Epigenetic mechanism in mammalian kidney development and tumorigenesis - Project Summary Cellular differentiation during organogenesis relies on precise epigenetic and transcriptional regulation. Disruptions to this regulation can lead to developmental disorders and malignancies. Wilms tumor, the most common kidney cancer in children, accounts for 6% of pediatric cancers and exemplifies the connection between disrupted development and tumorigenesis. While alterations in transcription factors and signaling proteins crucial for kidney development are known drivers for a subset of Wilms tumor cases, recent studies reveal that 30-50% of Wilms tumors harbor mutations in epigenetic regulators, whose function in kidney biology remains unexplored. This project seeks to fill this crucial gap by investigating the role of Eleven-Nineteen-Leukemia (ENL), the most frequently mutated epigenetic regulator in Wilms tumor, in kidney development and cancer. ENL functions as a chromatin reader, binding to histone acetylation through its YEATS domain and recruiting elongation factors to promote transcription. Our recent work shows that hotspot mutations in the ENL YEATS domain, found in Wilms tumor and leukemia, confer gain-of-function properties to ENL, enabling it to drive aberrant gene activation by forming condensates at select target genes. However, the biological functions of ENL and its mutations in normal kidney development and pathogenesis, as well as the underlying mechanisms, remain largely unexplored. We have developed innovative gain- and loss-of-function mouse models for ENL, and preliminary data from these models suggest a critical role of ENL in kidney development. Our central hypothesis posits that proper ENL activity is crucial for normal kidney development, and that gain-of-function ENL mutations disrupt normal differentiation programs, leading to disease states contributing to Wilms tumor formation. We will test this hypothesis using a combination of approaches, including novel genetic mouse models, patient-derived organoids, single-cell transcriptomics/epigenomics profiling, and chemical interventions. Our objectives include determining the biological functions of ENL and its cancer-associated mutations in kidney development at single- cell resolution (Aim 1), investigating the role of the ENL mutation in kidney pathogenesis (Aim 2), and targeting mutant ENL’s pathogenic function in patient-derived Wilms tumor organoids using a potent small-molecule inhibitor we have developed (Aim 3). By elucidating the biological functions and mechanisms of ENL and its mutations, this project will provide new insights into kidney development and pathogenesis, and potentially lead to novel therapeutic strategies. More broadly, these findings will advance our understanding of how epigenetic factors regulate normal differentiation programs and how their aberrations can lead to disease, catalyzing future research into other epigenetic regulators in Wilms tumors and other diseases.
