Characterization of murine isogenic normal and NRF2-KO colon epithelial cells to explore the food contaminants toxicity and oxidative stress involvement.

Abstract Cell lines are a useful tool for cellular metabolism and xenobiotic toxicity studies, but for modeling biological effects of molecules on healthy cells or cancer promotion it appeared necessary to develop a cellular model in a normal genetic context without mutations inherent to carcinogenic transformations. Colon mucosa is currently the target of xenobiotics such as food contaminants or naturally produced biomolecules from digestion, compelling normal cells to deal with toxic effects that can lead to genotoxicity and carcinogenic transformations. The toxicological properties of such compounds may rely on reactive oxygen species generation (ROS) which causes oxidative stress. One of the major regulators of ROS metabolism and antioxidant cellular defense is the transcription factor Nrf2. We developed a dual-cell model comparing normal murine epithelial cells with their Nrf2-KO isogenic cells generated through the CRISPR /Cas9 technique. HNE (4-hydroxy-2-nonenal), a lipid peroxidation product resulting from red meat digestion, inducing oxidative stress was used as a model molecule to evaluate normal epithelial cell response to food contaminant toxicity, and the importance of Nrf2 in the cellular protection against ROS injury. Implications of glutathione levels, gene regulation, viability, cell proliferation, and genotoxicity are discussed.