In vitro and in vivo experiments in cancer cells demonstrated that forkhead box O3 (FOXO3) is a critical transcription factor under metabolic stress that, under this condition, is translocated in a cleaved form into mitochondria to support mitochondrial metabolism; however, MTF treatment mediated proapoptotic effects on mitochondrial FOXO3 via AMPK [64]. This evidence concerns the gene PRKAA2 and cancer.