Ionizing radiation regulates the expression of AMP-activated protein kinase (AMPK) in epithelial cancer cells

AMPK is widely expressed in human normal and cancer epithelial cells and its gene transcription, protein levels, and enzymatic activity is stimulated by IR. Work with AMPKα knockout cells suggests that AMPK (i) may mediate a suppressive regulation on basal expression and activity of ATM and its downstream effector pathways Chk2/p53-p21cip1 and Akt-mTOR, (ii) facilitates the normal response of these pathways to IR and, (iii) mediates the IR-induced G2-M checkpoint.