Targeting DCAF5 restores p53 tumor suppressor function and exerts anti-leukemic effects in AML

Abstract Background: Acute myeloid leukemia (AML) remains a therapeutic challenge due to its genetic complexity and frequent resistance to conventional therapies, frequently associated with impaired tumor suppressor function. DCAF5 (DDB1-CUL4-associated factor 5), a substrate receptor for the CRL4 E3 ubiquitin ligase complex, has been implicated in maintaining oncogenic states through degradation of tumor suppressor complexes, while its biological and therapeutic relevance in AML pathogenesis remains undefined. Purpose: This study aimed to(1) define the functional role of DCAF5 in AML maintenance, (2)elucidate the mechanistic relationship between DCAF5 and p53 regulation, (3)evaluate the therapeutic potential of combined DCAF5 targeting and MDM2 inhibition. Methods: DCAF5 expression and its correlation with clinical outcomes were analyzed in AML patient cohorts using publicly available datasets and patient-derived samples. Genetic perturbation of DCAF5 was performed in AML cell lines using CRISPR/Cas9. In vitro and in vivo AML models were employed to investigate the functional role of DCAF5. Protein interactions were characterized by co-immunoprecipitation and mass spectrometry, while p53 stability was assessed through ubiquitination assays and cycloheximide chase experiments. Functional consequences were evaluated using apoptosis, cell cycle, and differentiation assays. The therapeutic potential was further validated in patient-derived xenograft (PDX) models. Results: DCAF5 expression was significantly elevated in AML and correlated with poor prognosis. Genetic ablation of DCAF5 induced potent anti-leukemic effects, including cell cycle arrest, apoptosis, and myeloid differentiation. Mechanistically, DCAF5 directly interacts with p53, promoting its ubiquitin-mediated proteasomal degradation, consequently suppressing p53 transcriptional networks, while DCAF5 konckout substantially restores p53 related transcriptional expression profile and tumor suppressor function. Strikingly, combined DCAF5 targeting and MDM2 inhibition elicited synergistic lethality both in vitro and in vivo, with reducing leukemic burden and extending survival in AML PDX. Conclusion: Collectively, our study establishes DCAF5 as a critical oncogenic driver in AML through its regulation of p53 proteostasis. DCAF5 ablation reactivates p53 tumor suppressor function and exerts anti-leukemic effects. The mechanistic elucidation of the DCAF5-p53 axis provides preclinical evidence supporting the development of DCAF5 -targeted strategies, particularly for enhancing MDM2 inhibitor sensitivity in AML.