人脑胶质瘤高表达Snail促进肿瘤细胞的侵袭

目的:观察Snail蛋白在人脑胶质瘤组织中的表达情况,探讨Snail表达对人脑胶质瘤U251细胞侵袭的影响。方法:收集首都医科大学附属北京天坛医院及北京安贞医院神经外科手术切除的脑胶质瘤组织65例,应用免疫组织化学S-P法检测人脑胶质瘤组织中Snail的表达。体外化学合成Snail序列特异性小干扰RNA(Snail-siRNA),应用脂质体介导转染U251细胞;RT-PCR、Western blotting检测转染后U251细胞中Snail mRNA和蛋白、E-cadherin蛋白表达水平变化,并采用Transwell小室检测转染后U251细胞侵袭能力的变化。结果:与正常脑组织相比,人脑胶质瘤组织中Snail蛋白阳性表达率明显增强(66.2%vs0,P<0.01),并且Ⅰ～Ⅱ级的胶质瘤组织阳性Snail阳性率明显低于Ⅲ～Ⅳ级(44.8%vs83.3%,P<0.01)。Snail-siRNA转染抑制U251细胞中Snail mRNA和蛋白的表达。Snail-siRNA转染组U251细胞中E-cadherin蛋白的表达明显高于Ctrl-siRNA组与未转染组(0.64±0.21vs0.15±0.16,0.21±0.19,P<0.01)。Snail-siRNA转染显著抑制U251细胞的侵袭(87.0±2.4vs140.0±4.9,136.0±5.3;P<0.05)。结论:人脑胶质瘤组织高表达Snail蛋白,siRNA干扰Snail蛋白的表达可抑制胶质瘤U251细胞的侵袭。     

沉默circRNA hsa_circ_0103809表达抑制胶质瘤细胞增殖和侵袭

目的:通过研究环状RNA(circRNA) hsa_circ_0103809对胶质瘤细胞增殖和侵袭的影响,来明确 hsa_circ_0103809在胶质瘤进展中所起到的作用。方法:采用qRT-PCR检测hsa_circ_0103809在胶质瘤细胞系U251和正常脑胶质细胞系HEB中表达水平的差异。U251细胞经小干涉RNA（siRNA）介导下调hsa_circ_0103809的表达水平后,采用qRT-PCR检测沉默效率。将U251细胞分为两组,即siRNA-circ沉默实验组和siRNA-NC阴性对照组,实验组转染hsa_circ_0103809的siRNA,对照组转染siRNA对照序列,后续分别使用CCK-8实验、EdU实验和Transwell实验检测hsa_circ_0103809的表达下调对U251细胞增殖和侵袭的影响。结果:hsa_circ_0103809在胶质瘤U251细胞中的表达水平明显高于正常脑胶质HEB细胞（P＜0.01）。在U251细胞中转染siRNA-hsa_circ_0103809后其表达水平明显降低（P＜0.01）。CCK-8实验结果显示,沉默hsa_circ_0103809的表达后,U251细胞在24 h和48 h的光密度（OD）值和对照组无明显差异,但实验组在72 h的OD值明显低于对照组（P＜0.01）。EdU实验结果显示,沉默hsa_circ_0103809的表达后,U251细胞的增殖能力较对照组明显降低（P＜0.01）。Transwell实验结果显示,沉默hsa_circ_0103809的表达后,U251细胞的侵袭能力较对照组明显降低（P＜0.001）。结论:hsa_circ_0103809在胶质瘤U251细胞中高表达,沉默hsa_circ_0103809表达可显著抑制胶质瘤细胞的增殖和侵袭。     

Galectin-3调控Wnt信号通路对脑胶质瘤细胞凋亡的影响

目的:半乳糖凝集素-3（Galectin-3）调控Wnt信号通路对人脑胶质瘤细胞凋亡的影响。方法:RT-PCR及Western blot检测人脑胶质瘤组织中Galectin-3的mRNA和蛋白表达;Western blot检测人脑胶质瘤U251、U87、SHG-44细胞中Galectin-3的蛋白表达;将Galectin-3的特异性siRNA(Galectin-siRNA)转染人脑胶质瘤U87细胞,Western blot、流式细胞术分别检测转染48 h后Galectin-3、Wnt5a、β-catenin和Cleaved caspase3蛋白表达及细胞凋亡率。结果:Galectin-3在人脑胶质瘤组织mRNA和蛋白表达均显著高于瘤旁组织（P＜0.01）;U251、U87、SHG-44细胞中Galectin-3蛋白表达从高到低为U87>U251>SHG-44,选择U87细胞作为后续研究;Galectin-3-siRNA1的Galectin-3蛋白表达最低,选择作为后续研究;NC-siRNA组细胞凋亡率、Cleaved caspase3、Wnt5a、β-catenin蛋白表达与对照组差异不显著（P＞0.05）,与对照组比较,Galectin-3-siRNA组细胞凋亡率明显升高,Cleaved caspase3蛋白表达明显升高,Wnt5a和β-catenin蛋白表达明显降低（P＜0.01）。结论:沉默Galectin-3表达可诱导人脑胶质瘤细胞凋亡,机制可能与Wnt信号通路的下调有关。     

人脑胶质瘤细胞株中RIZ1基因启动子甲基化状态的研究

检测4种人脑成胶质细胞瘤细胞株中成视网膜细胞瘤蛋白结合锌指结构基因1（retinoblastoma protein-interacting zinc finger gene1,RIZ1）基因启动子区的甲基化状态,进一步认识RIZ1在胶质瘤发病机制中的作用。方法：应用甲基化特异性PCR法（methylation specific PCR,MSP）检测4种人脑成胶质细胞瘤细胞株U87、U251、A172和T98中RIZ1基因启动子区的甲基化水平,其中U87细胞发生甲基化,被选为后续实验对象。RT-PCR检测U87细胞经5-Aza-CdR处理前后RIZ1 mRNA表达量的变化,MTT检测5-Aza-CdR对U87细胞生长增殖的影响。结果：4种人脑成胶质细胞瘤细胞株中U87和U251细胞中检测到RIZ1基因启动子区域发生甲基化;U87细胞经5-Aza-CdR处理后其RIZ1 mRNA的表达量上调;MTT法检测显示5-Aza-CdR能抑制U87的生长增殖,且与5-Aza-CdR的浓度和作用时间呈负相关。结论：RIZ1基因启动子高甲基化是人脑成胶质细胞瘤细胞株中RIZ1基因表达下调的重要机制。     

PTEN在人脑胶质瘤细胞中的表达及其对细胞增殖的影响

背景与目的:PTEN基因的缺失及突变与多种肿瘤有关,而脑胶质瘤是与PTEN基因变异关系最为密切的恶性肿瘤之一.本研究旨在观察PTEN基因对人脑胶质瘤细胞生物学特性的影响,为PTEN用于胶质瘤基因治疗提供科学的实验依据.方法:(1)应用RT-PCR方法扩增人脑胶质瘤细胞U251、SHG-44中PTEN基因,序列测定分析.(2)采用阳离子聚合物转染试剂,将携带野生型PTEN基因的重组真核表达载体质粒转染至胶质瘤细胞,G418筛选出稳定转染的细胞并扩增培养.通过细胞形态学、细胞生长曲线观察PTEN基因表达对细胞形态和增殖的影响,应用Western blot、免疫细胞化学法检测相关蛋白的表达.结果:(1)胶质瘤细胞U251和SHG-44的PTEN mRNA分别存在着突变型、缺失型两种表达方式.(2)稳定转染的U251和SHG-44细胞株的生长曲线显示细胞增殖明显受抑制,第7天细胞计数分别为未转染对照组细胞数的39.1%、27.8%;Westem blot显示稳定转染细胞株有外源性PTEN蛋白的表达;细胞免疫化学法显示胶质纤维酸性蛋白(glial fibrillary acidic protein,GFAP)表达量增加,从而表现出对细胞形态影响的差异,稳定转染的U251细胞出现向星形细胞分化的特征,SHG-44细胞形态转染前后无明显改变.结论:恢复野生型PTEN基因表达对胶质瘤细胞存在差异性的诱导分化作用.     

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。     

EZH2基因沉默对人脑胶质瘤U251细胞增殖和凋亡影响的研究

目的:研究RNA干扰技术抑制zeste基因增强子人类同源物2(EZH2)的表达对人胶质瘤U251细胞增殖及凋亡的影响.方法:构建靶向EZH2基因的shRNA质粒并转染至U251细胞中,采用RT-PCR和蛋白质印迹法检测EZH2 mRNA和蛋白的表达情况,利用四甲基偶氮哇盐(MTT)实验和Annexin V-FITC/PI流式细胞术实验观察转染后U251细胞增殖和凋亡情况.结果:靶向EZH2基因的shRNA质粒成功抑制了U251细胞EZH2基因的表达,mRNA和蛋白表达抑制率分别为56.00％和88.73％;转染shRNA EZH2后,U251细胞的生长受到明显抑制(P＜0.01),在转染96 h后,生长抑制率达35.79％;转染48 h后,U251细胞早、晚期凋亡率分别为(26.59±0.83)％和(38.63±0.80)％,较阴性质粒组和空白对照组均增加,以晚期明显,差异有统计学意义,P＜0.01.结论:EZH2基因的沉默能有效抑制胶质瘤U251细胞的增殖、促进其凋亡,提示EZH2可能成为胶质瘤基因治疗的新靶点.     

SLC22A18基因转染人胶质瘤U251细胞对放疗敏感性的影响

目的：探讨SLC22A18基因转染人胶质瘤U251细胞对放疗敏感性的影响。方法：用脂质体介导的转染技术将pIRES2-EGFP-SLC22A18表达重组质粒导入U251细胞,通过逆转录-聚合酶链反应（RT-PCR）和免疫印迹（Western blot）检测SLC22A18基因和蛋白的表达。U251细胞分为4组：对照组、转染组、放疗组和转染联合放疗组。集落形成实验检测各组U251细胞集落形成数,用四甲基偶氮唑盐微量酶反应比色法（MTT法）和流式细胞仪检测各组U251细胞生长抑制率和凋亡率,进一步应用裸鼠皮下荷瘤模型观察脂质体介导的pIRES2-SLC22A18表达重组质粒转染U251细胞对放疗敏感性的影响。结果：重组质粒转染组通过RT-PCR和Western blot证实了SLC22A18基因和蛋白在U251细胞中表达。集落形成实验检测发现SLC22A18基因对U251细胞的集落形成数为（60.6±5.2）个,当放射剂量为3、6和9 Gy时,U251细胞的集落形成数分别为（30.0±3.6）、（13.0±3.0）和（4.0±1.0）个。MTT检测发现SLC22A18基因对U251细胞的生长抑制率为（80.12±5.75）%。当放射剂量为3、6和9 Gy时,U251细胞的生长抑制率分别为（17.05±4.24）%、（17.34±1.62）%和（18.71±4.59）%。当SLC22A18基因与放疗（3、6和9 Gy）联合作用时,抑制率分别为（81.45±5.32）%、（90.45±1.65）%和（92.62±2.12）%。SLC22A18基因转染所产生的U251细胞凋亡率为17.68%。放疗（3、6和9 Gy）引起的细胞凋亡率分别为4.64%、4.87%和5.42%。当SLC22A18基因与放疗（3、6和9 Gy）联合作用时,凋亡率分别为18.42%、21.48%和23.92%。体内实验结果显示,SLC22A18基因对U251细胞6 Gy照射的抑瘤率比较为1.81。结论：SLC22A18基因转染增加了人胶质瘤U251细胞对放疗的敏感性。     

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。     

STAT1基因对胶质瘤细胞系U251细胞周期的影响及其机制

 目的 探讨信号转导与转录激活因子1（STAT1）对胶质瘤细胞系U251细胞周期的影响及其机制。方法 利用LipofectamineTM2000转染试剂体外瞬时将pcDNA3.1-STAT1转染入胶质瘤细胞系U251，将细胞分为Mock组（无转染）、空载组（转染pcDNA3.1）和STAT1组（转染pcDNA3.1-STAT1），采用Western blot法检测胶质瘤U251细胞中STAT1表达水平，MTT法检测转染STAT1的U251细胞增殖活性，流式细胞仪检测细胞周期指标，划痕实验检测细胞迁移指标，通过Western blot法检测转染细胞中P53、P21、bcl-2、Caspase-8的表达水平及变化趋势。结果 与Mock和空载组相比，STAT1组中STAT1蛋白表达量明显增高（P<0.05），细胞增殖明显减慢（P<0.05），G₀/G₁期细胞比例明显升高，细胞的迁移能力明显下降； P53、P21、Caspase-8表达明显增强（P<0.05），bcl-2表达明显减弱（P<0.05）。结论 高表达的STAT1对人脑胶质瘤U251细胞具有抑制增殖或促进凋亡的作用，并且STAT1可调控多分子信号转导通路，对脑胶质瘤的发生和发展起到了关键的作用。     

抑制LITAF基因对人脑胶质母细胞瘤U251细胞增殖、凋亡和放疗敏感度的影响

 目的 分析人脑胶质母细胞瘤组织中LITAF基因mRNA表达情况,并通过抑制人脑胶质母细胞瘤U251细胞中LITAF基因表达,观察其对U251细胞增殖、凋亡和放疗敏感度的影响。方法 分析TCGA数据库中人脑胶质母细胞瘤组织中LITAF基因mRNA表达;通过RNAi抑制U251细胞中LITAF基因表达,采用胸腺嘧啶核苷类似物（EDU）检测U251细胞增殖变化,流式细胞仪分析U251细胞凋亡的变化,克隆形成实验和流式细胞分析U251细胞放疗敏感度的变化。 结果 TCGA数据库分析结果显示人脑胶质母细胞瘤组织LITAF表达显著高于正常脑组织;抑制LITAF表达后,U251细胞的增殖和凋亡未见明显变化,但在电离辐射后,LITAF抑制组U251细胞凋亡显著低于对照组,克隆形成显著高于对照组,对放疗敏感度减弱。结论 LITAF基因高表达于人脑胶质母细胞瘤组织,抑制人脑胶质母细胞瘤U251细胞中LITAF基因表达不影响细胞的增殖和凋亡,但显著降低细胞的放疗敏感度。     

Antitumor effect of dehydroxymethylepoxyquinomicin, a small molecule inhibitor of nuclear factor-κB, on glioblastoma

Glioblastoma is the most malignant type of brain tumor. Despite recent advances in therapeutic modalities, the prognosis of glioblastoma remains very poor. Recent studies have indicated that RelA/nuclear factor (NF)-κB is consistently activated in human glioblastoma. In this study, we searched for a new treatment modality for glioblastoma, by examining the effects of dehydroxymethylepoxyquinomicin (DHMEQ), a unique small molecule inhibitor of NF-κB. Addition of DHMEQ to cultured human glioblastoma cells inhibited the nuclear translocation of RelA. It also reduced the growth rate of human glioblastoma cells significantly in 6 cell lines and modestly in 3 among 10 cell lines examined. Then, we performed further analyses using 3 sensitive cell lines (U87, U251, and YKG-1). The growth retardation was accompanied by G2/M arrest in vitro. Increased apoptosis was observed in U87 and YKG-1, but not U251 cells after DHMEQ treatment. Then, we tested the efficacy of DHMEQ in chemoprevention through the use of a nude mouse model. Subcutaneous tumors formed by U87 or U251 cells were reduced by ～40% in size by intraperitoneal administration of DHMEQ started immediately after implantation of the cells. DHMEQ treatment achieved statistically significant improvements in survival curves of mice intracranially implanted with U87 or U251 cells. Histological analysis revealed increased areas of necrosis, increased numbers of collapsed microvessels, decreased nuclear immunoreactivity of RelA, and decreased immunoreactivity of urokinase-type plasminogen activator in the DHMEQ-treated U87 tumor tissues. These results suggest that the targeting of NF-κB by DHMEQ may serve as a promising treatment modality in glioblastoma.     

Cancer stem-like cells of glioblastoma characteristically express MMP-13 and display highly invasive activity

Glioblastoma is the most malignant type of primary brain tumor that has been shown to contain a small population of cancer stem cells. Recent studies have suggested that cancer stem cells cause tumor recurrence based on their resistance to radiotherapy and chemotherapy. Although the highly invasive nature of glioblastoma cells is also implicated in the failure of current therapies, it is not clear whether cancer stem cells are involved in invasiveness. In this study, we isolated tumor sphere-forming cells bearing cancer stem-like characteristics such as self-renewal, multipotency, drug-resistibility, and in vivo tumorigenicity, from the human glioblastoma cell line U251, under serum-free neural stem cell culture condition, and assessed their migratory and invasive ability. These cells showed enhanced migratory and invasive ability on both Matrigel and organotypic brain slices compared to parental U251 cells. The expression of matrix metalloproteinase (MMP)-13 was specifically expressed in tumor sphere-forming cells derived from U251 and primary human glioma cells. Knockdown of MMP-13 expression by shRNA suppressed the migration and invasion of these cells. The results suggest that the highly invasive potential of cancer stem cells depends on MMP-13 enzymatic activity, thus MMP-13 might be a potential therapeutic target for glioblastomas.     

LRRC4基因表达能降低胶质母细胞瘤细胞系U251的生长和成瘤潜能

背景与目的：LRRC4是作者最近克隆的一个新基因,该基因在原发性脑肿瘤活检标本中明显表达下调。本研究旨在研究LRRC4基因是否具有抑制脑肿瘤生长的能力。方法：LRRC4基因的全长编码区被亚克隆至表达载体pcDNA3．1中,应用脂质体转染的方法将重组的质粒载体导入胶质母细胞瘤细胞系U251,经G418筛选,建立稳定表达LRRC4基因的U251的细胞系。采用细胞增殖实验、软琼脂实验、肿瘤形成实验来考察LRRC4基因表达对于细胞生长和肿瘤形成的影响。结果：经过脂质体转染和筛选,建立了稳定表达LRRC4全长编码区的U251细胞系,用于进一步实验。比较未转染组和转染空白载体组,Northern blot实验证实转染了LRRC4基因的细胞LRRC4 mRNA的表达增强。细胞增殖一定时间后,转染LRRC4基因的细胞较未转染细胞的生长速度明显减慢,克隆形成率明显降低。将这些细胞注射入无胸腺裸鼠体内,40天后处死裸鼠,测量肿瘤大小,结果显示,转染LRRC4基因的细胞形成的肿瘤明显小于对照组。结论：LRRC4基因可转染于人脑胶质母细胞瘤细胞系U251。LRRC4在U251细胞的表达有抑制瘤细胞增殖和抑制裸鼠移植瘤的形成和生长的作用。     

Suppression of STIM1 inhibits human glioblastoma cell proliferation and induces G0/G1 phase arrest

Background

Depletion of calcium (Ca²⁺) from the endoplasmic reticulum (ER) activates the ubiquitous store-operated Ca²⁺ entry (SOCE) pathway which sustains long-term Ca²⁺ signals and is critical for cellular functions. Stromal interacting molecule 1 (STIM1) serves a dual role as an ER Ca²⁺ sensor and activator of SOCE. Aberrant expression of STIM1 could be observed in several human cancer cells. However, the role of STIM1 in regulating tumorigenesis of human glioblastoma still remains unclear.

Methods

Expression of STIM1 protein in a panel of human glioblastoma cell lines (U251, U87 and U373) in different transformation level were evaluated by Western blot method. STIM1 loss of function was performed on U251 cells, derived from grade IV astrocytomas-glioblastoma multiforme with a lentvirus-mediated short harpin RNA (shRNA) method. The biological impacts after knock down of STIM1 on glioblastoma cells were investigated in vitro and in vivo.

Results

We discovered that STIM1 protein was expressed in U251, U87 and U373 cells, and especially higher in U251 cells. RNA interference efficiently downregulated the expression of STIM1 in U251 cells at both mRNA and protein levels. Specific downregulation of STIM1 inhibited U251 cell proliferation by inducing cell cycle arrest in G0/G1 phase through regulation of cell cycle-related genes, such as p21^Waf1/Cip1_, cyclin D1 and cyclin-dependent kinase 4 (CDK4), and the antiproliferative effect of STIM1 silencing was also observed in U251 glioma xenograft tumor model.

Conclusion

Our findings confirm STIM1 as a rational therapeutic target in human glioblastoma, and also indicate that lentivirus-mediated STIM1 silencing is a promising therapeutic strategy for human glioblastoma.     

BMP4在胶质母细胞瘤的多药耐药中的作用及机制研究

背景与目的：近年来的一系列实验证实,骨形成发生蛋白4（bone morphogenetic proteins 4,BMP41在体内外可以抑制肿瘤的生长,但其机制还不清楚。本研究旨在探讨BMP4在胶质母细胞瘤多药耐药中的作用及机制。方法：检测人脑胶质母细胞瘤和正常脑组织标本中BMPd的表达量：构建多药耐药细胞株并进行鉴定．检测在多药耐药细胞株和正常胶质母细胞瘤细胞株内BMP4的表达量：通过在多药耐药细胞株中高表达BMP4．检测BMP4逆转多药耐药的可能性：通过检测高表达BMP4后耐药相关基因的表达变化．初步筛选出BMPd调节胶质母细胞瘤多药耐药的可能机制。结果：在胶质母细胞瘤内,BMP4表达量降低：多药耐药细胞株构建成功．且与对照组相比,多药耐药细胞株的BMP4表达量明显降低,高表达BMP4可以逆转多药耐药：高表达BMP4后,多药耐药相关的基因中,BCL-2和GDNF表达量明显降低。结论：BMP4可以逆转胶质母细胞瘤多药耐药．其可能机制是通过调节BCL-2和GDNF的表达．     

Inhibition of basigin expression in glioblastoma cell line via antisense RNA reduces tumor cell invasion and angiogenesis

Basigin/CD147, also named extracelluar matrix metalloproteinase inducer (EMMPRIN), has been implicated in playing very important roles in several aspects of tumor progression. In this study, we examined the inhibitory effects of antisense RNA of CD147 on invasion and angiogenesis of human glioblastoma U251 cells in vitro. The U251 cell line was transfected by a plasmid containing antisense CD147 cDNA. Gelatin zymography was used to determine the effect on reducing secretions of MMP-2 and MMP-9 of the transfected cells. Boyden chamber was employed to test the invasion of U251 cells in vitro. We found that downregulation of CD147 resulted in reducing secretions of MMP-2, MMP-9, and VEGF. Moreover, the invasion of stable antisense transfectants was inhibited. Wound-induced migration assay also showed decreased migration in stable antisense transfectants compare to parental- and empty vector-transfected cells. Taken together, these results provide evidence that invasion of human glioblastoma cells can be inhibited by antisense RNA of CD147. Basigin/CD147 may be used as a potential target of drugs for anti-invasion and metastasis of human glioblastoma cells.     

Histone deacetylase inhibitors such as sodium butyrate and trichostatin A inhibit vascular endothelial growth factor (VEGF) secretion from human glioblastoma cells

We investigated the effects of histone deacetylase (HDAC) inhibitors such as sodium butyrate (SB) and trichostatin A (TSA) on the expression of vascular endothelial growth factor (VEGF) by human glioblastoma T98G, U251MG, and U87MG cells. The glioblastoma cells secreted three VEGF isoforms, VEGF (189), (165), and (121), although the expression levels of VEGF differed between the cell types. Treatment with either 5mM SB or 100ng/ml TSA reduced VEGF secretion in conditioned media and reduced VEGF mRNA expression. We also studied the expression of VEGF-B,-C, and-D mRNA in human glioblastoma cells and their modulation by HDAC inhibitors. The PCR products of VEGF-B (357 bp), VEGF-C (501 bp), and VEGF-D (484 bp) were amplified in all glioblastoma cells examined. Treatment with SB reduced the expression of VEGF-D mRNA in U251MG cells and the expression of VEGF-B mRNA in U87MG cells. TSA treatment reduced the expression of VEGF-D in U251MG cells. These results suggest that HDAC inhibitors reduce VEGF secretion and modulate the expression of the other VEGF family members, and therefore may inhibit angiogenesis in glioblastoma tissues.     

Influence of the MACC1 Gene on Sensitivity to Chemotherapy in Human U251 Glioblastoma Cells

Background: This study was conducted to determine the influence of MACC1 expression on chemotherapysensitivity in human U251 glioblastoma cells. Materials and Methods: Expression of the MACC1 gene in 49 casesof human brain glioma was determined by quantitative real-time PCR. Silencing effects of RNA interference onMACC1 was detected by Western-blotting. Flow cytometry methods and methyl thiazolyl tetrazolium assay (MTT)were used to determine the apoptosis and growth inhibitory rates of the U251 cells with MACC1 silencing. beforeand after treatment with cisplatin (DDP). Results: MACC1 mRNA in gliomas was up-regulated remarkably, to158.8% of that in peri-cancerous tissues (P<0.05). The siRNA-MACC1 could inhibit the expression of MACC1protein significantly (p<0.05), associated with an increase in apoptosis rate from 2.57% to 5.39% in U251 cellsand elevation of the growth inhibitory rate from 1.5% to 17.8% (p<0.05 for both). After treatment with DDP atvarious concentrations (1, 3, 5μg/ml), compared with control U251 cells, the apoptosis rate of MACC1-silencedU251 cells rose from 8.41%, 13.2% and 19.5% to 12.8%, 17.8% and 25.8%; the growth inhibitory rate increasedfrom 16.2%, 19.3% and 24.5% to 23.7%, 28.4% and 36.3%. Conclusions: There is a notable relationship betweenover-expression of MACC1 and the characteristics of glioma cells. Silencing of MACC1 was found to enhancethe apoptosis and growth inhibitory rates of U251 glioma cells, and thereby increase their sensitivity to DDPchemotherapy.