CC1007Reverses Cisplatin-resistance On Ovarian Cancer By Targeting HDAC4Complex To Regulate STAT1Activation

Objective:To investigate the effect of new class Ⅱa histone deacetylase inhibitor CC1007on enhancing the chemotherapy and reversing cisplatin resistance on human ovarian cancer cell line HO8910、SKOV3and SKOV3/DDP, and the mechanism of CC1007reversing cisplatin-resistance on ovarian cancer by targeting HDAC4complex to regulate STAT1activation.Methods:1. Ovarian cancer cell SKOV3cultured in the media containing cisplatin to induce the drug-resistant cell line SKOV3/DDP in vitro by gradually increasing the concentration of cisplatin.2. Set up control group,cisplatin single used group,CC1007single used group and combination group, after treated for24hours,48hours,72hours, the cell proliferation inhibition rate of different concentration group on HO8910, SKOV3SKOV3/DDP were measured by MTT colorimetric assay;calculating the50%inhibition concentration(IC50) of cells and drawing the concentration-inhibition rate diagram and time-inhibition rate diagram, experiment repeat three times.3. Western blotting were used to detect HDAC4, STAT1and p-STAT1expression in HO8910,SKOV3,SKOV3/DDP cells at logarithmic growth phase before or after different concentration groups, experiment repeat three times.Results:1. After exposing SKOV3to cisplatin,drug-resistant cell line SKOV3/DDP was obtained,which can grow well in media with2.0ug/ml cisplatin, and the resistance index is3.33.2. Cell proliferation measured by MTT colorimetric assay:(1) CC1007single used group:the IC50of HO8910for48h was10.831±1.035μM, the IC50of SKOV3was60.462±1.781μM, the IC50of SKOV3/DDP was28.355±1.453μM.(2) Cisplatin single used group:the IC50of HO8910for 24h,48h and72h were5.492ug/ml,1.207ug/ml and0.762ug/ml; the IC50of SKOV3for24h,48h and72h were5.161ug/ml,3.081ug/ml and2.570ug/ml; the IC50of SKOV3/DDP for24h,48h and72h were32.817ug/ml,10.251ug/ml and6.470ug/ml;the inhibition rate was in time and dose dependent manner, the drug sensitivity of the three cell lines can be generalized as HO8910>SKOV3>SKOV3/DDP.(3) Combination group:the IC50of cisplatin combined with5uM CC1007for48h at HO8910was0.476ug/ml, the IC50of cisplatin combined with10uM CC1007for48h at SKOV3was1.81ug/ml,the IC50of cisplatin combined with lOuM CC1007for48h at SKOV3/DDP was3.572ug/ml; Low dose CC1007significantly enhanced the drug sensitivity of cisplatin on human ovarian cancer cell line HO8910,SKOV3and SKOV3/DDP.3. The result of Western blot showed that:(1) the expression of STAT1was positively related to the IC50of cisplatin;(2) the expression of HDAC4and ovarian cancer cisplatin-resistance was related, the expression of HDAC4in cisplatin-resistant cell line SKOV3/DDP was higher than that of SKOV3;(3) the expression of p-STAT1induced by cisplatin was increased in SKOV3/DDP with high expression of HDAC4, while the expression of p-STAT1induced by cisplatin was not detected in HO8910with much lower HDAC4expression;CC1007can inhibit the expression of p-STAT1induced by cisplatin.Conclusion:1. Low dose CC1007can significantly enhance the drug sensitivity of cisplatin on human ovarian cancer cell line HO8910and SKOV3, and reverse the cisplatin resistance of SKOV3/DDP at some level.2. There is a positive correlation between the expression of HDAC4and cisplatin-resistance of ovarian cancer cells,the cisplatin-resistance of ovarian cancer is related to high expression of HDAC4which can activate STAT1.3. CC1007can reserve cisplatin-resistance on ovarian cancer by targeting HDAC4complex to inhibit activation of STAT1.