siRNA抑制survivin基因及其对人肝癌细胞株HepG2细胞凋亡的影响

目的观察特异小干扰RNA（small interfering RNA,siRNA）抑制survivin基因表达对人肝癌细胞株HepG2细胞凋亡的影响。方法构建survivin-siRNA真核表达载体,利用脂质体转染人肝癌HepG2细胞,采用反转录聚合酶链反应（RT-PCR）技术检测survivin基因mRNA表达水平。针对转染后不同的时间点采用四甲基偶氮唑蓝（MTT）法检测各组细胞的增殖以及HepG2细胞的凋亡情况。结果构建的survivin-siRNA转染组survivin蛋白表达较对照组明显下调,差异有显著性（P〈0.01）,其增殖能力较对照组显著下降（P〈0.001）;而阳性对照组及未转染组对survivin表达及mRNA抑制作用不明显（P=0.219）。结论所构建的针对人survivin-siRNA可显著抑制survivin的表达及HepG2细胞凋亡。     

siRNA腺病毒抑制Survivin基因表达诱导肝癌细胞凋亡

目的为改进质粒siRNA载体的不足,建立siRNA的病毒性载体系统,并探讨凋亡抑制因子Survivin基因在肝癌细胞中的作用。方法通过已建立的Survivin质粒siRNA,构建Survivin的腺病毒siRNA载体系统,筛选重组病毒并感染肝癌细胞HepG2细胞,应用Western blot和RT-PCR检测Survivin基因表达变化,用流式细胞仪观察肿瘤细胞凋亡。结果成功构建Survivin基因的腺病毒siRNA载体及重组腺病毒,感染肝癌细胞明显抑制Survivin蛋白表达,抑制率66.32%;降低Survivin基因的mRNA转录水平达72.04%;应用流式细胞仪观察肿瘤细胞凋亡明显增加。结论腺病毒siRNA载体系统可作为抑制目的基因,进而研究其功能和作用的技术平台,并为其他基因的相关研究打下基础;抑制Survivin基因表达可诱导肿瘤细胞HepG2的凋亡,为今后腺病毒siRNA载体应用于肿瘤动物实验和肿瘤基因治疗提供实验资料。     

RNA介导survivin基因沉默对肝癌细胞HepG2细胞株凋亡及增殖的影响

目的观察靶向封闭survivin基因对肝癌细胞株HepG2增殖和凋亡的影响,探讨survivin基因在肝癌的发生、发展中的作用。方法设计1对survivin-siRNA,体外转录制备siRNA。应用脂质体转染技术将survivin-siRNA转染肝癌细胞株HepG2,应用有荧光标记的非特异性小分子siRNA检测转染效率;RT-PCR检测survivin-mRNA水平;SABC免疫组化染色技术检测survivin蛋白表达情况;MTT法检测细胞生长情况;流式细胞仪分析细胞凋亡。结果转染survivin-siRNA可使HepG2细胞survivin-mRNA水平下降53.8%,并可使survivin蛋白表达明显减少;转染survivin-siRNA对细胞增殖及细胞凋亡无明显影响(P>0.05)。结论抑制survivin表达对肝癌细胞株HePG2凋亡及增殖无明显影响。提示survivin在肝癌细胞增殖与调亡调控中所起的作用可能并非是关键性的。     

Survivin靶向RNA干扰对人结肠癌HCT116细胞生长影响的研究

目的设计和构建survivin特异性的siRNA真核表达载体,观察survivin siRNA重组体对人大肠癌HCT116细胞株生长的影响,为大肠癌的基因治疗提供理论依据。方法针对survivin mRNA序列设计合成编码siRNA的DNA模板,构建2个survivin RNAi真核表达载体;实验分为survivin siRNA重组质粒转染组、空载体组和HCT116组,转染大肠癌细胞HCT116细胞,采用RT-PCR法检测survivin mRNA的表达,观察重组质粒对转染的HCT116细胞survivin基因表达的影响;用四甲基偶氮唑盐（MTT）法测量细胞生长情况;用流式细胞术检测细胞凋亡情况。结果测序表明survivin干扰序列完全正确,RT-PCR结果显示2条survivin siRNA真核表达质粒均能有效抑制survivin mRNA的转录表达。MTT比色法检测显示,与阴性对照组及未转染组细胞比较,干扰组细胞增殖率明显下降（P〈0．05）。流式细胞术检测的转染重组质粒组细胞凋亡率高于脂质体对照组和空质粒对照组（P〈0．05）。结论成功构建了survivin干扰真核表达载体,siRNA重组体能有效抑制人大肠癌细胞survivin mRNA表达,并抑制结肠癌细胞生长,促进其凋亡。     

siRNA沉默STAT3基因对人肝癌细胞的抑制及对相关生长调控基因的调节

目的: 探讨RNA干扰技术沉默STAT3基因表达对人肝癌细胞的抑制作用及对相关生长调控基因的调节.方法:构建pSilencer 3.0-H1-siRNA-STAT3重组质粒, 转染人肝癌细胞株SMMC 7721, 采用MTT法观察重组质粒对肝癌细胞的生长抑制, RT-PCR和Western blot及免疫组化法分别观察STAT3基因和蛋白水平的变化, 同时检测 survivin, c-myc, VEGF, p53, caspase3生长调控基因的mRNA, 并用流式细胞技术(FCM)及AO/EB染色方法观察细胞凋亡.结果: pSilencer 3.0-H1-siRNA-STAT3重组质粒对肝癌细胞的生长有抑制作用, 实验组48 h和72 h抑制率分别为59.32%, 76.49%, 与空白组及阴性组细胞相比有显著性差异(P<0.01);在重组质粒组, STAT3基因mRNA及蛋白水平表达降低, surviving, VEGF的mRNA表达下调, p53, caspase3的mRNA表达上调(P<0.01), c-myc的mRNA表达却无明显改变;重组质粒可诱导SMMC 7721细胞凋亡, 凋亡率达21.6%(P<0.01), 细胞周期分析显示细胞阻滞于G2期.结论:pSilencer 3.0-H1-STAT3-siRNA可能通过下调基因survivin和VEGF mRNA表达, 上调p53和caspase3 mRNA表达来抑制STAT3基因在人肝癌细胞中的表达.     

RNAi沉默Polo-like kinase-1基因表达对胰腺癌细胞增殖的影响

目的:探讨polo-like kinase-1(PLK1)基因在胰腺癌细胞中的作用.方法:采用PLK1小干扰核糖核酸分子(small interfering RNA,siRNA)转染人胰腺癌Mi- aPaCa-2细胞后,分别采用实时定量PCR和Western blot检测PLK1基因mRNA和蛋白表达水平,观察PLK1 siRNA转染对胰腺癌细胞体内外增殖的影响.于转染不同时间后收集细胞,分别采用琼脂糖凝胶电泳和TUNEL方法检测胰腺癌细胞凋亡情况.结果:胰腺癌MiaPaCa-2细胞经siRNA转染处理后,PLK1 mRNA和蛋白表达水平明显下降(P<0.05).PLK1基因siRNA可明显抑制癌细胞体外生长(P<0.05)和体内裸鼠模型增殖(P<0.05).细胞凋亡检测发现,DNA电泳出现明显的梯度图谱,且与浓度相关(r=0.836,P<0.05).TUNEL结果显示,转染组癌细胞凋亡指数明显增加,且呈时间和浓度依赖性(r= 0.875,P<0.05).结论:PLK1 siRNA转染可明显抑制胰腺癌细胞增殖,其机制可能与诱导细胞凋亡有关.     

Identification of effective siRNA against K-ras in human pancreatic cancer cell line MiaPaCa-2 by siRNA expression cassette

AIM: We shall construct the small interfering RNA (siRNA) expression cassette (SEC) targeting activated K-ras gene sequence, identify more effective siRNA sequence against K-ras gene in human pancreatic cancer cell line MiaPaCa-2 by SEC and reveal the anti-cancer effects of RNA interference (RNAi) and its therapeutic possibilities. METHODS: Three different sites of SECs were constructed by PCR. K1/siRNA,K2/siRNA and K3/siRNA are located at sites 194,491 and 327, respectively. They were transfected into MiaPaCa-2 cells by liposome to inhibit the expression of activated K-ras. In the interfering groups of sites 194 and 491, we detected the apoptosis in cells by FACS after they were incubated for 48 h, then we tested the alternation of K-ras gene in MiaPaCa-2 cells by RT-PCR immunofluorescence, respectively. RESULTS: Introduction of the Kl/siRNA and K2/siRNA against K-ras into MiaPaCa-2 cells leads to increased apoptosis, and the number of apoptotic cells is increased compared with control cells. The tests of RT-PCR immunofluorescence show the effects of inhibiting expression of activated K-ras gene by RNA interference in the Kl/siRNA and K2/siRNA groups. We also find that the introduction of K3/siRNA has no effect on MiaPaCa-2 cells. CONCLUSION: Kl/siRNA and K2/siRNA can inhibit the expression of activated K-ras but K3/siRNA has no effect, demonstrating that Kl/siRNA and K2/siRNA are effective sequences against K-ras gene and K3/siRNA are not. We conclude that specific siRNA against K-ras expression may be a powerful tool to be used therapeutically against human pancreatic cancer.     

抑制Survivin表达对胰腺癌细胞凋亡的影响

目的 探讨以Survivin为靶基因的胰腺癌基因治疗的可能性,为胰腺癌基因治疗提供依据.方法 采用化学合成的小十扰RNA(siRNA)和pGCSi载体中的小发夹RNA(shRNA)抑制胰腺癌细胞系PaTu8988的Sunrivin基因表达,通过观察胰腺癌细胞株Survivin基因表达的下调以及细胞形态、细胞凋亡、细胞活力、凋亡信号途径等的改变评价Survivin作为靶基因的治疗效果.结果 不同序列的siRNA和shRNA抑制胰腺癌细胞Survivin的表达后,Survivin mRNA和蛋白表达水平明显下降(P<0.05);碘化吡啶(PI)染色法观察发现RNA干扰(RNAi)后细胞出现核皱缩、细胞凋亡率>20%;流式细胞仪检测发现RNAi后在G0/G1期前出现了亚二倍体峰(P<0.05);Western blot法检测发现RNAi后Casptrqe-3被激活(P<0.05).结论 通过抑制胰腺癌细胞PaTu8988的Survivin表达可以诱导肿瘤细胞启动凋亡程序,加速肿瘤细胞凋亡,由此可望提高胰腺癌的治疗效果.     

Knockdown of survivin gene expression by RNAi induces apoptosis in human hepatocellular carcinoma cell line SMMC-7721

AIM: To investigate the survivin gene expression in human hepatocellular carcinoma cell line SMMC-7721 and the effects of survivin gene RNA interference (RNAi) on cell apoptosis and biological behaviors of SMMC-7721 cells. METHODS: Eukaryotic expression vector of survivin gene RNAi and recombinant plasmid pSuppressorNeo-survivin (pSuNeo-SW), were constructed by ligating into the vector, pSupperssorNeo (pSuNeo) digested with restriction enzymes Xba I and Sail and the designed double-chain RNAi primers. A cell model of SMMC-7721 after treatment with RNAi was prepared by transfecting SMMC-7721 cells with the lipofectin transfection method. Strept-avidin-biotin-complex (SABC) immunohistochemical staining and RT-PCR were used to detect survivin gene expressions in SMMC-7721 cells. Flow cytometry was used for the cell cycle analysis. Transmission electron microscopy was performed to determine whether RNAi induced cell apoptosis, and the method of measuring the cell growth curve was utilized to study the growth of SMMC-7721 cells before and after treatment with RNAi. RESULTS: The eukaryotic expression vector of survivin gene RNAi and pSuNeo-SW, were constructed successfully. The expression level of survivin gene in SMMC-7721 cells was observed. After the treatment of RNAi, the expression of survivin gene in SMMC-7721 cells was almost absent, apoptosis index was increased by 15.6%, and the number of cells was decreased in G2/M phase and the cell growth was inhibited. CONCLUSION: RNAi can exert a knockdown of survivin gene expression in SMMC-7721 cells, and induce apoptosis and inhibit the growth of carcinoma cells.     

Downregulation of alpha-fetoprotein siRNA inhibits proliferation of SMMC-7721 cells

AIM: To study the function of α-fetoprotein (AFP) in SMMC-7721 hepatoma cells. METHODS: A hairpin siRNA expressing plasmid pSilencer3.0-H1-afp was constructed and transfected into SMMC-7721 cells with Lipofectamine 2000. The expression of AFP was monitored by real-time RT-PCR and immunoassays, its effect on SMMC-7721 cell proliferation and cell death was detected by MTT and fluorescenceactivated cell sorter (FACS). RESULTS: The AFP-siRNA expressing plasmid downregulated the expression of AFP obviously (about 34%), and inhibited SMMC-7721 cell proliferation, but did not induce apoptosis. CONCLUSION: Downregulation of AFP siRNA inhibits proliferation of SMMC-7721 cells, but cannot cause apoptosis.     

生存素基因突变体诱导胃癌细胞有丝分裂障碍的实验研究

目的 观察生存素基因突变体质粒(Cys84Ala)对胃癌细胞有丝分裂过程中细胞动力学行为的影响。方法 应用基因重组技术构建Cys 84 Ala，以脂质体转染的方法将质粒DNA转入胃癌细胞株，应用免疫组化法检测胃癌组织中生存素基因表达，流式细胞仪检测胃癌细胞凋亡及细胞周期，Western blot检测胃癌细胞中多聚ADP核糖聚合酶(PARP)和细胞色素C蛋白的表达，免疫荧光染色检测有丝分裂危象情况。结果 Cys84Ala可通过抑制野生型生存素基因的功能诱导胃癌细胞凋亡，增加caspase-3活性，促进PARP裂解和细胞色素C的释放，亦可导致胃癌细胞发生有丝分裂障碍而死亡。结论 cys84Ala能通过不同的途径诱导胃癌细胞凋亡和有丝分裂危象，并有可能成为胃癌治疗的一个候选基因。     

siRNA沉默AFP基因对肝癌细胞系EGHC-9901凋亡的影响

目的建立稳定表达针对AFP基因siRNA质粒的肝癌细胞模型并探讨对其凋亡的影响。方法构建针对AFP基因的siRNAs表达质粒,脂质体法将该质粒转染肝癌细胞系EGHC-9901,G418筛选4~5周后Western blot及RT-PCR检测靶基因抑制效果,细胞分组：实验组（siRNA-afp）,转染AFP-siRNA质粒组;载体对照组,转染空载体组;空白对照组,未做任何处理组。免疫荧光检测细胞在无血清状态下凋亡情况,Western blot及RT-PCR检测Caspase-3、Caspase-8等凋亡相关蛋白表达。结果在体外成功构建针对AFP的siRNA表达质粒并在体外建立稳定表达该质粒肝癌细胞系EGHC-9901,转染后细胞表达AFP近乎完全抑制;免疫荧光表明促进细胞在无血清状态下的实验组凋亡率为32%±4%,对照组凋亡率为17%±3%,差异有统计学意义（P〈0.05）;RT-PCR及Western blot检测凋亡相关蛋白表明实验组Caspase-3表达较对照组高,差异有统计学意义（P〈0.05）,而Caspase-8、Caspase-9、bcl-2表达无显著差异（P〉0.05）。结论在体外成功建立稳定表达针对AFP基因的siRNA肝癌细胞系,抑制AFP表达可能通过上调Caspase-3表达促进其凋亡。     

靶向cyclinE小干扰RNA对肝癌HepG2细胞增殖和凋亡的影响

目的:以cyclinE基因编码区为靶位,构建表达小干扰RNA(siRNA)的质粒载体,观察转染后对HepG2细胞的影响.方法:针对cyclinE基因序列构建表达siRNA的真核表达载体pSilencer3.1-H1hygro,利用脂质体Metafectene转染CyclinE基因高表达的肝癌细胞株HepG2.流式细胞仪检测细胞周期及凋亡率,MTT法检测细胞增殖活性,RT-PCR和Western blot法观察转染后细胞cyclinE基因表达.结果:成功构建了表达siRNA的真核质粒载体,转染后cyclinE基因mRNA及蛋白表达水平分别下降了79%和65%.结论:靶向cyclinE基因的siRNA可有效沉默HepG2细胞高表达的cyclinE基因,从而抑制肝癌细胞的增殖并促进凋亡.     

Survivin对人胆管癌细胞凋亡相关信号通路的作用机制

目的:探讨Survivin基因对人胆管癌细胞凋亡信号通路的调节机制.方法:构建针对Survivin基因的siRNA和对照siRNA,分别转染QBC939人胆管癌细胞,Western blot检测siRNA对细胞Survivin的干扰效果.继而分别用流式细胞仪,激酶活性测定和Westernblot检测不同Survivin表达状态下,QBC939细胞的凋亡状态,caspase-3的活性和caspase-3,caspase-9及procaspase-9凋亡信号分子的表达.结果:siRNA-Survivin显著抑制Survivin在QBC939细胞的表达(P<0.05).Survivin表达抑制后,QBC939细胞凋亡明显增加(18.9%±2.3%,P<0.05),caspase-3活性显著升高(0.83±0.15,P<0.01),caspase-3和caspase-9表达明显上调(P<0.05),而procaspase-9表达降低(P<0.05).未转染和转染对照siRNA的QBC939细胞上述变化无显著性差异(P>0.05).结论:Survivin基因通过促进procaspase-9的活化以阻止caspase-3和caspase-9的激活从而抑制胆管癌细胞的凋亡.     

Radiosensitivity of human colon cancer cell enhanced by immunoliposomal docetaxel

ABM: To enhance the radiosensitivity of human colon cancer cells by docetaxel. METHODS: Immunoliposomal docetaxel was prepared by coupling monoclonal antibody against carcinoembryonic antigen to cyanuric chloride at the PEG terminus of liposome. LoVo adenocarcinoma cell line was treated with immunoliposomal docetaxel or/and irradiation. MTT colorimetric assay was used to estimate cytotoxicity of immunoliposomal docetaxel and radiotoxicity. Cell cycle redistribution and apoptosis were determined with flow cytometry. Survivin expression in LoVo cells was verified by immunohistochemistry. D801 morphologic analysis system was used to semi-quantify immunohistochemical staining of survivin. RESULTS: Cytotoxicity was induced by immunoliposomal docetaxel alone in a dose-dependent manner. Immunoliposomal docetaxel yielded a cytotoxicity effect at a low dose of 2 nmol/L. With a single dose irradiation, the relative surviving fraction of LoVo cells showed a dose-dependent response, but there were no significant changes as radiation delivered from 4 to 8 Gy. Compared with liposomal docetaxel or single dose irradiation, strongly radiopotentiating effects of immunoliposomal docetaxel on LoVo cells were observed. A low dose of immunoliposomal docetaxel could yield sufficient radiosensitivity. Immunoliposomal docetaxel were achieved both specificity of the conjugated antibody and drug radiosensitization. Combined with radiation, immunoliposomal docetaxel significantly increased the percentage of G2/M cells and induced apoptosis, but significantly decreased the percentage of cells in G2/G1 and S phase by comparison with liposomal docetaxel. Immunohistochemical analysis showed that the brown stained survivin was mainly in cytoplasm of LoVo cells. Semi-quantitative analysis of the survivin immunostaining showed that the expression of survivin in LoVo cells under irradiation with immunoliposomal docetaxel was significantly decreased. CONCLUSION: Immunoliposomal docetaxel is strongly effective for target radiosensitation in LoVo colon carcinoma cells, and may offer the potential to improve local radiotherapy.