Wnt/beta-catenin 信号通路相关蛋白在胃癌组织中的表达和 肿瘤转移的关系

目的：探讨了Wnt信号通路相关蛋白在胃癌组织中的表达及与肿瘤转移的关系。方法：选取2011 年6 月到2012 年6 月我 院胃癌术后47 例肿瘤标本作为研究对象,并选取同一患者的正常胃组织作为对照研究。采用实时荧光定量PCR 和Western blot 对胃癌组织和正常胃组织Wnt 信号通路相关蛋白进行分析,并分析了肿瘤转移和非转移患者Wnt信号通路相关蛋白的变化。结 果：与正常胃组织比较,胃癌组织中Wnt1、Wnt3、Wnt3a、beta-catenin、CyclinD1 和c-Myc 等分子的mRNA 水平明显上调,差异有显 著统计学意义（P<0.05）。胃癌组织中总beta-catenin 和核内beta-catenin蛋白较正常胃组织明显增加,而磷酸化beta-catenin 较正常组明显 下降、差异有显著统计学意义（P<0.05）。与非转移组比较,转移组患者胃癌组织中Wnt1、Wnt3、Wnt3a 等分子mRNA水平显著上 调,差异有统计学意义（P<0.05）。结论：Wnt信号通路异常激活在胃癌发生和癌细胞转移中发挥着重要的作用,为临床治疗提供了 一定靶点。     

跑台运动和饮食控制对去卵巢肥胖大鼠心肌Wnt/β-catenin信号通路的影响

目的:观察跑台运动和饮食控制对去卵巢肥胖大鼠心肌Wnt/β-catenin信号通路中β-catenin、磷酸化-GSK-3β和GSK-3β蛋白表达的影响。方法:将48只3月龄雌性未孕SD大鼠按体重分层后随机分为假手术组、去卵巢组、去卵巢运动组和去卵巢控食组。去卵巢运动组大鼠在去卵巢手术后的第3周开始进行为期8周的跑台运动训练,去卵巢控食组在去卵巢后的第三周开始进行为期8周的控食干预。干预结束后,腹主动脉取血处死各组大鼠,用电子天平秤量大鼠心肌重量,用Western blot方法检测心肌β-catenin、磷酸化-GSK-3β和GSK-3β蛋白表达。结果:与假手术组大鼠比较,去卵巢组大鼠体重、心肌重量显著增加,而心肌重量指数、β-catenin、磷酸化GSK-3β和p-GSK-3β/GSK-3β蛋白表达均显著降低(P0.05);与去卵巢组大鼠比较,去卵巢运动组大鼠在最后两周时体重显著降低(P0.05),心肌组织β-catenin、p-GSK-3β和p-GSK-3β/GSK-3β蛋白表达均显著升高,而去卵巢控食组大鼠体重、心肌重量、心肌重量指数和GSK-3β表达差异均无统计学意义(P0.05),但心肌组织β-catenin、p-GSK-3β和p-GSK-3β/GSK-3β蛋白表达均显著升高(P0.05)。结论:跑台运动和控食干均预均能激活去卵巢大鼠心肌Wnt/β-catenin信号通路。     

单功能烷化剂MNNG对人胃粘膜上皮GES-1细胞的损伤及其对Wnt/β-catenin信号通路的影响

本文旨在从Wnt/β-catenin信号通路的角度探讨单功能烷化剂MNNG诱导人胃粘膜上皮GES-1细胞损伤的机制。用MNNG(2×10-5 mol/L)处理GES-1细胞24 h,处理后第3天用倒置显微镜对GES-1细胞形态进行观察,用MTT法检测GES-1细胞活力,用流式细胞术检测GES-1细胞凋亡和周期变化,用q PCR检测GES-1细胞中β-catenin、GSK-3β、c-Met和MMP7m RNA表达情况,用Western blot检测β-catenin、GSK-3β、p-GSK-3β和c-Met蛋白表达情况。结果显示:MNNG能够明显损伤GES-1细胞,细胞形态变为不规则的长梭形;MNNG能够诱导GES-1细胞凋亡,明显阻滞细胞周期进程;MNNG能够上调β-catenin、GSK-3β、c-Met和MMP7 m RNA表达水平,并上调β-catenin、GSK-3β和p-GSK-3β蛋白表达水平。上述结果提示,MNNG对GES-1细胞的损伤可能与Wnt/β-catenin信号通路的激活相关,这为胃粘膜损伤的细胞模型研究提供了参考。     

飞燕草素通过Wnt/β-catenin信号通路抑制乳腺癌的机制研究

为研究飞燕草素对乳腺癌MDA-MB-231细胞Wnt/β-catenin信号通路的影响。免疫组化检测裸鼠乳腺肿瘤组织和肺组织转移瘤Ki-67及乳腺肿瘤组织蛋白水解酶超家族基质金属蛋白酶-7(matrix metallopeptidase 7,MMP-7)的表达水平;Western blot检测移植瘤Wnt/β-catenin通路β-联蛋白(β-catenin)、磷酸糖原合成酶激酶-3β(glycogen synthase kinase-3β,GSK-3β)及通路下游细胞周期相关蛋白cyclinD1、原癌基因c-myc和MMP-7的蛋白水平表达,体内外实验发现飞燕草素不仅能抑制裸鼠异种移植瘤生长及乳腺癌肿瘤组织和肺组织转移瘤Ki-67表达还可以明显降低乳腺癌MDA-MB-231细胞Wnt/β-catenin信号通路β-catenin和p-GSK-3β下游靶基因c-myc、cyclin D1和MMP-7蛋白的表达。本研究证实飞燕草素能通过抑制Wnt/β-catenin信号通路,发挥抑制乳腺癌的作用。     

beta-catenin 基因在人骨肉瘤MG63 细胞系的表达变化

目的：观察分析beta-catenin 基因在人骨肉瘤MG63 细胞系的表达变化。方法：培养MG63 细胞株,用不同浓度的Wnt3a 蛋白或 相同浓度、不同时间段的Wnt3a 蛋白刺激液MG63细胞生长,用FQ-PCR在mRNA 水平检测beta-catenin 在MG63 细胞系的表达 变化。培养MG63 细胞株,用相同浓度的Wnt3a 蛋白刺激,比较刺激组与空白对照组的细胞数目的差别。结果：在细胞生长的第 0,1 天两组的MG63 细胞数量对比没有统计学差异（P＞0.05）;而在第2,3,4 天对照组细胞增殖速度较刺激组缓缓,经比较（t=4. 109,3.892,5.215,均P＜0.05）。beta-catenin 基因表达不会因为Wnt3a 的浓度增加而增加。100 ng/mL的Wnt3a 蛋白刺激beta-catenin 基 因表达最高,其他几个浓度的beta-catenin 基因表达对比没有统计学差异（P>0.05）。在100 ng/mL的Wnt3a蛋白刺激下,beta-catenin 基 因表达会随时间延长而增加,6 h时茁-catenin基因表达最高（P<0.05）,随后茁-catenin基因表达则没有统计学差异（P>0.005）。结 论：Wnt蛋白对MG63 细胞有正向增加增殖作用。激活Wnt/beta-catenin 信号通路能促进MG63 的细胞增殖。     

Wnt信号通路对成纤维细胞Rat-1生长及表型的调控

构建Wnt-3a的真核表达拽体并稳定转染人鼠成纤维细胞Rat-1,建立Wnt信号通路持续激活的细胞模型,以探讨Wnt信号通路激活对咳细胞的牛K以及某些表型特征的影响。结果表明：Wnt信号通路持续激活时,Rat-1细胞形态表现为细胞长度的增加,其折光性以及呈绳索状的成束密集排布：MTT以及流式细胞仪检测表明稳定转染后细胞增殖率明显高于正常对照组,进入G2期的细胞增多,细胞增殖分裂能力增强：Transwell小窄迁移实验证实转染组的细胞迁移率略高于对照组,但无显著性差异;体外划痕实验表明,稳定转染后的Rat-1细胞在划痕后伤口愈合时问显著缩短。结果提示：体外Wnt信号通路的激沂能够引起成纤维细胞某些表型改变,并促进细胞增殖,加速体外伤口的修复。     

miRNA-95靶向FOXD1基因对结直肠癌LoVo细胞放射敏感性的影响及其机制

目的:探讨miRNA-95靶向FOXD1基因对结直肠癌loVo细胞放射敏感性的影响及其机制。方法:结直肠癌LoVo细胞购自武汉普诺赛生命科技有限公司,将LoVo细胞分为三组接种于6孔板中,每组3个复孔,实验重复3次,C组(对照组正常LoVo细胞),M组(miRNA-95-mimics转染LoVo细胞),I组(miRNA-95-inhibitions转染LoVo细胞),利用直线加速器6 MV/8 Gy的X射线垂直照射细胞,剂量率3 Gy/min,持续照射12 h后收集细胞。采用RT-PCR法检测LoVo细胞中FOXD1的表达情况,流式细胞术检测LoVo细胞凋亡情况,Western blot检测细胞中FOXD1蛋白的水平,细胞克隆测定细胞存活率,裸鼠成瘤实验取转染未经X射线照射的C组、M组、I组LoVo细胞细胞悬液,各取0.2 ml分别接种于C组、M组、I组BALB/C-nu雄性裸鼠左下肢足部皮上1次,每组10只,注射2周后,各组选取5只裸鼠进行X射线照射,每天4 Gy照射一次,连续照射15 d,其余小鼠不照射,处死裸鼠并取出肿瘤进行称重。结果:与C组比对,M组FOXD1水平明显升高,I组...     

X射线对A549细胞DNA的损伤可能与JAK/STAT信号通路的激活有关

本研究旨在观察不同剂量X射线对A549细胞DNA的损伤和JAK/STAT信号通路激活水平之间的关系。分别用2、4、8Gy X射线对A549细胞进行照射后,用CCK8法检测A549细胞增殖情况,用酶联免疫法检测照射后不同时间点培养液上清中白介素6 (interleukin 6, IL-6)的含量,用免疫荧光染色法检测细胞IL-6受体(IL-6 receptor, IL-6R)和p53结合蛋白1 (p53 binding protein 1, 53BP1)的蛋白表达情况,用Western blot检测细胞JAK2、p-JAK2、STAT3和p-STAT3的蛋白表达水平。结果显示,和对照组相比,X射线照射可降低细胞增殖水平,上调53BP1表达,提高细胞培养液上清中IL-6含量,并上调IL-6R、JAK2、p-JAK2、STAT3和p-STAT3表达水平。X射线照射的上述作用存在一定的剂量依赖性。以上结果提示,X射线造成细胞DNA损伤的机制可能与JAK/STAT信号通路的激活有关。     

Wnt/beta-catenin 信号通路活化的人滑膜细胞对软骨细胞的影响

目的：研究Wnt/beta-catenin 信号通路活化的人滑膜细胞对软骨细胞的作用,探讨骨关节炎（OA）发生及进展的可能途径和分子 机制。方法：beta-catenin 过表达慢病毒载体转染正常人滑膜细胞,荧光显微镜观察病毒转染情况,Western blot方法检测滑膜细胞核 内beta-catenin 蛋白表达。Transwell 小室共培养人滑膜细胞与正常人软骨细胞,倒置显微镜观察滑膜细胞对软骨细胞生长形态变化 的影响。酶联免疫吸附（ELISA）法检测不同时间点共培养体系中软骨细胞培养上清液中MMP-7 的变化,找出MMP-7 变化最明 显的时间点。同时在最佳时间点ELISA 方法检测软骨细胞培养上清液CTX-II、COMP的水平。结果：慢病毒转染滑膜细胞后,荧 光显微镜下可见多数滑膜细胞表达荧光,Western blot检测发现滑膜细胞胞浆及胞核中茁-catenin 表达明显上调（P<0.01）。通路活 化的人滑膜细胞与软骨细胞共培养后,光镜下观察软骨细胞生长形态变化不明显,但随共培养时间的延长软骨细胞生长受到抑 制,胞体边缘发白,贴壁强度降低。ELISA 结果显示通路活化的人滑膜细胞与软骨细胞共培养后软骨细胞上清液中MMP-7表达 明显升高,与正常组相比有显著差异（P<0.01）,软骨细胞上清液MMP-7 的变化有一定的时间依赖性,在共培养2 h、6 h、12 h时逐 渐升高,24 h 时略有降低,且在共培养6 h 时变化最为明显。而共培养6 h时通路激活组软骨细胞培养上清液中COMP、CTX-II水 平与正常对照组相比均明显升高（P<0.01）。结论：茁-catenin 过表达慢病毒转染正常人滑膜细胞可成功激活Wnt/茁-catenin 信号通 路,Wnt/茁-catenin 信号通路活化的滑膜细胞可影响正常软骨细胞的生长,并引起滑膜- 软骨体系内环境异常,促使软骨基质的降 解,这可能是滑膜炎促进OA 发生、发展的机制之一。     

人巨细胞病毒感染通过Wnt/β-catenin通路抑制滋养细胞的增殖及侵袭

人巨细胞病毒(Human cytomegalovirus,HCMV)感染能够影响胎盘绒毛外滋养细胞的增殖、侵袭,进而参与病理妊娠的发生,但具体的机制尚未阐明.在真皮成纤维细胞中的研究表明,HCMV能够抑制Wnt/β-catenin通路.因此,为了观察HCMV感染通过Wnt/β-catenin通路抑制滋养细胞增殖及侵袭的作用,本研究培养了人绒毛外滋养细胞株HTR8/SVneo.研究分为对照组、HCMV组、HCMV+LiCl组细胞.对照组细胞用培养液处理,HCMV组细胞用含有3个感染复数(Multiplicity of infection,MOI)HCMV的培养液处理,HCMV+LiCl组细胞用含有3MOI HCMV及50mmol/L Wnt/β-catenin通路激活剂LiCl的培养液处理.48小时后,采用MTS法检测细胞增殖,采用Transwell检测细胞侵袭,采用western blot检测细胞周期蛋白D1(cyclin D1)、基质金属蛋白酶2(Matrix metalloproteinase 2,MMP2)、基质金属蛋白酶9(Matrix metalloproteinase 9,MMP9)、β-连环蛋白(β-catenin)和磷酸型糖原合酶激酶-3β(p-GSK-3β)的表达量.结果显示,与对照组细胞相比,HCMV组细胞的O.D490水平、侵袭数目及cyyclinD1、MMP2、MMP9、β-catenin、p-GSK-3β的表达量均降低(P＜0.05);与HCMV组细胞比较,HCMV+LiCl组细胞的O.D490水平、侵袭数目及cyclinD1、MMP2、MMP9、β-catenin、p-GSK-3β的表达量均增加(P＜0.05).以上结果表明,HCMV感染抑制人绒毛外滋养细胞的增殖和侵袭,且该作用与抑制Wnt/β-catenin通路有关.本研究阐明了HCMV感染通过抑制Wnt/β-catenin信号通路的激活而抑制滋养细胞增殖及侵袭的分子机制,为最终阐明HCMV先天感染的致病机理积累了有价值的研究资料.     

Axin, a negative regulator of the Wnt signaling pathway, forms a complex with GSK-3beta and beta-catenin and promotes GSK-3beta-dependent phosphorylation of beta-catenin.

Glycogen synthase kinase-3 (GSK-3) mediates epidermal growth factor, insulin and Wnt signals to various downstream events such as glycogen metabolism, gene expression, proliferation and differentiation. We have isolated here a GSK-3beta-interacting protein from a rat brain cDNA library using a yeast two-hybrid method. This protein consists of 832 amino acids and possesses Regulators of G protein Signaling (RGS) and dishevelled (Dsh) homologous domains in its N- and C-terminal regions, respectively. The predicted amino acid sequence of this GSK-3beta-interacting protein shows 94% identity with mouse Axin, which recently has been identified as a negative regulator of the Wnt signaling pathway; therefore, we termed this protein rAxin (rat Axin). rAxin interacted directly with, and was phosphorylated by, GSK-3beta. rAxin also interacted directly with the armadillo repeats of beta-catenin. The binding site of rAxin for GSK-3beta was distinct from the beta-catenin-binding site, and these three proteins formed a ternary complex. Furthermore, rAxin promoted GSK-3beta-dependent phosphorylation of beta-catenin. These results suggest that rAxin negatively regulates the Wnt signaling pathway by interacting with GSK-3beta and beta-catenin and mediating the signal from GSK-3beta to beta-catenin.     

Wnt/beta-catenin 通路在成骨细胞中的作用

Wnt信号通路包括经典通路和非经典通路两种,其中Wnt经典通路又称为Wnt/β-catenin通路,其在成骨细胞的分化、增殖过程中发挥这重要的作用。Wnt信号通路实现过程中有多种因子参与,包括Wnt蛋白、β-catenin、蛋白激酶GSK-3β以及APC蛋白等多种。Wnt蛋白家族是由19种Wnt蛋白组成的,主要分为经典Wnt蛋白和非经典Wnt蛋白,其本质是一系列高度保守的分泌性糖蛋白,并且不同的Wnt蛋白对成骨细胞发挥着不同的作用,其中经典Wnt蛋白通过经典Wnt信号作用于成骨细胞对成骨细胞的增殖、分化有着重要的影响。本综述通过对Wnt经典信号通路过程中的多种因子与成骨细胞分化、增殖的关系进行分析总结,了解Wnt/β-catenin通路对成骨细胞的作用。     

The effect of pleiotrophin signaling on adipogenesis

Pleiotrophin (PTN) plays diverse roles in cell growth and differentiation. In this investigation, we demonstrate that PTN plays a negative role in adipogensis and that glycogen synthase kinase 3beta (GSK-3beta) and beta-catenin are involved in the regulation of PTN-mediated preadipocyte differentiation. Knocking down the expression of PTN using siRNA resulted in an increase in phospho-GSK-3beta expression, and the accumulation of nuclear beta-catenin, which are critical downstream signaling proteins for both the PTN and Wnt signaling pathways. Our investigation suggests that there is a PTN/PI3K/AKT/GSK-3beta/beta-catenin signaling pathway, which cross-talks with the Wnt/Fz/GSK-3beta/beta-catenin pathway and negatively regulates adipogenesis.     

Inhibition of the Wnt signaling pathway by the PR61 subunit of protein phosphatase 2A

Axin, a negative regulator of the Wnt signaling pathway, forms a complex with glycogen synthase kinase-3beta (GSK-3beta), beta-catenin, adenomatous polyposis coli (APC) gene product, and Dvl, and it regulates GSK-3beta-dependent phosphorylation in the complex and the stability of beta-catenin. Using yeast two-hybrid screening, we found that regulatory subunits of protein phosphatase 2A, PR61beta and -gamma, interact with Axin. PR61beta or -gamma formed a complex with Axin in intact cells, and their interaction was direct. The binding site of PR61beta on Axin was different from those of GSK-3beta, beta-catenin, APC, and Dvl. Although PR61beta did not affect the stability of beta-catenin, it inhibited Dvl- and beta-catenin-dependent T cell factor activation in mammalian cells. Moreover, it suppressed beta-catenin-induced axis formation and expression of siamois, a Wnt target gene, in Xenopus embryos, suggesting that PR61beta acts either at the level of beta-catenin or downstream of it. Taken together with the previous observations that PR61 interacts with APC and functions upstream of beta-catenin, these results demonstrate that PR61 regulates the Wnt signaling pathway at various steps.     

Expression and characterization of GSK-3 mutants and their effect on beta-catenin phosphorylation in intact cells

Glycogen synthase kinase-3 (GSK-3) is a serine-threonine kinase that is involved in multiple cellular signaling pathways, including the Wnt signaling cascade where it phosphorylates beta-catenin, thus targeting it for proteasome-mediated degradation. Unlike phosphorylation of glycogen synthase, phosphorylation of beta-catenin by GSK-3 does not require priming in vitro, i.e. it is not dependent on the presence of a phosphoserine, four residues C-terminal to the GSK-3 phosphorylation site. Recently, a means of dissecting GSK-3 activity toward primed and non-primed substrates has been made possible by identification of the R96A mutant of GSK-3beta. This mutant is unable to phosphorylate primed but can still phosphorylate unprimed substrates (Frame, S., Cohen, P., and Biondi R. M. (2001) Mol. Cell 7, 1321-1327). Here we have investigated whether phosphorylation of Ser(33), Ser(37), and Thr(41) in beta-catenin requires priming through prior phosphorylation at Ser(45) in intact cells. We have shown that the Arg(96) mutant does not induce beta-catenin degradation but instead stabilizes beta-catenin, indicating that it is unable to phosphorylate beta-catenin in intact cells. Furthermore, if Ser(45) in beta-catenin is mutated to Ala, beta-catenin is markedly stabilized, and phosphorylation of Ser(33), Ser(37), and Thr(41) in beta-catenin by wild type GSK-3beta is prevented in intact cells. In addition, we have shown that the L128A mutant, which is deficient in phosphorylating Axin in vitro, is still able to phosphorylate beta-catenin in intact cells although it has reduced activity. Mutation of Tyr(216) to Phe markedly reduces the ability of GSK-3beta to phosphorylate and down-regulate beta-catenin. In conclusion, we have found that the Arg(96) mutant has a dominant-negative effect on GSK-3beta-dependent phosphorylation of beta-catenin and that targeting of beta-catenin for degradation requires prior priming through phosphorylation of Ser(45).