PMPA and PMEA prodrugs for the treatment of HIV infections and human papillomavirus (HPV) associated neoplasia and cancer

The synthesis and in vitro biological evaluation of novel phosphonamidate and phosphonodiamidate prodrugs of adefovir and tenofovir are reported. The selected synthetic approach from free phosphonic acid via bis-trimethylsilyl ester intermediates affords (l)-alanine ester derivatives in 10–70% yields. When assessed for their anti-HIV activity, all the prodrugs showed submicromolar activity. Noteworthy, the most potent derivative in the adefovir series contained a 5,6,7,8-tetrahydronaphtyl group, herein reported for the first time as an aryl moiety in a ProTide. A pronounced cytostatic activity of the above prodrugs is also reported. Selected compounds were tested for their antiproliferative activity against HPV-transformed cells and they were found significantly more active in comparison to their parent compounds. In this study a slightly improved activity of the adefovir derivatives over those of tenofovir was also noticed. However, no specificity for naturally HPV-transformed cell lines was observed

Human papillomavirus-associated head and neck cancer: oncogenic mechanisms, epidemiology and clinical behaviour

Human papillomavirus (HPV) is best known as the underlying cause of cervical squamous cell carcinomas and most cervical adenocarcinomas. Recently however, HPV has been implicated in the development of increasing numbers of oropharyngeal squamous cell carcinomas (OPSCC). This review begins by describing the basic biology of HPV-associated cellular proliferation and the ways in which this proliferation can become unregulated. It also considers points of difference between cervical and oropharyngeal neoplasia. The incidence of HPV associated oropharyngeal cancers has increased dramatically over recent decades and HPV-positive now outnumber HPV negative OPSCC in many developed countries. The epidemiology of HPV-positive OPSCC will be reviewed, in conjunction with the demographics and risk factors. Patients with HPV-positive OPSCC enjoy significantly better prognosis than patients with HPV-negative OPSCC, and treatment regimes specific to HPV-positive are being evaluated. This demonstrates the importance of correct recognition and diagnosis of HPV-positive tumours. The clinical behaviour of HPV-positive OPSCC will be described and current clinical trials summarised. HPV is primarily a sexually transmitted infection, and the implications of this for patients and their families may need to be explored. The penultimate section focuses on the information needs of patients with HPV-positive OPSCC. Primary and secondary prevention have been highly effective in reducing the incidence of cervical cancers. The final section discusses the potential of prophylactic vaccination and screening to prevent HPV-associated OPSCC

The changing aetiology of head and neck cancer: the role of human papillomavirus

Human papillomavirus (HPV) is associated with the development of a subset of head and neck cancers arising in the oropharynx, which includes the tonsils, base of tongue and soft palate. HPV-associated oropharyngeal cancer (OPC) seems to be rapidly increasing in incidence in many countries, including the USA, Sweden and Greece, and is known to affect younger patients who are less likely to have been exposed to the carcinogenic effects of tobacco and alcohol than their HPV-negative counterparts. There is accumulating evidence from prospective studies that HPV-positive OPC responds better to treatment, including chemotherapy and radiotherapy, than HPV-negative OPC, and that patients with HPV-positive disease have excellent long-term survival rates. To date, patients with HPV-positive and HPV-negative OPC are managed according to common treatment protocols; this may no longer be appropriate in an age when the delivery of targeted treatment, tailored to individual tumour and patient characteristics, is becoming a reality. This review summarises our current understanding of HPV-positive OPC, drawing parallels from the role of HPV in the development of cervical cancer. We also consider how knowledge of tumour HPV status may affect the future management and prevention of OPC and discuss the need for future collaborative trials in this important group of patients

Recovery of human papillomavirus nucleic acids from liquid-based cytology media

Residual material from liquid-based cytology (LBC) samples, collected during cervical screening, is a valuable resource for molecular biological analysis. Because of the central role played by human papillomavirus (HPV) in the development of cervical cancer, assays are being developed to quantify HPV gene expression in LBC material. Using quantitative realtime PCR we have compared recovery of HPV DNA and RNA from two of the most widely used LBC systems (the ThinPrep system (Cytyc Corp.) and the SurePath system (TriPath Imaging, Inc.)). Recovery of RNA was unaffected by storage in ThinPrep media, however storage of cells in SurePath resulted in significantly reduced yields (between 10(4)- and 10(8)-fold reduction depending on extraction technique). Given the increasing prominence and importance of molecular diagnostics and prognostics this is an important finding, and must be considered in relation to choice of LBC system

Will vaccination against human papillomavirus prevent eye disease? A review of the evidence

The role of human papillomavirus (HPV) infection in eye disease is controversial. However, a recent case illustrates the possible role of HPV in conjunctival squamous carcinoma and the potentially devastating effects of this disease. The development of two vaccines to prevent infection with HPV types most commonly associated with anogenital cancers has led to debate about the pros and cons of a national immunisation programme to prevent cervical cancer. The introduction of such a vaccination programme may have an additional beneficial effect on the occurrence of some head and neck, including ocular, cancers. This review discusses the nature of papillomaviruses, mechanisms of infection and carcinogenesis, the possible role of HPV in eye disease, and finally the likely impact of the new prophylactic vaccines

Comparison of the PapilloCheck® DNA micro-array human papillomavirus detection assay with hybrid capture II and PCR-enzyme immunoassay using the GP5/6+ primer set

Background Cervical screening detects precancerous cells and routine screening could be improved by testing for Human Papillomavirus (HPV), the virus that causes cervical cancer. HPV infection is common and the benefit of HPV testing would be identification of women who are HPV negative and at low risk of developing cancer. Study design The aim of this study was to evaluate the Greiner Bio-one PapilloCheck® micro-array assay (PapilloCheck) for detection of HPV in comparison with Hybrid Capture II (hc2) and PCR-enzyme immunoassay (PCR-EIA) using the GP5/6+ primers. Results Samples from a cytologically defined population (n = 878) were analysed and 187 samples also had histology information. Overall, 674 out of 878 samples gave a consistent result (76.8%; 95% CI 73.83–79.52%) on all three platforms. The genotype results obtained by PapilloCheck and PCR-EIA were compared and 94% were consistent (95% CI 92.1–96.4%). The main difference was the poor Kappa agreement for detection of high risk (HR) type 35 (Kappa = 0.190) with all inconsistent results being HR positive by PCR-EIA assay but negative on the PapilloCheck platform. There was no statistically significant difference between the performance of each assay when HR HPV positive samples were linked with clinical result (cytology and histology grade). PapilloCheck detected the highest number of HR HPV infections in samples with histology confirmed as CIN1, CIN2 and CIN 3 (76.6%, 85% and 91.7%, respectively). Conclusions Overall, PapilloCheck proved to be a sensitive, reproducible, robust molecular assay for HPV genotyping with the potential for high throughput of specimens in a clinical setting

The potential impact of human papillomavirus vaccination in contemporary cytologically screened populations may be underestimated: an observational retrospective analysis of invasive cervical cancers

The aim of this study was to determine the proportion of invasive cervical cancers attributable to human papillomavirus (HPV) types 16 and 18 in a contemporary, cytologically well-screened UK population. This was achieved in a retrospective observational analysis by HPV typing 453 archival invasive cervical cancers diagnosed between January 1, 2000 and September 1, 2006. Pathological material was collected from 9 hospitals across Wales (UK), and HPV typing and pathology review was conducted at a central laboratory. Genotyping for high-risk HPV DNA was performed by PCR-enzyme immunoassay using the GP5+/6+ primer set. DNA was successfully extracted from 297 cases. Two hundred and eighty cases were included in the final analysis. The proportion of cases which had only HPV 16 and/or 18 was 219 of 280 (78.2%, 95% CI = 73.0–82.7); the proportion of cases which had HPV 16 or 18 and another HPV type was 230 of 280 (82.1%, 95% CI = 77.2–86.2). The proportion of cervical cancers associated with infection with HPV types 16 and 18 has previously been estimated at around 70%. The appropriate figure for a cytologically well-screened UK population appears to be approximately 80%. Hence, the potential impact of the current vaccination programme may be underestimated

Human papillomavirus type 16 L1/L2 DNA methylation shows weak association with cervical disease grade in young women

Background Persistent infection with human papillomavirus (HPV) type 16 causes the majority of cervical cancers. Genital HPV infection is very common, but neoplastic progression is uncommon. There is an urgent need for biomarkers associated with cervical neoplasia, to enable triage of women who test positive for HPV. Objectives To assess the ability of quantitative measurement of HPV16 DNA methylation to separate samples of different cytological and histological grades from young women, among whom rates of HPV infection are high. Study design DNA methylation was quantified by pyrosequencing of bisulphite converted DNA from liquid based cytology samples from 234 women (mean age 20.6 years) who tested positive for HPV16 and showed varying degrees of neoplasia. Methylation was assessed at CpGs in the HPV E2 and L1/L2 regions. Results The performance of methylation-based classifiers was assessed by ROC curve analyses. The best combination of CpGs (5600 and 5609) achieved AUCs of 0.656 (95% CI = 0.520–0.792) for separation of cytologically normal and severely dyskaryotic samples, and 0.639 (95% CI = 0.547–0.731) for separation of samples with or without high-grade neoplasia (CIN2+/−). Conclusions The data are consistent with HPV L1/L2 methylation being a marker of the duration of infection in a specific host. Assessment of HPV DNA methylation is hence a promising biomarker to triage HPV-positive cytology samples, but may have limited utility in young women. Future studies assessing the likely utility of HPV DNA methylation as a potential triage biomarker must take account of women’s age

Decreased HPV-specific T cell responses and accumulation of immunosuppressive influences in oropharyngeal cancer patients following radical therapy

Oropharyngeal cancer (OPC) is a type of squamous cell head and neck cancer that is often associated with human papillomavirus (HPV) infection, suggesting the potential for immunotherapeutic targeting of HPV antigens. This study aimed to determine the effect of radical therapy on HPV-specific T cells and other immune parameters in 20 OPC patients, as a prelude to future immunotherapy studies. HPV DNA could be detected in 9/12 available tissue samples (8/9 HPV+ samples were also p16+). HPV-specific T cell responses against HPV16 E6 and E7 peptides were detected by enzyme-linked immunoSPOT in 10/13 and 8/13 evaluable patients, respectively, but did not appear to correlate with HPV status. Post-treatment, both HPV E6 and E7 T cell responses were decreased (4/13 and 2/13 patients, respectively). These reductions in T cell response could not be explained by a concurrent decrease in memory T cells whose absolute numbers were relatively unaffected by radical therapy (27,975 vs. 25,661/105 PBMC) despite a significant decrease in overall lymphocyte counts (1.74 vs. 0.69 × 109/L). Instead, there were significant increases in regulatory T cells (3.7 vs. 6.8 %) and a population of myeloid-derived suppressor cells (CD14−HLA-DR−CD15hi, 12.38 vs. 21.92 %). This suggests that immunosuppression may contribute to the reduction in HPV-specific T cell responses post-treatment, although study of larger patient cohorts will be required to test whether this affects clinical outcome. Overall these findings suggest that HPV-targeted immunotherapy in post-therapy OPC patients will require multiple strategies to boost T cell immunity and to overcome the influence of immunosuppressive cells