Figure 1. Time- and dose-dependent As3+-induced apoptosis in Hepa-1c1c7 cells.
(A and B) Hepa-1c1c7 cells were treated for 16 h with the indicated concentrations of As3+ or with 20 uM As3+ for the time periods indicated. (A) As3+-induced apoptosis was quantified by assessing apoptotic nuclear morphology of DAPI-stained cells (Pierce et al., 2000). (B) Caspase activities were determined as described in the Methods section utilizing the fluorogenic substrates Ac-DEVD-AMC (caspase-3), AcIETD-AMC (caspase-8), and Ac-LEHD-AMC (caspase-9). (C) Cells were pretreated with z-VAD-fmk (50 uM) for 1 h prior to treatment with As3+ (20 uM) for 16 h and apoptosis quantified as described above. Data presented are averages +/- SEM of at least three experiments. + p < 0.05, * p < 0.01, # p < 0.001, indicates a significant difference compared to untreated control, and ^ p < 0.001 indicates a significant difference from As3+-only treated cells.