WIF-1启动子甲基化与肿瘤关系的研究进展

WIF-1(Wnt inhibitory factor-1)是Wnt拮抗物家族之一,能够阻断Wnt蛋白信号通路,抑制肿瘤的生长分化。在大多数肿瘤中,WIF-1基因启动子甲基化导致抑癌基因WIF-1低表达,从而失去其阻断Wnt/β-catenin信号通路异常激活的作用。而甲基化的WIF-1经去甲基化剂作用后可恢复抑癌基因WIF-1表达,抑制肿瘤的发生。本文就目前国内外针对WIF-1与结直肠癌、肺癌和泌尿系肿瘤关系的研究进展作一综述,为完善疾病治疗提供更加妥善的方法。     

下调TPD52基因表达通过Wnt信号通路对子宫肌瘤细胞活力、凋亡及TNF-α和IL-6表达的影响

目的:探讨下调肿瘤蛋白D52(TPD52)基因表达通过Wnt信号通路对子宫肌瘤细胞活力、凋亡及肿瘤坏死因子α(TNF-α)和白细胞介素6(IL-6)表达的影响。方法:将针对TPD52的特异性si RNA(si-TPD52)及其阴性对照转染原代培养的子宫肌瘤细胞,并加入Dickkopf-1(DKK1)作为Wnt信号通路抑制剂,转染48 h后,用Western blot检测TPD52及Wnt信号通路关键分子β-catenin和相关靶蛋白cyclin D1和survivin的蛋白表达; MTT及流式细胞术分别检测细胞活力和凋亡率的变化; RT-qPCR检测TNF-α和IL-6的m RNA表达。结果:TPD52在转染si-TPD52的子宫肌瘤细胞的表达显著低于空白对照组和阴性对照组(P 0. 05);与阴性对照组比较,si-TPD52组细胞活力明显受到抑制,凋亡率增加,TNF-α的m RNA表达降低,IL-6的m RNA表达升高,β-catenin、cyclin D1和survivin的蛋白表达降低(P 0. 05);加入DKK1后si-TPD52对细胞活力和凋亡的影响更明显。结论:下调TPD52基因表达可通过Wnt信号通路抑制子宫肌瘤细胞生长和诱导凋亡,同时下调TNF-α和上调IL-6表达。     

丙戊酸钠通过上调Wnt/β-catenin信号通路促进培养神经元的生长(英文)

目的:丙戊酸盐(丙戊酸valproic acid,VPA)在过去数十年应用于临床治疗癫痫和偏头痛。然而,母亲怀孕早期使用VPA将大大增加子代罹患孤独症群谱障碍的易感性。鉴于Wnt/β-catenin信号通路对神经元增殖、分化、突起生长及凋亡的重要作用,本文旨在研究VPA在原代培养神经元中对Wnt/β-catenin信号通路的影响。方法:用VPA处理原代培养神经元,以生理盐水处理为对照,运用Western Blot检测Wnt/β-catenin通路相关信号分子Wnt1,Wnt2,WIF-1,Dickkopf 1及效应分子β-catenin的表达变化,同时运用免疫荧光技术观察神经元形态变化。结果:与对照组比较,VPA处理显著增加Wnt1及Wnt2的表达(P<0.05~0.01),而未增加WIF-1及Dickkopf 1的表达(P>0.05);VPA处理也导致Wnt/β-catenin通路活性上调,表现为神经元内β-catenin含量显著上升。此外,与对照组比较,VPA处理促进神经元生长,表现为神经元突起数目(P<0.05~0.01)及总长度显著增加(P<0.05~0.01);Wnt/β-catenin通路抑制剂能部分抑制VPA引起的Wnt/β-catenin通路活性上调及神经元生长。结论:VPA通过上调Wnt/β-catenin信号通路促进神经元生长,可能是VPA增加子代罹患孤独症群谱障碍易感性的原因。     

椎间盘退变中的Wnt信号通路

背景：Wnt信号通路在退变的椎间盘中过表达，而抑制其表达可延缓椎间盘退变进程，因此Wnt信号通路与椎间盘退变关系密切。目的：综述分析Wnt信号通路与椎间盘之间的相互关系，阐明Wnt信号通路在椎间盘退变进程中具体起到的作用和影响。方法：第一作者以“Intervertebral disc,Wnt,Cell proliferation,Cell senescence,Cell apoptosis,Extracellular matrix”为英文检索词，检索2000年至2023年1月PubMed数据库、Web of Science和OVID LWWspringlink数据库，查阅Wnt信号通路与椎间盘退变的相关研究文献，通过阅读整理保留54篇英文文献进行综述。结果与结论：(1)在胚胎的椎间盘形成过程中，Wnt信号通路可过表达，参与椎间盘形成并促进脊索后伸展。(2)在椎间盘退变过程中，Wnt信号通路可停滞细胞周期而抑制细胞增殖，使衰老相关蛋白表达增加并参与氧化应激而促进细胞衰老，此外还可受长链非编码RNA调控参与细胞凋亡。(3)Wnt信号通路亦可以减少细胞外基质相关蛋白合成、促进细胞外基质降解而...     

Notch和Wnt信号通路对神经干细胞增殖分化的影响

Notch和Wnt信号通路是调节神经干细胞(neural stem cells,NSCs)增殖、分化的重要通路,Notch信号通路的靶基因Hes1、Hes5及HES相关蛋白等分化抑制信号,通过旁侧抑制机制阻止NSCs的分化,并促进其自我更新;通过NICD与CSL DNA结合蛋白的直接结合,形成GFAP的转录激活复合物,上调GFAP的表达,从而促进NSCs向星形胶质细胞的分化。Wnt信号通过Wnt/β-catenin信号通路对细胞周期素D1和D2的转录调节,调控NSCs细胞周期的进程,使其量增殖;然而,过表达的Wnt3a和Wnt7a蛋白能够抑制NSCs的增殖,促进NSCs向神经元方向分化。     

Wnt2信号通路重要成员在胶质瘤中的表达及其意义

近来发现Wnt信号通路对个体发育和肿瘤生成具有重要作用[1-2].为进一步探讨Wnt通路在胶质瘤中是否存在表达异常及其在胶质瘤生成中的作用,我们采用RT-PcR、组织芯片免疫组织化学染色以及蛋白印迹法,对人脑胶质瘤Wnt2通路相关因子的表达变化及其意义进行了分析.     

Wnt2信号通路重要成员在胶质瘤中的表达及其意义

近来发现Wnt信号通路对个体发育和肿瘤生成具有重要作用[1-2].为进一步探讨Wnt通路在胶质瘤中是否存在表达异常及其在胶质瘤生成中的作用,我们采用RT-PcR、组织芯片免疫组织化学染色以及蛋白印迹法,对人脑胶质瘤Wnt2通路相关因子的表达变化及其意义进行了分析.     

Wnt2信号通路重要成员在胶质瘤中的表达及其意义

近来发现Wnt信号通路对个体发育和肿瘤生成具有重要作用[1-2].为进一步探讨Wnt通路在胶质瘤中是否存在表达异常及其在胶质瘤生成中的作用,我们采用RT-PcR、组织芯片免疫组织化学染色以及蛋白印迹法,对人脑胶质瘤Wnt2通路相关因子的表达变化及其意义进行了分析.     

Wnt2信号通路重要成员在胶质瘤中的表达及其意义

近来发现Wnt信号通路对个体发育和肿瘤生成具有重要作用[1-2].为进一步探讨Wnt通路在胶质瘤中是否存在表达异常及其在胶质瘤生成中的作用,我们采用RT-PcR、组织芯片免疫组织化学染色以及蛋白印迹法,对人脑胶质瘤Wnt2通路相关因子的表达变化及其意义进行了分析.     

Wnt2信号通路重要成员在胶质瘤中的表达及其意义

近来发现Wnt信号通路对个体发育和肿瘤生成具有重要作用[1-2].为进一步探讨Wnt通路在胶质瘤中是否存在表达异常及其在胶质瘤生成中的作用,我们采用RT-PcR、组织芯片免疫组织化学染色以及蛋白印迹法,对人脑胶质瘤Wnt2通路相关因子的表达变化及其意义进行了分析.     

转入WIF-1或5-氮杂-2’-脱氧胞苷去甲基化抑制骨肉瘤模型鼠的肿瘤生长

BACKGROUND:WIF-1 is a tumor suppressor gene. Promoter hypermethylation causes WIF-1 down- regulation in most tumors. DNA methylation inhibitor can lead to gene demethylation and restore its expression. OBJECTIVE:To observe the differences of tumor pathology and, WIF-1 mRNA and protein changes using WIF-1 or 5-aza-2'-deoxycytidine demethylation in animal models of osteosarcoma. METHODS:Murine osteosarcoma models were established and divided into three groups. In the control group, no treatment was given. In the 5-aza-2'-deoxycytidine group, an appropriate amount of 5-aza-2'-deoxycytidine was injected in each mouse daily. In the WIF-1 group, an appropriate amount of Wnt/β-catenin signal transduction pathway inhibitor WIF-1 was injected in each mouse daily. Seven days after medication, the weight of nude mouse was weighed every 7 days. Short tumor diameter (a) and the long diameter (b) were measured. The relative tumor volume was calculated. The relative growth rate of tumor was calculated at 7, 14, 21, 28 and 56 days. Four nude mice from ach group were sacrificed by pulling the neck at 7, 14, 21, 28 and 56 days after medication. Tumor tissues were stripped and the weight of them was weighed. Pathological analysis of the tumor was conducted. The expression of WIF-1 protein and WIF-1 mRNA was detected in osteosarcoma at 56 days after medication in the three groups. RESULTS AND CONCLUSION: (1) Compared with the medication and control groups, the weight of nude mice was increased at 7, 14, 21, 28 and 56 days in the treatment group. No significant difference was found between the medication and control groups. (2) The tumor size was significantly smaller in the medication group than in the control group. WIF-1 mRNA and WIF-1 protein expression was increased in the medication group compared with the control group to different degrees. (3) Results suggested that WIF-1 gene promoter methylation is one of the mechanisms of the development of osteosarcoma. Use of WIF-1 or 5-aza-2'-deoxycytidine demethylation can inhibit tumor growth in animal models of osteosarcoma.     

Wnt信号转导途径与髓母细胞瘤

髓母细胞瘤是多发于儿童小脑的恶性肿瘤,其预后很差。Wnt信号转导途径对多种生物发育、细胞的增殖和分化起着重要的作用,如异常表达或激活该途径会导致各种疾病甚至肿瘤发生。在经典Wnt途径中β-连环蛋白是其关键成员。Wnt蛋白与跨膜受体Fz蛋白结合后，破坏多蛋白降解复合物，积累的β-连环蛋白进入胞核与转录因子Tcf/Lef形成复合体，从而激活下游靶基因。目前研究表明Wnt信号转导途径与髓母细胞瘤的致癌作用密切相关。     

Rhombomere boundaries are Wnt signaling centers that regulate metameric patterning in the zebrafish hindbrain.

The vertebrate hindbrain develops from a series of segments (rhombomeres) distributed along the anteroposterior axis. We are studying the roles of Wnt and Delta-Notch signaling in maintaining rhombomere boundaries as organizing centers in the zebrafish hindbrain. Several wnt genes (wnt1, wnt3a, wnt8b, and wnt10b) show elevated expression at rhombomere boundaries, whereas several delta genes (dlA, dlB, and dlD) are expressed in transverse stripes flanking rhombomere boundaries. Partial disruption of Wnt signaling by knockdown of multiple wnt genes, or the Wnt mediator tcf3b, ablates boundaries and associated cell types. Expression of dlA is chaotic, and cell types associated with rhombomere centers are disorganized. Similar patterning defects are observed in segmentation mutants spiel-ohne-grenzen (spg) and valentino (val), which fail to form rhombomere boundaries due to faulty interactions between adjacent rhombomeres. Stripes of wnt expression are variably disrupted, with corresponding disturbances in metameric patterning. Mutations in dlA or mind bomb (mib) disrupt Delta-Notch signaling and cause a wide range of patterning defects in the hindbrain. Stripes of wnt1 are initially normal but subsequently dissipate, and metameric patterning becomes increasingly disorganized. Driving wnt1 expression using a heat-shock construct partially rescues metameric patterning in mib mutants. Thus, rhombomere boundaries act as Wnt signaling centers required for precise metameric patterning, and Delta signals from flanking cells provide feedback to maintain wnt expression at boundaries. Similar feedback mechanisms operate in the Drosophila wing disc and vertebrate limb bud, suggesting coaptation of a conserved signaling module that spatially organizes cells in complex organ systems.     

Inhibition of Wnt activity induces heart formation from posterior mesoderm

In the chick, heart mesoderm is induced by signals from the anterior endoderm. Although BMP-2 is expressed in the anterior endoderm, BMP activity is necessary but not sufficient for heart formation. Previous work from our lab has suggested that one or more additional factors from anterior endoderm are required. Crescent is a Frizzled-related protein that inhibits Wnt-8c and is expressed in anterior endoderm during gastrulation. At the same stages, expression of Wnt-3a and Wnt-8c is restricted to the primitive streak and posterior lateral plate, and is absent from the anterior region where crescent is expressed. Posterior lateral plate mesoderm normally forms blood, but coculture of this tissue with anterior endoderm or infection with RCAS-crescent induces formation of beating heart muscle and represses formation of blood. Dkk-1, a Wnt inhibitor of a different protein family, similarly induces heart-specific gene expression in posterior lateral plate mesoderm. Furthermore, we have found that ectopic Wnt signals can repress heart formation from anterior mesoderm in vitro and in vivo and that forced expression of either Wnt-3a or Wnt-8c can promote development of primitive erythrocytes from the precardiac region. We conclude that inhibition of Wnt signaling promotes heart formation in the anterior lateral mesoderm, whereas active Wnt signaling in the posterior lateral mesoderm promotes blood development. We propose a model in which two orthogonal gradients, one of Wnt activity along the anterior-posterior axis and the other of BMP signals along the dorsal-ventral axis, intersect in the heart-forming region to induce cardiogenesis in a region of high BMP and low Wnt activity.     

Wnt Signaling as a Possible Promoting Factor of Cell Differentiation in Pleomorphic Adenomas

There are well known that Wnt signaling was some roles of cell differentiation at the development tissues, especially the oral and maxillofacial regions of some developmental stages. Therefore, to determine Wnt signaling in the pleomorphic adenoma tissues, we examined. The expression of Wnt1 and β-catenin as well as the distribution of various cytoskeletal proteins CK7 and CK13 was examined in 30 cases of pleomorphic adenoma by immunohistochemistry. Wnt1 was detected in almost all tumor cells. The peripheral columnar cells in squamous metaplasia and small cuboidal cells in duct-like structures were strongly positive to Wnt1. Although β-catenin was clearly localized on the cell membrane of tumor cells, nuclear translocation was observed in small cuboidal cells and in some basaloid cells. The immunofluorescent staining pattern of Wnt1 and CK7 as well as Wnt1 and CK13 was consistent with IHC results. Thus, in pleomorphic adenoma, Wnt is involved in tumor cell differentiation of peripheral columnar cells forming solid nests and small peripheral columnar cells forming duct-like structures. Moreover, among the three currently known Wnt pathways, β-catenin is the suggested pathway working during cell differentiation. Furthermore, peripheral columnar cells in solid tumor nests and in squamous metaplasia are governed by another Wnt pathway other than β-catenin. Therefore, Wnt signaling through β-catenin pathway may be involved in the ''mixed'' differentiation characteristic of pleomorphic adenoma although another pathway may also be possibly working in other parts of the tumor tissue.