Figure 5.

Eltrombopag activates all main biochemical pathways downstream of c-Mpl in in vitro differentiated megakaryocytes. (A) Lysates from megakaryocyte cultures in the presence of 10 ng/mL recombinant human thrombopoietin (rHuTPO), or 200, 500 and 2000 ng/mL eltrombopag, were obtained at day 13 of differentiation. Samples were probed for phosphorylated STAT3 (pSTAT3), phosphorylated STAT5 (pSTA5), phosphorylated AKT (pAKT) and phosphorylated ERK1/2 (pERK1/2). Total STAT3, STAT5, AKT, ERK1/2 and β-actin were revealed to ensure equal loading. (B–D) Densitometric analysis demonstrated sustained activation by eltrombopag of all signaling molecules in a dose-dependent manner, with a significant difference with respect to 10 mg/mL rHuTPO, as standard control condition (*P<0.05).