Study On The Proteasomes Inhibitor To Induce Ovarian Cancer Lines Apoptosis

Ovarian cancer is the one of three malignant tumor in the department of gynecology. As the development of population aging, there is a trend of increasing ovarian cancer incidence rate.The traditional therapeutic tool of ovarian cancer lack tumor tissue specificity, so targeted therapy become a new tendency of the ovarian cancer therapy. Chemoresistance remains a major therapeutic problem. Researching new chemotherapeutics and overcoming drug resistance is a key to successful treatment of ovarian cancer.At present, molecule targeted therapy has been the main research direction that scientists explore the molecular biology pathogenesy and therapy of tumors in the world. The neotype molecule targeted drug has got outstanding curative effect in clinical practice, time indicated that the theory of molecule targeted therapy has correctness and profession. The theory of molecule targeted therapy take the therapy of tumors to push a unprecedented new stage.Inhibition of the proteasome activates multiple mechanisms capable of arresting tumour proliferation, tumour spread, and angiogenesis. The chemical name of PS-341 is Bortemzomib.Bortezomib was the first proteasome inhibitor to enter clinical trials,and it is the most fittest proteasome inhibitor to carry out clinical trial at present. Bortezomib is a novel boronic acid dipeptide that potently and selectively inhibits the 26S proteasome. It inhibits the activity of 20S proteasome catalytic center.Accordingly, it selectivitly inhibits the proteinaceous degradation to process important regulation effective.Bortezomib caused G2/M cell cycle arrest and apoptosis. Preclinical studies show that compared with normal cells, cancer cells appear to be more sensitive to the pro-apoptotic effects of proteasome inhibition. Bortezomib has been the one of the most prosessed application perspective medicine to aim directly at molecule targeted therapy. In experimental models of breast, lung, colon, prostate, pancreatic, and ovarian cancer, bortezomib shows additive or synergistic activity when combined with chemotherapeutic agents such as irinotecan, gemcitabine, 5-fluorouracil, cisplatin, paclitaxel, docetaxel, and doxorubicin. So this experiment aim directly at the PS-341 of proteasomes inhibitor that induce ovarian cancer cell line apoptosis to carry out correlated research .The human ovarian cancer cell lines, SKOV-3 and SKOV-3/DDP, were cultured in vitro and PS-341 was divided into 0.05 to 5.0 ummol/L at concentration. 24,48 and 72 hours later, MTT assay were used to detect cytoactive and inhibition ratio. Then we found as follws:(1)Accompanied the increase of PS-341 concentration, the different concentration of PS-341 did not inhibit the proliferation of two cell lines in 24 hours; (2)After 48 hours, accompanied the increase of PS-341 concentration, the 0.05 to 5.0 ummol/L concentration of PS-341 all inhibited the proliferation of two cell lines. In detection range concentration, accompanied the increase of PS-341 concentration and action time, the inhibitions of two cell lines were significantly increased and showed a time-and-dose-dependent manner. (3) PS-341 (the concentrations respectively were 0.25 and 0.5 umol/L) combined with cisplatin (the concentration was 2.5μg/ml) to deal with SKOV-3/DDP cell line, we used MTT assay to detect cytoactive and inhibition ratio after 24,48 and 72 hours.We found that the diffferences of the proliferativein inhibition rates among the cisplatin, PS-341, PS-341 combined with cisplatin groups were also statistically significant accompanied the increase of PS-341 concentration and action time.It indicated that PS-341 combined with cisplatin can enhance the lethal effect to SKOV-3/DDP cell line.In addition,we also used flow cytometry to detect apoptosis ratio through Annextin V/PI assay.It shows that PS-341 can induce the human ovarian cancer cell line (SKOV-3 and SKOV-3/DDP) to apoptosis and PS-341 combined with cisplatin obviously can induce SKOV-3/DDP cell to apoptosis. Then we can confirm that the PS-341 of proteasomes inhibitor can active suppression the growth of the human ovarian cancer cell line ,induce them apoptosis and overcome drug fast of SKOV-3/DDP cell to cisplatin.At using flow cytometry to detect cell cycle,we found that as follows: (1) After the PS-341 of proteasomes inhibitor deal with SKOV-3/DDP cell, cell cycle changed that the percentage of the G0/G1 stage degrade and the percentage of the G2/M stage advanced.Thereby,we presume that PS-341 induce SKOV-3/DDP cell apoptosis because cell cycle block in the G2/M stage. (2) Cell cycle block in the S stage when cisplatin alone effect SKOV-3/DDP cell; cell cycle block in the G2/M stage when PS-341 alone effect SKOV-3/DDP cell;but cell cycle evidently block in the S stage when PS-341 combined with cisplatin effect SKOV-3/DDP cell.The concrete mechanism need deeply research.We also used immunohistochemistry assay to detect the change of bcl-2 and bad protein in ovarian cancer cell lines which were dealed with PS-341.We found that the expression level of bcl-2, antiapoptotic proteins,was degraded and the express level of bad, proapoptotic proteins ,was increased. This experimental result maybe correlate with the change of AKT protein which regulate the change of bcl-2 and bad protein in PI3K-AKT pathway.Above results all provide the theory basis for the PS-341 of proteasomes inhibitor applied for utilizing the clinical therapy of ovarian cancer .At same time,they all provide the idea of treatment and the experiment support for the chemotherapy of ovarian cancer and the therapy of recrudescent and refractory ovarian cancer.