Nano-delivery of Silibinin Potentiate the Induction of Immunogenic Cell Death (ICD) in Melanoma Cells

Background Induction of immunogenic cell death (ICD) in tumors can enhance antitumor immunity and modulate immunosuppression in the tumor microenvironment (TME).Objective In the current study, we investigated the effect of silibinin, a natural compound with anticancer activity, and its polymer-based nanoformulations on the induction of apoptosis and ICD in cancer cells.Methods Free and nanoparticulate silibinin were evaluated for their growth-inhibitory effects using an MTT assay. Annexin V/PI staining was used to analyze apoptosis. Calreticulin (CRT) expression was measured by flow cytometry. Western blotting was conducted to examine the levels of elf2 alpha, which plays a role in the ICD pathway. The HSP90 and ATP levels were determined using specific detection kits.Results Compared to the free drug, silibinin-loaded nanocarriers significantly increased the induction of apoptosis and ICD in B16F10 cells. ICD induction was characterized by significantly increased levels of ICD biomarkers, including CRT, HSP90, and ATP. We also observed an increased expression of p-elf-2 alpha/ elf-2 alpha in B16F10 cells treated with silibinin-loaded micelles compared to cells that received free silibinin.Conclusion Our findings showed that the encapsulation of silibinin in polymeric nanocarriers can potentiate the effects of this drug on the induction of apoptosis and ICD in B16F10 melanoma cells.