利用 RNAi阻抑 hTERT 和Bi-1双基因表达的RNAi作用效果的研究

目的：利用LipofectamineTM2000将针对靶向人类端粒酶末端逆转录酶（hTERT）和Bax inhibitor‐1（Bi‐1）基因设计并构建的质粒载体转染至CNE‐2Z鼻咽癌细胞内,诱导序列特异性的基因沉默,研究其产生的shRNA阻抑hTERT 和Bi‐1基因表达的效果。方法收集CNE‐2Z细胞,设未处理组、pEGFP‐N1组、pEGFP‐N1／Lip组,采用流式细胞术检测Lip对CNE‐2Z细胞的转染能力,RT‐PCR和Western blot法分析表达shRNA重组质粒载体对hTERT和Bi‐1基因mRNA表达的抑制效应。结果转染CNE‐2Z细胞的质粒和Lip最佳组合：质粒为2．5μg ,Lip为6．25μL。结论成功构建的针对人hTERT和Bi‐1基因的shRNA真核表达质粒能特异、有效地阻抑hTERT和Bi‐1基因的表达。     

Chlamydia trachomatis inhibits telomeric DNA damage signaling via transient hTERT upregulation

Epidemiological data exist to support a positive association between Chlamydia trachomatis (Ctr) infection and gynecological cancers; however, putative cellular mechanisms for this association are lacking. Here, we identified Ctr-induced perturbations to host cell phenotypes in vitro that persisted after clearance of infection and could directly contribute to host cell transformation. In particular, human telomerase catalytic subunit (hTERT) mRNA expression and catalytic subunit activity were increased in acute infected late passage IMR90E1A cells. hTERT upregulation was accompanied by recruitment of ceramide, a known regulator of hTERT, to the chlamydial inclusion and was abrogated following doxycycline-mediated infection clearance. In cells cleared of Ctr infection, average telomere length was slightly increased and immunofluorescence staining of the DNA damage marker γH2A.X was reduced after clearance of infection compared with cells that had not been infected. Reduced p53 binding to the promoter of the cell cycle checkpoint regulator p21 was also detected in cells cleared of infection and p21 levels were reduced; moreover, this cell population exhibited increased resistance to etoposide-induced DNA damage. Thus, Ctr infection altered cell aging and survival pathways, which persisted after infection clearance. Cells that survive infection are likely to exhibit altered physiology, as evidenced by an increased resistance to DNA damage-induced apoptosis, which may support cellular transformation.     

Overview of high-risk HPV's 16 and 18 infected cervical cancer: Pathogenesis to prevention

As general, the Human papillomavirus (HPV) causes the most sexually transmitted diseases. Among well categorized 80 types, the high-risk types HPV's 16 and 18 are highly involved in 70% of cervical cancer. The virulence of HPV is mainly exhibited by E5, E6 and E7 encoded oncoproteins that cause low to high-grade cervical lesions (CIN-1, 2, 3), leading to form 99.7% of squamous cell and 89% of adenocarcinomas cervical cancer worldwide. This study mainly encircles the major role of E5, E6 and E7 oncoproteins in HPV 16 and 18. Further discussed the uprising of significant biomarkers and their cellular process in different stages of cervical cancer with current prevention and treatment regimens. Hence, this integration will evoke novel markers, potential vaccination and various treatments approaches with special reference for HPV16 and 18 infected cervical cancers.     

Telomeres and Telomerase Biology in Vertebrates: Progress Towards a Non-Human Model for Replicative Senescence and Ageing

Studies on telomere and telomerase biology are fundamental to the understanding of human ageing and age-related diseases such as cancer. However, human studies of whole body ageing are hampered by the lack of suitable fully reflective animal model systems, the wild-type mouse model being unsuitable due to differences in telomere biology. Here we summarise recent data on the biology of telomeres, telomerase, and the tumour suppressor protein p53 in various animals, and examine their possible roles in replicative senescence, ageing, and tumourigenesis. The advantages and disadvantages of various animals as model systems for whole body ageing in humans are discussed.     

人类端粒酶逆转录酶hTERT Ki-67及p27^kipl在嗜铬细胞瘤组织的表达及意义研究

目的 研究人端粒酶逆转录酶（hTERT）、Ki-67及p27^kipl的表达在嗜铬细胞瘤发生与发展中的作用和作为预测生物学行为标志物的价值。方法 采用免疫组织化学方法检测hTERT、Ki-67及p27^kipl在2000-2004年广西医科大学第一附属医院病理科的45例嗜铬细胞瘤和神经节细胞瘤及9例正常肾上腺组织中的表达。结果 hTERT蛋白的表达在良性（3／31例）和可疑恶性（6／7例）以及良性与恶性肿瘤（5／7例）间的差异均有统计学意义（P〈0.01）。31例良性肿瘤中26例未检测到Ki-67，而恶性肿瘤和可疑恶性肿瘤均为阳性；Ki-67与hTERT的表达呈正相关性（r=0．544，P〈0．01）。恶性和可疑恶性肿瘤中未检测到p27^kipl，5例良性肿瘤为阳性，所有正常肾上腺髓质标本均可检测到p27^kipl的表达。p27^kipl与hTERT的表达无相关性。结论 端粒酶的激活在恶性嗜铬细胞瘤和神经节细胞瘤的发生发展中起着重要作用，在细胞周期调控中端粒酶可能存在不同的激活途径。hTElit和Ki-67的检测可作为鉴别良恶性嗜铬细胞瘤的手段。     

hTERT-siRNA表达载体的构建及对MCF-7细胞生长、端粒酶活性的抑制作用

目的 构建人端粒酶逆转录酶(hTERT)基因的RNA干扰(RNAi)表达载体,并研究该载体对乳腺癌MCF-7细胞端粒酶活性及细胞增殖的影响,为针对端粒酶的乳腺癌基因治疗提供新的途径.方法 设计针对人端粒酶逆转录酶催化亚基(hTERT)的干扰靶序列TGTTCAGCGTGCTCAACTA,构建重组siRNA表达质粒pGenesil-hTERT,同时构建不针对任何基因的阴性对照重组pGenesiL-HK.两种重组质粒经酶切、电泳分析和测序鉴定后,用脂质体转染法分别转染乳腺癌MCF-7细胞,应用端粒酶重复序列扩增聚合酶链反应(TRAP-PCR)及聚丙烯酰胺凝胶电泳检测端粒酶活性,流式细胞仪测定细胞凋亡率.结果 酶切电泳测序分析表明插入序列正确,重组质粒构建成功.转染pGenesil-hTERT的MCF-7细胞,凝胶电泳见端粒酶特征性条带明显减少,端粒酶活性受到明显抑制pGenesil-hTERT转染细胞后凋亡率较对照组明显升高(P＜0.01),且转染48h凋亡率最高,达54.7%±2.41%.结论 hTERT-siRNA可有效抑制乳腺癌MCF-7细胞端粒酶活性、促进细胞凋亡,此法有望应用于肿瘤基因治疗.