Abstract 3085: Epithelial S100A2 reduced upper aerodigestive track carcinogenesis by immunomodulation

Abstract

Abstract Upper aerodigestive track cancer (UATC) including oral and esophageal cancer is the 3rd leading cause of cancer death in the world. Most of these patients demonstrate compromised immunity systems. Myeloid-derived suppressor cells (MDSCs), a population of cells exerting immunosuppressive effects, can sustain cancer progression by providing a pro-tumor microenvironment through the enhancement of T-cell suppressive factors like arginase 1 (ARG1). MDSCs can subsequently facilitate the development of immunosuppressive regulatory T cells (Tregs). Tumor-associated macrophages (TAMs) produce multiple inflammation modulators and are other key players in tumor microenvironment and divided into M1 and M2 phenotypes with specific expression of different cytokines in each type. Several S100 proteins are recently shown to participate in tumor promotion or suppression through both autocrine and least known receptor-mediated paracrine release. RAGE and TLR4, frequently expressed on immune cells, are two known receptors for S100 proteins. Among many S100 proteins, we previously showed a tumor suppressor role of S100A2 in oral cancer. Whether S100A2 functions as a tumor suppressor in mice and plays any role in regulating these immune cell populations during upper aerodigestive track carcinogenesis remains elusive. Due to lack of S100A2 expression in mice, epithelial-specific human S100A2 transgenic mice and their wildtype littermates were used for tumor induction in upper areodigestive track by the co-treatment of 4NQO and arecoline. Epithelial S100A2 significantly repressed tumor formation in esophagus. To understand the involvement of immune cell recruitment in these mice, flow cytometry and qRT-PCR analyses were used. Among the key molecules associated with MDSCs, Tregs and TAMs, S100A2 preferentially induced tumor macrophage polarization to M1 phenotype with a marginal decrease of Tregs recruitment at 7 month post tumor induction. Together, epithelial S100A2 exerts anti-tumor effect in part through differential impact on immune cell recruitment although more studies are needed to underscore the action mechanism. Citation Format: Li-Wha Wu. Epithelial S100A2 reduced upper aerodigestive track carcinogenesis by immunomodulation [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 3085.