The role of ENL mutations in kidney development and tumorigenesis

Wilms tumor is the most common pediatric renal tumor, primarily affecting children under the age of 5. It is closely linked to disrupted nephrogenesis and features rudimentary structures found in the developing kidney. While alterations in transcription factors and signaling proteins crucial for kidney development are known molecular drivers, recent studies have revealed that 30-50% of Wilms tumor patients have mutations in epigenetic regulators, with ENL (Eleven-Nineteen Leukemia) being the most frequently mutated. The role of these epigenetic regulators in kidney differentiation and tumorigenesis remains unexplored. This study aims to fill this gap by exploring the role of ENL mutations in nephrogenesis and Wilms tumor development. ENL is a chromatin reader protein which binds histone acetylation through its YEATS domain to recruit co-factors and drive transcriptional elongation. Hotspot mutations in the ENL YEATS domain have been identified in Wilms tumor. These mutations result in hyperactivation of target gene transcription by the formation of high local concentration assemblies termed condensates. To study the role of ENL mutations in Wilms tumor, our lab developed a conditional knock-in mouse model for the most frequent Enl mutation, referred to as Enl-T1. We crossed these mice to the Wt1-Cre strain to induce heterozygous expression of Enl-T1 in the nephron and stroma lineages of the developing kidney. These mice displayed aberrant kidney development with the loss of differentiated nephron structures and post-natal lethality. Single-cell analyses of transcriptomics and open chromatin accessibility revealed that Enl-T1 shifts nephron progenitor cells toward an aberrantly committed state while restricting their further differentiation. Enl-T1 expression also disrupted stromal progenitor cell differentiation, suggesting a role for ENL in both stromal and nephron progenitor populations. Notably, the developmental defects and transcriptional changes induced by Enl-T1 can be rescued by treatment with TDI-11055, an inhibitor that blocks the interaction of ENL-T1 with acetylated histones. Based on these findings, I hypothesize that an optimal level of ENL activity is critical for normal kidney development, and disruptions to this balance through gain-of-function mutations in ENL can lead to tumor formation. I will investigate the role of the Enl-T1 in nephrogenesis and tumorigenesis using lineage specific cre drivers (Aim 1) and determine the impact of the ENL mutant inhibition, using TDI-11055, on Wilms tumor maintenance (Aim 2) through a combination of mouse modeling, histological analysis, single cell transcriptomics, and patient-derived Wilms tumor organoids. These studies will elucidate the role of Enl mutations in kidney development and disease, identify a novel therapeutic target in Wilms tumor, and provide new insights into how epigenetic regulation plays a role in cell differentiation in normal and diseased contexts. Project Number: 1F31CA306054-01 | Fiscal Year: 2025 | NIH Institute/Center: National Cancer Institute (NCI) | Principal Investigator: Arushi Sahay | Institution: UNIVERSITY OF PENNSYLVANIA, PHILADELPHIA, PA | Award Amount: $49,538 | Activity Code: F31 | Study Section: Special Emphasis Panel[ZRG1 F09A-R (20)] View on NIH RePORTER: https://reporter.nih.gov/project-details/11241800