Effects Of Curcumin, Demethoxycurcumin And Bisdemethoxycurcumin On Expression Of UPA System Proteins In Human Hepatoma Cell Line HepG2

Objective: Hepatocellular carcinoma (HCC) is the fifth commonmalignant tumor in the world, the third cause of turmeric death, and thesecond in our country. China has the highest incidence of liver cancer in theworld, which is as much as98.9/100,000. With the increasing incidence, it isbecoming one of the diseases seriously threatening people’s health.Liver cancer is commonly considered as king of cancers, for625millionnew cases occur every year, which makes up4%of all cancers. Liver cancercauses600million deaths every year which roughly equals the number of newcases, and40%of the deaths occur in China. Liver cancer can easily migrateto other location because of its high malignancy and hided onset. It is oftendiscovered at advanced stage. Because of which, liver cancer has a veryterrible prognosis with less than half a year natural lifetime.Matastasis of turmer cells is the result of the degration of extracellularmatrix (EMC), including laminin, fibronectin proteoglycan and collagen IV.uPA, a kind of serine protease which effects by combining to its receptor,uPAR， belongs to proteolytic enzymes. It not only actives plasminogen, butalso collagenase. Besides, uPA mediates the degradation of fibrin which leadsto the dissolve of EMC and basilar membrane, and finally the migration oftumor.PAI-1, the inhibitor of uPA, can regulate the activity of the latter. However,it is still unfamiliar how it effects in oncobiology. PAI-1is reported to be akind of protector that prevents the tumor from own degradation. It is alsoreported that PAI-1, uPA and uPAR regulate each other in the process ofmigration of tumor.Some studies show that curcumin has the effects of anticancer function. It not only inhibits the growth of tumor but also the migration. Increasingattention is being paid to the function of the inhibition of migration. Curcumin,demethoxycurcumin and bisdemethoxycurcumin are abstracted from therhizomes of Curcuma-Turmeric. They perform similar anticancer functions.Some researchers ever treated breast cancer cells with curcuminoids, theexpression of uPA and uPAR is down regulated, while the expression of PAI-1,the inhibitor of uPA, is up regulated, all the effects are dose dependent. Theeffects of curcuminoids on the expression of uPA， uPAR and PAI-1in livercancer cells are rarely researched. This study is to demonstrate how thecurcuminoids effect the three proteins in order to discuss whether they effectthe migration of liver cancer cells.Method: Cultivate Hepatocellular carcinoma cell line HepG2in general.Inhibition of different curcumin concentrations (10μmol/L,20μmol/L,40μmol/L,80μmol/L) for24h,48h and72hours to HepG2cells proliferation wasdetected by MTT. Expression of uPA，uPAR，PAI-1in HepG2cells under theeffect of different curcumin concentrations (20μmol/L,40μmol/L) anddifferences among the expression of them treated by curcumin,demethoxycurcumin and bisdemethoxycurcumin (60μmol/L) was detected byWestern-Blot.Result: curcumin, demethoxycurcumin, bisdemethoxycurcumin caninhibit the growth of HepG2cells, with a time and dose-dependentmanner(P<0.05). The inhibitory rate of demethoxycurcumin andbisdemethoxycurcumin are both higher than that of curcumin at40μmol/L at48hours(P<0.05), and the inhibitory rate of bisdemethoxycurcumin is higherthan that of curcumin at80μmol/L at72hours(P<0.05).It is shown that the expression of uPA and uPAR is down regulated whilethe expression of PAI-1is up regulated after treated with curcumin,demethoxycurcumin and bisdemethoxycurcumin in the HepG2cells, with adose-dependent manner. The strongest inhibitor of the uPA and uPAR isbisdemethoxycurcumin, and the weakest is curcumin, and the strongestactivator of PAI-1is demethoxycurcumin while the weakest is curcumin(P<0.05).Conclusion: curcumin, demethoxycurcumin and bisdemethoxycurcumincan inhibit the growth of HepG2cells, with a time and dose-dependentmanner(P<0.05). The curcumin has the weakest inhibitory rate of the three.All of the three can down regulate the expression of uPA，uPAR and upregulate the expression of PAI-1, with a dose-dependent manner, comparedwith curcumin, demethoxycurcumin and bisdemethoxycurcumin have strongereffect.