Phenformin (Phenethylbiguanide) is an orally active biguanide hypoglycemic agent. Phenformin inhibits mitochondrial respiratory chain complex I, leading to an increased AMP/ATP ratio, activation of AMPK, and subsequent inhibition of the mTOR pathway, thereby suppressing cell proliferation, inducing apoptosis and autophagy. Phenformin inhibits cancer stem cells (CSCs) and possesses potent antitumor potential.
