Fig. 4.

ZT55 effectively blocks JAK2/STAT3/5 signaling pathway in HEL cells. The HEL cells were treated for 24 h with the indicated concentrations of ZT55. (a) and (b) Total and phosphorylated levels of JAK1, JAK2, JAK3, STAT3, and STAT5 were determined by western blot with respective antibodies of anti-JAK1, anti-p-JAK1(y1022/1023), anti-JAK2, anti-p-JAK2(y1007/1008), anti-JAK3 and anti-p-JAK3(tyr980/981), anti-STAT3, anti-p-STAT3(tyr705), anti-STAT5, and anti-p-STAT5(tyr694). (c) and (d) The expression of SOSC1, SOSC3, Bcl2, and Bax were determined by western blot with respective antibodies of anti-SOSC1, anti-SOSC3, anti-Bcl2, and anti-Bax. (e) and (f) Caspase-3/7 and caspase-9 activity were determined by a luminescent Caspase-Glo-3/7 or Caspase-Glo-9 assays, respectively. The mean IC₅₀ results were calculated from three independent experiments