Juglone induces GSDME-mediated pyroptosis by targeting HSP90α ATPase domain to promote STAT3 degradation in glioblastoma multiforme.

Abstract

Glioblastoma (GBM) is a highly aggressive primary brain tumor with grim overall median survival, and its therapeutic efficacy is severely limited due to drug resistance. Therefore, developing effective and safe chemotherapy regimens is urgently required. Juglone, a natural bioactive constituent derived from traditional Chinese herbs, has emerged as a promising therapeutic agent against various human malignancies. However, the direct molecular target and the mechanisms against GBM remain poorly defined. Herein, we demonstrated that juglone exhibited anti-GBM activity both in vitro and in vivo by selectively inducing GSDME-mediated pyroptosis, but not canonical GSDMD-mediated pyroptosis. Genetic ablation of GSDME or pharmacological inhibition of caspase-3 significantly abolished juglone-elicited pyroptotic cell death. Mechanistically, juglone induced mitochondrial fission and subsequent mtROS production, which constituted a positive regulatory loop to initiate caspase-3/GSDME-mediated pyroptosis. Furthermore, combining network pharmacology, ATPase activity assay, cellular thermal shift assay (CETSA), and co-immunoprecipitation, we identified HSP90α as a direct binding target of juglone, with the binding interface localized to the ATP-binding pocket of HSP90α. Further mechanistic analysis revealed that juglone disrupted the HSP90α-STAT3 interaction, facilitating ubiquitin-proteasome-dependent STAT3 degradation and concurrently elevating oxidative stress. In summary, our study uncovered a regulatory axis linking juglone to the HSP90α/STAT3 signaling, which governs mtROS-driven pyroptosis in GBM cells. As a novel HSP90α ATPase inhibitor, juglone represents a promising natural therapeutic candidate for GBM intervention.