Arsenic is a well-known poison and carcinogen in humans. However, it also has been used to effectively treat some human cancers and non-carcinogenic ailments. Previously, we demonstrated in keratinocytes that arsenic trioxide (ATO)-induced p21WAF1/CIP1 (p21) expression leading to cellular cytotoxicity through the c-Src/EGFR/ ERK pathway and generation of reactive oxygen species (ROS). In this study, we found that EGFR-Y845 and EGFR-Y1173 could be phosphorylated by ATO. Using confocal microscopy and flow cytometry, we found that pretreatment with apocynin, DPI, and tiron could remove ATO-induced ROS production. Furthermore, to increase NADPH oxidase activity, ATO could induce cytosolic p67phox expression and translocation to membrane. In addition, knockdown of p67phox could abolish ATOinduced ROS production. Therefore, we suggest that NADPH oxidase-produced superoxide was a major source of ATO-induced ROS production. Conversely, ATOinduced NADPH oxidase activation and superoxide generation could be inhibited by the c-Src inhibitor PP1, but not by the EGFR inhibitor PD153035. In addition, overexpression of c-Src as well as treatment with ATO could stimulate EGFR-Y845/ERK phosphorylation, p21 expression, and cellular arrest/apoptosis, which could be attenuated by pretreatment with apocynin or knockdown of p67phox. Collectively, we suggest that NADPH oxidase was involved in the ATO-induced arrest/apoptosis of keratinocytes, which was regulated by c-Src activation.
All Science Journal Classification (ASJC) codes
- Health, Toxicology and Mutagenesis