Abstract 2004: Understanding the role of α1,2-fucosylation in head and neck cancer

Abstract

Abstract Head and neck cancer is the seventh most common cancer in the world, claiming ~500,000 deaths yearly. Low expression of FUT2, an α1,2-fucosyltransferase that modifies glycoproteins and glycolipids, is associated with lower overall survival in head and neck squamous cell carcinoma (HNSCC). We previously showed that inhibition of nuclear β-catenin/CBP led to an increase in antennary fucosylation of the epidermal growth factor receptor (EGFR) and reduced tumor growth in a mouse orthotopic tumor xenograft model of HNSCC (Chandler KB et al., 2020). One possible explanation for this finding could be attenuation of HNSCC cellular proliferation and survival via restoration of fucose modification-mediated regulation of cell signaling and adhesion, leading to reinforcement of epithelial cell characteristics. To explore this hypothesis, FUT2 was overexpressed in the metastatic HNSCC cell line HSC-3. To compare the rate of proliferation between empty vector (HSC-3-EV) and FUT2-overexpressing cells (HSC-3-FT2), cells were plated in triplicate and photographed every 24 hours using an EVOS Imaging System. Independently, indolent CAL27 cells with high endogenous FUT2 expression and HSC-3-FT2 cells were subject to flow cytometry analyses to probe for fucosylated epitopes on the cell surface. To identify proteins bearing fucosylated determinants, CAL27 and HSC-3 cell lysates were subjected to proteolysis and analyzed via liquid chromatography-tandem mass spectrometry (LC-MS/MS). MS/MS data were searched with PEAKS software (Bioinformatics Solutions, Inc.), and with Byonic (Protein Metrics). Forced expression of FUT2 in HSC-3 cells (HSC-3-FT2) led to a decrease in proliferation compared to HSC-3-EV cells. Flow cytometry analyses revealed the presence of α1,2-fucosylated glycan epitopes on the cell surface of CAL27 cells, but not on parental HSC-3 or HSC-3-EV cells. To probe the role of FUT2 in HNSCC, we sought to identify fucosylated proteins in HNSCC cell lines by applying proteomic and glycoproteomic analyses of CAL27 and HSC-3 cell lysates to identify glycoproteins with differential display of fucosylated epitopes. Among the 1379 proteins in CAL27 cells and 1340 proteins in parental HSC-3 cells (1% FDR cutoff), with 1137 proteins common to both cell lines, we detected at least one glycopeptide for 55 proteins. Adhesion molecules and cell surface receptors were over-represented in the set and will serve as the focus of future inquiry into the mechanism of FUT2-mediated survival in HNSCC. In conclusion, FUT2 overexpression decreases cell proliferation in HSC-3 tongue squamous carcinoma cells. Low endogenous levels of α1,2-fucosylated epitopes were detected on HSC-3 cells with demonstrated metastatic potential, while higher levels were detected on non-metastatic CAL27 cells that express FUT2. We plan to further investigate the role of FUT2 in HNSCC, by exploring the impact of α1,2-fucose modification on signaling and adhesion molecules. Citation Format: Evan Ales, Bach-Cuc Nguyen, Winston H. Elliott, Maria A. Kukuruzinska, Catherine E. Costello, Robert Sackstein, Kevin Brown Chandler. Understanding the role of α1,2-fucosylation in head and neck cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2004.