脑膜瘤中HIF-1α和COX-2的表达及与血管生成的关系

目的探讨缺氧诱导因子-1(HIF-1α)和环氧化酶-2(COX-2)在人脑膜瘤中表达的意义及与肿瘤血管形成的关系。方法应用免疫组织化学方法检测54例人脑膜瘤和10例正常脑组织中HIF-1α和COX-2的表达,用CD34抗体标记微血管并计数相应的微血管密度(MVD),对所得资料进行统计学分析。结果脑膜瘤组织中HIF-1α、COX-2表达均高于正常脑组织,差异有统计学意义(P<0.05);肿瘤组中MVD值(32.9±12.9)高于正常对照组(11.2±3.3),并且随病理分级的增高而增加(P<0.05);HIF-1α、COX-2表达与MVD存在显著相关性(rs=0.65、0.72,P均<0.01);HIF-1α与COX-2表达呈正相关(rs=0.35,P<0.01)。结论HIF-1α和COX-2的表达异常在脑膜瘤的发生发展中起重要作用,并且在促进肿瘤血管形成过程中两者可能起协同作用。     

脑膜瘤缺氧诱导因子-lα表达与瘤周血管生成及病理级别的关系及意义

目的探讨脑膜瘤缺氧诱导因子-lα(HIF-lα)表达与瘤中血管生成及病理级别之间的关系,探讨HIF-lα在脑膜瘤发生和发展中的作用,为治疗脑膜瘤提供理论依据。方法选取脑膜瘤标本45例,正常脑组织标本10例(均为重型颅脑损伤急症行内减压术)作为对照。采用免疫组化ElivisionTMplus两步法,检测缺氧诱导因子-lα在脑膜瘤标本和正常脑组织标本中的表达,以人原始造血细胞(CD34)标记肿瘤微血管,用微血管密度(MVD)作为血管生成指标测定肿瘤血管生成,比较缺氧诱导因子-lα表达与血管生长及病理级别关系。结果45例脑膜瘤组织切片中有23例表达HIF-1α,染色阳性率为51.1%,HIF-1α在正常脑组织及脑膜瘤Ⅰ级、Ⅱ级、Ⅲ级中的阳性表达率分别为0.00%、32.00%、66.67%和87.50%。在各个级别的脑膜瘤及正常脑组织中,HIF-1α的阳性表达率间差异有显著性(P<0.05)。正常脑组织组、I、II和III级脑膜瘤组中的MVD值分别为10.34±2.78,17.25±2.69,20.43±5.20和30.79±5.64,MVD值随着脑膜瘤级别的升高逐渐增加。HIF-lα表达程度与MVD呈正相关。结论缺氧诱导因子-lα表达强度与脑膜瘤血管生成可能有关,为治疗脑膜瘤提供了新的思路。     

缺氧诱导因子-1的表达与脑膜瘤血管生成的关系

目的探讨缺氧诱导因子-1(HIF-1)的表达与脑膜瘤血管生成的关系。方法采用免疫组织化学方法检测48例脑膜瘤和10例正常脑膜组织中氧诱导因子-1α(HIF-1α)的表达,并用人原始造血细胞(CD34)抗体标记血管内皮细胞,计数脑膜瘤和正常脑膜组织中的微血管密度(MVD),对所得资料进行统计学分析。结果48例脑膜瘤组织中,HIF-1α阳性表达率为79%,其中弱阳性( ),阳性( ),强阳性( )表达率分别为33%,31%,15%;MVD为6~55,x±s为28±11;正常脑膜中无HIF-1α表达,MVD为4±1,明显低于肿瘤组织,差异有显著性(P<0.01)。HIF-1α阴性(-)表达者,MVD为11±5;呈弱( )、中( )及强阳性( )表达者,MVD分别为23±10、36±13及47±15;HIF-1α阳性表达程度与MVD呈正相关(rs=0.766,P<0.01)。结论HIF-1的表达与脑膜瘤血管生成密切相关,进一步研究HIF-1在脑膜瘤中的表达及调控血管生成的机制,可能为脑膜瘤的治疗开辟新途径。     

缺氧诱导因子-lα和血管内皮生长因子在人脑胶质瘤中的表达及意义

目的:探讨缺氧诱导因子-1α(HIF-1α)、血管内皮生长因子(VEGF)和微血管密度(MVD)在人脑胶质瘤中的表达情况,分析三者的关系及其意义。方法:应用免疫组化方法分析62例人脑胶质瘤中HIF-1α、VEGF、和MVD的表达情况。结果:本组HIF-1α的总阳性表达率是66.1%,它们在正常脑组织和Ⅰ-Ⅱ、Ⅲ、Ⅳ肿瘤组织的阳性率分别为0%、39.3%、81.8%、100%与正常对照组比较有显著性差异(P<0.01)。HIF-1α表达水平与胶质瘤恶性度存在相关性(P<0.01)。VEGF在HIF-1α阳性组中的阳性率(95.1%)明显高于HIF-1α阴性组中的VEGF的阳性率47.6%(P<0.01)。结论:HIF-1α和VEGF的表达与MVD存在正相关关系;VEGF与HIF-1α表达呈正相关性,二者与人脑胶质瘤的病理分级呈正相关,与脑胶质瘤新生血管生成有关。     

COX-2和VEGF在人脑膜瘤中的表达以及其与血管生成的关系

目的 观察人脑膜瘤组织中环氧化酶-2(COX-2)的表达,探讨其对血管生成的影响.方法 应用免疫组织化学方法对72例人脑膜瘤和20例非肿瘤脑组织的COX-2、血管内皮生长因子(VEGF)的表达和微血管密度(MVD)值进行测定,COX-2和VEGF的表达用评分表衡量.结果 COX-2在人脑膜瘤巾的中度及以上表达(50/72,69.4%)、VEGF在人脑膜瘤中的中度阳性表达(37/72,51.4%),显著高于其在非肿瘤组织中的表达(分别为2/20,10%及1/20,5%),并随肿瘤恶性程度增高而增高,具有明显的相关性.结论 COX-2的过度表达可能在人脑膜瘤的发生、发展中起到重要作用,对肿瘤的血管生成有重要的促进作用.     

脑膜瘤内的血管分布和血管生成与HIF-1α、VEGF的关系

目的 探讨脑膜瘤内部的血管分布以及缺氧诱导因子-1α(HIF-1α)、血管内皮生长因子(VEGF)与脑膜瘤血管生成的关系. 方法 选取中山大学附属一院和中山市人民医院神经外科自2010年5月至2011年3月间手术切除并经病理证实的人脑膜瘤标本15例,收集每例标本硬膜鼠尾征处、基底中心、瘤中央、瘤缘4个不同部位的脑膜瘤组织,每个部位分别连续切片3张,应用免疫组化染色检测CD34、VEGF、HIF-1α的分布和表达. 结果 CD34主要表达在细胞膜和细胞浆,染色呈棕黄色颗粒,VEGF定位于肿瘤细胞胞浆内,而HIF-1α主要在细胞核,少量在胞浆.尾征和瘤缘部位MVD、VEGF、HIF-1α的表达高于基底中心和瘤中央,差异有统计学意义(P＜0.05).脑膜瘤MVD与VEGF、MVD与HIF-1α、VEGF与HIF-1α表达之间均呈正相关关系(r=0.960,P=0.040;r=0.964,P=0.036;=0.998,P=0.002). 结论 脑膜瘤外周部的血管生成比中央区丰富;HIF-1α、VEGF在诱导并促进脑膜瘤的血管生成方面发挥一定作用.     

缺氧诱导因子-1与脑膜瘤血管生成

缺氧诱导因子1是细胞在缺氧条件下产生的具有转录活性的核蛋白,由α亚单位和β亚单位构成,其中α亚单位被认为是特异性氧调节亚单位,决定了HIF1的活性。大量研究发现HIF1是肿瘤血管生成信号途径的关键性上游转录调控因子,通过影响其他血管生长因子的表达,而直接参与血管生成的全程。脑膜瘤是常见的颅内肿瘤,多呈实体性且血供丰富,在颅内呈膨胀性或侵袭性生长,其发生、发展与血管生成密切相关。深入研究HIF1在脑膜瘤中的表达及其对血管生成的调控可能为脑膜瘤的治疗发现新方法。     

缺氧诱导因子-1α、血管内皮生长因子与脑膜瘤血管生成、肿瘤恶性程度的关系

采用免疫组织化学二步法对48例脑膜瘤及9例瘤旁正常脑组织中的缺氧诱导因子-1α(HIF-1α)和血管内皮生长因子(VEGF)的表达进行研究，以探讨脑膜瘤组织血管生成及其与临床预后的关系。     

环氧化酶-2在脑膜瘤中的表达及意义

目的通过检测环氧化酶-2（COX-2）在人脑膜瘤、正常脑膜组织中的表达，探讨COX-2在人脑膜瘤发生、发展过程中的作用。方法采用免疫组织化学方法检测人脑膜瘤、正常脑膜组织中COX-2的表达及其与脑膜瘤的病理分级、侵袭性、瘤周水肿等临床病理因素的关系。结果47例脑膜瘤组织中，36例有COX-2表达，阳性表达率为76．6％，正常脑膜无COX-2表达。COX-2在患者的年龄（P〉0．05）、性别（P〉0．05）之间的表达差异无统计学意义，而在肿瘤病理分级（P〈0.01）、侵袭性（P〈0．05）、瘤周水肿（P〈0．05）之间的表达差异有统计学意义。结论COX-2在脑膜瘤中普遍表达，其与脑膜瘤的病理分级、侵袭性、瘤周水肿等临床病理因素密切相关，COX-2可能在人脑膜瘤的发生发展中起重要作用。     

环氧化酶-2在脑膜瘤中的表达及意义

目的 通过检测环氧化酶-2(cyclooxygenase-2 ,COX-2)在人脑膜瘤、正常脑膜组织中的表达,探讨COX-2在人脑膜瘤发生、发展中的作用.方法 采用免疫组织化学方法(S-P法)检测人脑膜瘤、正常脑膜组织中COX-2的表达及其与脑膜瘤的病理分级、侵袭性、瘤周水肿等临床病理因素的关系.结果 47例脑膜瘤组织中,36例有COX-2表达,阳性表达率为76.6%,正常脑膜无COX-2表达. COX-2的表达在患者的年龄 (P=0.897)、性别(P=0.951)之间差异无统计学意义,而在肿瘤病理分级(P =0.001)、侵袭性(P=0.022)、瘤周水肿(P=0.014)之间差异有统计学意义.结论 COX-2在脑膜瘤中普遍表达,与脑膜瘤的病理分级、侵袭性、瘤周水肿等临床病理因素密切相关, COX-2可能在人脑膜瘤的发生发展中起重要作用.     

缺氧诱导因子-1α在胶质瘤中的表达与意义

目的探讨缺氧诱导因子-1α（HIF-1α）在胶质瘤中的表达及其临床意义。方法用免疫组化方法分别检测80例胶质瘤中HIF-1α的表达,其中I级胶质瘤、Ⅱ级胶质瘤、Ⅲ级胶质瘤、Ⅳ级胶质瘤各20例,以10例瘤周正常脑组织为对照。结果HIF-1α在Ⅰ、Ⅱ、Ⅲ、Ⅳ级胶质瘤的阳性率分别为20％、50％、75％、95％,在正常脑组织中无表达,各组间有显著差异（Х^2=40．26,P〈0．01）;各级胶质瘤表达强度随胶质瘤病理级别增加而增加（r=0．6977,P〈0．001）。HIF-1α表达与患者年龄、性别、肿瘤大小、部位无关。结论HIF-1α在胶质瘤中的表达强度可以作为判断胶质瘤生物学行为、预测患者预后的重要指标。     

Cyclooxygenase-2 and inducible nitric oxide synthase expression in human astrocytic gliomas: correlation with angiogenesis and prognostic significance

Angiogenesis, which plays a key role in the development of astrocytic gliomas, depends on the local balance between various molecules that induce and inhibit neovascularization. Whereas recent experimental studies have indicated that cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) regulate angiogenesis by modulating vascular endothelial growth factor (VEGF) production, little is known about the relationships among expression of these markers, angiogenesis, and clinical outcome in astrocytic glioma cases. We therefore examined immunohistochemical expression of COX-2, iNOS, and VEGF in 51 high-grade astrocytomas including 31 glioblastomas (grade IV) and 20 anaplastic astrocytomas (grade III), 49 low-grade astrocytomas (grade II), and 43 reactive astrogliosis specimens, and determined the relationship with microvessel density (MVD) and prognostic significance. Stepwise increase of immunoreactive scores for COX-2, iNOS, and VEGF was found from astrogliosis, through low-grade to high-grade astrocytoma. The COX-2 expression strongly correlated with iNOS, VEGF, and high MVD, both overall and in all tumors, whereas iNOS expression was weakly associated with VEGF and high MVD. Univariate analysis revealed a significant association between COX-2 overexpression and a poor outcome. The findings for COX-2 and VEGF-related angiogenesis raise the possibility that the COX-2 pathway may contribute to astrocytic tumorigenesis by promoting new vessel formation with prognostic implications.     

缺氧诱导因子-1α和血管内皮生长因子与垂体腺瘤侵袭性的研究

目的研究缺氧诱导因子-1α（HIF-1α）和血管内皮生长因子（VEGF）在人垂体腺瘤中的表达，探讨其表达水平与垂体腺瘤血管生成和侵袭性的关系。方法即用型免疫试剂盒检测23例垂体腺瘤中HIF-1α和VEGF的表达情况，比较两者表达的相关性；同时对表达水平与患者的临床资料进行统计学分析。结果HIF-1α和VEGF与垂体腺瘤的侵袭性密切相关（P〈0．05）。结论HIF-1α和VEGF可能通过促进新生血管形成刺激垂体腺瘤生长和侵袭，其作用机制有待进一步研究。     

脑膜瘤组织VEGF／VPF、KDR的表达及意义

目的研究脑膜瘤血管生成及瘤周脑水肿与VEGF/VPF及其受体KDR的关系。方法采用Northern印迹分子杂交和免疫组化技术检测47例脑膜瘤组织VEGF/VPFmRNA、VEGF/VPF和KDR蛋白表达,分析其与微血管密度(MVD)和瘤周脑水肿度DPTBE的关系。结果47例脑膜瘤均表达4.2Kb的VEGF/VPFmRNA片段,VEGF/VPF蛋白表达与其mRNA的表达一致,80.9%的肿瘤KDR蛋白表达阳性,VEGF/VPF和KDR分别定位于脑膜瘤瘤细胞和血管内皮细胞胞浆。VEGF/VPFmRNA表达与脑膜瘤MVD和DPTBE呈正相关r=0.67,P<0.01r=0.54,P<0.01;KDR阳性组脑膜瘤VEGF/VPFmRNA表达水平、MVD、DPTBE均显著高于KDR阴性组(P<0.01)。结论脑膜瘤细胞可产生VEGF/VPF,通过KDR介导促肿瘤血管生成和增加血管通透性,在脑膜瘤瘤周脑水肿的发生发展过程中起重要作用。     

Hypoxia-induced upregulation of pigment epithelium-derived factor by retinal glial (Müller) cells

Neuronal degeneration and aberrant neovascularization are common problems of ischemic retinopathies. Pigment epithelium-derived factor (PEDF), a neuroprotective protein and an inhibitor of angiogenesis, is produced by retinal glial (Müller) cells and can counterbalance elevated levels of vascular endothelial growth factor (VEGF), the expression of which is regulated primarily by hypoxia-inducible factor (HIF)-1. In an approach to mimic transient ischemia in vitro, primary Müller cells were cultured under transient and strong hypoxia (0.2% O(2) ), followed by reoxygenation at 2.5% O(2) , and molecular mechanisms that might contribute to changes in the intraretinal PEDF level were determined. Hypoxic conditions caused an increasing expression of HIF-1α and led to upregulation of both PEDF and VEGF. Treatment of the cells with synthetic HIF-1α blockers or neutralization of VEGF binding to VEGF receptors (VEGFR-1 and-2) suppressed hypoxia-induced PEDF upregulation. Furthermore, the presence of CoCl(2) (a hypoxia mimetic) induced an accumulation of elevated HIF-1α protein in the nucleus and an upregulation of PEDF expression in Müller cells. Increasing PEDF expression was attenuated when HIF-1α levels were suppressed using HIF-1α small interfering RNA (siRNA). On the other hand, siRNA-mediated depletion of PEDF facilitated HIF-1α upregulation caused by CoCl(2) and resulted in increasing VEGF mRNA and protein levels. These results demonstrate that VEGF and PEDF may be unidirectionally regulated in hypoxia through HIF-1α activation, with upregulation of PEDF, which may occur in a VEGF-dependent manner. However, endogenously produced PEDF seems to be an inherent control element of HIF-1α expression in Müller cells, indicating an important feedback mechanism for limiting upregulation of VEGF.     

葡萄糖转运蛋白-3及缺氧诱导因子1α在星形细胞瘤中的表达

目的 探讨葡萄糖转运蛋白-3(GLUT-3)和缺氧诱导因子(HIF)-1α在星形细胞瘤中的表达及其临床意义.方法 应用免疫组化染色和RT-PCR方法检测80例星形细胞瘤患者肿瘤组织中GLUT-3和HIF-1α表达情况,另取10例星形细胞瘤周围做内减压切除的正常脑组织为对照.结果 GLUT-3在Ⅰ、Ⅱ、Ⅲ、Ⅳ级星形细胞瘤中阳性表达率分别为35%、60%、80%、100%,HIF-1α在Ⅰ、Ⅱ、Ⅲ、Ⅳ级星形细胞瘤中阳性表达率分别为20%、50%、75%、95%,两者呈正相关关系(r=0.550,P=0.000).GLUT-3 mRNA表达在Ⅰ、Ⅱ、Ⅲ、Ⅳ级星形细胞瘤中分别为0.19±0.03、0.45±0.12、0.67±0.11、0.89±0.19,HIF-1α mRNA在Ⅰ、Ⅱ、Ⅲ、Ⅳ级星形细胞瘤中分别为0.21±0.06、0.48±0.11、0.72±0.16、0.93±0.12,各级别间比较差异均有统计学意义(P=0.000),且GLUT-3 mRNA、HIF-1αmRNA表达强度与星形细胞瘤的病理分级呈正相关关系(r=0.887,P=0.000;r=0.813,P=0.000),二者之间也呈正相关关系(r=0.530,P＜0.05).结论 GLUT-3与HIF-1α表达强度和星形细胞瘤的病理分级成正相关,可以作为判断星形细胞瘤生物学行为的重要指标.

Abstract：

Objective To explore the expressions and clinical significances of glucose transporter protein-3 (GLUT-3) and hypoxia-inducible factor-1α (HIF-1α) in astrocytoma. Methods The astrocytoma tissues from 80 patients with astrocytoma were chosen as experimental group; and the normal cerebral tissues from another 10 patients performed depression around the astrocytoma were chosen as control group. Immunohistochemistry and RT-PCR were employed to detect the GLUT-3 and HIF-1α expressions in these tissues. Results The protein of GLUT-3 in grade Ⅰ, grade Ⅱ, grade Ⅲ and grade Ⅳ astrocytomas were positively expressed, respectively, as 35%, 60%, 80% and 100% by immunohistochemistry; the protein of HIF-1α in grade Ⅰ, grade Ⅱ, grade Ⅲ and grade Ⅳ astrocytomas were positively expressed, respectively, as 20%, 50%, 75% and 95% by immunohistochemistry; positive correlation was noted between the protein levels of GLUT-3 and HIF-1α (r=0.550, P=0.000). The mRNA levels of GLUT-3 in grade Ⅰ, grade Ⅱ, grade Ⅲ and grade Ⅳ astrocytomas were expressed, respectively,as 0.19±0.03, 0.45±0.12, 0.67±0.11 and 0.89±0.19 by RT-PCR; the mRNA levels of HIF-1α were expressed, respectively, as 0.21 ±0.06, 0.48±0.11, 0.72±0.16 and 0.93±0.12 by RT-PCR; and the mRNA expression level of GLUT-3 were positively correlated to that of HIF-1α (r=0.530, P=0.000).Significant difference between each 2 different pathological grades of astrocytoma was noted (P＜0.05). The mRNA expression levels of GLUT-3 and HIF-1α were positively correlated to the pathological grades of astrocytomas (r=0.887, P=0.000; r=0.813, P=0.000). Conclusion The expression of GLUT-3 and HIF-1α in astrocytoma are significantly correlated to tumors' pathology grade, which can be taken as a useful marker for predicting the biological behavior.     

Role of vincristine in the inhibition of angiogenesis in glioblastoma

Objective: Vincristine, a microtubule-destabilizing drug, was found to exhibit anti-angiogenic effects and anti-tumoral activity. However, the precise mechanism by which vincristine inhibits angiogenesis in glioblastomas is not well understood. Our aim was to investigate whether vincristine affects vascular endothelial growth factor (VEGF) expression in glioblastoma cells and determine whether it is mediated by the downregulation of hypoxia-inducible factor-1α (HIF-1α).

Methods: We investigated the expression of HIF-1α in glioblastoma tissues resected from patients and in human glioblastoma cell lines using immunohistochemistry, Western blot analysis, and immunocytochemistry. In addition to an MTT assay assessing the effect of vincristine on cell proliferation and viability, the effects of vincristine on VEGF mRNA expression and HIF-1α protein were examined using real-time RT-PCR and Western blot analysis under 1% O₂ (hypoxia).

Results: HIF-1α was expressed in the majority of glioblastoma tissues and was detected mainly in the nucleus. Strong immunoreactivity for HIF- 1 α was found often in the hypercellular zones. Under hypoxic conditions, HIF-1α protein levels in the glioblastoma cell lines increased, primarily localizing into the nucleus similar to glioblastoma tissues. Exposure of glioblastoma cells to vincristine resulted in enrichment of the G₂-M fraction of the cell cycle, which suggests that vincristine-mediated growth inhibition of glioblastoma is correlated with mitotic inhibition. Using doses lower than those found to reduce the viability and proliferation of cells by 50% (IC₅₀), vincristine decreased both the expression of VEGF mRNA and the level of HIF-1α protein in hypoxic glioblastoma cells. In addition, following exposure to vincristine, the expression of VEGF mRNA was correlated with HIF-1α protein levels.

Conclusions: Our results suggest that the mechanism by which vincristine elicits an anti-angiogenic effect in glioblastomas under hypoxic conditions might be mediated, in part, by HIF-1α inhibition.     

Increased ratio of vascular endothelial growth factor to semaphorin3A is a negative prognostic factor in human meningiomas

Semaphorin3A (SEMA3A) is an anti‐angiogenic factor which is expressed in human meningiomas in association with low microvessel density (MVD). It competes with vascular endothelial growth factor (VEGF) for receptor neuropilin‐1 (NRP‐1). The ratio between VEGF and SEMA3A has been recently demonstrated to regulate neo‐angiogenesis, proliferation and progression of tumors. To clarify the involvement of these proteins in the above‐mentioned phenomena, we analyzed the immunohistochemical expression of SEMA3A, VEGF and NRP‐1 and their correlation with MVD in a series of 48 cases of meningioma with different histotype and histological grade. SEMA3A and VEGF expression was encountered in about half the cases, although at different levels. NRP‐1 staining was evidenced in the vessels within all but two tumors and in the neoplastic cells of 18/48 meningiomas. A negative significant correlation emerged between SEMA3A amount and MVD; on the other hand, high VEGF levels appeared to be significantly associated with high MVD. A high VEGF/SEMA3A was significantly associated with high histological grade, proliferation index and MVD as well as with a higher recurrence rate of the meningiomas. Present data suggest that the balance between the expression of the pro‐angiogenic factor VEGF and the anti‐angiogenic SEMA3A may be involved in the regulation of neo‐angiogenesis and proliferation in meningiomas, representing also a predictor of recurrences in these tumors. Further validation of our results may open the way for the use of drugs targeting not only VEGF, but also NRP‐1 and SEMA3A to prevent recurrences of meningiomas.