The Fbxw11-Dpysl2 ubiquitin axis restrains the progression of acute myeloid leukemia.

Ubiquitination regulation is essential for maintaining protein homeostasis. Dysregulated ubiquitination is increasingly recognized to participate in malignant progression. Fbxw11, a substrate-recognition subunit of SCF-type E3 ligases, is involved in tumorigenesis and progression. However, its role and molecular mechanism in acute myeloid leukemia (AML) have not been elucidated. Here we demonstrat that lower levels of Fbxw11 were detected in AML patients and correlated with worse prognosis. Furthermore, overexpression of Fbxw11 delayed AML progression by reducing leukemia stem cell (LSC) frequency and inhibiting leukemia cell migration. Mechanistically‌, quantitative proteomics combined with co-immunoprecipitation and ubiquitination assays identified dihydropyrimidinase-like 2 (Dpysl2) as a direct substrate of Fbxw11, leading to its poly-ubiquitylation and proteasomal degradation. Moreover, overexpression of Dpysl2 reversed the effects of Fbxw11 on LSC levels and migration of AML cells as well as accelerated AML progression in vivo. In addition, inhibition of Dpysl2 with lacosamide, an FDA-approved antiepileptic drug, phenocopied Fbxw11 restoration and delayed AML progression. Lacosamide combined with cytarabine further prolonged the survival of AML mice. Our results suggest Fbxw11 as an intrinsic suppressor in AML progression by regulating the ubiquitination and degradation of Dpysl2, providing new insights into ubiquitination regulation and highlighting the potential of targeting the Fbxw11-Dpysl2 axis as a therapeutic strategy for AML.