Glutamine-derived NADH fuels lactate production to maximize ATP yield under oxygen consumption constraints in head and neck cancer

In head and neck squamous cell carcinoma (HNSCC) cells, low cellular O2 consumption capacity is linked to increased lactate production supported by glutamine-derived NADH, enabling higher ATP yield.

• Why it matters: The work addresses how cancer cells increase lactate output despite oxygen availability, and what metabolic constraints connect oxygen consumption limits to carbon source usage.
• What they did: Using amino acid uptake and [U-13C]-glutamine labeling, plus a cell-line specific metabolic model, the study tested whether glutamine oxidation can fuel lactate via NADH export and lactate dehydrogenase.
• The result: Model predictions and experiments with inhibited mitochondrial respiration confirmed that non-glucose carbon sources support lactate production under decreased O2 consumption capacity, implying a glutamine-driven redox cycle.