人脑胶质瘤高表达nNav1.5促进肿瘤细胞侵袭

目的：观察电压-门控钠离子通道（VGSCs）亚型nNav1.5在人脑胶质瘤组织中的表达,探讨nNav1.5表达对胶质瘤U251细胞迁移及侵袭的影响。方法：收集本科室手术切除的脑胶质瘤标本68例,应用免疫组织化学S-P法检测胶质瘤组织中nNav1.5的表达。设计合成nNav1.5特异性小干扰RNA（small interfering RNA,siRNA）,用脂质体转染至U251细胞,应用Real-time RT-PCR和Western blot法分别检测nNav1.5的mRNA和蛋白表达水平的变化,应用划痕实验和Matrigel侵袭实验检测U251细胞迁移和侵袭能力。结果：与正常组织相比,nNav1.5在胶质瘤组织中表达率明显升高（72.6% vs 23.0%,P < 0.01）,并且其在低级别胶质瘤中（WHOⅠ～Ⅱ级）明显高于其在高级别胶质瘤（WHO Ⅲ～Ⅳ级）中的表达率（52.9% vs 85.8%,P < 0.01）;siRNA显著抑制U251细胞中nNav1.5的mRNA和蛋白表达并明显降低U251细胞的迁移侵袭能力。结论：电压-门控钠离子通道nNav1.5在胶质瘤中高表达并促进U251细胞的迁移和侵袭能力,nNav1.5是胶质瘤恶性侵袭的调控因子,有望成为胶质瘤的新标记物和治疗靶点。     

人脑胶质瘤组织高表达nNav1.5促进肿瘤细胞的迁移和侵袭

目的：观察电压-门控钠离子通道（voltage-gated sodium channel, VGSC）亚型nNav1.5在人脑胶质瘤组织中的表达,并探讨其对脑胶质瘤U251细胞迁移及侵袭的影响。方法：收集中国医科大学附属第一医院神经外科于2011年10月至2012年10月手术切除并经病理证实的脑胶质瘤组织标本68例,应用免疫组织化学S-P法检测脑胶质瘤组织中nNav1.5的表达。设计并化学合成nNav1.5基因特异性小干扰RNA（nNav1.5-siRNA）,用脂质体介导转染胶质瘤U251细胞,应用Real-time PCR和Western blotting法分别检测U251细胞中nNav1.5 mRNA和蛋白的表达水平,并采用细胞划痕实验和Transwell侵袭实验检测U251细胞迁移和侵袭能力的变化。结果：nNav1.5在人脑胶质瘤组织中表达的阳性率显著高于正常组织（72.6% vs 23.0%,P<0.01）,并且其在高级别胶质瘤（WHO Ⅲ～Ⅳ级）组织中的阳性率明显高于低级别胶质瘤（WHOⅠ～Ⅱ级）组织（85.8% vs 52.9%,P<0.01）。nNav1.5-siRNA转染可显著抑制U251细胞中nNav1.5 mRNA和蛋白的表达（P<0.01）;转染后U251细胞的迁移距离明显小于未转染细胞\[(0.019±0.015) vs（0.223±0.031）mm,P<0.01\],且其侵袭指数明显低于未转染细胞\[(2.99±0.15)% vs（6.77±0.26）%,P<0.01\]。〖JP2〗结论：nNav1.5在人脑胶质瘤组织中高表达,干扰nNav1.5表达可显著抑制胶质瘤细胞的迁移和侵袭能力,nNav1.5是胶质瘤恶性侵袭的调控因子并有望成为胶质瘤的新标志物和治疗靶点。     

上皮性肿瘤细胞中Snail与E-cadherin的表达及其与体外侵袭性的关系

目的 研究上皮性肿瘤细胞Snail与E-cadherin的表达以及与瘤细胞表型、转移潜能的关系。方法 采用Northern blot、共聚焦激光显微镜研究6株不同组织来源、不同分化程度及转移潜能的上皮性肿瘤细胞、1株正常上皮细胞、1株成纤维细胞中Snail与E-cadherin mRNA和蛋白表达与定位;Boyden小室体外侵袭实验反映细胞的转移潜能。结果 在分化程度较高的癌细胞和对照正常上皮细胞中,E-cadherin mRNA与蛋白表达较强,而Snail表达缺如;在分化程度低、转移潜能高的癌细胞和对照成纤维细胞中,E-cadherin、Snail mRNA及蛋白表达与上述情况相反。E-cadherin多定位于细胞胞浆和胞膜,Snail主要定位于胞核和胞浆。结论 在上皮性肿瘤细胞中E-cadherin和Snail在mRNA与蛋白表达水平上存在逆反关系,且与细胞分化、转移潜能相关。     

血管内皮生长因子在人脑胶质瘤侵袭中的作用

 目的　研究血管内皮生长因子 (Vascularendothelialgrowthfactor ,VEGF)在脑胶质细胞瘤中的表达情况 ,探讨其表达与肿瘤的恶性程度、肿瘤侵袭及预后的关系。方法　采用免疫组织化学染色检测 5 2例脑胶质瘤标本 ,4例垂体腺瘤 ,5例正常脑组织的VEGF表达水平。结果　在正常脑组织中未见VEGF免疫组化染色阳性细胞 ,垂体腺瘤偶有表达 ,脑胶质瘤组织中均有VEGF表达 (P <0 .0 5 )。随着脑胶质瘤恶性程度的增加 ,VEGF的表达增高 (P <0 .0 1)。生存期 <3年者VEGF的表达显著高于生存期 >3年者 (P <0 .0 1)。结论　VEGF的表达与胶质瘤的恶性程度和侵袭性等有关 ,并对其预后有一定的意义     

RNA干扰沉默MSI1表达对人脑胶质瘤细胞化疗敏感度的影响

目的 探讨RNA干扰沉默MSI1表达对人脑胶质瘤细胞化疗药物敏感度的影响。方法 构建针对MSI1 mRNA的小分子RNA干扰（siRNA）重组质粒pSIREN-MSI1,转染人脑胶质瘤U-87MG细胞;Western blot检测U-87MG细胞内MSI1蛋白的表达;CCK-8法观察U-87MG细胞对化疗药物替莫唑胺（TMZ）敏感度的改变;流式细胞仪（FCM）检测pSIREN-MSI1转染后对U-87MG细胞凋亡的影响。结果 成功构建了重组质粒pSIREN-MSI1,并成功转染U-87MG细胞;Western blot结果显示pSIREN-MSI1抑制U-87MG细胞中MSI1蛋白的表达（P<0.01）;CCK-8结果显示在替莫唑胺作用下,pSIREN-MSI1组U-87MG细胞的存活率明显下降（P<0.01）;FCM结果表明pSIREN-MSI1转染后明显提高U-87MG细胞的凋亡率（P<0.01）。结论 MSI1 siRNA能特异性抑制人脑胶质瘤细胞U-87MG细胞中MSI1的表达,增强人脑胶质瘤U-87MG细胞对化疗药物的敏感度,并促进细胞的凋亡。     

Leptin促进人脑胶质瘤U87MG细胞的迁移和侵袭

目的:探讨瘦素(leptin)对人脑胶质瘤U87MG细胞迁移及侵袭能力的影响及其机制。方法:Leptin处理U87MG细胞,采用细胞划痕实验检测U87MG细胞的迁移能力,Transwell实验检测U87MG细胞的侵袭能力,RT-PCR及Western blot-ting法检测U87MG细胞中MMP-2及MMP-9 mRNA和蛋白的表达。结果:Leptin明显促进U87MG细胞迁移能力[(152.42±3.29)vs(83.24±2.61)μm,P<0.05]和侵袭能力[(31.78±5.04)vs(17.03±2.41)个细胞,P<0.05],leptin能显著上调U87MG细胞中MMP-2、MMP-9 mRNA[(0.76±0.04)vs(0.35±0.02),(0.84±0.02)vs(0.41±0.06);均P<0.05]及蛋白[(0.79±0.03)vs(0.23±0.01),(0.81±0.05)vs(0.39±0.03);均P<0.05]的表达。MMP抑制剂GM6001(10μmol/ml)可以逆转leptin对U87MG细胞迁移[(82.05±2.98)vs(81.76±3.25)μm,P>0.05]和侵袭能力[(19.23±2.46)vs(18.02±1.98)个细胞,P>0.05]的影响。结论:Leptin可以促进人脑胶质瘤U87MG细胞的侵袭及迁移,其机制可能与上调MMP-2、MMP-9的表达有关。     

胶质瘤侵袭性的分子生物学机制

胶质瘤是脑部最常见的肿瘤，目前治疗效果不佳。而肿瘤的侵袭性是其难以治愈的重要原因之一。本文通过对蛋白溶解酶、细胞表面粘附分子、生长因子及局部粘着斑激酶等细胞蛋白分子在肿瘤中的作用机理作一阐述，以了解与胶质瘤侵袭性相关的分子生物学机制。     

微RNAlet-7d抑制胶质瘤生长和侵袭

背景与目的：let-7d与胶质瘤的关系尚不清楚,本研究探讨let-7d在人脑胶质瘤组织中表达及其对人脑胶质瘤U87细胞生物学特征的影响。方法：原位杂交法检测let-7d在人脑胶质瘤组织和正常脑组织中的表达,利用脂质体将let-7d寡核苷酸转入U87细胞,观察各组细胞生长、凋亡、侵袭情况。结果：人脑胶质瘤组织中let-7d较正常人脑组织低表达,转入let-7d寡核苷酸的U87细胞,生长减缓,凋亡增加,侵袭力减低。结论：微RNAlet-7d在胶质瘤的发生发展中可能起抑制作用。     

Gab2-Akt-ARK5通路在胶质瘤侵袭中的研究

  目的  探讨Gab2-Akt-ARK5通路在胶质瘤侵袭中的意义。  方法  采用免疫组织化学SP法检测90例胶质瘤组织中ARK5及Gab2表达。采用小RNA干扰转染LN-229细胞株,Western Blot检测瞬时转染后ARK5及Gab2表达。体外侵袭实验检测转染后侵袭能力变化及Western Blot检测Gab2下降后Akt和ARK5的磷酸化。  结果  胶质瘤组织中ARK5和Gab2免疫组织化学阳性结果呈正相关且在高级别胶质瘤（WHO分级为Ⅲ、Ⅳ级）中表达明显高于低级别胶质瘤（WHO分级为Ⅰ、Ⅱ级）。转染ARK5、Gab2、ARK5-Gab2及SCR质粒的LN-229细胞分别称siARK5/LN-229、siGab2/LN-229、siARK5-siGab2/LN-229和SCR/LN-229。其中siARK5干扰效率为70%,siGab2的干扰效率为75%。转染后,与SCR/LN-229相比,siARK5/LN-229中ARK5表达降低,siGab2/LN-229中Gab2表达降低,siARK5-siGab2/LN-229中ARK5和Gab2表达均降低。siARK5/LN-229和siGab2/LN-229侵袭并穿透Matrigel膜基质的细胞数均比对照组少（P < 0.01）,且siARK5-siGab2/LN-229细胞数减少更显著（P < 0.01）。在IGF-1刺激下,siGab2/LN-229中Akt和ARK5的磷酸化减弱。  结论  应用小RNA干扰技术降低ARK5或Gab2表达使LN-229细胞侵袭转移能力降低,同时Gab2表达降低抑制ARK5和Akt磷酸化,提示Gab2-Akt-ARK5通路参与胶质瘤细胞的侵袭。      

Snail蛋白表达与胃癌浸润转移的相关性研究

目的：研究Snail蛋白在胃癌中的表达与胃癌浸润转移的关系。方法：应用免疫组织化学sP法，检测Snail蛋白在87例胃癌和24例正常胃粘膜组织中的表达及其在细胞中的定位。结果：Snail蛋白高度表达于胃癌组织的细胞核、细胞质，正常胃粘膜组织中表达较少甚至不表达，阳性率分别为89．6％和29．1％，两者有统计学意义（P〈0．05）。Snail的表达与胃癌的组织学分化、浸润深度和淋巴结转移有关（P〈0．05）。结论：胃癌的侵袭转移与Snail蛋白的表达有关，Snail蛋白有可能成为胃癌侵袭转移的生物学标志。     

ADAM17 promotes glioma cell malignant phenotype

A disintegrin and metalloproteinase-17 (ADAM17) is involved in proteolytic ectodomain shedding of several membrane-bound growth factors and cytokines. The expression and activity of ADAM17 increase under some pathological conditions such as stroke and cancer. ADAM17 promotes neural progenitor cell migration and contributes to neurogenesis after stroke and breast cancer growth and invasion. In the present study, we sought to elucidate whether ADAM17 contributes to glioma progression. To this end, we examined the role of ADAM17 in the proliferation, invasion, and tube formation of U87 human glioma cells in vitro and tumor growth in vivo. Stable transfection of the U87 cell line with either a plasmid for over-expression of human ADAM17, or a siRNA to ADAM17 was employed in this study to establish high- or low-ADAM17 expression in glioma cells, respectively. For study of mechanism, the ADAM17 inhibitor TAPI-2 and the PI3K-AKT inhibitor LY294002 were used to counteract high-ADAM17 expression and the activated PI3K-AKT pathway, respectively. Proliferation of glioma cells were tested by thiazolyl blue tetrazolium bromide (MTT) assay, bromodeoxyuridine incorporation assay, growth curve, and sulforhodamine B assay. Matrigel invasion assays were used to assess the ability of U87 cells to penetrate the extracellular matrix (ECM). A Matrigel tube formation assay was performed to test capillary tube formation ability. EGFR-PI3K-Akt pathway activation in U87 cells under different ADAM17 expression levels were tested by Western blot. Our data show that ADAM17 promotes the U87 malignant phenotype by increased proliferation, invasion, angiogenesis, and in vivo tumor growth. Tumor growth in nude mice was significantly inhibited by ADAM17 inhibitor and A17-shRNA in vivo transfection. TGF-α, VEGF secretion, and VEGF expression was increased by ADAM17 and counteracted by ADAM17 siRNA, TAPI-2, and LY294002 in U87 cells. ADAM17 activated, whereas ADAM17 siRNA, TAPI-2, and LY294002 deactivated the EGFR-PI3K-AKT signal pathway, which correlated with U87 cell malignant phenotype changes. This study suggests ADAM17 contributes to glioma progression through activation of the EGFR-PI3K-AKT signal pathway.     

Osteopontin regulates human glioma cell invasiveness and tumor growth in mice

Human malignant glioma cells are characterized by local invasion. In the present study, we investigated the role of osteopontin (OPN) in the invasiveness of human glioma cells isolated from grade IV tumors. We found that the expression levels of OPN in these cell lines paralleled matrix metalloproteinase-2 (MMP-2) expression and cell invasiveness potential. When U87MG glioma cells (with a high-OPN expression level) were stably transformed with specific small hairpin RNA to knock down OPN expression, MMP-2 secretion, cell invasiveness, and tumor growth in implanted brains were dramatically reduced. Conversely, forced expression of OPN in GBM-SKH glioma cells (which expressed OPN at a low level) increased MMP-2 secretion, enhanced cell invasiveness, and increased tumor growth in a rodent xenograft model. Expression of OPN was associated with increased expression of vimentin and decreased expression of glial fibrillary acidic protein. Treatment of glioma cells with 5-aza-2′-deoxycytidine (5-aza-dC) suppressed OPN expression in a concentration-dependent manner. Suppression of OPN expression by 5-aza-dC was associated with reductions in MMP-2 secretion, vimentin expression, cell invasion, intravasation, and tumor growth. These data suggest that OPN may play important roles in regulating cell invasion in glioma cells and that 5-aza-dC may serve as a therapeutic agent for human gliomas.     

Snail promotes Cyr61 secretion to prime collective cell migration and form invasive tumor nests in squamous cell carcinoma

We previously identified genes associated with Snail-mediated squamous cell carcinoma (SCC) invasiveness, in which we observed significant elevation of Cyr61 expression. In this study, SCC cell lines overexpressing Cyr61 exhibited constitutive activation of Rho A and upregulated invasiveness without the disruption of homophilic cell attachment. Humoral Cyr61 enhanced further production of endogenous Cyr61 by SCC cells, which stimulated collective cell migration and the development of an invasive tumor nest. We propose a Cyr61-dependent model for the development of invasive SCC nest, whereby a subset of tumor cells that highly produce Cyr61 may direct other tumor cells to undergo collective cell migration, resulting in a formation of primary SCC mass.     

Sustained elevation of Snail promotes glial-mesenchymal transition after irradiation in malignant glioma

Background

Ionizing irradiation is an effective treatment for malignant glioma (MG); however, a higher rate of recurrence with more aggressive phenotypes is a vital issue. Although epithelial-mesenchymal transition (EMT) is involved in irradiation-induced cancer progression, the role for such phenotypic transition in MG remains unknown.

Methods

To investigate the mechanism of irradiation-dependent tumor progression in MG, we performed immunohistochemistry (IHC) and qRT-PCR using primary and recurrent MG specimens, MG cell lines, and primary culture cells of MG. siRNA technique was used for MG cell lines.

Results

In 22 cases of clinically recurrent MG, the expression of the mesenchymal markers vimentin and CD44 was found to be increased by IHC. In paired identical MG of 7 patients, the expression of collagen, MMPs, and YKL-40 were also elevated in the recurrent MGs, suggesting the The Cancer Genome Atlas-based mesenchymal subtype. Among EMT regulators, sustained elevation of Snail was observed in MG cells at 21 days after irradiation. Cells exhibited an upregulation of migration, invasion, numbers of focal adhesion, and MMP-2 production, and all of these mesenchymal features were abrogated by Snail knockdown. Intriguingly, phosphorylation of ERK1/2 and GSK-3β were increased after irradiation in a Snail-dependent manner, and TGF-β was elevated in both fibroblasts and macrophages but not in MG cells after irradiation. It was noteworthy that irradiated cells also expressed stemness features such as SOX2 expression and tumor-forming potential in vivo.

Conclusions

We here propose a novel concept of glial-mesenchymal transition after irradiation in which the sustained Snail expression plays an essential role.     

人脑胶质瘤组织培养的干细胞样细胞具有体外高侵袭能力

目的:分离培养人脑胶质瘤干细胞样细胞(glioma stem-like cell,GSLC),研究其体外侵袭力。方法:选取中国医科大学第一医院神经外科2008年10月至2009年1月间住院患者手术切除的脑胶质瘤组织8例,以无血清成球培养法培养胶质瘤细胞球;免疫细胞化学实验检测其CD133的表达;荧光免疫显微镜观察其分化后胶质细胞标志物GFAP和神经元标志物TU-20的表达;matrigel侵袭实验检测其侵袭力,并与原代脑胶质瘤细胞进行比较。结果:成功分离培养出人脑胶质瘤细胞球细胞,该细胞表达干细胞标志物CD133;能自我更新与增殖;诱导分化后,GFAP和TU-20均为阳性表达,提示其为GSLC。胶质瘤细胞球细胞侵袭细胞数显著多于原代胶质瘤细胞[(261.23±87.20)vs(116.08±63.88)个,P<0.01];此外,胶质瘤细胞球细胞穿过matrigel胶后可再次聚集成球状生长。结论:成功分离培养人脑胶质瘤组织中的GSLC,其体外具有较高的侵袭力,可能参与脑胶质瘤的侵袭和转移。     

Human giant larvae-1 promotes migration and invasion of malignant glioma cells by regulating N-cadherin

Human giant larvae-1 (Hugl-1) is a human homologue of Drosophila tumor suppressor lethal (2)-giant larvae and has been reported to be involved in the development of human malignancies. Previous studies performed by our group demonstrated that Hugl-1 inhibits glioma cell proliferation in an intracranial model of nude mice. However, the exact molecular mechanisms underlying the participation of Hugl-1 in glioma invasion and migration, and in the depolarizing process remain largely unknown. Utilizing the U251-MG cells with stable expression of Hugl-1, the present study used wound healing, Transwell invasion and western blot assays to explore the role and specific mechanism of Hugl-1 in glioma invasion and migration. The results of the present study demonstrated that overexpression of Hugl-1 decreased cell-cell adhesion and increased cell-cell extracellular matrix adhesion. In addition, overexpression of Hugl-1 promoted pseudopodia formation, glioma cell migration and invasion. The molecular mechanism of action involved the negative regulation of N-cadherin protein levels by Hugl-1. Overexpression or knockdown of N-cadherin partially suppressed or enhanced the effects of Hugl-1 on glioma cell migration and invasion, respectively. Furthermore, Hugl-1 inhibited cell proliferation, while promoting cell migration, which suggests that it may serve a two-sided biological role in cellular processes. Taken together, these results suggest that Hugl-1 promotes the migration and invasion of malignant glioma cells by decreasing N-cadherin expression. Thus, Hugl-1 may be applied in the development of targeted and personalized treatment.     

Human cytomegalovirus induces cellular tyrosine kinase signaling and promotes glioma cell invasiveness

Given our previous findings that human cytomegalovirus (HCMV) nucleic acids and proteins are expressed in human malignant glioma in vivo, we investigated cellular signaling events associated with HCMV infection of human glioma and astroglial cells. HCMV infection caused rapid activation of the phosphatidylinositol-3 kinase (PI-3K) effector AKT kinase in human astro-glial and fibroblast cells, and induced tyrosine phosphorylation of phospholipase Cγ (PLCγ). Co-immunoprecipitation experiments revealed association of the p85 regulatory subunit of PI-3K with a high-molecular weight protein phosphorylated on tyrosine, following short-term exposure to HCMV. In contrast to a previous report, we were unable to confirm the identity of this high-molecular weight protein as being the epidermal growth factor receptor (EGFR). Stimulation of glioma and fibroblast cell lines over-expressing EGFR with HCMV (whole virus) or soluble glycoprotein B did not induce tyrosine phosphorylation of the receptor, as did the genuine ligand, EGF. Furthermore, we found that expression levels of the human ErbB1-4 receptors were not rate-limiting for HCMV infection. Dispensability of EGFR function during early HCMV infection was substantiated by demonstration of viral immediate early gene expression in cells lacking the EGFR gene, indicating that HCMV may promote oncogenic signaling pathways independently of EGFR activation. Among non-receptor cellular kinases, HCMV infection induced phosphorylation of focal adhesion kinase (FAK) Tyr397, which is indispensable for integrin-mediated cell migration and invasion. HCMV-induced FAK activation was paralleled by increased extracellular matrix-dependent migration of human malignant glioma but not normal astro-glial cells, suggesting that HCMV can selectively augment glioma cell invasiveness. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.