Figure 2: Effect of ATO on morphological and apoptotic-related changes in A549 lung cancer cells. The cells were stained with DAPI and visualized on an Olympus Epifluorescence microscope 20X. A549 cells were treated for 48 hr with ATO at 0 (control), 2, 4 and 6 µg/ml respectively. Panel A (0 µg/ml), the arrow points to a nucleus fluorescing bright blue; Panel B (2 µg/ml), the black arrow indicates viable cells and the white arrow represents a non-viable cell; Panel C (4 µg/ml), the arrows indicate apoptotic nuclei with condensed chromatin; and Panel D (6 µg/ml), the arrow is pointing to apoptotic bodies within the nucleus.