Loss of LKB1 results in increased bioenergetic markers in ErbB2-positive mammary tumors and derived cell lines. (A-F) Six NIC/LKB+/+ and six NIC/LKB1fl/fl mammary tumors were subjected to LC-MS analysis. Intracellular levels of glucose (A), lactate (B), creatine (C), ATP (D), ADP (E), and AMP (F) are represented as μM per mg of tumor. (G-J) NIC-FF and LKB1 KD cells were subjected to metabolic analyses as in (A-F). Intracellular levels of ATP (G), ADP (H) and AMP (I) are represented in μM per 106 cells. The AMP:ATP ratio (J) in LKB1 KD cells is expressed relative to the ratio for control cells. *, P< 0.05; **, P< 0.01.