B7-H1 is correlated with malignancy-grade gliomas but is not expressed exclusively on tumor stem-like cells

Human glioblastoma is well known for its capacity to interfere with effective antitumor immune responses. B7-H1 is the third member of the B7 family that plays important roles in tumor immune evasion. Recent studies have shown that brain tumor stem-like cells (TSCs) contribute to tumorigenesis and radioresistance. However, the relationship between B7-H1 and the clinical behavior of brain TSCs remains unclear. In the present study, we report that B7-H1 is correlated with the malignancy grade of astrocyte tumors. B7-H1 was significantly upregulated at the growing edge of the tumors. Immunostaining and flow cytometric analysis indicate that B7-H1 was expressed primarily by Ki67-negative tumor cells. In vitro, tumors cultured under medium favoring the growth of neural stem cells were able to form spheres, along with expression of neural stem/progenitor cell markers. These cells were able to differentiate into different neural lineages when cultured in differentiation medium, indicating that these cells have TSC characteristics. We also found that B7-H1 was expressed, but not exclusively on CD133-positive stem cells. Interestingly, we found that CD133-negative tumor cells also had the capacity to form brain tumors. Our data establish a correlation between the expression of the negative costimulatory molecule B7-H1 and the malignancy grade of human gliomas, suggesting that B7-H1 may be a novel tumor marker and target for therapy, although it is not expressed exclusively on brain TSCs.     

应用长春新碱分离与鉴定U87细胞系中的胶质瘤干细胞

背景与目的:研究表明,肿瘤干细胞具有化疗抵抗性.本研究拟利用肿瘤干细胞对化疗药物耐受的特性,在培养基中添加长春新碱的方法从人胶质瘤细胞系U87中分离鉴定肿瘤干细胞.方法:U87细胞于含血清培养基中贴壁后,换用含有5 ng/ml长春新碱的神经干细胞培养基培养,获得第一代肿瘤细胞球后,将单细胞接种于神经干细胞培养基中,获得第二代肿瘤细胞球.免疫荧光检测巢蛋白(nestin)、胶质纤维酸性蛋白(glial fibrillary acidic protein,GFAP)、β-微管蛋白Ⅲ(β-tubulin Ⅲ)、髓鞘碱性蛋白(myelin basic protein,MBP)在第二代肿瘤细胞球及其分化细胞中的表达.结果:成功地获得了第一代肿瘤细胞球以及来源于单细胞的第二代肿瘤细胞球;细胞间紧密相贴,表面较光滑;神经干细胞标志物nestin在第二代肿瘤细胞球中呈阳性表达;第二代肿瘤细胞球分化细胞中可检测到nestin、GFAP、β-tubulin Ⅲ、MBP的表达.结论:U87细胞系中存在具有自我更新及多向分化能力的胶质瘤干细胞,采用神经干细胞培养基中添加长春新碱的方法能简单有效地从胶质瘤细胞系中分离培养出胶质瘤干细胞.     

B7-H4 is preferentially expressed in non-dividing brain tumor cells and in a subset of brain tumor stem-like cells

B7-H4, a newly discovered member of B7 family that negatively regulates T cell-mediated immunity, may facilitate tumor progression by undermining host immunity. Recent studies show that brain tumor stem-like cells (TSCs) contribute to tumorigenesis. However, the relationship between B7-H4 and the clinical behavior of brain TSCs remains unclear. In this study, we found that B7-H4 was expressed in cultured tumor cells from human gliomas (n = 5) and medulloblastomas (n = 3). Double immunostaining indicated that B7-H4 was primarily restricted to non-dividing (Ki67(-)) cultured tumor cells. Tumor cells cultured under medium conditions favoring the growth of neural stem cells were able to form primary and secondary spheres, along with expression of neural stem/progenitor cell markers. These cells differentiated into different neural lineages when cultured in differentiation medium, indicating that these cells have TSCs characteristics. Double immunostaining showed that TSCs consisted of proliferative (Ki67(+)) and quiescent (Ki67(-)) cells. We also found that B7-H4 was expressed in a small population of CD133(+) cells sorted by flow cytometry. Interestingly, both CD133(+) and CD133(-) cells were tumorigenic in SCID mice in vivo. However, CD133(+) cells-initiated glioblastomas showed a higher proliferation index, compared to CD133(-) cells-induced glioblastomas in vivo. Secondary glioma cells derived from CD133(+) or CD133(-) cell xenografts expressed B7-H4 as well. Our data suggest B7-H4 is preferentially expressed in non-dividing brain tumor cells and in a subpopulation of brain TSCs, and CD133(-) tumor cells also have the capacity to initiate brain formation in vivo.     

塞来昔布对胶质瘤U251细胞增殖、凋亡和Survivin表达的影响

背景与目的:选择性COX-2抑制剂塞来昔布是近年来开发的新型非甾体类抗炎药。大量实验证明塞来昔布具有明显的抑制肿瘤细胞增殖和诱导凋亡的作用,这在结直肠肿瘤和家族性腺瘤性息肉病中已经得到了证实。本研究观察塞来昔布在体外对人胶质瘤细胞株U251的抑制增殖和诱导凋亡的作用,并探讨该作用与Survivin表达之间的关系。方法:用不同浓度塞来昔布溶液处理对数生长期的U251细胞,在倒置显微镜下动态观察瘤细胞的生长情况。用MTT比色法检测不同时间点各药物浓度组细胞增殖情况。不同浓度塞来昔布处理U251细胞48h后,用流式细胞技术检测各组细胞的凋亡率,免疫细胞化学法及Westernblot法检测各组细胞中Survivin蛋白的表达情况,逆转录聚合酶链反应(RT-PCR)半定量法检测各组细胞中survivinmRNA的表达水平。结果:塞来昔布处理后细胞出现明显凋亡样形态学改变。10~100μmol/L塞来昔布对U251细胞增殖均有抑制作用,该作用随着药物浓度的增加和作用时间的延长而增强。塞来昔布处理U251细胞48h后,流式细胞检测结果显示出明显的细胞凋亡,凋亡率随着塞来昔布浓度的增高而升高;免疫细胞化学结果显示,对照组细胞...     

FUBP1基因在脑胶质瘤中的表达及其对U251细胞凋亡的影响

目的：研究FUBP1基因在脑胶质瘤中的表达及其对胶质瘤U251细胞凋亡的影响。方法：Real-time PCR检测35例脑胶质瘤及相应癌旁组织中FUBP1 mRNA的表达。设计并合成FUBP1基因特异性的siRNA,转染U251细胞。转染后,western blot检测转染后FUBP1蛋白的表达,双标流式细胞法检测细胞凋亡率。结果：与癌旁组织相比,FUBP1 mRNA在脑胶质瘤组织中表达明显上调。转染后,U251细胞中的FUBP1蛋白表达明显降低,同时,凋亡率明显增加。结论：FUBP1基因在脑胶质瘤中存在表达异常,其表达降低能够促进细胞凋亡。     

胶质瘤干细胞、肿瘤相关巨噬细胞和B7-H1在脑胶质瘤组织中的表达及其意义

目的:探讨胶质瘤干细胞（glioma stem cells,GSCs）、肿瘤相关巨噬细胞（tumor-associated macrophages,TAMs）和负性共刺激分子B7-H1(B7 homolog 1)在不同病理级别脑胶质瘤组织中的表达及其相关性。方法:对30例低级别脑胶质瘤（WHOⅠ级、Ⅱ级）和30例高级别脑胶质瘤（WHOⅢ级、Ⅳ级）标本做连续石蜡包埋切片,用免疫组化SP法检测各组标本中GSCs、TAMs和B7-H1的表达情况,采用CD133作为GSCs的标志物,以CD68作为TAMs的标志物。用Image-Pro Plus 6.0软件分析每个视野阳性染色的积分光密度（IOD）,每个组织切片在400倍镜下分析20个视野。结果:CD133、CD68和B7-H1在高级别脑胶质瘤组织中的表达水平明显高于低级别脑胶质瘤组织（P＜0.01、P＜0.01、P＜0.01）;脑胶质瘤组织中B7-H1的空间表达位置在CD68+TAMs的分布区域较强;CD133与CD68的表达呈正相关（P＜0.001）,CD133与B7-H1的表达呈正相关（P＜0.001）。结论:随着病理级别的增高,脑胶质瘤组织中GSCs、TAMs和B7-H1的表达均增高,并且CD133与CD68和B7-H1的表达呈显著正相关。     

FUBP1基因在脑胶质瘤中的表达及其对U251细胞凋亡的影响

目的:研究FUBP1基因在脑胶质瘤中的表达及其对胶质瘤U251细胞凋亡的影响。方法:Real-time PCR检测35例脑胶质瘤及相应癌旁组织中FUBP1 mRNA的表达。设计并合成FUBP1基因特异性的siRNA,转染U251细胞。转染后,western blot检测转染后FUBP1蛋白的表达,双标流式细胞法检测细胞凋亡率。结果:与癌旁组织相比,FUBP1 mRNA在脑胶质瘤组织中表达明显上调。转染后,U251细胞中的FUBP1蛋白表达明显降低,同时,凋亡率明显增加。结论:FUBP1基因在脑胶质瘤中存在表达异常,其表达降低能够促进细胞凋亡。     

U251源性脑肿瘤干细胞的耐药性及耐药酶的表达

背景与目的：从胶质瘤中分离的肿瘤干细胞（cancer stem cells,CSCs）是胶质瘤的种子细胞和复发的源泉,它们不能被有效的杀死导致胶质瘤的预后不理想。本研究旨在探讨胶质瘤来源的肿瘤干细胞对化疗药物的耐药性及相关耐药酶的表达。方法：用免疫磁珠法从U251细胞中分选肿瘤干细胞（U251-CSC）后继续培养;MTT比色试验法观察化疗药物替尼泊苷（Vm-26）、卡莫司汀（BCNU）和顺铂（DDP）对U251和U251-CSC的增殖抑制作用,流式细胞仪检测3种化疗药物引起的细胞凋亡;Western blot免疫印迹法检测3种耐药酶LRP、MGMT和TopoⅡα的表达。结果：在3种药物作用下,U251的生长抑制比U251-CSC明显,U251的细胞凋亡率高于U251-CSC;U251-CSC表达LRP、MGMT和TopoⅡα的强度高于U251。结论：胶质瘤肿瘤干细胞对化疗药物Vm-26、BCNU和DDP有高耐药性,原因可能是肿瘤干细胞高表达耐药酶LRP、MGMT和TopoⅡα。     

纳米Fe3O4／CD133Ab复合物对胶质瘤U251细胞放疗增敏作用的实验研究

目的 探讨纳米Fe3O4／CD133Ab复合物对脑胶质瘤U251细胞的放射增敏作用。方法 细胞免疫组化法检测脑胶质瘤U251细胞CD133的表达情况;流式细胞分选获得U251-CD133+细胞;MTT法观察纳米Fe3O4／CD133Ab复合物和CD133Ab分别对脑胶质瘤细胞U251及U251-CD133+的细胞毒作用;克隆形成抑制实验检测纳米Fe3O4／CD133Ab复合物和CD133Ab对脑胶质瘤U251细胞放射增敏的影响。结果 脑胶质瘤U251细胞中有CD133分子阳性表达并可以分选出CD133阳性表达细胞;在0.0488～25μg／ml范围内,纳米Fe3O4／CD133Ab复合物作用于脑胶质瘤U251及U251-CD133+细胞24h的细胞毒性呈明显剂量依赖性,与阴性对照组比较,差异有统计学意义（P＞0.05）。纳米Fe3O4／CD133Ab复合物对脑胶质瘤U251和U251-CD133+细胞的增殖抑制率最高值分别为59.46％和56.66％,IC50分别为11.84μg／ml和12.06μg／ml。纳米Fe3O4／CD133Ab复合物+照射组与CD133Ab+照射组比较,细胞存活分数差异有统计学意义（P＜0.05）,在照射4Gy以上时,随X射线剂量增加而放射敏感性增强。结论 纳米Fe3O4／CD133Ab复合物对脑胶质瘤细胞U251和U251-CD133+有细胞毒作用,并且对U251细胞有放射增敏作用。     

肿瘤模型中B7-H4和BTLA的异常表达

目的:通过检测肿瘤组织和肿瘤抗原诱导的小鼠脾脏巨噬细胞B7-H4表达、同时检测荷瘤小鼠T细胞BTLA的表达,以进一步探讨这一对新的负免疫调节分子在肿瘤免疫逃逸机制中的作用。方法:应用RT-PCR检测体外培养肿瘤细胞株3LL和Renca、荷瘤后小鼠肿瘤组织B7-H4mRNA以及荷瘤小鼠T细胞BTLA mRNA表达的改变;应用流式细胞术检测荷瘤小鼠脾脏巨噬细胞和肿瘤可溶性抗原诱导的正常小鼠脾脏巨噬细胞B7-H4表面蛋白表达的改变;应用免疫组化技术检测荷瘤后小鼠肿瘤组织B7-H4表面蛋白表达的改变。结果:在体外培养的肿瘤细胞株3LL和Renca上未检测到B7-H4mRNA的表达,小鼠成瘤后肿瘤组织和脾脏巨噬细胞在mRNA水平和蛋白质水平上均高表达B7-H4。另外荷瘤小鼠的T细胞较正常小鼠T细胞BTLA的表达明显增高。在体外肿瘤抗原刺激下,正常小鼠脾脏巨噬细胞B7-H4表达量明显上升;而用正常同样组织来源抗原刺激时,正常小鼠脾脏巨噬细胞B7-H4表达量未见显著改变。结论:B7-H4和BTLA这对协同刺激分子的异常表达可能在肿瘤逃逸免疫应答过程中起调节作用。     

A novel approach to the identification and enrichment of cancer stem cells from a cultured human glioma cell line

Enrichment of cancer stem cells for studies of carcinogenesis remains a difficult issue. We hypothesized that the unique features of cancer stem cells (CSCs) may allow formation of their colonies in vitro with distinct morphology. We therefore investigated the possibility to use morphological diversity of colonies to identify and enrich CSCs from cultured malignant human glioma cells. We found that a small proportion of the cells from a human glioma cell line U251 formed tight and round-shaped colonies in culture. Most cells in such colonies were capable of self-renewal, generating tumor spheres and differentiating into lineages with markers for neurons, astrocytes and oligodendrocytes. In addition, several neural stem cell-related genes were highly expressed by tumor cells in those tight colonies. Our results thus demonstrate a novel approach to the identification and enrichment of CSCs based on unique morphology of their colonies formed in vitro.     

Endothelial CD276 (B7-H3) expression is increased in human malignancies and distinguishes between normal and tumour-derived circulating endothelial cells

Background:

Mature circulating endothelial cells (CEC) are surrogate markers of endothelial damage. CEC measured in patients with advanced cancer are thought not only to derive from damaged normal vasculature (n-CEC), but also from damaged (t-CEC). Therefore, assays that allow the discrimination between these two putative types of CEC are thought to improve the specificity of the enumeration of CEC in cancer.

Methods:

Identification of tumour-associated endothelial markers (TEM) by comparing antigen expression on normal vs t-CEC and assess the presence of t-CEC in peripheral blood of cancer patients by incorporating TEM in our novel flow cytometry-based CEC detection assay.

Results:

No difference in antigen expression between normal and malignant endothelial cells (ECs) was found for CD54, CD109, CD137, CD141, CD144 and CXCR7. In contrast, overexpression for CD105, CD146, CD276 and CD309 was observed in tumour ECs compared with normal ECs. CD276 was most differentially expressed and chosen as a marker for further investigation. CD276-expressing CEC were significantly higher in 15 patients with advanced colorectal cancer (median 9 (range 1–293 cell per 4 ml); P<0.005), in 83 patients with a glioblastoma multiforme (median 10 (range 0–804); P<0.0001) and in 14 patients with advanced breast cancer (median 14 (range 0–390) P<0.05) as compared with 24 healthy individuals (median 3 (range 0–11)). Of all patients with malignancies, 58% had CD276⁺ CEC counts above the ULN (8 cell per 4 ml).

Conclusions:

The present study shows that CD276 can be used to discriminate ECs from malignant tissue from ECs from normal tissue. In addition, CD276⁺ CEC do occur in higher frequencies in patients with advanced cancer.     

Efficacy of the HSP90 inhibitor 17-AAG in human glioma cell lines and tumorigenic glioma stem cells

Glioblastoma multiforme (GBM) arises from genetic and signaling abnormalities in components of signal transduction pathways involved in proliferation, survival, and the cell cycle axis. Studies to date with single-agent targeted molecular therapy have revealed only modest effects in attenuating the growth of these tumors, suggesting that targeting multiple aberrant pathways may be more beneficial. Heat-shock protein 90 (HSP90) is a molecular chaperone that is involved in the conformational maturation of a defined group of client proteins, many of which are deregulated in GBM. 17-allylamino-17-demethoxygeldanamycin (17-AAG) is a well-characterized HSP90 inhibitor that should be able to target many of the aberrant signal transduction pathways in GBM. We assessed the ability of 17-AAG to inhibit the growth of glioma cell lines and glioma stem cells both in vitro and in vivo and assessed its ability to synergize with radiation and/or temozolomide, the standard therapies for GBM. Our results reveal that 17-AAG is able to inhibit the growth of both human glioma cell lines and glioma stem cells in vitro and is able to target the appropriate proteins within these cells. In addition, 17-AAG can inhibit the growth of intracranial tumors and can synergize with radiation both in tissue culture and in intracranial tumors. This compound was not found to synergize with temozolomide in any of our models of gliomas. Our results suggest that HSP90 inhibitors like 17-AAG may have therapeutic potential in GBM, either as a single agent or in combination with radiation.     

Pyruvate kinase M2 is a target of the tumor-suppressive microRNA-326 and regulates the survival of glioma cells

Emerging studies have identified microRNAs (miRNAs) as possible therapeutic tools for the treatment of glioma, the most aggressive brain tumor. Their important targets in this tumor are not well understood. We recently found that the Notch pathway is a target of miRNA-326. Ectopic expression of miRNA-326 in glioma and glioma stem cells induced their apoptosis and reduced their metabolic activity. Computational target gene prediction revealed pyruvate kinase type M2 (PKM2) as another target of miRNA-326. PKM2 has recently been shown to play a key role in cancer cell metabolism. To investigate whether it might be a functionally important target of miR-326, we used RNA interference to knockdown PKM2 expression in glioma cells. Transfection of the established glioma and glioma stem cells with PKM2 siRNA reduced their growth, cellular invasion, metabolic activity, ATP and glutathione levels, and activated AMP-activated protein kinase. The cytotoxic effects exhibited by PKM2 knockdown in glioma and glioma stem cells were not observed in transformed human astrocytes. Western blot analysis of human glioblastoma specimens showed high levels of PKM2 protein, but none was observed in normal brain samples. Strikingly, cells with high levels of PKM2 expressed lower levels of miR-326, suggestive of endogenous regulation of PKM2 by miR-326. Our data suggest PKM2 inhibition as a therapy for glioblastoma, with the potential for minimal toxicity to the brain.     

人脑胶质瘤组织中Oct4、Wnt2的表达及其临床意义

目的: 探讨Oct4和Wnt2在人脑胶质瘤组织中的表达及其与临床病理特征的关系。方法: 选取临床及病理资料完整的长江大学附属第一医院2006-2009年手术切除并经病理证实为胶质瘤的石蜡标本56例,采用免疫组织化学方法检测56例胶质瘤组织（其中15例为术后复发）和10例脑外伤行内减压术切除的脑组织标本Oct4、Wnt2的表达。结果: 正常脑组织中Oct4表达均为阴性,Wnt2表达仅1例呈弱阳性;56例胶质瘤组织中Oct4阳性34例（60.7%）,Wnt2阳性40例（714%）。Oct4、Wnt2在低度恶性胶质瘤组中和高度恶性胶质瘤中的阳性率分别为46.2%和73.3%（P<0.05）及577%和83.3%（P<0.05）,Oct4在复发肿瘤和初诊肿瘤中的阳性率分别为86.7%和51.2%（P<0.05）。人脑胶质瘤组织中 Oct4和Wnt2表达呈正相关（r=0.537,P<0.01）。结论: Oct4、Wnt2的表达与人脑胶质瘤的恶性程度相关,Oct4的表达与胶质瘤的复发相关;Oct4可能是通过Wnt通路而参与了胶质瘤的发生、发展。     

褪黑素联合顺铂通过诱导细胞凋亡抑制人胶质瘤细胞U251和SHG-44增殖

目的：研究褪黑素（melatonin,MT）和顺铂（cisplatin,DDP）单独或联合应用对人胶质瘤细胞U251和SHG-44增殖及凋亡的影响。方法：采用不同质量浓度MT和DDP单独或联合处理U251和SHG-44细胞,并设对照组（不加任何药物）及乙醇组（加入乙醇）;以CCK-8法检测细胞的增殖,流式细胞术检测细胞的凋亡和细胞周期,采用两药相互作用指数（coefficient of drug interaction,CDI）评估MT是否影响U251和SHG-44细胞对DDP的敏感性。结果：CCK-8结果显示,单用MT或DDP可浓度依赖性抑制U251和SHG-44细胞的增殖,MT还可协同增强DDP对U251和SHG-44细胞的增殖抑制作用（CDI<1）。流式细胞术检测结果显示,MT可促进U251和SHG-44细胞的凋亡,MT可增强DDP对U251和SHG-44细胞的凋亡诱导作用,0.5 mmol/L MT联合20 μg/ml DDP组U251和SHG-44的细胞凋亡率显著高于20 μg/ml DDP组\[（66.3±1.0）% vs （45.9±1.7）%,（35.5±0.8）% vs （15.5±0.8%）;均P<0.01\];而且0.5 mmol/L MT联合20 μg/ml DDP 组U251和SHG-44细胞的G1期比例显著高于20 μg/ml DDP组\[（52.4±2.1）% vs （27.9±1.5）%,（39.7±1.5）% vs （27.7±1.3）%;均P<001\]。结论：MT能显著增强DDP对人胶质瘤细胞U251和SHG-44的凋亡诱导作用,从而协同增强DDP对细胞增殖的抑制作用,有望成为人胶质瘤化疗的辅助药物。     

The cytotoxic action of lymphokine activated killer cells upon the human glioma cell line U251 is stimulated by bispecific monoclonal antibody (MoAb) constructs

The ability of IL-2 stimulated mononuclear cells to kill the human glioblastoma cell line U251 has been investigated. Highest cytotoxic activity was generated in low cell density cultures incubated for 15 days with 250–1000 U/ml IL-2. Sub-optimal killing was noted, with cells only exposed to IL-2 for three days. Under the latter conditions, bispecific monoclonal antibodies (MoAbs) of either anti-CD3 or anti-CD16 and an anti-NCAM MoAb stimulated LAK cell activity markedly. Anti-CD16 conjugates were found more effective than anti-CD3 and (Fab)₂ constructs more efficacious than those made with whole Ig molecules. Maximal stimulation of LAK cell activity was noted with bispecific MoAbs. Little effect was observed with either single or mixtures of monomeric MoAbs. Furthermore, no effect of bispecific MoAbs was observed when target cells lacked expression of NCAM. These results could be of clinical importance as it is not always feasible to screen LAK cells for optimal activity before administration to patients. Whilst bispecific MoAbs have no effect on optimally stimulated LAK cells, they are not inhibitory and can stimulate killing under sub-optimal IL-2 stimulation.     

CDH5 is specifically activated in glioblastoma stemlike cells and contributes to vasculogenic mimicry induced by hypoxia

Background

A proportion of glioblastoma stemlike cells (GSCs) expressing endothelial cell marker CDH5 (vascular-endothelial–cadherin or CD144) can transdifferentiate into endothelial cells and form blood vessels. However, the implications of CDH5 expression in gliomas and how it is regulated in GSCs remain to be clarified.

Methods

The mRNA and protein levels of CDH5 were detected in glioma samples and cultured cell lines, and the prognostic value of the CDH5 expression level for GBM patients was evaluated. Bioinformatics analysis was performed to reveal the potential functional roles of CDH5 in glioblastoma multiforme. Gene knockdown induced by short hairpin RNA, chromatin immunoprecipitation analysis, and a vasculogenic tube formation assay were performed to investigate the relationships among hypoxia, CDH5 expression level, and angiogenesis.

Results

CDH5 was overexpressed in gliomas, correlated with tumor grades, and was an independent adverse prognostic predictor for glioblastoma multiforme patients. CDH5 was specifically activated in GSCs but not in non-GSCs or neural stem cells, and CDH5⁺ cells could produce xenografts in immunocompromised mice. Bioinformatics analysis demonstrated that CDH5 might interact directly with hypoxia-inducible factor (HIF)2α. CDH5 expression was significantly upregulated in GSCs, but not in non-GSCs or normal neural stem cells, under a 1% O₂ condition. Both HIF1α and HIF2α positively regulated CDH5 level in GSCs and could bind to the promoter of CDH5. Furthermore, CDH5 contributed to the vasculogenic mimicry of GSCs, especially under hypoxic conditions.

Conclusions

The specific expression of CDH5 in GSCs may contribute to GSC-derived neovasculogenesis in glioblastoma multiforme, especially under hypoxic conditions, revealing novel tumorigenic mechanisms contributed by GSCs.