GSE210113
BET Inhibitors Target the SCLC-N subtype of Small Cell Lung Cancer by Blocking NEUROD1 Transactivation
Small cell lung cancer can be divided into several molecular subtypes based on the expression of four master transcription factors (ASCL1, NEUROD1, POU2F3, and YAP1). These master factors have not been directly druggable, and we hypothesized that targeting their transcriptional coactivator(s) could provide an alternative approach. Here, we identify that BET bromodomain proteins physically interact with NEUROD1 and function as transcriptional coactivators. Using CRISPR knockout and ChIP-seq, we demonstrate that NEUROD1 plays a critical role in defining the landscapes of BET bromodomain proteins in the SCLC genome. Targeting BET bromodomain proteins by BET inhibitors leads to broad suppression of the NEUROD1-target genes, especially those associated with superenhancers, and reduces SCLC growth in vitro and in vivo. LSAMP, a membrane protein in the IgLON family, was identified as one of the NEUROD1-target genes mediating BET inhibitor sensitivity in SCLC. Altogether, our study reveals that targeting transcriptional coactivators could be a novel approach to blocking the master transcription factors in SCLC for therapeutic purposes. The goal of this experiment was to characterize the genome-wide binding profiles of BET proteins, RPII, and H3K27Ac upon NEUORD1 knockout in H446 cells. Overall design: Chromatin immunoprecipitation DNA-sequencing (ChIP-seq) for NEUROD1, BRD2, BRD3, BRD4, histone H3K27Ac, and RNA polymerase II in H446 NEUROD1-KO cells (#297, cl.2-1) and control cells (NTgRNA cl.10).