Background: Glioblastoma is a common primary malignant tumor posing a serious threat to human life and health. Protocatechuic acid (PCA) is a natural phenolic compound with good anti-tumor activity. The study aimed to investigate whether pyroptosis can be activated by PCA in glioma cell.

Methods: Different concentrations of PCA were used to treat glioma cell lines U87 and U251 for varying durations. Cell proliferation was quantified using the Cell Counting Kit-8 (CCK-8) assay. The Transwell chamber assay was employed to evaluate cell invasion, while cell migration was assessed via the scratch assay. Pyroptosis levels were determined through immunofluorescence staining. Additionally, the protein and mRNA expression levels of nucleotide-binding and oligomerization domain-like receptor thermal protein domain-associated protein 3 (NLRP3), cysteinyl aspartate specific proteinase (caspase-1), and gasdermin D (GSDMD) were analyzed using Western blotting and quantitative reverse-transcription polymerase chain reaction (qRT-PCR).

Results: Intervention with PCA resulted in a significant suppression of viability, invasion and migration of glioma cells in a dose-dependent manner (p < 0.05). Additionally, the GSDMD positivity rate, as well as the protein and mRNA expression levels of NLRP3, caspase-1, and GSDMD showed significant increases in glioma cells (p < 0.05). Further intervention with NLRP3-specific inhibitor MCC950 reversed the effects of PCA and resulted in a significant increase in cell viability and number of invading cells (p < 0.01), a significant decrease in GSDMD positivity (p < 0.01), and a significant decrease in the protein and mRNA expression levels of NLRP3, caspase-1, and GSDMD in glioma cells (p < 0.01).

Conclusion: PCA mediates pyroptosis in glioma cells by regulating the NLRP3/caspase-1/GSDMD signaling pathway.