeric antigen receptor (CAR) T cells induce responses in patients with relapsed/refractory leukemia; however, long-term efficacy is frequently limited by relapse. The inability to target antigen-low cells is an intrinsic vulnerability of second-generation CAR T cells and underlies most relapses following CD22BBz CAR T cell therapy. Here, we interrogate CD22BBz CAR signaling in response to low antigen and find inefficient phosphorylation of the linker for activation of T cells (LAT) limiting downstream signaling. To overcome this, we designed the adjunctive LAT-activating CAR T cell (ALA-CART) platform, pairing a second-generation CAR with a LAT-CAR incorporating the intracellular domain of LAT. ALA-CART cells demonstrate reduced differentiation during manufacturing and increased LAT phosphorylation, MAPK signaling, and AP-1 activity. ALA-CART cells show improved cytotoxicity, proliferation, persistence, and efficacy against antigen-low leukemias that were refractory to clinically active CD22BBz CAR T cells. Restoration of LAT signaling through the ALA-CART platform represents a promising strategy for overcoming multiple mechanisms of CAR T cell failure.
嵌合抗原受体（CAR）T细胞可诱导复发/难治性白血病患者产生应答；然而，长期疗效常受复发限制。无法靶向低表达抗原的细胞是第二代CAR T细胞的固有弱点，也是CD22BBz CAR T细胞治疗后大多数复发的原因。在此，我们研究了CD22BBz CAR对低表达抗原的应答信号，发现T细胞活化连接蛋白（LAT）磷酸化效率低下，限制了下游信号传导。为克服这一问题，我们设计了辅助性LAT激活CAR T细胞（ALA-CART）平台，将第二代CAR与包含LAT胞内结构域的LAT-CAR配对。ALA-CART细胞在制备过程中分化减少，LAT磷酸化、丝裂原活化蛋白激酶（MAPK）信号传导和活化蛋白-1（AP-1）活性增加。ALA-CART细胞对临床上有活性的CD22BBz CAR T细胞难治的低表达抗原白血病显示出增强的细胞毒性、增殖能力、持久性和疗效。通过ALA-CART平台恢复LAT信号传导是克服CAR T细胞失效多种机制的一种有前景的策略。
