The Effect And Mechanism Of Curcumin Mediated By The Dual-specificity Phosphatase-2 (DUSP-2) In Human Glioblastoma

Objective glioblastoma is the most common primary intracranial tumor in human,which is divided into low-grade glioma and high-grade glioma according to the WHO classification,and the glioblastoma belongs to the high-grade glioma with high malignance,strong ability of proliferation and invasion.At present,the clinical treatment of glioma is given priority to with comprehensive treatment of surgery combined radiotherapy or chemotherapy,but the glioblastoma is prone to tolerance of radiation and chemotherapy,and the recurrence rate is still high.Therefore,it is particularly important of looking for a safe and effective drug targeting glioblastoma.In recent years,the antitumor effect of traditional Chinese medicine monomer has been gradually widely recognised,however its further anti-cancer mechanism has not been fully revealed.The traditional Chinese medicine monomer curcumin has been shown significant curative effect on a wide variety of tumors,but its mechanism remains further research.This research studied the effect of curcumin on human glioblastoma cell line U87's proliferation,apoptosis and invasion,and detected the expression of double specificity phosphatase-2(DUSP-2),which confirmed that DUSP-2 is the key molecule in mediating the anticancer effect of curcumin on human glioblastoma.Methods 1)Different concentration of curcumin(0,10,20,30,40,60 uM)were added into the complete DMEM for human glioblastoma U87 cells.CCK8 detection kits were used to test the cells' vitality and draw the curve of cell vitality.The Annexin V-FITC/PI apoptosis detection kit was used to test the apoptosis.Transwell crystal violet staining detected the U87 cells' invasive ability.2)Western blot tested the expression of double specific phosphatase-2,MAPK signal pathways(p-ERK,ERK,p-JNK,JNK)of blank control group and curcumin group.3)U87 cells were injected to subcutaneous of the right back and right caudate nucleus of intracranial brain in nude mice,then,given the curcumin lavage for 50 mg/(Kg · d)to observe the subcutaneous and intracranial tumor growth and survival period of nude mice.4)U87 cells were knocked down DUSP-2 by shRNA,repeat the above steps to verify that DUSP-2 is the key molecular which mediates the anticancer effect of curcumin on glioblastoma.Results 1)CCK8 experiments suggested that curcumin shows obvious concentration-dependent inhibitory effect on glioblastoma cells.AV/PI experiments found that the apoptosis rate of blank control group was 2.002 ± 0.22%,10 uM group was 3.850 ± 0.39%,20 uM was 7.990±0.70%,30 uM was 10.23±0.45%,40 uM was 14.61 ± 0.32%,which confirmed that curcumin can promote U87 cells' apoptosis;Transwell invasion experiment also showed that curcumin can markedly inhibit the invasive ability of U87 cells.2)Western blot experiments found that curcumin can promote the expression of DUSP-2 and inhibit the phosphorylation of MAPK pathway.3)The research on nude mice in vivo models also confirmed the inhibitory effect of curcumin on glioblastoma,and that curcumin can significantly prolong the lifetime of tumor-burdened nude mice.4)The inhibitory effect of curcumin on glioblastoma was markedly reduced and the phosphorylation of MAPK downstream also remained at a higher level in the absence of DUSP-2.Conclusion curcumin has an excellent therapeutic effects on glioblastoma,which can inhibit the proliferation and invasion of glioblastoma,and promote its apoptosis.Double specificity phosphatase-2(DUSP-2)mediates the targeted therapeutic effect of curcumin on glioblastoma.