New concepts on the role of human papillomavirus in cell cycle regulation

Surveillance of human papillomavirus through salivary diagnostics - A roadmap to early detection of oropharyngeal cancer in men

Human papillomavirus (HPV) is the most common sexually transmitted disease. Certain strains have the potential to cause malignancy in multiple anatomical sites if not cleared by the immune system. In most infected people, HPV is cleared within two years. However, HPV may persist in susceptible individuals with certain risk factors, eventually leading to malignancy. New evidence suggests that over 75% of all oropharyngeal cancers (OPC) are directly attributable to HPV. It is estimated that prophylactic HPV vaccination alone may take at least 25 years to have a significant impact on reducing the incidence of OPC. The temporal link between detection of oral HPV, persistence of the infection and the subsequent development of OPC have been well established. Moreover, men have threefold higher risk than women for acquiring HPV-OPC. This comprehensive review focuses on OPC development in men, highlighting the risk factors associated with malignant transformation of HPV-OPC. Current evidence is insufficient to determine whether early identification of at-risk demographics, screening, and prompt diagnosis result in improved outcomes. Hitherto, the effectiveness of an oral HPV screening program in this regard has not been investigated. Nevertheless, the potential to emulate the success of the cervical screening program remains a very real possibility.

A costimulatory chimeric antigen receptor targeting TROP2 enhances the cytotoxicity of NK cells expressing a T cell receptor reactive to human papillomavirus type 16 E7

Immune cells modified to express a tumor-reactive T cell receptor (TCR) have shown limited efficacy as stand-alone therapy against solid tumors. Genital and oropharyngeal carcinomas induced by human papillomavirus (HPV) type 16 express constitutively its E6 and E7 oncoproteins, which makes them convenient targets for adoptive cell immunotherapy. However, viral antigen presentation by tumor cells is low and limits the anti-tumor efficacy of CD8+ T cells. To enhance the functionality of immune effector cells, we have devised a strategy combining a costimulatory chimeric antigen receptor (CAR) with a TCR. We used a clinically tested TCR specific to E7 (E7-TCR) of HPV16 and a newly constructed CAR targeting the trophoblast cell surface antigen 2 (TROP2), which carried the intracellular costimulatory domains CD28 and 4-1BB, but was devoid of the CD3ζ domain. Flow cytometry analyses showed a notable upregulation of activation markers and of cytolytic molecule release by NK-92 cells genetically engineered to express CD3, CD8 and both E7-TCR and TROP2-CAR, after co-incubation with HPV16+ cervical cancer cells. Furthermore, the E7-TCR/TROP2-CAR NK-92 cells demonstrated enhanced antigen-specific activation and augmented cytotoxicity against tumor cells compared with NK-92 cells expressing the E7-TCR alone. A costimulatory TROP2-CAR can synergistically cooperate with the E7-TCR in NK cells thereby enhancing their signaling strength and antigen-specific cytotoxicity. This approach might improve the outcome of adoptive cell immunotherapies for HPV16+ cancer patients that are currently under investigation.

Human papillomavirus vaccination and cervical cancer risk

Persistent human papillomavirus infection is the central cause of cervical cancer, the leading cause of cancer death among women worldwide. Clear evidence from both randomized trials and population based studies shows that vaccination against human papillomavirus reduces the incidence of cervical pre-cancer. These data suggest that the vaccine reduces the incidence of cervical cancer. However, human papillomavirus vaccine coverage is inadequate in all countries, especially in low and middle income countries where disease burden is highest. Supply side strategies to improve coverage include increasing the availability of low cost vaccines, school located delivery, single dose vaccine schedules, and development of vaccines that do not need refrigeration. Demand side strategies include enhancing provider recommendations, correcting misinformation, and public awareness campaigns. The near elimination of cervical cancer is achievable through increased uptake of human papillomavirus vaccination and efforts to increase screening for cervical cancer, especially when enacted to reduce disparities in across the world.

The ‘Why and How’ of Cervical Cancers and Genital HPV Infection

Knowing about the virology of human papillomavirus (HPV) including its structure, functions and mechanism of infection, helps in understanding the disease process and morphology of precancerous lesions for cervical cancer. Two types of HPV, low- and high-risk type, adopt different mechanisms of infection which cannot be differentiated on morphological basis. In addition to HPV infection, many other factors such as genetic predisposition, hormonal factors, host immune response, and multiple sexual partners can modify the course and progression of the disease. The viral genome comprises early and late proteins. These early and late genes are expressed in particular course of time after initial infection. Various products of early genes (E1–E7) coordinate for completion of viral life cycle in maturing squamous epithelium by utilizing replication factors and DNA polymerase enzyme of the host cell nucleus. The late genes are mainly concerned with packaging of the viral particles and their release through mature squamous cells. The episomal form of infection seen in the low-risk group of viruses results in productive infection whereas the integrated form seen in high-risk group of viruses is the basis of disruption of host cell growth cycle by inactivating two important tumor suppressor genes p53 and Rb gene by products of E6 and E7 genes. Cervical precancerous lesions and cancer are the resultant effect of the accumulation of mutations. This article discusses the virology of HPV, pathogenesis of HPV infection, and various other factors modifying the disease course.

Cellular Functions of HPV16 E5 Oncoprotein during Oncogenic Transformation

The human papillomavirus (HPV) is recognized as the main etiologic agent associated with cervical cancer. HPVs are epitheliotropic, and the ones that infect the mucous membranes are classified into low-risk (LR) and high-risk (HR) types. LR-HPVs produce benign lesions, whereas HR-HPVs produce lesions that may progress to cancer. HR-HPV types 16 and 18 are the most frequently found in cervical cancer worldwide. E6 and E7 are the major HPV oncogenic proteins, and they have been profusely studied. Moreover, it has been shown that the HPV16 E5 (16E5) oncoprotein generates transformation, although the molecular mechanisms through which it carries out its activity have not been well defined. In contrast to E6 and E7, the E5 open reading frame is lost during the integration of the episomal HPV DNA into the cellular genome. This suggests that E5 acts at the early stages of the transformation process. In this review, we focused on the biochemical characteristics and functions of the HPV E5 oncoprotein, mainly on its association with growth factor receptors and other cellular proteins. Knowledge of the HPV E5 biology is important to understand the role of this oncoprotein in maintaining the viral cycle through the modulation of proliferation, differentiation, and apoptosis, as well as the alteration of other processes, such as survival, adhesion, migration, and invasion during early carcinogenesis. Finally, we summarized recent research that uses the E5 oncoprotein as a therapeutic target, promising a novel approach to the treatment of cervical cancer in its early stages.

Immunology of HPV-mediated cervical cancer: current understanding

Human papilloma virus (HPV) has emerged as a primary cause of cervical cancer worldwide. HPV is a relatively small (55 nm in diameter) and non-enveloped virus containing approximately 8 kb long double stranded circular DNA genome. To date, 228 genotypes of HPV have been identified. Although all HPV infections do not lead to the development of malignancy of cervix, only persistent infection of high-risk types of HPV (mainly with HPV16 and HPV18) results in the disease. In addition, the immunity of the patients also acts as a key determinant in the carcinogenesis. Since, no HPV type specific medication is available for the patient suffering with cervical cancer, hence, a deep understanding of the disease etiology may be vital for developing an effective strategy for its prevention and management. From the immunological perspectives, the entire mechanisms of disease progression still remain unclear despite continuous efforts. In the present review, the recent developments in immunology of HPV-mediated cervix carcinoma were discussed. At the end, the prevention of disease using HPV type specific recombinant vaccines was also highlighted.

Cyclin-dependent kinases and CDK inhibitors in virus-associated cancers

The role of several risk factors, such as pollution, consumption of alcohol, age, sex and obesity in cancer progression is undeniable. Human malignancies are mainly characterized by deregulation of cyclin-dependent kinases (CDK) and cyclin inhibitor kinases (CIK) activities. Viruses express some onco-proteins which could interfere with CDK and CIKs function, and induce some signals to replicate their genome into host's cells. By reviewing some studies about the function of CDK and CIKs in cells infected with oncoviruses, such as HPV, HTLV, HERV, EBV, KSHV, HBV and HCV, we reviewed the mechanisms of different onco-proteins which could deregulate the cell cycle proteins.

Transcriptional Regulation of Epithelial to Mesenchymal Transition Related Genes by Lipopolysaccharide in Human Cervical Cancer Cell Line HeLa

Objective:

Cancer is one of the common diseases in the world, and cervical cancer is the fourth one. In this type of cancer, many risk factors, especially infectious diseases, such as human papilloma virus (HPV) and gram-negative bacteria can have important effects on the expression of epithelial to mesenchymal transition related genes like Snail,E-cadherin, and ZEB-1, responsible for connecting cell tissues. In this study, we have investigated the effect of Escherichia coli O111:B4 Lipopolysaccharide (LPS) on HPV positive cell line (HeLa), the expression level of the (Snail, E-cadherin, and ZEB-1), HPV oncogenes (E6, E7) and also microRNA-9, 192.

Materials and Methods:

HeLa cell line was treated with LPS to analyze Snail, E-cadherin, ZEB-1, E6, E7 and also microRNA-9, 192 expression by quantitative real-time PCR in 24, 48 and 72 hours.

Results:

Quantitative real-time PCR revealed a significant reduction in E-cadherin mRNA level at 10ug/L of LPS in three time-points and after 24 hours at 5ug/L of LPS; however, ZEB-1 at 10ug/L of LPS and Snail at 5, 10ug/L of LPS are up-regulated. E7 also illustrated a slight increase, but we did not find any relationship between E7 and LPS treatment. Additionally, there are upward trends in microRNA-9, 192 levels.

Conclusion:

The result of this study, LPS is able to reduce E-cadherin expression, caused by increase in repressor E-cadherin protein expression and some microRNAs, probably. Since bacterial infection can be in cervical site, it is likely to be effective in reducing the E-cadherin expression in the EMT and enhance cancer process, therefore; removing these infections by using the appropriate antibiotics may result in slowing down this process, which requires more research.

Delineation of the HPV11E6 and HPV18E6 Pathways in Initiating Cellular Transformation

Although high-risk human papillomaviruses (HPVs) are the major risk factors for cervical cancer they have been associated with several other cancers, such as head and neck and oral cancers. Since integration of low-risk HPV11 DNA has been demonstrated in esophageal tumor genomes, this study compared the effects of low-risk HPV11E6 and high-risk HPV18E6 on cellular gene expression. The HPV11E6 and HPV18E6 genes were cloned into an adenoviral vector and expressed in human keratinocytes (HaCaT) in order to investigate early events and to eliminate possible artifacts introduced by selective survival of fast growing cells in stable transfection experiments. HPV11E6 had very little effect on p21 and p53 gene expression, while HPV18E6 resulted in a marked reduction in both these proteins. Both HPV11E6 and HPV18E6 enabled growth of colonies in soft agar, but the level of colony formation was higher in HPV18E6 infected cells. DNA microarray analysis identified significantly differentially regulated genes involved in the cellular transformation signaling pathways. These findings suggest that HPV11E6 and HPV18E6 are important in initiating cellular transformation via deregulation of signaling pathways such as PI3K/AKT and pathways that are directly involved in DNA damage repair, cell survival, and cell proliferation. This study shows that the low-risk HPV11E6 may have similar effects as the high-risk HPV18E6 during the initial stages of infection, but at a much reduced level.

Cervical cancer in sub-Saharan Africa: a preventable noncommunicable disease

INTRODUCTION

Infections caused by high-risk human papillomavirus (HPV) are responsible for 7.7% of cancers in developing countries, mainly cervical cancer. This disease is steadily increasing in sub-Saharan Africa, with more than 75,000 new cases and 50,000 deaths yearly, further increased by HIV infection. Areas covered: The current status of cervical cancer associated with HPV in sub-Saharan Africa has been systematically revised. The main issues discussed here are related to the public health burden of cervical cancer in sub-Saharan Africa and predictions for the coming decades, including molecular epidemiology and determinants of HPV infection in Africa, and promising prevention measures currently being evaluated in Africa. Expert commentary: By the year 2030, cervical cancer will kill more than 443,000 women yearly worldwide, most of them in sub-Saharan Africa. The increase in the incidence of cervical cancer in Africa could counteract the progress made by African women in reducing maternal mortality and longevity. Nevertheless, cervical cancer is a potentially preventable noncommunicable disease, and intervention strategies to eliminate cervical cancer as a public health concern should be urgently implemented.

Evaluation of the Prevalence Rate and the Prognostic Effect of Human Papilloma Virus Infection in a Group of Patients With Oral Cavity Squamous Cell Carcinoma

BACKGROUND

Squamous cell carcinoma (SCC) is the most common malignancy of the oral cavity. A relationship between the human papilloma virus (HPV) infection and the prognosis of oral cavity SCC (OCSCC) has been discussed before.

OBJECTIVES

We investigated the prevalence rate of HPV status in patients with OCSCC, and its effects on clinicopathological characteristics of tumors and patients' prognosis.

PATIENTS AND METHODS

Sections of formalin-fixed, paraffin-embedded tissue blocks from 114 histopathologically confirmed OCSCC cases were investigated in this study. Polymerase chain reaction (PCR) was applied to evaluate the HPV status in the samples.

RESULTS

Fifteen (13.16%) cases were identified as HPV positive. The detected viral subtypes in this study were the subtypes 6 and 11. The stage and especially lymph node stage was significantly higher in the HPV positive group compared to the HPV negative group (P = 0.04). Disease free survival (DFS) was remarkably lower in the HPV positive group compared to the HPV negative group (13.9 vs. 49.9 months, P = 0.02). Overall survival (OS) was also significantly inferior in the HPV positive group (15.7 vs. 49.6 months, P = 0.01). In the current study, no significant differences were observed between two groups in relation to the variables of age, gender, tumors site, tumor size, tumor grading and also the recurrence rate.

CONCLUSIONS

The observed higher mortality rate among the HPV positive group indicates the poorer prognosis of this group in comparison with the HPV negative patients. The incidence rate of HPV infection was low in the studied samples; however, interaction of subtypes 6 and 11 of HPV in poorer prognosis of the patients and a carcinogenic role of HPV in OCSCC cannot be ruled out.

Human Papillomavirus: Current and Future RNAi Therapeutic Strategies for Cervical Cancer

Human papillomaviruses (HPVs) are small DNA viruses; some oncogenic ones can cause different types of cancer, in particular cervical cancer. HPV-associated carcinogenesis provides a classical model system for RNA interference (RNAi) based cancer therapies, because the viral oncogenes E6 and E7 that cause cervical cancer are expressed only in cancerous cells. Previous studies on the development of therapeutic RNAi facilitated the advancement of therapeutic siRNAs and demonstrated its versatility by siRNA-mediated depletion of single or multiple cellular/viral targets. Sequence-specific gene silencing using RNAi shows promise as a novel therapeutic approach for the treatment of a variety of diseases that currently lack effective treatments. However, siRNA-based targeting requires further validation of its efficacy in vitro and in vivo, for its potential off-target effects, and of the design of conventional therapies to be used in combination with siRNAs and their drug delivery vehicles. In this review we discuss what is currently known about HPV-associated carcinogenesis and the potential for combining siRNA with other treatment strategies for the development of future therapies. Finally, we present our assessment of the most promising path to the development of RNAi therapeutic strategies for clinical settings.

Human papillomavirus-related head and neck squamous cell carcinoma variants

During the last few decades, a phenotypically distinct type of head and neck squamous cell carcinoma (SCC), which is etiologically related to human papillomavirus (HPV), has emerged, and its prevalence continues to increase. The tumors are site-specific with special predilection for the oropharynx. They are morphologically and molecularly distinct and are responsive to different types of treatment modalities, with excellent clinical outcome, in spite of early lymph node metastasis. Microscopically, the carcinomas are nonkeratinizing SCCs. More recently, other variants that are believed to be etiologically related to HPV are reported. As a result, several clinical and pathologic questions have emerged. Importantly, whether the virus is biologically active in these tumors and involved in their pathogenesis, and second, what are the clinical implications with regard to patient management and outcome in these HPV-related variants. This review is an attempt to answer some of these questions based on information derived from available yet limited number of publications. The variants to be discussed include nonkeratinizing SCC (NKSCC), NKSCC with maturation (hybrid type), keratinizing SCC (KSSC), basaloid squamous carcinoma (BSCC), undifferentiated carcinoma (UC), papillary SCC (PSCC), small cell carcinoma, adenosquamous carcinoma (AdSCC), and spindle cell (sarcomatoid) carcinoma.

Tertiary prevention of cervical cancer

Human pappilomavirus (HPV) has been recognized as the most common sexually transmitted disease in the world and over 100 different HPV types have been identified. Persistent HPV infection has been closely linked to the development of invasive cervical cancer. Although surgical and ablative therapies have been the mainstay of treatment, vaccination against the main oncogenic type of HPV is a reasonable preventive strategy for HPV-induced cervical cancer.

HIV-1 Tat induces DNMT over-expression through microRNA dysregulation in HIV-related non Hodgkin lymphomas

BACKGROUND

A close association between HIV infection and the development of cancer exists. Although the advent of highly active antiretroviral therapy has changed the epidemiology of AIDS-associated malignancies, a better understanding on how HIV can induce malignant transformation will help the development of novel therapeutic agents.

METHODS

HIV has been reported to induce the expression of DNMT1 in vitro, but still no information is available about the mechanisms regulating DNMT expression in HIV-related B-cell lymphomas. In this paper, we investigated the expression of DNMT family members (DNMT1, DNMT3a/b) in primary cases of aggressive B-cell lymphomas of HIV-positive subjects.

RESULTS

Our results confirmed the activation of DNMT1 by HIV in vivo, and reported for the first time a marked up-regulation of DNMT3a and DNMT3b in HIV-positive aggressive B-cell lymphomas. DNMT up-regulation in HIV-positive tumors correlated with down-regulation of specific microRNAs, as the miR29 family, the miR148-152 cluster, known to regulate their expression. Literature reports the activation of DNMTs by the human polyomavirus BKV large T-antigen and adenovirus E1a, through the pRb/E2F pathway. We have previously demonstrated that the HIV Tat protein is able to bind to the pocket proteins and to inactivate their oncosuppressive properties, resulting in uncontrolled cell proliferation. Therefore, we focused on the role of Tat, due to its capability to be released from infected cells and to dysregulate uninfected ones, using an in vitro model in which Tat was ectopically expressed in B-cells.

CONCLUSIONS

Our findings demonstrated that the ectopic expression of Tat was per se sufficient to determine DNMT up-regulation, based on microRNA down-regulation, and that this results in aberrant hypermethylation of target genes and microRNAs. These results point at a direct role for Tat in participating in uninfected B-cell lymphomagenesis, through dysregulation of the epigenetical control of gene expression.

Histopathologic risk factors in oral and oropharyngeal squamous cell carcinoma variants: an update with special reference to HPV-related carcinomas

Accurate identification of the microscopic risk factors of oral and oropharyngeal (OP) squamous cell carcinomas (SCC) and their morphologic variants is of at most importance, as these generally determine treatment modalities, prognosis and overall patient outcome. The great majority of oral and oropharyngeal squamous cell carcinomas are microscopically described as kerartinizing squamous cell carcinoma (KSCC). They bear certain resemblance to keratinizing stratified squamous epithelium. Tobacco habits and excessive consumption of alcoholic beverages have been considered to be the main etiologic agents in these carcinomas. The tumors occurred in older patients more commonly affected the oral tongue and floor of the mouth with well established morphologic risk factors including tumor grade, pattern of invasion and perineural involvement. Within the last 30 years however, the advent and expanding prevalence of high risk human papillomavirus (HPV) as an important etiologic agent for head and neck squamous cell carcinoma, particularly in the OP, has resulted in a significant change in the established morphologic criteria for risk assessment. The majority of HPV relate carcinomas of the OP are nonkeratinizing squamous cell carcinoma (NKSCC). These tumors are found to be more responsive to treatment with a favorable patient outcome and good prognosis. Consequently, alterations in treatment protocols aimed at de-escalation are currently being evaluated. More recently, other morphologic variants that are HPV positive are reported with increasing frequency in the OP and other head and neck sites. As a result, several clinical and pathologic questions have emerged. Importantly, whether the virus is biologically active in these tumors and involved in their pathogenesis, and second, what are the clinical implications with regard to patient management and outcome in the HPV-related variants. Examples of HPV-related squamous cell carcinoma variants that will be addressed here are: basaloid squamous cell carcinoma (BSCC), undifferentiated carcinoma (UCa), papillary squamous carcinoma (PSCC) and small cell carcinoma. Some studies have suggested favorable prognosis in some variants, analogous to that of the (NKSCC), while others showed poorer outcome. So far the number of studies on this subject is limited and the number of cases evaluated in each investigation is few. Because of that, it is prudent at this stage, not to alter management protocols as a result of identification of HPV in these variants and to await additional information

Key words:Histopathologic risk-factors, oral cavity, oropharynx, squamous cell carcinoma variants, keratinizing squamous cell carcinoma, nonkeratinizing squamous cell carcinoma, HPV, basaloid squamous cell carcinoma, undifferentiated carcinoma, papillary squamous cell carcinoma, small cell carcinoma.

Infecção pelo papilomavírus humano: etiopatogenia, biologia molecular e manifestações clínicas

O papilomavírus humano (HPV) é um vírus DNA que apresenta tropismo por células epiteliais, causando infecções na pele e nas mucosas. A replicação do HPV ocorre no núcleo das células escamosas e o seu ciclo de vida é diretamente relacionado ao programa de diferenciação da célula hospedeira. Até o momento, foram completamente caracterizados cerca de 100 tipos diferentes de HPVs e há um grande número adicional de tipos ainda não sequenciados. Além de ser o responsável por lesões benignas de pele e mucosas, o HPV também está envolvido no desenvolvimento de diversos tumores cutaneomucosos: doença de Bowen, cânceres de pele não melanoma e carcinomas genitais. Esta revisão aborda as características do HPV, quadros cutâneos e mucosos benignos e malignos causados por ele e os principais métodos empregados em sua detecção e tipagem.

Clinicopathologic Implications of the Epidermal Growth Factor Receptor, Cyclooxygenase 2 Expression, and Human Papillomavirus Status in Squamous Cell Carcinoma of the Uterine Cervix in the Elderly

Objectives:

To find information on invasive squamous cervical carcinoma in the elderly, 110 invasive squamous cervical carcinomas obtained from 2 groups of patients (aged <60 and >60 years) were analyzed for human papillomavirus (HPV) status by polymerase chain reaction study, for immunohistochemical epidermal growth factor receptor (EGFR), cyclooxygenase 2 (Cox-2) expression, and clinicopathologic features.

Methods:

The HPV status and the expression of Cox-2 and EGFR in the younger and older women were compared and correlated with the grading, staging neoplasm, and lymph nodal status, using Fisher test and Spearman nonparametric correlation test. Overall survival curves were drawn using Kaplan-Meier estimates and were compared using log-rank tests in the whole series of 110 patients. Multinomial logistic regression was also used.

Results and Conclusions:

The number of neoplasms with higher staging was significantly greater than those in the younger women (P= 0.04). The mortality was higher in the older group than in the younger patients (P= 0.006).

In the elderly, the presence of HPV DNA in 65% of cases, and in the absence of sexual activity, could be due to reactivation of latent HPV infection, which might be due to an impairment of host immunologic response.

The overexpression of Cox-2 in a number of cases was significantly higher in the older group than in the younger group (P= 0.032, Fisher exact test), but this immunoreactivity is not related to the staging, grading, EGFR expression, or to the presence of HPV.

The simultaneous expression of Cox-2 and EGFR had a poor prognostic significance, showing lower survival rates than cases without this immunoreactivity (P= 0.002), on univariate analysis.

On multivariate analysis, Cox-2 and EGFR immunopositivity did not reveal any correlation between these markers and prognosis probably because the number of cases considered was not particularly high.

E6 and E7 fusion immunoglobulin from human papilloma virus 16 induces dendritic cell maturation and antigen specific activation of T helper 1 response

Human papilloma virus (HPV) 16 causes cervical cancer. Induction of oncogenesis by HPV 16 is primarily dependent on the function of E6 and E7 proteins, which inactivate the function of p53 and pRB, respectively. Thus, blocking the activity of the E6 and E7 proteins from HPV 16 is critical to inhibiting oncogenesis during infection. We have expressed and purified soluble HPV 16 E6 and E7 fusion immunoglobulin (Ig), which were combined with the constant region of an Ig heavy chain, in a mammalian system. To assess whether soluble E6 and E7 fusion Igs induce effective cellular immune responses, immature dendritic cells (DCs) were treated with these fusion proteins. Soluble E6 and E7 fusion Igs effectively induced maturation of DCs. Furthermore, immunization with soluble E6 and E7 fusion Igs in mice resulted in antigen-specific activation of T helper 1 (Th1) cells. This is the first comprehensive study to show the molecular basis of how soluble HPV 16 E6 or E7 fusion Igs induces Th1 responses through the maturation of DCs. In addition, we show that DC therapy using soluble HPV E6 and E7 fusion Igs may be a valuable tool for controlling the progress of cervical cancer.

Differential expression of cellular microRNAs in HPV-11 transfected cells. An analysis by three different array platforms and qRT-PCR

Human papillomavirus type 11 (HPV-11) infects the genital and the respiratory tract leading to condylomas and respiratory papillomatosis. HPV infections are restricted to epithelial tissue and the progression through the virus lifecycle is tightly coordinated to the differentiation of the host cell. The changes of cellular microRNAs by HPV-11 gene expression were investigated in a cell culture model of HaCaT cells transfected with HPV-11, with the goal of understanding which cellular processes were affected by the virus. Human microRNA profiling was conducted on three different array platform systems and because very few microRNAs (miR-663, -638, -149* and -92b*) were consistently found in all three array data sets we performed extensive statistical analyses of the array data and the qRT-PCR validation. We assume that the most reliable differentially expressed microRNAs are the ones identified by more than one array platform. We also show that TaqMan® qRT-PCR validation is of limited use for less abundant microRNAs.

Up-regulation of lipocalin 2 is associated with high-risk human papillomavirus and grade of cervical lesion at baseline but does not predict outcomes of infections or incident cervical intraepithelial neoplasia

Our objective was to assess whether neutrophil gelatinase-associated lipocalin (NGAL)/lipocalin 2 (LCN2) expression in cervical human papillomavirus (HPV) lesions has implications on the outcome of HPV infections or disease progression. Cervical biopsy specimens from 225 women in the Latin American Screening study were analyzed for NGAL/LCN2 expression using immunohistochemical analysis, to assess associations with cervical intraepithelial neoplasia (CIN) grade, high-risk HPV, and in predicting outcomes of high-risk (HR)-HPV infections. Expression of NGAL/LCN2 increased with lesion grade (odds ratio [OR], 3.86; 95% confidence interval [CI], 1.53-9.71; P = .001). Up-regulation was also related to HR-HPV detection (OR, 2.21; 95% CI, 1.15-4.24; P = .016) and showed a linear relationship to HR-HPV load (P = .002). NGAL/LCN2 expression was of no value in predicting the outcomes of HR-HPV infections or the surrogate end points (incident CIN 1+ and CIN 2+) of progressive disease. Because the SV40 large T antigen is a powerful up-regulator of this lipocalin, up-regulation of NGAL/LCN2 in CIN is probably induced by HR-HPV E6 oncoprotein, most likely by eliminating its normal transcription repression exerted by wild-type p53.

Up-regulation of 14-3-3sigma (Stratifin) is associated with high-grade CIN and high-risk human papillomavirus (HPV) at baseline but does not predict outcomes of HR-HPV infections or incident CIN in the LAMS study

To assess whether the potentially high-risk (HR) human papillomavirus (HPV)-related up-regulation of 14-3-3sigma (stratifin) has implications in the outcome of HPV infections or cervical intraepithelial neoplasia (CIN) lesions, cervical biopsy specimens from 225 women in the Latin American Screening Study were analyzed for 14-3-3sigma expression using immunohistochemical analysis. We assessed its associations with CIN grade and HR HPV at baseline and value in predicting outcomes of HR-HPV infections and the development of incident CIN 1+ and CIN 2+. Expression of 14-3-3sigma increased in parallel with the lesion grade. Up-regulation was also significantly related to HR-HPV detection (P = .004; odds ratio, 2.71; 95% confidence interval, 1.37-5.35) and showed a linear relationship to HR-HPV loads (P = .003). 14-3-3sigma expression was of no value in predicting the outcomes (incident, persistent, clearance) of HR-HPV infections or incident CIN 1+ and CIN 2+. 14-3-3sigma is not inactivated in cervical carcinoma and CIN but is up-regulated on transition from CIN 2 to CIN 3. Its normal functions in controlling G(1)/S and G(2)/M checkpoints are being bypassed by HR HPV.

Expression of papillomavirus L1 proteins regulated by authentic gene codon usage is favoured in G2/M-like cells in differentiating keratinocytes

We investigated whether differentiation-dependent expression of papillomavirus (PV) L1 genes is influenced by the cell cycle state in keratinocytes (KCs) grown in vitro or in vivo. In primary keratinocytes, flow cytometry revealed a clear shift from predominantly G0/G1 to G2/M cells from day 1 to day 7, with a three-fold increase in G2/M-like cells in day 7 keratinocytes that showed approximately 50% of the cells expressed a terminal differentiation marker involucrin. The correlation between the levels of the L1 proteins expressed from authentic (Nat) L1 genes of HPV6b and BPV1 and the frequencies of the G2/M-like KCs was significantly positive, while in contrast, a significantly negative correlation in the levels of L1 proteins expressed from codon-modified (Mod) L1 genes of HPV6b and BPV1 with the frequencies of the G2/M-like KCs was observed. Experiments using cell cycle arrest reagents (all-trans retinoic acid (RA) and colchicine) confirmed that L1 proteins expressed from PV Nat L1 genes were facilitated in G2/M-like KCs upon differentiation. Using immunofluorescence microscopy, it appears that L1 proteins from PV Nat L1 genes were co-expressed with cyclin B1, while the L1 proteins expressed from PV Mod L1 genes were preferentially associated with cyclin D2 in KCs in vitro and in mouse skin. Our results demonstrate that (1) expression of the L1 proteins from Nat L1 genes of HPV6b and BPV1 that have strong codon usage bias with A or T at codon third position dependent on KC differentiation is favoured by the G2/M-like environment and (2) codon modifications can alter the cell differentiation-dependent and cell cycle-associated patterns of expression of the PV L1 proteins in KCs.

Up-regulation of plasminogen activator inhibitor-2 is associated with high-risk HPV and grade of cervical lesion at baseline but does not predict outcomes of high-risk HPV infections or incident CIN

Protease inhibitor serpin-B2 (plasminogen activator inhibitor-2 [PAI-2]) protects pRb from degradation in human papillomavirus (HPV)-18+ HeLa cells. Our objective was to assess whether the pRb-mediated HPV-suppressive effect of PAI-2 in cancer cell lines has implications in the outcome of HPV infections. Cervical biopsy specimens from 225 women were analyzed for PAI-2 expression to assess its value as a predictor of cervical intraepithelial neoplasia (CIN) grade, high-risk (HR) HPV at baseline, outcomes of HR-HPV infections, and the development of incident CIN. PAI-2 expression increased in parallel with lesion grade. Nuclear PAI-2 expression was significantly related to HR-HPV detection and had a linear relationship with HR-HPV load. PAI-2 expression was of no value in predicting the outcomes of HR-HPV infections. The same was true for PAI-2 as a predictor of surrogate end points (incident CIN 1+, CIN 2+) of progressive disease. PAI-2 expression is up-regulated on transition from CIN 2 to CIN 3. The HR-HPV suppressive effects of PAI-2 were not related to more favorable outcomes of HR-HPV infections or lower risk of disease progression to CIN.

Immunosuppressive cytokine Interleukin-10 (IL-10) is up-regulated in high-grade CIN but not associated with high-risk human papillomavirus (HPV) at baseline, outcomes of HR-HPV infections or incident CIN in the LAMS cohort

Bypassing the local immunological defense reactions in the cervix is one of the prerequisites for human papillomaviruses (HPV) infections to progress to intraepithelial neoplasia (CIN). The role of potent immunosuppressive cytokines, e.g., interleukin-10 (IL-10), depressing these local virus-specific immunological responses is incompletely studied. To assess, whether IL-10 expression in cervical HPV lesions has any implications in the outcome of HPV infections or disease progression to CIN. Baseline cervical biopsies from 225 women of the LAMS study sub-cohort were analyzed for IL-10 expression using immunohistochemistry, to assess its associations with CIN grade, and high-risk HPV (HR-HPV) at baseline, as well as in predicting outcomes of HR-HPV infections, and development of incident CIN1+ and CIN2+ in this longitudinal setting. Expression of IL-10 in cervical lesions was up-regulated most often in high-grade CIN, and IL-10 over-expression retained its value as independent predictor of CIN2+ (odds ratio (OR) = 4.92) and CIN3+ (OR = 7.51) also in multivariate model, including HR-HPV and several known covariates of IL-10 expression. Up-regulation was not related to HR-HPV detection, and showed no relationship to HR-HPV viral loads. Using longitudinal predictive indicators (SE, SP, PPV, NPV), IL-10 expression was of no value in predicting (1) the outcomes of HR-HPV infections, or (2) the surrogate endpoints (incident CIN1+, CIN2+) of progressive disease. IL-10 over-expression (along with HR-HPV) was one of the independent covariates of CIN2/3. This immunosuppressive cytokine might play an important role in creating a microenvironment that favors progressive cervical disease and immune evasion by HR-HPV.

Human papillomavirus typing and viral gene expression analysis for the triage of women with abnormal results from papanicolaou test smears to colposcopy

CONTEXT

A cascade of molecular tests for human papillomavirus (HPV), as a follow-up to Papanicolaou test screening, could eliminate unnecessary colposcopy. Tests based on detection of HPV E6 messenger RNA (mRNA) are already being used as screening tools, but there is a good biological rationale for expecting that an increase in the relative amounts of HPV E6 mRNA in cervical samples may better predict cancerous transformation.

OBJECTIVE

To compare some of the available diagnostic methods and our novel method of relative quantification (RQ) of HPV gene expression for the effective triage of women with abnormal results from Papanicolaou tests to colposcopy.

DESIGN

Sensitivities, specificities, and likelihood ratios were calculated for repeat Papanicolaou test smears, HPV DNA polymerase chain reactions, HPV genotyping, HPV-16 E6 mRNA detection, and the RQ of HPV-16 E6 mRNA calibrated to cellular RNA and DNA levels and standardized to viral load.

RESULTS

Human papillomavirus genotype in combination with a repeat Papanicolaou test can be used to categorize most women (96%) with cervical intraepithelial neoplasia of grade 2 or higher for colposcopy while eliminating 44% of women with cervical intraepithelial neoplasia 1 or less. The presence of HPV-16 E6 mRNA (P < .001) and RQ of HPV-16 E6 mRNA (P < .001) displayed significant median differences among the various grades of cervical intraepithelial neoplasia. Further testing of women who are positive for HPV-16 demonstrated that the RQ of E6 mRNA has diagnostic potential when combined with Papanicolaou testing in populations with higher disease prevalence.

CONCLUSIONS

The RQ of HPV E6 mRNA and HPV genotype could be useful in a cascade of diagnostic testing designed to refer women with findings of cervical abnormalities for colposcopy or treatment while reducing triage numbers.

Microarray analysis identifies differentially expressed genes induced by human papillomavirus type 18 E6 silencing RNA

The oncoprotein E6 of high-risk human papillomavirus (HPV) types promotes cell proliferation and contributes to carcinogenesis of HPV-positive cervical cancer cells. In this study, we used small interfering RNA (siRNA) technology to silence the E6 gene in HPV-18-transformed human cervical cell line HeLa and determined the effects of E6 gene knockdown on the cell by using microarray-based gene expression profiling coupled with gene functional classification with bioinformatics methods. Silencing RNA prepared by siRNA expression cassettes against HPV-18 E6 gene could significantly inhibit E6 gene expression and induce HeLa cells to apoptosis. The microarray analysis identified 359 differentially expressed genes containing 307 up-regulated and 52 down-regulated genes. We analyzed the gene functions and cellular pathways in detail, including cell cycle-related genes, CCNG1 and p21; apoptosis-related genes, CASP4, CASP6, IGFBP3, and DFFA; ubiquitin proteolysis pathway-related genes, UBE3A and UBE2C; keratinocyte differentiation-related genes, KRT4, KRT6E, and KRT18; and antioncogenes, RECK and VEL. In addition, it can be concluded that cellular apoptosis induced by HPV-18 E6 siRNA mainly depends on the P53 and ubiquitin proteolysis pathway to regulate gene expression, consequently inhibiting cell proliferation and promoting cell apoptosis. Meanwhile, activation of antioncogene and upper regulation of immunization-related genes signified the degression of the malignant extent of tumor cells after E6 inhibition. Our approach, which combines the use of siRNA-mediated gene silencing, microarray screening, and functional classification of differential genes, can be used in functional genomics study to elucidate the role of E6 oncogene in the carcinogenesis of HPV-18 and provide some possible targets for clinical treatment and drug development of cervical cancer.

Immunotherapeutic polyoma and human papilloma virus-like particles

Polyomavirus and human papillomavirus (HPV) virus-like particles (VLPs) can be obtained by producing their major capsid protein VP1 (for polyomavirus) or L1 (for HPV) free from other viral genes in, for example, a baculovirus insect system, yeast, Escherichia coli or similar systems. Polyomavirus and HPV VLPs can immunize healthy individuals, and in some cases T-cell-deficient hosts, against primary infection with the corresponding virus. Chimeric VLPs from polyomaviruses or HPVs containing fusion proteins between the VP1/L1 or VP2/VP3/L2 minor capsid proteins and selected antigens can also be produced. These VLPs can then induce B- or T-cell immune responses and be used as preventive or therapeutic vaccines against cancers induced by the corresponding virus, or a cancer bearing the selected tumor antigen.

The future of vaccines for cervical cancer

Cervical cancer continues to cause significant morbidity and mortality worldwide, making prophylactic cervical cancer vaccines an important focus for cervical cancer prevention. The increasing accessibility of these vaccines worldwide has the potential to greatly decrease the incidence and burden of disease in the future. However, current prophylactic vaccines offer no therapeutic benefit for persons already infected with human papillomavirus HPV types targeted by vaccines or persons with precancerous lesions or cervical cancer. The protection offered by current vaccines is primarily against HPV types used to derive the vaccine, although partial cross-protection for related virus types has been observed. Herein, we describe findings from preclinical and clinical studies that employ vaccine strategies that have the potential to shape the future of vaccines against cervical cancer. Modalities include prophylactic strategies to target more oncogenic virus types by using the minor capsid antigen L2 and/or by increasing the number of types used to derive virus-like particle vaccines. Therapeutic strategies include the development of vaccines against HPV early proteins (targets for cellular immunity) for the resolution of precancerous lesions and cervical cancer. Future applications of existing virus-like particle-based vaccines are also discussed.

The impact of the distribution of human papillomavirus types and associated high-risk lesions in a colposcopy population for monitoring vaccine efficacy

CONTEXT

Impact studies of the new human papillomavirus (HPV) vaccines will be biased unless local baseline distribution studies are conducted. Vaccine cross protection for other important oncogenic HPV types and the emergence of potential genotype replacements require the knowledge of the prevaccine epidemiology of HPV.

OBJECTIVE

To determine the prevaccine distribution of HPV types in Saskatchewan, using a subpopulation of women referred to a colposcopy clinic.

DESIGN

One thousand three hundred fifty-five specimens obtained during colposcopic examination were typed for HPV using L1 or E1 gene polymerase chain reaction and direct sequencing. HPV-16 and HPV-31 infections were confirmed with real-time E6 polymerase chain reaction. Indeterminate samples were analyzed using Luminex technology. Correlations of the HPV type and histology were examined for statistical significance.

RESULTS

The most commonly identified genotype in patients with cervical intraepithelial neoplasia grade 2 or worse was HPV-16 (46.7%) followed by HPV-31 (14.7%) and then HPV-18 (3.9%). Fifteen of 330 specimens that were positive for HPV-16 or HPV-31 were further resolved to be mixed HPV-16/HPV-31 infections by real-time polymerase chain reaction. The risk of cervical intraepithelial neoplasia associated with HPV-18 infection (0.4-1.7) is substantially lower than with either HPV-16 (3.6-11.0) or HPV-31 (1.8-12.6).

CONCLUSIONS

HPV-31 is contributing significantly to the proportion of women with cervical intraepithelial neoplasia in our population and shows a higher prevalence than HPV-18 in high-grade lesions. The clinical significance of HPV-31 may be underestimated and its continued significance will depend on the level of cross protection offered by the new vaccines.

Human papillomavirus (HPV) related carcinomas of the upper aerodigestive tract

Epidemiologic, clinical, morphologic and molecular evidence show that high risk HPV, particularly type 16, is a prerequisite for some carcinomas of the upper aerodigestive tract (UADT), particularly tonsil and base of tongue. Sexual transmission is an important mode of infection while tobacco use and excessive drinking are not considered risk factors. HPV + tumors are distinct clinically and pathologically. They are more common in young patients (<40 years) with a male to female ratio of 4:1. They usually present as a small or occult primary tumor with advanced neck disease. Microscopically they are non-keratinizing squamous cell carcinomas with basaloid features, excessive mitosis and comedo type necrosis. The tumors have a distinct immunohistochemical profile characterized by strong and diffuse p16 reactivity, low or negative p53 staining and high Ki67 labeling scores. HPV + carcinomas are more radio-sensitive and have a better prognosis than the classical keratinizing SCC of the UADT. An anti-HPV vaccine has recently been made available for prevention of cervical cancer. The impact of the vaccine on the prevalence of HPV related carcinomas of the UADT is currently not known but likely beneficial.

Head and Neck Squamous Cell Cancer: Biology (II) and Translational Methods

The essential steps implicated in carcinogenesis are acquisition of autonomous proliferative signaling; inhibition of growth inhibitory signals; evasion of apoptosis; immortalization; angiogenesis; tissue invasion and metastasis. A considerable progress in understanding the process of carcinogenesis has further stimulated the high throughput translational methods and systems biology approach to revolutionize this field of cancer biology. The era of molecular targeted therapy has dawned and would soon replace the more 'toxic' classical 'broad-spectrum' cancer chemotherapy. This review summarises the steps of carcinogenesis and the concepts involved in translational methods, systems-biology and molecular targeted therapy.

A potent replicative delta-24 adenoviral vector driven by the promoter of human papillomavirus 16 that is highly selective for associated neoplasms

BACKGROUND

Several human epithelial neoplasms are associated with high-risk strains of human papillomavirus (HPV) such as cervical, anorectal, and other carcinomas. For some tumor types the current therapeutic tools are only palliative. Conditionally replicative adenoviruses (CRAds) are promising antineoplastic agents, which also can trigger confined antitumor effects.

METHODS

We constructed a series of CRAds driven by the upstream regulatory promoter region (URR) of an Asian-American variant of HPV-16, which contained different mutations at the E1A region (dl1015 and/or Delta24) and wild-type. All vectors were tested in vitro for viral replication and cytotoxicity. Viral DNA replication and E1A expression were also assessed by quantitative PCR. Finally, we confirmed the antitumoral efficacy of this vector in injected and non-injected xenotransplanted cervical tumors in a murine model for tumor regression and survival studies.

RESULTS

A vector denominated Ad-URR/E1ADelta24 displayed a potent cytopathic effect associated with high selectivity for HPV+ cell lines. We found that the oncolytic effect of this CRAd was comparable to Ad-wt or Ad-Delta24, but this efficacy was significantly attenuated in HPV- cell lines, an effect that was contributed by the URR promoter. Ad-URR/E1ADelta24 was very effective to control tumor growth, in both, injected and non-injected tumors generated with two different HPV+ cell lines.

CONCLUSIONS

CRAd Ad-URR/E1ADelta24 is a highly selective vector for HPV+ cell lines and tumors that preserves the oncolytic efficacy of Ad-wt and Ad-Delta24. Our preclinical data suggest that this vector may be useful and safe for the treatment of tumors induced by HPV, like cervical cancers.

Detection of human papillomavirus in organs of upper genital tract in women with cervical cancer

In this study, we evaluated the presence of human papillomavirus (HPV) DNA in organs of the female upper genital tract, using nine hysterectomy and salpingo-oophorectomy specimens affected by HPV-positive invasive cervical carcinomas, to establish if cervical HPV infection can spread to upper tracts of the female genital system. HPV DNA was evaluated by polymerase chain reaction (PCR) in all cervical carcinomas as well as in all tracts of the genital system. Then, these data were compared with the results obtained from PCR study of five other hysterectomy and salpingo-oophorectomy specimens (control cases). The criteria used for selection of the control cases were informed consent of the patients for research at the time of surgery, absence of neoplasms, absence of any anatomic lesion caused by HPV in cervix, and external genitalia. All selected cases were squamous cervical carcinomas. PCR analysis revealed HPV DNA in all cases of cervical carcinoma. The HPV DNA was detected as weak positivity on PCR analysis in other organs of the genital system. However, the distribution of HPV DNA varied in the various cases and in the different tracts of the same hysterectomy and salpingo-oophorectomy specimen. We believe that the HPV DNA, detected as a weakly positive signal, in the upper genital tract of patients who have a cervical squamous carcinoma could be a reflection of a latent HPV infection, as well as a sign of the existence of micrometastases containing HPV DNA, which cannot be detected by conventional histologic techniques.

A circadian model for viral persistence

Persistently infecting DNA viruses depend heavily on host cell DNA synthesis machinery. Replication of cellular and viral DNA is inhibited by mutagenic stress. It is hypothesized that diurnal regulation of viral DNA replication may occur at the level of cell cycle checkpoints and DNA repair, to protect DNA from exposure to UV light or other mutagens. This highly conserved mechanism is traced back to viruses that persist in prokaryotes and eukaryotes. Inhibition of viral DNA replication and the cell cycle in response to UV light may represent a functional building block in the evolution of circadian-gated DNA replication. Viral DNA replication appears to be closely linked to the circadian clock by interaction of viral promoters, early viral proteins and transcription factors. It is proposed here that under certain conditions viral oncogene expression is phase-shifted relative to that of tumor suppressor and DNA repair genes. The resulting desynchrony of checkpoint controls and DNA repair from diurnal genotoxic exposure produces cyclic periods of suboptimal response to DNA damage. This temporal vulnerability to genotoxic stress produces a "mutator phenotype" with inherent genome instability. The proposed model delineates areas of research with implications for viral pathogenesis and therapeutics.

Novel methods to treat and prevent human papillomavirus infection

The human papillomavirus (HPV), a ubiquitous sexually transmitted virus, is the causative agent for cervical dysplasia and carcinoma worldwide. Current treatment methods primarily utilize ablative and excisional procedures to remove dysplastic, HPV-infected cervical tissue. However, these procedures require intensive cytopathological surveillance and carry inherent risks of bleeding, infection and possible future pregnancy complications. Development of an effective vaccine against HPV would dramatically reduce the need for costly cytological and histological surveillance. HPV represents an ideal candidate for vaccine development, and current research efforts in the realm of prophylactic and therapeutic vaccine design show great promise. A host of various vaccine techniques are currently being developed and tested and, if effective, will have a significant impact on the incidence of cervical dysplasia and carcinoma.

Alteration of cell-cycle regulatory proteins in human oral epithelial cells immortalized by HPV16 E6 and E7

E6 and E7 oncoproteins from high-risk human papillomavirus (HPV) can transform cells in tissue culture and induce tumors in vivo by abrogating the cell-cycle checkpoint. To investigate the impact of HPV16 E6 and E7 on the cell-cycle regulatory machinery in oral epithelial cells, normal human oral epithelial cells were transfected with HPV16 E6 and E7 open reading frames, and alterations in cell-cycle regulatory proteins in cells expressing HPV16 E6 and E7 were analyzed. E6 and E7 expression results in immortalization of oral epithelial cells. E7 inactivates retinoblastoma protein (Rb) by forming complexes with hypophosphorylated Rb in immortalized oral epithelial cells. P53 and P21 protein levels were increased in immortalized cells compared to normal primary oral epithelial cells. Cyclin D1-cell-cycle-dependent kinase 4 binary association is disrupted in immortalized oral epithelial cells. These results indicate that E7 plays an important role in abrogation of cell-cycle regulation in oral epithelial cells, with E6 having a smaller impact. This suggests that the pathogenesis of HPV in oral epithelial cells differs from that in cervical epithelial cells.

Cell Cycle Regulators p105, p107, Rb2/p130, E2F4, p21CIP1/WAF1, Cyclin A in Predicting Cervical Intraepithelial Neoplasia, High-Risk Human Papillomavirus Infections and Their Outcome in Women Screened in Three New Independent States of the Former Soviet Union

BACKGROUND

The growth-controlling functions of the high-risk human papillomaviruses (HPV) depend on their ability to interact with several cellular proteins, including the key regulatory proteins of the cell cycle. We have examined the value of cell cycle regulatory proteins as predictors of the intermediate end point markers in cervical carcinogenesis: (a) grade of cervical intraepithelial neoplasia (CIN), (b) high-risk HPV type, (c) clearance/persistence of high-risk HPV, and (d) disease outcome in women participating in a multicenter follow-up study in three New Independent States countries.

METHODS

Totally, 232 biopsy samples tested high-risk HPV-positive and/or Papanicolaou smear-positive women were immunohistochemically stained for the following cell cycle markers: p105, p107, p130, E2F4, p21(CIP1/WAF1/SDI1), cyclin A, and Ki-67. In addition, apoptotic index (AI) and mitotic index (MI) were determined in H&E-stained sections. Prospective follow-up data were available to disclose the clinical and virological outcome of the lesions.

RESULTS

The expression of Ki-67, p21(CIP1/WAF1/SDI1), and cyclin A and AI and MI values were markedly increased in high-grade lesions, but only MI was an independent predictor of CIN3 in multivariate analysis. Cyclin A was the only independent predictor of high-risk HPV (odds ratio, 1.09; 95% confidence interval, 1.01-1.18; P = 0.021), exceeding the predictive power of CIN grade and high-grade squamous intraepithelial lesion Papanicolaou smears. None of these markers provided any useful predictive information as to the clinical and virological outcomes during the follow-up. Highly significant correlations (P = 0.0001) were found between AI and MI as well as between MI and cyclin A, Ki-67 and p21(CIP1/WAF1/SDI1), Ki-67 and cyclin A, and p21(CIP1/WAF1/SDI1) and cyclin A followed by that between p105 and cyclin A (P = 0.001) and p105 and p130 (P = 0.002).

CONCLUSIONS

All tested factors related to cell cycle were increased, but only MI and cyclin A was an independent predictor of CIN3 and high-risk HPV carriage, respectively.

Human papillomavirus (HPV)-related oropharyngeal nonkeratinizing squamous cell carcinoma: characterization of a distinct phenotype

We have recently shown that HPV-positive tonsillar carcinoma in young patients exhibits nonkeratinizing basaloid morphology and a characteristic immunophenotype. The purpose of this study was to review a large number of cases of oropharyngeal carcinomas, in all age groups, and to identify tumors with nonkeratinizing morphology. Using polymerase chain reaction (PCR) the prevalence and type of HPV DNA was determined in representative cases and in a control group of conventional keratinizing squamous cell carcinomas. The tumors were further characterized with a panel of immunohistochemical stains. A total of 235 carcinomas were reviewed; 141 of the tonsils and 94 in the base of tongue. Ninety (36%) of the tonsillar and 30 (32%) of the base of tongue carcinomas were nonkeratinizing (NKCa) with basal cell features; the rest were classical keratinizing squamous cell carcinomas (KSCC). HPV DNA, particularly type 16, was identified in 10 (100%) of 10 of NKCA and in only 2 (20%) of 10 of KSCC (P = .0014). NKCas were strongly reactive to p16 antibodies while KSCC showed weak and focal reactivity. Higher Ki67 and lower p53 staining scores were observed in NKCa as compared to KSCC. It is concluded that NKCa of the tonsils and base of tongue is a distinct subtype of squamous cell carcinoma of the head and neck with high prevalence of HPV DNA and a characteristic immunophenotype.

Human polyomavirus BKV transcriptionally activates DNA methyltransferase 1 through the pRb/E2F pathway

Many DNA tumor virus oncogenes are capable of activating and highjacking the host cell's DNA replication machinery for its own reproduction purposes through targeting and inactivation of the retinoblastoma pocket protein family. Pocket proteins function to regulate cell cycle progression and DNA synthesis through inhibitory interactions with the E2F transcription factors. The interaction of viral oncogenes with the pocket proteins is crucial for their transforming activity. We recently demonstrated that the DNA methyltransferase 1 (DNMT1) gene is an E2F target gene that is transcriptionally activated in cells lacking the retinoblastoma gene (Rb-/-). Overexpression of DNMT1 is implicated in tumor suppressor gene hypermethylation which is associated with tumorigenesis. Given that viral oncogenes potently stimulate E2F activity, we hypothesized that viral infection might activate DNMT1 and thereby promote transformation. Herein, we demonstrate that DNMT1 is strongly activated by the human polyomavirus BKV large T antigen (TAg) and adenovirus E1a. Viral oncogene mutants incapable of binding the pocket proteins are ineffective at activating DNMT1 compared to their wild-type counterparts. Additionally, mutation of the E2F sites within the DNMT1 promoters dramatically abrogates transcriptional activation. These data suggest that viral induction of DNMT1 through modulation of the pRB/E2F pathway may be involved in viral transformation.

Human papilloma virus (HPV) is rarely detected in malignant melanomas of sun sheltered mucosal membranes

Human papillomavirus (HPV) has been associated with some types of human cancer. The aim of this study was to investigate if HPV could be associated with human primary malignant melanoma in non sun-exposed body areas like mucous membranes. Through the Swedish National Cancer Registry, in compliance with the rules of the Human Ethical Committee, histopathological specimens were collected from different pathological laboratories throughout Sweden. The histopathological diagnosis was reviewed, and from 45 primary melanomas, tumour tissue was micro-dissected and analysed further. A protocol for detection of HPV DNA using general HPV primers GP5 + /GP6+ or CPI/IIG, which together identify 36 different HPV subtypes, was developed. This protocol could detect presence of HPV DNA in less than 10 ng of DNA of a control cell that contained 1-2 copies of HPV type 16/cell. Before HPV testing the melanoma samples were examined for amplifiable DNA by a beta-microglobulin PCR and 39 were positive. Thirty-five of these could be evaluated for HPV DNA and no samples were positive according to all five defined criteria for HPV positivity although two were positive according to 4/5 criteria. In conclusion, HPV is rarely detected in primary malignant melanomas of non-sun exposed body areas.

Protein profiling and identification of modulators regulated by human papillomavirus 16 E7 oncogene in HaCaT keratinocytes by proteomics

OBJECTIVES

Viral oncogenes E6 and E7 are selectively retained and expressed in carcinoma cells infected with human papillomavirus type 16 and cooperated with each other in immortalization and transformation of primary keratinocytes. This study was performed to identify proteins to be bound or modulated by high risk HPV E7 oncogene by using a proteomics.

METHODS

HaCaT normal keratinocyte was prepared to establish a stable cell line expressing E7. The E7-affinity column was also prepared to obtain E7-interacting proteins. In order to search the target molecules modulated by E7 expression, we used 2-dimensional electrophoresis and matrix-assisted laser desorption/ionization time of flight (MALDI/TOF) mass spectrometry. Pull down assay was also performed in order to confirm the E7-interacting proteins.

RESULTS

We identified 28 spots that are modulated by E7 in HaCaT/E7 using 2-dimensional electrophoresis (2-DE) and MALDI/TOF mass spectrometry. Proteomics analyses showed that actin and leukocyte elastase inhibitor were down-regulated, whereas stress-induced phosphoprotein 1, CD2 binding protein 1, catalase, T-complex protein 1, Ku70-binding protein, heat shock 60 kDa protein 1, G1/S-specific cyclin E1 and peroxiredoxin 2 were up-regulated. Western blot revealed that heat shock 60 kDa protein, catalase and peroxiredoxin 2 were also up-regulated. Pull down assay also showed that leukocyte elastase inhibitor (LEI) and Ku70-binding protein were bound to the E7 oncoprotein. By using E7-affinity column and 2-DE/MALDI-TOF, 22 spots were found to interact with E7 recombinant protein. MG11-like proteins, livin inhibitor-of-apoptosis, protein serine kinase c17, CD2 binding protein 1, cyclin E1, TATA box binding protein-associated factor and uridine-cytidine kinase 2 were up-regulated by E7 oncogene and also bound to E7 oncoprotein.

CONCLUSIONS

It is presumed that E7 can influence cell status by modulating the factors related to cell signaling, apoptosis and cell cycle regulation.

HPV infection in adolescents: natural history, complications, and indicators for viral typing

Human papillomavirus (HPV) is the most common sexually transmitted disease in both men and women. Prevalence rates are the highest for adolescents. Despite the high prevalence rates, sequelae of genital warts, dysplasia, and cancer are rare developments. Knowledge about the natural history, virology, and cancerous transformation has lead to improved viral detection, including the use of HPV DNA detection tests, screening efforts for HPV-related precancerous and cancerous lesions, and clinical interventions and treatments, including both therapeutic and prophylactic vaccinations.

Prevalence of high-risk human papillomavirus DNA in nonkeratinizing (cylindrical cell) carcinoma of the sinonasal tract: a distinct clinicopathologic and molecular disease entity

Carcinomas of the nose and paranasal sinuses are a heterogeneous group of neoplasms that differ histologically, biologically, and clinically. Some of these tumors are known to harbor high-risk human papillomavirus (HPV) DNA. In an attempt to identify specific phenotypes associated with HPV infection, 39 cases of sinonasal carcinomas were evaluated by PCR for the presence of HPV DNA. The tumors were also studied with a panel of immunohistochemical stains, including p16, p53, and Ki-67 antibodies. Twenty-one cases were identified as keratinizing squamous cell carcinoma (KSCC) with a male-to-female ratio of 3:1. Eight cases were nonkeratinizing (cylindrical cell) carcinoma (NKCa) with a male-to-female ratio of 1:1. Ten cases were sinonasal undifferentiated carcinoma (SNUC), and 9 of these patients were men. HPV DNA, particularly type 16, was detected in 9 cases: 4 of 21 (19%) of KSCC, 4 of 8 (50%) of NKCa, and 1 of 10 (10%) of SNUC. In addition to a higher prevalence of HPV DNA in NKCa, the tumors also showed a distinct immunophenotype characterized by strong and diffuse staining for p16, high labeling scores for Ki-67, and negative or low reactivity to p53. On the other hand, KSCC and SNUC were either negative or weakly reactive to p16 antibodies. KSCC cases were more likely to be positive and more strongly reactive to p53 stain. Unlike KSCC, SNUC had high Ki-67 labeling scores. These observations suggest that NKCa of the sinonasal tract is a distinct histopathologic and molecular disease entity, which should be added to the list of upper aerodigestive tract tumors with strong etiologic relationship to high risk HPV.

p16(INK4A) expression is related to grade of cin and high-risk human papillomavirus but does not predict virus clearance after conization or disease outcome

The role of p16(INK4A) as a marker of HR-HPV and in the diagnosis of CIN has been well established, but its predictive value in the clearance of the virus after CIN treatment and its use as a prognostic marker of cervical cancer has not been studied. A series of 302 archival samples, including 150 squamous cell carcinomas (SCCs) and 152 CIN lesions, were subjected to immunohistochemical staining for p16(INK4A) and HPV testing using PCR with three primer sets (MY09/11, GP5/GP6, SPF). Follow-up data were available of 88 SCC patients, and 67 of the CIN lesions had been followed-up with serial PCR after conization. HR-HPV types were closely associated with CIN (OR 19.12; 95%CI 2.31-157.81) and SCC (OR 27.25; 95%CI 3.28-226.09). There was a significant linear relationship between the lesion grade and intensity of p16(INK4A) staining (p = 0.0001). The expression of p16(INK4A) was also closely related to HR-HPV (p = 0.0001). p16(INK4A) staining was a 100% specific indicator of CIN, with 100% PPV, and showed 83.5% sensitivity and 80.1% PPV in detecting HR-HPV. However, p16(INK4A) staining did not predict clearance/persistence of HR-HPV after treatment of CIN. Similarly, despite a slightly more favorable survival in women with strong/intense p16(INK4A) staining in univariate analysis, p16(INK4A) expression was not an independent prognostic predictor in multivariate survival (Cox) analysis. After adjustment for p16(INK4A) staining, HR-HPV, histological grade, International Federation of Gynecology and Obstetrics (FIGO) stage, and age, only the last two were significant prognostic predictors (p = 0.0001 and p = 0.003, respectively). The present data confirm the role of p16(INK4A) as a highly specific marker of CIN and HR-HPV type, but expression of this protein does not seem to be of any prognostic value in cervical cancer or in predicting the clearance of HR-HPV after treatment of CIN. We speculate that different subgroups of cervical cancer are characterized by aberrant p16(INK4A)/cyclin D/Rb pathways that are due to different mechanisms that can be mutually exclusive.

Resistance to apoptosis of HPV 16-infected laryngeal cancer cells is associated with decreased Bak and increased Bcl-2 expression

Human papillomavirus type 16 (HPV 16) plays an etiological role in human laryngeal carcinoma. Apoptosis is closely associated with various biological processes including oncogenesis. This study investigated how HPV 16 oncoproteins E6 and E7 affect apoptosis in human laryngeal cancer cells. We established two human laryngeal cancer cell lines that expressed HPV 16 E6 and E7, respectively. Using these two cell lines, we found that both E6 and E7 exhibited an inhibitive effect on apoptosis induced by tumor necrosis factor alpha and cycloheximide. In both transfected cell lines, the expression of pro-apoptotic Bak was reduced and that of anti-apoptotic Bcl-2 was over-expressed. However, the expression of caspase-3 and caspase-8 was not significantly different between the E6- and E7-transfected cells and the control cells without HPV 16. p53 Protein was not detected in either the transfected or the non-transfected cells. Our study indicates that: (1) HPV 16 E6 and E7 oncoproteins are capable of inhibiting apoptosis in laryngeal squamous carcinoma cells; (2) the mechanism modulated by E6 and E7 involves the over-expression of Bcl-2 and the down-regulation of Bak; (3) the anti-apoptotic pathway is not related to the level of p53, caspase-3, or caspase-8. These results suggest that the dysregulation of apoptotic molecules Bak and Bcl-2 by HPV 16 E6 and E7 plays a role in the prolongation of cell survival, which may subsequently contribute to the development of human laryngeal cancer.