Abstract 4151: Interleukin 17 promotes tumor progression in oral squamous cell carcinoma

Abstract

Background: Interleukin 17 (IL17) is a proinflammatory cytokine with increased expression in some cancers. It has been demonstrated to exhibit both pro- and anti-tumor effects. Our group has previously demonstrated expression of IL17 from multiple cells in oral squamous cell carcinoma (OSCC) such that the aim of the current study was to examine the role of IL17 in OSCC progression. Methods: The cytoplasmic SEFIR sequence of the transmembrane IL17 receptor (IL17R) was detected in formalin Fixed Paraffin Embedded (FFPE) OSCC tissues (n = 14) using immunohistochemistry. Soluble IL17R was detected in the cell culture supernatants of three OSCC cell lines (SCC4, SCC15 and SCC25) using a sandwich ELISA. Human recombinant IL17 over a range of concentrations (0, 10, 50, 100 ng/mL) was used to stimulate the three OSCC cell lines.Proliferation at 0, 24, 48, 72 hours was then assayed by cell titer blue and invasion at 48 hours using a QCM ECMatrix cell invasion assay. The data were analyzed using unpaired Student's t test and ANOVA as appropriate using GraphPad Prism 6 software. Results:Cytoplasmic expression of transmembrane IL17R was detected in all FFPE OSCC tissues. Soluble IL17R was detected in the cell culture supernatants of all three OSCC cell lines and its concentration increased in a time dependent manner. SCC25 had significantly higher concentration of soluble IL17R at 72 hours than SCC4 and SCC15. The rate of proliferation of all three OSCC cell lines was not affected with the addition of recombinant IL17. However, IL17 promoted the in vitro invasion of SCC25 and SCC15 in a dose dependent manner. At the highest concentration of IL17 (100ng/mL), the SCC25 cells showed significant invasion compared to control cells (p<0.05), while the SCC15 cells exhibited significant invasion at both 50ng/mL and 100 ng/mL of IL17 (p<0.05). In contrast, IL17 failed to stimulate invasion in the SCC4 cell line. Conclusions: This study is the first to demonstrate in vitro association between IL17 and possible invasion of OSCC. The exact mechanism by which IL17 enhances invasion and thereby tumor progression in vivo remains to be elucidated and could involve a number of different mechanisms including cell adhesion and extracellular matrix proteins. Citation Format: Avadhoot Avadhani, Trudy Milne, Gregory Seymour, Alison Rich. Interleukin 17 promotes tumor progression in oral squamous cell carcinoma. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4151. doi:10.1158/1538-7445.AM2015-4151