Endoglin：肿瘤新生血管的标志物

Endoglin为细胞膜糖蛋白 ,能调节细胞对转化生长因子 β的反应 ,在血管生成的组织和肿瘤组织的血管内皮细胞中肿瘤组织边缘部分血管起源性内皮细胞高度表达。Endoglin的表达与某些肿瘤的预后密切相关 ,可能成为肿瘤的预后指标。应用免疫治疗、基因反义技术阻断肿瘤组织中尚未形成血管的内皮细胞合成Endoglin ,可抑制肿瘤组织微血管的生成 ,阻断肿瘤浸润转移途径 ,将在肿瘤治疗中显示出良好的前景。     

RNA干扰沉默神经轴突导向因子受体4基因增加血肿瘤屏障通透性

目的研究神经轴突导向因子受体(Robo4)对血肿瘤屏障(BTB)通透性的影响。方法建立了体外BTB模型,应用Real-time PCR和Western blot检测Robo4在正常人脑微血管内皮细胞和胶质瘤微血管内皮细胞中的表达变化。设计合成针对Robo4基因的小干扰RNA,转染至人脑微血管内皮h CMEC/D3细胞,下调体外血肿瘤屏障模型内皮细胞中Robo4的表达,跨内皮电阻测量系统和辣根过氧化物酶渗透试验分析血肿瘤屏障通透性变化;Western blot和免疫荧光法检测h CMEC/D3细胞中紧密连接相关蛋白occludin和ZO-1的表达和分布变化。结果和正常人脑微血管内皮细胞相比,Robo4在胶质瘤微血管内皮细胞中的表达显著上调。下调体外血肿瘤屏障模型内皮细胞Robo4的表达后,TEER值显著降低,辣根过氧化物酶透过率显著增高;同时胶质瘤微血管内皮细胞中紧密连接相关蛋白occludin和ZO-1的表达显著降低,在细胞膜上呈不连续分布。结论 RNA干扰沉默Robo4表达能够显著降低紧密连接相关蛋白occludin和ZO-1的表达,增加BTB通透性。     

骨肉瘤组织survivin与 VEGF的表达及相关性

凋亡抑制蛋白（inhibitor of apoptosis protein,IAP）是抑制细胞凋亡的重要成分,survivin是最近发现的一种IAP家族成员,其在成人正常组织中不表达而选择性表达于恶性肿瘤组织的特性,使抗细胞凋亡与肿瘤发生的关系更为接近。血管内皮细胞生长因子（vascular endothelium growth factor,VEGF）是已知肿瘤血管生成中最重要的诱发因子,     

血管内皮细胞增殖标志物CD105的研究进展

CD105是一种内皮细胞增殖的标志物,是转化生长因子 β(TGF β)受体复合物的成分之一。CD105在增殖的内皮细胞和血管生成旺盛的肿瘤组织内新生血管内皮细胞中呈过表达,而在正常成熟组织的血管内皮细胞中表达弱或不表达。具有调节内皮细胞对TGF的反应、促内皮细胞增殖和促血管形成等功能,可用来诊断肿瘤、预测疗效,也可用来抗肿瘤血管治疗。     

MCP-1/CCR2信号途径介导酒精诱导的乳腺癌血管新生

目的:研究单核细胞趋化蛋白1(MCP-1)及其受体CC趋化因子受体2(CCR2)在酒精刺激乳腺癌血管生成中的作用及其机制。方法:建立小鼠饮酒乳腺癌移植瘤模型,免疫组化检测肿瘤组织中MCP-1和CCR2表达与血管标志物血小板内皮细胞黏附分子1(PECAM-1)和血管内皮生长因子(VEGF)表达的相关性。体外建立3D肿瘤-内皮细胞共培养系统观察肿瘤血管新生,检测MCP-1/CCR2信号在酒精介导血管生成中的作用。通过细胞迁移实验检测MCP-1/CCR2是否增加细胞移动而促进脉管形成。结果:饮酒的荷瘤小鼠肿瘤组织中MCP-1和CCR2均高表达,且表达水平和血管新生标志物PECAM-1和VEGF相一致。通过3D肿瘤-内皮细胞共培养系统观察到小鼠乳腺癌E0771细胞和内皮细胞相互作用可促进血管的形成,酒精可以增强此种肿瘤血管新生效应。外源性MCP-1可以促进此种肿瘤血管生成,其受体CCR2抑制剂处理则可以有效抑制酒精刺激的肿瘤血管生成。进一步研究发现MCP-1/CCR2可以增强内皮细胞的迁移能力。结论:MCP-1/CCR2信号途径在酒精刺激乳腺癌血管生成中发挥重要作用,其机制可能是促进了内皮细胞的迁移从而加速了肿瘤脉管新生。     

EGFL7在乳腺癌中的研究进展

表皮生长因子样结构域7是表皮生长因子样蛋白家族的成员,是一种极为关键的血管生成因子和血管发育调节因子,在不同类型细胞中均有表达。EGFL7在早期胚胎的血管中表达较高,主要调节发育过程中的血管生成,促进内皮细胞增殖,形成有功能的血管网,促进组织增长和再生。与其在胚胎期较强的表达相比,在成人体内的表达量微乎其微,异常高表达的EGFL7常在多种恶性肿瘤中出现。目前越来越多的证据表明,EGFL7可调节肿瘤血管生成、促进肿瘤转移和侵袭。肿瘤组织中EGFL7高表达常常提示肿瘤生长和转移较为活跃及不良的预后。近年来,一系列研究表明,EGFL7的表达与乳腺癌的发生发展、转移过程密不可分,且在提示预后方面发挥着关键作用。本文就EGFL7在乳腺癌中的研究进展作一综述,为临床诊断及治疗提供新思路。     

人星形细胞瘤中单核细胞在血管生成过程中的作用

目的探讨单核细胞在人星形细胞瘤血管生成(Angiogenesis)过程中的作用.方法应用硷性纤维母细胞生长因于(bFGF)的抗体,通过免疫组织化学手段,在组织学切片上探讨单核细胞和bFGF在人星形细胞瘤血管生成过程中的作用.结果1.bFGF在血管内皮细胞中的表达强度随血管密度增加而增加,并与血管密度之间存在回归直线,P＜0.01.2.28.3%的切片中单核细胞表达bFGF,表达bFGF的单核细胞可见于血管内,或沿血管壁呈规则排列,也可成堆靠近血管壁,并使血管呈出芽生长.结论肿瘤内新生的血管内皮细胞可产生bFGF;单核细胞不但产生bFGF,而且参与肿瘤内的血管生成,它可能是血管内皮细胞的前期细胞.     

Vasohibin-1在常见肿瘤发生发展中作用的研究进展

肿瘤的形成、生长和侵袭转移依赖于肿瘤血管的生成。抑制肿瘤血管形成是阻止肿瘤进展的重要途径。肿瘤血管的生长受多种促进因子(如血管内皮生长因子、碱性成纤维细胞生长因子、胸苷磷酸化酶等)和抑制因子(如血管抑素、内皮抑素、血管生成抑制蛋白等)的共同调节。Vasohibin-1(VASH-1)作为一种新型血管抑制因子,受VEGF诱导表达于内皮细胞,发挥负性调控作用。近年来越来越多的研究发现VASH-1在多种肿瘤组织中异常表达并发挥作用。该文旨在对VASH-1在一些常见肿瘤发生、发展中的作用及机制作一综述。     

血管生成素及其受体与肿瘤的血管生成

血管生成素 (Ang)家族是唯一含受体激动剂及抑制剂的促血管生成因子 ,编码四种结构相似的蛋白质 ,包括Ang 1,Ang 2 ,Ang 3和Ang 4 ,均能与内皮细胞上的酪氨酸激酶受体Tie 2结合 ,参与生理性及病理性的血管生成。Ang 1激活Tie 2 ,促进血管生成 ,维持血管稳定 ;Ang 2的作用呈VEGF依赖性 ,VEGF存在时 ,可促进血管出芽 ,VEGF缺乏时 ,则促进血管退化。Ang家族在不同的肿瘤中表达水平及分布形式不一。应用sTie 2或以Ang家族为靶标可抑制肿瘤性血管生成 ,对肿瘤的治疗有潜在的应用前景。     

表达Tie2基因的单核细胞研究进展

肿瘤血管的生成和发展在肿瘤的生长和恶化过程中起着关键作用。一类表达Tie2基因的单核细胞（TEM）通过一些生长因子和化学信号被募集到肿瘤组织中,旁分泌细胞因子促进肿瘤血管的生成和发展。TEM在促进肿瘤血管形成中起着重要作用,与血管内皮细胞祖细胞（EPC）不同的是,TEM只是在肿瘤的血管生成中起促进作用,但在肿瘤周围临近的正常组织中没有发现其存在,TEM被认为是一类肿瘤组织特异性的细胞。以TEM为载体细胞,通过TEM表达抗肿瘤药物,靶向递送的抗肿瘤药物能够有效的抑制肿瘤的生长和恶化。     

Roundabout 4 is expressed on hematopoietic stem cells and potentially involved in the niche-mediated regulation of the side population phenotype

Roundabout (Robo) family proteins are immunoglobulin-type cell surface receptors that are expressed predominantly in the nervous system. The fourth member of this family, Robo4, is distinct from the other family members in that it is expressed specifically in endothelial cells. In this study, we examined the expression of Robo4 in hematopoietic stem cells (HSCs) and its possible role in HSC regulation. Robo4 mRNA was specifically expressed in murine HSCs and the immature progenitor cell fraction but not in lineage-positive cells or differentiated progenitors. Moreover, flow cytometry showed a correlation between higher expression of Robo4 and immature phenotypes of hematopoietic cells. Robo4(high) hematopoietic stem/progenitor cells presented higher clonogenic activity or long-term repopulating activity by colony assays or transplantation assays, respectively. A ligand for Robo4, Slit2, is specifically expressed in bone marrow stromal cells, and its expression was induced in osteoblasts in response to myelosuppressive stress. Interestingly, overexpression of Robo4 or Slit2 in HSCs resulted in their decreased residence in the c-Kit(+)Sca-1(+)Lineage(-)-side population fraction. These results indicate that Robo4 is expressed in HSCs, and Robo4/Slit2 signaling may play a role in HSC homeostasis in the bone marrow niche.     

Cell-surface heparan sulfate is involved in the repulsive guidance activities of Slit2 protein.

Slit proteins are a family of secreted guidance proteins that can repel neuronal migration and axon growth via interaction with their cellular roundabout receptors (Robos). Here it was shown that Slit2-Robo-1 interactions were enhanced by cell-surface heparan sulfate. Removal of heparan sulfate decreased the affinity of Slit for Robo by about threefold. In addition, removal of cell-surface heparan sulfate by heparinase III abolished the chemorepulsive response to Slit2 normally shown by both the migrating neurons and growing axons. These results indicate essential roles for cell-surface heparan sulfate in the repulsive activities of Slit2.     

用RNA-RNA原位杂交技术研究Robo2在早期鸡胚发育中的表达

目的:探讨Robo2(roundabout homolog 2)在早期鸡胚发育中的表达。方法:利用分子生物学手段,构建Robo2/pSPT18重组质粒,并且制备地高辛标记的Robo2 RNA探针,进而通过RNA-RNA原位杂交技术检测Robo2在早期鸡胚发育中的表达。结果:原条发生前Robo2表达较弱,原条发生后主要表达在原条和神经板。体节期Robo2主要表达在脊索、神经管、体节和血岛部位。冰冻切片后观察到Robo2主要表达在外胚层,而在中胚层和内胚层只有部分表达。结论:阐明了Robo2在早期鸡胚发育中的表达,为进一步研究Robo2在正常生理和病理条件下的功能及作用机制奠定基础。     

Robo family of proteins exhibit differential expression in mouse spinal cord and Robo-Slit interaction is required for midline crossing in vertebrate spinal cord.

The ventral midline of the central nervous system is an important intermediate target where growing commissural axons either cross and project contralaterally or remain on the same side of the body. New studies on mice and humans show that this decision by commissural axons is largely dependent on Slits, extracellular matrix proteins that are widely expressed in the midline of the nervous system, and their receptors, Robos (Long et al. [2004] Neuron 42:213-223; Sabatier et al. [2004] Cell 117:157-169; Jen et al. [2004] Science 304:1509-1513). Here, we show that the Robo family proteins Robo1 and Rig-1 exhibit differential expression patterns on commissural axons as they approach, cross, and leave the midline of the developing mouse spinal cord and demonstrate that Robo1 and Robo2 bind Slit1 and Slit2, but Rig-1 does not. In addition, we show that cultured chick commissural axons are repelled by a source of Slit protein, and the soluble Robo-Fc proteins are capable of neutralizing this repulsion. Finally, we exploit the large size and accessibility of the early chick embryo to analyze the function of Slit/Robo signaling in midline commissural axon guidance, and we demonstrate that the in vivo perturbation of Robo-Slit interaction at the floor plate causes consistent guidance defects of commissural axons during midline crossing. These findings demonstrate the evolutionarily conserved role for Robo-Slit interaction in the control of midline crossing axons in vertebrates.     

Control of human hematopoietic stem/progenitor cell migration by the extracellular matrix protein Slit3

Patients whose hematopoietic system is compromised by chemo- and/or radiotherapy require transplantation of hematopoietic stem and progenitor cells (HSPCs) to restore hematopoiesis. Successful homing of transplanted HSPCs to the bone marrow (BM) largely depends on their migratory potential, which is critically regulated by the chemokine CXCL12. In this study, we have investigated the expression and function of Slit proteins and their corresponding Roundabout (Robo) receptors in human HSPC migration. Slit proteins are extracellular matrix proteins that can modulate the (chemoattractant-induced) migration of mature leukocytes. We show that mRNAs for all Slits (Slit1-3) are expressed in primary BM stroma and BM-derived endothelial and stromal cell lines, but not in CD34? HSPCs. Human CD34? HSPCs expressed mRNAs for all Robos (Robo1-4), but only the Robo1 protein was detected on their cell surface. Functionally, Slit3 treatment increased the in vivo homing efficiency of CD34? HSPCs to the BM in NOD/SCID mice, whereas Slit3-exposed HSPC migration in vitro was inhibited. These effects do not appear to result from modulated CXCL12 responsiveness as CXCR4 expression, CXCL12-induced actin polymerization or the basal and CXCL12-induced adhesion to fibronectin or BM-derived endothelial cells of CD34? HSPC were not altered by Slit3 exposure. However, we show that Slit3 rapidly reduced the levels of active RhoA in HL60 cells and primary CD34? HSPC, directly affecting a pathway involved in actin cytoskeleton remodeling and HSPC migration. Together, our results support a role for Slit3 in human HSPC migration in vitro and homing in vivo and might contribute to the design of future approaches aimed at improving transplantation efficiency of human CD34? HSPCs.     

Expression of Robo protein in bladder cancer tissues and its effect on the growth of cancer cells by blocking Robo protein

This study aimed to detect the expression of Slit signaling protein ligand Robo protein in human bladder cancer and para-carcinoma tissue, and observe the tumor cell survival and growth by inoculating the bladder cancer cells with the blocked signaling protein into the subcutaneous tissue of nude mice. The expression of Robo protein was detected in T24 cells in human bladder uroepithelium carcinoma and cultivated human bladder uroepithelium carcinoma confirmed by pathological diagnosis. The cultivated T24 cells were coated by the protein antibody and human bladder uroepithelium carcinoma T24 tumor-bearing mice model was established. The tumor cell survival and growth were observed in the antibody coating group and non-coating group. The tumor body size was measured. The immunohistochemical detection showed that Robo protein isoforms Robo1 and Robo 4 were expressed in T24 cells of cancer tissues, paracarcinoma tissues and cultured human uroepithelium carcinoma. The expression of Robo1 was significantly higher than that of Robo4 (P<0.05). The cancer cells could be detected in nodular tumor of mice in each group. The volume of the tumor-bearing mice in the nodular tumor of the non-coating group was larger than that of anti-Robol antibody coating group and the difference was statistically significant (P<0.01). There was no significant difference in tumor volume between anti-Robo4 antibody coating group and non-coating group (P>0.05); The difference was statistically significant compared with the anti-Robo1 antibody coating group (P<0.01). In conclusion, Robo protein isoforms Robo1 and Robo4 were expressed in human bladder cancer T24 cells. To block Robo4 signal protein had little effect on the survival and growth of the transplantation tumor and to block Robo1 signal protein would seriously affect the survival and growth of the transplantation tumor, suggesting that Robo1 might play an important role in the growth and metastasis of bladder cancer, and might become a new target for the treatment of human bladder cancer and drug research.     

Semaphorins与肿瘤的发生和转移

Semaphorins是一大类具有保守Sema结构域的信号蛋白。该家族分为8个亚群,目前已发现30多个成员,有分泌型、跨膜型和GPI锚定3种类型。在病毒、非脊椎动物和脊椎动物中都已发现Semaphorins分子的存在。该家族蛋白主要有2种受体：plexins和neuropilins,它们对Semaphorins功能的发挥非常重要。Semaphorins首先是作为神经系统中一种重要的神经导向分子而被发现和认识的。起初的研究多围绕其在神经系统轴突导向中所发挥的作用而进行,发现Semaphorins分子可以抑制或促进轴突的生长。但现在越来越多的研究表明,除了在神经系统中具有重要作用外,Semaphorins分子在肿瘤生长、血管内皮细胞迁移、免疫反应等方面也有重要的生物学功能。Semaphorins分子通过促进或抑制肿瘤血管发生而对肿瘤的发生发展进行调节。     

Implication of HARP in angiogenesis and possible therapeutic role]

HARP (heparin affin regulatory peptide), also called pleiotrophin (PTN), belongs to the heparin binding growth factors (HBGFs) family. Several new data suggest a role for HARP during the various stages of angiogenesis. In vivo, HARP is localised in endothelial cells of blood capillaries. In vitro, HARP displays mitogenic activity on endothelial cells, induces the formation of capillary-like structures in collagen gel, and degrades extracellular matrix via stimulation of plasminogen activator activity. HARP is also involved in neoangiogenesis during tumor progression. This review discusses the possible role of HARP in tumor angiogenesis and its therapeutic implications.