Specific anti-tumor effect induced by attenuated <Emphasis Type="Italic">Salmonella typhimurium</Emphasis> vaccine expressing extracellular region of vascular endothelial growth factor receptor 2

The purposes of this research were to study the stable expression of exogenous gene encoding therapeutic protein in attenuated Salmonella typhimurium, observe the metabolism of oral gene vaccine carried by attenuated Salmonella typhimurium in BALB/c mouse, and investigate the feasibility of prevention and treatment of tumors by the recombinant bacteria. Recombinant plasmid pcDNA3.1＋ VEGFR2（n1-7） was transformed into competent attenuated Salmonella typhimuriurn SL3261 to develop oral DNA vaccine SL3261-pcDNA3.1＋VEGFR2（n1-7）. To observe whether the exogenous gene can be expressed in the recombinant bacteria, PCR was performed to amplify the CMV promoter of the eukaryotic expression vector as the proof of stable expression of exogenous protein; transmission elec- tron microscopy （TEM） was applied to observe the morphology of the recombinant bacteria to confirm that the exogenous gene has no impact on the growth of the bacteria, and then BALB/c mice were immunized with the gene vaccine. After inoculation of the gene vaccine, the recombinant bacteria SL3261 could be detected in the tissues such as small intestine, colon, liver and spleen. And then, mice in each group were challenged with tumor cells. The results of animal experiment showed that tumor growth of the mice in experimental group was inhibited and survival time of immunized mice was prolonged compared with control groups. A higher lymphocyte infiltration in tumors from animals treated with DNA vaccine was observed. Immunohistochemical analysis of tumor samples revealed an enhanced accumulation of CD8^＋ cytotoxic T lymphocytes, as well as an increase in CD4^＋ cells in the tumore of animals treated with the oral gene vaccine compared to tumors from control group mice. UI- trestructure of the tumor tissue showed that tumor cells in the samples of the immunized mice were well-differentiated. Our research confirmed that the exogenous gene can be stably expressed in the attenuated Salmonella typhimurium and has no impact on the growth of the r     

血管内皮生长因子受体靶向的紫杉醇胶束的制备及其缓释效果

利用PLGA-PEG嵌段聚合物的两亲性质制备了3种不同PEG分子量的内部包载药物的血管内皮生长因子受体靶向胶束APRPG-PEG-M。通过对制剂粒径分布、zeta电位、包封率及载药量等方面的考察,确定处方和制备工艺,并考察其制剂学性质。制备的靶向胶束呈球形或类球形,粒径109.7~119.9nm、包封率89.2%~91.5%,在体外释药试验中48h累积释放量为47.8%~60.0%,表现出明显的缓释效果。制备的紫杉醇靶向胶束在体外对药物释放具有良好的缓释效果。     

Expression of vascular endothelial growth factor in rat uterus during peri-implantation

The first distinct mark of rodent implantation is the increased vascular permeability and significant angiogenesis at the sites of blastocyst implantation, but its mechanism is not clearly defined. Vascular endothelial growth factor (VEGF) is the key mediator for angiogenesis during embryogenesis and adult span and also serves as a vascular permeability factor. The aim of this study is to explore VEGF regulation mechanism and the possible role that VEGF plays in implantation by studying the VEGF expression and angiogenesis in the rat uterus during estrous cycle, ovarioectomized and peri-implantation stages usingin situ message RNA hybridization and confocal laser scanning techniques. The results indicated that VEGF was regulated by ovarian steroid hormones. VEGF expression before implantation was localized at luminal epithelium, shifted to stroma as implantation initiated and extensively located at the decidualizing stroma region after implantation. Bandeiraea simplicifolia-1 (BS-1) agglutinin and antibody against von Willebrand factor (vWF) were used to mark the endothelial cells and blood vessels. The results showed that the active angiogenesis occurred during the implantation process and this effect was probably mediated by VEGF. The results suggest that under the regulation of ovarian steroid hormones, VEGF plays an essential role in angiogenesis and increasing vascular permeability in endometrium, which are necessary for successful implantation.     

重组人血管内皮细胞生长因子的表达及活性研究

目的 :用基因工程的方法在大肠杆菌中诱导表达人血管内皮生长因子 (VEGF) ,分离纯化并检测其生物学活性 ,以研究其在药学领域潜在的药用价值。方法 :利用PCR技术扩增VEGF基因片段 ,克隆到pQE30表达载体中 ,转化E .coliM15菌株后用IPTG进行诱导表达。经裂解细胞、变性、复性和Ni-NTAagarose金属螯合柱层析等方法纯化得到VEGF。用鸡胚绒毛尿囊膜 (CAM)血管生成实验检测VEGF的生物活性。结果 :重组表达质粒在大肠杆菌中成功地表达了相对分子质量为 2 0 6 0 0的融合蛋白 ,它以不溶性的包涵体形式存在 ,占菌体总蛋白的 30 %左右。经分离纯化融合蛋白SDS -PAGE显示为单一区带。CAM结果表明给药组血管生成数 (2 1 7± 3 1、39 3± 2 8)与对照组 (15 4± 1 9、2 9 2± 4 2 )相比有明显增加 (P <0 0 5 )。结论 :利用原核表达系统得到血管内皮生长因子具有天然VEGF生物学活性 ,为进一步的应用研究奠定了基础。     

Expression of bcl-2 gene increases in apoptosis of vascular endothelial cells induced by rattlesnake venom

Apoptosis of vascular endothelial cells (VEC) has been induced by deprivation of survival factors (aFGF and serum) and by rattlesnake venom. The expression of bcl-2 gene has been examined by Northern blotting in the two apoptosis inducing systems. Our results show that the expression of bcl-2 has not been detected in normal culture cells and in apoptotic cells induced by deprivation of survival factors. But in apoptotic cells induced by rattlesnake venom (10 g/mL), the expression of bcl-2 increases, and its mRNA exhibits two bands. The data first suggest that increasing expression and splitting of bcl-2 mRNA may play an important role in apoptosis of VEC induced by rattlesnake venom, and this finding is helpful to understanding the role of bcl-2 in regulation of apoptosis.     

重组人血管内皮生长因子165在大肠杆菌中的可溶性表达、纯化与体外活性评价

人血管内皮生长因子165(VEGF165)可有效促进血管新生和增加血管通透性,在伤口愈合方面有重要医疗价值。建立获取高纯度、高活性的优质重组VEGF165蛋白的方法具有重要意义。研究利用带有6组氨酸标签的二硫键形成蛋白A(Dsb A)的E.coli表达系统实现了Dsb A-VEGF165融合蛋白的可溶性表达;诱导过程中添加5%(v/v)的乙醇可显著提高工程菌中可溶性融合蛋白表达水平。融合蛋白通过Ni亲和层析粗纯,并经牛肠激酶酶切去除标签蛋白。随后利用肝素亲和层析精纯获得重组人VEGF165蛋白。非还原及还原SDS-PAGE电泳检测到分子量为约40 k Da的同源二聚体蛋白,促HUVEC细胞增殖实验显示重组蛋白具有较优的活性,EC50为13 ng/m L。研究实现了Dsb A-VEGF165的在E.coli中可溶性表达,建立了经济、高效的纯化方法,获得了高质量、高活性的重组人VEGF165蛋白。     

Expression ofbcl-2 gene increases in apoptosis of vascular endothelial cells induced by rattlesnake venom

Apoptosis of vascular endothelial cells (VEC) has been induced by deprivation of survival factors (aFGF and serum) and by rattlesnake venom. The expression ofbcl-2 gene has been examined by Northern blotting in the two apoptosis inducing systems. Our results show that the expression ofbcl-2 has not been detected in normal culture cells and in apoptotic cells induced by deprivation of survival factors. But in apoptotic cells induced by rattlesnake venom (10 ng/mL), the expression ofbcl-2 increases, and its mRNA exhibits two bands. The data first suggest that increasing expression and splitting ofbcl-2 mRNA may play an important role in apoptosis of VEC induced by rattlesnake venom, and this finding is helpful to understanding the role ofbcl-2 in regulation of apoptosis.     

电刺激小脑顶核促脑缺血后血管内皮生长因子表达的意义

探讨电刺激小脑顶核(FNS)对局部脑缺血后血管内皮生长因子(VEGF)表达和毛细血管新生的影响．以线栓法制成大鼠右侧大脑中动脉梗塞模型(MCAO)，大鼠随机分为假手术对照组、MCAO组、电刺激小脑顶(MCAO FNS)干预组，以免疫组织化学法检测VEGF、内皮细胞阳性表达及毛细血管记数，大脑中动脉梗塞后，缺血区神经元变性、坏死，VEGF、内皮细胞在半暗带有少量表达，毛细血管数较对照组增加，经电刺激小脑顶核干预后，VEGF、内皮细胞大量表达，毛细血管数目明显增加，有统计学差异．电刺激小脑顶核可通过促VEGF表达、内皮细胞增殖，从而促进毛细血管新生。     

Therapeutic angiogenesis induced by human hepatocyte growth factor gene in hindlimb ischemia of dogs

A preclinical study of treating peripheral srtery occlusive disease(PAD) was performed by using a hepatocyte growth factor(HGF) gene-expressing vector,plasmid pUDKH,in a dog model with complete ischemia of one hindlimb.After ligation of femoral artery of one hindlimb,pUDKH was transferred directly into the ischemic limb muscles.The angiogenic activity of the plasmid pUDKH was evaluated.On D 30 after injecting once of pUDKH at differ-ent doses into local muscles immediately after operation,the degree of augmentation of collateral vessel formation was significantly greater than that treated by blank vector.In addition,the blood flow rate of femoral artery in dogs treated with pUDKH was recovered on D90,while the folw rate was only 1/5 tp 1/3 in control dogs.The pulse amplitude of pUDKH-treated dogs was recovered on D90,but it was hardly detectable in most of the control dogs.The side effects of intramuscular transfection of pUDKH were also investi-gated,and no significant positive change was found.It is suggested that angiogenesis induced by HGF gene has the potential for clincal use in the treatment of peripheral arte-rial diseases.     

反义VEGF165基因对肝癌细胞生长的抑制作用

人肝癌细胞株SMMC-7721体外转染反义VEGR_(165)基因,观察反义VEGF_(165)基因对肝癌细胞生长的作用。用分子克隆的方法构建反义VEGF_(165)基因其核表达载体 pcDNA_3-as-VEGF_(165),用阳离子脂质体介导的基因转染技术,将反义基因转入SMMG-7721肝癌细胞株,观察反义VEGF_(165)基因抑制肝癌细胞 VEGF蛋白表达,抑制细胞增殖,促进细胞凋亡的作用。RT-PCR结果显示转染反义VEGF_(165)基因后肝癌细胞内 VEG mRNA水平显著下降;ELISA方法显示转染反义基因 2 d后培养液上清 VEGF蛋白分泌显著下降((142.01±7.95)vs(1 625.52±64.46)pg/mL,n=4,P<0.01);免疫组织化学染色显示在培养板中转染及义VEGF_(165)基因的肝癌细胞细胞数显著减少,仅有少数细胞表达VEGF蛋白。流式细胞仪结果显示转染反义VEGF_(165)基因2 d后肝癌细胞的存活率下降了 12.53％(n=4,P<0.05),而凋亡率则上升了 13.12％(n=4,P<0.01)。MTT法显示反义VEGF_(165)基因能显著抑制肝癌细胞的增殖。反义VEGF_(165)基因能显著的抑制肝癌细胞VEGF蛋白的表达,抑制细胞的增殖,促进肝癌细胞凋亡。因此反义VEGF_(165)基因治疗有望成为一种新的治疗肝癌的方法。     

Therapeutic angiogenesis induced by human hepatocyte growth factor (HGF) gene in rat myocardial ischemia models

Coronary arteriosclerotic cardiopathy is also named myocardial ischemia, which severely threatens humanhealth. Following the economic development and change of life style in China, population blood pressure, weight index and serum cholesterol level all rise. This prophesies incidence rate of coronary arteriosclerotic cardiopathy and stroke will increase year by year. Angioplasty and surgical bypass, the primary interventional therapies for these in-dividuals, are temporally limited by the prob…     

Therapeutic induction of angiogenesis by direct myocardial administration of an adenovirus vector encoding human hepatocyte growth factor gene and its safety

After the study in vitro and in rats, we assessed further the effects and safety of local angiogen therapy using intramyocardial delivery of an adenovirus carrying hepatocyte growth factor gene (Ad-HGF) in a canine ischemia model. The angiogenic activity of Ad-HGF was evaluated from three aspects. First, the augmentation of collateral vessel development was assessed by angiography 30 d after surgery. The results showed that the density of collateral vessels in treated group was higher than that of control group. Secondly, infarct size was evaluated by TTC staining and image analysis. The results showed that the infarct size of treated group was smaller than that of control group. Thirdly, the myocardial regional blood flow was determined by the method of colored microspheres. The results showed that the blood flow recovered to the level before ligation in treated group, but that of the control group was lower than normal level. In addition, during the study of chronic toxicity, we tested the anti-adenovirus antibodies by neutralization method. The antibodies yielded after the fourth injection decreased slowly from peak level and disappeared 12 weeks after drug withdrawal. Overall, Ad-HGF can promote angiogenesis in ischemic myocardium and reduce infarct size. So this method may be considered as a therapeutic angiogenesis induction strategy for ischemic disease including myocardial infarction and peripheral artery disease. At the same time, Ad-HGF could induce the yield of anti-adenovirus antibodies to neutralize adenovirus, which may be the mechanism of adenovirus clearance.     

封闭Her—2蛋白拮抗碱性成纤维细胞生长因子对人肝癌细胞的粘连效应

目的：探索碱性成纤维细胞生长因子(basic fibroblast growth,bFGF）影响癌细胞粘连的信号传递途径,提供抗癌治疗的线索。方法：以人肝癌细胞系（HepG2）为靶子,明确靶细胞存在Her-2蛋白表达的同时,利用Her-2蛋白抗体封闭靶细胞Her-2蛋白来研究bFGF作为配体与否的细胞粘连效应性。结果：靶细胞HepG2确实具有Her-2蛋白表达;利用抗体封闭靶细胞Her-2蛋白时,靶细胞明显地呈现拮抗bFGF作为配体的细胞粘连加强效应。结论：bFGF对人肝癌细胞粘连性的影响与Her-2基因蛋白介导的信号传递作用有关。