Abstract 4471: Pax9 regulates squamous cell differentiation and alcohol-associated carcinogenesis in the oro-esophageal epithelium

Abstract

Pax9 is a transcription factor of the Pax family characterized by a DNA-binding paired domain. Previous studies have suggested a potential role of Pax9 in squamous cell differentiation and carcinogenesis of oro-esophageal epithelium. However, its functional role in differentiation and carcinogenesis remains unclear. In this study, Pax9 deficiency in mouse esophagus promoted cell proliferation, delayed cell differentiation and altered the global gene expression profile. Ethanol exposure down-regulated Pax9 expression in human esophageal epithelial cells in vitro and mouse forestomach and tongue in vivo. We further showed that PAX9 was down-regulated in human oro-esophageal squamous cell carcinoma (OESCC), and its down-regulation was associated with alcohol drinking and promoter hypermethylation. Moreover, ad libitum feeding with an isocaloric Lieber-DeCarli liquid diet containing ethanol for 40 weeks or Pax9 deficiency promoted NMBA-induced squamous cell carcinogenesis in mouse tongue, esophagus, and forestomach. In conclusion, Pax9 regulates squamous cell differentiation in the oro-esophageal epithelium. Alcohol drinking and promoter hypermethylation are associated with PAX9 silencing in human OESCC. Pax9 down-regulation, at least in part, contributes to alcohol-associated oro-esophageal squamous cell carcinogenesis. Citation Format: Zhaohui Xiong, Shuang Ren, Hao Chen, Yao Liu, Caizhi Huang, Yawan Lyvia Zhang, Joab Otieno Odera, Tong Chen, Ralf Kist, Heiko Peters, Katherine Garman, Zheng Sun, Xiaoxin Luke Chen. Pax9 regulates squamous cell differentiation and alcohol-associated carcinogenesis in the oro-esophageal epithelium [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 4471.