Study On The Mechanism That Germacrone Inhibits Proliferation Of Bel7402Cells

Rhizoma curcuma, a valuable Chinese traditional medicine, has been massivelyapplied into clinical therapy in Chinese medicine because of its anti-inflammatory,hepatoprotective, anti-bacterial, anti-thrombotic and anti-tumor properties. Germacrone isa kind of sesquiterpene extracted from R. curcuma, and has been reported to possessplenty of pharmacological properties while the anti-cancer mechanism has not thoroughlyunderstood yet. The present study is to clarify the effect of germacrone on Bel7402through MTT, Flow Cytometry, Western Blotting and so on. And the main research resultsare as follows.（1）Germacrone selectively inhibited the proliferation of Bel7402cells in dose-dependentmanner while exhibited no obvious time-dependent tendency. The MTT assay resultsshowed higher germacrone concentration caused higher growth inhibitory rate of Bel7402cells. And there was no statistically significant difference between treatments for24h and48h. IC50for24h treatment with germacrone was160μM. Furthermore, the sametreatments on normal human liver cell LO2cells revealed little side-effects.（2）Germacrone dose-dependently induced the apoptosis of Bel7402cells and raised itsoxidative damage. By means of the Hochest staining and Flow cytometry assay, we foundthat higher concentration of drug led to the more obvious inhibitory effect. In addition, theWestern Blotting results demonstrated that germacrone induced the expression ofanti-cancer gene P53and Bax while repressed the expression of anti-apoptosis gene Bcl-2.Furthermore, germacrone efficiently up-regulated the ROS level in Bel7402cells. All theresults exhibited that germacrone had the potential to promote the apoptosis and involvedin the oxidative damage in Bel7402cells.（3）Germacrone induced the apoptosis of Bel7402cells through the JAK2/STAT3signalpathway. We set several different treatments on Bel7402cells by using germacrone andIL-6, the agonist of JAK2/STAT3signal pathway, and the Western Blotting resultsindicated that germacrone down-regulated the expression level of p-STAT3and IL-6hadthe opposite effect, in the meanwhile, the expression level of P53showed opposite trend.In conclusion, all the results demonstrated that germacrone suppressed thephosphorylation of constitutional activation factor STAT3, thus up-regulated thedownstream protein expression level of P53.In short, our research successfully proved that germacrone had very obviousinhibitory effect on Bel7402cells and little side-effect on normal human liver cells, whichmight be used as a new anti-cancer drug in liver cancer therapy.