Studies concerning correlations between pituitary adenomas and cell apoptosis have mainly focused on upstream apoptosis signaling, but seldom on downstream mediators. In the present study, second mitochondria-derived ...Studies concerning correlations between pituitary adenomas and cell apoptosis have mainly focused on upstream apoptosis signaling, but seldom on downstream mediators. In the present study, second mitochondria-derived activator of caspases （Smac）, X-linked inhibitor of apoptosis protein （XIAP）, and caspase-3 protein were qualitatively analyzed using immunohistochemistry, and quantified by western blot. Smac, XIAP, and caspase-3 mRNA expressions were detected by reverse transcription-PCR. Results showed that XIAP protein and mRNA expressions were greater in the invasive pituitary adenoma group compared with the noninvasive pituitary adenoma group. However, Smac and caspase-3 protein and mRNA expressions were lower in the invasive pituitary adenoma group compared with the noninvasive pituitary adenoma group. In the invasive pituitary adenomas, Smac expression was positively correlated with caspase-3 protein and mRNA expression （Protein： r = 0.55, P 0.01; mRNA： r = 0.50, P 0.01）. Smac and caspase-3 expressions were negatively correlated with XIAP protein and mRNA expression （Protein： r = -0.56, -0.64, P 0.01; mRNA： r = -0.69, -0.67, P 0.01）. However, no significant differences in correlation among Smac, XIAP, and caspase-3 were detectable in noninvasive pituitary adenomas. These data indicated that high expression of XIAP and low expression of Smac and caspase-3 suppressed cell apoptosis and led to enhanced invasiveness of pituitary adenomas. Thus, Smac, XIAP, and caspase-3 may be useful markers in determining the invasive behavior of pituitary adenomas.展开更多
Objective： To investigate the relation of X-linked inhibitor of apoptosis （XIAP） and second mitochondria-derived activator of caspase （Smac） signaling pathway to chemoresistance in human pancreatic cancer Panc-1 ...Objective： To investigate the relation of X-linked inhibitor of apoptosis （XIAP） and second mitochondria-derived activator of caspase （Smac） signaling pathway to chemoresistance in human pancreatic cancer Panc-1 and BXPC-3 cells. Methods： Apoptosis and the changes of XIAP expression in permeabilized cells induced by cisplatin and 5-fluorouracil （FU） were measured by flow cytometry. The cytosolic expression of XIAP, Smac and caspase-3 was detected by Western blot. A recombinant plasmid vector pEGFP-N1/Smac was constructed and transfected into of Pancol cells. The effect of cytosolic overexpression of Smac on apoptosis of Panc-1 cells was evaluated by flow cytometry. Results： Panc-1 was more resistant to cisplatin or 5-FU induced apoptosis than BXPC-3. Western blot revealed that chemoresistant Panc-1 highly expressed XIAP, and increased cytosolic expression of Smac might be responsible for the marked down-regulation of XIAP in chemo-sensitive BXPC-3 cells after exposure to cisplatin or 5-FU. Furthermore, cytosolic overexpression of Smac could significantly down-regulate the levels of XIAP and promote the activity of caspase-3, as well as sensitize Panc-1 cells to anticancer drug-induced apoptosis. Conclusion： Anticancer drug-induced apoptosis requires mitochondrial release of Smac and downregulation of XIAP, which may be an important determinant of chemo-sensitivity in pancreatic cancer cells. Up-regulation of cytosolic expression of Smac may act as an effective modifying signal to overcome apoptosis resistance to chemotherapy in pancreatic cancer cells.展开更多
目的:旨在研究血管内皮生长因子(vascular endothelial growth factor,VEGF)和第二线粒体衍生的caspase激活剂(second mitochondrial activator of caspase,Smac)/低等电点凋亡抑制蛋白直接结合蛋白(direct IAP binding protein with lo...目的:旨在研究血管内皮生长因子(vascular endothelial growth factor,VEGF)和第二线粒体衍生的caspase激活剂(second mitochondrial activator of caspase,Smac)/低等电点凋亡抑制蛋白直接结合蛋白(direct IAP binding protein with low PI,DIABLO)在胶质瘤发生和发展中的作用。方法:采用慢病毒介导的RNA干扰技术沉默VEGF基因在胶质瘤细胞U251中的表达;分别采用实时荧光定量PCR(real-time?uorogenic quantitative-PCR,RFQ-PCR)和蛋白质印迹法检测VEGF和Smac/DIABLO mRNA及蛋白在U251细胞中的表达水平;采用蛋白质印迹法检测磷酸化细胞外蛋白调节激酶(extracellular regulated protein kinase,ERK)的表达;FCM检测VEGF沉默对细胞周期的影响;MTT法检测VEGF沉默对U251细胞化疗敏感性的影响。结果:VEGF基因沉默可导致VEGF和Smac/DIABLO mRNA及蛋白表达水平的下调,并抑制磷酸化ERK的表达,提示VEGF是Smac/DIABLO的上游调节因子,通过激活ERK的信号通路调节Smac/DIABLO的表达水平。VEGF基因沉默导致U251细胞中处于S期的细胞比例增多,并增强顺铂对U251细胞的凋亡诱导作用。结论:VEGF可影响胶质瘤细胞周期的分布以及对顺铂的化疗敏感性。Smac/DIABLO参与了VEGF信号通路。展开更多
目的探讨维生素E琥珀酸酯(vitamin E succinate,VES)对人胃癌SGC-7901细胞线粒体凋亡通路中第二种线粒体来源半胱氨酸蛋白酶激活剂(secondmitochondria-derivedactivatorofcaspases,Smac)、X连锁凋亡抑制蛋白(X-linked inhibitor of apo...目的探讨维生素E琥珀酸酯(vitamin E succinate,VES)对人胃癌SGC-7901细胞线粒体凋亡通路中第二种线粒体来源半胱氨酸蛋白酶激活剂(secondmitochondria-derivedactivatorofcaspases,Smac)、X连锁凋亡抑制蛋白(X-linked inhibitor of apoptosis protein,XIAP)基因和蛋白表达的影响及其诱导凋亡机制。方法不同浓度VES(5、10、15、20μg/ml)处理人胃癌细胞24h,0.01%的无水乙醇设为对照组。CCK-8检测细胞增殖活性;实时荧光定量PCR检测线粒体相关凋亡分子Smac、XIAP mRNA表达变化;Western blot检测线粒体相关凋亡分子Smac、XIAP蛋白表达水平的差异;Annexin-V/PI双染流式细胞术检测各组细胞凋亡率。结果与对照组相比,不同浓度VES(5、10、15、20μg/ml)作用胃癌细胞后的细胞增殖率分别为94.67%±0.33%、85.28%±0.82%、67.63%±1.3%、52.11%±2.3%,VES抑制细胞增殖的效果随VES浓度升高而增强(P<0.05);Smac mRNA随着VES剂量的增加而增加(P<0.05),在15μg/ml达到峰值(P<0.05),XIAPmRNA随着VES剂量的增加而下降(P<0.05);XIAP蛋白在5、10μg/mlVES处理组表达量差异无统计学意义,在15、20μg/ml VES处理组,表达量差异有统计学意义(P<0.05),蛋白表达量随着浓度升高(P<0.05),Smac蛋白蛋白表达量随着VES剂量的增加明显升高(P<0.05);不同浓度VES(5、10、15、20μg/ml)处理组凋亡率依次为2.06%±0.21%、8.17%±0.56%、13.30%±0.33%、19.82%±0.95%、34.45%±1.78%,VES诱导细胞凋亡的效果随VES作用浓度升高而升高(P<0.05)。结论VES可以抑制胃癌细胞增殖、诱导细胞凋亡,在转录和翻译水平上上调Smac的表达、抑制XIAP的表达。展开更多
文摘Studies concerning correlations between pituitary adenomas and cell apoptosis have mainly focused on upstream apoptosis signaling, but seldom on downstream mediators. In the present study, second mitochondria-derived activator of caspases （Smac）, X-linked inhibitor of apoptosis protein （XIAP）, and caspase-3 protein were qualitatively analyzed using immunohistochemistry, and quantified by western blot. Smac, XIAP, and caspase-3 mRNA expressions were detected by reverse transcription-PCR. Results showed that XIAP protein and mRNA expressions were greater in the invasive pituitary adenoma group compared with the noninvasive pituitary adenoma group. However, Smac and caspase-3 protein and mRNA expressions were lower in the invasive pituitary adenoma group compared with the noninvasive pituitary adenoma group. In the invasive pituitary adenomas, Smac expression was positively correlated with caspase-3 protein and mRNA expression （Protein： r = 0.55, P 0.01; mRNA： r = 0.50, P 0.01）. Smac and caspase-3 expressions were negatively correlated with XIAP protein and mRNA expression （Protein： r = -0.56, -0.64, P 0.01; mRNA： r = -0.69, -0.67, P 0.01）. However, no significant differences in correlation among Smac, XIAP, and caspase-3 were detectable in noninvasive pituitary adenomas. These data indicated that high expression of XIAP and low expression of Smac and caspase-3 suppressed cell apoptosis and led to enhanced invasiveness of pituitary adenomas. Thus, Smac, XIAP, and caspase-3 may be useful markers in determining the invasive behavior of pituitary adenomas.
基金This work was supported by grants from Foundation of Science and Technology of Shenzhen (No. 200304250).
文摘Objective： To investigate the relation of X-linked inhibitor of apoptosis （XIAP） and second mitochondria-derived activator of caspase （Smac） signaling pathway to chemoresistance in human pancreatic cancer Panc-1 and BXPC-3 cells. Methods： Apoptosis and the changes of XIAP expression in permeabilized cells induced by cisplatin and 5-fluorouracil （FU） were measured by flow cytometry. The cytosolic expression of XIAP, Smac and caspase-3 was detected by Western blot. A recombinant plasmid vector pEGFP-N1/Smac was constructed and transfected into of Pancol cells. The effect of cytosolic overexpression of Smac on apoptosis of Panc-1 cells was evaluated by flow cytometry. Results： Panc-1 was more resistant to cisplatin or 5-FU induced apoptosis than BXPC-3. Western blot revealed that chemoresistant Panc-1 highly expressed XIAP, and increased cytosolic expression of Smac might be responsible for the marked down-regulation of XIAP in chemo-sensitive BXPC-3 cells after exposure to cisplatin or 5-FU. Furthermore, cytosolic overexpression of Smac could significantly down-regulate the levels of XIAP and promote the activity of caspase-3, as well as sensitize Panc-1 cells to anticancer drug-induced apoptosis. Conclusion： Anticancer drug-induced apoptosis requires mitochondrial release of Smac and downregulation of XIAP, which may be an important determinant of chemo-sensitivity in pancreatic cancer cells. Up-regulation of cytosolic expression of Smac may act as an effective modifying signal to overcome apoptosis resistance to chemotherapy in pancreatic cancer cells.
文摘目的:旨在研究血管内皮生长因子(vascular endothelial growth factor,VEGF)和第二线粒体衍生的caspase激活剂(second mitochondrial activator of caspase,Smac)/低等电点凋亡抑制蛋白直接结合蛋白(direct IAP binding protein with low PI,DIABLO)在胶质瘤发生和发展中的作用。方法:采用慢病毒介导的RNA干扰技术沉默VEGF基因在胶质瘤细胞U251中的表达;分别采用实时荧光定量PCR(real-time?uorogenic quantitative-PCR,RFQ-PCR)和蛋白质印迹法检测VEGF和Smac/DIABLO mRNA及蛋白在U251细胞中的表达水平;采用蛋白质印迹法检测磷酸化细胞外蛋白调节激酶(extracellular regulated protein kinase,ERK)的表达;FCM检测VEGF沉默对细胞周期的影响;MTT法检测VEGF沉默对U251细胞化疗敏感性的影响。结果:VEGF基因沉默可导致VEGF和Smac/DIABLO mRNA及蛋白表达水平的下调,并抑制磷酸化ERK的表达,提示VEGF是Smac/DIABLO的上游调节因子,通过激活ERK的信号通路调节Smac/DIABLO的表达水平。VEGF基因沉默导致U251细胞中处于S期的细胞比例增多,并增强顺铂对U251细胞的凋亡诱导作用。结论:VEGF可影响胶质瘤细胞周期的分布以及对顺铂的化疗敏感性。Smac/DIABLO参与了VEGF信号通路。
