Pml nuclear body disruption cooperates in APL pathogenesis and impairs DNA damage repair pathways in mice

Blood. 2018 Feb 8;131(6):636-648. doi: 10.1182/blood-2017-07-794784. Epub 2017 Nov 30.

Abstract

A hallmark of acute promyelocytic leukemia (APL) is altered nuclear architecture, with disruption of promyelocytic leukemia (PML) nuclear bodies (NBs) mediated by the PML-retinoic acid receptor α (RARα) oncoprotein. To address whether this phenomenon plays a role in disease pathogenesis, we generated a knock-in mouse model with NB disruption mediated by 2 point mutations (C62A/C65A) in the Pml RING domain. Although no leukemias developed in PmlC62A/C65A mice, these transgenic mice also expressing RARα linked to a dimerization domain (p50-RARα model) exhibited a doubling in the rate of leukemia, with a reduced latency period. Additionally, we found that response to targeted therapy with all-trans retinoic acid in vivo was dependent on NB integrity. PML-RARα is recognized to be insufficient for development of APL, requiring acquisition of cooperating mutations. We therefore investigated whether NB disruption might be mutagenic. Compared with wild-type cells, primary PmlC62A/C65A cells exhibited increased sister-chromatid exchange and chromosome abnormalities. Moreover, functional assays showed impaired homologous recombination (HR) and nonhomologous end-joining (NHEJ) repair pathways, with defective localization of Brca1 and Rad51 to sites of DNA damage. These data directly demonstrate that Pml NBs are critical for DNA damage responses, and suggest that Pml NB disruption is a central contributor to APL pathogenesis.

Publication types

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

MeSH terms

  • Animals
  • Cell Transformation, Neoplastic / genetics
  • Cell Transformation, Neoplastic / metabolism
  • DNA Damage / genetics
  • DNA End-Joining Repair / genetics
  • DNA Repair / genetics*
  • Intranuclear Inclusion Bodies / genetics
  • Intranuclear Inclusion Bodies / metabolism*
  • Leukemia, Promyelocytic, Acute / genetics*
  • Leukemia, Promyelocytic, Acute / metabolism
  • Leukemia, Promyelocytic, Acute / pathology*
  • Mice
  • Mice, Transgenic
  • Mutagenesis / genetics
  • Oncogene Proteins, Fusion / genetics
  • Oncogene Proteins, Fusion / metabolism
  • Promyelocytic Leukemia Protein / genetics
  • Promyelocytic Leukemia Protein / physiology*
  • Signal Transduction / genetics

Substances

  • Oncogene Proteins, Fusion
  • Pml protein, mouse
  • Promyelocytic Leukemia Protein
  • promyelocytic leukemia-retinoic acid receptor alpha fusion oncoprotein