NPM1 mutation promotes creatine anabolism by FTO-dependent m6A demethylation to drive macrophage M2 polarization in acute myeloid leukemia.

Nucleophosmin 1-mutant (NPM1MU) acute myeloid leukemia (AML) represents a distinct molecular subtype, yet the mechanisms underlying NPM1 mutation-driven malignant transformation remain incompletely understood. Here, we find prevalent copy number variations (CNVs) of N6-methyladenosine (m6A) key regulators in NPM1 wild-type (NPM1WT) AML patients, whereas such alterations are rarely detected in NPM1MU subgroup. Moreover, a reduction in m6A modification is observed in leukemic cells overexpressing NPM1MU protein, concomitant with an increase in FTO expression. Co-immunoprecipitation shows that NPM1MU protein mislocates in the cytoplasm and binds to FTO to block its ubiquitin-proteasome degradation through K422 specific site. Of note, creatine metabolism-related signaling and FTO-mediated macrophage M2 polarization signaling are enriched in NPM1MU patients according to TCGA data analysis. Indeed, FTO promotes creatine anabolism in NPM1MU leukemic cells by stabilizing the mRNA of GAMT, a key enzyme in the creatine synthesis pathway. Creatine facilitates macrophage M2 polarization, as evidenced by the upregulation of M2 polarization-related genes (CD206, CCL2, IL-10 and CXCL13). This effect is abrogated upon FTO knockdown in leukemic cells. Selinexor, an exportin 1 inhibitor to impede NPM1MU export from nucleus, enhances FTO degradation and reduces macrophage M2 polarization. This work reveals that FTO-creatine signaling plays an oncogenic role in NPM1MU AML, guiding more effective therapy strategies and clinical benefits for this distinctly leukemic entity.