Synergistic Effect Of TSA And PS-341in The Treatment Of Taxol-resistant Ovarian Cancer Cells

Background and Objective Ovarian cancer is one of the three female genital malignant,although the treatment of ovarian cancer is improving, but its caused mortality rate stillaccounts for the first one in the female genital malignancy. The treatment in advancedovarian cancer is tumor cytoreductive surgery combined with chemotherapy, and thecurrent clinical standard chemotherapy is still the combined administration of platinum-and taxane-based chemotherapy(TP). At least70%of advanced ovarian cancers willrespond to the chemotherapy, but studies have shown that the initial efficacy of thiscombination chemotherapy is noe durable and the tumor cells are available to drugresistance. The purpose of this study is to explore the synergistic efficacy of theproteasome inhibitor PS-341certified by FDA and histone deacetylase inhibitor TSA in thetreatment of taxol-resistant ovarian cancer cells.Method The taxol-sensttive human ovarian cancer cell line (A2780) and its resistantvariant (A2780T) were cultured in RPMI1640supplemented with10%FBS and thentreated with Taxol, TSA+PS-341at different times and in different concentrations.①UseMTT assay method to confirm the proper concentrations.②Use flow cytometry to detectthe cell apoptosis and cell cycle respectively. gentian violet staining to assessed the cellproliferation.③Use Western Blot to test the proteins related with the cell cycle.④Thecells of A2780T were transfected by cyclinB1siRNA and control siRNA. And treated byTaxol and TSA+PS-341respectively.⑤Use flow cytometry to detect the cell apoptosis andcell cycle after the silence of cyclinB1. gentian violet staining to assessed the cellproliferation. Results①MTT assay determine the proper concentration of Taxol is1umol/L andTSA+PS-341is500nmol/L+40nmol/L.②A2780cells and A2780T cells treated withTSA+PS-341have significant G2/M period of cell cycle arrest and apoptosis, theinflurence of cycle arrest and apoptosis in A2780T cell after treated by Taxol is not obvious.③Western blot detection of cell cycle proteins found higher levels of expression ofcyclinB1in A2780T.④A2780T cells were treated with Taxol and TSA+PS-341after thesilence of cyclinB1induce the blockade of G2/M phase and apoptosis.Conclusion①The usage of the combination with TSA and PS-341in the taxol-resistantovarian cells can induce arrest in cell cycle G2/M phase and significantly increase theapoptosis rate.②the inhibition of cyclinB1expression can increases taxol-resistant ovariancancer cell sensitivity to chemotherapy of taxol.