Trispecific natural killer cell nanoengagers for targeted chemoimmunotherapy.

Activation of the innate immune system and natural killer (NK) cells has been a key effort in cancer immunotherapy research. Here, we report a nanoparticle-based trispecific NK cell engager (nano-TriNKE) platform that can target epidermal growth factor receptor (EGFR)-overexpressing tumors and promote the recruitment and activation of NK cells to eradicate these cancer cells. Moreover, the nanoengagers can deliver cytotoxic chemotherapeutics to further improve their therapeutic efficacy. We have demonstrated that effective NK cell activation can be achieved by the spatiotemporal coactivation of CD16 and 4-1BB stimulatory molecules on NK cells with nanoengagers, and the nanoengagers are more effective than free antibodies. We also show that biological targeting, either through radiotherapy or EGFR, is critical to the therapeutic effects of nanoengagers. Last, EGFR-targeted nanoengagers can augment both NK-activating agents and chemotherapy (epirubicin) as highly effective anticancer agents, providing robust chemoimmunotherapy.