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:探讨细胞外基质蛋白1(extracellular matrix protein 1,ECM1)在肿瘤组织中的表达及意义。方法:应用免疫组织化学EnVision法,检测肝脏、乳腺、直肠组织(正常组织和肿瘤组织)中ECM1的表达,比较正常组织和肿瘤组织淋巴结转移肿瘤和淋...目的:探讨细胞外基质蛋白1(extracellular matrix protein 1,ECM1)在肿瘤组织中的表达及意义。方法:应用免疫组织化学EnVision法,检测肝脏、乳腺、直肠组织(正常组织和肿瘤组织)中ECM1的表达,比较正常组织和肿瘤组织淋巴结转移肿瘤和淋巴结未转移肿瘤之间的ECM1表达差异。结果:ECM1的表达如下:正常肝组织阳性率20.0％(4／20),肝癌组织阳性率85.4％(70／82);正常乳腺组织阳性率9.1％(1／11),乳腺癌组织阳性率60.0％(18／30),其中淋巴结(一)者为37.5％(6／16),淋巴结(+)者为85.7％(12／14);正常直肠组织阳性率11.8％(2／17),直肠癌组织阳性率54.5％(18／33),其中淋巴结(一)者为33.3％(6／18),淋巴结(+)者为80.0％(12／15)。统计分析表明,对ECM1的表达,肿瘤组织高于正常组织,淋巴结转移性肿瘤高于非转移性(P<0.01)。结论:ECM1在肿瘤组织中过表达,并且与肿瘤的转移相关。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:探讨细胞外基质蛋白1(extracellular matrix protein 1,ECM1)在肿瘤组织中的表达及意义。方法:应用免疫组织化学EnVision法,检测肝脏、乳腺、直肠组织(正常组织和肿瘤组织)中ECM1的表达,比较正常组织和肿瘤组织淋巴结转移肿瘤和淋巴结未转移肿瘤之间的ECM1表达差异。结果:ECM1的表达如下:正常肝组织阳性率20.0％(4／20),肝癌组织阳性率85.4％(70／82);正常乳腺组织阳性率9.1％(1／11),乳腺癌组织阳性率60.0％(18／30),其中淋巴结(一)者为37.5％(6／16),淋巴结(+)者为85.7％(12／14);正常直肠组织阳性率11.8％(2／17),直肠癌组织阳性率54.5％(18／33),其中淋巴结(一)者为33.3％(6／18),淋巴结(+)者为80.0％(12／15)。统计分析表明,对ECM1的表达,肿瘤组织高于正常组织,淋巴结转移性肿瘤高于非转移性(P<0.01)。结论:ECM1在肿瘤组织中过表达,并且与肿瘤的转移相关。
