Abstract
Abstract The incidence of Barrett's esophagus (BE) and esophageal adenocarcinoma (EAC) has increased dramatically in the past three decades. The development of BE and its progression to EAC is highly correlated with exposure to acidic bile salts due to chronic gastroesophageal reflux disease (GERD). A stimulated overexpression of APE1 has been identified in response to bile acids for oxidative DNA repair and oncogenic signal transduction in BE and EAC, but function and mechanism of APE1 in BE and EAC development remains largely unknown. Here, we demonstrate a new function of APE1 in promoting invasion of dysplastic BE and EAC cells that is dependent on its redox function. We observed aberrant overexpression of APE1 in the cell lines and patients’ samples of dysplastic BE and EAC. In contrast to wild-type APE1, overexpression of redox-defective mutant, C65A, or treatment with APE1-redox-specific inhibitor, E3330, abrogated the pro-invasive phenotype of APE1. Mechanistically, we found that APE1 upregulated protein levels of the key matrix metalloproteinase MMP-14. Knockdown of APE1 decreased MMP-14 protein levels in dysplastic BE and EAC cells. Zymography assays indicated APE1 silencing reduced MMP-14 activity, subsequently impaired MMP-2 activation, and repressed extracellular matrix (ECM) degradation. Further, endocytosis and recycling assays revealed decreased endocytosis/recycling of MMP-14 protein in APE1-knockdown cells. Interestingly, our immunoprecipitation and proximity ligation assay (PLA) revealed a novel interaction between APE1 and ARF6, a key regulator of MMP-14 recycling. This interaction between APE1 and ARF6 activates ARF6 to regulate MMP-14 recycling through APE1-dependent redox function. Conclusion: Our findings demonstrate, for the first time, the role of APE1 redox function in upregulating MMP-14 protein levels through activation of ARF6-mediated MMP-14 recycling. We propose APE1/ARF6/MMP-14 as a novel signaling axis in the invasion and progression of dysplastic BE and EAC. Citation Format: Heng Lu, Ajaz A. Bhat, Dunfa Peng, Zheng Chen, Shoumin Zhu, Jun Hong, Selma Maacha, David Robbins, Abbes Belkhiri, Wael El-Rifai. APE1 upregulates MMP-14 to promote invasion of esophageal adenocarcinoma via redox-sensitive ARF6-mediated recycling [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 157.