Cotreatment with PS and/or TG exerts greater down-regulation of JAK2 and downstream signaling, as well as greater cytotoxicity than either agent alone in primary MF-MPN cells. (A) CD34⁺ progenitor cells isolated from primary MF-MPN peripheral blood samples and normal CD34⁺ bone marrow progenitor cells were treated with the indicated concentrations of TG and/or panobinostat for 48 hours. After treatment, the percentages of nonviable cells were determined by trypan blue dye uptake in a hemocytometer. * indicates values significantly greater (P < .05) than treatment with either agent alone. (B) Primary MF-MPN cells were treated with the indicated concentrations of PS for 24 hours. Cell lysates were prepared and immunoblot analyses were performed for JAK2, pSTAT5 (Tyr694), STAT5, pSTAT3 (Tyr705), STAT3, Bcl-x_L, pAKT (Ser473), AKT, pERK1/2, ERK1/2, and acetylated K69 hsp90. The expression levels of β-actin in the lysates served as the loading control. (C) Primary MF-MPN cells were treated with the indicated concentrations of TG and/or panobinostat for 24 hours. Then, cell lysates were prepared and immunoblot analyses were performed for JAK2, pSTAT5 (Tyr694), STAT5, pSTAT3 (Tyr705), and STAT3. The expression levels of β-actin in the lysates served as the loading control. (D) Primary CD34⁺CD38⁻Lin⁻ stem cells from MF-MPN patients were treated with the indicated concentrations of TG and PS for 48 hours. After treatment, the percentages of nonviable cells were determined by trypan blue dye uptake in a hemocytometer.