The introduction of new therapies against particular genetic mutations in non-small-cell lung cancer is a promising avenue for improving patient survival, but the target population is small. There is a need to discover new potential actionable genetic lesions, to which end, non-conventional cancer pathways, such as RNA editing, are worth exploring. Herein we show that the adenosine-toinosine editing enzyme ADAR1 undergoes gene amplification in non-small cancer cell lines and primary tumors in association with higher levels of the corresponding mRNA and protein. From a growth and invasion standpoint, the depletion of ADAR1 expression in amplified cells reduces their tumorigenic potential in cell culture and mouse models, whereas its overexpression has the opposite effects. From a functional perspective, ADAR1 overexpression enhances the editing frequencies of target transcripts such as NEIL1 and miR-381. In the clinical setting, patients with early-stage lung cancer, but harboring ADAR1 gene amplification, have poor outcomes. Overall, our results indicate a role for ADAR1 as a lung cancer oncogene undergoing gene amplification-associated
activation that affects downstream RNA editing patterns and patient prognosis.This work was supported by the European Research Council under the European Community's Seventh Framework Programme (FP7/2007-2013)/ERC grant agreement no. 268626—EPINORC project, the Grant agreement number HEALTH-F2-2010-258677—CURELUNG project, the Spanish Ministry of Economy and Competitiveness (MINECO Projects no. SAF2011-22803, PI13-01339 and SAF2014-55000- R), the Institute of Health Carlos III (ISCIII)—PI10/02992, Ministerio de Educación, Ciencia e Innovación Grant SAF2010-14935, the Cellex Foundation, the National Cancer Center Research and Development Fund (NCC Biobank: 23 A-1) and the Health and Science Departments of the Catalan Government (Generalitat de Catalunya) AGAUR—project no. 2009SGR1315 and 2014SGR633.Peer Reviewe
