High Potency of a Novel Resveratrol Derivative, 3,3′,4,4′-Tetrahydroxy-trans-stilbene, against Ovarian Cancer Is Associated with an Oxidative Stress-Mediated Imbalance between DNA Damage Accumulation and Repair

Figure 4

Effect of RVT and 3,3′,4,4′-THS on the concentration of 8-OH-dG ((a)–(c)), efficiency of 8-OH-dG repair ((d)–(f)), and expression of DNA glycosylase I (hOgg1) mRNA ((g)–(j)) in ovarian cancer cells. The magnitude of oxidative DNA damage was assessed upon 24-h cell exposure to stilbenes using a commercially available kit. The asterisks indicate a significant difference as compared to the control group (Con). The hashes indicate a significant difference as compared to cells subjected to RVT. The experiments were performed in hexaplicate ((a)–(c)). The efficiency of DNA repair ((d)–(f)) was evaluated in cells in which DNA injury was generated in response to 24-h incubation with resveratrol (RVT) and 3,3′,4,4′-THS (3,3′,4,4′). Afterwards, the cells were washed and exposed to standard growth medium for the next 24 h to recover. The magnitude of DNA damage was evaluated in three points: before exposure to the stilbenes (−24 h), after 24-h exposure (time 0), and after a 24-h period of recovery (+24 h). The asterisks indicate a significant difference as compared to cells not exposed to stilbenes (control group; −24 h point). The hashes indicate a significant difference as compared to cells preincubated with RVT (time-point 0). The experiments were performed in hexaplicate. Results shown in panel (g)–(i) represent the effect of resveratrol (RVT) and 3,3′,4,4′-THS (3,3′,4,4′) on the expression of DNA glycosylase I (hOgg1) mRNA. The asterisks indicate a significant difference as compared to cells exposed to RVT. The hashes indicate a significant difference as compared to cells preincubated with stilbenes for 24 h to generate DNA injury (time-point 0). The experiments were performed in hexaplicate. A representative RT-PCR analysis of the hOgg1 mRNA level in A2780 cells subjected to resveratrol (RVT) and 3,3′,4,4′-THS (j).