Antitumor Effect And Mechanism Of Resveratrol And Its Derivatives On Ovarian Cancer

Ovarian cancer is the most common malignant tumor of the reproductive system.Due to the lack of specific manifestations in the early stage,most ovarian cancer patients are diagnosed at an advanced stage,so the mortality rate is the highest and the prognosis is the worst,therefore,the prevention and treatment of ovarian cancer is crucial.Epidemiological studies have shown that obesity and hyperlipidemia are closely related to the development of ovarian cancer,and they are not only risk factors for ovarian cancer,but also associated with poor prognosis,which indicates that disorders of lipid metabolism are risk factors for ovarian cancer.Resveratrol（Res）is a natural plant polyphenol with antitumor and antioxidant effects.Res has been reported to improve lipid metabolism levels in mice with non-alcoholic fatty liver disease,thereby reducing liver pathological damage.Recent studies suggest that disorders of lipid metabolism are closely related to the development of ovarian cancer,and Res has a potential role in regulating lipid metabolism.However,the unstable structure,rapid metabolism and low bioavailability of Res largely hinder its role and limit its application in clinical practice,so most studies have focused on methoxylated resveratrol derivatives:pterostilbene,pinostilbene,3,4′,5-trimethoxy-transtilbene and 4′-methoxyresveratrol.On the basis of the previous work,we proposed the hypothesis:whether the antitumor effect of Res and its derivatives could inhibit the growth of ovarian cancer by regulating the lipid metabolism pathway.In this study,we applied ovarian cancer A2780 cell line for in vitro study to investigate whether Res and its derivatives（pterostilbene,pinostilbene,3,4′,5-trimethoxy-transtilbene and4′-methoxyresveratrol）could exert antitumor effects on ovarian cancer through regulating lipid metabolism disorder,and to preliminarily explore their possible mechanisms.The effect of Res and its derivatives on cell proliferation viability was detected by CCK-8 and clone formation assay,Annexin V-FITC/PI double-staining flow cytometry and Hoechst33258fluorescence staining to detect the effect of Res and its derivatives on apoptotic rate and morphological changes of ovarian cancer cells,as well as on cell cycle distribution;Transwell and scratch assay to assess the effects of resveratrol and its derivatives on the migration ability of ovarian cancer cells;western blotting to detect the protein ofβ-catenin,SREBP1 and its downstream SCD1 expression levels.The results of cell migration assay showed that the migration ability of ovarian cancer A2780 cell line was attenuated by treatment with Res40μmol·L^-1,pterostilbene,pinostilbene,3,4′,5-trimethoxy-transtilbene and4′-methoxyresveratrol at low dose concentrations of 20μmol·L^-1 for 24h.The difference was statistically significant（P<0.01）,and when the treatment time was extended to 48h,Res and its derivatives could significantly inhibit the migration ability of A2780,and the difference was statistically significant compared with the control group（P<0.01）;when the same concentration of drug group treated cells for 24h,Transwell migration assay found that the number of cells crossing the bottom of the cell chamber in the experimental group was about 1/2 of that in the control group,and the difference was statistically significant（P<0.01）.The results of cell proliferation assay showed that the CCK-8 assay observed that Res and its derivatives significantly inhibited the proliferation of A2780 when the cells were intervened with the concentrations of Res125μmol·L^-1,pterostilbene,pinostilbene,3,4′,5-trimethoxy-transtilbene and4′-methoxyresveratrol 40μmol·L^-1for 24h,and the IC50 values of the derivatives were lower than those of Res.The same concentration of drug treated cells for 24h,the clone formation assay showed that the number of colony formation in the experimental group was approximately 1/3 of that in the control group,and the difference was statistically significant（P<0.01）.The results of flow cytometry experiments showed that after 24h of cell intervention with Res 125μmol·L^-1,pterostilbene,pinostilbene,3,4′,5-trimethoxy-transtilbene and 4′-methoxyresveratrol 40μmol·L^-1,revealed that the apoptosis rate of 4′-methoxyresveratrol and pinostilbene group was higher than that of the control group,and the difference was statistically significant（P<0.05）.The apoptosis rates of 3,4′,5-trimethoxy-transtilbene,pterostilbene and Res were significantly higher than those of the control group,and the differences were statistically significant（P<0.01）.Hoechst33258 fluorescence staining experiment observed that the cells in the experimental group showed obvious apoptotic morphology,with solidified and fragmented nuclei and bright blue fluorescence.Flow cytometry detected that Res and its derivatives blocked the cell cycle in the G0-G1 phase,and the difference was statistically significant（P<0.01）.Western blotting results suggested that Res and its derivatives may inhibit fatty acid metabolism and thus exert anti-tumor effects by inhibiting the Wnt/β-catenin pathway and down-regulating the protein expression levels of SREBP1 and its downstream SCD1.In conclusion,Res and its derivatives（pterostilbene,pinostilbene,3,4′,5-trimethoxy-transtilbene and 4′-methoxyresveratrol）have significant antitumor effects,which are manifested by inhibiting cell proliferation,promoting apoptosis,attenuating migration,and blocking cell cycle.And its anti-tumor mechanism may be through the inhibition of Wnt/β-catenin pathway,down-regulation of protein expression levels of SREBP1 and its downstream SCD1,which inhibited fatty acid metabolism and thus exerted anti-tumor effects.This suggests that Res and its derivatives have the potential to treat ovarian cancer.