Cross-roads in the classification of papillomaviruses

Emerging insights into recurrent and metastatic human papillomavirus-related oropharyngeal squamous cell carcinoma

Objective

To review recent literature on human papillomavirus‐related (HPV‐positive) oropharyngeal squamous cell carcinoma (OPC) and focus on implications of recurrent and metastatic disease.

Methods

Primary articles from 1990 to 2016 indexed in MEDLINE (1) pertaining to the epidemiology of HPV‐positive OPC and (2) providing clinical insight into recurrent and metastatic OPC.

Results

The incidence of HPV‐positive OPC is increasing globally. HPV‐positive OPC is a subtype with distinct molecular and clinical features including enhanced treatment response and improved overall survival. While disease recurrence is less common in patients with HPV‐positive OPC, up to 36% of patients experience treatment failure within eight years. Recurrent and metastatic OPC has historically signified poor prognosis, however recent data are challenging this dogma. Here, we discuss recurrent and metastatic OPC in the context of HPV tumor status.

Conclusion

HPV‐positive OPC exhibits distinct genetic, cellular, epidemiological, and clinical features from HPV‐negative OPC. HPV tumor status is emerging as a marker indicative of improved prognosis after disease progression in both locoregionally recurrent and distant metastatic OPC.

Level of Evidence

N/A.

Cost-effectiveness analysis of AS04-adjuvanted human papillomavirus 16/18 vaccine compared with human papillomavirus 6/11/16/18 vaccine in the Philippines, with the new 2-dose schedule

Cervical cancer (CC) is the second leading cause of cancer death among Filipino women. Human papillomavirus (HPV) vaccination protects against CC. Two vaccines (AS04-HPV-16/18 and 4vHPV) are approved in the Philippines; they were originally developed for a 3-dose (3D) administration and have recently been approved in a 2-dose schedule (2D). This study aims to evaluate the cost-effectiveness of HPV vaccination of 13-year-old Filipino girls, in addition to current screening, in the new 2D schedule. An existing static lifetime, one-year cycle Markov cohort model was adapted to the Philippine settings to simulate the natural history of low-risk and oncogenic HPV infection, the effects of screening and vaccination of a 13-year-old girls cohort vaccinated with either the 2D-AS04-HPV-16/18 or 2D-4vHPV assuming a 100% vaccination coverage. Incremental cost, quality-adjusted life year (QALY) and cost-effectiveness were derived from these estimates. Input data were obtained from published sources and Delphi panel, using country-specific data where possible. Sensitivity analyses were performed to assess the robustness of the model. The model estimated that 2D-AS04-HPV-16/18 prevented 986 additional CC cases and 399 CC deaths (undiscounted), as well as 555 increased QALY (discounted), and save 228.1 million Philippine pesos (PHP) compared with the 2D-4vHPV. In conclusion, AS04-HPV-16/18 is shown to be dominant over 4vHPV in the Philippines, with greater estimated health benefits and lower costs.

The Papillomavirus Episteme: a major update to the papillomavirus sequence database

The Papillomavirus Episteme (PaVE) is a database of curated papillomavirus genomic sequences, accompanied by web-based sequence analysis tools. This update describes the addition of major new features. The papillomavirus genomes within PaVE have been further annotated, and now includes the major spliced mRNA transcripts. Viral genes and transcripts can be visualized on both linear and circular genome browsers. Evolutionary relationships among PaVE reference protein sequences can be analysed using multiple sequence alignments and phylogenetic trees. To assist in viral discovery, PaVE offers a typing tool; a simplified algorithm to determine whether a newly sequenced virus is novel. PaVE also now contains an image library containing gross clinical and histopathological images of papillomavirus infected lesions. Database URL: https://pave.niaid.nih.gov/.

HPV in Head and Neck Cancer-30 Years of History

The interesting history of papillomavirus (PV) research has been reviewed before. The history of human papillomavirus (HPV) in head and neck region starts in 1901 when the contagious transmission of warty lesions into the mouth via oral sex was described, although the confirmation of their viral etiology had to wait until 1907. Ullman was the first to associate the human wart virus with laryngeal warts. Parsons and Kidd described the natural history of oral PV infections in rabbits already in 1942, but these findings were corroborated in humans only recently. Koilocytotic atypia described by Koss and Durfee in 1956 was recognized as a sign of HPV infection in cervical precancer lesions only in 1976-1977 (Meisels and Fortin; Purola and Savia). This prompted systematic surveys of head and neck lesions for the detection of koilocytosis since the late 1970s, and the authors of this communication were the first to propose the HPV involvement in a subgroup of head and neck cancers. Brandsma and Abramson demonstrated HPV16 DNA in tonsillar SCCs in 1989. Since the early 2000s, HPV research of head and neck squamous cell carcinomas (HNSCC) has made impressive progress, confirming that the specific anatomic site plays a key role in determining the susceptibility to HPV infection. The most likely cancer sites associated with HPV are the base of the tongue and palatine tonsils, followed by oral cavity, larynx, and sinonasal mucosa. There is substantial geographic variation in HPV association with HNSCC. Patients with HPV-associated HNSCC are younger, and survival is better than in the absence of HPV.

Anal human papillomavirus infection: prevalence, diagnosis and treatment of related lesions

Human papillomavirus (HPV) infection is mostly asymptomatic, but may also have many diverse clinical signs encompassing benign ano-genital lesions, and carcinomas. Recently, interest has also particularly focused on anal cancer since, over the last decades, its incidence has been greatly increasing in developed countries, both in women and men and is drastically higher in specific risk groups, such as men who have sex with men (MSM) and HIV-1 infected individuals. Approximately 88% of anal cancer cases worldwide are associated with HPV infection. This review summarizes our current understanding of anal HPV infection, discussing its epidemiology and risk factors in various populations, and the state of the art in the detection of anal HPV infection and its related lesions through both cytology and histology. Finally, we discuss the clinical management and therapy for these lesions.

A naturally occurring variant of HPV-16 E7 exerts increased transforming activity through acquisition of an additional phospho-acceptor site

Human Papillomavirus E6 and E7 play critical roles in cancer development, although not all isolates of the viral oncoproteins are identical. A common E7 variant encodes an amino acid change at N29S. We show that this change increases the levels of phosphorylation by CKII by creating an additional phospho-acceptor site at S29. This confers increased phospho-dependent interaction with a number of cellular targets, including TATA Box Binding Protein (TBP) and pRb. A further consequence is an increased ability to target pRb and p130 for degradation. Biologically, these biochemical differences are reflected in an increased ability of the N29S variant to transform primary rodent cells. This is the first study to demonstrate an important biochemical change in E7 function caused by a naturally occurring variation, and we suggest that the N29S variant merits further assessment to determine whether it has an increased association with the development of HPV-associated malignancies.

Lipidated L2 epitope repeats fused with a single-chain antibody fragment targeting human FcγRI elicited cross-neutralizing antibodies against a broad spectrum of human papillomavirus types

Numerous types of human papillomaviruses (HPVs) have been identified, and the global burden of diseases associated with HPV infection is remarkable, especially in developing regions. Thus a low-cost broad-spectrum prophylactic vaccine is urgently needed. The N-terminal amino acid 17-36 of HPV 16 L2 protein is confirmed to be a major cross-neutralizing epitope (RG-1 epitope). Monomeric proteins containing RG-1 epitopes and scaffold proteins, such as bacterial thioredoxin or modified IgG1 Fc fragment and L2 epitope fusion protein, induced cross-neutralizing antibodies, arousing the possibility of the development of low-cost monomeric vaccine in bacterial expression system. Here we show that a novel immunogen-scaffold protein containing a lipidated triple-repeat HPV 16RG-1 epitope and a hFcγRI specific single-chain antibody fragment (H22scFv), named LpE3H22, elicited high titers of cross-neutralizing antibodies against a broad range of mucosal and cutaneous HPV types when adjuvanted with MF59 and poly I:C. LpE3H22 was produced in E. coli expression system. In contrast to three repeats of RG-1 epitope (E3) and unlipidated fusion protein E3H22, vaccination of LpE3H22 induced robust cross-neutralizing antibody responses in hFcγRI transgenic mice. Furthermore, the neutralizing antibody response induced by LpE3H22 was significantly weaker in WT mice than in the Tg mice. The cross-neutralizing antibodies induced by LpE3H22 sustained for at least 10months in Tg mice. Our results demonstrate that hFcγRI targeting and lipidation both contribute to the enhancement of immunogenicity of L2 antigen. Therefore, delivering the lipidated L2 antigen with H22scFv opens a new avenue for low-cost pan-HPV vaccine development.

[Molecular diagnosis of human papillomaviruses (HPV): What test(s) in clinical practice?]

Prescription of an HPV test in practice will enable the clinician to optimize the monitoring and the management of patients, especially in the context of cervical cancer screening. Numerous HPV tests are available that present different analytical and clinical sensitivity and specificity. International recommendations on clinical performance of HPV tests used for cervical cancer screening have been published by a group of experts, and tests that meet these performance criteria should be used. Apart from the HPV detection kit, the whole circuit from sampling to report of the results must be considered. This implies that the pre-analytical (sampling, quality of sample collection medium, storage condition and sample transportation…) and post-analytical steps (quality of result reporting, providing expert advices…) are also standardized. For this purpose, medical-biology laboratories are subjected to a COFRAC certification, as defined by the international standard ISO 15189 providing quality criteria for any clinical laboratory test and HPV test in particular.

Population-based study for human papillomavirus (HPV) infection in young women in Japan: A multicenter study by the Japanese human papillomavirus disease education research survey group (J-HERS)

A multi-center study was conducted to examine 6,628 eligible Japanese women aged from 16 to 50 years for uterine cervical abnormality and HPV infection with a liquid based-cytology test and a novel HPV test using the PCR-SSOP-Luminex(®) method identifying 31 HPV genotypes. In 3,047 normal subjects, the overall prevalence across all HPV types was 25%, while that of the common 13 high-risk (Common-13HR) types (HPV-16, 18. 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, and 68) was 17%, and that of the definite high-risk (Definite-HR) types (HPV-16, 18. 31, 33, 35, 45, 52, and 58) was 12%. For Definite-HR, HPV-52, 16, and 58 were the most common, HPV-31 was relatively common, and HPV-18 was less common, while HPV-33, 35, and 45 were rare. Seven Definite-HR excluding HPV-45 and seven Possible-HR (HPV-39, 51, 56, 66, 68, 70, and 82) HPV types were identified as a single type infection in patients with high-grade squamous intraepithelial lesion (HSIL) or worse. The Common-13HR types were detected in 89% of subjects with HSIL, whereas either Definite-HR or Possible-HR types were detected in 95% of HSIL. These 1420 HPV types appear to be involved with HSIL or worse in Japan. The prevalences of multiple-type HPV infections were identified in roughly half of HPV-positive subjects, and decreased significantly with age in normal population and abnormal cytology groups, although the prevalences of single-type infections increased with age in the latter group. Most HPV infections are cleared for some years, while a certain HR-HPV type persists to induce HSIL.

The Biological Impact of Genomic Diversity in Cervical Cancer Development

Human papillomaviruses (HPVs) are the etiologic agents of cervical cancer, the unique human neoplasia that has one single necessary cause. The diversity of HPVs is well described, with 200 HPV types existing as distinct taxonomic units and each receiving an Arabic number. On a clinical basis, they are usually grouped by their site of occurrence and disease associations. Those types inhabiting the anogenital mucosa are more intensively studied and further divided into cancer-associated HPVs, which are termed 'high risk', while those linked to benign proliferative lesions are assigned as 'low risk'. HPV16 is responsible for approximately 50% of all ICC cases, and paradoxically is one of the most prevalent types among healthy women. Longitudinal studies have shown that when an incidental HPV16 infection becomes persistent it will result in an enhanced risk for the development of high-grade lesions. However, it is unknown why some persistent, HPV16 infections (or infections by other HR-HPV types) progress to CIN3+ while most clear spontaneously. Several epidemiological investigations have focused on cofactors, from the most obvious such as cigarette and other carcinogenic exposures, to coinfections by other STDs such as chlamydia, with no significant findings. Thus, the current focus is on genomic variation from both virus and host. Such studies have been potentialized by the enormous technical advances in nucleic acid sequencing, allowing this relationship to be broadly interrogated. Corroborating subgenomic data from decades ago, an association between HPV16 lineages and carcinogenesis is being revealed. However, this effect does not seem to apply across female populations from different continents/ethnicities, again highlighting a role played by HPV16 adaptation and evasion from the host over time.

Design of peptides as inhibitors of human papillomavirus 16 transcriptional regulator E1-E2

Human papillomavirus 16 (HPV 16) is a DNA virus that is capable of infecting humans and causing cervical cancer. HPV16 E2 plays an important role in viral gene regulation. This work aims to predict the binding conformations and interactions between the dodecapeptides and HPV16 E2 as well as to design novel peptide inhibitors that are capable of binding to HPV16 E2 and disrupt the transcriptional regulator E1-E2 complex formation, using computational protein design techniques. Based on previously reported peptide4 (TWFWPYPYPHLP), novel peptide inhibitors were designed and five peptides that showed lower binding energy to HPV16 E2 than that of peptide4, were selected for in vitro experiments. Enzyme-linked immunosorbent (ELISA) assay showed that Y6R, W4H_Y6R, and W4H peptides bound to HPV16 E2 with higher affinity than peptide4 did. Moreover, Y6R, W4H_Y6R, and W4H peptides more effectively inhibited E1-E2 complex formation than peptide4. This work revealed important interactions between the peptides and E1-E2 complex, suggesting a strategy for development of more potent peptide inhibitors.

Novel Bovine Papillomavirus Type Discovered by Rolling-Circle Amplification Coupled with Next-Generation Sequencing

Currently, fifteen bovine papillomavirus (BPV) types have been identified and classified into four genera: Deltapapillomavirus, Epsilonpapillomavirus, Dyoxipapillomavirus, and Xipapillomavirus. Here, the complete genome sequence of a new BPV type (BPV 04AC14) recovered from a papillomatous lesion is reported. The genome is 7,282 bp in length and exhibits the classic genetic organization and motifs of the members of Papillomaviridae. Maximum likelihood phylogenetic analyses revealed that BPV 04AC14 clusters with members of the Xipapillomavirus genus. The nucleotide sequence of the L1 capsid protein of the novel BPV is closely related to its counterpart, BPV3, with which it shares 79% similarity. These findings suggest that this virus is a new BPV type of the Xipapillomavirus genus.

HPV disease transmission protection and control

Human papillomaviruses (HPVs) represent a large collection of viral types associated with significant clinical disease of cutaneous and mucosal epithelium. HPV-associated cancers are found in anogenital and oral mucosa, and at various cutaneous sites. Papillomaviruses are highly species and tissue restricted, and these viruses display both mucosotropic, cutaneotropic or dual tropism for epithelial tissues. A subset of HPV types, predominantly mucosal, are also oncogenic and cancers with these HPV types account for more than 200,000 deaths world-wide. Host control of HPV infections requires both innate and adaptive immunity, but the viruses have developed strategies to escape immune detection. Viral proteins can disrupt both innate pathogen-sensing pathways and T-cell based recognition and subsequent destruction of infected tissues. Current treatments to manage HPV infections include mostly ablative strategies in which recurrences are common and only active disease is treated. Although much is known about the papillomavirus life cycle, viral protein functions, and immune responsiveness, we still lack knowledge in a number of key areas of PV biology including tissue tropism, site-specific cancer progression, codon usage profiles, and what are the best strategies to mount an effective immune response to the carcinogenic stages of PV disease. In this review, disease transmission, protection and control are discussed together with questions related to areas in PV biology that will continue to provide productive opportunities of discovery and to further our understanding of this diverse set of human viral pathogens.

Geno- and seroprevalence of Felis domesticus Papillomavirus type 2 (FdPV2) in dermatologically healthy cats

Background

Papillomaviruses can cause proliferative skin lesions ranging from benign hyperplasia to squamous cell carcinoma (SCC). However, asymptomatic infection is also possible. Several groups have detected Felis domesticus Papillomavirus type 2 (FdPV2) DNA in association with feline Bowenoid in situ carcinoma (BISC). Therefore, a causative connection has been suggested. However, the knowledge about FdPV2 epidemiology is limited. The aim of this study was to describe the genoprevalence and seroprevalence of FdPV2 in healthy cats.

For this purpose an FdPV2-specific quantitative (q)PCR assay was developed and used to analyse Cytobrush samples collected from 100 dermatologically healthy cats. Moreover, an ELISA was established to test the sera obtained from the same cats for antibodies against the major capsid protein (L1) of FdPV2.

Results

The genoprevalence of FdPV2 was to 98 %. Surprisingly, the quantities of viral DNA detected in some samples from the healthy cats exceeded the amounts detected in control samples from feline BISC lesions. The seroprevalence was much lower, amounting to 22 %. The concentrations of antibodies against FdPV2 were relatively low in healthy cats, whereas they were very high in control cats with BISC.

Conclusion

These observations suggest that FdPV2 is highly prevalent, even among healthy cats. However, cats that carry it on their skin mount in most instances no antibody response. It might be hypothesized that FdPV2 is only rarely productively replicating or its replication is only rarely exposed to the immune system.

Electronic supplementary material

The online version of this article (doi:10.1186/s12917-016-0776-7) contains supplementary material, which is available to authorized users.

Quantitative and epitope-specific antigenicity analysis of the human papillomavirus 6 capsid protein in aqueous solution or when adsorbed on particulate adjuvants

Human papillomavirus (HPV) 6 is a human pathogen which causes genital warts. Recombinant virus-like particle (VLP) based antigens are the active components in prophylactic vaccines to elicit functional antibodies. The binding and functional characteristics of a panel of 15 murine monoclonal antibodies (mAbs) against HPV6 was quantitatively assessed. Elite conformational indicators, recognizing the conformational epitopes, are also elite viral neutralizers as demonstrated with their viral neutralization efficiency (5 mAbs with neutralization titer below 4ng/mL) in a pseudovirion (PsV)-based system. The functionality of a given mAb is closely related to the nature of the corresponding epitope, rather than the apparent binding affinity to antigen. The epitope-specific antigenicity assays can be used to assess the binding activity of PsV or VLP preparations to neutralizing mAbs. These mAb-based assays can be used for process monitoring and for product release and characterization to confirm the existence of functional epitopes in purified antigen preparations. Due to the particulate nature of the alum adjuvants, the vaccine antigen adsorbed on adjuvants was considered largely as "a black box" due to the difficulty in analysis and visualization. Here, a novel method with fluorescence-based high content imaging for visualization and quantitating the immunoreactivity of adjuvant-adsorbed VLPs with neutralizing mAbs was developed, in which antigen desorption was not needed. The facile and quantitative in situ antigenicity analysis was amendable for automation. The integrity of a given epitope or two non-overlapping epitopes on the recombinant VLPs in their adjuvanted form can be assessed in a quantitative manner for cross-lot or cross-product comparative analysis with minimal manipulation of samples.

Comparison of initial stream urine samples and cervical samples for detection of human papillomavirus

BACKGROUND

Uterine cervical cancer is a treatable and preventable cancer. Medical efforts to reduce rates of cervical cancer focus on the promotion of human papillomavirus (HPV) vaccination and the promotion of routine cervical cancer screening done by cervical cytology and cervical HPV testing. Urine-based HPV testing would be simple and noninvasive approach to screen for cervical cancer.

METHODS

Two biospecimens (clinician-taken sample from cervix and initial stream urine sample) were provided from a total of 240 healthy women attending for cancer screening provided for HPV testing. We have assessed the HPV detection rates among cervical samples and pellet fraction of urine samples using HPV test (Anyplex™ II HPV28 Detection kit, Seegene, Korea).

RESULTS

Among 240 samples screened, HPV prevalence was 42.9% in pellet fractions of urine samples. The agreement between the two kinds of samples was 98.4%, k = 0.792. Discordant results were observed in 27 cases; 5 were positive only by urine samples and 22 were positive only by smear samples. Sensitivity and specificity for all HPV DNA in pellet fractions of urine using cervical samples as reference was 68.4% and 99.9%.

CONCLUSIONS

Comparing methodologies of collection of samples for HPV detection, they showed the higher agreements for almost genotypes between cervical samples and pellet fractions of urine samples. These results suggest that urine could be a good noninvasive tool to monitor HPV infection in women. Additional research in a larger and general screening population would be needed.

Shift in prevalence of HPV types in cervical cytology specimens in the era of HPV vaccination

The aim of the present population-based cohort study was to analyze the association between the prevalence of 32 types of human papilloma virus (HPV) in 615 female patients with abnormal cervical cytopathology findings. In total, 32 HPV types were screened by DNA array technology. HPV infection was detected in 470 women (76.42%), 419 of whom (89.15%) were infected with ≥1 high-risk (HR)-HPV type. HPV16, which is recognized as the main HR-HPV type responsible for the development of cervical cancer, was observed in 32.98% of HPV⁺ participants, followed by HPV42 (18.09%), HPV31 (17.66%), HPV51 (13.83%), HPV56 (10.00%), HPV53 (8.72%) and HPV66 (8.72%). The prevalence of HR-HPV types, which may be suppressed directly (in the case of HPV16 and 18), or possibly via cross-protection (in the case of HPV31) following vaccination, was considerably lower in participants ≤22 years of age (HPV16, 28.57%; HPV18, 2.04%; HPV31, 6.12%), compared with participants 23-29 years of age (HPV16, 45.71%; HPV18, 7.86%; HPV31, 22.86%), who were less likely to be vaccinated. Consequently, the present study hypothesizes that there may be a continuous shift in the prevalence of HPV types as a result of vaccination. Furthermore, the percentage of non-vaccine HR-HPV types was higher than expected, considering that eight HPV types formerly classified as 'low-risk' or 'probably high-risk' are in fact HR-HPV types. Therefore, it may be important to monitor non-vaccine HPV types in future studies, and an investigation concerning several HR-HPV types as risk factors for the development of cervical cancer is required.

Preventing cervical cancer and genital warts - How much protection is enough for HPV vaccines?

HPV associated disease is a global health problem: 5.2% of all cancers are HPV associated with HPV 16 and 18 accounting for 70% of cases of cervical cancer. Genital warts caused by HPV 6 and 11 have a lifetime risk of acquisition of 10%. HPV vaccines are subunit vaccines consisting of virus like particles comprised of the L1 major capsid protein. Two vaccines have been licenced since 2006/2007 and are in the National Immunisation programmes in 62 countries. Both vaccines include HPV 16 and 18 VLPs and one also includes HPV 6 and 11. The vaccines are highly immunogenic and well tolerated. Genital HPV is a sexually transmitted infection with peak incidence occurring just after the onset of sexual activity and the routine cohort for immunisation in almost all countries are adolescent girls 9-15 years of age with or without catch up for older adolescents and young women. Population effectiveness is now being demonstrated for these vaccines in countries with high vaccine coverage. HPV vaccines are highly immunogenic and effective and the original 3 dose schedules have already been reduced, for those 14 years and under, to 2 for both licenced vaccines. There is preliminary evidence that 1 dose of vaccine is as effective as 2 or 3 in preventing persistent HPV infection in the cervix in young women and further reductions in dosage may be possible if supported by appropriate virological, immunological and modelling studies.

Variant-specific persistence of infections with human papillomavirus Types 31, 33, 45, 56 and 58 and risk of cervical intraepithelial neoplasia

In our previous study of the etiologic role of oncogenic human papillomavirus (HPV) types other than HPV16 and 18, we observed a significantly higher risk of cervical intraepithelial neoplasia Grades 2-3 (CIN2/3) associated with certain lineages of HPV types 31/33/45/56/58 [called high-risk (HR) variants] compared with non-HR variants. This study was to examine whether these intra-type variants differ in persistence of the infection and persistence-associated risk of CIN2/3. Study subjects were women who had any of HPV types 31/33/45/56/58 newly detected during a 2-year follow-up with 6-month intervals. For each type, the first positive sample was used for variant characterization. The association of reverting-to-negativity with group of the variants and CIN2/3 with length of positivity was assessed using discrete Cox regression and logistic regression, respectively. Of the 598 newly detected, type-specific HPV infections, 312 became undetectable during follow-up. Infections with HR, compared with non-HR, variants were marginally more likely to become negative [adjusted hazard ratio = 1.3; 95% confidence interval (CI), 0.9-1.8]. The adjusted odds ratio associating with the development of CIN2/3 was 3.0 (95% CI, 1.2-7.4) for persistent infections with HR variants for 6 months and 10.0 (95% CI, 3.8-38.0) for persistent infections with HR variants for 12-18 months as compared with the first positive detection of HR variants. Among women with non-HR variants, there were no appreciable differences in risk of CIN2/3 by length of positivity. Findings suggest that the lineage-associated risk of CIN2/3 was not mediated through a prolonged persistent infection, but oncogenic heterogeneity of the variants.

Role of Cdc6 in re-replication in cells expressing human papillomavirus E7 oncogene

The E7 oncoprotein of high-risk human papillomavirus (HPV) types induces DNA re-replication that contributes to carcinogenesis; however, the mechanism is not fully understood. To better understand the mechanism by which E7 induces re-replication, we investigated the expression and function of cell division cycle 6 (Cdc6) in E7-expressing cells. Cdc6 is a DNA replication initiation factor and exhibits oncogenic activities when overexpressed. We found that in E7-expressing cells, the steady-state level of Cdc6 protein was upregulated and its half-life was increased. Cdc6 was localized to the nucleus and associated with chromatin, especially upon DNA damage. Importantly, downregulation of Cdc6 reduced E7-induced re-replication. Interestingly, the level of Cdc6 phosphorylation at serine 54 (S54P) was increased in E7-expressing cells. S54P was associated with an increase in the total amount of Cdc6 and chromatin-bound Cdc6. DNA damage-enhanced upregulation and chromatin binding of Cdc6 appeared to be due to downregulation of cyclin-dependent kinase 1 (Cdk1) as Cdk1 knockdown increased Cdc6 levels. Furthermore, Cdk1 knockdown or inhibition led to re-replication. These findings shed light on the mechanism by which HPV induces genomic instability and may help identify potential targets for drug development.

Characterization of novel human papillomavirus types 157, 158 and 205 from healthy skin and recombination analysis in genus γ-Papillomavirus

Gammapapillomavirus (γ-PV) is a diverse and rapidly expanding genus, currently consisting of 79 fully characterized human PV (HPV) types. In this study, three novel types, HPV157, HPV158 and HPV205, obtained from healthy sun-exposed skin of two immunocompetent individuals, were amplified by the "Hanging droplet" long PCR technique, cloned, sequenced and characterized. HPV157, HPV158 and HPV205 genomes comprise 7154-bp, 7192-bp and 7298-bp, respectively, and contain four early (E1, E2, E6 and E7) and two late genes (L1 and L2). Phylogenetic analysis of the L1 ORF placed all novel types within the γ-PV genus: HPV157 was classified as a new member of species γ-12 while HPV158 and HPV205 belong to species γ-1. We then explored potential recombination events in genus γ-PV with the RDP4 program in a dataset of 74 viruses (71 HPV types with available full-length genomes and the 3 novel types). Two events, both located in the E1 ORF, met the inclusion criterion (p-values <0.05 with at least four methods) and persisted in different ORF combinations: an inter-species recombination in species γ-8 (major and minor parents: species γ-24 and γ-11, respectively), and an intra-species recombination in species γ-7 (recombinant strain: HPV170; major and minor parents: HPV-109 and HPV-149, respectively). These findings were confirmed by phylogenetic tree incongruence analysis. An additional incongruence was found in members of species γ-9 but it was not detected by the RDP4. This report expands our knowledge of the family Papillomaviridae and provides for the first time in silico evidence of recombination in genus γ-PV.

[HPV DNA genotyping: A study of anogenital, head and neck and skin cancers in a population from west Algerian. HPV detection in different cancers from an Algerian population]

OBJECTIVES

To investigate the prevalence of human papillomaviruses (HPV) in cancers located at different sites in patients from west Algerian and collected between 2010 and 2014.

MATERIAL AND METHODS

Extracted DNA from archival formaldehyde-fixed and paraffin-embedded tissues was provided from 39 anogenital cancers, 10 head and neck cancers and 36 skin cancers. The viral DNA was detected using the INNO-LiPA HPV Genotyping Extra(®) kit.

RESULTS

The prevalence of HPV was 100% in cervical cancers, 40% in vaginal cancers, 17% in vulvar cancers, 33% in anal cancers, 0% in tonsil and larynx cancers and 6.4% in skin squamous cell carcinoma. In cervical cancers, the most prevalent genotypes were HPV16 (52%) and HPV18 (12%) as single infection.

CONCLUSION

The overall results agree partially with literature. Extensive research is necessary to promote HPV vaccine to reduce in particular the burden of cervical cancer in Algeria.

Sociodemographic characteristics and sexual behavior as risk factors for human papillomavirus infection in Saudi Arabia

OBJECTIVES

To determine the prevalence and the sociodemographic characteristics and sexual behavior risk factors for human papillomavirus (HPV) infection in a hospital-based cohort of women in Saudi Arabia.

METHODS

Cervical specimens and questionnaire data were collected from women attending clinics in Riyadh, Saudi Arabia. Cervical specimens were examined for abnormal cytology using a standard Pap test and for the presence of HPV-DNA using PCR and reverse line blot hybridization tests.

RESULTS

Approximately 73% of the 400 women tested were Saudi nationals. Nearly 50% were under 40 years old (range 22-80 years, mean±standard deviation 41.20±10.43 years). Approximately 17% of the women were HPV-positive. The most commonly detected HPV types were HPV-18 (34%) and HPV-16 (19%), with multiple infections detected in 10% of positive specimens. Multivariate analyses revealed that smoking and multiple partners were significant risk factors for HPV infection (p<0.01).

CONCLUSIONS

Because of societal challenges and an unsubstantiated assumption of low HPV prevalence, few studies have examined sociodemographic characteristics or sexual behaviors associated with HPV in Saudi women. However, a high prevalence of HPV infection was found, with smoking and multiple partners as significant risk factors, in this hospital-based cohort of predominantly Saudi women.

HPV vaccines: how many doses are needed for protection?

HPV virus-like particle vaccines are highly immunogenic, well tolerated and are in the national immunization programs in more than 62 countries. Genital HPV is a sexually transmitted infection with first infection occurring just after the onset of sexual activity. The routine cohort for immunization in almost all countries are adolescent girls 9–15 years of age with or without catch-up for older adolescents and young women. In countries with vaccine coverage exceeding 50%, reductions in vaccine type HPV geno-prevalence and disease are being shown. The mechanism of protection is assumed to be via neutralizing antibody. Antibody concentration in adolescents less than 14 years of age after two doses of vaccine at 0 and 6 months are noninferior to women after three doses and in whom efficacy was demonstrated in randomized control trials. The original three-dose schedules have already been reduced in many countries, for those 14 years of age and under, to two doses at least 6 months apart for the licensed vaccines Cervarix® and GARDASIL®. There is preliminary evidence that one dose of vaccine is as effective as two or three doses at preventing persistent HPV infection in the cervix in young women and a one-dose schedule may be possible if supported by evidence from randomized controlled trials.

Gardasil-9: A global survey of projected efficacy

Human papillomaviruses (HPVs) are the causative agents of human neoplasias such as warts and cancers. There are ∼19 HPV types associated with cancers, which has made it very challenging for first generation HPV vaccines to offer complete protection against all cancer-causing HPV types. Recently, a second generation HPV vaccine, Gardasil-9, has been approved to protect against more HPV types. Worldwide, Gardasil-9 will protect against HPV types associated with ∼90% of cervical cancer case in women and 80-95% of other HPV-associated anogenital cancers in both men and women. However, due to variation in HPV-type specific prevalence and distribution, the vaccine will offer different percentages of protection in different geographical regions; Gardasil-9 will offer protection against HPV types associated with ∼87.7% of cervical cancers in Asia, 91.7% in Africa, 92% in North America, 90.9% in Europe, 89.5% in Latin America & the Caribbean, and 86.5% in Australia. Because of this, Pap smear screening and testing for HPV types not included in Gardasil-9 will need to continue, especially in HIV/AIDS patients. In order to achieve complete protection against all HPV types that cause cervical cancer, a third-generation HPV vaccine is needed.

Human Papillomavirus Laboratory Testing: the Changing Paradigm

High-risk human papillomaviruses (HPVs) cause essentially all cervical cancers, most anal and oropharyngeal cancers, and some vaginal, vulvar, and penile cancers. Improved understanding of the pathogenesis of infection and the availability of newer tests are changing the approach to screening and diagnosis. Molecular tests to detect DNA from the most common high-risk HPVs are FDA approved for use in conjunction with cytology in cervical cancer screening programs. More-specific tests that detect RNA from high-risk HPV types are now also available. The use of molecular tests as the primary screening tests is being adopted in some areas. Genotyping to identify HPV16 and -18 has a recommended role in triaging patients for colposcopy who are high-risk HPV positive but have normal cytology. There are currently no recommended screening methods for anal, vulvar, vaginal, penile, or oropharyngeal HPV infections. HPV testing has limited utility in patients at high risk for anal cancer, but p16 immunohistochemistry is recommended to clarify lesions in tissue biopsy specimens that show moderate dysplasia or precancer mimics. HPV testing is recommended for oropharyngeal squamous cell tumors as a prognostic indicator. Ongoing research will help to improve the content of future guidelines for screening and diagnostic testing.

Inflammatory microenvironment and human papillomavirus-induced carcinogenesis

More than 15% of the global cancer burden is attributable to infectious agents. Pathogens that cause persistent infections are strongly associated with cancer, inflammation being a major component of the chronic infections as revealed by basic, clinical and epidemiological studies. Persistent infection and viral oncoproteins induce specific cellular pathways modifications that promote tumorigenesis. Deregulated and continuous immune response leads to severe tissue and systemic damage, impaired tumor surveillance and consequent carcinogenesis promotion by selecting for metastatic and therapeutically resistant tumor phenotypes. In this review, the role of inflammatory microenvironment in the HPV-induced carcinogenesis is addressed, with a specific focus on the involvement of the immune molecules and microRNAs as well as their delivery through the microvesicle cargo.

The Association Between Cervical Human Papillomavirus Infection and Subsequent HIV Acquisition in Tanzanian and Ugandan Women: A Nested Case-Control Study

OBJECTIVE

This study was performed to analyze the associations between cervical human papillomavirus (HPV) infection and human immunodeficiency virus (HIV) acquisition, using cervical samples from previous studies in Tanzania and Uganda.

METHODS

A total of 161 adult women who acquired HIV infection during follow-up and 464 individually matched HIV-seronegative controls were selected from 5 cohorts of women working in bars and recreational facilities. Stored cervical samples were tested for 37 HPV genotypes, using a polymerase chain reaction assay (Roche Linear Array genotyping assay). Multivariate matched analysis using conditional logistic regression was performed to evaluate HPV infection, persistence, and clearance as predictors of HIV acquisition.

RESULTS

HIV seroconverters were significantly more likely than controls to frequently drink alcohol and to be infected with Chlamydia trachomatis, Neisseria gonorrhoeae, or herpes simplex virus type 2. There was no evidence of an association between HIV acquisition and any detectable HPV at the visit prior to HIV seroconversion (adjusted odds ratio, 1.02; 95% confidence interval, .66-1.57) or between HIV acquisition and persistent HPV infection (defined as 2 positive HPV genotype-specific test results at least 6 months apart), cleared HPV infection (defined as a positive HPV test result followed by negative HPV genotype-specific test result), or newly acquired HPV infection, compared with HPV-negative women.

CONCLUSIONS

There was no evidence of association between HPV infection status and subsequent HIV acquisition. These results stand in contrast to other observational studies.

Prevalence and Associated Risk Factors of Human Papillomavirus in Healthy Skin Specimens Collected from Rural Anyang, China, 2006-2008

Skin infections with cutaneous human papillomavirus (HPV) have been linked to the development of non-melanoma skin cancer, in which mucosal HPV may also play a crucial role. However, systematic investigations of the distribution and associated factors of HPV infection in healthy skin of the general population are scarce. HPV DNA from palmar exfoliated cells of 2,087 individuals was detected by FAP6085/64 and SPF1/GP6+ primers followed by sequencing. A total of 338 papillomavirus types were detected, with HPV-3, HPV-57, and HPV-49 being the most dominant types. The overall prevalence for HPV DNA on skin was 79.92% and for alpha-, beta-, and gamma-HPV were 27.07%, 38.76%, and 29.56%, respectively. Having multiple lifetime sexual partners (adjusted odds ratio 1.60), being a migrant worker (adjusted odds ratio 2.05, reference: farmers), and frequent bathing (Ptrend = 0.001) were associated with alpha-HPV DNA presence. Advancing age increased the detection risk of beta-HPV (Ptrend = 0.001). Higher education (Ptrend = 0.017) and frequent bathing (Ptrend = 0.001) were positively related to gamma-HPV positivity. This study demonstrates that alpha-HPV commonly exists on healthy skin of the general population in rural China, and alpha- and gamma-HPV infections are related to certain behaviors, different from beta-HPV infection. These findings are crucial to better understanding the biology of HPV infection and may be suggestive of the potential transmission of these viruses.

An Evaluation of the Cobas4800 HPV Test on Cervico-Vaginal Specimens in Liquid versus Solid Transport Media

Objectives

Determine the ability of the Cobas 4800 assay to detect high-risk human papillomavirus (HrHPV) and high-grade cervical lesions when using cervico-vaginal samples applied to liquid medium and solid media cards compared to a direct cervical sample.

Methods

Two cervico-vaginal specimens (pseudo self-collected) were obtained from 319 women. One was applied to an iFTA Card (FTA) then the brush placed in liquid-based medium (LSELF); the other was applied to a new solid media: POI card (POI). The clinical performance of Cobas4800 assay using the three aforementioned specimens was compared to direct collected endocervical specimens in liquid media (LDOC).

Results

The overall agreements of HrHPV detection were 84.2% (LSELF vs. LDOC), 81.0% (FTA vs. LDOC), and 82.3% (POI vs. LDOC). LSELF, FTA and POI identified 98.0%, 79.6%, and 97.5% positive cases of LDOC. Sensitivity to identify CIN2+ were 98.4% (LSELF), 73.8% (FTA), 95.1% (POI), and 93.4% (LDOC) respectively. FTA had 78.1% and 90.4% agreement with the LSELF samples for all HrHPV and HPV16/18 detection respectively, while POI had 91.6% for both.

Conclusions

Cobas4800 HPV test combined with cervico-vaginal specimens applied to both liquid media and POI solid card are accurate to detect HrHPV infection and high-grade cervical lesions as compared with direct endocervical samples in liquid media.

Detection of Human Papillomavirus Infections at the Single-Cell Level

OBJECTIVE

To explore the possibility of single-cell analysis of human papillomavirus (HPV) infection.

METHODS

Two hundred and twenty cells were isolated by laser capture microdissection from formalin-fixed and paraffin-embedded cervical tissue blocks from 8 women who had HPV DNA detected in their cervical swab samples. The number of type-specific HPV copies in individual cells was measured by quantitative polymerase chain reaction with and without a prior reverse transcription. The cells were assayed and counted for more than once if the corresponding swab sample was positive for ≥2 HPV types.

RESULTS

Infection with HPV16, HPV39, HPV51, HPV52, HPV58, HPV59 and HPV73 was detected in 12 (5.5%) of 220, 3 (9.4%) of 32, 3 (5.8%) of 52, 11 (22.9%) of 48, 9 (18.8%) of 48, 3 (9.4%) of 32 and none of 20 cells, respectively. The numbers of HPV genome copies varied widely from cell to cell. The coexistence of multiple HPV types was detected in 6 (31.6%) of 19 positive cells from 1 of the 6 women who had 2 or 3 HPV types detected in their swab samples.

CONCLUSION

Given the heterogeneity of HPV status in individual cells, further clarification of HPV infection at the single-cell level may refine our understanding of HPV-related carcinogenesis.

Genetic diversity of HPV16 and HPV18 in Brazilian patients with invasive cervical cancer

Cervical cancer is the fourth most common cancer among women, and ∼70-80% of these cancers are associated with two human papillomavirus types: HPV16 and HPV18. Several studies have reported that intra-type diversity is associated with the progression of infection to invasive cancer. Herein, we report the genetic diversity of HPV16 and HPV18 in a cohort of 594 Brazilian women with invasive cervical cancer and describe the prevalence of lineages and intra-type diversity prior to the implementation of the public immunization program in Brazil. HPV detection and genotyping were performed using PCR, PGMY/GP primers, and DNA extracted from fresh tumors. The HPV16 (378 women) and HPV18 (80 women) lineages were identified by PCR and sequencing of the LCR and E6 fragments, followed by SNV comparison and phylogenetic analysis. In our cohort, was found a higher frequency of the lineage A (in 217 women), followed by lineage D (in 97 women) and lineages B and C (in 10 women each) for HPV16; and a higher frequency of lineage A (in 56 women) followed by lineage B (in 15 women) in HPV18. The genetic diversity of HPV16 indicated a recent expansion of specific variants or a selective advantage that is associated with invasive cancer; this pattern was not observed for HPV18.

HPV vaccination for prevention of skin cancer

Cutaneous papillomaviruses are associated with specific skin diseases, such as extensive wart formation and the development of non-melanoma skin cancer (NMSC), especially in immunosuppressed patients. Hence, clinical approaches are required that prevent such lesions. Licensed human papillomavirus (HPV) vaccines confer type-restricted protection against HPV types 6, 11, 16 and 18, responsible of 90% of genital warts and 70% of cervical cancers, respectively. However, they do not protect against less prevalent high-risk types or cutaneous HPVs. Over the past few years, several studies explored the potential of developing vaccines targeting cutaneous papillomaviruses. These vaccines showed to be immunogenic and prevent skin tumor formation in certain animal models. Furthermore, under conditions mimicking the ones found in the intended target population (i.e., immunosuppression and in the presence of an already established infection before vaccination), recent preclinical data shows that immunization can still be effective. Strategies are currently focused on finding vaccine formulations that can confer protection against a broad range of papillomavirus-associated diseases. The state-of-the-art of these approaches and the future directions in the field will be presented.

Human papillomavirus vaccination in HIV-infected women: need for increased coverage

Human immunodeficiency virus (HIV)-infected women carry a significant burden on human papillomavirus (HPV) infection and associated diseases. As HIV-infected individuals are living longer, the prevalence of HPV infection is rising and HPV-associated cytological abnormalities remain high despite successful treatments of HIV infection. Several HPV vaccines are currently available and recommended for adolescents and adults up to age 26. The vaccines are safe, immunogenic and effective in preventing diseases due to HPV types included in the vaccines, particularly among persons without prior HPV exposure. This review summarizes available data on the use of the HPV vaccines among HIV-infected women. The immunogenicity and safety of the vaccines are highlighted and in particular, barriers to vaccination among HIV-infected women are discussed.

New Type of Papillomavirus and Novel Circular Single Stranded DNA Virus Discovered in Urban Rattus norvegicus Using Circular DNA Enrichment and Metagenomics

Rattus norvegicus (R. norvegicus) are ubiquitous and their presence has several effects on the human populations in our urban areas on a global scale. Both historically and presently, this close interaction has facilitated the dissemination of many pathogens to humans, making screening for potentially zoonotic and emerging viruses in rats highly relevant. We have investigated faecal samples from R. norvegicus collected from urban areas using a protocol based on metagenomic enrichment of circular DNA genomes and subsequent sequencing. We found a new type of papillomavirus, with a L1 region 82% identical to that of the known R. norvegicus Papillomavirus 2. Additionally, we found 20 different circular replication associated protein (Rep)-encoding single stranded DNA (CRESS-DNA) virus-like genomes, one of which has homology to the replication-associated gene of Beak and feather disease virus. Papillomaviruses are a group of viruses known for their carcinogenic potential, and although they are known to infect several different vertebrates, they are mainly studied and characterised in humans. CRESS-DNA viruses are found in many different environments and tissue types. Both papillomaviruses and CRESS-DNA viruses are known to have pathogenic potential and screening for novel and known viruses in R. norvegicus could help identify viruses with pathogenic potential.

Rusa alfredi papillomavirus 1 - a novel deltapapillomavirus inducing endemic papillomatosis in the endangered Visayan spotted deer

We describe a novel papillomavirus - Rusa alfredi papillomavirus 1 (RalPV1) - which causes endemic fibropapillomatosis in the European conservation breeding population of the highly endangered Visayan spotted deer (Rusa alfredi). Degenerated papillomavirus-specific primers were used to amplify and sequence parts of the viral DNA. Subsequently, the complete genomic DNA was cloned and the sequence was determined. The RalPV1 genome has a length of 8029 bp, encodes the early proteins E6, E7, E1, E2 and E5, the two late proteins L1 and L2 and contains an upstream regulatory region. Highest sequence identities were observed with two deltapapillomaviruses, the Capreolus capreolus PV1 and Cervus elaphus PV1. Pairwise comparisons and phylogenetic analysis based on the ORF L1 suggested that RalPV1 is a putative new type of the papillomavirus species Deltapapillomavirus 5.

Comparison of three human papillomavirus DNA detection methods: Next generation sequencing, multiplex-PCR and nested-PCR followed by Sanger based sequencing

To compare the diagnostic performance for HPV infection using three laboratorial techniques. Ninty-five cervicovaginal samples were randomly selected; each was tested for HPV DNA and genotypes using 3 methods in parallel: Multiplex-PCR, the Nested PCR followed by Sanger sequencing, and the Next_Gen Sequencing (NGS) with two assays (NGS-A1, NGS-A2). The study was approved by the Brazilian National IRB (CONEP protocol 16,800). The prevalence of HPV by the NGS assays was higher than that using the Multiplex-PCR (64.2% vs. 45.2%, respectively; P = 0.001) and the Nested-PCR (64.2% vs. 49.5%, respectively; P = 0.003). NGS also showed better performance in detecting high-risk HPV (HR-HPV) and HPV16. There was a weak interobservers agreement between the results of Multiplex-PCR and Nested-PCR in relation to NGS for the diagnosis of HPV infection, and a moderate correlation for HR-HPV detection. Both NGS assays showed a strong correlation for detection of HPVs (k = 0.86), HR-HPVs (k = 0.91), HPV16 (k = 0.92) and HPV18 (k = 0.91). NGS is more sensitive than the traditional Sanger sequencing and the Multiplex PCR to genotype HPVs, with promising ability to detect multiple infections, and may have the potential to establish an alternative method for the diagnosis and genotyping of HPV.

Commercially available molecular tests for human papillomaviruses (HPV): 2015 update

Commercial molecular tests for human papillomaviruses (HPV) are invaluable diagnostic tools in cervical carcinoma screening and management of women with cervical precancerous lesions as well as important research tools for epidemiological studies, vaccine development, and implementation and monitoring of vaccination programs. In this third inventory of commercial HPV tests, we identified 193 distinct commercial HPV tests and at least 127 test variants available on the market in 2015, which represents a 54% and 79% increase in the number of distinct HPV tests and variants, respectively, in comparison to our last inventory performed in 2012. Identified HPV tests were provisionally divided into eight main groups and several subgroups. Among the 193 commercial HPV tests, all but two target alpha-HPV types only. Although the number of commercial HPV tests with at least one published study in peer-reviewed literature has increased significantly in the last three years, several published performance evaluations are still not in line with agreed-upon standards in the HPV community. Manufacturers should invest greater effort into evaluating their products and publishing validation/evaluation results in peer-reviewed journals. To achieve this, more clinically oriented external quality-control panels and initiatives are required. For evaluating the analytical performance of the entire range of HPV tests currently on the market, more diverse and reliable external quality-control programs based on international standards for all important HPV types are indispensable. The performance of a wider range of HPV tests must be promptly evaluated on a variety of alternative clinical specimens. In addition, more complete HPV assays containing validated sample-extraction protocols and appropriate internal controls are urgently needed. Provision of a broader range of automated systems allowing large-scale HPV testing as well as the development of reliable, rapid, and affordable molecular point-of-care tests are priorities for the further improvement of HPV tests.

Initial amplification of the HPV18 genome proceeds via two distinct replication mechanisms

Determining the mechanism of HPV18 replication is paramount for identifying possible drug targets against HPV infection. We used two-dimensional and three-dimensional gel electrophoresis techniques to identify replication intermediates arising during the initial amplification of HPV18 episomal genomes. We determined that the first rounds of HPV18 replication proceed via bidirectional theta structures; however, a notable accumulation of almost fully replicated HPV18 genomes indicates difficulties with the completion of theta replication. We also observed intermediates that were created by a second replication mechanism during the initial amplification of HPV18 genomes. The second replication mechanism does not utilize specific initiation or termination sequences and proceeds via a unidirectional replication fork. We suggest a significant role for the second replication mechanism during the initial replication of the HPV18 genome and propose that the second replication mechanism is recombination-dependent replication.

Cross-protection of the Bivalent Human Papillomavirus (HPV) Vaccine Against Variants of Genetically Related High-Risk HPV Infections

BACKGROUND

Results from the Costa Rica Vaccine Trial (CVT) demonstrated partial cross-protection by the bivalent human papillomavirus (HPV) vaccine, which targets HPV-16 and HPV-18, against HPV-31, -33, and -45 infection and an increased incidence of HPV-51 infection.

METHODS

A study nested within the CVT intention-to-treat cohort was designed to assess high-risk HPV variant lineage-specific vaccine efficacy (VE). The 2 main end points were (1) long-term incident infections persisting for ≥2 years and/or progression to high-grade squamous intraepithelial lesions (ie, cervical intraepithelial neoplasia grade 2/3 [CIN 2/3]) and (2) incident transient infections lasting for <2 years. For efficiency, incident infections due to HPV-16, -18, -31, -33, -35, -45, and -51 resulting in persistent infection and/or CIN 2/3 were matched (ratio, 1:2) to the more-frequent transient viral infections, by HPV type. Variant lineages were determined by sequencing the upstream regulatory region and/or E6 region.

RESULTS

VEs against persistent or transient infections with HPV-16, -18, -33, -35, -45, and -51 did not differ significantly by variant lineage. As the possible exception, VEs against persistent infection and/or CIN 2/3 due to HPV-31 A/B and HPV-31C variants were -7.1% (95% confidence interval [CI], -33.9% to 0%) and 86.4% (95% CI, 65.1%-97.1%), respectively (P = .02 for test of equal VE). No difference in VE was observed by variant among transient HPV-31 infections (P = .68).

CONCLUSIONS

Overall, sequence variation at the variant level does not appear to explain partial cross-protection by the bivalent HPV vaccine.

Immunologic Control of Mus musculus Papillomavirus Type 1

Persistent papillomas developed in ~10% of out-bred immune-competent SKH-1 mice following MusPV1 challenge of their tail, and in a similar fraction the papillomas were transient, suggesting potential as a model. However, papillomas only occurred in BALB/c or C57BL/6 mice depleted of T cells with anti-CD3 antibody, and they completely regressed within 8 weeks after depletion was stopped. Neither CD4+ nor CD8+ T cell depletion alone in BALB/c or C57BL/6 mice was sufficient to permit visible papilloma formation. However, low levels of MusPV1 were sporadically detected by either genomic DNA-specific PCR analysis of local skin swabs or in situ hybridization of the challenge site with an E6/E7 probe. After switching to CD3+ T cell depletion, papillomas appeared upon 14/15 of mice that had been CD4+ T cell depleted throughout the challenge phase, 1/15 of CD8+ T cell depleted mice, and none in mice without any prior T cell depletion. Both control animals and those depleted with CD8-specific antibody generated MusPV1 L1 capsid-specific antibodies, but not those depleted with CD4-specific antibody prior to T cell depletion with CD3 antibody. Thus, normal BALB/c or C57BL/6 mice eliminate the challenge dose, whereas infection is suppressed but not completely cleared if their CD4 or CD8 T cells are depleted, and recrudescence of MusPV1 is much greater in the former following treatment with CD3 antibody, possibly reflecting their failure to generate capsid antibody. Systemic vaccination of C57BL/6 mice with DNA vectors expressing MusPV1 E6 or E7 fused to calreticulin elicits potent CD8 T cell responses and these immunodominant CD8 T cell epitopes were mapped. Adoptive transfer of a MusPV1 E6-specific CD8+ T cell line controlled established MusPV1 infection and papilloma in RAG1-knockout mice. These findings suggest the potential of immunotherapy for HPV-related disease and the importance of host immunogenetics in the outcome of infection.

While most patients clear human papillomavirus (HPV) infection, some develop persistent papillomas, especially if immunocompromised. Likewise, we find a fraction of outbred SKH-1 mice challenged with Mus musculus papillomavirus type 1 (MusPV1/MmuPV1) develop persistent papillomas, whereas most SKH-1 mice, as seen for the inbred C57BL/6 and BALB/c strains, clear the infection. Viral clearance requires both CD4+ and CD8+ T cells, and depletion of either subset permits persistent but subclinical infection. In C57BL/6 mice, CD8+ T cell epitopes were mapped to MusPV1 E6 and E7; however the CD8+ T cell response to E6 dominated and correlated with spontaneous regression. A MusPV1 E6-specific CD8+ T cell line was developed by vaccination and culture in vitro, and its systemic administration once was sufficient to effect papilloma clearance in an immunodeficient mouse. Our observations in inbred and outbred mice challenged with MusPV1 suggest promise for immunotherapy to treat HPV-associated disease.

Human papillomavirus genotyping by Linear Array and Next-Generation Sequencing in cervical samples from Western Mexico

BACKGROUND

The Linear Array® (LA) genotyping test is one of the most used methodologies for Human papillomavirus (HPV) genotyping, in that it is able to detect 37 HPV genotypes and co-infections in the same sample. However, the assay is limited to a restricted number of HPV, and sequence variations in the detection region of the HPV probes could give false negatives results. Recently, 454 Next-Generation sequencing (NGS) technology has been efficiently used also for HPV genotyping; this methodology is based on massive sequencing of HPV fragments and is expected to be highly specific and sensitive. In this work, we studied HPV prevalence in cervixes of women in Western Mexico by LA and confirmed the genotypes found by NGS.

METHODS

Two hundred thirty three cervical samples from women Without cervical lesions (WCL, n = 48), with Cervical intraepithelial neoplasia grade 1 (CIN I, n = 98), or with Cervical cancer (CC, n = 87) were recruited, DNA was extracted, and HPV positivity was determined by PCR amplification using PGMY09/11 primers. All HPV- positive samples were genotyped individually by LA. Additionally, pools of amplicons from the PGMY-PCR products were sequenced using 454 NGS technology. Results obtained by NGS were compared with those of LA for each group of samples.

RESULTS

We identified 35 HPV genotypes, among which 30 were identified by both technologies; in addition, the HPV genotypes 32, 44, 74, 102 and 114 were detected by NGS. These latter genotypes, to our knowledge, have not been previously reported in Mexican population. Furthermore, we found that LA did not detect, in some diagnosis groups, certain HPV genotypes included in the test, such as 6, 11, 16, 26, 35, 51, 58, 68, 73, and 89, which indicates possible variations at the species level.

CONCLUSIONS

There are HPV genotypes in Mexican population that cannot be detected by LA, which is, at present, the most complete commercial genotyping test. More studies are necessary to determine the impact of HPV-44, 74, 102 and 114 on the risk of developing CC. A greater number of samples must be analyzed by NGS for the most accurate determination of Mexican HPV variants.

Human papillomavirus molecular biology and disease association

Human papillomaviruses (HPVs) have evolved over millions of years to propagate themselves in a range of different animal species including humans. Viruses that have co‐evolved slowly in this way typically cause chronic inapparent infections, with virion production in the absence of apparent disease. This is the case for many Beta and Gamma HPV types. The Alpha papillomavirus types have however evolved immunoevasion strategies that allow them to cause persistent visible papillomas. These viruses activate the cell cycle as the infected epithelial cell differentiates in order to create a replication competent environment that allows viral genome amplification and packaging into infectious particles. This is mediated by the viral E6, E7, and E5 proteins. High‐risk E6 and E7 proteins differ from their low‐risk counterparts however in being able to drive cell cycle entry in the upper epithelial layers and also to stimulate cell proliferation in the basal and parabasal layers. Deregulated expression of these cell cycle regulators underlies neoplasia and the eventual progression to cancer in individuals who cannot resolve high‐risk HPV infection. Most work to date has focused on the study of high‐risk HPV types such as HPV 16 and 18, which has led to an understanding of the molecular pathways subverted by these viruses. Such approaches will lead to the development of better strategies for disease treatment, including targeted antivirals and immunotherapeutics. Priorities are now focused toward understanding HPV neoplasias at sites other than the cervix (e.g. tonsils, other transformation zones) and toward understanding the mechanisms by which low‐risk HPV types can sometimes give rise to papillomatosis and under certain situations even cancers. Copyright © 2015 John Wiley & Sons, Ltd.

Pharmacophore Modeling and Molecular Docking Studies of potential inhibitors to E6 PBM-PDZ from Human Papilloma Virus (HPV)

High-risk human papillomaviruses (HPVs) are known to cause cervical cancer. Vaccines are now available to prevent HPV infection. However, a clinically approved drug is yet not available to treat HPV. The PDZ(PSD−95/Dlg/ZO−1)−binding motif (PBM) in the E6 protein of HPVs targets the PDZ domain (known to be associated with oncogenesis) for degradation. Therefore, it is of interest to study PBM–PDZ interaction towards its possible inhibition with a potential inhibitor. Thus, four pharmocophore models of PBM−PDZ complex were developed. In order to obtain potent small molecules for its inhibition, a commercial compound database was screened using both these pharmacophore models and molecule docking method. These efforts identified four potential compounds (1−4) towards its inhibition with the docking scores range -18.2 to -15.0.

Regulation of the Wnt/β-Catenin Signaling Pathway by Human Papillomavirus E6 and E7 Oncoproteins

Cell signaling pathways are the mechanisms by which cells transduce external stimuli, which control the transcription of genes, to regulate diverse biological effects. In cancer, distinct signaling pathways, such as the Wnt/β-catenin pathway, have been implicated in the deregulation of critical molecular processes that affect cell proliferation and differentiation. For example, changes in β-catenin localization have been identified in Human Papillomavirus (HPV)-related cancers as the lesion progresses. Specifically, β-catenin relocates from the membrane/cytoplasm to the nucleus, suggesting that this transcription regulator participates in cervical carcinogenesis. The E6 and E7 oncoproteins are responsible for the transforming activity of HPV, and some studies have implicated these viral oncoproteins in the regulation of the Wnt/β-catenin pathway. Nevertheless, new interactions of HPV oncoproteins with cellular proteins are emerging, and the study of the biological effects of such interactions will help to understand HPV-related carcinogenesis. This review addresses the accumulated evidence of the involvement of the HPV E6 and E7 oncoproteins in the activation of the Wnt/β-catenin pathway.

Human papillomavirus status, anal cytology and histopathological outcome in HIV-positive patients

BACKGROUND

Human papillomavirus (HPV) are responsible for a broad spectrum of mucocutaneous infections and may cause squamous cell carcinoma following long-standing infection . Oncogenic HPV, most commonly HPV 16, are detectable in over 90% of cervical intraepithelial neoplasia and anal intraepithelial neoplasia (AIN). Human immunodeficiency virus (HIV) infection is strongly associated with a higher prevalence of chronic HPV infection, a higher incidence of AIN and an increased risk for anal cancer (AC). In September 2013, guidelines concerning prevention, screening and treatment of AIN for patients affected by HIV were issued by the German AIDS society.

OBJECTIVE

In order to validate the suggested screening procedure, we analysed data from 123 male and female patients with HIV infection that regularly present in our outpatient clinic.

METHODS

Anal cytology, HPV typing and high-resolution anoscopy (HRA) were performed.

RESULTS

Our results show that screening by anal cytology only identifies a minority of patients with high grade AIN (AIN 3) histology. Patients with normal cytology (NILM, cytology graded negative for intraepithelial lesion or malignancy; n = 5, 29.4%), atypical squamous cells of undetermined significance (ASCUS; n = 5, 71.4%) and low grade squamous intraepithelial lesion (LSIL; n = 8, 44.5%) showed highly dysplastic lesions (AIN 2 and 3) in the histological workup more frequently than expected. Additionally, high-grade squamous intraepithelial lesion (HSIL) was strongly associated with detection of high-risk oncogenic HPV.

CONCLUSION

Anal cytology as the solitary screening tool for anal cancer fails to detect anal dysplasia in a considerable number of patients. Additionally, HPV typing and possibly further biomarkers might be applied to identify those patients with a higher risk of developing anal carcinoma, in order to monitor them more closely or directly transfer them to HRA.