Human Papillomavirus Biology Research Articles

HPV – oral, pharyngeal and laryngeal infections

Human papillomaviruses (HPVs) play an important role in the development of benign and malignant hyperproliferative lesions in the genital and head and neck regions. For many years the main focus of discussion in HPV infections has been the malignant progression of anogenital lesions. We feel that it is now appropriate to assemble and discuss current knowledge of HPV infections in the oral, pharyngeal and laryngeal cavities, which is the reason why we have addressed this topic in the APMIS special issue of 2010. The series of contributions to this volume has been written by top scientists and clinicians working in the field who are faced with the daily challenge of treating patients with these devastating infections. The special issue on ‘HPV – oral, pharyngeal and laryngeal infections’ has seven chapters covering the molecular biology of HPV and basic knowledge of the natural history of the virus during infection of the mucosal epithelia as well as the current knowledge on the epidemiology, immunology and cancer development related to HPV infections in the head and neck regions. The seven chapters are arranged in a sequence with the intention of keeping the flow of information as described above. Therefore, the first chapter describes the molecular biology of HPV infections in an extensive review by Louise T. Chow, Thomas R. Broker and Bettie M. Steinberg. The second chapter by Daniel A. Larson and Craig S. Derkay introduces the reader to the history and epidemiology of one of the devastating diseases. The chapter written by Vincent R. Bonagura et al. unveils the special characteristics of the complex immune response to HPV infection in the tissue and presents to the reader a new model for a possible polarized immune response as involved in disease progression. The molecular mechanisms of the HPV protein functions and their interaction with cell division and signalling – sometimes leading to malignant transformation – are reviewed by David Pim and Lawrence Banks. There are two chapters addressing special infections and cancers caused by HPV. Stina Syrjanen reviews the current knowledge on oral infections in children. Christel B. Laier and Christian von Buchwald address squamous cell carcinomas of the head and neck (HNSCC) in an updated review. The last chapter by Peter J.F. Snijders, Danielle A.M. Heideman and Chris J.L.M. Meijer gives an overview of the molecular techniques used for diagnostic purposes and for identification of individual HPV types present in infected tissue. We are very grateful to our colleagues for taking their valuable time to contribute to the present special issue of APMIS and hope our readers will find it useful and inspiring to have the updated information on ‘HPV – oral, pharyngeal and laryngeal infections’ gathered in this book. APMIS 118: 421 2010 The Authors Journal Compilation 2010 APMIS DOI 10.1111/j.1600-0463.2010.02622.x

Global cooperation in gynecologic cancer

Global cooperation in gynecologic cancer

Epithelial maturation and molecular biology of oral HPV

Human papillomavirus (HPV) is widespread and can cause latent infection in basal cells, with low HPV DNA copy-number insufficient for transmission of infection; can cause subclinical infection that is active but without clinical signs; or can cause clinical infection leading to benign, potentially malignant or malignant lesions. The HPV cycle is influenced by the stage of maturation of the infected keratinocytes, and the production of virions is restricted to the post-mitotic suprabasal epithelial cells where all the virus genes are expressed.Low-risk HPV genotypes are associated with the development of benign oral lesions, whereas high-risk HPV genotypes are implicated in the development of malignant epithelial neoplasms. The rôle of high-risk HPV as a causative agent in epithelial malignancy is different at different anatomical sites: it is almost invariably implicated in squamous cell carcinoma of the uterine cervix, fairly frequently implicated in squamous cell carcinoma of the oropharynx, and it is seldom implicated in squamous cell carcinoma of the mouth.

Human papillomavirus vaccine: a paradigm shift for pediatricians

Recommendations for human papillomavirus (HPV) vaccination during adolescence primarily for a disease, cancer, that occurs only during adulthood is a paradigm shift for pediatricians. Additional postlicensure data and guidelines about HPV biology and epidemiology, disease association, adverse effects, vaccination during pregnancy, and cost-benefit analyses are now available to inform pediatricians and guide HPV vaccination recommendations. The prespecified, end-of-study combined analysis of HPV vaccine efficacy studies for prevention of cervical cancer, and now also for prevention of vulvar and vaginal cancers, confirmed 98-100% vaccine efficacy. Postlicensure surveillance identified a new association of vaccine administration with syncope, and provides assurance of the safety of inadvertent vaccination during pregnancy. Several cost-effectiveness analyses consistently demonstrated that HPV vaccination of 12-year-old girls and catch-up vaccination through 18 years of age, and possibly to 26 years of age, is cost-effective, although the thresholds of affordability vary by study. The downward trend in age of initial HPV infection and the need to educate parents and patients about HPV disease and vaccination underscore the essential role of pediatricians in managing HPV illness. It is critical for pediatricians to thoroughly understand HPV biology and disease and champion HPV vaccination to prevent cervical, vulvar, and vaginal cancers, even though these benefits accrue during adulthood and will likely require 2-4 decades to realize the financial and public health benefits. Several new developments are expected in the near future, including licensure for use in boys and men and the approval of a second, bivalent HPV vaccine.

Vaccines against Human Papillomaviruses - A Major Breakthrough in Cancer Prevention

Carcinoma of the cervix (CaCer) is the second most frequent malignancy in women on a global scale. Epidemiological studies carried out at the beginning of the second half of the 20th century showed that CaCer was of infectious nature and that its agent was transmitted by sexual intercourse. For some 15 years, herpes simplex virus type 2 (HSV2), the genital herpes virus, was suspected to be the etiological agent. This hypothesis was disproved just in the time when the first convincing evidence that the agents of the disease were human papillomaviruses (HPVs) was produced. Copious new findings obtained during the 1980's and 1990's unequivocally confirmed that HPVs were the causative agents. The most dangerous among the over 100 HPV types are types 16 and 18, which together account for over 70% of CaCer cases and very likely also for most of the other malignancies of the anogenital region and the oropharynx. Extensive research of the HPV biology and immunology enabled the development of vaccines based on the s.c. virus-like particles (VLP) prepared by genetic engineering. At present, there is one HPV vaccine on the market; it contains, besides types 16 and 18, also types 6 and 11, the causative agents of certain benign tumours of the genital area and of the larynx. A new vaccine, comprising types 16 and 18 only, the product of another firm, is to appear on the market soon. Both vaccines have already been tested in extensive clinical trials. They are nearly 100% effective, only very weakly reactogenic and they undoubtedly belong among the most perfect vaccines ever produced. The darker side of the anti-HPV vaccines is their high price, the fact that the highest benefits they bring will only become evident in 20 or 30 years, and that they do not afford protection against all oncogenic HPVs. It is therefore imperative that organized cytological screening be continued: it is destined to remain the main instrument of CaCer prevention for several decades. With all probability also other types of vaccine are under development, viz. VLP-based vaccines, whose range of applicability will be wider than that of the present preventive vaccines, as well as vaccines that will, hopefully, be able to inhibit already progressing infection or will be utilizable in CaCer immunotherapy.

Human Papillomavirus-Induced Lesions of the Cervix

Human papillomavirus (HPV) has been well established as a causative agent in cervical carcinoma as well as in squamous intraepithelial lesions (SIL). Morphologic grading of the HPV-associated lesion guides treatment and should ideally reflect the molecular biology of HPV, including the episomal or integrated physical status of the virus.

Chapter 9: Role of mucosal human papillomavirus in nongenital cancers.

Established associations between human papillomavirus (HPV) and lower genital tract cancers provide a framework from which to evaluate a possible pathogenic role for the virus in cancers at nongenital sites. Proposed associations must fit coherently within the context of our current knowledge of the epidemiology and biology of HPV. In this article, insights obtained from studies of the etiologic link between mucosal-type HPV infection and four specific human cancers are described briefly. Specific characteristics, shared among cancers caused by HPV, are then used by extrapolation to discuss possible associations between certain other nongenital cancers and mucosal HPV infections in a manner intended to supplement, and in no way to supplant, the classic Hill criteria for causal inference.

Infectious human papillomavirus type 31b: purification and infection of an immortalized human keratinocyte cell line.

Human papillomaviruses (HPVs) are aetiological agents of human malignancies, most notably cervical cancers. The life-cycles of HPVs are dependent on epithelial differentiation, and this has impeded many basic studies of HPV biology. The organotypic (raft) culture system supports epithelial differentiation such that infectious virions are synthesized in raft tissues from epithelial cells that replicate extrachromosomal HPV genomes. The CIN-612 9E cell line maintains episomal copies of HPV type 31b (HPV31b), an HPV type associated with cervical cancers. Many previous studies, including our own, have focused on characterizing the later stages of the HPV31b life-cycle in CIN-612 9E raft tissues. In this study, we have used the raft system to generate large numbers of HPV31b viral DNA (vDNA)-containing particles. We found a biologically contained homogenization system to be efficient at virion extraction from raft epithelial tissues. We also determined that vDNA-containing particles could be directly quantified from density-gradient fractions. Using an RT-PCR assay, the presence of newly synthesized, spliced HPV31b transcripts was detected following HPV31b infection of the immortalized HaCaT epithelial cell line. Spliced E6 and E1( wedge )E4 RNAs were detected using a single round of RT-PCR from cells infected with a dose as low as 1.0 vDNA-containing particle per cell. Spliced E1*I,E2 transcripts were found in cells infected with an HPV31b dose as low as 10 vDNA-containing particles per cell. Infectivity was blocked by HPV31 antiserum, but was not affected by DNase I. This work lays a foundation for a detailed analysis of the early events in HPV infection.

Human papillomavirus and cervical cancer

Cervical cancer is the second most common cancer in women worldwide. The major risk factor for the development of cervical cancer is infection with certain high-risk types of human papillomavirus (HPV). This report reviews the biology of HPV, presents a model for HPV in the pathogenesis of cervical cancer, and reviews conventional as well as molecular methods for the detection of cervical HPV infections. The role of HPV DNA testing in the management of women with an atypical Pap smear result will also be discussed.

Prophylactic and therapeutic vaccines for genital papillomavirus infection.

The development of potential therapeutic and prophylactic vaccines for human papillomavirus (HPV) infection is a very exciting area of HPV research. There are a number of features of HPV biology that makes the development of a vaccine particularly difficult, although there are several examples of vaccines that have had spectacular success in the prevention of other viral diseases. Our poor understanding of the immune response to HPV infection is the first problem. We do not understand the mechanism by which spontaneous clearing of warts is generated and therefore cannot particularly target this pathway in the development of a vaccine. Furthermore, there is no in vitro culture system nor an animal model for HPV. Another problem is that there is no ready source of live virus that might be exploited for a live attenuated viral vaccine, such as was used with poliovirus. Although most other viruses spend a portion of their life cycle in the systemic circulation where they are vulnerable to neutralizing antibodies, HPV remain exclusively in the epithelium and thus antibodies must transverse the basement membrane and reach the other layers of the skin or mucosa to be effective in preventing infection. Significant progress is being made in the development of potential vaccine candidates despite these and other confounding factors.

Display of complete life cycle of human papillomavirus type 16 in cultured placental trophoblasts.

Human papillomavirus (HPV) infection is threefold more prevalent in spontaneous abortion specimens compared to elective abortions preferentially targeting the placental trophoblasts in these specimens. Here by using infectious ceplar and Southern blot analysis, we demonstrate that the transfected HPV-16 genome de novo replicates in 3A trophoblasts in culture. Peak DNA replication occurred 9-24 days posttransfection, showing classic DNA forms I, II, and III and an 8-kb monomer band upon DpnI/BamHI digestion. Reverse transcription-polymerase chain reaction (RT-PCR) analysis of mRNA expression revealed that E6 and E2 were significantly expressed by day 9, coinciding with HPV-16 DNA replication. However, significant L1 expression was delayed until day 18. L1 protein expression on day 18, but not day 9, was also confirmed by Western blot analysis. The production of HPV-16 virions was demonstrated by three techniques: the appearance of HPV-16 infectious units coinciding with L1 expression, the neutralization of these infectious units with known neutralizing anti-HPV-16 antibodies, and the appearance of spliced E1-E4 and E6-E7 transcripts (RT-PCR) in normal keratinocyte rafts infected with these trophoblast-produced HPV-16 infectious units. These data suggest that HPV-16 is carrying out its complete life cycle in trophoblasts. Previously, HPVs were known to productively replicate only in differentiating keratinocytes of skin. These findings expand HPV biology, support the hypothesis of a possible link between HPV and some spontaneous abortions, and present a new technology for studying HPV.

Potential drugs against cervical cancer: zinc-ejecting inhibitors of the human papillomavirus type 16 E6 oncoprotein.

The principal agent in the etiology of cervical cancer, i.e., human papillomavirus (HPV) type 16, encodes three oncoproteins, E5, E6, and E7. Structural and mutational studies have identified two potential zinc-finger domains as critical for E6 protein function. We investigated several assays to identify and characterize compounds that interfere with the binding of zinc to E6. Thirty-six compounds were selected on the basis of their structure, which would facilitate their participation in sulfhydryl residue-specific redox reactions, and were tested for their ability to release zinc from E6 protein. The zinc-ejecting compounds were then tested for their ability to inhibit E6 binding to E6-associated protein (E6AP) and E6-binding protein (E6BP), two coactivators of E6-mediated cellular transformation. The binding of E6 to E6BP and E6AP was measured by use of surface plasmon resonance (a technique that monitors molecular interactions by measuring changes in refractive index) and by use of in vitro translation assays. The compounds were also tested for their effects on the viability of HPV-containing cell lines. Nine of the 36 tested compounds ejected zinc from E6. Two of the nine compounds inhibited the interaction of E6 with E6AP and E6BP, and one of these two, 4, 4'-dithiodimorpholine, selectively inhibited cell viability and induced higher levels of p53 protein (associated with the induction of apoptosis [programmed cell death]) in tumorigenic HPV-containing cells. We have described assay systems to identify compounds, such as 4,4'-dithiodimorpholine, that can potentially interfere with the biology and pathology of HPV. These assay systems may be useful in the development of drugs against cervical cancer, genital warts, and asymptomatic infections by genital HPVs.

Human papillomavirus and head and neck cancer: epidemiology and molecular biology.

Human papillomaviruses (HPV) are known to cause cancers of the cervix and other anogenital tract sites. Molecular biology has provided some evidence as to the specific mechanisms involved in the HPV-related carcinogenesis. Epidemiologic and molecular biology studies have also suggested that HPV infection may be associated with cancers of the head and neck. This review summarizes the biology of HPV and its potential etiologic role in head and neck cancer. Published reports were used to determine the prevalence of HPV in benign, precancerous, and neoplastic lesions of the oral cavity, pharynx, and larynx. The prevalence was also examined by head and neck site, HPV type, and method of HPV detection. In addition, the occurrence of HPV in normal head and neck tissue, epidemiologic factors related to HPV infection, and clinical implications are discussed. Overall, the frequency of HPV in benign and precancerous lesions ranged from 18.5% to 35.9%, depending upon the detection methodology. Based upon the most sensitive method of detection, polymerase chain reaction (PCR), the overall prevalence of HPV in head and neck tumors was 34.5% (416 of 1205 tumors). The majority of HPV-positive tumors contained the "high risk" HPV types 16 (40.0%) and 18 (11.9%). Among head and neck sites, HPV was most often detected in tumors of the oral cavity (59%), followed by the pharynx (43%), and larynx (33%). The frequency of HPV positivity in oral samples from healthy individuals ranged from 1% to 60%. A limited number of descriptive and analytic epidemiologic studies have indicated that age (<60 years) and sex (male) were associated with the presence of HPV in the tumor, whereas tobacco and alcohol use were not. The relationship between HPV and survival is unclear, with few comprehensive studies currently available. The prevalence of HPV, particularly the high-risk types, suggests a potential etiologic role for the virus in head and neck cancer. Molecular biology has provided important data on the interaction of the HPV oncoproteins with genes important in cell cycle control. Nonetheless, more basic research is needed to describe the physical state of the virus in a variety of cell types and the interaction with other genes. In addition, epidemiologic research is required to further understand the association between HPV and demographic and other risk factors as well as possible routes of transmission. Finally, much work is warranted to provide a definitive assessment of the prognostic significance of HPV in head and neck cancer.

A brief synopsis of the role of human papillomaviruses in cervical carcinogenesis

The expansion of our knowledge in the realms of pathology, epidemiology, and molecular biology of human papillomaviruses (HPV) has defined them as the major and best understood class of true human tumor viruses. The interaction of the papillomavirus genome with its host cell produces the majority of cytologic abnormalities at which cervical cancer screening is directed. The epidemiologic pattern of HPV infection accounts for the established association of cervical neoplasia with sexual activity. The molecular interactions of the HPV genome with its host cell suggest a plausible mechanism for its carcinogenic action. This presentation will succinctly review current knowledge of HPV biology to facilitate an understanding of the clinical significance of this virus. (Am J Obstet Gynecol 1996;175:1091-8.)

Cervical Intraepithelial Neoplasia, Cervical Cancer, and HPV

Major progress has been made to control cervical cancer in the United States and Europe using screening programs, although it remains a major cause of morbidity and mortality in the developing world. The association between cervical cancer and a sexually transmissible etiologic agent was hypothesized long before identification of human papillomaviruses (HPV) as agents that infected the genital tract. HPVs are among the most common sexually transmitted agents and have been shown to induce several squamous anogenital cancers, including squamous cell cancer of the cervix. After an etiologic role for HPV was identified in cervical cancer and CIN, efforts to understand the molecular biology of HPV were greatly expanded, enhanced by the advent of deoxyribonucleic acid (DNA) probes to identify HPV infection. Recent research has focused on specific types of HPV in relation to other recognized risk factors in the pathogenesis of CIN and invasive cervical cancer.

Cervical intraepithelial neoplasia, cervical cancer, and HPV.

Major progress has been made to control cervical cancer in the United States and Europe using screening programs, although it remains a major cause of morbidity and mortality in the developing world. The association between cervical cancer and a sexually transmissible etiologic agent was hypothesized long before identification of human papillomaviruses (HPV) as agents that infected the genital tract. HPVs are among the most common sexually transmitted agents and have been shown to induce several squamous anogenital cancers, including squamous cell cancer of the cervix. After an etiologic role for HPV was identified in cervical cancer and CIN, efforts to understand the molecular biology of HPV were greatly expanded, enhanced by the advent of deoxyribonucleic acid (DNA) probes to identify HPV infection. Recent research has focused on specific types of HPV in relation to other recognized risk factors in the pathogenesis of CIN and invasive cervical cancer.

Antiviral therapy for human papillomaviruses: rational and prospects.

To review the basic virology of human papillomavirus (HPV) and the natural history of HPV infection and to discuss current and potential therapies. The MEDLINE database (1966 to 1994) was searched to identify English-language articles and abstracts on HPV biology and antiviral chemotherapy. Peer-reviewed basic science and clinical research studies on the molecular, cellular, and human biology of HPV infection. Summaries of data from research studies on the biology of papillomavirus infection and information from review articles on the basic and applied pharmacology of antiviral agents. Papillomavirus infections are very common. Human papillomavirus infections may be asymptomatic or may be manifested in various benign or malignant lesions, most notably anogenital condyloma and anogenital carcinoma. Currently, therapeutic options for HPV infection are limited, expensive, and often ineffective. By understanding the basic virology and natural history of HPV infection, potential sites for pharmacologic intervention can be identified. Although currently available antiviral compounds are inactive against HPV, they serve as models for the rational design of HPV antiviral drugs. Although HPV infection causes substantial morbidity and expense, uniformly effective therapy for HPV infection is not currently available. Several processes in the HPV infection cycle are appropriate targets for the development of antiviral agents. The development of compounds active against HPV could prevent the benign and malignant diseases associated with HPV infection.

The Structure, Function, and Regulation of Papillomaviral Genes in Infection and Cervical Cancer

Publisher Summary This chapter summarizes developments in the understanding of the molecular biology of papillomaviral infection, with emphasis on the control of critical events in human papillomavirus (HPV) infection and cervical cancer at the level of viral gene transcription. It discusses papillomaviral replication systems and the genes involved in viral replication, and briefly reviews the interactions between viral and cellular proteins involved in neoplastic transformation. The chapter also describes cellular and viral factors involved in the control of papillomaviral gene expression, and speculates how they jointly interact to direct the expression of viral replication and transformation genes in active infection, viral latency, and cervical cancer. Progress in studies on the function of HPV genes not only has provided new insights on the role of HPV infection in cervical carcinogenesis, but also has established the molecular biology of genital HPVs as an exciting model for investigations on the molecular mechanisms of cell transformation, cell cycle control and transcriptional gene regulation.

Risk factors inducing the persistence of high-risk genital papillomaviruses in the normal cervix.

To evaluate the risk factors associated with persistence of human papillomaviruses (HPV) types 16, 18, and 33 in the normal cervix, a prospective study was carried out in Belgium of 323 women without cytological evidence of cervical intraepithelial neoplasia. Demographic and clinical data were obtained by interview, and HPV DNA was assayed in cervical-swab specimens using the Fast Multiplex Polymerase Chain Reaction-based screening and confirmatory tests. A multivariable linear regression model was constructed using four well-known risk factors: the use of an oral contraceptive which is either triphasic, or monophasic and containing ethynylestradiol in association with either norethysterone, or levonorgestrel, or lynestrenol, or gestoden, or estrogenic and containing estriol (P = 8 x 10(-5)), a positive history of genital herpes simplex virus (HSV) infection (P = 10(-4)), an age inferior or equal to 30 years (P = 0.012), and cigarette smoking (P = 0.020). Crude and adjusted relative risks were calculated for each HPV persistence predictor. The data and the results of the molecular biology of high-risk genital HPVs are consistent with the hypothesis that the use of an oral contraceptive containing simultaneously and continuously both a potent estrogen and a high activity progestative is necessary to enhance significantly HPV transcription. These observations are also consistent with the hypothesis that the oral contraceptives and HSV genital infection are responsible for HPV persistence in the normal cervix but not for HPV-induced cervical transformation.(ABSTRACT TRUNCATED AT 250 WORDS)

Human papilloma viral DNA replicates as a stable episome in cultured epidermal keratinocytes.

Human papilloma virus (HPV) is poorly understood because systems for its growth in tissue culture have not been developed. We report here that cultured human epidermal keratinocytes could be infected with HPV from plantar warts and that the viral DNA persisted and replicated as a stable episome. There were 50-200 copies of viral DNA per cell and there was no evidence to indicate integration of viral DNA into the cellular genome. There was also no evidence to suggest that viral DNA underwent productive replication. We conclude that cultured human epidermal keratinocytes may be a model for the study of certain aspects of HPV biology.