Abstract 454: Leveraging cell cycle to enhance differentiation therapy in acute myeloid leukemia

Acute myeloid leukemia (AML) is a highly heterogeneous hematological malignancy characterized by diverse genetic and epigenetic aberrations, making therapeutic interventions particularly challenging. We have identified a novel combination therapy that leverages differences in cell cycle dynamics to induce AML cell differentiation, and found AML cells which were highly sensitive to inhibitors of the histone demethylase LSD1/KDM1A depending on their cell cycle profile. Here, we aim at identifying other potential epigenetic vulnerabilities of AML cell lines exposed to the treatment with different CDK inhibitors. Given the heterogeneity of the epigenetic aberrations found in AML, targeting additional chromatin regulators could improve the clinical applicability of this combination therapy. Thus, we started an in vitro CRISPR-screening approach, targeting over 600 chromatin-related genes. Following optimization of Cas9-expressing clones and evaluation of knockout (KO) efficiency, we confirmed that the best-performing clone retained phenotypic consistency with parental cells under combination therapy. Preliminary data validated the effectiveness of our screening platform, as sgRNAs targeting LSD1 recapitulated the phenotype observed with CDK inhibitors treatment, thereby demonstrating the feasibility of the approach. In parallel, we investigated the molecular link between cell cycle manipulation and chromatin remodeling. We conducted a nuclear phospho-proteomics experiment on cells treated with CDK inhibitors. This analysis identified differential phosphorylation of several proteins, which are currently under investigation. Additionally, gene ontology analysis revealed enrichment in pathways regulating RNA metabolism, transcription, and DNA damage response. By integrating cell cycle modulation with epigenetic targeting, our work offers new insights into AML differentiation therapy, with the potential to improve therapeutic outcomes in diverse AML subtypes. Citation Format: Riccardo Valzelli, Kourosh Hayatigolkhatmi, Amir Hosseini, Elena Ceccacci, Giorgia Parodi, Angela Bachi, Saverio Minucci. Leveraging cell cycle to enhance differentiation therapy in acute myeloid leukemia [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 454.