RhoA、RhoC串联RNA干扰载体的构建及在结直肠癌细胞中的表达

目的 探讨RhoA、RhoC串联RNA干扰载体的构建及在结直肠癌细胞中的表达.方法 设计合成4对靶向RhoA与RhoC基因的各两对寡核苷酸序列,退火后分别克隆入shRNA表达载体;通过一系列的酶切与连接,将该4段干扰片段串联起来,构建一个同时表达4个shRNA的重组质粒.经酶切和测序鉴定重组质粒.脂质体法转染HCT116,荧光定量聚合酶链反应(FQ-PCR)检测各细胞中RhoA、RhoC mRNA的表达,噻唑蓝(MTT)比色法检测细胞的增殖活性.结果　经酶切和测序证实重组质粒pGenesil2.7-A1+A2+C1+C2构建成功.转染该重组质粒后细胞中RhoA、RhoC mRNA的表达水平分别为(0.78±0.11)和(0.90±0.21),明显低于空白对照组(0±0.15、0±0.09)和阴性对照组(-0.05±0.12、0.11±0.10,P＜0.05),且细胞的生长增殖率(63.8±12.5)%也显著低于对照组和质粒对照组(101.6±13.7)%(P＜0.05).结论　成功构建4个shRNA串联的重组表达载体,该载体可在体外高效表达.

Abstract：

Objective To construct and identify recombinant RhoA and RhoC shRNAs Tandem expression vector pGenesil2. 7-A1 + A2 + C1 + C2 and observe its expression in human colorectal carcinoma cells HCT116. Methods Four pairs of hairpin-like oligonucleotide sequences special for human RhoA or RhoC gene were designed and synthesized. The annealed oligonucleotide fragments were subcloned into four plasmids each with a different promotor. Then the four oligonucleotide fragments were series connected to construct an efficient multiple shRNAs expression system. The tandem array multiple shRNAs expression vector was confirmed by enzyme digestion and DNA sequencing and then was transfected into HCT 116 usingLipofectamneTM 2000. The expression of RhoA or RhoC mRNA was detected by fluorescence quantitative polymerase chain reaction (FQ-PCR). Cellular proliferation inhibitory activity was determined by methyl thiazolyl tetrazolium (MTT) assay. Results Enzyme digestion and DNA sequencing showed that the oligonucleotide fragments were correctly inserted into pGenesil2. 7-A1 + A2 + C1 + C2 plasmid. After transfection, the expression of RhoA or RhoC mRNA was (0.78 ±0. 11)or (0.90 ±0.21) ,significantly lower than that in control group (0 ±0. 15、0 ±0. 09) and plasmid control group ( -0. 05 ±0. 12、0. 11 ±0. 10)(P＜0. 05) ,and the proliferation rate (63. 8 ± 12. 5)% was also lower as compared with control group and plasmid control group ( 101.6 ± 13.7 ) % ( P ＜ 0. 05 ). Conclusion The recombinant tandem array multiple shRNAs expressing vectors can effectively silence the expression of RhoA or RhoC in human colorectal carcinoma cells.     

大鼠STAT3特异性shRNA慢病毒载体的构建与鉴定

目的在已经成功构建4个针对STAT3的shRNA质粒表达载体的基础上,筛选出干扰效果最佳者进行慢病毒包装并鉴定。方法将STAT3的干扰质粒shRNA1、shRNA2、shRNA3、shRNA4及Control1(空载体对照),Control2(无效shRNA对照)分别转染目的细胞(大鼠肾小球系膜细胞),48h后收集细胞提取mRNA,以RT-PCR检测各组分STAT3表达量。对于筛选所得干扰效果最佳的质粒,采用pPACKH1TM慢病毒载体系统进行病毒包装。利用绿色荧光蛋白作为报告基因,对感染效率及病毒滴度进行检测。结果 RT-PCR检测结果显示,shRNA3样品受干扰的效果最佳。成功构建了慢病毒载体Lenti-shRNA3,共转染293T细胞24h、48h,荧光显微镜下可见强绿色荧光,细胞生长状态良好,表明病毒包装成功。转染HT1080细胞,收集慢病毒液,测定病毒滴度为3.34×108ifu/ml,适合感染目的细胞。结论成功构建了STAT3基因的shRNA慢病毒表达载体,为进一步应用奠定了基础。     

靶向S100A4的shRNA对乳腺癌MCF-7细胞体外侵袭力及迁移力的影响

目的探讨靶向S100A4短发夹RNA（shRNA）对MCF-7细胞侵袭力和迁移力影响的作用机制。方法构建S100A4基因特异性shRNA表达载体,使用QRT-PCR和Westernblot检测转染后MCF-7细胞中s100A4的表达水平,经过脂质体介导将S100A4-shRNA表达载体转染人MCF-7细胞,G418筛选及克隆化培养。采用Trans-well小室法和划痕试验检测MCF-7细胞侵袭力和迁移力变化。结果经测序鉴定证实S100A4-shRNA表达载体成功构建。转染48h后,所构建的S100A4-shRNA-1表达载体能有效抑制MCF-7细胞中S100A4表达;MCF-7细胞形态无显著变化,但侵袭力和迁移力明显下降。结论S100A4在乳腺癌细胞侵袭和转移过程中扮演重要角色,通过沉默其表达可抑制MCF-7的侵袭力和迁移力从而抑制其转移。     

Identification and functional analysis of genes which confer resistance to cisplatin in tumor cells

The efficacy of cisplatin during cancer chemotherapy is often impaired by the emergence of cancer cells which become resistant to chemotherapeutic agents. While various mechanisms have been proposed to explain resistance to cisplatin, the genes involved in this process still remain unclear. By using DNA microarrays, we performed a genome-wide analysis of cisplatin-resistant HeLa cells in order to identify genes involved in resistance. We identified nine genes (NAPA, CITED2, CABIN1, ADM, HIST1H1A, EHD1, MARK2, PTPN21, and MVD), which were consistently upregulated in two cisplatin-resistant HeLa cell lines. The upregulated genes, here referred to as cisplatin resistance genes (CPR), were further analyzed for their ability to modify the response of HEK293 cells to cisplatin. Short-hairpin RNA (shRNA) knockdown of CPR genes, individually or in combination, was shown to sensitize HEK293 cells to cisplatin, but not to vincristine or taxol, suggesting that CPR genes may be involved specifically in cisplatin resistance. Among the treatments performed, shRNA knockdown of NAPA was the most efficient treatment able to sensitize cells to cisplatin. Furthermore, shRNA knockdown of a single CPR gene was sufficient to partially reverse acquired cisplatin resistance in HeLa cells. Sensitization to cisplatin following knockdown of CPR genes was also observed in the tumorigenic cell lines Sk-ov-3, H1155, and CG-1. Based on these results, we propose that the CPR genes identified here may represent potential candidates for novel target therapies aimed at preventing resistance to cisplatin during chemotherapy.     

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。