Preditox : genetic assays for safety use

DNA protection

Updated : 05/25/2018

Study of the protective effect of the DNA of a compound

The genome of cells can be damaged by different types of DNA damage, whether endogenous or exogenous. If these damages are left as they are, the consequences can be important for the cell and can lead to a process of carcinogenesis. Many DNA damage response mechanisms have been developed by the cell to specifically repair each type of lesion. In addition, when the lesion is not repaired before the arrival of the DNA replication fork, a damage tolerance path exists to prevent an inadvertent stop of replication. Thus, DNA repair includes all the ways to restore the integrity of genetic information.

The study of the phosphorylation of histone H2AX (γH2AX) makes it possible to detect compounds that induce various types of DNA damage and thus permits to study following damage.

Principle

For this study, we work from the HepG2 human hepatic cell line. This is cultured for 24 hours in the presence of 6 different model compounds inducing different types of damage to DNA, such as benz[a]pyrene (DNA adduct), methyl methanesulfonate (DNA alkylation), nocodazole (aneugen), etoposide (topoisomerase II inhibitor, hydroxyurea (dNTPSs pool imbalance) and hydrogen peroxide (oxidative stress). The test compound is added in parallel to the treated cells. The differential (with or without the sample) for the quantification of the phosphorylation of histone H2AX following DNA damage permits to determine the protective effect of the DNA of a compound.