The Effect of Resveratrol on mRNA Levels of DNA polymerase Beta and Oxidative DNA Damage In H2O2-Induced Human Colon Cancer HT-29 Cells

The Effect of Resveratrol on mRNA levels of DNA polymerase beta and oxidative DNA damage in H2O2-induced human colon cancer HT-29 cells Farzane Sadat Shahrokhi1, Maryam Baazm2, Mohammad Taghi Goodarzi3, Ebrahim Eftekhar4, Farideh Jalali Mashayekhi1, 1 Department of Biochemistry and Genetics, School of Medicine, Arak University of Medical Sciences, Arak, Iran. 2 Department of Anatomy, School of Medicine, Arak University of Medical Sciences, Arak, Iran. 3Research Center for Molecular Medicine, Hamadan University of Medical Sciences, Hamadan, Iran. 4Molecular Medicine Research Center, Department of Biochemistry, School of Medicine, Hormozgan University of Medical Sciences, Bandar Abbas, Iran. 5Molecular and Medicine Research Center, Arak University of Medical Sciences, Arak, Iran. Introduction: Resveratrol (3,4,5-trihydroxystilbene), a polyphenol found in high levels in grape skin, has recently attracted huge attention because of its anti-carcinogenic properties. Protective effects of resveratrol against oxidative damage in DNA may be due to its ability to stimulate DNA repair pathways such as the base excision repair (BER). Methods: This study aimed to investigate the effect of resveratrol on gene expression of DNA polymerase beta (DNA pol β), the primary polymerase involved in BER, in H2O2-inducedoxidative human colon cancer HT-29 cells. The 8-oxo-7,8-dihydro-2’-deoxyguanosine (8-OHdG) level and mRNA expression level of DNA polymerase beta (pol β) was measured after human colon cancer HT-29 cells were treated with 100 μM H2O2for 30 min followed by exposure with 75 µM of resveratrol for 48 h. Results: The level of 8-OHdG was significantly increased by H2O2 treatment, but resveratrol pretreatment of cells prior to H2O2 treatment led to a significant reduction of 8-OHdG to the levels similar to those observed in controls. Analysis of qRT -PCR data by one way ANOVA revealed that resveratrol pretreatment also caused a measurable increase in the mRNA expression of DNA polymerase beta (DNA pol β) comparing to that of H2O2-treated and control cells. Conclusion: The cancer-preventive effects of resveratrol may be due in part to stimulation of base excision repair processes. Our data confirm that resveratrol exerts its anti-oxidant and scavenging properties through a reduction in 8-OHdG level. Keywords: DNA repair enzymes, DNA polymerase beta, DNA damage, Hydrogen peroxide, Resveratrol