SIRT1 Inhibition-Induced Mitochondrial Damage Promotes GSDME-Dependent Pyroptosis in Hepatocellular Carcinoma Cells

Abstract

Hepatocellular carcinoma (HCC) is a malignant tumor that affects the liver and poses a significant threat to human health. Further investigation is necessary to fully understand the role of SIRT1, a protein linked to tumorigenesis, in HCC development. To investigate the effect of SIRT1 on HCC and elucidate the underlying mechanism. Eight pairs of HCC and paracancerous normal tissue specimens were collected. The levels of SIRT1 and GSDME in tissue samples were assessed using immunohistochemistry and western blotting. SIRT1 levels were determined in HCC (Huh7, HepG2, SNU-423, SNU-398, and HCCLM3) and L-02 cells using reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blotting. SNU-423 and HCCLM3 cells were transfected with si-SIRT1 and/or si-GSDME to knock down SIRT1 or GSDME expression. RT-qPCR and western blotting were performed to measure the expression of SIRT1, pro-casp-3, cl-casp-3, GSDME, GSDME-N, PGC-1α, Bax, and cytochrome c (Cyto C). Cell proliferation, migration, invasion, and apoptosis were assessed using the cell counting kit-8 (CCK-8), wound healing assay, Transwell invasion assay, and flow cytometry, respectively. The release of lactate dehydrogenase (LDH) was evaluated using an LDH kit. SIRT1 was upregulated in HCC tissues and cells, and a negative correlation was observed between SIRT1 and GSDME-N. SIRT1 silencing suppressed the proliferation, migration, and invasion of HCC cells while also promoting apoptosis and inducing mitochondrial damage. Additionally, the silencing of SIRT1 resulted in the formation of large bubbles on the plasma membrane of HCC cells, leading to cellular swelling and aggravated GSDME-dependent pyroptosis, resulting in an increase in LDH release. Inhibition of GSDME reduced SIRT1 silencing-induced cell swelling, decreased LDH release rate, and promoted apoptosis. SIRT1 silencing promotes GSDME-dependent pyroptosis in HCC cells by damaging mitochondria.