NEUROD1 and cell fate plasticity in olfactory neuroblastoma

About This Grant

Project Abstract Olfactory neuroblastoma (ONB), also known as esthesioneuroblastoma, is a rare and life-threatening tumor with limited treatment options. A lack of model systems and limited access to human tissue has hindered progress in understanding the genes, pathways, and mechanisms driving ONB. This project aims to address this critical need by using new genetically-engineered mouse (GEM) and organoid models of ONB to uncover key drivers and mechanisms of cell fate plasticity. We recently created the first GEM model of ONB (Finlay et al, Cancer Cell, 2024) through the loss of tumor suppressors Rb1 and Trp53 and gain of the Myc oncogene in the olfactory epithelium. We have also developed multiple organoid models derived from mouse and human tissue. These models express the neuronal lineage driver NEUROD1, a defining feature of human ONB, along with evidence of intratumoral cell fate heterogeneity. Interestingly, ONB shares molecular states found in small cell lung cancer (SCLC) and prostate neuroendocrine cancer, with remarkable similarity to the ASCL1, NEUROD1, and POU2F3+ states of human SCLC. In this project, we hypothesize that NEUROD1 serves as a master regulator and dependency in ONB, and that its loss will impede tumor growth. However, we anticipate that tumors will evade NEUROD1 loss by adopting non-neuronal fates through the influence of RUNX1 and other transcription factors. Our long-term goal is to identify key genes and pathways driving ONB and to understand the mechanisms underlying cell fate plasticity to ultimately constrain this process. To achieve this, we will pursue two specific aims. First, we will determine the function of NEUROD1 in ONB initiation and progression using in vivo models and organoid transplant models, assessing the impact of NEUROD1 loss on tumor latency, development, and cell fate. Additionally, we will identify NEUROD1 target genes through ChIP-seq analysis and compare them to SCLC, shedding light on similarities and differences between these tissues. Innovative single-cell-based lineage tracing will enable us to investigate the lineage trajectory of tumors escaping NEUROD1 loss. Second, we will determine mechanisms of ONB cell fate plasticity, with a focus on RUNX1. Preliminary data suggest that RUNX1 acts as a master regulator of non-neuronal fates in ONB and normal olfactory neurogenesis. By employing ChIP- seq, genetic knockout and overexpression studies, and single-cell-based lineage tracing, we will identify RUNX1 targets and investigate its impact on ONB growth, progression, and cell fate. This aim will uncover additional predicted regulators of cell fate plasticity. This project's impact lies in the development of innovative new GEM and organoid models that identify NEUROD1 and RUNX1 as master regulators of ONB fate. Furthermore, the mechanisms of ONB cell fate plasticity unraveled here are expected to have relevance for other neuroendocrine cancers including SCLC and prostate neuroendocrine tumors. Ultimately, this knowledge will contribute to improved diagnosis and treatment strategies for both ONB and normal olfaction.