Abstract 2506: Smarca4 inactivation promotes lineage-specific transformation and early metastatic features in the lung

Abstract

Abstract SMARCA4 (BRG1) encodes for one of two mutually-exclusive ATPases present in SWI/SNF chromatin remodeling complexes, and is among the most frequently mutated genes in human lung adenocarcinoma. Despite its prevalence, the functional consequences of SMARCA4 alterations on lung cancer initiation and progression remain poorly understood. Using genetically engineered mouse models, patient-derived xenografts, and single-cell epigenomic profiling, we demonstrate that loss of Smarca4 sensitizes CCSP+ cells within the lung to malignant transformation and tumor progression, resulting in highly advanced dedifferentiated tumors and increased metastatic incidence. Consistent with these phenotypes, Smarca4-deficient tumors lack lung lineage transcription factor activities and instead show activation of embryonic stem cell-like programs, resembling a metastatic cell state. Thus, the SWI/SNF complex - via Smarca4 - acts as a gatekeeper for lineage-specific cellular transformation and metastasis during lung cancer evolution. Citation Format: Carla P. Concepcion, Sai Ma, Lindsay M. LaFave, Arjun Bhutkar, Manyuan Liu, Lydia P. DeAngelo, Jonathan Y. Kim, Isabella Del Priore, Adam J. Schoenfeld, Vinay K. Kartha, Peter M. Westcott, Francisco J. Sánchez-Rivera, Kevin Meli, Manav Gupta, Gregory J. Riely, Natasha Rekhtman, Charles M. Rudin, Carla F. Kim, Aviv Regev, Jason D. Buenrostro, Tyler Jacks. Smarca4 inactivation promotes lineage-specific transformation and early metastatic features in the lung [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2506.