HPV16 E6E7抗原表达模型的建立

目的 用基因重组技术构建pcDNA-E6E7真核表达载体.方法 经限制性内切酶和序列分析,用脂质体转染技术将其转入B16细胞,G418稳定筛选后IFA法检测其表达,RT-PCK法检测HPV16E6E7mRNA的生成,并将转染细胞接种小鼠皮下,观察成瘤情况.结果 酶切鉴定证实重组质粒中插入的目的基因片段及载体大小、方向和插入住点均正确,在转染的B16细胞中可见绿色荧光并检测到HPV16E6E7mRNA的生成,接种的转染细胞在小鼠皮下100%成瘤.结论 提示B16细胞转染E6E7后其致瘤性与转染空载体组和野生型B16细胞组无明显差异.     

HPV16/18和HPV16E6/E7DNA在宫颈癌组织中的表达

目的检测HPV16/18和HPV16E6/E7 DNA在宫颈癌组织中的表达,探讨其在宫颈癌发病中的作用.方法应用PCR和琼脂糖凝胶电泳方法检测46例宫颈癌组织中HPV16/18和HPV16E6/E7DNA.结果 46例宫颈癌中56.5%(26/46)扩增HPV16/18 DNA,其中宫颈鳞癌25例,宫颈腺癌1例.正常对照组20例HPV16/18DNA均为阴性,与宫颈癌组相比差异有显著性(P<0.01).HPV16/18 DNA阳性拷贝对数值为4.32±2.45.HPV16E6,E7DNA分别有53.8%(14/26)、46.2%(12/26)扩增.结论 HPV16/18和HPV16E6/E7 DNA与宫颈癌的发生密切相关,是宫颈癌恶性转化的关键之一,预示着宫颈癌有较强的增殖能力和转移能力.     

HPV58 E6的基因克隆及HLA-DQB1*03限制性T细胞表位分析

目的:克隆HPV58E6的基因,并对其HLA-DQB1*03限制性T细胞表位进行分析。方法:从宫颈癌组织中提取基因组DNA,通过PCR方法扩增HPV58E6基因,常规方法将目的基因插入pGEM-TEasy载体中。酶切和测序鉴定后,利用位置特异性分数矩阵(PSSM)理论、支持向量机(SVM)理论和蛋白酶体酶切位点预测算法分析HPV58E6的HLA-DQB1*03限制性T细胞表位。结果:成功克隆了1株HPV58E6基因(GenBank EF060239),表位47FADLRIAY-RDGNPFA和表位102RCIICQRPLCPQEKK理论上是其HLA-DQB1*03限制性T细胞表位。结论:这两个表位可望作为后续相关实验中表位筛选、鉴定和多肽疫苗研制的候选对象。     

中国地方株人乳头瘤病毒16型E7基因一级结构及其变异

从湖北地区一宫颈癌活检组织中提取ＤＮＡ，采取加端聚合链反应（Ａｄｄ－ｏｎ ＰＣＲ）技术，获得了人乳头瘤病毒１６型E７基因（ＨＰＶＩ６Ｅ７）。将该基因克隆于载体ｐＵＣ１８后，进行了该基因一级结构顺序分析。完整的ＨＰＶ１６Ｅ７湖北株基因（ＨＰＶ１６Ｅ７－ＨＢ）全长２９４ｂｐ，与已发表的德国株（ＧＳ）大小一致，但其核苷酸顺序中有２处发生了变异，均为Ｃ→Ｔ变异。第４３位ＣＡＡ→ＴＡＡ使相应的谷氨酰胺密码子变为终止密码，形成无义突变（Ｎｏｎｓｅｎｓｅｍｕｔａｔｉｏｎ）。将重组质粒中０．３ｋｂ的ＨＰＶ１６Ｅ７基因在表达载体ＰＷＲ５９０－１中进行克隆，经诱导使重组表达质粒在大肠杆菌中高效表达，得到了预计的、分子量约为６９×１０~３的融合蛋白。该蛋白的表达量占菌体总蛋白量的３０％左右。该试验表明ＨＰＶ１６Ｅ７一级结构以及所编码的蛋白多肽在不同的国家和／或不同的地区可能存在着差异。本文首次报道了中国地方株ＨＰＶ１６Ｅ７基因的一级结构。     

HPV16 E6 natural variants exhibit different activities in functional assays relevant to the carcinogenic potential of E6

Genetic studies have revealed natural amino acid variations within the human papillomavirus (HPV) type 16 E6 oncoprotein. To address the functional significance of E6 polymorphisms, 10 HPV16 E6 variants isolated from cervical lesions of Swedish women were evaluated for their activities in different in vitro and in vivo assays relevant to the carcinogenic potential of E6. Small differences between E6 prototype and variants, and among variants, were observed in transient expression assays that assessed p53 degradation, Bax degradation, and inhibition of p53 transactivation. More variable levels of activities were exhibited by the E6 proteins in assays that evaluated binding to the E6-binding protein (E6BP) or the human discs large protein (hDlg). The E6 prototype expressed moderate to high activity in the above assays. The L83V polymorphism, previously associated with risk for cancer progression in some populations, expressed similar levels of activity as that of the E6 prototype in most functional assays. On the other hand, L83V displayed more efficient degradation of Bax and binding to E6BP, but lower binding to hDlg. Results of this study indicate that naturally occurring amino acid variations in HPV16 E6 can alter activities of the protein important for its carcinogenic potential.     

HPV16 E6 augments Wnt signaling in an E6AP-dependent manner

In this study we investigated the effect of HPV16 E6 on the Wnt/β-catenin oncogenic signaling pathway. Luciferase reporter assays indicated that ectopically expressed E6 significantly augmented the Wnt/β-catenin/TCF-dependent signaling response in a dose-dependent manner. This activity was independent of the ability of E6 to target p53 for degradation or bind to the PDZ-containing E6 targets. Epistasis experiments suggested that the stimulatory effect is independent of GSK3β or APC. Coexpression, half-life determination, cell fractionation and immunofluorescence analyses indicated that E6 did not alter the expression levels, stability or cellular distribution of β-catenin. Further experiments using E6 mutants defective for E6AP binding and E6AP knockdown cells indicated the absolute requirement of the ubiquitin ligase E6AP for enhancement of the Wnt signal by E6. Thus, this study suggests a role for the E6/E6AP complex in augmentation of the Wnt signaling pathway which may contribute to HPV induced carcinogenesis.     

HPV mRNA检测在宫颈癌诊断中的研究

根据国际癌症研究机构(IARC)报道,仅在2012年全世界就有超过25万女性死于宫颈癌,这是女性相关癌症的第四大死因[1].不管是生物学研究还是流行病学研究都已经证实宫颈癌与人乳头瘤病毒(HPV)感染息息相关[2]l.单独的HPV感染可能会引起大约5％的病毒相关的癌症发生,但是却是宫颈癌发病的全部因素[3].目前已经有120多种不同基因型的HPV,根据其临床表现可分为低风险型和高风险型,然而只有少数的HPV能够导致癌症的发生[4].本文就HPV致宫颈癌的发生和HPV的实验室检查以及HPV mRNA的相关进展做一些简要论述.     

人乳头状瘤病毒18型E6E7基因诱导胎儿食管永生化上 …

目的 ＳＨＥＥ细胞系是经人乳头状瘤病毒（ＨＰＶ）１８型Ｅ６Ｅ７基因诱导的永生化上皮细胞株,已传代超过５０代。研究胎儿食管上皮永生化的细胞 ＳＨＥＥ生物学特性,包括增殖,分化和调亡。方法 细胞于１９９培养基培养,用光镜、电镜和荧光显微镜研究其生长率、形态和染色体分析;用流式细胞仪研究其细胞增殖动力学;用免疫组织化学方法研究Ｋｉ６７和角蛋白和用末端转移酶标记（ＴＵＮＥＬ）凋亡细胞。结果 细胞培养呈单导     

pcDNA3/HPV16 E6真核表达质粒的构建及裸DNA注射动物实验观察

目的探讨ＨＰＶ１６Ｅ６基因ＤＮＡ诱发体液和细胞免疫反应的能力。方法利用基因工程技术构建了ＨＰＶ１６Ｅ６真核表达质粒ｐｃＤＮＡ３／Ｅ６，脂质体法转染Ｃｏｓ７细胞，肌肉注射免疫ＢＡＬＢ／ｃ小鼠，免疫组化技术检测抗体产生及抗原表达。结果被转染的Ｃｏｓ７细胞表达ＨＰＶ１６Ｅ６蛋白免疫小鼠产生抗ＨＰＶ１６Ｅ６抗体。结论这一结果为ＨＰＶ１６相关宫颈癌治疗性ＤＮＡ疫苗的研制提供了资料。     

Characterization of the plasma membrane localization and orientation of HPV16 E5 for cell-cell fusion

Human papillomavirus (HPV) is a non-enveloped DNA virus with an ∼ 8000 base pair genome. Infection with certain types of HPV is associated with cervical cancer, although the molecular mechanism by which HPV induces carcinogenesis is poorly understood. Three genes encoded by HPV16 are regarded as oncogenic — E5, E6, and E7. The role of E5 has been controversial. Expression of HPV16 E5 causes cell-cell fusion, an event that can lead to increased chromosomal instability, particularly in the presence of cell cycle checkpoint inhibitors like HPV16 E6 and E7. Using biochemical and cell biological assays to better understand HPV16 E5, we find that HPV16 E5 localizes to the plasma membrane with an intracellular amino terminus and an extracellular carboxyl-terminus. Further, HPV16 E5 must be expressed on both cells for cell fusion to occur. When the extracellular epitope of HPV16 E5 is targeted with an antibody, the number of bi-nucleated cells decreases.     

Expression of HPV16 E5 produces enlarged nuclei and polyploidy through endoreplication

Anogenital cancers and head and neck cancers are causally associated with infection by high-risk human papillomavirus (HPV). The mechanism by which high-risk HPVs contribute to oncogenesis is poorly understood. HPV16 encodes three genes (HPV16 E5, E6, and E7) that can transform cells when expressed independently. HPV16 E6 and E7 have well-described roles causing genomic instability and unregulated cell cycle progression. The role of HPV16 E5 in cell transformation remains to be elucidated. Expression of HPV16 E5 results in enlarged, polyploid nuclei that are dependent on the level and duration of HPV16 E5 expression. Live cell imaging data indicate that these changes do not arise from cell-cell fusion or failed cytokinesis. The increase in nuclear size is a continual process that requires DNA synthesis. We conclude that HPV16 E5 produces polyploid cells by endoreplication. These findings provide insight into how HPV16 E5 can contribute to cell transformation.     

HPV18型E2蛋白高表达对巨噬细胞凋亡及其分泌功能的影响

目的:研究HPV18 E2及其N端(TAD)、C端(DBD)与GFP融合蛋白瞬时高表达对巨噬细胞(MΦ)凋亡及分泌活性的影响,为进一步研究E2蛋白在HPV18致癌机制中的作用奠定实验基础.方法:通过PCR从现有真核表达载体pEGFP-C1/E2上分别扩增出TAD、DBD基因片段,并构建真核表达载体pEGFP-C1/TAD、pEGFP-C1/DBD.将3种真核表达载体及pEGFP-C1分别转染MΦ,用倒置荧光显微镜观察它们的表达与定位,并以抗GFP抗体为一抗作Western blot检测它们的表达.通过3种融合蛋白在MФ内的瞬时高表达,在转染48 h后分别检测各组细胞培养基中TNF-α和IL-1β的含量,并收集MΦ经染色以及流式细胞术(FCM)观察检测其凋亡.结果:GFP-E2融合蛋白主要表达于细胞核,细胞质内也有表达,而GFP-DBD融合蛋白仅表达于细胞核内,GFP-TAD仅表达于细胞质.GFP-E2、GFP-TAD融合蛋白在MΦ内高表达后MΦ凋亡率上升,细胞因子TNF-α和IL-1β分泌量增加,且GFP-TAD作用强于GFP-E2.而EGFP-DBD无此作用.结论:HPV18 E2及其TAD与EGFP融合蛋白瞬时高表达可诱导MΦ凋亡并上调其分泌细胞因子TNF-α和IL-1β.     

Stabilization of HPV16 E6 protein by PDZ proteins, and potential implications for genome maintenance

The E6 protein from high-risk human papillomaviruses appears necessary for persistence of viral episomes in cells but the underlying mechanism is unclear. E6 has many activities, including its ability to bind and degrade PDZ domain-containing proteins, such as hScrib. However little is known about the role of these interactions for E6 function and the viral life cycle. We now show that the levels of expression of wild-type E6 are increased in the presence of hScrib whilst a mutant E6 protein lacking the PDZ-binding motif is found at lower levels as it is turned over more rapidly by the proteasome. This correlates with an inability of genomes containing this mutation to be maintained as episomes. These results show that E6 association with certain PDZ domain-containing proteins can stabilize the levels of E6 expression and provides one explanation as to how the PDZ-binding capacity of E6 might contribute to genome episomal maintenance.     

DNA virus oncoprotein HPV18 E7 selectively antagonizes cGAS-STING-triggered innate immune activation

Cellular infections by DNA viruses trigger innate immune responses mediated by DNA sensors. The cyclic GMP–AMP synthase (cGAS)-stimulator of interferon gene (STING) signaling pathway has been identified as a DNA-sensing pathway that activates interferons in response to viral infection and, thus, mediates host defense against viruses. Previous studies have identified oncogenes E7 and E1A of the DNA tumor viruses, human papillomavirus 18 (HPV18) and adenovirus, respectively, as inhibitors of the cGAS-STING pathway. However, the function of STING in infected cells and the mechanism by which HPV18 E7 antagonizes STING-induced Interferon beta production remain unknown. We report that HPV18 E7 selectively antagonizes STING-triggered nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) activation but not IRF3 activation. HPV18 E7 binds to STING in a region critical for NF-κB activation and blocks the nuclear accumulation of p65. Moreover, E7 inhibition of STING-triggered NF-κB activation is related to HPV pathogenicity but not E7–Rb binding. HPV18 E7, severe acute respiratory syndrome coronavirus-2 open reading frame 3a, human immunodeficiency virus-2 viral protein X, and Kaposi's sarcoma-associated herpesvirus KSHV viral interferon regulatory factor 1 selectively inhibited STING-triggered NF-κB or IRF3 activation, suggesting a convergent evolution among these viruses toward antagonizing host innate immunity. Collectively, selective suppression of the cGAS-STING pathway by viral proteins is likely to be a key pathogenic determinant, making it a promising target for treating oncogenic virus-induced tumor diseases.     

siRNA抑制HPV18 E6基因及其对HeLa细胞凋亡的影响

目的研究特异小干扰RNA(sm all interfering RNA,siRNA)对宫颈癌HeLa细胞中人乳头瘤病毒(hum an pap-illom avirus,HPV)18型E6基因的抑制及其对细胞凋亡的影响。方法针对HPV18E6基因设计siRNA序列,经PCR方法体外扩增,得到含有U6启动子以及siRNA序列的PCR产物,利用L ipofectam ineTM2000脂质体转染HeLa细胞,在U6启动子的作用下于细胞内转录siRNA。针对转染后不同时间点采用四唑盐(MTT)比色法测定细胞活力,流式细胞仪PI染色法检测细胞凋亡率,RT-PCR测定HPV18E6 mRNA变化。结果转染siRNA后细胞活力受到显著抑制(P<0.05),光镜下出现明显的凋亡形态,72 h的凋亡率达到55.8%。RT-PCR结果显示,细胞转染24、48和72 h后HPV18E6 mRNA分别减少了57%、78%和40%,而siRNA阴性对照与未转染细胞相比差异不显著。结论siRNA可特异有效的干扰宫颈癌HeLa细胞内HPV18E6基因的表达,从而可诱导肿瘤细胞凋亡。     

含HPV16 E7的嵌合型VLPs引发细胞溶解反应

目的 探讨ＢＰＶ（牛乳头状瘤病毒）Ｌ１／ＨＰＶ（人乳头状瘤病毒）１６Ｅ７嵌合型乳头状瘤病毒样颗粒（ＶＩＰｓＸ）的免疫学特性。方法 将表达纯化的含ＢＰＶＬ１／ＨＰＶ１６Ｅ７的嵌合型ＶＬＰｓ作为抗原在体外刺激ＥＬ－４细胞并对其进行细胞毒性Ｔ淋巴细胞（ＣＴＬ）反应分析。结果 嵌合型ＶＬＰｓ可引发特异的ＣＴＬ反应。Ｌ１－ＶＬＰｓ抗体能阻断这种特异性细胞溶解反应。结论 含ＢＰＶＬ１／ＨＰＶ１６Ｅ７嵌合型的Ｖ