Enhanced Chemotherapy Sensitivity of Human Colon Cancer Cells to 5-Fluorouracil by siRNA Recombinant Expression Vector Targeting Survivin Gene

Objective To investigate the effects of small interfering RNA （siRNA） recombinant expression vector targeting survivin gene on chemotherapy sensitivity of human colon cancer cells to 5-fluorouracil. Methods siRNA recombinant expression vector targeting survivin gene was constructed and transfected into human colon cancer cell lines LOVO. After 48 hours of transfection, cells were harvested for analysis of survivin mRNA and protein expressions using RT-PCR and Western blot. In addition, after human colon cancer cell lines were treated with Survivin siRNA and/or 5-fluorouracil, MTT assay and flow cytometry were used to analyze cell proliferation and apoptosis. Results Restriction endonuclease analysis confirmed that siRNA recombinant expression vector targeting survivin gene was successfully constructed. Inhibitory ratios of survivin mRNA and protein expressions by Survivin siRNA were 36.33% and 44.65%, respectively. Survivin siRNA combined with 5-fluorouracil significantly increased the cell proliferation inhibitory ratio and apoptosis ratio compared with 5-fluorouracil treatin~ alone （P〈0.05）. Conclusion The siRNA recombinant expression vector targeting survivin gene can inhibit the expression of survivin gene, and enhance chemotherapy sensitivity of human colon cancer cells to 5- fluorouracil.     

Effect of siRNA Targeting Survivin Gene on the Biological Behavior of Hepatocellular Carcinoma

To study the influence of siRNA targeting survivin gene on the biological behavior of hepatocellular carcinoma (HCC), one pair of 21bp reverse repeated motifs of survivin target sequence with 9 spacers were synthesized and inserted into plasmid psilencer2.1 to generate siRNA eukaryotic expression vector. After stable transfection into HepG2 cells, the biological behaviors of the survivin siRNA transfected HCC cells were observed. After the recombinant plasmid Psilence( )-survivin was successfully constructed, survivin mRNA and protein expression inhibition ratio reached 73% and 75% respectively compared to control groups. Transfected cells with survivin siRNA demonstrated significantly inhibited cell growth and increased apoptosis. Subsequent study in nude mouse model demonstrated lower succeeding rate in cells transfected with survivin siRNA and slow growth rate. The results elucidated the siRNA targeting survivin gene could specially suppress its expression in HepG2 cells and inhibit tumor cells growth both in vivo and in vitro. This provides a theoretical basis to turn the drug resistance in tumor cells.     

Impact of silencing MMP9 gene on the biological behaviors of trophoblasts

This study examined the effect of MMP9 gene on the biological behaviors of trophoblasts and explore the relation between MMP9 gene and the "superficial implantation of placenta". In vitro cultured trophoblasts (TEV-1 cells) were transfected with synthesized double-stranded MMP9 RNA (siRNA) by using lipofectamine2000TM technique and the expressions of MMP9 mRNA and protein and the growth and invasiveness of the TEV-1 cells were determined. Our results showed that siRNA transfection could significantly inhibit the expression of MMP9 gene in the TEV-1 cells and the growth and invasiveness of the TEV-1 cells transfected RNA was significantly reduced (P<0.01). We are led to conclude that silencing of MMP9 gene with siRNA can inhibit the growth and invasiveness of trophoblasts and increasing the expression of MMP9 might help prevent and treat preeclampsia.     

Inhibition of cell proliferation by siRNA targeting hPRLR in breast cancer MCF-7 cell line

Objective： To study the inhibition of proliferation of breast cancer by small interfering RNA（siRNA） targeting human prolactin （hPRLR） and the underlying mechanisms. Methods：The siRNA targeting hPRLR was chemically synthesized and transfected into MCF-7 cells, the expression of hPRLR was analyzed by real-time quantitive PCR, cell growth inhibition was measured with MTT assay, cell cycle of the transfected cells was examined by flow cytometry, meanwhile, expression of cyclin D1 was tested by semi-quantitative RT-PCR, Results：24 h after transfection with 100 nmol/L siRNA-PRLR, the expression of hPRLR mRNA was suppressed by 65%, cells in G1 phase increased, but cells in S phase decreased. Down regulated hPRLR expression exhibited significant inhibition in cell proliferation. And the expression of cyclin D 1 was down regulated. Conclusion：The results indicate that siRNA-hPRLR is a useful tool for silencing hPRLR expression and inhibiting cell proliferation in breast cancer MCF-7 cell line, and it may be a possible new approach for breast cancer gene therapy.     

RNAi knockdown of C-erbB2 expression inhibits salivary gland adenoid cystic carcinoma SACC-83 cell growth in vitro

Objective：To knockdown the C-erbB2 gene in salivary gland adenoid cystic carcinoma SACC-83 cells using RNA interference,and determine the effect of silencing C-erbB2 on cell proliferation.Methods：C-erbB2-siRNA was transfected into SACC-83 cells.RT-PCR and immunohistochemistry were used to detect C-erbB2 expression in SACC-83 cells.Cell proliferation was measured by the MTT assay and gene knockdown was achieved by RNA interference.Apoptosis was analyzed by flow cytometry.Results：Compared with the control,C-erbB2 mRNA expression was decreased in the C-erbB2-siRNA transfection group,and immunohistochemical analysis indicated that C-erbB2 protein expression was decreased.After C-erbB2-siRNA was transfected for 48 h,absorbance at 570 nm （MTT）was 0.185±0.021 compared with 0.354±0.034,0.299±0.053,and 0.314±0.049 in the blank control,liposome control and negative control siRNA groups,respectively.The differences were statistically significant （P〈0.05）between the C-erbB2-siRNA group and the control groups.Following the C-erbB2 knockdown,the percentage of apoptotic cells was 5.63%compared with 2.04%,2.85%,and 2.98%in the three control groups,respectively.Proliferation of SACC-83 cells was inhibited,and early apoptotic cells were increased.Conclusion： RNA interference can effectively silence C-erbB2 gene expression and inhibit growth of SACC-83 cells,which indicates the potential of targeting this gene as a novel gene therapy approach for the treatment of salivary gland adenoid cystic carcinoma.     

Effects of Mitofusin-2 Gene on Cell Proliferation and Chemotherapy Sensitivity of MCF-7

In order to evaluate the effect of mitofusin-2 gene （mfn2） on proliferation and chemotherapy sensitivity of human breast carcinoma cell line MCF-7 in vitro, pEGFPmfn2 plasmid carrying full length of mitofusin-2 gene was transfected, by using sofast, into MCF-7 cells. Mitofusin-2 gene expression in MCF-7 cells transfected by sofast after 48 h was detected by PCR and Western blotting, and the stable expression of GFP protein in MCF-7 cells by Western blot analysis. The proliferation of MCF-7 cells was assayed by MTT and cell counting. By using PI method, the effects of mfn2 on the cell cycle distribution of MCF-7 were measured. Annexin-Ⅴ/PI double labeling method was employed to detect the changes in apoptosis induced by chemotherapeutics before and after transfection. The results showed that the MCF-7 cells transfected with mfn2 gene could stably and highly express GFP protein. MTT assay revealed that after transfection of mfn2 cDNA, the proliferation of MCF-7 cells was significantly inhibited. DNA histogram showed that cells arrested in S phase, and the percentage of S phase cells was 42.7, 17.2 and 19.6 in mfn2 cDNA transfection group, blank plasmid transfection group and blank control group, respectively （P〈0.05）. The apoptosis ratio of the cells transfected with mfn2 gene was increased from 3.56% to 15.95%, that of the cells treated with camptothecin （CAMP） followed by mfn2 gene transfection was 69.6%, and that in blank plasmid transfection group and blank control group was 31.0% and 23.4% respectively （P〈0.05）. It was suggested that transfection of mfn2 gene could significantly inhibit the proliferation of MCF-7 cells and promote their sensitivity to CAMP with a synergic effect.     

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.     

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.     

Effect of Antisense RNA Targeting Polo-like Kinase 1 on Cell Growth in A549 Lung Cancer Cells

In order to investigate the effect of Polo-like kinase-1 （Plk1） depletion on cell cycle progression and cell growth in lung cancer cells, a recombinant plasmid containing antisense RNA targeting Plk1 （pcDNA3-Plk1） was transfected into A549 cells by lipofectine. RT-PCR and Western-blot were used to detect the Plk1 gene expression. Cell proliferation was evaluated by direct cell counting and bromodeoxyuridine （BrdU） labeling. Cell cycle distribution and apoptosis were examined by flow cytometry, and the inhibition rate （IR） by vinorebline （NVB） was determined by MTF assay. The results showed that after transfection of pcDNA3-Plk1 into A549 cells, the expression levels of Plk1 mRNA and protein were greatly decreased. In pcDNA3-Plk1 transfected groups, abnormal morphological changes of cells and growth inhibition were observed, and the BrdU labeling index was significantly lower than in the control groups （P〈0.05）. Cells in pcDNA3-Plk1 transfected groups were arresed in G2/M phase and apoptosis was detectable 72 h post transfection. IR induced by vinorebline in pcDNA3-Plk1 transfected groups was significantly higher than in other groups. These data suggested that antisense RNA targeting Plk1 could suppress the Plk1 expression, and therefore, significantly inhibit cell proliferation and induce cell cycle arrest and apoptosis. Moreover, it sensitized lung cancer cells to chemotherapy.     

siRNA干预CTGF和TIMP-1对大鼠肝星状细胞胶原分泌的影响

目的研究小干扰RNA(small interfering RNA,siRNA)沉默结缔组织生长因子(connective tissue growthfactor,CTGF)和组织金属蛋白酶抑制剂-1(tissue inhibitor of matrix metalloproteinases,TIMP-1)对肝星状细胞(hepaticstellate cell,HSC)CTGF和TIMP-1基因表达以及对Ⅰ、Ⅲ型胶原分泌的影响。方法根据已筛选出的对CTGF和TIMP-1基因最有效的RNA干扰靶位,将化学合成siRNA CTGF和siRNA TIMP-1以脂质体LipofectamineTM2000介导,瞬时转染HSC-T6细胞,分别设siRNA CTGF组、siRNA TIMP-1组、siRNA CTGF和siRNA TIMP-1联合组、脂质体组及非特异性(negative control,NC)siRNA组,抽提转染24、48h细胞mRNA和蛋白,并收集细胞上清液。应用RT-PCR鉴定CTGF和TIMP-1mRNA的表达;Western blot检测其蛋白表达;ELISA法检测Ⅰ、Ⅲ型胶原的分泌。结果各干预组转染24、48h后分别与脂质体组和NC siRNA组比较,HSC-T6细胞CTGF及TIMP-1mRNA和蛋白表达均明显下调(均P<0.05),且干预组HSC-T6培养上清液中Ⅰ、Ⅲ型胶原含量明显减少(均P<0.05)。siRNA联合组分别与siRNA CTGF组和siRNA TIMP-1组比较,于转染48hsiRNA联合组较siRNA TIMP-1组抑制率高,细胞上清液中Ⅰ、Ⅲ型胶原量比siRNA TIMP-1组少,且差异具有统计学意义(均P<0.05);而与siRNA CTGF组比较,其CTGF mR-NA和蛋白抑制率增高,细胞上清液中Ⅰ、Ⅲ型胶原量较siRNA联合组减少,但差异无统计学意义(均P>0.05)。结论针对HSC-T6CTGF mRNA基因全长943位点和TIMP-1mRNA 304位点化学合成的siRNA,对靶基因mRNA和蛋白表达有较好的抑制效果,CTGF和TIMP-1沉默可显著减少细胞上清液中Ⅰ、Ⅲ型胶原含量;CTGF和TIMP-1两种基因同时沉默,有增强抗肝纤维化效果的可能。     

Gli1小分子干扰RNA对人胰腺癌细胞增殖和凋亡的影响

目的:研究锌指转录因子Gli1小分子干扰RNA(siRNA)对人胰腺癌PC-2细胞的增殖和凋亡的影响。方法:筛选出最佳的靶向Gli1siRNA转染人胰腺癌PC-2细胞,采用逆转录-聚合酶链反应(RT-PCR)和Western印迹分别从mRNA和蛋白水平检测抑制效果,四甲基偶氮唑蓝(MTT)和TUNEL+PI双染流式细胞检测Gli1被抑制后细胞增殖和细胞凋亡的情况。结果:Gli1siRNA能在mRNA和蛋白水平下调人胰腺癌细胞株PC-2中Gli1基因的表达,以转染72h时最显著。Gli1表达被抑制后,转染后72h时PC-2细胞生长受到明显抑制,凋亡细胞显著增多。结论:Gli1与胰腺癌细胞的生长和凋亡密切相关,抑制胰腺癌细胞中Gli1表达可抑制胰腺癌细胞生长,促进胰腺癌细胞凋亡。     

siRNA沉默c－myc对肾上腺皮质癌SW－13细胞增殖的影响

目的：应用siRNA干扰肾上腺皮质癌SW－13细胞c－myc基因的表达,探讨siRNA沉默c－myc对肾上腺皮质癌细胞增殖的影响。方法将siRNA－c－myc转染入SW－13细胞中,采用荧光定量PCR和Wes-tern blot检测转染后c－myc的表达,MTT分析SW－13细胞的增殖,荧光定量PCR检测转染后FHIT在SW－13细胞中的表达。结果 c－myc mRNA在转染48 h后明显下降,c－myc蛋白在转染72 h后明显下降。 SW－13细胞增殖能力在转染24 h后开始下降,48 h和72 h后受到明显抑制。沉默c－myc基因后,FHIT在SW－13细胞的表达有所升高。结论 siRNA沉默c－myc使肾上腺皮质癌细胞增殖受到抑制。 siRNA沉默c－myc基因为肾上腺皮质癌的靶向治疗提供新的理论依据。     

稳定表达HPV16 E6 siRNA细胞克隆的建立

目的构建针对HPV16 E6基因的逆转录病毒载体,感染HPV16阳性宫颈癌细胞,筛选稳定表达HPV16 E6 siRNA的细胞克隆。方法采用DNA重组技术构建表达靶向HPV16E6基因的pSUPER．retro RNAi逆转录病毒载体,脂质体法将逆转录病毒载体转染人包装细胞PA317,G418筛选稳定产生逆转录病毒的细胞克隆,收集病毒上清,感染靶细胞SiHa,G418筛选出稳定表达HPV16 E6 siRNA细胞克隆,RTPCR检测细胞中E6 mRNA表达,细胞增殖实验检测细胞增殖力。结果获及稳定产生逆转录病毒的细胞克隆,病毒感染靶细胞SiHa后,筛选出稳定表达HPV16 E6 siRNA的细胞克隆,RTPCR示HPV16 E6 mRNA表达受到抑制。细胞增殖实验示克隆细胞增殖率明显下降。结论成功建立稳定表达HPV16 E6 siRNA细胞克隆,特异性的siRNA能抑制细胞生长、HPV16 E6 mRNA表达,HPV16 E6 siRNA可能成为治疗宫颈癌的一种新方法。     

肾损伤因子-1在脂多糖诱导的HK-2细胞炎症反应中的作用

目的：分析肾损伤因子-1（KIM-1）在脂多糖（LPS）诱导HK-2细胞炎症模型中的表达并探讨其可能参与的生物学进程。方法：LPS刺激人肾小管上皮HK-2细胞诱导细胞炎症模型,CCK-8比色法分析LPS对HK-2细胞株体外生长的抑制作用;RT-PCR和Western blot实验分析KIM-1在正常组和LPS诱导组中的表达差异;设计siRNA靶向干扰KIM-1基因的表达,分析其对LPS诱导下HK-2细胞生长抑制作用的影响;Hoechst33342/PI双染法分析LPS诱导下对照组和siRNA干扰组细胞凋亡的影响。结果：50、100 μg/mL终浓度的LPS处理24 h和48 h后能抑制HK-2细胞增殖,与对照组比差异有统计学意义（P＜0.05）;KIM-1和IL-6基因和蛋白表达水平在LPS处理组中较对照组明显上调,且具有浓度依赖性,差异有统计学意义（P＜0.05）;LPS处理组中Hoechst33342染色阳性细胞比例明显高于对照组;siRNA转染组中KIM-1和IL-6基因和蛋白表达水平均明显低于siRNA-NC组,在LPS作用下siRNA转染组HK-2细胞增殖率明显高于siRNA-NC组,差异有统计学意义（P＜0.05）;在siRNA转染组中,Hoechst33342染色强度均低于siRNA-NC组,提示靶向KIM-1基因siRNA转染可以抑制LPS诱导的细胞凋亡作用。结论：LPS可以诱导HK-2细胞增殖受抑和凋亡,并且上调KIM-1和IL-6基因表达;KIM-1可能通过调节细胞凋亡和生长抑制过程参与细胞炎症反应。     

Exendin-4通过下调Wnt5a基因表达促进胰岛β细胞瘤INS-1细胞增殖

目的: 研究Exendin-4调控胰岛β细胞瘤INS-1细胞增殖的机制。方法: 使用Exendin-4刺激INS-1细胞,通过EdU标记染色法检测INS 1细胞增殖率变化,并采用实时半定量PCR法和蛋白质印迹法检测INS-1细胞Wnt5a基因和蛋白的表达。siRNA瞬时转染沉默INS-1细胞Wnt5a基因,通过EdU标记观察细胞增殖率变化。重组Wnt5a蛋白与Exendin-4共刺激INS-1后EdU标记观察细胞增殖率变化。结果： Wnt5a在INS-1细胞中基础表达丰度高,Exendin 4显著降低INS 1细胞Wnt5a基因mRNA及蛋白表达水平。siRNA-Wnt5a瞬时转染降低INS-1细胞增殖率。重组Wnt5a蛋白呈浓度依赖性拮抗Exendin 4对INS 1细胞的促增殖效应。 结论： Exendin-4通过下调Wnt5a基因表达促进INS 1细胞增殖。     

BIRC5基因沉默对人膀胱癌细胞系T24增殖抑制的研究

目的 探讨靶向抑制膀胱癌细胞系T24中BIRC5基因的表达后,该基因编码产物Survivin蛋白对膀胱癌增殖的影响.方法 将设计合成的靶向BIRC5序列的小分子干扰RNA(small interfering RNA,siRNA),转染膀胱癌细胞系T24,应用RT-PCR技术和Western blot方法检测目的基因转录及表达水平.通过生长曲线来检测survivin基因沉默后细胞增殖的改变.结果 特异性siRNA转染后,survivin mRNA及蛋白水平均明显下降.与空白对照组相比较,转染组细胞增殖情况明显受到抑制,差异具有统计学意义(P＜0.05).结论 特异靶向survivin的siRNA能有效抑制survivin的表达,显著抑制细胞的增殖,为膀胱癌的临床治疗提供新方向.     

siRNA对骨肉瘤细胞MDM2的表达及细胞增殖的抑制作用

目的: 研究siRNA对人骨肉瘤U20S细胞MDM2基因表达及肿瘤细胞增殖的抑制作用。 方法: 构建可表达针对MDM2的siRNA质粒(PGCsilencer^TM-MDM2-siRNA)。转染siRNA MDM2(简称siMDM2),阴性对照质粒到U20S,并设只加转染试剂作空白对照组,用逆转录聚合酶链反应(RT-PCR)和Western blotting法检测siMDM2对MDM2基因和蛋白表达的抑制作用,并用MTT法检测siMDM2对细胞增殖的抑制作用。 结果: RT-PCR结果显示,转染siMDM2-1和 -2组MDM2的mRNA表达量分别下调到空白对照组的32.61%和39.06%;Western blotting结果显示,转染siMDM2-1和 -2组蛋白表达量下调到空白对照组的35.76%和42.20%;转染阴性对照质粒的MDM2基因和蛋白与转染试剂组比较差异均无显著性(P>0.05)。MTT结果显示,转染siMDM2后细胞生长受到明显抑制,与转染试剂组比较差异具有显著性(P<0.05),阴性对照组抑制率与转染试剂组比较差异无显著性(P>0.05)。结论：siRNA可以有效地抑制U20S细胞中MDM2的表达,并抑制细胞增殖。