Berberine shaping the tumor immune landscape via pyroptosis.

Pyroptosis is a programmed cell death (PCD) mainly mediated by the Gasdermin family of proteins, among which Gasdermin E (GSDME) is considered a tumor suppressor gene. GSDME can recruit immune cells to the tumor microenvironment (TME) and promote their effects. Activating and enhancing adaptive immunity through GSDME is a potential solution for anti-tumor therapy. Here we reported that berberine (BBR), a small molecule from traditional Chinese medicine, as a GSDME activator, induced caspase-3 (C-3)/GSDME pathway-mediated pyroptosis through the mitochondrial pathway, improved the immunosuppressive state of the tumor microenvironment, and thus promoted anti-tumor immunity. We determined the induction of pyroptosis of 4 T1 cells by BBR through various experiments, and investigated the immune activation effect of BBR by co-culture in vitro, which induced DCs maturation and macrophage polarization. Zebrafish embryo toxicity experiments were used to evaluate the in vivo safety of berberine. Furthermore, the in vivo antitumor and immune activation effects of BBR were investigated using 4 T1 orthotopic model mice, and the results showed that BBR could eliminate orthotopic tumor cells by activating local and systemic immunity. Moreover, we observed that BBR significantly inhibited breast cancer lung metastasis. In summary, our results showd the role of BBR as a GSDME activator stimulated both local and systemic antitumor immune responses by inducing pyroptosis, effectively preventing tumor development and metastasis.