Phosphorylation of Histone H2AX Is a Powerful Tool for Detecting Chemical Photogenotoxicity

Abstract

Several light-absorbing chemicals are known to show phototoxic effects involving many kinds of DNA damage, and are suspected of initiating skin cancer. In this study, we clarified that phosphorylated histone H2AX (γ-H2AX) (phosphorylated histone H2AX), which was produced with the induction of DNA double-strand breaks, is a sensitive photogenotoxic marker. The immortal human keratinocyte line HaCaT was treated with a library of 11 chemicals (including known strong and weak phototoxic chemicals, and nonphototoxic chemicals) and/or UVA exposure. γ-H2AX was generated after treatments with all phototoxic chemicals and UVA. The limit of detection using γ-H2AX was 100-1,000 times lower than that using cell viability and DNA gel electrophoresis. γ-H2AX was not generated following treatments with nonphototoxic chemicals and UVA. These results indicated that γ-H2AX is a powerful tool for detecting chemical photogenotoxicity.

γ-H2AX is a sensitive marker of DNA damage induced by metabolically activated 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone

“…The repair of these types of damage also induce c-H2AX (Bonner et al, 2008). In addition to c-H2AX formation after many types of DNA damage, we and other researchers are convinced that c-H2AX detection provides a considerably more sensitive and convenient measurement of DNA damage than other techniques such as pulse field gel electrophoresis and comet assays (Mah et al, 2010;Toyooka and Ibuki, 2006;Toyooka et al, 2011).…”

“…We previously reported that phosphorylation of histone H2AX (c-H2AX) is a good marker for several types of DNA damage (Toyooka and Ibuki, 2006;Toyooka et al, 2011). c-H2AX was originally identified as an early event after the direct formation of DNA double-strand breaks (DSBs) (Rogakou et al, 1998).…”

“…Immunofluorescence staining of c-H2AX was performed as described previously (Toyooka et al, 2011). NNK-treated A549 cells were fixed in 6% formaldehyde and washed in PBS containing 0.5% Triton X-100.…”

Nonylphenol polyethoxylates induce phosphorylation of histone H2AX

“…We previously reported that ␥-H2AX is generated following the exposure of cells to various suspected DNA-damaging agents including several environmental chemicals and pharmacological agents [20][21][22][23][24][25][26][27][28]. In addition to the advantage that ␥-H2AX can be detected in response to many types of DNA damage, we and other researchers are convinced that ␥-H2AX provides a considerably more sensitive measurement of DNA damage than other techniques such as pulse field gel electrophoresis and comet assays [26][27][28][29]. Therefore, focusing on ␥-H2AX as a genotoxic marker is a good way to identify the genotoxic potential of environmental pollutants.…”

Sinalização da GTPase RhoA nas respostas celulares após estresse genotóxico promovido por radiação ultravioleta.

“…Foi demonstrado a co-localização de pH2AX inclusive com outras proteínas sinalizadoras de dano de DNA, como ATM e Rad51 em focos de dano de DNA após exposição à radiação ultravioleta (Oh et al, 2011;Toyooka et al, 2011).…”