Axin1调节骨骼肌GLUT4蛋白表达的作用研究

目的：探讨体轴发育抑制因子（Axin1）调节骨骼肌葡萄糖转运蛋白4(GLUT4)蛋白表达的作用及其机制。方法：利用RNAi干扰的Axin1腺病毒（Ad-siAxin1）感染C2C12小鼠骨骼肌细胞敲低Axin1,荧光显微镜和MTS实验明确Ad-siAxin1最佳感染浓度和时间。分别用携带绿色荧光蛋白的腺病毒（Ad-GFP）、Ad-siAxin1、载体质粒（vector）和Axin1质粒转染C2C12小鼠骨骼肌细胞敲低或过表达Axin1蛋白,Western印迹检测Axin1、端锚聚合酶蛋白（TNKS）和GLUT4蛋白水平。结果：荧光显微镜和MTS实验结果显示,在C2C12小鼠骨骼肌细胞中Ad-siAxin1作用的最佳浓度和时间分别为160μL和48 h。Western印迹结果显示,与Ad-GFP组相比,Ad-siAxin1组中Axin1蛋白降低（t=6.746,P<0.01）。Ad-siAxin1组TNKS蛋白水平降低（t=4.019,P<0.05）,GLUT4蛋白水平下调（t=3.248,P<0.05）。与vector组相比,转染Axin1质粒后,Axin1蛋白水平上...     

Atonal homolog 1 expression in lung cancer correlates with inhibitors of the Wnt pathway as well as the differentiation and primary tumor stage

Atonal homolog 1 (Atoh1) is crucial to the differentiation of many cell types and participates in tumorigenesis and progression. This study investigated the role of Atoh1 in lung cancer development and its correlation with key members of the Wnt pathway. We used immunohistochemistry to examine the expressions of Atoh1, β‐catenin, Axin, chibby, and Disabled‐2 (Dab2) in 118 samples of lung cancer. We also detected the cytoplasmic and nuclear expression of Atoh1 in lung cancer tissues using western blot. Atoh1 nuclear expression was negatively correlated with differentiation level (p = 0.004) and primary tumor stage (p = 0.044) of lung cancer. Nuclear Atoh1 expression was positively correlated with nuclear expression of chibby (p < 0.001) and Dab2 (p < 0.001). Cytoplasmic Atoh1 expression was positively correlated with the cytoplasmic expression of Axin (p = 0.028), chibby (p < 0.001), and Dab2 (p < 0.001). We conclude that the nuclear expression of Atoh1 was inversely correlated with the differentiation and primary tumor stage of lung cancers. The expression and localization of Atoh1 correlated with Axin, chibby, or Dab2. Atoh1 may be a potential therapeutic target for the inhibition of growth and progression of lung cancers.     

Preserved Axin expression is associated with an aggressive phenotype in invasive breast carcinomas

Reduced Axin expression has been associated with an aggressive behavior in lung and esophageal squamous cell carcinomas. Its role in breast cancer has not been defined. The aim of our study was to investigate the expression pattern of Axin protein in invasive breast carcinomas, in relation to the behavior and prognosis of the disease. Immunohistochemistry was performed for the detection of Axin expression in 232 breast cancer tissues. Univariate and multivariate statistical analyses were used to assess the relation of Axin expression with classic clinicopathological parameters, patients' survival and various biologic markers Human Epidermal Factor‐2 (HER‐2), Ki‐67, topoIIα, glycogen synthase kinase‐3β (GSK‐3β)]. Preserved cytoplasmic Axin expression was positively correlated to lymph node invasion, HER‐2 and GSK‐3β and inversely to Ki‐67 and topoIIα. Nuclear Axin was positively associated with tumor size. Stromal Axin showed a parallel association with lymph node status and HER‐2. In the subgroup of lobular breast carcinomas, preserved Axin was found to exert an unfavorable impact on patients' overall survival. Our findings indicate, for the first time, that in invasive breast cancer preserved Axin expression is associated with a more aggressive phenotype and that in the discrete subtype of lobular breast carcinomas Axin negatively influences patients' overall survival.     

V806M突变型Axin基因真核表达载体的构建及其在神经胶质细胞瘤内的表达

目的构建V806M突变型Axin基因真核表达载体pIRES2-EGFP-MT-Axin(V806M),并稳定表达于大鼠神经胶质瘤细胞系C6。方法用分子克隆技术,构建真核表达载体pIRES2-EGFP-MT-Axin(V806M),经NheⅠ和SmaⅠ双酶切鉴定后,用脂质体法稳定转染神经胶质瘤细胞C6。结果构建了真核表达载体pIRES2-EGFP-MT-Axin(V806M),稳定转染后,经荧光显微镜和免疫细胞化学染色法检测,可见细胞内有EGFP及Axin的表达。结论成功构建真核表达载体pIRES2-EGFP-MT-Axin(V806M),并在神经胶质瘤细胞C6中表达,为研究此种突变体Axin是否影响细胞的生物学行为以及是否参与胶质瘤的发生发展奠定了实验基础。     

结直肠腺瘤组织Axin2和Cyclin D1表达及其生物学意义的研究

目的:探讨结直肠隆起型腺瘤和平坦型腺瘤组织Axin 2和Cyclin D1的表达情况。方法:收集64例结直肠隆起型腺瘤和47例结直肠平坦型腺瘤的活检组织标本,统计其临床病理资料,采用免疫组化检测各标本中Axin 2和Cyclin D1蛋白的表达情况。结果:在平坦型腺瘤中Axin 2的表达明显弱于隆起型腺瘤中的表达,而平坦型腺瘤组织Cy-clin D1的表达强于隆起型腺瘤组织CyclinD1的表达(Axin 2:z=-2.390,P=0.017;Cyclin D1:z=-3.103,P=0.002)。结论:结直肠平坦型腺瘤组织Axin 2和Cyclin D1的表达情况与隆起型腺瘤比较差异有统计学意义,提示结直肠平坦型腺瘤发生发展的机制不同于隆起型腺瘤。     

黑斑息肉综合征中Axin表达研究

目的研究Axin在结直肠腺癌、结直肠腺瘤、黑斑息肉综合征(PJS)息肉及正常结直肠黏膜组织中的表达,探讨其在PJS息肉演变中的作用。方法随机选取手术中切除的正常结直肠黏膜、PJS息肉、结直肠腺瘤息肉和结直肠腺癌组织标本各32份,采用免疫组织化学方法分别检测不同组织中Axin蛋白的表达与分布;反转录聚合酶链反应(RT-PCR)检测各组织(各16份)标本中Axin mRNA的表达,并比较其表达水平的差异。结果上述各种组织中,Axin蛋白阳性表达均位于胞质,阳性表达强度以正常结直肠黏膜组织最强,结直肠腺癌组织最弱,各组差异具有显著性(P<0.05);RT-PCR所得产物电泳后经Image-Pro Plus软件分析,得到各组织中Axin基因积分光密度值(IOD)/内参IOD值(Axin IOD/GAPDH IOD):正常结直肠黏膜组织为0.991±0.120,PJS息肉组织为0.794±0.119,结直肠腺瘤组织为0.598±0.116,结直肠腺癌组织为0.313±0.087,不同组织的Axin mRNA表达水平有显著性差异(P<0.05)。结论正常结直肠黏膜、PJS息肉、结直肠腺瘤、和结直肠腺癌组织中Axin mRNA及蛋白表达水平呈依次减弱趋势,与其病理改变程度呈负性相关,PJS息肉中Axin的表达变化可能是PJS发生和演变的特征之一。     

Mutations of the APC,beta-catenin,and axin 1 genes and cytoplasmic accumulation of beta-catenin in oral squamous cell carcinoma

Purpose: The Wnt pathway is involved in carcinogenesis and three regulatory genes of the Wnt pathway, APC, beta-catenin and Axin are mutated in some primary human cancers. Mutations in these genes can impair the down regulation of beta-catenin, which results in the stabilization of beta-catenin, accumulation of free beta-catenin and subsequent activation of the Wnt pathway. To clarify the genetic alterations of components of the Wnt pathway in oral squamous cell carcinoma (SCC), we examined mutations in the APC, beta-catenin and Axin genes and subcellular localization of beta-catenin. Methods: 20 oral SCC tissues and four cell lines derived from oral SCC were used. Mutational analysis was performed by a single-strand conformation polymorphism (SSCP) method and direct sequecing analysis. The samples were also examined by immunohistochemical staining and immunoblot analysis. Results: In 3 of 4 cell lines, mutations were observed in the APC and Axin1 genes without amino acid substitutions. In a clinical sample, a mutation in the Axin1 gene was detected; a T insertion at codon 250 resulted in the formation of a stop codon at codon 259. In addition, cytoplasmic accumulation of beta-catenin was observed in 3 (75%) of 4 cell lines and 18 (90%) of 20 cancer tissue samples. Conclusion: The Axin1 gene may be one of the mutational target in oral SCC. In addition, the cytoplasmic accumulation of beta-catenin is a common characteristic of oral SCC, but is not closely associated with mutational alterations in the APC, beta-catenin and Axin1 genes.