Potent and selective LSD1 inhibitor DC551040 reveals a promising combination therapy for AML with insight into epigenetic dysregulation

# Potent and selective LSD1 inhibitor DC551040 reveals a promising combination therapy for AML with insight into epigenetic dysregulation *Published: 2026 Mar 23* Epigenetic dysregulation is a fundamental cancer hallmark, and lysine demethylase 1 (LSD1) is a central target for cancer intervention. Developing novel LSD1 inhibitors with high selectivity, favorable bioavailability, and safety for acute myeloid leukemia (AML) remains challenging. We developed DC551040, a highly potent, selective irreversible LSD1 inhibitor with good tolerability in Phase I AML clinical trial (CTR20222026). DC551040-LSD1 complex crystal structure uncovered a new binding pocket, providing molecular insights for subsequent LSD1 inhibitor design. Given the significant role of LSD1 in epigenetic regulation, we performed comprehensive transcriptomic and proteomic analyses to investigate gene and protein expression dynamics following DC551040 treatment in an MV-4-11 xenograft model. These analyses revealed that multiple immune and inflammation related pathways are activated upon DC551040 treatment, including the key members STAT5, NF-κB, and AKT, suggesting the potential for adaptive resistance. Through a search of the Connectivity Map (CMAP) database, we identify homoharringtonine (HHT), an approved anti-leukemia drug, which mimics the anti-transcriptional activation of inflammatory pathways. Subsequent in vitro and in vivo experiments validated the efficacy of combining HHT with DC551040, demonstrating a synergistic antitumor effect and extended survival in MV-4-11 disseminated xenograft model mice. Together, this study not only introduces a novel LSD1 inhibitor but also delves into the molecular mechanisms underlying LSD1 inhibitors, while proposing a promising combination therapy for AML individuals in clinical trials. DOI: 10.1038/s41392-026-02637-0