University of Cambridge
Department of Pathology
John Doorbar is Professor of Viral Pathogenesis in the Department of Pathology at the University of Cambridge, having worked previously at the National Institute for Medical Research in London. He obtained his PhD in Cancer Studies at Birmingham, and his first degree in Genetics & Microbiology at the University of Leeds. He has devoted much of his career to understanding how the human papillomavirus life cycle is organised, and how interactions between the virus and the infected epithelial cells drive the development of neoplasia and cancer. His current research addresses the mechanisms of lesion formation and regression, and the way that human papillomaviruses modulate epithelial homeostasis to facilitate virus persistence. His research group is focusing on the biology of the cervical transformation zone, and the molecular and cellular processes that make this particular epithelial site vulnerable to HPV infection and neoplastic progression.

Moderator of 4 Sessions

Session Type
Special Satellite Symposium
Date
Sun, Apr 16, 2023
Session Time
07:00 AM - 08:05 AM
Room
On Demand Content – watch anytime
Session Description
Objectives; How to eliminate cervico-vaginal cancer in Japan. Session time; 60 mins. Cervical cancer incidence has been rising since the late 1990s to 11 per 100,000 women, and this rise is particularly prominent in women of reproductive age in Japan. While the recent resumption of the active recommendations of HPV vaccine was a critical step forward, there are still unresolved issues and fundamental challenges in monitoring and achieving the global targets. Dr. Rei Haruyama aims to synthesize these issues and provide considerations for enhancement of cervical cancer control in Japan. Dr. Tomomi Nakahara investigated mechanisms for HPV genome replication and maintenance in HPV life cycle. She identified that HPV genome can be maintained in an E1, a viral DNA helicase, independent manner in basal cells of the stratified epithelium by using a tissue culture model to recapitulate HPV life cycle. She will discuss how these findings could be exploited to develop a new therapy to eliminate the viral persistence and prevent cervical cancer. Dr. Kaori Okayama developed a system to identify 39 HPV types including all high-risk (HR), all possibly high-risk (pHR), and some low-risk (LR) HPV types using molecular mapping or a single cell sorting procedure. HPV genotyping using cervical or vaginal cell samples reveals that HR-HPV types are predominantly in the uterine cervix, LR-types in the vagina, and pHR types equally in both sites. Tissue tropisms in different HPV-risk types may help us to understand HPV carcinogenesis in the cervico-vagina, providing useful information in clinico-pathological diagnosis.
Session Type
Interdisciplinary Workshop
Date
Mon, Apr 17, 2023
Session Time
10:00 AM - 11:30 AM
Room
Ballroom C
Session Type
Basic Science
Date
Mon, Apr 17, 2023
Session Time
02:00 PM - 03:30 PM
Room
207B
Session Type
Basic Science
Date
Thu, Apr 20, 2023
Session Time
10:30 AM - 12:00 PM
Room
207B

Presenter of 3 Presentations

CERVIX AND CERVICAL CANCER

Session Type
Basic Science
Date
Mon, Apr 17, 2023
Session Time
02:00 PM - 03:30 PM
Room
207B
Presentation Type
ONSITE
Lecture Time
02:03 PM - 02:24 PM

BASIC MECHANISMS OF HPV CARCINOGENESIS

Session Type
Interdisciplinary Workshop
Date
Mon, Apr 17, 2023
Session Time
08:00 AM - 09:30 AM
Room
Ballroom C
Presentation Type
ONSITE
Lecture Time
08:54 AM - 09:11 AM

E6AP IS IMPORTANT FOR HPV E6’S ROLE IN REGULATING EPITHELIAL HOMEOSTASIS AND ITS LOSS IMPAIRS KERATINOCYTE COMMITMENT TO DIFFERENTIATION

Session Type
Basic Science
Date
Thu, Apr 20, 2023
Session Time
10:30 AM - 12:00 PM
Room
207B
Presentation Type
ONSITE
Lecture Time
11:30 AM - 11:40 AM

Abstract

Introduction

E6AP is a conserved binding partner and cellular target of all Alpha group HPV E6 proteins, but its precise role in modulating keratinocyte phenotype and associated signalling pathways have not been defined.

Methods

NIKS and primary foreskin keratinocytes transduced with the FUCCI cell cycle reporter, were used in combination with EGFP/mCherry cell-cell competition assays to model the epithelial basal layer. Digital imaging approaches and molecular analysis were used complement these studies.

Results

The homeostasis functions of E6 are dependent on E6AP and NHERF1, with both proteins involved in regulating basal cell density and differentiation. Interestingly, both 16 and 11 E6 required E6AP and NHERF1 binding to promote YAP nuclear localisation and YAP-reponsive gene activation to stimulate cell proliferation. Deletion of E6AP delayed the onset of differentiation, as determined by K10 immunofluorescence and PCR/RNAseq analysis. Furthermore, cells lacking E6AP resembled those expressing E6, and showed activation of the same YAP-responsive genes. NHERF1 downregulation was also common to both E6-expressing and E6AP -/- cells, suggesting that E6 and E6AP differentially regulate NHERF1 level transcriptionally and at the protein level. NHERF1 is known to interact with signalling proteins including PTEN, YAP1, beta-catenin and frizzled. Knock down NHERF1 in NIKS cells, led to YAP nuclear localisation and the activation of downstream genes. Importantly, immunostaining studies on clinical material revealed that both E6AP and NHERF1 are clearly detectable in the human epithelial basal layer, and that their abundance decreases significantly following HPV infection.

Conclusions

E6AP-/- keratinocytes phenotypically resemble E6-expressing cells, with E6AP impairing keratinocyte differentiation commitment, which is critical for HPV E6’s ability to regulate epithelial homeostasis. We suspect that E6 modulates homeostasis by inhibiting E6AP function, which impairs NHERF1 function to activate the YAP pathway, and that this accentuates the established impact of E6 on commitment to differentiation is mediated through p53.

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