Molecular mechanisms of human papillomavirus-induced carcinogenesis

Human Papillomavirus and Associated Cancers: A Review

The human papillomavirus is the most common sexually transmitted infection in the world. Most HPV infections clear spontaneously within 2 years of infection; however, persistent infection can result in a wide array of diseases, ranging from genital warts to cancer. Most cases of cervical, anal, and oropharyngeal cancers are due to HPV infection, with cervical cancer being one of the leading causes of cancer death in women worldwide. Screening is available for HPV and cervical cancer, but is not available everywhere, particularly in lower-resource settings. HPV infection disproportionally affects individuals living with HIV, resulting in decreased clearance, increased development of cancer, and increased mortality. The development of the HPV vaccine has shown a drastic decrease in HPV-related diseases. The vaccine prevents cervical cancer with near 100% efficacy, if given prior to first sexual activity. Vaccination uptake remains low worldwide due to a lack of access and limited knowledge of HPV. Increasing awareness of HPV and access to vaccination are necessary to decrease cancer and HPV-related morbidity and mortality worldwide.

Navigating therapeutic strategies: HPV classification in head and neck cancer

The World Health Organisation recognised human papillomavirus (HPV) as the cause of multiple cancers, including head and neck cancers. HPV is a double-stranded DNA virus, and its viral gene expression can be controlled after infection by cellular and viral promoters. In cancer cells, the HPV genome is detected as either integrated into the host genome, episomal (extrachromosomal), or a mixture of integrated and episomal. Viral integration requires the breakage of both viral and host DNA, and the integration rate correlates with the level of DNA damage. Interestingly, patients with HPV-positive head and neck cancers generally have a good prognosis except for a group of patients with fully integrated HPV who show worst clinical outcomes. Those patients present with lowered expression of viral genes and limited infiltration of cytotoxic T cells. An impediment to effective therapy applications in the clinic is the sole testing for HPV positivity without considering the HPV integration status. This review will discuss HPV integration as a potential determinant of response to therapies in head and neck cancers and highlight to the field a novel therapeutic avenue that would reduce the cancer burden and improve patient survival.

Molecular pathways in the development of HPV-induced oropharyngeal cancer

Oropharyngeal cancer, a subset of head and neck cancer, is increasingly recognized as a unique clinical entity primarily influenced by high-risk human papillomavirus (HPV) infections, particularly HPV-16. This review delves into the viral life cycle of HPV-16 and its interactions with host cells, with a specific focus on the crucial roles played by the viral oncoproteins E6 and E7. These oncoproteins drive cellular proliferation by targeting critical tumor suppressor proteins like p53 and Rb, resulting in uncontrolled cell growth and genomic instability. Furthermore, the significance of epigenetic modifications induced by HPV-16 and their implications is important for cancer progression. This comprehensive review provides valuable insights into the intricate molecular landscape of HPV-induced oropharyngeal cancer, shedding light on the development of targeted therapies and preventive strategies for this emerging global health concern. Video Abstract.

The cervical microbiota of Hispanics living in Puerto Rico is nonoptimal regardless of HPV status

The cervicovaginal microbiota is influenced by host physiology, immunology, lifestyle, and ethnicity. We hypothesized that there would be differences in the cervicovaginal microbiota among pregnant, nonpregnant, and menopausal women living in Puerto Rico (PR) with and without human papillomavirus (HPV) infection and cervical cancer. We specifically wanted to determine if the microbiota is associated with variations in cervical cytology. A total of 294 women, including reproductive-age nonpregnant (N = 196), pregnant (N = 37), and menopausal (N = 61) women, were enrolled. The cervicovaginal bacteria were characterized by 16S rRNA amplicon sequencing, the HPV was genotyped with SPF10-LiPA, and cervical cytology was quantified. High-risk HPV (HR-HPV, 67.3%) was prevalent, including genotypes not covered by the 9vt HPV vaccine. Cervical lesions (34%) were also common. The cervical microbiota was dominated by Lactobacillus iners. Pregnant women in the second and third trimesters exhibited a decrease in diversity and abundance of microbes associated with bacterial vaginosis. Women in menopause had greater alpha diversity, a greater proportion of facultative and strictly anaerobic bacteria, and higher cervicovaginal pH than premenopausal women. Cervical lesions were associated with greater alpha diversity. However, no significant associations between the microbiota and HPV infection (HR or LR-HPV types) were found. The cervicovaginal microbiota of women living in Puerto Rican were either dominated by L. iners or diverse microbial communities regardless of a woman's physiological stage. We postulate that the microbiota and the high prevalence of HR-HPV increase the risk of cervical lesions among women living in PR. IMPORTANCE In the enclosed manuscript, we provide the first in-depth characterization of the cervicovaginal microbiota of Hispanic women living in Puerto Rico (PR), using a 16S rRNA approach, and include women of different physiological stages. Surprisingly we found that high-risk HPV was ubiquitous with a prevalence of 67.3%, including types not covered by the 9vt HPV vaccine. We also found highly diverse microbial communities across women groups-with a reduction in pregnant women, but dominated by nonoptimal Lactobacillus iners. Additionally, we found vaginosis-associated bacteria as Dialister spp., Gardnerella spp., Clostridium, or Prevotella among most women. We believe this is a relevant and timely article expanding knowledge on the cervicovaginal microbiome of PR women, where we postulate that these highly diverse communities are conducive to cervical disease.

Concatenation of molecular docking and dynamics simulation of human papillomavirus type 16 E7 oncoprotein targeted ligands: In quest of cervical cancer's treatment

The Human papillomaviruses type 16 E7 oncoprotein is a 98-amino-acid, 11-kilodalton acidic oncoprotein with three conserved portions. Due to its interaction with the pRb-E2F complex, CKII, CKI (mostly p21), and even HDAC1, it possesses strong transformative and carcinogenic qualities that inhibit normal differentiation and cell cycle regulation. Here, we target the E7 oncoprotein using two prior research active compounds: asarinin and thiazolo[3,2-a]benzimidazole-3(2H)-one,2-(2-fluorobenzylideno)-7,8-dimethyl (thiazolo), and valproic acid as a control. We are performing molecular docking followed by molecular dynamic analysis. By acting as competitive inhibitors in the binding site, it was hypothesized that both drugs would inhibit E7-mediated pRb degradation and E7-mediated p21 degradation, resulting in decreased cell cycle progression, immortalization, and proliferation. In addition, we expect that the direct inhibitory action of valproic acid in E7 will target the CKII-mediated phosphorylation pathway necessary for destabilizing p130 and pRb. According to the results of the dynamic simulation, stable interactions exist between every compound. Despite the instability of E7 protein, stability results indicate that both natural chemicals are preferable, with thiazolo outperforming valproic acid.

The Structural Profile of HPV 18 in Terms of Chromosomal and Nuclear Degenerative Changes and the Ratio of Nucleus/Cytoplasm on Liquid based Cervical Cells

Background

HPV 18 is one of the important oncogenic types. HPV 18 is generally evaluated together with HPV 16 and/or high-risk HPV types in light microscopic studies. The purpose of this study was to evaluate the impact of only HPV 18 on the nucleus/cytoplasm ratio, and chromosomal and nuclear degenerative changes in liquid-based samples.

Materials and Methods

Eighty liquid-based cervical samples were used in this retrospective study. These smears were prepared by HPV Deoxyribonucleic Acid (DNA) detection and genotyping with the Cobas 4800 HPV system. Forty HPV 18 infected and forty smears with no infection agent were evaluated for chromosomal (nuclear budding, micronuclei), nuclear degenerative changes (membrane irregularity, nuclear enlargement, hyperchromasia, abnormal chromatin distribution, binucleation (BN), karyorrhexis (KR), karyolysis (KL), karyopyknosis (KP)), and cytologic findings (koilocyte (KC), cells with perinuclear PR) using light microscopy. Cellular diameters were evaluated using image analysis software. Statistical analysis was performed with Statistical Package for Social Sciences (SPSS) 19.0. p values < .05 were considered significant.

Results

The statistically significant difference between the presence of HPV 18 and karyorrectic cell, KC, nuclear membrane irregularity, enlargement, the mean nuclear width and height (p < 0.05). No cellular changes other than those mentioned were observed.

Conclusions

The present study is significant in that, it reveals the relationship between only and particularly HPV 18 and nucleus/cytoplasm ratio, and chromosomal and nuclear degenerative changes in liquid-based cytology. HPV 18 affects KR, koilocytosis, nuclear membrane irregularity, enlargement, and nuclear diameters. Light microscopic analysis of these abnormalities increases the sensitivity and specificity of cytology in the evaluation of cellular pictures due to HPV 18.

Willingness to get HPV vaccination among female university students in Kuwait and its relation to vaccine conspiracy beliefs

A substantial burden of high-risk human papillomavirus (HPV) infections and HPV-related cancers can be mitigated by vaccination. The current study aimed to investigate the willingness of female students at the University of Kuwait to get HPV vaccination and its possible association with general vaccine conspiracy beliefs (VCBs). This cross-sectional survey study was conducted during September-November 2022 using a validated VCB scale as the survey instrument. The final sample comprised 611 respondents with a median age of 22 y and a majority of Arab ethnicity (n = 600, 98.2%). Only 360 respondents (56.9%) heard of HPV before participation and these students showed an above-average level of HPV knowledge (mean knowledge score of 12.7 ± 2.6 out of 16 as the maximum score), of whom only 33 self-reported HPV vaccine uptake (9.2%). The willingness to accept free-of-charge HPV vaccination was seen among 69.8% of the participants, with 20.1% who were hesitant and 10.1% who were resistant. The acceptance of HPV vaccination if payment is required was 23.1%. Reasons for HPV vaccine hesitancy/resistance included complacency to the HPV disease risks, lack of confidence in HPV vaccination, and inconvenience. The embrace of VCBs was associated with significantly higher odds of HPV vaccine hesitancy/resistance. The current study showed the detrimental impact of endorsing vaccine conspiracy beliefs manifested in lower intention to get HPV vaccination among female university students in Kuwait. This should be considered in vaccine promotion efforts aiming to reduce the burden of HPV cancers.

The association of cervicovaginal Langerhans cells with clearance of human papillomavirus

Human papillomavirus (HPV) clearance is important in eliminating cervical cancer which contributes to high morbidity and mortality in women. Nevertheless, it remains largely unknown about key players in clearing pre-existing HPV infections. HPV antigens can be detected by the most important cervical antigen-presenting cells (Langerhans cells, LCs), of which the activities can be affected by cervicovaginal microbiota. In this review, we first introduce persistent HPV infections and then describe HPV-suppressed LCs activities, including but not limited to antigen uptake and presentation. Given specific transcriptional profiling of LCs in cervical epithelium, we also discuss the impact of cervicovaginal microbiota on LCs activation as well as the promise of exploring key microbial players in activating LCs and HPV-specific cellular immunity.

The HPV Induced Cancer Resource (THInCR): a Suite of Tools for Investigating HPV-Dependent Human Carcinogenesis

Human papillomaviruses (HPVs) are highly infectious and cause the most common sexually transmitted viral infections. They induce hyperproliferation of squamous epithelial tissue, often forming warts. Virally encoded proteins reprogram gene expression and cell growth to create an optimal environment for viral replication. In addition to their normal roles in infection, functional alterations induced by viral proteins establish conditions that frequently contribute to human carcinogenesis. In fact, ~5% of human cancers are caused by HPVs, with virtually all cervical squamous cell carcinomas (CESC) and an increasing number of head and neck squamous cell carcinomas (HNSC) attributed to HPV infection. The Cancer Genome Atlas (TCGA) molecularly characterized thousands of primary human cancer samples in many cancer types, including CESC and HNSC, and created a comprehensive atlas of genomic, epigenomic, and transcriptomic data. This publicly available genome-wide information provides an unprecedented opportunity to expand the knowledge of the role that HPV plays in human carcinogenesis. While many tools exist to mine these data, few, if any, focus on the comparison of HPV-positive cancers with their HPV-negative counterparts or adjacent normal control tissue. We have constructed a suite of web-based tools, The HPV Induced Cancer Resource (THInCR), to utilize TCGA data for research related to HPV-induced CESC and HNSC. These tools allow investigators to gain greater biological and medical insights by exploring the impacts of HPV on cellular gene expression (mRNA and microRNA), altered gene methylation, and associations with patient survival and immune landscape features. These tools are accessible at https://thincr.ca/. IMPORTANCE The suite of analytical tools of THInCR provides the opportunity to investigate the roles that candidate target genes identified in cell lines or other model systems contribute to in actual HPV-dependent human cancers and is based on large-scale TCGA data sets. Expression of target genes, including both mRNA and microRNA, can be correlated with HPV gene expression, epigenetic changes in DNA methylation, patient survival, and numerous immune features, like leukocyte infiltration, interferon gamma response, T cell response, etc. Data from these analyses may immediately provide evidence to validate in vitro observations, reveal insights into mechanisms of virus-mediated alterations in cell growth, behavior, gene expression, and innate and adaptive immunity and may help hypothesis generation for further investigations.

The Involvement of Human Papilloma Virus in Gastrointestinal Cancers

Human Papilloma Virus (HPV) is one of the most common sexually transmitted infections worldwide. HPV infection has a strong relationship with the onset of cervix uteri, vagina, penis, anus, and oropharynx, but also tonsils and tongue cancers. Some epidemiological data indicate that except for gynecologic cancers, HPV infection can be one of the risk factors associated with a greater risk of induction and progression of gastrointestinal cancers. Data, however, remain contradictory and definite conclusions cannot be drawn, so far. The following review aims to organize recent evidence and summarize the current state of knowledge regarding the association between HPV infection and gastrointestinal tumors primarily focusing on esophageal, liver, gastric, colorectal, and anal cancers.

The Roles of the Virome in Cancer

Viral infections as well as changes in the composition of the intestinal microbiota and virome have been linked to cancer. Moreover, the success of cancer immunotherapy with checkpoint inhibitors has been correlated with the intestinal microbial composition of patients. The transfer of feces-which contain mainly bacteria and their viruses (phages)-from immunotherapy responders to non-responders, known as fecal microbiota transplantation (FMT), has been shown to be able to convert some non-responders to responders. Since phages may also increase the response to immunotherapy, for example by inducing T cells cross-reacting with cancer antigens, modulating phage populations may provide a new avenue to improve immunotherapy responsiveness. In this review, we summarize the current knowledge on the human virome and its links to cancer, and discuss the potential utility of bacteriophages in increasing the responder rate for cancer immunotherapy.

HPV and Recurrent Respiratory Papillomatosis: A Brief Review

Recurrent Respiratory Papillomatosis (RRP) is a rare but severe manifestation of human papillomavirus (HPV). As our knowledge about HPV infections has expanded, it has become possible to understand the course of RRP disease and unravel plausible efficient methods to manage the disease. However, the surge in reports on HPV has not been accompanied by a similar increase in research about RRP specifically. In this paper, we review the clinical manifestation and typical presentation of the illness. In addition, the pathogenesis and progression of the disease are described. On the other hand, we discuss the types of treatments currently available and future treatment strategies. The role of vaccination in both the prevention and treatment of RRP will also be reviewed. We believe this review is essential to update the general knowledge on RRP with the latest information available to date to enhance our understanding of RRP and its management.

The Role of Human Papilloma Virus in Dictating Outcomes in Head and Neck Squamous Cell Carcinoma

The Human Papilloma Virus (HPV) is an oncogenic virus which is associated with the development of head and neck squamous cell carcinoma (HNSCC), predominantly within the oropharynx. Approximately 25% of oropharyngeal squamous cell carcinoma (OPSCC) cases worldwide are attributable to HPV infection, with an estimated 65% in the United States. Transmission is via exposure during sexual contact, with distinctive anatomical features of the tonsils providing this organ with a predilection for infection by HPV. No premalignant lesion is identifiable on clinical examination, thus no comparative histological features to denote the stages of carcinogenesis for HPV driven HNSCC are identifiable. This is in contrast to HPV-driven cervical carcinoma, making screening a challenge for the head and neck region. However, HPV proffers a favorable prognosis in the head and neck region, with better overall survival rates in contrast to its HPV negative counterparts. This has resulted in extensive research into de-intensifying therapies aiming to minimize the morbidity induced by standard concurrent chemo-radiotherapy without compromising efficacy. Despite the favorable prognosis, cases of recurrence and/or metastasis of HPV positive HNSCC do occur, and are linked with poor outcomes. HPV 16 is the most frequent genotype identified in HNSCC, yet there is limited research to date studying the impact of other HPV genotype with respect to overall survival. A similar situation pertains to genetic aberrations associated in those with HPV positive HNSCC who recur, with only four published studies to date. Somatic mutations in TSC2, BRIP1, NBN, TACC3, NFE2l2, STK11, HRAS, PIK3R1, TP63, and FAT1 have been identified in recurrent HPV positive OPSCC. Finding alternative therapeutic strategies for this young cohort may depend on upfront identification of HPV genotypes and mutations which are linked with worse outcomes, thus ensuring appropriate stratification of treatment regimens.

Success Rate of Benign Oral Squamous Papilloma Treatments After Different Surgical Protocols (Conventional, Nd:YAG, CO2 and Diode 980 nm Lasers): A 34-Year Retrospective Study

Objective: The aim of our retrospective study is to compare the long-term recurrence rate of the benign oral squamous papilloma (OSP) with different laser-assisted treatments and conventional procedures (use of scalpels) aiming to suggest the most suitable surgical protocol showing the lowest recurrence rate. Background: A retrospective multicenter DATA collection between 1985 and 2019 covering 781 OSP cases concerning different surgical protocols used for the treatment of OSP was done and included the use of different laser wavelengths [neodymium-doped yttrium-aluminum-garnet (Nd:YAG), carbon dioxide (CO₂), and Diode 980 nm] and the conventional surgeries using the scalpel. The age, sex, and the oral location of the OSP were noted. Methods: Three different surgical protocols were selected in our study: protocol 1 regrouped surgical procedures performing the excision of OSP with an in-depth safety margin of 1 mm and just at the base of the tumor with reduced excision of the grossly normal marginal mucosa around the tumor (0-1 mm). Protocol 2 and 3 were similar to protocol 1, but with an additional excision of 1-2 mm and ≥3 mm of the grossly normal marginal mucosa, respectively, for group 2 and 3. All laser-treated OSP wounds were left without sutures. In the conventionally treated OSP, sutures were regularly performed. Follow-up was done after 15 days and at 1, 6, and 18 months. The three included wavelengths were Nd:YAG (1064 nm), CO₂ laser (10,600 nm), and diode laser (980 nm). Results: After 18 months of follow-up, the highest success rate was obtained with protocol 3 (100% with Nd:YAG, 99% with CO₂, 98.4% with diode, and 99% with the scalpel), which was significantly higher than the values of protocol 2 (96.6% with Nd:YAG, 91% with CO₂, 96% with diode, and 95% with the scalpel) and the protocol 1 (38% with Nd:YAG, 29% with CO₂, 33% with diode, and 30% with the scalpel). The oral locations of OSP were 30% on palates, 30% on the tongue, 16% on cheek, 14% on lips, and 10% on other locations. Conclusions: The lowest recurrence rate was observed when a minimum of three millimeters (≥3 mm) of grossly normal aspect mucosa around the OSP was included in the excisions. The laser wavelengths and the use of scalpel did not show any significant difference in terms of recurrence.

Combination Therapies for HPV-Associated Malignancies

Human papillomavirus (HPV)-associated malignancies cause almost all cases of cervical cancer in women, and a significant percentage of head and neck cancer, together totaling almost 5% of the global cancer burden, and representing an important public health issue. The approval and use of two prophylactic HPV vaccines, Gardasil® and Cervarix®, have significantly decreased infections with HPV, but unfortunately, prophylactic vaccination does not treat established infections or malignancies resulting from HPV. Therefore, therapies for HPV-associated malignancies are necessary to improve the quality of life and survival in patients with these diseases. This review will detail new combinations of therapies in clinical development for HPV-associated malignancies.

Inhibitory role of oleanolic acid and esculetin in HeLa cells involve multiple signaling pathways

The global burden of cervical cancer from low and middle-income groups is increasing at alarming rates with more than half a million women being diagnosed every year. Although the disease is largely preventable when screened and diagnosed in earlier stages, the development of resistance and relapse had resulted in a poor prognosis. Therefore, a comprehensive approach needs to be put forward to understand and develop new preventive and therapeutic strategies to effectively combat cancer. Recently, much attention has been diverted to plant-derivatives for the treatment as they exhibit potent anti-cancer properties and side-effects caused by chemotherapeutic agents can also be prevented. Oleanolic acid and Esculetin are natural compounds known for their anti-cancer properties. Hence, the present study investigates the effect and mechanism of these compounds on cervical carcinoma, using HeLa cells. Posttreatment, it was observed that these compounds inhibited proliferation by both arresting the cells in the sub G1 phase and inducing senescence. Also, a marked reduction in the migration and cell survival was observed, as evidenced by results obtained from wound healing assay and Annexin V-FITC/PI staining. Furthermore, studies on the expression pattern of genes involved in major signaling pathways demonstrated a profound effect of these compounds. Taken together, the results of our study suggest that both Oleanolic acid and esculetin serve as a plausible therapeutic agent.

Human Papillomavirus Selected Properties and Related Cervical Cancer Prevention Issues

High-risk human papillomavirus strains are widely known to be the causative agents responsible for cervical cancer development. Aggregated damage caused by papillomaviruses solely is estimated in at least 5% of all malignancies of the human body and 16% in cancers that affect the female genital area. Enhanced understanding of the complex issue on how the high extent of carcinogenicity is eventually formed due to the infection by the Papoviridae family would contribute to enhancing current prevention strategies not only towards cervical cancer, but also other HPV associated cancers. This review article is aimed at presenting the key points in two directions: the current cervical cancer prevention and related aspects of HPV behavior. Virtually all applied technologies related to HPV diagnostics and screening programs, such as HPV tests, colposcopy-based tests (VIA/VILI), conventional and liquid-based cytology, currently available are presented. Issues of availability, advantages, and drawbacks of the screening programs, as well as vaccination strategies, are also reviewed in the article based on the analyzed sources. The current point of view regarding HPV is discussed with emphasis on the most problematic aspect of the HPV family concerning the observed increasing number of highly carcinogenic types. Present trends in HPV infection diagnostics throughout the human fluids and tissues are also reported, including the latest novelties in this field, such as HPV assay/self-sample device combinations. Besides, a brief outline of the related prevention issues in Kazakhstan, the leading country of Central Asia, is presented. Kazakhstan, as one of the post-soviet middle-income countries, may serve as an example of the current situation in those terrains, concerning the implementation of globally accepted cervical cancer prevention strategies. Along with positive achievements, such as the development of a nationwide screening program, a range of drawbacks is also analyzed and discussed.

Naturally Occurring Sclareol Diterpene Augments the Chemosensitivity of Human Hela Cervical Cancer Cells by Inducing Mitochondrial Mediated Programmed Cell Death, S-Phase Cell Cycle Arrest and Targeting Mitogen-Activated Protein Kinase (MAPK)/Extracellular-Signal-Regulated Kinase (ERK) Signaling Pathway

Background

Cervical cancer is a major threat to female health worldwide. This study was performed to study the anticancer potential of sclareol and as a chemo-sensitizing agent against human cervical cancer cells along with evaluating its effects on apoptosis, cell cycle arrest, and MAPK/ERK signaling pathway.

Material/Methods

MTT assay was performed to check cell viability, morphological changes were observed through phase-contrast microscopy, DAPI (4′,6-diamidino-2-phenylindole) staining and TUNEL (terminal deoxynucleotidyl transferase dUTP nick end labelling) assays were performed to evaluate apoptotic effects; MMP (matrix metalloproteinase) and cell cycle analysis were examined through flow cytometry. Western blotting analysis was performed to check the protein expressions of MAPK/ERK signaling pathway and apoptosis proteins.

Results

Results depicted that both sclareol and cisplatin induced cytotoxic effects individually but when used in combination, it led to much more pronounced cytotoxic effects indicating a synergistic effect of sclareol on cisplatin. Sclareol treatment led to significant decrease in the levels of p-MEK and p-ERK. Significant morphological changes (including chromatin condensation, nuclear fragmentation) in cervical cancer cells were seen after treatment. Western blot showed significant alterations including increase in BAX and decrease in BCL-2 levels. An increase in the S-phase cells, indicating cell cycle arrest at S-phase was seen along with modulating the expressions of CDK-1and Cdc25C, and increase in the levels of p-CDK-1, cyclin-B1, cyclin-A, and p-Cdc25C.

Conclusions

Sclareol not only induced cytotoxic effects but also enhanced chemosensitivity of human cervical cancer cells towards cisplatin and these effects are mediated via MAPK/ERK signaling pathway, stimulation of apoptosis and S-phase cell cycle arrest.

Therapeutic Vaccines for HPV-Associated Malignancies

Human papillomavirus (HPV)-related malignancies are responsible for almost all cases of cervical cancer in women, and over 50% of all cases of head and neck carcinoma. Worldwide, HPV-positive malignancies account for 4.5% of the global cancer burden, or over 600,000 cases per year. HPV infection is a pressing public health issue, as more than 80% of all individuals have been exposed to HPV by age 50, representing an important target for vaccine development to reduce the incidence of cancer and the economic cost of HPV-related health issues. The approval of Gardasil^® as a prophylactic vaccine for high-risk HPV 16 and 18 and low-risk HPV6 and 11 for people aged 11-26 in 2006, and of Cervarix^® in 2009, revolutionized the field and has since reduced HPV infection in young populations. Unfortunately, prophylactic vaccination does not induce immunity in those with established HPV infections or HPV-induced neoplasms, and there are currently no therapeutic HPV vaccines approved by the US Food and Drug Administration. This comprehensive review will detail the progress made in the development of therapeutic vaccines against high-risk HPV types, and potential combinations with other immunotherapeutic agents for more efficient and rational designs of combination treatments for HPV-associated malignancies.

Gold-Hybridized Zinc Oxide Nanorods as Real-Time Low-Cost NanoBiosensors for Detection of virulent DNA signature of HPV-16 in Cervical Carcinoma

Detection of host integrated viral oncogenes are critical for early and point-of-care molecular diagnostics of virus-induced carcinoma. However, available diagnostic approaches are incapable of combining both cost-efficient medical diagnosis and high analytical performances. To circumvent this, we have developed an improved IDE-based nanobiosensor for biorecognition of HPV-16 infected cervical cancer cells through electrochemical impedance spectroscopy. The system is fabricated by coating gold (Au) doped zinc oxide (ZnO) nanorods interfaced with HPV-16 viral DNA bioreceptors on top of the Interdigitated Electrode (IDE) chips surface. Due to the concurrently improved sensitivity and biocompatibility of the designed nanohybrid film, Au decorated ZnO-Nanorod biosensors demonstrate exceptional detection of HPV-16 E6 oncogene, the cancer biomarker for HPV infected cervical cancers. This sensor displayed high levels of sensitivity by detecting as low as 1fM of viral E6 gene target. The sensor also exhibited a stable functional life span of more than 5 weeks, good reproducibility and high discriminatory properties against HPV-16. Sensor current responses are obtained from cultured cervical cancer cells which are close to clinical cancer samples. Hence, the developed sensor is an adaptable tool with high potential for clinical diagnosis especially useful for economically challenged countries/regions.

Human Papillomavirus Infection and Cervical Cancer: Epidemiology, Screening, and Vaccination-Review of Current Perspectives

Viral infections contribute as a cause of 15–20% of all human cancers. Infection by oncogenic viruses can promote different stages of carcinogenesis. Among many types of HPV, around 15 are linked to cancer. In spite of effective screening methods, cervical cancer continues to be a major public health problem. There are wide differences in cervical cancer incidence and mortality by geographic region. In addition, the age-specific HPV prevalence varies widely across different populations and showed two peaks of HPV positivity in younger and older women. There have been many studies worldwide on the epidemiology of HPV infection and oncogenic properties due to different HPV genotypes. However, there are still many countries where the population-based prevalence has not yet been identified. Moreover, cervical cancer screening strategies are different between countries. Organized cervical screening programs are potentially more effective than opportunistic screening programs. Nevertheless, screening programs have consistently been associated with a reduction in cervical cancer incidence and mortality. Developed countries have achieved such reduced incidence and mortality from cervical cancer over the past 40 years. This is largely due to the implementation of organized cytological screening and vaccination programs. HPV vaccines are very effective at preventing infection and diseases related to the vaccine-specific genotypes in women with no evidence of past or current HPV infection. In spite of the successful implementation of the HPV vaccination program in many countries all over the world, problems related to HPV prevention and treatment of the related diseases will continue to persist in developing and underdeveloped countries.

Myosin-X is essential to the intercellular spread of HIV-1 Nef through tunneling nanotubes

Tunneling nanotubes (TNTs) are intercellular structures that allow for the passage of vesicles, organelles, genomic material, pathogenic proteins and pathogens. The unconventional actin molecular motor protein Myosin-X (Myo10) is a known inducer of TNTs in neuronal cells, yet its role in other cell types has not been examined. The Nef HIV-1 accessory protein is critical for HIV-1 pathogenesis and can self-disseminate in culture via TNTs. Understanding its intercellular spreading mechanism could reveal ways to control its damaging effects during HIV-1 infection. Our goal in this study was to characterize the intercellular transport mechanism of Nef from macrophages to T cells. We demonstrate that Nef increases TNTs in a Myo10-dependent manner in macrophages and observed the transfer of Nef via TNTs from macrophages to T cells. To quantify this transfer mechanism, we established an indirect flow cytometry assay. Since Nef expression in T cells down-regulates the surface receptor CD4, we correlated the decrease in CD4 to the transfer of Nef between these cells. Thus, we co-cultured macrophages expressing varying levels of Nef with a T cell line expressing high levels of CD4 and quantified the changes in CD4 surface expression resulting from Nef transfer. We demonstrate that Nef transfer occurs via a cell-to-cell dependent mechanism that directly correlates with the presence of Myo10-dependent TNTs. Thus, we show that Nef can regulate Myo10 expression, thereby inducing TNT formation, resulting in its own transfer from macrophages to T cells. In addition, we demonstrate that up-regulation of Myo10 induced by Nef also occurs in human monocyte derived macrophages during HIV-1 infection.

Patterns and mechanisms of structural variations in human cancer

Next-generation sequencing technology has enabled the comprehensive detection of genomic alterations in human somatic cells, including point mutations, chromosomal rearrangements, and structural variations (SVs). Using sophisticated bioinformatics algorithms, unbiased catalogs of SVs are emerging from thousands of human cancer genomes for the first time. Via careful examination of SV breakpoints at single-nucleotide resolution as well as local DNA copy number changes, diverse patterns of genomic rearrangements are being revealed. These "SV signatures" provide deep insight into the mutational processes that have shaped genome changes in human somatic cells. This review summarizes the characteristics of recently identified complex SVs, including chromothripsis, chromoplexy, microhomology-mediated breakage-induced replication (MMBIR), and others, to provide a holistic snapshot of the current knowledge on genomic rearrangements in somatic cells.

Paediatric Virology and its interaction between basic science and clinical practice (Review)

The 3rd Workshop on Paediatric Virology, which took place on October 7th, 2017 in Athens, Greece, highlighted the role of breast feeding in the prevention of viral infections during the first years of life. Moreover, it focused on the long-term outcomes of respiratory syncytial virus and rhinovirus infections in prematurely born infants and emphasised the necessity for the development of relevant preventative strategies. Other topics that were covered included the vaccination policy in relation to the migration crisis, mother‑to‑child transmission of hepatitis B and C viruses, vaccination against human papilloma viruses in boys and advances on intranasal live‑attenuated vaccination against influenza. Emphasis was also given to the role of probiotics in the management of viral infections in childhood, the potential association between viral infections and the pathogenesis of asthma, fetal and neonatal brain imaging and the paediatric intensive care of children with central nervous system viral infections. Moreover, an interesting overview of the viral causes of perinatal mortality in ancient Greece was given, where recent archaeological findings from the Athenian Agora's bone well were presented. Finally, different continuing medical educational options in Paediatric Virology were analysed and evaluated. The present review provides an update of the key topics discussed during the workshop.

Induction of apoptosis by pinostrobin in human cervical cancer cells: Possible mechanism of action

Pinostrobin (PN) is a naturally occurring dietary bioflavonoid, found in various medicinal herbs/plants. Though anti-cancer potential of many such similar constituents has been demonstrated, critical biochemical targets and exact mechanism for their apoptosis-inducing actions have not been fully elucidated. The present study was aimed to investigate if PN induced apoptosis in cervical cancer cells (HeLa) of human origin. It is demonstrated that PN at increasing dose effectivity reduced the cell viability as well as GSH and NO2- levels. Condensed nuclei with fragmented chromatin and changes in mitochondrial matrix morphology clearly indicated the role of mitochondria in PN induced apoptosis. A marked reduction in mitochondrial membrane potential and increased ROS production after PN treatment showed involvement of free radicals, which in turn further augment ROS levels. PN treatment resulted in DNA damage, which could have been triggered by an increase in ROS levels. Decrease in apoptotic cells in the presence of caspase 3 inhibitor in PN-treated cells suggested that PN induced apoptosis via caspase dependent pathways. Additionally, a significant increase in the expression of proteins of extrinsic (TRAIL R1/DR4, TRAIL R2/DR5, TNF RI/TNFRSF1A, FADD, Fas/TNFRSF6) and intrinsic pathway (Bad, Bax, HTRA2/Omi, SMAC/Diablo, cytochrome C, Pro-Caspase-3, Cleaved Caspase-3) was observed in the cells exposed to PN. Taken together, these observations suggest that PN efficiently induces apoptosis through ROS mediated extrinsic and intrinsic dependent signaling pathways, as well as ROS mediated mitochondrial damage in HeLa cells.

DNA Vaccine Encoding HPV16 Oncogenes E6 and E7 Induces Potent Cell-mediated and Humoral Immunity Which Protects in Tumor Challenge and Drives E7-expressing Skin Graft Rejection

We have previously shown that a novel DNA vaccine technology of codon optimization and the addition of ubiquitin sequences enhanced immunogenicity of a herpes simplex virus 2 polynucleotide vaccine in mice, and induced cell-mediated immunity when administered in humans at relatively low doses of naked DNA. We here show that a new polynucleotide vaccine using the same technology and encoding a fusion protein of the E6 and E7 oncogenes of high-risk human papillomavirus type 16 (HPV16) is immunogenic in mice. This vaccine induces long-lasting humoral and cell-mediated immunity and protects mice from establishment of HPV16-E7-expressing tumors. In addition, it suppresses growth of readily established tumors and shows enhanced efficacy when combined with immune checkpoint blockade targeted at PD-L1. This vaccine also facilitates rejection of HPV16-E7-expressing skin grafts that demonstrate epidermal hyperplasia with characteristics of cervical and vulvar intraepithelial neoplasia. Clinical studies evaluating the efficacy of this vaccine in patients with HPV16 premalignancies are planned.

Cytology and high risk HPV testing in cervical cancer screening program: Outcome of 3-year follow-up in an academic institute

BACKGROUND

Combination of cervical cytology and high-risk human papillomavirus (HR-HPV) testing, co-testing, has been increasingly used in screening cervical cancers. The present study summarized the outcome of co-testing by reviewing 3-year clinical and pathological follow-up information.

METHODS

Patients were retrospectively identified via computerized search and were grouped based on the cytologic diagnosis and HR-HPV status as negative for intraepithelial lesion or malignancy (NILM)/HPV-, NILM/HPV+, atypical squamous cells of undetermined significance (ASC-US)/HPV-, ASC-US/HPV+, low grade squamous intraepithelial lesion (LSIL)/HPV-, LSIL/HPV+, atypical squamous cells, cannot exclude high grade squamous intraepithelial lesion (ASC-H)/HPV-, ASC-H/HPV+, high grade squamous intraepithelial lesion (HSIL)/HPV-, and HSIL/HPV+. The patients' pertinent past medical history and follow-up information were analyzed.

RESULTS

During 3-year follow-up period, histologically proven HSIL was found in 5 of 1565 (0.3%) patients with NILM/HPV-, 7 of 141 (5.0%) with NILM/HPV+, 2 of 502 (0.4%) with ASC-US/HPV-, 30 of 274 (10.9%) with ASC-US/HPV+, 1 of 81 (1.2%) with LSIL/HPV-, 28 of 159 (17.6%) with LSIL/HPV+, 3 of 18 (16.7%) with ASC-H/HPV-, 34 of 69 (49.3%) with ASC-H/HPV+, 7 of 7 (100%) with HSIL/HPV-, and 35 of 56 (62.5%) HSIL/HPV+. In reviewing 12 HSIL cases that were originally diagnosed as NILM, 7 remained as NILM, and the other 5 were reclassified as 1 HSIL, 1 ASC-H, and 3 ASC-US, respectively. In 18 HSIL cases with negative HR-HPV, 12 patients had a prior history of positive HR-HPV testing and/or positive p16 IHC stain in the follow-up cervical biopsy.

CONCLUSION

HR-HPV testing plays an important role in cervical cancer screening by identifying HSIL in patients with ASC-US, LSIL, and NILM. Co-testing is an optimal method to identifying the patients with higher risk for developing cervical abnormalities.

The presence of aberrant p53 pattern is a negative prognostic predictor in squamous cell carcinoma of the nasal vestibule

The aim of this study was to analyze the role of Ki-67, p53, and the "aberrant p53 pattern" in squamous cell carcinomas of the nasal vestibule. Patients between 1995 and 2014 were included. Baseline characteristics and outcome were analyzed with respect to immunohistochemical staining of Ki-67 and p53. "Aberrant p53 pattern" was represented by a moderate or strong staining of at least 60% of the tumor cells or a complete absence of immunoreactivity. Forty-six patients were included of whom 31 (67.4%) were available for Ki-67 and 32 (69.9%) for p53 immunohistochemistry. The "aberrant pattern" of p53 was present in 50% of the patients. While immunoreactivity for both Ki-67 and p53 was not related to each other or outcome, the "aberrant p53 pattern" was associated with a worse disease-free survival (p = 0.014). The "aberrant p53 pattern" is a negative prognostic factor in squamous cell carcinoma of the nasal vestibule and might enable a patient-tailored treatment.

Role of Human Papillomavirus in Vulvar Cancer

Human papillomavirus (HPV) is involved in one of the at least 2 pathways leading to vulvar squamous cell carcinoma (VSCC). Inactivation of p53 and retinoblastoma by the viral products E6 and E7 is involved in malignant transformation. The percentage of HPV-positive VSCCs ranges from 18% to 75%, depending on the geographical area. HPV-associated tumors affect relatively young women and arise from high-grade intraepithelial lesions, identical to other HPV-associated premalignant lesions of the anogenital tract. HPV-independent tumors tend to affect older women and usually arise in a background of inflammatory skin disorders and a subtle variant of in situ lesion called differentiated vulvar intraepithelial neoplasia. HPV-positive tumors tend to be of basaloid or warty types, whereas HPV-independent tumors tend to be of keratinizing type, but there is frequent overlap between histologic types. There is no conclusive evidence yet on the best strategy in terms of determining HPV attribution. HPV DNA detection is generally considered the gold standard although there is some concern about misclassification when using this technique alone. p16 immunostaining has shown to be an excellent surrogate marker of HPV infection. Positive results for both techniques are considered the best evidence for HPV-association. The prognostic role of HPV in VSCC is still contradictory, but increasing evidence suggests that HPV-associated tumors are less aggressive. Currently, there are no differences in treatment between HPV-associated and HPV-independent VSCC, but novel immunological strategies based on anti-HPV antigens are being evaluated in clinical trials.

Detection of cervical intraepithelial neoplasia with HPVE6/E7 mRNA among women with atypical squamous cells of unknown significance

OBJECTIVE

To compare E6/E7 mRNA and HPV DNA assays for evaluating women with atypical cells of undetermined significance (ASCUS).

METHODS

The present prospective study enrolled patients with ASCUS undergoing HPV testing at Third Affiliated Hospital of Zhengzhou University, China, between September 1, 2013, and January 31, 2016. Patients with positive HPV DNA test results underwent screening by E6/E7 mRNA assay, and the accuracy of HPV DNA and E6/E7 mRNA testing were compared, with histology used for definitive diagnoses.

RESULTS

In total, 591 patients with ASCUS underwent HPV DNA screening, with 455 and 136 having positive and negative results, respectively; 252 patients with positive results and 66 with negative results underwent biopsy and histology testing and were included in the study. The sensitivity of the E6/E7 mRNA assay was similar to that of HPV DNA testing (88.2%, 95% confidence interval [CI] 77.6-94.4 vs 90.7%, 95%CI 81.2-95.9; P=0.636) for the detection of cervical intraepithelial neoplasia grade 2+, and the specificity was higher (36.4%, 95%CI 29.6-43.9 vs 24.3%, 95%CI 19.1-30.3; P=0.006). The area under the receiver operating characteristic curve was greater for E6/E7 mRNA testing compared with HPV DNA testing (0.658 vs 0.588).

CONCLUSION

The higher specificity of the E6/E7 mRNA assay means it could be a promising technique in the management of women with ASCUS.

Complete genome sequence of Deltapapillomavirus 4 (bovine papillomavirus 2) from a bovine papillomavirus lesion in Amazon Region, Brazil

The complete genome sequence of bovine papillomavirus 2 (BPV2) from Brazilian Amazon Region was determined using multiple-primed rolling circle amplification followed by Illumina sequencing. The genome is 7,947 bp long, with 45.9% GC content. It encodes seven early (E1, E2,E4, E5, E6,E7, and E8) and two late (L1 and L2) genes. The complete genome of a BPV2 can help in future studies since this BPV type is highly reported worldwide although the lack of complete genome sequences available.

Genome characterization of a bovine papillomavirus type 5 from cattle in the Amazon region, Brazil

Papillomaviruses are small and complex viruses with circular DNA genome that belongs to the Papillomavirus family, which comprises at least 39 genera. The bovine papillomavirus (BPV) causes an infectious disease that is characterized by chronic and proliferative benign tumors that affect cattle worldwide. In the present work, the full genome sequence of BPV type 5, an Epsilonpapillomavirus, is reported. The genome was recovered from papillomatous lesions excised from cattle raised in the Amazon region, Northern Brazil. The genome comprises 7836 base pairs and exhibits the archetypal organization of the Papillomaviridae. This is of significance for the study of BPV biology, since currently available full BPV genome sequences are scarce. The availability of genomic information of BPVs can provide better understanding of the differences in genetics and biology of papillomaviruses.

Novel Bovine Papillomavirus Type Discovered by Rolling-Circle Amplification Coupled with Next-Generation Sequencing

Currently, fifteen bovine papillomavirus (BPV) types have been identified and classified into four genera: Deltapapillomavirus, Epsilonpapillomavirus, Dyoxipapillomavirus, and Xipapillomavirus. Here, the complete genome sequence of a new BPV type (BPV 04AC14) recovered from a papillomatous lesion is reported. The genome is 7,282 bp in length and exhibits the classic genetic organization and motifs of the members of Papillomaviridae. Maximum likelihood phylogenetic analyses revealed that BPV 04AC14 clusters with members of the Xipapillomavirus genus. The nucleotide sequence of the L1 capsid protein of the novel BPV is closely related to its counterpart, BPV3, with which it shares 79% similarity. These findings suggest that this virus is a new BPV type of the Xipapillomavirus genus.

DNA Damage Reduces the Quality, but Not the Quantity of Human Papillomavirus 16 E1 and E2 DNA Replication

Human papillomaviruses (HPVs) are causative agents in almost all cervical carcinomas. HPVs are also causative agents in head and neck cancer, the cases of which are increasing rapidly. Viral replication activates the DNA damage response (DDR) pathway; associated proteins are recruited to replication foci, and this pathway may serve to allow for viral genome amplification. Likewise, HPV genome double-strand breaks (DSBs) could be produced during replication and could lead to linearization and viral integration. Many studies have shown that viral integration into the host genome results in unregulated expression of the viral oncogenes, E6 and E7, promoting HPV-induced carcinogenesis. Previously, we have demonstrated that DNA-damaging agents, such as etoposide, or knocking down viral replication partner proteins, such as topoisomerase II β binding protein I (TopBP1), does not reduce the level of DNA replication. Here, we investigated whether these treatments alter the quality of DNA replication by HPV16 E1 and E2. We confirm that knockdown of TopBP1 or treatment with etoposide does not reduce total levels of E1/E2-mediated DNA replication; however, the quality of replication is significantly reduced. The results demonstrate that E1 and E2 continue to replicate under genomically-stressed conditions and that this replication is mutagenic. This mutagenesis would promote the formation of substrates for integration of the viral genome into that of the host, a hallmark of cervical cancer.

Relationships between p53 mutation, HPV status and outcome in oropharyngeal squamous cell carcinoma

BACKGROUND AND PURPOSE

This study aimed to examine the rate and type of p53 mutation in oropharyngeal cancer (OSCC). Relationships were sought between human papillomavirus (HPV) status and p53 mutation. The role of p53 mutation as a prognostic factor independent of HPV status and as a modifier of the effect of HPV on outcomes was also examined.

METHODS

The HPV status of 202 cases was determined by HPV DNA by RT-PCR and p16 immunohistochemistry. P53 mutation in exon 5-8 was determined by pyrosequencing. Findings were correlated with known clinicopathological factors and outcomes.

RESULTS

48% of the cases were HPV positive and they were significantly less likely to have a p53 mutation than HPV-negative OSCCs (25.8% vs 46.7%, p=0.0021). Mutation was most common in exon 5. Among patients with HPV-positive OSCC, there was no significant difference in p53 mutation by smoking status (22.2% for never smokers and 30.8% for current or ex-smokers). Patients with p53 mutant OSCC had significantly worse overall survival (p=0.01). There was no statistical evidence that p53 mutation modified the effect of HPV status on outcomes. In the multivariate analysis, positive HPV status remained the strongest predictor of outcomes. p53 mutation status was not a significant predictor of outcome after adjusting for age, gender, T stage, N stage and HPV status.

CONCLUSIONS

In summary, HPV-positive OSCC are less likely to have mutant p53 than HPV-negative OSCC. Our study did not show any evidence that p53 mutation could modify the effect of HPV status on outcomes.

Association of CCND1 gene polymorphism with cervical cancer susceptibility in Caucasian population: a meta-analysis

OBJECTIVE

To study G870A polymorphism in CCND1 gene and the risk of cervical cancer susceptibility in Caucasian population by meta-analysis.

METHODS

Search the correlative study of G870A polymorphism in CCND1 gene and cervical cancer susceptibility in PubMed and EMBASE database, and extract the reference data according to the including criteria. We used RevMan 5.2 software to merge the OR value and 95% confidence interval and to perform meta-analysis.

RESULTS

Five case-control studies were enrolled into the analysis, including 1665 patients with cervical cancer and 2511 healthy people as control. It was revealed by meta-analysis that, in the Caucasian population, there was no significant correlation between G870A polymorphism in CCND1 gene and the risk of cervical cancer (G allele vs. A: OR = 1.01, 95% CI = 0.80-1.27, P = 0.95; AA vs. GA + GG: OR = 1.13, 95% CI = 0.98-1.30, P = 0.10; (GA + AA) vs. GG: OR = 1.15, 95% CI = 0.72-1.85, P = 0.55).

CONCLUSION

G870A polymorphism in CCND1 gene may be uncorrelated with the development of cervical cancer in Caucasian population.

Chronic inflammation in urothelial bladder cancer

The association between inflammation and cancer has been pointed out in epidemiological and clinical studies, revealing how chronic inflammation may contribute to carcinogenesis in various malignancies. However, the molecular events leading to malignant transformation in a chronically inflamed environment are not fully understood. In urothelial carcinoma of the urinary bladder, inflammation plays a dual role. On the one hand, chronic inflammation is a well-established risk factor for the development of bladder cancer (BC), as seen in Schistosoma haematobium infection. On the other, intravesical therapy by bacillus Calmette-Guérin (BCG), which induces inflammation, offers protection against cancer recurrence. The large variety of pro-inflammatory mediators expressed by BC and immune cells binds to specific receptors which control signalling pathways. These activate transcription of a plethora of downstream factors. This review summarizes recent data regarding inflammation and urothelial carcinoma, with special emphasis on the role the inflammatory response plays in BC recurrence risk and progression.

Up-Regulation of miR-21 Is Associated with Cervicitis and Human Papillomavirus Infection in Cervical Tissues

MicroRNA-21 (miR-21) is recognized as an oncomir and shows up-regulation in many types of human malignancy. The aim of this study was to investigate the association of miR-21 expression associated with HPV infection in normal and abnormal cervical tissues. Cervical tissue samples with different cytological or histopathological grades were investigated for HPV by PCR and for miR-21 and programmed cell death, protein 4 (PDCD4) expression using quantitative real-time PCR (qRT-PCR). Laser capture microdissection (LCM) of stromal and epithelial tissues and in situ hybridization (ISH) using locked nucleic acid (LNA) probes were performed on a subset of fixed specimens. Cell line experiments were conducted on fibroblasts stimulated in culture media from HeLa cells, which were then assessed for miR-21, PDCD4, IL-6 and α-SMA expression by qRT-PCR. Twenty normal cervical cell, 12 cervicitis, 14 cervical intraepithelial neoplastic I (CIN I), 22 CIN II-III and 43 cervical squamous cell carcinoma (SCC) specimens were investigated. miR-21 levels were significantly lower in normal than in abnormal tissues. The expression of miR-21 in HPV negative normal cytology was significantly lower than in HPV positive samples in abnormal tissue and SCC. The miR-21 expression was significantly higher in HPV negative cervicitis than HPV negative normal cells. LCM and ISH data showed that miR-21 is primarily expressed in the tumor-associated stromal cell microenvironment. Fibroblasts treated with HeLa cell culture media showed up-regulated expression of miR-21, which correlated with increased expression of α-SMA and IL-6 and with down-regulation of PDCD4. These results demonstrate that miR-21 is associated with HPV infection and involved in cervical lesions as well as cervicitis and its up-regulation in tumor-stroma might be involved in the inflammation process and cervical cancer progression.

Genomic landscape of human papillomavirus-associated cancers

Recent next-generation sequencing studies have generated a comprehensive overview of the genomic landscape of human papillomavirus (HPV)-associated cancers. This review summarizes these findings to provide insight into the tumor biology of these cancers and potential therapeutic opportunities for HPV-driven malignancies. In addition to the tumorigenic properties of the HPV oncoproteins, integration of HPV DNA into the host genome is suggested to be a driver of the neoplastic process. Integration may confer a growth and survival advantage via enhanced expression of viral oncoproteins, alteration of critical cellular genes, and changes in global promoter methylation and transcription. Alteration of cellular genes may lead to loss of function of tumor suppressor genes, enhanced oncogene expression, loss of function of DNA repair genes, or other vital cellular functions. Recurrent integrations in RAD51B, NR4A2, and TP63, leading to aberrant forms of these proteins, are observed in both HPV-positive head and neck squamous cell carcinoma (HNSCC) and cervical carcinoma. Additional genomic alterations, independent of integration events, include recurrent PIK3CA mutations (and aberrations in other members of the PI3K pathway), alterations in receptor tyrosine kinases (primarily FGFR2 and FGFR3 in HPV-positive HNSCC, and ERBB2 in cervical squamous cell carcinoma), and genes in pathways related to squamous cell differentiation and immune responses. A number of the alterations identified are potentially targetable, which may lead to advances in the treatment of HPV-associated cancers.

A high-throughput cellular assay to quantify the p53-degradation activity of E6 from different human papillomavirus types

A subset of human papillomaviruses (HPVs), known as the high-risk types, are the causative agents of cervical cancer and other malignancies of the anogenital region and oral mucosa. The capacity of these viruses to induce cancer and to immortalize cells in culture relies in part on a critical function of their E6 oncoprotein, that of promoting the poly-ubiquitination of the cellular tumor suppressor protein p53 and its subsequent degradation by the proteasome. Here, we describe a cellular assay to measure the p53-degradation activity of E6 from different HPV types. This assay is based on a translational fusion of p53 to Renilla luciferase (Rluc-p53) that remains sensitive to degradation by high-risk E6 and whose steady-state levels can be accurately measured in standard luciferase assays. The p53-degradation activity of any E6 protein can be tested and quantified in transiently transfected cells by determining the amount of E6-expression vector required to reduce by half the levels of RLuc-p53 luciferase activity (50 % effective concentration [EC50]). The high-throughput and quantitative nature of this assay makes it particularly useful to compare the p53-degradation activities of E6 from several HPV types in parallel.

Methods to assess the nucleocytoplasmic shuttling of the HPV E1 helicase and its effects on cellular proliferation and induction of a DNA damage response

Replication of the human papillomavirus (HPV) double-stranded DNA genome in the nucleus of infected cells relies on the viral proteins E1 and E2 in conjunction with the host DNA replication machinery. This process is tightly linked to the replication of cellular DNA, in part through the cyclin-dependent phosphorylation of E1, which inhibits its export out of the nucleus to promote its accumulation in this compartment during S-phase. It has been recently shown that accumulation of E1 in the nucleus, while a prerequisite for viral DNA replication, leads to the inhibition of cellular proliferation and the activation of a DNA damage response (DDR). Here we describe methods to monitor the subcellular localization of E1 and to assess the deleterious effects of its nuclear accumulation on cellular proliferation, cell cycle progression and the induction of a DDR, using a combination of colony formation assays, immunofluorescence microcopy, and flow cytometry approaches.

Interplay between genetic and epigenetic factors governs common fragile site instability in cancer

Common fragile sites (CFSs) are regions within the normal chromosomal structure that were characterized as hotspots for genomic instability in cancer almost 30 years ago. In recent years, many efforts have been made to understand the basis of CFS fragility and their involvement in the genomic signature of instability found in malignant tumors. CFSs are among the first regions to undergo genomic instability during cancer development because of their intrinsic sensitivity to replication stress conditions, which result from oncogene expression. The preferred sensitivity of CFSs to replication stress stems from various mechanisms including: replication fork arrest at AT-rich repeats, origin paucity along large genomic regions, failure in activation of dormant origins, late replication timing, collision between replication and transcription along large genes, all leading to incomplete replication of the CFS region and resulting in chromosomal instability. Here we review shared and unique characteristics of CFSs, their underlying causes and implications, particularly for the development of cancer.