Ellagic acid mediated pyroptosis in hepatocellular carcinoma via the ESR1/G6PD pathway

Hepatocellular carcinoma (HCC) is the leading cause of cancer-related morbidity and mortality worldwide. Ellagic acid (EA), a natural polyphenol, has demonstrated antitumor properties, but its precise mechanisms in HCC remain unclear. Here, we mainly explored the pathway of ellagic acid-mediated HCC cell pyroptosis in xenograft nude mice models and two cell lines using flow cytometry, oxidative stress kits, chromatin immunoprecipitation (ChIP), surface plasmon resonance (SPR), cellular thermal shift assay (CETSA), and bioinformatics analysis. The results showed that in HCC cells, ellagic acid inhibited the proliferation and migration of tumor cells, promoted intracellular oxidative stress, and activated cell pyroptosis signals, but had no significant effect on cell apoptosis and necroptosis. The transcription factor estrogen receptor 1 (ESR1) was the anti-tumor target of ellagic acid and was positively regulated by it. Inhibition of ESR1 suppressed ellagic acid-mediated pyroptosis. ESR1 expression is downregulated in HCC patients, and patients with higher ESR1 expression have longer overall survival. Glucose-6-phosphate dehydrogenase (G6PD), a key enzyme in the pentose phosphate pathway (PPP), was a negative regulatory target of ESR1. Overexpression of G6PD partially restored the decrease in G6PD activity and mitochondrial membrane potential caused by ellagic acid, thereby inhibiting pyroptosis. In conclusion, our findings suggested that ellagic acid exerts its antitumor effects in HCC by upregulating ESR1 and promoting its nuclear translocation. ESR1 then transcriptionally repressed G6PD, disrupting the pentose phosphate pathway, which led to impaired DNA synthesis, reduced nicotinamide adenine dinucleotide phosphate (NADPH) production, limited tumor growth, and the induction of pyroptosis in HCC cells.