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Updated: May 11, 2026
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Use of Interferon-γ Enzyme-linked Immunospot Assay to Characterize Novel T-cell Epitopes of Human Papillomavirus
Published on: March 8, 2012
Expression of HPV16 E5 down-modulates the TGFbeta signaling pathway
Deborah French1, Francesca Belleudi, Maria Vittoria Mauro
1Istitute Pasteur-Fondazione Cenci Bolognetti, Department of Clinical and Molecular Medicine, Sapienza University of Roma, and S. Andrea Hospital, Rome, Italy.
Molecular Cancer
|May 9, 2013
Summary
High-risk human papillomavirus (HR-HPV) E5 protein reduces transforming growth factor beta receptor type II (TGF-BRII) expression, disrupting TGFbeta/Smad signaling. This disruption promotes cervical cancer progression by destabilizing epithelial homeostasis early in infection.
Area of Science:
- Oncology
- Virology
- Molecular Biology
Background:
- High-risk human papillomavirus (HR-HPV) infection, particularly HPV16 and HPV18, is a primary driver of cervical cancer.
- The oncogenic mechanisms of HPV E5 protein are less understood than E6 and E7, but involve growth factor receptor deregulation.
- Transforming growth factor beta (TGFbeta) signaling is critical in epithelial carcinogenesis.
Purpose of the Study:
- To investigate the effect of HPV16 E5 on TGFbeta receptor type II (TGF-BRII) expression.
- To determine if HPV16 E5 modulates the TGFbeta/Smad signaling pathway.
Main Methods:
- Analysis of HPV16 E5 and TGFBRII mRNA expression in cervical lesions (LSIL and HSIL).
- In vitro study using human keratinocytes expressing HPV16 E5 to quantify TGFBRII mRNA and protein.
- Assessment of Smad2 phosphorylation and Smad4 nuclear translocation in E5-expressing cells stimulated with TGFbeta1.
Main Results:
- HPV16 E5 mRNA expression varied in LSIL and decreased in HSIL.
- TGFBRII mRNA levels were inversely related to HPV16 E5 levels in LSIL.
- HPV16 E5 expression led to a dose- and time-dependent decrease in TGFBRII mRNA and protein.
- TGFbeta1-induced Smad2 phosphorylation and Smad4 nuclear translocation were reduced in E5-expressing cells.
Conclusions:
- HPV16 E5 attenuates TGFbeta1/Smad signaling.
- This attenuation destabilizes epithelial homeostasis in early viral infection.
- Loss of TGFbeta signaling by HPV16 E5 is a key mechanism in HPV-mediated cervical carcinogenesis.
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