Abstract 5734: Interleukin-1 signaling is required for HNSCC tumor response to cetuximab

Abstract

Abstract Despite the incorporation of the epidermal growth factor receptor (EGFR) inhibitor cetuximab into the clinical management of head and neck squamous cell carcinoma (HNSCC), limited to no long-term changes in overall survival are observed in HNSCC patients even though EGFR is expressed at high levels in these tumors. Therefore, the identification of novel therapeutic approaches to enhance the clinical efficacy of cetuximab could lead to improved long-term survival for HNSCC patients. Our previous work suggests that cetuximab activates the interleukin-1 (IL-1) pathway via tumor release of IL-1 alpha (IL-1α), although the implications of activating this pathway are unclear. The IL-1 pathway plays a central role in immune response and displays both pro-tumor and anti-tumor activities. IL-1 may promote tumor growth by upregulating the secretion of pro-inflammatory mediators involved in angiogenesis and metastasis. On the other hand, IL-1 signaling may promote antitumor immunity specifically via natural killer (NK)-cell mediated antibody-dependent cell-mediated cytotoxicity (ADCC), which is also an important mechanism of action of cetuximab. The goal of our work is to determine how modulation of the IL-1 pathway affects HNSCC tumor response to cetuximab. We found that blockade of IL-1 signaling using an IL-1-receptor antagonist (IL-1RA, anakinra), neutralizing IL-1α/IL-1β antibodies, and genetic knockdown of the IL-1R all suppressed the anti-tumor efficacy of cetuximab, while IL-1α overexpression and treatment with recombinant IL-1α enhanced HNSCC tumor response to cetuximab in immunodeficient and immunocompetent HNSCC mouse models. Mechanistically, these results appear to be due to modulation of ADCC, as we found that IL-1 blockade significantly reduced cetuximab-mediated ADCC in vitro. Additionally, we found that HNSCC patients with high baseline circulating levels of IL-1 ligands (IL-1α, IL-1β) were significantly more likely to respond favorably to cetuximab monotherapy compared to patients with low or no baseline circulating IL-1 ligands. Altogether, these results suggest that IL-1 signaling is necessary for HNSCC tumor response to cetuximab. Therefore, IL-1α warrants further study as a novel therapeutic to enhance response to cetuximab and as an immunologic biomarker for cetuximab response. Citation Format: Madelyn M. Espinosa-Cotton, Rachel A. Dahl, Elana Fertig, Isaac Jensen, Ayana J. McLaren, Kenley Miller, Samuel N. Rodman, Sandra Schmitz, Andrean L. Simons. Interleukin-1 signaling is required for HNSCC tumor response to cetuximab [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5734.