RNA干扰敲减FucT Ⅶ表达抑制人结肠癌细胞HT-29和HUVECs的粘附能力

探讨利用RNA干扰(RNAi)技术抑制岩藻糖基转移酶Ⅶ(FucT Ⅶ)表达对人结肠癌细胞HT-29与人脐静脉内皮细胞(HUVEC)粘附能力的影响及其机制.本课题构建3对针对FucT Ⅶ基因的RNAi表达载体,并将其转染入人结肠癌细胞HT-29,Western印迹检测FucT Ⅶ及其下游产物sLeX蛋白的变化;实时PCR检测FucT Ⅶ mRNA表达的变化;玫瑰红染色法检测RNAi对HT-29与HUVECs细胞粘附能力的影响.结果显示,3对FucT Ⅶ siRNA表达载体均可有效抑制HT-29细胞FucT Ⅶ mRNA和蛋白表达,以pSilencer 2.0-FucT Ⅶ 2最为有效;与空白细胞组比较,转染pSilencer 2.0-FucT Ⅶ的HT-29细胞表面sLeX表达水平明显下降,以pSilencer2.0-FucT Ⅶ 2最为显著;RNA干扰FucT Ⅶ表达后HT-29细胞和HUVEC之间的粘附能力明显受到抑制.研究表明,RNAi靶向沉默HT-29细胞中FucT Ⅶ基因表达可显著降低其下游产物sLeX的合成,进而抑制HT-29细胞与HUVECs的粘附能力.     

NSCLC中低氧诱导因子-1α对血管生成素-2表达的影响

目的探讨非小细胞肺癌(non-small cell lung cancer,NSCLC)中低氧诱导因子-1α(hypoxia-inducible fac-tor-1α,HIF-1α)对血管生成素-2(angiopoietin-2)表达的影响及意义。方法免疫组化SP法检测46例NSCLC组织HIF-1α、血管生成素-2蛋白的表达;培养人肺腺癌细胞株A549细胞,CoCl2模拟缺氧处理6h、12h、24h,以及缺氧条件下不同浓度genistein处理细胞12h后,采用Western Blot和RT-PCR方法分别检测A549细胞HIF-1α蛋白和血管生成素-2 mRNA的表达情况。结果46例NSCLC中HIF-1α、血管生成素-2的阳性表达率分别为73.9%(34/46)、63.0%(29/46),明显高于癌旁肺组织(P<0.05);HIF-1α的表达与血管生成素-2的表达呈正相关。急性缺氧可以诱导A549细胞HIF-1α蛋白和血管生成素-2 mRNA表达增加,分别在6h,12h达到高峰,随着缺氧时间延长,HIF-1α蛋白和血管生成素-2 mRNA表达相对减少;genistein抑制HIF-1α蛋白后,血管生成素-2 mRNA的表达也相应减少,呈浓度依赖。结论缺氧时NSCLC中HIF-1α可参与血管生成素-2的调控,HIF-1α、血管生成素-2表达增加与肿瘤新生血管形成有关,二者共同促进NSCLC的发生发展过程。     

原核表达Arresten蛋白抑制血管生成作用

目的:研究原核表达的Arresten蛋白纯化品对血管内皮细胞及血管生成的抑制作用。方法:MTT法检测Arresten蛋白对人脐静脉内皮细胞(HUVEC)增殖的影响;流式细胞仪分析Arresten蛋白作用下HUVEC凋亡的情况;细胞迁移实验观察Arresten蛋白对HUVEC迁移能力的影响;鸡胚绒毛尿囊膜(CAM)实验观察Arresten蛋白对新生血管的抑制情况。结果:原核表达的Arresten蛋白纯化品能特异性地抑制 HUVEC的增殖、迁移,诱导HUVEC的凋亡,并在一定范围内呈现出剂量—效应关系。Arresten蛋白能有效抑制鸡胚尿囊膜血管的生长(P<0.01)。结论:原核表达的Arresten蛋白纯化品对内皮细胞有特异的抑制作用,能有效抑制血管生成。     

蝎毒多肽提取物的抗血管生成作用

用不同浓度的东亚钳蝎素的多肽提取物PESV(4～20μg／ml)作用于人脐静脉内皮细胞(HUVEC),观察HUVEC增殖活性和凋亡变化,增殖活性检测采用BrdU掺入的ELISA法,凋亡水平和凋亡相关基因Bcl-2和Bax表达的检测采用流式细胞术检测;用鸡胚尿囊膜(CAM)显示PESV对血管生成的抑制作用。结果显示,PESV抑制HUVEC的增殖,而对乳腺癌细胞MDA-MB-231的增殖无明显影响;PESV作用72h后,HUVEC凋亡相关基因Bcl-2表达降低,Bax表达增加,凋亡细胞比例增至10．5％,明显高于对照组;0．5mgPESV能明显抑制CAM新生血管的形成。因此,PESV具有良好的体外抗肿瘤血管生成活性,PESV作为一种肿瘤血管抑制剂的天然药物来源,其有效成分和药理作用有待进一步研究。     

RNA干扰敲减FucT VII表达抑制人结肠癌细胞HT-29和HUVECs的粘附能力

 探讨利用RNA干扰（RNAi）技术抑制岩藻糖基转移酶Ⅶ（FucT Ⅶ）表达对人结肠癌细胞HT-29与人脐静脉内皮细胞（HUVEC）粘附能力的影响及其机制.本课题构建3对针对FucT Ⅶ基因的RNAi表达载体,并将其转染入人结肠癌细胞HT-29,Western 印迹检测FucT Ⅶ及其下游产物sLeX蛋白的变化;实时PCR 检测FucT Ⅶ mRNA表达的变化;玫瑰红染色法检测RNAi 对HT-29与HUVECs细胞粘附能力的影响.结果显示,3对FucT Ⅶ siRNA表达载体均可有效抑制HT-29细胞FucT Ⅶ mRNA和蛋白表达,以pSilencer 2.0 FucT Ⅶ 2最为有效;与空白细胞组比较,转染pSilencer 2.0-FucT Ⅶ的HT-29细胞表面sLeX表达水平明显下降,以pSilencer 2.0-FucT Ⅶ 2最为显著;RNA干扰FucT Ⅶ表达后HT 29细胞和HUVEC之间的粘附能力明显受到抑制.研究表明,RNAi靶向沉默HT-29细胞中FucT Ⅶ基因表达可显著降低其下游产物sLeX的合成,进而抑制HT-29细胞与HUVECs的粘附能力.     

香叶木素和香叶木素-7-O-β-D-吡喃葡萄糖苷的生物活性比较

研究香叶木素和香叶木素-7-O-β-D-吡喃葡萄糖苷对不同肿瘤细胞(MCF-7、MDA-MB-231和A549)和血管内皮细胞(HUVECs)的细胞毒性及作用机制。正常培养的肺腺癌细胞(A549)、乳腺癌细胞(MCF-7、MDAMB-231)及血管内皮细胞(HUVECs)经不同浓度的香叶木素和香叶木素-7-O-β-D-吡喃葡萄糖苷(20、40、80、160μM)分别处理24和48 h,倒置显微镜观察细胞形态,SRB法检测细胞存活率;吖啶橙染色观察细胞核凝集和片段化;Hoechst 33258检测细胞凋亡;荧光探针DCHF检测细胞内活性氧(ROS);Western blot检测膜联蛋白A7(ANXA7)、P62、procaspase3和LC3的表达。结果表明,香叶木素以剂量依赖的方式抑制肿瘤细胞MDA-MB-231、MCF-7、A549的增殖和去血清条件下血管内皮细胞的增殖,通过上调LC3-Ⅱ的水平,促进肿瘤细胞自噬。香叶木素-7-O-β-D-吡喃葡萄糖苷对去血清条件下血管内皮细胞有保护作用,显著降低去血清条件下血管内皮细胞的细胞凋亡和细胞核片段凝集,显著降低细胞内ROS水平,下调caspase3和LC3-Ⅱ的水平。香叶木素和香叶木素-7-O-β-D-吡喃葡萄糖苷具有不同的生物活性。香叶木素是一种潜在的抗肿瘤化合物,而香叶木素-7-O-β-D-吡喃葡萄糖苷可能成为一种保护HUVECs的有效药物。     

白芨中萜类化合物通过诱导血管内皮细胞凋亡抑制血管生成

本文研究了白芨中的萜类化合物对血管生成的抑制作用．及其抑制血管生成的可能机制。采用萃取和色谱法从白芨中分离和纯化了该萜类化合物。通过鸡胚绒毛囊膜（CAM）和人脐静脉内皮细胞（HUVEC）研究了白芨中萜类化合物及其粗提物对血管及血管内皮细胞的抑制作用。结果表明,含该萜类的粗提物显著抑制鸡胚绒毛尿囊膜血管生成;该萜类纯品能明显抑制HUVEC增殖,且可诱导HUVEC凋亡,包括细胞体积缩小,细胞膜起泡,细胞核裂解,染色质浓缩和边集,出现凋亡小体,DNA降解。因此．白芨萜类化合物的抗血管生成作用与诱导血管内皮细胞凋亡有关。     

广西沿海四种红树植物抗肿瘤活性的筛选

该研究采用超声提取法,得到红海榄的叶、秋茄的茎和叶、水黄皮的叶和桐花树的茎的95%乙醇提取物,并用MTS法检测提取物对前列腺癌DU145、PC3细胞增殖抑制效果,结果桐花树茎95%乙醇提取物对DU145细胞增殖抑制作用最强,对DU145干预24、48、72 h的IC₅₀分别为75.23、88.81、76.53 μg·mL^-1。在此基础上,依次采用石油醚、乙酸乙酯、正丁醇对桐花树茎95%乙醇提取物进行梯度萃取,得到不同极性部位后选择桐花树茎乙酸乙酯部位(EACS)对19种肿瘤细胞(HT-29,SW480,DLD-1,COLO205,PC3,DU145,SKOV3-S,A2780,SGC-7901,Tca-8113,MDA-MB-231,HepG2,SMMC-7721,Bel-7402,MHCC-97H,Hela,PANC-1,EJ,A549)和3种正常细胞(HUVEC,EC304,RWPE-1)进行MTS实验检测其抗增殖作用,用集落形成进一步检测EACS对细胞HT-29、DLD-1、SW480、DU145、PC3、SKOV3-S的增殖影响。结果表明:EACS对16个肿瘤细胞和3个正常细胞均具有不同程度的增殖抑制作用,其中对RWPE-1的增殖抑制作用最强,药物作用72 h后的IC₅₀为22.78 μg·mL^-1; EACS对细胞HT-29、DLD-1、SW480、DU145、PC3、SKOV3-S的集落形成均具有抑制作用,抑制作用强度与浓度成正相关关系。     

miR-195/VEGFA信号通路对脑梗死后血管生成的影响

为了揭示miR-195/VEGFA信号通路对脑梗死后血管生成的影响,本研究测定了大脑中动脉闭塞(middle cerebral artery occlusion, MCAO)模型大鼠脑中的miR-195表达,以及miR-195对人脐静脉血管内皮细胞(human umbilical vein vascular endothelial cell, HUVEC)的细胞侵袭和血管形成的影响。此外,检测了miR-195对血管内皮生长因子A (vascular endothelial growth factor A, VEGFA)表达的影响。研究显示,MCAO组大鼠中miR-195表达显著下调。缺氧处理可导致HUVEC中miR-195表达显著降低。miR-195的下调促进了HUVEC在缺氧条件下的血管生成和细胞侵袭。miR-195模拟物处理可显著下调VEGFA m RNA和蛋白质表达水平。VEGFA的过表达逆转了miR-195过表达对细胞侵袭和小管形成的抑制作用。研究表明miR-195通过靶向VEGFA在缺氧条件下调节脑梗死后的血管生成。     

缺氧诱导因子与肾细胞癌关系的研究进展

缺氧诱导因子(hypoxia inducible factor,HIF)对维持肿瘤细胞的能量代谢、肿瘤血管生成、促进肿瘤细胞增殖和转移起着重要作用,是肿瘤细胞低氧条件下产生的关键信号分子。本综述旨在总结前人研究,阐述HIF与肾癌细胞之间的内在关系。HIF成员是参与肾癌细胞对缺氧应答反应中的关键因子,并通过靶基因的调节,促进新生血管的生成,导致肿瘤生长。其中,HIF-1α及HIF-2α在促进新生血管的生成方面发挥着主要作用。HIF-1α及HIF-2α与VEGF密切相关,随着其的表达增高,VEGF在数量上及m RNA水平上均显著增高,显示其可通过调控VEGF参与肾癌血管生成,而HIF-2α转录激活VEGF m RNA的特异性较HIF-1α更强。HIF-3α可能存在的负性调控作用,其异构体-4的作用可能与HIF-lα的负性调节有关,其可以阻止HIF-lα与下游靶基因的缺氧反应元件(hypoxia response elements,HRE)结合,同时可在转录水平抑制HIF-lα。HIF在未来可能有成为肾细胞癌治疗的靶点。     

Conventional, regulatory, and unconventional T cells in the immunologic response to Helicobacter pylori

Infection by the gastroduodenal pathogen Helicobacter pylori elicits a complex immunologic response in the mucosa involving neutrophils, plasma cells, eosinophils, and lymphocytes, of which T cells are the principal orchestrators of immunity. While so-called classical T cells (e.g. T-helper cells) that are activated by peptide fragments presented on antigen-presenting cells have received much attention in H. pylori infection, there exists a diverse array of other T cell populations that are potentially important for the outcome of the ensuing immune response, some of which have not been extensively studied in H. pylori infection. Pathogen-specific regulatory T cells that control and prevent the development of immunopathology associated with H. pylori infection have been investigated, but these cells can also benefit the bacterium in helping to prolong the chronicity of the infection by suppressing protective immune responses. An overlooked T cell population, the more recently described Th17 cells, may play a role in H. pylori-induced inflammation, due to triggering responses that ultimately lead to the recruitment of polymorphs, including neutrophils. The so-called innate or unconventional T cells, that include two conserved T cell subsets expressing invariant antigen-specific receptors, the CD1d-restricted natural killer T cells which are activated by glycolipids, and the mucosal-associated invariant T cells which play a role in defense against orally acquired pathogens in the intestinal mucosa, have only begun to receive attention. A greater knowledge of the range of T cell responses induced by H. pylori is required for a deeper understanding of the pathogenesis of this bacterium and its ability to perpetuate chronic infection, and could reveal new strategies for therapeutic exploitation.     

Calbindin D28k, parvalbumin, and calretinin immunoreactivity in the main and accessory olfactory bulbs of the gray short-tailed opossum, Monodelphis domestica

The vertebrate main and accessory olfactory bulbs (MOB and AOB) are the first synaptic sites in the olfactory pathways. The MOB is a cortical structure phylogenetically well conserved in its laminar structure and overall synaptic organization, while the AOB has significant species variation in size. In order to better understand signal processing in the two olfactory systems and the species differences, immunocytochemical staining and analysis were done of the neuronal expression patterns of the calcium-binding proteins calbindin D28k (CB), parvalbumin (PV), and calretinin (CR) in the MOB and AOB in a marsupial species, the gray short-tailed opossum, Monodelphis domestica. In the MOB, antibody to CB labeled periglomerular cells, superficial short axon cells / Van Gehuchten cells; antibody to PV labeled Van Gehuchten cells; and antibody to CR immunostained periglomerular cells, superficial short axon cells / Van Gehuchten cells, and granule cells. In the AOB, CB immunoreactivity was detected in periglomerular cells and a subpopulation of granule cells; antibody to PV labeled the superficial short axon cells / Van Gehuchten cells and granule cells; and antibody to CR labeled a small number of periglomerular cells, superficial short axon cells / Van Gehuchten cells, and granule cells. These results showed that the patterns of CB, PV, and CR expression differ in the opossum main and accessory olfactory bulbs and differ from that in other animal species. These varying patterns of neuronal immunostaining may be related to the different functions of the main and accessory olfactory bulbs and to the differing signal processing features.     

Natural killer lymphocytes: biology,development, and function

Natural killer (NK) lymphocytes represent the first line of defense against virally infected cells and tumor cells. The role of NK cells in immune responses has been markedly explored, mainly due to the identification of NK cell receptors and their ligands, but also through the analysis of mechanisms underlying the effects of various cytokines on NK cell development and function. A population of lymphocytes that shares function and receptors with NK cells is represented by natural killer T (NKT) cells. NKT lymphocytes are regulators of both innate and adaptive immune responses, but have also been reported to function as effector antitumor cells. The marked progress in our understanding of the biology, development, and function of NK/NKT cells has provided the basis for their potential application in tumor clinical trials.This work was presented at the first Cancer Immunology and Immunotherapy Summer School, 8–13 September 2003, Ionian Village, Bartholomeio, Peloponnese, Greece.     

Inhibin alpha-iCre mice: Cre deleter lines for the gonads, pituitary, and adrenal

To expand our knowledge of reproductive function, Cre lines to conditionally knockout essential genes in the mouse gonads were generated. Three transgenic lines of inhibin-alpha-iCre mice were designed by fusing the mouse inhibin-alpha promoter with a codon-improved Cre recombinase (iCre). alpha-iCre-line-3 expressed high levels of Cre in Sertoli and Leydig cells of the testis and low levels in other tissues, making line 3 an appropriate deleter line for genes expressed in somatic cells of the testis. In contrast, alpha-iCre-line-1 expressed high levels of Cre in granulosa and theca cells of the ovary and very low levels in other tissues, making line 1 a suitable deleter line for genes expressed in somatic cells of the ovary. A third line, alpha-iCre-line-2, had low levels of Cre in the gonads but high levels in anterior pituitary and adrenal medulla. These lines could be useful to understand reproduction and other processes by establishing conditional knockout mouse models.     

Stemness of T cells and the hematopoietic stem cells: Fate,memory, niche,cytokines

Stem cells are able to generate both cells that differentiate and cells that remain undifferentiated but potentially have the same developmental program. The prolonged duration of the protective immune memory for infectious diseases such as polio, small pox, and measles, suggested that memory T cells may have stem cell properties. Understanding the molecular basis for the life-long persistence of memory T cells may be useful to project targeted therapies for immune deficiencies and infectious diseases and to formulate vaccines. In the last decade evidence from different laboratories shows that memory T cells may share self-renewal pathways with bone marrow hematopoietic stem cells. In stem cells the intrinsic self-renewal activity, which depends on gene expression, is known to be modulated by extrinsic signals from the environment that may be tissue specific. These extrinsic signals for stemness of memory T cells include cytokines such as IL-7 and IL-15 and there are other cytokine signals for maintaining the cytokine signature (TH1, TH2, etc.) of memory T cells. Intrinsic and extrinsic pathways that might be common to bone marrow hematopoietic stem cells and memory T lymphocytes are discussed and related to self-renewal functions.     

Comparative immunocytochemical demonstration of ACTH-, LH and FSH-containing cells in the pituitary of neonatal,immature and adult rats

Summary By means of immunocytochemistry, the development of ACTH-, LH- and FSH cells was examined in the anterior pituitary of 5-day-old neonatal, 15-day-old immature and adult rats. ACTH-positive cells are angular and the periphery of these cells is strongly reactive with anti-ACTH serum. In contrast, LH- and FSH-immunopositive cells are ovoid elements, ranging in cell size and intensity of staining. Angular cells, in which only the cell periphery reacted with anti-LH serum, were observed in neonatal and immature rats; however, these cells were not stained with either anti-FSH serum or anti-ACTH serum. Observation of serial semithin sections revealed that ACTH-immunopositive cells do not react with either anti-LH or anti-FSH serum. Finally, it was observed that ACTH cells and LH cells are both functionally differentiated already in 5-day-old neonatal rats.     

Calmodulin-Dependent Phosphatases of PC12, GH3, and C6 Cells: Physical, Kinetic, and Immunochemical Properties

Calmodulin-dependent phosphoprotein phosphatase (CaMDP) activity has been found in each of three cultured cell lines: rat pheochromocytoma (PC12), glioma (C6), and pituitary adenoma (GH3) cells. These CaMDP activities bind to immobilized calmodulin in the presence of Ca2+ and are eluted by EGTA. Sucrose density centrifugation revealed that the phosphatase activities exhibited sedimentation coefficients of 4.37, 4.23, and 4.59 for proteins derived from C6, GH3, and PC12 cells, respectively. The Stokes radii measured for the PC12 and C6 activities were 41.8 and 40.0 A, respectively. The estimated molecular weights calculated for the enzymes from these data are 79,100 and 72,200. The phosphatase activities required the presence of divalent cations such as Ca2+ or Mn2+ for expression of activity, which was optimal only in the presence of calmodulin. The apparent Km for phosphorylated myelin basic protein substrate was 8 microM. Affinity-purified antibodies to the B subunit of bovine brain CaMDP were found by immunoblot (Western blot) to cross-react with a single protein among proteins extracted from PC12, C6, and GH3 cells that had been resolved by two-dimensional electrophoresis. In each case, the cross-reacting protein exhibited an Mr of 16,000 and an isoelectric point of 4.7, values virtually identical to those reported previously for the B subunit of bovine brain CaMDP (sometimes called calcineurin). This cross-reacting protein was found among cellular proteins eluted from immobilized calmodulin by EGTA. Immunocytochemical localization of the cross-reacting protein in undifferentiated PC12 cells or in cells differentiated in response to nerve growth factor revealed its presence diffusely throughout the cytoplasm. These experiments support the contention that each of these cell lines contains a calmodulin-regulated phosphatase homologous physically and kinetically, and immunologically related to bovine brain CaMDP.     

Histological, histochemical, enzyme histochemical and ultrastructural investigations of the testis of Padogobius martensi between annual breeding seasons

From July to March, the testis of the spring‐spawning freshwater goby Padogobius martensi is characterized by spermatogonial proliferation. A close correlation exists among type of proliferating spermatogonia, gonado‐somatic (I_G) profiles and morphological and functional variations of the Leydig cells. The I_G reach their minimal levels by the end of summer and increase progressively but modestly during autumn and winter. Declining I_G levels are associated with proliferation of primary spermatogonia only, whereas increasing I_G levels are associated with predominant proliferation of secondary spermatogonia. Minimal I_G levels are reached when the germinal epithelium is formed by a continuum of primary spermatogonia and associated Sertoli cells. The proliferation of secondary spermatogonia begins only at this time. Spermatogenesis in autumn occurs when spermatogonial cysts contain at the most 16 cells and it rarely results in the maturation of several cysts so that the amount of sperm cells produced is either negligible or scarce. A number of degenerating cells are usually present within the spermatogonial and meiotic cysts. Leydig cells are the unique cells that display features of steroidogenic cells: mitochondria with tubular cristae, extensive smooth endoplasmic reticulum (SER), 3β‐hydroxysteroid dehydrogenase (3β‐HSD) and glucose‐6‐phosphate dehydrogenase (G6PD) activity and sudanophilia. Light and dark Leydig cell varieties are always present. During regression, Leydig cells undergo a marked decrease in SER amount, mitochondrial sizes and number of mitochondrial cristae. In parallel, the 3β‐HSD and G6PD activities and sudanophilia decrease progressively until they become undetectable by the end of regression. In autumn, mitochondria increase in size, reaching sizes similar to those observed at the end of the spawning season in the light cells, but not in the dark cells. The SER, on the contrary, undergoes a modest and irregular increase only in a part of the Leydig cells, mostly of the light type. In parallel, the 3β‐HSD and G6PD activities increase until they become moderately intense by the end of autumn. At the end of winter, the SER is extensive and regularly dilated in both Leydig cell types, whereas mitochondria still have sizes similar to those observed in December. The 3β‐HSD and G6PD activities are strong and sudanophilia is again detectable. Sertoli cells undergo changes in shape and position in relation to the proliferation of primary spermatogonia and the development of cysts. A junction modulation occurs in association with these changes. Sertoli cells also undergo changes indicative of a decrease in activity immediately after spawning (loss of mitochondrial cristae and clarification of the mitochondrial matrix) and of an increase in activity by the end of the regressing phase (darkening of the mitochondrial matrix and increase in mitochondrial cristae, rough endoplasmic reticulum (RER) and free ribosomes). In addition, they are involved in the phagocytosis of degenerating germ cells at all stages of their development. Macrophages are found in the testis interstitium only, where they are usually adjacent to Leydig cells, myoid cells and blood capillaries and do not participate in the phagocytosis of degenerating germ cells. Myoid cells do not undergo ultrastructural changes except for an increase in the amount of heterochromatin by the end of spawning. The meaning of the autumnal spermatogenic wave and the relationships between the development of the germinal epithelium and the changes of the Leydig and Sertoli cells are discussed.