Leptin decreases Th17/Treg ratio to facilitate neuroblastoma via inhibiting long-chain fatty acid catabolism in tumor cells

The exploration of therapeutic targets in neuroblastoma (NB), which needs more attempts, can benefit patients with high-risk NB. Based on metabolomic and transcriptomic data in mediastinal NB tissues, we found that the content of long-chain acylcarnitine (LCAC) was increased and positively associated with leptin expression in advanced NB. Leptin over-expression forced naïve CD4+ T cells to differentiate into Treg cells instead of Th17 cells, which benefited from NB cell proliferation, migration, and drug resistance. Mechanically, leptin in NB cells blunted the activity of carnitine palmitoyltransferase 2 (CPT2), the key enzyme for LCAC catabolism, by inhibiting sirtuin 3-mediated CPT2 deacetylation, which depresses oxidative phosphorylation (OXPHOS) for energy supply and increases lactic acid (LA) production from glycolysis to modulate CD4+ T cell differentiation. These findings highlight that excess leptin contributes to lipid metabolism dysfunction in NB cells and subsequently misdirects CD4+ T cell differentiation in tumor micro-environment (TME), indicating that targeting leptin could be a therapeutic strategy for retarding NB progression.