EGCG combined with radiation in the treatment of xenotransplanted nasopharyngeal carcinoma in nude mice

OBJECTIVE To study the expression and significance of survivin and VEGF mRNA in xenotransplanted nasopharyngeal carcinoma after treated by EGCG combined with radiation in nude mice.METHODS Nasopharyngeal carcinoma CNE-2 cells were cultured in vitro and injected subcutaneously into twenty male nude mice to establish human tumor xenografts.When the diameter of the tumors reached 4 to 6 mm,the twenty nude mice were randomly divided into four groups: control group,EGCG group,radiation group,EGCG combined with radiation group.Three weeks later,the mice were killed and the tumor weight was measured to calculate the tumor inhibition rate.HE staining was used to observe the pathological changes of the tumor.Apoptosis rate was detected with flow cytometry.One step RT-PCR was applied to detect the expression of survivin and VEGF.RESULTS EGCG combined with radiation group could apparently inhibit the tumor growth compared with control group.Apoptosis rate were significantly increased in the other three groups except the control group,especially in EGCG combined with radiation group.Furthermore,the expression level of Survivin and VEGF in EGCG combined with radiation group were the lowest among the four groups(P 0.01).CONCLUSIONEGCG can improve the CNE-2 xenografts sensitivity to radiotherapy.The inhibition of the expression of Survivin and VEGF mRNA may be the possible mechanism.