Background:Immunotherapy becoming the focus of contemporary multidisciplinary collaborative research efforts towards advanced hepatocellular carcinoma (HCC).
Objective:This study aims to develop a nanobubble (NB) delivery system designed to co-administer an immunogenic cell death (ICD) inducer, Shikonin (SK), alongside an immune checkpoint inhibitor, miR-497-5p, to enhance the efficacy of the immune response against liver cancer.
Methods:
NBs were synthesized through thin-film hydration and mechanical oscillation techniques to encapsulate miR-497 and SK. Comprehensive characterization and pharmacokinetic analyses of the miR-497/SK-loaded NBs were conducted both
in vitro
and
in vivo
. To evaluate the anti-tumor efficacy and immunological activity of this combination therapy, a subcutaneous transplanted tumor model using H22 hepatoma cells was established.
Results:
The miR-497/SK-NBs demonstrated an optimal morphology and size, as well as excellent gene capacity and SK encapsulation. The
in vivo
anti-tumor effects and mechanisms of SK and miR-497 were assessed in H22 hepatoma transplants model. The miR-497/SK-NBs group showed the strongest tumor inhibition, with their synergistic immunotherapeutic effect demonstrated through two main mechanisms. Initially, the activation of SK, facilitated by ultrasound, triggered the induction of injury-related molecular patterns, including CRT and HMGB1. This process subsequently activated CD80
+
CD86
+
macrophages, thereby enhancing the presentation of tumor antigens. Subsequently, miR-497 contributed to the downregulation of PD-L1 expression in tumor cells. Collectively, these processes elicited a robust systemic anti-tumor immune response and induced apoptosis in tumor cells within murine HCC models.
Conclusions:The study demonstrated that miR-497/SK-loaded nanobubbles simultaneously boosts ICD and blocks the PD-1/PD-L1 pathway in immunotherapy. This finding offers a theoretical foundation for the effective eradication of tumor cells and the development of a highly efficient synergistic treatment strategy for HCC.
