Fig. 4.
NADPH oxidase is the main source of arsenic-induced ROS. (A) p47PHOX protein was induced by arsenic in cells transfected with scrambled (Scram.) siRNA, but this induction is diminished in cells transfected with p47PHOX siRNA (Inset). The lucigenin chemiluminescence induced by arsenic in p47PHOX siRNA-transfected cells was significantly diminished compared with those transfected with scrambled siRNA. As, arsenic. (B) Lucigenin chemiluminescence was absent in X-CGD cells before and after arsenic treatment. In contrast, the baseline chemiluminescence of the parental cells, PLB-985, was enhanced by arsenic treatment. (C) Cytochrome c reduction assay showed PMA-enhanced superoxide production in arsenic-treated parental cells PLB-985 but not in X-CGD cells. (D) mRNAs of most NADPH oxidase subunits in PLB-985 or X-CGD cells were increased by arsenic, as determined by real-time PCR.