Oligonol, a Low Molecular Weight Polyphenol, Enhances Apoptotic Cell Death in Ovarian Cancer Cells via Suppressing NF-κB Activation

Background: Oligonol, a low molecular weight polyphenol derived from lychee fruit, not only has anti-inflammatory effects in various disease conditions but also has antitumor-promoting effects. We evaluate the nuclear factor-kappa B (NF-kappa B)-related anticancer effect of oligonol in ovarian cancer using SKOV-3 cells. Methods: Cell viability was examined after oligonol treatment using MTT assay and reactive oxygen species (ROS) production measurement. Subsequently, apoptotic cell death was visualized by the TdT-mediated dUTP nick-end labeling (TUNEL) method. The effect of oligonol on the NF-kappa B signaling pathway was evaluated using western blot analysis and luciferase activity measurement of p65, an NF-kappa B subunit. Results: Cell viability significantly decreased after oligonol treatment of 72 h. Apoptosis-related markers were highly expressed in oligonol-treated cells, and increased apoptosis after oligonol treatment was also confirmed using the TUNEL assay. Western blotting results showed the expression of NF-kappa B signaling pathway factors, p-ERK, TRAF2, and p-I kappa B alpha, increased following treatment with oligonol, whereas p65 and COX-2 expression decreased. Immunofluorescence imaging results showed p65 luciferase activity in the nucleus as well as a shift to cytoplasmic expression. Conclusion: Oligonol treatment significantly enhances apoptotic cell death in SKOV-3 cells, with the suppression of NF-kappa B activation, which plays an essential role in this anticancer effect.