丙型肝炎病毒核心区蛋白对 HepG2细胞周期、细胞凋亡和细胞端粒酶活性的影响

目的　研究丙型肝炎病毒核心区 (HCV C)蛋白对肝癌细胞HepG2细胞周期、细胞凋亡和细胞端粒酶活性的影响。方法　首先运用基因重组技术构建含有HCV C基因的真核表达质粒pcDNA3.1( ) ,然后利用脂质体介导将重组真核表达质粒转染HepG2 ,经G4 18筛选获得稳定转染HepG2细胞 (HCV C转染HepG2细胞 ) ,经逆转录 聚合酶链反应技术 (RT PCR)和间接免疫荧光法证实其中有HCV C蛋白表达。然后进行如下实验 :( 1)利用四甲基偶氮唑蓝比色 (MTT)法检测HCV C转染HepG2细胞、空白质粒转染HepG2细胞和未转染HepG2细胞的生长增殖率 ;经流式细胞术(FACS)检测 3组细胞的细胞周期 ;( 2 )经流式细胞术检测细胞凋亡率 ;( 3)经端粒重复扩增 酶联免疫吸附试验 (TRAP ELISA)法检测上述 3组细胞端粒酶活性表达情况。结果　 ( 1)HCV C转染HepG2细胞增殖率显著高于空白质粒转染HepG2和未转染HepG2细胞增殖率 ;HCV C转染HepG2细胞S期所占百分率高于未转染HepG2细胞S期所占百分率 ;( 2 )HCV C转染HepG2细胞凋亡率显著低于无HCV C转染细胞凋亡率 ;( 3)上述 3组细胞端粒酶活性之间差异无显著性。结论　 ( 1)HCV C蛋白具有抑制细胞凋亡的作用 ;( 2 )HCV C蛋白促进HepG2从G0 /1期进入S期 ,从而可能促进细胞生长增殖 ,抑制细胞凋亡 ;( 3)HCV     

肝细胞中HBV X基因的表达及其共培养的肝星状细胞的增殖和迁移

目的:研究乙型肝炎病毒X(hepatitis B virus X,HBV X)基因在乙型肝炎病毒致肝纤维化中的作用.方法:构建HBV X基因真核表达载体pHBV-X-IRES2-EGFP,将其转染人肝细胞HL-7702后分成2组,一组经G418筛选出稳定表达HBVX基因的肝细胞株(L02/x),另一组予瞬时转染48 h(L02/48x).Real-time PCR、Western blot鉴定2组细胞HBV X基因的表达.与转染空质粒和未转染的肝细胞组对照,将L02/x和L02/48x细胞分别与肝星状细胞(hepatic stellate cells,HSCs)共培养36 h,并检测各组HSCs增殖和迁移情况.结果:Real-time PCR和Western blot实验显示,转染pHBV-X-IRES2-EGFP载体的L02/x和L02/48x细胞均有HBV X基因的表达.与转染空质粒和未转染的肝细胞组对照,与L02/x和L02/48x细胞共培养的HSCs的增殖和迁移均显著增多.结论:HBV X基因在肝细胞中的表达可以促进HSCs发生增殖和迁移,从而在乙型肝炎病毒致肝纤维化过程中起重要作用.     

乙型肝炎病毒X蛋白对肝细胞癌生长因子激活作用的研究

目的研究乙型肝炎病毒Ｘ（hepatitisBvirus,HBx）蛋白对生长因子激活作用,探讨HBx蛋白对肝细胞癌生长的影响。方法构建Ｘ基因真核表达载体,转染入HepG2细胞后,细胞组织化学和免疫印迹法检测胰岛素样生长因子－Ⅰ受体（insulin-likegrowthfactorⅠreceptor,IGF-ⅠR）和血管内皮生长因子（vascularendothelialgrowthfactor,VEGF）表达。结果转染HBx基因HepG2细胞（X细胞）IGF-ⅠR表达阳性率为84%±3%,转染空载体对照细胞（X0细胞）为26%±4%;免疫印迹法检测Ｘ细胞有明显条带。VEGF表达Ｘ细胞阳性率为83%±5%,X0细胞为28%±6%,差异有非常显著意义;Ｘ细胞IGF-ⅠR表达增高近1.5倍。结论HBx蛋白可同时激活IGF-ⅠR和VEGF,在肿瘤恶性生长、转移中起有重要作用。     

端粒酶逆转录酶基因反义寡核苷酸抑制肺癌细胞端粒酶活性和诱导细胞凋亡

目的 研究端粒酶逆转录酶（hTERT)基因反义寡核苷酸（ASODN）对肺癌细胞端粒酶活性和细胞凋亡的影响。方法 实验分为ASODN组、正义寡核苷酸（SODN）组和空白对照组,所用ASODN和SODN的浓度分别为10μmol/L,脂质体为16mg/L,采用端粒重复扩增法、逆转录－聚合酶链反应、Western Blot及流式细胞术分别观察各组端粒酶活性、hTERP mRNA和蛋白质表达以及细胞凋亡。结果 ASODN组显著下调或抑制肺癌细胞端粒酶活性和hTERT表达,但直到第21天才出现细胞凋亡增多。结论 端粒酶活性与hTERT表达密切相关。     

B和C基因型HBV核心蛋白促细胞凋亡的比较

目的:比较B,C两种基因型HBV核心蛋白在促进肝细胞凋亡方面的差异,以期初步阐述HBV基因型与临床关系的发病机制.方法:用PCR扩增4份(B和C基因型各2份)HBV-C区DNA片段,通过基因重组、分子克隆和亚克隆等方法,合成4份不同基因型和临床表型的重组真核表达质粒.鉴定后,将他们分别转染至肝癌细胞系HepG2中,采用MTT法和流式细胞仪测定转染细胞的细胞增殖率和细胞凋亡率等指标.结果:4份重组真核表达质粒均构建成功,转染至HepG2后通过内参照EGFP可鉴定出均有HBV-C蛋白表达.流式细胞仪提示C型/重型HBV转染组的细胞凋亡率显著高于B型/携带HBV转染组(8.8%±2.0%vs6.4%±0.8%,P<0.05).结论:C型HBV核心蛋白较B型HBV更能促进肝细胞凋亡,HBV基因型与临床相关性可能与此有关.     

热休克蛋白70通过Bcl-2抑制氧化应激所致C2C12细胞凋亡

目的 探讨C2C12肌原细胞内热休克蛋白70对Bcl-2表达的影响及Bcl-2对热休克蛋白70抗细胞凋亡作用的影响.方法 应用Western Blotting观察Bcl-2在转染热休克蛋白70真核表达质粒(pcDNA3.1-HSP70)或其反义寡核苷酸C2C12肌原细胞中的表达;采用基因瞬间转染技术使热休克蛋白70过表达的C2C12肌原细胞内Bcl-2表达抑制,应用流式细胞术检测H2O2处理所致细胞凋亡的发生情况.结果 转染热休克蛋白70真核表达质粒的C2C12肌原细胞中,热休克蛋白70和Bcl-2的表达明显高于空载体转染组(P<0.01);而转染热休克蛋白70反义寡核苷酸后,热休克蛋白70和Bcl-2的表达明显低于随机寡核苷酸转染组 (P<0.01);热休克蛋白70过表达的C2C12肌原细胞分别转染Bcl-2反义寡核苷酸及随机寡核苷酸,0.5 mmol/L H2O2处理24 h,Bcl-2反义寡核苷酸转染组的细胞凋亡率明显高于随机寡核苷酸转染细胞组.结论 热休克蛋白70能上调C2C12肌原细胞内Bcl-2的表达;热休克蛋白70的抗细胞凋亡功能可能与其上调Bcl-2表达相关.     

稳定表达乙型肝炎病毒X基因肝细胞株的构建

目的 构建稳定表达乙型肝炎病毒x基因（HBVx）的正常人肝细胞株。方法用PCR法扩增含EcoRI和HindⅢ酶切位点的x基因序列,构建HBVx基因真核表达载体pcDNA3．1（＋）-HBVx,转化大肠杆菌DHSct,筛选阳性克隆并对其进行双酶切和测序鉴定;用脂质体转染法将HBVx基因导入Chang细胞系,G418筛选,RT-PCR和Westernblot鉴定。结果x基因亚克隆入pcDNA3．1（＋）,含有完整的x基因片段,转染后Chang细胞有HBVxmRNA表达,Chang／HBVx有HBVx蛋白的表达。结论构建了稳定表达HBVx基因的肝细胞株Chang／HBVx。     

Chk1/2反义寡核苷酸对DDP诱导白血病原代细胞凋亡影响的研究

目的:观察白血病原代细胞在顺铂作用下细胞周期变化和转染Chk1/2反义寡核苷酸对顺铂诱导原代细胞凋亡的影响。方法:用RT-PCR、westernblot及免疫组化检测白血病骨髓单个核细胞(BMMNC)中Chk1和Chk2的表达,用流式细胞仪检测顺铂作用下白血病BMMNC细胞周期变化。以脂质体作为载体,转染Chk1/2反义寡核苷酸于BMMNC,用流式细胞仪检测转染Chk1/2反义寡核苷酸后顺铂作用下BMMNC细胞凋亡率。结果:在白血病BMMNC中,Chk1和Chk2mRNA水平均存阳性表达,Chk1蛋白表达强,而Chk2蛋白表达弱。10μmol/L顺铂作用下BMMNC出现S期阻滞,转染Chk1反义寡核苷酸可明显增加顺铂诱导下BMMNC凋亡率,转染Chk2反义寡核苷酸不能增加顺铂诱导下BMMNC凋亡率。结论:Chk1可作为白血病增敏治疗的有效靶点。     

乙型肝炎病毒X蛋白对肝癌细胞热休克蛋白90α基因表达的影响

乙型肝炎病毒X蛋白(HBx)与肝细胞癌的发生高度相关.我们前期研究发现,热休克蛋白(heat shock protein,HSP)90α在转染HBV X基因的人肝癌HepG2细胞中异常过表达[1].     

胃癌相关基因GCRG213真核表达载体的构建及其对胃癌细胞MKN45的影响

目的 研究胃癌相关基因GCRG213正义、反义转染对胃癌细胞MKN45的影响.方法 采用分子克隆及基因转染技术将GCRG213基因转入哺乳动物细胞,并结合反义转染技术研究GCRG213基因对胃癌细胞恶性生物学行为的影响.结果结果 GCRG213正向和反向克隆正确插人真核表达载体pcDNA3.1(+);重组子pcDNA3.1-a、pcDNA3.1-b和空载体转染人胃癌细胞系MKN45细胞;正义转染其mRNA的表达上调,而反义转染下调;正义转染加快MKN45细胞生长增殖速度、降低细胞凋亡率,反义转染减慢MKN45细胞生长增殖速度,增加细胞凋亡率.结论 胃癌相关基因GCRG213可促进肿瘤细胞生长、分裂和转移,抑制肿瘤细胞的凋亡,可能是一个新发现的恶性肿瘤癌变的促进因素.     

乙型肝炎病毒x蛋白对肝细胞FasL表达的激活作用

目的探讨ＨＢｘ蛋白对肝细胞Ｆａｓ配基（ＦａｓＬ）表达的调控作用。方法构建ＨＢｘ基因的真核表达载体ｐＣＥＰ４ｘ,电击法转染ＨｅｐＧ２细胞,潮霉素筛选阳性克隆细胞ＨｅＰＧ２Ｘ。用免疫细胞化学染色和免疫蛋白印迹法检测转染ＨＢｘ基因的ＨｅｎＧ２ｘ细胞ＦａｓＬ蛋白的表达。结果逆转录ＰＣＲ祛分析表明,ＨＢｘ基因在转染细胞内可有效转录;ＨｅｐＧ２ｘ细胞出现新的ＦａｓＬ蛋白表达。结论乙肝病毒ｘ蛋白可激活肝细胞表达ＦａｓＬ。     

The Retrovirus-mediated Antisense Human Telomerase RNA (hTR) Gene Limits the Growth of Hepatocellular Carcinoma Growth in Cell Culture and Animals

Aim To investigate the inhibitory effect of retrovirus-mediated antisense human telomerase RNA (hTR) gene therapy on hepatocelluar carcinoma. Methods We first constructed the sense and antisense hTR vectors and then transfected these into HepG2 cells. Telomerase activity, cell growth curves, proliferating cell nuclear antigen expression (PCNA), cell cycle distribution, and cell apoptosis were detected by the means of telemere repeat amplification protocol (TRAP), MTT assay, immunofluorescence, flow cytometric analysis, and transferase-mediated nick end labeling (TUNEL), respectively. In order to further confirm the therapeutic effect of this gene therapy, we developed an experimental line of HepG2 tumor-bearing nude mice by and directly injected these with retrovirus expressing the antisense hTR gene. Tumor growth was determined by tumor volume, and cell apoptosis was analyzed by TUNEL. Results The antisense hTR gene was shown to be successfully integrated into the target cells’ genome. HepG2 cells transfected with the antisense hTR gene showed down-regulated telomerase activity, inhibited cell growth, decreased PCNA expression, and increased apoptotic rate. Moreover, flow cytometry revealed a decrease of cells in the S phase with cell cycle arrest at the G2/M phase. In the antisense hTR-treated group, tumor growth was significantly reduced and showed an increase of apoptotic cells. Conclusion The results indicate that the specific inhibitor of the hTR template is likely to be a very efficient tool for hepatocellular carcinoma research and may possess potential therapeutic significance in the future clinical practice.     

Inhibition of human telomerase in MKN—45 cell line by antisense hTR expression vector induces cell apoptosis and growth arrest

AIM: To investigate the effects of antisense human telomerase RNA (hTR)on the biologic behavior of human gastric cancer cell line: MKN-45 by gene transfection and its potential role in the gene therapy of gastric cancer. METHODS: The hTR cDNA fragment was cloned from MKN-45 through RT-PCR and subcloned into eukaryotic expression vector (pEF6/V5-His-TOPO) in cis-direction or trans-direction by DNA recombinant methods. The constructed sense, antisense and empty vectors were transfected into MKN-45 cell lines separately by lipofectin-mediated DNA transfection technology. After drug selection, the expression of antisense hTR gene in stable transfectants and normal MKN-45 cells was detected by RT-PCR, the telomerase activity by TRAP, the apoptotic features by PI and Hoechst 33258 staining, the cell cycle distribution by flow cytometry and the population doubling time by cell counting. Comparison among the stable transfectants and normal MKN-45 cells was made. RESULTS: The sense, antisense hTR eukaryotic expression vectors and empty vector were successfully constructed and proved to be the same as original design by restriction endonuclease analysis and sequencing. Then, they were successfully transfected into MKN-45 cell lines separately with lipofectin. The expression of antisense hTR gene was only detected in MKN-45 cells stably transfected with antisense hTR vector (named as MKN-45-ahTR) but not in the control cells. In MKN-45-ahTR, the telomerase activity was inhibited by 75%, the apoptotic rate was increased to 25.3%, the percentage of cells in the G0/G1 phase was increased to 65%, the proliferation index was decreased to 35% and the population doubling time was prolonged to 35.3 hours. However, the telomerase activity, the apoptotic rate, the distribution of cell cycle, the proliferation index and the population doubling time were not different among the control cells. CONCLUSION: Antisense hTR can significantly inhibit telomerase activity and proliferation of MKN-45 cells and induce cell apoptosis. Antisense gene therapy based on telomerase inhibition can be a potential therapeutic approach to the treatment of gastric cancer.     

乙型肝炎病毒X基因下调miR-192对人肝癌细胞株HepG2凋亡的影响

目的 探讨乙型肝炎病毒X基因(HBx)通过调节人肝癌细胞株HepG2中miR-192的表达而抑制其凋亡的机制.方法 设立3个细胞组:稳定转染HBx基因的HepG2细胞(HepG2/HBx),稳定转染空载体pcDNA3.1的HepG2细胞(HepG2/pcDNA3.1)以及未作转染的HepG2细胞.用流式细胞术分析3个细胞组的凋亡率差异,用Taqman探针荧光定量PCR检测3组细胞中miR-192的表达水平.转染miR-192后,用流式细胞术检测HepG2细胞凋亡率的变化,同时用SYBR Green荧光定量PCR和Western blot检测细胞中p53、PUMA表达的变化.计量资料均数的比较用单因素方差分析.结果 HepG2/HBx细胞的凋亡率为2.37％±0.35％,较HepG2/pcDNA3.1、HepG2细胞(11.46％±0.69％、12.50％±0.66％)明显降低(F=171.722,P＜0.01).miR-192表达在HepG2/HBx细胞中为49.1％±5.9％,较HepG2/pcDNA3.1、HepG2细胞(98.0％±8.9％,100％)也明显下调(F=14.319,P＜ 0.05).转染miR-192后HepG2细胞的凋亡率(15.74％±1.17％)较转染相应阴性对照的HepG2细胞的凋亡率(10.74％±1.15％)显著升高(F=18.415,P＜0.05),同时,p53、PUMA基因在mRNA (953:1.68±0.12比0.90±0.09,F=43.115,P＜0.05 ; PUMA:1.66±0.10比0.98±0.06,F=22.541,P＜0.05)和蛋白质水平(p53:3.07比1,PUMA:2.13比1)的表达均显著上升.结论 miR-192促进HepG2细胞凋亡,HBx通过下调miR-192抑制HepG2细胞凋亡.     

Antisense hTERT inhibits thyroid cancer cell growth

Activation of telomerase represents an early step in carcinogenesis. Increased telomerase expression in malignant thyroid tumors suggests that inactivation of telomerase may represent a potential chemotherapeutic target. The purpose of this study was to inhibit the protein component of telomerase, hTERT, in a human thyroid cancer cell line in vitro and in vivo using an antisense strategy. A 235-bp fragment of hTERT cDNA was subcloned, and sense and antisense hTERT expression vectors were constructed. These vectors were transfected into a human thyroid carcinoma cell line (FRO). Tumorigenic potential was determined by cellular growth assay, rate of apoptosis, anchorage-independent growth, and tumor growth in a nude mouse model. Significant down-regulation of hTERT expression was seen in the antisense transfected cells, compared with control and those transfected with the sense vector. A decrease in telomerase activity by TRAP assay was observed in the antisense hTERT cells but not in cells transfected with the sense hTERT construct. Inhibition of cell growth was observed after approximately 20 population doublings in the antisense-hTERT clones and was associated with an increase in the rate of apoptosis and a change in cellular morphology. Moreover, anchorage-independent growth was reduced in vitro, and tumor growth rate was diminished in vivo in the antisense hTERT clones. Inhibition of telomerase activity with antisense hTERT in human thyroid cancer cells is achievable and may represent a novel target to inhibit tumor growth.     

乙型肝炎病毒HBx蛋白抑制阿霉素诱导的HepG2细胞凋亡

目的探讨乙型肝炎病毒HBx蛋白对阿霉素诱导的肝癌细胞凋亡的影响。方法将adr亚型HBx基因片段定向插入绿色荧光蛋白（GFP）真核表达载体pEGFPCl，构建重组体pGFP—HBx。将pEGFPCl、pGFPHBx转染HepG2细胞，采用G418筛选抗性克隆、荧光显微镜观察及RT—PCR检测HBx基因表达情况以建立稳定表达细胞株HepG2／GFP、HepG2／GFPHBx。用阿霉素（2．5μg／m1）分别处理HepG2、HepG2／GFP、HepG2／GFPHBx细胞，处理后不同时间在显微镜下观察细胞形态变化，并用锥虫蓝染色计数死亡细胞；流式细胞仪检测阿霉素处理36h后细胞凋亡率。结果HepG2／GFP、HepG2／GFPHBx细胞传70代后，仍表达强的GFP；RTPCR检测显示在HepG2／GFP—HBx细胞有HBx基因转录表达。锥虫蓝染色检测表明阿霉素处理的HepG2、HepG2／GFP细胞发生了明显的时间依赖性细胞死亡，而在HepG2／GFPHBx和对照组细胞未见明显细胞死亡；流式细胞仪检测显示阿霉素处理36h后，HepG2／GFP—HBx细胞凋亡率为3．94％，明显低于HepG2（59．03％）、HepG2／GFP细胞（61．38％）（P〈0．01），而与未处理对照组细胞凋亡率（2．12％，2．78％，2．55％）差异无统计学意义（P〉0．05）。结论成功建立了稳定表达GFP、GFPHBx的HepG2细胞株；HBx能够抑制阿霉素诱导的HepG2细胞凋亡。