Ultrasound Molecular Imaging Enhances High‐Intensity Focused Ultrasound Ablation on Liver Cancer With B7‐H3‐Targeted Microbubbles

ABSTRACT Background High‐intensity focused ultrasound (HIFU) is a promising minimally invasive treatment for liver cancer; however, its efficacy is often limited by the attenuation of ultrasonic energy. This study investigates the effectiveness of B7‐H3‐targeted microbubbles (T‐MBs) in enhancing HIFU ablation of liver cancer and explores their potential for clinical translation. Methods T‐MBs and isotype control microbubbles (I‐MBs) were synthesized through the conjugation of biotinylated anti‐B7‐H3 antibody and isotype control antibody to the microbubble surface, respectively. Contrast‐enhanced ultrasound imaging was performed to compare the accumulation of T‐MBs and I‐MBs in liver cancer at various time points. The efficacy of T‐MBs in enhancing HIFU treatment was evaluated by measuring the immediate tumor ablation rate and long‐term tumor growth suppression. Additionally, the induced antitumor immune response was assessed through cytokine quantification in serum and tumor tissue, along with immunofluorescence staining conducted on days 1, 3, and 7 post‐treatment. Results T‐MBs demonstrated superior liver cancer‐specific accumulation, characterized by higher concentrations and prolonged retention compared to I‐MBs. The combination of T‐MBs with HIFU resulted in significantly enhanced tumor ablation rates and superior tumor growth suppression. Post‐treatment analysis revealed a gradual uptick in cytokine levels within the tumor microenvironment, along with progressive infiltration of antitumor immune cells. Conclusion T‐MBs effectively enhance the therapeutic efficacy of HIFU for liver cancer treatment while simultaneously promoting an antitumor immune response. These findings provide a strong experimental foundation for the clinical translation of ultrasound molecular imaging combined with HIFU as a novel approach for tumor therapy.