RPMI 2650 cell transfected with empty vector, wild-type or mutant Stk11/Lkb1 were treated with or without 0.1 mM H2O2 for 20 min. Western blotting was performed as previously described. Total cell extracts were immunoblotted with antibodies for phosphor-Thr-172 AMPK (p-AMPK) (Cell Signaling, 1:1,000 dilution), total AMPK (Cell Signaling, 1:1,000 dilution) and Stk11 (Cell Signaling, 1:1,000 dilution).