Figure 1.

SC99 inhibits STAT3 activation in human platelets. (A) Platelets (250 μL, 3×10⁸/mL) were stimulated with collagen or thrombin at indicated concentrations for 5 min at 37 °C, and the reaction was stopped by adding RIPA buffer. After heating to 97 °C for 10 min, proteins were fractionated via 10% SDS polyacrylamide gel electrophoresis (SDS-PAGE) and analyzed using an immunoblotting assay to evaluate the STAT3 phosphorylation level. (B) Platelets were treated with collagen (2 μg/mL) or thrombin (0.02 U/mL) for the indicated periods. The platelets were then lysed and analyzed using an immunoblotting assay to evaluate the STAT3 phosphorylation level. (C) Starved platelets were pre-treated with SC99 at indicated concentrations for 10 min at 37 °C followed by stimulation with collagen (2 μg/mL) or thrombin (0.02 U/mL) for 5 min. Cell lysates from platelets were then analyzed using an immunoblotting assay to evaluate STAT3 and JAK2 phosphorylation levels. (D) Platelets were treated as described in (C) and were analyzed using an immunoblotting assay to evaluate the phosphorylation levels of p65, p-c-Src, and p-AKT using specific antibodies. β-Actin was used as an internal loading control.