上皮性卵巢癌hTERT表达及端粒酶活性的研究

目的探讨人端粒酶反转录酶(hTERT)表达及端粒酶活性与卵巢癌发生、发展的关系,评价其可否作为卵巢癌的肿瘤标志物及预后指标.方法应用RT-PCR及端粒重复扩增方法对43例上皮性卵巢癌、11例良性卵巢肿瘤和卵巢正常组织以及4例交界性卵巢肿瘤共69份标本进行hTERTmRNA及端粒酶活性检测.结果hTERT表达及端粒酶活性率在卵巢癌中分别为83.7%(36/43)及76.7%(33/43),良性肿瘤中均为9%(1/11),在正常卵巢组织和交界性卵巢肿瘤中阴性,其差异在卵巢癌与良性肿瘤及正常组织间均有显著性(P值分别为0.0004及0.0001).hTERT及端粒酶阳性率在某些预后因素如肿瘤类型、组织学分级、临床分期及肿瘤转移之间的差异皆无显著性.结论卵巢癌中存在高频率的hTERT表达及端粒酶激活,表明hTERT作为端粒酶的催化亚基,在肿瘤细胞端粒酶的激活中起关键作用.hTERT表达及端粒酶活性可望作为有价值的肿瘤标志物而用于卵巢癌的早期诊断,但其预后价值尚有待于进一步研究.     

靶向Survivin基因siRNA对HeLa细胞放射敏感性的影响

目的:探讨si RNA抑制Survivin表达对宫颈癌HeLa细胞γ射线敏感性的影响。方法:设计并合成si RNA,构建si R-NA真核表达载体的。将测序正确的pSU-PER/Survivin载体转染HeLa细胞,应用RT-PCR和流式细胞仪检测HeLa细胞中Survivin基因在mRNA和蛋白表达水平的改变。流式细胞仪检测各组HeLa细胞的凋亡率差异。结果:成功构建了pSUPER/Survivin载体。转染pSUPER/Survivin的HeLa细胞其Survivin基因表达水平明显低于未转染及转染空载体pSUPER的HeLa细胞。γ射线照射后,转染pSUPER/Sur-vivin的HeLa细胞凋亡细胞率显著高于其他两种细胞。应用χ2检验比较3种细胞的早期凋亡细胞率:转染pSUPER/Survivin与未转染(χ2=14.88,P=0.00);转染pSU-PER/Survivin与转染空载体pSUPER(χ2=13.10,P=0.00);未转染与转染空载体pSUPER(χ2=0.082,P=1.00)。结论:在HeLa细胞中抑制Survivin基因的表达能够提高其对γ射线的敏感性,增加细胞凋亡。     

Increased telomerase activity and elevated hTERT mRNA expression during multistage carcinogenesis of squamous cell carcinoma of the lung

BACKGROUND: Telomerase activation is believed to play a critical role in the immortalization of cells and carcinogenesis. Telomerase activity is undetectable in normal somatic cells (except for those cells undergoing proliferation) but is expressed in the majority of human tumors including lung carcinoma. The expression of hTERT mRNA has been found to be correlated with telomerase activity. In the current study, the authors analyzed telomerase activity and hTERT mRNA expression in preinvasive bronchial lesions using biopsy specimens obtained by fluorescence bronchoscopy. METHODS: The authors studied 150 bronchial biopsy specimens obtained by fluorescence bronchoscopy. The intensity of telomerase activity was determined by the fluorescence-based telomeric repeat amplification protocol method in 74 bronchial biopsy specimens (22 normal bronchial epithelium or bronchitis cases, 15 squamous metaplasia cases, 23 dysplasia cases, and 14 squamous cell carcinoma cases), and the level of hTERT mRNA was analyzed in another 76 specimens (24 normal bronchial epithelium or bronchitis cases, 15 squamous metaplasia cases, 20 dysplasia cases, and 17 squamous cell carcinoma cases) by real-time polymerase chain reaction. RESULTS: The mean values (+/- the standard deviation [SD]) of telomerase activity in normal bronchial epithelium or bronchitis, squamous metaplasia, dysplasia, and squamous cell carcinoma cases were 6.2 +/- 7.5, 13.9 +/- 14.8, 18.5 +/- 20.8, and 54.5 +/- 22.3 U/microg protein, respectively. The upper limit of telomerase activity in normal bronchial epithelium or bronchitis was 21 U/microg protein (mean + 2SD). It is interesting to note that, 5 of 15 squamous metaplasia biopsies (33%), 8 of 23 dysplasia biopsies (35%), and all squamous cell carcinoma biopsies (100%) exhibited levels of telomerase activity that were > 21 U/microg protein. The mean levels of hTERT mRNA in normal bronchial epithelium or bronchitis, squamous metaplasia, dysplasia, and squamous cell carcinoma cases were 891 +/- 840, 1936 +/- 1704, 3019 +/- 2607, and 12965 +/- 18008 copies/microg total RNA, respectively. Telomerase activity and hTERT mRNA expression were found to increase in proportion to the severity of histologic change from normal bronchial epithelium or bronchitis to squamous cell carcinoma. CONCLUSIONS: These results suggest that an increase in telomerase activity and hTERT mRNA expression are features of the early stages of the development of squamous cell carcinoma of the lung, with strong telomerase activity and hTERT mRNA expression being prominent during the latter stages.     

人BRMS1干扰质粒的构建及其有效性的鉴定

目的:构建针对人BRMS1基因的RNA干扰表达载体并检测其有效性,为后续研究提供基础。方法:设计合成针对人BRMS1的特异性si RNA前体寡核苷酸,依次通过退火,连接,构建含前体si RNA的重组质粒pcDNA6.2-GW/EmGFP-BRMS1-si-RNA。经测序鉴定后,通过脂质体介导将其与pDsRed2-N1-BRMS1质粒(包含BRMS1红色荧光融合蛋白的载体)共转染人胚肾293细胞。分别用倒置荧光显微镜和流式细胞术观察转染细胞中红色荧光蛋白的强度,检测干扰效果。结果:确定了两对针对人BRMS1的si RNA片段。经测序鉴定,两种含前体si RNA的质粒均构建成功。共转染后,倒置荧光显微镜下观察可见,两种si R-NA均能明显降低细胞中BRMS1的表达;用流式细胞仪检测证实,si RNA1及si RNA2分别使BRMS1表达下降67.33%和76.67%,与阴性对照组比较差异有统计学意义,P<0.05。结论:成功构建了针对人BRMS1基因的si RNA表达质粒,为进一步利用RNA干扰技术研究BRMS1功能与作用机制奠定了基础。     

人端粒酶逆转录酶(hTERT)特异性siRNA对乳腺癌细胞hTERT水平及细胞生长影响的研究

背景与目的:在肿瘤细胞中端粒酶高水平的表达是肿瘤细胞永生化的重要因素。本研究利用人端粒酶逆转录酶(hTERT)的小干扰RNA(siRNA)特异性地抑制乳腺癌细胞的hTERT,通过研究该效应对细胞生长、凋亡和永生化相关基因的影响,来进一步阐述端粒酶在肿瘤细胞永生化可能的作用。方法:通过实时定量RT-PCR(Real-TimeRT-PCR)测定各乳腺癌细胞系中内源性hTERT的表达水平及测定RNA干扰对与细胞永生化相关基因的调节;通过脂质体转染法将hTERTsiRNA导入MCF7细胞;通过细胞生长曲线和流式细胞仪(FACS)评价该特异性的siRNA所诱导的hTERT水平下调对细胞生长和凋亡的影响。结果:所检测的乳腺癌细胞系中,hTERT均相对高表达。hTERTsiRNA可抑制MCF7中hTERT的水平,并在抑制后的第4天开始表现出显著的细胞生长抑制,并出现凋亡,以及多个细胞永生化相关的基因,如RAC1、PCYT2、FDFT1和ATP5G2,表达水平均下调50%以上。结论:hTERTsiRNA可特异性地抑制hTERTmRNA水平,从而抑制细胞生长,导致细胞凋亡,并下调多个细胞永生化基因。     

支气管肺泡灌洗液脱落细胞端粒酶hTERT基因表达的检测

背景与目的:肺癌患者中端粒酶活性常呈阳性,常规检测端粒酶活性的方法易发生假阳性,端粒酶hTERT基因表达水平可反映端粒酶活性高低。本研究采用相对定量PT-PCR法检测肺癌支气管肺泡灌洗液脱落细胞端粒酶hTERT的表达情况,为肺癌的早期诊断、鉴别诊断提供帮助。方法:采用纤维支气管镜收集了20例可疑肺肿瘤患者支气管肺泡灌洗液,对脱落细胞分别送病理检测和RT-PCR相对定量法检测端粒酶hTERT基因表达,并随访术后病理检测情况,同时检测10例非肺癌病人的支气管肺泡灌洗液标本作为对照。结果:20例可疑肺癌经术后病理检测证实有19例为不同类型的肺癌,1例为炎性假瘤。在19例肺癌的支气管肺泡灌洗液中16例检出不同程度的端粒酶hTERT基因表达,细胞病理检测仅发现11例,阳性率分别为84.2%和57.9%,两者有显著性差异(P<0.01)。10例非肺癌病人的支气管肺泡灌洗液中均无端粒酶hTERT基因表达。结论:采用RT-PCR方法检测支气管肺泡灌洗液中端粒酶hTERT基因表达,较细胞病理检测有更高的敏感性,有助于肺癌的早期诊断和鉴别诊断。     

EGFR在RNAi-hTERT抑制HeLa细胞增殖过程中的作用研究

目的探讨EGFR在靶向hTERT的RNA干扰抑制HeLa细胞增殖过程中的作用。方法以HeLa细胞为实验细胞,将实验分为6组:A组未处理;B组转染试剂;C组转染空载体;D组转染阴性siRNA;E组转染siRNA-hTERT;F组同时转染pcDNA3.1-EGFR和siRNA-hTERT。转染48 h后,应用Western Blot法检测各组HeLa细胞的hTERT与EG-FR蛋白表达水平,MTT法分析各组转染24、48、72和96 h后4个时间点的细胞增殖抑制率。结果转染48 h后的3个时间点,E组细胞增殖抑制率显著高于C、D和F组(P<0.01、0.01、0.01),同时伴有EGFR蛋白表达水平显著降低;而F组EGFR蛋白表达水平恢复,细胞增殖抑制率未见升高。结论靶向hTERT的RNA干扰抑制HeLa细胞增殖,可能依赖于EGFR蛋白水平的下调。     

siRNA抑制survivin基因周期的影响表达对HeLa细胞

目的设计靶向survivin基因的干涉片段,构建真核表达载体pSUPER／survivin并转染宫颈癌HeLa细胞,探讨siRNA抑制survivin表达对联合1射线宫颈癌HeLa细胞周期的影响。方法化学合成干涉引物,退火获得survivin基因的干涉片段,连入pSUPER载体并测序。将测序正确的pSUPER／survivin载体转染HeLa细胞株,RT—PCR法和流式细胞术检测HeLa细胞中survivin基因的表达,流式细胞术检测转染联合＇射线照射后各组细胞的细胞周期数据。结果本实验成功的构建了pSUPER／survivin载体。转染pSUPER／survivin的HeLa细胞其survivin基因表达水平明显低于未转染的HeLa细胞及转染空载体pSUPER的HeLa细胞。1射线照射后,转染pSUPER／survivin的HeLa细胞发生了S期细胞比例下降,及G2／M期阻滞。结论成功的构建了pSUPER／survivin载体,siRNA干涉survivin可以作为提高放射敏感性的潜在分子靶点,通过减少S期细胞比例,促进肿瘤细胞凋亡,通过增加G2／M期阻滞增加放射线的杀伤。     

siRNA targeting LMP1-induced apoptosis in EBV-positive lymphoma cells is associated with inhibition of telomerase activity and expression

Epstein-Barr Virus (EBV) is closely associated with B cell malignancies. However, whether EBV appears to be absolutely required for cell proliferation and survival in lymphoma cells is still unknown. In this study, small interfering RNA (siRNA) targeting LMP1 was employed to investigate the effect of LMP1 on cell proliferation in EBV-positive lymphoblastoid B-cell line. A plasmid stable encoding 21-nt small RNA specifically and efficiently interfering LMP1 was constructed, resulting in a substantial loss of LMP1 mRNA and a significantly decreased LMP1 protein expression. Our data demonstrated that cell proliferation was completely inhibited and apoptosis was induced after knockdown of LMP1 gene in lymphoblastoid B-cell line. Also, we found that suppression of LMP1 caused downregulation of telomerase protein expression and decreased telomerase activity in lymphoma cells. In EBV-negative NPC cell line, transfection of plasmid expressing LMP1 greatly enhanced telomerase protein expression. Our results suggested that siRNA targeting LMP1 can induce apoptosis in EBV-positive lymphoma cells and is associated with inhibition of telomerase activity and expression. siRNA-directed LMP1 silencing may be of the therapeutic value for preventing and treating those EBV-associated tumors.     

榄香烯对HeLa细胞端粒酶催化亚单位基因表达的作用

目的：探讨HeLa细胞凋亡过程中,人乳头瘤病毒18型E6（HPV18-E6）基因、p53基因、端粒酶催化亚单位（hTERT)基因表达的变化,为临床诊断、治疗宫颈癌提供新思路,方法：用流式细胞仪、电镜证实细胞凋亡;用PCR和RT-PCR方法研究HPV18-E6基因、p53基因、hTERT基因表达在细胞凋亡过程中的变化及相互关系。结果：在榄香烯作用下,HPV18-E6基因、p53基因表达没有变化,但hTERT基因表达受到抑制。结论：榄香烯诱导HeLa细胞凋亡过程中的变化及相互关系。结果：在榄香烯作用下,HPV18-E6基因、p53基因表达没有变化,但hTERT基因表达受到抑制。结论：榄香烯诱导HeLa细胞凋亡过程中,hTERT基因表达受到明显抑制,对于耐药性肿瘤,端粒酶活的抑制可能代表一种新的化疗策略。