Inhibition of USP5 offers potential targeted therapeutic strategies for t(8;21) AML through ubiquitin-mediated degradation of AML1-ETO

The AML1-ETO (AE) fusion protein is a key target for treating t(8;21) acute myeloid leukemia (AML). In this investigation, we identified ubiquitin-specific protease 5 (USP5) as the deubiquitinating enzyme of AE. USP5 knockdown decreased AML cell growth and induced differentiation both in vitro and in vivo. Additionally, we developed a high-throughput screening (HTS) method and identified a potent, selective USP5 inhibitor, WCY-8-67. This lead compound was identified as a selective USP5 inhibitor via targeting the ubiquitin-associated domain 2 (UBA2) region, and it also induced aggregation and precipitation of the target protein, leading to USP5 dysfunction. WCY-8-67 was exhibited excellent in vivo bioavailability and tolerability, and it effectively inhibited the growth of t(8;21) AML cell lines and the primary AML cells in animal models. Notably, in the patient-derived xenograft (PDX) model, this compound, when combined with 5-Azacytidine (5-Aza), demonstrated good safety and significant synergistic therapeutic effects. This study presented promising targeted therapeutic possibilities for the treatment of t(8;21) AML.