Human papillomavirus type 16 E6 and E7 gene variations in Indian cervical cancer

OBJECTIVES: Human papillomavirus type 16 is a causative factor for development of cervical cancer. The E6 and E7 genes of HPV 16 are critical to the process of immortalization and transformation of host cells. Recent reports suggest that variants of these two genes may contribute to the risk of malignant progression of cancer in the uterine cervix. However, no data exist on sequence variations of HPV 16 E6 and E7 genes that may exist in India. Therefore, we examined intratype variations in the E6 and E7 viral genes in DNA isolated from HPV 16-positive cervical scrapes and biopsies. METHODS: The open reading frames of the E6 and E7 genes were amplified by PCR and then directly sequenced by the fluorescent dye dideoxy termination method.Results. In addition to the prototype E6 gene sequence, five sets of mutations of the E6 gene were identified. The European prototype (350T) was detected in 9.1% of the study group while the European variant (350G) was seen in 28% of patients. The remaining variants (a combination of the 350G mutation with 335T, 145T, or 419G) were significantly associated with cases compared to controls. The 350G + 145T variant was found at much higher incidence in cases in younger women, suggesting that this variant may be associated with aggressive tumor behavior. Interestingly the 350G + 419G combination was found only in controls. There was no significant association between the four genotypes of E7 and any stage of tumor progression or age. CONCLUSIONS: The results indicate that specific mutations in the E6 gene are found in young Indian women with high-grade squamous intraepithelial lesions and invasive cancer, suggesting that these mutations represent more oncogenically active HPV 16. Whether this increased oncogenecity is due to differences in p53 inactivation, ineffective keratinocyte differentiation, and/or altered response to the immune system by these oncogenic E6 mutants remains to be clarified.     

腺病毒伴随病毒表达载体表达人乳头状瘤病毒16型E6/E7基因的构建及应用

目的　为了了解人乳头状瘤病毒 (Humanpapillomavirus ,HPV) 1 6型的E6 /E7基因在细胞恶性转化中所起的作用 ,利用腺病毒伴随病毒载体 (AAVHelper -FreeSystem)构建和表达人乳头状瘤病毒 1 6型E6 /E7基因。方法　在pLXSN1 6E6E7质粒中经PCR扩增回收HPV 1 6E6E7基因片段 ,连接于T载体上进行测序 ,将正确的HPV 1 6E6E7插入pAAV -IRES -hrGFP质粒 ,协同pAAV -RC质粒和pHelper质粒共转染HEK 2 93细胞 ,包装表达HPV 1 6E6E7基因的重组腺病毒伴随病毒 ,收获病毒 ,并检测病毒的感染效率。结果　在包装细胞系HEK 2 93细胞中能形成较高感染效率的腺病毒伴随病毒 ,激光共聚焦检测可发现HEK 2 93细胞内有绿色荧光蛋白表达 ,HEK 2 93细胞经PCR可扩增出特异性的HPV 1 6E6E7基因片段 ,经流式细胞仪检测重组病毒的感染效率为71 3%。结论　携带人乳头状瘤病毒 1 6型E6E7基因的腺病毒伴随病毒可感染细胞 ,并在细胞内表达 ,可望用于宫颈癌病因学的研究     

宫颈癌及癌前病变组织中Notch1及HPV16 E6/E7表达的研究

目的 探讨Notch1受体和人乳头瘤病毒16感染在宫颈癌前病变和宫颈癌发生发展中的作用。方法 采用免疫组化SP法检测18例宫颈上皮内瘤变（cervical intraepithelial neoplasia,CIN）和35例宫颈癌标本中Notch1受体及HPV16E6/E7蛋白的表达,以34例正常宫颈组织及慢性宫颈炎组织作为对照。比较各组间Notch1及HPV16E6/E7表达的差异,并分析Notch1与HPV16E6/E7表达的关系。结果 Notch1蛋白在细胞胞浆、胞核及胞膜中表达,HPV16E6/E7在细胞核中表达。从对照组到CIN组到宫颈癌组,Notch1及HPV16E6/E7的表达均逐渐增强（P〈0.01）。Notch1的阳性表达与宫颈癌不同分期、分化程度、淋巴结是否转移无关（P〉0.05）。在宫颈癌组中Notch1与HPV16E6/E7的表达均呈正相关性（P〈0.01）。结论 Notch1表达与HPV16E6/E7感染可能与CIN及宫颈癌的发生密切相关,两者在宫颈癌的发病机制中可能协同发挥作用。     

Polymorphism in the E6 gene of human papillomavirus type 16 in the cervical tissues of Korean women

The aim of this study was to identify sequence variants in the HPV 16 E6 gene in Korean women and to examine the possible association between these sequence variants and cervical cancer development. We examined the HPV 16 DNA of 215 patients with no cervical disease (NCD) (n = 105) or with cervical neoplasia (n = 110) [cervical intraepithelial neoplasia (CIN), n = 61; invasive cervical carcinoma (ICC), n = 49] using the nested polymerase chain reaction (PCR) and PCR-directed sequencing methods. Fifty-four (NCD, n = 10; CIN, n = 17; ICC, n = 27) of the 215 samples contained HPV 16 E6 DNA, but only two (7.4%) of 27 ICC samples had prototype sequences. The most frequently found variation was D25E (in NCD, n = 8, 80%; in CIN, n = 9, 52.9%; in ICC, n = 23, 85.2%). This is a rare variation in western countries. No significance difference was found between the frequencies of D25E variation in cancerous and non-cancerous lesions. Among the 11 kinds of variants identified, four variants were novel and have been registered with GenBank. This study demonstrates that the D25 variant is the most prevalent E6 genomic variant type in Korean population. However, it was not found to be associated with an increased risk of ICC.     

IgG antibodies against human papillomavirus type 16 E7 proteins in cervicovaginal washing fluid from patients with cervical neoplasia

Abstract. Tjiong MY, ter Schegget J, Tjong-a-Hung SP, Out TA, van der Vange N, Burger MPM, Struyk L. IgG antibodies against human papillomavirus type 16 E7 proteins in cervicovaginal washing fluid from patients with cervical neoplasia.
Little information is available about the cervicovaginal mucosal antibodies against human papillomavirus (HPV) proteins. In this study specific IgG antibodies against HPV 16 E7 protein were determined in paired samples of cervicovaginal washing fluid and serum from patients with cervical cancer ( n = 22), cervical intraepithelial neoplasia (CIN) ( n = 38), healthy individuals ( n = 22), and serum from children ( n = 41) by a radioactive immunoprecipitation assay (RIPA). HPV 16 E7 specific IgG antibodies were found in cervicovaginal washings ( n = 8) and in sera ( n = 8) of the patients with cervical cancer. About 60% of the patients with HPV 16 positive cervical cancer had HPV 16 E7 specific IgG antibodies. Titration studies showed that the IgG antibody reactivity in cervicovaginal washings was higher than in the paired serum samples of six patients with cervical cancer ( P < 0.001). In the CIN group we found no IgG reactivity in the serum, but in five patients we found a low IgG reactivity in the cervicovaginal washings. No IgG reactivity was found in cervicovaginal washings and sera from healthy individuals and sera from children. HPV 16 E7 specific IgG antibodies seem to be locally produced in a number of patients with HPV 16 positive (pre)malignant cervical lesions. For more definitive evidence for the local production of these antibodies immunostaining should be performed to demonstrate the presence of specific anti-HPV 16 E7 IgG producing plasma cells in the cervical epithelium.     

反义HPV16 E6/E7-EGFP重组质粒的构建及其对宫颈癌SiHa细胞的促凋亡作用

目的:构建HPV16早期基因E6/E7的反义重组质粒,探讨其对SiHa细胞的促凋亡作用。方法:将HPV16E6/E7基因片段反向克隆于真核表达载体pEGFP-C1并转染SiHa细胞,用RT-PCR方法检测转染后SiHa细胞E6、E7基因mRNA的表达,West-ernblot方法检测转染后E6/E7蛋白的表达,流式细胞仪检测转染后细胞的凋亡率。结果:成功构建携带HPV16E6/E7基因反义片段的真核表达载体,转染该质粒后,SiHa细胞E6、E7基因的mRNA和蛋白均明显下调;转染后细胞凋亡率为(59.3±11.3)%,明显高于转染空载体组[(9.4±1.8)%]和未转染组[(2.1±0.4)%](P<0.05)。结论:反义HPV16E6/E7基因可下调宫颈癌细胞中E6/E7癌基因的表达,诱导宫颈癌细胞凋亡,为宫颈癌的基因治疗提供了实验依据。     

Viral DNA load, physical status and E2/E6 ratio as markers to grade HPV16 positive women for high-grade cervical lesions

OBJECTIVES: Cervical intraepithelial neoplasias (CIN) associated with high-risk (HR) human papillomavirus infection, in addition to HR-HPV typing need other viral marker testing to distinguish a subset of lesions with clinical relevant infections. This study has evaluated the significance of viral markers, such as viral load, physical status and E2/E6 ratio, to stratify HPV16 infected women at a single point in time for grade of cervical lesions. METHODS: One hundred sixty-six cytological specimens were selected from women with low (n=72) and high (n=94) grade squamous intraepithelial lesions (SIL), and positive to HPV16. All the 72 LSIL were CINI, 83 of the 94 HSIL were CINII/III and 11 SCC (Squamous Cervical Carcinoma). Cytological specimens were analysed by two different SYBR Green Real-time PCR assays (RT-PCR). Specific primers for both E2 and E6 viral genes and GAPDH cellular gene were designed to determine viral load, physical status and E2/E6 ratio. RESULTS: The viral load was significantly higher in HSIL than in LSIL. In CINI episomal DNA was prevalent (72.2%), mixed forms (episomal and integrated) were 27.8%, suggestive of an early integration of viral DNA into cellular genome, no pure integrated forms were detected. However in CINII/III mixed DNA forms were prevalent (73.5%). In SCC pure integrated DNA was prevalent (81.8%) in absence of episomal forms. E2/E6 ratio decreased significantly from CINI to CINII/III and SCC with a linear trend. The logistic regression analysis showed that viral load higher than 1.38x10(6) genome copies per 300 ng of total DNA associated with E2/E6 ratio lower than 0.90 was highly significant in differentiating CINII/III versus CINI, while the only E2/E6 value lower than 0.17 was significant in differentiating SCC from CINI. CONCLUSIONS: Viral load higher than 1.38x10(6) genome copies per 300 ng of total DNA and E2/E6 ratio values allow HPV16 infected women with high grade cervical intraepithelial lesions to be recognized.     

Quantification of intracellular HPV E6/E7 mRNA expression increases the specificity and positive predictive value of cervical cancer screening compared to HPV DNA

Objectives

Current methods for HPV screening rely on the detection of L1 DNA from high risk genotypes (HRHPV). These assays have very high negative predictive values (~ 99%), however, the specificity and positive predictive value of HPV DNA tests for pre-cancerous and cancerous lesions (CIN 2+) is less than 50%. The purpose of this study was to compare HPV DNA with intracellular HPV E6, E7 mRNA quantification in an effort to improve the performance of cervical cancer screening.

Methods

Liquid-based cervical cytology specimens collected in either PreservCyt or SurePath were processed for routing cytology, HPV HRDNA detection by Hybrid Capture 2 and HPV E6, E7 mRNA quantification in cells using the same sample. We analyzed a total of 2049 samples including 73 with CIN 2, CIN 3, or squamous cell carcinoma by biopsy and 1694 samples from women with normal cytology.

Results

The positive predictive value of HPV E6, E7 mRNA quantification in cells for CIN2+ was 78% which was greater than HPV DNA alone (43%). The specificity of HPV E6, E7 mRNA quantification was 96% based on normal cytology compared to 82% for HC2 while the specificity of HPV E6, E7 mRNA quantification based on CIN 2− histology was 85% compared to 35% for HC2.

Conclusions

With similar sensitivity and greater specificity/positive predictive value, HPV E6, E7 mRNA quantification in cells is an improvement over HPV DNA for cervical cancer screening.     

青岛地区不同宫颈病变组织中HPV16 E2基因突变分析

目的:探讨山东省青岛地区不同宫颈病变组织中人乳头瘤病毒16型(HPV16)E2基因序列多态性,以及序列变异与不同宫颈病变的关系。方法:提取257例宫颈脱落细胞及宫颈癌组织DNA,PCR进行HPV分型,其中HPV16阳性标本扩增E2基因,测定PCR产物序列。通过DNAStar生物软件进行核苷酸和氨基酸序列分析。结果:共检测出11个碱基突变位点,其中10个导致氨基酸的改变,突变热点为nt3410(63.2%),nt3159(55.9%),nt3249(55.9%)。统计学分析显示,各个位点的突变与不同级别宫颈病变之间均无相关性(P>0.05)。宫颈癌标本中基因整合率为[65%(14/40)],远高于CINⅢ的整合率[14%(6/43)](P<0.001)。结论:青岛地区HPV16 E2基因存在多个位点的突变,且发现G2828A,T3274G,T3384C,T3524C为青岛地区特异性突变,这些位点的突变可能与高度上皮内瘤变和浸润性宫颈癌的发生和发展有关。     

高危型人乳头瘤病毒E6/E7 mRNA在宫颈细胞学ASCUS/LSIL/ASC-H分流中的意义

目的:比较高危型人乳头瘤病毒(HR-HPV)E6/E7 mRNA与HR-HPV DNA检测在宫颈病变筛查中的诊断性能。探讨其在宫颈细胞学ASCUS/LSIL/ASC-H分流中的意义。方法:收集2016年5月至11月就诊于清华长庚医院妇科的液基细胞学结果为ASCUS、LSIL、ASC-H的患者251例,分别行宫颈脱落细胞HR-HPV DNA、HR-HPV E6/E7mRNA检测,并行阴道镜检查及宫颈活体组织检查,以组织学病理为金标准。结果:HRHPV E6/E7 mRNA阳性率在ASCUS、LSIL和ASC-H中分别为18.34%(20/108)、28.82%(30/102)和39.51%(17/41)。宫颈活检病理结果子宫颈低级别病变(湿疣/CIN1组)与高级别病变(CIN2/3)组的HR-HPV E6/E7 mRNA阳性率比较,差异有统计学意义(P=0.0125)。以子宫颈活检的组织学诊断结果为金标准,HR-HPV E6/E7 mRNA筛查子宫颈高级别病变的特异性及阳性预测值均明显高于HPV-DNA。ASCUS/LSIL/ASC-H中,HRHPV E6/E7 mRNA检测筛查宫颈高级别病变的ROC曲线面积均大于HPV-DNA,诊断效能优于HPV-DNA。结论:HPV E6/E7 mRNA检测诊断宫颈高级别病变的特异性及阳性预测值高于HPV-DNA,能辅助宫颈细胞学筛查及HPV-DNA,提高宫颈高级别病变诊断的特异性,在细胞学检查阶段对患者做出有效分流,预测宫颈高级别病变。     

Cancerous inhibitor of protein phosphatase 2A is overexpressed in cervical cancer and upregulated by human papillomavirus 16 E7 oncoprotein

Objectives

Cancerous inhibitor of protein phosphatase 2A (CIP2A) is a recently identified oncoprotein stabilizing c-Myc and promoting cell proliferation and transformation. Here we investigated the role of CIP2A in cervical cancer in vivo and in vitro.

Methods

CIP2A expression was assessed in normal cervical, cervical intraepithelial neoplasia (CIN) I to III and cervical cancer tissues by immunohistochemistry and RT-PCR. Cell growth was explored by cell proliferation assay, colony formation assay and anchorage-independent growth in soft agar after inhibition of CIP2A by siRNA in HeLa, SiHa and Caski cells. Crosstalk of CIP2A and HPV16 E7 was investigated by immunohistochemistry in cervical cancer tissues and by real-time PCR and western blot analysis after HPV16 E7 inhibition by siRNA in SiHa cells.

Results

CIP2A was transcribed in 73.3% of cervical cancer tissues (n = 15) but not in normal cervical tissues (n = 8). CIP2A protein was detected in 52.8% of cervical cancer (n = 72) and 12.5% of CIN III tissues (n = 24) but not in normal (n = 15), CIN I (n = 21) or CIN II samples (n = 25). CIP2A protein level was positively associated with HPV16 E7 level in cervical cancer tissues. CIP2A expression was markedly reduced after E7 depletion. Moreover, CIP2A depletion reduced c-Myc protein level and impaired proliferation and growth of cervical cancer cells.

Conclusions

CIP2A is overexpressed in cervical cancer and promotes the malignant growth of cervical cancer cells. Its expression is upregulated by HPV16 E7. Therefore, CIP2A plays an important role in carcinogenisis of cervical cancer and shows promise for the diagnosis and treatment of cervical cancer.     

HPV16/18 E7-pulsed dendritic cell vaccination in cervical cancer patients with recurrent disease refractory to standard treatment modalities

OBJECTIVE: To evaluate the potential of human papillomavirus (HPV) type 16 and 18 E7 antigen-loaded autologous dendritic cells (DC) as a therapeutic cellular vaccine in a case series of cervical cancer patients harboring recurrent/metastatic disease refractory to standard treatment modalities. METHODS: Autologous monocyte-derived DC were pulsed with recombinant HPV16 E7 or HPV18 E7 oncoproteins and administered to 4 cervical cancer patients. Vaccinations were followed by subcutaneous administration twice daily of low doses of human recombinant interleukin-2 (1 x 10(6) IU/m2) from day 3 to day 7. Safety, toxicity, delayed type hypersensitivity reactions (DTH), clinical responses, and induction of serological and cellular immunity against HPV16/18 E7 were monitored. RESULTS: The vaccine was well-tolerated in all patients and no local or systemic side effects or toxicity were recorded. Three out of four patients were found to be significantly immunocompromised before starting the vaccination treatment, as assessed by DTH with a panel of recall antigens. Specific humoral and cellular CD4+ T cell responses to the E7 vaccine were detected in 2 patients, as detected by ELISA and by IFN-gamma ELISpot assays, respectively. Increased numbers of E7-specific IFN-gamma secreting CD8+ T cells were detected in all patients after vaccination. Swelling and induration (i.e., a positive DTH response) to the intradermal injection of HPV E7 oncoprotein and/or irradiated autologous tumor cells were detected in two patients after six vaccinations. No objective clinical responses were observed. However, both patients who developed a positive DTH to the vaccine experienced a slow tumor progression (i.e., 13 months survival) while DTH unresponsive patients died within 5 months from the beginning of therapy. CONCLUSIONS: Autologous DC pulsed with HPV16/18 E7 proteins can induce systemic B and T cell responses in patients unresponsive to standard treatment modalities. However, treatment-induced immunosuppression may impose severe limitations on the efficacy of active vaccination strategies in late stage cervical cancer patients. DC-based vaccination trials are warranted in immunocompetent cervical cancer patients with early stage disease and/or limited tumor burden, and at significant risk for tumor recurrence or disease progression.     

人乳头瘤病毒16型E7蛋白和TGF-β1/Smads信号传导通路在宫颈病变中的表达及其意义

目的:检测宫颈病变组织中人乳头瘤病毒16型(HPV-16)E7蛋白以及转化生长因子β1(TGF-β1)介导的细胞信号传导通路中TGF-β1及其Ⅱ型受体(TβRⅡ)和Smad4蛋白的表达,探讨人乳头瘤病毒感染和TGF-β1/Smads信号传导通路在肿瘤形成及演进过程中可能的作用机制。方法:免疫组织化学SP法检测141例石蜡包埋的不同病变宫颈组织中E7,TGF-β1,TβRⅡ和Smad4的表达,通过计算机图片摄像分析系统统计其在各种病变中表达水平的差异。结果:病变由良性到恶性的发展过程中,TGF-β1和Smad4的表达水平逐渐增高(P<0·001,P<0·05);肿瘤分化程度降低,TGF-β1的表达水平增高(P<0·001)。TβRⅡ表达在不同阶段和组织学类型的宫颈病变中无显著差异(P>0·05)。E7蛋白阳性者TGF-β1的表达水平较阴性者高(P<0·05),而TβRⅡ和Smad4的表达则无显著差异(P>0·05)。结论:TGF-β1在宫颈病变中的表达与病变良恶性和肿瘤分化程度有关,TGF-β1高表达是宫颈恶性肿瘤的表现之一;HPV-16感染可能影响到TGF-β1/Smads信号传导通路的功能。