Metabolic reprogramming via LDHB confers resistance to lactate-induced dysfunction and enhanced antitumor activity in hiPSC-Derived NK cells.

Natural Killer (NK) cells generally exhibit dysfunction in tumor microenvironment (TME), significantly limiting their efficacy in antitumor therapy. Tumor cells display enhanced glycolysis, leading to lactic acid (LA) secretion and accumulation in the TME. Using human-induced pluripotent stem cell (hiPSC)-derived NK cells (iNKs) as a model, we demonstrate that LA induces substantial iNK dysfunction, including reduced survival, impaired IFN-γ secretion, and diminished tumor-killing capacity due to severely compromised mitochondrial function. To overcome LA-induced dysfunction, we knocked in an expression cassette for lactate dehydrogenase B (LDHB) into hiPSCs (LDHB-hiPSCs), enabling conversion of cellular lactate to pyruvate. iNKs derived from LDHB-hiPSCs (LDHB-iNKs) largely resisted LA-induced dysfunction, exhibiting enhanced cytotoxicity and improved survival in high-LA tumor tissues. Importantly, LDHB-iNKs show superior suppression of solid tumor formation in vivo. Our study provides a novel strategy to enhance NK cell therapy against solid tumors by reshaping the metabolic pathways.