Engineering sonogenetic EchoBack-CAR T cells

Chimeric antigen receptor (CAR) T cell therapy for solid tumors encounters challenges such as on-target off-tumor toxicity, exhaustion, and limited T cell persistence. Here, we engineer sonogenetic EchoBack-CAR T cells using an ultrasensitive heat-shock promoter screened from a library and integrated with a positive feedback loop from CAR signaling, enabling long-lasting CAR expression upon focused-ultrasound (FUS) stimulation. EchoBack-hGD2CAR T cells, targeting disialoganglioside GD2, exhibited potent cytotoxicity and persistence in 3D glioblastoma (GBM) models. In mice, EchoBack-hGD2CAR T cells suppressed GBM without off-tumor toxicity and outperformed their constitutive counterparts. Single-cell RNA sequencing revealed enhanced cytotoxicity and reduced exhaustion in EchoBack-CAR T cells compared with the standard CAR T cells. This EchoBack design was further adapted to target prostate-specific membrane antigen (EchoBack-PSMACAR) for prostate cancer treatment, demonstrating long-lasting tumor suppression with minimal off-tumor toxicity. Thus, the sonogenetic EchoBack-CAR T cells can serve as a versatile, efficient, and safe strategy for solid tumor treatment.