Reverse Effect Of The 4'-Methery-scutellarein On Multidrug Resistance Of Human Choriocarcinoma In Vivo

To find out a new multidrug resistant(MDR)reverse medicine or method.Based on our previous studies,we established a MDR model of human choriocarcinoma in nude mice.The reverse effect of 4'-Methery-scutellarein(4'-M-S)on MDR of human choriocarcinoma and its related mechanism were explored in vivo.This project consists of the following 2 parts.1.Establishment of multidrug resistant model of human choriocarcinoma in nude miceThe MDR model of human choriocarcinoma was established by injecting JAR/VP16 cells subcutaneously into nude mice.Tumors began to form on 8～10 days after implantation,the tumorigenesis rate was 100%(20/20).The morphological and ultrastructural characteristics of the formed tumors were quite similar to the parental JAR/VP 16 cells.The tumor cells in nude mice expressed high level of mdrl mRNA by semi-quantitative reverse transcriptase polymerase chain reaction (RT-PCR).Meanwhile,The results of flow cytometry(FCM)analysis suggested that the intracellular retention of rhodamine123(Rh123)in the xenografts obviously reduced compared with JAR cells.In conclusion, the xenografts model in nude mice is similar to multidrug resistant human choriocarcinoma in histological and biological characteristics.It could reflect the growing process of human choriocarcinoma.Thus,this study could provide an ideal animal model for the further study of MDR in human choriocarcinoma.2.Reverse effect of 4'-Methylether-scutellarein on multidrug resistance of human choriocarcinoma model in nude miceTo observe the reverse effect of 4'-M-S on multidrug resistance of human choriocarcinoma in vivo,we raised human choriocarcinoma model in BALB/c nude mice.Then the animals were randomized into 4 groups:control group,etoposide(VP16)group,4'-M-S group and 4'-M-S+VP16 combined group.After treated with the combination of 4'-M-S and VP16,the tumor volumes of nude mice were significantly suppressed,the toxicity of chemotherapy was eased,and the mean survival time was obviously prolonged.The earlier apoptotic changes were observed under light and transmission electron microscope(TEM). The apoptotic rate was significantly increased by FCM assay. Furthermore,the express levels of mdr1 mRNA,1rp mRNA and their products P-gp,LRP were decreased measured by RT-PCR and Western blot.In summary,our study established a multidrug resistant subcutaneous xenografts model of human choriocarcinoma using nude mice,providing a further experimental foundation for exploring the mechanism and reverse methods of drug resistant choriocarcinoma.In addition,our findings indicated that 4'-M-S could efficiently reverse the resistance of tumor xenografts to chemotherapeutics,induce cell apoptosis and down-regulate the express levels of mdr1 mRNA,1rp mRNA and P-gp,LRP.