携带绿色荧光蛋白的外源性胶质纤维酸性蛋白基因稳定转染对胶质瘤细胞分化及增殖的影响

目的观察增强胶质纤维酸性蛋白(glial fibrillary acidic protein,GFAP)基因表达对恶性胶质瘤细胞生物学特性的影响,为胶质瘤诱导分化及基因治疗研究提供理论基础。方法构建携带1．1kb的GFAP cDNA和绿色荧光蛋白(GFP)基因的真核表达载体,采用脂质体转染法将其导入人恶性胶质瘤细胞系SHG-44,G418结合荧光动态监测筛选阳性克隆;采用原位杂交、免疫细胞化学及Western蛋白印迹等方法检测GFAP基因及其蛋白表达;并通过形态学、细胞生长曲线、软琼脂克隆形成及流式细胞分析等观察GFAP基因对胶质瘤细胞形态、增殖和细胞周期的影响。结果转染阳性的SHG-44细胞GFAP mRNA及其蛋白表达增强,瘤细胞形态趋向成熟,突起增多变细,细胞增殖速度减缓,G0／G1期、G2／M期细胞比例降低。结论增强GFAP基因表达可显著抑制胶质瘤细胞增殖并诱导其分化成熟,提示通过基因治疗策略或诱导分化方法上调GFAP基因表达是恶性胶质瘤治疗的新途径。     

丙戊酸钠对人脑胶质瘤细胞系SHG-44增殖分化的影响

目的 研究丙戊酸钠对培养人脑胶质瘤细胞系SHG-44细胞的增殖抑制和分化诱导作用。方法 以0.25、0.5、1.0、2.0、4.0mmol/L丙戊酸钠处理SHG-44细胞,用MTT比色、流式细胞术、光镜观察、免疫组化染色等方法检测处理细胞。结果 SHG-44细胞经丙戊酸钠处理后：（1）细胞增殖受到明显抑制,并具有时间,剂量依赖性;（2）细胞周期受阻,S期细胞比例减少,G1期细胞比例增多;（3）胶质纤维酸性蛋白（glialfibrillaryacidicprotein,GFAP）表达增强。结论 丙戊酸钠能抑制人脑胶质瘤细胞系SHG-44细胞的增殖,1.0mmol/L丙戊酸钠能诱导SHG-44细胞发生明显分化。     

恶性胶质瘤细胞SHG-44诱导分化后的差异蛋白质组双向电泳分析

目的用双向电泳分析诺帝诱导胶质瘤细胞SHG-44分化后的差异蛋白质组,为进一步了解这些差异蛋白质的作用打下基础。方法将诺帝诱导胶质瘤细胞SHG-44分化后的总蛋白及其相应的空白对照组细胞总蛋白进行双向电泳分离,重复3次后用PDQuest7.1软件比较分析蛋白质表达差异并获得差异蛋白质的相对分子质量、等电点等信息。结果诺帝诱导胶质瘤细胞SHG-44分化后有23个差异蛋白点,其中21个蛋白点表达下调,2个蛋白点表达上调。结论诺帝诱导胶质瘤细胞SHG-44分化后大部分蛋白质表达下调,推测诺帝诱导胶质瘤细胞SHG-44分化时蛋白表达以抑制作用为主。     

MAGE-A1在人脑胶质瘤中的表达及其意义

为探讨黑色素瘤抗原A1(melanoma antigen A1,MAGE-A1)蛋白在人脑胶质瘤中的表达与其恶性程度的关系,用免疫组织化学SABC法检测48例人脑胶质瘤标本、2株人脑胶质瘤细胞系U87、SHG-44及6名正常人脑组织中MAGE-A1蛋白的表达.同时采用免疫荧光染色后流式细胞仪分析及荧光显微镜观察2株胶质瘤细胞MAGE-A1的表达.结果显示,MAGE-A1蛋白在I～Ⅳ级胶质瘤组织中阳性率分别为25.0%,29.4%,38.5%和50.0%,正常脑组织无表达.胶质瘤细胞系U87、SHG-44细胞MAGE-A1的表达率分别为77.3%,95.8%.表明MAGE-A1蛋白表达于人脑胶质瘤细胞,并与其恶性程度相关.     

脑胶质瘤细胞优势表达Th2类细胞因子的研究

细胞因子在调节肿瘤生长及肿瘤免疫之间起着重要的作用,它们可以促进或抑制肿瘤细胞的生长[1,2]。近年来,许多脑肿瘤研究者从培养人脑胶质瘤细胞株和胚胎脑胶质细胞入手观察到细胞因子的持续表达和分泌,推测脑胶质瘤的发生、发展可能与一些细胞因子基因的异常表达和分泌有关。我们采用RT-PCR法,对10株人脑胶质瘤细胞进行了IL-4、IL-6、IL-10和TNF-α的检测。1 材料和方法1.1 材料人脑胶质瘤细胞株SHG-44和SGBM-96由我科自建培养。SKI-1、T98G、MGR-2 UW28、MGR-3,SF295, UWR-7 和SF767,由加拿大麦吉尔大学PAN…     

人胶质瘤干细胞趋化因子受体CXCR4活化促进血管生成的作用

目的从人恶性胶质瘤细胞系U87中分离、培养和鉴定胶质瘤干细胞,观测其CXCR4表达情况及其活化后促血管生成因子分泌的变化。方法通过流式细胞术检测U87细胞中CD133阳性细胞的比例。使用CD133免疫磁珠分离试剂盒通过磁性细胞分选系统分离胶质瘤干细胞。采用间接免疫荧光标记、激光共聚焦扫描显微术观测胶质瘤干细胞中神经巢蛋白（nestin）、胶质纤维酸性蛋白（GFAP）、趋化因子受体CXCR4的表达;以CXCR4配体刺激通过钙流试验检测受体功能,采用酶联免疫吸附试验（EIJSA）检测培养上清中血管内皮生长因子（VEGF）和白细胞介素-8（IL-8）的含量。建立裸鼠皮下移植瘤模型,观察胶质瘤干细胞成瘤情况及瘤体内VEGF表达情况。结果U87细胞系中CD133阳性细胞的比例为0．5％,这些细胞具有干细胞增殖和生长特性;它们表达CXCR4,用其相应配体激活后导致胞内钙流增加、分泌VEGF和IL-8增多。与CD133阴性细胞相比,CD133阳性细胞在体外分泌VEGF、IL-8多,在体内成瘤率高,形成的移植瘤生长迅速,表达更多VEGF。结论人恶性胶质细胞瘤细胞系U87中含有极少量胶质瘤干细胞,表达功能性CXCR4、分泌更多促血管生成因子,提示这些干细胞也直接参与胶质瘤血管生成。     

人恶性胶质瘤细胞裸鼠脑原位移植瘤FPR表达与VEGF关系

目的观测甲酰肽受体(formylpeptide receptor,FPR)在人恶性胶质瘤细胞系U87细胞裸鼠脑原位移植瘤组织中的表达,以及与血管内皮生长因子(VEGF)的关系,探讨FPR在恶性胶质瘤血管生成过程中的作用。方法培养U87细胞,以立体定向注射技术制作U87裸鼠脑原位移植瘤模型;采用间接免疫荧光染色在激光共聚焦显微镜下分别观测FPR在U87细胞和移植瘤组织的表达;免疫组化方法检测VEGF在U87细胞裸鼠脑移植瘤上的表达。结果培养的U87细胞及其原位移植瘤组织均可见FPR表达,定位于瘤细胞胞膜,VEGF阳性着色主要位于胞质,两者阳性表达程度呈正相关性。结论人恶性胶质瘤细胞系U87细胞裸鼠脑原位移植瘤组织存在FPR表达,与VEGF的产生密切相关,在胶质瘤血管生成过程中可能起重要作用。     

西兰花多肽组分II诱导神经胶质瘤细胞凋亡的作用及其机制研究

 目的：探讨西兰花多肽组分II诱导胶质瘤细胞凋亡的作用及机制。方法：培养人神经胶质瘤SHG-44细胞,将其分为对照组以及3、10、30和100 mg/L西兰花多肽组分II组,MTT法检测西兰花多肽组分II作用后细胞活力的变化;Annexin V/PI 检测细胞的凋亡率;倒置显微镜观察西兰花多肽组分II诱导细胞凋亡的形态学变化;免疫细胞化学和Western blotting法检测西兰花多肽组分II作用后Bax、Bcl-2蛋白表达,Western blotting法检测caspase-3蛋白表达。结果：西兰花多肽组分II作用SHG-44细胞24 h 、48 h和72 h时均可以降低细胞活力,作用呈时间-剂量依赖性。Annexin V/PI 检测细胞凋亡率发现,各用药组细胞凋亡率随着药物剂量的增加而显著升高。倒置显微镜下观察,西兰花多肽组分II作用SHG-44细胞72 h后,各用药组细胞的密度随药物浓度升高而明显降低,并可见到明显的凋亡小体。细胞免疫组织化学和Western blotting结果显示,药物作用SHG-44细胞72 h后,与对照组比较,细胞Bax蛋白表达呈上升趋势,Bcl-2蛋白表达呈下降趋势,各用药组Bax/Bcl-2比值均明显增加（P<0.05或P<0.01）;Western blotting检测caspase-3蛋白发现,各药物组caspase-3蛋白表达量均增加,与空白对照组比较,30和100 mg/L西兰花多肽组分II组差异有统计学意义（P<0.01）。结论：西兰花多肽组分II可提高神经胶质瘤细胞中Bax/Bcl-2蛋白的比值,促进caspase-3蛋白活化,从而诱导肿瘤细胞凋亡。     

DNA拓扑异构酶-Ⅱα沉默对脑胶质瘤干细胞增殖和凋亡的影响

目的由U87MG细胞分离并鉴定脑胶质瘤干细胞,研究Topo-Ⅱα基因对脑胶质瘤干细胞增殖和凋亡的影响。方法培养脑胶质瘤U87MG细胞,分离和鉴定其中的胶质瘤干细胞。将Topo-Ⅱα基因特异性的siRNA转染胶质瘤干细胞。转染后,Western Blot检测转染后Topo-Ⅱα蛋白的表达,MTT法检测细胞增殖活力,双标流式法检测细胞凋亡率。结果成功分离出U87MG细胞球细胞,并鉴定其具有肿瘤干细胞特性。转染Topo-Ⅱα基因特异性的siRNA后,胶质瘤干细胞中的Topo-Ⅱα蛋白表达明显降低,同时,细胞增殖能力显著降低,凋亡率明显增加。结论由U87MG细胞系中分离出细胞球细胞具备肿瘤干细胞特性,Topo-Ⅱα基因沉默降低胶质瘤干细胞的增殖能力,促进细胞凋亡。     

细胞周期蛋白D1和细胞周期蛋白质依赖激酶4在去甲二氢愈创木酸抑制恶性胶质瘤细胞增殖中的作用

近年来发现去甲二氢愈创木酸(nordihydroguaiaretic acid, NDGA)能阻止多种肿瘤的发生和抑制其细胞的增殖[1-3],但机制不清.我们检测了NDGA对SHG-44细胞细胞周期蛋白D1(cyclin D1)基因的蛋白表达及细胞周期蛋白质依赖激酶4 (cyclin-dependent kinase 4,CDK4)活性的影响,旨在探讨NDGA抑制SHG-44细胞增殖的分子机制.     

Co-expression of low molecular weight neurofilament protein and glial fibrillary acidic protein in established human glioma cell lines.

This report describes the expression of glial and neuronal cytoskeletal proteins and their messenger RNAs (mRNAs) in established cell lines derived from human primitive neuroectodermal tumors (PNETs) and malignant gliomas. Northern blot analyses revealed neurofilament (NF) protein mRNAs in 6 of 7 PNET cell lines but no glial fibrillary acidic protein (GFAP) mRNA. Six of these cell lines contained mRNA for the microtubule-associated protein (MAP) known as MAP1b, whereas MAP2 mRNAs were detected only in 1 of the PNET cell lines. These findings closely paralleled previously published data on the expression of these cytoskeletal proteins in the same group of PNET cell lines. Although GFAP mRNA was detected in only 2 of 5 glioma cell lines, 4 of these cell lines contained mRNAs for the low-molecular-weight (M(r)) NF protein (NF-L). Western blot analysis confirmed the expression of both GFAP and NF-L protein in 2 of the glioma cell lines (U251 MG and U373 MG) that contained GFAP and NF-L mRNAs. Further, double immunofluorescence studies showed that GFAP and NF-L co-localized in the same glioma cells. In contrast, neither the middle- (NF-M) or high- (NF-H) M(r) NF proteins or their mRNAs were detected in any of these glioma cell lines. Finally, MAP1b mRNA was expressed in all 5 glioma cell lines, whereas MAP2 mRNAs were detected in only 3 of the cell lines. This is the first documentation of the expression of both glial-specific and neuron-specific cytoskeletal proteins in human malignant glioma-derived cell lines. These data may reflect the aberrant induction of neuron-specific gene products in some neoplastic glial cell lines. Alternatively, our findings may indicate that some glioma cell lines correspond to transformed bipotential human central nervous system precursors of cells restricted to a neuronal or glial lineage.     

改良的体外中枢神经系统损伤后胶质瘢痕模型的建立

目的建立胶质疤痕体外模型,观察其形态及细胞外基质的表达情况。方法体外分别培养来自大脑皮层的星形胶质细胞和脑膜成纤维细胞,经胶质纤维酸性蛋白(GFAP)和纤连蛋白(FN)抗体免疫细胞化学染色鉴定后,将两种细胞混合共培养,2d后添加转化生长因子-β1(TGF-β1),以未添加TGF-β1为对照组;GFAP和FN免疫细胞化学染色观察胶质疤痕的形态;免疫细胞化学染色和Western blotting观察促红素肝细胞受体B2(Eph B2)、Eph受体作用配体B2(ephrin B2)、神经蛋白聚糖(neurocan)和神经抗原2(NG2)表达情况。结果疤痕样细胞团簇结构主要是由星形胶质细胞和成纤维细胞共同组成;实验组Eph B2、ephrin B2和neurocan、NG2表达量较对照组明显增加(P0.05)。结论体外混合培养星形胶质细胞与成纤维细胞并添加TGF-β1后成功建立体外中枢神经系统损伤后疤痕模型。     

Down-regulation of endothelial ephrinB2 expression by laminar shear stress.

The EphB receptors and their ephrinB ligands are involved in vascular assembly and differentiation. In this study, the authors analyzed the regulation of ephrinB2 and EphB4 in response to laminar shear stress in human endothelial cells. In order to simulate different flow conditions in vitro, human endothelial cells were exposed to laminar shear stress (1 to 50 dyn/cm2 for up to 24 h) in a cone-and-plate viscometer. EphrinB2 mRNA expression is down-regulated by arterial, but not by venous, laminar shear stress in a dose-dependent manner in primary cultures of human umbilical vein endothelial cells (HUVECs) (maximum at 30 dyn/cm2, 24 h: 46% +/- 4%of internal control without shear stress, n = 16, p < .05). The down-regulation of ephrinB2 by arterial shear stress is blocked by the protein kinase C inhibitor RO-31-8220. A similar shear stress-dependent down-regulation of ephrin-B2 can be found in human coronary artery endothelial cells (HCAECs). Chronic application of laminar shear stress does not affect EphB4 expression in venous and arterial endothelial cells. The down-regulation of ephrinB2 in response to laminar shear stress may contribute to the differentiation of endothelial cells into a nonactivated phenotype.     

Products of cells cultured from gliomas. VII. Extracellular matrix proteins of gliomas which contain glial fibrillary acidic protein

Extracellular matrix (ECM) components of two glial fibrillary acidic protein positive (GFAP+) glioma lines U251 and UM6 were studied by silver stain, morphometry, immunofluorescence, enzyme-linked immunosorbent assay, and biosynthetic labeling. Both GFAP+ lines expressed the following qualitative features in common with previously studied GFAP-negative gliomas: (a) laminin, (b) type IV collagen, (c) extracellular fibrils of silver-reducing collagen (d) pattern of reactivity with lectins. Quantitative differences in GFAP+ glioma proteins included less collagen and more laminin than GFAP-negative gliomas. Sparse collagen of GFAP+ gliomas aggregated as extracellular masses. Individual cells of UM6 simultaneously expressed GFAP and mesenchymal ECM components. Results show qualitative similarities of ECM expression among GFAP+ and negative gliomas suggesting a common lineage of these two glioma cell types and universal expression of two epithelial components of ECM, laminin and type IV collagen, among cultured gliomas. Moreover, there is a diversity of quantity and type of ECM proteins of GFAP+ gliomas with the U251 line most restricted in its expression of ECM components and with UM6 manifesting markers of epithelial and mesenchymal lineage. This diversity suggests a capacity for regulation of phenotypic expression of ECM beyond that explained simply by the presence of two cell types of different lineage.     

恶性胶质瘤细胞株的蛋白质组差异表达分析

目的 寻找和鉴定恶性胶质瘤细胞株的蛋白质组差异蛋白表达谱,为以其为基础的相关研究提供必要参考.方法 提取3个恶性胶质瘤细胞株CHG-5、TJ899和TJ905的总蛋白,等比例混匀后行双向电泳,正常胶质细胞为平行对照,筛选和鉴定差异蛋白质点,并就其中部分蛋白质进行免疫细胞化学和实体瘤免疫组织化学验证.结果 共筛选出13个差异蛋白质点,其中10个得到成功鉴定,它们主要分属于细胞骨架蛋白、代谢相关蛋白、肿瘤细胞迁移,以及应激与炎性反应相关蛋白;免疫细胞化学和实体瘤免疫组织化学检测结果与蛋白质组技术结果相一致.结论 恶性胶质瘤细胞株与正常胶质细胞比较具有明显的多个差异蛋白表达,它们可能共同参与脑胶质细胞的瘤变过程.     

Roles of ephrinB ligands and EphB receptors in cardiovascular development: demarcation of arterial/venous domains, vascular morphogenesis, and sprouting angiogenesis

Eph receptor tyrosine kinases and their cell-surface-bound ligands, the ephrins, regulate axon guidance and bundling in the developing brain, control cell migration and adhesion, and help patterning the embryo. Here we report that two ephrinB ligands and three EphB receptors are expressed in and regulate the formation of the vascular network. Mice lacking ephrinB2 and a proportion of double mutants deficient in EphB2 and EphB3 receptor signaling die in utero before embryonic day 11.5 (E11.5) because of defects in the remodeling of the embryonic vascular system. Our phenotypic analysis suggests complex interactions and multiple functions of Eph receptors and ephrins in the embryonic vasculature. Interaction between ephrinB2 on arteries and its EphB receptors on veins suggests a role in defining boundaries between arterial and venous domains. Expression of ephrinB1 by arterial and venous endothelial cells and EphB3 by veins and some arteries indicates that endothelial cell-to-cell interactions between ephrins and Eph receptors are not restricted to the border between arteries and veins. Furthermore, expression of ephrinB2 and EphB2 in mesenchyme adjacent to vessels and vascular defects in ephB2/ephB3 double mutants indicate a requirement for ephrin–Eph signaling between endothelial cells and surrounding mesenchymal cells. Finally, ephrinB ligands induce capillary sprouting in vitro with a similar efficiency as angiopoietin-1 (Ang1) and vascular endothelial growth factor (VEGF), demonstrating a stimulatory role of ephrins in the remodeling of the developing vascular system.     

EphB4 Tyrosine Kinase Stimulation Inhibits Growth of MDA-MB-231 Breast Cancer Cells in a Dose and Time Dependent Manner

Background. EphB4 receptor tyrosine kinase is of diagnostic and therapeutic value due to its overexpression in breast tumors. Dual functions of tumor promotion and suppression have been reported for this receptor based on presence or absence of its ligand. To elucidate such discrepancy, we aimed to determine the effect of time- and dose-dependent stimulation of EphB4 on viability and invasion of breast cancer cells via recombinant ephrinB2-Fc. Methods. Cells were seeded into multiwell plates and were stimulated by various concentrations of preclustered ephrinB2-Fc. Cell viability was measured on days 3 and 6 following treatment using alamar-blue when cells were in different states of confluence. Results. Stimulation of cells with ephrinB2 did not pose any significant effect on cell viability before reaching confluence, while inhibition of cell growth was detected after 6 days when cells were in postconfluent state following a dose-dependent manner. EphrinB2 treatment did not affect tubular formation and invasion on matrigel. Conclusion. This study showed that EphB4 can differentially inhibit cells at post confluent state and that presence of ligand manifests growth-inhibitory properties of EphB4 receptor. It is concluded that growth inhibition has occurred possibly due to long treatment with ligand, a process which leads to receptor downregulation.     

Altered vascular expression of EphrinB2 and EphB4 in a model of oxygen‐induced retinopathy

EphrinB2 ligands and EphB4 receptors are expressed on endothelial cells (EC) of arteries and veins, respectively, and are essential for vascular development. To understand how these molecules regulate retinal neovascularization (NV), we evaluated their expression in a model of oxygen‐induced retinopathy (OIR). EphrinB2 and EphB4 were expressed on arterial and venous trunks, respectively, and on a subset of deep capillary vessels. EphB4 expression was reduced following hyperoxia, while ephrinB2 expression remained unaltered. In addition, a subset of EphB4‐positive veins regressed in a caspase‐3‐dependent manner during hyperoxia. Arteriovenous malformations were also observed with loss of arterial‐venous boundaries. Finally, both ephrinB2 and EphB4 were expressed on a subset of neovascular tufts following hyperoxia. These data confirm the contribution of ECs from both venous and arterial origins to the development of retinal NV. Developmental Dynamics 239:1695–1707, 2010. © 2010 Wiley‐Liss, Inc.