Reduction of PHLPP1 and PHLPP2 expression on ALDHhi hematopoietic progenitor cells derived from CML patients. A, ALDHhi cells were transfected with PHLPP1 siRNA and/or PHLPP2 siRNA and then treated with STI571 (10 μm) for 14–17 days. The numbers of CFU-GEMM, CFU-GM, and BFU-E were counted. The rate of the progenitor cells was evaluated as a percentage of the corresponding control. Each bar represents the mean of S.D. of three independent experiments. B and C, the relative expression levels of PHLPP1 and PHLPP2 mRNA of CFU-GEMM, CFU-GM, and BFU-E derived from PHLPP1 and/or PHLPP2 siRNA-transfected ALDHhi cells were assessed after 14–17 days of treatment with STI571 (10 μm). For the analysis of PHLPP1 and PHLPP2 expression, quantitative RT-PCR was performed relative to the G3PDH gene. Data are shown as mean ± S.D. in triplicate culture and are representative of three independent experiments (upper panels). Fourteen days after treatment with STI571 in ALDHhi cells transfected with PHLPP1 and/or PHLPP2 siRNA, the cells from CFU-GEMM, CFU-GM, and BFU-E were harvested. To detect PHLPP1 and PHLPP2, RT-PCR was performed. G3PDH is shown as an internal control. The RT-PCR results are representative of three independent experiments (bottom panels).