Abstract 3939: Delineation of the ATM-Snail pathway in the DNA damage response

Abstract To cope with constant challenges toward the fidelity of genome by DNA damaging insults (both endogenous and exogenous), activation of the DNA damage response (DDR) is an essential step in preventing genomic instability. Studies of mammalian mechanisms have revealed that there are comprehensive, coordinated pathways that, when activated, serve to regulate the DDR. Recently, we have shown that hyperactive DDR mediated by the Ataxia-Telangiectasia Mutated (ATM) kinase is linked to activation of the Zinc finger protein SNAI1 (Snail). Activated Snail in metastasis is well-characterized by its role as transcriptional repressor of E-cadherin thereby inducing an epithelial-to-mesenchymal transition (EMT). Here we report that, in response to DNA damage, activation of the ATM-Snail pathway, mediated by Snail Serine 100 phosphorylation, also contributes to the regulation of the cellular sensitivity to ionizing radiation. Expression of a hyperactive Snail led to radioresistance. More interestingly, the Serine 100 to Glutamic Acid mutant variant of Snail displayed an enhanced invasion index after low dose radiation, independent of survival. Functional genomics and proteomics studies revealed downstream targets and interacting partners of Snail in the DDR. Together, we highlight the functional significance of the ATM-Snail pathway in the DDR. Citation Format: Rebecca J. Boohaker, Joshua Fried, Xiaoli Cui, Bo Xu. Delineation of the ATM-Snail pathway in the DNA damage response. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3939. doi:10.1158/1538-7445.AM2014-3939