Figure 1.

Cell death resulting from PI3K inhibition. MC/9 cells were washed three times and resuspended in complete medium containing the indicated cytokine, or medium without cytokine (starved). LY-294002 (25 μM; closed circles) or vehicle (open circles) were added at time 0, and at the indicated hours duplicate aliquots of cells were removed, washed, stained with annexin-V-FITC and propidium iodide, and analyzed by using flow cytometry. We found that cells undergoing apoptosis quickly showed an increase in annexin-V binding but excluded propidium iodide (early apoptosis). At later time points the percentage of propidium iodide staining cells gradually increased (late apoptosis). We are reporting here the total amount of annexin-V-FITC and propidium iodide staining, which is representative of populations containing cells at both stages of apoptosis. Results are representative of at least four independent experiments.