细胞周期对人脑胶质瘤端粒酶活性的影响

目的：研究人脑胶质瘤中端酶活性在不同细胞周期中的表达情况，以探讨恶性肿瘤细胞周期变化对端粒酶活性的影响。方法：采用端粒重复序列扩增方案（TRAP）－银染法检测了82例脑胶组织标本，并应用流式细胞术（FCM）测定它们的S期细胞比例（SPF），结果：82例脑胶质瘤标本中，有端粒酶活性表达共33例，阳性率为40．2％，星形细胞瘤和间变性星形细胞瘤中，端粒酶活性的表达与SPF无明显相关性，多形性胶质母细胞瘤端粒酶活性检测阳性标本的SPF值明显高于阴性标本，统计学分析再者结果差异有显著性。结论：在细胞周期中端粒酶活性的改变受到多种生物学因素的调节，其中恶性肿瘤本身的增殖活性可能起着关键性的作用。     

SYBR Green实时定量端粒重复序列扩增法检测端粒酶活性

【摘要】目的 采用实时定量端粒重复序列扩增法( RQ- TRAP法)检测不同细胞端粒酶活性。方法 用RQ- TRAP和TRAP-ELISA两种方法同时检测12种细胞的端粒酶活性性,并比较两种方法的检测结果。结果 RQ-TRAP方法能准确特异地检测系列稀释的293T细胞蛋白提取液的端粒酶活性,灵敏度可达8个细胞,扩增效率为99%。阴性对照组则未检测到端粒酶活性。RQ-TRAP方法测得12个细胞系中端粒酶的活性与TRAP-ELISA方法结果有相关性(R2=0.7625)。结论 RQ-TRAP方法检测端粒酶可行,与TRAP-ELISA方法相比,RQ-TRAP方法具有成本低,减少时长和支持高通量等优点,是一种新的可快速可靠定量端粒酶活性的方法。      

宫颈组织标本中端粒酶活性检测及临床意义

目的 探讨端粒酶在宫颈组织中的活性表达及临床意义。方法 采用端粒重复序列扩增－酶标法（TRAP－ELISA）,测定了68例宫颈组织中端粒酶活性,其中宫颈癌37例（包括3例原位癌）,不典型增生16例,宫颈炎15例。同时检测了31例利片标本的端粒酶活性,其中宫颈癌17例,不典型增生10例,宫颈炎4例。结果 活检标本中,宫颈癌端粒酶阳性检出率为91.6％,不典型增生阳性率为25.0％,宫颈炎标本未检出明确的端粒酶活性。宫颈刮片组织中,有1例宫颈癌检出端粒酶活性,另有8例宫颈癌及2例不典型增生检测出微弱的端粒酶活性。结论 端粒酶活性的检测对了解宫颈癌的发生发展过程有一定意义,可用于宫颈癌的早期诊断。宫颈刮片组织端粒酶检测,也有一定的临床应用价值。     

肝癌穿刺标本中端粒酶检测的临床研究

目的检测肝癌穿刺活检中的端粒酶活性，探讨其在肝癌诊断中的临床意义。方法采用TRAP．ELISA技术检测34例肝活检标本中的端粒酶活性。结果肝癌中端粒酶阳性80％，且明显高于其他检测指标。结论显示端粒酶检测是一项敏感性较高的指标，阳性率明显高于其他检测结果，配合细胞学检查，可提高肿瘤的早期诊断率，并有可能成为肝癌的生物学指标。     

组织端粒酶活性和细胞调亡指数的测定在胃癌早期临床诊断的意义

目的：探讨胃癌组织中端粒酶活性和细胞凋亡指数与正常组织相比较在癌组织中的变化，及其在胃癌早期诊断和临床分期方面的意义。方法：采用端粒扩增法（TRAP）检测端粒酶活性，应用免疫组织化学方法及TUNEL法检测胃癌组织的细胞凋亡指数。结果：胃粘膜活检标本中胃癌组织端粒酶阳性率达88．1％相近，提示大部分胃癌组织端粒酶处于活化状态。此结果在胃癌的早期诊断中具有重要的意义。     

口腔鳞状细胞癌中端粒酶的活性检测

目的 测定口腔鳞状细胞癌组织中端粒酶的活性，了解端粒酶与口腔鳞状细胞癌之间的关系。方法 采用端粒酶PCR，ELISA法对55例口腔鳞癌与20例正常口腔粘膜，18例口腔鳞癌及其癌旁组织中的端粒酶活性进行测定。结果 口腔鳞状细胞癌中端粒酶的活性明显高于正常粘膜组，而自身对照组癌组织的端粒酶活性也明显高于癌旁组织。结论 端粒酶的活性检测可以作为一种有效的口腔恶性肿瘤标记物用于口腔恶性肿瘤的辅助诊断。     

人食管鳞癌端粒酶活性的临床研究

目的：探讨端粒酶活性与食管癌临床生物学行为关系及临床应用价值。方法：采用端粒重复扩增－酶免疫吸附法检测人食管鳞癌组织、癌旁组织及正常食粘膜上皮组织中端粒酶活性表达。结果：35例食管组织中端粒酶阳性者占86．6％（31／35），癌旁组织中阳性率为17．1％（6／35），正常食管组织端粒酶活性均为阴性。当癌侵及肌层及外侵后，其阳性表达率高于局限于粘膜及粘膜下层者（P＜0．01）。伴淋巴结转移标本中其阳性率高于无淋巴结转移者（P＜0．05）。端粒酶活性与肿瘤组织类型，分化程度等无明显相关（P＞0．05）。结论：端粒酶活性在人食鳞癌的发生、发展进程中发挥重要作用，端粒酶有可能成为食管癌诊断和判断预后的生要生物标志物和治疗新靶点。     

人脑肿瘤端粒酶活性表达及其临床意义

目的 研究人类脑肿瘤中端粒酶的表达情况，探讨端粒酶活性与恶性脑肿瘤发生和发展的关系。方法 采用TRAP－银染法检测37例脑肿瘤组织和4例正常脑组织中的端粒酶活性。结果 37例脑肿瘤组织标本中，16例有端粒酶活性的表达，阳性率为43．2％；4例正常脑组织中均未检测到端粒酶活性。结论 端粒酶活性的表达与脑肿瘤的恶性程度密切相关，有可能成为恶性脑肿瘤的一个重要标志物。     

胃癌患者外周血中端粒酶活性表达及其临床意义

目的 检测胃癌患外周血中癌细胞端粒酶活性，以探讨端粒酶活性的表达及其临床意义。方法 通过用PCR-TRAP-ELISA法检测52例胃癌患外周血端粒酶的活性，按照肿瘤大小、分化程度、浸润深度、淋巴结有无转移来分析端粒酶与胃癌的关系。结果 外周血中检测端粒酶活性阳性率为53．8％，低于相应的胃癌组织阳性率(81．3％)，胃癌患外周血中肿瘤细胞端粒酶相对活性的升高与患的淋巴结转移和肿瘤的分化程度呈正相关。结论 对患判断肿瘤是否转移复发，检测患外周血中端粒酶活性要优于检测肿瘤组织的端粒酶活性。     

端粒酶活性与宫颈癌演进的关系

目的：研究端粒酶表达及其活性与宫颈癌发生发展的关系。方法：应用端粒复复序列扩增－酶联免疫吸附法（TRAP－ELISA）对30例宫颈癌和15例宫颈上皮内肿瘤组织的端粒酶活性进行检测，以吸光度（A）值判断端粒酶活性，同时检测20例正常宫颈上皮的端粒酶活性作为对照。结果：宫颈癌、宫颈上皮内肿瘤和正常宫颈上皮组织中端粒酶表达的阳性率分别为93．3％、26．7％和0％，组间比较，差异有显著性（P＜0．01）。宫颈癌组织的端粒酶活性明显高于宫颈上皮内肿瘤（P＜0．01）。结论：端粒酶的表达及其活性的进行性增高与宫颈癌的发生发展密切相关。     

Down-regulation of telomerase activity by anticancer drugs in human ovarian cancer cells

Maintenance of telomere length is crucial for survival of cells. Telomerase, an enzyme that is responsible for elongation of shortened telomeres, is active in human germ cells as well as most tumor tissues and experimentally immortalized cells. In contrast, most mature somatic cells in human tissues express undetectable or low telomerase activity, implying the existence of a stringent and negative regulatory mechanism. In this study we report the effects of anticancer drugs on telomerase activity in human cancer cells. In assaying for telomerase activity, we basically followed the original TRAP assay system, but with some modifications. A down-regulation of telomerase activity was found when cells of a human ovarian cancer cell line, A2780, were treated with;cis-diamminedichloroplatinum(II) (CDDP; cisplatin). However, down-regulation of telomerase activity was not found in cells of a cisplatin-resistant cell line, A2780CP, treated with cisplatin. On the other hand, telomerase activity in both the cell lines A2780 and A2780CP was reduced when A2780 or A2780CP was treated with adriamycin, an anthracycline antibiotic having a broad spectrum of antineoplastic activity. The different effects on the telomerase activity of the two types of anticancer drugs may be due the distinct chemical functions of these drugs. The present results may indicate a positive relationship between anticancer effects and down-regulation of telomerase activity by anticancer drugs.     

Potent inhibition of telomerase by small-molecule pentacyclic acridines capable of interacting with G-quadruplexes

A novel pentacyclic acridine, 3,11-difluoro-6,8,13-trimethyl-8H-quino[4,3,2-kl]acridinium methosulfate (RHPS4), has been identified as a potent inhibitor of telomerase in the cell-free telomeric repeat amplification protocol (TRAP). Modeling and biophysical studies suggest that RHPS4 inhibits telomerase through stabilization of four-stranded G-quadruplex structures formed by single-stranded telomeric DNA. In contrast to G-quadruplex interactive telomerase inhibitors described previously, RHPS4 inhibited telomerase at submicromolar levels (50% inhibition in the TRAP assay at 0.33 +/- 0.13 microM). Moreover, RHPS4 exhibited a wide differential between this potent inhibition of telomerase and acute cellular cytotoxicity (mean IC(50) value of 7.02 microM in 4-day growth inhibition assay). RHPS4, when added to 21NT breast cancer cells at nonacute cytotoxic concentrations (200 nM) every 3 to 4 days, induced a marked cessation in cell growth after 15 days. Similar effects were observed using another cell line possessing relatively short telomeres, A431 human vulval carcinoma cells, but not in a human ovarian carcinoma cell line (SKOV-3) possessing relatively long telomeres. In 21NT cells, growth cessation was accompanied by an increase in cells in the G(2)/M phase of the cell cycle, a reduction in cellular telomerase activity, and a lower expression of the hTERT gene. These effects occurred in the absence of a detectable reduction in telomere length as measured by slot blotting. RHPS4 also induced a cessation of growth of GM847 cells that maintain telomeres by a nontelomerase alternative mechanism for lengthening telomeres (ALT) after 15 days. RHPS4 represents a promising G-quadruplex interactive small molecule that is a potent cell-free inhibitor of human telomerase and induces growth inhibitory effects in human tumor cell lines after prolonged (2-week) exposure to nonacute cytotoxic drug concentrations.     

紫杉醇体外诱导人胃癌细胞凋亡及对端粒酶活性的影响

目的　研究紫杉醇对人胃癌细胞诱导凋亡作用及端粒酶活性变化。方法　 0 .0 0 1～ 1μmol/L的紫杉醇处理SGC 790 1细胞后 ,用MTT法测定胃癌细胞的生长抑制率 ,通过形态学观察及流式细胞术检测细胞凋亡率 ,半定量TRAP -银染法测定端粒酶活性变化。结果　不同浓度的紫杉醇对胃癌细胞均有明显抑制作用 ,且呈时间依赖性及剂量依赖性 ,光镜及流式细胞术分析表明 ,0 .0 1μmol/L的紫杉醇处理后 2 4h ,细胞即出现明显的凋亡形态特征及凋亡峰 ,对端粒酶活性的同步检测结果显示 ,紫杉醇在诱导细胞凋亡的同时伴随端粒酶活性下调 ,且随紫杉醇浓度增大 ,抑制作用逐渐增强 ,2 4h酶活性即显著受抑制 ,72h变为阴性。结论　紫杉醇对胃癌细胞具有明显抑制作用 ,诱导细胞凋亡并抑制端粒酶活性可能是其发挥抗癌作用的机制之一 ,端粒酶可作为肿瘤化疗的敏感性指标。     

Folic acid conjugated and Ag-carrying organoclay nanoparticles and their response to L929 fibroblast and DLD-1 cancer cells

This work presents the synthesis and characterisation of intercalated nanocomposites (NCs) from dispersed water solution blends of octadecyl amine-montmorillonite (ODA-MMT) (NC-0), folic acid (FA) conjugated ODA-MMT (NC-1) and Ag-MMT clay as a stable silver carrying agent (NC-2). The composition, chemical/physical and morphology of NCs with in situ intercalating nanostructures were investigated. Effect of organoclay, FA and Ag-MMT on L929 fibroblast (control), human colon carcinoma (DLD-1) cell lines, and the cytotoxicity, apoptosis and necrosis degree were estimated via WST-1/hemocytometric, double staining (as a ribonuclease A enzyme based method) and fluorescence microscopy methods in a dose-dependent manner. The mentioned cell lines integrated with NCs resulted in remarkable change in both morphology and nuclei of DLD-1 and fibroblast cells by apoptosis analysis. The number of necrotic cells were remarkably increased, as the toxic effects of nanocomposite nanoparticles were applied to both cell lines. Finally, the molecular mechanism of anticancer action of functionalised organoclays was elucidated.     

银杏外种皮多糖对SGC-7901细胞p53基因的表达及端粒酶活性的影响

目的　研究银杏外种皮多糖对人胃癌SGC 790 1细胞 p5 3基因表达及端粒酶活性的影响。 方法　应用免疫组织化学ABC法检测 p5 3基因的表达 ;应用TRAP ELISA法检测端粒酶活性。结果　银杏外种皮多糖 (80～ 16 0mg·L-1,4 8h)能抑制人胃癌SGC 790 1细胞突变型 p5 3基因的表达及其端粒酶活性。结论　银杏外种皮多糖抑制SGC 790 1细胞增殖的作用机制可能与其下调突变型 p5 3基因的表达和对端粒酶活性的抑制作用有关     

肺癌组织及支气管冲洗液中肺癌细胞的端粒酶活性分析

目的：研究纤支镜下取得的活检肺癌组织、支气管冲洗液中肺癌细胞的端粒酶活性,探讨并在肺癌诊断中的意义。方法：应用银染－TRAP,检测了26例癌组织、4例良性肺疾病组织,相应30例支气管冲洗液中的端粒酶活性表达。结果：26例肺癌组织中,22例端粒酶表达阳性,阳性率为84．64％。26例肺癌患者支气管冲洗液中,12例端粒酶表达阳性,阳性率46．15％。结论：端粒酶可能成为肺癌早期诊断的重要标志物,可能成为肿瘤治疗方面的重大突破口。     

The effect of silymarin on telomerase activity in the human leukemia cell line K562

Telomerase has been proposed as a novel and potentially selective target in cancer therapy. Silymarin, which is a standardized mixture of flavonolignans from the medical plant Silybum marianum, has potent effects against various types of cancer cells, but its effect on telomerase activity in the human leukemia cell line K562 has not been investigated. The aim of this study was to examine the mechanism of silymarin-induced apoptosis in K562 cells, with particular emphasis on its effect on telomerase activity. The antiproliferation effect of silymarin on K562 cells was evaluated by the MTT assay. To measure apoptosis, Hoechst 33342 staining and flow cytometry were used. The telomerase activity was determined using the telomeric repeat amplification protocol (TRAP)-ELISA assay. The treatment of the K562 cells with silymarin resulted in a significant inhibition of cell growth and telomerase activity. Also, a positive correlation was found between telomerase inhibition and induction of apoptosis in silymarin-treated K562 cells. These results suggest a novel mechanism in the anticancer activity of silymarin in human leukemia K562 cells and may provide a basis for future development of anti-telomerase therapies.     

孕激素受体拮抗剂ZXH951对乳腺癌细胞生长抑制作用及对端粒酶活性的影响

目的　研究ZXH951在体外对乳腺癌细胞的生长抑制作用及对端粒酶活性的影响。方法　分别用细胞生长曲线、集落形成及竞争性配体与受体结合法,测定ZXH951的体外抗肿瘤作用及其与孕激素受体（PR）、雌激素受体(ER)结合活性;用流式细胞术及多聚酶链反应-端粒重复序列扩增法探讨ZXH951对人乳腺癌T47D细胞周期及端粒酶活性的影响。结果　ZXH951对ER和PR双阳性的乳腺癌细胞T47D体外增殖有较强的抑制作用,而对ER和PR双阴性的人乳腺癌细胞MDA-MB-231无明显抑制作用;ZXH951与PR有较强结合活性,而与ER无明显结合活性;可将T47D细胞阻滞在G1期,并对端粒酶活性有一定抑制作用。 结论　ZXH951是一个有发展前景的新型抗孕激素类化合物,在体外对乳腺癌细胞有较强的抑制作用,其作用机制可能与其通过PR介导的细胞增殖及对端粒酶活性抑制有关。     

榄香烯乳对结肠癌Lovo细胞端粒酶活性、细胞凋亡及细胞周期的影响

目的：探讨榄香烯乳对结肠癌Lovo细胞的作用机制。方法：采用不用浓度的榄香烯乳处理结肠癌Lovo细胞后，分别应用四唑蓝比色试验、端粒重复扩增－微孔板杂交法、琼脂糖凝胶电泳方法及流式细胞仪研究榄香烯乳对结肠癌细胞生长、端粒酶活性、凋亡及细胞周期的影响。结果：榄香烯乳对结肠癌Lovo细胞增殖具有较强的抑制作用，能够抑制端粒酶活性，诱导细胞凋亡，且这种作用呈浓度及时间依赖；且细胞阻滞于G0/G1期。结论：榄香烯乳抑制结肠癌Lovo细胞恶性增殖与抑制端粒酶活性、诱导凋亡及细胞周期阻滞有关。