Expression and regulation of neuropilin-1 in human astrocytomas

Vascular endothelial growth factor (VEGF), through activation of its endothelial receptors VEGFR-1 and VEGFR-2, is an important positive modulator of tumor angiogenesis and edema in solid tumors such as malignant astrocytomas. Neuropilin-1 (Npn-1) is a transmembrane receptor expressed by both endothelial and non-endothelial cells, including tumor cells. Npn-1 has been postulated to function as a co-factor in activation of the biologically relevant VEGFR-2, by the most abundant VEGF165 isoform. However, the function of Npn-1 in normal and pathological angiogenesis, its expression pattern in relation to VEGF in tumors such as astrocytomas and whether it is similarly or differentially regulated compared to VEGF remain unknown. In our study, the expression pattern of Npn-1 and VEGF by human astrocytoma cell lines and specimens was closely correlated and associated with malignant astrocytomas. Mitogens, such as epidermal growth factor and activation of p21-Ras, previously demonstrated to be relevant in astrocytoma proliferation and induction of VEGF, also induce Npn-1 expression. Hypoxia, the main physiological inducer of VEGF expression, decreased Npn-1 expression. Increased Npn-1 expression was also demonstrated in a transgenic mouse astrocytoma model. Astrocytomas are an ideal system for furthering our understanding of the functional relevance, if any, of Npn-1 in tumor angiogenesis.     

nNav1.5在人脑星形细胞瘤中的表达及意义

目的:研究nNav1.5 mRNA及蛋白在人脑星形细胞瘤组织和正常脑组织中的表达差异.方法: 采用逆转录聚合酶链反应(RT-PCR)及western blot法分别检测nNav1.5 mRNA及蛋白在30例人脑星形细胞瘤组织和8例正常脑组织中的表达水平.结果: 人脑星形细胞瘤组织中nNav1.5基因及蛋白的表达值显著高于正常脑组织(P<0.01),且随病理级别的增高而升高.结论: nNav1.5 mRNA及蛋白在人脑星形细胞瘤组织中的表达水平显著升高,这可能与星形细胞瘤细胞增殖活跃及侵袭性生长等生物特性有关.     

人星形细胞瘤血管内皮生长因子表达

目的:探讨VEGF在星形细胞瘤中表达与星形细胞瘤组织学分级和患者年龄的关系.方法:应用免疫组化方法检测52例星形细胞瘤石蜡包埋病理切片.结果:VEGF在不同病理级别星形细胞瘤中表达程度不同,随组织级别增加,表达增强.VEGF高表达组患者平均年龄高于低表达组.结论:VEGF与星形细胞瘤生长及恶性进展关系密切,VEGF高表达与高龄有关,预示预后不良.     

nNavl．5在人脑星形细胞瘤中的表达及意义

目的：研究nNav1．5mRNA及蛋白在人脑星形细胞瘤组织和正常脑组织中的表达差异。方法：采用逆转录聚合酶链反应（RT—PCR）及western blot法分别检测nNav1．5mRNA及蛋白在30例人脑星形细胞瘤组织和8例正常脑组织中的表达水平。结果：人脑星形细胞瘤组织中nNav1．5基因及蛋白的表达值显著高于正常脑组织（P〈0．01）,且随病理级别的增高而升高。结论：nNav1．5mRNA及蛋白在人脑星形细胞瘤组织中的表达水平显著升高,这可能与星形细胞瘤细胞增殖活跃及侵袭性生长等生物特性有关。     

促血管生成素在大肠癌组织的表达及其临床病理意义

目的　观察促血管生成素（Ａｎｇ）-１、Ａｎｇ-２及其受体Ｔｉｅ-２在大肠癌中的表达,探讨其与大肠癌血管生成的关系及临床病理意义。方法　采用免疫组化ＰＶ-９０００二步法观察５０例大肠癌和１０例正常大肠黏膜组织中Ａｎｇ-１、Ａｎｇ-２、Ｔｉｅ-２的表达,采用ＣＤ１０５标记检测微血管密度（ＭＶＤ）。结果　大肠癌组织Ａｎｇ-１的表达低于正常大肠黏膜,Ａｎｇ-２、Ｔｉｅ-２的表达高于正常大肠黏膜,差异均有统计学意义（Ｐ＜０.０５）;Ａｎｇ-１、Ａｎｇ-２的表达在不同分化程度间差异有统计学意义（Ｐ＜０.０１）;Ａｎｇ-１在淋巴结转移组的表达低于无转移组（Ｐ＜０.０５）;Ａｎｇ-２在淋巴结转移组高于无转移组（Ｐ＜０.０５）,在Ｄｕｋｅｓ'Ｃ、Ｄ期明显高于Ｄｕｋｅｓ'Ａ、Ｂ期（Ｐ＜０.０１）;Ｔｉｅ-２在淋巴结转移组的表达高于无转移组（Ｐ＜０.０５）;Ａｎｇ-２、Ｔｉｅ-２的表达与ＭＶＤ均呈正相关（ｒ＝０.３４５,Ｐ＜０.０５;ｒ＝０.２９９,Ｐ＜０.０５）。结论　促血管生成素与大肠癌的病理分化程度、Ｄｕｋｅｓ分期、淋巴结转移有关,并且在大肠癌血管生成过程中发挥重要作用。     

Expression and aberrant promoter methylation of Wnt inhibitory factor-1 in human astrocytomas

Background

Wnt inhibitory factor-1(WIF-1) acts as a Wnt-antagonists and tumor suppressor, but hypermethylation of WIF-1 gene promoter and low expression activate Wnt signaling aberrantly and induce the development of various human tumors. With this work we intended to investigate the expression and promoter methylation status of WIF-1 gene in human astrocytomas.

Methods

The tissue samples consisted of 53 astrocytomas and 6 normal brain tissues. The expression levels of WIF-1 were determined by immunohistochemistry and semiquantitative RT-PCR. The results were analyzed in correlation with clinicopathological data. Methylation status of WIF-1 gene promoter was investigated using methylation specific PCR. The relationship between methylation and expression of the genes was analyzed.

Results

The average expression levels of WIF-1 protein and mRNA in astrocytomas were decreased significantly compared with normal control tissues. The protein and mRNA expression of WIF-1 gene in astrocytomas was decreased with the increase of pathological grade. Furthermore, WIF-1 promoter methylation was observed by MS-PCR in astrocytomas which showed significant reduction of WIF-1 expression. The WIF-1 promoter hypermethylation was associated with reduced expression of WIF-1 expression.

Conclusion

Our results demonstrate that the WIF-1 gene is frequently down-regulated or silenced in astrocytomas by aberrant promoter methylation. This may be an important mechanism in astrocytoma carcinogenesis.     

Expression and localization of scatter factor/hepatocyte growth factor in human astrocytomas

Scatter factor/hepatocyte growth factor (SF/HGF) is a pleiotropic cytokine that has been implicated in glioma invasion and angiogenesis. The SF/HGF receptor, MET, has been found to be expressed in neoplastic astrocytes as well as in endothelial cells of the tumor vasculature. Both SF/HGF and MET expression have also been described to correlate with the malignancy grade of human gliomas. However, most glioblastoma cell lines lack SF/HGF expression, raising the question of the cellular origin of SF/HGF in vivo. Using in situ hybridization, we analyzed glioblastomas, anaplastic astrocytomas, diffuse astrocytomas, pilocytic astrocytomas, and normal brain for the expression of SF/HGF mRNA. We detected strong SF/HGF expression by the majority of the tumor cells and by vascular endothelial cells in all glioblastoma specimens analyzed. Combined use of in situ hybridization with fluorescence immunohistochemistry confirmed the astrocytic origin of the SF/HGF-expressiong cells. In contrast, CD68-immunoreactive microglia/macrophages, as well as vascular smooth muscle cells reactive to alpha-smooth muscle actin, lacked SF/HGF expression. In anaplastic, diffuse, and pilocytic astrocytomas, SF/HGF expression was confined to a subset of tumor cells, and signals were less intense than in glioblastomas. In addition, we detected SF/HGF mRNA in cortical neurons. SF/HGF expression was not up regulated around necroses or at tumor margins. MET immunoreactivity was observed in GFAP-expressing astrocytic tumor cells and endothelial cells as well as in a subset of microglia/macrophages. We conclude that in vivo, both autocrine and paracrine stimulation of tumor cells and endothelium through the SF/HGF-MET system are likely to contribute to tumor invasion and angiogenesis. Lack of SF/HGF expression by most cultured glioblastoma cells is not representative of the in vivo situation and most likely represents a culture artifact.     

Expression of stem cell markers in human astrocytomas of different WHO grades

According to new hypotheses astrocytomas/gliomas either arise from or attract neural stem cells. Biological markers, particularly antigenic markers, have played a significant role for the characterization of these tumour stem cells (TSCc). Because these studies have been performed with single experimental samples mostly from gliomas, we investigated the expression of the stem cell markers CD133/Prominin, Nestin, Sox-2, Musashi-1, CXCR4, Flt-4/VEGFR-3 and CD105/Endoglin in 72 astrocytomas of different WHO-grades and compared it to normal adult human brain. Expression of their mRNA was quantified by quantitative RT-PCR, of their protein by counting immunopositive cells. In contrast to normal brain, tumour samples showed a high variability for the expression of all markers. However, their mean expression was significantly increased in astrocytomas, but this depended on the WHO grade only for CD133, Nestin, Sox-2 and Musashi-1. Confocal microscopy revealed that these markers mostly could be co-stained with glial fibrillary acidic protein, a marker for astoglial cells, but less frequently with the proliferation marker Ki-67/MIB-1. These markers sometimes, but not necessarily could be co-stained with each other in complex patterns. Our results show that most astrocytomas contain considerable portions of cells expressing stem cell markers. It appears that some of these cells originate from tumour genesis (supporting the stem cell hypothesis) while others are attracted by the tumours. Further functional markers are required to differentiate these TSC-types.     

EphB4/EphrinB2在人脑星形细胞瘤中的表达及其病理学意义

目的：探讨EphrinB2与其受体EphB4、微血管密度（mierovessel density，MVD）和Ki-67在人脑星形细胞瘤中的表达及其病理学意义。方法：采用组织芯片技术和Maxvision^TM快捷免疫组织化学染色方法检测84例人脑星形细胞瘤和12例外伤脑组织中EphB4／EphrinB2、MVD和Ki-67的表达。结果：EphB4／EphrinB2、MVD、和Ki-67标记指数（Ki-67 labelling index．Ki-67LI）在人脑星形细胞瘤组和对照组之间的差异有统计学意义（P〈0．05）。EphB4、EphrinB2、MVD和Ki-67 LI与肿瘤级别呈正相关，MVD和Ki-67 LI与EphB4或EphrinB2蛋白表达正相关，有统计学意义（P〈0．05）。结论：EphB4和EphrinB2与人脑星形细胞瘤的分化程度和肿瘤血管生成密切相关，EphB4和EphrinB2的过度表达对肿瘤发展和促进肿瘤血管的生成起重要作用。利用EphB4／EphrinB2、MVD和Ki-67来判断人脑星形细胞瘤的恶性程度和病理特征，是一个较好的参考指标。     

Expression of angiopoietins and its clinical significance in non-small cell lung cancer

Angiopoietin (Ang)-1 and -2 have been recently identified as potent angiogenic factors which function in concert with vascular endothelial growth factor (VEGF), but no detailed clinical study on Ang expression has been reported. To assess the clinical significance of Ang expression in non-small cell lung cancer (NSCLC), a total of 236 patients with pathological stage-I-IIIA disease were retrospectively reviewed. Expression of Ang-1, Ang-2, or VEGF was examined immunohistochemically; intratumoral microvessel density (IMVD) was examined with immunohistochemical staining against CD34, a marker of pan-endothelial cells (CD34-IMVD), and that against CD105, a marker of proliferative endothelial cells (CD105-IMVD). Positive expression of Ang-1 and that of Ang-2 were seen in 101 (42.8%) and 40 patients (16.9%), respectively. There was no significant correlation between Ang-1 expression and CD34-IMVD or CD105-IMVD. In contrast, the average CD105-IMVD for Ang-2-positive tumor was significantly higher than that for Ang-2-negative tumor (56.7 versus 38.5; P = 0.032). More interestingly, such an angiogenic effect of Ang-2 was seen only when VEGF expression was high; when VEGF expression was high, the average CD105-IMVD for Ang-2-positive tumor was significantly higher than that for Ang-2-negative tumor (89.1 versus 63.6; P = 0.045); when VEGF expression was low, the average CD105-IMVD for Ang-2-positive tumor and that for Ang-2-negative tumor were almost the same (27.4 and 27.1, respectively). Moreover, positive expression of Ang-2, not Ang-1, was a significant factor to predict a poor postoperative survival (5-year survival rates for Ang-2-positive patients and -negative patients were 53.5 and 70.3%, respectively; P = 0.027), which was confirmed by a multivariate analysis. The influence of Ang-2 status on postoperative survival was enhanced when VEGF expression was high. That said, the 5-year survival of Ang-2-positive and VEGF-high patients was extremely low (41.4%) as compared with that for Ang-2-negative and VEGF-low patients (66.6%), as compared with that for Ang-2-positive and VEGF-low patients (63.6%), and as compared with that for Ang-2-negative and VEGF-low patients (71.8%). In conclusion, positive Ang-2 expression was significantly correlated with a poor prognosis, as well as with aggressive angiogenesis in resected NSCLC that was enhanced in the presence of high VEGF expression.     

Clonal analysis of human astrocytomas

Summary Clonal analysis of many human cancers have generally confirmed that they are monoclonal. Although astrocytic neoplasms are the most frequently occuring primary tumors in the central nervous system, their clonal composition has not been systematically studied. In this report, the clonal composition of 22 human astrocytomas of all histological grades (2 well-differentiated astrocytomas, 3 anaplastic astrocytomas and 17 glioblastoma multiforme) was determined by analysis of the pattern of X-chromosome inactivation. Leukocyte and non-tumor brain DNA were used as controls. In addition, specimens from different parts of four glioblastoma multiforme were analyzed to determine whether remote areas of the same tumor had the same clonal composition. Eighteen of nineteen informative astrocytomas had a monoclonal pattern of X-chromosome inactivation; one glioblastoma multiforme had loss of heterozygosity on the X chromosome. Specimens from different areas of the same tumor all had identical patterns of X-chromosome inactivation. Leukocytes and non-tumor brain used as controls uniformly had a polyclonal pattern of X-chromosome inactivation.Furthermore, loss of heterozygosity for chromosomes 10 or 17 p loci was found in 64% (9/14) of informative specimens and identical allelic patterns were observed in specimens from different areas of the same tumor.Our results demonstrate that human astrocytomas from low to high-grade are characterized by monoclonal cell populations. The presence of monoclonality in even low-grade neoplasms suggests that in astrocytic tumors the establishment of monoclonality occurs quite early. Also, the finding of a monoclonal pattern in intermediate- and high-grade astrocytomas further supports the hypothesis that clonal expansion underlies astrocytic tumor progression.     

VEGF和MMP-9在食管癌中的表达及低氧调节

目的 研究血管内皮生长因子（VEGF）和基质金属蛋白酶－9（MMP－9）的表达与食管癌血管形成和临床的关系,以及低氧对其的调节作用。方法 用逆转录－聚合酶链式反应（RT－PCR）检测了42例食管癌手术标本（包括18例癌旁组织）中VEGF和MMP－9mRNA的表达,用免疫组化染色的方法检测了56例食管癌标本中VEGF蛋白的表达和平均血管密度（MVD）,同时用酶联免疫吸附试验（ELISA）的方法定量测定了低氧对食管癌细胞系中VEGF和MMP－9表达的影响。结果 食管癌中VEGF的表达显著高于癌旁组织,与肿瘤内平均MVD密切正相关,VEGF表达和肿瘤中MVD计数与食管癌的分期、淋巴结转移密切相关。食管癌中MMP－9的表达也显著高于癌旁组织,但MMP－9的表达与食管癌中的MVD计数和临床病理特征无关。低氧可以显著增加食管癌细胞系中VEGF的表达,但对MMP－9的表达无明显影响。结果 VEGF的表达可能在食管癌血管形成和转移中起重要作用,并受低氧调节,有可能作为反映食管癌进展的生物学指标和抗血管治疗的靶点。     

Oncostatin M-induced genes in human astrocytomas

Oncostatin M (OSM) is a member of the interleukin-6 (IL-6) cytokine family and known to be induced in the nervous system as a result of cell stress. OSM is expressed in most human brain tumors, but the effects on tumor cells are unclear. The cytokine is known to activate the JAK/STAT signaling pathway by binding to its receptors gp130/OSMbeta or gp130/LIFRbeta and thereby initiating activation or suppression of a number of STAT target genes. The objective of the study was to identify OSM-regulated genes that could help in understanding the function of OSM in glioma cells. The glioma cell line, U1242MG was stimulated by OSM and the gene expression patterns were analyzed by microarray. In total, nineteen differentially expressed genes were selected due to high intensity, level of up/down-regulation and biological functions. The differentially expressed genes were verified using quantitative PCR. Additional validation of the confirmed OSM-induced proteins was performed in human astrocytoma tissues by immunohistochemistry. Among the up-regulated genes were CHI3L1, PLAU, MT2A and EPAS1. These genes are known to be involved in cell matrix remodeling, migration, proliferation control and angiogenesis. The results suggest that OSM induces genes that might contribute to the development and progression of astrocytomas.     

Expression of N-cadherin and alpha-catenin in astrocytomas and glioblastomas.

We examined levels of mRNA and protein for N-cadherin, the predominant cadherin in neural tissues, and mRNA levels for the cadherin-associated protein, alpha-catenin, in a series of gliomas and in glioblastoma cell lines. mRNA levels for N-cadherin and alpha-catenin were significantly higher in glioblastomas than in low-grade astrocytomas or normal brain, while the levels of intact N-cadherin protein were similar in glioblastomas, low-grade astrocytomas and brain. In addition, there was no consistent relationship between invasiveness and expression of N-cadherin and alpha-catenin in highly invasive vs minimally invasive tumours within the same histopathological grade. To assess further the relationship between cadherin expression and neural tumour invasion, we measured N-cadherin expression, calcium-dependent cell adhesion and motility of several glioblastoma cell lines. While all N-cadherin-expressing lines were adhesive, no correlation was seen between the level of N-cadherin expression and cell motility. Together, these findings imply that, in contrast to the role played by E-cadherin in carcinomas, N-cadherin does not restrict the invasion of glioblastomas.     

Genetic and hypoxic regulation of angiogenesis in gliomas

Infiltrative astrocytic neoplasms are by far the most common malignant brain tumors in adults. Clinically, they are highly problematic due to their widely invasive nature which makes a complete resection almost impossible. Biologic progression of these tumors is inevitable and adjuvant therapies are only moderately effective in prolonging survival. Glioblastoma multiforme (GBM WHO grade IV), the most malignant form of infiltrating astrocytoma, can evolve from a lower grade precursor tumor (secondary GBM) or can present as high grade lesion from the outset, so-called de novoGBM. Molecular genetic investigations suggest that GBMs are comprised of multiple molecular genetic subsets. Notwithstanding the diversity of genetic alterations leading to the GBM phenotype, the vascular changes that evolve in this disease, presumably favoring further growth, are remarkably similar. Underlying genetic alterations in GBM may tilt the balance in favor of an angiogenic phenotype by upregulation of pro-angiogenic factors and down-regulation of angiogenesis inhibitors. Increased vascularity and endothelial cell proliferation in GBMs are also driven by hypoxia-induced expression of pro-angiogenic cytokines, such vascular endothelial growth factor (VEGF). Understanding the contribution of genetic alterations and hypoxia in angiogenic dysregulation in astrocytic neoplasms will lead to the development of better anti-angiogenic therapies for this disease. This review will summarize the properties of angiogenic dysregulation that lead to the highly vascularized nature of these tumors.     

促血管生成素表达与人脑胶质瘤血管生成的关系研究

目的:研究促血管生成素(angiopoie-tins,Angs)蛋白表达水平与血管内皮生长因子(vascular endothelial growth factar,VEGF)和肿瘤内微血管密度(microvascular density,MVD)的关系,探讨其在人脑胶质瘤血管生成中的作用。方法:采用免疫组化方法检测42例人脑胶质瘤组织中Ang-1、Ang-2和VEGF的蛋白表达水平,并以抗CD34单克隆抗体显示血管内皮细胞,根据CD34阳性的血管计数来判定MVD。结果:42例人脑胶质瘤中,Ang-1+肿瘤的MVD比Ang-1-肿瘤高,但两者差异无统计学意义,P=0·156;Ang-2-和Ang-2+平均MVD分别是27·67和49·63,Ang-2+肿瘤MVD显著高于Ang-2-肿瘤,P=0·000。VEGF阳性表达时,Ang-2+肿瘤平均MVD显著高于Ang-2-肿瘤,分别为56·00和36·75,P=0·001;而VEGF阴性组中,Ang-2+肿瘤平均MVD与Ang-2-肿瘤几乎相等,分别为53·17和47·36,P=0·109。随胶质瘤恶性程度增加,Ang-1和Ang-2阳性表达率均升高,但Ang-2升高更明显,不同级别间Ang-2表达水平差异有统计学意义。结论:Ang-2高表达与人脑胶质瘤血管新生密切相关,Ang-2可以作为评价胶质瘤血管生成及恶性程度的一个重要指标。VEGF存在时,Ang-2过表达可促使肿瘤血管生成。肿瘤防治杂志,2005,12(19):1472-1475     

促血管生成素表达与人脑胶质瘤血管生成的关系研究

目的：研究促血管生成素（angiopoietins,Angs）蛋白表达水平与血管内皮生长因子（vascular endotheljal growth factar,VEGF）和肿瘤内微血管密度（microvascular density,MVD）的关系,探讨其在人脑胶质瘤血管生成中的作用.方法：采用免疫组化方法检测42例人脑胶质瘤组织中Ang-1、Ang 2和VEGF的蛋白表达水平,并以抗CD34单克隆抗体显示血管内皮细胞,根据CD34阳性的血管计数来判定MVD.结果：42例人脑胶质瘤中,Ang 1＋肿瘤的MVD比Ang-1-肿瘤高,但两者差异无统计学意义,P=0.156;Ang-2和Ang-2^＋平均MVD分别是27.67和49.63,Ang-2^＋肿瘤MVD显著高于Ang-2肿瘤,P=0.000.VEGF阳性表达时,Ang-2^＋肿瘤平均MVD显著高于Ang 2肿瘤,分别为56.00和36.75,P=0.001;而VEGF阴性组中,Ang-2^＋肿瘤平均MVD与Ang-2^-肿瘤几乎相等,分别为53.17和47.36,P=0.109.随胶质瘤恶性程度增加,Ang-1和Ang-2阳性表达率均升高,但Ang-2升高更明显,不同级别间Ang-2表达水平差异有统计学意义.结论：Ang-2高表达与人脑胶质瘤血管新生密切相关,Ang-2可以作为评价胶质瘤血管生成及恶性程度的一个重要指标.VEGF存在时,Ang-2过表达可促使肿瘤血管生成.