Mitochondrial GCN5L1 acts as a novel regulator for iron homeostasis to promote sorafenib sensitivity in hepatocellular carcinoma.

BACKGROUND: Sorafenib resistance is becoming increasingly common and disadvantageous for hepatocellular carcinoma (HCC) treatment. Ferroptosis is an iron dependent programmed cell death underlying the mechanism of sorafenib. Iron is crucial for synthesis of cofactors essential to mitochondrial enzymes and necessary for HCC proliferation, while mitochondrial iron overload and oxidative stress are associated with sorafenib induced ferroptosis. However, the crosstalk among iron homeostasis and sorafenib resistance is unclear. METHODS: We conducted bioinformatics analysis of sorafenib treated HCC datasets to analyze GCN5L1 and iron related gene expression with sorafenib resistance. GCN5L1 deleted HCC cell lines were generated by CRISPR technology. Sorafenib resistant HCC cell line was established to validate dataset analysis and evaluate the effect of potential target. RESULTS: We identified GCN5L1, a regulator of mitochondrial acetylation, as a modulator in sorafenib-induced ferroptosis via affecting mitochondrial iron homeostasis. GCN5L1 deficiency significantly increased sorafenib sensitivity in HCC cells by down-regulating mitochondrial iron transporters CISD1 expression to induce iron accumulation. Mitochondrial iron accumulation leads to an acceleration in cellular and lipid ROS. Sorafenib resistance is related to CISD1 overexpression to release mitochondrial iron and maintaining mitochondrial homeostasis. We combined CISD1 inhibitor NL-1 with sorafenib, which significantly enhanced sorafenib-induced ferroptosis by promoting mitochondrial iron accumulation and lipid peroxidation. The combination of NL-1 with sorafenib enhanced sorafenib efficacy in vitro and in vivo. CONCLUSIONS: Our findings demonstrate that GCN5L1/CISD1 axis is crucial for sorafenib resistance and would be a potential therapeutic strategy for sorafenib resistant HCC.

Loss of GCN5L1 exacerbates damage in alcoholic liver disease through ferroptosis activation.

BACKGROUND AND AIMS: Iron overload, oxidative stress and ferroptosis are associated with liver injury in alcohol-associated liver disease (ALD), however, the crosstalk among these regulatory pathways in ALD development is unclear. METHODS: ALD mouse model and general control of amino acid synthesis 5 like 1 (GCN5L1) liver knockout mice were generated to investigate the role of GCN5L1 in ALD development. Proteomic screening tests were performed to identify the key factors mediating GCN5L1 loss-induced ALD. RESULTS: Gene Expression Omnibus data set analysis indicates that GCN5L1 expression is negatively associated with ALD progression. GCN5L1 hepatic knockout mice develop severe liver injury and lipid accumulation when fed an alcohol diet. Screening tests identified that GCN5L1 targeted the mitochondrial iron transporter CISD1 to regulate mitochondrial iron homeostasis in ethanol-induced ferroptosis. GCN5L1-modulated CISD1 acetylation and activity were crucial for iron accumulation and ferroptosis in response to alcohol exposure. CONCLUSION: Pharmaceutical modulation of CISD1 activity is critical for cellular iron homeostasis and ethanol-induced ferroptosis. The GCN5L1/CISD1 axis is crucial for oxidative stress and ethanol-induced ferroptosis in ALD and is a promising avenue for novel therapeutic strategies.