大豆异黄酮诱导小鼠肝癌移植瘤细胞凋亡的机制

Pro-apoptotic Mechanism of Soy Isoflavones on Transplanted Hepatoma Cells in Mice

目的:探讨大豆异黄酮对小鼠肝癌移植瘤细胞凋亡的诱导机制。方法:建立小鼠H22肝癌皮下移植瘤模型,分为模型组、大豆异黄酮组和5-氟尿嘧啶组。采用DNA ladder法检测移植瘤细胞凋亡情况,蛋白印迹法检测移植瘤组织含半胱氨酸的天冬氨酸蛋白水解酶(cysteinyl aspartate specific proteinase,Caspase)-3、Caspase-8、Caspase-9、B细胞淋巴瘤/白血病-2(B cell lymphoma/lewkmia-2,Bcl-2)、Bcl-2相关X蛋白(Bcl-2-associated X protein,Bax)、细胞色素c(cytochrome c,Cyt c)、细胞凋亡诱导因子(apoptosis inducing factor,AIF)、p53、Survivin和信号传导子及转录激活子(signal transducer and activator of transcription,STAT)3表达情况。结果:与模型组比较,大豆异黄酮组移植瘤质量减轻;肿瘤细胞凋亡特征性DNA片段增多;移植瘤细胞Caspase-3、Caspase-8和Caspase-9的活性片段增多;Bcl-2蛋白相对表达量降低,Bax蛋白相对表达量升高;胞浆Cyt c和AIF水平升高。同时,大豆异黄酮上调移植瘤组织p53蛋白表达,下调STAT3活化和Survivin蛋白表达。结论:大豆异黄酮诱导H22移植瘤细胞凋亡,其促凋亡机制可能与p53和STAT3有关。

Objective:To investigate the pro-apoptotic mechanism of soy isoflavones on transplanted H22 hepatoma cells in mice.Methods:Kunming mice were subcutaneously inoculated with mouse hepatoma H22 cells and then divided into model,soy isoflavone-treated and 5-fuorouracil-treated groups.The apoptosis of transplanted tumor tissue was detected by DNA ladder assay,and the expressions of cysteinyl aspartate specific proteinase(caspase)-3,caspase-8,caspase-9,B cell lymphoma/lewkmia-2(Bcl-2),Bcl-2-associated X protein(Bax),cytochrome c(Cyt c),apoptosis-inducing factor(AIF),p53,survivin and signal transducer and activator of transcription(STAT)3 proteins were detected by Western blotting.Results:Compared with the model group,the growth of transplanted tumor was suppressed,and the intensity of DNA ladder was increased;the active fragments of caspase-3,caspase-8 and caspase-9 were increased;the expression of Bcl-2 protein was decreased,while the expression of Bax was increased;and the cytoplasmic levels of Cyt c and AIF in transplanted tumor tissue were elevated in the soy isoflavone group.In addition,soy isoflavone treatment elevated p53 protein expression,and reduced STAT3 activation and survivin protein expression in transplanted tumor tissue.Conclusion:Soy isoflavones can induce the apoptosis of H22 transplanted tumor cells,and the pro-apoptotic mechanism may be related to the regulation of p53 and STAT3.