HPV typing and HPV16 E6-sequence variations in synchronous lesions of cervical squamous-cell carcinoma from Swedish patients.

We microdissected 15 specimens of invasive cervical cancer co-existing with some of its precursors. Out of 15 cases, 10 carried HPV16, 2 HPV31, 1 HPV18 and 2 were HPV-negative. We found 3 HPV16 E6 variants among the 10 cases; one was A --> G in nt 131 (one case) and a second was A --> G in nt 276. The third, T;--> G in nt 350, was common, and was found in 5 of the 10 patients infected by HPV16. The type of HPV and the E6 variant were identical in all lesions within the same patient. Viral DNA present in normal epithelium was identical in type and E6 variant to HPV in the same patient's lesions. Multiple samples from invasive cancers with HPV were consistently positive. The data suggest that the originally infecting HPV, including its variant type in the E6 gene, persists unaltered in the whole series of CIN that precedes invasive cancer. Our data are compatible with an essential role of HPV manifested by persistence of the viral genome during the entire natural life history of cervical cancer. We did not confirm previous data on the specific association of invasive cancer with an HPV E6 variant (G at nt 350 rather than T). The discrepancy may depend on the relatively few cases investigated or selection of a special sub-set with progression from CIN to invasive cancer already manifest.     

HPV 16 E6 sequence variations in Indian patients with cervical neoplasia

In a cross-sectional study performed between June 2001 and November 2003, the HPV 16 E6 gene of 50 women with cervical neoplasia and 20 cytologically normal women ('controls') was sequenced following amplification by PCR. The 350T to G variant was seen in 35 (70%) of 50 patients' isolates while it was seen in only 3 (15%) of the 20 isolates from the 'controls'. The higher occurrence of the 350G variant among the patients was statistically significant (P<0.01). Isolates from patients were grouped into the European (E), Asian-American (AA) and North-American (NA-1) phylogenetic clusters with 46 (92%) belonging to the E cluster. All the 20 isolates from 'controls' belonged to the E cluster. This study suggests an association of the HPV 16 350G variant with a higher risk of cervical neoplasia and a predominance of E lineage strains among Indian HPV 16 isolates.     

宫颈癌组织中人乳头瘤病毒16E6基因突变分析

背景与目的：高危型人乳头瘤病毒（humanpa pillomavirus,HPV）以16型最为常见,HPV16E6是宫颈癌主要的致癌基因之一,特定的E6突变是宫颈癌发生的主要因素之一。本研究主要观察兰州地区宫颈癌组织中是否存在E6突变,并探讨了突变与宫颈癌发生的关系。方法：以23例宫颈癌手术切除标本及5例正常宫颈组织的DNA作为模板,PCR扩增HPV-16E6基因201-523位,PCR产物直接测序．分析其HPV16E6基因的突变规律。结果：PCR扩增结果表明5例正常宫颈组织中HPV16E6阳性率为0％（0／5）,宫颈癌组织中HPV16E6阳性率为82．61％（19／23）,对18例样本PCR产物的测序和序列分析结果表明,6例（33．33％）E6基因与原型相同,12例（66．67％）E6基因发生突变,其中11例（61．11％）发生了350G突变。同时,在1例样本（5．56％）发现了249G突变。结论：兰州地区宫颈癌组织中存在着非常高的HPV感染率,且多数HP116E6发生了突变。     

Antibodies against oncoproteins E6 and E7 of human papillomavirus types 16 and 18 in patients with head-and-neck squamous-cell carcinoma

Human papillomaviruses (HPVs) have been recognized as an essential pathogenic factor in anogenital cancer. HPV DNA has also been found in a subgroup of head-and-neck squamous-cell carcinomas (HNSCCs), and a causative role of the virus in the development of these tumors has been suggested by the concomitant inactivation of the tumor-suppressor protein pRb. Using 4 second-generation ELISAs, we found antibodies against at least 1 of the oncoproteins E6 and E7 of the high-risk HPV types 16 and 18 in 11 of 92 sera (12%) taken from HNSCC patients at or near diagnosis, in 1 of 52 sera (2%) taken from HNSCC patients >6 months after diagnosis and in 10 of 288 sera (3. 5%) taken from sex- and age-matched healthy control individuals of the normal population. In 11 of the 12 seropositive HNSCC cases, antibodies were directed against HPV16 proteins. In patients, the HPV16 antibodies were mostly of high titer, and in 6 cases, antibodies against both HPV16 oncoproteins were present. Seven of the 8 HPV16 antibody-positive sera from the control group were of low titer, and none of the 10 antibody-positive sera reacted with both oncoproteins of the same HPV type. The HPV type of the antigens detected by the antibodies in HNSCC patients correlated well with that of the HPV DNA found in the tumor. Of 19 patients known to have HPV16 DNA-positive tumors, 7 (37%) also had HPV16 E6 and/or E7 antibodies. Our finding suggests that the antibodies were formed in an immune response against HPV E6 and E7 proteins expressed in the HNSCC and thus strongly supports the concept of a biologically active role of HPV in the development of a subgroup of HNSCC.     

山东青岛地区宫颈癌组织中ＨＰＶ１６型Ｅ６和Ｅ２基因突变分析

目的　通过分析山东青岛地区宫颈组织中ＨＰＶ１６型Ｅ６和Ｅ２基因突变情况,探讨其与该地区宫颈癌的关系。方法　从１０４例青岛地区宫颈疾病组织中提取ＤＮＡ作为模板,采用聚合酶链式反应（ＰＣＲ）技术筛选出高危型ＨＰＶ及ＨＰＶ１６阳性标本,扩增出ＨＰＶ１６型Ｅ６、Ｅ２全长基因,ＰＣＲ产物纯化后测序,与德国ＨＰＶ标准株进行比对分析。结果　宫颈组织中高危型ＨＰＶ阳性率为９３.２７％（９７／１０４）,ＨＰＶ１６阳性率为６９.２３％（７２／１０４）。ＨＰＶ１６阳性标本中扩增出Ｅ６基因３７例,有５例与标准株序列相同,３２例存在突变,其中２５例突变型别为Ｔ１７８Ｇ或Ｔ１７８Ａ（Ｄ２５Ｅ）。在Ｅ２基因全序列测序中,２３例均存在Ｃ３６８４Ａ（Ｔ-Ｋ）,１４例同时存在Ｔ３５２４Ｃ、Ｃ３６８４Ａ（Ｔ-Ｋ）和Ｃ３７８７Ａ（Ｄ-Ｅ）,９例同时存在Ａ２９２６Ｇ、Ｃ３１５９Ａ（Ｔ-Ｋ）、Ｇ３２４９Ａ（Ｒ-Ｑ）、Ｔ３３８４Ｃ（Ｉ-T）、Ｃ３４１０Ｔ（Ｐ-Ｓ）和Ｃ３６８４Ａ（Ｔ-Ｋ）。结论　山东青岛地区宫颈癌患者ＨＰＶ１６型Ｅ６、Ｅ２基因与德国标准株比较存在多处变异,Ｅ６与Ｅ２基因突变可能存在相关性。     

HPV16 E6 gene variations in invasive cervical squamous cell carcinoma and cancer in situ from Russian patients

HPV16 is frequently seen in invasive cervical cancer (ICC) and cervical intraepithelial neoplasia (CIN). Its E6 gene has frequent sequence variations. Although some E6 variants have been reported to have different biochemical or biological properties, they do not show geographical identity. Moreover, the definition of 'variant' has been a source of confusion because it has been based on all departures from the 'prototype' once isolated randomly from an ICC case. We amplified the HPV16 E6 gene by PCR from fresh-frozen tissue of 104 cases of ICC and CIN from Russian patients and sequenced it in positive cases. We found that 32 of 55 (58.2%) ICC cases and 18 of 49 (36.7%) CIN cases were HPV 16-positive and we could identify 3 groups of E6 variants: group A was characterized by G at nt 350 where group B had T, and group M was a heterogeneous mixture of unique E6 variants; no significant difference existed in the distribution of the different groups between ICC and CIN; the clinically malignant (as defined by FIGO stage) order between the groups was M > A > B in ICC; in the cases with a single HPV16 E6 sequence, coexisting ICC, CIN and normal epithelium in the same patient shared the E6 variant; and 4 cases of ICC had double/multiple E6 variants. The results did not show any importance of E6 variants for ICC progression in Russian women. The results also indicated that the original HPV16 variant persisted during ICC progression, and that at a low frequency, double infections and/or mutation of variants might occur.     

Antibodies against oncoproteins E6 and E7 of human papillomavirus types 16 and 18 in cervical-carcinoma patients from Russia

Certain human papillomaviruses (HPV), mainly types 16 and 18, have been widely recognized as an essential etiologic factor for the development of carcinoma of the uterine cervix. The early HPV proteins E6 and E7 are consistently expressed in the tumor cells, and cervical-carcinoma patients can develop antibodies against these oncoproteins. For cervical-carcinoma patients from Eastern Europe and Russia, detailed information on HPV DNA prevalence and HPV-specific immune responses is limited. The presence of HPV DNA in 128 Russian cervical-carcinoma tissues was determined: HPV16 DNA was found in 78% of the cases, HPV18 DNA in 14%, and no HPV-DNA in 10%. Using 4 recently developed sensitive and highly specific second-generation enzyme-linked immunosorbent assays, we also analyzed the prevalence of antibodies against HPV16 and -18 E6 and E7 proteins in sera from 95 cervical-carcinoma patients, from 61 female patients with non-HPV-associated tumors and from 83 female healthy controls. The strong association of E6 and/or E7 antibodies with cervical carcinoma was confirmed, with 36% seropositives in this group against only 2% in the control groups. The detected antibodies are highly HPV-type-specific since all 26 HPV16-E6- or -E7-antibody-positive patients had HPV16 DNA in their tumor and 6 out of the 8 HPV18-antibody-positive patients had HPV18 DNA. Antibody responses to HPV16 E6 and E7 appear to be dependent on clinical stage of the disease, with 21% seropositives found in FIGO stage I, 42% in stage II and 53% in stage III. Antibody response to HPV16 E6 is more frequent than to E7, especially in early stages.     

A Novel Mutant of Human Papillomavirus Type 18 E6E7 Fusion Gene and its Transforming Activity

Background: Persistent human papillomavirus (HPV) infection, especially with high-risk types such as HPV16 and HPV18, has been identified as the primary cause of cervical cancer. E6 and E7 are the major onco-proteins of high-risk HPVs, which are consistently expressed in HPV infected tissues but absent in normal tissues and represent ideal therapeutic targets for immunotherapy of cervical cancer. Materials and Methods: In this study, the optimized fusion gene HPV18 E6E7 (HPV18 ofE6E7) was constructed according to genetic codon usage for human genes. At the same time, for safety future clinical application, a mutant of HPV18 ofE6E7 fusion gene was generated by site-directed mutagenesis at L52G for the E6 protein and C98G for the E7 protein. Results: HPV18-E6E7 mutant (HPV18 ofmE6E7) constructed in this work not only lost the transformation capability for NIH 3T3 cells and tumorigenicity in BALB/c nude mice, but also maintained very good stability and antigenicity. Conclusion: These results suggest that the mutant should undergo further study for application as a safe antigenspecific therapeutic vaccine for HPV18-associated tumors.     

Codon Usage Optimization and Construction of Plasmid Encoding Iranian Human Papillomavirus Type 16 E7 Oncogene for Lactococcus Lactis Subsp. Cremoris MG1363

HPV 16 intratypic sequence variations has been recognized in association with oncogenic potential diverge and geographic distribution. This study aimed to investigate nucleotide modifications and optimization of HPV 16 E7 regions from Iranian infected women. Cervical biopsies from 79/163 HPV 16 positive cancer patients detected in our study were analyzed by PCR in a couple of cloning of a complete ORF of the E7 gene, and sequencing. The most frequently observed variant was C196T in E7 which led to an amino acid change of R66W. In addition, only one common variant T234G was identified from all specimens, but it did not lead to any amino acid change. We also detected nucleotide variations A86G, and C188T in samples. Among 99 codons in E7 gene, 56 codons were improved for Lactococcus lactis subsp. cremoris MG1363 resulting in a reduced G+C content from 43.1% to 34.0%. Also, the AT%, ENC, and CAI values were 66, 20±1.1, and 1.000 instead of 56.90, 60 ±1.1, and 0.406 respectively. Finally we constructed expression vector pNZ8148 encoding optimized E7 oncoprotein of HPV 16. This study declared for the first time, the genetic variations of HPV 16 E7 in IRAN. We conclude that plasmid pNZ8148-HPV 16-opti E7 can be potential vaccine candidates in the future.     

A novel algorithm for reliable detection of human papillomavirus in paraffin embedded head and neck cancer specimen

Human papillomavirus type 16 (HPV16) plays a role in the development of a subgroup of head and neck squamous cell carcinomas (HNSCC). However, uncertainty exists about the true impact of HPV in this tumor type as conflicting reports have been published with prevalence rates from 0 to 100%. We aimed to find a detection algorithm of a biologically and thus clinically meaningful infection, applicable for high-throughput screening of frozen and formalin-fixed paraffin embedded (FFPE) specimens. By considering detection of HPV E6 oncogene expression in frozen biopsies as gold standard for a meaningful HPV infection, the value of several assays was evaluated on FFPE tumor specimens and sera of 48 HNSCC patients. The following assays were evaluated on FFPE tissue samples: HPV DNA general primer (GP)5+/6+ PCR, viral load analysis, HPV16 DNA FISH detection, HPV16 E6 mRNA RT-PCR, p16 immunostaining, and on corresponding serum samples detection of antibodies against the HPV16 proteins L1, E6 and E7. Comparing single assays on FFPE tissue samples detection of E6 expression by RT-PCR was superior, but application remains at present limited to HPV16 detection. Most suitable algorithm with 100% sensitivity and specificity appeared p16 immunostaining followed by GP5+/6+ PCR on the p16-positive cases. We show that clinically meaningful viral HPV infections can be more reliably measured in FFPE HNSCC samples in a standard and high throughput manner, paving the way for prognostic and experimental vaccination studies, regarding not only HNSCC, but possibly also cancer types with HPV involvement in subgroups such as penile and anal cancer.     

Uneven distribution of HPV 16 E6 prototype and variant (L83V) oncoprotein in cervical neoplastic lesions

A previous Swedish study revealed that both prototype and variant HPV16 E6 oncoprotein, occur in about equal numbers in high-grade cervical intraepithelial neoplasia (HCIN), whereas variant HPV16 predominates in invasive cervical squamous carcinoma. Most of the malignant HPV16 variants contain a common mutation, L83V, in the E6 oncoprotein. In the present investigation, 28 HPV16 positive, invasive cervical adenocarcinomas were collected from a total number of 131 adenocarcinomas. These HPV16-positive cases were evaluated with analysis of the E6 gene, using a recently described PCR-SSCP method for identification of the specific mutation (L83V) in the E6 gene. The results obtained were correlated to findings in 103 preinvasive, HCIN, and 31 invasive cervical squamous carcinomas also infected with HPV16. The HPV16 E6 variant L83V was present in 40% of the HCIN lesions, in 54% of the invasive adenocarcinomas, in comparison to 81% of the invasive squamous carcinomas. The difference between HCIN and squamous carcinomas was statistically significant, P < 0.001, whereas the difference between HCIN and invasive adenocarcinomas was not statistically significant, P = 0.604. Prototype HPV16 and its E6 variant L83V are both prevalent in preinvasive and invasive cervical lesions in Swedish women. However, the obvious predominance of HPV16 variant in squamous carcinomas was not seen in adenocarcinomas. A single amino-acid shift in the HPV16 E6 gene appears to result in a different transforming potential in squamous and glandular cervical lesions.     

Human papillomavirus (HPV) 16 and the prognosis of head and neck cancer in a geographical region with a low prevalence of HPV infection

Background

The role of human papillomavirus (HPV) on head and neck squamous cell carcinoma (HNSCC) survival in regions with low HPV prevalence is not yet clear. We evaluated the HPV16 infection on survival of HNSCC Brazilian patient series.

Methods

This cohort comprised 1,093 HNSCC cases recruited from 1998 to 2008 in four Brazilian cities and followed up until June 2009. HPV16 antibodies were analyzed by multiplex Luminex assay. In a subset of 398 fresh frozen or paraffin blocks of HNSCC specimens, we analyzed for HPV16 DNA by L1 generic primer polymerase chain reaction. HNSCC survival according to HPV16 antibodies was evaluated through Kaplan–Meier method and Cox regression.

Results

Prevalence of HPV16 E6 and E6/E7 antibodies was higher in oropharyngeal cancer than in other head and neck tumor sites. HPV16 DNA positive in tumor tissue was also higher in the oropharynx. Seropositivity for HPV16 E6 antibodies was correlated with improved HNSCC survival and oropharyngeal cancer. The presence of HPV16 E6/E7 antibodies was correlated with improved HNSCC survival and oropharyngeal cancer survival. The death risk of oropharyngeal squamous cell carcinoma patients HPV16 E6/E7 antibodies positive was 78 % lower than to those who test negative.

Conclusion

Oropharyngeal squamous cell carcinoma is less aggressive in the HPV16 E6/E7 positive serology patients. HPV16 E6/E7 antibody is a clinically sensible surrogate prognostic marker of oropharyngeal squamous cell carcinoma.     

Pre-clinical immunogenicity and anti-tumour efficacy of a deleted recombinant human papillomavirus type 16 E7 protein

BACKGROUND: Current vaccination strategies against Human papillomavirus (HPV)-induced ano-genital cancers mostly target E7 from HPV16. However, the oncogenic nature of E7 raises potential human safety issues. Although the modifications abrogating the E7 transforming potential have been well characterized, their effect on E7 immunogenicity has been poorly studied. In this study, we evaluated the vaccine potential of an HPV16 E7 protein deleted from the entire pRb-binding motif. MATERIALS AND METHODS: Purified recombinant deleted (E7delta21-26) and wild-type (His6-E7 and E7WT) E7 proteins were studied in pre-clinical mice models. RESULTS: In C57BL/6 mice, E7delta21-26 formulated with the Quil A adjuvant generated systemic E7-specific cytotoxic T-cell and antibody responses similar to those induced following His6-E7/Quil A and E7WT/Quil A vaccinations. E7delta21-26/Quil A injections efficiently protected animals from challenge with the HPV16-expressing tumours, C3 and TC-1. Moreover, therapeutic vaccination with adjuvant-modified E7 suppressed or significantly decreased C3 tumour outgrowth. CONCLUSION: E7delta21-26 could represent a safe and efficient vaccine candidate against E7-containing tumour cells.     

Activities of E6 Protein of Human Papillomavirus 16 Asian Variant on miR-21 Up-regulation and Expression of Human Immune Response Genes

Background: Variants of human papillomavirus (HPV) show more oncogenicity than do prototypes. TheHPV16 Asian variant (HPV16As) plays a major role in cervical cancer of Asian populations. Some amino acidchanges in the E6 protein of HPV16 variants affect E6 functions such as p53 interaction and host immunesurveillance. This study aimed to investigate activities of HPV16As E6 protein on modulation of expressionof miRNA-21 as well as interferon regulatory factors (IRFs) 1, 3, 7 and c-fos. Materials and Methods: Vectorsexpressing E6 protein of HPV16As (E6D25E) or HPV16 prototype (E6Pro) were constructed and transfected intoC33A cells. HCK1T cells expressing E6D25E or E6Pro were established by transducing retrovirus-containingE6D25E or 16E6Pro. The E6AP-binding activity of E6 and proliferation of the transfected C33A cells weredetermined. MiR-21 and mRNA of interesting genes were detected in the transfected C33A cells and/or theHCK1T cells, with or without treatment by culture medium from HeLa cells (HeLa-CM). Results: E6D25Eshowed binding activity with E6AP similar to that of E6Pro. Interestingly, E6D25E showed a higher activity ofmiR-21 induction than did E6Pro in C33A cells expressing E6 protein. This result was similar to the HCK1Tcells expressing E6 protein, with HeLa-CM treatment. The miR-21 up-regulation significantly corresponded toits target expression. Different levels of expression of IRFs were also observed in the HCK1T cells expressing E6protein. Interestingly, when treated with HeLa-CM, IRFs 1, 3 and 7 as well as c-fos were significantly suppressedin the HCK1T cells expressing E6D25E, whereas those in the HCK1T cells expressing E6Pro were induced. Asimilar situation was seen for IFN-α and IFN-β. Conclusions: E6D25E of the HPV16As variant differed fromthe E6 prototype in its activities on epigenetic modulation and immune surveillance and this might be a keyfactor for the important role of this variant in cervical cancer progression.