ABSTRACT: Comprehensive characterization of human papillomavirus methylation and integration sites in cervical intraepithelial neoplasia and carcinoma by targeted, deep next‐generation sequencing
Project description:Integration of human papillomavirus (HPV) DNA into the host genome is a critical aetiological event in the progression from normal cervix to intraepithelial neoplasm, and finally to invasive cervical cancer. In this study, we want to know how HPV DNA physical status relates to treatment outcome for cervical carcinomas.
Project description:Integration of human papillomavirus (HPV) DNA into the host genome is a critical aetiological event in the progression from normal cervix to intraepithelial neoplasm, and finally to invasive cervical cancer. In this study, we want to know how HPV DNA physical status relates to treatment outcome for cervical carcinomas. Cervical cancer samples were compared with normal sample. And also, we divided 39 cervical cancer patients into four groups according to HPV DNA physical status and investigated differentially expressed gene profiles in these groups using Agilent two-color experiment.
Project description:Human papillomavirus (HPV) integration is a critical step in cervical cancer development, while the oncogenic mechanism in genome-wide transcriptional level is still poorly understood. In this study, we employed integrative analysis on multi-omics data of cervical cancer cell lines. Through HPV integration detection, super enhancer (SE) identification, SE-associated gene expression and extrachromosomal DNA (ecDNA) investigation, we aimed to explore the genome-wide transcriptional influence of HPV integration. We identified 5 high-ranking cellular super enhancers generated by HPV integration (the HPV breakpoint induced cellular super enhancers, BP-cSE), leading to intra-chromosomal and inter-chromosomal regulations of chromosomal genes. The pathway analysis showed the dysregulated chromosomal genes were correlated to cervical cancer associated pathways. Importantly, we demonstrated that BP-cSE existed in the HPV-host ecDNA, explaining above transcription alterations. Our results suggest that HPV integration generates cellular super enhancers and functions as ecDNA to regulate unconstraint transcription, expanding the tumorigenic mechanism of HPV integration and providing insights of developing new diagnostic and therapeutic strategies.
Project description:Epigenetic alterations are essential in the development of cancers, while epigenome-wide exploration in cervical cancer has been limited. In this epigenome-wide association study (EWAS) we explore differential DNA methylation signatures associated with CIN (cervical intraepithelial neoplasia) grade 3 and cervical cancer, to better understand potential drivers and biomarkers of cervical carcinogenesis. 247 women were recruited between 2014-2020 (N=119 benign, N=74 CIN3/CGIN (cervical glandular intraepithelial neoplasia) and N=54 cancer). Methylation signatures were obtained from exfoliated cervical cells and sequenced using the Illumina 850k array. Logistic regression and conditional analyses were used to test for independent associations between Cytosine-phosphate-Guanine (CpG) sites and case-control status, with adjustment for batch, chip, age, and human papillomavirus (HPV) status. 409 CpG sites were strongly associated with CIN3/cancer (P-value <5x10-8). Following conditional analysis, two CpG sites located in PAX1 (cg16767801) and NREP-AS1 genes (cg23642047) were independently associated with case status; yielding an area under the curve (AUC) of 0.92 (AUC=0.97 for invasive disease). In a validation dataset (CIN3 only) PAX1/NREP-AS1 yielded a combined AUC of 0.77. Methylation markers offer promise for use in cervical screening particularly as triage tests and self-sampling. We have identified a novel combined methylation marker that offers a high accuracy for detection of CIN3 or worse.
Project description:Cervical cancer results from the accumulation of (epi)genetic aberrations following persistent infection with high-risk human papillomavirus (HPV). In order to define genetic aberrations associated with cervical carcinogenesis, chromosomal profiles of high-grade cervical intraepithelial neoplasia (CIN) were generated. Common aberrations usually encompass large genomic regions and contain numerous genes, hampering identification of actual driver genes. Consequently, direct evidence of chromosomal alterations actively contributing to cervical carcinogenesis has been lacking so far. By analyzing 60 high-grade CIN with high resolution arrayCGH we identified focal chromosomal aberrations that each harbour only one or a few genes. In total 74 focal aberrations were identified encoding 305 genes. Analysis of genes located within these focal aberrations, using two independent expression microarray datasets, revealed concurrent altered expression in high-grade CIN and/or cervical carcinomas compared to normal cervical samples for 8 genes: ATP13A3, HES1, OPA1, HRASLS, EYA2, ZMYND8, APOBEC2 and NCR2. Gene silencing of EYA2, located within a focal gain at 20q13, significantly reduced viability and migratory capacity of HPV16-transformed keratinocytes. Interestingly, for hsa-miR-375, located within the most frequently identified focal loss at 2q35, a direct correlation between a (focal) loss and significantly reduced expression was found. Down-regulation of hsa-miR-375 expression during cervical carcinogenesis was confirmed in a second independent series of cervical tissues. Moreover, ectopic expression of hsa-miR-375 in 2 cervical carcinoma cell lines reduced cellular viability. In conclusion, our data provide a proof of concept that chromosomal aberrations are actively contributing to HPV-induced carcinogenesis and identify EYA2 and hsa-mir-375 as oncogene and tumor suppressor gene, respectively. DNA from microdissected tissues: 60 samples total. 11 high-grade CIN, <5yr preceding hrHPV infection, 43 high-grade CIN >5yr preceding hrHPV infection, 6 CIN3 adjacent to SCC
Project description:Human papillomavirus (HPV) genome integration into the host genome, blocking E2 expression and leading to overexpression of E6 and E7 viral oncogenes, is considered a major step in cervical cancer development. In high-risk HPVs, E6 and E7 oncogenes are expressed as a bicistronic pre-mRNA, with alternative splicing producing the ultimate mRNAs required for E6 and E7 translation. Given the number of alternative donor and acceptor splicing sites, ten E6/E7 different alternative transcripts might be formed for HPV16 and three for HPV18, although only six isoforms have been previously reported for HPV16. In the present work, we employ high-throughput sequencing of invasive cervical cancer transcriptome (RNA-Seq) to characterize the expression of the HPV genome in 24 invasive cervical cancers associated with HPV16 and HPV18 single infections. Based on high-resolution transcriptional maps, we herein report three viral gene expression patterns which might be associated with the presence of the viral genome in episomal and/or integrated stages. Alternative mRNAs splicing isoforms coding for E6 and E7 oncoproteins were characterized and quantified, and two novel isoforms were identified. Three major isoforms (E6*I, E6*II, and E6+E7) were detected for HPV16 and two for HPV18 (E6*I and E6+E7). Minor transcript isoforms, including the novel ones, were very rare in some tumor samples or were not detected. Our data suggested that minor transcript isoforms of E6/E7 do not play a relevant role in cervical cancer.
Project description:Oncogenic human papillomavirus (HPV) genomes are often integrated into host chromosomes in HPV-associated cancers. HPV genomes are integrated either as a single copy, or as tandem repeats of viral DNA interspersed with, or without, host DNA. Integration occurs frequently in common fragile sites susceptible to tandem repeat formation, and the flanking or interspersed host DNA often contains transcriptional enhancer elements. When co-amplified with the viral genome, these enhancers can form super-enhancer-like elements that drive high viral oncogene expression. Here, we compiled highly curated datasets of HPV integration sites in cervical (CESC) and head and neck squamous cell carcinoma (HNSCC) cancers and assessed the number of breakpoints, viral transcriptional activity, and host genome copy number at each insertion site. Tumors frequently contained multiple distinct HPV integration sites, but often only one “driver” site that expressed viral RNA. Since common fragile sites and active enhancer elements are cell-type specific, we mapped these regions in cervical cell lines using FANCD2 and Brd4/H3K27ac ChIP-seq, respectively. Large enhancer clusters, or super-enhancers, were also defined using the Brd4/H3K27ac ChIP-seq dataset. HPV integration breakpoints were enriched at both FANCD2-associated fragile sites, and enhancer-rich regions, and frequently showed adjacent focal DNA amplification in CESC samples. We identified recurrent integration “hotspots” that were enriched for super-enhancers, some of which function as regulatory hubs for cell-identity genes. We propose that during persistent infection, extrachromosomal HPV minichromosomes associate with these transcriptional epicenters, and accidental integration could promote viral oncogene expression and carcinogenesis.
Project description:Cervical cancer results from the accumulation of (epi)genetic aberrations following persistent infection with high-risk human papillomavirus (HPV). In order to define genetic aberrations associated with cervical carcinogenesis, chromosomal profiles of high-grade cervical intraepithelial neoplasia (CIN) were generated. Common aberrations usually encompass large genomic regions and contain numerous genes, hampering identification of actual driver genes. Consequently, direct evidence of chromosomal alterations actively contributing to cervical carcinogenesis has been lacking so far. By analyzing 60 high-grade CIN with high resolution arrayCGH we identified focal chromosomal aberrations that each harbour only one or a few genes. In total 74 focal aberrations were identified encoding 305 genes. Analysis of genes located within these focal aberrations, using two independent expression microarray datasets, revealed concurrent altered expression in high-grade CIN and/or cervical carcinomas compared to normal cervical samples for 8 genes: ATP13A3, HES1, OPA1, HRASLS, EYA2, ZMYND8, APOBEC2 and NCR2. Gene silencing of EYA2, located within a focal gain at 20q13, significantly reduced viability and migratory capacity of HPV16-transformed keratinocytes. Interestingly, for hsa-miR-375, located within the most frequently identified focal loss at 2q35, a direct correlation between a (focal) loss and significantly reduced expression was found. Down-regulation of hsa-miR-375 expression during cervical carcinogenesis was confirmed in a second independent series of cervical tissues. Moreover, ectopic expression of hsa-miR-375 in 2 cervical carcinoma cell lines reduced cellular viability. In conclusion, our data provide a proof of concept that chromosomal aberrations are actively contributing to HPV-induced carcinogenesis and identify EYA2 and hsa-mir-375 as oncogene and tumor suppressor gene, respectively.
Project description:The Illumina Infinium 27k Human DNA methylation Beadchip v1.2 was used to obtain DNA methylation profiles across approximately 27,000 CpGs in smear cells from the uterine cervix (liquid based cytology samples), obtained from 48 women. All women tested positive for the human papilloma virus (HPV+). Of the 48 samples, 24 were cytologically normal while the other 24 exhibited morphological transformation (cervical intraepithelial neoplasia of grade 2 or higher - CIN2+).