ChIP-seq analysis of H4K12Ac antibody binding in hTert-HME1 cells treated with either control or BRCA2 siRNAs

Individuals with a single functional copy of the BRCA2 tumor suppressor have elevated risks for breast, ovarian and other solid tumor malignancies. The exact mechanisms of carcinogenesis due to BRCA2 haploinsufficiency remain unclear, but one possibility is that at-risk cells are subject to acute periods of decreased BRCA2 availability and function (“BRCA2-crisis”), which may contribute to disease. Here we establish an in vitro model for BRCA2-crisis that demonstrates novel epigenetic remodeling and activation of an NF-?B survival pathway in response to transient BRCA2-depletion. Mechanistically, we identify BRCA2 chromatin binding, histone acetylation and associated transcriptional activity as critical determinants of the epigenetic response to BRCA2-crisis. These epigenetic alterations are reflected in transcriptional profiles of pre-malignant tissues from BRCA2-carriers and therefore may reflect natural steps in human disease. By modeling BRCA2-crisis in vitro we have derived insights into pre-neoplastic molecular alterations that may enhance the development of preventative therapies. Overall design: 2 replicates of siControl, 2 replicates of siBRCA2, 1 siControl input, 1 siBRCA2 input. hTert-HME1 cell line was transfected with siRNA, passaged for 12 days to undergo BRCA2 crisis and recovery then cells were cross linked with 1% formaldehyde and processed for ChIP-seq. Diffbind was used to identify differentially increased peaks in siBRCA2 condition versus siControl condition.