Anti-Her2 CAR-NK92 Cells and Their Exosomes: Generation, Characterization, and Selective Cytotoxicity Against Her2-Positive Tumor Cells

Chimeric antigen receptor (CAR)-engineered NK cells are a promising approach for targeted immunotherapy in Her2-positive cancers. This study aimed to generate anti-Her2 CAR-NK92 cells, to evaluate their selective cytotoxicity against Her2-positive cancer cells, and to isolate and characterize their released exosomes. NK92 cells were electroporated with piggyBac transposon vectors encoding anti-Her2 CAR and the helper transposase. Puromycin selection was performed to enrich the transduced cells. CAR and GFP expression were assessed by flow cytometry, and exosomes were isolated and characterized in terms of protein cargo and surface protein expression. Cytotoxicity was evaluated using real-time cell analysis against Her2-positive SK-BR3 cells and Her2-negative MCF-7 cells. Electroporation did not significantly affect NK92 cell viability. Puromycin selection efficiently enriched for CAR-expressing cells, with GFP positivity reaching 99.8% and a 15-fold increase in CAR surface expression compared to wild-type cells. CAR-NK92 cells demonstrated robust, Her2-specific cytotoxicity in a E:T-dependent manner, with the greatest effect observed at a 10:1 effector-to-target ratio. Exosomes derived from CAR-NK92 cells contained CAR molecules and selectively targeted Her2-positive cells. Anti-Her2 CAR-NK92 cells and their exosomes exhibit potent and selective cytotoxicity against Her2-positive cancer cells, supporting their potential as innovative immunotherapeutic agents for solid tumors.