A Multiplatform Approach to Develop ENL-Targeting Molecules as Drug Candidates for Acute Myeloid Leukemia - PROJECT SUMMARY/ABSTRACT Acute myeloid leukemia (AML), a blood and bone marrow malignancy, manifests as an aggressive disease that requires immediate treatment. A key player in AML is the mixed-lineage leukemia gene (MLL or KMT2A), found on chromosome 11q23. Mutations in MLL frequently correlate with poor prognosis, prompting a need for therapeutics that can effectively target these genetic alterations. MLL is known to combine with over 80 genes, creating chimeric proteins implicated in AML. Among these, ENL, a component of the YEATS protein family, has been identified as essential for maintaining the dysregulated gene expressions that drive leukemogenesis. Targeting the ENL YEATS domain, a unique structure that forms an open-end epigenetic reader pocket, offers a promising therapeutic avenue. Despite significant strides made in developing small molecule inhibitors targeting ENL YEATS, these compounds suffer from limited efficacy, lack of selectivity, and metabolic instability. The PI’s team has previously developed a number of potent small molecule ENL inhibitors. By coupling a newly designed NanoBRET system for their cellular potency analyses, they identified a promising compound (Cmpd 13) that demonstrated favorable characteristics for further in vivo pharmacokinetic and animal efficacy studies. Notably, Cmpd 13 significantly improved survival time for MOLM-13 xenografted mice, establishing it as a potential orally administered therapy. In parallel, the PI’s team has also used a uniquely developed phage display technique, in combination with medicinal chemistry, to identify a potent peptidic ENL YEATS inhibitor, tENL-S1f, that has high cellular permeability and significant in vitro anti-leukemia effects. Additionally, the PI’s team capitalized on the (Proteolysis Targeting Chimera) PROTAC technology, a breakthrough in targeted protein degradation. Using this strategy, they designed a potent PROTAC, Gxj-47, that successfully eliminated AML cells while demonstrating low cellular toxicity. Built on strong preliminary results, the PI’s team propose to significantly expand their multiplatform strategy for the development of ENL inhibitors and PROTACs by pursuing three primary objectives: 1) To develop more potent, stable, and selective small molecule ENL inhibitors and PROTACs; 2) To develop more potent, stable, and selective peptidic ENL inhibitors and PROTACs; 3) To perform rigorous pharmacokinetic/ pharmacodynamic analyses on these molecules, aiming to identify potential Investigational New Drugs (INDs) for MLL-rearranged AML. If successful, this research holds the potential to revolutionize AML treatment, providing a significant shift in treatment modalities, increasing survival rates, and improving patients' quality of life. This research could also serve as a pioneering blueprint for drug development in diseases with similar genetic alterations, thus having broader implications in the field of targeted therapy development.
