内皮抑素对HepG-2细胞生长的影响及机制研究

目的探讨内皮抑素对人肝癌细胞株HepG-2细胞生长增殖和血管内皮生长因子（VEGF）基因表达的影响及其可能的机制，为临床肝癌治疗中内皮抑素的应用提供实验依据。方法采用MTT法检测不同浓度的内皮抑素作用不同时间后对HepG-2细胞生长的抑制作用；流式细胞仪检测内皮抑素对细胞凋亡及周期分布的影响；免疫组织化学法检测内皮抑素作用前后HepG-2细胞中survivin蛋白表达的改变；Western blotting法检测加药前后HepG-2细胞中VEGF蛋白表达的变化。结果内皮抑素能抑制HepG-2细胞的生长增殖（P〈0．05），呈剂量-时间依赖性，并诱导细胞凋亡；免疫组织化学结果显示，内皮抑素作用后HepG-2细胞中survivin蛋白表达明显减少，差异具有显著性（P〈0．01）；Westernblotting结果显示药物作用组中VEGF蛋白表达明显减少，差异具有显著性（P〈0．01）。结论内皮抑素通过下调survivin蛋白的表达诱导HepG-2细胞的凋亡、抑制增殖，并能明显降低HepG-2细胞中VEGF的表达。     

内皮抑素对人卵巢癌细胞系生长的抑制作用

目的探讨人内皮抑素对人卵巢癌SKOV3细胞生长的抑制作用及其作用机制。方法MTT法检测细胞生长;透射电镜观察细胞凋亡;免疫细胞化学、RT-PCR及Western blot法检测细胞中BCL-2和BAX蛋白及mRNA的表达。结果内皮抑素抑制SKOV3细胞增殖(P<0.01);能诱导SKOV3细胞凋亡;而对细胞中BCL-2和BAX蛋白及mRNA的表达无明显影响。结论人内皮抑素具有抑制卵巢癌细胞SKOV3生长的作用,其作用机制可能与诱发细胞凋亡相关。     

腺苷抑制脂多糖诱导的人脐静脉内皮细胞凋亡

目的 探讨腺苷抑制脂多糖（LPS）诱导人脐静脉内皮细胞（HUVEC）的凋亡。方法 将培养的HUVEC分成6组：对照组,二甲基亚砜（DMSO）组,LPS组,低、中和高剂量腺苷组,用荧光显微镜动态观察细胞形态结构,用ELISA检测上清液中TNF-α表达量,用流式细胞技术检测各组细胞凋亡。结果 LPS组细胞凋亡率显著升高,TNF-α的表达量也显著升高（p＜0.05）;不同剂量腺苷能显著抑制LPS诱导的TNF-α的表达,显著抑制细胞的凋亡率（p＜0.05）。结论 一定浓度的腺苷能抑制LPS 诱导的HUVEC释放炎症介质、抑制细胞发生凋亡。     

肿瘤抑素41肽重组表达及活性研究

目的：构建肿瘤抑素41肽重组质粒,使其高效表达并纯化得到41肽,研究其抗肿瘤活性。方法人工设计并合成肿瘤抑素41肽基因序列,克隆到表达载体 pTYB21上,转化到大肠埃希菌 BL?21（DE3）中, IPTG诱导融合蛋白高效表达,几丁质亲和层析柱纯化后经Tricine?SDS?PAGE鉴定41肽。利用MTT法、吖啶橙／溴化乙锭（ AO／EB）荧光染色、小鼠H22腹水型转移型肝癌实体瘤模型抑瘤实验并结合组织病理切片来研究肿瘤抑素41肽的生物学活性。结果构建肿瘤抑素41肽重组质粒,获得可溶性肿瘤抑素41肽。体外实验显示,41肽具有抑制人脐静脉内皮 HUVEC 细胞、人胃癌 HGC?27细胞和人肝癌HepG2细胞增殖和促进HUVEC、 HGC?27细胞凋亡的作用。体内实验显示,41肽对小鼠H22腹水型转移肝癌实体瘤生长具有明显的抑制作用,抑瘤率达到34?35％。结论成功构建了pTYB21?41肽重组质粒,肿瘤抑素41肽具有显著的抗肿瘤活性,为肿瘤抑素机制研究和临床应用研究奠定了基础。     

内皮抑素对肝癌HepG-2细胞生长和血管内皮生长因子表达的影响

目的:探讨内皮抑素对人肝癌细胞株HepG-2细胞生长和血管内皮生长因子(VEGF)表达的影响及其可能的机制.方法:采用MTT法检测不同浓度的内皮抑素作用不同时间后对HepG-2细胞生长的抑制作用;电镜观察加药前后HepG-2细胞超微结构的变化;免疫组织化学法检测内皮抑素作用前后HepG-2细胞中存活素表达的改变;RT-PCR法检测加药前后HepG-2细胞中VEGF基因表达的变化.结果:内皮抑素能抑制HepG-2细胞的生长增殖,呈剂量-时间依赖性,并诱导细胞凋亡;内皮抑素作用后HepG-2细胞中存活素表达明显减少,VEGF表达明显减少.结论:内皮抑素通过下调存活素的表达,诱导HepG-2细胞的凋亡、抑制其增殖,并能显著降低HepG-2细胞中VEGF的表达.     

重组人血管内皮抑素对人多发性骨髓瘤细胞RPMI 8226增殖和相关蛋白表达的影响

 目的： 研究重组人血管内皮抑素（恩度）在体外对人多发性骨髓瘤细胞株RPMI 8226细胞增殖、细胞周期及细胞相关蛋白表达的影响。方法： 用CCK-8检测恩度对RPMI 8226细胞增殖的影响;流式细胞术检测凋亡和细胞周期的改变;Western blotting检测凋亡相关蛋白Bcl-2和caspase-3表达变化;以实时定量PCR和Western blotting检测RPMI 8226细胞血管细胞粘附因子 1（VCAM-1）、白细胞介素 6（IL-6）和血管内皮生长因子（VEGF）mRNA以及蛋白表达变化;ELISA检测细胞上清液中细胞因子IL-6和VEGF水平。结果： 恩度对RPMI 8226细胞有增殖抑制作用,250 mg/L恩度对RPMI 8226细胞 72 h增殖抑制率为（59.5±5.6）%（P<0.05）,细胞G1期比例增加（P<0.05）,但对细胞凋亡及凋亡相关蛋白Bcl-2和caspase-3表达无显著影响;经恩度作用后RPMI 8226细胞 VCAM-1表达下降（P<0.05）,IL-6和VEGF表达及分泌降低（均P<0.05）。结论： 恩度能通过改变细胞周期变化抑制RPMI 8226细胞增殖,并能减少VCAM-1表达及IL-6、VEGF分泌,对细胞凋亡无明显改变。     

恒磁场对内皮细胞凋亡、黏附分子表达及其与单核细胞黏附率的影响

目的： 初步观察恒磁场对血管紧张素Ⅱ(AngⅡ)作用下人脐静脉内皮细胞(HUVEC) 凋亡、细胞间黏附分子-1(ICAM-1)和血管细胞粘附分子-1（VCAM-1）的分泌与表达及HUVEC与人单核细胞株THP-1黏附率的影响。方法： 采用体外培养第3代的HUVEC，实验分为6组：对照组、AngⅡ（10^-6 mol/L）组及AngⅡ+不同磁感应强度（1 Gs、5 Gs、10 Gs、20 Gs）的恒磁场组。各组细胞于单纯培养或磁场作用24 h后收集样品，用末端脱氧核糖核酸酶介导的dUTP末端标记法 (TUNEL)和流式细胞仪碘化丙锭染色法检测细胞凋亡，酶联免疫吸附试验（ELISA）检测培养液中ICAM-1、VCAM-1的含量，免疫细胞化学检测ICAM-1、VCAM-1的蛋白表达，计数法观察HUVEC与THP-1的黏附率。 结果： AngⅡ10-6 mol/L可诱导HUVEC凋亡（P<0.05 vs 对照组），而1 Gs、5 Gs、10 Gs和20 Gs恒磁场组细胞凋亡率显著低于AngⅡ组（P<0.05）。AngⅡ(10^-6 mol/L)组HUVEC的ICAM-1和VCAM-1含量和表达量显著高于对照组（P<0.05），而1 Gs、5 Gs、10 Gs和20 Gs恒磁场组细胞ICAM-1的含量和表达量显著低于AngⅡ组（P<0.05）。AngⅡ (10^-6 mol/L)组HUVEC与THP-1的黏附率显著高于对照组（P<0.05），而1 Gs、5 Gs、10 Gs和20 Gs恒磁场组HUVEC与THP-1的黏附率显著低于AngⅡ组（P<0.05）。 结论： 恒磁场可拮抗AngⅡ的作用，抑制HUVEC凋亡、HUVEC的ICAM-1和VCAM-1分泌与表达及HUVEC与单核细胞的黏附率。     

小檗碱对人脐静脉内皮细胞增殖与凋亡的作用

目的：观察小檗碱对人脐静脉内皮细胞增殖与凋亡的作用，以探讨小檗碱抑制肿瘤生长与转移的机制。 方法： 用小檗碱与体外培养的人脐静脉内皮细胞（HUVEC）共同孵育，以MTT法检测细胞的增殖活性，免疫细胞化学法检测增殖细胞核抗原（PCNA）的表达，荧光染色法观察凋亡细胞核形态，用Rhodamine123染色，激光共聚焦显微镜检测线粒体膜电位。 结果： 不同浓度小檗碱与HUVEC共同孵育可明显抑制HUVEC的增殖(P<0.05，P<0.01)，呈现一定的浓度依赖性和时效性；20 mg/L小檗碱与HUVEC共同孵育48 h，可显著降低细胞核PCNA的表达（P<0.01），并可见凋亡细胞数增多、线粒体膜电位明显降低（P<0.01）。 结论： 小檗碱抑制血管内皮细胞的增殖，并促进血管内皮细胞凋亡，从而抑制肿瘤血管形成，可能是小檗碱抑制肿瘤生长与转移的机制之一。     

PTEN抑制剂对软脂酸引起脐静脉内皮细胞凋亡的保护作用

目的 探讨抑癌基因PTEN（phosphatase and tensin homology deleted on chromosome ten）的抑制剂双过氧钒（bpV）对软脂酸（PA）引起人脐静脉内皮细胞（HUVEC）凋亡的保护作用。方法 四甲基偶氮唑盐(MTT)测定细胞生存率;Hoechst-PI染色荧光显微镜观测细胞凋亡形态;Annexin-Ⅴ-PI流式细胞术测定细胞凋亡,Western blotting检测总PTEN和磷酸化PTEN蛋白水平,实时定量PCR测定细胞PTEN mRNA的表达。 结果 MTT显示,PA（0.2~0.6mmol/L）作用24h后可明显抑制HUVEC细胞的生长;Hoechst-PI染色荧光显微镜及Annexin-Ⅴ-PI双染流式细胞检测证实不同浓度的PA处理24h后,随着PA浓度(0.2~0.6mmol/L)的增高,其诱导HUVEC细胞的凋亡作用增强,实时定量PCR 及Western blotting显示,PA浓度(0.2~0.6mmol/L)作用细胞后PTEN的转录及活性随浓度增高而增加,并呈现一定的剂量依赖性。bpV作用细胞可以增加细胞的生存率,抑制细胞的凋亡,PTEN的转录及蛋白表达降低。结论 一定浓度范围内PA剂量依赖性诱导HUVEC细胞发生凋亡性损伤,在此过程中伴随细胞内PTEN表达上调和活性增强,PTEN抑制剂双过氧钒使细胞的凋亡作用减轻,在此过程中PTEN转录及蛋白表达降低,PTEN信号通路可能是PA诱导脐静脉内皮细胞凋亡的重要通路之一, PTEN抑制剂可抑制此通路起到对细胞的保护作用。     

登革病毒感染对血管内皮细胞ICAM-1表达的影响

目的探讨登革病毒2型（DV2）体外感染对人脐静脉内皮细胞（HUVEC）表达细胞间黏附分子（intercellular adhesion molecule，ICAM-1）的影响。方法原代分离培养HUVEC，用生长良好的2、3代细胞进行实验。用CCK-8法测定DV2感染前后的细胞活性。流式细胞仪测定DV2感染组和对照组细胞在不同实验时间点细胞表面ICAM-1蛋白表达的情况。采用逆转录聚合酶链反应（RT-PCR）法和图像定量分析技术分析DV2感染组和对照组在不同实验时间点HUVEC内ICAM-1 mRNA水平。结果病毒感染HUVEC对细胞活力的影响与对照组相比差异无统计学意义。DV2感染HUVEC促进ICAM-1 mRNA转录，DV2组与对照组相比差异有统计学意义（P〈0．05）。其中，正常状态下HUVEC有一定水平ICAM-1 mRNA转录，但感染后显著增加（P〈0．05），24—72h维持于高水平，与其他时间表达差异有统计学意义（P〈0．05）。DV2感染HUVEC，细胞表达ICAM-1蛋白在12～72h显著升高，与对照组相比差异有统计学意义（P〈0．05）。结论DV2感染上调HUVEC的ICAM-1 mRNA水平和蛋白表达，从而诱发并加重血管内皮局部的损伤，破坏血管的屏障功能，促进血管渗漏的形成与发展。这可能是DV2感染诱发患者血管通透性升高和血浆渗漏的重要分子机制之一。     

High serum endostatin levels in Down syndrome: implications for improved treatment and prevention of solid tumours.

We report here a comparison of serum endostatin levels in Down syndrome patients to normal control subjects. We analysed serum samples from 35 patients with Down syndrome and 54 normal control subjects and found that although serum levels of endostatin vary widely in a normal human population, serum endostatin levels are significantly elevated in patients with Down syndrome. This result may explain the relative decrease in incidence of various solid tissue tumours observed in Down syndrome, given the role of endostatin as a potent inhibitor of tumour-induced angiogenesis in both human and animal models. Based upon these data, we propose that an increase of about one-third of normal endostatin serum levels may represent an effective therapeutic dose to significantly inhibit many solid tumours.     

Non-heparan sulfate-binding interactions of endostatin/collagen XVIII in murine development.

Knobloch syndrome is characterized by a congenital generalized eye disease and cranial defect. Pathogenic mutations preferentially lead to a deletion or functional alteration of collagen XVIII's most C-terminal endostatin domain. Endostatin can be released from collagen XVIII and is a potent inhibitor of angiogenesis and tumor growth. We show differential expression of binding partners for endostatin, vascular endothelial growth factor (VEGF), and the collagen XV endostatin homologue in murine embryonal development using a set of alkaline phosphatase fusion proteins. Consistent with the human phenotype, vascular mesenchyme in the developing eye was identified as endostatin's primary target. While endostatin predominantly bound to blood vessels, the VEGF164 affinity probe labeled nonvascular tissues such as forebrain, hindbrain, the optic nerve, and the surface ectoderm of the future cornea. Strikingly increased staining specificity was observed with a non-heparin/heparan sulfate-binding endostatin probe. In contrast, elimination of the heparan sulfate binding site from VEGF led to complete loss of binding. The collagen XV endostatin homologue showed a highly restricted binding pattern. Oligomerization with endogenous endostatin was ruled out by use of collagen XVIII knockout mice. Our data provide strong evidence that collagen XVIII's C-terminal endostatin domain harbors a prominent tissue-binding site and that binding can occur in the absence of heparan sulfates in situ.     

Imbalance between vascular endothelial growth factor and endostatin levels in induced sputum from asthmatic subjects

BACKGROUND: Angiogenesis has recently attracted considerable attention as a component of airway remodeling in bronchial asthma. Vascular endothelial growth factor (VEGF) is highly expressed in asthmatic airways, and its contribution to airway remodeling has been reported. Although angiogenesis is regulated by a balance of angiogenic and antiangiogenic factors, the relative levels of antiangiogenic factors in asthmatic airways have not been evaluated. OBJECTIVE: We sought to determine whether an imbalance between angiogenic and antiangiogenic factors exists in asthmatic airways. METHODS: We simultaneously measured VEGF and endostatin levels and evaluated their correlation and balance in induced sputum from 18 steroid-naive asthmatic subjects and 11 healthy control subjects. After initial sputum induction, asthmatic subjects underwent 8 weeks of inhaled beclomethasone dipropionate (BDP; 800 microg/d) therapy, and sputum induction was then repeated. RESULTS: VEGF and endostatin levels in induced sputum were significantly higher in asthmatic subjects than in control subjects (P <.001). There was a significant correlation between VEGF and endostatin levels in both control subjects (r = 0.995, P <.001) and asthmatic subjects (r = 0.923, P <.001). Moreover, the VEGF/endostatin level ratio in asthmatic subjects was significantly higher than that in control subjects (P <.0001). After 8 weeks of inhaled BDP therapy, the VEGF level in induced sputum in asthmatic subjects was significantly decreased (P <.001), whereas the endostatin level was not. A correlation between VEGF and endostatin levels existed even after BDP therapy (r = 0.861, P <.001). Moreover, the VEGF/endostatin level ratio was significantly decreased to the same level as in the control subjects after BDP therapy (P <.0001). CONCLUSION: There was an imbalance between VEGF and endostatin levels in induced sputum from asthmatic subjects. This imbalance might play an important role in the pathogenesis of bronchial asthma through its effects on angiogenesis.     

心肌梗死大鼠缺血心肌中内皮抑素的表达

目的： 观察心肌梗死后大鼠不同时间缺血心肌中内皮抑素的表达及其与新生血管密度和血管内皮生长因子（VEGF）的关系。 方法： 32只心肌梗死SD大鼠随机分为心肌梗死后7、14、21、28 d 4个组，以假手术组作为正常对照组，每组8只。应用免疫组织化学染色方法，观察各组心肌梗死大鼠缺血心肌中内皮抑素、VEGF 的表达和新生血管密度。 结果： 心肌梗死大鼠缺血心肌中内皮抑素的表达明显增加，弥散分部于心肌细胞和组织间隙，第7 d表达量最高，至14、21、28 d表达量逐渐降低，28 d基本降至基础水平，与VEGF表达的变化趋势一致，并与新生血管密度相关。 结论： 内皮抑素在心肌梗死大鼠的缺血心肌中表达增加，与VEGF的动态变化一致，并与新生血管密度呈正相关，提示内皮抑素可能参与缺血心肌血管新生的调节。     

Endostatin Binds to Blood Vessels in Situ Independent of Heparan Sulfate and Does Not Compete for Fibroblast Growth Factor-2 Binding

Endostatin is a carboxyl-terminal proteolytic fragment of collagen XVIII and a potent inhibitor of angiogenesis. The mechanism of action is unknown, but the crystal structure of endostatin predicts a prominent heparan sulfate binding site, suggesting that endostatin competitively inhibits heparin-binding angiogenic factors, such as basic fibroblast growth factor (FGF-2). The goal of the study was to map endostatin binding sites in intact human tissues and to determine whether this binding is heparan sulfate dependent. In situ binding was performed with recombinant epitope-tagged murine endostatin. Endostatin predominantly binds to blood vessels of different calibers in a saturable fashion. In addition, binding to some epithelial basement membranes is seen. The localization pattern is similar to that reported for collagen XVIII, endostatin's parent molecule. In breast carcinomas, endostatin co-localizes largely with FGF-2. In a surprising contrast to FGF-2, endostatin binding is resistant to treatment with heparitinase, demonstrating that binding is not mediated by heparan sulfate proteoglycans. Furthermore, FGF-2 and heparin do not compete for endostatin binding, providing additional evidence for the discreteness of endostatin and FGF-binding sites.     

A potent antiangiogenic factor, endostatin prevents the development of asthma in a murine model

BACKGROUND: Clinical studies suggest a role for angiogenesis in the development and persistence of chronic asthma, but whether angiogenic mediators contribute to acute asthma has not been fully studied. OBJECTIVE: The aim of this study was to investigate a role of vascular endothelial growth factor (VEGF), a major angiogenic and proinflammatory mediator, in allergen-induced acute asthma and to determine whether endostatin/Fc, a potent antiangiogenic factor can attenuate allergic airway responses. METHODS: We sensitized BALB/c mice with ovalbumin. We measured serum VEGF and examined immunoreactive VEGF around the airways 48 hours after the last challenge with either aerosolized PBS or ovalbumin once per day for 3 days. We also treated ovalbumin-sensitized mice with either endostatin/Fc or control fusion protein at the time of challenge with ovalbumin. We analyzed allergic airway responses 48 hours after the last ovalbumin challenge. RESULTS: Ovalbumin challenge induced immunolocalization of numerous VEGF-positive cells around airways and increased serum VEGF levels. Treatment with endostatin/Fc inhibited the airway hyperresponsiveness, pulmonary allergic inflammation, production of ovalbumin-specific IgE, and lung inflammatory mediators. Both VEGF-dependent and independent mechanisms are indicated by results using antibody blockade of VEGF receptors, which caused decreased allergic pulmonary inflammation but did not alter airway hyperresponsiveness or serum IgE levels. CONCLUSION: These data demonstrate for the first time that recombinant endostatin can prevent the development of asthma features in a mouse model and suggest that this class of agents merits further study as novel therapeutics for asthma.     

大肠杆菌表达的新一代重组人内皮抑素复性条件的优化

目的优化新一代重组人内皮抑素(rhED)的复性方案并检测其抗血管生成活性。方法用6 mol/L盐酸胍溶解rhED包涵体后,用稀释法与透析法相结合的方法进行复性,优化最适复性条件。复性结束后用阳离子交换层析纯化。并用rhED特异性单抗和鸡胚绒毛尿囊膜实验检测复性后蛋白的活性。结果通过优化复性条件,rhED的复性率可达到46%。复性、纯化后的rhED能与rhED特异性单抗反应,并在鸡胚绒毛尿囊膜实验中显示出抑制血管生长的活性。结论提高rhED复性率的复性条件可极大地促进新一代rhED的临床前及临床研究。     

Identification of differentially expressed genes in a renal cell carcinoma tumor model after endostatin-treatment

Endostatin is a cleavage product of collagen XVIII that has shown to inhibit tumor-angiogenesis in experimental tumor models. At present, the exact molecular mechanism of action of endostatin is not completely elucidated. In this study, we wanted to identify specific target genes of endostatin. For this purpose, the human renal cell carcinoma RC-9 was subcutaneously implanted in nude mice and treated with endostatin. Tumor growth was inhibited by endostatin after 4 days of treatment. Using immunohistochemistry and the hypoxia marker pimonidazole, we demonstrate disintegration of blood vessels and hypoxia and anoxia as a result of the treatment. Hereafter, we applied the polymerase chain reaction (PCR)-based subtractive suppression hybridization (SSH) method, together with the mirror orientation selection (MOS) technique to identify specifically induced and suppressed genes after endostatin-treatment. We found eight genes to be specifically induced and 11 to be suppressed by the endostatin-treatment. Among other genes, core binding factor a-1/osteoblast-specific factor-2 (cbfa1/osf2) was found to be specifically suppressed by endostatin. Unexpectedly, cbfa1/osf2 was found to be specifically expressed in granulocytes in the tumor, not only in the experimental RC-9 tumor model, but in sections of human breast cancer as well. Since an effect of antiangiogenic therapy on granulocytes has been reported before, this might lead to new insights in the role of granulocytes in antiangiogenic therapy in general. In conclusion, the SSH-PCR implemented with the MOS-technique is a powerful tool to identify differentially expressed genes. Using these techniques, we have identified several target genes of endostatin, of which cbfa1/osf2 was found to be specifically expressed in granulocytes in the tumor.     

内皮抑素和多西环素抑制黑色素瘤浸润转移相关蛋白表达的研究

目的 研究内皮抑素和多西环素对黑色素瘤生长及肿瘤细胞基质金属蛋白酶-9（MMP-9）、-2（MMP-2）及基质金属蛋白酶组织抑制因子（TIMP-2）表达水平的影响。方法 C57／BL6小鼠57只,建立小鼠B16黑色素瘤动物模型,分多西环素组、多西环素加内皮抑素组,内皮抑素组和对照组4组,给予内皮抑素和多西环素处理,比较肿瘤的体积大小及生长速度,免疫组织化学染色检测肿瘤组织MMP-9、MMP-2及TIMP-2的表达。结果多西环素组、多西环素加内皮抑素组和内皮抑素组肿瘤均较对照组生长缓慢（F=4．32,P＜0．05）,其中多西环素组、多西环素加内皮抑素组和对照组之间肿瘤平均生长体积差异有统计学意义（t=2．40,t：2．58;P＜0．05）。MMP-2、MMP-9和TIMP-2在各处理组的表达与在对照组的表达之间差异均有统计学意义（F=12．79,F=5．56,F=4．64;P＜0．05）。结论 多西环素和内皮抑素联合使用,影响肿瘤组织MMPs及其抑制剂的表达,明显抑制黑色素瘤生长和局部浸润转移。