Deciphering and Targeting Epigenetic Accessory Proteins in Acute myeloid Leukemia - SUMMARY Epigenetic complexes are composed of catalytic core enzymes and accessory proteins that work together to regulate gene expression and contribute to cancer development. Most existing therapies target the catalytic cores, often leading to widespread chromatin disruption and unwanted toxicity. In contrast, selectively modulating accessory proteins that fine-tune complex activity and chromatin targeting may provide a more precise and safer therapeutic strategy, yet their functions and potential as drug targets remain largely unexplored. This project focuses on acute myeloid leukemia (AML), a highly aggressive cancer characterized by the uncontrolled proliferation of immature myeloid cells. With over 20,000 new cases each year in the U.S. and a low survival rate of about 30%, there is an urgent need for more effective targeted therapies. Menin inhibitors, which block the Menin-KMT2A interaction, have shown promise in KMT2A-rearranged (KMT2A-r) and NPM1-mutant AML, but emerging resistance highlights the need for deeper insight into Menin-mediated gene regulation. Through an unbiased, reporter-based CRISPR screen, we identified JADE2, an epigenetic accessory component of the KAT7 histone acetyltransferase complex, as a novel regulator of KMT2A-Menin target genes. Our extensive preliminary data demonstrate that JADE2 is a unique component of the KAT7 complex that is selectively required for KMT2A-r AML and modulates the response to Menin inhibition. Importantly, unlike the enzymatic core KAT7, JADE2 depletion does not affect global histone acetylation or normal hematopoietic stem and progenitor cells, highlighting its potential as a selective target. Moreover, saturated CRISPR tiling screens and domain truncation analyses have mapped the regions of JADE2 responsible for chromatin targeting and interaction with the Menin-KMT2A complex, revealing potential druggable sites. The goal of this project is to define how JADE2 regulates leukemia-driving gene programs and therapeutic response in AML, and to characterize its key functional domains that could be leveraged for future drug development. To achieve this, we will first define how JADE2 recognizes and binds chromatin and determine its direct effects on gene regulation using an acute protein degradation system (Aim 1). We will then elucidate how JADE2 interacts with the Menin-KMT2A complex and controls its target genes through integrated biochemical, genetic, and genomic approaches (Aim 2). Finally, we will assess how JADE2 influences the AML response to Menin inhibition and test the therapeutic potential of combined JADE2-Menin targeting in preclinical models (Aim 3). We will use New Approach Methodologies whenever possible, including cell-based, genomic, and biochemical systems. However, these approaches cannot adequately model AML progression and therapeutic response in vivo, necessitating the limited use of animal models in this project. Together, these studies will address critical knowledge gaps and have high impact by uncovering new mechanisms of gene regulation in AML and establishing JADE2 as a promising, druggable target for therapeutic development.
