Aldolase a coordinates macropinocytic nutrient scavenging and lysosomal degradation in lung cancer by interacting with V-ATPase.

BACKGROUND: Oncogenic KRAS mutations in cancer cells drive macropinocytosis, a pathway that scavenges extracellular proteins to obtain nutrients under metabolic stress. Lysosomal degradation is essential for processing these proteins, but the precise molecular link between macropinocytic uptake and lysosomal processing remains largely unclear. Aldolase A (ALDOA), a glycolytic enzyme, has diverse non-canonical functions. While interactions between ALDOA and Vacuolar-type H⁺-ATPase (V-ATPase) subunits have been suggested, their functional role in lysosomal degradation of macropinocytosed cargo remains undefined. METHODS: We investigated the role of ALDOA using integrated approaches, including The Cancer Genome Atlas data analysis and in vitro assays of lung adenocarcinoma cell lines to evaluate macropinocytosis, lysosomal degradation, lysosomal pH, and interactions with V-ATPase. We also assessed mTORC1 signaling and cell proliferation under nutrient-deprived and anchorage-independent conditions. In vivo relevance was tested in xenograft tumor models. RESULTS: High expression of ALDOA correlated with a poor prognosis for patients with KRAS-mutant lung adenocarcinoma. Functionally, ALDOA selectively regulated lysosomal degradation of macropinocytosed proteins without affecting their uptake. Mechanistically, ALDOA interacted physically with V-ATPase subunits to increase lysosomal acidification, uncovering a novel, non-enzymatic role that is independent of its glycolytic function. This interaction was essential for efficient nutrient utilization, sustained mTORC1 activity, and cell proliferation under metabolic and mechanical stress. In vivo, depletion of ALDOA inhibited macropinocytosis-dependent tumor growth, phenocopying treatment with 5-(N-Ethyl-N-isopropyl) amiloride. CONCLUSION: Our study identifies a novel, non-enzymatic function of ALDOA as a critical regulator of lysosomal degradation of macropinocytosed proteins via interaction with V-ATPase. This mechanism is essential for metabolic adaptation and growth of KRAS-mutant tumors under stress conditions. Targeting ALDOA offers a promising therapeutic strategy for cancers that rely on extracellular nutrient scavenging.