Host: The Japanese Society of Toxicology
Name : The 50th Annual Meeting of the Japanese Society of Toxicology
Date : June 19, 2023 - June 21, 2023
Genomic DNA is continuously exposed by exogenous and endogenous chemical reagents. Such chemical exposure may induce not only gene mutations and chromosomal aberrations via formation of DNA damages, but also epigenetic alterations via aberrant DNA methylation and histone modifications. Standard genotoxicity assays have been widely used to screen genotoxic reagents that potentially cause DNA damages in genomic DNA. Based on the in vitro genotoxicity test method, we developed a new assay system evaluating epigenetic alteration in the human genome. Using a human lymphoblastoid TK6 genotoxicity test cell line, “mTK6” cell line was established via DNA methylation at the promoter region of the endogenous TK gene by CRISPR/dCas9-DNMT3A system. The DNA methylation status at the TK reporter gene was bi-directionally variable, which was expected to enable to quantify the alteration of epigenetic profile. Obviously, based on the principle of TK gene mutation assay, epigenetic effects of certain reagents were quantitatively assessed by determining the number of TK revertant colonies after exposure to chemicals. Our results suggest that this method enables the evaluation of chemical-induced epigenetic effects in human cells without the use of expensive instruments. In this symposium, the usefulness of the established assay for detecting epigenetic effects and elucidating mechanisms of epi-genome maintenance will be discussed.
