双启动子shRNA真核表达载体的构建

目的:构建含有双启动子的shRNA真核表达载体.方法:通过PCR分别扩增带有BamH Ⅰ、EcoR Ⅰ酶切位点的人U6启动子序列(U6-B/E)和带有Bgl Ⅱ、HindⅢ酶切位点的人U6启动子序列(U6-B/H),用BamH Ⅰ与EcoRⅠ双酶切pcDNA3.1(+)与PCR产物U6-B/E后进行连接,重组质粒命名为psPRO.再用BglⅡ与HindⅢ双酶切psPRO与PCR产物U6-B/H后进行连接,构建含有双启动子的shRNA真核表达载体.结果:酶切鉴定以及DNA测序结果显示载体构建成功.结论:构建双启动子的shRNA真核表达载体,使其在细胞中表达2个不同的siRNA,不仅筛选方便,而且可以通过建立这种模式化工具载体,为今后RNA干扰实验研究的开展和深入提供手段.     

21.5kD MBP RNAi有效靶点的筛选及验证

目的:构建21.5 kD MBP基因干扰序列21.5 kD MBP-shRNA(21.5 kD MBP short hairpin RNA interference),筛选最佳沉默效果的21.5 kD MBP-shRNA真核表达载体,为21.5 kD MBP基因功能研究提供实验材料。方法:将21.5 kD MBP-shRNA阳性真核表达载体和阴性真核表达载体经脂质体介导分别转入人神经胶质瘤细胞株U251中,观察转染24 h后的转染效率;提取各组细胞总RNA,用实时荧光定量PCR技术检测各组21.5 kD MBP基因在mRNA水平的表达差异性。结果:21.5kD MBP-shRNA真核表达重组载体被成功转染入U251细胞,与阴性对照质粒(pGenesil-1-MBP-neg)转染组相比,沉默质粒转染组(pGenesil-1-MBP-1、pGenesil-1-MBP-2、pGenesil-1-MBP-3质粒分别转染)细胞中21.5 kD MBP mRNA表过水平均显著下降(P<0.05),其中pGenesil-1-MBP-3转染组细胞中21.5 kD MBP mRNA表达水平最低。结论:成功筛选出最佳沉默效果的21.5 kD MBP-shRNA真核表达载体,为21.5 kD MBP基因功能研究及基因治疗研究奠定了实验基础。     

miR-374过表达增强人乳腺癌细胞对多西他赛的耐药性

目的:观察miR-374过表达对人乳腺癌MDA-MB-231细胞docetaxel(多西他赛)耐药性的影响。方法:qPCR检测miR-374过表达细胞MDA-MB-231-miR-374和对照细胞MDA-MB-231-Cherry中miR-374的相对含量;采用不同浓度的多西他赛处理细胞72小时后,MTT检测细胞的活性。在终浓度为3.2nmol/L的多西他赛处理下,用平板克隆实验检测MDA-MB-231-Cherry和MDA-MB-231-miR-374细胞的增殖能力。流式细胞术检测细胞周期和凋亡。结果:与MDA-MB-231-Cherry细胞相比,miR-374过表达细胞MDA-MB-231-miR-374中miR-374的相对表达量明显增高;MDA-MB-231-miR-374细胞的耐药性和克隆形成能力明显增强(P<0.05)。细胞凋亡率明显降低,G0/G1期细胞减少,S期细胞增加,G2/M期细胞增加。结论:miR-374过表达可明显增强乳腺癌细胞株MDA-MB-231对多西他赛的耐药性。     

Targeted silencing of heparanase gene by small interfering RNA inhibits invasiveness and metastasis of osteosarcoma cells

The effects of targeted silencing of heparanase gene by small interfering RNA(siRNA) on invasiveness and metastasis of osteosarcoma cells(MG63 cells) were investigated in the present study.Two complementary oligonucleotide strands were synthesized and inserted into pGenesil-1 vector based on the mRNA sequence of heparanase gene.The expression vector containing short hairpin RNA(pGenesil-shRNA) was constructed successfully.MG63 cells were randomly allocated into 3 groups:blank group,empty vector(pGenesil) transfected group and expression vector(pGenesil-shRNA) transfected group.Under the induction of Lipofectamine 2000,the recombinants were transfected into MG63 cells.Heparanase gene expression level was detected by RT-PCR and Western blotting.Cell prolifera-tion was measured by MTT assay.Cell invasiveness and metastasis were examined by cell adhesion and Transwell-ECM assays.HUVECs migration assay was applied for the detection of angiogenesis.As compared with negative controls,the mRNA and protein expression levels of heparanase were down-regulated by 76.1%(P<0.01) and 75.3%(P<0.01) respectively in the pGenesil-shRNA transfected group.Meanwhile,the proliferation,adhesiveness,invasiveness and angiogenesis properties of MG63 cells were all significantly inhibited.It was suggested that targeted silencing of heparanase gene by siRNA could dramatically inhibit the invasiveness and metastasis of osteosarcoma cells.     

Neocortical disruption and behavioral impairments in rats following in utero RNAi of candidate dyslexia risk gene Kiaa0319

Within the last decade several genes have been identified as candidate risk genes for developmental dyslexia. Recent research using animal models and embryonic RNA interference (RNAi) has shown that a subset of the candidate dyslexia risk genes--DYX1C1, ROBO1, DCDC2, KIAA0319--regulate critical parameters of neocortical development, such as neuronal migration. For example, embryonic disruption of the rodent homolog of DYX1C1 disrupts neuronal migration and produces deficits in rapid auditory processing (RAP) and working memory--phenotypes that have been reported to be associated with developmental dyslexia. In the current study we used a modified prepulse inhibition paradigm to assess acoustic discrimination abilities of male Wistar rats following in utero RNA interference targeting Kiaa0319. We also assessed spatial learning and working memory using a Morris water maze (MWM) and a radial arm water maze. We found that embryonic interference with this gene resulted in disrupted migration of neocortical neurons leading to formation of heterotopia in white matter, and to formation of hippocampal dysplasia in a subset of animals. These animals displayed deficits in processing complex acoustic stimuli, and those with hippocampal malformations exhibited impaired spatial learning abilities. No significant impairment in working memory was detected in the Kiaa0319 RNAi treated animals. Taken together, these results suggest that Kiaa0319 plays a role in neuronal migration during embryonic development, and that early interference with this gene results in an array of behavioral deficits including impairments in rapid auditory processing and simple spatial learning.     

慢病毒载体介导shRNA的研究进展

RNA干扰（RNAi）通过双链RNA的介导,特异性阻止相关序列的表达,从而导致转录后水平的基因沉默.RNAi广泛存在于真核生物中.慢病毒载体是理想的真核细胞基因转移工具,广泛应用于相关的RNAi研究领域,如抗病毒研究、癌症及其治疗、基因治疗.现已发现,慢病毒载体能够介导组织、时间特异的RNAi,在疾病的基因靶向治疗上必有广阔前景.     

C-erbB-2 shRNA对小鼠肺腺癌细胞化疗敏感性的影响及其机制

目的：探讨人表皮生长因子受体2短发夹RNA(C-erbB-2 shRNA)对小鼠肺腺癌Lewis细胞化疗敏感性的影响及其机制，为非小细胞肺癌尤其是腺癌的治疗提供新的思路。方法：常规培养小鼠肺腺癌Lewis细胞，分为未转染组、pGPU6/RFP/Neo-shNC组和pGPU6/RFP/Neo-erbB-2组；应用Lipofectamine 2000将质粒快速转染各组Lewis细胞；应用RT-PCR法检测各组细胞C-erbB-2 mRNA表达水平；应用Western blottting法检测各组细胞C-erbB-2蛋白表达水平。将Lewis细胞分为未转染对照组、pGPU6/RFP/Neo-shNC组、卡铂组、pGPU6/RFP/Neo-erbB-2组、pGPU6/RFP/Neo-erbB-2+卡铂组和pGPU6/RFP/Neo-shNC + 卡铂组；应用流式细胞术检测各组细胞凋亡率；应用Western blotting法检测各组细胞Bcl-2和Bax蛋白表达水平。结果：pGPU6/RFP/Neo-erbB-2组C-erbB-2 mRNA和蛋白表达水平均低于未转染组和pGPU6/RFP/Neo-shNC组；pGPU6/RFP/Neo-erbB-2+卡铂组细胞凋亡率高于其他各组（P<0.01）；与其他各组比较，pGPU6/RFP/Neo-erbB-2 + 卡铂组Bcl-2蛋白表达水平下降、Bax蛋白表达水平增加。结论：C-erbB-2 shRNA能增强小鼠肺腺癌Lewis细胞对卡铂的敏感性，其机制可能是通过上调Bax蛋白、下调Bcl-2蛋白表达，进而增强卡铂诱导的细胞凋亡。     

食管鳞癌ECA109细胞中Survivin通过ERK信号通路调控c-myc基因表达的机制

目的：探讨在食管鳞癌ECA109细胞中Survivin对c-myc基因的调控作用。方法：将食管鳞癌ECA109细胞分为Survivin shRNA干扰组、阴性质粒对照组（Control shRNA）和空白细胞株（未加任何处理的食管癌ECA109细胞）,将2μg Survivin shRNA质粒、2μg Control shRNA质粒分别转染ECA109细胞,48 h后收集各组细胞,采用RT-PCR法检测各组Survivin、c-myc mRNA的表达,Western blot法检测Survivin、c-myc蛋白及p-ERK蛋白的表达;采用ERK、p38、JNK、JAK/STA3、PI3K/Akt信号传导通路的特异性抑制剂分别阻断ECA109细胞中关键激酶的表达,RT-PCR法检测c-myc mRNA的表达。结果：与阴性质粒对照组和空白细胞组比较,Survivin shRNA组Survivin表达下调,c-myc mRNA及蛋白的表达降低,差异均具有统计学意义（P均 < 0.05）;采用ERK、p38、JNK、JAK/STA3、PI3K/Akt信号通路抑制剂分别作用于食管癌ECA109细胞,PD98059（ERK信号通路阻断剂）组c-myc mRNA及蛋白表达降低（P < 0.05）;Survivin shRNA干扰沉默Survivin基因后ERK磷酸化蛋白表达降低（P < 0.05）。结论：Survivin对c-myc具有正向调控作用,可能通过ERK信号传导通路调控c-myc的表达。