STK11 and melanoma: We then tested whether the cryptolepine-induced loss of mitochondrial membrane potential and ATP depletion affects the mass of mitochondria in melanoma cells and/or stimulates an increase in the levels of the energy sensing 5′ adenosine monophosphate-activated protein kinase (AMPKα1/2) and its upstream regulator, the liver kinase B1 (LKB1).