FIGURE 1.

AZD8055 treatment attenuates 5-FU-induced cell death in human colon cancer cell lines. A, AZD8055 (1 μm) attenuates cell death induced by 5-FU (6 μm: HT-29; 100 μm: DLD1). Cells were incubated with study drugs for 3 days and annexin V/PI labeling was performed. Apoptosis is indicated by annexin V⁺ PI⁻-labeled cells and late apoptosis/necrosis is shown by annexin V⁺PI⁺ cells. Columns, mean of experiments conducted in triplicate; bars, S.D. B and C, AZD8055 attenuates caspase-9 and -3 cleavage (B) and DNA damage (C) induced by 5-FU (5 days) or CPT-11 (3 days) in HT-29 and/or DLD1 cells. DNA damage was measured by expression of p-H2AX that detects DNA double-stranded breaks. Tubulin served as a control for protein loading. D, suppression of colony formation by 5-FU is reduced by co-treatment with AZD8055 in both cell lines. Cells were incubated with drugs for 3 days and equal numbers of cells were replated and grown for 14 days in drug-free media. Colonies were visualized by staining with crystal violet.