CAR-engineered lymphocyte persistence is governed by a FAS ligand–FAS autoregulatory circuit
Fei Yi, Tal Cohen, Natalie Zimmerman, Friederike Dündar, Paul Zumbo, Razan Eltilib, Erica J. Brophy, Hannah Arkin, Judith Feucht, Michael V. Gormally, Christopher S. Hackett, Korbinian N. Kropp, Iñaki Etxeberría, Smita S. Chandran, Zeguo Zhao, Winson Cai, Anthony F. Daniyan, Jae H. Park, Caleb A. Lareau, Katharine C. Hsu, Michel Sadelain, Doron Betel, Christopher A. Klebanoff
Abstract
Chimeric antigen receptor (CAR)-engineered lymphocytes treat B cell malignancies; however, limited persistence can restrain the full therapeutic potential of this approach. FAS ligand (FAS-L)/FAS interactions govern lymphocyte homeostasis. Knowledge of which cells express FAS-L in patients with cancer and whether these sources compromise CAR persistence remains incomplete. Here, we constructed a single-cell atlas of diverse cancers to identify cellular subsets expressing FASLG, the gene encoding FAS-L. We discovered that FASLG expression is limited primarily to endogenous T cells, natural killer (NK) cells and CAR-T cells, while tumor and stromal cell expression is minimal. To establish whether CAR-T and CAR-NK cell survival is FAS-L regulated, we performed competitive fitness assays using FAS-dominant negative receptor (ΔFAS)-modified lymphocytes. Following transfer, ΔFAS-expressing CAR-T/CAR-NK cells became enriched, a phenomenon that mechanistically was reverted through FASLG knockout. By contrast, FASLG was dispensable for CAR-mediated tumor killing. In multiple models in female mice, ΔFAS coexpression enhanced antitumor efficacy. Together, these findings reveal that CAR-engineered lymphocyte persistence is governed by a FAS-L/FAS autoregulatory circuit.