Doxorubicin (Dox)-induced Apoptosis in CSCs via Increased Caspase-3 Activity.

(A) Cell viability under Dox-treatment. CSCs were treated with Dox for 48hrs at the indicated concentrations. Fluorescent microscopy images represent live cells (in green) stained with Calcein-AM. Dead floating cells were washed away during medium changes. Scale bar = 500μm. The means of viability rates (%), calculated by normalizing fluorescent intensities of Dox-treated groups to control levels, are shown in the bar graphs on the right. The % of viable cells are inversely proportional to the concentrations of Dox (n = 9; **: p(B) Caspase-3 activity under Dox-induced apoptosis. During 48hrs treatment, more dead cells (white spots) were observed and live cell density was gradually reduced as Dox concentrations increased (b1 to b6). Scale bar = 200μm. Means of Caspase-3 activities are shown in the bar graph on the right with a maximum response at 0.6μM Dox (n = 9; ns: no significance, *: p