Inhibition of STAT3 in glioma cells elicits cell death. Glioma cells were cultured with STAT3 inhibitor at the dose indicated for a period of 48 hours in triplicate wells. Cells were analyzed by flow cytometry following staining with annexin V and PI. (A) Representative dot plots from flow cytometric analysis of mouse (Gl26, SMA560), rat (CNS-1), and human (U251, IN859, HF2303) glioma cell lines treated with annexin V and PI presented on the x- and y-axis, respectively. (B) Cells deemed to be apoptotic (annexin V+ or annexin V+/PI+) were quantified and presented in bar graphs. Inhibition by STAT3 small molecule inhibitors elicits significant levels of cell death (*P < 0.05 versus vehicle; one-way ANOVA followed by Tukey-Kramer multiple-comparison test).