Figure 5. Akt activation allows sustained histone acetylation in glucose-limited conditions.

(A) Western blot analysis of proteins and histones from LN229 and LN229-myrAkt cells. Quantitation represents 5 independent experiments with LN229 4mM samples set to 1, mean +/− SEM (*, p ≤0.05). (B) Western blot analysis of histone acid extracts from LN229 cells stably expressing vector (EV), wt ACL, ACL-S455A, or ACL-S455D. Cells were treated with 1 or 10mM glucose for 24 hours before lysis. Quantitation represents the ratio of acetylated to total histones in four independent experiments with EV 10 mM set to 1, mean +/− SEM (*, p≤0.05) (C) Relative acetyl-CoA concentrations and percent enrichment after treatment in 1 mM or 10 mM [U-¹³C₆]-glucose for 20 hours, mean +/− SEM of triplicates. Total acetyl-CoA levels as well as M+2 acetyl-CoA (enriched from glucose) were significantly suppressed (p≤0.05) in 1 mM as compared to 10 mM glucose in EV and WT-ACL cells, but not ACL-S455D cells. (D) Control (MTB) and transgenic (MTB-tAkt) mice were administered doxycyclin for 96 hours (n≥5, each group). Immunohistochemistry was performed on paraffin-embedded mammary tissue sections. Representative images are shown, along with magnification of areas of interest. Scale bar: 50 μm.