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 elf2α, 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-2α/ elf-2α 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.