MST1 Suppresses Pancreatic Cancer Progression via ROS-Induced Pyroptosis.

Pancreatic ductal adenocarcinoma (PDAC) is a deadly disease, and its incidence is increasing annually. It is critical to reveal and delineate the molecular mechanism promoting PDAC development and progression. Mammalian STE20-like kinase 1 (MST1) is a proapoptotic cytoplasmic kinase and also one of the core components of the Hippo pathway. Here, we showed that MST1 expression was decreased in PDAC, and restored expression of MST1 promoted PDAC cell death and suppressed the proliferation, migration, invasion, and cell spheroid formation of PDAC via caspase-1-induced pyroptosis. Further studies demonstrated that pyroptosis induced by MST1 was independent of the Hippo pathway, but mediated by reactive oxygen species (ROS). And ROS scavenger N-acetyl-cysteine attenuated the activation of caspase-1 induced by MST1 and the effect of MST1 in PDAC cell death, proliferation, migration, and invasion. Collectively, our study demonstrated that MST1 suppressed the progression of PDAC cells at least partly through ROS-induced pyroptosis. IMPLICATIONS: In this study, we identified a new mechanism of MST1 in inhibiting PDAC development and progression and revealed that MST1 would be a potential prognostic and therapeutic target for PDAC. ©2019 American Association for Cancer Research.