Saquinavir induces pyroptosis through the OTUD5-JAK1-GSDME axis in hepatocellular carcinoma.

Pyroptosis is a newly defined form of programmed cell death characterized by plasma membrane perforation, release of cellular contents, and a robust inflammatory response, thereby sensitizing tumors to existing anticancer therapies. Our study aimed to screen a panel of clinically used antiviral drugs to identify candidate compounds capable of inducing pyroptosis in hepatocellular carcinoma (HCC) cells by evaluating cell viability and monitoring morphological changes. In vitro experiments using two HCC cell lines and xenograft models were established to investigate the mechanism and combined therapeutic efficacy of the candidate drugs. Our results showed that saquinavir (SAQ) significantly inhibited HCC cell proliferation and triggered caspase-3-GSDME dependent pyroptosis. Mechanistically, SAQ significantly blocked glucose metabolism by inhibiting both glycolysis and tricarboxylic acid (TCA) cycles, reducing lactate accumulation and promoting ROS outburst. Additionally, SAQ potently targets the deubiquitinase OTUD5, accelerating the ubiquitin-proteasome mediated degradation of JAK1 and resulting in mitochondria disruption, which further activated the caspase-3-GSDME axis to induce pyroptosis. Furthermore, the combination of SAQ with sorafenib, a first-line therapeutic agent for HCC, exhibited synergistic antitumor activity both in vitro and in the nude mouse model. These findings not only identify SAQ as a novel pyroptosis-inducer, but also clarify the critical role of the OTUD5-JAK1-GSDME axis in resisting pyroptosis, which may further provide experimental evidence and potential new strategies for treating HCC.