CD36-Mediated Fatty Acid Oxidation in CTCs Drives Immune Evasion and Metastasis in NSCLC.

Abstract

Background: Immune checkpoint inhibitors (ICIs) show clinical benefit in subsets of non-small cell lung cancer (NSCLC) patients, yet resistance remains a major challenge. Circulating tumor cells (CTCs) contribute to tumor dissemination and immune regulation. This study investigated the metabolic features of CTC subpopulations under PD-1 resistance, with a focus on the role of CD36⁺CTCs in immune evasion and pre-metastatic niche (PMN) formation.

Methods: PD-1-resistant in vitro and murine NSCLC models were established to enrich and isolate CTCs. CD36⁺ CTCs were characterized using lipid metabolomics, RNA sequencing, and functional assays. Their roles in PMN formation and immune suppression were evaluated using lung metastasis models and a tri-cell co-culture system. Fatty acid oxidation (FAO) dependency was assessed by lipid imaging, mitochondrial activity analysis, and pharmacological inhibition with etomoxir.

Results: CD36⁺ CTCs were enriched under PD-1 resistance and exhibited enhanced lipid accumulation, increased mitochondrial activity, and FAO dependency. Multi-omics analyses revealed activation of lipid metabolic pathways associated with immune suppression and extracellular matrix remodeling. Functionally, CD36⁺ CTCs promoted PMN formation and inhibited T-cell activation, while FAO inhibition significantly reduced their migratory and metastatic potential.

Conclusion: CD36⁺ CTCs drive immune evasion and metastasis in PD-1-resistant NSCLC through FAO-dependent metabolic reprogramming. Targeting this metabolic vulnerability may enhance the efficacy of immunotherapy.