Suz12 loss activates PI3K-AKT-mTOR pathway signaling. (A) Heat map of PI3K/mTOR signaling pathway genes in leukemias with Suz12 inactivation (J+S1 vs J and S1 vs WT), gene expression is shown as normalized read counts. (B) ChIP-seq tracks showing Suz12, H3K27me3, and H3K4me3 signals in S1 vs WT and J+S1 vs J conditions for the Pik3cb and Akt3 promoter. (C-F) Quantifications of MFI with SEM of phosphorylation (p-) levels and (total) protein levels of key components of the PI3K-AKT-mTOR signaling pathway: Akt (C), GSK3β (D), S6 (E), and S6K (F). P values, calculated with 2-tailed unpaired Student t test, denote significant differences between J+S1 and J cells. All MFI measurements were in APC, except total GSK3β was in PE. (G-I) Flow cytometry plots and quantifications of MFI with SEM of phosphorylation levels of Akt (G), S6 (H), and S6K (I) in J+S1 leukemia cells treated for 3 hours with 1 μM dactolisib (DAC). P values, calculated with 2-tailed unpaired Student t test, denote significant differences between DMSO and DAC. (J) Survival curve showing disease-specific survival (DSS) of J+S1 leukemia mice treated with DAC. The P value was calculated with Gehan-Breslow-Wilcoxon test. (K) WBC counts of J+S1 mice after 5 days of treatment. The P value, calculated with a 2-tailed unpaired Student t test, denotes a significant difference between DAC and placebo. (L) Weights of spleen and thymus of J+S1 leukemic mice at time of sacrifice. P values, calculated with 2-tailed unpaired Student t test, denote significant differences between placebo and DAC.