Head and neck squamous cell carcinoma (HNSCC) is a heterogeneous disease with low survival rates, which have not significantly improved despite advances in surgery and radiotherapy. Although human papillomavirus is a strong predictor of outcomes in oropharyngeal tumors, other HNSCC subtypes lack reliable prognostic and therapeutic biomarkers. The purpose of this study was to identify molecular targets to improve the management of oral cavity SCC (OSCC). We isolated RNA from 19 OSCCs treated surgically at UAB and evaluated gene expression using the NanoString nCounter system and PanCancer Pathways analysis module. Results were confirmed using data from the oral cavity anatomic subdivision of the Head and Neck Squamous Cell Carcinoma cancer study generated by the TCGA Research Network. Associated in vitro phenotype was assessed in HNSCC cell lines UM-SCC1, UM-SCC6 and FaDu treated with the activating Notch ligand DLL4 and included evaluation of gene expression, proliferation, cell cycle, migration, invasion, and radiosensitivity. We identified a significant association between upregulation of the Notch pathway and mortality in both the UAB and TCGA OSCC sample sets. In vitro activation of Notch signaling altered transcription in a pattern similar to that found in patient samples from the mortality cohorts. HNSCC cells with Notch activation had increased expression of pro-invasive genes FGF1, IL1B, SIX1, and CCNA1. In addition, Notch activated cells displayed increased cell migration and invasion. Proliferation, cell cycle distribution, and radiosensitivity were unchanged in ligand-treated cells. Our results identify a subset of OSCC patients who have increased Notch pathway activity and worsened outcomes. These clinical findings may reflect a more invasive cell phenotype driven by Notch-mediated changes in transcription. Additional studies are needed to fully elucidate the mechanism underlying this association and to investigate the efficacy of therapies targeting Notch signaling in OSCC.

Citation Format: Alice N. Weaver, Tiffiny S. Cooper, Deborah Della Manna, Shi Wei, Eben L. Rosenthal, Eddy S. Yang. Upregulation of the Notch signaling pathway is associated with mortality and in vitro cell invasion in squamous cell carcinoma of the oral cavity. [abstract]. In: Proceedings of the AACR Precision Medicine Series: Targeting the Vulnerabilities of Cancer; May 16-19, 2016; Miami, FL. Philadelphia (PA): AACR; Clin Cancer Res 2017;23(1_Suppl):Abstract nr A32.