Zebularine upregulates expression of CYP genes through inhibition of DNMT1 and PKR in HepG2 cells

• Published in: Scientific reports Vol. 7; no. 1; p. 41093
• Main Authors: Nakamura, Kazuaki, Aizawa, Kazuko, Aung, Kyaw Htet, Yamauchi, Junji, Tanoue, Akito
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 23-01-2017; Nature Publishing Group
• Subjects: 13; 13/106; 631/154/436/1729; 631/154/570; Apoptosis - drug effects; Cell lines; Cyclophilins - genetics; CYP gene; Cytidine - analogs & derivatives; Cytidine - pharmacology; Deoxyribonucleic acid; DNA; DNA (Cytosine-5-)-Methyltransferase 1 - genetics; DNA methylation; DNA Methylation - drug effects; DNA methyltransferase; DNMT1 protein; Double-stranded RNA; Drug development; eIF-2 kinase; eIF-2 Kinase - genetics; Gene expression; Gene Expression Regulation, Neoplastic - drug effects; Hep G2 Cells; Hepatocytes; Hepatocytes - drug effects; Hepatotoxicity; Humanities and Social Sciences; Humans; Kinases; multidisciplinary; Protein kinase; Science; Science (multidisciplinary); Toxicity
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/srep41093

Drug-induced hepatotoxicity is one of the major reasons cited for drug withdrawal. Therefore, it is of extreme importance to detect human hepatotoxic candidates as early as possible during the drug development process. In this study, we aimed to enhance hepatocyte functions such as CYP gene expression in HepG2 cells, one of the most extensively used cell lines in evaluating hepatotoxicity of chemicals and drugs. We found that zebularine, a potent inhibitor of DNA methylation, remarkably upregulates the expression of CYP genes in HepG2 cells. In addition, we revealed that the upregulation of CYP gene expression by zebularine was mediated through the inhibition of both DNA methyltransferase 1 (DNMT1) and double-stranded RNA-dependent protein kinase (PKR). Furthermore, HepG2 cells treated with zebularine were more sensitive than control cells to drug toxicity. Taken together, our results show that zebularine may make HepG2 cells high-functioning and thus could be useful for evaluating the hepatotoxicity of chemicals and drugs speedily and accurately in
in-vitro
systems. The finding that zebularine upregulates CYP gene expression through DNMT1 and PKR modulation sheds light on the mechanisms controlling hepatocyte function and thus may aid in the development of new
in-vitro
systems using high-functioning hepatocytes.