| Objective To investigate the effect and mechanism of brucine on the growth of subcutaneous xenograft tumor in nude mice with MDA-MB-231 cells in tri-negative breast cancerMethods MDA-MB-231 in logarithmic growth phase was injected subcutaneously into nude mice to construct a subcutaneous xenograft model of triple negative breast cancer in nude mice,and the nude mice that were successfully modeled were randomly divided into low,medium and high dose groups of brucine(15,30,60mg/kg),positive control group(paclitaxel 5 mg/kg)and negative control group(1%DMSO).The brucine group and the negative control group were administered by intragastric administration once a day,and the paclitaxel group was intraperitoneally injected once every two days for 4 weeks.The body weight of the nude mice,the length and the short diameter of the transplanted tumor were measured twice a week,the volume of the transplanted tumor was calculated according to the formula.The nude mice were sacrificed by cervical dislocation method the next day after the end of treatment,and the transplanted tumor was removed.To observe the effect of brucine on the growth of subcutaneous xenografts in nude mice,and calculate the size,weight and tumor growth inhibition rate of xenografts in nude mice,and evaluate the proliferation of tumor cells by cell proliferation-associated nuclear antigen(Ki-67)staining;apoptosis in situ end labeling(TUNEL The experiment)and apoptosis protein Caspase-3 immunohistochemical staining were used to evaluate the effect of brucine on apoptosis of transplanted tumor cells in nude mice.Three-negative breast cancer MDA-MB-231 cells were cultured in vitro,and were treated with different concentrations of brucine(25,50,100,200,400?g/m L).The total protein in the cells was collected after 48 h,and the expression level of cysteine aspartic protease 3(Caspase-3)was detected by Western blot.The different concentrations of brucine were observed to explain the effect of breast cancer MDA-MB-231 cells on the expression of apoptosis protein Caspase-3.Results A total of 16 nude mice were successfully modeled,and a long diameter of about 0.5 cm after 16 weeks of subcutaneous injection of breast cancer MDA-MB-231 cells in vivo.One of them was abandoned because of fed and the nutritional status was poor,the remaining 15 nude mice were randomly divided into five groups,and the corresponding treatment.The growth of xenografts after treatment showed that the tumor volume of the high and middle doses of brucine(30,60 mg/kg)and the positive control group(paclitaxel 5 mg/kg)were significantly reduced compared with the negative control group,the difference was statistically significant,but it was no significant difference in the low-dose group(15mg/kg).compared with the positive control group,the negative control group and the low-dose group of brucine were show that the tumor volume increased significantly,but there was no significant difference between the high and middle dose groups of brucine.The results of Ki-67 staining,TUNEL assay and Caspase-3immunohistochemistry in transplanted tumor specimens indicated that the high and middle doses of brucine(30,60 mg/kg)and the positive control group(paclitaxel 5mg/kg)showed significant differences compared with the negative control group,while the low dose group of brucine(15 mg/kg)showed no significant difference.the results of Western blotting in vitro showed that the expression of Caspase-3 protein in the triple negative breast cancer cells treated with brucine at concentrations of 200 and 400 ?g/m L was significantly higher than that of other dose groups and the negative control group,while other concentrations of brucine-treated triple-negative breast cancer cells,Caspase-3 protein expression levels were not significantly different.Conclusion brucine can inhibit the growth of triple-negative breast cancer xenografts in nude mice,and its mechanism may be related to the promotion of apoptosis of triple-negative breast cancer cells. |
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