Accuracy of HPV E6/E7 oncoprotein tests to detect high-grade cervical lesions: a systematic literature review and meta-analysis

BACKGROUND

Cervical carcinogenesis is mediated by the HPV-E6 and E7 oncoproteins, considered as biomarkers usable in managing screen-positive women.

METHODS

We conducted a systematic review and meta-analysis assessing the accuracy of HPV-E6/E7-oncoprotein tests to detect underlying cervical-precancer and cancer. We included studies reporting data on oncoprotein test accuracy detecting cervical intraepithelial neoplasia grade 3 or worse. Random effects logistic regression models were applied for pooling absolute and relative accuracy.

RESULTS

Twenty-two studies were included. Sensitivity and specificity estimates ranged from 54.2% (95%CI: 45.2-63.0) to 69.5% (95%CI:60.8-76.9) and from 82.8% (95%CI: 50.4-95.8) to 99.1 (95%CI: 98.8-99.3), respectively in the population irrespective of HPV status. Higher sensitivity estimates ranging from 60.8% (95%CI: 49.6-70.9) to 75.5% (95%CI: 71.7-78.9) but lower specificity estimates ranging from 83.7% (95%CI: 76.1-89.3) to 92.1% (95%CI: 88.5-94.6) were observed in studies enrolling high-risk-HPV-positive women. Studies recruiting only HIV-positive women showed a pooled sensitivity of 46.9% (95%CI: 30.6-63.9) with a specificity of 98.0% (95%CI: 96.8-98.7).

CONCLUSIONS

The high specificity of oncoprotein tests supports its use for triaging HPV-positive women. However, oncoprotein-negative women would not be recommended to undertake routine screening, requiring further follow-up. Large-scale and longitudinal studies are needed to further investigate the role of E6/E7-oncoprotein detection in predicting the risk of developing cervical pre-cancer and cancer.

Melt Processing Virus-Like Particle-Based Vaccine Candidates into Biodegradable Polymer Implants

Melt processing is an emerging production method to efficiently encapsulate proteins into polymeric devices for sustained release. In the context of vaccines, melt processing is well-suited to develop vaccine delivery devices that are stable outside the cold chain and can generate protective immunity from a single dose. We have demonstrated the compatibility of bacteriophage Qβ virus-like particles (VLPs) with hot-melt extrusion (HME) and have leveraged this technology to develop a single-dose vaccine candidate for vaccination against human papillomavirus (HPV). Here, we detail the methods for chemically conjugating an HPV peptide epitope from the L2 minor capsid protein to Qβ VLPs to generate HPV-Qβ particles. We outline techniques used to characterize HPV-Qβ particles, and we elaborate on the process to encapsulate HPV-Qβ into biodegradable poly(lactic-co-glycolic acid) (PLGA) implants and discuss methods for the materials characterization of the HPV-Qβ/polymer melts. The methods described could be adapted to other disease targets, i.e., by conjugation of a different peptide epitope, or transferred to other VLP systems suited for conjugation, immune response, or stability during processing. Such VLPs are ideally suited for use in HME, a mature, scalable, continuous, and solvent-free process which can be adapted to mold devices, therefore allowing the processing of the melts into various geometries, such as subcutaneous implants, or self-administrable microneedle patches.

Immunotherapy that leverages HPV-specific immune responses for precancer lesions of cervical cancer

Cervical cancer and its precursor lesion, cervical intraepithelial neoplasia (CIN), are caused by high-risk human papillomavirus (HPV) viral infection and are highly susceptible to host immunity targeting of HPV viral proteins, which include both foreign antigens and cancer antigens expressed by tumors. Immunotherapy that induces Th1 immunoreactivity against viral proteins is expected to take advantage of this immunological regression mechanism. However, although cancer immunotherapies for cervical cancer and CIN have been developed over the past several decades, none have been commercialized. Most of these immunotherapies target the viral cancer proteins E6 and E7, which are generally the same. The reasons for the underdevelopment of HPV-targeted immunotherapy differ depending on whether the target is invasive cancer or CIN. We here summarize the developmental history of cancer immunotherapy for CIN and discuss strategies for solving the problems that led to this underdevelopment. We note that CIN is a mucosal lesion and propose that inducing mucosal immunity may be the key.

Solvent-free synthesis and in-silico molecular docking study of (E)-3-(β-C-glycosylmethylidene)-N-aryl/alkyl succinimides

Globally, human papillomavirus (HPV) infection is the leading cause of mortality associated with cervical cancer, oral cancer (oropharyngeal), and head and neck squamous cell carcinoma (HNSCC). It is essential to explore anti-cancer drugs against life-threatening HPV infections. Aiming to search for potentially better anticancer agents, a small library of β-C-glycosylated methylidene succinimides have been synthesized under bulk and mechanical grinding conditions using the Wittig olefination reaction. Thus, the reaction of different 2,3,4,6-tetra-O-benzyl-C-glycosyl aldehydes with N-aryl/alkyl maleimides in the presence of PPh3 at 25 °C under bulk and mechanical grinding conditions results in the formation of stereochemically defined (E)-3-(2,3,4,6-tetra-O-benzyl-C-glycosylmethylidene)-N-alkyl/phenyl succinimides, which upon debenzylation with 1 M BCl3 in DCM at -78 °C lead to the synthesis of (E)-3-(C-glycosylmethylidene)-N-alkyl/phenyl succinimides in good to excellent yields. The developed methodology is efficient and environmentally benign because there is no use of organic solvents, and the products are obtained in a stereochemically defined form and in high yields. The aqueous solubility of all synthesized β-C-glycosylated methylidene succinimides makes them potential candidates for the evaluation of their different biological activities. In the present work, the synthesized glycosylated alkylidine succinimides were subjected to an in-silico molecular docking study against the E6 oncoprotein of high-risk type HPV16, which is responsible for the inactivation of the tumor suppressor p53 protein. Analysis of the molecular docking data revealed that the synthesized compounds are effective inhibitors of HPV infection, which is the cause of oral, head and neck, and cervical cancer. In comparison with the positive control 5-FU, an anti-cancer drug used in chemotherapy, more than fifteen compounds were found to be better E6 protein inhibitors.

The effects of HPV oncoproteins on host communication networks: Therapeutic connotations

Human papillomavirus (HPV) infections are a leading cause of viral-induced malignancies worldwide, with a prominent association with cervical and head and neck cancers. The pivotal role of HPV oncoproteins, E5, E6, and E7, in manipulating cellular events, which contribute to viral pathogenesis in various ways, has been extensively documented. This article reviews the influence of HPV oncoproteins on cellular signaling pathways within the host cell, shedding light on the underlying molecular mechanisms. A comprehensive understanding of these molecular alterations is essential for the development of targeted therapies and strategies to combat HPV-induced premalignancies and prevent their progress to cancer. Furthermore, this review underscores the intricate interplay between HPV oncoproteins and some of the most important cellular signaling pathways: Notch, Wnt/β-catenin, MAPK, JAK/STAT, and PI3K AKT/mTOR. The treatment efficacies of the currently available inhibitors on these pathways in an HPV-positive context are also discussed. This review also highlights the importance of continued research to advance our knowledge and enhance therapeutic interventions for HPV-associated diseases.

Molecular characterization and phylogenetic analysis of Marek's disease virus in chickens from Ogun State, Nigeria

Marek's disease (MD) is caused by oncogenic MD virus serotype 1 (MDV1) and is characterized by lymphoproliferative lesions resulting in high morbidity and mortality in chickens. Despite being ubiquitous on poultry farms, there is a dearth of information on its molecular characteristics in Nigeria. This study aimed at characterizing three virulence genes (Meq, pp38, and vIL-8) of MDV1 from chickens in Ogun state, Nigeria. Blood, feather quill, and tumour samples of chickens from different commercial poultry farms in Ogun State were pooled, spotted on 107 FTA cards, and screened for MDV1 by polymerase chain reaction (PCR). Phylogenetic analysis was carried out to compare Nigerian MDV1 Meq, pp38, and vIL-8 genes sequences with the published references. Thirteen samples were MDV1-positive and the Meq, as well as pp38, and vIL-8 genes from the different samples were 100% identical. The Meq genes contained 339 amino acids (aa) with three PPPP motifs in the transactivation domain and two interruptions of the PPPP motifs due to proline-to-arginine substitutions at positions 176 and 217 resulting in a 20.88% proline composition. Phylogenetic analysis revealed that the Meq gene clustered with strains from Egypt and very virulent ATE2539 strain from Hungary. Mutations were observed in the pp38 protein (at positions 107 and 109) and vIL-8 protein (at positions 4 and 31). Based on the molecular analysis of the three genes, the results indicate the presence of MDV1 with virulence signatures; therefore, further studies on in vivo pathotyping of Nigerian MDV1 from all states should be performed.RESEARCH HIGHLIGHTS Meq, pp38 and vIL-8 genes were 100% identical between Nigerian MDV strains.Proline content in Nigerian meq gene was 20.88% with two PPPP motifs interruptions.Meq, pp38 and vIL-8 genes of Nigerian MDV were similar to Egyptian and Indian strains.

Role of extracellular vesicle in human papillomavirus-associated cervical cancer

BACKGROUND

Cervical cancer is a gynecological malignant tumor and a serious threat to women's health. Although human papillomavirus (HPV) infection and the occurrence of cervical cancer are known to be closely related, the underlying carcinogenic mechanism of HPV is not fully understood. Extracellular vesicles (EVs) are found in a variety of body fluids and play an important role in both intercellular communication and cancer progression. Furthermore, the presence of EVs makes liquid biopsy of cervical cancer possible. The study of EVs in cervical cancer can provide clinical ideas for the diagnosis and treatment of the disease.

OBJECTIVES

The purpose of this article is to summarizes the role of EV contents in HPV-associated cervical cancer and discusses the possible clinical application of EVs in cervical cancer treatment.

METHODS

The search terms included the following: HPV with cervical cancer and extracellular vesicles. The initial literature search ended on March 1, 2023.

CONCLUSIONS

In HPV-positive cervical cancer, EV contents are changed due to the presence of HPV. HPV-positive cervical cancer affects the cell microenvironment and other surrounding cells through the secretion of EVs.

Phase 1 study to determine the safety and dosing of autologous PBMCs modified to present HPV16 antigens (SQZ-PBMC-HPV) in HLA-A*02+ patients with HPV16+ solid tumors

We conducted a dose escalation Phase 1 study of autologous PBMCs loaded by microfluidic squeezing (Cell Squeeze® technology) with HPV16 E6 and E7 antigens (SQZ-PBMC-HPV), in HLA-A*02+ patients with advanced/metastatic HPV16+ cancers. Preclinical studies in murine models had shown such cells resulted in stimulation and proliferation of antigen specific CD8+ cells, and demonstrated antitumor activity. Administration of SQZ-PBMC-HPV was every 3 weeks. Enrollment followed a modified 3+3 design with primary objectives to define safety, tolerability, and the recommended Phase 2 dose. Secondary and exploratory objectives were antitumor activity, manufacturing feasibility, and pharmacodynamic evaluation of immune responses. Eighteen patients were enrolled at doses ranging from 0.5 × 106 to 5.0 × 106 live cells/kg. Manufacture proved feasible and required < 24 h within the overall vein-to-vein time of 1 - 2 weeks; at the highest dose, a median of 4 doses were administered. No DLTs were observed. Most related TEAEs were Grade 1 - 2, and one Grade 2 cytokine release syndrome SAE was reported. Tumor biopsies in three patients showed 2 to 8-fold increases in CD8+ tissue infiltrating lymphocytes, including a case that exhibited increased MHC-I+ and PD-L1+ cell densities and reduced numbers of HPV+ cells. Clinical benefit was documented for the latter case. SQZ-PBMC-HPV was well tolerated; 5.0 × 106 live cells/kg with double priming was chosen as the recommended Phase 2 dose. Multiple participants exhibited pharmacodynamic changes consistent with immune responses supporting the proposed mechanism of action for SQZ-PBMC-HPV, including patients previously refractory to checkpoint inhibitors.

Usefulness of high-risk HPV early oncoprotein (E6 and E7) serological markers in the detection of cervical cancer: A systematic review and meta-analysis

We reviewed the literature on the importance of selected anti-high-risk human papillomavirus (HR-HPV) antibodies (namely, 16/18 and early oncoproteins E6 and E7) as potential serological markers for early detection of individuals at high risk of cervical cancer. We searched for studies in PubMed and Embase databases published from 2010 to 2020 on antibodies against HR-HPV E6 and E7 early proteins and cervical cancer. Pooled sensitivity and specificity for HPV16 and HPV18 antibodies were calculated using a bivariate hierarchical random-effects model. A total of 69 articles were identified; we included three studies with 1550 participants. For the three HPV16/18 E6 and E7 antibody tests, enzyme-linked immunosorbent assay-based assays had a sensitivity of 18% for detecting CIN2+ (95% confidence interval [CI]: 15-21) and a specificity of 96% (95% CI: 92-98), for slot-blot, sensitivity was 28.9% (95% CI: 23.3-35.1) and specificity was 72% (95% CI: 66.6-77.0) for detecting CIN2+, and for multiplex HPV serology assay based on a glutathione S-transferase, sensitivity was 16% (95% CI: 8.45-28.6) and specificity was 98% (95% CI: 97-99) for detecting invasive cervical cancer. HR-HPV16/18 E6 and E7 serological markers showed high specificity, but sensitivity was suboptimal for the detection of cervical cancer in either population screening settings or as point-of-care screening tests.

Absolute Risk of Oropharyngeal Cancer After an HPV16-E6 Serology Test and Potential Implications for Screening: Results From the Human Papillomavirus Cancer Cohort Consortium

PURPOSE

Seropositivity for the HPV16-E6 oncoprotein is a promising marker for early detection of oropharyngeal cancer (OPC), but the absolute risk of OPC after a positive or negative test is unknown.

METHODS

We constructed an OPC risk prediction model that integrates (1) relative odds of OPC for HPV16-E6 serostatus and cigarette smoking from the human papillomavirus (HPV) Cancer Cohort Consortium (HPVC3), (2) US population risk factor data from the National Health Interview Survey, and (3) US sex-specific population rates of OPC and mortality.

RESULTS

The nine HPVC3 cohorts included 365 participants with OPC with up to 10 years between blood draw and diagnosis and 5,794 controls. The estimated 10-year OPC risk for HPV16-E6 seropositive males at age 50 years was 17.4% (95% CI, 12.4 to 28.6) and at age 60 years was 27.1% (95% CI, 19.2 to 45.4). Corresponding 5-year risk estimates were 7.3% and 14.4%, respectively. For HPV16-E6 seropositive females, 10-year risk estimates were 3.6% (95% CI, 2.5 to 5.9) at age 50 years and 5.5% (95% CI, 3.8 to 9.2) at age 60 years and 5-year risk estimates were 1.5% and 2.7%, respectively. Over 30 years, after a seropositive result at age 50 years, an estimated 49.9% of males and 13.3% of females would develop OPC. By contrast, 10-year risks among HPV16-E6 seronegative people were very low, ranging from 0.01% to 0.25% depending on age, sex, and smoking status.

CONCLUSION

We estimate that a substantial proportion of HPV16-E6 seropositive individuals will develop OPC, with 10-year risks of 17%-27% for males and 4%-6% for females age 50-60 years in the United States. This high level of risk may warrant periodic, minimally invasive surveillance after a positive HPV16-E6 serology test, particularly for males in high-incidence regions. However, an appropriate clinical protocol for surveillance remains to be established.

Next generation L2-based HPV vaccines cross-protect against cutaneous papillomavirus infection and tumor development

Licensed L1-VLP-based immunizations against high-risk mucosal human papillomavirus (HPV) types have been a great success in reducing anogenital cancers, although they are limited in their cross-protection against HPV types not covered by the vaccine. Further, their utility in protection against cutaneous HPV types, of which some contribute to non-melanoma skin cancer (NMSC) development, is rather low. Next generation vaccines achieve broadly cross-protective immunity against highly conserved sequences of L2. In this exploratory study, we tested two novel HPV vaccine candidates, HPV16 RG1-VLP and CUT-PANHPVAX, in the preclinical natural infection model Mastomys coucha. After immunization with either vaccines, a mock control or MnPV L1-VLPs, the animals were experimentally infected and monitored. Besides vaccine-specific seroconversion against HPV L2 peptides, the animals also developed cross-reactive antibodies against the cutaneous Mastomys natalensis papillomavirus (MnPV) L2, which were cross-neutralizing MnPV pseudovirions in vitro. Further, both L2-based vaccines also conferred in vivo protection as the viral loads in plucked hair after experimental infection were lower compared to mock-vaccinated control animals. Importantly, the formation of neutralizing antibodies, whether directed against L1-VLPs or L2, was able to prevent skin tumor formation and even microscopical signs of MnPV infection in the skin. For the first time, our study shows the proof-of-principle of next generation L2-based vaccines even across different PV genera in an infection animal model with its genuine PV. It provides fundamental insights into the humoral immunity elicited by L2-based vaccines against PV-induced skin tumors, with important implications to the design of next generation HPV vaccines.

Antiproliferative and Pro-Apoptotic Effects of a Phenolic-Rich Extract from Lycium barbarum Fruits on Human Papillomavirus (HPV) 16-Positive Head Cancer Cell Lines

The in vitro antiproliferative activity of a phenolic-rich extract from Lycium barbarum fruits against head and neck HPV16 squamous cell carcinoma (OSCC) has been demonstrated, indicating for the first time that L. barbarum extract inhibits human papillomavirus (HPV) type 16 cell lines. Ethanol extract of L. barbarum was used for cell viability evaluation on SCC090, CAL27, and HGnF cell lines. After 24 and 48 h, the cell cycle effect of L. barbarum extract (at 1.0, 10, and 100 µg/mL) was measured via flow cytometry. In addition, the mRNA expression on E6/E7 and p53 via RT-PCR and the expression of p16, p53, Ki-67, and Bcl-2 via immunohistochemistry were also determined. Untreated cells, 20 µM cisplatin, and a Camellia sinensis-derived extract were used as negative and positive controls, respectively. We demonstrated that the studied L. barbarum extract resulted in G0/G1 arrest and S phase accumulation in SCC090 at 1.0 and 10 μg/mL. A reduction in mRNA levels of E6/E7 oncogenes (p < 0.05) with p53 overexpression was also observed through PCR, while immunohistochemical analyses indicated p16 overexpression (p > 0.05) and a decrease in p53 overexpression. The observed effects were associated with anticancer and immunomodulatory phenolics, such as flavonols/flavan-3-ols and tyramine-conjugated hydroxycinnamic acid amides, identified in the studied extract. These findings revealed that the phenolic-rich extract of L. barbarum fruits has promising properties to be considered further for developing new therapies against oral and oropharyngeal HPV lesions.

New insights into the interactions of HPV-16 E6*I and E6*II with p53 isoforms and induction of apoptosis in cancer-derived cell lines

An important characteristic of cancers associated with high-risk human papillomaviruses (HR-HPV) is the inability of p53 to activate apoptosis due to the effect of the oncoprotein E6. However, the effect of HPV-16 E6 splice variant isoforms (namely E6*I and E6*II), their interaction with the existing p53 isoforms, and their influence on apoptosis is unclear. Here, we report the outcome of ectopic expression of HPV-16 E6, E6*I, and E6*II on the relative levels of p53 and p53 isoforms Δ40p53 and Δ133p53 and their interactions with these proteins. Additionally, we evaluated the effect of ectopic expression of p53, Δ40p53, and Δ133p53 on apoptosis in a p53 null pulmonary cell line (H1299) co-transfected with E6 isoforms and p53^+/+ cell lines with HR-HPV (SiHa and HeLa), transfected with p53 isoforms and treated with cisplatin, a conventional drug used to treat cervical cancer. Our results show that E6 and E6*II induced a significant decrease in p53, but only E6 triggered a Δ40p53 decrease and that E6*II interacts with p53 but not with Δ40p53 and Δ133p53. On the other hand, E6*I did not show any effect or interaction with the p53 isoforms. We found that apoptosis was elevated in H1299 cells transfected with p53 (p = 0.0001) and Δ40p53 (p = 0.0001). A weak apoptotic effect was observed when Δ133p53 was ectopically expressed (p = 0.0195). We observed that both p53 (p = 0.0006) and Δ40p53 (p = 0.0014) induced apoptosis in cisplatin-treated SiHa cells; however in cisplatin-treated HeLa cells, only p53 induced apoptosis (p = 0.0029). No significant differences in apoptosis were observed upon ectopic expression of p53, Δ40p53, and Δ133p53 in SiHa and HeLa cells. Our findings suggest a possible therapeutic application for the combining of p53 or Δ40p53 with cisplatin to induce an increased apoptosis of cancer cells expressing E6 isoforms from HPV-16.

Identification of HPV16’s E6 gene in suspected cases of cervical lesions and docking study of its L1 protein with active components of Echinacea purpurae

Background

HPV 16 is the primary etiologic agent of cervical cancer and the presence of L1 and E6 oncoproteins are largely responsible for its virulence. It was the objective of this study to identify HPV16 isolates from suspected cases of cervical cancer at Specialist Hospital Sokoto and Sir Yahaya Memorail Hospiatal Birnin Kebbi, Nigeria and also to identify potent HPV16's L1 protein inhibitor using in silico analysis.

Methods

A total of 144 cervical samples consisting of 21 low grade squamous intraepithelial lesion, 6 high grade lesion and 117 negative pap smears were collected. The samples were subjected for molecular detection using PCR targeting E6 gene of the virus. Data generated for the molecular prevalence was statistically analyzed using Chi-square method. AutoDock Vina was used to carry out the molecular docking between 2hr5 and Chicoric acid, curcumin and Echinacoside.

Results

Out of the 144 samples, 24 samples were positive for the PCR representing 16.9% molecular prevalence rate. There is statistically significant association between cyto-diagnoses and presence of HPV16 (P < 0.05). Docking analysis showed that the Chicoric acid components of Echinacea purpurae have strong binding affinity (-8.7 kcal/mol) to the L1 protein of the HPV.

Conclusion

This study provides data on HPV 16 epidemiology in northern Nigeria, and also provides novel evidence for consideration on certain interacting residues, when synthesizing Anti-HPV compounds in the wet lab.

Cryo EM Analysis Reveals Inherent Flexibility of Authentic Murine Papillomavirus Capsids

Human papillomavirus (HPV) is a significant health burden and leading cause of virus-induced cancers. However, studies have been hampered due to restricted tropism that makes production and purification of high titer virus problematic. This issue has been overcome by developing alternative HPV production methods such as virus-like particles (VLPs), which are devoid of a native viral genome. Structural studies have been limited in resolution due to the heterogeneity, fragility, and stability of the VLP capsids. The mouse papillomavirus (MmuPV1) presented here has provided the opportunity to study a native papillomavirus in the context of a common laboratory animal. Using cryo EM to solve the structure of MmuPV1, we achieved 3.3 Å resolution with a local symmetry refinement method that defined smaller, symmetry related subparticles. The resulting high-resolution structure allowed us to build the MmuPV1 asymmetric unit for the first time and identify putative L2 density. We also used our program ISECC to quantify capsid flexibility, which revealed that capsomers move as rigid bodies connected by flexible linkers. The MmuPV1 flexibility was comparable to that of a HPV VLP previously characterized. The resulting MmuPV1 structure is a promising step forward in the study of papillomavirus and will provide a framework for continuing biochemical, genetic, and biophysical research for papillomaviruses.

Improvement of RG1-VLP vaccine performance in BALB/c mice by substitution of alhydrogel with the next generation polyphosphazene adjuvant PCEP

Current human papillomavirus (HPV) vaccines provide substantial protection against the most common HPV types responsible for oral and anogenital cancers, but many circulating cancer-causing types remain for which vaccine coverage is lacking. In addition, all current HPV vaccines rely on aluminum salt-based adjuvant formulations that function through unclear mechanisms with few substitutes available. In an effort to expand the toolbox of available adjuvants suitable for HPV vaccines, we compared the immunogenicity of the RG1-VLP (virus-like particle) vaccine in BALB/c mice when formulated with either the aluminum hydroxide adjuvant Alhydrogel or the novel polyphosphazene macromolecular adjuvant poly[di (carboxylatoethylphenoxy) phosphazene] (PCEP). PCEP-formulated RG1-VLPs routinely outperformed VLP/Alhydrogel in several measurements of VLP-specific humoral immunity, including consistent improvements in the magnitude of antibody (Ab) responses to both HPV16-L1 and the L2 RG1 epitope as well as neutralizing titers to HPV16 and cross-neutralization of pseudovirion (PsV) types HPV18 and HPV39. Dose-sparing studies indicated that RG1-VLPs could be reduced in dose by 75% and the presence of PCEP ensured activity comparable to a full VLP dose adjuvanted by Alhydrogel. In addition, levels of HPV16-L1 and -L2-specific Abs were achieved after two vaccinations with PCEP as adjuvant that were equivalent to or greater than levels achieved with three vaccinations with Alhydrogel alone, indicating that the presence of PCEP resulted in accelerated immune responses that could allow for a decreased dose schedule. Given the extensive clinical track record of polyphosphazenes, these data suggest that substitution of alum-based adjuvants with PCEP for the RG1-VLP vaccine could lead to rapid seropositivity requiring fewer boosts, the dose-sparing of commercial VLP-based vaccines, and the establishment of longer-lasting humoral responses to HPV.

Human papillomavirus and prostate cancer: The role of viral expressed proteins in the inhibition of anoikis and induction of metastasis

BACKGROUND

The aim of this study is to address the role of HPV in prostate cancer (PCa) development through the inducement of resistance to anoikis.

METHODS

In this case-control study, prostate tissues and blood samples were collected from 116 individuals, including 72 cases with PCa and 44 non-malignant prostate tissue samples as a control group. The expression level of HPV genes (E2, E6, and E7) and cellular genes including anti-apoptotic mediators (Bcl-2 and survivin), tumor suppressor proteins (Rb and p53), and some mediators involved in anoikis resistance and invasiveness (E-cadherin, N-cadherin, Twist, PTPN13 and SLUG) were evaluated.

RESULTS

HPV genome was identified in 36.1% cases and 15.9% control samples, additionally there was found to be a statistic significant association between the presence of HPV and PCa (OR = 1.64, 95% C.I = 0.8-1.8, P-value = 0.023). HPV genotype 16 and 18 were the most prevalent genotype in both in the PCa group and the control group. The expression level of the tumor suppressor proteins (Rb and p53) and anti-apoptotic mediators (Bcl-2 and Survivin) were significantly decreased and increased, respectively, in the HPV-positive specimens compared to the HPV-negative specimens. Furthermore, the mean expression level of N-cadherin, SLUG, and TWIST in the HPV-positive specimens was higher than HPV-negative specimens while the mean expression level of PTPN-13 and E-cadherin genes in the HPV-positive specimens was lower than HPV-negative specimens.

CONCLUSION

Our study suggests that HPV infection may be involved in the development of PCa metastases by modulating anoikis resistance related genes.

Application Value of Detection of High-Risk HPV Infection in Early Cervical Cancer Patients in Disease Diagnosis and Prognosis Evaluation

BACKGROUND

To analyze the relationship between HPV infection and early cervical cancer and postoperative survival outcomes.

METHODS

A total of 556 women were recruited to receive TCT and HPV tests from October 2017 to October 2018. The type of disease was pathologically diagnosed. The HPV positive rate, HPV-DNA, and E6/E7 mRNA quantitative level were detected, and the diagnostic accuracy of the subjects was analyzed by the receiver operating characteristic (ROC). The cervical intraepithelial neoplasia (CIN) and early cervical cancer patients were radically cured and followed up for 12.0 months to analyze the recurrence rate.

RESULTS

Seventy-two cases of chronic cervicitis, 54 cases of CIN, and 51 cases of cervical cancer patients were pathologically diagnosed (32 cases in early stage and 19 cases in middle and late stage). HPV positive rate increased gradually in chronic cervicitis, CIN, and cervical cancer group (p < 0.001) and HPV 16 + 18 subtype. The positive rate was significantly different (p = 0.009). HPV-DNA and E6/E7 mRNA quantification also showed significant differences (p < 0.001). ROC analysis indicated that the accuracy of HPV-DNA and E6/E7 mRNA quantitative diagnosis of malignant lesions (CIN+ cervical cancer) were 0.865 and 0.879, respectively. There were 4 cases (7.41%) of recurrence in CIN group and 5 cases (15.63%) in early cervical cancer group. There was no difference (p = 0.401) among all of the patients. All patients with recurrence were HPV positive.

CONCLUSIONS

HPV detection is an indispensable screening method for early cervical cancer and precancerous lesions, and comprehensive HPV 16 and 18 subtypes. DNA and E6/E7 mRNA quantification assay would further improve the accuracy of screening.

[Early Mitotic Inhibitor 1 Regulates DNA Re-replication Mediated by Human Papillomavirus Subtype 16 E7 in Response to DNA Damage]

Objective To explore the molecular mechanism of human papillomavirus subtype 16(HPV-16)E7 oncogene-induced DNA re-replication in response to DNA damage. Methods Flow cytometry was performed to examine the cell cycle changes in RPE1 E7 cells stably expressing HPV-16 E7 and its control cell RPE1 Vector after DNA damage.Immunoblotting assay was used to evaluate the early mitotic inhibitor 1(Emi1)expression in RPE1 E7 and RPE1 Vector cells with or without DNA damage.The changes of the proportion of polyploidy was detected by flow cytometry in DNA-damaged RPE1 E7 cells interfered by Emi1 small interfering RNA. Results Compared with the control cells,the proportion of polyploids in RPE1 E7 cells was significantly increased in response to DNA damage(t=6.397,P=0.0031).Emi1 protein expression was significantly increased in DNA damaged RPE1 E7 cells(t=8.241,P=0.0012).The polyploid ratio of RPE1 E7 cells was significantly reduced after Emi1 was interfered by two independent small interfering RNAs(t=2.916,P=0.0434;t=3.452,P=0.0260). Conclusion In response to DNA damage,Emi1 promoted DNA re-replication caused by HPV-16 E7.

FLT3L and granulocyte macrophage colony-stimulating factor enhance the anti-tumor and immune effects of an HPV16 E6/E7 vaccine

HPV16 infections promote the development and progression of cervical cancer. We investigated Fms-like Tyrosine Kinase 3 Ligand and granulocyte macrophage colony-stimulating factor as new adjuvants to an HPV16 vaccine. C57BL/6 mice were immunized by intramuscular injections of HPV16 E6/E7 plasmids every two weeks, three times in all. An in vivo imaging system was used to observe tumor growth and metastasis. Pathological changes to the heart, liver, spleen, lungs, brain and kidneys were recorded, and the survival rate of the mice was determined. The constructed HPV16 E6/E7 vaccine had no notable side effects in terms of physiological or biochemical indexes. Fms-like Tyrosine Kinase 3 Ligand and granulocyte macrophage colony-stimulating factor increased the inhibitory effects of the HPV16 E6/E7 vaccine on tumor growth and metastasis in vivo. The HPV16 E6/E7 vaccine enhanced the survival of mice and increased their serum-specific antibody and interferon-γ levels. Fms-like Tyrosine Kinase 3 Ligand and granulocyte macrophage colony-stimulating factor augmented these effects. In a cytotoxic lymphocyte killing test, Fms-like Tyrosine Kinase 3 Ligand and granulocyte macrophage colony-stimulating factor improved the ability of splenic lymphocytes from HPV16 E6/E7-vaccinated mice to kill B16 cells. As Fms-like Tyrosine Kinase 3 Ligand and granulocyte macrophage colony-stimulating factor enhanced the anti-tumor and immune effects of the HPV16 vaccine, these adjuvants should be considered for the treatment of cervical cancer.

Transcriptome sequencing profiles of cervical cancer tissues and SiHa cells

High-risk human papillomavirus (HPV) is a causal factor for cervical cancer, of which HPV16 is the predominant genotype, but the detailed mechanism remains to be elucidated. In this study, we performed transcriptome sequencing in cervical cancer tissues with HPV16-positive and normal tissues with HPV16-negative, and SiHa cells with or without HPV16 E6/E7 knockdown, and identified 140 differential expressed genes (DEGs) in two data sets. We carried out a series of bioinformatic analyses to learn more about the 140 DEGs, and found that 140 DEGs were mostly enriched in cell cycle and DNA repair through Kyoto Encyclopedia of Genes and Genomes pathway enrichment, Gene Ontology annotation, and gene set enrichment analysis. A total of 20 genes including RMI1, MKI67, FANCB, KIF14, CENPI, RACGAP1, EXO1, KIF4A, FOXM1, C19orf57, PSRC1, NUSAP1, CIT, NDC80, MCM7, GINS2, MCM6, ORC1, TLX2, and UHRF1 were screened by co-expression analysis; of those, the expressions of 6 (CENPI, FANCB, KIF14, ORC1, RACGAP1, and RMI1) were verified by qRT-PCR. Further, we found that E2F family, NF-Y, AhR:Arnt, and KROX family may be involved in modulating DEGs by TransFind prediction. TF2DNA database and co-expression analysis suggested that 12 TFs (ZNF367, TLX2, DEPDC1B, E2F8, ZNF541, EGR2, ZMAT3, HES6, CEBPA, MYBL2, FOXM1, and RAD51) were upstream modulators of DEGs. Our findings may provide a new understanding for effects of HPV oncogenes in the maintenance of cancerous state at the transcriptional level.

Long-distance communication: Looping of human papillomavirus genomes regulates expression of viral oncogenes

High-risk human papillomaviruses (HPVs) are a major cause of cancers. HPVs infect epithelial cells, and viral oncogenes disrupt several cellular processes, including cell division, differentiation, and apoptosis. Expression of these oncogenes is relatively low in undifferentiated epithelial cells but increases in differentiating cells by unknown mechanisms. In a new study, Parish and colleagues unveil how two cellular proteins, CCCTC-binding factor (CTCF) and Yin Yang 1 (YY1), mediate looping of the HPV18 genome, which regulates expression of viral oncogenes in both dividing and differentiating epithelial cells.

This Primer explores the implications of a new study that connects viral DNA-looping and transcription of human papillomavirus oncogenes at different stages of the viral life cycle.

Checkpoint Kinase 1 Is Overexpressed during HPV16-Induced Cervical Carcinogenesis

PURPOSE

Cervical cancer is one of the leading causes of cancer death among women worldwide. Checkpoint kinase 1 (Chk1) has a critical role in DNA damage response and cell cycle checkpoint control. Emerging evidence suggests that Chk1 promotes tumor growth. However, whether Chk1 is important for development of cervical cancer is largely unknown.

METHODS

The levels of Chk1 mRNA expression were determined using quantitative real-time polymerase chain reaction in a panel of 90 cervical specimens, including 30 cervical cancer tissues, 30 CIN II-III, and 30 normal cervical tissues. We investigated the correlation between Chk1 and HPV16 E6/E7 at the mRNA level using another 30 CIN II-III and 32 cervical cancer tissues with HPV16 infection. MTT and cell cycle assays were conducted to show the function role of Chk1 in cervical cancer SiHa cells.

RESULTS

Chk1 was gradually increased during cervical lesion progression and positively correlated with HPV16 E6/E7 expression. Inhibition of Chk1 resulted in suppressed cell proliferation concomitant with the blocking of cell cycle at S-phase in cervical cancer SiHa cells.

CONCLUSIONS

These results indicate that maintained Chk1 expression by HPV16 E6/E7 in cervical cancer cells promotes cell growth by blocking the cell cycle progression, and may point to novel strategies for targeting Chk1 in cancer therapy.

A teat papillomatosis case in a Damascus goat (Shami goat) in Hatay province, Turkey: a new putative papillomavirus?

Papillomaviruses (PVs) are epitheliotropic viruses that cause benign proliferative lesions in the skin (warts or papillomas) and mucous membranes of their natural hosts. Recently, new PVs have been found in many animal species. The most common current approach for identifying novel PV types is based on PCR, using various consensus or degenerated primer (broad-range primers), designed on the basis of the multiple alignment of nucleotide or amino acid sequences of a large number of different human papillomaviruses (HPV). PVs have been classified according to the sequence similarity of one of their capsid proteins, L1, without taking into account other regions of the genome and without considering the phenotypic characteristics of the viral infection. In this study, we performed molecular detection and typing of a PV in a goat with teat papillomatosis. Firstly, PCR was performed using the FAP59/FAP64 and MY09/MY11 primer pairs for the L1 gene region. The PV DNA was found to be positive only with the FAP59/FAP64 primer pair. PV DNA was then tested with three primer sets in four different combinations (L2Bf/FAP64, L2Bf/L1Br, FAP59/FAP64, L1Bf/LCRBr) for the gene region encoding the L1, L2 and LCR proteins. The goat teat papilloma sample was amplified using FAP59/FAP64 primers and two primer pairs (L2Bf/FAP64 and L2Bf/L1Br). We obtained products matching approximately 604 bp of the L1 region of the virus. PV DNA was used for typing using sequence analysis/PCR with some type-specific primers for bovids, caprids and cervids. The results of the sequence analysis suggested one new putative PV type with sequence identity ranging from 46.45 to 80.09% to other known papillomaviruses, including Capra hircus papillomavirus (ChPV-2), bovine papillomavirus (BPV) 6, 7, 10, 11 and 12, Rangifer tarandus papillomavirus 3 (RtPV-3) and BPV-7Z (Alpine wild ruminant papillomavirus; Cervus elaphus papillomavirus). We therefore propose that this is the first identification of a new putative type, MG523274 (HTY-goat-TR2016), in a goat with teat papillomatosis. It is essential to identify PV types in different animal species and investigate their prevalence/distribution and clinical consequences in order to develop appropriate prophylactic and/or therapeutic procedures and to determine the interspecies transmission potential and evolution of PVs.

Hybrid Assembly toward Enhanced Thermal Stability of Virus-like Particles and Antibacterial Activity of Polyoxometalates

In an effort to improve both the stability of virus-like particles (VLPs) and the medical activity of polyoxometalates (POMs), a new hybrid assembly system between human papillomavirus (HPV) capsid protein L1 and a europium-containing POM (EuW₁₀) has been constructed, for the first time, via the electrostatic interactions between them. The co-assembly of EuW₁₀ and HPV 16 L1-pentamer (L1-p) in buffer solution resulted in the encapsulation of POMs in the cavity of VLPs, which was further confirmed by cesium chloride (CsCl) gradient ultracentrifugation, SDS-PAGE, dynamic light scattering, and transmission electron microscopy, whereas the post-assembly of EuW₁₀ with the as-prepared VLPs leads to the adsorption of POMs only on the external surface of particles, and both cases improved the thermal and storage stabilities of VLPs obviously. Particularly, the encapsulation of POMs in VLPs largely improved the antibacterial activity of EuW₁₀, and thereby, the present study will be significant for both the stability improvement of protein vaccines and the development of POM medicine.

Seeing HPV in the New Light Offers a Glimpse of Heparin

In this issue of Structure, Guan et al. (2017) describe cryo-EM mapping of human papillomavirus 16 (HPV16) capsids that propose locations for L2 and heparin binding sites. The high resolution of the modern cryo-EM methods (in this case down to 4.3 Å) opens great opportunities to probe conformational changes that take place during virus-receptor binding.

Crowd Control: E7 Conservation Is the Key to Cancer

Several human papillomavirus type 16 (HPV16) oncoproteins contribute to cellular transformation in vitro. In this issue of Cell, Mirabello and colleagues use high-throughput sequencing data to assess the diversity of HPV16 isolates from human patients. These data suggest that the E7 oncoprotein is the fundamental contributor to in vivo carcinogenesis.

Autophagy regulates UBC9 levels during viral-mediated tumorigenesis

UBC9, the sole E2-conjugating enzyme required for SUMOylation, is a key regulator of essential cellular functions and, as such, is frequently altered in cancers. Along these lines, we recently reported that its expression gradually increases during early stages of human papillomavirus (HPV)-mediated cervical lesions transformation. However, a better understanding of how UBC9 is exploited by transforming viral oncoproteins is still needed. In the present study, we show that in human samples HPV drives UBC9 up-regulation also in very early steps of head and neck tumorigenesis, pointing to the important role for UBC9 in the HPV-mediated carcinogenic program. Moreover, using HPV-infected pre-cancerous tissues and primary human keratinocytes as the natural host of the virus, we investigate the pathological meaning and the cellular mechanisms responsible for UBC9 de-regulation in an oncoviral context. Our results show that UBC9 overexpression is promoted by transforming viral proteins to increase host cells' resistance to apoptosis. In addition, ultrastuctural, pharmacological and genetic approaches crucially unveil that UBC9 is physiologically targeted by autophagy in human cells. However, the presence of HPV E6/E7 oncoproteins negatively impacts the autophagic process through selective inhibition of autophagosome-lysosome fusion, finally leading to p53 dependent UBC9 accumulation during viral-induced cellular transformation. Therefore, our study elucidates how UBC9 is manipulated by HPV oncoproteins, details the physiological mechanism by which UBC9 is degraded in cells, and identifies how HPV E6/E7 impact on autophagy. These findings point to UBC9 and autophagy as novel hallmarks of HPV oncogenesis, and open innovative avenues towards the treatment of HPV-related malignancies.

[HPV E7 Function in DNA Damage Response of Cervical Intraepithelial Neoplasia.]

OBJECTIVES

To determine the function of human papillomavirus (HPV) E7 in DNA damage response of cervical intraepithelial neoplasia (CIN) 3 cells.

METHODS

Samples of CIN 3 and child foreskin tissues were collected,with pathologically confirmed HPV positive and negative,respectively.Collagenase A was used for digesting tissues prior to primary culture.The HPV negative cells were infected with lentivirus E7 and pLV.Proteins(53BP1,NBS1,BRCA1 and RPA32) responsive to DNA double break damages were detected by indirect immunofluorescent staining after 0-8 h treatment with X-ray (2 or 5 Gy).

RESULTS

After treatment with 2 or 5 Gy X-ray,53BP1,NBS1,BRCA1 and RPA32 foci in HPV⁺ cells increased compared with HPV^- cells (P<0.05).Less 53BP1,RPA32,BRCA1 and NBS1 foci positive cells (foci>5) were found in E7 infected cells than in pLV infected cells(P<0.05).Both of them reached the peak at 6 h (2 Gy) or 4 h (5 Gy).

CONCLUSIONS

We have successfully established a model to detect the function of HPV E7 in DNA damage response using primary culture of CIN fibroblasts.With the progression of CIN,HPV E7 can inhibit DNA double break repair.

Aneuploidy and Tetraploidy as Distinct Patterns During Melanomagenesis

Melanoma is characterized by a high degree of chromosome instability (CIN), the loss or gain of entire chromosomes or pieces of chromosomes. Also, CIN is likely to drive the progression of benign melanocytic lesions to malignant tumors, although very little is known about the acquisition of the mechanisms that promote CIN along this progression. Here, we describe the development of a model system to study the progression of melanomagenesis starting with normal human melanocytes followed by inactivation of the p53 and pRb tumor suppressors by addition of the E6/E7 proteins. The cells were then transduced with a growth-promoting, constitutionally-active mutant NRAS. The addition of E6/E7 and E6/E7 NRAS was found to give a growth advantage to the cells compared to normal melanocytes and a statistically significant gain of aneuploidy; aneuploidy was 24.7% in primary melanocytes, 33.8% in E6/E7 melanocytes, and 70.5% in E6/E7 NRAS melanocytes. Further, we found an increase in tetraploid cells in the cell model which was statistically significant between primary melanocytes and E6/E7, NRAS melanocytes. We also observed an increase in aneuploid cells between three population doublings in primary melanocytes, whereas this increase was not seen in the E6/E7 melanocytes. Together, these data demonstrate that this model system utilizing stepwise addition of genetic mutations driving melanomagenesis is a useful tool to study CIN and could even be used to study the mechanisms responsible for these alterations in genetic makeup.

Human Papillomavirus (HPV) and cervical cancer

Cervical cancer is one of the most common cancer in women in Poland and in the world. The main risk factor for this cancer is persistent infection with high - risk human papillomavirus (HPV-HR) types. The most important role in carcinogenesis is attributed to viral oncoproteins E6 and E7, that affect some cell cycle proteins. Diagnosis of HPV infection, in which the molecular test play an important role, allow for detection on precancerous lesions of the cervix, and effective treatment of these conditions. The application of modern diagnostic tests and vaccination against HPV may in the future lead to a reduction in the incidence of cervical cancer.

Effects of Methylation Status of CpG Sites within the HPV16 Long Control Region on HPV16-Positive Head and Neck Cancer Cells

Objective

To map comprehensively the methylation status of the CpG sites within the HPV16 long control region (LCR) in HPV-positive cancer cells, and to explore further the effects of methylation status of HPV16 LCR on cell bioactivity and E6 and E7 expression. In addition, to analyze the methylation status of the LCR in HPV-positive oropharyngeal squamous cell carcinoma (OPSCC) patients.

Methods and Materials

Methylation patterns of HPV16 LCR in UM-SCC47, CaSki, and SiHa cells and HPV16-positiive OPSCC specimens were detected by bisulfite-sequencing PCR and TA cloning. For cells treated with 5-aza-2′-deoxycytidine and E6 and E7 knockdown, MTS and trypan blue staining, annexin-V and 7-AAD staining, and prodidium iodide were used to evaluate cell growth and cell proliferation, cell apoptosis, and cell cycle arrest, respectively. E6 and E7 mRNA and protein expression were analyzed by quantitative real-time PCR and immunocytochemistry, respectively.

Results

Hypermethylation status of the LCR in UM-SCC47 (79.8%) and CaSki cells (90.0%) and unmethylation status of the LCR in SiHa cells (0%) were observed. Upon demethylation, the cells with different methylation levels responded differently during growth, apoptosis, and cell cycle arrest, as well as in terms of their E6 and E7 expression. In HPV16-positive OPSCC patients, the methylation rates were 9.5% in the entire LCR region, 13.9% in the 5′-LCR, 6.0% in the E6 enhancer, and 9.5% in the p97 promoter, and hypermethylation of p97 promoter was found in a subset of cases (20.0%, 2/10).

Conclusions

Our study revealed two different methylation levels of the LCR in HPV16-positive cancer cells and OPSCC patients, which may represent different carcinogenesis mechanisms of HPV-positive cancers cells. Demethylating the meCpGs in HPV16 LCR might be a potential target for a subgroup of HPV16-positive patients with head and neck squamous cell carcinoma.

[Expression of Daxx and HPV16 E6 and its significance in cervical lesions]

OBJECTIVE

To investigate the expression of death domain associated protein (Daxx) and human papillomavirus 16 E6 protein (HPV16 E6) in cervical lesions and analyze their significance.

METHODS

Immunohistochemical SABC method was used to detect the expression of Daxx and HPV16 E6 in 194 cases of cervical tissues with different lesions.

RESULTS

(1) The positive expression rate of Daxx was 28.57% (12/42), 40.00% (18/45), 65.91% (29/44), 66.67% (42/63), respectively, in chronic cervicitis, cervical intraepithelial neoplasia I-II (CIN I-II), CIN III and cervical squamous cell carcinoma. The positive expression rate of HPV16 E6 was 15.38% (6/39), 36.17% (17/47), 46.30% (25/54), 100.00% (24/24) in the above four groups. The positive rates in cervical cancer group and high grade CIN group were significantly higher than these in low level of CIN group and chronic cervicitis group (P<0.05). (2) The expression of Daxx was stronger in HPV16 E6 high positive group than that in HPV16 E6 low positive group (P<0.05). (3) There was no significant relationship between the expression of Daxx and pathological classification, clinical stage, situation of lymph node metastasis or patients' age in cervical squamous cell carcinoma (P>0.05). (4) There was significant positive relationship between Daxx and HPV16 E6 expression (r=0.695, P<0.05).

CONCLUSIONS

The expression of Daxx and HPV16 E6 gradually increases with cervical lesion degree aggravating. Here might be synergy between them, and both could promote the development of cervical lesions.

[Comparative study of HR HPV E6/E7 mRNA and HR-HPV DNA in cervical cancer screening]

OBJECTIVE

To determine the performance of HR-HPV E6/E7 massager RNA (mRNA) test for detecting high-grade cervical intraepithelial neoplasia in cervical cancer screening and compare the clinical performance of HR-HPV E6/E7 mRNA test with HC-2 and Cervista HPV DNA tests for cross-sectional positivity in women with and without cervical neoplasia.

METHODS

A total of 172 women underwent cytology, HR-HPV DNA test, HR-HPV E6/7 mRNA test, colposcopy and biopsy. We compared the clinical performance of HR-HPV E6/E7 mRNA test with Hybrid Capture 2 DNA test (HC-2) and Cervista HR-HPV DNA test on the cervical brush specimens during colposcopy and routine screening. The samples were histologically confirmed high-grade cervical intraepithelial neoplasia (CIN II) or worse (CIN II+) as an endpoint.

RESULTS

HR-HPV E6/E7 mRNA positive rate was 37.9% in NILM, 67.9% in ASCUS and LSIL, 88.5% in ASC-H+. HR-HPV E6/E7 mRNA positive rate was 38.6% in CIN I, 77.4% in CIN II-3 and 92.5% in SCC. HR-HPV E6/E7 mRNA test showed a higher specificity than HC-2 and Cervista HPV DNA tests for high-grade lesions (61.4%, 54.3%, 55.7%, respectively, P < 0.05) and also a higher positive predictive value (75.9%, 74.8%, 74.6% respectively). Among three tests, HR-HPV E6/E7 mRNA had the largest area of ROC curve and the best diagnostic value.

CONCLUSION

HR-HPV E6/E7 mRNA test has a performance more specific for detecting CIN II+ with the same sensitivity as HC-2 and Cervista HPV DNA tests. And it may serve as a more specific test for predicting the risk of progression and offer a viable tool for triage during cervical cancer screening.

Impact of human papillomavirus on oropharyngeal cancer biology and response to therapy: implications for treatment

Oropharyngeal squamous cell carcinoma (OPSCC) originating from human papillomavirus infection has emerged as a new entity in head and neck cancer, defining a subset of patients with distinct carcinogenesis, risk factor profiles, and clinical presentation that show markedly improved survival than patients with classic OPSCC. De-escalation of therapy and identification of relevant biomarkers to aid in patient selection are actively being investigated. This review addresses the implications of these findings in clinical care.

VLPs displaying a single L2 epitope induce broadly cross-neutralizing antibodies against human papillomavirus

Background

Virus-like Particles (VLPs) display can be used to increase the immunogenicity of heterologous antigens. Here, we report the use of a bacteriophage MS2-based VLP display platform to develop a monovalent vaccine targeting a broadly neutralizing epitope in the minor capsid protein human papillomavirus (HPV) that provides broad protection from diverse HPV types in a mouse pseudovirus infection model.

Methodology/Principal Findings

Peptides spanning a previously described cross-neutralizing epitope from HPV type 16 were genetically inserted at the N-terminus of MS2 bacteriophage coat protein. Three of the four recombinant L2-coat proteins assembled into VLPs. L2-VLPs elicited high-titer anti-L2 antibodies in mice, similar to recombinant VLPs that we had previously made in which the L2 peptide was displayed on a surface-exposed loop on VLPs of a related bacteriophage, PP7. Somewhat surprisingly, L2-MS2 VLPs elicited antibodies that were much more broadly cross-reactive with L2 peptides from diverse HPV isolates than L2-PP7 VLPs. Similarly, mice immunized with L2-MS2 VLPs were protected from genital and cutaneous infection by highly diverse HPV pseudovirus types.

Conclusion/Significance

We show that peptides can be displayed in a highly immunogenic fashion at the N-terminus of MS2 coat protein VLPs. A VLP-based vaccine targeting HPV L2 elicits broadly cross-reactive and cross-protective antibodies to heterologous HPV types. L2-VLPs could serve as the basis of a broadly protective second generation HPV vaccine.

[Association between human papilloma virus late 1 protein and cervical neoplasia]

Human papilloma virus (HPV) is believed to be an essential factor for the development of cervical cancer. Early diagnosis and treatment of cervical intraepithelial neoplasia can effectively inhibit the future progression. HPV late 1 protein possesses epitope that can identify and adhere to host cells, and thus may play an important role in HPV infection and cervical carcinogenesis.

[Effect of HPV 16 E5 on E6 and E7 gene induced human immortalized oral epithelial cell]

PURPOSE

To investigate the influence of HPV16 E5 on E6 and E7 gene in human oral immortalized epithelial cells (HIOEC).

METHODS

The pLEGFP-E5 was transferred into HIOEC cell; Deletion mutation expression vectors were constructed and transferred into HIOEC; RT-PCR was used to detect the gene expression in HIOEC; The expression of E6 and E7 mRNA was detected by real time-PCR;Cell proliferation of HIOEC was evaluated by MTT. All statistical analysis was performed by using SPSS 13.0 software package.

RESULTS

The deletion mutation expression vector of E5 was successfully constructed and applied for further experiments; E5 and the deletion mutation genes were transferred into HIOEC successfully; HPV16 E5 promoted cell proliferation of HIOEC and made the increased expression raised of E6 and E7 genes; However, the deletion mutation had no significant effect on HIOEC.

CONCLUSIONS

HPV16 E5 is transferred into HIOEC successfully. E5 may promote cell proliferation and upregulate the mRNA expression of E6 and E7 genes.

[A 1:2 matched case-control study on the interaction of HPV16E6 and HLA-DR9 allele to esophageal cancer in Kazakh ethnicity, Xinjiang]

OBJECTIVE

To evaluate the role and the association between HPV16E6 infection and HLA-DR9 immune-associated gene to esophageal cancer (EC) in Kazakh of Xinjiang, China.

METHODS

A 1:2 matched case-control study was conducted with 63 cases of EC and 126 controls involved. The controls were matched by sex, nationality, area of residence and age within 5-year difference. HPV16E6 and HLA-DR9 allele were identified by PCR-SSP. Interaction was performed to identify risk factors.

RESULTS

HPV16E6 infection and HLA-DR9 allele positive status were the risk factors for EC, with OR values as 2.67 (95%CI: 1.38 - 5.17) and 3.83 (95%CI: 1.48 - 9.96) respectively. The rate of HPV16E6 infection in individuals with HLA-DR9 allele was different from the ones who were HLA-DR9 allele free (chi(2) = 7.57, P = 0.006), with OR value as 5.79 (95%CI: 1.53 - 21.87). In the controls, the rates of HPV16E6 infection were 22.2% and 16.2% among individuals with HLA-DR9 allele atatus as positive or negative, and without statistically significant difference. Interaction analysis showed there was an interaction of HPV16E6 with HLA-DR9 and were higher than the sum of the two factors presented individually.

CONCLUSION

In our study, we found that the HLA-DR9 allele and HPV16E6 infection had a function of synergy in the process of malignant transformation of esophageal epithelial cells, and jointly promoting the occurrence and development of EC.

[Mechanisms of high-risk human papillomavirus-induced cervical carcinogenesis]

Human papillomaviruses (HPVs) are believed to be the primary causal agents for development of pre-neoplastic and malignant lesions of the uterine cervix and high-risk types such as type 16 and 18 are associated with more than 90% of all cervical carcinomas. The E6 and E7 genes of HPVs are thought to play causative roles, since E6 promotes the degradation of p53 through its interaction with E6AP, an E3 ubiquitin ligase, whereas E7 binds to the retinoblastoma protein pRb and disrupts its complex formation with E2F transcription factors. Although prophylactic vaccines have become available, it is still necessary to clarify the mechanisms of HPV-induced carcinogenesis because of the widespread nature of HPV infection. In this article, the mechanisms of high-risk HPV E6 and E7-induced multistep carcinogenesis and recently identified functions of these oncoproteins are reviewed.

[HPV-associated cutaneous lesions]

More than 100 HPV genotypes are presently distinguished by comparing the DNA sequence of the L1 ORF of each HPV. Two important aspects of the nature of this group of heterogeneous viruses are the way in which specific HPV genotypes are associated with distinct clinical and histological morphologies and the way specific HPV genotypes affect distinct anatomical sites. The former is best evidenced by the HPV type specific cytopathic or cytopathogenic effect (CPE), whereas the latter is suggested by the marked preference of each HPV genotype for specific tissues and sites. Recent studies have also suggested that specific HPV genotypes may target epithelial stem cells at specific anatomical sites. HPV type-specific CPE is the central schema when we analyze and understand the HPV-associated diseases. The concept was suggested by the characterization of distinct HPVs from different types of warts: HPV 2/27/57 from common warts, HPV 3/10/28 from flat warts, HPV 6/11 from condyloma acuminatum, and HPV 5/8 from lesions of epidermodysplasia verruciformis (EV). In this paper, I summarize recent advances in HPV study field, especially on HPV-associated cutaneous lesions. These include inclusion warts, HPV-associated epidermoid cysts, HPV type specific activation of melanogenesis, a double infection with HPV 1 and HPV 63 within a single cell, primary target cells and life cycle of the virus, and the identification of novel genes that are associated EV. The HPV-associated cutaneous lesions thus pose important problems to be resolved in virology and human pathology.

A non-variable L1-peptide displays high sensitivity and specificity for detecting women having human papillomavirus-associated cervical lesions

Anti-human papillomavirus (HPV) antibody detection is promising technique for detecting women at risk of suffering cervical cancer, since potentially oncogenic, persistent, long-term HPV-infections elicit an antibody response which is rarely detected in transitory HPV-infection patients. We have identified a non-variable C-terminus L1-peptide, belonging to an alpha-helix surface exposed on L1-protein, specifically recognized by antibodies from HPV-associated cervical lesion patients. This peptide tested against 313 sera presented higher reactivity with antibodies from cervical cancer (OD mean 0.43+/-0.13) or cervical lesion patients (OD mean 0.41+/-0.17) than antibodies from normal cytology patients (OD mean 0.17+/-0.03). High-risk HPV-infected patients presented higher antibody reactivity (OD mean 0.36+/-0.17) than high-risk HPV-non-infected patients (OD mean 0.22+/-0.11). This peptide showed 88.36% sensitivity, 99.39% specificity and 94.21% correct classification of high risk-HPV cervical lesion or cervical cancer patients. This peptide should be taken into account for designing serological screening or diagnostic tests for use in a clinical scenario.

Crystal Structures of Four Types of Human Papillomavirus L1 Capsid Proteins

Human papillomaviruses (HPVs) are known etiologic agents of cervical cancer. Vaccines that contain virus-like particles (VLPs) made of L1 capsid protein from several high risk HPV types have proven to be effective against HPV infections. Raising high levels of neutralizing antibodies against each HPV type is believed to be the primary mechanism of protection, gained by vaccination. Antibodies elicited by a particular HPV type are highly specific to that particular HPV type and show little or no cross-reactivity between HPV types. With an intention to understand the interplay between the L1 structure of different HPV types and the type specificity of neutralizing antibodies, we have prepared the L1 pentamers of four different HPV types, HPV11, HPV16, HPV18, and HPV35. The pentamers only bind the type-specific neutralizing monoclonal antibodies (NmAbs) that are raised against the VLP of the corresponding HPV type, implying that the surface loop structures of the pentamers from each type are distinctive and functionally active as VLPs in terms of antibody binding. We have determined the crystal structures of all four L1 pentamers, and their comparisons revealed characteristic conformational differences of the surface loops that contain the known epitopes for the NmAbs. On the basis of these distinct surface loop structures, we have provided a molecular explanation for the type specificity of NmAbs against HPV infection.

Role of E-cadherin in the induction of apoptosis of HPV16-positive CaSki cervical cancer cells during multicellular tumor spheroid formation

Multicellular tumor spheroids (MCTS) are three dimensional cell culture systems induced by suspension culture. MCTS are widely used in cancer research because of their similarity to solid tumors. CaSki cells are derived from a metastatic cervical cancer containing human papillomavirus 16 (HPV16). Cell death of CaSki cells in MCTS has been previously reported, and our model is used to better characterize the mechanisms of cell death of HPV16-positive keratinocytes. In this study, we found that apoptosis of CaSki cells was induced by suspension culture along with the formation of MCTS after 24 h of incubation. In suspended CaSki cells, monoclonal antibodies blocking E-cadherin function inhibited MCTS formation and suppressed suspension-induced apoptosis in a dose-dependent manner. Western blot for E-cadherin detected upregulation of the authentic 120 kDa band from MCTS of CaSki cells as well as a shorter 100 kDa band. Addition of EGF, whose receptor is known to form a complex with E-cadherin, abrogated apoptosis of suspended CaSki cells in a dose-dependent manner. These findings suggest that E-cadherin-dependent cell-cell contact, directly or indirectly, mediates the signal to undergo apoptosis of CaSki cells during MCTS formation, and thus provides new information on the role of E-cadherin in cervical cancer cell apoptosis.

Expression de c-kit dans les carcinomes nasopharyngés nord africains, corrélations avec l'âge et LMP1

PURPOSE

To determine the level and prognostic significance of c-kit expression in the two age groups of North African nasopharyngeal carcinomas.

PATIENTS AND METHODS

A retrospective study of 99 NPC specimens from Tunisian patients was investigated by immunohistochemistry. Immunohistochemical data were correlated with Epstein-Barr virus LMP1 expression and pathological, clinical and survival parameters.

RESULTS

c-kit was detected in 79% of the cases for patients under 30 years of age (juvenile form) but in only 56% of specimens in patients over 30 years (P=0.039) and was significantly over-expressed for patients with lymph node involvement (P=0.015). LMP1 score was 5.78 (+/-1.84) for c-kit negative tumors compared to 8,23 (+/-2.39) for c-kit positive tumors (P=0.002). Multivariate analysis including age, lymph nodes involvement and LMP1 expression as co-variables, showed that only age (P=0.027) and LMP1 expression (P=0.005) were significantly correlated to the c-kit expression.

CONCLUSION

c-kit is highly expressed in the juvenile form of North African nasopharyngeal carcinomas. There is a significant association between LMP1 and c-kit expression. The contrasted levels of C-kit expression in the two age groups strengthen the hypothesis that these clinical forms result from distinct oncogenic mechanisms.

Bovine papillomavirus type-2 DNA and expression of E5 and E7 oncoproteins in vascular tumours of the urinary bladder in cattle

Cattles suffering from chronic enzootic haematuria frequently develop urinary bladder tumours of both epithelial and mesenchymal origin mainly haemangioma and its malignant counterpart. The role of the bovine papillomavirus type-2 (BPV-2) and of its major transforming oncoprotein in naturally occurring urothelial carcinogenesis has been recently clarified. E5 interacts in vivo as in vitro with the beta receptor for the platelet-derived growth factor (PDGF). However, studies regarding tumours of mesenchymal origin such as those arising from blood vessels are lacking. We show that the BPV-2 is present in 100% of the vascular tumours of the urinary bladder examined. Twenty-six out of twenty-seven tumour samples (96%) expressed E5 while 20 out of 27 (74%) tumour samples expressed E7. The two viral oncoproteins were not expressed in normal endothelial cells. Additionally, they co-localize in neoplastic endothelial cells as demonstrated by confocal immunofluorescence. PDGFbeta receptor was also shown to be expressed and co-localizes with E5 in neoplastic blood vessels. Our results demonstrate, for the first time, that the BPV-2 is present in high percentage in tumours of mesenchymal origin arising in its natural host. Furthermore, the expression of the two viral oncoproteins confirm that the virus may have a causative role in the neoplastic process.

Differential expression of periodontal ligament-specific markers and osteogenic differentiation in human papilloma virus 16-immortalized human gingival fibroblasts and periodontal ligament cells

BACKGROUND AND OBJECTIVE

Periodontal ligament cells and gingival fibroblasts are important in the remodeling of periodontal tissue, but human papilloma virus (HPV)16-immortalized cell lines derived from human periodontal ligament cells and gingival fibroblasts has not been characterized. The purpose of this study was to establish and differentially characterize the immortalized cell lines from gingival fibroblasts and periodontal ligament by HPV16 transfection.

MATERIAL AND METHODS

Cell growth, cell cycle analysis, western blot for cell cycle regulatory proteins and osteogenic differentiation markers, and reverse transcription-polymerase chain reaction for periodontal ligament-specific markers were performed.

RESULTS

Both immortalized cell lines (immortalized gingival fibroblasts and immortalized periodontal ligament cells) grew faster than primary cultured gingival fibroblasts or periodontal ligament cells. Immortalized gingival fibroblasts and immortalized periodontal ligament cells overexpressed proteins p16 and p21, and exhibited degradation of proteins pRb and p53, which normally cause cell cycle arrest in G2/M-phase. Western blotting and reverse transcription-polymerase chain reaction for periodontal ligament-specific and osteogenic differentiation marker studies demonstrated that a cell line, designated IPDL, mimicked periodontal ligament gene expression for alkaline phosphatase, osteonectin, osteopontin, bone sialoprotein, bone morphogenic protein-2, periostin, S-100A4 and PDLs17.

CONCLUSION

These results indicate that IPDL and immortalized gingival fibroblast cell lines consistently retain normal periodontal ligament and gingival fibroblast phenotypes, respectively, and periodontal ligament markers and osteogenic differentiation in IPDL are distinct from immortalized gingival fibroblast cells.

Characterization of HLA-A2-restricted HPV-16 E7-specific CD8(+) T-cell immune responses induced by DNA vaccines in HLA-A2 transgenic mice

We have recently demonstrated that linkage of DNA-encoding calreticulin to DNA-encoding human papillomavirus-16 E7 antigen strongly enhances the efficacy of DNA vaccines against E7-expressing tumors in animal models. In this study, as a prelude to clinical translation, we characterized the ability of DNA-encoding calreticulin linked to DNA-encoding E7 antigen to generate HLA-A2-restricted E7-specific CD8(+) T-cell responses in HLA-A2 (AAD) transgenic mice, as well as antitumor effects against an E7(+) HLA-A2(+) tumor cell line, TC-1/A2. Our results show that while vaccination with CRT/E7 DNA generates strong H-2D(b)-restricted E7 (amino acid (aa)49-57)-specific CD8(+) T-cell immune responses in both C57BL/6 and HLA-A2 (AAD) transgenic mice, no such responses were generated to HLA-A2-restricted epitopes in either type of mouse. In contrast, vaccination with DNA-encoding calreticulin linked to DNA encoding a mutant version of E7 with a deleted aa49-57 epitope leads to the generation of an HLA-A2-restricted E7 (aa11-20)-specific CTL response in HLA-A2 (AAD) transgenic mice. More importantly, vaccination with CRT/mtE7 (del aa49-57) DNA protects against a lethal challenge with TC-1/A2 tumor cells in HLA-A2 (AAD) transgenic mice. Furthermore, our in vitro studies demonstrate that the presence of the E7 (aa49-57) epitope does not suppress presentation of the HLA-A2-restricted E7 (aa11-20) epitope through MHC class I molecules. Thus, the predominant E7 aa49-57-specific CD8+ T-cell immune response in HLA-A2 transgenic mice vaccinated with CRT/E7 is likely due to preferred expansion of E7 aa49-57-specific CD8(+) T cells in vaccinated mice. These results highlight the importance of epitope immunodominance in the evaluation of immune responses in HLA-A2 (AAD) transgenic mice.