人端粒酶催化亚单位锤头状核酶诱导肝癌细胞凋亡的作用

目的 构建带有U6启动子的人端粒酶催化亚单位锤头状核酶真核表达质粒及其突变体,转染入肝癌细胞株SMMC7721,观察端粒酶活性、细胞增殖和凋亡的情况。 方法 用分子克隆技术构建由U6作为启动子、绿色荧光蛋白基因作为报告基因的核酶真核表达质粒pGTRz-U6及其突变体pGTmRz-U6,并以空质粒pEGFP-C1作为对照。Lipofectamine2000转染人肝癌细胞株SMMC7721,G418筛选阳性克隆。RT-PCR检测核酶及hTERT基因的表达,四甲基偶氮唑盐(MTT)作细胞生长曲线观察其生长情况,TRAP-银染法检测端粒酶活性变化,流式细胞计数(FCM)法检测细胞的凋亡水平。 结果 核酶、突变核酶在SMMC7721中持续表达;凝胶成像系统分析SMMC7721-pEGFP-C1、SMMC7721-mRz、SMMC7721-Rz hTERT基因表达,用SPSS10.0软件对3种细胞进行分析,发现三者hTERT基因表达水平不同(F=47.987,P<0.01);t检验分析得出SMMC7721-Rz hTERT基因表达明显低于SMMC7721-mRz和SMMC7721- pEGFP-C1(t值分别为-7.640和-11.602,P值均<0.01)。SMMC7721-pEGFP-C1和SMMC7721-mRz hTERT表达没有区别(t=-0.178,P>0.05)。TRAP-银染及FCM结果分别显示,随着细胞的分裂,SMMC7721-Rz和SMMC7721-mRz细胞端粒酶活性逐渐降低,凋亡水平逐渐增加,7PDS细胞凋亡率分别是29.86％和9.87％,而对照组SMMC     

离散因子/肝细胞生长因子cDNA转染对肝癌SMMC7721细胞生长和转移的影响

目的 通过离散因子／肝细胞生长因子（scatter factor/Hepatocyte factor,SF/HGF）cDNA转染肝癌SMMC7721细胞来探讨SF／HGF对肝癌生长和转移的影响。方法 用脂质体法进行基因转染,以ELISA和western blot检测SF／HGF及其受体c-met的表达,通过生长曲线、划良实验比较转染前后细胞的增长状况及细胞的运动能力。以转染前后细胞分别接种裸鼠,观察移植的生长及转移情况。结果 转染后细胞表达SF／HGF的量为694pg/ml,其受体c-met量未见明显变化;转染后细胞增殖明显加快,运动能力增强,并伴明显的形态学变化。初步动物实验显示转染后细胞生长较快,瘤组织中有瘤栓形成,并在肺内发现转移灶。结论 SF／HGF在肝癌细胞中的高表达能促进肝癌细胞生长、侵袭及转移。     

血管内皮细胞生长因子反义核糖核酸对肝癌细胞生长的抑制作用

目的 探讨血管内皮细胞生长因子(VEGF)反义RNA转染人肝癌细胞后对细胞体内外生物学性状的影响。方法 将含正义、反义VEGFcDNA序列的质粒PCMV—VEGF、PCMV—FGEV及空载体质粒pcDNA3.1,在脂质体介导下导入SMMC—7721肝癌细胞,分别称为正义、反义及对照组,并通过G418筛选获得阳性克隆。细胞原位杂交和免疫组织化学方法检测转染后VEGF在肝癌细胞内的表达情况;MTT法和FCM检测转染后细胞在体外的增殖和凋亡情况;并制备裸鼠动物模型,观察转染后细胞的体内生长情况。结果 转染PCMV—FGEV后肝癌细胞内VEGF的转录及其蛋白的表达水平显著下降,但转染后体外细胞的增殖与凋亡情况均无明显变化。转染PCMV—FGEV后细胞在裸鼠体内的生长缓慢,反义组成瘤时间为(25.0±1.8)d,明显长于正义组(15.7±2.5)d和对照组(18.5±2.1)d,F=19.455,P<0.01;而平均瘤重以反义组最轻,为(0.96±0.28)g,F=21.501,P<0.01;同时反义组裸鼠肿瘤细胞发生明显的凋亡。结论 VEGF反义RNA转染人肝癌细胞可抑制肿瘤细胞VEGF的表达,在体外对细胞增殖和凋亡无影响,而体内可显著诱导细胞凋亡并抑制肿瘤生长。     

survivin反义寡核苷酸转染肝癌细胞可诱导caspase-3活化

目的:观察survivin反义寡核苷酸(antisense oligonucleotide,AS ODN)诱导肝癌细胞凋亡的可能途径。方法:培养survivin表达阳性的肝癌细胞株SMMC-7721。设计合成特异性靶向survivin的反义寡核苷酸。将SMMC-7721细胞接种于6孔培养板内,分为6组:①空白对照组;②脂质体转染对照组;③正义链转染对照组;④200nmol/L AS ODN转染组;⑤400nmol/L AS ODN转染组;⑥600nmol/L AS ODN转染组。作用20小时后收获各组细胞,并进行后续实验:①倒置显微镜下观察细胞形态变化;②western blot法检测各组细胞survivin蛋白的表达情况;③流式细胞术检测细胞增殖和凋亡指数;④比色法检测各组细胞caspase-3的活性变化。结果:①AS ODN转染组细胞survivin表达减弱,以600nmol/L转染组最为明显,各对照组survivin蛋白表达无明显改变;②AS ODN转染组细胞形态出现变圆、折光增强、漂浮、细胞碎片形成等变化,而各对照组细胞生长良好;③各AS ODN转染组细胞凋亡指数明显高于各对照组(P<0.05),以600nmol/L转染组最为明显,而各对照组间差异无显著性意义(P>0.05);④各AS ODN转染组细胞增殖指数明显低于各对照组(P<0.05),以600nmol/L转染组最为明显,而各对照组间差异无显著性意义;⑤在各AS ODN转染组中,可见到不同程度的caspase-3的活化,而对照组细胞内无明显的变化。结论:survivin AS ODN转染能下调survivin蛋白表达,诱导肝癌细胞凋亡,抑制细胞增殖,其作用途径可能涉及抑制survivin表达,诱导caspase-3活化,启动凋亡信号传导。     

反义c-myc寡核苷酸对转染FHIT基因胃癌细胞MKN28的影响

目的: 探讨脂质体介导的c-myc反义寡核苷酸对导入脆性组氨酸三联体(FHIT)基因的胃癌细胞增殖及凋亡的影响.方法: 通过脂质体将重组FHIT基因PRC/CMV质粒和空载体转染到人类胃癌细胞系MKN28,并分别转染c-myc反义寡核苷酸,RT-PCR和Westen b1ot法检测FHIT基因的转染,Westem b1ot法检测细胞c-mHyc的表达,MTT法分析细胞增殖,AO/EB染色法和流式细胞分析技术检测细胞凋亡.结果: 转染FHIT基因后,MKN28细胞检测到FHIT基因片段和FHIT蛋白,而未转染的细胞及转染空载体的细胞未检测到FHIT基因片段及FHIT蛋白.转染c-myc反义寡核苷酸后.对MKN28细胞c.myc的表达有明显的抑制作用,并呈明显的时间依赖性;c-myc asODN对FHIT MKN28细胞抑制率(F=177.480,P<0.05),凋亡率(F=41.500,P<0.05)和凋亡比例明显高于FHIT MKN28细胞.结论: 癌基因c-myc的表达抑制联合FHIT基因的表达可以发挥较强的抗肿瘤细胞作用,为多基因治疗肿瘤提供了理论基础.     

Bcl-2核酶对SMMC7721细胞的促凋亡机制

目的 观察Bel-2核酶对SMMC-7721细胞的作用,探讨bcl-2抑制细胞凋亡的机制。方法 经脂质体介导的方法将PMTr-neo(正向Bcl-2核酶真核表达载体)导入SMMC 7721细胞中．细胞克隆转移扩大培养后,采用TUNEL,TRAP结合ELISA流式细胞仪,免疫组化技术检测SMMC 7721／PMTr-neo细胞增殖及细胞凋亡。结果 较对照组SMMC 7721／PMTr-neo细胞bcl-2表达水平显著下降,伴有显著细胞凋亡现象及端粒酶活性下降,结论 Bcl-2核酶可促进SMMC 7721细胞发生凋亡,并降低细胞端粒酶活性,为反义技术在肝癌治疗中应用提供理论依据。     

膜-细胞骨架联接分子ezrin对肝癌细胞系生长和侵袭能力的影响

目的探讨膜-细胞骨架联接蛋白ezrin在肝细胞肝癌生长和转移过程中的作用。方法分别应用免疫荧光、逆转录聚合酶链反应（RT—PCR）和Western blot检测ezrin和骨架蛋白在不同转移潜能肝癌细胞系中的表达。选取高转移潜能SF7721（SMMC-7721经转基因后稳定表达肝细胞生长因子，从而获得高转移潜能的细胞系）和MHCC97-H细胞系为研究对象。通过RNA干扰技术下调SF7721和MHCC97-H细胞系中ezrin蛋白的表达，观察其运动和侵袭能力的变化：通过四甲基偶氮唑盐检测细胞增殖能力变化；电子显微镜观察细胞伪足；Transwell检测细胞的运动侵袭能力。结果免疫荧光显示ezrin和骨架蛋白表达于细胞质，且双色荧光证实两者存在共表达，高转移潜能细胞系SF7721。MHCC—I、MHCC97-Hezrin和骨架蛋白的表达明显高于低转移潜能细胞系SMMC-7721、Hep3B、HepG2细胞（x^2=13．277，P=0．010；x^2=21．815，P〈0．01）。D-肌动蛋白在高低转移潜能细胞系的表达差异无统计学意义。通过RNA干扰技术抑制ezrin蛋白表达后。SF7721和MHHC97-H的细胞的增殖和侵袭能力均显著下降。结论ezrin和骨架蛋白的过表达与肝癌的转移潜能相关，通过下调ezrin的表达可明显抑制肝癌细胞系SMMC-7721和MHCC97-H细胞的增殖和运动侵袭能力。     

缺氧环境中黏着斑激酶对SMMC-7721细胞侵袭能力的影响

目的 研究缺氧对人肝癌细胞SMMC-7721黏着斑激酶(FAK)表达的影响以及FAK表达对SMMC-7721细胞侵袭能力的影响.方法 通过1%体积分数O2的低氧培养建立人肝癌细胞SMMC-7721物理缺氧模型,Western blot检测FAK的表达.构建针对FAK mRNA的干扰质粒pshRNA-FAK及阴性对照质粒pGensil-2,并将其转染至SMMC-7721细胞,G418筛选稳定转染细胞株.Western blot检测FAK蛋白表达的变化,细胞迁移和侵袭实验检测缺氧条件下细胞迁移和侵袭能力的改变.在正常条件下将FAK真核表达质粒pcDNA3-FAK转染至SMMC-7721细胞,观测其侵袭能力的改变.根据数所资料的不同分别采用t检验、单因素方差分析,LSD法及Dunnett法进行统计学处理. 结果低氧培养的SMMC-7721细胞FAK蛋白表达水平逐渐升高,24 h后较0 h时明显升高(P<0.01).SMMC-7721细胞稳定转染pshRNA-FAK后,FAK蛋白表达显著下降,抑制率达74.6%±5.1%,在正常及缺氧条件下都对FAK表达有显著抑制作用.细胞迁移实验结果显示,缺氧显著促进SMMC-7721细胞迁移能力(t=18.66,P<0.01),侵袭实验结果与迁移实验结果一致.转染pshRNA-FAK对促进SMMC-7721细胞在缺氧环境中的迁移能力有显著抑制作用,透膜细胞数(353±36)个较对照组(392±31)个明显降低(F=173.983,P<0.05);细胞侵袭实验显示,转染pshRNA-FAK对促进SMMC-7721细胞侵袭能力有显著抑制作用,透膜细胞数(160±12)个较对照组(194±13)个明显降低(F=59.674,P<0.05).同时转染真核表达质粒pcDNA3-FAK显著促进SMMC-7721细胞侵袭能力.结论 缺氧促进SMMC-7721细胞侵袭可能与FAK表达水平升高相关,FAK表达的上调可能是缺氧促进肝癌细胞侵袭转移的机制之一.     

变异IκBα抑制肝癌细胞株SMMC-7721中NF-κB活性及细胞生长

目的 了解变异IκBα(mIκBα)转染到肝癌细胞株SMMC-7721细胞中是否抑制NF-κB向核内转位活性及细胞的生长。 方法 电泳迁移率分析检测32p标记的寡核苷酸探针与NF-κB结合情况,westernblot检测核内NF-κB表达情况,细胞生长曲线分析和细胞增殖实验分析肝癌细胞生长情况。 结果 转染mIκBα质粒肝癌细胞在0、24、48、96 h未见核内蛋白与κ B探针结合转染,而转染对照PcDNA3质粒肝癌细胞始终可见核内蛋白与κB探针强结合;Western blot结果也显示0、24、48、96 h未见核内NF-κB表达,而对照PcDNA3质粒核内NF-κB高水平表达。细胞增殖实验分析发现转染mIκBα质粒肝癌细胞生长受到抑制,而转染对照PcDNA3质粒肝癌细胞生长未受影响,第2天开始转染mIκBα质粒肝癌细胞与其它两种细胞比较差异有非常显著性,增殖效率值分别是5 092.63±541.41、7 851.87±72.76、8 240.88±603.26,t值分别是14.29、10.99,P<0.01。 结论 转染mIκBα质粒肝癌细胞可以持续表达mIκBα,抑制NF-κB向核内转位,从而抑制肿瘤细胞的生长。     

骨桥蛋白促进人肝癌细胞株SMMC-7721恶性表型的实验研究

目的研究骨桥蛋白(OPN)对低侵袭性人肝癌细胞株SMMC-7721恶性表型的影响。方法pcDNA 3,1(-)/OPN重组质粒转染SMMC-7721细胞,以空质粒转染作对照,用RT- PCR反应、Western blot检测OPN表达水平,用ELISA检测细胞培养上清液OPN、MMP-2、-9、尿激酶纤溶酶原活化因子(uPA)水平,并用体外功能试验观察转染前后恶性表型的变化。结果重组质粒转染SMMC-7721后OPN表达明显升高,细胞培养上清液OPN为(3.02±0.12)ng/ml,对照组为(1.43±0.07)ng/ml,MMP-2重组质粒转染组为(43.04±3.06)ng/ml,对照组为(22.15±4.34)ng/ml、uPA重组质粒转染组水平明显高于空质粒转染组,分别为(4.78±0.70)ng/ml和(1.61±0.34)ng/ml,两组差异均有统计学意义,t值分别为19.89、6.81和7.03,P值均<0.01。MMP-9水平分别为(7.82±2.25)ng/ml和(7.70±1.92)ng/ml,两组差异无统计学意义。体外功能试验提示SMMC-7721转染OPN重组质粒后细胞黏附、运动和侵袭能力明显增强,细胞黏附率为75.33%±10.59%,对照组为57.34%±2.52%,t=2.86,P<0.05。运动试验透膜细胞数分别为(14.3±2.5)个和(6.3±1.5)个,t=4.70,P<0.05。侵袭试验透膜细胞数分别为(8.2±1.5)个和(4.1±1.3)个,t=4.11,P<0.05。而细胞增殖能力无明显改变。结论OPN可能是通过增加MMP-2、uPA分泌促进人肝癌细胞株SMMC-7721的恶性表型。     

Inhibitory effect of antisense vascular endothelial growth factor RNA on the profile of hepatocellular carcinoma cell line in vitro and in vivo

AIM:To evaluate the effect of antisense vascularendothelial growth factor(VEGF)RNA(PCMV-FGEV)transfection on the profile of hepatocellular carcinoma(HCC)SMMC-7721 cells in vitro and in vivo.METHODS:SMMC-7721 cells were transfectedwith PCMV-FGEV antisense,PCMV-VEGF sense andempty vector plasmid encapsulated by lipofectamineas antisense group,sense group and control grouprespectively.The positive cell clones were selectedwith G418.The stable transfection and expressionof VEGF in the cells were determined by RT-PCR andimmunohistochemistry.Cell proliferation was observedby MTT assay.FACS analysis was used to determine theeffect of PCMV-FGEV transfection on cell apoptosis.Thegrowth of transfected cells in Wvo was also observed innude mice.RESULTS:VEGF expression was reduced in SMMC-7721transfected with PCMV-FGEV,which was confirmed byRT-PCR and immunohistochemistry.No effect of PCMV-FGEV transfection was found on cell proliferation andcell apoptosis of SMMC-7721 in vitro.The growth of cellstransfected with PCMV-FGEV was slow in nude miceand accompanied with obvious apoptosis.The latenttime of tumors in the antisense group was 25.0±1.8d,which was longer than that in sense and controlgroups(F=19.455,P<0.01).The average tumor weightin antisense group(0.96 g±0.28 g)was the smallestamong the three groups(F=21.501,P<0.01).CONCLUSION:The expression of VEGF can be inhibitedby antisense PCMV-FGEV.Antisense PCMV-FGEV has no effect on cell proliferation and apoptosis of SMMC-7721in vitro but can inhibit tumor growth and induce cellapoptosis in vivo.     

Effects of insulin-like growth factors-IR and -IIR antisense gene transfection on the biological behaviors of SMMC-7721 human hepatoma cells

BACKGROUND AND AIMS: Insulin-like growth factors (IGFs) are closely related to hepatocellular carcinoma growth. The study aim was to investigate the effects of IGF-IR and IGF-IIR antisense gene transfection on the biological behaviors of SMMC-7721 human hepatoma cells. METHODS: 7721-IGF-IR-AS cells (human hepatoma SMMC-7721 cells transfected with IGF-IR antisense gene in our previous study) were transfected with a plasmid vector expressing IGF-IIR cDNA in the antisense orientation by DOTAP liposome.7721-IGF-R-AS cells were obtained by selection with G418 and hygromycin. Morphological changes of the cells were observed with optic and electron microscopes. In vitro growth of the 7721-IGF-R-AS cells was observed with a soft agar test, MTT test and with naked mice inoculation test in vivo. RESULTS: The following changes were found in the SMMC-7721 cells after being transfected with the IGF-IR and IGF-IIR antisense genes: (i) the degree of malignancy of the tumor cells as revealed by cell morphology was ameliorated; (ii) the growth capability of the tumor cells in soft agar and their tumorigenicity in naked mice were significantly depressed. However, in the control groups, the SMMC-7721 cells transfected both with IGF-IR and IGF-IIR sense cDNA and SMMC-7721 cells transfected without any external genes, had no such changes. However, the cell growth curves had no significant differences among these three groups. CONCLUSION: IGF-IR and IGF-IIR antisense genes could significantly restrain the malignant behavior of human hepatoma cells and might be useful in investigating a potential route for hepatocellular carcinoma gene therapy.     

Reduction of tumorigenicity of SMMC-7721 hepatoma cells by vascular endothelial growth factor antisense gene therapy

AIM To test the hypothesis to block VEGFexpression of SMMC-7721 hepatoma cells mayinhibit tumor growth using the rat hepatomamodel.METHODS Amplifiy the 200 VEGF cDNAfragment and insert it into human U6 genecassette in the reverse orientation transcribingsmall antisense RNA which could specificallyinteract with VEGF165, and VEGF121 mRNA.Construct the retroviral vector containing thisantisense VEGF U6 cassette and package thereplication-deficient recombinant retrovirus.SMMC-7721 cells were transduced with thesevirus and positive clones were selected withG418. PCR and Southern blot analysis wereperformed to determine if U6 cassette integratedinto the genomic DNA of positive clone,Transfected tumor cells were evaluated for RNAexpression by ribonuclease protection assays.The VEGF protein in the supernatant of parentaltumor cells and genetically modified tumor cellswas determined with ELISA. In vitro and in vivogrowth properties of antisense VEGF cell clonein nude mice were analyzed.RESULTS Restriction enzyme digestion andPCR sequencing verified that the antisense VEGFRNA retroviral vector was successfullyconstructed. After G418 selection, resistantSMMC-7721 cell clone was picked up, PCR andSouthern blot analysis suggested that U6cassette was integrated into the cell genomic DNA. Stable SMMC-7721 cell clone transducedwith U6 antisense RNA cassette could express200bp small antisense VEGF RNA and secretereduced levels of VEGF in culture condition.Production of VEGF by antisense transgene-expressing cells was 65±10 ng/L per 10~6 cells,420±45 ng/L per 10~6 cells in sense group and 495±30 ng/L per 10~6 cells in the negative controlgroup, (P<0.05), The antisense-VEGF cellclone appeared phenotypically indistinguishablefrom SMMC-7721 cells and SMMC-7721 cellstransfected sense VEGF. The growth rate of theantisense-VEGF cell clone was the same as thecontrol cells. When S. C. was implanted intonude mice, growth of antisense-VEGF cell lineswas greatly inhibited compared with controlcells.CONCLUSION Expression of antisense VEGFRNA in SMMC-7721 cells could decrease thetumorigenicity, and antisense-VEGF genetherapy may be an adjuvant treatment forhepatoma.     

miR-144脂质体复合物体外抑制肝癌细胞增殖和侵袭能力及对裸鼠种植肿瘤的抑制作用初步研究*

目的 研究mi-RNA-144脂质体复合物对HepG2和SMMC-7721细胞增殖、迁移和侵袭的影响,并观察其在体内的抑瘤作用。方法 通过薄膜分散法制备DOTMA阳离子脂质体,与miR-144孵育得到miR-144脂质体复合物,通过摄取和转染实验确定DOTMP脂质体与miR-144的体积质量比;观察miR-144脂质体复合物对HepG2和SMMC-7721细胞杀伤、迁移和侵袭能力的影响。在裸鼠肝脏种植肿瘤模型,观察miR-144脂质体复合物的抑瘤作用。结果 选择DOTMP脂质体与miR-144的体积质量比为3:1,得到的miR-144脂质体复合物粒径在200 nm左右,其多分散性指数（PDI）小于0.3;DOTMP脂质体与质粒的体积/质量比（μl/μg）为3:1时,转染效率最高（P<0.05）;随着孵育时间的延长,miR-144脂质体复合物对SMMC-7721细胞和HepG2细胞的杀伤作用均增强（P<0.05）;经miR-144脂质体复合物处理过的HepG2细胞和SMMC-7721细胞迁移和侵袭距离均显著缩短（P<0.01）;与对照组比,经过miR-144脂质体复合物处理的肿瘤细胞接种肿瘤直径显著缩小（P<0.05）。结论 miR-144脂质体能够在体外和体内抑制肝癌细胞的侵袭,具有很大的应用前景。     

多药耐药基因反义寡核苷酸逆转肝癌细胞耐药的研究

目的 观察反义硫代磷酸酯寡核昔酸(AsODN)联合逆转耐药肝癌细胞多药耐药基因1(MDR1)和多药耐药相关蛋白基因(MRP)的作用。 方法 用人工合成互补于MDR1基因及MRP基因的反义20聚硫代磷酸寡核苷酸,以脂质体作载体,转染入耐阿霉素(ADM)肝癌细胞SMMC-7721/ADM,四甲基偶氮唑蓝法测定细胞对化学疗法药物的敏感性,流式细胞仪分析细胞相对荧光强度,激光扫描共聚焦显微镜测定细胞内Rhdaming123(Rh123)及柔红霉素(DNR)潴留以反映蛋白质p170和p190功能。 结果 ASODN/MDR1 MRP联合转染SMMC-7721/ADM细胞,能更大程度增加细胞对ADM(47.8倍)和DNR(21.6倍)的敏感性。ASODN/MDR1 MRP联合转染SMMC-7721/ADM细胞,与单独任一种ASODN转染相比,对p170或p190表达的抑制并不增加(q值分别为3.23、3.24,P>0.05)。 结论 针对MDR1 MRP的ASODN联合转染SMMC-7721/ADM细胞,能更大程度逆转肝癌细胞的耐药性。