Abstract A31: Deregulation of NOTCH 1/NR4A2 signaling axis in head and neck cancer pathogenesis

Background: Notch1 and its intracellular cytoplasmic domain (NICD) are dysregulated in many solid tumors, including head and neck squamous cell carcinoma (HNSCC), and associated with disease initiation and progression. NICD-mediated upregulation of nuclear receptor related 1 (NURR1/NR4A2) is linked to differentiation/development, homeostasis, and cellular metabolism. However, the role and molecular mechanism(s) of Notch1/NICD- NR4A2 axis in HNSCC pathogenesis are still unknown and need to be investigated. Methods: The clinicopathologic importance of Notch1 and NR4A2 was investigated using HNSCC patient samples and publicly available databases. NR4A2 was stably knocked out (KO) and Notch1 signaling was blocked using small-molecule inhibitor (PF3084014) in HNSCC cell lines and analyzed for tumorigenic and metastatic potential. We also examined the whole-genome NR4A2 target genes using ChIP sequencing. Results: Both Notch1 and NR4A2 were highly overexpressed in HNSCC patients. Inhibition of Notch1 signaling or NR4A2 KO significantly decreased the clonogenicity and migratory potential of HNSCC cells. Our ChIP analysis revealed that NR4A2 regulates genes involved in metabolism, hypoxia, cell cycle progression, integrin and Wnt signaling. Interestingly, we observed that NR4A2 regulates stem cell markers including Sox2, Nanog, and CD44 and their expression was drastically reduced upon Notch 1 inhibition. Conclusion: Targeting Notch1-NR4A2 signaling axis may be crucial for inhibition of cancer stem cell-mediated HNSCC pathogenesis. Citation Format: Sanjib Chaudhary, Ramesh Pothuraju, Zafar Sayed, Dwight T. Jones, Surinder K. Batra, Muzafar A. Macha. Deregulation of NOTCH 1/NR4A2 signaling axis in head and neck cancer pathogenesis [abstract]. In: Proceedings of the AACR-AHNS Head and Neck Cancer Conference: Optimizing Survival and Quality of Life through Basic, Clinical, and Translational Research; 2019 Apr 29-30; Austin, TX. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(12_Suppl_2):Abstract nr A31.