Papillomavirus infections--a major cause of human cancers

Tumourigenesis driven by the human papillomavirus type 16 Asian-American e6 variant in a three-dimensional keratinocyte model

Infection with a transforming human papillomavirus (HPV) such as type 16 (of species Alphapapillomavirus 9) causes ano-genital and oral tumours via viral persistence in human squamous cell epithelia. Epidemiological studies showed that the naturally occurring HPV16 Asian-American (AA) variant (sublineage D2/D3) is found more often than the European Prototype (EP) (sublineage A1) in high-grade cervical neoplasia and tumours compared to non-cancer controls. Just three amino acid changes within the early gene, E6, of HPV16 AA have been linked to this augmented tumourigenicity. The AAE6 variant's greater immortalizing and transforming potential over EPE6 has recently been confirmed in retrovirally-transduced keratinocytes expressing the E6 gene only. However, the tumourigenic role of the full-length viral genome of HPV16 has not yet been addressed with regard to these E6 variants. To investigate this process in the context of these two HPV16 E6 genotypes, an organotypic tissue culture model was used to simulate the HPV infectious life cycle. The AAE6 variant demonstrated an enhanced ability over EPE6 to drive the viral life cycle toward tumourigenesis, as evidenced phenotypically—by a more severe grade of epithelial dysplasia with higher proliferation and deregulated differentiation, and molecularly—by high viral oncogene E6 and E7 expression, but lack of productive viral life cycle markers. In contrast, EPE6 had low E6 and E7 but high E1∧E4 expression, indicative of a productive life cycle. We suggest increased viral integration into the host genome for AAE6 as one possible mechanism for these observed differences from EPE6. Additionally, we found downstream effects on immortalization and host innate immune evasion. This study highlights how minor genomic variations in transforming viruses can have a significant affect on their tumourigenic ability.

Age-specific prevalence of human papilloma virus infection among Nigerian women

BACKGROUND

Inconsistent trends in HPV prevalence by age have been described in Africa. We examined the age prevalence pattern and distribution of 37 HPV-DNA types among urban Nigerian women.

METHODS

The study population was a sample of 278 women who presented to cervical cancer screening programs in Abuja, Nigeria, between April and August 2012. Using a nurse administered questionnaire, information on demographic characteristics and risk factors of cervical cancer was collected and samples of cervical exfoliated cells were obtained from all participants. Roche Linear Array HPV Genotyping Test® was used to characterize prevalent HPV and log-binomial regression models were used to examine the association between potential correlates and the prevalence of HPV infection.

RESULTS

The mean age (SD) of the women enrolled was 38 (8) years. The overall prevalence of HPV was 37%. HPV 35 was the most prevalent HPV type in the study population. Among women age ≤ 30 years, 52% had HPV infection compared to 23% of those women who were older than 45 years (p = 0.006). We observed a significant linear association between age and the prevalence of HPV infections. The prevalence ratio (PR) and 95% confidence interval (CI) was 2.26 (1.17, 4.34) for any HPV infection, 3.83 (1.23, 11.94) for Group 1 HPV (definite carcinogens), and 2.19 (0.99, 4.84) for Group 2a or 2b HPV (probable or possible carcinogens) types, among women aged 18-30 years, compared to women who were older than 45 years.

CONCLUSION

The prevalence of HPV infection was highest among younger women and decreased steadily with age among this population of urban Nigerian women.

Clinical impact of de-regulated Notch-1 and Notch-3 in the development and progression of HPV-associated different histological subtypes of precancerous and cancerous lesions of human uterine cervix

BACKGROUND

Cervical cancer is the leading cause of cancer related deaths among women in India. Limited reports are available for Notch-1 and Notch-3 protein in cervical carcinoma, which play crucial role in cell proliferation, differentiation, and apoptosis.

METHODS

This study was designed to evaluate the role of Notch-1 and Notch-3 with context to HPV infection in cervical carcinoma. A total of 168 tissue biopsy samples comprising of tumor specimens (n = 98), precancer (n = 30) and non-neoplastic cervical tissues (n = 40) were screened for HPV infection by PCR and expression of Notch-1 and Notch-3 protein by Immunohistochemistry and Immunoblotting.

RESULTS

80% (24/30) were found to be positive for HPV in precancer and 86.7% (85/98) in cancer patients. Notch-1 expression of precancer and cancer cases was found to be significantly down-regulated with severity of disease in nuclear (3.43±0.29; 2.04±0.19, p = 0.0001, p = 0.0001) and cytoplasm (3.07±0.29; 2.29±0.17, p = 0.0001, p = 0.0001) obtained from different stages as compared to normal cervix tissue (5.40±0.19, 4.97±0.15; p<0.001; p<0.001). However, Notch-3 expression of above cases was significantly up-regulated with severity of disease and showed intense nuclear (4.17±0.39; 4.74±0.18, p = 0.0001, p = 0.0001) and cytoplasm (3.67±0.36; 4.48±0.18, p = 0.0001, p = 0.0001) of different stages as compared to normal cervix tissue (0.95±0.20, 0.70±0.20; p<0.001; p<0.001) respectively.

CONCLUSIONS

These findings suggest that Notch-1 and Notch-3 may play an important role with synergistic effect of HPV in regulating development and proliferation of cervical cancer through the deregulation of Notch signalling. This study also shows the clinical utility of both proteins which may be used as predictable biomarkers in diagnosing different histological sub-types of HPV associated cervical cancer. Nevertheless, abnormal activation of this pathway may provide legitimate targets for cervical cancer therapy.

HPV-associated lung cancers: an international pooled analysis

Human papillomavirus (HPV) is the etiologic risk factor for cervical cancer. Some studies have suggested an association with a subset of lung tumors, but the etiologic link has not been firmly established. We performed an international pooled analysis of cross-sectional studies (27 datasets, n = 3249 patients) to evaluate HPV DNA prevalence in lung cancer and to investigate viral presence according to clinical and demographic characteristics. HPV16/18 were the most commonly detected, but with substantial variation in viral prevalence between geographic regions. The highest prevalence of HPV16/18 was observed in South and Central America, followed by Asia, North America and Europe (adjusted prevalence rates = 22, 5, 4 and 3%, respectively). Higher HPV16 prevalence was noted in each geographic region compared with HPV18, except in North America. HPV16/18-positive lung cancer was less likely observed among White race (adjusted odds ratio [OR] = 0.33, 95% confidence interval [CI] = 0.12-0.90), whereas no associations were observed with gender, smoking history, age, histology or stage. Comparisons between tumor and normal lung tissue show that HPV was more likely to be present in lung cancer rather than normal lung tissues (OR = 3.86, 95% CI = 2.87-5.19). Among a subset of patients with HPV16-positive tumors, integration was primarily among female patients (93%, 13/14), while the physical status in male cases (N = 14) was inconsistent. Our findings confirm that HPV DNA is present in a small fraction of lung tumors, with large geographic variations. Further comprehensive analysis is needed to assess whether this association reflects a causal relationship.

Complete genome sequence of canine papillomavirus type 11

Papillomaviruses with the features of epitheliotropic, nonenveloped, circular, and double-stranded DNA belong to the family Papillomaviridae, which contributes to benign and malignant tumors in humans and animals. We report the whole-genome sequence of canine papillomavirus type 11 found at a pigmented plaque located on the skin of a mixed-breed bloodhound.

Enhanced therapeutic effects conferred by an experimental DNA vaccine targeting human papillomavirus-induced tumors

Human papillomavirus (HPV) infection is responsible for all cervical cancer cases, other anogenital cancers, and head and neck tumors. The epidemiological relevance of HPV-induced tumors reinforces the need for the development of therapeutic antitumor vaccines. Clinical trials with different vaccine formulations, particularly DNA vaccines, have provided promising results but have still been unable to achieve the immunogenicity required for use in infected patients. In experimental conditions, anticancer HPV-specific vaccines induced E7-specific CD8(+) T-cell responses but did not confer full therapeutic antitumor protection in mice with transplanted HPV-expressing TC-1 cells, which are the most frequently used nonclinical protection correlate for antitumor effects. Our group has developed a DNA vaccine strategy based on the fusion of HPV oncoproteins to the herpes virus gD protein. This vaccine promoted the induction of antigen-specific cytotoxic CD8(+) T-cell responses and partial antitumor therapeutic effects based on the blockade of coinhibitory signals and the enhancement of coactivation mechanisms. In the present study, we report conditions leading to full therapeutic antitumor effects using the TC-1 cell murine model after a single vaccine dose. The combination of a coadministered plasmid encoding IL-2, optimization of the coding sequence for mammalian cells, and the use of different delivery routes resulted in enhancements of the E7-specific cytotoxic CD8(+) T-cell responses and full therapeutic protection under experimental conditions. The combination of these strategies augmented the potency of the DNA vaccine formulation to levels not previously achieved by other therapeutic antitumor vaccines under similar experimental conditions, including some that have been taken to clinical trials.

A very rare case of HPV-53-related cervical cancer, in a 79-year-old woman with a previous history of negative Pap cytology

The introduction of organized cervical cancer (CC) screening programs has drastically reduced the prevalence of CC. However the incidence is still too high, especially among elderly women. All guidelines strongly recommend a regular Papanicolaou (Pap) testing for young and middle-aged patients. On the other hand, many international professional societies no longer advise screening in women who have undergone hysterectomy, and in women aged 65 years and above, who have a previous history of regular Pap smears. Here we report the case of poorly differentiated CC, involving the pelvic lymph nodes and urinary bladder, occurring in a 79-year-old woman who regularly underwent Pap tests, with no reported cytological abnormalities. In this very rare case, the CC cells, as well as cells from metastatic lymph nodes and cells from urinary specimens, molecularly showed human papilloma virus (HPV)-53. With the limitations of a single case, this report brings important information to prevent CC in elderly patients: the utility of molecular tests to increase sensitivity of Pap smears in postmenopausal women; the importance of HPV-53 as one of the four "emergent" genotypes having a possible role in oncogenesis; and the presence of HPV-53 in lymph node metastases from cervical carcinoma, which would support the role of this virus in the maintenance of malignant status.

Investigation of the role of major respiratory viruses in the aetiology of nasal polyps using polymerase chain reaction technique

OBJECTIVE

We aimed to identify the role of major respiratory viruses in the aetiology of human nasal polyps using polymerase chain reaction technique.

METHODS

Thirty patients with nasal polyps and a group of 20 healthy patients (control group) were included in this study. Mucosa was obtained from the polyps of patients with nasal polyposis and from the middle turbinate of the control group patients by means of biopsy. The samples were stored at -80 °C until molecular analysis by polymerase chain reaction was carried out.

RESULTS

In the control group, the human coronavirus and human rhinovirus were diagnosed in one of the patients and the human respiratory syncytial virus in another. In the group with nasal polyposis, the influenza B virus was identified in one of the patients and the human coronavirus in another.

CONCLUSION

The results did not demonstrate a statistically significant relationship between nasal polyposis and respiratory viruses.

E2 proteins of high risk human papillomaviruses down-modulate STING and IFN-κ transcription in keratinocytes

In the early stages of human papillomavirus (HPV) infection, the viral proteins elicit specific immune responses that can participate to regression of ano-genital lesions. HPV E6 protein for instance can reduce type I interferon (IFN) including IFN-κ that is involved in immune evasion and HPV persistence. To evaluate the role of E2 protein in innate immunity in HPV16-associated cervical lesions, genome-wide expression profiling of human primary keratinocytes (HPK) transduced by HPV16 E2 was investigated using microarrays and innate immunity associated genes were specifically analyzed. The analyses showed that the expression of 779 genes was modulated by HPV16E2 and 92 of them were genes associated with innate immunity. Notably IFN-κ and STING were suppressed in HPK expressing the E2 proteins of HPV16 or HPV18 and the trans-activation amino-terminal domain of E2 was involved in the suppressive effect. The relationship between STING, IFN-κ and interferon stimulated genes (ISGs) in HPK was confirmed by gene silencing and real time PCR. The expression of STING and IFN-κ were further determined in clinical specimens by real time PCR. STING and IFN-κ were down-modulated in HPV positive low grade squamous intraepithelial lesions compared with HPV negative controls. This study demonstrates that E2 proteins of high risk HPV reduce STING and IFN-κ transcription and its downstream target genes that might be an immune evasion mechanism involved in HPV persistence and cervical cancer development.

Current views and perspectives on classification of squamous intraepithelial lesions of the head and neck

The current state in the field of classifying oral and laryngeal precursor lesions, as proposed in the WHO 2005 Blue Book is not ideal. The results of various inter-observer studies have shown that the currently used grading systems, with different basic concepts and different terminology, cannot continue to be reliably used in the future. The different etiology of cervical and head and neck precursor lesions requires a classification designed to cater to the specificities of the head and neck region. Trying to harmonize different classifications of the oral and laryngeal precursor lesions, we have proposed four crucial steps to set up a unified classification of squamous intraepithelial lesions (SILs): (a) the classification should contain two grades, low-grade and high-grade lesions and, specifically for the larynx, an additional grade-carcinoma in situ (CIS) which must be separated from high-grade laryngeal SILs; (b) the terminology should be unified; our preference is for the term SIL over squamous intraepithelial neoplasia; (c) all leading morphological criteria for low- and high-grade lesions, as well as for CIS, should be clearly defined; (d) agreement between clinicians and pathologists should be achieved on the most appropriate choice of treatment of different grades of SILs in separate head and neck areas.

[Squamous cell lesions of the urinary bladder]

BACKGROUND

Squamous cell carcinoma (SCC) and transitional carcinoma with squamous differentiation (SCC/TCC) are rare in western countries. Chronic inflammation and irritation of the urothelium are common risk factors for the development of SCC and TCC/SCC. Tumour biology of squamous cell cancer and precancerous squamous lesions is different from transitional cell cancer (TCC). Recent advances in molecular analysis of benign and malignant squamous cell lesions indicate that they are closely associated and might lead to improved bladder cancer subclassification in the future.

AIM

At present, the clinical management and therapy of SCC remains challenging, as scientific evidence based on prospective clinical trials is not available. We performed an analysis of available literature on natural history, treatment, and prognosis of SCC, SCC/TCC and metaplastic lesions. Furthermore, recent findings in molecular cancer biology are discussed with a focus on their relevance for SCC carcinogenesis.

Transactivation of bad by vorinostat-induced acetylated p53 enhances doxorubicin-induced cytotoxicity in cervical cancer cells

Vorinostat (VOR) has been reported to enhance the cytotoxic effects of doxorubicin (DOX) with fewer side effects because of the lower DOX dosage in breast cancer cells. In this study, we investigated the novel mechanism underlying the synergistic cytotoxic effects of VOR and DOX co-treatment in cervical cancer cells HeLa, CaSki and SiHa cells. Co-treatment with VOR and DOX at marginal doses led to the induction of apoptosis through caspase-3 activation, poly (ADP-ribose) polymerase cleavage and DNA micronuclei. Notably, the synergistic growth inhibition induced by the co-treatment was attributed to the upregulation of the pro-apoptotic protein Bad, as the silencing of Bad expression using small interfering RNA (siRNA) abolished the phenomenon. As siRNA against p53 did not result in an increase in acetylated p53 and the consequent upregulation of Bad, the observed Bad upregulation was mediated by acetylated p53. Moreover, a chromatin immunoprecipitation analysis showed that the co-treatment of HeLa cells with VOR and DOX increased the recruitment of acetylated p53 to the bad promoter, with consequent bad transactivation. Conversely, C33A cervical cancer cells containing mutant p53 co-treated with VOR and DOX did not exhibit Bad upregulation, acetylated p53 induction or consequent synergistic growth inhibition. Together, the synergistic growth inhibition of cervical cancer cell lines induced by co-treatment with VOR and DOX can be attributed to the upregulation of Bad, which is induced by acetylated p53. These results show for the first time that the acetylation of p53, rather than histones, is a mechanism for the synergistic growth inhibition induced by VOR and DOX co-treatments.

Prevalence of human papillomavirus infection in the oropharynx and urine among sexually active men: a comparative study of infection by papillomavirus and other organisms, including Neisseria gonorrhoeae, Chlamydia trachomatis, Mycoplasma spp., and Ureaplasma spp

Background

Oropharyngeal squamous cell carcinoma (OSCC) has shown a gradual increase in male predominance due to the increasing incidence of human papillomavirus (HPV)-associated OSCC. However, the mode of HPV transmission to the oral cavity is poorly understood, and little is known about the epidemiology of oral HPV infection in men. The prevalence rates of HPV, Neisseria gonorrhoeae, Chlamydia trachomatis, Mycoplasma spp., and Ureaplasma spp. were compared in the oropharynx (oral cavity) and urine of male Japanese patients attending a sexually transmitted disease clinic.

Methods

The study population consisted of 213 men aged 16 – 70 years old (mean: 34.4 years old). Oropharyngeal gargles and urine were collected, and sedimented cells were preserved in liquid-based cytology solution. After DNA extraction, β-globin and infectious organisms were analyzed by a PCR-based method. The HPV genotype was determined by HPV GenoArray test.

Results

β-Globin was positive in 100% and 97.7% of oral and urine samples, respectively. HPV detection rates were 18.8% and 22.1% in oral and urine samples, respectively, suggesting that the prevalence of HPV infection in the oral cavity was similar to that in the urinary tract. N. gonorrhoeae was more prevalent in oral (15.6%) than urine samples (9.1%), whereas C. trachomatis was detected more frequently in urine (15.9%) than oral samples (4.2%). The detection rates of M. genitalium, M. hominis, and Ureaplasma spp. were 5.2%, 10.3%, and 16.0% in oral samples, and 7.7%, 6.3%, and 19.2% in urine, respectively. There were no significant differences in the detection rates of Mycoplasma spp. and Ureaplasma spp. between anatomical locations. The distribution of HPV types were similar in oral and urine samples, and HPV16 was the most common type. The majority of men with HPV infection in both the oral cavity and urine had concordant oral and urinary HPV infection. The presence of urinary HPV infection was an independent risk factor of oral HPV infection, with an odds ratio of 3.39 (95% CI: 1.49 – 7.71), whereas oral gonococcal infection was inversely correlated with oral HPV infection (odds ratio: 0.096; 95% CI: 0.01 – 0.77).

Conclusions

Oral HPV infection commonly occurs in sexually active men, and is significantly correlated with urinary HPV infection.

A metabolomics investigation into the effects of HIV protease inhibitors on HPV16 E6 expressing cervical carcinoma cells

Recently, it has been reported that anti-viral drugs, such as indinavir and lopinavir (originally targeted for HIV), also inhibit E6-mediated proteasomal degradation of mutant p53 in E6-transfected C33A cells. In order to understand more about the mode-of-action(s) of these drugs the metabolome of HPV16 E6 expressing cervical carcinoma cell lines was investigated using mass spectrometry (MS)-based metabolic profiling. The metabolite profiling of C33A parent and E6-transfected cells exposed to these two anti-viral drugs was performed by ultra performance liquid chromatography (UPLC)-MS and gas chromatography (GC)-time of flight (TOF)-MS. Using a combination of univariate and multivariate analyses, these metabolic profiles were investigated for analytical and biological reproducibility and to discover key metabolite differences elicited during anti-viral drug challenge. This approach revealed both distinct and common effects of these two drugs on the metabolome of two different cell lines. Finally, intracellular drug levels were quantified, which suggested in the case of lopinavir that increased activity of membrane transporters may contribute to the drug sensitivity of HPV infected cells.

The human papillomavirus E7 proteins associate with p190RhoGAP and alter its function

Using mass spectrometry, we identified p190RhoGAP (p190) as a binding partner of human papillomavirus 16 (HPV16) E7. p190 belongs to the GTPase activating protein (GAP) family and is one of the primary GAPs for RhoA. GAPs stimulate the intrinsic GTPase activity of the Rho proteins, leading to Rho inactivation and influencing numerous biological processes. RhoA is one of the best-characterized Rho proteins and is specifically involved in formation of focal adhesions and stress fibers, thereby regulating cell migration and cell spreading. Since this is the first report that E7 associates with p190, we carried out detailed interaction studies. We show that E7 proteins from other HPV types also bind p190. Furthermore, we found that conserved region 3 (CR3) of E7 and the middle domain of p190 are important for this interaction. More specifically, we identified two residues in CR3 of E7 that are necessary for p190 binding and used mutants of E7 with mutations of these residues to determine the biological consequences of the E7-p190 interaction. Our data suggest that the interaction of E7 with p190 dysregulates this GAP and alters the actin cytoskeleton. We also found that this interaction negatively regulates cell spreading on a fibronectin substrate and therefore likely contributes to important aspects of the HPV life cycle or HPV-induced tumorigenesis.

IMPORTANCE

This study identifies p190RhoGAP as a novel cellular binding partner for the human papillomavirus (HPV) E7 protein. Our study shows that a large number of different HPV E7 proteins bind p190RhoGAP, and it identifies regions in both E7 and p190RhoGAP which are important for the interaction to occur. This study also highlights the likelihood that the E7-p190RhoGAP interaction may have important biological consequences related to actin organization in the infected cell. These changes could be an important contributor to the viral life cycle and during progression to cancer in HPV-infected cells. Importantly, this work also emphasizes the need for further study in a field which has largely been unexplored as it relates to the HPV life cycle and HPV-induced transformation.

Increased exosomal microRNA-21 and microRNA-146a levels in the cervicovaginal lavage specimens of patients with cervical cancer

Well-run screening programs for cervical cancer in the population at risk have been shown to result in a sharp decrease in the incidence and mortality of cervical cancer in a number of large populations. Expression patterns of a recently identified biomarker family, microRNA, appear to be characteristic of tumor type and developmental origin. Several tumors have been reported to actively release exosomes carrying microRNAs. The present study has determined the association of microRNAs with cervical cancer-derived exosomes. The cervical cancer-derived exosomes were enriched in the cervicovaginal lavages specimens and the abundance of exosomes and exosomal microRNAs was detected by electron microscopy, western blot analysis, RT-qPCR and microRNA target reporter vector. The microRNA-21 and microRNA-146a, which were up-regulated in cervical cancer patients, were associated with the high levels of cervical cancer-derived exosomes. In conclusion, we demonstrated the abundance of exosomes in the cervicovaginal lavage specimens of women with cervical cancer. Furthermore, our results indicated that abnormally high levels of microRNA-21 and microRNA-146a existed in the cervical cancer-derived exosomes and the two microRNAs were functional in 293T cells.

Human keratinocyte cultures in the investigation of early steps of human papillomavirus infection

Human papillomaviruses (HPVs) are non-enveloped DNA viruses that are highly tropic for mucosal and cutaneous epithelia. The HPV life cycle is tightly linked to epithelial cell differentiation, where HPVs only infect the basal proliferating keratinocytes, and progeny virus assembly and release only occurs in differentiated upper-layer keratinocytes. Therefore, human keratinocyte monolayer cultures provide a useful model to study the early stages of HPV infection. However, previous reports have shown some conflicting results of virus-host interactions during HPV entry, which may be partly attributable to the different cell culture models used to examine these steps of HPV infection. Thus, there is a need to have a standardized in vitro model system to study virus-host interactions during HPV entry. Here, we describe the three most widely accepted keratinocyte models for studying HPV infection: primary human foreskin keratinocytes, normal immortalized keratinocytes, and transformed HaCaT keratinocytes. We also describe methods to genetically manipulate these cells, enabling the study of candidate host genes that may be important during HPV infection. Lastly, we outline simple and robust methods to assay HPV infectivity, which can be used to determine whether knockdown or overexpression of a particular gene affects HPV entry.

Human papillomavirus genotyping and integration in ovarian cancer Saudi patients

Background

Human papillomavirus (HPV) is associated with different malignancies but its role in the pathogenesis of ovarian cancer is controversial. This study investigated the prevalence, genotyping and physical state of HPV in ovarian cancer Saudi patients.

Methods

Hundred formalin fixed paraffin embedded (FFPE) ovarian carcinoma tissues and their normal adjacent tissues (NAT) were included in the study. HPV was detected by nested polymerase chain reaction (PCR) using degenerated HPVL1 consensus primer pairs MY09/MY11 and GP5+/GP6 + to amplify a broad spectrum of HPV genotypes in a single reaction. The HPV positive samples were further genotyped using DNA sequencing. The physical state of the virus was identified using Amplification of Papillomavirus Oncogene Transcripts (APOT) assay in the samples positive for HPV16 and/or HPV18.

Results

High percentage of HPV (42%) was observed in ovarian carcinoma compared to 8% in the NAT. The high-risk HPV types 16, 18 and 45 were highly associated with the advanced stages of tumor, while low-risk types 6 and 11 were present in NAT. In malignant tissues, HPV-16 was the most predominant genotype followed by HPV-18 and -45. The percentage of viral integration into the host genome was significantly high (61.1%) compared to 38.9% episomal in HPV positive tumors tissues. In HPV18 genotype the percentage of viral integration was 54.5% compared to 45.5% episomal.

Conclusion

The high risk HPV genotypes in ovarian cancer may indicate its role in ovarian carcinogenesis. The HPV vaccination is highly recommended to reduce this type of cancer.

Human papillomavirus type-specific prevalence in the cervical cancer screening population of Czech women

Background

Infection with high-risk human papillomavirus (HPV)types has been recognized as a causal factor for the development of cervical cancer and a number of other malignancies. Today, vaccines against HPV, highly effective in the prevention of persistent infection and precancerous lesions, are available for the routine clinical practice.

Objectives

The data on the prevalence and type-specific HPV distribution in the population of each country are crucial for the surveillance of HPV type-specific prevalence at the onset of vaccination against HPV.

Methods

Women attending a preventive gynecological examination who had no history of abnormal cytological finding and/or surgery for cervical lesions were enrolled. All samples were tested for the presence of HPV by High-Risk Hybrid Capture 2 (HR HC2) and by a modified PCR-reverse line blot assay with broad spectrum primers (BS-RLB).

Results

Cervical smears of 1393 women were analyzed. In 6.5% of women, atypical cytological findings were detected. Altogether, 28.3% (394/1393) of women were positive for any HPV type by BS-RLB, 18.2% (254/1393) by HR HC2, and 22.3% (310/1393) by BS-RLB for HR HPV types. In women with atypical findings the prevalence for HR and any HPV types were significantly higher than in women with normal cytological findings. Overall, 36 different HPV types were detected, with HPV 16 being the most prevalent (4.8%). HPV positivity decreased with age; the highest prevalence was 31.5% in the age group 21-25 years.

Conclusions

Our study subjects represent the real screening population. HPV prevalence in this population in the Czech Republic is higher than in other countries of Eastern Europe. Also the spectrum of the most prevalent HPV types differs from those reported by others but HPV 16 is, concordantly, the most prevalent type. Country-specific HPV type-specific prevalences provide baseline information which will enable to measure the impact of HPV vaccination in the future.

Mapping of betapapillomavirus human papillomavirus 5 transcription and characterization of viral-genome replication function

Betapapillomavirus replication and transcription have not been studied in detail because of a lack of suitable cellular systems supporting human papillomavirus (HPV) genome replication. We have recently shown that the human osteosarcoma cell line U2OS provides a useful environment for the genome replication of many different HPVs, including the betapapillomaviruses HPV5 and HPV8. Using mutational analysis and complementation assay, we demonstrated herein that the viral early proteins E1 and E2 are viral transfactors that are necessary and sufficient for HPV5 genome replication. We also identified four HPV5 early promoter regions with transcription start sites (TSSs) at nucleotides (nt) 184/191, 460, 840, and 1254, respectively, and the HPV late promoter with a TSS at nt 7640. In addition, we mapped the HPV5 early polyadenylation cleavage sites via 3' rapid amplification of cDNA ends (3'RACE) to nt 4457 and 4475. In total, 14 different viral mRNA species, originating from the HPV5 genome, were mapped in U2OS cells during transient and stable replication. The main splicing donor and acceptor sites identified herein are consistent with the data previously obtained in HPV5-positive skin lesions. In addition, we identified novel E8 open reading frame (ORF)-containing transcripts (E8^E1C and E8^E2C) expressed from the HPV5 genome. Similar to several other papillomaviruses, the product of the E8^E2C mRNA acts as a repressor of viral genome replication.

Sp100 provides intrinsic immunity against human papillomavirus infection

Most DNA viruses associate with, and reorganize, nuclear domain 10 (ND10) bodies upon entry into the host nucleus. In this study, we examine the roles of the ND10 components PML, Sp100, and Daxx in the establishment of human papillomavirus type 18 (HPV18) infection of primary human keratinocytes. HPV18 DNA or HPV18 quasivirus was introduced into primary human keratinocytes depleted of each ND10 protein by small interfering RNA technology, and genome establishment was determined by using a quantitative immortalization assay and measurements of viral transcription and DNA replication. Keratinocyte depletion of Sp100 resulted in a substantial increase in the number of HPV18-immortalized colonies and a corresponding increase in viral transcription and DNA replication. However, Sp100 repressed viral transcription and replication only during the initial stages of viral establishment, suggesting that Sp100 acts as a repressor of incoming HPV DNA.

IMPORTANCE

The intrinsic immune system provides a first-line defense against invading pathogens. Host cells contain nuclear bodies (ND10) that are important for antiviral defense, yet many DNA viruses localize here upon cell entry. However, viruses also disrupt, reorganize, and modify individual components of the bodies. In this study, we show that one of the ND10 components, Sp100, limits the infection of human skin cells by human papillomavirus (HPV). HPVs are important pathogens that cause many types of infection of the cutaneous and mucosal epithelium and are the causative agents of several human cancers. Understanding how host cells counteract HPV infection could provide insight into antimicrobial therapies that could limit initial infection.

Role of innate immunity against human papillomavirus (HPV) infections and effect of adjuvants in promoting specific immune response

During the early stages of human papillomavirus (HPV) infections, the innate immune system creates a pro-inflammatory microenvironment by recruiting innate immune cells to eliminate the infected cells, initiating an effective acquired immune response. However, HPV exhibits a wide range of strategies for evading immune-surveillance, generating an anti-inflammatory microenvironment. The administration of new adjuvants, such as TLR (Toll-like receptors) agonists and alpha-galactosylceramide, has been demonstrated to reverse the anti-inflammatory microenvironment by down-regulating a number of adhesion molecules and chemo-attractants and activating keratinocytes, dendritic (DC), Langerhans (LC), natural killer (NK) or natural killer T (NKT) cells; thus, promoting a strong specific cytotoxic T cell response. Therefore, these adjuvants show promise for the treatment of HPV generated lesions and may be useful to elucidate the unknown roles of immune cells in the natural history of HPV infection. This review focuses on HPV immune evasion mechanisms and on the proposed response of the innate immune system, suggesting a role for the surrounding pro-inflammatory microenvironment and the NK and NKT cells in the clearance of HPV infections.

Conformational dissection of a viral intrinsically disordered domain involved in cellular transformation

Intrinsic disorder is abundant in viral genomes and provides conformational plasticity to its protein products. In order to gain insight into its structure-function relationships, we carried out a comprehensive analysis of structural propensities within the intrinsically disordered N-terminal domain from the human papillomavirus type-16 E7 oncoprotein (E7N). Two E7N segments located within the conserved CR1 and CR2 regions present transient α-helix structure. The helix in the CR1 region spans residues L8 to L13 and overlaps with the E2F mimic linear motif. The second helix, located within the highly acidic CR2 region, presents a pH-dependent structural transition. At neutral pH the helix spans residues P17 to N29, which include the retinoblastoma tumor suppressor LxCxE binding motif (residues 21-29), while the acidic CKII-PEST region spanning residues E33 to I38 populates polyproline type II (PII) structure. At pH 5.0, the CR2 helix propagates up to residue I38 at the expense of loss of PII due to charge neutralization of acidic residues. Using truncated forms of HPV-16 E7, we confirmed that pH-induced changes in α-helix content are governed by the intrinsically disordered E7N domain. Interestingly, while at both pH the region encompassing the LxCxE motif adopts α-helical structure, the isolated 21-29 fragment including this stretch is unable to populate an α-helix even at high TFE concentrations. Thus, the E7N domain can populate dynamic but discrete structural ensembles by sampling α-helix-coil-PII-ß-sheet structures. This high plasticity may modulate the exposure of linear binding motifs responsible for its multi-target binding properties, leading to interference with key cell signaling pathways and eventually to cellular transformation by the virus.

Substantial increase in the frequency of circulating CD4+NKG2D+ T cells in patients with cervical intraepithelial neoplasia grade 1

Background

The NKG2D receptor confers important activating signals to NK cells via ligands expressed during cellular stress and viral infection. This receptor has generated great interest because not only is it expressed on NK cells, but it is also seen in virtually all CD8⁺ cytotoxic T cells and is classically considered absent in CD4⁺ T cells. However, recent studies have identified a distinctive population of CD4⁺ T cells that do express NKG2D, which could represent a particular cytotoxic effector population involved in viral infections and chronic diseases. On the other hand, increased incidence of human papillomavirus-associated lesions in CD4⁺ T cell-immunocompromised individuals suggests that CD4⁺ T cells play a key role in controlling the viral infection. Therefore, this study was focused on identifying the frequency of NKG2D-expressing CD4⁺ T cells in patients with cervical intraepithelial neoplasia (CIN) 1. Additionally, factors influencing CD4⁺NKG2D⁺ T cell expansion were also measured.

Results

Close to 50% of patients with CIN 1 contained at least one of the 37 HPV types detected by our genotyping system. A tendency for increased CD4⁺ T cells and CD8⁺ T cells and decreased NK cells was found in CIN 1 patients. The percentage of circulating CD4⁺ T cells co-expressing the NKG2D receptor significantly increased in women with CIN 1 versus control group. Interestingly, the increase of CD4⁺NKG2D⁺ T cells was seen in patients with CIN 1, despite the overall levels of CD4⁺ T cells did not significantly increase. We also found a significant increase of soluble MICB in CIN 1 patients; however, no correlation with the presence of CD4⁺NKG2D⁺ T cells was seen. While TGF-beta was significantly decreased in the group of CIN 1 patients, both TNF-alpha and IL-15 showed a tendency to increase in this group.

Conclusions

Taken together, our results suggest that the significant increase within the CD4⁺NKG2D⁺ T cell population in CIN 1 patients might be the result of a chronic exposure to viral and/or pro-inflammatory factors, and concomitantly might also influence the clearance of CIN 1-type lesion.

Human papilloma virus lesions of the oral cavity: healing and relapse after treatment with 810-980 nm diode laser

This study evaluated the therapeutic efficacy of laser therapy in treating oral human papilloma virus (HPV) lesions. In particular, mode of action, healing, postoperative patient compliance, visual numeric scale (VNS) pain index, and recurrence were analyzed. During 2001-2012, in 170 patients (80 women and 90 men), 174 intraoral and lip HPV lesions were detected and excised by diode laser of different wavelengths (810-980 nm), with an average power of 2.1 W, in continuous wave mode, using 300 to 320 μm optical fibers. In most cases (95.4%), complete healing occurred in the first 30 days. There were no adverse effects and all patients were carefully followed up until complete healing occurred, documenting any complications. There was only one recurrence, which was later treated successfully; the mean VNS pain score was below one. In treating HPV lesions, the diode laser is not only a valuable tool for their eradication but especially it reduces relapses, thanks to the characteristics of the laser light.

HPV16 oncoproteins promote cervical cancer invasiveness by upregulating specific matrix metalloproteinases

Production of matrix metalloproteinases (MMPs) for degradation of extracellular matrix is a vital step in cancer metastasis. We investigated the effects of HPV16 oncoproteins (16E6, 16E6*I and 16E7), either individually or combined, on the transcription of 7 MMPs implicated in cervical cancer invasiveness. The levels of 7 MMPs reported to be increased in cervical cancer were determined in C33A stably expressing different HPV16 oncoproteins using quantitative RT-PCR and compared with invasion ability of cell lines using in vitro invasion and wound healing assays. Overexpression of MMP-2 and MT1-MMP was detected in HPV16E6E7 expressing cells which correlated with increased cell invasion. Combination of HPV oncoproteins always showed greater effects than its individual form. Inhibition of cell invasion using a specific MMP-2 inhibitor, OA-Hy, and anti-MT1-MMP antibody confirmed that invasion in these cells was dependent on both MMP-2 and MT1-MMP expression. Depletion of HPV16E6E7 by shRNA-mediated knock-down experiments resulted in decreased MMP-2 and MT1-MMP expression levels as well as reduced invasion ability which strongly suggested specific effects of HPV oncoproteins on both MMPs and on cell invasion. Immunohistochemistry study in invasive cervical cancers confirmed the enhanced in vivo expression of these two MMPs in HPV16-infected cells. In addition, possible sites required by HPV16E6E7 on the MMP-2 and MT1-MMP promoters were investigated and PEA3 (at -552/-540 for MMP-2, -303 for MT1-MMP) and Sp1 (at -91 for MMP-2, -102 for MT1-MMP) binding sites were shown to be essential for mediating their transactivation activity. In conclusion, our study demonstrated that HPV16E6 and E7 oncoproteins cooperate in promoting cervical cancer invasiveness by specifically upregulating MMP-2 and MT1-MMP transcription in a similar manner.

Expression and in Silico analysis of the recombinant bovine papillomavirus E6 protein as a model for viral oncoproteins studies

Bovine papillomaviruses (BPVs) are recognized as the causal agents of economical relevant diseases in cattle, associated with the development of tumors in skin and mucosa. The oncogenesis process is mainly associated with different viral oncoprotein expressions, which are involved in cell transformation. The expression and characterization of recombinant viral oncoproteins represent an attractive strategy to obtain biotechnological products as antibodies and potential vaccines, Thus, the aim of this work was to clone and express the BPV-1 and BPV-2 E6 recombinant proteins and perform in silico analysis in order to develop a strategy for the systematic study of other papillomaviruses oncoproteins. The results demonstrated that BPV-1 and BPV-2 E6 recombinant proteins were expressed and purified from bacterial system as well as its in silico analysis was performed in order to explore and predict biological characteristics of these proteins.

Prevalence and genetic variability in capsid L1 gene of rare human papillomaviruses (HPV) found in cervical lesions of women from North-East Brazil

The aim of this study was to examine the prevalence and genetic variability of the capsid L1 gene of rare HPV genotypes that were found in the cervical lesions of women from North-East Brazil. A total number of 263 patients were included in this study. HPV detection was performed using PCR followed by direct sequencing of MY09/11, as well as type-specific PCR to detect the Alpha-9 species. Epitope prediction was performed to determine whether or not the genetic variants are inserted in B-cell and T-cell epitopes. The prevalence of rare HPV types in cervical lesions was found to be 9.47%. The rare HPV genotypes that were detected were HPV-53, 54, 56, 61, 62, 66, 70, and 81. The genetic variability in the L1 gene of rare HPV types involved thirty nucleotide changes, eight of which were detected for the first time in this study. Moreover, some of these variants are embedded in B-cell or T-cell epitope regions. The results of this research suggest that rare HPV types might be involved in cervical lesions and some of these variants can be found in B-cell and T-cell epitopes. Data on the prevalence and variability of rare HPV types will assist in clarifying the role of these viruses in carcinogenesis.

The modulation of apoptosis by oncogenic viruses

Transforming viruses can change a normal cell into a cancer cell during their normal life cycle. Persistent infections with these viruses have been recognized to cause some types of cancer. These viruses have been implicated in the modulation of various biological processes, such as proliferation, differentiation and apoptosis. The study of infections caused by oncogenic viruses had helped in our understanding of several mechanisms that regulate cell growth, as well as the molecular alterations leading to cancer. Therefore, transforming viruses provide models of study that have enabled the advances in cancer research. Viruses with transforming abilities, include different members of the Human Papillomavirus (HPV) family, Hepatitis C virus (HCV), Human T-cell Leukemia virus (HTLV-1), Epstein Barr virus (EBV) and Kaposi’s Sarcoma Herpesvirus (KSHV).

Apoptosis, or programmed cell death, is a tightly regulated process that plays an important role in development and homeostasis. Additionally, it functions as an antiviral defense mechanism. The deregulation of apoptosis has been implicated in the etiology of diverse diseases, including cancer. Oncogenic viruses employ different mechanisms to inhibit the apoptotic process, allowing the propagation of infected and damaged cells. During this process, some viral proteins are able to evade the immune system, while others can directly interact with the caspases involved in apoptotic signaling. In some instances, viral proteins can also promote apoptosis, which may be necessary for an accurate regulation of the initial stages of infection.

Differential expression of HPV16 L2 gene in cervical cancers harboring episomal HPV16 genomes: influence of synonymous and non-coding region variations

We tested the hypothesis that (i) synonymous variations within the coding regions, and (ii) variations within the non-coding regions of HPV, influence cervical cancer (CaCx) pathogenesis under the impact of intact HPV16 genomes. Whole genome sequence analysis of HPV16 isolates within 70 CaCx cases and 25 non-malignant samples revealed that synonymous variations were significantly higher within the E6 (p = 0.014), E5 (p = 0.001) and L2 (p = 0.0002) genes of HPV16 isolates within cases, compared to isolates within non-malignant samples. All of the 25 (100%) humanized codons identified within L2 ORF of the samples analyzed, were harbored by CaCx cases, while 8 out of 25 (32%) were harbored by HPV16 positive non-malignant samples (p = 3.87105E-07). L2 (mRNA and protein) expression was evident only among cases with episomal viral genomes and L2 mRNA expression correlated significantly with E2 gene copy numbers suggesting expression from all episomal genomes. Among such cases, Asian American (AA) isolates portrayed all of the humanized codons (100%; 4–6/sample) recorded within L2, which was significantly higher (p = 2.02E-7) compared to the European (E) isolates (22.8%; none or 1–2/sample). Additionally, majority of E variant isolates within cases (54/57; 94.7%) portrayed a variation (T4228C) within the short non-coding region (NCR2) between E5 and L2 genes, which portrays a weak promoter activity specific for L2 mRNA expression. This resulted in loss of 9 out of 14 miRNA binding sites (hsa-miR-548 family), despite the significant overexpression of miR548a-5p and miR548d-5p among such cases (28.64 and 36.25 folds, respectively), in comparison to HPV negative control samples. The findings exemplify the biological relevance of sequence variations in HPV16 genomes and highlight that episomal HPV16 in CaCx cases employ multiple mechanisms to sustain L2 expression, thereby justifying the potential role of L2 in such cancers, as opposed to those harboring viral integration.

HPV16 synthetic long peptide (HPV16-SLP) vaccination therapy of patients with advanced or recurrent HPV16-induced gynecological carcinoma, a phase II trial

Background

Human papilloma virus type 16 (HPV16)-induced gynecological cancers, in particular cervical cancers, are found in many women worldwide. The HPV16 encoded oncoproteins E6 and E7 are tumor-specific targets for the adaptive immune system permitting the development of an HPV16-synthetic long peptide (SLP) vaccine with an excellent treatment profile in animal models. Here, we determined the toxicity, safety, immunogenicity and efficacy of the HPV16 SLP vaccine in patients with advanced or recurrent HPV16-induced gynecological carcinoma.

Methods

Patients with HPV16-positive advanced or recurrent gynecological carcinoma (n = 20) were subcutaneously vaccinated with an HPV16-SLP vaccine consisting of a mix of 13 HPV16 E6 and HPV16 E7 overlapping long peptides in Montanide ISA-51 adjuvant. The primary endpoints were safety, toxicity and tumor regression as determined by RECIST. In addition, the vaccine-induced T-cell response was assessed by proliferation and associated cytokine production as well as IFNγ-ELISPOT.

Results

No systemic toxicity beyond CTCAE grade II was observed. In a few patients transient flu-like symptoms were observed. In 9 out of 16 tested patients vaccine-induced HPV16-specific proliferative responses were detected which were associated with the production of IFNγ, TNFα, IL-5 and/or IL-10. ELISPOT analysis revealed a vaccine-induced immune response in 11 of the 13 tested patients. The capacity to respond to the vaccine was positively correlated to the patient’s immune status as reflected by their response to common recall antigens at the start of the trial. Median survival was 12.6 ± 9.1 months. No regression of tumors was observed among the 12 evaluable patients. Nineteen patients died of progressive disease.

Conclusions

The HPV16-SLP vaccine was well tolerated and induced a broad IFNγ-associated T-cell response in patients with advanced or recurrent HPV16-induced gynecological carcinoma but neither induced tumor regression nor prevented progressive disease. We, therefore, plan to use this vaccine in combination with chemotherapy and immunomodulation.

Monitoring human papillomavirus prevalence in urine samples: a review

Human papillomavirus (HPV) is the main cause of cervical cancer, and many countries now offer vaccination against HPV to girls by way of government-funded national immunization programs. Monitoring HPV prevalence in adolescents could offer a near-term biological measure of vaccine impact, and urine sampling may be an attractive large-scale method that could be used for this purpose. Our objective was to provide an overview of the literature on HPV DNA detection in urine samples, with an emphasis on adolescents. We searched the PubMed database using the terms “HPV” and “urine” and identified 21 female and 14 male study populations in which HPV prevalence in urine samples was reported, four of which included only asymptomatic female adolescents. We provide herein an overview of the recruitment setting, age, urine sampling procedure, lesion type, HPV assay, and HPV prevalence in urine samples and other urogenital samples for the studies included in this review. In female study populations, concordance for any HPV type and type-specific concordance in paired urine and cervical samples are provided in addition to sensitivity and specificity. We concluded that few studies on HPV prevalence in urine samples have been performed in asymptomatic female adolescent populations but that urine samples may be a useful alternative to cervical samples to monitor changes in HPV prevalence in females in the post-HPV vaccination era. However, care should be taken when extrapolating HPV findings from urine samples to the cervix. In males, urine samples do not seem to be optimal for monitoring HPV prevalence due to a low human genomic DNA content and HPV DNA detection rate compared to other urogenital sites. In each situation the costs and benefits of HPV DNA detection in urine compared to alternative monitoring options should be carefully considered.

Human papillomavirus infection is inhibited by host autophagy in primary human keratinocytes

Human papillomavirus (HPV) infection is severely limited in its natural host, primary human keratinocytes. Our data show HPV infectivity in primary keratinocytes is over 100- and 1,000-fold lower than in established keratinocyte cell lines NIKS and HaCaT, respectively. Here, we show that the basal level of autophagy in primary human foreskin keratinocytes (HFKs) is higher than in immortalized keratinocytes, and that HPV16 virions significantly induce autophagy in HFKs. Interestingly, HPV16 infectivity is dramatically enhanced by knockdown of essential autophagy genes as well as biochemical inhibition of autophagy. The increase in HPV16 infectivity by autophagy inhibition is most significant in HFKs, showing an inverse correlation with basal HPV16 infectivity in HFK, NIKS, HaCaT, and 293FT cells. Further, inhibition of autophagy delays degradation of HPV16 capsid proteins during virus trafficking, indicating that host autophagy induced by HPV16 virions inhibits infection of primary keratinocytes through rapid degradation of viral capsid proteins.

HIV Infection Alters the Spectrum of HPV Subtypes Found in Cervical Smears and Carcinomas from Kenyan Women

Infection with high risk HPV is implicated in pre-cancerous squamous intraepithelial lesions and their progression to cervical cancer. In the developed countries, infection with HPV 16 and 18 accounts for ~70% of cervical cancers, but it has been established that HPV type prevalence differs according to worldwide geographical location. In sub Saharan Africa infection with HPV is known to be augmented by HIV, which is endemic in this region. It is not yet clear, however, whether this ultimately influences progression to cervical cancer. Papillocheck^TM and multiplex PCR were used to determine the range of HPV genotypes found in cervical smears and carcinomas from HIV positive and negative Kenyan women. Smear samples from HIV-positive women had a higher prevalence of: multiple HPV infections; high-risk HPVs 52, 58, 68, potential high risk 53/70, low-risk 44/55 and abnormal cytology compared to HIV-negative women. A low overall prevalence (~8%) of types 16/18 was found in all smear samples tested (n = 224) although this increased in invasive cervical carcinoma tissues to ~80% for HIV-negative and ~46% for HIV-positive women. Furthermore, HPV45 was more common in cervical carcinoma tissues from HIV-positive women.

In summary HIV infection appears to alter the spectrum of HPV types found in both cervical smears and invasive cervical carcinomas. It is hypothesised there could be a complex interplay between these viruses which could either positively or negatively influence the rate of progression to cervical cancer.

Nucleotide variation in IL-10 and IL-12 and their receptors and cervical and vulvar cancer risk: a hybrid case-parent triad and case-control study

Given the important role of cell mediated immunity in viral clearance and control of premalignant lesions, we hypothesize that variation in the IL-12/IL-10 cytokine and cytokine receptor genes may influence cervical and vulvar cancer risk. We evaluated 76 tagSNPs from seven candidate genes (IL-10, IL-12A, IL-12B, IL-10RA, IL-10RB, IL-12RB1, and IL12RB2) in case-parent sets (n=43 cervical squamous cell carcinoma (SCC), n=96 cervical adenocarcinoma, n=53 vulvar SCC), additional cases (n=356 cervical SCC, n=406 cervical adenocarcinoma, and n=473 vulvar SCC) and population based controls (1,111). We calculated log-additive odds ratios (ORs) and 95% confidence intervals (CIs) for the association between tagSNP and cancer risk using a pseudo-likelihood based method which combined genotype information on cases, parents, and population controls. After correction for multiple comparisons, we identified several statistically significant SNP associations. Cervical SCC risk was associated with the minor alleles of the IL10RA rs9610 3' UTR SNP (OR=1.76, 95% CI=1.15-2.68) and two synonymous IL12RB2 SNPs (rs4297265, OR=0.46, 95% CI=0.26-0.82; rs2229546, OR=0.43, 95% CI=0.21-0.87). Cervical adenocarcinoma risk was associated with the minor alleles of the IL10RA rs4252314 intronic SNP (OR=2.23, 95% CI=1.26-3.96) and IL12RB1 rs11575934 non-synonymous SNP (OR=1.51, 95% CI=1.12-2.05). Finally, the minor allele of the IL12B rs3181224 3' UTR SNP was associated with a reduced risk of vulvar SCC (OR=0.30, 95% CI=0.12-0.74). These results raise the possibility that a shift in the balance of the immune response due to genetic variants in key cytokine genes could influence the development of cervical and vulvar cancer.

Genetic variability in L1 and L2 genes of HPV-16 and HPV-58 in Southwest China

HPV account for most of the incidence of cervical cancer. Approximately 90% of anal cancers and a smaller subset (<50%) of other cancers (oropharyngeal, penile, vaginal, vulvar) are also attributed to HPV. The L1 protein comprising HPV vaccine formulations elicits high-titre neutralizing antibodies and confers type restricted protection. The L2 protein is a promising candidate for a broadly protective HPV vaccine. In our previous study, we found the most prevalent high-risk HPV infectious serotypes were HPV-16 and HPV-58 among women of Southwest China. To explore gene polymorphisms and intratypic variations of HPV-16 and HPV-58 L1/L2 genes originating in Southwest China, HPV-16 (L1: n = 31, L2: n = 28) and HPV-58 (L1: n = 21, L2: n = 21) L1/L2 genes were sequenced and compared to others described and submitted to GenBank. Phylogenetic trees were then constructed by Neighbor-Joining and the Kimura 2-parameters methods (MEGA software), followed by an analysis of the diversity of secondary structure. Then selection pressures acting on the L1/L2 genes were estimated by PAML software. Twenty-nine single nucleotide changes were observed in HPV-16 L1 sequences with 16/29 non-synonymous mutations and 13/29 synonymous mutations (six in alpha helix and two in beta turns). Seventeen single nucleotide changes were observed in HPV-16 L2 sequences with 8/17 non-synonymous mutations (one in beta turn) and 9/17 synonymous mutations. Twenty-four single nucleotide changes were observed in HPV-58 L1 sequences with 10/24 non-synonymous mutations and 14/24 synonymous mutations (eight in alpha helix and four in beta turn). Seven single nucleotide changes were observed in HPV-58 L2 sequences with 4/7 non-synonymous mutations and 3/7 synonymous mutations. The result of selective pressure analysis showed that most of these mutations were of positive selection. This study may help understand the intrinsic geographical relatedness and biological differences of HPV-16/HPV-58 and contributes further to research on their infectivity, pathogenicity, and vaccine strategy.

Chlamydia induces anchorage independence in 3T3 cells and detrimental cytological defects in an infection model

Chlamydia are gram negative, obligate intracellular bacterial organisms with different species causing a multitude of infections in both humans and animals. Chlamydia trachomatis is the causative agent of the sexually transmitted infection (STI) Chlamydia, the most commonly acquired bacterial STI in the United States. Chlamydial infections have also been epidemiologically linked to cervical cancer in women co-infected with the human papillomavirus (HPV). We have previously shown chlamydial infection results in centrosome amplification and multipolar spindle formation leading to chromosomal instability. Many studies indicate that centrosome abnormalities, spindle defects, and chromosome segregation errors can lead to cell transformation. We hypothesize that the presence of these defects within infected dividing cells identifies a possible mechanism for Chlamydia as a cofactor in cervical cancer formation. Here we demonstrate that infection with Chlamydia trachomatis is able to transform 3T3 cells in soft agar resulting in anchorage independence and increased colony formation. Additionally, we show for the first time Chlamydia infects actively replicating cells in vivo. Infection of mice with Chlamydia results in significantly increased cell proliferation within the cervix, and in evidence of cervical dysplasia. Confocal examination of these infected tissues also revealed elements of chlamydial induced chromosome instability. These results contribute to a growing body of data implicating a role for Chlamydia in cervical cancer development and suggest a possible molecular mechanism for this effect.

Human papillomavirus infections and cancer stem cells of tumors from the uterine cervix

Different rate of development of productive infections (as low grade cervical intraepithelial neoplasias), or high grade lesions and cervical malignant tumors associated with infections of the Transformation zone (TZ) by High-Risk Human Papillomavirus (HR-HPV), could suggest that different epithelial host target cells could exist. If there is more than one target cell, their differential infection by HR-HPV may play a central role in the development of cervical cancer. Recently, the concept that cancer might arise from a rare population of cells with stem cell-like properties has received support in several solid tumors, including cervical cancer (CC). According to the cancer stem cell (CSC) hypothesis, CC can now be considered a disease in which stem cells of the TZ are converted to cervical cancer stem cells by the interplay between HR-HPV viral oncogenes and cellular alterations that are thought to be finally responsible for tumor initiation and maintenance. Current studies of CSC could provide novel insights regarding tumor initiation and progression, their relation with viral proteins and interplay with the tumor micro-environment. This review will focus on the biology of cervical cancer stem cells, which might contribute to our understanding of the mechanisms responsible for cervical tumor development.

Sonoporation delivery of monoclonal antibodies against human papillomavirus 16 E6 restores p53 expression in transformed cervical keratinocytes

High-risk types of human papillomavirus (HPV), such as HPV16, have been found in nearly all cases of cervical cancer. Therapies targeted at blocking the HPV16 E6 protein and its deleterious effects on the tumour suppressor pathways of the cell can reverse the malignant phenotype of affected keratinocytes while sparing uninfected cells. Through a strong interdisciplinary collaboration between engineering and biology, a novel, non-invasive intracellular delivery method for the HPV16 E6 antibody, F127-6G6, was developed. The method employs high intensity focused ultrasound (HIFU) in combination with microbubbles, in a process known as sonoporation. In this proof of principle study, it was first demonstrated that sonoporation antibody delivery into the HPV16 positive cervical carcinoma derived cell lines CaSki and SiHa was possible, using chemical transfection as a baseline for comparison. Delivery of the E6 antibody using sonoporation significantly restored p53 expression in these cells, indicating the antibody is able to enter the cells and remains active. This delivery method is targeted, non-cytotoxic, and non-invasive, making it more easily translatable for in vivo experiments than other transfection methods.

Different regions of the HPV-E7 and Ad-E1A viral oncoproteins bind competitively but through distinct mechanisms to the CH1 transactivation domain of p300

p300 is a transcriptional coactivator that participates in many important processes in the cell, including proliferation, differentiation, and apoptosis. The viral oncoproteins, adenovirus (Ad) E1A and human papillomavirus (HPV) E7, have been implicated in binding to p300. The Ad-E1A-p300 interaction has been shown to result in the induction of cellular proliferation, epigenetic reprogramming, and cellular transformation and cancer. The HPV-E7-p300 interaction, on the other hand, is not well understood. p300 contains three zinc-binding domains, CH1-CH3, and studies have shown that Ad-E1A can bind to the p300 CH1 and CH3 domains whereas E7 can bind to the CH1 domain and to a lesser extent to the CH2 and CH3 domains. Here we address how high-risk HPV16-E7 and Ad5-E1A, which have different structures, can both bind the p300 CH1 domain. Using pull-down, gel filtration, and analytical ultracentrifugation studies, we show that the N-terminus and CR1 domains of Ad5-E1A and the CR1 and CR2 domains of HPV16-E7 bind to the p300 CH1 domain competitively and with midnanomolar and low micromolar dissociation constants, respectively. We also show that Ad5-E1A can form a ternary complex with the p300 CH1 domain and the retinoblastoma pRb transcriptional repressor, whereas HPV16-E7 cannot. These studies suggest that the HPV16-E7 and Ad5-E1A viral oncoproteins bind to the same p300 CH1 domain to disrupt p300 function by distinct mechanisms.

Mechanisms of virus immune evasion lead to development from chronic inflammation to cancer formation associated with human papillomavirus infection

Human papillomavirus (HPV) has developed strategies to escape eradication by innate and adaptive immunity. Immune response evasion has been considered an important aspect of HPV persistence, which is the main contributing factor leading to HPV-related cancers. HPV-induced cancers expressing viral oncogenes E6 and E7 are potentially recognized by the immune system. The major histocompatibility complex (MHC) class I molecules are patrolled by natural killer cells and CD8+ cytotoxic T lymphocytes, respectively. This system of recognition is a main target for the strategies of immune evasion deployed by viruses. The viral immune evasion proteins constitute useful tools to block defined stages of the MHC class I presentation pathway, and in this way HPV avoids the host immune response. The long latency period from initial infection to persistence signifies that HPV evolves mechanisms to escape the immune response. It has now been established that there are oncogenic mechanisms by which E7 binds to and degrades tumor suppressor Rb, while E6 binds to and inactivates tumor suppressor p53. Therefore, interaction of p53 and pRb proteins can give rise to an increased immortalization and genomic instability. Overexpression of NF-κB in cervical and penile cancers suggests that NF-κB activation is a key modulator in driving chronic inflammation to cancer. HPV oncogene-mediated suppression of NF-κB activity contributes to HPV escape from the immune system. This review focuses on the diverse mechanisms of the virus immune evasion with HPV that leads to chronic inflammation and cancer.

Differential gene expression between skin and cervix induced by the E7 oncoprotein in a transgenic mouse model

HPV16 E7 oncoprotein expression in K14E7 transgenic mice induces cervical cancer after 6 months of treatment with the co-carcinogen 17β-estradiol. In untreated mice, E7 also induces skin tumors late in life albeit at low penetrance. These findings indicate that E7 alters cellular functions in cervix and skin so as to predispose these organs to tumorigenesis. Using microarrays, we determined the global genes expression profile in cervical and skin tissue of young adult K14E7 transgenic mice without estrogen treatment. In these tissues, the E7 oncoprotein altered the transcriptional pattern of genes involved in several biological processes including signal transduction, transport, metabolic process, cell adhesion, apoptosis, cell differentiation, immune response and inflammatory response. Among the E7-dysregulated genes were ones not previously known to be involved in cervical neoplasia including DMBT1, GLI1 and 17βHSD2 in cervix, as well as MMP2, 12, 14, 19 and 27 in skin.

Contribution of retinoblastoma LOH and the p53 Arg/Pro polymorphism to cervical cancer

Epidemiological studies indicate that infections by certain types of human papillomaviruses (HPVs) are causally linked to the development of cervical cancer. It is also known that HPV infections alone do not cause progression to cervical cancer, as additional genetic changes such as loss of distinct chromosomal regions, inactivation of tumor-suppressor genes and activation of oncogenes must also occur in order for malignant transformation to take place. In the present study, 78 patients diagnosed with cervical cancer and 36 cervical cancer-free cases (control) were analyzed for high-risk HPV genotypes (16 and 18) by polymerase chain reaction (PCR). Loss of heterozygosity (LOH) of the retinoblastoma gene (Rb) at two polymorphic intronic sites (intron 1 and 17) and the p53 polymorphism in codon 72 were detected by RFLP and allele-specific PCR, respectively. HPV 16 and 18 were found at frequencies of 93.6 and 8.3% in the cervical cancer and control samples, respectively. LOH was detected in 63% of patients in intron 1 and/or intron 17. p53 allele frequency for Arg/Arg was 43.6% (34/78), for Arg/Pro 37.2% (29/78) and for Pro/Pro 19.2% (15/78). The relative risk (RR) of LOH and Arg/Arg alone was 1.7 and 1.1, respectively, while the combined RR for Rb LOH and p53 Arg/Arg was 2.5. The present study showed a significant association of the chromosomal allelic loss of Rb in Sudanese cervical cancer patients, while no such association was observed with other parameters, such as clinical stage and degree of differentiation; hence, it cannot be a determinant of tumor behavior in cervical carcinoma. Although the p53 arginine allele is itself an important risk factor for cervical cancer, the combined risk with LOH of Rb, which appears to be greater, might indicate a possible epistatic effect of the two genes/polymorphisms.

Inactivating all three rb family pocket proteins is insufficient to initiate cervical cancer

Human papillomavirus-16 (HPV-16) is associated etiologically with many human cervical cancers. It encodes 3 oncogenes E5, E6, and E7. Of these oncogenes, E7 has been found to be the dominant driver of cervical cancer in mice. More than 100 cellular proteins have been reported to associate with HPV-16 E7, which is thought to dysregulate the cell cycle in part by binding and inducing the degradation of pRb and its related pocket protein family members, p107 and p130. The ability of E7 to inactivate the pRb family correlates with its ability to induce head and neck cancers in mice. We previously showed that the inactivation of pRb is itself not sufficient to recapitulate the oncogenic properties of E7 in cervical carcinogenesis. In this study, we evaluated mice that were deficient in multiple pocket proteins, including mice that lacked pRb, p107, and p130. Strikingly, combined loss of two or all 3 pocket proteins resulted in development of high-grade cervical intraepithelial neoplasia, but not frank cervical carcinoma. These findings strongly argue that the oncogenic properties of HPV-16 E7 in human cervical carcinogenesis may involve disruption of E7 binding proteins beyond simply the pRb family members.

High-resolution melting molecular signatures for rapid identification of human papillomavirus genotypes

Background

Genotyping of human papillomarvirus (HPV) is crucial for patient management in a clinical setting. This study accesses the combined use of broad-range real-time PCR and high-resolution melting (HRM) analysis for rapid identification of HPV genotypes.

Methods

Genomic DNA sequences of 8 high-risk genotypes (HPV16/18/39/45/52/56/58/68) were subject to bioinformatic analysis to select for appropriate PCR amplicon. Asymmetric broad-range real-time PCR in the presence of HRM dye and two unlabeled probes specific to HPV16 and 18 was employed to generate HRM molecular signatures for HPV genotyping. The method was validated via assessment of 119 clinical HPV isolates.

Results

A DNA fragment within the L1 region was selected as the PCR amplicon ranging from 215–221 bp for different HPV genotypes. Each genotype displayed a distinct HRM molecular signature with minimal inter-assay variability. According to the HRM molecular signatures, HPV genotypes can be determined with one PCR within 3 h from the time of viral DNA isolation. In the validation assay, a 91% accuracy rate was achieved when the genotypes were in the database. Concomitantly, the HRM molecular signatures for additional 6 low-risk genotypes were established.

Conclusions

This assay provides a novel approach for HPV genotyping in a rapid and cost-effective manner.

Prevalence of human papillomavirus infection in a Kashmiri ethnic female population

Human papillomavirus (HPV) infection is estimated to be the most common sexually transmitted infection and is one of the causal factors in cervical cancer. Understanding the epidemiology of this infection is an important step toward developing strategies for its prevention. Cervical samples from 210 healthy women with normal and abnormal cytomorphology were studied for the detection of HPV DNA by polymerase chain reaction (PCR), utilizing the two most commonly used consensus primer sets. The primers; MY09/MY11 and GP5+/GP6+ located within the L1 region of HPV genome, amplified a broad spectrum of HPV genotypes in a single reaction. The PCR amplification of HPV genomes is a sensitive method that is used for the detection of cervicovaginal HPV. With the aim of identifying the HPV types, samples were also subjected to PCR using specific primers for HPV types 16 and 18. In addition, basic demographic information, sociodemographic characteristics, and sexual behavior were recorded. HPV was detected in 13.8% of the study population aged 18 to 57 years using PCR. HPV16 (6.6%) was more commonly detected than HPV18 (3.8%). The highest prevalence of HPV infection was seen in women below 27 years old, and then, a new increase was seen higher than the age of 48. In conclusion, our study demonstrated that younger age at marriage, economic status, parity, and dwelling are the major risk factors determining HPV infection.

Generation of organotypic raft cultures from primary human keratinocytes

The development of organotypic epithelial raft cultures has provided researchers with an efficient in vitro system that faithfully recapitulates epithelial differentiation. There are many uses for this system. For instance, the ability to grow three-dimensional organotypic raft cultures of keratinocytes has been an important milestone in the study of human papillomavirus (HPV)(1). The life cycle of HPV is tightly linked to the differentiation of squamous epithelium(2). Organotypic epithelial raft cultures as demonstrated here reproduce the entire papillomavirus life cycle, including virus production(3,4,5). In addition, these raft cultures exhibit dysplastic lesions similar to those observed upon in vivo infection with HPV. Hence this system can also be used to study epithelial cell cancers, as well as the effect of drugs on epithelial cell differentiation in general. Originally developed by Asselineau and Prunieras(6) and modified by Kopan et al.(7), the organotypic epithelial raft culture system has matured into a general, relatively easy culture model, which involves the growth of cells on collagen plugs maintained at an air-liquid interface (Figure 1A). Over the course of 10-14 days, the cells stratify and differentiate, forming a full thickness epithelium that produces differentiation-specific cytokeratins. Harvested rafts can be examined histologically, as well as by standard molecular and biochemical techniques. In this article, we describe a method for the generation of raft cultures from primary human keratinocytes. The same technique can be used with established epithelial cell lines, and can easily be adapted for use with epithelial tissue from normal or diseased biopsies(8). Many viruses target either the cutaneous or mucosal epithelium as part of their replicative life cycle. Over the past several years, the feasibility of using organotypic raft cultures as a method of studying virus-host cell interactions has been shown for several herpesviruses, as well as adenoviruses, parvoviruses, and poxviruses(9). Organotypic raft cultures can thus be adapted to examine viral pathogenesis, and are the only means to test novel antiviral agents for those viruses that are not cultivable in permanent cell lines.

Effects of human papillomavirus (HPV) type 16 oncoproteins on the expression of involucrin in human keratinocytes

BACKGROUND

The human papillomavirus (HPV) life cycle is closely linked to keratinocyte differentiation. Oncogenic HPV infection has been shown to hamper the normal differentiation of keratinocytes; however, the underlying mechanisms responsible for this phenomenon are yet to be clarified. Here, we aimed to study the effects of HPV16 E6 and E7 oncogenes on the expression of involucrin (IVL), an established marker of keratinocyte differentiation, in human foreskin keratinocyte (HFK) cells.

RESULTS

The differentiation of HFK cells by serum and high calcium significantly increased both the mRNA and the protein levels of IVL. The E6 and E7 oncoproteins of HPV16 together caused strong down-regulation of IVL mRNA and protein both in proliferating and in differentiating HFK cells. To study the effects of HPV oncogenes on the IVL promoter, we made transient transfection assays and luciferase tests and found that HPV 16 E6 but not E7 repressed IVL promoter activity in proliferating HFK cells. The inhibitory effect of HPV 16 E6 on the human IVL promoter could be localised to the proximal regulatory region (PRR) of the gene.

CONCLUSIONS

These results suggest that the down-regulation of IVL promoter activity by HPV 16 E6 significantly contribute to the inhibition of endogenous IVL expression by the HPV 16 oncoproteins. In contrast, the down-regulation of endogenous IVL expression by HPV16 E7 is probably not caused by a direct and specific effect of E7 on the IVL promoter.