Ferroptosis contributes to the inhibition of the growth of hepatocellular carcinoma cells treated with polyphyllin VI. (A and B) Representative transmission electron microscopy images of HCCLM3 and Huh7 cells treated with the indicated concentrations of PPVI for 24 h. HCCLM3 and Huh7 cells were treated with or without 3-MA, Ac-DEVD-CHO and Fer-1 inhibitors for 2 h prior to treatment with PPVI for 24 h, and then subjected to different assays. (C and D) Analysis of cell viability. (E and F) Results of LDH assay. (G and H) Changes in the MMP of HCCLM3 and Huh7 cells treated with increasing PPVI concentrations were observed by detection with JC-1. Red fluorescence indicates a high MMP, whereas green fluorescence indicates a low MMP. **P<0.01, ***P<0.001 and ****P<0.0001 vs. control. NS, not significant; Con, control; MMP: mitochondrial membrane potential; PPVI, polyphyllin VI; Fer-1, ferrostatin-1; 3-MA, 3-methyladenine.