The Effects And Mechanism Of GSK-3β On Chemoresistance Of Ovarian Cancer Cell Line SKOV3

Objective: There is a high death rate of ovarian cancer in China and other countries. One of the major reasons for the mortality of this cancer is chemotherapy resistance. But it is a pity that the mechanism of the drug resistance especially to the taxane or platinum-based chemotherapy which is the major chemotherapy drugs for ovarian cancer is not clear yet. Identifying the molecular mechanisms of tumor’s chemotherapy resistance and exploring resistance reversal agent of cancer cells are hot fields recently.Glycogen synthase kinase(GSK-3β)is a concerned molecule target in cancer therapy. Under this situation we aim to study the effects and mechanism of GSK-3β on chemoresistance of ovarian cancer cells.Methods: Li Cl was used to enhance the expression of p-GSK-3β(ser9)which is inactivated in ovarian cancer cell line—SKOV3. We use this method to establish a cell model in which there is a high inactivated GSK-3β level. MTT was used to choose the appropriate concentration and time of Li Cl and IC50 of cisplatin and paclitaxel. The expression of p-GSK-3β(ser9) was tested by FACS. The location of p-GSK-3β(ser9)in SKOV3 cells was analyzed by immunofluorescence. Results:According to the results of MTT, Li Cl 20 mmol/L treated for 6 hours is appropriate. After treated with Li Cl, the IC50 of cisplatin was increased from(20.37±0.56) μg/ml to(27.57±0.81)(t=12.66,P=0.0002)μg/ml for24 h,(7.79±0.72)μg/ml to(12.15±1.00)(t=6.13,P=0.0036) μg/ml for48 h,(2.8±0.32) μg/ml to(5.84±0.64)(t=7.36,P=0.0019) μg/ml for 72 h respectively with statistical difference. After treated with Li Cl, the IC50 of paclitaxel was increased from( 10.11±0.87) μg/ml to(12.54±0.88)(t=3.4,P=0.02) μg/ml for 24 h,(1.07±0.17)μg/ml to(2.22±0.3)(t=5.78,P=0.0045) μg/ml for 48 h,( 0.03±0.01) μg/ml to(0.093±0.03)(t=3.45,P=0.026)μg/ml for 72 h respectively with statistical difference. FACS results show that the mean fluorescence intensity of p-GSK-3β(ser9) increased from 661.67±37.63 to1191.33±30.37 after treated with Li Cl. The results of immunofluorescence show that the expression of p-GSK-3β(ser9) in nuclear increased obviously than in the cytoplasm. Conclusions: The augment of inactivated GSK-3β expression, especially in the nuclear,probably could improve the chemotherapy resistance of ovarian cancer cells. There is a high possibility that GSK-3β could be a molecule target to reverse the chemoresistance of ovarian cancer.