SIRT1 protein expression is regulated by FLT3-ITD tyrosine kinase activity. (A-B) Molm-14 and MV4-11 cells were treated with 100 nM PKC412 for different periods (A) and different concentrations for 24 hours (B), as indicated. SIRT1 expression, p53 acetylation, and tyrosine phosphorylation of FLT3 and STAT5 were analyzed by immunoblotting. (C) Molm-14, MV4-11, and HL-60 cells were transduced with lentiviral vectors expressing nonsilencing scrambled shRNA or with 2 different FLT3 shRNA clones. Forty-eight hours after transduction, SIRT1 expression, p53 acetylation, FLT3 tyrosine phosphorylation, and expression were analyzed. (D) MV4-11 cells were transduced with lentiviral vectors expressing a doxycycline-inducible nonsilencing miR-shRNA (shScr) or a miR-shRNA targeting KRAS (sh_KRAS; left), STAT5 (sh_STAT5-1 and sh_STAT5-2; middle), or lentiviral vectors expressing 2 different AKT1 shRNA clones (right). Immunoblot analysis was performed 72 hours after doxycycline treatment or straight knockdown, respectively.