Hybrid Cell Membrane-Coated Nanoparticles for Synergizing Sonodynamic Therapy and Immunotherapy against Triple-Negative Breast Cancer.

Tumor immunotherapy represents a highly promising modality for the treatment of triple-negative breast cancer (TNBC). Nevertheless, its therapeutic efficacy has been profoundly impacted by challenges such as low drug uptake, hypoxia, and immunosuppression. To address these problems, the study develops a strategy combining sonodynamic therapy (SDT) and immunotherapy using biomimetic nanoparticles coated with hybrid membranes. The nanoparticles are loaded with semiconducting polymers (PFODBT), Atovaquone (ATO), and TMP195 to enhance biocompatibility, targeting ability, and drug uptake and retention at the tumor site. In in vitro experiments, the biomimetic nanoparticles alleviate hypoxia, induce immunogenic cell death (ICD), and prompt reprogramming of tumor-associated macrophages (TAMs) from M2 type to M1 type. In in vivo experiments, the synergistic effects of enhanced SDT-mediated ICD and TAMs repolarization significantly inhibit the proliferation of primary and distant tumor in the 4T1 subcutaneous tumor model, and effectively attenuated metastasis of lung and liver. Moreover, the in vivo immune responses are further activated by improving the maturation of dendritic cells, filtration of CD8⁺ T cells, and depletion of regulatory T cells. This study offers a novel strategy for TNBC therapy by converting the tumor microenvironment from the "cold" into "hot" tumor through multiple synergistic therapies.