Ferroptosis has recently emerged as an iron-dependent form of nonapoptotic cell death, which is also a regulated necrosis process and a response to tumor suppression. However, whether ferroptosis is involved in ulcerative colitis (UC) is unknown. The aims of this study were to investigate whether the ferroptosis is involved in UC, particularly intestinal epithelial cell (IEC) death, and to analyze the effect of the nuclear factor kappa Bp65 subunit (NF-κBp65) on ferroptosis. The gene expression of ferroptosis-related proteins was assessed in intestinal mucosal samples from human UC. The experimental model of UC was induced with dextran sulfate sodium (DSS). Ferroptosis of IECs was evaluated, the effect of NF-κBp65 on ferroptosis was analyzed by using IEC-specific NF-κBp65-deleted mice (p65^IEC-KO), and the ferroptosis signaling pathway was investigated in vitro and in vivo. The results showed that ferroptosis was significantly induced in the IECs from UC patients and mice with colitis, and the ferroptosis was mediated by endoplasmic reticulum (ER) stress signaling. The specific deletion of IEC NF-κBp65 clearly upregulated ferroptosis and exacerbated colitis, and the result showed that phosphorylated-NF-κBp65 significantly inhibited ER stress signaling by directly binding eukaryotic initiation factor 2α. These data indicate that ferroptosis contributes to UC via ER stress-mediated IEC cell death, and that NF-κBp65 phosphorylation suppresses ER stress-mediated IEC ferroptosis to alleviate UC. The results suggest that ferroptosis involves in IEC death in UC, NF-κBp65 play a critical role in the ferroptotic inhibition, and ferroptosis is a potential therapeutic target for UC.

Nonalcoholic fatty liver disease (NAFLD)–induced hepatocellular carcinoma (HCC) is an emerging malignancy in the developed world; however, mechanisms that contribute to its formation are largely unknown, and targeted therapy is currently not available. Our RNA sequencing analysis of NAFLD-HCC samples revealed squalene epoxidase (SQLE) as the top outlier metabolic gene overexpressed in NAFLD-HCC patients. Hepatocyte-specific Sqle transgenic expression in mice accelerated the development of high-fat, high-cholesterol diet–induced HCC. SQLE exerts its oncogenic effect via its metabolites, cholesteryl ester and nicotinamide adenine dinucleotide phosphate (NADP⁺). Increased SQLE expression promotes the biosynthesis of cholesteryl ester, which induces NAFLD-HCC cell growth. SQLE increased the NADP⁺/NADPH (reduced form of NADP⁺) ratio, which triggered a cascade of events involving oxidative stress–induced DNA methyltransferase 3A (DNMT3A) expression, DNMT3A-mediated epigenetic silencing of PTEN, and activation of AKT-mTOR (mammalian target of rapamycin). In human NAFLD-HCC and HCC, SQLE is overexpressed and its expression is associated with poor patient outcomes. Terbinafine, a U.S. Food and Drug Administration–approved antifungal drug targeting SQLE, markedly inhibited SQLE-induced NAFLD-HCC cell growth in NAFLD-HCC and HCC cells and attenuated tumor development in xenograft models and in Sqle transgenic mice. Suppression of tumor growth by terbinafine is associated with decreased cholesteryl ester concentrations, restoration of PTEN expression, and inhibition of AKT-mTOR, consistent with blockade of SQLE function. Collectively, we established SQLE as an oncogene in NAFLD-HCC and propose that repurposing SQLE inhibitors may be a promising approach for the prevention and treatment of NAFLD-HCC.

Salivary HOTAIR and PVT1 as novel biomarkers for early pancreatic cancer Salivary HOTAIR and PVT1 as novel biomarkers for early pancreatic cancer

Berberine (BBR) has been explored as a potential anti-liver fibrosis agent, but the underlying mechanisms are unknown. In the current study, we aimed to investigate the molecular mechanisms underlying the effect of BBR against liver fibrogenesis in thioacetamide (TAA) and carbon tetrachloride (CCl₄) induced mouse liver fibrosis. In addition to i.p. injection with TAA or CCl₄, mice in the treatment group received BBR intragastrically. Concurrently, combined with TAA and BBR treatment, mice in the inhibitor group were injected i.p. with ferrostatin-1 (Fer-1). Hepatic stellate cells (HSCs) were also used in the study. Our results showed that BBR obviously alleviated mouse liver fibrosis and restored mouse liver function; however, the pharmacological effects of BBR against liver fibrosis were significantly diminished by Fer-1 treatment. Mechanically, BBR impaired the autophagy–lysosome pathway (ALP) and increased cell reactive oxygen species (ROS) production in HSCs. ROS accelerated the breakdown of the iron-storage protein ferritin and sped up iron release from ferritin, which resulted in redox-active iron accumulation in HSCs. Lipid peroxidation and glutathione (GSH) depletion triggered by the Fenton reaction promoted ferroptosis and attenuated liver fibrosis. Furthermore, impaired autophagy enhanced BBR-mediated ferritin proteolysis to increase cellular ferrous overload via the ubiquitin–proteasome pathway (UPS) in HSCs and triggered HSC ferroptosis. Collectively, BBR alleviated liver fibrosis by inducing ferrous redox to activate ROS-mediated HSC ferroptosis. Our findings may be exploited clinically to provide a potential novel therapeutic strategy for liver fibrosis.

The transcription factor nuclear factor-κB (NF-κB) mediates inflammation and stress signals in cells. To test NF-κB in the control of hepatic insulin sensitivity, we inactivated NF-κB in the livers of C57BL/6 mice through deletion of the p65 gene, which was achieved by crossing floxed-p65 and Alb-cre mice to generate L-p65-knockout (KO) mice. KO mice did not exhibit any alterations in growth, reproduction, and body weight while on a chow diet. However, the mice on a high-fat diet (HFD) exhibited an improvement in systemic insulin sensitivity. Hepatic insulin sensitivity was enhanced as indicated by increased pyruvate tolerance, Akt phosphorylation, and decreased gene expression in hepatic gluconeogenesis. In the liver, a decrease in intracellular cAMP was observed with decreased CREB phosphorylation. Cyclic nucleotide phosphodiesterase-3B (PDE3B), a cAMP-degrading enzyme, was increased in mRNA and protein as a result of the absence of NF-κB activity. NF-κB was found to inhibit PDE3B transcription through three DNA-binding sites in the gene promoter in response to tumor necrosis factor-α. Body composition, food intake, energy expenditure, and systemic and hepatic inflammation were not significantly altered in KO mice on HFD. These data suggest that NF-κB inhibits hepatic insulin sensitivity by upregulating cAMP through suppression of PDE3B gene transcription.