NCAPG reprograms glycolytic and lipid metabolism by sustaining glycerophospholipid flux in small-cell lung cancer.

Small-cell lung cancer (SCLC) is characterized by rapid growth and a pronounced neuroendocrine phenotype, accompanied by marked metabolic plasticity. Although metabolic reprogramming is a hallmark of SCLC, the molecular mechanisms coordinating glycolytic and lipid metabolic pathways remain poorly defined. Untargeted metabolomic profiling and RNA sequencing were performed on 46 surgically resected SCLC tissues, 39 paired non-tumorous lung tissues, and corresponding serum samples to identify dysregulated metabolic pathways and key regulatory genes. NCAPG expression and function were evaluated using quantitative real-time PCR, Western blotting, Seahorse extracellular flux analysis, and xenograft mouse models. Cell proliferation, apoptosis, ATP production, and reactive oxygen species (ROS) levels were quantified using standard biochemical and flow cytometric assays. Metabolomic analysis identified 438 significantly altered metabolites in SCLC, including 215 shared between tumor tissues and serum samples, indicating systemic metabolic reprogramming. Pathway enrichment analysis revealed marked activation of glycolysis, glycerophospholipid metabolism, and oxidative phosphorylation. Transcriptomic profiling identified NCAPG as one of the most upregulated genes in SCLC (fold change = 4.7, FDR < 0.001), with elevated expression associated with advanced pathological stage and poor overall survival (HR = 1.47, P = 0.002). Functional depletion of NCAPG in H69 and H446 cells reduced cell viability by 45-60% and increased apoptosis approximately twofold. Seahorse analysis demonstrated a ~ 40% reduction in extracellular acidification rate accompanied by increased oxygen consumption, indicating a metabolic shift from glycolysis toward oxidative phosphorylation. In vivo, NCAPG knockdown suppressed xenograft tumor growth by 58% and significantly downregulated key glycolytic and glycerophospholipid enzymes, including HK2, LDHA, and CHPT1. NCAPG promotes metabolic reprogramming in SCLC by sustaining coupled glycolytic and glycerophospholipid flux, thereby supporting tumor energy production and biosynthetic demands. Targeting this NCAPG-mediated metabolic axis may represent a promising therapeutic strategy for small-cell lung cancer.