3-Aminodibenzofuran (3-ADBF) is a potent bladder carcinogen. This study aimed to identify reactive metabolites and the metabolic pathways of 3-ADBF. The in vitro and in vivo studies demonstrated that 3-ADBF was oxidized to the corresponding hydroxylamine by cytochrome P450 enzymes, followed by sulfation of the hydroxyl group mediated by sulfotransferases. The resulting sulfate conjugate was chemically reactive to GSH and cysteine residues of hepatic protein to form the corresponding GSH conjugate and protein adduction. Exposure of 3-ADBF to primary hepatocytes caused protein covalent binding and decreased cell viability. The resultant protein adduction was found to correlate the observed cytotoxicity of 3-ADBF.

Nepeta cataria L. has long been used in folk food and medicine for several functions. Essential oils (EOs) were extracted from Nepeta cataria L. by supercritical fluid extraction. The results of animal experiments showed that EOs from Nepeta cataria L. significantly attenuated acetaminophen-induced liver damage. Further study confirmed that EOs were able to increase mRNA expression of uridine diphosphate glucuronosyltransferases (UGTs) and sulfotransferases (SULTs), as well as inhibit CYP2E1 activities, and thereby suppressed toxic intermediate formation. Nrf-2 activation might be involved in EOs-induced up-regulation of Phase II enzymes. Collectively, our data provide evidence that EOs protect the liver against acetaminophen-induced liver injury mainly by accelerating acetaminophen harmless metabolism, implying that EOs can be considered as a potential natural resource to develop hepatoprotective agent.

Heparan sulfate (HS) proteoglycans bind extracellular proteins that participate in cell signaling, attachment and endocytosis. These interactions depend on the arrangement of sulfated sugars in the HS chains generated by well-characterized biosynthetic enzymes; however, the regulation of these enzymes is largely unknown. We conducted genome-wide CRISPR-Cas9 screens with a small-molecule ligand that binds to HS. Screening of A375 melanoma cells uncovered additional genes and pathways impacting HS formation. The top hit was the epigenetic factor KDM2B, a histone demethylase. KDM2B inactivation suppressed multiple HS sulfotransferases and upregulated the sulfatase SULF1. These changes differentially affected the interaction of HS-binding proteins. KDM2B-deficient cells displayed decreased growth rates, which was rescued by SULF1 inactivation. In addition, KDM2B deficiency altered the expression of many extracellular matrix genes. Thus, KDM2B controls proliferation of A375 cells through the regulation of HS structure and serves as a master regulator of the extracellular matrix.