缺氧条件下全反式维甲酸对U87胶质瘤细胞血管内皮生长因子表达的影响

目的研究模拟缺氧条件下全反式维甲酸(ATRA)对U87胶质瘤细胞血管内皮生长因子(VEGF)表达的影响及其可能的机制。方法 U87胶质瘤细胞分为空白对照组、缺氧对照组、低浓度干预组、高浓度干预组。CoCl2模拟缺氧,U87胶质瘤细胞经不同浓度ATRA(5、10μmol/L)干预后,实时定量PCR法及Western blot法分别检测细胞中VEGF mRNA、缺氧诱导因子1α(HIF-1α)mRNA及VEGF蛋白的表达。结果与缺氧对照组相比,低、高浓度干预组VEGF mRNA表达分别为缺氧对照组的(2.08±0.23)倍及(3.13±0.14)倍,两组与缺氧对照组的差异均具有统计学意义(均P<0.01);低、高浓度干预组HIF-1αmRNA表达分别为缺氧对照组的(1.62±0.07)倍及(1.83±0.09)倍,两组与缺氧对照组的差异均具有统计学意义(均P<0.01)。而VEGF蛋白相对表达量在缺氧对照组为(2.15±0.12),低浓度干预组为(2.32±0.20),高浓度干预组为(3.09±0.08),各组间差异均具有统计学意义(均P<0.05)。结论在模拟缺氧条件下,ATRA可在转录及翻译水平增加U87细胞中VEGF的表达,而这种表达上调可能部分通过上调HIF-1α表达实现。     

92例高级别胶质瘤患者术后生存分析

目的探讨影响高级别胶质瘤术后生存的因素。方法对2014年1月至2016年8月首诊确定为高级别胶质瘤(WHO III-IV级)的92例患者采用Kaplan-Meier法分析生存率,Log-rank检验进行单因素分析,Cox回归模型进行多因素分析。结果中位生存期为15个月,中位无进展生存期为8个月,肿瘤全切率为72. 83%,1年、2年、3年、4年的生存率分别为56. 5%,35. 9%,30. 4%,25. 4%。Log-rank单因素分析表明高级别胶质瘤预后与年龄、术前生活质量评分、肿瘤大小、数目、是否累及多个皮层脑叶或者运动功能区、切除程度、病理级别、异柠檬酸脱氢酶基因是否突变、O-6-甲基鸟嘌呤DNA甲基转移酶基因启动子是否甲基化、Ki 67指数、术后是否进行放疗和/或化疗以及所进行的放化疗的方式、复发后是否积极治疗相关(P 0. 05)。引入检验水准(α=0. 01),COX多因素分析表明年龄、肿瘤切除程度、术后是否进行放疗和/或化疗是影响高级别胶质瘤预后的独立危险因素(P 0. 01)。结论发病年龄65岁、肿瘤全切除、术后进行同步放化疗和辅助化疗的高级别胶质瘤患者预后较好。     

Allergy and risk of glioma: a meta‐analysis

We evaluated the association between allergic conditions and the risk of glioma in case–control and cohort studies published so far on this issue. A total of 12 studies (10 case–control and 2 cohort studies) were included in the analysis, involving 61 090 participants, of whom 6408 had glioma. When compared with non‐allergic conditions, the pooled odds ratio (OR) with any allergic conditions for glioma was 0.60 (95% CI: 0.52–0.69, P < 0.001), suggesting a significant negative association (protective effect) between allergy and glioma. Subgroup analysis showed that the ORs were 0.70 (95% CI: 0.62–0.79, P < 0.001), 0.69 (95% CI: 0.62–0.78, P < 0.001), and 0.78 (95% CI: 0.70–0.87, P < 0.001) for asthma, eczema, and hay fever, respectively. The significant association remained even after excluding the bias of proxy reporting (OR = 0.61; 95% CI: 0.50–0.75, P < 0.001). We conclude that allergic conditions may significantly reduce the risk of glioma.     

Antisense epidermal growth factor receptor RNA transfection in human malignant glioma cells leads to inhibition of proliferation and induction of differentiation

The epidermal growth factor receptor (EGFR) is a proto-oncogene that is frequently observed with alterations in late stage gliomas, suggesting an important role of this gene in glial tumorigenesis and progression. In this study we evaluated an antisense EGFR approach as an alternative therapeutic modality for glioblastomas. We transfected U-87MG cells with an antisense EGFR construct and obtained several clones stably expressing lower or undetectable levels of EGFR protein. These clones were found to have impaired proliferation as well as a reduced transforming potential to grow in soft agarose. The number of cells positive for the cell cycle-specific nuclear antigen Ki-67 was also significantly decreased ( P <0.05) in antisense EGFR-transfected clones compared with parental or empty vector-transfected cells. Flow cytometric analysis revealed that the proportion of cells in G₀ /G₁ phases of the cell cycle in the antisense clones increased by up to 31% compared with control cells, whereas the proportion of cells in S phase decreased by up to 58%. In addition, the antisense EGFR-transfected cells showed higher expression of glial fibrillary acidic protein and a more differentiated form, with smaller cell bodies possessing fine tapering cell processes. These results suggest that EGFR plays a major role in modulating cell growth and differentiation in glioblastoma cells. Our experimental model of antisense EGFR provides a basis for future development of antisense EGFR oligodeoxynucleotides in treatment of glioblastomas.     

基于靶向低密度脂蛋白受体蛋白1的载药嵌段共聚物抗胶质瘤作用的体外实验研究

目的研究靶向低密度脂蛋白受体蛋白1(LRP1)的载药嵌段共聚物(ANPs/CPT)对胶质瘤细胞的增殖抑制和促进凋亡的作用。方法采用Western blotting技术检测LRP1在大鼠胶质瘤细胞(C6细胞)和脑毛细血管内皮细胞(BCECs)的表达水平。用激光共聚焦显微镜测定C6细胞和BCECs对Angiopep-2修饰的靶向未载药嵌段共聚物(ANPs)和非靶向对照NPs的摄取量;采用噻唑蓝(MTT)比色法检测ANPs/CPT抑制C6细胞和BCECs增殖的作用;采用流式细胞仪分析不同CPT终浓度(10μg/mL,20μg/mL)的ANPs/CPT促C6细胞凋亡作用。结果 LRP1在C6和BCECs细胞膜表面高表达。C6细胞对ANPs的摄取量显著高于NPs(P<0.01);ANPs/CPT对C6细胞的增殖抑制作用显著高于NPs/CPT(P<0.05),但对BCECs的增殖抑制作用与NPs/CPT无显著差异(P> 0.05)。CPT终浓度10μg/mL、20μg/mL的ANPs/CPT与NPs/CPT作用于C6细胞48 h后的凋亡率分别为(16.1±0.9)%、(30.4±...     

RNA interference affects tumorigenicity and expression of insulin-like growth factor-1, insulin-like growth factor-1 receptor, and basic fibroblast growth factor-2 in rat C6 glioma cells

BACKGROUND： Human gliomas are more likely to express basic fibroblast growth factor-2 （FGF-2） insulin-like growth factor-1（IGF-1）, and IGF-1 receptor （IGF-1R） than normal brain tissue. These factors activate signal transduction systems of Ras/MAPK and PI3K/Akl, which promote glioma growth. OBJECTIVE： To utilize RNA interference （RNAi） technique to down-regulate FGF-2, IGF-1, and IGF-1R gene expression, and to investigate the effects of these genes on rat C6 glioma cells, as well as the feasibility of RNAi for treating glioma. DESIGN, TIME AND SETTING： This neurooncological, randomized, controlled, in vivo and in vitro experiment, which used RNAi methodology, was performed at the Laboratory of Molecular Biology, Institute of Biochemistry, Chinese Academy of Sciences between August 2005 and February 2008. MATERIALS： Rat C6 cell lines were purchased from Shanghai Institute of Cellular Biology Affiliated to Chinese Academy of Sciences. Small interfering RNA （siRNA） was synthesized by Shanghai GenePharma. Anti-IGF-1, anti-IGF-1R, anti-FGF-2, anti-mouse and anti-rabbit IgG G1-HRP antibodies were provided by Santa Cruz Biotechnology, USA. Four to six week-old BALB/c nude mice were purchased from the Laboratory Animal Center, Chinese Academy of Sciences. METHODS： C6 glioma cells were transfected with siRNA, which was chemically synthesized in vitro to correspond to endogenous FGF-2, IGF-1, and IGF-1R genes. The inhibition ratio of targeting mRNA expression was detected by semiquantitative RT-PCR, and protein expression was determined by Western blot analysis. C6 glioma cell proliferation was observed using a growth curve C6 glioma cell apoptosis rate and cell cycle were detected by flow cytometry. C6 glioma cell growth regression was observed by transwell migration assay. In addition, nude mouse subcutaneous tumor models were used in this study. For studying the anti-tumor effects of IGF-1 and IGF-1R siRNA, two blank control groups, with six mice each, were set up： A （2.5 μg siRNA was injected one week after C6 cells were inoculated, Le., when tumor volume reached 8 mm × 8 mm） and B （siRNA was injected at the same time with C6 cells were inoculated. To study the effects of FGF-2 siRNA, the groups consisted of a blank control group, negative control group, 2.6 μg siRNA group, 4 μg siRNA group, and 5.3 μg siRNA group, with six mice each. MAIN OUTCOME MEASURES： mRNA and protein inhibition ratio of FGF-2, IGF-1, and IGF-1 R; C6 glioma cell proliferation, apoptosis, and cycle growth arrest; C6 glioma cell growth regression and subcutaneous tumorigenicity rates. RESULTS： All siRNA constructs proved to be effective. After 48 hours, transfection of 200 nmol/L siRNA resulted in a FGF-2 or IGF-1R gene inhibition ratio 〉 80% and an IGF-1 gene inhibition ratio of approximately 70%. Protein expression levels for FGF-2, IGF-1, and IGF-1R decreased in a dose-dependent manner following siRNA transfection, with an inhibition rate 〉 85%, 60%, and 50%, respectively. C6 glioma cell proliferation and apoptosis rates increased in proportion to siRNA. The apoptosis rate of C6 glioma cells induced by FGF-2, IGF-1, and IGF-1R siRNA was 39.96%, 15.07% and 22.47%, respectively （P 〈 0.01）. Transfection of 200 nmol/L IGF or IGF-1R siRNA for 48 hours suppressed C6 glioma cell migration. At 30 days after intratumoral injection of 2.6, 4, and 5.3 tJg FGF-2 siRNA, tumor growth regression rate of FGF-2 siRNA was 56%, 67%, and 86%, respectively. The tumor growth regression rate was 71.88% and 45.71%, respectively, when IGF-1 or IGF-1R siRNA was intratumorally injected 1 week after C6 glioma cell transplantation. When IGF-1 or IGF-1 R siRNA was intratumorally injected during C6 glioma cell transplantation, the tumor growth regression rate was 78.13% and 74.29%, respectively. CONCLUSION： siRNA transfection downregulated gene expression of FGF-2, IGF-1, and IGF-1R In addition, siRNA treatment markedly suppressed glioma cell proliferation, growth, and migration, and concomitantly reduced subcutaneous tumorigenicity.     

Endocannabinoid system in the adult rat circumventricular areas: An immunohistochemical study

Endocannabinoids (ECs) are important neuromodulators involved in a plethora of physiological processes such as modulation of synaptic transmission, neuroprotection, immune function, and neurodevelopment, among others. However, still lacking is a detailed study on the presence of this system in the circumventricular areas, brain structures controlling the interaction between cerebrospinal fluid and brain parenchyma. The aim of this work was to provide the anatomical basis supporting a functional role of ECs in the activity of circumventricular areas. To this end, an immunohistochemical study of the EC system in rat brain was performed. Receptors and synthesizing and degrading enzymes for ECs were widely distributed in rat ependyma and subependyma, marginal glia, and circumventricular organs (CVOs) such as the choroid plexus, subfornical organ, subcommissural organ, median eminence, and area postrema. These zones constitute barrier systems between the brain parenchyma and the ventricular or subarachnoid cerebrospinal fluid (CSF) and between the extracellular hemal milieu of CVOs and the brain parenchyma or the CSF. By immunohistochemistry and real‐time polymerase chain reaction we found DAGLα, DAGLβ, NAPE‐PLD, MAGL, and FAAH in the ependyma. These finding suggest that the ependyma can release and clear ECs from the ventricular CSF. Subependymal astrocytes and tanycytes displayed DAGLα immunoreactivity but parenchymal astrocytes did not express EC‐synthesizing enzymes, thus establishing a sharp distinction between these two astrocyte populations. CB1 was located in fibers innervating discrete subventricular zones such as the neurogenic striatal subventricular zone and the fourth ventricle. CB1 fibers also innervated some CVOs. J. Comp. Neurol. 518:3065–3085, 2010. © 2010 Wiley‐Liss, Inc.     

金属蛋白酶2、血管内皮生长因子和肿瘤抑制因子在人脑胶质瘤中的表达和临床意义

目的:探讨人脑胶质瘤中的金属蛋白酶2(MMP-2)、血管内皮生长因子(VEGF)和肿瘤抑制因子(P16)的表达。方法:应用免疫组化法检测55例胶质瘤组织中的MMP-2、VEGF和P16蛋白的表达,通过原位杂交检测MMP-2 mRNA的表达。结果:胶质瘤的恶性程度与MMP-2、VEGF表达和P16的缺失表达呈正相关,随着胶质瘤的恶性程度的增高而增加。结论:胶质瘤的恶性程度由多种因素决定。胶质瘤中MMP-2含量越高,肿瘤细胞在浸润的过程中突破血脑屏障的能力越强;VEGF的表达增加,肿瘤的血液供应越丰富,恶性程度越高。P16蛋白缺失率高,组织学分化程度低,在一定程度上反映了胶质瘤细胞的恶性生物学行为。     

CXCR4活化促进人恶性胶质瘤细胞分泌血管生成因子

目的观测CXCR4活化对人恶性胶质瘤细胞系U87中血管内皮生长因子（VEGF）、白细胞介素-8（IL-8）基因表达及蛋白分泌的影响。方法采用间接免疫荧光标记观测CXCR4在U87细胞中的表达和定位；用间质细胞衍生因子-1α（SDF-1α）激活CXCR4，通过酶联免疫吸附试验（ELISA）检测U87细胞培养上清中VEGF、IL-8蛋白的含量，用逆转录聚合酶链反应（RT-PCR）检测二者mRNA的表达。结果CXCR4表达于U87细胞的胞膜和胞质，经活化后可增加VEGF、IL-8mRNA的表达和蛋白分泌量。结论人恶性胶质瘤细胞中CXCR4活化后能够促进血管生成因子VEGF和IL-8的产生。     

LRIG1、EGFR、E-Cadherin及N-Cadherin在胶质瘤中表达及其临床意义

目的研究富含亮氨酸重复序列免疫球蛋白样蛋白1(LRIG1)、表皮生长因子受体(EGFR)、ECadherin及N-Cadherin在不同病理级别胶质瘤中表达差异,探讨LRIG1在胶质瘤恶性进展中可能的作用机制。方法收集74例胶质瘤患者手术标本,包含12对原发及复发配对胶质瘤标本,采用qRT-PCR检测LRIG1、EGFR、E-Cadherin、N-Cadherin基因的表达,并采用免疫印迹检测LRIG1、EGFR、E-Cadherin、NCadherin、Vimentin蛋白表达情况。结果随着胶质瘤病理级别的升高,LRIG1、E-Cadherin基因及蛋白表达水平降低,EGFR、N-Cadherin基因及蛋白表达水平升高,差异均具有统计学意义(均P0.05)。WHOⅢ-Ⅳ组胶质瘤EGFR/LRIG1及N-Cadherin/E-Cadherin比值显著高于WHOⅠ-Ⅱ组(均P0.05)。EGFR/LRIG1与NCadherin/E-Cadherin变化之间存在正相关(r=0.56,P0.05)。对原发及复发配对胶质瘤标本的研究结果与上述一致。结论胶质瘤中EGFR/LRIG1表达失衡,可能通过诱导上皮间质转化(EMT)促进胶质瘤细胞的恶性进展。LRIG1可能成为胶质瘤治疗的新靶点。     

Early expressions of hypoxia-inducible factor 1alpha and vascular endothelial growth factor increase the neuronal plasticity of activated endogenous neural stem cells after focal cerebral ischemia

Endogenous neural stem cells become "activated" after neuronal injury, but the activation sequence and fate of endogenous neural stem cells in focal cerebral ischemia model are little known. We evaluated the relationships between neural stem cells and hypoxia-inducible factor-1α and vascular endothelial growth factor expression in a photothromobotic rat stroke model using immunohistochemistry and western blot analysis. We also evaluated the chronological changes of neural stem cells by 5-bromo-2′-deoxyuridine(BrdU) incorporation. Hypoxia-inducible factor-1α expression was initially increased from 1 hour after ischemic injury, followed by vascular endothelial growth factor expression. Hypoxia-inducible factor-1α immunoreactivity was detected in the ipsilateral cortical neurons of the infarct core and peri-infarct area. Vascular endothelial growth factor immunoreactivity was detected in bilateral cortex, but ipsilateral cortex staining intensity and numbers were greater than the contralateral cortex. Vascular endothelial growth factor immunoreactive cells were easily found along the peri-infarct area 12 hours after focal cerebral ischemia. The expression of nestin increased throughout the microvasculature in the ischemic core and the peri-infarct area in all experimental rats after 24 hours of ischemic injury. Nestin immunoreactivity increased in the subventricular zone during 12 hours to 3 days, and prominently increased in the ipsilateral cortex between 3–7 days. Nestin-labeled cells showed dual differentiation with microvessels near the infarct core and reactive astrocytes in the peri-infarct area. BrdU-labeled cells were increased gradually from day 1 in the ipsilateral subventricular zone and cortex, and numerous BrdU-labeled cells were observed in the peri-infarct area and non-lesioned cortex at 3 days. BrdU-labeled cells rather than neurons, were mainly co-labeled with nestin and GFAP. Early expressions of hypoxia-inducible factor-1α and vascular endothelial growth factor after ischemia made up the microenvironment to increase the neuronal plasticity of activated endogenous neural stem cells. Moreover, neural precursor cells after large-scale cortical injury could be recruited from the cortex nearby infarct core and subventricular zone.     

Down-regulation of caveolin-1 in glioma vasculature: modulation by radiotherapy

Primary brain tumors, particularly glioblastomas (GB), remain a challenge for oncology. An element of the malignant brain tumors' aggressive behavior is the fact that GB are among the most densely vascularized tumors. To determine some of the molecular regulations occuring at the brain tumor endothelium level during tumoral progression would be an asset in understanding brain tumor biology. Caveolin-1 is an essential structural constituent of caveolae that has been implicated in mitogenic signaling, oncogenesis, and angiogenesis. In this work we investigated regulation of caveolin-1 expression in brain endothelial cells (ECs) under angiogenic conditions. In vitro, brain EC caveolin-1 is down-regulated by angiogenic factors treament and by hypoxia. Coculture of brain ECs with tumoral cells induced a similar down-regulation. In addition, activation of the p42/44 MAP kinase is demonstrated. By using an in vivo brain tumor model, we purified ECs from gliomas as well as from normal brain to investigate possible regulation of caveolin-1 expression in tumoral brain vasculature. We show that caveolin-1 expression is strikingly down-regulated in glioma ECs, whereas an increase of phosphorylated caveolin-1 is observed. Whole-brain radiation treatment, a classical way in which GB is currently being treated, resulted in increased caveolin-1 expression in tumor isolated ECs. The level of tumor cells spreading around newly formed blood vessels was also elevated. The regulation of caveolin-1 expression in tumoral ECs may reflect the tumoral vasculature state and correlates with angiogenesis kinetics.     

Soluble VEGFR1 (sVEGFR1) as a novel marker of amyotrophic lateral sclerosis (ALS) in the North Indian ALS patients

Background and purpose: North Indian patients with amyotrophic lateral sclerosis (ALS) exhibit substantially extended survival time after onset of the disease as compared to their Western counterparts. Earlier, we found that vascular endothelial growth factor‐A (VEGF‐A) may be associated with increased survival of these patients. We now measured soluble vascular endothelial growth factor receptor‐1 (sVEGFR1), an inhibitor receptor for VEGF‐A, in these patients with ALS. Methods: Patients with sporadic ALS (n = 36) attending the Neurology Outpatient at Post Graduate Institute of Medical Education and Research (PGIMER) at Chandigarh were included on the basis of El Escorial criteria. The sVEGFR1 levels were analyzed in serum of these patients using enzyme‐linked immunosorbent assay (ELISA) and compared with normal controls (n = 36). Results: Soluble vascular endothelial growth factor receptor‐1 was found to be decreased significantly in serum of patients with ALS. Serum obtained from definite ALS revealed significantly lower sVEGFR1 as compared to probable ALS. However, there was no difference in serum sVEGFR1 levels between male and female patients with ALS. Conclusions: Soluble vascular endothelial growth factor receptor‐1 downregulation may result in increased serum VEGF‐A reported previously in our patients with ALS and may indicate the activation of compensatory mechanism in response to neurodegeneration. The lower serum sVEGFR1 levels may have a possible clinicopathological association, if not causal, to the extended survival of North Indian patients with ALS; however, the result needs further investigations particularly in comparable Caucasian ALS population.     

MPTP小鼠脑沉默信息调节因子1和缺氧诱导因子-1α的表达及行为学检测

目的本研究旨在研究MPTP模型小鼠中沉默信息调节因子1(SIRT1)和缺氧诱导因子1α(HIF-1α)的表达情况以及行为学的变化。方法选用MPTP处理C57BL/6小鼠构建PD动物模型,采用行为学实验、高效液相色谱(HPLC)、免疫组化等方法检验模型的建立是否成功,并在小鼠模型中检测SIRT1和HIF-1α的表达情况。结果 MPTP处理的小鼠表现出显著的行为学异常,主要体现在自主活动减少(P0.001)、步距缩短(P0.001),且有显著运动迟缓(P0.001)。HPLC结果发现,模型组小鼠纹状体区域多巴胺(DA)及其代谢产物减少(P0.001)。免疫组化结果提示黑质区域多巴胺能神经元标志物酪氨酸羟化酶(TH)和多巴胺转运体(DAT)的表达明显下调(P0.01)。分子生物学方面,PD模型小鼠的SIRT1表达降低(P0.05),HIF-1α表达增加(P0.05)。结论 PD模型小鼠表现出明显的行为学异常,多巴胺能神经元标志物检测提示成功复制PD动物模型,同时发现模型小鼠的SIRT1/HIF-1α的表达异常,提示该信号通路可能参与了PD的疾病过程。     

全反式维甲酸对胶质瘤干细胞VEGF和bFGF表达的影响

目的 研究全反式维甲酸(ATRA)对胶质瘤干细胞(GSCs)血管内皮细胞生长因子(VEGF)和碱性成纤维细胞生长因子(bFGF)表达的影响. 方法 从人胶质母细胞瘤细胞系U87中分离培养GSCs,免疫荧光染色检测CD133、巢蛋白(nestin)的表达进行鉴定.将取GSCs分成3组分别培养:(1)ATRA组:培养基中含10 nmol/L ATRA;(2)空载体组:培养基中含与ATRA组等量的二甲基亚砜(DMSO);(3)对照组:单纯培养基,培养10 d后免疫荧光染色检测胶质纤维酸性蛋白(GFAP)、β-微管蛋白Ⅲ(β-tubulinⅢ)、半乳糖脑苷脂(GalC)的表达;CCK8法检测各组细胞的增殖;ELISA和RT-PCR分别检测各组GSCs VEGF、bFGF的分泌水平和mRNA的表达. 结果 二代细胞球表达神经干细胞(NSCs)的标记抗体CD133和nestin.免疫荧光染色检测显示分化后GSCs能够分化为多种同源子代细胞(分别表达星形胶质细胞、神经元、少突胶质细胞标志物GFAP、β-tubulinⅢ、Galc);培养10d后ATRA组细胞GFAP的阳性表达率高于对照组及空载体组,差异有统计学意义(P＜0.05).第3.～7天ATRA组细胞增殖速度较对照组和空载体组明显变缓,差异有统计学意义(P＜0.05);分化24 h后ATRA组GSCs VEGF、bFGF的分泌水平和mRNA的表达均少于对照组和空载体组,差异有统计学意义(P＜0.05). 结论 ATRA能诱导GSCs分化并抑制其增殖,其可能通过抑制VEGF和bFGF的表达发挥抗胶质母细胞瘤的作用.     

Transient axonal glycoprotein-1 induces apoptosis- related gene expression without triggering apoptosis in U251 glioma cells

Previous studies show that transient axonal glycoprotein-1, a ligand of amyloid precursor pro- tein, increases the secretion of amyloid precursor protein intracellular domain and is involved in apoptosis in Alzheimer＇s disease. In this study, we examined the effects of transient axonal glyco- protein-1 on U251 glioma cells. 3-（4,5-Dimethylthiazol-2-yl）-2,5-diphenyltetrazolium bromide assay showed that transient axonal glycoprotein-1 did not inhibit the proliferation of U251 cells, but promoted cell viability. The terminal deoxynucleotidyl transferase dUTP nick end labeling assay showed that transient axonal glycoprotein-1 did not induce U251 cell apoptosis. Real-time PCR revealed that transient axonal glycoprotein-1 substantially upregulated levels of amyloid precursor protein intracellular C-terminal domain, and p53 and epidermal growth factor recep- tor mRNA expression. Thus, transient axonal glycoprotein-1 increased apoptosis-related gene expression in U251 cells without inducing apoptosis. Instead, transient axonal glycoprotein-1 promoted the proliferation of these glioma cells.