Effect of Pterostilbene Regulating Nuclear Factor E2-Related Factor 2 on Apoptosis of Colon Cancer Cells in Vitro
Objective To investigate the effects of pterostilbene on human colon cancer LoVo cells and study the regulatory mechanism of nuclear factor E2-related factor 2(Nrf2)in the process of pterostilbene acting on LoVo cells.Methods LoVo cells were treated with different concentrations(5,10,20,40,60,80,100 panol/L)of pterostilbene.Cell viability,migration,invasion,and apoptosis were examined by CCK-8,scratch,Tran-swell,and TUNEL assays,respectively.The mitochondrial membrane potential was measured by the mitochon-drial membrane potential assay kit with JC-1.The reactive oxygen species level was measured by 2',7'-dichlo-rofluorescein diacetate.The protein levels of Nrf2,phosphorylated Nrf2,heme oxygenase 1,and apoptotic pro-teins(Bcl2 and Bax)were determined by Western blotting.In addition,cell viability,Nrf2 expression,and ap-optosis rate were determined after co-application of the Nrf2-specific agonist sulforaphane.Results Compared with the control group,40,60,80,100 µmol/L pterostilbene reduced the viability of LoVo cells(P=0.014,P<0.001,P<0.001,P<0.001).Pterostilbene at 5,10,20 µmol/L did not show effects on cell viability but inhibited cell migration(P=0.008,P<0.001,P<0.001)and invasion(all P<0.001).Pterostilbene at 40,60,80 μmol/L increased apoptosis(P=0.014,P<0.001,P<0.001),promoted mitochondrial membrane potential depolarization(P=0.026,P<0.001,P<0.001)and reactive oxygen species accumula-tion(all P<0.001),and down-regulated the expression of phosphorylated Nrf2(P=0.030,P<0.001,P<0.001),heme oxygenase 1(P=0.015,P<0.001,P<0.001),and Bc12(P=0.039,P<0.001,P<0.001)in LoVo cells.Pterostilbene at 60,80 µmol/L down-regulated Nrf2 expression(P=0.001,P<0.001)and up-regulated Bax expression(both P<0.001).The application of sulforaphane reversed the effects of pterostilbene on cell viability(P<0.001),apoptosis(P<0.001),and Nrf2 expression(P=0.022).Conclusion Pterostilbene is a compound that can effectively inhibit colon cancer cells by inhibiting the Nrf2 pathway.
pterostilbenenuclear factor E2-related factor 2colon cancerapoptosisreactive oxygen species