Focused Acoustic Vortex-Activated Dual-Stimuli Nanoplatform Synergizes with Checkpoint Blockade to Enhance Macrophage Phagocytosis and Antitumor Immunity.

Abstract

Macrophage activation in tumor immunotherapy is hindered by the "do not eat me" evasion mechanism, mediated by the CD47-SIRPα axis. Current therapeutic strategies that solely block antiphagocytic signals show limited efficacy in solid tumors, indicating the urgent need to simultaneously enhance "eat me" signals. To this end, we developed a focused acoustic vortex (FAV)-triggered dual-stimuli-responsive nanoplatform to enhance macrophage phagocytosis. This nanoplatform consists of a liposome coloaded with Cas9/sgRNA complexes and the sonosensitizer chlorin e6 (Ce6), enabling a FAV-triggered activation cascade. Upon FAV exposure, this system facilitates (1) enhanced cellular uptake by increasing membrane permeability through cavitation; (2) activation of Ce6 to generate reactive oxygen species, inducing calreticulin exposure to enhance "eat-me" signals; and (3) disruption of endosomes/lysosomes to release the Cas9/sgRNA complexes for CD47-specific knockout. This strategy enhanced macrophage phagocytosis of tumor cells, promoted M2-to-M1 macrophage polarization, and activated T-cell-mediated immune responses, resulting in significant antitumor efficacy in the 4T1-tumor-bearing mouse model. Programmed death-ligand 1 (PD-L1) checkpoint blockade following nanoplatform activation amplified systemic immune responses, resulting in 90% inhibition of primary and 80% inhibition of distant 4T1 tumors, and long-term immune memory. This study presents a strategy for precision immunotherapy through spatiotemporally controlled modulation of phagocytic signaling pathways.