Chloroquine and resveratrol stimulate ATM-independent phosphorylation of AMPK and AKT

It was hypothesized that ataxia telangiectasia mutated (ATM) activators would increase phosphorylation of the AMP‐activated kinase (AMPK) and AKT. To test this hypothesis, C2C12 cells were lentivirally transduced with short hairpin RNA (shRNA) against ATM, which decreased expression of ATM by ~80%. A control C212 cell line was produced by lentiviral transduction with green fluorescent protein (GFP), and non‐transduced C2C12 cells (wild‐type) were also used controls. Myotubes were incubated with or without 500 μM chloroquine, an ATM activator, for one hour. AMPK phosphorylation and AKT‐T308 phosphorylation were stimulated by chloroquine in all cell lines (i.e. wild‐type, cells expressing GFP, and cells expressing shRNA against ATM). In wildtype C2C12 cells, one hour of incubation with 150 μM resveratrol, another ATM activator, increased phosphorylation of AMPK even in the presence of KU55933, a specific inhibitor of ATM. Thus, chloroquine and ATM both cause AMPK and AKT phosphorylation in an ATM‐independent fashion. This work was supported by NIH DK080437 and by NICHD/NCMRR through a Pilot Project subcontract from the National Skeletal Muscle Research Center.