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In vitro progression of human papillomavirus 16 episome-associated cervical neoplasia displays fundamental similarities to integrant-associated carcinogenesis.

ABSTRACT: An important event in the development of cervical squamous cell carcinoma (SCC) is deregulated expression of high-risk human papillomavirus (HR-HPV) oncogenes, most commonly related to viral integration into host DNA. Mechanisms of development of the approximately 15% of SCCs that contain extrachromosomal (episomal) HR-HPV are poorly understood due to limited longitudinal data. We therefore used the W12 model to study mechanisms of cervical carcinogenesis associated with episomal HPV16. In vitro progression of W12 normally occurs through selection of cells containing integrated HPV16. However, in one long-term culture, keratinocytes developed a selective growth advantage and invasive phenotype while retaining HPV16 episomes at increased copy number in the absence of transcriptionally active integrants. Longitudinal investigations revealed similarities between the episome- and integrant-associated routes of neoplastic progression. Most notable were dynamic changes in viral early gene expression in episome-retaining cells, consistent with continually changing selective pressures. An early increase in viral transcription preceded elevated episome copy number and was followed by a reduction to near baseline after the development of invasiveness. Episomal transcriptional deregulation did not require selection of a specific sequence variant of the HPV16 upstream regulatory region, although increased levels of acetylated histone H4 around the late promoter implicated a role for altered chromatin structure. Interestingly, invasive episome-retaining cells showed high levels of HPV16 E2/E6 proteins (despite decreased transcript levels) and reduced expression of IFN-stimulated genes, adaptations that support viral persistence and cell survival. Our findings suggest a unified working model for events important in cervical neoplastic progression regardless of HR-HPV physical state.

SUBMITTER: Gray E

PROVIDER: S-EPMC2872760 | biostudies-literature | 2010 May

REPOSITORIES: biostudies-literature

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In vitro progression of human papillomavirus 16 episome-associated cervical neoplasia displays fundamental similarities to integrant-associated carcinogenesis.

Gray Elizabeth E Pett Mark R MR Ward Dawn D Winder David M DM Stanley Margaret A MA Roberts Ian I Scarpini Cinzia G CG Coleman Nicholas N

Cancer research 20100504 10

An important event in the development of cervical squamous cell carcinoma (SCC) is deregulated expression of high-risk human papillomavirus (HR-HPV) oncogenes, most commonly related to viral integration into host DNA. Mechanisms of development of the approximately 15% of SCCs that contain extrachromosomal (episomal) HR-HPV are poorly understood due to limited longitudinal data. We therefore used the W12 model to study mechanisms of cervical carcinogenesis associated with episomal HPV16. In vitro ...[more]

PMID: 20442284

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Project description:BackgroundHuman papillomavirus (HPV) types 16 and 18 are the high-risk, sexually transmitted infectious causes of most cervical intraepithelial neoplasias (CIN) or cancers. While efficacious vaccines to reduce the sexual acquisition of these high-risk HPVs have recently been introduced, no virus-targeted therapies exist for those already exposed and infected. Considering the oncogenic role of the transforming (E6 and E7) genes of high-risk HPVs in the slow pathogenesis of cervical cancer, we hypothesize that timely disruption or abolition of HPV genome expression within pre-cancerous lesions identified at screening may reverse neoplasia. We aimed to derive model zinc finger nucleases (ZFNs) for mutagenesis of the genomes of two high-risk HPV (types 16 & 18).Methods and resultsUsing ZiFiT software and the complete genomes of HPV types16 and 18, we computationally generated the consensus amino acid sequences of the DNA-binding domains (F1, F2, & F3) of (i) 296 & 327 contextually unpaired (or single) three zinc-finger arrays (sZFAs) and (ii) 9 & 13 contextually paired (left and right) three- zinc-finger arrays (pZFAs) that bind genomic DNA of HPV-types 16 and 18 respectively, inclusive of the E7 gene (s/pZFAHpV/E7). In the absence of contextually paired three-zinc-finger arrays (pZFAs) that bind DNA corresponding to the genomic context of the E6 gene of either HPV type, we derived the DNA binding domains of another set of 9 & 14 contextually unpaired E6 gene-binding ZFAs (sZFAE6) to aid the future quest for paired ZFAs to target E6 gene sequences in both HPV types studied (pZFAE6). This paper presents models for (i) synthesis of hybrid ZFNs that cleave within the genomic DNA of either HPV type, by linking the gene sequences of the DNA-cleavage domain of the FokI endonuclease FN to the gene sequences of a member of the paired-HPV-binding ZFAs (pZFAHpV/E7 + FN), and (ii) delivery of the same into precancerous lesions using HPV-derived viral plasmids or vectors.ConclusionsWith further optimization, these model ZFNs offer the opportunity to induce target-mutagenesis and gene-therapeutic reversal of cervical neoplasia associated with HPV types 16 & 18.

Project description:HPV16 accounts for 50-70% of cervical cancer cases worldwide. Characterization of HPV16 variants previously indicated that they differ in risks for viral persistence, progression to cervical precancer and malignant cancer. The aim of this study was to examine the association of severity of disease with HPV16 variants identified in specimens (n = 281) obtained from a Cervical Pathology and Colposcopy outpatient clinic in the University Hospital of Espírito Santo State, Southeastern Brazil, from April 2010 to November 2011. All cytologic and histologic diagnoses were determined prior to definitive treatment. The DNA was isolated using QIAamp DNA Mini Kit and HPV was detected by amplification with PGMY09/11 primers and positive samples were genotyped by RFLP analyses and reverse line blot. The genomes of the HPV16 positive samples were sequenced, from which variant lineages were determined. Chi2 statistics was performed to test the association of HPV16 variants between case and control groups. The prevalence of HR-HPV types in <CIN1, CIN2 and CIN3+ were 33.7%, 84.4% and 91.6%, respectively. Thirty-eight of 49 (78%) HPV16 positive samples yielded HPV16 sequence information; of which, 32 complete genomes were sequenced and an additional 6 samples were partially sequenced. Phylogenetic analysis and patterns of variations identified 65.8% (n = 25) as HPV16 European (E) and 34.2% (n = 13) as non-European (NE) variants. Classification of disease into CIN3+ vs. <CIN3 indicated that NE types were associated with high-grade disease with an OR = 4.6 (1.07-20.2, p = 0.05). The association of HPV16 NE variants with an increased risk of CIN3+ is consistent with an HPV16 genetically determined enhanced oncogenicity. The prevalence of genetic variants of HPV16 is distributed across different geographical areas and with recent population admixture, only empiric data will provide information on the highest risk HPV16 variants within a given population.

Project description:OBJECTIVE:To calculate pooled risk estimates for combinations of cytology result, human papillomavirus (HPV) 16/18 genotype and colposcopy impression to provide a basis for risk-stratified colposcopy and biopsy practice. DATA SOURCE:A PubMed search was conducted on June 1, 2016, and a ClinicalTrials.gov search was conducted on June 9, 2018, using key words such as "uterine cervical neoplasms," "cervical cancer," "mass screening," "early detection of cancer," and "colposcopy." METHODS OF STUDY SELECTION:Eligible studies must have included colposcopic impression and either cytology results or HPV 16/18 partial genotype results as well as a histologic biopsy diagnosis from adult women. Manuscripts were reviewed for the following: cytology, HPV status, and colposcopy impression as well as age, number of women, and number of cervical intraepithelial neoplasia (CIN) 2, CIN 3, and cancer cases. Strata were defined by the various combinations of cytology, genotype, and colposcopic impression. TABULATION, INTEGRATION, AND RESULTS:Of 340 abstracts identified, nine were eligible for inclusion. Data were also obtained from three unpublished studies, two of which have since been published. We calculated the risk of CIN 2 or worse and CIN 3 or worse based on cytology, colposcopy, and HPV 16/18 test results. We found similar risk patterns across studies in the lowest risk groups such that risk estimates were similar despite different referral populations and study designs. Women with a normal colposcopy impression (no acetowhitening), less than high-grade squamous intraepithelial lesion cytology, and HPV 16/18-negative were at low risk of prevalent precancer. Women with at least two of the following: high-grade squamous intraepithelial lesion cytology, HPV16- or HPV18-positive, and high-grade colposcopic impression were at highest risk of prevalent precancer. CONCLUSION:Our results support a risk-based approach to colposcopy and biopsy with modifications of practice at the lowest and highest risk levels.

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In vitro progression of human papillomavirus 16 episome-associated cervical neoplasia displays fundamental similarities to integrant-associated carcinogenesis.

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In vitro progression of human papillomavirus 16 episome-associated cervical neoplasia displays fundamental similarities to integrant-associated carcinogenesis.

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