Cell surface aggregation of elastin receptor molecules caused by suramin amplified signals leading to proliferation of human glioma cells

We have recently shown that glioma cell lines, as well as cells of human malignant gliomas in situ, synthesize tropoelastin. In addition, glioma cells degrade tropoelastin using metalloproteinase(s), and the resulting peptides, incapable of assembling in the extracellular fibers, interact with the 67-kDa cell surface elastin binding protein (EBP), to transduce signals leading to up-regulation of cell proliferation. In this report, we show that exposure to the polysulfonated bis-naphthylurea suramin causes accumulation of physiologically active EBP molecules on the cell surface of a panel of glioma cell lines (U87, MG, U251 MG, U343 MG-A, U373 MG, SF 126, SF188, SF539), which results in an increase of cellular attachment to elastin-coated dishes and in an efficient binding of radiolabeled tropoelastin. Moreover, 100–200 μM suramin stimulates [³H]-thymidine incorporation by those tropoelastin-producing glioma cell lines, but not by A 2058 melanoma cells, which do not produce elastin. Treatment of all glioma cell lines with 100 μM suramin consistently increased expression of cyclin A and its cyclin-dependent kinase, cdk 2, to levels reached following the exposure to exogenous elastin-degradation products (κ-elastin). Our data suggest that a suramin-stimulated accumulation of EBP molecules on the cell surface of glioma cells amplifies the elastin-derived signals, leading to their progression through the cell cycle. Received: 24 August 1998 / Revised, accepted: 29 September 1998     

lncRNA ZNF674-AS1过表达对胶质瘤U87细胞增殖、侵袭和迁移的影响

目的 探讨长链非编码RNA（lncRNA）ZNF674-AS1过表达对胶质细胞瘤增殖、侵袭、迁移的影响。方法 体外培养正常星形胶质细胞（HA1800）和胶质瘤细胞（A172、U251、U87、U373）,RT-PCR检测lncRNA ZNF674-AS1表达水平。将ZNF674-AS1 mimics转染U87细胞上调ZNF674-AS1表达,以转染阴性对照序列为对照,CCK8法检测细胞增殖能力,Transwell实验检测细胞侵袭和迁移能力。Starbase软件预测lncRNA ZNF674-AS1靶基因并应用双荧光素酶报告基因实验验证。结果 与正常星形胶质细胞（HA1800）比较,胶质瘤细胞（A172、U251、U87、U373）lncRNA ZNF674-AS1的表达水平均明显降低（P<0.05）,其中U87细胞表达水平最低。上调U87细胞lncRNA ZNF674-AS1表达,明显抑制U87细胞增殖、侵袭、迁移能力（P<0.05）。Starbase软件预测显示lncRNA ZNF674-AS1与性别决定区 Y 框蛋白 9（SOX9）基因有结合位点,双荧光素酶报告基因实验结果显示,SOX9基因是lncRNA ZNF674-AS1靶基因。上调U87细胞lncRNA ZNF674-AS1表达的同时沉默SOX9基因表达,明显增强U87细胞增殖、侵袭和迁移能力（P<0.05）。结论 胶质瘤lncRNA ZNF674-AS1呈低表达,可能通过靶向下调SOX9基因表达,促进胶质瘤细胞增殖、侵袭和迁移。     

过表达TBX2对胶质瘤细胞增殖和侵袭的影响

目的 探讨TBX2表达对胶质瘤细胞增殖、侵袭的影响。方法 采用RT-qPCR和免疫印迹法检测53例胶质瘤组织和瘤旁组织TBX2mRNA和蛋白表达水平。体外培养胶质瘤细胞（U251、U87和SHG-44）和正常星型胶质细胞（HA1800）,采用RT-qPCR和免疫印迹法检测细胞TBX2 mRNA和蛋白表达水平。构建TBX2过表达或低表达U251细胞株,分别采用WST-1法检测胶质瘤细胞增殖能力,Transwell实验检测细胞侵袭能力。结果 胶质瘤组织TBX2 mRNA和蛋白表达水平明显高于瘤旁组织（P<0.05）,而且,高级别胶质瘤TBX2表达水平显著高于低级别胶质瘤（P<0.05）。相比于人正常星型胶质细胞系HA1800,胶质瘤细胞系U251、U87、SHG-44细胞TBX2 mRNA和蛋白表达水平均明显增高（P<0.05）;而且,U251细胞TBX2表达水平显著高于U87和SHG-44细胞（P<0.05）,因此使用U251细胞进行后续实验。过表达TBX2显著增加U251细胞增殖和侵袭能力（P<0.05）,低表达TBX2显著抑制U251细胞增殖和侵袭能力（P<0.05）。结论 胶质瘤TBX2呈高表达,与胶质瘤增殖、侵袭能力有关。     

CREPT对胶质瘤U251细胞增殖、侵袭和迁移的影响及机制

目的 探讨肿瘤高表达细胞周期相关蛋白（CREPT）对胶质瘤U251细胞增殖、侵袭和迁移的影响及可能机制。方法 体外培养人胶质瘤细胞株U373、U251、A172、U87-MG、SHG44,并构建过表达或沉默CREPT的U251细胞;免疫印迹法检测蛋白表达水平;CCK-8法检测细胞增殖能力;Transwell实验检测细胞侵袭能力;细胞划痕实验检测细胞迁移能力。结果 U251细胞CREPT蛋白表达水平最高,SHG44细胞最低。沉默CREPT后,U251细胞增殖、侵袭和迁移能力明显下降（P<0.05）,p-Wnt和p-β-catenin蛋白表达水平下降（P<0.05）。过表达CREPT后,U251细胞增殖、侵袭和迁移能力明显增强（P<0.05）,p-Wnt和p-β-catenin蛋白水平明显升高（P<0.05）。Wnt/β-catenin通路抑制剂KYA1797K可逆转过表达CREPT对细胞增殖、侵袭和迁移的影响（P<0.05）。结论 CREPT可能通过激活Wnt/β-catenin通路促进胶质瘤U251细胞的增殖、侵袭和迁移。     

lncRNA SNHG16对胶质瘤U251细胞增殖、侵袭和迁移的影响

目的 探讨沉默长链非编码RNA核内小RNA宿主基因16（SNHG16）对胶质瘤U251细胞增殖、侵袭和迁移的影响。方法 实时荧光定量PCR检测正常胶质细胞HEB、NHA和胶质瘤细胞A172、U251、U87、SHG-4中SNHG16的表达。用siRNA沉默U251细胞SNHG16的表达,分为NC-siRNA组和SNHG16-siRNA组,CCK-8法检测细胞增殖,Transwell实验检测细胞侵袭,划痕实验检测细胞迁移。结果 与正常胶质细胞HEB和NHA比较,胶质瘤细胞A172、U251、U87和SHG-4的SNHG16表达水平明显升高（P<0.05）。与NC-siRNA组比较,SNHG16-siRNA组细胞增殖能力、细胞侵袭能力和细胞迁移能力均明显降低（P<0.05）。结论 SNHG16在胶质瘤细胞中高表达,特异性沉默SNHG16基因可以抑制胶质瘤细胞的增殖、侵袭和迁移能力。     

Knockdown of annexin 2 decreases migration of human glioma cells in vitro

Diffuse invasion of brain tissue is a major reason for the poor prognosis of patients with glioblastoma. Annexin 2, a member of the large annexin family of Ca2+ and membrane-binding proteins, is expressed at high protein levels in human gliomas and has been proposed as a marker of glioma malignancy, while its functional role in these tumours is unknown so far. The ability of annexin 2 to interact with the actin cytoskeleton, as well as its potential to bind invasion-associated proteases, suggests that it could participate in invasion-associated processes in human gliomas. Therefore, we analysed here functional consequences of RNA interference-mediated silencing of annexin 2 in U87MG and U373MG human glioma cell lines. While no impact of annexin 2 downregulation on proliferation and adhesion was observed, our analyses revealed that migration of U87MG and U373MG cells was significantly inhibited following annexin 2 depletion. This effect was not related to a compensatory increase of the related annexins 1 or 6. Our findings identify annexin 2 as a potential candidate involved in glioma invasion and support the potential of RNA interference as powerful tool in the decryption of glioma invasion mechanisms.     

STIP1对胶质瘤U251细胞增殖、侵袭和凋亡的影响

目的 探讨下调磷酸化应激诱导蛋白1（STIP1）表达对胶质瘤U251细胞增殖、侵袭和凋亡的影响,及其对JAK2/STAT3信号通路的调控作用。方法 免疫印迹法检测体外培养的正常胶质细胞（SVG）和人胶质瘤细胞（U251、U87和U37）STIP1蛋白表达水平。NC-siRNA或STIP1-siRNA质粒转染U251细胞,CCK-8法检测U251细胞增殖;Transwell实验检测U251细胞侵袭能力;流式细胞术检测U251细胞凋亡率;免疫印迹法检测JAK2/STAT3信号通路蛋白表达水平。结果 与正常胶质细胞SVG比较,胶质瘤细胞U251、U87和U373的STIP1蛋白表达水平均明显增高（P<0.05）。与NC-siRNA组比较,STIP1-siRNA组STIP1蛋白表达水平、细胞增殖活力和细胞侵袭力明显明显降低（P<0.05）,细胞凋亡率明显增高（P<0.05）,而且,p-JAK2和p-STAT3蛋白表达水平明显降低（P<0.05）。结论 STIP1在胶质瘤细胞中呈高表达,抑制STIP1表达可以抑制胶质瘤细胞的增殖和侵袭、促进凋亡,机制可能与抑制JAK2/STAT3信号通路有关。     

Activation of NMDA receptor of glutamate influences MMP-2 activity and proliferation of glioma cells

Glioblastoma multiforme (GBM) is the most common malignant glioma, which has high proliferative rate and an extremely invasive phenotype. Major limitations in the effective treatment of malignant gliomas are the proliferation and infiltration into the surrounding brain tissue. Although studies have shown that various stimuli promote glioma cell proliferation and invasion, the underlying mechanisms remain largely unknown. Glioma cells secrete significant amount of glutamate into surrounding tissue and intracellular signaling is thought to be initiated upon glutamate-induced modulation of the ion channels in GBM cells. The objective of the study was to investigate the effect of activation of NMDA (N-methyl-d-aspartate) receptors of glutamate on gelatinase subfamily MMPs and on proliferation of glioma cells. U251MG and U87MG cell lines were maintained in Dulbecco’s Modified Eagle’s Medium. Proliferation assay was investigated by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, a yellow tetrazole (MTT) assay. Matrix metalloproteinase (MMP)-2 and MMP-9 activity was investigated by gelatin zymography assay. We demonstrate that activated NMDA receptors (NMDAR) increased the activity of MMP-2 only in U251MG glioma cells at concentrations of 100 and 200 μM and increased the proliferation of both U87MG and U251MG glioma cells at concentrations of 50, 100, 150 and 200 μM. Inhibition of NMDAR using MK-801, a non-competitive antagonist of the NMDAR, significantly inhibited the effect of activation of NMDAR on MMP-2 activity and on proliferation. We conclude that NMDA receptor activation has role in activity of MMP-2 and proliferation of glioma cells.     

lncRNA LINC00689靶向调控miRNA-634促进胶质瘤U251细胞增殖、侵袭和迁移

目的 探讨长链基因间非蛋白编码RNA689（LINC00689）对胶质瘤细胞增殖、侵袭和迁移的影响。方法 RT-PCR实验检测正常胶质细胞HEB、胶质瘤细胞系A172、U251、U87、SHG-4中LINC00689和miRNA-634的表达。将si-NC、si- LINC00689、miRNA-634 mimics、miRNA-NC、si- LINC00689+anti-miRNA-NC、si- LINC00689+anti-miRNA-634质粒转染至U251细胞中;CCK-8实验检测细胞增殖、Transwell实验检测细胞侵袭和迁移。结果 与正常胶质细胞HEB比较,胶质瘤细胞系A172、U251、U87和SHG-4的LINC00689表达水平较高,而miRNA-634表达水平较低（P<0.05）。与si-NC组比较,si-LINC00689组LINC00689表达水平、细胞增殖活力、侵袭和迁移细胞数明显较低（P<0.05）。与miRNA-NC组比较,miRNA-634 mimics组miRNA-634表达水平明显增高（P<0.05）,细胞增殖活力、侵袭和迁移细胞数明显降低（P<0.05）。与si- LINC00689+anti-miRNA-NC组比较,si- LINC00689+anti-miRNA-634组细胞增殖活力、侵袭和迁移细胞数明显增高（P<0.05）。结论 LINC00689可以促进胶质瘤细胞的增殖、侵袭和迁移,其机制可能与靶向调控miRNA-634有关。     

下调RNA甲基化酶NSUN2表达对脑胶质瘤U87细胞增殖、侵袭、迁移的影响

目的 探讨下调NOP2/Sun RNA甲基转移酶家族成员2(NSUN2)表达对脑胶质瘤细胞增殖、侵袭、迁移的影响。方法体外培养正常胶质细胞HEB、胶质瘤细胞系（A172、U251、U87）,免疫印迹法检测NSUN2蛋白表达水平;用shNSUN2慢病毒（sh-NSUN2组）及shRNA scramble慢病毒（sh-CON组）感染U87细胞下调NSUN2表达,用CCK-8法检测细胞增殖活力,Transwell实验检测细胞侵袭和迁移。结果 与正常胶质细胞HEB相比,胶质瘤细胞系A172、U251、U87的NSUN2蛋白表达量均明显增高（P<0.05）。与sh-CON组比较,sh-NSUN2组NSUN2蛋白表达水平、细胞增殖活力、侵袭能力和迁移能力均明显降低（P<0.05）。结论 胶质瘤NSUN2呈高表达,下调其表达明显抑制胶质瘤细胞增殖、侵袭和迁移。     

Hax-1对胶质瘤细胞增殖、迁移和侵袭的作用

目的 探讨造血干细胞特异性相关结合蛋白-1(Hax-1)对胶质瘤细胞增殖、迁移和侵袭的影响.方法 选择2018年9月至2019年6月手术切除并得到术后病理证实的胶质瘤组织35例和颅脑损伤内减压术切除的正常脑组织35例,采用qRT-PCR检测Hax-1 mRNA水平;同时检测胶质瘤细胞系(U87、A172、T98及U34...     

Notch1通路与胶质瘤细胞管道形成能力相关性研究

目的探索胶质瘤细胞来源的管道(glioma clls derived vessels,GCDV)的形成机制。方法将胶质瘤细胞株U87、U251、U373、SF295、T98G、SKMG-4和C6进行体外三维培养,观察其管道形成能力。Western blot检测各个胶质瘤细胞株Notch1、Dll4蛋白的表达情况。结果三维培养C6细胞单个视野下(100×)的平均管道数(25.2±5.0)个,U373为(36.4±3.20)个,U87为(19.0±2.2)个,T98G为(12.6±2.4)个,SF295为(4.0±2.)个,U251为(0.2±0.4)个,SKMG-4为0。Notch1在U87、U251、T98G、SF295、SKMG-4、C6、U373表达相关密度分别为0.34、0.21、0.79、0.04、0.28、1.75、1.19,与管道形成能力显著相关(r=0.778,P=0.019);Dll4表达相关密度与管道形成能力不相关(r=0.635,P=0.062)。结论 Notch1蛋白表达与细胞株管道形成能力密切相关,而Dll4蛋白的表达与细胞株管道形成能力有待进一步探索。     

FRK通过N-cadherin／E-cadherin胶质瘤细胞侵袭和迁移途径抑制

目的探讨抑癌基因FRK（Fyn-relatedkinase）影响胶质瘤细胞侵袭和迁移的机制。方法将真核表达质粒pcDNA3．0-FRK和对照质粒pcDNA3．0转入人胶质瘤U251细胞中,westernblot技术检测FRK／N．cadherin／E—cadherin蛋白表达,细胞划痕试验检测细胞迁移能力,Transwell侵袭实验检测细胞侵袭能力。结果与对照组比较,转染pcl）NA3．0-FRK质粒24h后U251细胞侵袭能力下降47％、迁移能力下降64％,差异均有统计学意义（P〈0．01）;转染pcDNA3．0-FRK可以明显增加N—cadherin／E—cadherin的表达。结论FRK可以通过增加N．cadherin／E—cadherin的表达,进而抑制胶质瘤细胞侵袭和迁移能力。     

Inhibitory Effect of IFN-��, on the Antitumor Activity of Celecoxib in U87 Glioma Model

Objective

Interferon-β, (IFN-β) has been used in the treatment of cancers. Inhibition of the enzyme cyclooxygenase (COX) with celecoxib had a significantly suppressive effect on tumor growth, angiogenesis, and metastasis in a variety of tumors. The aim of this study was to elucidate the antiglioma effect of combined treatment with IFN-β and celecoxib in U87 glioma model.

Methods

The in vitro effects of IFN-β (50-1,000 IU/mL) and celecoxib (50-250 µM) alone or combination of both on the proliferation and apoptosis of U87 cells were tested using MTT assay, FACS analysis and DNA condensation. To determine the in vivo effect, nude mice bearing intracerebral U87 xenograft inoculation were treated with IFN-β intraperitoneally (2×10⁵ IU/day for 15 days), celecoxib orally (5, 10 mg/kg) or their combination.

Results

IFN-β or celecoxib showed an inhibitory effect on the proliferation of U87 cells. When U87 cells were treated with IFN-β and celecoxib combination, it seemed that IFN-β interrupted the antiproliferative and apoptotic activity of celecoxib. No additive effect was observed on the survival of the tumor bearing mice by the combination of IFN-β and celecoxib.

Conclusion

These results suggest that IFN-β seems to inhibit the antiglioma effect of celecoxib, therefore combination of IFN-β and celecoxib may be undesirable in the treatment of glioma.     

Invasiveness of human glioma cell lines in vitro: Relation to tumorigenicity in athymic mice

Summary Five established cell lines derived from human anaplastic astrocytomas or glioblastoma multiforme were tested for invasiveness into precultured chick heart fragments in vitro. Four of the cell lines (U118 MG, D54 MG, U373 MG and A172) were strongly invasive into the heart tissue. A fifth cell line, U251 MG sp, which was only tumorigenic at doses of greater than 1×10⁸ cells in athymic mice, was non-invasive in vitro. One line, A172, was invasive but not tumorigenic in athymic mice, although a related invasive subline, D54 MG, at later passage levels was tumorigenic even at low cell doses. Invasion of the glioma cells was characterized by progressive and irreversible replacement of the precultured chick heart tissue. Both by light and transmission electron microscopy, a similar pattern of invasion was observed as earlier found with experimental rat glioma cells in the same system. Some human cell lines established from human gliomas retain invasive properties after a prolonged culture period in vitro.Supported by the Norwegian Cancer Society (LIdeR), and by grants CA 11898, CA32672, and NS 20023 (DDB)     

RNA干涉CD44基因抑制脑胶质瘤细胞U251的增殖与侵袭性研究

目的通过合成靶向分化抗原簇44(CD44)基因的siRNA片段,下调CD44在脑胶质瘤细胞U251中的表达,揭示其在胶质瘤增殖、迁移和侵袭中所起的作用。方法根据CD44基因序列设计并合成的siRNA片段转染U251细胞,利用荧光实时定量(qRT-PCR)检测细胞中CD44基因mRNA水平的变化;蛋白印迹实验(Western blot)检测CD44基因蛋白水平的变化;四甲基偶氮唑蓝染色(methyhhiazolyl tetrazolium,MTT)法检测U251细胞增殖;单细胞划痕愈合实验、Transwell小室侵袭实验检测U251细胞的迁移与侵袭能力变化。结果体外合成的CD44-siRNA能有效抑制U251细胞中CD44基因在mRNA水平与蛋白水平的表达(P0.05),并抑制细胞的增殖(P0.05)和迁移侵袭能力(P0.05)。结论 CD44-siRNA能够有效抑制U251脑胶质瘤细胞的增殖及其迁移侵袭力,为以CD44为靶点的肿瘤基因治疗奠定了基础。     

白藜芦醇对胶质瘤U87细胞迁移和侵袭能力的影响

目的探讨白藜芦醇对胶质瘤U87细胞迁移和侵袭能力的影响和作用机制。方法采用四唑盐(MTT)比色实验检测胶质瘤U87细胞经不同浓度白藜芦醇作用24 h、48 h、72 h后生存率的变化;细胞划痕试验和transwell侵袭试验检测白藜芦醇对胶质瘤U87细胞迁移和侵袭能力的影响;明胶酶谱法分析白藜芦醇对细胞基质金属蛋白酶(MMP)活性的改变。结果 MTT法显示一定浓度的白藜芦醇可抑制U87细胞生长,并随着浓度的增加和作用时间的延长而明显增强(P<0.05);与对照组比较,经白藜芦醇作用后U87细胞迁移和侵袭能力明显降低,MMP-2分泌减少。结论白藜芦醇可有效抑制胶质瘤U87细胞迁移和侵袭能力,其机制可能与白藜芦醇降低细胞MMP-2活性相关。     

High concentrations of cannabinoids activate apoptosis in human U373MG glioma cells

Cannabinoids bind to two G-protein-coupled receptors, CB1 and CB2, expressed by neurons and cells of the immune system, respectively. Glioma cells (astrocyte-derived brain tumor cells) express cannabinoid receptors, and numerous in vitro and in vivo studies performed in rodents have concluded that apoptosis could be induced by cannabinoids in these cells. Whether this also applies to human cells is controversial; we, therefore, assessed the effect of cannabinoids on human glioma cell viability with the human astrocytoma cell line U373MG. We report here that U373MG human glioma cells are sensitive only to high concentrations of cannabinoids (>5 microg/ml for Delta(9)-THC). Similar concentrations of the compounds promoted a rapid activation of extracellular-regulated kinase and c-Jun NH2-terminal kinase, suggesting that cannabinoid receptors are functional in U373MG cells. Nevertheless, these kinases are not involved in cannabinoid-induced cell death in U373MG cells, insofar as blocking their activation with specific inhibitors does not reduce cell death. CB1 is expressed in U373MG cells and is involved in cannabinoid-induced cell death, in that blocking its activation with a specific antagonist (AM251) almost totally prevented cell death following incubation of the cells with Delta(9)-THC. In addition, as already reported, some cannabinoids may have modest proproliferative properties in U373MG cells. Human U373MG glioma cells are sensitive only to very high, pharmacologically irrelevant concentrations of cannabinoids, so it seems unlikely that cannabinoids would constitute promising molecules for treating malignant astrocytoma; they do not induce glioma cell death at doses that could be applied safely to humans.