Targeted Ultrasound Nanobubbles Therapy for Prostate Cancer via Immuno-Sonodynamic Effect

Background: Prostate cancer (PCa) poses a significant global health threaten. Immunotherapy has emerged as a novel strategy to augment the inhibition of tumor proliferation. However, the sole use of anti-PD-L1 Ab for PCa has not yielded improvements, mirroring outcomes observed in other tumor types. Methods: This study employed the thin film hydration method to develop lipid nanobubbles (NBs) encapsulating chlorin e6 (Ce6) and anti-PD-L1 Ab (Ce6@aPD-L1 NBs). Our experimental approach included cellular assays and mouse immunization, providing a comprehensive evaluation of Ce6@aPD-L1 NBs' impact. Results: The Ce6@aPD-L1 NBs effectively induced reactive oxygen species generation, leading to tumor cells death. In mice, they demonstrated a remarkable enhancement of immune responses compared to control groups. These immune responses encompassed immunogenic cell death induced by sonodynamic therapy and PD-1/PD-L1 blockade, activating dendritic cells maturation and effectively stimulating CD8+T cells. Conclusion: Ce6@aPD-L1 NBs facilitate tumor-targeted delivery, activating anti-tumor effects through direct sonodynamic therapy action and immune system reactivation in the tumor microenvironment. Ce6@aPD-L1 NBs exhibit substantial potential for achieving synergistic anti-cancer effects in PCa. Keywords: Ce6, nanobubbles, ultrasound, sonodynamic therapy, immunotherapy