Rare human papillomavirus 16 E6 variants reveal significant oncogenic potential

The aim of this study was to determine whether low prevalence human papillomavirus (HPV) 16 E6 variants differ from high prevalence types in their functional abilities. We evaluated functions relevant to carcinogenesis for the rarely-detected European variants R8Q, R10G and R48W as compared to the commonly detected L83V. Human immortalized keratinocytes (NIKS) stably transduced with the E6 variants were used in most functional assays. Low and high prevalence E6 variants displayed similar abilities in abrogation of growth arrest and inhibition of p53 elevation induced by actinomycin D. Differences were detected in the abilities to dysregulate stratification and differentiation of NIKS in organotypic raft cultures, modulate detachment induced apoptosis (anoikis) and hyperactivate Wnt signaling. No distinctive phenotype could be assigned to include all rare variants. Like L83V, raft cultures derived from variants R10G and R48W similarly induced hyperplasia and aberrantly expressed keratin 5 in the suprabasal compartment with significantly lower expression of keratin 10. Unlike L83V, both variants, and particularly R48W, induced increased levels of anoikis upon suspension in semisolid medium. R8Q induced a unique phenotype characterized by thin organotypic raft cultures, low expression of keratin 10, and high expression of keratins 5 and 14 throughout all raft layers. Interestingly, in a reporter based assay R8Q exhibited a higher ability to augment TCF/β-catenin transcription. The data suggests that differences in E6 variant prevalence in cervical carcinoma may not be related to the carcinogenic potential of the E6 protein

Toll-Like Receptor Transcriptome in the HPV-Positive Cervical Cancer Microenvironment

The human papillomavirus (HPV) directly infects cervical keratinocytes and interferes with TLR signalling. To shed light on the effect of HPV on upstream receptors, we evaluated TLRs 1–9 gene expression in HPV-negative normal and HPV-positive pre-malignant and malignant ex vivo cervical tissue. Quantitative real-time polymerase chain reaction was performed separately for epithelial and stromal tissue compartments. Differences in gene expression were analyzed by the Jonckheere-Terpstra trend test or the Student's t-test for pairwise comparison. Laser capture microdissection revealed an increase in TLR3 and a decrease in TLR1 mRNA levels in dysplastic and carcinoma epithelium, respectively. In the stroma, a trend of increasing TLR 1, 2, 5, 6, and 9 mRNA levels with disease severity was found. These findings implicate the involvement of TLR3 and TLR1 in early and late cervical carcinogenesis, respectively, suggesting that stromal upregulation of TLRs may play a role in cervical disease progression

Colonial legacy and the experience of First Nations women in cervical cancer screening: a Canadian multi-community study

This is an Accepted Manuscript of an article published by Taylor & Francis in Critical Public health on July 22, 2015, available online: http://dx.doi.org/10.1080/09581596.2015.1067671Regular Papanicolaou (Pap) screening has dramatically reduced cervical cancer incidence in Canada since the 1950s. However, Indigenous women’s rates of cervical cancer remain disproportionately high, a factor which is not acknowledged in national media or in educational materials reporting Canada’s new cervical cancer screening guidelines. Here, we present findings from a cervical cancer screening initiative in Northwestern Ontario. Based on participatory action research, we worked with 10 First Nations communities in the Robinson Superior Treaty area to increase awareness of cervical cancer risk, develop culturally sensitive tools for screening and education and test the efficacy of human papillomavirus (HPV) self-sampling as an alternative to Pap cytology. We conducted 16 interviews with health care professionals and 9 focus groups with 69 women from the communities. A central theme for both health care providers (HCPs) and community members was the colonial legacy and its influence on women’s experiences of cervical cancer screening. This was evidenced by a strong sense of body shyness, including shame related to sexuality and sexually transmitted infections, concerns about confidentiality in clinical encounters and distrust or caution around HCPs. Reaffirming women’s traditional caregiving and educational roles, enhancing mother and daughter communication, improving cultural sensitivity in health care and education and adoption of HPV self-sampling to increase women’s privacy and control of the cervical cancer screening experience were endorsed. We argue that education and screening initiatives must reflect the cultural preferences of Indigenous women, empowering them to take control of their experiences of health and body in cervical cancer screening

Functional variants of human papillomavirus type 16 demonstrate host genome integration and transcriptional alterations corresponding to their unique cancer epidemiology

BACKGROUND: 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. RESULTS: 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. CONCLUSIONS: 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. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12864-016-3203-3) contains supplementary material, which is available to authorized users

Teaching tools to engage Anishinaabek First Nations women in cervical cancer screening: Report of an educational workshop

This is the post-print version of the paper that was accepted for publication in Health education journal. The publisher's version is available at http://dx.doi.org/10.1177/0017896915580446Objective: To explore educational strategies for engaging First Nations women in Canada to attend cervical cancer screening. Design: Within a participatory action research framework, semi-structured interviews with health-care providers in First Nations communities revealed that education about the value of screening is perceived as being a key factor to promote cervical cancer screening. Setting: To obtain feedback from workshop informants, a 1-day educational workshop was held to identify appropriate educational intervention strategies, which would be applied in a forthcoming randomised controlled cervical screening trial. Methods: Common discussion and discussion groups, which were facilitated by a First Nations workshop moderator and a note taker. Results: This workshop helped to strengthen the ethical space dialogue with the First Nations communities with whom the study team had established research partnerships. The workshop atmosphere was relaxed and the invited informants decided that an educational health promotion event for community women needed to be held prior to inviting them to the cervical screening trial. Such an event would provide an opportunity to communicate the importance of attending regular cervical screening allowing women to make informed decisions about screening participation. Complementary promotional items, including an eye-catching pamphlet and storytelling, were also suggested. Conclusion: The key messages from the events and promotional items can help to de-stigmatise women who develop a type of cancer that is caused by a sexually transmitted virus that affects both men and women. Developing and implementing positive health education that respectfully depicts female bodies, sexuality and health behaviours through a First Nations lens is strongly warranted

Quercetin elevates p27Kip1 and arrests both primary and HPV16 E6/E7 transformed human keratinocytes in G1

Our previous work with primary bovine fibroblasts demonstrated that quercetin, a potent mutagen found in high levels in bracken fern (Pteridium aquilinum), arrested cells in G1 and G2/M, in correlation with p53 activation. The expression of bovine papillomavirus type 4 (BPV-4) E7 overcame this arrest and lead to the development of tumorigenic cells lines (Beniston et al., 2001). Given the possible link between papillomavirus infection, bracken fern in the diet and cancer of the upper gastrointestinal (GI) tract in humans, we investigated whether a similar situation would occur in human cells transformed by human papillomavirus type 16 (HPV-16) oncoproteins. Quercetin arrested primary human foreskin keratinocytes in G1. Arrest was linked to an elevation of the cyclin-dependent kinase inhibitor (cdki) p27Kip1. Expression of the HPV16 E6 and E7 oncoproteins in transformed cells failed to abrogate cell cycle arrest. G1 arrest in the transformed cells was also linked to an increase of p27Kip1 with a concomitant reduction of cyclin E-associated kinase activity. This elevation of p27Kip1 was due not only to increased protein half-life, but also to increased mRNA transcription

The human papillomavirus 16 European-T350G E6 variant can immortalize but not transform keratinocytes in the absence of E7

AbstractHuman papillomavirus type 16 is commonly implicated in HPV-related cancers. However, only a small number of infected individuals progress to this stage. Epidemiological evidence demonstrated that oncogenic risk is population-specific and variations within the viral oncogene, E6, have been suggested to play a role in these findings. Of focus in this study is the European-T350G variant, which is characterized by an L>V amino acid substitution at residue 83 of the prototype E6 protein. To elucidate the functional effects of this polymorphism, we followed keratinocytes transduced with E-T350G E6 for over 60 passages and compared them to keratinocytes transduced, in parallel, with prototype or Asian-American (Q14H/L83V/H78Y) E6. We found that although E-T350G E6 immortalized transduced keratinocytes in the absence of E7, these cells were not fully transformed. We also found that E-T350G down-regulated E-cadherin compared to the other variants, providing a possible link between its population-based oncogenicity and host genetic variations