Mitochondria-Targeted Icaritin Nanoparticles Induce Immunogenic Cell Death in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a highly malignant tumor that is resistant to chemotherapy and immunotherapy. Icaritin (ICT), a traditional Chinese medicine, has been reported as an immunoregulatory agent for treating advanced unresectable HCC. ICT induces mitophagy to cause immunogenic cell death (ICD); however, the poor bioavailability of ICT limits its therapeutic efficacy and clinical use. Therefore, this study aimed to assess the effect of using the poly(2-(N-oxide-N,N-diethylamino) ethyl methacrylate)-b-poly(ε-caprolactone) copolymer (OPDEA-PCL) to encapsulate ICT into nanoparticles (ICT NPs). OPDEA-PCL/ICT NPs colocalized with the mitochondria, promoting the ICD induction effect of ICT in mouse HCC H22 cells. In the H22 subcutaneous tumor model, intravenously injected OPDEA-PCL/ICT NPs quickly accumulated in the tumor and efficiently activated systemic anticancer immunogenicity through their effects on mitophagy. The resulting tumor suppression rate was 60%, which was significantly higher than that of free ICT and poly(ethylene glycol) (PEG)-PCL/ICT NPs. Furthermore, mouse survival was also prolonged by nearly 2-fold with OPDEA-PCL/ICT NPs compared with PBS. In summary, this approach provides valuable insights into improving the immunotherapeutic efficacy of ICT for HCC.