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 () as the top outlier metabolic gene overexpressed in NAFLD-HCC patients. Hepatocyte-specific transgenic expression in mice accelerated the development of high-fat, high-cholesterol diet-induced HCC. exerts its oncogenic effect via its metabolites, cholesteryl ester and nicotinamide adenine dinucleotide phosphate (NADP). Increased expression promotes the biosynthesis of cholesteryl ester, which induces NAFLD-HCC cell growth. 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, is overexpressed and its expression is associated with poor patient outcomes. Terbinafine, a U.S. Food and Drug Administration-approved antifungal drug targeting, markedly inhibited -induced NAFLD-HCC cell growth in NAFLD-HCC and HCC cells and attenuated tumor development in xenograft models and in 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 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.

A safe, potent and broad-spectrum antiviral is urgently needed to combat emerging respiratory viruses. In light of the broad antiviral activity of β-defensins, we tested the antiviral activity of 11 peptides derived from mouse β-defensin-4 and found that a short peptide, P9, exhibited potent and broad-spectrum antiviral effects against multiple respiratory viruses in vitro and in vivo, including influenza A virus H1N1, H3N2, H5N1, H7N7, H7N9, SARS-CoV and MERS-CoV. The antiviral activity of P9 was attributed to its high-affinity binding to viral glycoproteins, as well as the abundance of basic amino acids in its composition. After binding viral particles through viral surface glycoproteins, P9 entered into cells together with the viruses via endocytosis and prevented endosomal acidification, which blocked membrane fusion and subsequent viral RNA release. This study has paved the avenue for developing new prophylactic and therapeutic agents with broad-spectrum antiviral activities.

BACKGROUND & AIMS: Mutant KRAS promotes glutaminolysis, a process that uses steps from the tricarboxylic cycle to convert glutamine to a-ketoglutarate and other molecules via glutaminase and SLC25A22. This results in inhibition of demethylases and epigenetic alterations in cells that increase proliferation and stem cell features. We investigated whether mutant KRAS-mediated glutaminolysis affects the epigenomes and activities of colorectal cancer (CRC) cells. METHODS: We created Apc min Kras G12D mice with intestine-specific knockout of SLC25A22 (Apc min Kras G12D SLC25A22 fl/fl mice). Intestine tissues were collected and analyzed by histology, immunohistochemistry, and DNA methylation assays; organoids were derived and studied for stem cell features, along with organoids derived from 2 human colorectal tumor specimens. Colon epithelial cells (1CT) and CRC cells (DLD1, DKS8, HKE3, and HCT116) that expressed mutant KRAS, with or without knockdown of SLC25A22 or other proteins, were deprived of glutamine or glucose and assayed for proliferation, colony formation, glucose or glutamine consumption, and apoptosis; gene expression patterns were analyzed by RNA sequencing, proteins by immunoblots, and metabolites by liquid chromatography-mass spectrometry, with [U-13 C 5 ]-glutamine as a tracer. Cells and organoids with knocked down, knocked out, or overexpressed proteins were analyzed for DNA methylation at CpG sites using arrays. We performed immunohistochemical analyses of colorectal tumor samples from 130 patients in Hong Kong (57 with KRAS mutations) and Kaplan-Meier analyses of survival. We analyzed gene expression levels of colorectal tumor samples in The Cancer Genome Atlas. RESULTS: CRC cells that express activated KRAS required glutamine for survival, and rapidly incorporated it into the tricarboxylic cycle (glutaminolysis); this process required SLC25A22. Cells incubated with succinate could proliferate under glutamine-free conditions. Mutant KRAS cells maintained a low ratio of a-ketoglutarate to succinate, resulting in reduced 5-hydroxymethylcytosine-a marker of DNA demethylation, and hypermethylation at CpG sites. Many of the hypermethylated genes were in the WNT signaling pathway and at the protocadherin gene cluster on chromosome 5q31. CRC cells without mutant KRAS, or with mutant KRAS and knockout of SLC25A22, expressed protocadherin genes