Valproic Acid-Mediated Reduction of DNA Double-Strand Break Reparation Capacity of Irradiated MCF-7 Cells

Document Type: Original Paper

Authors

1 Biochemistry and Metabolic Disorders Research Center, Golestan University of Medical Sciences, Gorgan, Iran

2 Biochemistry and biophysics dept of Golestan university of medical sciences.Faculty of Medicine, Golestan University of Medical Sciences.Begin of Shast colah road.Gorgan .Iran

3 Laboratory Sciences Research Center, Golestan University of Medical Sciences, Gorgan, Iran

Abstract

Introduction
H istone deacetylase inhibitors (HDIs), as  radiation sensitizing agents, are considered as a novel class of anti-cancer factors, which are studied in various tumor cell-lines. Valproic acid (VPA) is an HDI, which is effectively used in the treatment of epilepsy, migraines, and some particular types of depression. In this study, we evaluated the effects of VPA and ionizing radiation separately, as well as combined, with the alterations of histone H2AX phosphorylation (γH2AX) at Ser139, a marker of DNA damage and its repair, on MCF-7 breast cancer cell line.
Materials and Methods
Three groups of cells were selected, including 1) pretreated with VPA for 48 h followed by irradiation, 2) VPA only, and 3) irradiation only. The levels of γH2AX expression were evaluated using Western blot.
Results
The results of our study showed that VPA signifi‌cantly enhanced the expression of γH2AX, when applied 48 h prior to irradiation compared to the IR or VPA only treated cells. We also concluded that VPA pre-treatment delayed γH2AX dephosphorylation and dispersal for up to 12 h after irradiation, while γH2AX dephosphorylation disappeared in just 2 h when using irradiation alone and without VPA pre-treatment.
Conclusion
Our findings are consistent with the general consensus that VPA efficiently sensitizes cancer cells to the effects of ionizing radiation and prevents DNA double-strand break repair, which leads to enhanced breast cancer cell death.

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Volume 13, Issue 4
November and December 2016
Pages 289-295
  • Receive Date: 20 August 2016
  • Revise Date: 11 September 2016
  • Accept Date: 13 November 2016