Human papillomavirus oncoproteins and post-translational modifications: generating multifunctional hubs for overriding cellular homeostasis

2020 ◽  
Vol 401 (5) ◽  
pp. 585-599 ◽  
Author(s):  
Om Basukala ◽  
Vanessa Sarabia-Vega ◽  
Lawrence Banks
Keyword(s):  
Cervical Cancer ◽  
Human Papillomavirus ◽  
Life Cycle ◽  
Growth Control ◽  
Viral Proteins ◽  
Mechanisms Of Action ◽  
Human Papillomaviruses ◽  
Post Translational Modifications ◽  
E6 And E7 ◽  
Hpv Oncoproteins

AbstractHuman papillomaviruses (HPVs) are major human carcinogens, causing around 5% of all human cancers, with cervical cancer being the most important. These tumors are all driven by the two HPV oncoproteins E6 and E7. Whilst their mechanisms of action are becoming increasingly clear through their abilities to target essential cellular tumor suppressor and growth control pathways, the roles that post-translational modifications (PTMs) of E6 and E7 play in the regulation of these activities remain unclear. Here, we discuss the direct consequences of some of the most common PTMs of E6 and E7, and how this impacts upon the multi-functionality of these viral proteins, and thereby contribute to the viral life cycle and to the induction of malignancy. Furthermore, it is becoming increasingly clear that these modifications, may, in some cases, offer novel routes for therapeutic intervention in HPV-induced disease.

scholarly journals Human Papillomavirus E6/E7 and Long Noncoding RNA TMPOP2 Mutually Upregulated Gene Expression in Cervical Cancer Cells

2019 ◽  
Vol 93 (8) ◽  
Author(s):  
Hongpeng He ◽  
Xiang Liu ◽  
Yue Liu ◽  
Mengmeng Zhang ◽  
Yongwei Lai ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cell Cycle ◽  
Cervical Cancer ◽  
Human Papillomavirus ◽  
Cancer Cells ◽  
Long Noncoding Rna ◽  
Noncoding Rna ◽  
Human Papillomaviruses ◽  
Cervical Cancer Cells ◽  
E6 And E7

ABSTRACT TMPOP2 was previously suggested to be an oncogenic long noncoding RNA which is excessively expressed in cervical cancer cells and inhibits E-cadherin gene expression by recruiting transcription repressor EZH2 to the gene promoter. So far, the function and regulation of TMPOP2 in cervical cancer remain largely unknown. Herein, we found that TMPOP2 expression was correlated with human papillomavirus 16/18 (HPV16/18) E6 and E7 in cervical cancer cell lines CaSki and HeLa. Tumor suppressor p53, which is targeted for degradation by HPV16/18, was demonstrated to associate with two p53 response elements in the TMPOP2 promoter to repress the transcription of the TMPOP2 gene. Reciprocally, ectopic expression of TMPOP2 was demonstrated to sequester tumor repressor microRNAs (miRNAs) miR-375 and miR-139 which target HPV16/18 E6/E7 mRNA and resulted in an upregulation of HPV16/18 E6/E7 genes. Thereby, HPV16/18 E6/E7 and the long noncoding RNA (lncRNA) TMPOP2 form a positive feedback loop to mutually derepress gene expression in cervical cancer cells. Moreover, results of RNA sequencing and cell cycle analysis showed that knockdown of TMPOP2 impaired the expression of cell cycle genes, induced cell cycle arrest, and inhibited HeLa cell proliferation. Together, our results indicate that TMPOP2 and HPV16/18 E6/E7 mutually strengthen their expression in cervical cancer cells to enhance tumorigenic activities. IMPORTANCE Human papillomaviruses 16 and 18 (HPV16/18) are the main causative agents of cervical cancer. Viral proteins HPV16/18 E6 and E7 are constitutively expressed in cancer cells to maintain oncogenic phenotypes. Accumulating evidences suggest that HPVs are correlated with the deregulation of long noncoding RNAs (lncRNAs) in cervical cancer, although the mechanism was unexplored in most cases. TMPOP2 is a newly identified lncRNA excessively expressed in cervical cancer. However, the mechanism for the upregulation of TMPOP2 in cervical cancer cells remains largely unknown and its relationship with HPVs is still elusive. The significance of our research is in revealing the mutual upregulation of HPV16/18 E6/E7 and TMPOP2 with the molecular mechanisms explored. This study will expand our understandings of the oncogenic activities of human papillomaviruses and lncRNAs.

scholarly journals Multiple ASF/SF2 Sites in the Human Papillomavirus Type 16 (HPV-16) E4-Coding Region Promote Splicing to the Most Commonly Used 3′-Splice Site on the HPV-16 Genome

2010 ◽  
Vol 84 (16) ◽  
pp. 8219-8230 ◽  
Author(s):  
Monika Somberg ◽  
Stefan Schwartz
Keyword(s):  
Cervical Cancer ◽  
Human Papillomavirus ◽  
Splice Site ◽  
Binding Sites ◽  
Mrna Levels ◽  
Coding Region ◽  
Cervical Lesions ◽  
Hpv 16 ◽  
Human Papillomavirus Type 16 ◽  
E6 And E7

ABSTRACT Our results presented here demonstrate that the most abundant human papillomavirus type 16 (HPV-16) mRNAs expressing the viral oncogenes E6 and E7 are regulated by cellular ASF/SF2, itself defined as a proto-oncogene and overexpressed in cervical cancer cells. We show that the most frequently used 3′-splice site on the HPV-16 genome, site SA3358, which is used to produce primarily E4, E6, and E7 mRNAs, is regulated by ASF/SF2. Splice site SA3358 is immediately followed by 15 potential binding sites for the splicing factor ASF/SF2. Recombinant ASF/SF2 binds to the cluster of ASF/SF2 sites. Mutational inactivation of all 15 sites abolished splicing to SA3358 and redirected splicing to the downstream-located, late 3′-splice site SA5639. Overexpression of a mutant ASF/SF2 protein that lacks the RS domain, also totally inhibited the usage of SA3358 and redirected splicing to the late 3′-splice site SA5639. The 15 ASF/SF2 binding sites could be replaced by an ASF/SF2-dependent, HIV-1-derived splicing enhancer named GAR. This enhancer was also inhibited by the mutant ASF/SF2 protein that lacks the RS domain. Finally, silencer RNA (siRNA)-mediated knockdown of ASF/SF2 caused a reduction in spliced HPV-16 mRNA levels. Taken together, our results demonstrate that the major HPV-16 3′-splice site SA3358 is dependent on ASF/SF2. SA3358 is used by the most abundantly expressed HPV-16 mRNAs, including those encoding E6 and E7. High levels of ASF/SF2 may therefore be a requirement for progression to cervical cancer. This is supported by our earlier findings that ASF/SF2 is overexpressed in high-grade cervical lesions and cervical cancer.

scholarly journals Antibodies against Early Proteins of Human Papillomaviruses as Diagnostic Markers for Invasive Cervical Cancer

1998 ◽  
Vol 36 (2) ◽  
pp. 475-480 ◽  
Author(s):  
Wolfgang Meschede ◽  
Klaus Zumbach ◽  
Joris Braspenning ◽  
Martin Scheffner ◽  
Luis Benitez-Bribiesca ◽  
...  
Keyword(s):  
Cervical Cancer ◽  
Invasive Cervical Cancer ◽  
Human Papillomaviruses ◽  
Antibody Detection ◽  
Diagnostic Tools ◽  
Immunological Monitoring ◽  
Hpv Dna ◽  
Native Proteins ◽  
Human Sera ◽  
E6 And E7

Cervical cancer is the most prevalent tumor in developing countries and the second most frequent cancer among females worldwide. Specific human papillomaviruses (HPVs) and, most notably, HPV types 16 and 18 are recognized as being causally associated with this malignancy. Antibodies against early HPV proteins E6 and E7 have been found more often in patients with tumors than in controls. Existing peptide enzyme-linked immunosorbent assays (ELISAs) for the detection of anti-E6 and anti-E7 antibodies in human sera have low levels of sensitivity and specificity and thus are not suitable for use as diagnostic tools. Based on highly purified recombinant native proteins, we developed four sandwich ELISAs for the detection of antibodies against HPV type 16 and 18 E6 and E7 proteins. We demonstrate their sensitivities and high degrees of specificity for cervical cancer. Among a total of 501 serum specimens from unselected patients with invasive cervical cancer, 52.9% reacted positively in at least one of the four assays. In contrast, among 244 serum specimens from control subjects without cervical cancer, only 2 reactive serum specimens (0.8%) were found. For 19 of 19 antibody-positive patients, the HPV type indicated by seroreactivity was identical to the HPV DNA type found in the tumor, which also indicates a high degree of specificity for antibody detection with respect to HPV type. In a direct comparison of 72 serum specimens from patients with cervical cancer, 56% of the specimens reacted in at least one of the four protein ELISAs, whereas 40% reacted in at least one of seven peptide ELISAs covering the four antigens. These assays could be of value for the detection of invasive cervical cancer in settings in which cytology-based early tumor screening is not available, for the clinical management of patients diagnosed with cervical cancer, and for the immunological monitoring of E6 and E7 vaccination trials.

scholarly journals Acceptability and feasibility of human papillomavirus vaccination for adolescents in school environments in Libreville

2020 ◽  
Vol 9 (9) ◽  
pp. 3541
Author(s):  
Nathalie L. Ambounda ◽  
Sylvain H. Woromogo ◽  
Olive M. Kenmogne ◽  
Felicite E. Yagata Moussa ◽  
Vicky N. Simo Tekem ◽  
...  
Keyword(s):  
Cervical Cancer ◽  
Human Papillomavirus ◽  
High Risk ◽  
Precancerous Lesions ◽  
Hpv Vaccination ◽  
Immunization Coverage ◽  
Human Papillomaviruses ◽  
Professional Status ◽  
Human Papillomavirus Vaccination ◽  
Cross Sectional

Background: High-risk oncogenic human papillomaviruses (HPV) are the cause of sexually transmitted viral infection. Its persistence is a risk factor for precancerous lesions of the cervix, which will constitute the base of cervical cancer. In the world, the prevalence of high-risk oncogenic HPV is 66.7%, which is higher among women starting their sexual activity.Methods: An analytical cross-sectional study was conducted in high schools in Gabon regarding parents. The variables selected were the socio-cultural and demographic characteristics of the parents, their knowledge of human papillomavirus vaccination and their acceptability of HPV vaccination and finally the feasibility of HPV vaccination. The statistical test used was Pearson's Chi-square, and a difference was considered significant for p<0.05.Results: The majority of parents, 89%, were informed of the existence of cervical cancer. However, 73.4% of them were unaware of the existence of vaccination against cervical cancer. Only 2.4% of parents had vaccinated their daughters against cervical cancer at the time of the study. These parents only 53.4% expressed an interest in vaccinating their daughters in 53.4% of cases. The ability to vaccinate children is associated with the socio-professional status of parents (p˂0.000).Conclusions: The majority of parents approved school-based vaccination against human papillomavirus infections despite its reported cost and lack of information. The integration of anti-HPV vaccination into the expanded programme on immunization in Gabon will improve immunization coverage.

scholarly journals SAMHD1 Regulates Human Papillomavirus 16-Induced Cell Proliferation and Viral Replication during Differentiation of Keratinocytes

mSphere ◽  
2019 ◽  
Vol 4 (4) ◽  
Author(s):  
Claire D. James ◽  
Apurva T. Prabhakar ◽  
Raymonde Otoa ◽  
Michael R. Evans ◽  
Xu Wang ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Human Papillomavirus ◽  
Life Cycle ◽  
Viral Replication ◽  
Cellular Proliferation ◽  
Specific Interaction ◽  
Viral Life Cycle ◽  
Human Papillomaviruses ◽  
Cellular Growth ◽  
Human Papillomavirus 16

ABSTRACT Human papillomaviruses induce a host of anogenital cancers, as well as oropharyngeal cancer (HPV+OPC); human papillomavirus 16 (HPV16) is causative in around 90% of HPV+OPC cases. Using telomerase reverse transcriptase (TERT) immortalized foreskin keratinocytes (N/Tert-1), we have identified significant host gene reprogramming by HPV16 (N/Tert-1+HPV16) and demonstrated that N/Tert-1+HPV16 support late stages of the viral life cycle. Expression of the cellular dNTPase and homologous recombination factor sterile alpha motif and histidine-aspartic domain HD-containing protein 1 (SAMHD1) is transcriptionally regulated by HPV16 in N/Tert-1. CRISPR/Cas9 removal of SAMHD1 from N/Tert-1 and N/Tert-1+HPV16 demonstrates that SAMHD1 controls cell proliferation of N/Tert-1 only in the presence of HPV16; the deletion of SAMHD1 promotes hyperproliferation of N/Tert-1+HPV16 cells in organotypic raft cultures but has no effect on N/Tert-1. Viral replication is also elevated in the absence of SAMHD1. This new system has allowed us to identify a specific interaction between SAMHD1 and HPV16 that regulates host cell proliferation and viral replication; such studies are problematic in nonimmortalized primary keratinocytes due to their limited life span. To confirm the relevance of our results, we repeated the analysis with human tonsil keratinocytes (HTK) immortalized by HPV16 (HTK+HPV16) and observed the same hyperproliferative phenotype following CRISPR/Cas9 editing of SAMHD1. Identical results were obtained with three independent CRISPR/Cas9 guide RNAs. The isogenic pairing of N/Tert-1 with N/Tert-1+HPV16, combined with HTK+HPV16, presents a unique system to identify host genes whose products functionally interact with HPV16 to regulate host cellular growth in keratinocytes. IMPORTANCE HPVs are causative agents in human cancers and are responsible for around of 5% of all cancers. A better understanding of the viral life cycle in keratinocytes will facilitate the development of novel therapeutics to combat HPV-positive cancers. Here, we present a unique keratinocyte model to identify host proteins that specifically interact with HPV16. Using this system, we report that a cellular gene, SAMHD1, is regulated by HPV16 at the RNA and protein levels in keratinocytes. Elimination of SAMHD1 from these cells using CRISPR/Cas9 editing promotes enhanced cellular proliferation by HPV16 in keratinocytes and elevated viral replication but not in keratinocytes that do not have HPV16. Our study demonstrates a specific intricate interplay between HPV16 and SAMHD1 during the viral life cycle and establishes a unique model system to assist exploring host factors critical for HPV pathogenesis.

scholarly journals Prevalence and Subtype Distribution of High-Risk Human Papillomavirus Among Women Presenting for Cervical Cancer Screening at Karanda Mission Hospital

2020 ◽  
pp. 1276-1281 ◽  
Author(s):  
Paul Thistle ◽  
Rabea Parpia ◽  
Debanjan Pain ◽  
Hang Lee ◽  
Justen Manasa ◽  
...  
Keyword(s):  
Cervical Cancer ◽  
Human Papillomavirus ◽  
Cancer Screening ◽  
High Risk ◽  
Cervical Cancer Screening ◽  
Screening Program ◽  
Large Fraction ◽  
Human Papillomaviruses ◽  
Mission Hospital ◽  
Dna Types

PURPOSE High-risk human papillomaviruses (hrHPV) are the primary cause of cervical cancer. Human papillomavirus (HPV) vaccination is expected to prevent cervical cancers caused by the HPV types included in vaccines and possibly by cross-protection from other types. This study sought to determine the hrHPV type distribution in women at a rural Zimbabwe hospital. METHODS We implemented a cross-sectional study at the Karanda Mission Hospital. Using the Visual Inspection with Acetic Acid Cervicography technique, clinicians collected cervical swabs from 400 women presenting for screening for cervical cancer. Samples were initially analyzed by Cepheid GeneXpert; candidate hrHPV genotypes were further characterized using the Anyplex II HPV28 Detection Kit. RESULTS Twenty-one percent of the 400 women were positive for a high-risk genotype when using the GeneXpert analyzer; 17% were positive when using the multiplex analysis. Almost two thirds of the hrHPV women had a single DNA type identified, whereas one third had multiple genotypes, ranging from 2 to 5. hrHPV was observed more frequently in HIV-positive than in HIV-negative women (27% v 15%). Of the 113 isolates obtained, 77% were hrHPV genotypes not included in the bivalent or quadrivalent vaccines, and 47% represented DNA types not covered in the nonavalent vaccine. Forty-seven percent of the women with hrHPV harbored a single genotype that was not covered by the nonavalent vaccine. CONCLUSION A large fraction of hrHPV isolates from women participating in a cervical cancer screening program in northern Zimbabwe are DNA types not covered by the bivalent, quadrivalent, or nonavalent vaccines. These findings suggest the importance of characterizing the hrHPV DNA types isolated from cervical neoplasia in this population and determining whether cross-immunization against these genotypes develops after administration of the vaccines in current use.

scholarly journals DNA Methylation Changes in Human Papillomavirus-Driven Head and Neck Cancers

Cells ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 1359 ◽  
Author(s):  
Chameera Ekanayake Weeramange ◽  
Kai Dun Tang ◽  
Sarju Vasani ◽  
Julian Langton-Lockton ◽  
Liz Kenny ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Human Papillomavirus ◽  
Head And Neck ◽  
Dna Methyltransferase ◽  
Long Control Region ◽  
Cancer Types ◽  
E6 And E7 ◽  
Hpv Oncoproteins ◽  
Cellular Dna ◽  
Methylation Patterns

Disruption of DNA methylation patterns is one of the hallmarks of cancer. Similar to other cancer types, human papillomavirus (HPV)-driven head and neck cancer (HNC) also reveals alterations in its methylation profile. The intrinsic ability of HPV oncoproteins E6 and E7 to interfere with DNA methyltransferase activity contributes to these methylation changes. There are many genes that have been reported to be differentially methylated in HPV-driven HNC. Some of these genes are involved in major cellular pathways, indicating that DNA methylation, at least in certain instances, may contribute to the development and progression of HPV-driven HNC. Furthermore, the HPV genome itself becomes a target of the cellular DNA methylation machinery. Some of these methylation changes appearing in the viral long control region (LCR) may contribute to uncontrolled oncoprotein expression, leading to carcinogenesis. Consistent with these observations, demethylation therapy appears to have significant effects on HPV-driven HNC. This review article comprehensively summarizes DNA methylation changes and their diagnostic and therapeutic indications in HPV-driven HNC.

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