BRG1 Loss Predisposes Lung Cancers to Replicative Stress and ATR Dependency
Manav Gupta, Carla P. Concepcion, Caroline G. Fahey, Hasmik Keshishian, Arjun Bhutkar, Christine F. Brainson, Francisco J. Sánchez‐Rivera, Patrizia Pessina, Jonathan Y. Kim, Antoine Simoneau, Margherita Paschini, Mary C. Beytagh, Caroline R. Stanclift, Monica Schenone, D.R. Mani, Chendi Li, Audris Oh, Fei Li, Hai Hu, Angeliki Karatza, Roderick T. Bronson, Alice T. Shaw, Aaron N. Hata, Kwok‐Kin Wong, Lee Zou, Steven A. Carr, Tyler Jacks, Carla F. Kim
Abstract
contribute to lung cancer progression. Using a combination of gain- and loss-of-function approaches, we demonstrate that deletion of BRG1 in lung cancer leads to activation of replication stress responses. Single-molecule assessment of replication fork dynamics in BRG1-deficient cells revealed increased origin firing mediated by the prelicensing protein, CDC6. Quantitative mass spectrometry and coimmunoprecipitation assays showed that BRG1-containing SWI/SNF complexes interact with RPA complexes. Finally, BRG1-deficient lung cancers were sensitive to pharmacologic inhibition of ATR. These findings provide novel mechanistic insight into BRG1-mutant lung cancers and suggest that their dependency on ATR can be leveraged therapeutically and potentially expanded to BRG1-mutant cancers in other tissues. SIGNIFICANCE: These findings indicate that inhibition of ATR is a promising therapy for the 10% of non-small cell lung cancer patients harboring mutations in SMARCA4/BRG1. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/80/18/3841/F1.large.jpg.