Dual CAR-Targeted Natural Killer Cell Lines Demonstrate Potent Cytotoxic Properties Towards Breast Cancer Cells

Reducing the incidence of side effects from T-cell and NK-cell immunotherapy with chimeric receptors requires precise targeting of effector cells to tumor cell populations. Most malignant neoplasms do not express unique tumor neoantigens; therefore, it may be necessary to use the recognition of a combination of several surface molecules for targeting. Recognition of antigen combinations using paired CARs requires the introduction of extended expression constructs into effector cells, which limits the use of lentiviral vectors as transduction vessels. To overcome this limitation, we tested paired CARs containing antigen-recognizing sequences based on camelid single-domain antibodies, which are characterized by relatively small size and high specificity and affinity properties. Paired CARS containing activating-co-stimulatory, or activating-inhibiting receptors were tested on cell cultures of triple-negative breast cancer, which conferred that this strategy allows targeting of immune cells, in particular linear natural killer cells, to highly malignant subpopulations of cancer cells.