Testicular expression of survivin and human telomerase reverse transcriptase(hTERT)associated with spermatogenic function in infertile patients

Aim： To characterize the coexpression of survivin, an inhibitor of apoptosis （IAF）, and human telomerase reverse transcriptase （hTERT） in human testes with varying spermatogenic function. Methods： Transcript levels of survivin mRNA and hTERT mRNA were determined in normal testes （n = 11） and testes with defective spermatogenesis （n = 28） using real-time reverse-transcription polymerase chain reaction （RT-PCR）. The histological work-up was performed according to a modified Johnsen score. Results： Expressions of both survivin and hTERT were highest at median levels of 96.8 and 709 in normal spermatogenesis and dropped to 53.3 and 534 in testes with postmeiotic spermatogenic arrest （n = 10）. In severe spermatogenic failure （n = 18）, survivin expression was lacking in most specimens （n = 16）, whereas at least low levels of testicular hTERT expression were largely detectable with a normalized expression of 73 in premeiotic spermatogenic arrest （n = 7） and 45 in patients with Sertoli cell-only syndrome （SCOS） （n = 3）. Both survivin and hTERT expressions increased with a progressing Johnsen score （P for trend = 0.001）. Conclusion： Although both survivin and hTERT are correlated with spermatogenic function, they show different expression patterns in testes of infertile patients. These findings substantiate results from studies in the rodent testis suggesting a predominant expression of survivin in meiotically dividing germ cells. （Asian J Andro12006 Jan; 8： 95-100）

Quantification of human telomerase RNA (hTR) and human telomerase reverse transcriptase (hTERT) mRNA in testicular tissue of infertile patients

Aim: To evaluate the quantitative detection of human telomerase RNA (hTR) and human telomerase reverse tran-scriptase (hTERT) mRNA as diagnostic parameters in the workup of testicular tissue specimens from patients presentingwith non-obstructive azoospermia. Methods: hTR and hTERT mRNA expression were quantified in 38 cryopre-served testicular tissue specimens by fluorescence real-time reverse transcription - polymerase chain reaction (RT-PCR)in a LightCycler(r). This was paralleled by conventional histological workup in all tissue specimens and additionalsemithin sectioning preparation in cases with maturation arrest (n = 12) and Sertoli-cell-only syndrome (n = 12). Re-sults; The average normalized hTERT expression (N_(hTERT)) was 131.9±48.0 copies (mean ± SD) in tissue speci-mens with full spermatogenesis, N_(hTERT) = 51.2 ±17.2 copies in those with maturation arrest and N_(hTERT) = 2.7 ± 2.4copies in those with Sertoli-cell-only syndrome (SCOS). The discriminant analysis showed that detection of N_(hTERT)(N_(hTR)) had a predictive value of 86.8% (55.3%) for correct classification in one of the three histological subgroups.Conclusion; Our results demonstrate that quantitative detection of hTERT mRNA expression in testicular tissue en-ables a molecular-diagnostic classification of gametogenesis. Quantitative detection of hTERT in testicular biopsies isthus well suited for supplementing the histopathological evaluation. (Asian J Androl 2001 Dec; 3: 263 - 270)

Neuroprotective effects of human telomerase reverse transcriptase on beta-amyloid fragment 25-35-treated human embryonic cortical neurons

BACKGROUND： Numerous current studies have suggested that human telomerase reverse transcriptase （hTERT） gene has neuroprotective effects and can inhibit apoptosis induced by various cytotoxic stresses; however, the mechanism of action remains unknown. OBJECTIVE： To evaluate the neuroprotective effects and possible mechanism of action of hTERT gene transfection in human embryonic cortical neurons treated with beta-amyloid fragment 25-35 （AI325-35）. DESIGN, TIME AND SETTING： The randomized, controlled and molecular biological studies were performed at the Department of Anatomy and Brain Research, Zhongshan School of Medicine, Sun Yat-sen University, China, from September 2005 to June 2008. MATERIALS： AdEasy-1 Expression System was gifted by Professor Guoquan Gao from Sun Yat-Sen University, China. Human cortical neurons were derived from 12-20 week old aborted fetuses, obtained from the Guangzhou Maternal and Child Health Hospital, China. Mouse anti-Odk5 and mouse anti-p16 monoclonal antibodies （Lab Vision, USA）, and mouse anti-hTERT monoclonal antibody （Epitomics, USA）, were used in this study. METHODS： （1） Recombinant adenovirus vectors, encoding hTERT （Ad-hTERT） and green fluorescent protein （Ad-GFP）, were constructed using the AdEasy-1 Expression System. Human embryonic cortical neurons in the Ad-hTERT group were transfected with Ad-hTERT for 1-21 days. Likewise, human embryonic cortical neurons in the Ad-GFP group were transfected with Ad-GFP for 1-21 days. Human embryonic cortical neurons in the control group were cultured as normal. （2） Human embryonic cortical neurons in the Ad-hTERT group were treated with 10 pmol/L Aβ25-35 for 24 hours. Normal human embryonic cortical neurons treated with 10 pmol/Lβ25.35 for 24 hours served as a model group. Human embryonic cortical neurons in the Ad-GFP and control groups were not treated with Aβ25-35. MAIN OUTCOME MEASURES： Expression of hTERT in human embryonic cortical neurons was evaluated by immunocytochemical staining and Western blot assay. Telomerase activity was measured using a PCR-based telomeric repeat amplification protocol （TRAP） ELISA kit. Neural activity in human embryonic cortical neurons was examined by MTT assay; apoptosis was measured using TUNEL assay; and Cdk5 and p16 protein expressions were measured by Western blot. RESULTS： Expression of hTERT protein was significantly increased and peaked at day 3 post-transfection in the Ad-hTERT group. No hTERT expression was detected in the Ad-GFP and control groups. Telomerase activity was significantly greater in the Ad-hTERT group compared with the Ad-GFP and control groups （P 〈 0.01）. Compared with the control group, cell activity was significantly decreased （P 〈 0.05）, and cell apoptotic rate, Cdk5 and p16 expression were significantly increased （P 〈 0.01） in the model group. Compared with the model group, cell activity was increased in the Ad-hTERT group, and peaked at day 3 post-transfection （P 〈 0.05）. Neuroprotective effects also peaked at day 3 post-transfection; and the apoptotic rate, Cdk5 and p16 expression significantly decreased （P 〈 0.01）. CONCLUSION： Expression of hTERT in human embryonic cortical neurons can relieve Aβ25-35-induced neuronal apoptosis. The possible mechanism by which hTERT produces these neuroprotective effects may be associated with inhibition of Cdk5 and p16 expression.

Inhibition of telomerase with human telomerase reverse transcriptase antisense increases the sensitivity of tumor necrosis factor-α-induced apoptosis in prostate cancer cells

Aim： To investigate the effect of inhibition of telomerase with human telomerase reverse transcriptase （hTERT） antisense on tumor necrosis factor-α （TNF-α-induced apoptosis in prostate cancer cells （PC3）. Methods： Antisense phosphorothioate oligodeoxynucleotide （AS PS-ODN） was synthesized and purified. Telomerase activity was measured using the telomeric repeat amplification protocol （TRAP） and polymerase chain reaction enzyme-linked immunoassay （PCR-ELISA）. hTERT mRNA was measured by reverse transcription PCR （RT-PCR） assay and gel-image system, hTERT protein was detected by immunochemistry and flow cytometry. Cell viability was detected by 3-（4, 5-dimethylthiazol-2-yl）-2,5-Diphenyltetrazolium （MTT） assay. Cell apoptosis was observed by morphological method and determined by flow cytometry. Results： The telomerase activity decreased with time after hTERT AS PS-ODN treatment. The levels of hTERT mRNA decreased with time after hTERT AS PS-ODN treatment, which appeared before the decline of the telomerase activity. The percentage of positive cells of hTERT protein declined with time after hTERT AS PS-ODN treatment, which appeared after the decline of hTERT mRNA. There was no difference in telomerase activity, hTERT mRNA and protein levels between hTERT sense phosphorothioate oligodeoxynucleotide （S PS-ODN） and the control group. The cell viability decreased with time after hTERT AS PS-ODN combined with TNF-α treatment. The percentage of apoptosis increased with time after hTERT AS PS-ODN combined with TNF-α treatment. There was no difference in cell viability and the percentage of apoptosis between hTERT S PS-ODN and the control group. Conclusion： hTERT AS PS-ODN can significantly inhibit telomerase activity by downregulating the hTERT mRNA and protein expression, and inhibition of telomerase with hTERT antisense can enhance TNF-α- induced apoptosis of PC3 cells.

Unique case of oligoastrocytoma with recurrence and grade progression:Exhibiting differential expression of high mobility group-A1 and human telomerase reverse transcriptase

Mixed gliomas, primarily oligoastrocytomas, account for about 5%-10% of all gliomas. Distinguishing oligoastrocytoma based on histological features alone has limitations in predicting the exact biological behavior, necessitating ancillary markers for greater specificity. In this case report, human telomerase reverse transcriptase(hT ERT) and high mobility group-A1(HMGA1); markers of proliferation and stemness, have been quantitatively analyzed in formalin-fixed paraffin-embedded tissue samples of a 34 years old patient with oligoastrocytoma. Customized florescence-based immunohistochemistry protocol with enhanced sensitivity and specificity is used in the study. The patient presented with a history of generalized seizures and his magnetic resonance imaging scans revealed infiltrative ill-defined mass lesion with calcified foci within the left frontal white matter, suggestive of glioma. He was surgically treated at our center for four consecutive clinical events. Histopathologically, the tumor was identified as oligoastrocytoma-grade Ⅱ followed by two recurrence events and final progression to grade Ⅲ. Overall survival of the patient without adjuvant therapy was more than 9 years. Glial fibrillary acidic protein, p53, Ki-67, nuclear atypia index, pre-operative neutrophillymphocyte ratio, are the other parameters assessed. Findings suggest that hT ERT and HMGA1 are linked to tumor recurrence and progression. Established markers can assist in defining precise histopathological grade in conjuction with conventional markers in clinical setup.

子痫前期孕妇血清hTERT和Sirt6水平表达与疾病严重程度及妊娠结局评估中的价值研究

目的检测子痫前期孕妇血清中人端粒酶反转录酶(human telomerase reverse transcriptase,hTERT)、沉默信息调节因子6(silent information regulator 6,Sirt6)表达,并探究hTERT,Sirt6水平表达与疾病严重程度及妊娠结局评估中的价值。方法选取2018年1月~2022年12月在陕西省人民医院进行诊治的300例子痫前期孕妇作为子痫前期组,孕妇均符合《妊娠期高血压疾病诊治指南(2015)》中子痫前期诊断标准,选取同时期孕检的300例健康孕妇为对照组,根据病情严重程度将子痫前期组分为轻症子痫前期组(n=180)和重症子痫前期组(n=120),根据是否发生不良妊娠结局将子痫前期组分为正常妊娠组(n=165)和不良妊娠组(n=135)。酶联免疫吸附实验(enzyme-linked immunosorbnent assay,ELISA)法检测血清中hTERT和Sirt6水平,Spearman相关性分析血清中hTERT和Sirt6水平与子痫前期孕妇病情严重程度的相关性,利用受试者工作特征(receiver operating characteristic,ROC)曲线评估血清hTERT和Sirt6水平在子痫前期诊断及妊娠结局预测中的价值。结果与对照组比较,子痫前期组血清hTERT(22.15±5.82 ng/ml vs 30.12±9.56 ng/ml),Sirt6(5.26±1.62 ng/ml vs 7.06±2.29 ng/ml)水平降低,差异具有统计学意义(t=12.334,11.114,均P<0.001)。与轻症子痫前期组比较,重症子痫前期组孕妇血清hTERT(18.28±4.11 ng/ml vs 24.73±6.96 ng/ml),Sirt6(4.03±1.17 ng/ml vs 6.08±1.92 ng/ml)水平降低,差异具有统计学意义(t=9.142,10.469,均P<0.001)。与正常妊娠组比较,不良妊娠组子痫前期孕妇血清中hTERT(17.75±4.61 ng/ml vs 25.75±6.81 ng/ml),Sirt6(4.06±0.96 ng/ml vs 6.24±2.16 ng/ml)水平降低,差异具有统计学意义(t=11.639,10.878,均P<0.001)。Spearman相关性分析显示,血清hTERT,Sirt6水平与子痫前期孕妇疾病严重程度均呈负相关(r=-0.562,-0.604,均P<0.001)。ROC曲线分析结果显示,血清hTERT,Sirt6诊断子痫前期的曲线下面积(95%置信区间)[AUC(95%CI)]分别为0.711(0.673~0.747),0.727(0.689~0.762),两者联合诊断子痫前期的AUC(95%CI)为0.788(0.753~0.820),高于两者单独诊断(Z=2.719,2.154,P=0.007,0.031);血清hTERT,Sirt6预测子痫前期不良妊娠结局的AUC(95%CI)分别为0.786(0.735~0.831),0.783(0.732~0.829),两者联合预测子痫前期不良妊娠结局的AUC(95%CI)为0.849(0.804~0.888),高于两者单独预测(Z=1.855,1.861,P=0.032,0.031)。结论hTERT和Sirt6在子痫前期孕妇血清中水平较低,与子痫前期孕妇疾病严重程度均呈负相关,并对妊娠结局具有一定的评估价值。

Expression of Telomerase Reverse Transcriptase during the Malignant Transformation of Cadmium-Induced Cells

The objective of the present study was to investigate human telomerase reverse transcriptase (hTERT) mRNA and protein expressions during the cadmium chloride-induced malignant transformation of human bronchial epithelial (16HBE) cells. Fluorescence quantitative PCR (FQ-PCR) and Western blot analyses were performed to detect the hTERT mRNA and protein expressions in normal 16HBE cells, cadmium chloride-transformed 16HBE cells, and tumorigenic cells from nude mice inoculated with cadmium chloride-transformed 16HBE cells. Under the inner standard of GAPDH, the hTERT mRNA expression was significantly higher at different stages of malignant transformation (cadmium chloride-transformed 16HBE cells at passages 15 and 35 and tumorigenic cells from nude mice) than in normal 16HBE cells, and increased with the development of malignancy (P < 0.01). In addition, hTERT protein expression increased with the development of malignancy. These findings demonstrate that hTERT expression is related to cadmium chlorideinduced malignant transformation. Cadmium chloride-induced malignant transformation is involved in changes in the hTERT activity, and might be an early event in cadmium chloride-induced malignant transformation.

基于外周血hTERT、UCA1表达的列线图模型对老年膀胱尿路上皮癌术后无病生存的预测价值

目的:探讨基于围术期数据及外周血人端粒酶反转录酶(hTERT)、尿路上皮癌抗原1(UCA1)表达的列线图模型对老年膀胱尿路上皮癌术后无病生存的预测价值。方法:选取2017年4月至2019年4月首都医科大学附属北京友谊医院收治的268例老年膀胱尿路上皮癌患者,均行根治性膀胱切除术,随机分为建模人群和验证人群,根据术后3年无病生存率分为死亡组和存活组,比较两组一般资料和围术期数据。采用实时荧光定量PCR(RT-qPCR)法检测外周血hTERT、UCA1基因表达。采用Lasso、Cox回归方程分析老年膀胱尿路上皮癌术后无病生存的影响因素,构建列线图模型,绘制受试者工作特征曲线(ROC)、校准曲线及决策曲线分析预测性能。结果:患者术后3年无病生存率为55.77%。外周血hTERT、UCA1表达,输尿管切缘、年龄、肿瘤分期和淋巴结转移均为老年膀胱尿路上皮癌术后无病生存的影响因素(均P<0.05),基于上述因素构建的列线图模型在建模人群和验证人群中C-index分别为0.857、0.949,经校准曲线分析,0.2~1.0、0.1~1.0范围内该模型在建模人群和验证人群中预测净获益值较高。结论:外周血hTERT、UCA1高表达为老年膀胱尿路上皮癌患者术后无病生存的危险因素,所构建模型对患者术后无病生存状况有一定的预测价值。

Inhibitory Effects of Selenium on Telomerase Activity and hTERT Expression in Cadmium-transformed 16HBE Cells

To investigate the effects of sodium selenite on telomerase activity and expression of hTERT mRNA in cadmium-transformed 16HBE cells. Methods Telomerase activity and expression of genes were measured after cultured cadmium-transformed 16HBE cells were exposed to sodium selenite at different doses （0.625, 1.25, 2.50, 5.00 pmol/L） for 24 hours. Results Selenium decreased telomerase activity in cadmium-transformed 16HBE cells. There existed an obvious dose-effect relationship between the selenium concentration and these changes. The expression of hTERT and c-myc mRNA also decreased but the expression of madl mRNA increased after exposure to selenium for 24 hours. No difference was found in expression of hTRF1 and hTRF2 mRNA after incubated with sodium selenite for 24 hours, compared with control group. Conclusion Selenium inhibits telomerase activity by decreasing hTERT and c-myc mRNA expression and increasing madl mRNA expression in cadmium-transformed 16HBE cells and selenium concentration is significantly correlated with these changes.

Antitumor activity of an hTERT promoter-regulated tumor-selective oncolytic adenovirus in human hepatocellular carcinoma

AIM: To construct a tumor-selective replication-competent adenovirus (RCAd), SG300, using a modified promoter of human telomerase reverse transcriptase (hTERT). METHODS: The antitumor efficacy of SG300 in hepatocellular carcinoma was assessed in vitro and in vivo. In vitro cell viability by MTT assay was used to assess the tumor-selective oncolysis and safety features of SG300, and in vivo antitumor activity of SG300 was assessed in established hepatocellular carcinoma models in nude mice. RESULTS: SG300 could lyse hepatocellular carcinoma cells at a low multiplicity of infection (MOI), but could not affect growth of normal cells even at a high MOI. Both in Hep3B and SMMC-7721 xenograft models of hepatocellular carcinoma, SG300 had an obvious antitumor effect, resulting in a decrease in tumor volume. Its selective oncolysis to tumor cells and safety to normal cells was also superior to that of ONYX-015. Pathological examination of tumor specimens showed that SG300 replicated selectively in cancer cells and resulted in apoptosis and necrosis of cancer cells. CONCLUSION: hTERT promoter-regulated replicativeadenovirus SG300 has a better cancer-selective replication-competent ability, and can specifically kill a wide range of cancer cells with positive telomerase activity, and thus has better potential for targeting therapy of hepatocellular carcinoma.

Telomerase and hTERT: Can they serve as markers for gastric cancer diagnosis?

AIM:To investigate telomerase activity and human telomerase reverse transcriptase(hTERT)expression in normal human gastric mucosal epithelial cells(nhGMECs)and fibroblasts(nhGMFs).METHODS:nhGMECs and nhGMFs were isolated and cultured from specimens obtained during routine surgery for bleeding peptic ulcer.Telomerase activity in nhGMFs,nhGMECs,and the tumor cell lines BGC-823,SGC-7901 and MKN-28 cells was analyzed using the telomeric repeat amplification protocol assay.hTERT protein was determined in nhGMECs,nhGMFs,BGC-823,SGC-7901 and MKN-28 cells by indirect immunofluorescence.served in nhGMECs,nhGMFs and BGC-823,SGC-7901,MKN-28 cell lines.Positive hTERT immunostaining was detected in nhGMECs,nhGMFs,BGC-823,SGC-7901and MKN-28 cell lines.CONCLUSION:The use of telomerase or hTERT as diagnostic markers for gastric cancer may require further studies.

EXPRESSION OF A MUTANT hTERT IN HUMAN BLADDER CARCINOMA CELL LINE T24 AND ITS CLINICAL SIGNIFICANCE

To construct a mutant pEGFP- hTERTexpression vector, to observe its steady expression intransfected human bladder carcinoma cell line T24 and its role in molecular regulatory mechanisms of telomerase, and to provide a new target gene for bladder cancer. Methods: PCR amplification was performed by using primers basedon the known gene sequence of hTERT. PCR productionwas cloned into plasmid pGEMT-T easy and the sequenceof mutant hTERT gene was analyzed. A recombinantmutant hTERT vector (pEGFP-hTERT) was constructed at the EcoR I and Sal I sites of the pEGFP-C1 vector. Aftertransfecting the fusion gene into bladder carcinoma cell line T24 by calcium phosphate-DNA coprecipitation, the steady expression of GFP-hTERT fusion protein was tested by fluorescent light microscopy. The proliferation changes ofbladder carcinoma cell line T24 were detected by lightmicroscopy and senescence correlated b-galactosidase staining. Results: Identification of pEGFP-hTERT byenzyme digestion showed that mutant hTERT fragment had been cloned into EcoR I and Sal I sites of the pEGFP-C1 vector. The steady expression of GFP-hTERT fusion protein was localized in the nucleus of transfected cells. Expression of senescence-associated b-galactosidase in transfected cells gradually increased with extended cultured time and cellgrowth was suppressed. Conclusion: The mutant-type hTERT gene suppresses the proliferation of bladder carcinoma cell line T24 by competitive effect on telomerase activity. This suggests that hTERT gene might be a suitable gene target for bladder cancer therapy.

Inhibition of Cell Growth and Telomerase Activity in Osteosarcoma Cells by DN-hTERT

In order to study the effects of dominant negative human telomerase reverse transcriptase （DN-hTERT） on cell growth and telomerase activity in osteosarcoma cell line MG63, MG63 cells were transfected with DN-hTERT-IRES2-EGFP9 （DN） or IRES2-EGF （I, blank vector） with lipofectamine 2000. The stably transfected cells were selected with G-418. Cell growth properties were examined under a fluorescence microscope. The hTERT mRNA expression was detected by reverse transcription-polymerase chain reaction （RT-PCR）. Telomerase activities were measured by TRAP-ELISE. The tumorigenicity was studied with tumor xenografts by subcutaneous injection of cancer cells into nude mice. The results showed that cell growth was suppressed in MG63 cells transfected with DN-hTERT. The hTERT mRNA was increased in N-hTERT transfected-MG63 cells （MG63/DN）. The telomerase activity was 2.45±0.11 in MG63/DN cells, while 3.40±0.12 in the cells transfected with blank vector （MG63/I）, （P〈0.05）; DN-hTERT-expressing clones did not form tumors in 2 weeks, but the ratio of tumorigenesis was 30 % in nude mice bearing MG63/I （P〈0.01）. It was concluded that DN-hTERT could specifically inhibit the cell growth and telomerase activity in MG63 cells.

肝衰竭患者外周血单个核细胞hTERT mRNA及血清Ang-2和ICAM-1水平临床意义探讨

目的初步探讨肝衰竭患者外周血单个核细胞人瑞粒酶逆转录酶(hTERT)mRNA及血清血管生成素-2(Ang-2)和细胞间黏附分子-1(ICAM-1)水平变化的临床意义。方法2019年1月~2021年5月我院诊治的74例肝衰竭患者【亚急性肝衰竭(SALF)13例,慢加急性肝衰竭(ACLF)39例和慢性肝衰竭(CLF)22例】和同期健康体检者30例,分离并检测外周血单个核细胞(PBMC)hTERT mRNA水平,采用ELISA法检测血清Ang-2和ICAM-1水平。结果肝衰竭组PBMC hTERT mRNA、血清Ang-2和ICAM-1水平分别为(0.9±0.3)、(1344.6±55.3)ng/L和(540.2±22.4)ng/ml,显著高于健康人组【分别为(0.4±0.1)、(1062.5±36.2)ng/L和(167.3±15.6)ng/ml,P<0.05】;SALF患者PBMC hTERT mRNA、血清Ang-2和ICAM-1水平分别为(1.5±0.6)、(1507.8±38.2)ng/L和(647.3±26.2)ng/ml,显著高于ACLF患者【分别为(1.2±0.4)、(1398.6±35.8)ng/L和(582.7±24.1)ng/ml,P<0.05】或CLF患者【分别为(0.7±0.2)、(1280.5±46.3)ng/L和(468.9±20.3)ng/m,P<0.05】;经过1~3 m治疗,SALF组死亡3例,ACLF组死亡5例,CLF组死亡4例。结论肝衰竭患者PBMCs hTERT mRNA及血清Ang-2和ICAM-1水平显著升高,它们可能为判断肝损伤程度提供客观依据,值得进一步研究。

c-myc调节人端粒酶逆转录酶(htert)启动子活性的体外研究

目的 :研究c myc对人端粒酶逆转录酶 (htert)启动子的调节作用。方法 :采用Lipofect脂质体转染法将DNA质粒分别转染至肝癌细胞HepG2 、猴肾COS 7细胞和NIH3T3细胞 ,孵育 48h后 ,分别检测其报告基因萤虫素酶活性。结果 :与对照相比 ,载有htert 80 0bp启动子的质粒TERTLuc(80 0 )在肿瘤细胞HepG2 中活性显著增强。外源性转录因子c myc可显著上调htert启动子的表达 ,其激活作用与剂量呈正相关。人工突变c myc结合位点明显降低htert启动子的活性。结论 :c myc可直接激活htert启动子的表达 ,是调节端粒酶活性的重要转录因子。

三氧化二砷对HL-60细胞凋亡及其端粒酶hTERT-mRNA表达影响的实验研究

目的 探讨不同浓度的三氧化二砷 (As2 O3)对急性早幼粒细胞白血病细胞株HL 60细胞端粒酶亚单位hTERT mRNA表达及其诱导凋亡的作用。方法 不同浓度的As2 O3与HL 60细胞株共培养 48h ,流式细胞术鉴定HL 60细胞凋亡 ;RT PCR法检测HL 60细胞端粒酶亚单位hTERTmRNA的表达。结果 在 0 1、1 0和 5 0 μmol·L-13种浓度的As2 O3作用下 ,HL 60细胞凋亡率分别为 2 2 8%± 0 40 %、2 5 5 %± 0 2 2 %和 47 5 7%± 2 79% ;端粒酶亚单位hTERT mRNA表达的相对值分别为 73 97%、63 70 %和 2 9 0 4%。细胞凋亡率在 5 0 μmol·L-1与 0 1和 1 0μmol·L-1浓度组间差异有显著性 (P <0 0 1) ;端粒酶亚单位表达的差异也有显著性 (P <0 0 5 )。As2 O3诱导HL 60细胞凋亡效应与其抑制端粒酶亚单位hTERTmRNA的表达相关。结论 As2 O3对HL 60细胞具有凋亡诱导效应 ,且对其端粒酶亚单位hTERTmRNA的表达具有抑制作用 ,两者均呈现浓度依赖效应。As2 O3可能通过抑制HL

逆转录病毒介导反义hTERT对肺癌细胞的抑制作用

背景与目的:抑制端粒酶活性可以抑制细胞端粒延长,进而抑制永生细胞的增殖。为了探讨以端粒酶为靶的肺癌基因治疗可能性,本实验观察反义人端粒酶逆转录酶组分(humantelomerasereversetranscriptase,hTERT)cDNA对A549肺癌细胞的端粒酶活性和细胞增殖的抑制作用。方法:RT-PCR扩增hTERTmRNA5'起始端835bp的cDNA,分别正向和反向插入到逆转录病毒表达载体pLXSN质粒中,转染包装细胞PT67后获得重组病毒,病毒感染肺癌A549细胞。Westernblot检测hTERT蛋白表达,TRAP法检测端粒酶活性,倒置显微镜观察细胞形态变化和绘制细胞生长曲线了解细胞增殖情况,流式细胞仪和DNA片段电泳观察凋亡情况。结果:反义hTERT作用肺癌A549细胞后hTERT蛋白表达下降,端粒酶活性被抑制,细胞增殖受到抑制并出现明显的细胞凋亡。结论:反义hTERT对肺癌细胞A549端粒酶活性具有明显的抑制作用,抑制细胞生长,促进细胞凋亡,hTERT有可能成为肺癌基因治疗靶点。

3种卵巢癌细胞中hTERT转录水平及其与端粒酶活性的相关性研究

背景与目的:端粒酶在约90%的肿瘤细胞中有活性而在绝大多数正常细胞中受抑,催化亚单位端粒酶逆转录酶(humantelomerasereversetranscriptase,hTERT)是端粒酶的重要组成部分,其表达的调控主要发生在转录水平。端粒酶、hTERT、hTERT启动子三者之间密切相关。本研究探讨卵巢癌细胞系中hTERT启动子的活性及其与hTERTmRNA表达和端粒酶活性之间的关系。方法:应用脂质体转染法将hTERT核心启动子基因转入3种卵巢癌细胞OVCAR3、SKOV3、3AO及正常卵巢上皮细胞中,并用荧光素酶检测实验检测其中hTERT启动子的活性;应用RT-PCR半定量法检测这4种细胞中hTERTmRNA的表达水平;应用PCR-ELISA定量检测这4种细胞中端粒酶的活性。同时以端粒酶阳性的永生化人胚肾成纤维细胞HEK293作为阳性对照,以端粒酶阴性的人胚肺成纤维细胞HELF作为阴性对照。结果:OVCAR3、SKOV3、3AO细胞及正常卵巢上皮细胞中的hTERT启动子活性(视每种细胞中pGL3-control的启动子活性为100%)分别为31.4%、20.3%、17.7%和0.3%;hTERTmRNA的相对表达水平(视SKOV3的表达水平为1.00)分别为1.30、1.00、0.63和0;端粒酶活性分别为0.580、0.414、0.386和0.103(>0.200时定为阳性)。3种卵巢癌细胞中hTERT启动子活性、hTERTmRNA表达水平和端粒酶活性均特异性增高。

胶质瘤中hTERT、maspin和bFGF表达的相关性及意义

背景与目的:人端粒酶逆转录酶(human telomerase reverse transcriptase,hTERT)是端粒酶激活的决定因子,与肿瘤的形成和恶性程度有关,其表达受多种因素的调控。本研究检测胶质瘤中hTERT、maspin和碱性成纤维细胞生长因子(basic fibroblast growth factor,bFGF)蛋白的表达,并分析它们的相关性及其与临床病理因素之间的关系。方法:应用原位杂交法、免疫组织化学SP法分别检测128例胶质瘤和8例正常脑组织中hTERT及maspin、bFGF蛋白的表达;检测结果的半定量评定参照Gatalica的H-score(H=I×P)系统;两组间率的比较用χ2检验;不同级别胶质瘤中hTERT、maspin和bFGF的表达采用Spearman等级相关分析;hTERT与maspin和bFGF表达之间的关系采用直线相关分析。结果:(1)胶质瘤中hTERT、maspin、bFGF阳性率分别为51.6%(66/128)、46.9%(60/128)、62.5%(80/128)。8例正常脑组织均不表达hTERT、bFGF,7例表达maspin。Ⅱ、Ⅲ、Ⅳ级胶质瘤中,hTERT阳性率分别为32.6%(14/43)、54.5%(30/55)、73.3%(22/30);maspin阳性率分别为58.1%(25/43)、49.1%(27/55)、26.7%(8/30);bFGF阳性率分别为39.5%(17/43)、72.7%(40/55)、76.7%(23/30)。hTERT、maspin和bFGF在正常脑组织和不同级别胶质瘤中的表达差异均有显著性(P﹤0.05),hTERT和bFGF表达与病理分级呈正相关(ρ=0.515,P﹤0.01;ρ=0.611,P﹤0.01),maspin表达与病理分级呈负相关(ρ=-0.425,P﹤0.05)。(2)hTERT表达与maspin蛋白表达呈负相关(r=-0.658,P<0.01),与bFGF蛋白表达呈正相关(r=0.627,P<0.01);maspin和bFGF蛋白表达呈负相关(r=-0.501,P<0.01)。(3)hTERT表达与年龄、性别、肿瘤直径和细胞密度无关(P>0.05),与核分裂相、血管密度、坏死显著相关(P<0.05)。结论:hTERT、maspin和bFGF三者间的表达有相关性,均与胶质瘤恶性程度有关。