MicroRNA-34a inhibits human brain glioma cell growth by down-regulation of notch1

The effects of microRNA-34a (miR-34a)-regulated Notch1 gene on the proliferation and apoptosis of the human glioma cell line U87 were investigated in this study. The U87 cells were divided into miR-34a mimics, negative control, mock transfection and blank control groups in terms of different treatments. In miR-34a mimics group, human U87 glioma cells were transfected with miR-34a mimics by using lipofectamine 2000. The cells transfected with nonsense microRNA were set up as negative control group. Those treated with lipofectamine 2000 only were designated to the mock tranfection group. In the blank control group, the cells were cultured routinely and no treatment was given. The expression of miR-34a and Notch1 was detected by using real-time RT-PCR. Western blotting was employed to monitor the change in Notch1 protein. Cell proliferation and apoptosis were measured by CCK-8 and flow cytometry. The results showed that the proliferative ability of U87 cells was significantly reduced and the apoptotic cells increased in miR-34a mimics group relative to control groups. The expression of miR-34a was significantly up-regulated in mimics group as compared with control groups (P<0.05). Furthermore, Notch1 protein levels were significantly decreased in miR-34a mimics group when compared with control groups (P<0.05), but the mRNA expression of Notch1 showed no significant difference among these groups. It was concluded that miR-34a may suppress the proliferation and induce apoptosis of U87 cells by decreasing the expression of target gene Notch1, suggesting that miR-34a may become a promising gene therapeutic target for brain glioma.     

Expression of Transforming Growth Factor β1 in Mesenchymal Stem Cells: Potential Utility in Molecular Tissue Engineering for Osteochondral Repair

Summary: The feasibility of using gene therapy to treat full-thickness articular cartilage defects was investigated with respect to the transfection and expression of exogenous transforming growth factor (TGF)-β1 genes in bone marrow-derived mesenchymal stem cells (MSCs) in vitro. The full-length rat TGF-β1 cDNA was transfected to MSCs mediated by lipofectamine and then selected with G418,a synthetic neomycin analog. The transient and stable expression of TGF-β1 by MSCs was detected by using immunohistochemical staining. The lipofectamine-mediated gene therapy efficiently trans fected MSCs in vitro with the TGF-β1 gene causing a marked up-regulation in TGF-β1 expression as compared with the vector-transfected control groups, and the increased expression persisted for at least 4 weeks after selected with G418. It was suggested that bone marrow-derived MSCs were sus ceptible to in vitro lipofectamine mediated TGF-β1 gene transfer and that transgene expression persist-ed for at least 4 weeks. Having successfully combined the existing techniques of tissue engineering with the novel possibilities offered by modern gene transfer technology, an innovative concept, I.e.molecular tissue engineering, are put forward for the first time. As a new branch of tissue engineer-ing, it represents both a new area and an important trend in research. Using this technique, we have a new powerful tool with which: (1) to modify the functional biology of articular tissue repair along defined pathways of growth and differentiation and (2) to affect a better repair of full-thickness artic ular cartilage defects that occur as a result of injury and osteoarthritis.     

Construction of Smac gene-containing and human prostate specific antigen promoter-regulated vector and its expression

To construct an eukaryotic expression vector containing Smac gene and study the expression efficiency and specificity of prostate specific antigen（PSA） enhancer/promoter in a possible targeted gene therapy scheme for prostate cancer. Methods： PSA enhancer （PSAE） and promoter （PSAP） sequences were amplified using PCR method. CMV and T7 promoters were deleted from pcDNA3.1-Smac and replaced by the two specific fragments to generate pPSAE-PSAP-Smac. After transfection into different cell lines, the status of cells was observed. And then, we determined the relative concentration of Smac mRNA in RT-PCR. Results： The recombinant plasmid of pPSAE-PSAP-Smac was successfully constructed. And only the prostate cancer cell line PC-3 was suppressed after transfection with pPSAE-PSAP-Smac. However, other nonprostate lines were not. Moreover, the concentration of Smac mRNA regulated by PSA promoter and enhancer was higher in comparison to the CMV promoter-driven control vectors. Conclusion： An expression vector containing the Smac gene （based on elements of the PSA gene regulatory sequences） has been developed and shown to function in prostate cancer cell lines which provides a solid platform for launching clinical studies.     

PPM1D silencing by lentiviral-mediated RNA interference inhibits proliferation and invasion of human glioma cells

To construct a lentiviral shRNA vector targeting human protein phosphatase 1D magnesium-dependent(PPM1D) gene and detect its effectiveness of gene silencing in human gliomas,specific siRNA targets with short hairpin frame were designed and synthesized.DNA oligo was cloned into the pFU-GW-iRNA lentiviral expression vector,and then PCR and sequencing analyses were conducted to verify the constructs.After the verified plasmids were transfected into 293T cells,the lentivirus was produced and the titer of virus was determined.Real-time quantitative PCR and Western blot were performed to detect the PPM1D expression level in the infected glioma cells.PCR and Western blot analyses revealed the optimal interfering target,and the virus with a titer of 6×108 TU/mL was successfully packaged.The PPM1D expression in human glioma cells was knocked down at both mRNA and protein levels by virus infection.The expression of PPM1D mRNA and protein was decreased by 76.3% and 87.0% respectively as compared with control group.The multiple functions of human glioma cells after PPM1D RNA interference were detected by flow cytometry and cell counting kit-8(CCK-8).Efficient down-regulation of PPM1D resulted in significantly increased cell apoptosis and reduced cell proliferation and invasion potential in U87-MG cells.We have successfully constructed the lentiviral shRNA expression vector capable of stable PPM1D gene silencing at both mRNA and protein levels in glioma cells.And our data gave evidence that the reduced cell growth observed after PPM1D silencing in glioma cells was at least partly due to increased apoptotic cell death.     

Comparison of Anticoagulant Effects on Vein Grafts between Human TFPI Gene Transfection and Aspirin Oral Administration

To develop a more efficient antithrombotic way after coronary artery bypass grafting(CABG),the anticoagulant effects were compared of human tissue factor pathway inhibitor(TFPI) gene transfection and aspirin oral administration(traditional method) on vein grafts.An eukaryotic expression plasmid pCMV-(Kozak) TFPI was prepared.Animal model of carotid artery bypass graft-ing was constructed.In operation,endothelial cells of vein grafts in TFPI group and empty plasmid control group were transfected with pCMV-(Kozak) TFPI and empty plasmid pCMV respectively,while no transfection was conducted in aspirin control group.After operation,aspirin(2 mg·kg-1·d-1) was administered(i.g.) in aspirin control group.Three days later,grafts(n=10) were harvested for RT-PCR,Western blotting and immunohistochemical analyses of exogenous gene expression and for pathological,scanning electron microscopic observation of thrombus.Thirty days later,the patency rates of remnant grafts(n=10) were recorded by vessel Doppler ultrasonography.Human TFPI gene products were detected in gene transferred vein grafts.Three days later,thrombi were found in 7 animals of aspirin control group and in 8 animals of empty plasmid control group,but in only 1 of TFPI group(P<0.01).Thirty days later,5 grafts were occluded in empty plasmid control group,but none of grafts was occluded in the other groups(P<0.05).The endothelial surfaces of grafts in both of the control groups were covered with aggregated erythrocytes and platelets,and it were not seen in TFPI group.It was suggested that the anticoagulant effects on vein grafts of human TFPI gene trans-fection are better than those of aspirin.     

Effects of Livin gene RNA interference on apoptosis of cervical cancer Hela cells and enhanced sensitivity to cisplatin

The recombinant plasmids pGenesil-1-BIRC71 and pGenesil-1-BIRC72 were transfected into Hela cells and cisplatin was added with different concentrations in order to study the inhibitory effects of Livin gene, increase the apoptosis induced by cisplatin, and detect the expression ofBcl-2, Bax, caspase-3, and survivin genes. The pGenesil-1-BIRC71 and pGenesil-1-BIRC72 were transfected into Hela cells, and the expression levels of Livin, Bcl-2, Bax, caspase-3, and survivin genes were detected by using fluorescence quantitative real-time PCR. Then cisplatin at different concentrations （3.0, 6.0 and 9.9 μg/mL） was added into the transfected Hela cells, and 24, and 48 h later, the apoptosis rate was measured by flow cytometry. After transfection of pGenesil-l-BIRC71 and pGenesil-1-BIRC72 into Hela cells, the expression level of Livin gene was obviously reduced, and the apoptosis rate was significantly increased in transfection group as compared with control group （P〈0.05）. Cisplatin could increase the apoptosis rate in a dose- and time-dependent manner. After cisplatin was added, the expression levels of Bcl-2 mRNA were reduced, and those of Bax, caspase-3, and survivin mRNA were increased in transfection group as compared with those in control group （P〈0.05）. It was concluded that shRNA expression vector targeting Livin gene could inhibit the expression of Livin gene in Hela cells and enhance the apoptosis induced by cisplatin, which was related to the decreased expression of Bcl-2 and activation of Bax and caspase-3. Survivin might play an important role as an antagonist in the process of apoptosis induction.     

Experimental study on MyoD gene induced differentiation of bone marrow mesen-chymal stem cells into myoblasts in vitro

Objective: To explore the possibility of the transfection of MyoD gene induced bone marrow mesenchymal stem cells ( MSCs) to differentiate into myoblasts in vitro. Methods: The eukaryotic expression plasmid vector pIRES2-EGFP-MyoD was transfected into MSCs with lipotransfection method, and the positive cells were selected by G418; The expression of MyoD was detected in the transfected MSCs with RT-PCR and the amplified, purified product was identified by sequencing; The reporter gene enhanced green fluorescence protein ( EFGP) was observed in the transfected cells under a fluorescent and a laser confocal microscopes; Immunohistochemical methods was used to examine the expressions of MyoD, myogenin, myosin, myoglobin and desmin in the differentiated cells. The ultrastructure changes of the cells before and after transfection were observed with electron microscopy. Results: The expression of MyoD was detected in the transfected MSCs with RT-PCR and the amplified, purified product was as same in sequence a     

Adenovirus-mediated TGF- β1 gene transfer to human degenerative lumbar int ervertebral disc cells

Objective To test the possibility of modification of human degenerative lumbar disc cells by the exogenous growth factor gene, transforming growth factor β(1) (TGF- β 1) cDNA, and the expression of the encoded protein. Methods Nucleus pulposus samples were surgically obtained from 8 patients with degenerat ive lumbar disc disease. The cells were cultured and directly infected by two a denoviral constructs, Ad/CMV- EGFP containing the enhanced green fluorecence pro tein (EGFP) gene (marker gene) and Ad/CMV- TGF- β(1) containing the potentially therapeutic TGF- β(1) gene. Transgene expression was analyzed by fluorescence production and immunohistochemical staining (Ad/CMV- TGF- β(1)). Results Culture cells transducted by Ad/CMV- EGFP showed specific green fluorescence und er the fluoroscope and expression sustained for at least 4 weeks. When infe cted by Ad/CMV- TGF- β(1), approximally 30% of cultured cells were staind brown (+) with TGF- β(1) staining. Conclusion This study established the strategy of delivering a potentially therapeutic gene , TGF- β(1), by using an adenoviral vector to human degenerative lumbar interve rtebral disc cells.     

Construction of Smac gene-carrying and human uroplakin Ib promoter-Regulated Genetic Vector and its Expression

Objective： To construct an eukaryotic expression vector that contains Smac gene, which is regulated by human Uroplakin Ib （UpIb） promoter. Methods： For the directionality of Smac expression in the transitional cell carcinoma of bladder, internal CMV and T7 promoter sequences in eukaryotic expression vector pcDNA3.1-Smac were replaced with UpIb promoter to construct a new plasmid. The plasmid DNA was identified by gel electrophoresis after being double digested at respective sites, and then the sequence was analyzed. The expression of Smac mRNA and protein in BIU87 cell line were detected after the transfection by using the newly constructed vector. Results： The Smac gene-carrying and UpIb promoter-regulated eukaryotic expression vector pcDNA3-UpIb-promoter-Smac was successfully constructed. The expression of Smac mRNA was approximately increased by 2.1 times and the expression of Smac protein was increased in about 71% BIU87 cells. Conclusion： The new vector can be effectively expressed in bladder cancer cells and be of great significance for bladder cancer-targeted gene therapy.     

纳米粒子介导特异基因转染的实验研究

目的：观察纳米粒子携带特异性基因转染的可行性及其效率,方法：应用聚乳酸聚乙醇酸共聚物和聚乙烯醇包载特异性反义单核细胞趋化蛋白－1基因,制备纳米级粒子混合物。检测其包埋率,体外释放情况及粒度。以阳离子脂质体为对照,利用培养的平滑肌细胞,应用聚合酶链反应（PCR）观察其为真核细胞传递基因的可能性。采用移植静脉内膜增生动物模型,应用RNA斑点杂交和病理形态学分析。观察其在体内的基因转染、表达及生物学效应。结果：制备的纳米粒子－DNA粒度为150－300nm,包埋率为：0．9％,体外释放时间为2周左右。PCR结果提示：纳米粒子可将目的基因转移至平滑肌细胞中,体内实验显示：纳米粒子可实现体内局部基因转染,表达,发挥相应的效应。结论：纳米粒子可用于特异性基因的转染。     

纳米粒子作为基因载体在不同动物模型上的基因转染效果

目的验证包载反义单核细胞趋化蛋白-1(A-MCP-1)质粒的聚乳酸聚乙醇酸共聚物(PLGA)纳米粒子在不同动物模型上的基因转染效果。方法采用乳化溶剂挥发法制备A-MCP-1纳米粒子并进行体外物化表征。用血管平滑肌细胞进行体外基因转染,PCR法检测其转染效果。兔移植静脉内膜增生模型和大鼠腹主动脉瘤模型体内局部给予A-MCP-1纳米粒子,应用病理形态学分析、斑点杂交、原位杂交、Western blot等方法观察其在体内的基因转染效果和对内源性MCP-1基因表达的抑制作用。结果基因纳米粒子平均粒径为201·4nm,基因含量为4·14%,基因的包封效率为86%,体外可维持稳定释放两周以上。兔移植静脉内膜增生基因纳米粒子组的动脉组织中检测到明显的A-MCP-1表达,并抑制了正义MCP-1表达,内膜/中膜比为0·56±0·06,与对照组比较差异具有显著性(P<0·05),与阳离子脂质体1,2-二油酰-3-三甲铵基丙烷(DOTAP)诱导的A-MCP-1质粒组比较,差异无显著性。大鼠腹主动脉瘤模型体内转染2周后,基因纳米粒子组腹主动脉直径为(1·79±0·12)mm,明显小于空白纳米粒子悬浮液组(2·58±0·21)mm和生理盐水组(2·63±0·29)mm(P<0·01)。MCP-1基因的mRNA和蛋白表达水平分别为12·5±1·5,17·6±2·1,明显低于空白纳米粒子悬浮液组35·7±4·5,42·3±5·7(P<0·01),生理盐水组32·4±3·9,39·8±4·8(P<0·01)。结论A-MCP-1基因纳米粒子用于兔移植静脉内膜增生模型以及大鼠腹主动脉瘤模型成功实现基因转染的研究结果,显示了其应用于临床的巨大潜力。     

定点整合型基因治疗腺病毒载体的构建

目的：构建定点整合型基因治疗腺病毒载体。方法：以逐步亚克隆法将腺病毒伴随病毒的两个末端倒转重复序列与neo基因表达盒克隆至pAdE1CMV，其中HCMV启动子控制下的neo基因表达盒位于腺病毒伴随病毒两个末端倒转重复序列之间，将得到的转移载体pAdE1CMVITREXneoDNA和pJM17DNA以脂质体法共转染293细胞，G418法连续筛选重组腺病毒。以病毒核酸酶切及感染293细胞的CPE（cytopathiceffect　）观察鉴定是否获得重组腺病毒。结果：获得有腺病毒伴随病毒的两个末端倒转重复序列和位于其间的neo基因表达盒的重组腺病毒vAd－AAV。结论：重组腺病毒vAd－AAV的构建成功将为基因治疗提供定点整合型腺病毒载体。     

MCP-1siRNA真核表达载体的构建及其对HKCMCP-1基因沉默效应的鉴定

目的构建单核细胞趋化蛋白1(MCP-1)特异性小分子干扰RNA(siRNA)的真核表达载体,研究siRNA对人肾小管上皮细胞(HKC)MCP-1基因的沉默作用。方法采用基因克隆技术,将合成的MCP-1特异性siRNA插入真核表达载体pRNAT-U6/Neo中,构建MCP-1 siRNA真核表达载体。将pRNAT-MCP-1质粒以脂质体法转染HKC,24 h后应用实时定量RT-PCR技术检测HKC内MCP-1 mRNA水平的表达情况。结果成功构建MCP-1siRNA真核表达载体,转染MCP-1 siRNA的HKC,24 h后HKC内MCP-1 mRNA水平表达明显降低,抑制效率达90%以上。结论构建的RNA干扰真核表达载体能够高效抑制HKC的MCP-1基因表达,为肾间质纤维化的防治研究奠定了实验基础。     

兔自体移植静脉基因转移模型的建立

兔颈动脉－颈表脉帝路手术后，将阳离子指质体ＤＯＳＰＥＲ介导的ｐ５３腺相关病毒增强型质粒表达载体，经腔内加压灌注转染移植静脉。ＲＴ－ＰＣＲ和免疫组化检测证明，外源性ｐ５３基因在移植血管中表达出相应的ｍＲＮＡ及ｐ５３蛋白。结果提示：腔内加压灌注是移植静脉基因转移的有效方法之一。     

核因子κB的小干扰RNA防治自体移植静脉再狭窄的实验研究

目的   探讨核因子κB（NF-κB）的小干扰RNA（small interfering RNA,siRNA)对大鼠自体静脉移植术后血管内膜增殖及相应炎性细胞因子表达的影响。方法    雄性Wistar大鼠80只,随机分为空白组（A组,n=10）;自体静脉移植组（B组,n=18）;空载体组（阴性质粒脂质体医用蛋白胶复合物转染移植静脉,C组,n=26）和基因转染组（NF-κB siRNA阳离子脂质体医用蛋白胶复合物转染自体移植静脉,D组,n=26）。B、C及D组需制作大鼠自体颈外静脉——腹主动脉移植模型,每组4个时点( 3,7,14,21d),相应时间点取移植静脉观察病理形态学变化,免疫组化检测增殖细胞核抗原（PCNA）,PCR测定单核细胞趋化因子（MCP-1）和肿瘤坏死因子-α（TNF α）的mRNA含量,Western blot测定NF-κB p65蛋白的表达。结果    自体静脉移植术后,B、C和D组移植静脉血管桥均出现内膜增生变厚,新生内膜有大量PCNA阳性细胞,中膜平滑肌细胞增生活跃。术后3d,B组和C组 MCP-1 mRNA及TNF-αmRNA表达水平明显高于A组（P＜0.05）,但D组水平明显低于C组（P＜0.05）。术后7d,B、C组NF-κB p65蛋白表达水平明显高于A组（P＜0.05）,与C组相比,D组NF κB p65蛋白水平明显降低（P＜0.05）。结论     NF-κB的基因表达产物和MCP-1mRNA、TNF-αmRNA的表达有一定相关性,自体静脉移植术后新生内膜增生及炎性细胞因子表达在不同时相点呈动态变化。转染NF-κB siRNA阳离子脂质体复合物可抑制NF-κB的表达,减少MCP-1及TNF-αmRNA的表达,从而抑制移植静脉内膜增生和VSMC增殖,减轻再狭窄。     

两种方法介导外源基因稳定转染大鼠肝癌细胞株的有效性及其对细胞生长影响的比较

目的探讨磷酸钙共沉淀法与阳离子脂质体试剂形成复合物法两种基因转染方法构建大鼠肝癌细胞克隆株的有效性及对生长影响的比较。方法将携带增强型绿色荧光蛋白的真核表达载体pEGFP-N1分别用脂质体形成复合物法、磷酸钙共沉淀法导入大鼠肝癌CBRH-7919细胞,G418筛选基因稳定转染阳性单细胞克隆株。RT-PCR法检测EGFP基因在细胞中的表达。结果两种方法转染CBRH-7919细胞24h后,倒置相差荧光显微镜下观察均见绿色荧光。G418加压筛选14d后均形成阳性克隆,倒置相差荧光显微镜下可见绿色荧光,脂质体法的细胞克隆荧光强度强于磷酸钙。阳性克隆株经RT-PCR法检测,750bp于450bp处均有特异性条带。结论两种细胞转染方法均可使增强型绿色荧光蛋白基因稳定转染CBRH-7919,为今后探讨外源目的基因对靶细胞生长特性的影响奠定前期实验基础。     

脂质体介导外源性基因在骨髓基质细胞表达

目的：用阳离子脂质体介导真核表达载体pEGFP-PDX-1转染大鼠骨髓基质细胞，并对其转染条件进行优化以获得较高效率。方法：构建的重组载体鉴定后，以脂质体介导其转染骨髓基质细胞,改变DNA,脂质体的量,在荧光显微镜下观察荧光并计算转染效率；转染后48 h进行细胞免疫组化染色检测目的基因的表达情况。结果：限制性酶切分析证实重组后的载体成功载入PDX-1基因；克隆的目的片断经序列测定与GenBank公布的序列一致；质粒∶脂质体为1∶1或1∶2的转染效率最佳；细胞免疫化学染色检测证实转染后骨髓基质细胞有PDX-1基因表达。结论：成功构建了含有PDX-1基因的真核表达载体；通过优化转染条件提高了pEGFP-PDX-1转染大鼠骨髓基质细胞的效率,为成为组织工程的种子细胞提供了实验依据。     

Effects of extravascular trestle model coated phosphorus radioisotope on intimal hyperplasia in autologous vein grafts

Objective: To design an extravascular trestle model coated phosphorus-32, an isotope radiating beta rays,and investigate its effects on intimal hyperplasia of autologous vein grafts. Methods: ETA cDNA was used as a geneprobe specific to vascular SMCs on the basis of in situ hybridization. The femoral veins were transplanted reversely intocolateral femoral arteries in rabbits, and the animals were divided into control, chemical agents and phosphorus-32groups. The morphometry was applied to calculate the ETA cDNA expression and intimal thickness. Spearman correla-     

反义VEGF基因转染对HEP-2细胞生物学行为的影响

目的观察反义VEGF基因转染对HEP-2细胞生物学行为的影响.方法克隆人VEGF基因,将VEGF-cDNA反向克隆到真核表达载体pcDNA3,构建反义VEGF表达载体pcDNA3-VEGF(-);利用阳离子脂质体载体,稳定转染人喉癌Hep-2细胞,并通过流式细胞仪检测,观察转染细胞细胞周期的改变,在透射电镜下观察转染细胞超微结构的改变;将转染细胞注入裸鼠皮下,观察肿瘤生长情况.结果成功克隆了人VEGF基因,并构建了携带反义VEGF基因的真核表达载体pcDNA3-VEGF(-);将其稳定转染人喉癌Hep-2细胞,获得了稳定表达反义VEGF的细胞系,与正常Hep-2细胞相比,该细胞系细胞周期及超微结构均无明显改变;将转染细胞注入裸鼠皮下,与对照组相比,肿瘤的生长速度明显减缓.结论反义VEGF基因转染可以有效地抑制喉癌的生长.