Background:XIAP-associated factor 1(XAF1)negatively regulates the function of the X-linked inhibitor of apoptosis protein(XIAP),a member of the IAP family that exerts antiapoptotic effects.The extracellular signal-reg...Background:XIAP-associated factor 1(XAF1)negatively regulates the function of the X-linked inhibitor of apoptosis protein(XIAP),a member of the IAP family that exerts antiapoptotic effects.The extracellular signal-regulated kinase(ERK)pathway is thought to increase cell proliferation and to protect cells from apoptosis.The aim of the study was to investigate the correlation between the ERK1/2 signaling pathway and XAF1 in colon cancer.Methods:Four human colon cancer cell lines,HCT1116 and Lovo(wildtype p53),DLD1 and SW1116(mutant p53),were used.Lovo stable transfectants with XAF1 sense and antisense were established.The effects of dominant-negative MEK1(DN-MEK1)and MEK-specific inhibitor U0126 on the ERK signaling pathway and expression of XAF1 and XIAP proteins were determined.The transcription activity of core XAF1 promoter was assessed by dual luciferase reporter assay.Cell proliferation was measured by MTT assay.Apoptosis was determined by Hoechst 33258 staining.Results:U0126 increased the expression of XAF1 in a time-and dose-dependent manner.A similar result was obtained in cells transfected with DN-MEK1 treatment.Conversely,the expression of XIAP was down-regulated.Activity of the putative promoter of the XAF1 gene was significantly increased by U0126 treatment and DN-MEK1 transient transfection.rhEGF-stimulated phosphorylation of ERK appeared to have little or no effect on XAF1 expression.Overexpression of XAF1 was more sensitive to U0126-induced apoptosis,whereas down-regulation of XAF1 by antisense reversed U0126-induced inhibition of cell proliferation.Conclusions:XAF1 expression was up-regulated by inhibition of the ERK1/2 pathway through transcriptional regulation,which required de novo protein synthesis.The results suggest that XAF1 mediates apoptosis induced by the ERK1/2 pathway in colon cancer.展开更多
目的:研究支气管哮喘不同时期细胞外信号调节激酶(External signal regulated kinase,ERK)的磷酸化与c-Fos表达,以探讨ERK信号转导途径在支气管哮喘气道重塑中的作用。方法:复制大鼠哮喘模型,随机分为对照组(包括4周、8周及12周对照组)...目的:研究支气管哮喘不同时期细胞外信号调节激酶(External signal regulated kinase,ERK)的磷酸化与c-Fos表达,以探讨ERK信号转导途径在支气管哮喘气道重塑中的作用。方法:复制大鼠哮喘模型,随机分为对照组(包括4周、8周及12周对照组)、哮喘组(包括4周、8周及12周哮喘组),图像分析软件测定支气管壁厚度(Wat)和平滑肌厚度(Wam),免疫组化测定肺组织磷酸化的ERK(Phospho-ERK,P-ERK)与c-Fos表达,免疫印迹法测定磷酸化的ERK水平,直线相关分析法显示Wat和Wam与P-ERK的相关性。结果:各哮喘组Wat和Wam,P-ERK和c-Fos的平均吸光度均显著高于相应对照组(P均<0.01);各哮喘组磷酸化的ERK水平均显著高于相应对照组(其中A12也与C8组比)(P<0.01);Wat、Wam与P-ERK平均吸光度均呈显著正相关性(P<0.01)。结论:ERK磷酸化水平和c-Fos在哮喘大鼠均增加,ERK信号转导途径在支气管哮喘气道重塑中起重要作用。展开更多
目的：探讨细胞外信号调节蛋白激酶（ERK）通路在慢性哮喘大鼠气道平滑肌细胞（ASMC）凋亡中的作用及其机制。方法：30只Wistar大鼠分为正常对照组（A组）和慢性哮喘组（B组），用原位末端标记法和Annexin—V FIT CPI双染色法观察ASMC...目的：探讨细胞外信号调节蛋白激酶（ERK）通路在慢性哮喘大鼠气道平滑肌细胞（ASMC）凋亡中的作用及其机制。方法：30只Wistar大鼠分为正常对照组（A组）和慢性哮喘组（B组），用原位末端标记法和Annexin—V FIT CPI双染色法观察ASMC凋亡，免疫组织化学法检测bcl-2和bax的表达，Western blot检测caspase-3蛋白的表达，并用ERK激动剂表皮生长因子（EGF）和抑制剂PD98059干预两组ASMC，观察上述指标的变化。结果：与正常对照组ASMC比较，慢性哮喘组ASMC凋亡指数、早期凋亡细胞百分率明显下降。经PD98059干预之后，慢性哮喘组ASMC的凋亡指数与早期凋亡细胞百分率、bax蛋白表达量和caspase-3蛋白含量明显增高，bcl-2蛋白表达量明显降低。经EGF干预之后，慢性哮喘组ASMC凋亡指数与早期凋亡细胞百分率进一步下降，而这一作用可以被PD98059所抑制。结论：慢性哮喘组大鼠ASMC内源性增殖活性增加的同时，伴有凋亡活性下降。ERK1／2参与慢性哮喘ASMC凋亡调控，其机制与bcl-2家族和caspace-3有关。展开更多
基金Shanghai Medical Key Discipline Construction Foundation(05-Ⅲ-005-017).
文摘Background:XIAP-associated factor 1(XAF1)negatively regulates the function of the X-linked inhibitor of apoptosis protein(XIAP),a member of the IAP family that exerts antiapoptotic effects.The extracellular signal-regulated kinase(ERK)pathway is thought to increase cell proliferation and to protect cells from apoptosis.The aim of the study was to investigate the correlation between the ERK1/2 signaling pathway and XAF1 in colon cancer.Methods:Four human colon cancer cell lines,HCT1116 and Lovo(wildtype p53),DLD1 and SW1116(mutant p53),were used.Lovo stable transfectants with XAF1 sense and antisense were established.The effects of dominant-negative MEK1(DN-MEK1)and MEK-specific inhibitor U0126 on the ERK signaling pathway and expression of XAF1 and XIAP proteins were determined.The transcription activity of core XAF1 promoter was assessed by dual luciferase reporter assay.Cell proliferation was measured by MTT assay.Apoptosis was determined by Hoechst 33258 staining.Results:U0126 increased the expression of XAF1 in a time-and dose-dependent manner.A similar result was obtained in cells transfected with DN-MEK1 treatment.Conversely,the expression of XIAP was down-regulated.Activity of the putative promoter of the XAF1 gene was significantly increased by U0126 treatment and DN-MEK1 transient transfection.rhEGF-stimulated phosphorylation of ERK appeared to have little or no effect on XAF1 expression.Overexpression of XAF1 was more sensitive to U0126-induced apoptosis,whereas down-regulation of XAF1 by antisense reversed U0126-induced inhibition of cell proliferation.Conclusions:XAF1 expression was up-regulated by inhibition of the ERK1/2 pathway through transcriptional regulation,which required de novo protein synthesis.The results suggest that XAF1 mediates apoptosis induced by the ERK1/2 pathway in colon cancer.
文摘目的:研究支气管哮喘不同时期细胞外信号调节激酶(External signal regulated kinase,ERK)的磷酸化与c-Fos表达,以探讨ERK信号转导途径在支气管哮喘气道重塑中的作用。方法:复制大鼠哮喘模型,随机分为对照组(包括4周、8周及12周对照组)、哮喘组(包括4周、8周及12周哮喘组),图像分析软件测定支气管壁厚度(Wat)和平滑肌厚度(Wam),免疫组化测定肺组织磷酸化的ERK(Phospho-ERK,P-ERK)与c-Fos表达,免疫印迹法测定磷酸化的ERK水平,直线相关分析法显示Wat和Wam与P-ERK的相关性。结果:各哮喘组Wat和Wam,P-ERK和c-Fos的平均吸光度均显著高于相应对照组(P均<0.01);各哮喘组磷酸化的ERK水平均显著高于相应对照组(其中A12也与C8组比)(P<0.01);Wat、Wam与P-ERK平均吸光度均呈显著正相关性(P<0.01)。结论:ERK磷酸化水平和c-Fos在哮喘大鼠均增加,ERK信号转导途径在支气管哮喘气道重塑中起重要作用。
文摘目的：探讨细胞外信号调节蛋白激酶（ERK）通路在慢性哮喘大鼠气道平滑肌细胞（ASMC）凋亡中的作用及其机制。方法：30只Wistar大鼠分为正常对照组（A组）和慢性哮喘组（B组），用原位末端标记法和Annexin—V FIT CPI双染色法观察ASMC凋亡，免疫组织化学法检测bcl-2和bax的表达，Western blot检测caspase-3蛋白的表达，并用ERK激动剂表皮生长因子（EGF）和抑制剂PD98059干预两组ASMC，观察上述指标的变化。结果：与正常对照组ASMC比较，慢性哮喘组ASMC凋亡指数、早期凋亡细胞百分率明显下降。经PD98059干预之后，慢性哮喘组ASMC的凋亡指数与早期凋亡细胞百分率、bax蛋白表达量和caspase-3蛋白含量明显增高，bcl-2蛋白表达量明显降低。经EGF干预之后，慢性哮喘组ASMC凋亡指数与早期凋亡细胞百分率进一步下降，而这一作用可以被PD98059所抑制。结论：慢性哮喘组大鼠ASMC内源性增殖活性增加的同时，伴有凋亡活性下降。ERK1／2参与慢性哮喘ASMC凋亡调控，其机制与bcl-2家族和caspace-3有关。
