Akt inhibition induces FLNA cleavage and a decrease in rRNA synthesis and cell proliferation in AML cells. (A) Effects of AZD8055 on p-Akt expression and FLNA cleavage in primary AML cells. Ten AML patient samples were treated with AZD8055 (20 nM) or vehicle for 3 hours, and 30 μg lysate of protein was used for western blot and immunoblotted with the indicated antibodies. (B and C) Effects of AZD8055 on Pol I binding to rDNA, pre-rRNA synthesis, and cell survival in AML primary cells. Six AML samples were treated as in panel A. (B) ChIP assay was performed with anti-Pol I antibody. (C) The 5′ETS pre-rRNA was measured by qPCR (top); RNA was labeled with ³²P (bottom). Values for qPCR represent the mean ± SD of triplicate determinations. (D) Schematic model of the regulation of rRNA synthesis by activated Akt as mediated through both the inhibition of FLNA cleavage and TIF-90 activity.