Near-Infrared Light-Responsive Liposomes for Modulating Switchable CAR-T Cell Therapy

Chimeric antigen receptor T (CAR-T) cell therapy has great potential but is limited by off-target effects and cytokine release syndrome. To address these challenges, we developed a mesothelin-targeted switchable CAR-T cell system whose activity can be externally controlled by near-infrared (NIR) light-responsive liposomes.

We constructed mesothelin-targeted switchable CAR-T cells via lentiviral transduction. A NIR-responsive liposomal formulation was prepared to encapsulate a small-molecule switch agent (rapamycin or AP21967) for controlled release upon NIR irradiation. By encapsulating a NIR-triggerable photosensitizer, the liposomes became photo-labile, and exposure to 730 nm light induced lipid peroxidation, consequently allowing drug release. The switchable CAR-T cells were co-cultured with mesothelin-expressing ovarian cancer cells (OVCAR-3) under various conditions, with or without NIR irradiation. Cytotoxicity was assessed by LDH release assay, and cytokine secretion (TNF-α and IL-2) was measured by ELISA.

The switchable CAR-T cells exhibited minimal baseline cytotoxicity in the absence of the inducing agent. Upon NIR irradiation, the liposomes released the encapsulated switch agent, which activated the CAR-T cells in a concentration-dependent manner. NIR-triggered activation significantly enhanced the secretion of TNF-α and IL-2 and potentiated the killing effect against mesothelin-positive ovarian cancer cells in vitro.

Our findings demonstrate that the combination of switchable CAR-T technology with NIR-responsive liposomes enables spatiotemporally controlled CAR-T activation, offering a potential strategy to mitigate off-target toxicity and facilitating the clinical application of CAR-T therapy in solid tumors.