Abstract PR14: Nucleation of transcriptional super-enhancers at tumor oncogenes

Abstract

Abstract Transcriptional super-enhancers drive expression of oncogenes in many cancers and are being targeted with novel transcriptional and epigenetic therapeutics (1,2,3,4). Super-enhancers are acquired in cancers through multiple mechanisms, including DNA translocation of an extant super-enhancer and focal amplification. We recently discovered a novel mechanism by which super-enhancers are nucleated in T cell acute lymphoblastic leukemias (T-ALLs) (5). In this case, a small, monoallelic insertion creates a DNA binding site for a master transcription factor protein, which binds and recruits additional factors to nucleate the super-enhancer, which in turn drives high levels of the TAL1 transcription factor. We describe here a method for unbiased identification of similar genomic insertions that nucleate potentially oncogenic regulatory elements in cancers. This approach uses data from genome-wide ChIP-Seq studies that map locations of enhancer-binding proteins to identify sequences missing from reference genomes. We have found many additional genomic insertions in many additional cancers. I will describe new insights into the regulation of cancer that occur due to nucleation of novel regulatory elements. 1 Hnisz, Abraham, Lee, et al., Cell 2013 2 Loven, Hoke, Lin, et al., Cell 2013 3 Kwiatkowski, et al., Nature, 2014 4 Chipumoro, et al., Cell, 2014 5 Mansour et al., Science 2014 Citation Format: Brian J. Abraham, Nicholas Kwiatkowski, Abraham S. Weintraub, Denes Hnisz, Nancy Hannett, Richard A. Young. Nucleation of transcriptional super-enhancers at tumor oncogenes. [abstract]. In: Proceedings of the AACR Special Conference on Translation of the Cancer Genome; Feb 7-9, 2015; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2015;75(22 Suppl 1):Abstract nr PR14.