Abstract

Nucleophosmin 1-mutant (NPM1 MU ) 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 N 6 -methyladenosine (m 6 A) key regulators in NPM1 wild-type (NPM1 WT ) AML patients, whereas such alterations are rarely detected in NPM1 MU subgroup. Moreover, a reduction in m 6 A modification is observed in leukemic cells overexpressing NPM1 MU protein, concomitant with an increase in FTO expression. Co-immunoprecipitation shows that NPM1 MU 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 NPM1 MU patients according to TCGA data analysis. Indeed, FTO promotes creatine anabolism in NPM1 MU leukemic cells by stabilizing the mRNA of GAMT, a key enzyme in the creatine synthesis pathway. Creatine facilitates macrophage M2 polarization via SLC6A8-mediated transport, as evidenced by the upregulation of M2 polarization markers (CD206, CCL2, IL-10 and CXCL13). This effect is abrogated upon FTO knockdown in leukemic cells. Selinexor, an exportin 1 inhibitor to impede NPM1 MU export from nucleus, enhances FTO degradation and reduces macrophage M2 polarization. This work reveals that FTO-creatine signaling plays an oncogenic role in NPM1 MU AML, guiding more effective therapy strategies and clinical benefits for this distinctly leukemic entity.