Lactate mitochondrial oxidation drives stemness potential in metastatic breast cancer.

Metastatic cancer cells, originating from cancer stem cells with metastatic capacity, utilize nutrient flexibility to navigate the challenges of the metastatic cascade. However, the nutrient required to maintain the stemness potentials of metastatic cancer cells remains unclear. Here, we reveal that metastatic breast cancer cells sustain stemness and initiate metastasis upon detachment by taking up and oxidizing lactate. In detached metastasizing breast cancer cells, lactate is incorporated into the tricarboxylic acid cycle, boosting oxidative phosphorylation, and promoting the stemness potentials via α-KG-DNMT3B-mediated SOX2 hypomethylation. Moreover, lactate is taken up and oxidized in mitochondria by the CD147/MCT1/LDHB complex, which correlates with stemness potentials and tumor metastasis in patients with breast cancer. An intracellularly expressed single-chain variable fragment targeting mitochondrial CD147 (mito-CD147 scFv) effectively disrupts the mitochondrial CD147/MCT1/LDHB complex, inhibits lactate-induced stemness potential, depletes circulating breast cancer cells, and reduces metastatic burden, suggesting promising clinical applications in reducing lactate-fueled metastasis.