Page 150 - 2014 Printable Abstract Book
P. 150
Supported by “Dark.Risk” project. This project is financially supported by the 7th Framework programme
of the European Commission (Grant agreement n°: 323216).
(PS2-25) Combined radiation injury causes long-lasting alterations in histone deacetylase 1 (HDAC1).
Brenda J. Curtis, PhD; Jessica L. Palmer, M.S.; Luis Ramirez, BS; Stewart R. Carter, MD; and Elizabeth J.
Kovacs, PhD, Loyola University Chicago, Maywood, IL
In nuclear catastrophes, severe radiation injuries occur in conjunction with other trauma,
including burn, in up to 70% of cases. Compared to patients with isolated injuries, those with combined
radiation injury (CRI) have more complications, including the development of pulmonary fibrosis, and
increased morbidity and mortality. The lungs are particularly sensitive to both acute lung injury from burn
and are also highly radio-sensitive, due to the over-exuberant production of pro-inflammatory mediators.
Radiation pneumonitis is characterized by cyclical waves of inflammation. One mechanism to explain this
cyclical pattern is altered epigenetic regulation. To explore this possibility, C57BL/6 mice were divided into
5-5.5 Gray (Gy) total body irradiation, 15% total body surface area scald burn, radiation followed by burn
(CRI), or sham controls. Preliminary studies provide supporting evidence for altered pulmonary HDACs
following burn, radiation, and CRI. Specifically, 24 hours after insult, pulmonary HDAC1 levels were
increased two fold in lung whole cell lysates from burned mice (p<0.05). Immunohistochemistry
confirmed elevated HDAC1 levels and also demonstrated increased HDAC1 phosphorylation. Global and
specific changes in lysine acetylation in purified histones was also observed (p<0.05). Radiation alone has
minimal effects on HDAC1 at this time-point. However, one week post-injury, HDAC1 levels were
normalized in mice exposed to isolated burn or radiation injury, but were two fold higher in CRI (p<0.05).
In contrast, one month after injury, mice exposed to radiation alone and those with CRI, had three fold
higher levels of HDAC1, demonstrating lasting effects of radiation and CRI on HDAC1. Ongoing research in
our laboratory is investigating the therapeutic potential of HDAC inhibitors in attenuating pulmonary
complications including early inflammatory responses to CRI. Research was supported by the Falk
Foundation and by NIH R21/R33 AI080528 (EJK).
(PS2-26) Inhibition of DNMT1 radiosensitizes and perturbs cell cycle regulators in breast cancer. Morgan
E. Laney, BS; Deborah A. Antwih, BS; Steven P. Zielske, PhD, Wayne State University, Detroit, MI
Abstract.Abstract1:
DNA methyltransferase 1 (DNMT1) is the main enzyme responsible for methylating newly synthesized
DNA and has been shown to be associated with DNA repair and DNA replication machinery. DNMT1
inhibitors such as 5-azacytidine (5AC) induce degradation of DNMT1 and can alter the cell response to
radiation. In this study, we investigated the effect of DNMT inhibitors on cell cycle regulators in breast
cancer, both with and without exposure to radiation.
We first determined the effect of DNMT inhibitors on radiation sensitivity of SUM-159 and MDA-MB-231
cells using a clonogenic assay. Treatment with 5AC and zebularine resulted in radiosensitization with
enhancement factors of 1.5 and 1.3, respectively. DNMT1 protein was degraded and DNA methylation
levels were reduced. We then treated cells with 5AC alone, radiation alone, or combination 5AC plus
radiation, and analyzed cell cycle regulators. In SUM-159 cells, Chk1 was phosphorylated in response to
148 | P a g e
of the European Commission (Grant agreement n°: 323216).
(PS2-25) Combined radiation injury causes long-lasting alterations in histone deacetylase 1 (HDAC1).
Brenda J. Curtis, PhD; Jessica L. Palmer, M.S.; Luis Ramirez, BS; Stewart R. Carter, MD; and Elizabeth J.
Kovacs, PhD, Loyola University Chicago, Maywood, IL
In nuclear catastrophes, severe radiation injuries occur in conjunction with other trauma,
including burn, in up to 70% of cases. Compared to patients with isolated injuries, those with combined
radiation injury (CRI) have more complications, including the development of pulmonary fibrosis, and
increased morbidity and mortality. The lungs are particularly sensitive to both acute lung injury from burn
and are also highly radio-sensitive, due to the over-exuberant production of pro-inflammatory mediators.
Radiation pneumonitis is characterized by cyclical waves of inflammation. One mechanism to explain this
cyclical pattern is altered epigenetic regulation. To explore this possibility, C57BL/6 mice were divided into
5-5.5 Gray (Gy) total body irradiation, 15% total body surface area scald burn, radiation followed by burn
(CRI), or sham controls. Preliminary studies provide supporting evidence for altered pulmonary HDACs
following burn, radiation, and CRI. Specifically, 24 hours after insult, pulmonary HDAC1 levels were
increased two fold in lung whole cell lysates from burned mice (p<0.05). Immunohistochemistry
confirmed elevated HDAC1 levels and also demonstrated increased HDAC1 phosphorylation. Global and
specific changes in lysine acetylation in purified histones was also observed (p<0.05). Radiation alone has
minimal effects on HDAC1 at this time-point. However, one week post-injury, HDAC1 levels were
normalized in mice exposed to isolated burn or radiation injury, but were two fold higher in CRI (p<0.05).
In contrast, one month after injury, mice exposed to radiation alone and those with CRI, had three fold
higher levels of HDAC1, demonstrating lasting effects of radiation and CRI on HDAC1. Ongoing research in
our laboratory is investigating the therapeutic potential of HDAC inhibitors in attenuating pulmonary
complications including early inflammatory responses to CRI. Research was supported by the Falk
Foundation and by NIH R21/R33 AI080528 (EJK).
(PS2-26) Inhibition of DNMT1 radiosensitizes and perturbs cell cycle regulators in breast cancer. Morgan
E. Laney, BS; Deborah A. Antwih, BS; Steven P. Zielske, PhD, Wayne State University, Detroit, MI
Abstract.Abstract1:
DNA methyltransferase 1 (DNMT1) is the main enzyme responsible for methylating newly synthesized
DNA and has been shown to be associated with DNA repair and DNA replication machinery. DNMT1
inhibitors such as 5-azacytidine (5AC) induce degradation of DNMT1 and can alter the cell response to
radiation. In this study, we investigated the effect of DNMT inhibitors on cell cycle regulators in breast
cancer, both with and without exposure to radiation.
We first determined the effect of DNMT inhibitors on radiation sensitivity of SUM-159 and MDA-MB-231
cells using a clonogenic assay. Treatment with 5AC and zebularine resulted in radiosensitization with
enhancement factors of 1.5 and 1.3, respectively. DNMT1 protein was degraded and DNA methylation
levels were reduced. We then treated cells with 5AC alone, radiation alone, or combination 5AC plus
radiation, and analyzed cell cycle regulators. In SUM-159 cells, Chk1 was phosphorylated in response to
148 | P a g e
