异甘草素对小鼠乳腺癌移植瘤的抑制作用研究

Study on the inhibitory effect of isoliquiritin on transplanted breast cancer tumor in mice

目的探究异甘草素对小鼠乳腺癌移植瘤的抑制作用及其作用机制。方法将40只成功构建乳腺癌移植瘤的小鼠随机分为对照组和低、中、高剂量实验组(分别灌胃给予10、20、40 mg·kg^(-1)异甘草素),每组10只,共给药10 d。每隔7 d用游标卡尺测量肿瘤大小,并计算肿瘤体积,28 d后处死小鼠取肿瘤组织称重后,用免疫组化法检测肿瘤组织中血管内皮生长因子(VEGF)的表达,用原位末端标记(TUNEL)法检测肿瘤细胞凋亡情况,用蛋白质印迹法检测B细胞淋巴瘤-2相关X蛋白(Bax)、裂解的胱天蛋白酶-3(Cl-caspase-3)、上皮细胞钙黏蛋白(E-cadherin)、N-钙黏蛋白(N-cadherin)、Notch1蛋白(Notch1)、发状分裂相关增强子1(Hes1)蛋白的表达水平。结果对照组和低、中、高剂量实验组的28 d肿瘤体积分别为(895.62±65.14)、(701.19±46.33)、(495.67±51.40)和(408.96±30.62)mm^(3),抑瘤率分别为0、(13.17±6.94)%、(35.33±10.38)%和(43.84±4.96)%,VEGF平均光密度值分别为74.90±8.08、59.86±5.63、50.80±2.99和39.15±3.73,细胞凋亡率分别为(3.44±0.27)%、(10.34±0.96)%、(14.60±1.48)%和(21.34±2.15)%,Bax蛋白相对表达水平分别为0.46±0.03、0.61±0.05、0.68±0.06和0.91±0.08,E-cadherin蛋白相对表达水平分别为0.35±0.04、0.51±0.06、0.66±0.08和0.92±0.06,Notch1蛋白相对表达水平分别为0.88±0.10、0.73±0.08、0.58±0.07和0.49±0.05。低、中、高剂量实验组的上述指标与对照组比较,差异均有统计学意义(均P<0.05);中、高剂量实验组的上述指标与低剂量实验组比较,中剂量实验组的上述指标与高剂量实验组比较,差异均有统计学意义(均P<0.05)。结论异甘草素可显著抑制乳腺癌小鼠肿瘤生长及上皮间质转化,这可能与抑制Notch1通路有关。

Objective To investigate the effect and mechanism of isoliquiritin on radiotherapy sensitization of breast cancer through in vivo experiments.Methods A total of 40 mice with successfully constructed breast cancer transplant tumor were randomly divided into control group and low,medium,high dose experimental groups(10,20,40 mg·kg^(-1) isoliquiritin by gavage),10 mice in each group,for 10 d.The tumor size was measured with vernier caliper every 7 d,and the tumor volume was calculated.After 28 days,the mice were sacrificed,the tumor tissues were weighed,and the expression of vascular endothelial growth factor(VEGF)in the tumor tissues was detected by immunohistochemistry.Terminal-deoxynucleoitidyl transferase mediated nick end labeling(TUNEL)method was used to detect the apoptosis of tumor cells.B cell lymphoma 2 associated X protein(Bax),cleaved cysteine aspartate proteinase-3(Cl-caspase-3),E-cadherin,N-cadherin,Notch1 and hair division associated enhancer1(Hes1)protein expression levels were detected by Western blot.Results The tumor volumes at 28 days in control group and low,medium,high dose experimental groups were(895.62±65.14),(701.19±46.33),(495.67±51.40),(408.96±30.62)mm^(3);the inhibitory rates were 0,(13.17±6.94)%,(35.33±10.38)%,(43.84±4.96)%;the average optical density of VEGF were 74.90±8.08,59.86±5.63,50.80±2.99,39.15±3.73;the apoptosis rates were(3.44±0.27)%,(10.34±0.96)%,(14.60±1.48)%,(21.34±2.15)%;Bax protein expression levels were 0.46±0.03,0.61±0.05,0.68±0.06,0.91±0.08;the expression levels of E-cadherin protein were 0.35±0.04,0.51±0.06,0.66±0.08,0.92±0.06;the expression levels of Notch1 protein were 0.88±0.10,0.73±0.08,0.58±0.07 and 0.49±0.05,respectively.For the above indexes,low,medium,high dose experimental groups compared with control group,the differences were statistically significant(all P<0.05);the medium,high dose experimental groups compared with low dose experimental group,the differences were statistically significant(all P<0.05);medium dose experimental group compared with high dose experimental group,the differences were statistically significant(all P<0.05).Conclusion Isoliquiritin can significantly inhibit tumor growth and epithelial mesenchymal transformation in breast cancer mice,which may be related to the inhibition of Notch1 pathway.