Miltirone induces cell death in hepatocellular carcinoma cell through GSDME-dependent pyroptosis

Pyroptosis is a form of programmed cell death,and recently described as a new molecular mechanism of chemotherapy drugs in the treatment of tumors.Miltirone,a derivative of phenanthrenequinone isolated from the root of Salvia miltiorrhiza Bunge,has been shown to possess anti-cancer activities.Here,we found that miltirone inhibited the cell viability of either HepG2 or Hepa1-6 cells,and induced the proteolytic cleavage of gasdermin E(GSDME)in each hepatocellular carcinoma(HCC)cell line,with concomitant cleavage of caspase 3.Knocking out GSDME switched miltirone-induced cell death from pyroptosis to apoptosis.Additionally,the induction effects of miltirone on GSDMEdependent pyroptosis were attenuated by si RNA-mediated caspase three silencing and the specific caspase three inhibitor Z-DEVD-FMK,respectively.Miltirone effectively elicited intracellular accumulation of reactive oxygen species(ROS),and suppressed phosphorylation of mitogen-activated and extracellular signal-regulated kinase(MEK)and extracellular regulated protein kinases 1/2(ERK1/2)for pyroptosis induction.Moreover,miltirone significantly inhibited tumor growth and induced pyroptosis in the Hepa1-6 mouse HCC syngeneic model.These results provide a new insight that miltirone is a potential therapeutic agent for the treatment of HCC via GSDME-dependent pyroptosis.