Mutational synergy coordinately remodels chromatin accessibility, enhancer landscape and 3-Dimensional DNA topology to alter gene expression during leukemia induction (pCHiC)

Altered transcription is a cardinal feature of acute myeloid leukemia (AML), however, exactly how mutations synergise to remodel the epigenetic landscape and rewire 3-Dimensional (3-D) DNA topology is unknown. We have utilized an allelic series of mice carrying the most common mutations in AML, namely Flt3-ITD and Npm1c. These model different “transition states” (normal: wild-type (WT); pre-malignant: single mutant (SM) with either Flt3-ITD or Npm1c; malignant: double mutant (DM)) during AML induction. We have analyzed hematopoietic stem and progenitor cells (HSPCs) from WT and mutant mice for gene expression (RNA-seq), chromatin activation states (ChIP-seq for H3K4me1, H3K4me3, H3K27ac), chromatin accessibility (ATAC-seq), and promoter-anchored 3-D chromatin interaction (promoter capture HiC, pCHiC) and have integrated these analyses to determine the transcriptional, epigenetic and DNA-topological evolution of AML. These findings allow the identification of long-range cis-regulatory circuits, as well as larger and more detailed gene-regulatory networks, whose importance we demonstrate through perturbation of network members. 3-D chromatin interaction was profiled by performing promoter catpure HiC (pCHiC) in WT and mutant HSPCs, as well as in WT neutrophils. Two biological replicates were performed for each cellular state.