The Mechanism Of The Activation Of GSDME During Cancer Cell Pyroptosis Induced By Anti-cancer Drugs

Pyroptosis is a form of lytic programmed cell death that is characterized by swelling,membrane rupture and blowing bubbles.Previous studies showed that microbial infection could activate pro-inflammatory csapase and induce pyroptosis.Recent studies indicated that pro-apoptotic caspase could also cleave and activate GSDME to induce pyroptosis.Previous studies have shown that many chemotherapy treatments induce apoptosis through BAK/BAX-dependent mitochondrial pathway.BAK/BAX activation causes the mitochondrial outer membrane permeabilization(MOMP),thereby inducing the activation of pro-apoptotic caspase cascade.A recent study indicated that GSDME cleavage by the pro-apoptotic caspases determines whether chemotherapy drug treatments induce apoptosis or pyroptosis,however,its regulation mechanisms are not clear.More importantly,post-translational modifications of GSDME and its effects on pyroptosis regulation,especially on the determination of cell death,have not been studied.In this study,we showed that TNF?+CHX and navitoclax induced cancer cell pyroptosis through a BAK/BAX-caspase-3-GSDME signaling pathway.GSDME knockdown inhibited the pyroptosis,suggesting the essential role of GSDME in this process.Interestingly,GSDME was found to be palmitoylated on its C-terminal(GSDME-C)during chemotherapy induced pyroptosis,while 2-bromopalmitate(2-BP)could inhibit the palmitoylation of GSDME-C and chemotherapy induced pyroptosis.Mutation of palmitoylation sites on GSDME also diminished the pyroptosis induced by chemotherapy drugs.Moreover,2-BP treatment enhanced the interaction between GSDME-C and GSDME-N,providing a potential mechanism of this function.Further studies indicated several ZDHHC proteins including ZDHHC-2,7,11,15 could interact with and palmitoylate GSDME.In conclusion,our findings not only enriched our understanding for pyroptosis pathway but also offered new targets to achieve the transformation between chemotherapy-induced pyroptosis and apoptosis.