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Theranostics 2023; 13(3):1130-1149. doi:10.7150/thno.78091 This issue Cite

Research Paper

Human papillomavirus E6/E7 oncoproteins promote radiotherapy-mediated tumor suppression by globally hijacking host DNA damage repair

Diane Bruyere¹, Patrick Roncarati¹, Alizee Lebeau¹, Thomas Lerho¹, Florian Poulain², Elodie Hendrick¹, Charlotte Pilard¹, Celia Reynders¹, Marie Ancion¹, Margaux Luyckx¹, Michael Renard¹, Yves Jacob³, Jean-Claude Twizere⁴, Raphael Peiffer⁵, Olivier Peulen⁵, Philippe Delvenne^1,6, Pascale Hubert¹, Alison McBride⁷, Nicolas Gillet², Murielle Masson⁸, Michael Herfs^1✉

1. Laboratory of Experimental Pathology, GIGA-Cancer, University of Liege, 4000 Liege, Belgium.
2. Namur Research Institute for Life Sciences (NARILIS), Integrated Veterinary Research Unit (URVI), University of Namur, Namur, Belgium.
3. Unit of Molecular Genetics of RNA Viruses, UMR 3569, CNRS, Pasteur Institute, University of Paris Diderot, 75015 Paris, France.
4. Laboratory of Signaling and Protein Interactions, GIGA-Molecular Biology of Diseases, University of Liege, 4000 Liege, Belgium.
5. Metastasis Research Laboratory, GIGA-Cancer, University of Liege, 4000 Liege, Belgium.
6. Department of Pathology, University Hospital of Liege, 4000 Liege, Belgium.
7. Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, 20892, USA.
8. Biothechnology Superior School, UMR 7242, CNRS, University of Strasbourg, 67412 Illkirch, France.

✉ Corresponding author: Michael Herfs, PhD Laboratory of Experimental Pathology, GIGA-Cancer, B23 +4 University of Liege 4000 Liege Belgium Tel: (+32) 43664282 Email: M.Herfsbe

Abstract

Rationale: Whatever the mucosa primary infected, HPV-positive cancers are traditionally associated with a favorable outcome, attributable to a high sensitivity to radiation therapy. However, the direct impact of viral E6/E7 oncoproteins on the intrinsic cellular radiosensitivity (and, globally, on host DNA repair) remains mostly speculative.

Methods: Using several isogenic cell models expressing HPV16 E6 and/or E7, the effect of viral oncoproteins on global DNA damage response was first investigated by in vitro/in vivo approaches. The binary interactome of each individual HPV oncoprotein with factors involved in the various host DNA damage/repair mechanisms was then precisely mapped by Gaussia princeps luciferase complementation assay (and validated by co-immunoprecipitation). The stability/half-life of protein targets for HPV E6 and/or E7 as well as their subcellular localizations were determined. At last, the host genome integrity following E6/E7 expression and the synergy between radiotherapy and compounds targeting DNA repair were analyzed.

Results: We first showed that the sole expression of one viral oncoprotein from HPV16 was able to significantly increase the sensitivity to irradiation of cells without affecting their basal viability parameters. In total, 10 novel targets (CHEK2, CLK2, CLK2/3, ERCC3, MNAT1, PER1, RMI1, RPA1, UVSSA and XRCC6) for E6 and 11 (ALKBH2, CHEK2, DNA2, DUT, ENDOV, ERCC3, PARP3, PMS1, PNKP, POLDIP2 and RBBP8) for E7 were identified. Importantly, not degraded following their interaction with E6 or E7, these proteins have been shown to be less linked to host DNA and to colocalize with HPV replication foci, denoting their crucial implication in viral life cycle. Finally, we found that E6/E7 oncoproteins globally jeopardize host genome integrity, increase the cellular sensitivity to DNA repair inhibitors and enhance their synergy with radiotherapy.

Conclusion: Taken together, our findings provide a molecular insight into the direct hijacking of host DNA damage/repair responses by HPV oncoproteins, demonstrate the significant impact of this phenomenon on both intrinsic cellular radiosensitivity and host DNA integrity and suggest novel connected therapeutic vulnerabilities.

Keywords: human papillomavirus, DNA damage and repair, radiotherapy, protein-protein interactome.

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