Abstract 2988: Integrated Functional RNAi Screening and Structural Genomics Identify Cell Cycle and Kinetochore Components Co-Modulating NF-κB Activity As Potential Therapeutic Targets in Head and Neck Squamous Cell Carcinoma

Abstract Head and neck squamous cell carcinoma (HNSCC) is the sixth most common cancer worldwide, with over 600,000 new cases diagnosed each year, and a five year survival of ∼50%. Recent findings in The Cancer Genome Atlas (TCGA) analysis of 279 HNSCC patient samples revealed that components of the NF-κB/REL signaling pathways are aberrantly expressed in about ∼70% of cases, and implicated in expression of pro-proliferative, inflammatory, angiogenic, and therapeutic resistance genes. Alterations are prevalent in this pathway across patient samples; however, the detailed mechanisms that increase NF-κB signaling in HNSCC are not well understood. Recently, we established an NF-κB β-lactamase reporter UM-SCC-1 cell line to identify key regulators of this NF-κB oncogenic signaling. We performed genome-wide RNAi screening using the NF-κB reporter line, and upon validation, most structural components of the TNF receptor complex and downstream NF-κB pathway genes, such as IKKs, were scored highly in the screening. We integrated the functional genomics data with structural mutation and expression data from TCGA to prioritize genes that are frequently deregulated in HNSCC specimens. WNT9/FZD6, NOTCH2, and TGFβR2 and several receptors were identified to cross-activate NF-κB signaling. In addition, we observed novel genes that co-regulate NF-κB activity, which are involved in the cell cycle, such as CDC2, CDC7, WEE1 and CALM2, as well as components of the kinetochore such as NDC80, PLK1, TTK, and AURKA. Among these targets WEE1 kinase is currently under investigation as a therapeutic target in HNSCC using the WEE1 inhibitor AZD1775. To further investigate potential cross-talk between WEE1 cell cycle regulation and NF-κB activation, we have shown that treatment of HNSCC cells with AZD1775 decreases NF-κB transcriptional activation which corresponds to decrease in TNF-inducible phosphorylation of RELA. These changes also correlate with alteration in cell cycle regulation detected by flow cytometry. Mechanistic studies are currently underway to understand how WEE1 signaling connects to NF-κB activation, and what role inhibition of NF-κB signaling plays in AZD1775 activity as a sensitizer to chemo-or radiation therapy for HNSCC. Supported by NIDCD intramural projects ZIA-DC-000073,74 Citation Format: Anthony D. Saleh, Sophie Carlson, Shaleeka Cornelius, Hui Cheng, Scott Martin, Pinar Ormanoglu. Integrated functional RNAi screening and structural genomics identify cell cycle and kinetochore components co-modulating NF-κB activity as potential therapeutic targets in head and neck squamous cell carcinoma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2988.