BCR-ABL expression activates SIRT1 in human hematopoietic progenitor cells. (A) SIRT1 protein in CD34⁺ normal and CML cells. Chronic phase (CP) and advanced-phase CML (AP, accelerated phase; BC, blast crisis) were from unrelated patients with active disease. Normal CD34⁺ cells (NM) were from the peripheral blood of healthy adult donors after BM mobilization by GM-CSF treatment. Three CP patients had not received prior treatment. AP and BC patients received IFN, hydroxyurea, or combination treatment and samples were obtained after at least 2 weeks off chemotherapy, with the exception that BC patient 9 had not received prior treatment. Densitometry of SIRT1 expression was quantified after normalizing to GAPDH. Diamonds indicate no significant reading above background. (B-C) SIRT1 protein (B) and mRNA (C) levels after BCR-ABL transduction (MIG210) in normal CD34⁺ cells from 2 independent healthy donors compared with transduction of WI38 cells. Empty vector MIGR1 was used as a control. (D) Change of SIRT1 protein levels on imatinib (IM) treatment for 48 hours in the CML cell lines KCL-22, K562, and KCL-22M, and in prostate cancer PC3 cells. (E) SIRT1 expression on BCR-ABL knockdown by shABL lentiviral vector at 3-6 days after initial transduction. SCR indicates scrambled shRNA. (F) Representative Western blot analysis of FOXO1 acetylation change in CD34⁺ cells after MIG210 transduction. (G) Representative Western blot analysis of p53 acetylation. CD34⁺ cells were treated with 10μM nutlin-3 and 0.5μM trichostatin A for 6 hours, followed by p210 transduction.