Human Papillomavirus In Pathogenesis Research Articles

HPV Infections-Classification, Pathogenesis, and Potential New Therapies.

To date, more than 400 types of human papillomavirus (HPV) have been identified. Despite the creation of effective prophylactic vaccines against the most common genital HPVs, the viruses remain among the most prevalent pathogens found in humans. According to WHO data, they are the cause of 5% of all cancers. Even more frequent are persistent and recurrent benign lesions such as genital and common warts. HPVs are resistant to many disinfectants and relatively unsusceptible to external conditions. There is still no drug available to inhibit viral replication, and treatment is based on removing lesions or stimulating the host immune system. This paper presents the systematics of HPV and the differences in HPV structure between different genetic types, lineages, and sublineages, based on the literature and GenBank data. We also present the pathogenesis of diseases caused by HPV, with a special focus on the role played by E6, E7, and other viral proteins in the development of benign and cancerous lesions. We discuss further prospects for the treatment of HPV infections, including, among others, substances that block the entry of HPV into cells, inhibitors of viral early proteins, and some substances of plant origin that inhibit viral replication, as well as new possibilities for therapeutic vaccines.

HPV pathogenesis, various types of vaccines, safety concern, prophylactic and therapeutic applications to control cervical cancer, and future perspective.

Over 98% of cervical cancers (CC) are caused by regular infections with "high risk" genotype of the human papilloma virus (HPV). However, this is not always the causative factor. Therefore, production of HPV vaccinations represents a significant chance to minimize the risk of CC. Phase III studies for a number of preventative HPV vaccines based on L1-virus-like particle (VLPs) have just been completed and the preliminary results are very convincing. However, there are a lot of practical concerns that need to be resolved before the use of these vaccinations. These vaccines were challenged with obvious queries such as protection time, subject receiving vaccines, time of vaccination, and how to include them into ongoing screening programs. Although these vaccines were 90% effective at preventing HPV infection as these offered only modest advantages for the removal of pre-existing infections. New advancements in the creation of therapeutic vaccinations have been explored for further improvement and post-vaccination surveillance. Therapeutic vaccines attempted to boost cell-mediated immunities and these are detrimental to the infected cell as opposed to neutralizing antibodies (different from prophylactic vaccines).

Updates in Cervical Cancer Screening Guidelines, The Bethesda System for Reporting Cervical Cytology, and Clinical Management Recommendations.

Over the past decades, cervical cancer has been a worldwide public health problem. Population-based early cancer risk detection and prevention approaches, including vaccination, cytology screening and human papilloma virus (HPV) detection, with the aligned clinical management, have formed a well-rounded high-quality implementation system for cervical cancer control, and revolutionarily improved the quality of life of women: (1) the success of cervical cancer screening practices, (2) standardization of The Bethesda system for reporting cervicovaginal cytology, (3) improvement in the understanding of HPV pathogenesis in cervical cancer, and (4) the development of appropriate management approaches have significantly decreased the disease burden of cervical cancer worldwide. This scoping review aimed to understand the evolvement of cervical cancer screening and management guidelines, describe the Bethesda cervical cytology reporting system, and HPV vaccines and tests, and highlight the key information of present policies and practices.

Human papillomavirus in the setting of immunodeficiency: Pathogenesis and the emergence of next-generation therapies to reduce the high associated cancer risk.

Human papillomavirus (HPV), a common sexually transmitted virus infecting mucosal or cutaneous stratified epithelia, is implicated in the rising of associated cancers worldwide. While HPV infection can be cleared by an adequate immune response, immunocompromised individuals can develop persistent, treatment-refractory, and progressive disease. Primary immunodeficiencies (PIDs) associated with HPV-related disease include inborn errors of GATA, EVER1/2, and CXCR4 mutations, resulting in defective cellular function. People living with secondary immunodeficiency (e.g. solid-organ transplants recipients of immunosuppression) and acquired immunodeficiency (e.g. concurrent human immunodeficiency virus (HIV) infection) are also at significant risk of HPV-related disease. Immunocompromised people are highly susceptible to the development of cutaneous and mucosal warts, and cervical, anogenital and oropharyngeal carcinomas. The specific mechanisms underlying high-risk HPV-driven cancer development in immunocompromised hosts are not well understood. Current treatments for HPV-related cancers include surgery with adjuvant chemotherapy and/or radiotherapy, with clinical trials underway to investigate the use of anti-PD-1 therapy. In the setting of HIV co-infection, persistent high-grade anal intraepithelial neoplasia can occur despite suppressive antiretroviral therapy, resulting in an ongoing risk for transformation to overt malignancy. Although therapeutic vaccines against HPV are under development, the efficacy of these in the setting of PID, secondary- or acquired- immunodeficiencies remains unclear. RNA-based therapeutic targeting of the HPV genome or mRNA transcript has become a promising next-generation therapeutic avenue. In this review, we summarise the current understanding of HPV pathogenesis, immune evasion, and malignant transformation, with a focus on key PIDs, secondary immunodeficiencies, and HIV infection. Current management and vaccine regimes are outlined in relation to HPV-driven cancer, and specifically, the need for more effective therapeutic strategies for immunocompromised hosts. The recent advances in RNA-based gene targeting including CRISPR and short interfering RNA (siRNA), and the potential application to HPV infection are of great interest. An increased understanding of both the dysregulated immune responses in immunocompromised hosts and of viral persistence is essential for the design of next-generation therapies to eliminate HPV persistence and cancer development in the most at-risk populations.

HPV and Cervical Cancer: A Review of Epidemiology and Screening Uptake in the UK.

Cervical cancer is the fourth most common malignancy in females worldwide, and a leading cause of death in the United Kingdom (UK). The human papillomavirus (HPV) is the strongest risk factor for developing cervical intraepithelial neoplasia and cancer. Across the UK, the national HPV immunisation programme, introduced in 2008, has been successful in protecting against HPV-related infections. Furthermore, the National Health Service (NHS) implemented the cytology-based cervical cancer screening service to all females aged 25 to 64, which has observed a decline in cervical cancer incidence. In the UK, there has been an overall decline in age-appropriate coverage since April 2010. In 2019, the COVID-19 pandemic disrupted NHS cancer screening and immunisation programmes, leading to a 6.8% decreased uptake of cervical cancer screening from the previous year. Engagement with screening has also been associated with social deprivation. In England, incidence rates of cervical cancer were reported to be 65% higher in the most deprived areas compared to the least, with lifestyle factors such as cigarette consumption contributing to 21% of cervical cancer cases. In this article, we provide an update on the epidemiology of cervical cancer, and HPV pathogenesis and transmission, along with the current prevention programmes within the NHS.

Progress of research on human papilloma virus vaccine application

Human papillomavirus (HPV) infection is a huge and serious topic in China and around the world with innumerable infections every year, which seriously endanger the lives of women all over the world. This article focuses on the pathogenesis of HPV, the types of HPV vaccines and their mechanism of action, as well as an analysis of the existing problems and an outlook on the future.Great progress have been made globally in order to decrease the HPV infection rate of women around the world, and this article provides additional possibilities for the development of future vaccines and solutions to existing problems.

Modeling HPV-Associated Disease and Cancer Using the Cottontail Rabbit Papillomavirus.

Approximately 5% of all human cancers are attributable to human papillomavirus (HPV) infections. HPV-associated diseases and cancers remain a substantial public health and economic burden worldwide despite the availability of prophylactic HPV vaccines. Current diagnosis and treatments for HPV-associated diseases and cancers are predominantly based on cell/tissue morphological examination and/or testing for the presence of high-risk HPV types. There is a lack of robust targets/markers to improve the accuracy of diagnosis and treatments. Several naturally occurring animal papillomavirus models have been established as surrogates to study HPV pathogenesis. Among them, the Cottontail rabbit papillomavirus (CRPV) model has become known as the gold standard. This model has played a pivotal role in the successful development of vaccines now available to prevent HPV infections. Over the past eighty years, the CRPV model has been widely applied to study HPV carcinogenesis. Taking advantage of a large panel of functional mutant CRPV genomes with distinct, reproducible, and predictable phenotypes, we have gained a deeper understanding of viral–host interaction during tumor progression. In recent years, the application of genome-wide RNA-seq analysis to the CRPV model has allowed us to learn and validate changes that parallel those reported in HPV-associated cancers. In addition, we have established a selection of gene-modified rabbit lines to facilitate mechanistic studies and the development of novel therapeutic strategies. In the current review, we summarize some significant findings that have advanced our understanding of HPV pathogenesis and highlight the implication of the development of novel gene-modified rabbits to future mechanistic studies.

An overview of the general characteristics, pathogenicity, transmission, and diagnosis of human papilloma virus (HPV)

Mucous membrane infections are brought on by the double-standard DNA virus known as human papillomavirus (HPV). Cervix cell alterations are caused by a sexually transmitted illness. E6 and E7 oncogenes play a critical role in HPV infection. Finding these genes to identify HPV strains, particularly the HPV16 strain, will have a significant impact due to its exceptional sensitivity, the dielectric electrochemical biosensor stands out among other pathogen detection methods. Recent evidence suggests that E6 and E7 are also important in inhibiting the innate immune response of the host cell to HPV. Viral replication is mediated by the E1 and E2 proteins in conjunction with other biological stimuli. E2 has also been linked to viral and cellular transcriptional regulation. Despite decades of research, the function of other viral proteins still remains unclear. Therefore, analysis of Human Papilloma Virus (HPV) characteristics, pathogenicity, transmission and diagnosis were reviewed. We concluded that we now have the tools and methodologies necessary to answer this critical question about viral tropism. The discovery of efficient treatments to cure or prevent HPV-induced illness is just as vital as studying the underlying mechanisms of HPV pathogenesis. The identification of drugs specifically to treat HPV infection has not been highly successful due to the complexities of the HPV life cycle and the limited number of enzymatic activities identified for HPV proteins. The development of drug treatments for existing HPV disease is an important undertaking that deserves further attention. In this regard, the development of therapeutic vaccines and self-protection are promising area of investigation and needs to be further supported.

Abstract 5733: Targeting nonsense-mediated decay restores p53 function in HPV-associated head and neck cancers

Abstract HPV-positive (HPV+) head and neck squamous cell carcinoma (HNSCC) tumors typically have p53 loss due to the activity of the human papillomavirus (HPV)-encoded E6 protein and the E6-associated protein (HPVE6-AP) which mediate the degradation of wild-type (WT) p53 (p53α). The loss of p53 is thought to be a major contributor to the pathogenesis of HPV+ HNSCC, which comprise approximately 35% of all HNSCC. Currently, standard care for HPV+HNSCC includes radiation and chemotherapy. However long-term toxicity related to these treatments is a concern, and there is a need for newer therapeutic strategies. Previously, we reported that two alternatively spliced, functional truncated isoforms of p53 (p53β and p53γ, comprising of exons 1 to 9β or 9γ, respectively) are degraded by nonsense-mediated decay (NMD), a regulator of aberrant mRNA stability. Here, using HPV+HNSCC cell line models, we show that NMD inhibition rescues p53β/γ isoforms and activates p53 pathway. Furthermore, we show that p53β/γ isoforms are more stable compared to p53α in these cells, with reduced vulnerabililty to HPVE6-AP- mediated degradation, and that p53β/γ isoforms contribute to increased expression of p53 transcriptional targets p21 and PUMA following NMD inhibition. Consistent with p53 pathway activation, NMD inhibition enhanced radiosensitivity of HNSCC cells. NMD inhibition attenuated colony forming ability and disrupted cell cycle progression. To evaluate the therapeutic implications of NMD inhibition, we assessed the in vivo growth of HPV+ UMSCC47 tumors. Nude mice were injected with UMSCC47 cells either subcutaneously or orthotopically in the tongue and randomized to receive vehicle or with an NMD inhibitor. In both tumor models, we observed a significant reduction in tumor volume with NMD inhibition as compared to the vehicle-treated animals. To investigate whether NMD inhibition induced the expression of p53β/γ isoforms and activated the p53 pathway in vivo, we collected tumor tissues from animals and evaluated expression of p53 isoforms and transcriptional targets by RT-PCR. We observed increased expression of p53γ, p21, GADD45A and PUMA mRNAs in NMD inhibitor treated UMSCC47 tumors, compared to their respective vehicle treated controls. These results identify NMD inhibition as a novel therapeutic strategy for restoration of p53 function in major subgroups of p53-deficient HPV+ HNSCC tumors. Citation Format: Jayanthi Gudikote, Tina Cascone, Alissa Poteete, Piyada Sitthideatphaiboon, Sonia Patel, Yan Yang, Fahao Zhang, Lerong Li, Li Shen, Monique Nilsson, Phillip Jones, Jing Wang, Jean-Christophe Bourdon, Faye M. Johnson, John V. Heymach. Targeting nonsense-mediated decay restores p53 function in HPV-associated head and neck cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5733.

ATM Pathway Is Essential for HPV-Positive Human Cervical Cancer-Derived Cell Lines Viability and Proliferation.

Infection with some mucosal human papillomavirus (HPV) types is the etiological cause of cervical cancer and of a significant fraction of vaginal, vulvar, anal, penile, and head and neck carcinomas. DNA repair machinery is essential for both HPV replication and tumor cells survival suggesting that cellular DNA repair machinery may play a dual role in HPV biology and pathogenesis. Here, we silenced genes involved in DNA Repair pathways to identify genes that are essential for the survival of HPV-transformed cells. We identified that inhibition of the ATM/CHK2/BRCA1 axis selectively affects the proliferation of cervical cancer-derived cell lines, without altering normal primary human keratinocytes (PHK) growth. Silencing or chemical inhibition of ATM/CHK2 reduced the clonogenic and proliferative capacity of cervical cancer-derived cells. Using PHK transduced with HPV16 oncogenes we observed that the effect of ATM/CHK2 silencing depends on the expression of the oncogene E6 and on its ability to induce p53 degradation. Our results show that inhibition of components of the ATM/CHK2 signaling axis reduces p53-deficient cells proliferation potential, suggesting the existence of a synthetic lethal association between CHK2 and p53. Altogether, we present evidence that synthetic lethality using ATM/CHK2 inhibitors can be exploited to treat cervical cancer and other HPV-associated tumors.

MiR-12 Derived from Bone Marrow Mesenchymal Stem Cells Accelerates the Development of Human Papillomavirus by Up-Regulating AN1

The miRNA derived from Bone marrow mesenchymal stem cells (BMSCs) have crucial effects on tumors. The tumor could be affected by the abnormal expression of miRNA in human papillomavirus (HPV). Our study aimed to identify the potential brand-new biomarker in order to reveal the pathogenesis of HPV. miRNA derived from BMSCs was detected and identified. The action of miR-12 on biological behavior of HPV was detected. The level of AN1 protein was detected by Western-blot and IHC method. The relationship between miR-12 and AN1 was assessed by bioinformatics analysis and luciferase assay. The tumor cell biological behaviors were evaluated by manipulating miR12 and AN1 level. The tumor volume derived from BMSCs was diminished significantly compared with normal tissues. The tumor volume was bigger after combined injection with Hela cell and miR-12 compared with single injection. The cell proliferative and invasive ability was strengthened after transfection with miR-12mimics. The cell invasive ability was reduced significantly after transfection of si-miR-12. AN1 was a target gene of miR-12 as confirmed by the analysis on bioinformatics and luciferase activity. The phenotype was reversed after the silent presentation of AN1 was disturbed. In conclusion, miR-12 expression is elevated in HPV cells and affects HPV cells through targeting the AN1 signaling pathway.

Ethiology and Pathophysiology of Whart Hpv Infection: A Review Article

Genital Human Papillomavirus (HPV) infection is a self-limiting and often asymptomatic disease. Genital HPV infection is divided into high-risk HPV (HPV 16 and 18) and low-risk HPV (HPV 6 and 11). Low-risk or non-oncogenic HPV produces a clinical picture of anogenital warts, which may be condylomatous, papules, or keratotic. The subclinical form of genital HPV infection can present with an "aceto-white" lesion found on the cervix that will appear when examined using an acetic acid solution evaluated by colposcopy. Based on the association with cervical cancer and precursor lesions, HPV can also be classified as high-risk (HR-HPV) and low-risk (LR-HPV) oncogenic types. LR-HPV types, such as HPV 6 and 11, can cause generalized genital warts or benign hyperproliferative lesions with a very limited predisposition to malignant progression, while infection with HR-HPV types, HPV 16 and 18, is associated with the development of pre-malignant and cervical lesions. Discussion: Human Papillomavirus is a small DNA virus (50-55nm) belonging to the family Papillomaviridae and genus Papillomavirus. Human papillomavirus (HPV) is a relatively small non-enveloped virus containing a double-stranded circular DNA genome associated with histone-like proteins and protected by a capsid formed by two final proteins, L1 and L2. Each capsid consists of 72 capsomeres, The pathogenesis of HPV begins with infection of stem cells in the basal layer of the epithelium. Once inside the cell, the virus requires expression of the E1 and E2 genes to maintain a low genome copy number. These proteins bind to the origin of replication and the virus secretes cellular DNA polymerases and other proteins required for DNA replication. In the suprabasal layer, the expression of genes E1, E2, E5, E6 and E7 contributes to the maintenance of the viral genome and induces cell proliferation, increasing the number of HPV-infected cells in the epithelium, resulting in a higher number of cells that will eventually produce infectious virions. Conclusion: In benign HPV lesions, cell proliferation increases leading to increased nutrition, resulting in competition for nutrients and oxygen. Both HR-HPV and LR-HPV E7 proteins increase the level of the transcription factor Hypoxia-inducible factor-1 (HIF-1), and induce increased expression of HIF-1 target genes under hypoxic conditions. Increased HIF-1 activity results in increased transcription of a subset of genes that support angiogenesis, and the induction of this angiogenesis is critical for the persistence and growth of HPV lesions such as genital warts.

Prediction of Human proteins having interactions with HPV16 proteins using virus and host sequence motifs.

Background: Human Papillomavirus (HPV) infection has been found to be the major cause of cancer of cervical region, in females. Genome of HPV codes for 6 functional proteins E1, E2, E4, E5, E6 and E7. These proteins play different roles in development of HPV infection and its progression towards cervical cancer. The interactions of HPV proteins with human DNA and proteins occurs in the presence of short linear peptide motifs on these proteins, have similar sequence to those found on proteins in human cells.
 Methods: After identification of human motifs in HPV proteins, by use of ELM resource, their counter domains were found from PROSITE. The proteins of human proteome containing these counter domains were predicted as the proteins having possibility of interactions with HPV proteins. 
 Results: we predicted 9468 human proteins for having interactions with HPV proteins. Our predicted proteins were enriched with the host proteins having possibility of being interacted by HPV proteins. 10% of our predicted proteins were already reported to be affected by one or more HPV proteins. The list of predicated proteins can be utilized to find out the connectivity between the virus HPV and human host. It can also be used to determine the pathways involved in pathogenesis of HPV leading towards the cervical cancer
 Conclusion: The list of predicated proteins can be utilized to find out the connectivity between the virus HPV and human host. It can also be used to determine the pathways involved in pathogenesis of HPV leading towards the cervical cancer.

Identification of a peptide that disrupts hADA3-E6 interaction with implications in HPV induced cancer therapy

AimHigh risk Human Papillomavirus (HPV) is an infectious pathogen implicated in a variety of cancers with poor clinical outcome. The mechanism of HPV induced cellular transformation and its intervention remains to be elucidated. Human ADA3 (hADA3), a cellular target of HPV16 E6, is an essential and conserved component of the ADA transcriptional coactivator complex. High risk HPV-E6 binds and functionally inactivates hADA3 to initiate oncogenesis. The aim of this study was to identify the interaction interface between hADA3 and HPV16E6 for designing inhibitory peptides that can potentially disrupt the hADA3-E6 interaction. Material methodsThe present investigation employed structure-based in silico tools supported by biochemical validation, in vivo interaction studies and analysis of posttranslational modifications. Key findingsFirst 3D-model of hADA3 was proposed and domains involved in the oncogenic interaction between hADA3 and HPV16E6 were delineated. Rationally designed peptide disrupted hADA3-E6 interaction and impeded malignant properties of cervical cancer cells. SignificanceIntervention of hADA3-E6 interaction thus promises to be a potential strategy to combat HPV induced oncogenic conditions like cervical cancer. The investigation provides mechanistic insights into HPV pathogenesis and shows promise in developing novel therapeutics to treat HPV induced cancers.

Blocking of EGFR Signaling Is a Latent Strategy for the Improvement of Prognosis of HPV-Induced Cancer.

Human papillomavirus (HPV) is a double-stranded DNA (dsDNA) virus, and its high-risk subtypes increase cancer risks. However, the mechanism of HPV infection and pathogenesis still remain unclear. Therefore, understanding the molecular mechanisms and the pathogenesis of HPV are crucial in the prevention of HPV-related cancers. In this study, we analyzed cervix squamous cell carcinoma (CESC) and head and neck carcinoma (HNSC) combined data to investigate various HPV-induced cancer common features. We showed that epidermal growth factor receptor (EGFR) was downregulated in HPV-positive (HPV+) cancer, and that HPV+ cancer patients exhibited better prognosis than HPV-negative (HPV−) cancer patients. Our study also showed that TP53 mutation rate is lower in HPV+ cancer than in HPV− cancer and that TP53 can be modulated by HPV E7 protein. However, there was no significant difference in the expression of wildtype TP53 in both groups. Subsequently, we constructed HPV-human interaction network and found that EGFR is a critical factor. From the network, we also noticed that EGFR is regulated by HPV E7 protein and hsa-miR-944. Moreover, while phosphorylated EGFR is associated with a worse prognosis, EGFR total express level is not significantly correlated with prognosis. This indicates that EGFR activation will induce a worse outcome in HPV+ cancer patients. Further enrichment analysis showed that EGFR downstream pathway and cancer relative pathway are diversely activated in HPV+ cancer and HPV− cancer. In summary, HPV E7 protein downregulates EGFR that downregulates phosphorylated EGFR and inhibit EGFR-related pathways which in turn and consequently induce better prognosis.

Identification of four key prognostic genes and three potential drugs in human papillomavirus negative head and neck squamous cell carcinoma

BackgroundHead and neck squamous cell carcinoma (HNSCC) is a common tumor worldwide with poor prognosis. The pathogenesis of human papillomavirus (HPV)-positive and HPV-negative HNSCCs differs. However, few studies have considered the HPV status when identifying biomarkers for HNSCC. Thus, the identification of biomarkers for HPV-positive and HPV-negative HNSCCs is urgently needed.MethodsThree microarray datasets from Gene Expression Omnibus (GEO) were analyzed, and the differentially expressed genes (DEGs) were obtained. Then, functional enrichment pathway analysis was performed and protein–protein interaction (PPI) networks were constructed. The expression of hub genes at both the mRNA and protein level was determined in Oncomine, The Cancer Genome Atlas (TCGA) and the Human Protein Atlas (HPA). In addition, survival analysis of the patient stratified by HPV status and the expression levels of key genes were performed based on TCGA data. The role of AREG, STAG3, CAV1 and C19orf57 in cancer were analyzed through Gene set enrichment analysis (GSEA). The top ten small molecule drugs were identified and the therapeutic value of zonisamide, NVP-AUY922, PP-2 and fostamatinib was further evaluated in six HPV-negative HNSCC cell lines. Finally, the therapeutic value of NVP-AUY922 was tested in vivo based on three HPV-negative HNSCC models, and statistical analysis was performed.ResultsIn total, 47 DEGs were obtained, 11 of which were identified as hub genes. Biological process analysis indicated that the hub genes were associated with the G1/S transition of the mitotic cell cycle. Survival analysis uncovered that the prognostic value of AREG, STAG3, C19orf57 and CAV1 differed between HPV-positive and HPV-negative patients. Gene set enrichment analysis (GSEA) showed the role of AREG, STAG3 and CAV1 in dysregulated pathways of tumor. Ten small molecules were identified as potential drugs specifically for HPV-positive or HPV-negative patients; three—NVP-AUY922, fostamatinib and PP-2—greatly inhibited the proliferation of six HPV-negative HNSCC cell lines in vitro, and NVP-AUY922 inhibited three HPV-negative HNSCC xenografts in vivo.ConclusionsIn conclusion, AREG, STAG3, C19orf57 and CAV1 are key prognostic factors and potential therapeutic targets in HPV-negative HNSCC. NVP-AUY922, fostamatinib and PP-2 may be effective drugs for HPV-negative HNSCC.

Topoisomerase 2β Induces DNA Breaks To Regulate Human Papillomavirus Replication.

Topoisomerases regulate higher-order chromatin structures through the transient breaking and religating of one or both strands of the phosphodiester backbone of duplex DNA. TOP2β is a type II topoisomerase that induces double-strand DNA breaks at topologically associated domains (TADS) to relieve torsional stress arising during transcription or replication. TADS are anchored by CCCTC-binding factor (CTCF) and SMC1 cohesin proteins in complexes with TOP2β. Upon DNA cleavage, a covalent intermediate DNA-TOP2β (TOP2βcc) is transiently generated to allow for strand passage. The tyrosyl-DNA phosphodiesterase TDP2 can resolve TOP2βcc, but failure to do so quickly can lead to long-lasting DNA breaks. Given the role of CTCF/SMC1 proteins in the human papillomavirus (HPV) life cycle, we investigated whether TOP2β proteins contribute to HPV pathogenesis. Our studies demonstrated that levels of both TOP2β and TDP2 were substantially increased in cells with high-risk HPV genomes, and this correlated with large amounts of DNA breaks. Knockdown of TOP2β with short hairpin RNAs (shRNAs) reduced DNA breaks by over 50% as determined through COMET assays. Furthermore, this correlated with substantially reduced formation of repair foci such as phosphorylated H2AX (γH2AX), phosphorylated CHK1 (pCHK1), and phosphorylated SMC1 (pSMC1) indicative of impaired activation of DNA damage repair pathways. Importantly, knockdown of TOP2β also blocked HPV genome replication. Our previous studies demonstrated that CTCF/SMC1 factors associate with HPV genomes at sites in the late regions of HPV31, and these correspond to regions that also bind TOP2β. This study identifies TOP2β as responsible for enhanced levels of DNA breaks in HPV-positive cells and as a regulator of viral replication.IMPORTANCE High-risk human papillomaviruses (HPVs) infect epithelial cells and induce viral genome amplification upon differentiation. HPV proteins activate DNA damage repair pathways by inducing high numbers of DNA breaks in both viral and cellular DNAs. This activation is required for HPV genome replication. TOP2β is a type II topoisomerase that induces double-strand DNA breaks at topologically associated domains (TADS) to relieve torsional stress arising during transcription or replication. Our studies demonstrate that TOP2β levels are increased in HPV-positive cells and that this is required for HPV replication. Importantly, our studies further show that knockdown of TOP2β reduces the number of breaks by over 50% in HPV-positive cells and that this correlates with substantially impaired activation of DNA repair pathways. This study identifies a critical mechanism by which HPV replication is regulated by the topoisomerase TOP2β through DNA break formation.

CXCR4 signaling controls dendritic cell location and activation at steady state and in inflammation

AbstractDendritic cells (DCs) encompass several cell subsets that collaborate to initiate and regulate immune responses. Proper DC localization determines their function and requires the tightly controlled action of chemokine receptors. All DC subsets express CXCR4, but the genuine contribution of this receptor to their biology has been overlooked. We addressed this question using natural CXCR4 mutants resistant to CXCL12-induced desensitization and harboring a gain of function that cause the warts, hypogammaglobulinemia, infections, and myelokathexis (WHIM) syndrome (WS), a rare immunodeficiency associated with high susceptibility to the pathogenesis of human papillomavirus (HPV). We report a reduction in the number of circulating plasmacytoid DCs (pDCs) in WHIM patients, whereas that of conventional DCs is preserved. This pattern was reproduced in an original mouse model of WS, enabling us to show that the circulating pDC defect can be corrected upon CXCR4 blockade and that pDC differentiation and function are preserved, despite CXCR4 dysfunction. We further identified proper CXCR4 signaling as a critical checkpoint for Langerhans cell and DC migration from the skin to lymph nodes, with corollary alterations of their activation state and tissue inflammation in a model of HPV-induced dysplasia. Beyond providing new hypotheses to explain the susceptibility of WHIM patients to HPV pathogenesis, this study shows that proper CXCR4 signaling establishes a migration threshold that controls DC egress from CXCL12-containing environments and highlights the critical and subset-specific contribution of CXCR4 signal termination to DC biology.

Human Papillomavirus-Associated Cancers.

Human Papillomavirus (HPV) is the causative agent in the majority of anal, head and neck, oral, oropharyngeal, penile, vaginal, vulvar, and cervical cancers. Cervical cancer is the fourth most common cancer among women worldwide. Of all diagnosed human malignant neoplasms, approximately 4.5% are attributable to HPV, including cervical, anal cancers, vaginal, vulvar, penile, and oropharyngeal cancers. Over 182 HPV types have been identified and sequenced to date however, only certain types of HPV are more frequent in malignant lesions and considered to be a major risk factor in the development of some cancers. Because most HPV infections are transient, and an individual's immunocompetent may clear the infection, HPV infection has received little attention from clinicians, the general public, or policy makers. This lack of attention may underpin a deadly and increasing problem because each newly acquired infection has the potential to persist and become an incurable, lifelong affliction. In addition, no successful treatment of HPV infection currently exists despite the great strides toward understanding the mechanisms underlying HPV pathogenesis. Moreover, ample research has proven that the use of prophylactic vaccines, such as Gardasil and Cervarix, have led to documented progress in decreasing the burden of HPV infection, however not all countries introduced a government-funded National HPV Vaccination Program to protect young men and women. This chapter summarizes the HPV infection, detection and prevention. We also shed light on non-cervical HPV-related cancers, which is rapidly increasing in more developed countries toward cervical cancer.

The early detection of cervical cancer. The current and changing landscape of cervical disease detection.

Cervical cancer prevention has undergone dramatic changes over the past decade. With the introduction of human papillomavirus (HPV) vaccination, some countries have seen a dramatic decline in HPV-mediated cervical disease. However, widespread implementation has been limited by economic considerations and the varying healthcare priorities of different countries, as well as by vaccine availability and, in some instances, vaccine hesitancy amongst the population/government. In this environment, it is clear that cervical screening will retain a critical role in the prevention of cervical cancer and will in due course need to adapt to the changing incidence of HPV-associated neoplasia. Cervical screening has, for many years, been performed using Papanicolaou staining of cytology samples. As our understanding of the role of HPV in cervical cancer progression has advanced, and with the availability of sensitive detection systems, cervical screening now incorporates HPV testing. Although such tests improve disease detection, they are not specific, and cannot discriminate high-grade from low-grade disease. This has necessitated the development of effective triage approaches to stratify HPV-positive women according to their risk of cancer progression. Although cytology triage remains the mainstay of screening, novel strategies under evaluation include DNA methylation, biomarker detection and the incorporation of artificial intelligence systems to detect cervical abnormalities. These tests, which can be partially anchored in a molecular understanding of HPV pathogenesis, will enhance the sensitivity of disease detection and improve patient outcomes. This review will provide insight on these innovative methodologies while explaining their scientific basis drawing from our understanding of HPV tumour biology.