PKCϵ overexpression or down-modulation. (A) Western blot of PKCϵ in TF-1 cells overexpressing PKCϵ (PKCϵ) or mutated PKCϵ (PKCϵm). Exogenous PKCϵ (PKCϵ-GFP) and endogenous PKCϵ (PKCϵ) proteins are shown in the immunoblot. (B) Cell viability of TF-1 cells overexpressing PKCϵ or PKCϵm. After 24 hours, the cells were treated with or without 5 nM PDBu in the presence or absence of 25 ng/mL TRAIL for 3 days. Data from 3 experiments are expressed as means plus or minus SD. *P < .05 versus control; #P < .05 TRAIL plus PDBu versus PDBu alone. (C) PKCϵ overexpression reduces the density of surface MK markers in TF-1 cells. TF-1 cells were transfected with PKCϵ (black histograms, PKCϵ) or mutated PKCϵ (gray histograms, PKCϵm). After 24 hours, the cells were cultured with or without 5 nM PDBu and analyzed 3 days later. Data from 3 experiments are expressed as means plus or minus SD of absolute numbers of surface antigens (MESF) expressed per cell. *P < .05 versus control; #P < .05 PKCϵ versus PKCϵm. (D) Western blot of PKCϵ in primary AML cells transfected with PKCϵ-specific siRNA (PKCϵ siRNA) or control siRNA (Scrambled siRNA). (E) Cell viability of primary AML cells transfected with PKCϵ-siRNA or control siRNA (Scrambled siRNA). After 48 hours, the cells were treated with or without 20 nM PDBu in the presence of 500 ng/mL TRAIL for 3 days. Data from 3 experiments are expressed as means plus or minus SD. *P < .05 versus control; #P < .05 PKCϵ siRNA versus Scrambled siRNA. (F) PKCϵ down-regulation induces the expression of CD41 MK marker in primary AML cells while reducing the density of surface CD33. AML cells were transfected with PKCϵ siRNA or control siRNA (Scrambled siRNA). After 48 hours, the cells were cultured with or without 20 nM PDBu in the presence of 500 ng/mL TRAIL and analyzed 3 days later. Data from 3 experiments are expressed as means plus or minus SD of absolute numbers of surface antigens (MESF) expressed per cell. *P < .05; #P < .05 PKCϵ siRNA versus Scrambled siRNA.