Fig. 2. DPI and iodonium analogs inhibit HT-29 cell proliferation and colony formation in a concentration- and time-dependent manner.

(A) HT-29 cells were treated for 72 h with concentrations of the iodonium analogs ranging from 0 to 1000 nM, or (B) with 100 nM iodonium analogs for the indicated times, or (C) with 500 nM iodonium analogs for different time intervals ranging from 8 to 72 h. Cell viability was assessed with the MTT assay. The inhibition of the colony-forming abilities of HT-29 cells was also assessed after iodonium analog treatment. (D, E) HT-29 cells were treated with DPI (D), or 392 (E) at 0, 8, 40, 200, 500, and 1000 nM for 6 h. (F, G) HT-29 cells treated with compound 104 (F), or compound 428 (G) for 2 h, 6 h, or 10 days. All data represent the mean ± SD of at least three experiments. (H) HT-29 cells were treated for 96 h with 0–2000 U/ml SOD (black bars), 0–2000 U/ml catalase (dark grey bars), or the combination of SOD and catalase at 0–2000 U/ml (light grey bars). SOD, catalase, or the combination had significantly decreased proliferation compared to control-treated cells (for catalase alone or in combination with SOD at concentrations ≥ 500 U/ml: ***P< 0.001, df=4; for SOD alone: **P< 0.01, df=4 at 500 U/ml SOD; **P< 0.01, df=3 at 1000 U/ml SOD; ***P< 0.001, df=4 at SOD concentrations ≥1500 U/ml SOD).