Photodynamic therapy induces pyroptosis via GSDMD pathway in NCI-H226 human lung squamous carcinoma cells

Photodynamic therapy (PDT) is a promising minimally invasive anticancer strategy with high tumor-targeting specificity, attracting considerable attention in oncology. Pyroptosis, a pro-inflammatory programmed cell death (PCD) mediated by the gasdermin (GSDM) family, is tightly regulated by the gasdermin D (GSDMD)-dependent pathway and contributes to tumor regulation. However, the molecular mechanism of PDT-induced pyroptosis in lung squamous cell carcinoma (LUSC) NCI-H226 cells remains unclear. Herein, we demonstrated that PDT effectively triggers GSDMD-mediated pyroptosis in NCI-H226 cells, with typical morphological features including cytoplasmic bubble formation, membrane rupture, intracellular content release and pro-inflammatory mediator secretion. Mechanistically, PDT-induced pyroptosis involves NLRP3 inflammasome upregulation, caspase-1 activation and GSDMD cleavage to generate GSDMD-N, key events driving pyroptosis. PDT treatment significantly enhanced lactate dehydrogenase (LDH) release and secretion of pro-inflammatory cytokines including IL-1β and IL-18. Notably, GSDMD silencing or caspase-1 inhibition with VX765 markedly abrogated PDT-induced pyroptosis. Collectively, PDT induces pyroptosis in NCI-H226 cells via the NLRP3-caspase-1-GSDMD axis. This study reveals a novel anti-tumor mechanism of PDT in LUSC, providing a theoretical basis and potential therapeutic targets for clinical LUSC management.