Histone deacetylase inhibitors activate NF-kappaB in human leukemia cells through an ATM/NEMO-related pathway

J Biol Chem. 2010 Mar 26;285(13):10064-10077. doi: 10.1074/jbc.M109.095208. Epub 2010 Jan 11.

Abstract

Mechanisms underlying histone deacetylase inhibitor (HDACI)-mediated NF-kappaB activation were investigated in human leukemia cells. Exposure of U937 and other leukemia cells to LBH-589 induced reactive oxygen species (ROS) followed by single strand (XRCC1) and double strand (gamma-H2AX) DNA breaks. Notably, LBH-589 lethality was markedly attenuated by small interfering RNA (siRNA) knockdown of the DNA damage-linked histone, H1.2. LBH-589 triggered p65/RelA activation, NF-kappaB-dependent induction of Mn-SOD2, and ROS elimination. Interference with LBH-589-mediated NF-kappaB activation (e.g. in I kappaB alpha super-repressor transfected cells) diminished HDACI-mediated Mn-SOD2 induction and increased ROS accumulation, DNA damage, and apoptosis. The Mn-SOD2 mimetic TBAP (manganese(III)-tetrakis 4-benzoic acid porphyrin) prevented HDACI-induced ROS and NF-kappaB activation while dramatically attenuating DNA damage and cell death. In contrast, TRAF2 siRNA knockdown, targeting receptor-mediated NF-kappaB activation, blocked TNFalpha- but not HDACI-mediated NF-kappaB activation and lethality. Consistent with ROS-mediated DNA damage, LBH-589 exposure activated ATM (on serine 1981) and increased its association with NEMO. Significantly, siRNA NEMO or ATM knockdown blocked HDACI-mediated NF-kappaB activation, resulting in diminished MnSOD2 induction and enhanced oxidative DNA damage and cell death. In accord with the recently described DNA damage/ATM/NEMO pathway, SUMOylation site mutant NEMO (K277A or K309A) cells exposed to LBH-589 displayed diminished ATM/NEMO association, NEMO and p65/RelA nuclear localization/activation, and MnSOD2 up-regulation. These events were accompanied by increased ROS production, gamma-H2AX formation, and cell death. Together, these findings indicate that in human leukemia cells, HDACIs activate the cytoprotective NF-kappaB pathway through an ATM/NEMO/SUMOylation-dependent process involving the induction of ROS and DNA damage and suggest that blocking NF-kappaB activation via the atypical ATM/NEMO nuclear pathway can enhance HDACI antileukemic activity.

Publication types

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

MeSH terms

  • Ataxia Telangiectasia Mutated Proteins
  • Cell Cycle Proteins / metabolism
  • Cell Line, Tumor
  • DNA-Binding Proteins / metabolism
  • Enzyme Activation
  • Gene Expression Regulation, Enzymologic*
  • Gene Expression Regulation, Leukemic*
  • HL-60 Cells
  • Histone Deacetylase Inhibitors / metabolism*
  • Humans
  • I-kappa B Kinase / metabolism
  • Jurkat Cells
  • Leukemia / drug therapy*
  • Leukemia / enzymology*
  • Mutation
  • NF-kappa B / metabolism*
  • Protein Serine-Threonine Kinases / metabolism
  • Reactive Oxygen Species
  • SUMO-1 Protein / metabolism
  • Tumor Suppressor Proteins / metabolism
  • U937 Cells

Substances

  • Cell Cycle Proteins
  • DNA-Binding Proteins
  • Histone Deacetylase Inhibitors
  • IKBKG protein, human
  • NF-kappa B
  • Reactive Oxygen Species
  • SUMO-1 Protein
  • SUMO1 protein, human
  • Tumor Suppressor Proteins
  • ATM protein, human
  • Ataxia Telangiectasia Mutated Proteins
  • Protein Serine-Threonine Kinases
  • I-kappa B Kinase