Functional variants of human papillomavirus type 16 demonstrate host genome integration and transcriptional alterations corresponding to their unique cancer epidemiology.
Human papillomaviruses (HPVs) are a worldwide burden as they are a widespread group of tumour viruses in humans. Having a tropism for mucosal tissues, high-risk HPVs are detected in nearly all cervical cancers. HPV16 is the most common high-risk type but not all women infected with high-risk HPV develop a malignant tumour. Likely relevant, HPV genomes are polymorphic and some HPV16 single nucleotide polymorphisms (SNPs) are under evolutionary constraint instigating variable oncogenicity and immunogenicity in the infected host.



To investigate the tumourigenicity of two common HPV16 variants, we used our recently developed, three-dimensional organotypic model reminiscent of the natural HPV infectious cycle and conducted various "omics" and bioinformatics approaches. Based on epidemiological studies we chose to examine the HPV16 Asian-American (AA) and HPV16 European Prototype (EP) variants. They differ by three non-synonymous SNPs in the transforming and virus-encoded E6 oncogene where AAE6 is classified as a high- and EPE6 as a low-risk variant. Remarkably, the high-risk AAE6 variant genome integrated into the host DNA, while the low-risk EPE6 variant genome remained episomal as evidenced by highly sensitive Capt-HPV sequencing. RNA-seq experiments showed that the truncated form of AAE6, integrated in chromosome 5q32, produced a local gene over-expression and a large variety of viral-human fusion transcripts, including long distance spliced transcripts. In addition, differential enrichment of host cell pathways was observed between both HPV16 E6 variant-containing epithelia. Finally, in the high-risk variant, we detected a molecular signature of host chromosomal instability, a common property of cancer cells.



We show how naturally occurring SNPs in the HPV16 E6 oncogene cause significant changes in the outcome of HPV infections and subsequent viral and host transcriptome alterations prone to drive carcinogenesis. Host genome instability is closely linked to viral integration into the host genome of HPV-infected cells, which is a key phenomenon for malignant cellular transformation and the reason for uncontrolled E6 oncogene expression. In particular, the finding of variant-specific integration potential represents a new paradigm in HPV variant biology.
Probe Development and Biomarker Exploration, Thunder Bay Regional Research Institute, Thunder Bay, Ontario, Canada.|Biotechnology Program, Lakehead University, Thunder Bay, Ontario, Canada.
Robert
R
Jackson
McDonnell Genome Institute, Washington University School of Medicine, St. Louis, MO, USA.
Bruce A
BA
Rosa
NGS platform, Institut Curie, PSL Research University, 26 rue d'Ulm, 75248, Paris, Cedex, France.
Sonia
S
Lameiras
Probe Development and Biomarker Exploration, Thunder Bay Regional Research Institute, Thunder Bay, Ontario, Canada.|Northern Ontario School of Medicine, Lakehead University, Thunder Bay, Ontario, Canada.
Sean
S
Cuninghame
Probe Development and Biomarker Exploration, Thunder Bay Regional Research Institute, Thunder Bay, Ontario, Canada.|Department of Biology, Lakehead University, Thunder Bay, Ontario, Canada.
Josee
J
Bernard
Department of Chemistry, Lakehead University, Thunder Bay, Ontario, Canada.
Wely B
WB
Floriano
McArdle Laboratory for Cancer Research, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA.
Paul F
PF
Lambert
Institut Curie, PSL Research University, Centre National de la Recherche Scientifique UMR3244, Sorbonne Universités, Paris, France.
Alain
A
Nicolas
Probe Development and Biomarker Exploration, Thunder Bay Regional Research Institute, Thunder Bay, Ontario, Canada. zehbei@tbh.net.|Northern Ontario School of Medicine, Lakehead University, Thunder Bay, Ontario, Canada. zehbei@tbh.net.|Department of Biology, Lakehead University, Thunder Bay, Ontario, Canada. zehbei@tbh.net.
Ingeborg
I
Zehbe
D043171:Chromosomal Instability; D054884:Host-Pathogen Interactions / Q000235:genetics*; D052162:Human papillomavirus 16 / Q000235:genetics* / Q000502:physiology*; D006801:Humans; D009369:Neoplasms / Q000453:epidemiology* / Q000235:genetics / Q000821:virology*; D010641:Phenotype; D020641:Polymorphism, Single Nucleotide; D013045:Species Specificity; D014158:Transcription, Genetic; D016662:Virus Integration / Q000235:genetics
E6 oncogene variants; HPV16; Human papillomavirus; Organotypic rafts; Pathogen-host relationship; Transcriptomics; Viral integration