PROJECT SUMMARY: The objective of this multi-principal investigator application is to leverage the complimentary expertise of the investigators to develop and credential multiple new mouse models of high-risk, pediatric acute myeloid leukemia (AML). These will include both human and mouse AML with genotypes and cells of origin that are informed by real-world patient data and represent understudied high-risk molecular subtypes of the disease. This proposal will address a pressing clinical and scientific need. Children with AML continue to have an overall poor survival relative to other pediatric cancer patients. Advances in targeted therapies have been slow to develop, and up- front treatment protocols have remained remarkably stagnant for the past 4 decades. Efforts to derive new therapies have lagged, in part due to the marked genetic heterogeneity of pediatric AML. Indeed, we have established that there are over 20 unique molecular subtypes of pediatric AML that reflect unique driver mutations and expression signatures. Pediatric AML also harbor secondary mutations that further exacerbate genetic heterogeneity. Thus, therapies that might benefit patients with one genetic subtype of pediatric AML could have limited value in a different patient population. Unfortunately, current models of pediatric AML do not reflect the marked genomic diversity observed in patients. Current approaches commonly focus on a limited subset of molecular subtypes, typically avoiding rare high-risk subtypes, and they either do not co-model secondary mutations or they implement mutational combinations that are not reflected in patients. Thus, there remains a clear unmet need to advance pediatric AML modeling as a means to expand genetically informed therapeutic options. We will address this need through the completion of three Aims that exploit the unique skills of each investigator’s independent research programs and the exceptional institutional infrastructures at both St. Jude Children’s Research Hospital and Washington University School of Medicine. Aim 1: Develop novel syngeneic mouse models of high-risk pediatric AML; Aim 2: Develop human models of rare pediatric AMLs with patient- informed cooperating mutations; Aim 3. Credential established and newly developed AML models against one another and primary human specimens. To create AML models, we will deploy several innovative genetic strategies, including a novel approach to generate genetically complex murine AML from induced pluripotent stem cells and direct editing of human cord blood progenitors. Credentialing will involve a direct comparison of primary patient material with genetically matched murine and human models based on transcriptomic, epigenomic and proteomic strategies. The high-risk pediatric AML models developed through this comprehensive, cross-species proposal will provide the scientific community with an unparalleled collection of extensively characterized specimens for future investigations into...