Gene Amplification Associated Overexpression of the RNA Editing Enzyme ADAR1 Enhances Human Lung Tumorigenesis

The introduction of new therapies against particular genetic mutations in non-small cell lung cancer is a promising avenue for improving the survival of these patients, but the target population is small. There is a need to uncover new potential actionable genetic lesions and non-conventional cancer pathways, such as RNA editing, are worthy to explore. Herein we show that the adenosine-to-inosine 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 mice models, whereas its overexpression causes 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, show poor outcome. Overall, our results indicate a role for ADAR1 as a lung cancer oncogene undergoing gene amplification-associated activation that affect downstream RNA editing patterns and patient prognosis. 5 Cell lines were hybridized on the Infinium Human Omni5 Beadarray.