慢病毒载体介导siRNA对裸鼠移植人肺腺癌A549抑瘤作用的实验研究

目的研究慢病毒载体介导siRNA抑制survivin基因表达后对人肺腺癌A549细胞体内增殖能力的影响以及对裸鼠移植人肺腺癌的抑瘤活性。方法应用裸鼠成瘤实验测定致瘤能力的改变，采用RT-PCR和Western-blot测定干扰后survivin基因及其蛋白的表达水平；流式细胞术检测肺癌细胞凋亡指数和增殖指数。结果靶向survivin基因的siRNA可以有效抑制survivin基因的表达，使survivin-mRNA表达减少50％-80％，蛋白表达减少60％；流式细胞术检测细胞凋亡率明显提高（P〈0．01），降低了在裸鼠体内成瘤的能力。结论RNA干扰survivin基因表达后明显抑制了人肺腺癌A549细胞的体内增殖能力；siRNA介导的survivin基因下调可明显抑制肿瘤细胞在体内的生长。     

RNAi沉默CDC25a基因对人肝癌细胞HepG2裸鼠移植瘤的影响

目的:研究细胞分裂周期素25a(cell division cycle 25a,CDC25a)基因RNAi(RNA干扰)的重组慢病毒载体对人肝癌细胞Hep G2 CDC25a基因表达和裸鼠移植瘤生长的影响。方法:实验组以CDC25a基因重组慢病毒颗粒感染Hep G2细胞;阴性对照组以RNAi-NC慢病毒颗粒感染Hep G2细胞;空白对照组常规培养。三组细胞分别接种至裸鼠皮下,建立人肝癌裸鼠移植瘤模型。连续28 d观察裸鼠成瘤情况及移植瘤生长情况,28 d后测定肿瘤体积和重量。用RT-PCR、Western blot及免疫组织化学法检测移植瘤中CDC25a的表达情况。结果 :各组裸鼠接种Hep G2细胞后第7天均有肿瘤形成,实验组的肿瘤生长速度、体积和重量明显低于空白对照组和阴性对照组(P<0.05)。实验组瘤体中CDC25a的m RNA及蛋白表达与阴性对照组及空白对照组相比明显下降(P<0.05)。结论:LV-CDC25a-RNAi重组体沉默Hep G2细胞的CDC25a基因后能有效抑制人肝癌裸鼠移植瘤的生长,提示CDC25a基因可被认为是肝癌治疗的关键靶点。     

沉默Medl9对人乳腺癌裸鼠成瘤的影响

目的:通过观察慢病毒介导的siRNA沉默Med19基因对人乳腺癌裸鼠成瘤的影响.探讨Med19在乳腺癌发生发展中的作用.方法:利用前期已稳定感染Med19-siRNA慢病毒载体的人乳腺癌MCF-7细胞.采用western blotting方法检测Med19蛋白的沉默效果.稳定感染Med19-siRNA慢病毒栽体的人乳腺癌MCF-7细胞接种于BALB/c裸鼠背侧皮下,观察裸鼠成瘤情况和移植瘤生长情况,并绘制生长曲线.以慢病毒空载体感染组作为阴性对照组.结果:所构建的Med19-siRNA慢病毒载体能有效抑制MCF-7细胞Med19蛋白的表达,蛋白表达水平下降了62%,Med19基因沉默组较空载体慢病毒感染组瘤体生长速度慢(t值分别为4.843、6.291、5-317,均p<0.01),肿瘤终体积分别为(620.08±263.07)mm3和(1 406.77±351.14)mill3,终重量分别为(0.20±0.18)g和(0.67±0.27)g,差异有统计学意义(t值分别为4.399、3.615,均P<0.01).结论:Med19基因沉默能有效抑制人乳腺癌裸鼠成瘤和移植瘤生长,表明 Med19在乳腺癌发生发展中起到重要作用,并有可能成为乳腺癌靶向治疗的潜在靶点.     

RNA干扰survivin基因在EC109细胞中作用的体内实验研究

目的研究RNA干扰survivin基因对EC109细胞体内增殖的影响。方法构建siRNA-survivin真核表达载体,转染EC109细胞,筛选得到稳定细胞克隆。同时设非特异siRNA载体转染为对照;通过裸鼠移植瘤模型的成瘤时间、瘤结节重量,比较各组细胞在体内的增殖速度;免疫组织化学染色检测移植瘤的细胞凋亡。结果siRNA-survivin转染的EC109细胞组在裸鼠体内成瘤时间为(8.86±1.069)d,高于其它各组;平均瘤重为(0.32±0.12)g,低于其它组,均有显著差异(P<0.05);TUNEL法细胞凋亡检测,siRNA-survivin转染的EC109细胞组的凋亡指数为(10.52±4.35),高于其它组,具有显著性差异(P<0.05);结论RNA干扰survivin基因具有抑制人食管癌EC109细胞体内增殖的作用,诱导细胞的凋亡是其重要作用机制。     

siRNA沉默细胞周期相关激酶基因对鼠结肠癌生长及其细胞凋亡的影响

目的探讨siRNA沉默细胞周期相关激酶(CCRK)基因对鼠结肠癌生长及其凋亡的影响。 方法将50只BALB/C(nu/nu)裸鼠皮下接种人类结肠癌SW480细胞,将其中建立移植瘤裸鼠模型成功的30只裸小鼠按照单纯随机抽样方法随机分为3组,分别接种siRNACCRK转染的人类结肠癌SW480细胞株(实验组)、正常培养的SW480细胞(空白对照组)和以转染携带无关序列片段sh RNA慢病毒的SW480细胞(阴性对照组)。第42天处死裸鼠后取下肿瘤组织,比较各组肿瘤重量、CCRKmRNA表达量、CCRK蛋白表达和细胞凋亡的变化。 结果转染siRNA组肿瘤重量、CCRK mRNA和CCRK蛋白表达[(0.54±0.15)g,1.14±0.24和0.18±0.05]表达显著低于空白对照组[(1.05 ± 0.14)g,2.41±0.42和0.49±0.07]和空siRNA载体组[(1.07 ±0 .12)g,2.39±0.47,0.47±0.09;F＝21.18,23.47,90.03;P<0.01];空白对照组与空siRNA载体组比较差异无统计学意义(q＝0.98,1.07,1.13;P>0.05)。实验组沉默CCRK基因后组织中细胞凋亡率为(21.23±1.12)%,明显高于空白对照组(6.78±0.37)%和阴性对照组(7.25±0.32)%,差异有统计学意义(F＝56.936,P<0.01);但空白对照组和空siRNA载体组之间差异无统计学意义(q＝1.78,P>0.05)。 结论CCRK靶向siRNA表达载体接种结肠癌裸鼠后能显著降低结肠癌瘤体的增长,抑制CCRK基因和蛋白表达;siRNA沉默CCRK基因能促进其凋亡,CCRK基因有望成为结直肠癌治疗的新靶点。     

ShRNA靶向沉默VEGFR1基因对U937细胞增殖、迁移和凋亡的影响

目的 探讨慢病毒载体介导shRNA(short harpin RNA,siRNA前体)靶向沉默血管内皮生长因子受体1(VEGFR-1)基因对U937细胞增殖、迁移和凋亡的影响.方法 构建针对VEGFR-1基因干扰序列和无关序列的shRNA慢病毒载体,与慢病毒包装质粒通过脂质体转染293T细胞,包装产生的病毒液感染U937细胞(U937-shVEGFR-1 KD组).采用实时荧光定量PCR、Western blot法检测RNA干扰对U937细胞VEGFR-1 mRNA和蛋白表达的影响;ELISA法检测细胞培养上清液VEGF表达水平的变化;CCK-8法检测常规培养条件下和不同浓度阿糖胞苷(Ara-C)作用下细胞增殖率和抑制率变化;流式细胞术检测经Ara-C作用后细胞凋亡率变化;Transwell小室检测不同条件下细胞迁移数量的变化.结果 成功构建VEGFR-1基因shRNA慢病毒载体,转染U937细胞后,U937-shVEGFR-1 KD组细胞VEGFR-1 mRNA和蛋白表达均显著下降;细胞培养上清液VEGF表达水平明显下降,细胞增殖速度减慢;Ara-C作用下,U937-shVEGFR-1 KD组细胞增殖抑制率及凋亡率较U937无关序列shRNA阴性对照(NC)组和U937空白对照(CON)组细胞明显增高.无药物及VEGF作用下,U937-shVEGFR-1 KD组细胞迁移数量均低于U937 NC组和U937 CON组细胞;Bevacizumab作用下,U937 NC组和U937 CON组细胞迁移数量降低,而U937-shVEGFR-1 KD组细胞迁移数量无明显变化.结论 慢病毒载体介导的shRNA干扰VEGFR-1基因可有效抑制U937细胞增殖、迁移,并能够增强U937细胞对Ara-C的敏感性.     

Xklp2靶蛋白对肺癌细胞裸鼠成瘤能力的影响及机制研究

目的探讨Xklp2靶蛋白(TPX2)对肺癌细胞裸鼠成瘤能力的影响及机制。方法慢病毒感染肺癌细胞A549,以感染TPX2小干扰RNA(siRNA TPX2)和siRNA阴性对照慢病毒的细胞作为siRNA TPX2组和siRNA-NC组,同时以不做处理的细胞为Control组,RT-PCR和Western blot检测感染后细胞中TPX2水平,噻唑蓝(MTT)检测细胞增殖,流式细胞术检测细胞凋亡,将各组细胞接种到裸鼠皮下,检测各组裸鼠肿瘤体积和重量,Western blot检测肿瘤组织中活化的含半胱氨酸的天冬氨酸蛋白水解酶3(Cleaved Caspase-3)、TPX2、p53水平。结果 siRNA-NC组细胞中TPX2 mRNA和蛋白水平、细胞增殖活性、凋亡率及Cleaved Caspase-3、TPX2、p53水平与Control组比较,差异无统计学意义(P0.05)。siRNA TPX2组细胞中TPX2mRNA和蛋白均明显低于Control组(P0.05)。siRNA TPX2组细胞增殖活性明显降低,凋亡率明显升高,与Control组比较差异有统计学意义(P0.05)。接种siRNA TPX2组细胞的裸鼠肿瘤体积和重量均低于Control组,而肿瘤组织中Cleaved Caspase-3、p53水平均高于Control组,TPX2水平低于Control组(P0.05)。结论下调TPX2抑制肺癌细胞增殖,促进肺癌细胞凋亡,抑制肺癌细胞裸鼠成瘤能力,这可能与促进p53表达和促进Caspase-3活化有关。     

慢病毒介导TIEG1基因乳腺癌靶向载体的构建及活性测定

目的:构建慢病毒介导的TIEG1基因乳腺癌特异性靶向载体,并鉴定其活性。方法:将乳腺癌特异性survivin启动子片段和TIEG1基因先后克隆进带有绿色荧光蛋白的慢病毒载体中,构建survivin启动子驱动的TIEG1基因慢病毒表达载体,酶切及测序鉴定。包装纯化慢病毒颗粒,感染人脐静脉内皮细胞HUVEC和乳腺癌细胞SK-BR-3,观察绿色荧光蛋白的特异性表达。结果:成功构建带有肿瘤特异性survivin启动子驱动的TIEG1基因慢病毒表达载体。感染细胞后,乳腺癌SK-BR-3细胞可观察到绿色荧光表达,而人正常脐静脉内皮细胞基本无表达。半定量RT-PCR证实TIEG1基因在乳腺癌SK-BR-3细胞中过表达。结论:构建的survivin启动子驱动的慢病毒表达载体具有一定的肿瘤特异性,将为实现以慢病毒为载体的TIEG1基因肿瘤靶向治疗提供良好的实验基础。     

siRNA前体慢病毒干扰A549细胞株蛋白激酶2a表达的载体构建及鉴定

目的构建针对蛋白激酶2a（caseinkinase2a,CK2a）基因的siRNA前体（shortharpinRNA,shRNA）表达载体,鉴定CK2a基因干扰效率。方法体外设计并合成针对CK2a基因的慢病毒shRNA干扰载体,通过PCR及测序证实载体构建成功。将人肺腺癌细胞株A549分为3组,病毒干扰组（CK组）将慢病毒颗粒以最适滴度感染细胞株A549,病毒空载组（NC组）将慢病毒颗粒空载体感染细胞株A549,阴性对照组（CON组）为未经任何处理的细胞株A549;检测各组CK2a的干扰效率。结果构建的慢病毒载体序列通过PCR、测序等鉴定证实与设计序列相同;实时定量PCR检测显示CK组A549细胞CK2amRNA表达率较NC组及CON组下降约80％;Westernblotting显示CK组A549细胞表达CK2a蛋白量较NC组及CON组明显减少。结论构建的shRNA表达载体可在mRNA和蛋白水平上有效抑制A549细胞株CK2a基因的表达。     

人核小体结合蛋白1小分子干扰RNA重组慢病毒抑制非激素依赖性前列腺癌体内生长的实验研究

目的探讨重组慢病毒介导的人核小体结合蛋白1（NSBP1）基因沉默对非激素依赖性前列腺癌细胞系DU145移植瘤生长的抑制作用及机制。方法慢病毒lentivirus-NSBP1转染非激素依赖性前列腺癌细胞系DU145。用转染细胞成瘤,观察抑瘤效果。运用实时RT-PCR和Western blot方法检测移植瘤中NSBP1、cyclinB1与Bcl-2的mRNA和蛋白的表达。结果体内实验证实NSBP1表达水平的降低,对肿瘤细胞在裸鼠体内成瘤率没有影响,但对肿瘤的生长有明显抑制作用。同时随着NSBP1表达水平的降低,cyclinB1和Bcl-2的mRNA及蛋白的表达也降低。结论NSBP1-RNAi-lentivirus重组慢病毒能有效抑制DU145细胞移植瘤的生长,NSBP1可能通过调控cyclinB1、Bcl-2基因的变化影响肿瘤细胞的生长。     

Survivin-siRNA对裸鼠视网膜母细胞瘤移植瘤的抑制研究

目的构建Survivin-siRNA真核重组质粒,转染裸鼠视网膜母细胞瘤玻璃体腔移植瘤中,探讨其对肿瘤组织中Survivin表达的抑制作用及诱导凋亡情况。方法构建针对Survivin mRNA特异的靶序列的Survivin-siRNA以及对照Scramble-siRNA。将Y79细胞种植至21只裸鼠玻璃体腔内,9d后随机平均分为mock对照组(注射K-PBS);Scramble对照组(注射带有非同源的Scramble-siRNA重组质粒);Survivin实验组(注射特异性Survivin-siRNA重组质粒)。10d后摘除肿瘤组织,利用半定量RT-PCR检测肿瘤组织Survivin mRNA;采用Western blot方法分析Survivin蛋白;HE染色、Survivin及Ki67免疫组化染色;TUNEL法检测肿瘤组织凋亡。结果真核重组质粒及视网膜母细胞瘤裸鼠玻璃体腔移植瘤模型均构建成功。半定量RT-PCR显示Survivin-siRNA在mRNA水平上抑制了Survivin基因转录(P0.01),Scramble组与mock组无差别(P0.05)。Western blot显示与mock组和Scramble组相比,实验组细胞的Survivin蛋白表达显著降低(P0.01)。HE染色普通光镜下观察,实验组与两对照组相比,在瘤组织内可见到较多死亡细胞;实验组移植瘤组织中Survivin蛋白表达与mock组和scramble组相比明显下降;实验组Ki67的表达较对照组下降明显,增殖指数明显下降(P0.01)。TUNEL法显示实验组肿瘤组织内可见大量细胞核染为棕黄色的凋亡细胞,对照组可见少许凋亡细胞,实验组凋亡指数明显高于对照组(P0.01)。结论成功构建的Survivin-siRNA重组质粒可以抑制裸鼠视网膜母细胞瘤移植瘤中Survivin基因转录和蛋白表达,诱导了肿瘤细胞凋亡。     

STAT3反义寡核苷酸对肺腺癌裸鼠移植瘤辐射增敏的研究

目的：探讨STAT3反义寡核苷酸（antisense oligodeoxynucleotide,ASODN）对肺腺癌裸鼠移植瘤辐射增敏的影响,为提高恶性肿瘤的辐射敏感性提供新的思路和方法。方法建立裸鼠体内肺腺癌移植瘤动物模型,待瘤体直径＞0.5 cm后,瘤内多点注射STAT3 ASODN,给药剂量：15 mg/kg,1次/d,连续2周,给药后2 h联合γ射线局部照射总剂量20 Gy,每次2 Gy,每周5次,连续2周,照射剂量率0.75 Gy/min,定期测量肿瘤体积,绘制肿瘤生长曲线;测量肿瘤质量,计算抑瘤率;记录存活情况,估算生存率,绘制生存曲线,计算总生存期;免疫组化检测肿瘤组织细胞内STAT3蛋白表达变化情况;Western Blot 检测肿瘤组织内 P-STAT3、Bcl-xL、CyclinD1蛋白表达情况。结果反义（antisense,AS）＋照射（irradiation,IR）组肿瘤体积治疗第8天开始明显小于其余各组肿瘤体积（P＜0.05）;AS＋IR组的抑瘤率为68.4%,高于IR组与AS组的之和;AS＋IR组的平均总生存期为（28.38±0.96）d,明显高于IR组及无义（nonsense,NS）＋IR组（P＜0.005）;STAT3蛋白及其下游Bcl-xL、CyclinD1蛋白表达变化明显下降, STAT3蛋白磷酸化水平也降低。结论 STAT3反义寡核酸能够增强肺腺癌裸鼠移植瘤的辐射敏感性,具有良好的放疗增敏剂临床应用开发前景。     

Restoration of p53 tumor-suppressor activity in human tumor cells in vitro and in their xenografts in vivo by recombinant avian adenovirus CELO-p53

Human adenovirus (Ad) vectors are extensively used as gene transfer vehicles. However, a serious obstacle for the use of these vectors in clinical applications is due to pre-existing immunity to human Ads affecting the efficacy of gene transfer. One of the approaches to circumvent host immune response could be the development of vectors based on non-human Ads that are able to transduce genes into human cells. In this study, we explored the possibility of using avian Ad CELO vectors as gene-transfer vehicles. For this purpose, we constructed a set of recombinant CELO viruses and demonstrated that they are able to deliver transgenes into various organs on the background of pre-existing immunity to human Ad5. The created CELO-p53 vector restored the function of the p53 tumor suppressor both in cultured human tumor cells in vitro and in their xenografts in nude mice in vivo. The latter effect was accompanied by inhibition of tumor growth. Noteworthily, the delivery of CELO-p53 led to activation of p53 target genes in cells showing inactivation of endogenous p53 by three different mechanisms, that is, in the human epidermoid carcinoma A431, lung adenocarcinoma H1299, and cervical carcinoma HeLa.     

靶向血管内皮生长因子siRNA对K562细胞凋亡及survivin表达的影响

目的 应用腺病毒介导的血管内皮生长因子(VEGF) siRNA沉默K562细胞中VEGF的表达,观察其对K562细胞凋亡及凋亡抑制基因survivin表达的影响.方法 应用成功构建的携带特异性VEGF siRNA的重组腺病毒(Ad5-VEGF siRNA)感染K562细胞,实验分为3组:实验组(K562/Ad5-VEGF siRNA组)、空载体组(K562/Ad5组)、对照组(K562组).通过RT-PCR法检测细胞内VEGF及survivin mRNA的表达,ELISA法检测细胞培养上清中VEGF蛋白表达,Western blot法检测细胞survivin蛋白表达,流式细胞术检测细胞凋亡.结果 实验组细胞VEGF及survivin mRNA表达水平较对照组均有明显降低(P＜0.01),且细胞培养上清中VEGF蛋白表达水平[(1121±15)pg/ml]低于空载体组[(1290±28)pg/ml]和对照组[(1303±28)pg/ml](P＜0.01).Western blot法检测结果显示,实验组survivin蛋白表达水平(0.26 ± 0.11)较对照组(0.74±0.10)也显著降低(P＜0.01).实验组细胞凋亡率与对照组比较明显增加(P＜0.01).结论 应用RNA干扰沉默K562细胞中VEGF基因表达后,survivin的表达也随之降低,同时细胞凋亡率相应增加.VEGF可诱导K562细胞中survivin基因表达,可能是survivin基因表达的上游调控因子.     

Stable transgene expression in tumors and metastases after transduction with lentiviral vectors based on human immunodeficiency virus type 1

The relatively low efficiency of target cell transduction and variations in the stability of transgene expression by retroviral vectors based on the Moloney murine leukemia virus (MoMLV) are major impediments to the use of such vectors in cancer gene therapy approaches. The present study was designed to investigate the stability and efficiency of transgene expression in human lung and breast cancer cell lines transduced with vectors based on human immunodeficiency virus type 1 (HIV-1) in vitro and in vivo in nude mouse models of metastasis. H460 lung carcinoma cells and MDA-MB-231 breast carcinoma cells were transduced with lentiviral vectors encoding enhanced green fluorescent protein (EGFP) and beta-galactosidase (beta-Gal), respectively. Transduced H460 cells were administered to nude mice by either intravenous or subcutaneous injection and MDA-MB-231 cells were implanted orthotopically into the mammary fat pad of such mice to induce primary tumor and metastatic lung tumor formation. High-level EGFP expression was maintained in transduced H460 cells in metastatic lung nodules for up to 6 weeks and transgene expression in vitro persisted for at least 23 days after retrieval of EGFP-positive H460 cells from the lungs of tumor-bearing mice and subsequent cultivation in vitro. Likewise, beta-Gal expression levels in metastatic MDA-MB-231 cells in lungs remained high for up to 11 weeks. Southern blot analyses carried out with DNA from lung nodules showed that proviral DNAs in H460 cells were maintained stably over many cell generations and during subsequent reimplantation in vivo. However, molecular analyses revealed variations in transgene copy numbers and expression levels among individual lung clones. These results demonstrate the usefulness of HIV-1-based lentiviral vectors for sustained and stable transgene expression in human lung and breast cancer cell lines in vitro and in vivo.     

Expression of epidermal growth factor (EGF)/transforming growth factor-alpha by human lung cancer cells determines their response to EGF receptor tyrosine kinase inhibition in the lungs of mice

Epidermal growth factor receptor (EGFR) has been extensively targeted in the treatment of non-small cell lung cancer, producing responses in a small number of patients. To study the role of ligand expression in mediating response to EGFR antagonism, we injected NCI-H441 [EGFR and EGF/transforming growth factor-alpha (TGF-alpha) positive] or PC14-PE6 (EGFR positive and EGF/TGF-alpha negative) human lung adenocarcinoma cells into the lungs of nude mice. We randomized the mice to receive treatment with the EGFR tyrosine kinase inhibitors gefitinib or AEE788 or vehicle. Treatment of mice bearing NCI-H441 but not PC14-PE6 lung tumors resulted in a significant reduction in primary tumor growth, pleural effusion, and lymph node metastasis. Immunohistochemical analyses revealed that NCI-H441 and PC14-PE6 cells expressed EGFR but that the expression of EGF/TGF-alpha was high in NCI-H441 cells and very low in PC14-PE6 cells. Consequently, EGFR was activated in both tumor and tumor-associated endothelial cells in the NCI-H441 tumors but not in the PC14-PE6 tumors. Antagonism of EGFR signaling by treatment of mice with AEE788 decreased proliferation and increased apoptosis of both tumor cells and tumor-associated endothelial cells in NCI-H441 tumors but not in PC14-PE6 tumors. However, after transfection of PC14-PE6 cells with TGF-alpha, lung tumors derived from the transfected cells expressed and activated EGFR in both tumor and tumor-associated endothelial cells and tumors responded to treatment with AEE788. Collectively, these results strongly suggest that the response of human lung cancers growing orthotopically in mice to the inhibition of EGFR signaling is determined by ligand (EGF/TGF-alpha) expression by tumor cells. Our findings provide an additional explanation for the susceptibility of lung cancers to treatment with EGFR tyrosine kinase inhibitors.