Large-Scale Topological Changes Restrain Malignant Progression in Colorectal Cancer

Cell. 2020 Sep 17;182(6):1474-1489.e23. doi: 10.1016/j.cell.2020.07.030. Epub 2020 Aug 24.

Abstract

Widespread changes to DNA methylation and chromatin are well documented in cancer, but the fate of higher-order chromosomal structure remains obscure. Here we integrated topological maps for colon tumors and normal colons with epigenetic, transcriptional, and imaging data to characterize alterations to chromatin loops, topologically associated domains, and large-scale compartments. We found that spatial partitioning of the open and closed genome compartments is profoundly compromised in tumors. This reorganization is accompanied by compartment-specific hypomethylation and chromatin changes. Additionally, we identify a compartment at the interface between the canonical A and B compartments that is reorganized in tumors. Remarkably, similar shifts were evident in non-malignant cells that have accumulated excess divisions. Our analyses suggest that these topological changes repress stemness and invasion programs while inducing anti-tumor immunity genes and may therefore restrain malignant progression. Our findings call into question the conventional view that tumor-associated epigenomic alterations are primarily oncogenic.

Keywords: DNA methylation; chromatin; colon cancer; compartment; epigenetics; genome topology; nuclear architecture.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Division
  • Cellular Senescence / genetics
  • Chromatin / metabolism*
  • Chromatin Immunoprecipitation Sequencing
  • Chromosomes / genetics
  • Chromosomes / metabolism*
  • Cohort Studies
  • Colorectal Neoplasms / genetics*
  • Colorectal Neoplasms / metabolism*
  • Colorectal Neoplasms / mortality
  • Colorectal Neoplasms / pathology
  • Computational Biology
  • DNA Methylation* / genetics
  • Epigenesis, Genetic*
  • Epigenomics
  • Gene Expression Regulation, Neoplastic / genetics*
  • HCT116 Cells
  • Humans
  • In Situ Hybridization, Fluorescence
  • Microscopy, Electron, Transmission
  • Molecular Dynamics Simulation
  • RNA-Seq
  • Spatial Analysis
  • Tumor Suppressor Proteins / genetics
  • Tumor Suppressor Proteins / metabolism

Substances

  • Chromatin
  • Tumor Suppressor Proteins