The paradox of histone deacetylase inhibitor-mediated modulation of cellular responses to radiation

Cell Cycle. 2006 Feb;5(3):288-95. doi: 10.4161/cc.5.3.2421. Epub 2006 Feb 17.


Given the widespread use of radiotherapy in cancer, there has been a longstanding interest in the development of chemical compounds that can modify cellular responses to ionizing radiation. Additionally, recent terrorism threats suggesting attacks with 'dirty bombs' containing combinations of radioactive isotopes with conventional explosives, has increased the interest in compounds that can protect from radiation injury. Histone deacetylase inhibitors represent a new class of compounds that can modulate the effects of radiation. Research with histone deacetylase inhibitors has largely focussed on the consequences of their ability to alter gene transcription via histone acetylation and on their properties as anti-cancer agents. They have been shown to cause cell cycle and growth arrest, differentiation and in certain cases apoptosis in cell cultures and in vivo. In addition to their intrinsic anti-cancer properties, numerous studies have demonstrated that histone deacetylase inhibitors can modulate cellular responses to other toxicity-inducing modalities including ionizing radiation. The consensus is that histone deacetylase inhibitors markedly enhance the sensitivity of cells to radiation by altering numerous molecular pathways. Intriguingly, a report has also shown that histone deacetylase inhibitors can reduce radiation induced acute and late skin damage using a well-established animal model of cutaneous radiation syndrome. Hence, there is an emerging interest in potential use of histone deacetylase inhibitors as radiation sensitizers or protectors. This review focuses on the different mechanisms by which histone deacetylase inhibitors modify cellular responses to ionizing radiation.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Animals
  • Antineoplastic Agents / pharmacology*
  • Antineoplastic Agents / therapeutic use
  • Apoptosis / drug effects
  • Apoptosis / radiation effects
  • Cell Differentiation / drug effects
  • Cell Differentiation / radiation effects
  • Cell Proliferation / drug effects
  • Cell Proliferation / radiation effects
  • Clinical Trials as Topic
  • Combined Modality Therapy
  • Drug Evaluation, Preclinical
  • Enzyme Inhibitors / pharmacology
  • Enzyme Inhibitors / therapeutic use
  • Histone Deacetylase Inhibitors*
  • Humans
  • Models, Biological
  • Neoplasms / metabolism*
  • Neoplasms / pathology
  • Neoplasms / therapy
  • Radiation-Protective Agents / pharmacology*
  • Radiation-Protective Agents / therapeutic use
  • Radiation-Sensitizing Agents / pharmacology*
  • Radiation-Sensitizing Agents / therapeutic use


  • Antineoplastic Agents
  • Enzyme Inhibitors
  • Histone Deacetylase Inhibitors
  • Radiation-Protective Agents
  • Radiation-Sensitizing Agents