抗端粒酶模板区核酶诱导鼻咽癌细胞凋亡的实验研究

目的 :研究端粒酶RNA模板区特异性核酶对人低分化鼻咽癌CNE 2Z细胞增殖、凋亡的影响。方法 :用电转染的方法将带有绿色荧光蛋白GFP报道系统的端粒酶核酶基因的真核表达质粒PGFPuro teloRZ7 1及空载质粒PPAT GFP导入人低分化鼻咽癌CNE 2Z细胞 ;检测转染细胞的GFP表达情况、细胞增殖指数及凋亡。结果 :CNE 2ZGTR7 1细胞 (转染目的基因质粒PGFPuro teloRZ7 1的CNE 2Z细胞 )和CNE 2ZG细胞 (转染空载质粒PPAT GFP的CNE 2Z细胞 )有GFP表达 ,而未转染的CNE 2Z细胞无GFP表达。流式细胞仪检测显示 ,CNE 2ZGTR7 1细胞增殖指数 [(2 5 10 0±0 14 1) % ]明显低于CNE 2Z细胞 ,即未转染的细胞 [(5 3 663± 16 981) % ]和CNE 2ZG细胞 [(61 5 75± 5 166) % ] ,差异有统计学意义 ,P <0 0 1。CNE 2ZGTR7 1细胞传第 12代后有凋亡出现 ,CNE 2Z及CNE 2ZG细胞无凋亡。结论 :端粒酶核酶基因的导入使CNE 2Z细胞的增殖能力下降并可诱导CNE 2Z细胞凋亡。端粒酶RNA模板区可以作为鼻咽癌的一个治疗靶点 ,端粒酶RNA模板区特异性核酶可望成为有效的端粒酶抑制剂 ,在肿瘤反义核酸治疗的实验研究中发挥作用     

GFP报道基因在鼻咽癌细胞系CNE-2Z中的表达

目的　观察GFP报道基因在鼻咽癌细胞系CNE 2Z中的表达。方法　将带有GFP报道基因的载体质粒pPAT GFP和 3种带有GFP报道基因及目的基因抗端粒酶核酶基因teloRZ的不同质粒 pGFPuro teloRZ 2 .1、pGFPuro teloRZ 7.1、pGFPuro teloRZ 7.7,转染到鼻咽癌CNE 2Z细胞系中 ,用荧光显微镜及流式细胞仪检测转染细胞在固定后的活细胞中GFP基因的表达情况。结果　GFP基因在活细胞中有表达 ,而在固定后无表达 ,且目的基因的插入影响GFP基因的表达。结论　GFP基因在转染了含目的基因质粒的鼻咽癌CNE 2Z细胞中稳定表达 ,可以在CNE 2Z细胞株和抗端粒酶模板区核酶的研究中作为质粒转染和基因表达的报道基因     

质粒表达的短发夹状RNA特异性抑制鼻咽癌细胞的增殖

目的观察pmU6-sibclD重组体在细胞内表达的bcl-xL短发夹状RNA(short hairpin RNA,shRNA)能否特异地抑制人鼻咽癌CNE-2Z细胞的增殖.方法将自行构建的表达短发夹状RNA的重组质粒转染到人鼻咽癌CNE-2Z细胞株、卵巢癌HO-8910细胞株和正常人类肝脏L-O2细胞株中,流式细胞仪检测转染率,MTT比色法检测细胞的生长抑制率.结果bcl-xLshRNA能特异地抑制CNE-2Z细胞株的生长增殖,而对正常人类肝脏细胞株的生长增殖和HO-8910细胞中的绿色荧光蛋白(green fluorescence protein,GFP)的表达无抑制作用.结论pmU6-sibclD重组体在细胞内表达的短发夹状RNA能特异性抑制鼻咽癌细胞的生长增殖,为质粒介导的RNAi技术运用于肿瘤的基因治疗提供一定的理论依据.     

腺病毒介导的shRNA沉默hTERT基因表达对鼻咽癌细胞增殖和凋亡的影响

目的探讨靶向人端粒酶反转录酶（hTERT)的短发夹RNA（shRNA)对人鼻咽癌细胞株CNE-2 hTERT表达的影响,及其对鼻咽癌细胞增殖和凋亡的效应。方法构建表达绿色荧光蛋白(EGFP)基因和靶向hTERT基因短发夹RNA的重组腺病毒质粒,观察其对鼻咽癌细胞株(CNE-2)的转染效果,RT-PCR检测hTERT mRNA表达水平,Western blot检测hTERT蛋白表达水平,CCK-8法检测细胞增殖活性,流式细胞仪检测细胞凋亡状况。结果Adv-EGFP-shTERT重组腺病毒质粒转染率可达90%以上,成功转染CNE-2细胞24 h后,hTERT mRNA的表达水平显著下降,转染48 h后,hTERT蛋白表达明显下调,细胞增殖活性受到显著抑制,细胞凋亡率可达23.0%。结论腺病毒载体介导靶向hTERT基因的RNA干扰,能显著抑制端粒酶反转录酶表达,进而抑制端粒酶活性,抑制CNE-2细胞增殖并诱导其凋亡,为鼻咽癌的基因治疗研究提供了理论基础。     

lncRNA LAMA5-AS1通过上调TFPI2表达抑制鼻咽癌细胞的增殖和迁移

目的:检测鼻咽癌组织和细胞株中长链非编码RNA（long non-coding RNA，lncRNA）LAMA5-AS1的表达，观察lncRNA LAMA5-AS1对鼻咽癌细胞增殖和迁移的影响并探讨其作用机制。方法:荧光实时定量聚合酶链式反应（qPCR）分别检测lncRNA LAMA5-AS1在68例鼻咽癌组织及62例慢性鼻咽炎组织、鼻咽癌细胞株及永生化鼻咽上皮细胞中的相对表达。选择lncRNA LAMA5-AS1表达最少的细胞株，分别转染阴性对照质粒（对照组）或载有lncRNA LAMA5-AS1序列质粒（实验组）。MTS法和细胞划痕实验分别检测高表达lncRNA LAMA5-AS1对细胞增殖和迁移能力的影响。qPCR检测高表达lncRNA LAMA5-AS1对组织因子途径抑制物2（tissue factor pathway inhibitor 2，TFPI2）基因mRNA表达的影响，Western blotting检测TFPI2蛋白和ERK信号通路蛋白表达。结果:与慢性鼻咽炎组织比较，lncRNA LAMA5-AS1在鼻咽癌组织中表达明显降低（P＜0.01）。与人永生化鼻咽上皮细胞比较，lncRNA LAMA5-AS1在鼻咽癌细胞株中表达明显降低（P＜0.01），在CNE-2Z细胞中的表达最少（P＜0.01）。与对照组比较，实验组CNE-2Z细胞的增殖能力从第3天开始明显降低（P＜0.05），实验组CNE-2Z细胞迁移能力明显下降（P＜0.01）。与对照组比较，实验组CNE-2Z细胞中TFPI2在mRNA和蛋白水平的表达明显增加（P＜0.01），ERK信号通路蛋白p-ERK、MSK1、MNK和STAT3表达明显降低。结论:lncRNA LAMA5-AS1在鼻咽癌组织和细胞株中表达明显降低，高表达lncRNA LAMA5-AS1可通过上调TFPI2基因表达、下调ERK信号通路活性，抑制鼻咽癌CNE-2Z细胞的增殖和迁移能力。     

miR-145抑制c-Myc基因表达对鼻咽癌细胞增殖的影响

目的：探究miR-145影响鼻咽癌细胞增殖可能的机制。方法：采用Real-time PCR法检测鼻咽癌细胞株CNE-1、CNE-2、CNE-2Z和鼻咽部永生化上皮细胞株NP69中miR-145和c-Myc的mRNA表达水平,Western blotting法检测c-Myc的蛋白表达水平,双萤光素酶报告基因实验检测miR-145与基因c-Myc的关系。分别将miR-Negative control、miR-145 mimics和si-NC、si-c-Myc转染进入CNE-1细胞,采用Real-time PCR及Western blotting法检测转染效果,CCK-8法检测转染后细胞的增殖情况,以及碘化丙啶（IP）染色流式细胞术检测细胞周期情况。结果： miR-145在鼻咽癌细胞系中明显低表达。转染miR-145后明显抑制CNE-1细胞的增殖\[3 d: （1.03±0.02） vs （1.21 ± 0.02）, P<0.05\];\[ 4 d: （1.79±0.02） vs （2.09±0.07）, P<0.01\]和导致G1期阻滞\[（79.57±1.47）% vs （69.98±1.16）%,P<0.05\]。miR-145可以直接作用于c-Myc的3’UTR区域,抑制c-Myc的转录和表达。c-Myc下调可明显抑制CNE-1细胞的增殖\[3 d: （0.80±0.02） vs （1.02±0.01）, P<0.01\];\[4 d: （1.68±0.4） vs （1.92±0.07）, P<0.01\],并致G1期阻滞\[（63.73± 1.81）% vs （54.10±2.26）%,P<0.05\]。结论： miR-145通过靶向作用于c-Myc的3’UTR区来抑制鼻咽癌细胞的增殖,对更深入探索鼻咽癌的诊断和治疗有着重要意义。     

姜黄素诱导低分化鼻咽癌细胞株CNE-2Z的凋亡

背景与目的:鼻咽癌(nasopharyngealcarcinoma,NPC)是我国南方地区的高发肿瘤,发病早期的治疗主要是以放疗为主,而对晚期NPC患者则有必要进行适当的化疗。一些药物可通过诱导肿瘤细胞凋亡来达到治疗肿瘤的目的。本研究拟探讨姜黄素对人鼻咽癌细胞株CNE-2Z体外增殖抑制作用及凋亡的影响。方法:不同浓度姜黄素处理CNE-2Z细胞,用噻唑蓝(MTT)法测定增殖抑制率和IC50;用流式细胞术、Hoechest33258/碘化丙啶(PI)双染、琼脂糖电泳法观察细胞凋亡。结果:姜黄素能抑制CNE-2Z细胞的生长,其效果与姜黄素的浓度和作用时间有关,作用24h、48h、72h的IC50值为(24.05±0.47)、(19.20±0.17)、(7.35±0.50)μmol/L;5、10、20μmol/L姜黄素处理细胞24h后,流式细胞术观察到细胞凋亡率分别为(4.9±3.2)%、(10.7±2.7)%和(14.7±0.5)%;10、20μmol/L姜黄素处理细胞24h后,荧光染色可见细胞缩小,染色质固缩,核染色体碎裂等凋亡形态学改变,琼脂糖凝胶电泳可见DNA梯形条带。结论:姜黄素可诱导CNE-2Z细胞凋亡,姜黄素对CNE-2Z细胞具有增殖抑制作用。     

端粒酶锤头状核酶抑制肺癌细胞端粒酶活性及细胞增殖的实验研究

目的:探讨端粒酶特异性核酶对A549肺癌细胞端粒酶活性、增殖和凋亡的影响。方法:构建人端粒酶锤头状核酶真核表达质粒,稳定转染人A549肺癌细胞株。RT-PCR法检测核酶的表达以及hTERT mRNA、hTR的含量,TRAP法测定细胞端粒酶活性,MTT法、流式细胞仪等测定细胞增殖及凋亡。结果:稳定转染核酶重组体的细胞克隆,均可以检测到核酶的表达,端粒酶活性被抑制,clonehTERT1～6和clonehTR(1、3、5)的平均端粒酶活性分别是空白对照组的(27±18)%和(36±13)%,P值分别为0.000和0.013;clonehTERT1～6hTERT mRNA及clonehTR1～6hTR含量下降,分别是空白对照组的(30±19)%和(49±17)%,P值分别为0.000和0.001;clonehTERT1、clonehTR3生长较空白对照组及阴性对照组减缓,凋亡率增加;而clonehTERT1又较clonehTR3生长慢,凋亡率高(凋亡率分别为21.5%和16.1%)。结论:端粒酶特异性核酶能明显抑制端粒酶活性和细胞增殖,促进细胞凋亡;端粒酶hTERT mR-NA可能是比端粒酶RNA更为理想的端粒酶抑制剂的靶点。     

低氧诱导鼻咽癌细胞表达血管内皮生长因子

背景与目的:低氧是大多数实体瘤(包括鼻咽癌)肿瘤微环境中的一个普遍存在的现象。研究表明,低氧能诱导血管内皮生长因子(vascularendothelialgrowthfactor,VEGF)在神经胶质瘤(C6)等细胞中的表达。本实验研究低氧对VEGF在体外培养的鼻咽癌细胞株(CNE-2Z)表达的影响,并探讨其与肿瘤转移的关系。方法:建立CNE-2Z细胞体外低氧细胞培养模型。在低氧处理24h后,分别以RT-PCR和Westernblot方法检测VEGF基因在mRNA和蛋白质水平的表达变化。结果:RT-PCR证实CNE-2Z细胞表达VEGF189,VEGF165,VEGF145和VEGF121等4种VEGFmRNA同工型。此四种mRNA同工型在低氧处理24h后均表达增加,分别是常氧对照组的(2.67±0.30)、(2.05±0.03)、(2.73±0.15)和(1.65±0.01)倍。Westernblot显示,低氧实验组VEGF蛋白表达是常氧对照组的(2.20±0.07)倍。结论:CNE-2Z细胞表达VEGF基因。体外低氧处理能使CNE-2Z细胞中VEGF表达增加。     

核酶对食管癌EC9706细胞端粒酶活性及凋亡的影响

目的 :观察针对人端粒酶RNA模板区的核酶对食管癌细胞端粒酶活性和细胞凋亡的影响。方法 :利用脂质体Lipofectamine介导 ,将已构建好的带有端粒酶核酶基因的重组质粒pBBS2 12Rz及空载质粒pBBS2 12转染食管癌EC970 6细胞 ,采用TRAP ELISA法检测端粒酶活性 ,用倒置相差显微镜及流式细胞仪观察细胞生长和凋亡情况。结果 :重组质粒pBBS2 12Rz转染的食管癌EC970 6细胞的端粒酶活性明显下降 ,细胞生长速度明显变慢 ,凋亡加速。结论 :端粒酶核酶对食管癌细胞端粒酶活性和细胞生长有抑制作用 ,可望成为食管癌基因治疗的新方法     

Effects of RNA interference targeting four different genes on the growth and proliferation of nasopharyngeal carcinoma CNE-2Z cells

To explore the effects of RNA interference targeting four different genes (VEGF, C-myc, Survivin, hTERT) on the growth and proliferation of nasopharyngeal carcinoma (NPC) CNE-2Z cells. Fluorescein-labeled short-hairpin (sh)RNA plasmids together and separately targeting VEGF, C-myc, Survivin and hTERT were built and respectively called plasmid-shVEGF-shC-myc-shSurvivin-shhTERT, plasmid-shVEGF, plasmid-shC-myc, plasmid-shSurvivin, plasmid-shhTERT. These plasmids were respectively transfected into human NPC CNE-2Z cells and xenograft tumors in nude mice. The expression of plasmids in NPC CNE-2Z cells and xenograft tumors was observed. Cell proliferation was detected with MTT assay. The mRNA and protein expression were determined by real-time PCR and western blot, respectively. The effects of plasmids on the biological behavior of CNE-2Z cells were observed with transwell invision chamber models. Apoptosis was determined with flow cytometer. The inhibitory effect of plasmids on xenograft tumors was observed in nude mice. The plasmid containing four different shRNAs could significantly inhibit CNE-2Z cell proliferation and decrease invasion ability in vitro compared with plasmids with each single shRNA (P<0.05). The plasmid containing four different shRNAs could simultaneously downregulate VEGF, C-myc, surviving, hTERT mRNA and protein expression in the CNE-2Z cells. The multiple gene shRNA could more significantly induce cell apoptosis than each single shRNA, respectively (P<0.05). The combinative silencing of these four genes had a better inhibitory effect on xenograft tumors than the silencing of each single shRNA (P<0.05). RNA interference targeting multiple genes can effectively inhibit NPC proliferation and induce apoptosis, which provides an experiment basis for NPC gene therapy.     

Attenuation of telomerase activity by hammerhead ribozyme targeting human telomerase RNA induces growth retardation and apoptosis in human breast tumor cells

Ribozyme possesses specific endoribonuclease activity and catalyzes the hydrolysis of specific phosphodiester bonds, which results in the cleavage of target RNA sequences. Here, we evaluated the ability of hammerhead ribozymes targeting human telomerase RNA (hTR) to inhibit the catalytic activity of telomerase and the proliferation of cancer cells. Hammerhead ribozymes were designed against 7 NUX sequences located in open loops of the hTR secondary structure. We verified the ribozyme specificity by in vitro cleavage assay by using a synthetic RNA substrate. Subsequently, we introduced ribozyme expression vector into human breast tumor MCF-7 cells and assessed the biologic effects of ribozyme. Hammerhead ribozyme R1 targeting the template region of hTR efficiently cleaved hTR in vitro, and stable transfectants of this ribozyme induced the degradation of target hTR RNA and attenuated telomerase activity in MCF-7 cells. Moreover, the ribozyme R1 transfectant displayed a significant telomere shortening and a lower proliferation rate than parental cells. Clones with reduced proliferation capacity showed enlarged senescence-like shapes or highly differentiated dendritic morphologies of apoptosis. In conclusion, the inhibition of telomerase activity by hammerhead ribozyme targeting the template region of the hTR presents a promising strategy for inhibiting the growth of human breast cancer cells.     

转染抗VEGF发夹状核酶基因白血病细胞模型的建立

 目的 建立转染抗血管内皮生长因子（VEGF）发夹状核酶基因的白血病细胞模型,探讨发夹状核酶对白血病细胞系K562 VEGF基因表达的效应。方法 采用脂质体介导的方法将抗VEGF发夹状核酶基因真核表达载体（pcDNA3-RZ）转染入人白血病细胞系K562,G418抗性筛选获得阳性克隆,转染VEGF pcDNA3-RZ和空载体（pcDNA3）的细胞组均有抗性细胞生长,分别命名为K562-RZ和K562-PC;抽提基因组DNA,用PCR方法验证核酶基因已转染入K562细胞,荧光定量PCR和western blot方法分别检测白血病细胞VEGF mRNA和蛋白的表达量;同时测定K562-RZ,K562-PC和 K562三组培养上清刺激内皮细胞生长的情况。结果 抗VEGF pcDNA3-RZ成功转入白血病细胞系K562,G418筛选2周获得阳性克隆,PCR检测证实核酶基因整合入白血病细胞基因组DNA;与K562及K562-PC细胞相比,转染VEGF核酶基因的K562-RZ细胞VEGF mRNA和蛋白的表达量明显降低;K562-RZ组培养上清对内皮细胞的刺激作用明显弱于K562-PC组。结论 建立了转染VEGF发夹状核酶基因的白血病细胞模型,抗VEGF发夹状核酶基因可明显下调白血病细胞VEGF的表达,为抗肿瘤治疗提供了新的线索。     

Minicircle-IFNgamma induces antiproliferative and antitumoral effects in human nasopharyngeal carcinoma.

PURPOSE: The aims of this work were to investigate the antitumor effect of IFNgamma gene transfer on human nasopharyngeal carcinoma (NPC) and to assess the potential of minicircle vector for antitumor gene therapy. EXPERIMENTAL DESIGN: We developed a recombinant minicircle vector carrying the human IFNgamma gene and evaluated the effects of minicircle-mediated IFNgamma gene transfer on NPC cell lines in vitro and on xenografts in vivo. RESULTS: Relative to p2PhiC31-IFNgamma, minicircle-mediated IFNgamma gene transfer in vitro resulted in 19- to 102-fold greater IFNgamma expression levels in transfected cells (293, NIH 3T3, CNE-1, CNE-2, and C666-1) and inhibited the growth of CNE-1, CNE-2, and C666-1 cells more efficiently, reducing relative growth rates to 7.1 +/- 1.6%, 2.7 +/- 1.0%, and 6.1 +/- 1.6%, respectively. Flow cytometry and caspase-3 activity assays suggested that the antiproliferative effects of IFNgamma gene transfer on NPC cell lines could be attributed to G(0)-G(1) arrest and apoptosis. Minicircle-mediated intratumoral IFNgamma expression in vivo was 11 to 14 times higher than p2PhiC31-IFNgamma in CNE-2- and C666-1-xenografted mice and lasted for 21 days. Compared with p2PhiC31-IFNgamma treatment, minicircle-IFNgamma treatment significantly increased survival and achieved inhibition rates of 77.5% and 83%, respectively. CONCLUSIONS: Our data indicate that IFNgamma gene transfer exerts antiproliferative effects on NPC cells in vitro and leads to a profound antitumor effect in vivo. Minicircle-IFNgamma is more efficient than corresponding conventional plasmids due to its capability of mediating long-lasting high levels of IFNgamma gene expression. Therefore, minicircle-mediated IFNgamma gene transfer is a promising novel approach in the treatment of NPC.     

反义端粒酶RNA对人胃癌细胞端粒长度及端粒酶活性调控的研究

 目的　探讨反义端粒酶RNA(hTR)对人胃癌细胞 端粒长度(TRF)及端粒酶活性的调控作 用。方法　应用反义hTR真核表达载体经脂质体介导转染胃癌细胞SGC7901 ,通过分子杂交及端粒重复扩增PCR方法检测hTR表达及端粒、端粒酶活性变化。结 果　经HYR筛选,转染细胞形成稳定克隆,反义hTR表达增强、正义hTR表达下调,平 均TRF缩短、端粒酶活性受抑。结论　反义hTR对胃癌细胞TRF及端粒酶活性 的调控可能是通过其对hTR模板的“封闭”而发挥作用的,反义hTR可以作为胃癌基因治疗的 一种新靶点。     

Inhibition of telomerase RNA (hTR) in cervical cancer by adenovirus-delivered siRNA

Small interfering RNA (siRNA) has become a powerful tool for selectively silencing gene expression in cultured mammalian cells. In this study, a 67-bp oligonucleotide encoding human telomerase RNA (hTR) was introduced into pSIREN, a shuttle vector for construction of recombinant adenovirus. Then the U6-RNA promoter and siRNA-encoding insert were cut out from the pSIREN and subcloned into pAdeno-X to construct the plasmid pAd-hTR. After the pAd-hTR was transfected into a mammalian cell line HEK-293, adenovirus carrying the hTR-targeting siRNA (Ad-hTR-siRNA) was obtained. We performed a series of experiments to demonstrate silencing of the telomerase mediated by Ad-hTR-siRNA in HeLa cells. Compared with control virus (Ad-NT-siRNA), Ad-hTR-siRNA significantly reduced both hTR mRNA level (by 70.21%) and telomerase activity (by 58.87%) in HeLa cells. Moreover, it induced apoptosis in HeLa cells. Treatment of subcutaneous tumor xenografted with Ad-hTR-siRNA could slow down tumor growth, at least partially due to the induction of apoptosis (P<0.05) in vivo. Taken together, our results demonstrated efficient and specific knockdown of telomerase in HeLa cell line by the hTR siRNA, and indicated the prospect of applying this siRNA expressing recombinant adenovirus system in cancer gene therapy.