Abstract
Glioma cells experience profound metabolic stress in hypoxic tumor regions, where mitochondrial respiration is constrained and redox balance becomes difficult to maintain. A recent study by Vettore and colleagues1 in Molecular Cell identifies nicotinamide nucleotide transhydrogenase as a key mitochondrial enzyme that connects NADH oxidation to NADPH production, thereby supporting proline synthesis and growth under hypoxia. This work highlights how distinct redox pools are coordinated in cancer cells and suggests that NNT-dependent metabolism may represent a vulnerability in hypoxic tumors.