Abstract 5162: Id1 is an oncogenic target of RNA binding protein HuR in gastric cancer

Hu antigen R (HuR), a ubiquitous RNA-binding protein (RBP), has been shown to be overexpressed in gastric cancer. Cytoplasmic HuR is reported to be associated with high stage, distant metastases and unresectability. HuR efficiently regulates cancer-related gene expression by binding to AU- and U-rich sequences (ARE) in the 3’ and 5’-untranslated region (UTR) of mRNAs. Id1 (Inhibitor of DNA binding) is a putative oncogene that we previously found was upregulated in gastric cancer and associated with poor prognosis. Id1 mRNA contains several putative HuR ARE sites. Our goal is to determine the impact of HuR on Id1 expression. We first confirmed Id1 is a HuR target by Ribonucleoprotein Immunoprecipitation (RNP-IP) in gastric cancer cells. Then, we found KH-3, a potent and specific inhibitor of HuR, inhibited Id1 mRNA and protein expression. The proliferative and invasive capabilities of the gastric cancer cells were also inhibited by KH-3. We conclude that Id1 is a target of RNA-binding protein HuR in gastric cancer. HuR specific inhibitor, KH-3, may be a promising therapeutic agent in treating HuR/Id1 high gastric cancers. Citation Format: Shuang Han, Xiaoqing Wu, Yuxiao Guo, Jing Zhang, Xuan Gu, Rebecca T. Marquez, Jeffrey Aube, Liang Xu. Id1 is an oncogenic target of RNA binding protein HuR in gastric cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 5162.