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. Author manuscript; available in PMC: 2010 Oct 1.
Published in final edited form as: Stem Cells. 2009 Oct;27(10):2393–2404. doi: 10.1002/stem.188

Figure 5.

Figure 5

STAT3 is a downstream mediator of IL6 in GSCs and mediates GSC survival. (A) STAT3 phosphorylation is decreased with IL6 or IL6Rα knockdown. 48 hours after T3691 and T3359 GSCs were infected with IL6 or IL6Rα shRNA expressing lentivirus, levels of phosphorylated STAT3 (at Tyr 705) and total Stat3 were reduced when examined by Western. Image J software was used to quantify the relative levels of phosphorylated STAT3 to total STAT3. (B) STAT3 inhibitors decreased the phosphorylation of of Stat3 in GSCs. T3691 and T3359 GSCs treated with vehicle control or 5 μM Stattic or JSI-124 for 4 hours have reduced Stat3 phosphorylation assessed via Western. (C) STAT3 inhibitors increase the percentage of Annexin V positive cells in GSCs. T3691 and T3359 GSCs treated with 5 μM Sttattic or 5 μM JSI-124 for 24 hours demonstrated an increased percentage of apoptotic cells as measured by FACS analysis with Annexin V-FITC and PI staining compared to DMSO control. (D) STAT3 inhibitors increase caspase 3/7 activity in GSCs. T3691 and T3359 GSCs treated with 5 μM Sttattic or 5 μM JSI-124 for 24 hours demonstrated increased activity in the caspase 3/7 assay (Promega) compared with DMSO control. *, p < 0.01 with ANOVA comparison to vehicle treated control.