Resveratrol Prohibits Cell Proliferation And Induces Apoptosis In Hepatocellular Carcinoma Cell Lines

Resveratrol (Res), a phytoalexin found at high levels in grapes and in grape products suchas red wine. Besides anti-inflammatory and anti-aging properties, resveratrol also has been foundinhibitory effect on the development process of various kinds of cancers in recent studies. SIRT1is an important downstream target molecule of resveratrol. Knockdown of SIRT1abolished theinhibitory effect of resveratrol on gastric cancer cells. Nathan et al. found that SIRT1wasessential for the inhibitory effect of resveratrol on cancer cells through SIRT1-deficient andSIRT1-overexpression mice xenograft tumor model. In Hodgkin lymphoma, resveratrol inducedcell apoptosis by down-regulating the expression of SIRT1. Pacholec et al. found thatresveratrol was not a direct activator of SIRT1in vitro. Therefore, the roles of SIRT1inresveratrol prevention and treatment of cancer require further exploration. As a deacetylase,SIRT1can regulate a variety of protein activities, such like p53, FoxOs, NF-κB which play keyroles in cell growth and differentiation. Tumor suppressor gene p53can monitor the integrity ofgenes. When cell is severely damaged, it can trigger mitochondria dependent apoptosis pathway.In gastric cancer, breast cancer and other cancer cells, resveratrol induces cell apoptosis byup-regulating the expression of p53. Forkhead boxO (FoxOs) is a tumor suppressor gene,resveratrol can modulate the activity of FoxOs in a variety of ways. In pancreatic cancer,resveratrol induced cell apoptosis through inhibiting PI3K/AKT and MEK/ERK pathways andactivating downstream genes expression. Although there are lots of studies about resveratrolinducing cell apoptosis through SIRT1、FoxOs、p53pathways, but the roles of SIRT1、FoxOs、p53in resveratrol prevention and treatment of hepatocellular carcinoma cells is still not clear.Our results showed that: resveratrol significantly inhibited the cell proliferation of livercancer in a dose-dependent manner, and more significant inhibitory effect on liver cancer celllines HepG2、SSMC-7721、Bel-7402than that on normal liver cell line HL-7702. Half inhibitoryconcentrations of resveratrol to liver cancer and normal liver cells lines were IC50(HepG2)=109μΜ, IC50(SSMC-7721)=105μΜ, IC50(Bel-7402)=128μΜ, IC50(HL-7702)=162μΜ.Hoechst/PI staining was used to investigate the mechanism of resveratrol prohibited cell activity. The result showed that resveratrol significantly increased the percentage of apoptotsiscells in a dose-dependent manner. In order to further explore the molecular mechanism ofapoptosis induced by resveratrol, western blot was used to detect the expression of p53and Bim.Resveratrol induced cell apoptosis by activating p53and Bim expression. SIRT1, FoxO1andFoxO3are important target molecules of resveratrol which can regulate the activites of p53andBim. Therefore, we used RT-PCR and western blot to detect whether resveratrol induced cellapoptosis through SIRT1or FoxOs pathway. The result showed that100μΜ resveratrol had noeffect on SIRT1expression. And confocal images showed that resveratrol didn’t lead to SIRT1nuclear translocation. While resveatrol significantly up-regulate the expression of FoxO1、FoxO3and acetylated FoxO1(ac-FoxO1). These results demonstrated that resveratrol induced cellapoptosis depending on two pathways. One is to activate p53pathway and the other is toup-regulate the expressions of FoxO1、FoxO3and ac-FoxO1which further activate Bim toinduce mitochondrial-dependent cell apoptosis.