| Objectives To construct bifunctional graphene oxide drug loading system(Dox-GO-siStat3)and to investigate its effect on the proliferation of triple negative breast cancer cells.Methods Graphene oxide-doxorubicin-si-Stat3(Dox-GO-si-Stat3)complex was synthesized by chemical synthesis of nano-drug loading system.Dox and si-Stat3 were successfully loaded on GO by fluorescence spectrum and UV-vis spectrophotometer.The complex was dissolved in water,PBS solution,DMEM culture medium and serum.One week later,the dispersion and stability of the complex in different solutions were observed.Agarose gel electrophoresis was used to detect the binding ability of Dox-GO and si-Stat3 to determine the best concentration under different mass ratio conditions.The cell survival rate was detected by CCK8 method.The transfection efficiency of GO carrying si-Stat3 plasmid was evaluated by flow cytometry.In vitro,MDA-MB-231 cells were divided into four groups: GO group,Dox-GO group,GO-si-Stat3 group and Dox-GO-si-Stat3,PI staining method to detect the cell cycle after intervention.RT-PCR and Western blot were used to detect the expression of Stat3 gene and protein.To establish a subcutaneously transplanted tumor model of triple negative breast cancer in mice with MDA-MB-231 cells.The experiment was divided into four groups: NS group,Dox-GO-si-Stat3 group,Dox-GO group and GO-si-Stat3 group.The inhibition of tumor cells in each group was observed and the tumor inhibition rate was calculated.HE staining was used to observe the tumor cells in each group,immunohistochemical method was used to detect the expression of CD34 and PCNA,and automatic biochemical analyzer was used to detect the levels of BUN,ALT and AST in the blood of mice in each group to determine the effect on liver and kidney function.SPSS17.0 statistical software was used for analysis of variance.The data involved in the experiment were expressed by mean ±standard deviation.T-test was used to compare the differences between the two groups.Single factor analysis of variance was used for multigroup data.P<0.05,it was considered that the difference was statistically significant.Results The Dox-GO-si-Stat3 drug loading system was successfully synthesized,and the fluorescence intensity decreased when Dox and si-Stat3 were loaded on GO,and the absorption peak at 260 nm and 460 nm decreased by UV spectrophotometer,which proved the successful preparation of Dox-GO-si-Stat3 drug loading system,and observed that the system had good dispersion and stability in aqueous solution,PBS solution,serum and DMEM culture medium.Agarose electrophoresis showed that the binding ability of DoxGO to si-Stat3 was the strongest at 15:1 mass ratio.In vitro experiments showed that GO was a safe and effective gene delivery vector.RT-PCR and Western blot results confirmed that the expression of si-Stat3 decreased under the action of drug delivery system Dox-GOsi-Stat3,indicating that si-Stat3 was silenced and cell DNA replication decreased after silencing.In vivo experiments showed that Dox-GO-si-Stat3 significantly inhibited the growth of triple negative breast cancer xenografts in nude mice.The tumor weight and volume of Dox-GO-si-Stat3 group were significantly lower than those of other groups.HE staining showed that the cell structure disappeared and a large area of cell necrosis was found in the Dox-GO-si-Stat3 group.The results of immunohistochemistry showed that the number of proliferative tumor cells and microangiogenesis decreased in GO-si-Stat3 group.The concentrations of BUN,ALT and AST in the blood of mice in each group were in the normal range.Conclusions Functional graphene oxide is a safe and effective gene delivery vector,which can carry doxorubicin and Stat3-specific siRNA expression plasmids,which can significantly inhibit the proliferation of triple negative breast cancer cells.Figure 9;Table 5;Reference 82... |
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