Study The Mechanism Of Runt-related Transcription Factor2in Chemotherapy Resistance Of Hepatoma Carcinoma Cellmaster Degree Candidate

Background:Hepatocellular carcinoma is the fifth most common tumor in the world, and the mortality is the third place. In China,500,000new cases increase every year. Hepatocellular carcinoma has high malignant degree and poor prognosis. Doxorubicin is one kind of common chemotherapeutic drugs; however, its objective response rate is less than20%in hepatocellular carcinoma. One of the reasons for this phenomenon is chemotherapy resistance, and epithelial-mesenchymal transition might be the critical process. Runt-related transcription2(Runx2) is also called cbfal or AML3, which is the key transcription factor participating in osteoblasts proliferation and differation. Recently, many studies report that Runx2is related with many malignancies, including osteosarcoma, prostate cancer, breast cancer, pancreatic carcinoma, ovarian cancer, colon cancer and thyroid cancer. There is no study about Runx2in chemotherapy resistance of hepatocellular carcinoma; however, some studies have demonstrated that high Runx2levels might cause epithelial-mesenchymal transition in cancer cells, and some other studies have already prove the relationship between chemotherapy resistance and EMT in hepatocellular carcinoma.Aim:To study the expression of Runx2in hepatocellular carcinoma, and the relationship with chemotherapy resistance, and to find out the meschanism between Runx2and EMT.Methods:Select62hepatoma patients receving treatment in The First Affiliated Hospital of Zhengzhou University from2012Jan to2013Jan as objects of study and use immunohistochemistry to test Runx2expression in samples. In vitro, Hep3B, HepG2, Huh-7and SNU-449cells as research objects and cell proliferation assay, Western blotting, wound-healing assay combining with siRNA interefence were used to test the change of doxorubicin chemosensitivity and epithelial or mesenchymal phenotype.Results:In62hepatoma patients’ tissue samples,75.81%had Runx2expression. In those patients who had metastasis,33.87%and24.19%belonged to positive and strong positive. In those patients who had chemotherapy resistance,52.38%and38.10%belonged to positive and strong positive. As those patients who were sensitive to chemotherapy, only9.38%were strong positive, and positive or weak positive were25.00%or43.75%respectively, and21.87%were negative. In vitro, SNU-449cells had highest Runx2expression and resistance to doxorubicin, and Runx2had lowest Runx2expression and the most sensitive to doxorubicin. When Runx2expression was inhibited, the sensitivity to doxorubicin in all four hepatoma cell lines was increased. Furthermore, SNU-449cells, which had high Runx2expression belonged to mesenchymal phenotype and Hep3B belonged to epithelial phenotype. As to HepG2and Huh-7, they both had epithelial and mesenchymal characters. In addition, we have found epithelial hepatoma cells were more sensitive to doxorubicin than mesenchymal cells. After mesenchymal character was weaken, the hepatomal cell sensitivity to doxorubicin was increased. Runx2could participate in regulating epithelial-mesenchymal transition and inhbiting Runx2could decrease mesenchymal character and enhance epithelial character and increase the curative effect of doxorubicin chemotherapy.Conclusion:In this study, we proved high level Runx2could cause epithelial-mesenchymal transition in hepatocellular carcinoma cells and lead to doxorubicin resistance or high migration ability. Runx2inhition could reverse epithelial-mesenchymal transition and enhance chemosensitivity, and decrease the migration ability of hepatocellular carcinoma cells.