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How radiation affects DNA is a hot topic at Oakland University

Thursday, December 5, 2013
How radiation affects DNA is a hot topic at Oakland University
An important question in medicine is how X-rays and other ionizing radiation interact with biological tissue, and particularly with our DNA molecules that hold all our genetic information. Oakland University has two teams working on this problem, and both have recently published articles describing recent advances.

Distinguished Professor Michael Sevilla, of the Department of Chemistry, has been supported (grant number R01CA045424) by the National Cancer Institute, one of the National Institutes of Health, for decades in his study of DNA damage by radiation. He coauthored his recent article with his long-time collaborator, Research Associate Anil Kumar. They published “π vs σ-Radial States of One-Electron-Oxidized DNA/RNA Bases: A Density Functional Theory Study” in the October 3, 2012 issue of the Journal of Physical Chemistry B (Volume 117, Pages 11623-11632). Their article begins

"DNA/RNA base radicals produced by ionizing radiation, UV radiation, OH• and chemical attack have been identified by electron spin resonance (ESR) and pulse radiolysis experiments. The electronic nature of these radicals (σ- or π- type) determines the mechanisms of the development of further DNA damage…. in this present work, we employ density functional theory to calculate the relative stabilities of σ- and π-radicals of one-electron-oxidized DNA bases and their N−H deprotonated neutral radicals and show that for pyrimidine DNA bases the σ- and π- radicals are close in energy and there are conditions for which the σ-radicals become more stable than π-radicals."

A different approach is taken by Eugene Surdutovich of the Department of Physics. His publication, DNA Damage Due to Thermomechanical Effects Caused by Heavy Ions Propagating in Tissue, published in the November 1, 2013 issue of the journal Nuclear Instruments & Methods in Physics Research Section B: Beam Interactions with Materials and Atoms (Volume 314, Pages 63-65) focuses on how ions interact with DNA. Such interactions are important as the use of protons and heavier ions becomes more common in the treatment of cancer. He and his coauthors from the Frankfurt Institute for Advanced Studies write

"The scientific interest in obtaining a deeper understanding of radiation damage is motivated by the development of ion-beam cancer therapy and other application of ions interacting with biological targets. A number of important scientific questions, especially related to DNA damage assessment on the molecular level, have not yet been resolved. Therefore, recently this field has attracted much attention from the scientific community… Among these studies is the multiscale approach to the assessment of radiation damage induced by irradiation with ions. It is aimed at a phenomenon-based quantitative understanding of the scenario from the incidence of an energetic ion on tissue to the cell death. This method combines many spatial, temporal, and energy scales, and is therefore a truly multiscale approach."

These publications indicate that radiation research remains an active field of study here at Oakland University.