Human Papillomavirus Genomes Associate with Active Host Chromatin during Viral Genome Maintenance [Hi-C]
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE294037 | GEO | 2025/07/07
REPOSITORIES: GEO
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Project description:Human papillomaviruses (HPVs) maintain their genomes as minichromosomes in the nuclei of infected keratinocytes. This study investigates the association of HPV31 genomes with host chromatin using both HiC and 4C-seq chromosome conformation capture techniques. We show that HPV31 genomes preferentially associate with transcriptionally active A compartments of host chromatin, regions of open chromatin defined by ATAC-seq, and super-enhancers defined by Brd4 and H3K27ac ChIP-seq. The viral genome association sites were also highly correlated with genomic loci previously identified as common HPV integration sites in cervical cancers. Recent studies have shown that transcriptionally active sites are prone to dsDNA breaks, and we find a strong correlation among dsBREAK datasets with transcriptionally active and open regions of host chromatin and the HPV31 genome association sites defined in our study. These findings suggest that HPV genomes associate with cellular transcriptional epicenters to maintain active viral gene expression during persistent infection, but also indicate that the susceptibility of these regions to dsDNA breaks could explain their propensity for viral DNA integration in HPV-associated cancers.
2025-07-07 | GSE294064 | GEO
Project description:Human papillomaviruses (HPVs) maintain their genomes as minichromosomes in the nuclei of infected keratinocytes. This study investigates the association of HPV31 genomes with host chromatin using both HiC and 4C-seq chromosome conformation capture techniques. We show that HPV31 genomes preferentially associate with transcriptionally active A compartments of host chromatin, regions of open chromatin defined by ATAC-seq, and super-enhancers defined by Brd4 and H3K27ac ChIP-seq. The viral genome association sites were also highly correlated with genomic loci previously identified as common HPV integration sites in cervical cancers. Recent studies have shown that transcriptionally active sites are prone to dsDNA breaks, and we find a strong correlation among dsBREAK datasets with transcriptionally active and open regions of host chromatin and the HPV31 genome association sites defined in our study. These findings suggest that HPV genomes associate with cellular transcriptional epicenters to maintain active viral gene expression during persistent infection, but also indicate that the susceptibility of these regions to dsDNA breaks could explain their propensity for viral DNA integration in HPV-associated cancers.
2025-07-07 | GSE294036 | GEO
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.
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Project description:Approximately 25% of all head and neck cancers (HNC), and up to 60% of oropharyngeal cancers (OPC) are associated with human papillomavirus (HPV), predominantly HPV16. HPV-associated OPC have better prognosis and a more favorable response to therapy as compared to HPV-negative tumors. Viral oncoproteins are capable of transforming primary human keratinocytes from either genital or oral epithelia in vitro and most likely play the same role in vivo, by disrupting cell-cycle regulatory pathways leading to a genetic progression to ano-genital cancer and OPC. However, the precise mechanisms by which HPV mediates malignant transformation of keratinocytes in the upper digestive tract epithelia are not entirely clear. HPV E7-mediated inactivation of pRb results in overexpression of p16INK4A, which is commonly used as a clinical surrogate marker for HPV positivity/activity. However, high p16INK4A alone has insufficient sensitivity and specificity as a biomarker of HPV positivity in different mucosal sub-sites of HNC. Therefore, increasing emphasis is being placed on the assessment of viral load and E7 oncogene expression, resulting in further classification of HPV positive OPC as HPV-active and HPV-inactive. Differences in risk factors, age of presentation, clinical behavior and gene expression profiles indicate that HPV-positive and HPV-negative tumors develop via different molecular mechanisms and are biologically distinct. This study aimed to compare the gene expression profiles of HPV-active, -inactive and -negative OPC and determine their biological differences. ANALYSIS 1: Three-condition, one-color experiment: HPV-active, HPV-inactive and HPV-negative oropharyngeal tumor samples. Biological replicates: 12 HPV Active tumors, 8 HPV Inactive tumors and 16 HPV Negative tumors.
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Project description:Head and neck cancer (HNC) is the fifth most common malignancy worldwide with an annual mortality rate of 200,000. About 90% of HNC can be classified as head and neck squamous cell carcinomas (HNSCC), of which approximately 75% are attributed to alcohol and tobacco consumption and 25 are associated with human papillomavirus (HPV), predominantly HPV16. HPV-associated OPC have better prognosis and a more favorable response to therapy as compared to HPV-negative tumors. Viral oncoproteins are capable of transforming primary human keratinocytes from either genital or oral epithelia in vitro and most likely play the same role in vivo, by disrupting cell-cycle regulatory pathways leading to a genetic progression to ano-genital cancer and OPC. However, the precise mechanisms by which HPV mediates malignant transformation of keratinocytes in the upper digestive tract epithelia are not entirely clear. HPV E7-mediated inactivation of pRb results in overexpression of p16INK4A, which is commonly used as a clinical surrogate marker for HPV positivity/activity. However, high p16INK4A alone has insufficient sensitivity and specificity as a biomarker of HPV positivity in different mucosal sub-sites of HNC. Therefore, increasing emphasis is being placed on the assessment of viral load and E7 oncogene expression, resulting in further classification of HPV positive OPC as HPV-active and HPV-inactive. Differences in risk factors, age of presentation, clinical behavior and gene expression profiles indicate that HPV-positive and HPV-negative tumors develop via different molecular mechanisms and are biologically distinct. This study aimed to compare the gene expression profiles of HPV-active OPCs and normal benign uvula/tonsil tissues and determine what biological processes and pathways are affected in HPV-active tumors. ANALYSIS 5: Two-condition, one-color experiment: HPV-active oropharyngeal tumor samples and normal benign uvula/tonsil tissues. Biological replicates: 12 HPV active samples and 4 Normal samples.
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Project description:Approximately 25% of all head and neck cancers (HNC), and up to 60% of oropharyngeal cancers (OPC) are associated with human papillomavirus (HPV), predominantly HPV16. HPV-associated OPC have better prognosis and a more favorable response to therapy as compared to HPV-negative tumors. Viral oncoproteins are capable of transforming primary human keratinocytes from either genital or oral epithelia in vitro and most likely play the same role in vivo, by disrupting cell-cycle regulatory pathways leading to a genetic progression to ano-genital cancer and OPC. However, the precise mechanisms by which HPV mediates malignant transformation of keratinocytes in the upper digestive tract epithelia are not entirely clear. HPV E7-mediated inactivation of pRb results in overexpression of p16INK4A, which is commonly used as a clinical surrogate marker for HPV positivity/activity. However, high p16INK4A alone has insufficient sensitivity and specificity as a biomarker of HPV positivity in different mucosal sub-sites of HNC. Therefore, increasing emphasis is being placed on the assessment of viral load and E7 oncogene expression, resulting in further classification of HPV positive OPC as HPV-active and HPV-inactive. Differences in risk factors, age of presentation, clinical behavior and gene expression profiles indicate that HPV-positive and HPV-negative tumors develop via different molecular mechanisms and are biologically distinct. According to some reports, the rate of HPV-associated tumors is much lower in AA patients as compared to EA patients in United States. This study aimed to compare the gene expression profiles of HPV-active, -inactive and -negative OPCs from european american patients, and determine their biological differences. ANALYSIS 3: Three-condition, one-color experiment: HPV-active, HPV-inactive and HPV-negative oropharyngeal tumor samples from european american patients. Biological replicates: 8 HPV Negative Tumors. 4 HPV Inactive Tumors. 11 HPV Active Tumors.
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