Decoding phillygenin's dual attack on breast cancer: ferroptosis induction and immune evasion suppression.

Ferroptosis and immune evasion are pivotal mechanisms in the pathogenesis of breast cancer (BC), making them promising therapeutic targets. Phillygenin (PHI), a lignan compound derived from Forsythiae Fructus, has demonstrated broad pharmacological properties, including anti-tumor effects. To discuss the impact of PHI on BC. The study examined PHI's anti-tumor properties and mechanisms using CCK-8 assays, biochemical analyses, DCHF-DA staining, ELISA, immunofluorescence, and western blot techniques. Tumor-bearing mice were utilized for studies in vivo, with tumor tissues being analyzed by H&E staining, immunohistochemistry, and western blotting. The viability of MDA-MB-231 and MCF7 cells was notably repressed by PHI, with respective IC50 values of 81.44 µM and 95.72 µM. PHI elevated intracellular Fe levels, an effect synergistically enhanced by erastin but attenuated by ferrostatin-1. Furthermore, PHI increased reactive oxygen species (ROS) levels while downregulating GPX4 and SLC7A11 expression in both cell lines. PHI also enhanced CD8 T cell cytotoxicity and upregulated IFN-γ and IL-2 levels, but suppressing PD-L1 expression. Mechanistically, PHI repressed the phosphorylation of AKT and GSK3β, along with the β-catenin expression, effects that were reversed by the AKT activator SC79. SC79 also counteracted PHI-induced changes in proliferation, ferroptosis, and immune evasion markers in MDA-MB-231 cells. PHI decreased tumor size and mass, lowered GPX4, p-AKT/AKT, p-GSK3β/GSK3β, and β-catenin levels, and elevated IFN-γ levels in MDA-MB-231 xenograft models. PHI inhibited BC cell proliferation and immune evasion while promoting ferroptosis through suppression of the AKT/β-catenin axis, highlighting its possible as a therapeutic agent for BC.