目的 探讨大黄素对K562细胞裸鼠移植瘤的生长抑制作用及其与Caspase-3和Caspase-9表达变化的关系。方法 建立裸鼠K562细胞皮下移植瘤模型,随机分为大黄素低、中、高剂量(25、50、100mg/kg)3个实验组,以及模型组和羟基脲(120mg/kg)阳性对照组,每组5只,ip连续给药12d,测量各组裸鼠肿瘤体积,称取瘤体质量,计算抑瘤率。采用HE染色光镜和透射电镜观察肿瘤细胞的凋亡情况,应用RT-PCR检测肿瘤组织中caspase-3和caspase-9mRNA表达水平。Western blotting法检测肿瘤组织中proCaspase-3和proCaspase-9蛋白的表达。结果 大黄素低、中、高剂量组肿瘤相对体积(RTV)分别为5.23±0.24、4.38±0.17、3.57±0.31;与模型组(10.45±0.47)相比,大黄素处理组肿瘤体积明显缩小,具有统计学意义(P<0.01)。光镜和电镜结果表明大黄素能够诱导K562细胞发生明显的凋亡。RT-PCR结果表明不同剂量的大黄素能够引起caspase-3和caspase-9mRNA的表达上调且有剂量依赖性。与模型组相比,大黄素处理组的proCaspase-3和proCaspase-9蛋白均出现明显的下调。结论 大黄素能够明显抑制人K562细胞裸鼠移植瘤的生长,其机制可能与激活Caspase-3和Caspase-9信号转导通路有关。

Objective To explore the inhibitory effects of emodin on xenografted human K562 cells in BALB/c nude mice and its relationship with the expression of Caspase-3 and Caspase-9.Methods The subcutaneously transplanted tumor models of human K562 cells in nude mice were established and then were divided randomly into five groups,including emodin(25,50,and 100 mg/kg),negative control,and hydroxy urine group(120 mg/kg),each of which was composed of five nude mice and then received ip injection in the following 12 d.All mice were sacrificed,tumor volume was measured,and then the weights of tumors were recorded.And the tumor inhibition rate was calculated.Apoptosis morphological transformation of K562 cells induced by emodin was detected by transmission electron microscope and HE staining.RT-PCR was used to detect the expression of caspase-3 and caspase-9 mRNA.Expression of proCaspase-3 and proCaspase-9 protein was determined by Western blotting analysis.Results The relative tumor volume(RTV)was significantly lower in low,moderate,and high dose emodin than that in the negative control group.Compared to negative control group(5.23±0.24,4.38±0.17,and 3.57±0.31 vs 10.45±0.47,P0.01).All the emodin treatment groups showed more obvious inhibition rate(P0.05).Apoptosis and necrosis of tumor cells were found in emodin-treated groups under the light and electron microscope.The results of RT-PCR indicated emodin up-regulated the expression of caspase-3 and caspase-9 mRNA in a dose-dependent manner.Compared with negative control group,the expression of proCaspase-3 and proCaspase-9 protein was down-regulated by emodin at different dosages.Conclusion Emodin could significantly inhibit the growth of K562 cells xenografts in nude mice.The mechanism may be correlated to activate the Caspase-3 and Caspase-9 signaling pathway.

国家自然科学基金资助项目(30300449)；国家中医药管理局资助项目(02-03ZP52)；重庆医科大学校级课题(XBYB2007108)